Marilyn Renfree

Physical map of two tammar wallaby chromosomes: A strategy for mapping in non-model mammals

Publisher: Springer Science and Business Media LLC

Date: 08-11-2008

DOI: 10.1007/S10577-008-1266-Y

Abstract: Marsupials are especially valuable for comparative genomic studies of mammals. Two distantly related model marsupials have been sequenced: the South American opossum (Monodelphis domestica) and the tammar wallaby (Macropus eugenii), which last shared a common ancestor about 70 Mya. The six-fold opossum genome sequence has been assembled and assigned to chromosomes with the help of a cytogenetic map. A good cytogenetic map will be even more essential for assembly and anchoring of the two-fold wallaby genome. As a start to generating a physical map of gene locations on wallaby chromosomes, we focused on two chromosomes sharing homology with the human X, wallaby chromosomes X and 5. We devised an efficient strategy for mapping large conserved synteny blocks in non-model mammals, and applied this to generate dense maps of the X and 'neo-X' regions and to determine the arrangement of large conserved synteny blocks on chromosome 5. Comparisons between the wallaby and opossum chromosome maps revealed many rearrangements, highlighting the need for comparative gene mapping between South American and Australian marsupials. Frequent rearrangement of the X, along with the absence of a marsupial XIST gene, suggests that inactivation of the marsupial X chromosome does not depend on a whole-chromosome repression by a control locus.

Intrauterine development after diapause in the marsupial Macropus eugenii

Publisher: Elsevier BV

Date: 05-1973

DOI: 10.1016/0012-1606(73)90217-0

Abstract: How do children of immigrants consistently outperform children of native-born U.S. parents, in spite of lower familial resources? Using the Transition to Adulthood Study of the Panel Study of Income Dynamics, children of immigrant and native-born parents completing high school in 2005-13 are followed as they move into the young adult years. Children of immigrants are more likely to enroll in college, be employed or in school, and less likely to have a criminal record as young adults or to have a child than children of nonimmigrants. This is not a result of immigrant parentage but due primarily to greater parental educational expectations immigrants enjoy a differential return to parental expectations for boys' college enrollment as well. Reading skills and activity patterns in the secondary school years also contribute to better outcomes. Children of immigrants are better able to translate their reading comprehension skills to college or employment later on.

Ultrasound attenuation computed tomography assessment of PAGAT gel dose

Publisher: IOP Publishing

Date: 22-07-2014

DOI: 10.1088/0031-9155/59/15/N129

Embryo arrest and reactivation: potential candidates controlling embryonic diapause in the tammar wallaby and mink†

Publisher: Oxford University Press (OUP)

Date: 31-03-2017

DOI: 10.1093/BIOLRE/IOX019

Abstract: Embryonic diapause is a period of developmental arrest which requires coordination of a molecular cross-talk between the endometrium and blastocyst to ensure a successful reactivation, but the exact mechanisms are undefined. The objectives of this study were to screen the tammar blastocyst for potential diapause control factors and to investigate the potential for members of the epidermal growth factor (EGF) family to coordinate reactivation. A select number of factors were also examined in the mink to determine whether their expression patterns were conserved across diapause species. The full-length sequences of the tammar genes of interest were first cloned to establish their level of sequence conservation with other mammals. The uterine expression of EGF family members EGF and heparin-binding EGF (HBEGF) and their receptors (EGFR and erb-b2 receptor tyrosine kinase 4 (ERBB4)) was determined by quantitative reverse-transcriptase polymerase chain reaction (RT-PCR) and immunohistochemistry. Both HBEGF and EGF were significantly upregulated at reactivation compared to diapause. In the blastocyst, the expression of the potential diapause factors Forkhead box class O family members (FOXO1, FOXO3, and FOXO4), tumor protein 53 (TP53), cyclin-dependent kinase inhibitor 1A (CDKN1A), and the EGF family were examined by RT-PCR and immunofluorescence. Nuclear (and hence active) FOXO expression was confirmed for the first time in a mammalian diapause blastocyst in both the tammar and the mink-CDKN1A was also expressed, but TP53 is not involved and EGFR was not detected in the blastocyst. These results indicate that the EGF family, FOXOs, and CDKN1A are promising candidates for the molecular control of embryonic diapause in mammals.

Characterisation of major histocompatibility complex class I genes at the fetal-maternal interface of marsupials.

Publisher: Springer Science and Business Media LLC

Date: 09-05-2015

DOI: 10.1007/S00251-015-0842-5

Abstract: Major histocompatibility complex class I molecules (MHC-I) are expressed at the cell surface and are responsible for the presentation of self and non-self antigen repertoires to the immune system. Eutherian mammals express both classical and non-classical MHC-I molecules in the placenta, the latter of which are thought to modulate the maternal immune response during pregnancy. Marsupials last shared a common ancestor with eutherian mammals such as humans and mice over 160 million years ago. Since, like eutherians, they have an intra-uterine development dependent on a placenta, albeit a short-lived and less invasive one, they provide an opportunity to investigate the evolution of MHC-I expression at the fetal-maternal interface. We have characterised MHC-I mRNA expression in reproductive tissues of the tammar wallaby (Macropus eugenii) from the time of placental attachment to day 25 of the 26.5 day pregnancy. Putative classical MHC-I genes were expressed in the choriovitelline placenta, fetus, and gravid endometrium throughout the whole of this period. The MHC-I classical sequences were phylogenetically most similar to the Maeu-UC (50/100 clones) and Maeu-UA genes (7/100 clones). Expression of three non-classical MHC-I genes (Maeu-UD, Maeu-UK and Maeu-UM) were also present in placental s les. The results suggest that expression of classical and non-classical MHC-I genes in extant marsupial and eutherian mammals may have been necessary for the evolution of the ancestral therian placenta and survival of the mammalian fetus at the maternal-fetal interface.

Maturation of the growth axis in marsupials occurs gradually during post-natal life and over an equivalent developmental stage relative to eutherian species

Publisher: Elsevier BV

Date: 02-2012

DOI: 10.1016/J.MCE.2011.10.016

Abstract: The separation of a nutrition-responsive insulin-like growth factor (IGF) system and a growth hormone (GH) responsive IGF system to control pre- and post-natal growth of developing mammals may originate from the constraints imposed by intra-uterine development. In eutherian species that deliver relatively precocial young, maturation of the GH regulatory system is coincident with the time of birth. We measured the hepatic expression of the four key growth axis genes GH-receptor, IGF-1 and -2, and IGFBBP-3, and plasma protein concentrations of IGF-1 from late fetal life through to adult stages of a marsupial, the tammar wallaby. The data clearly show that maturation of GH-regulated growth in marsupials occurs gradually over the course of post-natal life at an equivalent developmental stage to that of precocial eutherian mammals. This suggests that the timing of GH-regulated growth in marsupials is not related to parturition but instead to the relative developmental stage.

Evolution of coding and non-coding genes in HOX clusters of a marsupial

Publisher: Springer Science and Business Media LLC

Date: 18-06-2020

DOI: 10.1186/1471-2164-13-251

Abstract: The HOX gene clusters are thought to be highly conserved amongst mammals and other vertebrates, but the long non-coding RNAs have only been studied in detail in human and mouse. The sequencing of the kangaroo genome provides an opportunity to use comparative analyses to compare the HOX clusters of a mammal with a distinct body plan to those of other mammals. Here we report a comparative analysis of HOX gene clusters between an Australian marsupial of the kangaroo family and the eutherians. There was a strikingly high level of conservation of HOX gene sequence and structure and non-protein coding genes including the microRNAs miR-196a , miR-196b , miR-10a and miR-10b and the long non-coding RNAs HOTAIR , HOTAIRM1 and HOX A11AS that play critical roles in regulating gene expression and controlling development. By microRNA deep sequencing and comparative genomic analyses, two conserved microRNAs ( miR-10a and miR-10b ) were identified and one new candidate microRNA with typical hairpin precursor structure that is expressed in both fibroblasts and testes was found. The prediction of microRNA target analysis showed that several known microRNA targets, such as miR-10 , miR-414 and miR-464 , were found in the tammar HOX clusters. In addition, several novel and putative miRNAs were identified that originated from elsewhere in the tammar genome and that target the tammar HOXB and HOXD clusters. This study confirms that the emergence of known long non-coding RNAs in the HOX clusters clearly predate the marsupial-eutherian ergence 160 Ma ago. It also identified a new potentially functional microRNA as well as conserved miRNAs. These non-coding RNAs may participate in the regulation of HOX genes to influence the body plan of this marsupial.

Pulse-echo ultrasound transit time spectroscopy: A comparison of experimental measurement and simulation prediction

Publisher: SAGE Publications

Date: 18-11-2015

DOI: 10.1177/0954411915615911

Abstract: Considering ultrasound propagation through complex composite media as an array of parallel sonic rays, a comparison of computer-simulated prediction with experimental data has previously been reported for transmission mode (where one transducer serves as transmitter, the other as receiver) in a series of 10 acrylic step-wedge s les, immersed in water, exhibiting varying degrees of transit time inhomogeneity. In this study, the same s les were used but in pulse-echo mode, where the same ultrasound transducer served as both transmitter and receiver, detecting both ‘primary’ (internal s le interface) and ‘secondary’ (external s le interface) echoes. A transit time spectrum was derived, describing the proportion of sonic rays with a particular transit time. A computer simulation was performed to predict the transit time and litude of various echoes created, and compared with experimental data. Applying an litude-tolerance analysis, 91.7% ± 3.7% of the simulated data were within ±1 standard deviation of the experimentally measured litude-time data. Correlation of predicted and experimental transit time spectra provided coefficients of determination (R 2 %) ranging from 100.0% to 96.8% for the various s les tested. The results acquired from this study provide good evidence for the concept of parallel sonic rays. Furthermore, deconvolution of experimental input and output signals has been shown to provide an effective method to identify echoes otherwise lost due to phase cancellation. Potential applications of pulse-echo ultrasound transit time spectroscopy include improvement of ultrasound image fidelity by improving spatial resolution and reducing phase interference artefacts.

Erratum: Genome analysis of the platypus reveals unique signatures of evolution

Publisher: Springer Science and Business Media LLC

Date: 09-2008

DOI: 10.1038/NATURE07253

Evolution of sex determination and the Y chromosome: SRY-related sequences in marsupials

Publisher: Springer Science and Business Media LLC

Date: 10-1992

DOI: 10.1038/359531A0

Abstract: In mammals, testis determination is under the control of the testis-determining factor borne by the Y chromosome. SRY, a gene cloned from the sex-determining region of the human Y chromosome, has been equated with the testis-determining factor in man and mouse. We have used a human SRY probe to identify and clone related genes from the Y chromosome of two marsupial species. Comparisons of eutherian and metatherian Y-located SRY sequences suggest rapid evolution of these genes, especially outside the region encoding the DNA-binding HMG box. The SRY homologues, together with the mouse Ube1y homologues, are the first genes to be identified on the marsupial Y chromosome.

Reference genome of the endangered eastern quoll (Dasyurus viverrinus)

Publisher: Cold Spring Harbor Laboratory

Date: 07-09-2023

DOI: 10.1101/2023.09.06.556354

Potential for ultrasound transit time spectroscopy to improve axial resolution

Publisher: Elsevier BV

Date: 04-2018

DOI: 10.1016/J.APACOUST.2017.12.019

Getting out of a mammalian egg: The egg tooth and caruncle of the echidna

Publisher: Cold Spring Harbor Laboratory

Date: 13-10-2021

DOI: 10.1101/2021.10.12.464116

Abstract: In the short-beaked echidna, Tachyglossus aculeatus , after an initial period of in utero development, the egg is laid in the pouch and incubated for 10 days. During this time, the fetuses develop an egg tooth and caruncle to help them hatch. However, there are only a few historical references that describe the development of the monotreme egg tooth. Using unprecedented access to echidna pre- and post-hatching tissues, the egg tooth and caruncle were assessed by micro-CT, histology and immunofluorescence, to map the changes at the morphological and molecular level. Unlike mammalian tooth germs that develop by invagination of a placode, the echidna egg tooth developed by evagination, similar to that of the first teeth in some reptiles. The egg tooth ankylosed to the premaxilla, rather than forming a mammalian thecodont attachment, with loss of the egg tooth post-hatching associated with high levels of odontoclasts, and apoptosis. The caruncle formed as a separate mineralisation from the adjacent nasal capsule, and as observed in birds and turtles, the nasal region epithelium expressed markers of cornification. Together, this highlights that the monotreme egg tooth shares many similarities with reptilian teeth, suggesting that this tooth is conserved from a common ancestor of mammals and reptiles.

Androgen physiology: unsolved problems at the millennium

Publisher: Elsevier BV

Date: 12-2002

DOI: 10.1016/S0303-7207(02)00362-3

Abstract: Androgen physiology differs from that of other steroid hormones in two major regards. First, testosterone, the predominant circulating testicular androgen, is both an active hormone and a prohormone for the formation of a more active androgen, the 5alpha-reduced steroid dihydrotestosterone. Genetic evidence indicates that testosterone and dihydrotestosterone work via a common intracellular receptor, and studies involving in vitro reporter gene assays and intact mice in which both steroid 5alpha-reductase isoenzymes have been disrupted by homologous recombination indicate that dihydrotestosterone acts during embryonic life to lify hormonal signals that can be mediated by testosterone at higher concentrations. However, in post-embryonic life dihydrotestosterone plays unique roles that have not been elucidated. Studies of other 5alpha-reduced steroids, including the plant hormone brassinolide, the hog pheromones androstanol and androstenol, and 5alpha-dihydroprogesterone (in horses and elephants) indicate that this reaction serves different functions in different systems. Second, during embryonic life androgen causes the formation of the male urogenital tract and hence is responsible for development of the tissues that serve as the major sites of androgen action in postnatal life. It has been generally assumed that androgens virilize the male fetus by the same mechanisms as in the adult, namely by the conversion of circulating testosterone to dihydrotestosterone in target tissues. However, in marsupial mammals there is no sexual dimorphism in the levels of testosterone or dihydrotestosterone at the time the male phenotype forms, and in the pouch young of one marsupial, the tammar wallaby, the testes secrete another 5alpha-reduced steroid, 5alpha-androstane-3alpha, 17beta-diol (5alpha-adiol), into plasma. The administration of 5alpha-adiol to female pouch young causes profound virilization of the urogenital sinus and external genitalia, but within target tissues 5alpha-adiol appears to work after oxidation to dihydrotestosterone. Thus, two separate mechanisms evolved for the formation of dihydrotestosterone in target tissues. 5alpha-adiol is the predominant androgen in neonatal testes in several placental mammals, but it is unclear whether it plays a similar role in other mammalian species.

Reproduction in male swamp wallabies (Wallabia bicolor): puberty and the effects of season

Publisher: Wiley

Date: 31-08-2007

DOI: 10.1111/J.1469-7580.2007.00785.X

Mammalian diversity: gametes, embryos and reproduction

Publisher: CSIRO Publishing

Date: 2006

DOI: 10.1071/RD05137

Abstract: The class Mammalia is composed of approximately 4800 extant species. These mammalian species are ided into three subclasses that include the monotremes, marsupials and eutherians. Monotremes are remarkable because these mammals are born from eggs laid outside of the mother’s body. Marsupial mammals have relatively short gestation periods and give birth to highly altricial young that continue a significant amount of ‘fetal’ development after birth, supported by a highly sophisticated lactation. Less than 10% of mammalian species are monotremes or marsupials, so the great majority of mammals are grouped into the subclass Eutheria, including mouse and human. Mammals exhibit great variety in morphology, physiology and reproduction. In the present article, we highlight some of this remarkable ersity relative to the mouse, one of the most widely used mammalian model organisms, and human. This ersity creates challenges and opportunities for gamete and embryo collection, culture and transfer technologies.

The prevalence of REM-related obstructive sleep apnoea is reduced by the AASM 2012 hypopnoea criteria

Publisher: Springer Science and Business Media LLC

Date: 09-06-2018

DOI: 10.1007/S11325-017-1526-1

Abstract: The variations in reported prevalence of rapid eye movement-related obstructive sleep apnoea (REM-OSA) have been attributed to different definitions, although the effect of hypopnoea criteria has not been previously investigated. Within this retrospective study, 134 of 382 consecutive patients undertaking polysomnography (PSG) for the suspicion of OSA met the inclusion criteria. PSGs were scored using both the 2007 AASM recommended hypopnoea criteria (AASM Incorporation of the AASM This study demonstrates that in comparison with AASM

A Dual Role for SHH during Phallus Development in a Marsupial

Publisher: S. Karger AG

Date: 2014

DOI: 10.1159/000357927

Abstract: The mammalian phallus arises from identical primordia in both sexes and is patterned in part by the key morphogen Sonic hedgehog (SHH). We have investigated SHH and other morphogens during phallus development in the tammar wallaby. In this marsupial, testis differentiation and androgen production occurs just after birth, but it takes a further 50-60 days before the phallus becomes sexually dimorphic. One day before birth, i SHH /i was expressed in both sexes in the urethral epithelium. In males, there was a marked upregulation of i SHH /i , i GLI2, /i and i AR /i at day 50 postpartum, a time when testicular androgen production falls. i SHH /i , i GLI2, /i and i AR /i were downregulated in female pouch young treated with androstanediol from days 24-50, but not when treatments were begun at day 29, suggesting an early window of androgen sensitivity. i SHH /i , i GLI2, /i and i AR /i expression in the phallus of males castrated at day 23 did not differ from controls, but there was an increase in i SHH /i and i GLI2 /i and a decrease in i FGF8 /i and i BMP4 /i expression when the animals were castrated at day 29. These results suggest that the early patterning by SHH is androgen-independent followed by an androgen-dependent window of sensitivity and a sharp rise in i SHH /i expression after androgen withdrawal at day 50.

Seasonal changes in a population of the nectar‐feeding marsupial Tarsipes spencerae (Marsupialia: Tarsipedidae)

Publisher: Wiley

Date: 10-1981

DOI: 10.1111/J.1469-7998.1981.TB03464.X

Resurrection of DNA Function In Vivo from an Extinct Genome

Publisher: Public Library of Science (PLoS)

Date: 21-05-2008

DOI: 10.1371/JOURNAL.PONE.0002240

The enigma of embryonic diapause

Publisher: The Company of Biologists

Date: 15-09-2017

DOI: 10.1242/DEV.148213

Abstract: Embryonic diapause – a period of embryonic suspension at the blastocyst stage – is a fascinating phenomenon that occurs in over 130 species of mammals, ranging from bears and badgers to mice and marsupials. It might even occur in humans. During diapause, there is minimal cell ision and greatly reduced metabolism, and development is put on hold. Yet there are no ill effects for the pregnancy when it eventually continues. Multiple factors can induce diapause, including seasonal supplies of food, temperature, photoperiod and lactation. The successful reactivation and continuation of pregnancy then requires a viable embryo, a receptive uterus and effective molecular communication between the two. But how do the blastocysts survive and remain viable during this period of time, which can be up to a year in some cases? And what are the signals that bring it out of suspended animation? Here, we provide an overview of the process of diapause and address these questions, focussing on recent molecular data.

Ancient antimicrobial peptides kill Antibiotic-Resistant pathogens: Australian mammals provide new options

Publisher: Public Library of Science (PLoS)

Date: 30-08-2011

DOI: 10.1371/JOURNAL.PONE.0024030

Intra-cytoplasmic sperm injection in a marsupial

Publisher: Bioscientifica

Date: 11-2004

DOI: 10.1530/REP.1.00270

Abstract: Here we report the first use of intra-cytoplasmic sperm injection (ICSI) in a marsupial, the tammar wallaby ( Macropus eugenii ), to achieve in vitro fertilization and cleavage. A single epididymal spermatozoon was injected into the cytoplasm of each mature oocyte collected from Graafian follicles or from the oviduct within hours of ovulation. The day after sperm injection, oocytes were assessed for the presence of pronuclei and polar body extrusion and in vitro development was monitored for up to 4 days. After ICSI, three of four (75%) follicular and four of eight (50%) tubal oocytes underwent cleavage. The cleavage pattern was similar to that previously reported for in vivo fertilized oocytes placed in culture, where development also halted at the 4- to 8-cell stage. One-third of injected oocytes completed the second cleavage ision, but only a single embryo reached the 8-cell stage. The success of ICSI in the tammar wallaby provided an opportunity to examine the influence of the mucoid coat that is deposited around oocytes passing through the oviduct after fertilization. The presence of a mucoid coat in tubal oocytes did not prevent fertilization by ICSI and the oocytes cleaved in vitro to a similar stage as follicular oocytes lacking a mucoid coat. Cell–zona and cell–cell adhesion occurred in embryos from follicular oocytes, suggesting that the mucoid coat is not essential for these processes. However, blastomeres were more closely apposed in embryos from tubal oocytes and cell–cell adhesion was more pronounced, indicating that the mucoid coat may be involved in maintaining the integrity of the conceptus during cleavage.

Adaptation and conservation insights from the koala genome

Publisher: Springer Science and Business Media LLC

Date: 02-07-2018

DOI: 10.1038/S41588-018-0153-5

A high frequency current source converter with adjustable magnitude to drive high power piezoelectric transducers

Publisher: IEEE

Date: 09-2012

DOI: 10.1109/EPEPEMC.2012.6397206

Discrete Hedgehog Factor Expression and Action in the Developing Phallus

Publisher: MDPI AG

Date: 12-02-2020

DOI: 10.3390/IJMS21041237

Abstract: Hypospadias is a failure of urethral closure within the penis occurring in 1 in 125 boys at birth and is increasing in frequency. While paracrine hedgehog signalling is implicated in the process of urethral closure, how these factors act on a tissue level to execute closure itself is unknown. This study aimed to understand the role of different hedgehog signalling members in urethral closure. The tammar wallaby (Macropus eugenii) provides a unique system to understand urethral closure as it allows direct treatment of developing offspring because mothers give birth to young before urethral closure begins. Wallaby pouch young were treated with vehicle or oestradiol (known to induce hypospadias in males) and s les subjected to RNAseq for differential expression and gene ontology analyses. Localisation of Sonic Hedgehog (SHH) and Indian Hedgehog (IHH), as well as the transcription factor SOX9, were assessed in normal phallus tissue using immunofluorescence. Normal tissue culture explants were treated with SHH or IHH and analysed for AR, ESR1, PTCH1, GLI2, SOX9, IHH and SHH expression by qPCR. Gene ontology analysis showed enrichment for bone differentiation terms in male s les compared with either female s les or males treated with oestradiol. Expression of SHH and IHH localised to specific tissue areas during development, akin to their compartmentalised expression in developing bone. Treatment of phallus explants with SHH or IHH induced factor-specific expression of genes associated with bone differentiation. This reveals a potential developmental interaction involved in urethral closure that mimics bone differentiation and incorporates discrete hedgehog activity within the developing phallus and phallic urethra.

Frequency Independence of Ultrasound Transit Time Spectroscopy

Publisher: Springer International Publishing

Date: 2015

DOI: 10.1007/978-3-319-11776-8_10

Biosynthesis and secretion of testosterone by adrenal tissue from the North American opossum, Didelphis virginiana, and the effects of tropic hormone stimulation

Publisher: Elsevier BV

Date: 10-1975

DOI: 10.1016/0016-6480(75)90236-1

Abstract: Rabbits are not usually susceptible to intestinal Shigella infection without extensive pretreatment, including starvation and administration of antimicrobial, antimotility, and toxic agents (carbon tetrachloride). Most animals infected this way die rapidly and do not always develop colonic lesions and signs of dysentery. We describe here a successful experimental infection in the adult rabbit which does not require preparatory treatment and which reproduced characteristic features of human shigellosis. Unstarved, untreated adult rabbits were infected by direct inoculation of virulent Shigella flexneri 2a (10 ml of 10(7) bacteria per ml) into the proximal colon after ligation of the distal cecum (cecal bypass). Within 24 h of infection, most inoculated animals consistently developed clinical dysentery, characterized by liquid stool mixed with mucus and blood, leukocytosis, anorexia, and weight loss. Histologically, there were edema, exudation, superficial ulceration, and polymorphonuclear infiltrations in the lamina propria crypt abscess formation focal hemorrhages and the presence of immunohistochemically stained S. flexneri in the colonic mucosa. Successful bacterial colonization was indicated by the isolation of the challenge strain of S. flexneri 2a from the colonic contents. None of the control rabbits challenged with nonvirulent S. flexneri or without cecal bypass developed dysentery or colitis. We conclude that successful Shigella infection can be induced by direct colonic inoculation with virulent S. flexneri 2a in adult rabbits without starvation and pretreatment. The colitis is dependent on the virulence of the bacteria and on the cecal bypass. This model should be useful in studies of the immunopathogenesis of Shigella infection.

Lower material stiffness in rupture-repaired Achilles tendon during walking: transmission-mode ultrasound for post-surgical tendon evaluation

Publisher: Springer Science and Business Media LLC

Date: 28-06-2017

DOI: 10.1007/S00167-017-4624-5

Abstract: This cross-sectional study used transmission-mode ultrasound to evaluate dynamic tendon properties during walking in surgically repaired and contralateral Achilles tendon (AT), with a median (range) post-operative period of 22 (4-58) months. It was hypothesised that the axial transmission speed of ultrasound (TSOU) during walking would be slower, indicating lower material stiffness in repaired compared with contralateral AT. Ten patients [median (range) age 47 (37-69) years height 180 (170-189) cm weight 93 (62-119) kg], who had undergone open surgical repair of the AT and were clinically recovered according to their treating clinicians, walked barefoot on a treadmill at self-selected speed (1.0 ± 0.2 m/s). Synchronous measures of TSOU, sagittal ankle motion, vertical ground reaction force (GRF), and spatiotemporal gait parameters were recorded during 20 s of steady-state walking. Paired t tests were used to evaluate potential between-limb differences in TSOU, GRF, ankle motion, and spatiotemporal gait parameters. TSOU was significantly lower (≈175 m/s) in the repaired than in the contralateral AT over the entire gait cycle (P < 0.05). Sagittal ankle motion was significantly greater (≈3°) in the repaired than in the contralateral limb (P = 0.036). There were no significant differences in GRF or spatiotemporal parameters between limbs. Repaired AT was characterised by a lower TSOU, reflecting a lower material stiffness in the repaired tendon than in the contralateral tendon. A lower material stiffness may underpin greater ankle joint motion of the repaired limb during walking and long-term deficits in the muscle-tendon unit reported with AT repair. Treatment and rehabilitation approaches that focus on increasing the material stiffness of the repaired AT may be clinically beneficial. Transmission-mode ultrasound would seem useful for quantifying tendon properties post AT rupture repair and may have the potential to in idually guide rehabilitation programmes, thereby aiding safer return to physical activity. II.

Uterine morphology during diapause and early pregnancy in the tammar wallaby (Macropus eugenii)

Publisher: Wiley

Date: 11-05-2016

DOI: 10.1111/JOA.12483

Steroid Hormone Content of the Gonads of the Tammar Wallaby during Sexual Differentiation1

Publisher: Oxford University Press (OUP)

Date: 10-1992

DOI: 10.1095/BIOLREPROD47.4.644

Abstract: The gonads of the tammar wallaby, Macropus eugenii, are sexually indifferent at birth (Day 0) despite the fact that phenotypic sexual differentiation has already commenced as evidenced by the presence of a scrotum in males and mammary anlagen in females. The seminiferous cords of the testis first become clearly recognizable on Day 2 of pouch life, and ovarian differentiation is recognizable by Day 10. To monitor the endocrine development of the gonads during sexual differentiation of the urogenital tract, we measured the steroid hormone content in 92 pools of gonads from male and female tammar pouch young from the day of birth to 206 days of pouch life. Progesterone, estradiol, and dihydrotestosterone concentrations were low (less than 0.05 ng/mg protein) in both ovaries and testes at all stages examined, and testosterone concentrations were uniformly low in ovaries. Testosterone concentrations in testes were low on Days 0-4, averaging about 0.2 ng/mg protein they rose by Days 5-10 to an average of 0.9 ng/mg protein, remained elevated until about Day 40, and thereafter fell to values similar to those in the ovaries. The phallus and urogenital sinus were able to convert testosterone to dihydrotestosterone from the earliest stages examined (Days 10 and 11). Thus in the tammar wallaby, as in eutherian mammals, testosterone is the androgen secreted by the developing testis, and dihydrotestosterone is formed in certain androgen target tissues.(ABSTRACT TRUNCATED AT 250 WORDS)

Reproduction in females of the feathertail glider Acrobates pygmaeus (Marsupialia)

Publisher: Wiley

Date: 10-1988

DOI: 10.1111/J.1469-7998.1988.TB02427.X

Dissimilar trend of nonlinearity in ultrasound transducers and systems at resonance and non-resonance frequencies

Publisher: Elsevier BV

Date: 02-2017

DOI: 10.1016/J.ULTRAS.2016.09.023

Abstract: Several factors can affect performance of an ultrasound system such as quality of excitation signal and ultrasound transducer behaviour. Nonlinearity of piezoelectric ultrasound transducers is a key determinant in designing a proper driving power supply. Although, the nonlinearity of piezoelectric transducer impedance has been discussed in different literatures, the trend of the nonlinearity at different frequencies with respect to excitation voltage variations has not been clearly investigated in practice. In this paper, to demonstrate how the nonlinearity behaves, a sandwich piezoceramic transducer was excited at different frequencies. Different excitation signals were generated using a linear power lifier and a multilevel converter within a range of 30-200V. Empirical relation was developed to express the resistance of the piezoelectric transducer as a nonlinear function of both excitation voltage and resonance frequency. The impedance measurements revealed that at higher voltage ranges, the piezoelectric transducer can be easily saturated. Also, it was shown that for the developed ultrasound system composed of two transducers (one transmitter and one receiver), the output voltage measured across receiver is a function of a voltage across the resistor in the RLC branches and is related to the resonance frequencies of the ultrasound transducer.

A hybrid radiation detector for simultaneous spatial and temporal dosimetry

Publisher: Springer Science and Business Media LLC

Date: 16-06-2011

DOI: 10.1007/S13246-011-0081-5

Abstract: In this feasibility study an organic plastic scintillator is calibrated against ionisation chamber measurements and then embedded in a polymer gel dosimeter to obtain a quasi-4D radiation detector. This hybrid dosimeter was irradiated with megavoltage x-rays from a linear accelerator, with temporal measurements of the dose rate being acquired by the scintillator and spatial measurements acquired with the gel dosimeter. The detectors employed in this study are radiologically equivalent and we show that neither detector perturbs the intensity of the radiation field of the other. By employing these detectors in concert, spatial and temporal variations in the radiation intensity can now be detected and gel dosimeters can be calibrated for absolute dose from a single irradiation.

Expression and protein localisation of IGF2in the marsupial placenta

Publisher: Springer Science and Business Media LLC

Date: 20-02-2008

DOI: 10.1186/1471-213X-8-17

Abstract: In eutherian mammals, genomic imprinting is critical for normal placentation and embryo survival. Insulin-like growth factor 2 ( IGF2 ) is imprinted in the placenta of both eutherians and marsupials, but its function, or that of any imprinted gene, has not been investigated in any marsupial. This study examines the role of IGF2 in the yolk sac placenta of the tammar wallaby, Macropus eugenii . IGF2 mRNA and protein were produced in the marsupial placenta. Both IGF2 receptors were present in the placenta, and presumably mediate IGF2 mitogenic actions. IGF2 mRNA levels were highest in the vascular region of the yolk sac placenta. IGF2 increased vascular endothelial growth factor expression in placental explant cultures, suggesting that IGF2 promotes vascularisation of the yolk sac. This is the first demonstration of a physiological role for any imprinted gene in marsupial placentation. The conserved imprinting of IGF2 in this marsupial and in all eutherian species so far investigated, but not in monotremes, suggests that imprinting of this gene may have originated in the placenta of the therian ancestor.

Selection on Phalanx Development in the Evolution of the Bird Wing

Publisher: Oxford University Press (OUP)

Date: 23-06-2021

DOI: 10.1093/MOLBEV/MSAB150

Abstract: The frameshift hypothesis is a widely accepted model of bird wing evolution. This hypothesis postulates a shift in positional values, or molecular-developmental identity, that caused a change in digit phenotype. The hypothesis synthesized developmental and paleontological data on wing digit homology. The “most anterior digit” (MAD) hypothesis presents an alternative view based on changes in transcriptional regulation in the limb. The molecular evidence for both hypotheses is that the MAD expresses Hoxd13 but not Hoxd11 and Hoxd12. This digit I “signature” is thought to characterize all amniotes. Here, we studied Hoxd expression patterns in a phylogenetic s le of 18 amniotes. Instead of a conserved molecular signature in digit I, we find wide variation of Hoxd11, Hoxd12, and Hoxd13 expression in digit I. Patterns of apoptosis, and Sox9 expression, a marker of the phalanx-forming region, suggest that phalanges were lost from wing digit IV because of early arrest of the phalanx-forming region followed by cell death. Finally, we show that multiple amniote lineages lost phalanges with no frameshift. Our findings suggest that the bird wing evolved by targeted loss of phalanges under selection. Consistent with our view, some recent phylogenies based on dinosaur fossils eliminate the need to postulate a frameshift in the first place. We suggest that the phenotype of the Archaeopteryx lithographica wing is also consistent with phalanx loss. More broadly, our results support a gradualist model of evolution based on tinkering with developmental gene expression.

Estimation of mechanical stiffness by finite element analysis of ultrasound computed tomography (UCT-FEA); a comparison with X-ray µCT based FEA in cancellous bone replica models

Publisher: Elsevier BV

Date: 04-2018

DOI: 10.1016/J.APACOUST.2017.12.002

Deslorelin implants in free-ranging female eastern grey kangaroos (Macropus giganteus): mechanism of action and contraceptive efficacy

Publisher: CSIRO Publishing

Date: 2013

DOI: 10.1071/WR13050

Abstract: Context Fertility control offers a non-lethal management technique for iconic yet overabundant wildlife. Slow-release hormonal implants containing deslorelin show promise for managing free-ranging populations, particularly in peri-urban reserves, but most studies have been limited to captivity. Aims We investigated the efficacy and mechanism of deslorelin implants in free-ranging female eastern grey kangaroos (Macropus giganteus) under realistic management conditions. Methods We assigned females to a deslorelin (9.4 mg, n = 53) or placebo (n = 56) group at three peri-urban sites in Victoria, Australia, and monitored reproductive success for 3 years by observing young in the pouch. We tested the plasma LH response of control and treated females to exogenous GnRH, and compared the size of ovarian follicles between the two groups. Key results Deslorelin implants reduced fertility at all three sites. No deslorelin-treated females bred in Year 1 at Anglesea and Serendip versus 42% and 44% of control females respectively. At Plenty Gorge, 60% of deslorelin-treated females bred in Year 1 versus 100% of control females. In Year 2, between 11% and 39% of the treated females bred versus between 82% and 100% of control females at all sites. The contraceptive efficacy reduced by Year 3 when between 43% and 57% of the treated females bred versus between 85% and 100% of controls. A GnRH challenge elicited higher plasma LH concentrations in control than in treated females, and unlike untreated females, treated females lacked ovarian follicles mm. Conclusions Deslorelin implants reduced fertility in free-ranging female eastern grey kangaroos over three successive breeding seasons. Chronic exposure to deslorelin desensitised the pituitary gland to GnRH and suppressed follicular development, but did not inhibit the development of a blastocyst, pregnancy or lactation in at least some females that had conceived before treatment. Implications Effective population management using deslorelin implants will require females to be re-treated on multiple occasions because the contraceptive effect lasts only a portion of their reproductive life. This would be practical only at sites where kangaroos are relatively easy to capture. The timing of treatment is also important in a species that undergoes embryonic diapause, particularly at sites providing high-quality habitat.

Enzymes of intermediary metabolism in the fetal fluids of the tammar wallaby, Macropus eugenii

Publisher: Bioscientifica

Date: 02-1973

DOI: 10.1530/JRF.0.0320330

Divergent patterns of meiotic double strand breaks and synapsis initiation dynamics suggest an evolutionary shift in the meiosis program between American and Australian marsupials

Publisher: Cold Spring Harbor Laboratory

Date: 13-02-2023

DOI: 10.1101/2023.02.13.527877

Abstract: In eutherian mammals, hundreds of programmed DNA double-strand breaks (DSBs) are generated at the onset of meiosis. The DNA damage response is then triggered. Although the dynamics of this response is well studied in eutherian mammals, recent findings have revealed different patterns of DNA damage signaling and repair in marsupial mammals. To better characterize these differences, here we analyzed synapsis and the chromosomal distribution of meiotic DSBs markers in three different marsupial species ( Thylamys elegans, Dromiciops gliorides , and Macropus eugenii ) that represent South American and Australian Orders. Our results revealed inter-specific differences in the chromosomal distribution of DNA damage and repair proteins, which were associated with differing synapsis patterns. In the American species T. elegans and D. gliroides , synapsis progressed exclusively from the chromosomal ends towards interstitial regions. This was accompanied by sparse H2AX phosphorylation, mainly accumulating at chromosomal ends, which appeared conspicuously polarized in a bouquet configuration at early stages of prophase I. Accordingly, RAD51 and RPA were mainly localized at chromosomal ends throughout prophaseI in both American marsupials, likely resulting in reduced recombination rates at interstitial positions. In sharp contrast, synapsis initiated at both interstitial and distal chromosomal regions in the Australian representative M. eugenii , γH2AX had a broad nuclear distribution, and RAD51 and RPA foci displayed an even chromosomal distribution. Given the basal evolutionary position of T. elegans , it is likely that the meiotic features reported in this species represent an ancestral pattern in marsupials and that a shift in the meiotic program occurred after the split of D. gliroides and the Australian marsupial clade. Our results open intriguing questions about the regulation and homeostasis of meiotic DSBs in marsupials. The low recombination rates observed at the interstitial chromosomal regions in American marsupials can result in the formation of large linkage groups, thus having an impact in the evolution of their genomes.

Desert hedgehogis a mammal-specific gene expressed during testicular and ovarian development in a marsupial

Publisher: Springer Science and Business Media LLC

Date: 12-2011

DOI: 10.1186/1471-213X-11-72

Abstract: Desert hedgehog ( DHH ) belongs to the hedgehog gene family that act as secreted intercellular signal transducers. DHH is an essential morphogen for normal testicular development and function in both mice and humans but is not present in the avian lineage. Like other hedgehog proteins, DHH signals through the patched (PTCH) receptors 1 and 2. Here we examine the expression and protein distribution of DHH, PTCH1 and PTCH2 in the developing testes of a marsupial mammal (the tammar wallaby) to determine whether DHH signalling is a conserved factor in gonadal development in all therian mammals. DHH , PTCH1 and PTCH2 were present in the marsupial genome and highly conserved with their eutherian orthologues. Phylogenetic analyses indicate that DHH has recently evolved and is a mammal-specific hedgehog orthologue. The marsupial PTCH2 receptor had an additional exon (exon 21a) not annotated in eutherian PTCH2 proteins. Interestingly we found evidence of this exon in humans and show that its translation would result in a truncated protein with functions similar to PTCH1. We also show that DHH expression was not restricted to the testes during gonadal development (as in mice), but was also expressed in the developing ovary. Expression of DHH , PTCH1 and PTCH2 in the adult tammar testis and ovary was consistent with findings in the adult mouse. These data suggest that there is a highly conserved role for DHH signalling in the differentiation and function of the mammalian testis and that DHH may be necessary for marsupial ovarian development. The receptors PTCH1 and PTCH2 are highly conserved mediators of hedgehog signalling in both the developing and adult marsupial gonads. Together these findings indicate DHH is an essential therian mammal-specific morphogen in gonadal development and gametogenesis.

Maternal Regulation of Milk Composition, Milk Production, and Pouch Young Development During Lactation in the Tammar Wallaby (Macropus eugenii )1

Publisher: Oxford University Press (OUP)

Date: 03-2003

DOI: 10.1095/BIOLREPROD.102.005934

Abstract: Specific changes in milk composition during lactation in the tammar wallaby (Macropus eugenii) were correlated with the ages of the developing pouch young (PY). The present experiment was designed to test the hypothesis that the sucking pattern of the PY determines the course of mammary development in the tammar wallaby. To test this hypothesis, groups of 60-day-old PY were fostered repeatedly onto one group of host mothers so that a constant sucking stimulus on the mammary gland was maintained for 56 days to allow the lactational stage to progress 42 days ahead of the age of the young. Analysis of the milk in fostered and control groups showed the timing of changes in the concentration of protein and carbohydrate were essentially unaffected by altering the sucking regime. The only change in milk protein secretion was a small delay in the timing of down-regulation of the secretion of whey acidic protein and early lactation protein in the host tammars. In addition, the rates of growth and development of the foster PY were significantly increased relative to those of the control PY because of ingesting more milk with a higher energy content and different composition than normal for their age. The present study demonstrates that the lactating tammar wallaby regulates both milk composition and the rate of milk production and that these determine the rates of PY growth and development, irrespective of the age of the PY.

Metabolic assessment of wallaby blastocysts during embryonic diapause and subsequent reactivation

Publisher: CSIRO Publishing

Date: 1995

DOI: 10.1071/RD9951157

Abstract: The metabolism of tammar wallaby (Macropus eugenii) blastocysts was analysed by means of quantitative fluorescence microscopy during embryonic diapause and 2, 3, 4, 5, 8 and 10 days after reactivation to determine nutrient preferences during metabolic reactivation of the blastocyst. The surface area of quiescent blastocysts was 0.16 +/- 0.02 mm2 (mean +/- s.e.m.), and increased to 0.44 +/- 0.04 mm2 (P 0.05) by Day 8 after removal of the sucking stimulus of the pouch young (RPY). Day-10 blastocysts, analysed over two successive breeding seasons, were significantly different in size from each other (Group A, 1992: 4.44 +/- 1.47 mm2 Group B, 1993: 18.87 +/- 4.62 mm2 P 0.01), and both groups were significantly different in size from diapausing blastocysts (P 0.01). There was no significant difference in carbohydrate uptake or production by blastocysts during the first five days after RPY. Glucose uptake by blastocysts recovered 8 days after RPY (61.9 +/- 30.0 pmol embryo-1 h-1) was significantly greater than that by Day-0 blastocysts (17.9 +/- 5.5 pmol embryo-1 h-1) and glucose uptake by both groups of Day-10 blastocysts (Group A, 174.0 +/- 28.4 pmol embryo-1 h-1 Group B, 616.0 +/- 239.0 pmol embryo-1 h-1) was significantly different from that by Day-0 blastocysts (P 0.01). Pyruvate uptake by Day-10 blastocysts (Group A, 46.0 +/- 32.2 pmol embryo-1 h-1 Group B, 250.0 +/- 136.0 pmol embryo-1 h-1 P 0.01) increased significantly compared with that by Day-0 blastocysts (6.4 +/- 1.6 pmol embryo-1 h-1 P 0.01). Lactate production by Day-10 blastocysts (Group A, 186.7 +/- 30.3 pmol embryo-1 h-1 Group B, 285 +/- 129 pmol embryo-1 h-1 P 0.01) was also significantly different from that by quiescent blastocysts (41.20 +/- 9.6 pmol embryo-1 h-1). There was a linear relationship between surface area and glucose uptake and surface area and pyruvate uptake (r2 = 0.965 and r2 = 0.971 respectively). Despite increases in carbohydrate uptake, there was a proportional decrease in lactate production indicating an increase in oxidative metabolism during reactivation. This suggests that there may be a metabolic switch at, or around, Day 5 after RPY.

Marsupial Anti-Müllerian Hormone Gene Structure, Regulatory Elements, and Expression1

Publisher: Oxford University Press (OUP)

Date: 2004

DOI: 10.1095/BIOLREPROD.103.020016

Review: Marsupials: Placental Mammals with a Difference

Publisher: Elsevier BV

Date: 03-2010

DOI: 10.1016/J.PLACENTA.2009.12.023

Abstract: The placenta is the most varied organ within the Mammalia. There are many similarities, as well as some differences, between the marsupial embryo and those of eutherian mammals. The most striking difference is the lack of the inner cell mass in the blastocyst which consists solely of a single layer of trophoblast cells. The trophoblast expands and eventually becomes part of the definitive chorio-vitelline placenta. The degree of functional differentiation between the vascular and non-vascular parts of the yolk sac placenta differs between species in the relative surface area that is attached to the endometrium, in trophoblast thickness, in yolk sac fusion with the luminal epithelium and most markedly in the degree of invasiveness. In marsupials, placental physiology has been best studied in the tammar wallaby. Despite the lack of invasion in the tammar, there is nevertheless maternal recognition of pregnancy in response to trophoblast formation. Contrary to popular opinion, the tammar placenta also elaborates hormones: at term it secretes prostaglandin F2alpha and accumulates cortisol, and it expresses genes for hormones such as growth hormone, IGF2 and relaxin. As in eutherian mammals, genomic imprinting is important for placental function. Despite the relatively short period of placentation, it is clear that the trophoblast and the placenta it forms are as important for successful pregnancy in marsupial as in eutherian mammals. Marsupials are certainly placental mammals. However marsupials have an additional trick in their pouches, with the physiologically sophisticated and extended lactation that has allowed them to exchange the umbilical cord for the teat.

Transducer impulse response correction for a deconvolution derived ultrasound transit time spectrum

Publisher: IOP Publishing

Date: 30-08-2018

DOI: 10.1088/1361-6560/AAD8FB

Abstract: Propagation of ultrasound through a complex composite s le may exhibit phase interference between two or more sonic-rays if differences in transit time are less than the pulse length. The transit time spectrum of a test s le, equivalent to its impulse response, was derived through active-set deconvolution of ultrasound signals with, and without, the test s le. The aim of this study was to test the hypothesis that in cases where only the transmit ultrasound transducer's digitally-coded excitation signal is available, hence not the input ultrasound signal without the test s le, incorporation of the transducer impulse response may increase both accuracy and precision of ultrasound transit time spectroscopy. A digital 1 MHz sinusoid signal was used to create an ultrasound pulse that was propagated through a 5 step-wedge acrylic s le immersed in water. Transit time spectra were obtained through deconvolution utilising an ultrasound input signal, along with a digital input signal, with and without incorporation of the transducer impulse response. Incorporation of the transducer impulse response reduced a quantitative measure of noise-to-signal ratio by a factor of 12. The paper has demonstrated the potential for increased accuracy and precision of transit time spectroscopy when the transducer impulse response is incorporated within active-set deconvolution analysis.

Wolffian duct differentiation by physiological concentrations of androgen delivered systemically

Publisher: Elsevier BV

Date: 10-2009

DOI: 10.1016/J.YDBIO.2009.07.040

Abstract: In developing mammalian males, conversion of the Wolffian ducts into the epididymides and vasa deferentia depends on androgen secretion by the testes, whereas in females these ducts remain in a vestigial form or regress. However, there is continuing uncertainty whether the androgen needs to be delivered locally, either by diffusion from the adjacent testis or, by secretion into the lumen of the duct, or whether circulating androgens maintain and virilize the Wolffian ducts. To resolve this uncertainty, we transplanted either day 0-2 or day 8-9 post-partum testes beneath the flank skin of three groups of neonatal (days 0-1) female tammar wallabies, where they developed and secreted physiological levels of hormones. The Wolffian ducts of all these females were retained and had formed extensive epididymides when examined at days 25, 34 and 87 after birth. In the two older groups of females, s led after the time of prostatic bud formation, the urogenital sinus was virilized and there was extensive prostatic development similar to that of normal males of the same age, showing that androgen secretion had occurred. Virilization of the Wolffian ducts occurred during an early but short-lived window of sensitivity. This study provides the first clear evidence that under physiological conditions virilization can be mediated by circulating androgen.

Sex-linked and autosomal microsatellites provide new insights into island populations of the tammar wallaby

Publisher: Springer Science and Business Media LLC

Date: 30-10-2013

DOI: 10.1038/HDY.2013.109

Immunoglobulin G levels in fetal and newborn tammar wallabies (Macropus eugenii)

Publisher: CSIRO Publishing

Date: 1990

DOI: 10.1071/RD9900369

Abstract: Immunoglobulin G (IgG) was measured in fetal, neonatal and colostral s les from the tammar wallaby (Macropus eugenii) in order to study the possibility of passively acquired immunity. S les were obtained from young at a known stage of gestation and at known times (to the minute) after birth. IgG was present (in increasing levels of concentration) in fetal serum, neonatal serum and colostrum. Since the fetus and neonate are probably unable to make immunoglobulin (Ig), it is hypothesized that transplacental and trans-gut transmission takes place from mother to offspring. The vascular yolk sac placenta has a high concentration of IgG, and is the most likely route of transmission from mother to young. Some observations were made of IgA which was found only in colostrum. No Ig of either kind was found in yolk sac fluid.

Mouse embryos used as a bioassay to determine control of marsupial embryonic diapause

Publisher: Wiley

Date: 05-1999

DOI: 10.1002/(SICI)1097-010X(19990501)283:6<590::AID-JEZ11>3.0.CO;2-L

Milk ejection in a marsupial, Macropus agilis

Publisher: Springer Science and Business Media LLC

Date: 02-1981

DOI: 10.1038/289504A0

Embryo—Maternal Interactions after Diapause in a Marsupial

Publisher: Springer New York

Date: 1999

DOI: 10.1007/978-1-4612-1548-6_5

Prostaglandin in the peripheral plasma of tammar wallabies during parturition

Publisher: Bioscientifica

Date: 10-1986

DOI: 10.1677/JOE.0.1110103

Abstract: Tammar wallabies ( Macropus eugenii ) were observed for 7 days, 24 h/day, at the expected time of birth in two consecutive breeding seasons. Blood was collected from the lateral tail vein 1–2 days before birth, then at 10- to 20-min intervals in the peripartum period and less frequently to 30-h post partum. Plasma was assayed for the prostaglandin metabolite 13, 14-dihydro-15-oxo-prostaglandin F 2α (PGFM), progesterone and LH. An assay for PGFM was validated which allows direct measurement in 100 μl unextracted plasma with a sensitivity of 0·14 nmol/l (50 pg/ml). There was a short-lived peak of PGFM immediately before or at birth (7·15 ± 2·52 nmol/l 2536± 892 pg/ml) which declined to less than 0·28 nmol/l (100 pg/ml) within 2-h post partum. Progesterone concentrations declined about the time of birth, coincident with the peak of PGFM, and reached levels observed in lactationally quiescent animals by 16-h post partum , which was also the time of the LH peak. The transient prostaglandin pulse was detected only by frequent s ling and suggests that, as in other mammals, prostaglandin is important in parturition. J. Endocr. (1986) 111, 103–109

Reactivating tammar wallaby blastocysts oxidize fatty acids and amino acids

Publisher: Bioscientifica

Date: 1999

DOI: 10.1530/JRF.0.1150079

Abstract: The tammar wallaby, Macropus eugenii, has a ruminant-like digestive system which may make a significant concentration of amino acids and fatty acids available to the blastocyst via uterine fluids. Fluorescent and radioisotope analyses were performed to determine the rate of glutamine and palmitate use by blastocysts recovered on day 0, 3, 4, 5 and 10 after reactivation induced by removal of pouch young (RPY). Between day 0 and 4 glutamine uptake increased from 15.6 +/- 6.6 to 36.1 +/- 2.7 pmol per embryo h-1 (P < 0.01) and ammonium production increased from 8.2 +/- 4.3 to 26.6 +/- 3.0 pmol per embryo h-1 (P < 0.01). Glutamine oxidation did not increase until day 10 after RPY (P < 0.01), but the percentage of glutamine oxidized increased from 4.5 +/- 3.1% during diapause to 31.2 +/- 12.6% (P < 0.01) by day 5 after RPY and increased further to 51.0 +/- 15.8% (P < 0.01) by day 10 after RPY. Palmitate oxidation also increased from 0.3 +/- 0.1 by day 0 blastocysts to 3.8 +/- 1.7 pmol per embryo h-1 (P < 0.01) by day 4 blastocysts. This increase provides a greater potential for ATP production, possibly to supply increased demand due to the coincident resumption of mitoses. The ATP:ADP ratio within blastocysts had reduced by the time of the first measurement at day 3 (0.5 +/- 0.2 pmol per embryo h-1 P < 0.01) compared with day 0 blastocysts (1.4 +/- 0.3 pmol per embryo h-1). It is likely that metabolism of amino acids and fatty acids contributes to the energy supply during reactivation of tammar wallaby blastocysts after embryonic diapause.

Transcriptomic analysis supports similar functional roles for the two thymuses of the tammar wallaby

Publisher: Springer Science and Business Media LLC

Date: 19-08-2011

DOI: 10.1186/1471-2164-12-420

Abstract: The thymus plays a critical role in the development and maturation of T-cells. Humans have a single thoracic thymus and presence of a second thymus is considered an anomaly. However, many vertebrates have multiple thymuses. The tammar wallaby has two thymuses: a thoracic thymus (typically found in all mammals) and a dominant cervical thymus. Researchers have known about the presence of the two wallaby thymuses since the 1800s, but no genome-wide research has been carried out into possible functional differences between the two thymic tissues. Here, we used pyrosequencing to compare the transcriptomes of a cervical and thoracic thymus from a single 178 day old tammar wallaby. We show that both the tammar thoracic and the cervical thymuses displayed gene expression profiles consistent with roles in T-cell development. Both thymuses expressed genes that mediate distinct phases of T-cells differentiation, including the initial commitment of blood stem cells to the T-lineage, the generation of T-cell receptor ersity and development of thymic epithelial cells. Crucial immune genes, such as chemokines were also present. Comparable patterns of expression of non-coding RNAs were seen. 67 genes differentially expressed between the two thymuses were detected, and the possible significance of these results are discussed. This is the first study comparing the transcriptomes of two thymuses from a single in idual. Our finding supports that both thymuses are functionally equivalent and drive T-cell development. These results are an important first step in the understanding of the genetic processes that govern marsupial immunity, and also allow us to begin to trace the evolution of the mammalian immune system.

A practical and theoretical definition of very small field size for radiotherapy output factor measurements

Publisher: Wiley

Date: 19-03-2014

DOI: 10.1118/1.4868461

Abstract: This work introduces the concept of very small field size. Output factor (OPF) measurements at these field sizes require extremely careful experimental methodology including the measurement of dosimetric field size at the same time as each OPF measurement. Two quantifiable scientific definitions of the threshold of very small field size are presented. A practical definition was established by quantifying the effect that a 1 mm error in field size or detector position had on OPFs and setting acceptable uncertainties on OPF at 1%. Alternatively, for a theoretical definition of very small field size, the OPFs were separated into additional factors to investigate the specific effects of lateral electronic disequilibrium, photon scatter in the phantom, and source occlusion. The dominant effect was established and formed the basis of a theoretical definition of very small fields. Each factor was obtained using Monte Carlo simulations of a Varian iX linear accelerator for various square field sizes of side length from 4 to 100 mm, using a nominal photon energy of 6 MV. According to the practical definition established in this project, field sizes ≤15 mm were considered to be very small for 6 MV beams for maximal field size uncertainties of 1 mm. If the acceptable uncertainty in the OPF was increased from 1.0% to 2.0%, or field size uncertainties are 0.5 mm, field sizes ≤12 mm were considered to be very small. Lateral electronic disequilibrium in the phantom was the dominant cause of change in OPF at very small field sizes. Thus the theoretical definition of very small field size coincided to the field size at which lateral electronic disequilibrium clearly caused a greater change in OPF than any other effects. This was found to occur at field sizes ≤12 mm. Source occlusion also caused a large change in OPF for field sizes ≤8 mm. Based on the results of this study, field sizes ≤12 mm were considered to be theoretically very small for 6 MV beams. Extremely careful experimental methodology including the measurement of dosimetric field size at the same time as output factor measurement for each field size setting and also very precise detector alignment is required at field sizes at least ≤12 mm and more conservatively≤15 mm for 6 MV beams. These recommendations should be applied in addition to all the usual considerations for small field dosimetry, including careful detector selection.

The mammary gland-specific marsupial ELP and eutherian CTI share a common ancestral gene

Publisher: Springer Science and Business Media LLC

Date: 2012

DOI: 10.1186/1471-2148-12-80

Reproduction in the male honey possum (Tarsipes rostratus: Marsupialia): The epididymis

Publisher: Wiley

Date: 11-1986

DOI: 10.1002/AJA.1001770308

Abstract: The epididymis of the adult honey possum, Tarsipes rostratus, is enclosed by a heavily pigmented tunica vaginalis and lies with the testis in a prominent prepenile scrotum. It is connected to the testis by a single ductus efferentis and is lined by approximately equal numbers of cuboidal ciliated and principal cells. It is unusual for marsupials in having no well-defined compartments or fibrous septae and in having extensive convolutions of the duct only at the caudal flexure. Three principal functional zones (initial, middle, and terminal segments) were identified in the epididymis, based on epithelial type and ultrastructural evidence of sperm maturation. Luminal diameter increases progressively throughout the tract, and epithelial height variations (from about 2 to 20 microns) are greatest in the terminal segment. The epithelium itself is remarkably low (maximum of 21.6 microns) compared with that seen in the epididymis of other mammals. The thickness of the peritubular smooth muscle coat increases close to the junction of the epididymis and ductus deferens. Sperm concentrations were estimated from counts of sperm nuclei and thus can be no more than approximations. The figures are consistent, however, with a rapid increase in concentration in the initial segment, indicating extensive fluid resorption. Sperm concentrations appear to peak in the distal zone of the terminal segment, although s ling problems and wide variations in count make such a conclusion only tentative. Principal and basal cells are the predominant cell types in the epididymal epithelium. Basal cells are most abundant in the initial and distal middle segment. Principal cells show structural evidence of active exchange with the luminal contents and have abundant apical stereocilia, the structure of which depends on the epididymal zone. Other cell types occur less commonly in the epithelium. Lipid-rich and phagocytic principal cells are restricted to the middle and distal zones of the middle segment, respectively. Clear cells, restricted to the terminal segment, and halo cells were found in very low numbers. As in some other marsupials, principal cells (possibly specialized for this function) selectively remove cytoplasmic droplets and probably other cellular debris from the luminal contents. In Tarsipes, however, this process is not very efficient, and many discarded droplets pass through to the terminal segment where they form large masses of debris associated with aggregates of degenerating spermatozoa.

Marsupials: alternative mammals

Publisher: Springer Science and Business Media LLC

Date: 09-1981

DOI: 10.1038/293100A0

Marsupials have monoallelic MEST expression with a conserved antisense lncRNA but MEST may not be imprinted.

Publisher: Research Square Platform LLC

Date: 17-02-2023

DOI: 10.21203/RS.3.RS-2577479/V1

Abstract: The imprinted isoform of the Mest gene in mice is involved in key mammalian traits such as placental and fetal growth, maternal care and mammary gland maturation. MEST has a distinct promoter differentially methylated region (DMR) in eutherian mammals but in marsupials, while MEST was thought to be imprinted, it had no DMR. In this study, we examined similarities and differences in the MEST gene locus across mammals using a marsupial, the tammar wallaby, a monotreme, the platypus, and a eutherian, the mouse, to investigate how MEST imprinting evolved in mammals. By confirming the presence of the short isoform in all mammalian groups (which is imprinted in eutherians), this study suggests that an alternative promoter for the short isoform has evolved at the MEST gene locus in the common ancestor of mammals. In the tammar, the short isoform of MEST shared the putative promoter CpG island with an antisense lncRNA previously identified in humans and an isoform of a neighbouring gene CEP41 . The antisense lncRNA was expressed in tammar sperm, as seen in humans. This suggested that the conserved lncRNA might play an important part in the establishment of MEST imprinting in therian mammals, but it was not imprinted in the tammar. In contrast to previous studies, this study showed that MEST is non-imprinted and mono-allelically expressed in marsupials. This suggests that selection of MEST imprinting in eutherians must have occurred after the marsupial-eutherian split with the acquisition of a key epigenetic imprinting control region, the DMR.

Rsx is a metatherian RNA with Xist-like properties in X-chromosome inactivation

Publisher: Springer Science and Business Media LLC

Date: 17-06-2012

DOI: 10.1038/NATURE11171

The history of the discovery of embryonic diapause in mammals

Publisher: Oxford University Press (OUP)

Date: 07-05-2018

DOI: 10.1093/BIOLRE/IOY112

Abstract: The first incidence of embryonic diapause in mammals was observed in the roe deer, Capreolus capreolus, in 1854 and confirmed in the early 1900s. Since then scientists have been fascinated by this phenomenon that allows a growing embryo to become arrested for up to 11 months and then reactivate and continue development with no ill effects. The study of diapause has required unraveling basic reproductive processes we now take for granted and has spanned some of the major checkpoints of reproductive biology from the identification of the sex hormones to the hypothalamic-pituitary axis to microRNA and exosomes. This review will describe the history of diapause from its origins to the current day, including its discovery and efforts to elucidate its mechanisms. It will also attempt to highlight the people involved who were instrumental in progressing this field over the last 160 years. The most recent confirmation of mammalian diapause was in the panda in 2009 and there are still multiple mammals where it has been predicted but not yet confirmed. Furthermore, there are many questions still unanswered which ensure that embryonic diapause will continue to be a topic of research for many years to come. Note that there have recently been several extensive reviews covering the recent advances in embryonic diapause, so they will be mentioned only briefly here. For further information refer to Renfree and Shaw 2014 Fenelon et al 2014 Renfree and Fenelon 2017, and references therein.

Birth of Pouch Young after Artificial Insemination in the Tammar Wallaby (Macropus eugenii)1

Publisher: Oxford University Press (OUP)

Date: 02-2005

DOI: 10.1095/BIOLREPROD.104.033282

Reproduction in males of the feathertail glider Acrobates pygmaeus (Marsupialia)

Publisher: Wiley

Date: 10-1988

DOI: 10.1111/J.1469-7998.1988.TB02428.X

Hormone-responsive genes in the SHH and WNT/β-catenin signaling pathways influence urethral closure and phallus growth†

Publisher: Oxford University Press (OUP)

Date: 14-05-2018

DOI: 10.1093/BIOLRE/IOY117

Abstract: Environmental endocrine disruptors (EEDs) that affect androgen or estrogen activity may disrupt gene regulation during phallus development to cause hypospadias or a masculinized clitoris. We treated developing male tammar wallabies with estrogen and females with androgen from day 20-40 postpartum (pp) during the androgen imprinting window of sensitivity. Estrogen inhibited phallus elongation but had no effect on urethral closure and did not significantly depress testicular androgen synthesis. Androgen treatment in females did not promote phallus elongation but initiated urethral closure. Phalluses were collected for transcriptome sequencing at day 50 pp when they first become sexually dimorphic to examine changes in two signaling pathways, sonic hedgehog (SHH) and wingless-type MMTV integration site family (WNT)/β-catenin. SHH mRNA and β-catenin were predominantly expressed in the urethral epithelium in the tammar phallus, as in eutherian mammals. Estrogen treatment and castration of males induced an upregulation of SHH, while androgen treatment downregulated SHH. These effects appear to be direct since we detected putative estrogen receptor α (ERα) and androgen receptor (AR) binding sites near SHH. WNT5A, like SHH, was downregulated by androgen, while WNT4 was upregulated in female phalluses after androgen treatment. After estrogen treatment, WIF1 and WNT7A were both downregulated in male phalluses. After castration, WNT9A was upregulated. These results suggest that SHH and WNT pathways are regulated by both estrogen and androgen to direct the proliferation and elongation of the phallus during differentiation. Their response to exogenous hormones makes these genes potential targets of EEDs in the etiology of abnormal phallus development including hypospadias.

The influence of estrogen on the developing male marsupial

Publisher: CSIRO Publishing

Date: 2001

DOI: 10.1071/RD00123

Abstract: The genes and hormones involved in gonadal differentiation are highly conserved between eutherians and marsupials, although the timing of the developmental events differs. In marsupials, the testis develops seminiferous cords two days after birth, and the ovaries are not distinguishable until around eight days after birth. Differentiation of the internal genitalia is controlled in marsupials, as in eutherians, by testicular testosterone and MÜllerian inhibiting substance, but differentiation of the scrotum in males and mammary primordia in females is hormone-independent. Since the young are easily accessible in the pouch, it is possible to administer gonadal hormones during the period of sexual differentiation. In both Australian and South American marsupials, estradiol treatment of neonatal males can induce male-to-female gonadal sex reversal. The testicular transformations range from partial suppression of seminiferous tubule development to the development of a morphologically normal ovary depending on the stage that treatment starts. The sex-reversed testes have a clearly defined cortex and medulla, and there are significantly fewer germ cells. The germ cells are surrounded by follicle-like cells and are in the early stages of meiosis, as is normal for XX germ cells in ovaries. In normal males, germ cells only enter meiosis at the onset of puberty. As in eutherians, estrogen treatment of neonatal male marsupials prevents regression of the MÜllerian ducts, which are hypertrophic. Neonatal estradiol exposure also causes hypertrophy of the prostate and urogenital sinus. Estradiol treatment also inhibits transabdominal testicular descent and many animals develop inguinal hernias. The ability of estradiol to cause testis-to-ovary sex reversal in marsupials provides a new way of studying the interactions between genes and hormones in testicular differentiation.

Improvement of B-scan spatial resolution by pulse-echo ultrasound transit time spectroscopy

Publisher: Elsevier BV

Date: 02-2019

DOI: 10.1016/J.APACOUST.2018.10.012

Platypus and echidna genomes reveal mammalian biology and evolution

Publisher: Springer Science and Business Media LLC

Date: 06-01-2021

DOI: 10.1038/S41586-020-03039-0

Abstract: Egg-laying mammals (monotremes) are the only extant mammalian outgroup to therians (marsupial and eutherian animals) and provide key insights into mammalian evolution 1,2 . Here we generate and analyse reference genomes of the platypus ( Ornithorhynchus anatinus ) and echidna ( Tachyglossus aculeatus ), which represent the only two extant monotreme lineages. The nearly complete platypus genome assembly has anchored almost the entire genome onto chromosomes, markedly improving the genome continuity and gene annotation. Together with our echidna sequence, the genomes of the two species allow us to detect the ancestral and lineage-specific genomic changes that shape both monotreme and mammalian evolution. We provide evidence that the monotreme sex chromosome complex originated from an ancestral chromosome ring configuration. The formation of such a unique chromosome complex may have been facilitated by the unusually extensive interactions between the multi-X and multi-Y chromosomes that are shared by the autosomal homologues in humans. Further comparative genomic analyses unravel marked differences between monotremes and therians in haptoglobin genes, lactation genes and chemosensory receptor genes for smell and taste that underlie the ecological adaptation of monotremes.

Kinetics of lower limb prosthesis: Automated detection of vertical loading rate

Publisher: MDPI AG

Date: 29-10-2019

DOI: 10.3390/PROSTHESIS1010004

Abstract: Vertical loading rate could be associated with residuum and whole body injuries affecting in iduals fitted with transtibial prostheses. The objective of this study was to outline one out of five automated methods of extraction of vertical loading rate that stacked up the best against manual detection, which is considered the gold standard during pseudo-prosthetic gait. The load applied on the long axis of the leg of three males was recorded using a transducer fitted between a prosthetic foot and physiotherapy boot while walking on a treadmill for circa 30 min. The automated method of extraction of vertical loading rate, combining the lowest absolute average and range of 95% CI difference compared to the manual method, was deemed the most accurate and precise. The average slope of the loading rate detected manually over 150 strides was 5.56 ± 1.33 kN/s, while the other slopes ranged from 4.43 ± 0.98 kN/s to 6.52 ± 1.64 kN/s depending on the automated detection method. An original method proposed here, relying on progressive loading gradient-based automated extraction, produced the closest results (6%) to manual selection. This work contributes to continuous efforts made by providers of prosthetic and rehabilitation care to generate evidence informing reflective clinical decision-making.

DDX4 (VASA) Is Conserved in Germ Cell Development in Marsupials and Monotremes1

Publisher: Oxford University Press (OUP)

Date: 10-2011

DOI: 10.1095/BIOLREPROD.111.091629

Abstract: DDX4 (VASA) is an RNA helicase expressed in the germ cells of all animals. To gain greater insight into the role of this gene in mammalian germ cell development, we characterized DDX4 in both a marsupial (the tammar wallaby) and a monotreme (the platypus). DDX4 is highly conserved between eutherian, marsupial, and monotreme mammals. DDX4 protein is absent from tammar fetal germ cells but is present from Day 1 postpartum in both sexes. The distribution of DDX4 protein during oogenesis and spermatogenesis in the tammar is similar to eutherians. Female tammar germ cells contain DDX4 protein throughout all stages of postnatal oogenesis. In males, DDX4 is in gonocytes, and during spermatogenesis it is present in spermatocytes and round spermatids. A similar distribution of DDX4 occurs in the platypus during spermatogenesis. There are several DDX4 isoforms in the tammar, resulting from both pre- and posttranslational modifications. DDX4 in marsupials and monotremes has multiple splice variants and polyadenylation motifs. Using in silico analyses of genomic databases, we found that these previously unreported splice variants also occur in eutherians. In addition, several elements implicated in the control of Ddx4 expression in the mouse, including RGG (arginine-glycine-glycine) and dimethylation of arginine motifs and CpG islands within the Ddx4 promoter, are also highly conserved. Collectively these data suggest that DDX4 is essential for the regulation of germ cell proliferation and differentiation across all three extant mammalian groups-eutherians, marsupials, and monotremes.

Evolutionary history of novel genes on the tammar wallaby Y chromosome: Implications for sex chromosome evolution

Publisher: Cold Spring Harbor Laboratory

Date: 29-11-2011

DOI: 10.1101/GR.120790.111

Abstract: We report here the isolation and sequencing of 10 Y-specific tammar wallaby ( Macropus eugenii ) BAC clones, revealing five hitherto undescribed tammar wallaby Y genes (in addition to the five genes already described) and several pseudogenes. Some genes on the wallaby Y display testis-specific expression, but most have low widespread expression. All have partners on the tammar X, along with homologs on the human X. Nonsynonymous and synonymous substitution ratios for nine of the tammar XY gene pairs indicate that they are each under purifying selection. All 10 were also identified as being on the Y in Tasmanian devil ( Sarcophilus harrisii a distantly related Australian marsupial) however, seven have been lost from the human Y. Maximum likelihood phylogenetic analyses of the wallaby YX genes, with respective homologs from other vertebrate representatives, revealed that three marsupial Y genes ( HCFC1X/Y, MECP2X/Y , and HUWE1X/Y ) were members of the ancestral therian pseudoautosomal region (PAR) at the time of the marsupial/eutherian split three XY pairs ( SOX3/SRY, RBMX/Y , and ATRX/Y ) were isolated from each other before the marsupial/eutherian split, and the remaining three ( RPL10X/Y, PHF6X/Y , and UBA1/UBE1Y ) have a more complex evolutionary history. Thus, the small marsupial Y chromosome is surprisingly rich in ancient genes that are retained in at least Australian marsupials and evolved from testis–brain expressed genes on the X.

DNA methylation dynamics in the germline of the marsupial tammar wallaby,Macropus eugenii

Publisher: Oxford University Press (OUP)

Date: 07-12-2018

DOI: 10.1093/DNARES/DSY040

Evolution of Genomic Imprinting: Insights from Marsupials and Monotremes

Publisher: Annual Reviews

Date: 09-2009

DOI: 10.1146/ANNUREV-GENOM-082908-150026

Abstract: Parent-of-origin gene expression (genomic imprinting) is widespread among eutherian mammals and also occurs in marsupials. Most imprinted genes are expressed in the placenta, but the brain is also a favored site. Although imprinting evolved in therian mammals before the marsupial-eutherian split, the mechanisms have continued to evolve in each lineage to produce differences between the two groups in terms of the number and regulation of imprinted genes. As yet there is no evidence for genomic imprinting in the egg-laying monotreme mammals, although these mammals also form a placenta (albeit short-lived) and transfer nutrients from mother to embryo. Therefore, imprinting was not essential for the evolution of the placenta and its importance in nutrient transfer but the elaboration of imprinted genes in marsupials and eutherians is associated with viviparity. Here we review the recent analyses of imprinted gene clusters in marsupials and monotremes, which have served to shed light on the origin and evolution of imprinting mechanisms in mammals.

A Role for Glucocorticoids in Parturition in a Marsupial, Macropus Eugenii1

Publisher: Oxford University Press (OUP)

Date: 03-1996

DOI: 10.1095/BIOLREPROD54.3.728

Abstract: Dexamethasone treatment induces premature birth in tammar wallabies. Treatment was administered at one of three times between 1200 h on Day 24 and 0930 on Day 25, and birth occurred 22.8 +/- 0.5 h later, significantly earlier than the time of birth for controls, which was 47.7 +/- 2.3 h after treatment. The neonates from treated females were significantly lighter than control neonates (360 +/- 9 vs. 413 +/- 5 mg), and 60% of these died within 12 h of birth, suggesting that premature birth can lead to neonatal mortality. None of the control neonates died. The patterns of secretion of prolactin, prostaglandin F2 alpha-metabolite (PGFM), and progesterone of control and treated animals around the time of birth were similar. A transient pulse of PGFM was coincident with birth while prolactin levels in plasma increased before, and progesterone concentrations fell steeply immediately after, parturition in both groups of animals. The only difference between control and treated animals was in the timing of the hormonal events, which, along with birth, was significantly advanced by the treatment. We conclude that cortisol may play a role in triggering parturition in this marsupial species.

Steroids in pregnancy and parturition in the marsupial, Macropus eugenii

Publisher: Elsevier BV

Date: 07-1979

DOI: 10.1016/0022-4731(79)90076-1

Hormone-Independent Pathways of Sexual Differentiation

Publisher: S. Karger AG

Date: 2014

DOI: 10.1159/000358447

Abstract: New observations over the last 25 years of hormone-independent sexual dimorphisms have gradually and unequivocally overturned the dogma, arising from Jost's elegant experiments in the mid-1900s, that all somatic sex dimorphisms in vertebrates arise from the action of gonadal hormones. Although we know that i Sry, /i a Y-linked gene, is the primary gonadal sex determinant in mammals, more recent analysis in marsupials, mice, and finches has highlighted numerous sexual dimorphisms that are evident well before the differentiation of the testis and which cannot be explained by a sexually dimorphic hormonal environment. In marsupials, scrotal bulges and mammary primordia are visible before the testis has differentiated due to the expression of a gene(s) on the X chromosome. ZZ and ZW gynandromorph finches have brains that develop in a sexually dimorphic way dependent on their sex chromosome content. In genetically manipulated mice, it is the X chromosomes, not the gonads, that determine many characters including rate of early development, adiposity, and neural circuits. Even spotted hyenas have sexual dimorphisms that cannot be simply explained by hormonal exposure. This review discusses the recent findings that confirm that there are hormone-independent sexual dimorphisms well before the gonads begin to produce their hormones i . /i

Diapause, pregnancy, and parturition in Australian marsupials

Publisher: Wiley

Date: 08-1993

DOI: 10.1002/JEZ.1402660510

Abstract: Marsupial pregnancy is characterised by a long lactation and a relatively short gestation. Marsupials have, in effect, exchanged the umbilical cord for the teat. However, gestation can be extended for up to 11 months by the imposition of a period of developmental arrest known as embryonic diapause. Diapause may be under either lactational or seasonal control, and in the kangaroos and wallabies these effects are mediated by prolactin and melatonin, respectively. At the other end of gestation, namely parturition, it appears that marsupials are fairly typical mammals and require all the same physiological and behavioural cues essential for the delivery of a viable young. Parturition depends on a synchronised cascade of hormonal events triggered by the fetus itself. Prostaglandin and prolactin concentrations pulse around the time of birth and progesterone falls. Successful parturition also depends on the adoption of the appropriate behaviour and birth posture by the mother. Despite the fact that the entire period of gestation is accomplished in such a short time, the neonate has perfectly adapted its growth and development to influence its mother's physiology to induce the change from nurturing the young in its uterus via a placenta, to a precise synchronisation of the birth process resulting in completion of its growth within the pouch sustained by a milk tailor-made for each developmental stage.

Prostate formation in a marsupial is mediated by the testicular androgen 5α-androstane-3α,17β-diol

Publisher: Proceedings of the National Academy of Sciences

Date: 17-10-2000

DOI: 10.1073/PNAS.220412297

Abstract: Development of the male urogenital tract in mammals is mediated by testicular androgens. It has been tacitly assumed that testosterone acts through its intracellular metabolite dihydrotestosterone (DHT) to mediate this process, but levels of these androgens are not sexually dimorphic in plasma at the time of prostate development. Here we show that the 3α-reduced derivative of DHT, 5α-androstane-3α,17β-diol (5α-adiol), is formed in testes of tammar wallaby pouch young and is higher in male than in female plasma in this species during early sexual differentiation. Administration of 5α-adiol caused formation of prostatic buds in female wallaby pouch young, and in tissue minces of urogenital sinus and urogenital tubercle radioactive 5α-adiol was converted to DHT, suggesting that circulating 5α-adiol acts through DHT in target tissues. We conclude that circulating 5α-adiol is a key hormone in male development.

Retroviral envelope gene captures and syncytin exaptation for placentation in marsupials

Publisher: Proceedings of the National Academy of Sciences

Date: 20-01-2015

DOI: 10.1073/PNAS.1417000112

Abstract: Syncytins are “captured” genes of retroviral origin, corresponding to the fusogenic envelope gene of endogenized retroviruses. They are present in a series of eutherian mammals, including humans and mice where they play an essential role in placentation. Here we show that marsupials—which erged from eutherian mammals ∼190 Mya but still possess a primitive, short-lived placenta (rapidly left by the embryo for development in an external pouch)—have also captured such genes. The present characterization of the syncytin-Opo1 gene in the opossum placenta, together with the identification of two additional endogenous retroviral envelope gene captures, allow a recapitulation of the natural history of these unusual genes and definitely extends their “symbiotic niche” to all clades of placental mammals.

The evolution of class V POU domain transcription factors in vertebrates and their characterisation in a marsupial

Publisher: Elsevier BV

Date: 2010

DOI: 10.1016/J.YDBIO.2009.10.017

Abstract: POU5F1 (OCT4) encodes a master regulator of pluripotency that is present in all mammals. A paralogue, POU2, is also present in the genomes of marsupials and monotremes and is an orthologue of zebrafish pou2 and chicken POUV. We explored the evolution of class V POU domain transcription factors and show that POU5F1 arose by gene duplication of pou2 early in the evolution of tetrapods and is not mammal-specific, as previously thought. Instead, either POU5F1 or POU2/POUV has become extinct independently in various lineages, although all gnathostomes appear to possess at least one or the other. In the tammar wallaby, POU5F1 expression is limited to pluripotent cell types (embryonic tissues and germ cells). POU2 is similarly expressed in pluripotent tissues but is also expressed in a broad range of adult tissues. Thus, unlike POU5F1, the role of POU2 may not be restricted to pluripotent cell types but could have a related function such as maintaining multipotency in adult stem cells.

Effects of a gonadotropin-releasing hormone agonist implant on reproduction in a male marsupial, Macropus eugenii

Publisher: Oxford University Press (OUP)

Date: 06-2004

DOI: 10.1095/BIOLREPROD.103.025122

The influence of Monte Carlo source parameters on detector design and dose perturbation in small field dosimetry

Publisher: IOP Publishing

Date: 24-03-2014

DOI: 10.1088/1742-6596/489/1/012006

The Unique Penile Morphology of the Short-Beaked Echidna, Tachyglossus aculeatus

Publisher: S. Karger AG

Date: 2021

DOI: 10.1159/000515145

Abstract: Monotremes erged from therian mammal ancestors approximately 184 million years ago and have a number of novel reproductive characteristics. One in particular is their penile morphology. There are differences between echidna and platypus phalluses, but both are somewhat similar in structure to the reptilian phallus. The echidna penis consists of 4 rosette glans, each of which contains a termination of the quadrifurcate urethra, but it appears that only 2 of the 4 glans become erect at any one time. Despite this, only a few historical references describe the structure of the echidna penis and none provides an explanation for the mechanisms of unilateral ejaculation. This study confirmed that the echidna penis contains many of the same overall structures and morphology as other mammalian penises and a number of features homologous with reptiles. The corpus cavernosum is well supplied with blood, extends up to the base of the glans penis and is primarily responsible for erection. However, the echidna possesses 2 distinct corpora spongiosa separated by a septum, each of which surround the urethra only distal to the initial urethral bifurcation in the glans penis. Together with the bifurcation of the main penile artery, this provides a mechanism by which blood flow could be directed to only one corpus spongiosum at a time to maintain an open urethra that supplies 2 of the 4 glans to facilitate unilateral ejaculation.

Comparison of active-set method deconvolution and matched-filtering for derivation of an ultrasound transit time spectrum

Publisher: IOP Publishing

Date: 05-06-2015

DOI: 10.1088/0031-9155/60/12/N251

Virilization of the Male Pouch Young of the Tammar Wallaby Does Not Appear to be Mediated by Plasma Testosterone or Dihydrotestosterone1

Publisher: Oxford University Press (OUP)

Date: 08-1999

DOI: 10.1095/BIOLREPROD61.2.471

Abstract: Virilization of the male urogenital tract of all mammals, including marsupials, is mediated by androgenic hormones secreted by the testes. We have previously demonstrated profound sexual dimorphism in the concentrations of gonadal androgens in pouch young of the tammar wallaby Macropus eugenii during the interval when the urogenital sinus virilizes. To provide insight into the mechanisms by which androgens are transported from the testes to the target tissues, we measured testosterone and dihydrotestosterone in plasma pools from tammar pouch young from the day of birth to Day 150. Plasma testosterone levels were measurable (0.5-2 ng/ml) at all times studied, but there were no differences between males and females. These low concentrations of plasma testosterone appear to be derived from the adrenal glands and not the testes. Plasma dihydrotestosterone levels in plasma pools from these animals were also low and not sexually dimorphic. We conclude that virilization of the male urogenital tract cannot be explained by the usual transport of testosterone or dihydrotestosterone in plasma but may be mediated by the direct delivery of androgens to the urogenital tract via the Wolffian ducts. Alternatively, circulating prohormones may be converted to androgens in target tissues.

Preface

Publisher: S. Karger AG

Date: 2015

DOI: 10.1159/000371406

Identification of a Novel PNMA-MS1 Gene in Marsupials Suggests the LTR Retrotransposon-Derived PNMA Genes Evolved Differently in Marsupials and Eutherians

Publisher: Oxford University Press (OUP)

Date: 23-05-2013

DOI: 10.1093/DNARES/DST020

Sexual development of a model marsupial male

Publisher: CSIRO Publishing

Date: 2006

DOI: 10.1071/ZO05057

Abstract: In eutherian mammals sexual differentiation occurs during fetal development, making experimental manipulation difficult, unlike in marsupials. We are investigating the roles of several key genes and hormones whose exact role in gonadal differentiation is still unclear using the tammar wallaby (Macropus eugenii) as a model. As in humans, unlike in mice, the testis-determining gene SRY is expressed in male tammar fetuses in many tissues over an extended period. Not all sexual differentiation depends on testicular hormones. Scrotum and mammary glands are under the control of X-linked gene(s). Our demonstration of DMRT1 expression in tammar and mouse ovaries suggests it has a wider role than previously thought. The Y-borne copy of ATRX (ATRY) is coexpressed with DMRT1 in developing testis. Gonadal sex reversal can be induced in males by neonatal oestrogen treatment and in females by grafting developing ovaries to males or culturing them in minimal medium. Treatments of developing young with various androgens, and studies of steroid metabolism have shown that the steroid androstenediol may have a previously unrecognised role in virilisation. Our studies using a marsupial model have given some surprising insights into the evolution and control of sexual development in all mammals.

Lung Development of Monotremes: Evidence for the Mammalian Morphotype

Publisher: Wiley

Date: 02-12-2008

DOI: 10.1002/AR.20825

Abstract: The reproductive strategies and the extent of development of neonates differ markedly between the three extant mammalian groups: the Monotremata, Marsupialia, and Eutheria. Monotremes and marsupials produce highly altricial offspring whereas the neonates of eutherian mammals range from altricial to precocial. The ability of the newborn mammal to leave the environment in which it developed depends highly on the degree of maturation of the cardio-respiratory system at the time of birth. The lung structure is thus a reflection of the metabolic capacity of neonates. The lung development in monotremes (Ornithorhynchus anatinus, Tachyglossus aculeatus), in one marsupial (Monodelphis domestica), and one altricial eutherian (Suncus murinus) species was examined. The results and additional data from the literature were integrated into a morphotype reconstruction of the lung structure of the mammalian neonate. The lung parenchyma of monotremes and marsupials was at the early terminal air sac stage at birth, with large terminal air sacs. The lung developed slowly. In contrast, altricial eutherian neonates had more advanced lungs at the late terminal air sac stage and postnatally, lung maturation proceeded rapidly. The mammalian lung is highly conserved in many respects between monotreme, marsupial, and eutherian species and the structural differences in the neonatal lungs can be explained mainly by different developmental rates. The lung structure of newborn marsupials and monotremes thus resembles the ancestral condition of the mammalian lung at birth, whereas the eutherian newborns have a more mature lung structure.

A CAD interface for GEANT4

Publisher: Springer Science and Business Media LLC

Date: 09-2012

DOI: 10.1007/S13246-012-0159-8

Abstract: Often CAD models already exist for parts of a geometry being simulated using GEANT4. Direct import of these CAD models into GEANT4 however, may not be possible and complex components may be difficult to define via other means. Solutions that allow for users to work around the limited support in the GEANT4 toolkit for loading predefined CAD geometries have been presented by others, however these solutions require intermediate file format conversion using commercial software. Here within we describe a technique that allows for CAD models to be directly loaded as geometry without the need for commercial software and intermediate file format conversion. Robustness of the interface was tested using a set of CAD models of various complexity for the models used in testing, no import errors were reported and all geometry was found to be navigable by GEANT4.

A 3D-printed phantom twin and multi-transducer holder for dynamic anatomical ultrasonography of the lower limb

Publisher: Future Medicine Ltd

Date: 06-2023

DOI: 10.2217/3DP-2023-0004

Abstract: We aim to improve the residuum health of in iduals suffering from lower-limb loss through ‘digital twin’ computational simulations for the creation of optimized 3D-printed prosthetic attachments. Our objective is to utilize 4D tracking data of various tissue interfaces as a primary input into the digital twin. Dynamic anatomical ultrasonography (DAU) is a novel technique in which synchronized in idual transducers are positioned at known locations utilizing a 3D-printed holder. Pulse-echo ultrasound data are recorded and subsequently analyzed, providing plots of tissue interface depths versus recording time. For the scientific validation of the DAU technique, a bespoke 3D-printed phantom twin has been created incorporating replica compartments of soft-tissue interfaces and bone tissue of a healthy thigh. To demonstrate its utility, a preliminary experiment was performed in which the phantom twin was positioned within the DAU device and the replica bone manually traversed randomly subsequent DAU analysis provided a plot of interface depth versus recording time.

Mating sequence, dominance and paternity success in captive male tammar wallabies

Publisher: Bioscientifica

Date: 07-2005

DOI: 10.1530/REP.1.00624

Abstract: The tammar wallaby ( Macropus eugenii ) is a small, promiscuous, macropodid marsupial. Females usually produce a single young each year and there is a clear dominance hierarchy between adult males. The dominant male usually mates first and then guards the female to prevent access to her by other males. In this study, agonistic encounters and mating behaviour were observed to determine male dominance hierarchies in six groups of captive tammars consisting of a total of 23 males and 50 females. Mating behaviour was observed immediately post-partum when females were in oestrus and was correlated with plasma testosterone concentrations. Male mating sequences were recorded, and the paternity of offspring was determined by using seven macropodid marsupial microsatellites. Rates of sexual checking and aggression by males housed with females in oestrus in the non-breeding season were lower than in the breeding season. These males also had lower concentrations of testosterone, but were still able to sire young. High testosterone concentrations neither ensured dominance nor appeared to control directly the level of sexual activity. Females usually mated with more than one male. The dominant male most often secured the initial copulation (60%), but the first-mating male did not always secure parentage, with second and third matings resulting in as many young as first matings. Using these data, we were unable to discount first sire, last sire or equal chance models of paternity in this species. Half the young (50%) were sired by the dominant α male, but of the remaining progeny, the β male sired more (35%) than γ and δ males (15%). Dominance therefore is only a moderately effective predictor of paternity in the tammar. Although the dominant males gained most first matings and in idually sired half of the offspring, the subdominant males still contributed significantly to the population, at least in captivity.

Characterization of steroidogenic factor 1 during sexual differentiation in a marsupial

Publisher: Elsevier BV

Date: 10-2001

DOI: 10.1016/S0378-1119(01)00677-1

Abstract: In eutherian mammals, such as mice and humans, steroidogenic factor 1 (SF1) plays important roles in the development of the gonad and in its steroidogenic activity. Marsupial and eutherian mammals have been evolving independently for at least 100 million years and so we were interested in comparing SF1 of a marsupial with that of eutherians. To this end, we have cloned SF1 from an Australian marsupial, the tammar wallaby. Although the amino acid sequence of SF1 is highly conserved among vertebrate species, tammar SF1 appears to have erged less from the ancestral SF1 than have eutherian SF1 proteins. Tammar SF1 is expressed by both ovaries and testes on the day of birth, just prior to the onset of testicular differentiation, until at least 8 days after birth by which time the ovary also has begun to sexually differentiate. SF1 transcripts are localized predominantly to the pre-granulosa and Sertoli cells of the ovary and testis, respectively. In the testis SF1 transcripts are also present in the interstitial cells, although at a lower level than that which is observed in the Sertoli cells. SF1 is also transcribed in adult testis and ovary. In the adult ovary SF1 is expressed in the interstitial gland, and in the granulosa cells and theca interna of small to medium-sized antral follicles, but is not expressed in large antral follicles. Thus, although the structure of tammar SF1 is ergent from that of eutherians, its expression profile is similar, supporting a conserved role in gonadal development and steroidogenesis.

Development of the penis and clitoris in the tammar wallaby, Macropus eugenii

Publisher: Springer Science and Business Media LLC

Date: 19-03-1999

DOI: 10.1007/S004290050243

Abstract: The development of the phallus from the indifferent stage to sexual dimorphism has not been described in any marsupial. This study describes the morphological and histological changes occurring in the development of the phallus of the tammar wallaby. The development of the penis and clitoris in the tammar closely follow the most widely accepted model for the development of the same organs in eutherian mammals. The urogenital plate that is present in both sexes at birth hollows out to form a urogenital groove at approximately 70 days postpartum (p.p.). There is then greater growth of the phallus in males than in females, which results in sexual dimorphism in length approximately 100 days p.p. In males, the urogenital groove secondarily closes over at this time and fuses in the midline and by 128 days p.p. the penile urethra is fully formed. In females, the groove remains open. The clitoris changes little morphologically from the time of formation of the urogenital groove until adulthood. The pattern of development of the penis in the tammar is similar to that seen in eutherian mammals. There is strong evidence that penis development is androgen-dependent in the tammar, yet unusually it becomes sexually dimorphic at a time when androgen content of the developing testis is low.

The developing renal, reproductive, and respiratory systems of the African elephant suggest an aquatic ancestry

Publisher: Proceedings of the National Academy of Sciences

Date: 11-05-1999

DOI: 10.1073/PNAS.96.10.5555

Abstract: The early embryology of the elephant has never been studied before. We have obtained a rare series of African elephant ( Loxodonta africana ) embryos and fetuses ranging in weight from 0.04 to 18.5 g, estimated gestational ages 58–166 days (duration of gestation is ≈660 days). Nephrostomes, a feature of aquatic vertebrates, were found in the mesonephric kidneys at all stages of development whereas they have never been recorded in the mesonephric kidneys of other viviparous mammals. The trunk was well developed even in the earliest fetus. The testes were intra-abdominal, and there was no evidence of a gubernaculum, p iniform plexus, processus vaginalis, or a scrotum, confirming that the elephant, like the dugong, is one of the few primary testicond mammals. The palaeontological evidence suggests that the elephant’s ancestors were aquatic, and recent immunological and molecular evidence shows an extremely close affinity between present-day elephants and the aquatic Sirenia (dugong and manatees). The evidence from our embryological study of the elephant also suggests that it evolved from an aquatic mammal.

Diapause

Publisher: Annual Reviews

Date: 03-2000

DOI: 10.1146/ANNUREV.PHYSIOL.62.1.353

Abstract: ▪ Abstract Embryonic diapause, or delayed implantation as it is sometimes known, is said to occur when the conceptus enters a state of suspended animation at the blastocyst stage of development. Blastocysts may either cease cell ision so that their size and cell numbers remain constant, or undergo a period of very slow growth with minimal cell ision and expansion. Diapause has independently evolved on many occasions. There are almost 100 mammals in seven different mammalian orders that undergo diapause. In some groups, such as rodents, kangaroos, and mustelids, it is widespread, whereas others such as the Artiodactyla have only a single representative (the roe deer). In each family the characteristics of diapause differ, and the specific controls vary widely from lactational to seasonal, from estrogen to progesterone, or from photoperiod to nutritional. Prolactin is a key hormone controlling the endocrine milieu of diapause in many species, but paradoxically it may act either to stimulate or inhibit growth and activity of the corpus luteum. Whatever the speciesspecific mechanisms, the ecological result of diapause is one of synchronization: It effectively lengthens the active gestation period, which allows mating to occur and young to be born at times of the year optimal for that species.

Contraceptive effects of extended lactational amenorrhoea: beyond the Bellagio Consensus

Publisher: Elsevier BV

Date: 03-1991

DOI: 10.1016/0140-6736(91)90288-Z

Abstract: We have recorded the duration of lactational anovulation and amenorrhoea in a well-nourished group of Australian women who breastfed their babies throughout the study. The data enabled us to compare the theoretical cumulative probability of conception among breastfeeding women who had unprotected intercourse irrespective of their menstrual status with that of those who had unprotected intercourse only during lactational amenorrhoea. Breastfeeding alone is not an effective form of contraception, since all the women in our study resumed normal ovulation while still breastfeeding. However, among women who have unprotected intercourse only during lactational amenorrhoea but adopt other contraceptive measures when they resume menstruation, only 1.7% would have become pregnant during the first 6 months of amenorrhoea, only 7% after 12 months, and only 13% after 24 months. Thus for our women it would be possible to extend the Bellagio Consensus Conference guidelines which stated that lactational amenorrhoea can only be relied on as a contraceptive for the first 6 months post-partum in women who are fully or almost fully breastfeeding. The lactational amenorrhoea method can be relied on for excellent contraceptive protection in the first 6 months of breastfeeding, irrespective of when supplements are introduced into the baby's diet for women who continue to breastfeed the method can also give good protection for up to 12 months post partum. Once menstruation has returned, other forms of contraception are essential to prevent pregnancy.

The Comparative Physiology of Parturition in Mammals: Hormones and Parturition in Mammals

Publisher: Elsevier

Date: 2011

DOI: 10.1016/B978-0-12-374928-4.10006-9

In memoriam Anne McLaren

Publisher: UPV/EHU Press

Date: 2008

DOI: 10.1387/IJDB.072494MR

Whole-mount immunohistochemical staining of tammar wallaby (Macropus eugenii) peri-gastrulation embryos

Publisher: Cold Spring Harbor Laboratory

Date: 12-2009

DOI: 10.1101/PDB.PROT5340

Abstract: This protocol describes a method for whole-mount immunohistochemical staining of tammar wallaby ( Macropus eugenii ) peri-gastrulation stage embryos using the avidin-biotin complex system. Tammar embryos are ideal for whole-mount immunostaining because of their morphology: They develop in a planar manner on the surface of the embryonic vesicle and are not covered by any extraembryonic membranes until amnion formation (which occurs during mid-somitogenesis). Tammar embryos are surrounded by a transparent shell coat, which must be opened prior to staining to ensure penetration of solutions and reagents.

The olfactory system of the tammar wallaby is developed at birth and directs the neonate to its mother's pouch odours

Publisher: Bioscientifica

Date: 11-2009

DOI: 10.1530/REP-09-0145

Abstract: In kangaroos and wallabies at birth the highly altricial newborn young climbs unassisted from the urogenital opening to the teat. Negative geotropism is important for the initial climb to the pouch opening, but nothing is known of the signals that then direct the neonate downwards to the teat. Here we show that the newborn tammar wallaby ( Macropus eugenii ) has the olfactory apparatus to detect smell. Both the main olfactory system and vomeronasal organ (VNO) are developed at the time of birth. Receptor cells of the main olfactory epithelium immunopositive for G oα -protein project to the three layered main olfactory bulb (MOB). The receptor epithelium of the VNO contains G-protein immunopositive cells and has olfactory knob-like structures. The VNO is connected to an area between the two MOBs. Next, using a functional test, we show that neonates can respond to odours from their mother's pouch. When neonatal young are presented with a choice of a pouch-odour-soaked swab or a saline swab, they choose the swab with their mother's pouch secretions significantly more often ( P .05) than the saline swab. We conclude that both olfactory systems are capable of receiving odour signals at birth, a function that must be a critical adaptation for the survival of an altricial marsupial neonate such as the tammar for its journey to the pouch.

Evolution of the Short Form of DNMT3A, DNMT3A2, Occurred in the Common Ancestor of Mammals

Publisher: Oxford University Press (OUP)

Date: 23-06-2022

DOI: 10.1093/GBE/EVAC094

Abstract: Genomic imprinting is found in marsupial and eutherian mammals, but not in monotremes. While the primary regulator of genomic imprinting in eutherians is differential DNA methylation between parental alleles, conserved imprinted genes in marsupials tend to lack DNA methylation at their promoters. DNA methylation at eutherian imprinted genes is mainly catalyzed by a DNA methyltransferase (DNMT) enzyme, DNMT3A. There are two isoforms of eutherian DNMT3A: DNMT3A and DNMT3A2. DNMT3A2 is the primary isoform for establishing DNA methylation at eutherian imprinted genes and is essential for eutherian genomic imprinting. In this study, we investigated whether DNMT3A2 is also present in the two other mammalian lineages, marsupials and monotremes. We identified DNMT3A2 in both marsupials and monotremes, although imprinting has not been identified in monotremes. By analyzing genomic sequences and transcriptome data across vertebrates, we concluded that the evolution of DNMT3A2 occurred in the common ancestor of mammals. In addition, DNMT3A/3A2 gene and protein expression during gametogenesis showed distinct sexual dimorphisms in a marsupial, the tammar wallaby, and this pattern coincided with the sex-specific DNA methylation reprogramming in this species as it does in mice. Our results show that DNMT3A2 is present in all mammalian groups and suggests that the basic DNMT3A/3A2-based DNA methylation mechanism is conserved at least in therian mammals.

Solid volume fraction estimation of bone:marrow replica models using ultrasound transit time spectroscopy.

Publisher: Elsevier BV

Date: 02-2016

DOI: 10.1016/J.ULTRAS.2015.09.009

Abstract: The acceptance of broadband ultrasound attenuation (BUA) for the assessment of osteoporosis suffers from a limited understanding of both ultrasound wave propagation through cancellous bone and its exact dependence upon the material and structural properties. It has recently been proposed that ultrasound wave propagation in cancellous bone may be described by a concept of parallel sonic rays the transit time of each ray defined by the proportion of bone and marrow propagated. A Transit Time Spectrum (TTS) describes the proportion of sonic rays having a particular transit time, effectively describing the lateral inhomogeneity of transit times over the surface aperture of the receive ultrasound transducer. The aim of this study was to test the hypothesis that the solid volume fraction (SVF) of simplified bone:marrow replica models may be reliably estimated from the corresponding ultrasound transit time spectrum. Transit time spectra were derived via digital deconvolution of the experimentally measured input and output ultrasonic signals, and compared to predicted TTS based on the parallel sonic ray concept, demonstrating agreement in both position and litude of spectral peaks. Solid volume fraction was calculated from the TTS agreement between true (geometric calculation) with predicted (computer simulation) and experimentally-derived values were R(2)=99.9% and R(2)=97.3% respectively. It is therefore envisaged that ultrasound transit time spectroscopy (UTTS) offers the potential to reliably estimate bone mineral density and hence the established T-score parameter for clinical osteoporosis assessment.

Developmental profile of thyroid hormone distributor proteins in a marsupial, the tammar wallaby Macropus eugenii

Publisher: Elsevier BV

Date: 2002

DOI: 10.1006/GCEN.2001.7729

Analysis of the platypus genome suggests a transposon origin for mammalian imprinting

Publisher: Springer Science and Business Media LLC

Date: 2009

DOI: 10.1186/GB-2009-10-1-R1

Genetic sex test for the short-beaked echidna (Tachyglossus aculeatus)

Publisher: Springer Science and Business Media LLC

Date: 30-04-2022

DOI: 10.1007/S12686-022-01258-3

Unique reproductive strategy in the swamp wallaby

Publisher: Proceedings of the National Academy of Sciences

Date: 02-03-2020

DOI: 10.1073/PNAS.1922678117

Abstract: We have shown that female sw wallabies ovulate, mate, and form a new embryo prepartum thereby continuously supporting conceptuses and young at different development stages before and after birth. This system is unique compared to the normal staged system of reproduction in mammals so that sw wallabies are normally pregnant and lactating throughout their reproductive life.

ATRX has a critical and conserved role in mammalian sexual differentiation

Publisher: Springer Science and Business Media LLC

Date: 14-06-2011

DOI: 10.1186/1471-213X-11-39

Abstract: X-linked alpha thalassemia, mental retardation syndrome in humans is a rare recessive disorder caused by mutations in the ATRX gene. The disease is characterised by severe mental retardation, mild alpha-thalassemia, microcephaly, short stature, facial, skeletal, genital and gonadal abnormalities. We examined the expression of ATRX and ATRY during early development and gonadogenesis in two distantly related mammals: the tammar wallaby (a marsupial) and the mouse (a eutherian). This is the first examination of ATRX and ATRY in the developing mammalian gonad and fetus. ATRX and ATRY were strongly expressed in the developing male and female gonad respectively, of both species. In testes, ATRY expression was detected in the Sertoli cells, germ cells and some interstitial cells. In the developing ovaries, ATRX was initially restricted to the germ cells, but was present in the granulosa cells of mature ovaries from the primary follicle stage onwards and in the corpus luteum. ATRX mRNA expression was also examined outside the gonad in both mouse and tammar wallaby whole embryos. ATRX was detected in the developing limbs, craniofacial elements, neural tissues, tail and phallus. These sites correspond with developmental deficiencies displayed by ATR-X patients. There is a complex expression pattern throughout development in both mammals, consistent with many of the observed ATR-X syndrome phenotypes in humans. The distribution of ATRX mRNA and protein in the gonads was highly conserved between the tammar and the mouse. The expression profile within the germ cells and somatic cells strikingly overlaps with that of DMRT1, suggesting a possible link between these two genes in gonadal development. Taken together, these data suggest that ATRX has a critical and conserved role in normal development of the testis and ovary in both the somatic and germ cells, and that its broad roles in early mammalian development and gonadal function have remained unchanged for over 148 million years of mammalian evolution.

Comparative analysis of the mammalian WNT4 promoter

Publisher: Springer Science and Business Media LLC

Date: 06-09-2009

DOI: 10.1186/1471-2164-10-416

Abstract: WNT4 is a critical signalling molecule in embryogenesis and homeostasis, but the elements that control its transcriptional regulation are largely unknown. This study uses comparative cross species sequence and functional analyses between humans and a marsupial (the tammar wallaby, Macropus eugenii ) to refine the mammalian Wnt4 promoter. We have defined a highly conserved 89 bp minimal promoter region in human WNT4 by comparative analysis with the tammar wallaby. There are many conserved transcription factor binding sites in the proximal promoter region, including SP1, MyoD, NFκB and AP2, as well as highly conserved CpG islands within the human, mouse and marsupial promoters, suggesting that DNA methylation may play an important role in WNT4 transcriptional regulation. Using a marsupial model, we have been able to provide new information on the transcriptional regulators in the promoter of this essential mammalian developmental gene, WNT4 . These transcription factor binding sites and CpG islands are highly conserved in two disparate mammals, and are likely key controlling elements in the regulation of this essential developmental gene.

Role of the alternate pathway of dihydrotestosterone formation in virilization of the Wolffian ducts of the tammar wallaby, Macropus eugenii

Publisher: The Endocrine Society

Date: 05-2006

DOI: 10.1210/EN.2005-1251

Abstract: Dihydrotestosterone in androgen target tissues is formed under most circumstances by the 5alpha-reduction of testosterone, but an alternate pathway involves the oxidation of androstanediol to dihydrotestosterone. To investigate the mechanism by which androgens virilize the Wolffian ducts in the tammar wallaby, [(3)H]progesterone was incubated with testes from d 10 and 19 pouch young, and radioactivity was recovered in testosterone and androstanediol at both ages. Analysis of the intermediates indicates that androstanediol was formed both from testosterone via 5alpha-reduction and 3alpha-keto reduction and directly from 5alpha-reduced progestogens. 5alpha-Reductase activity was high in minces of mesonephros/epididymis from d 6-21 pouch young. When minces of urogenital tract tissues from d 19 pouch young were incubated with [(3)H]testosterone, [(3)H]dihydrotestosterone, and [(3)H]androstanediol, dihydrotestosterone was the principal androgen formed in the mesonephros/epididymis, urogenital sinus, and urogenital tubercle, whereas androstanediol was the principal androgen formed by the testis. In intact pouch young studied between d 10 and 34, administration of the 5alpha-reductase inhibitor, 17beta-(N,N-diethyl)carbamoyl-4-methyl-4-aza-5alpha-androstan-3-one, blocked virilization of the Wolffian ducts in males, and administration of androstanediol caused virilization of the Wolffian ducts in females. We conclude that dihydrotestosterone, largely formed in the tissue by the oxidation of androstanediol derived from the testes and also the 5alpha-reduction of testosterone, is responsible for Wolffian duct virilization in this species.

Insulin is imprinted in the placenta of the marsupial, Macropus eugenii

Publisher: Elsevier BV

Date: 09-2007

DOI: 10.1016/J.YDBIO.2007.07.025

Abstract: Therian mammals (marsupials and eutherians) rely on a placenta for embryo survival. All mammals have a yolk sac, but while both chorio-allantoic and chorio-vitelline (yolk sac) placentation can occur, most marsupials only develop a yolk sac placenta. Insulin (INS) is unusual in that it is the only gene that is imprinted exclusively in the yolk sac placenta. Marsupials, therefore, provide a unique opportunity to examine the conservation of INS imprinting in mammalian yolk sac placentation. Marsupial INS was cloned and its imprint status in the yolk sac placenta of the tammar wallaby, Macropus eugenii, examined. In two informative in iduals of the eight that showed imprinting, INS was paternally expressed. INS protein was restricted to the yolk sac endoderm, while insulin receptor, IR, protein was additionally expressed in the trophoblast. INS protein increased during late gestation up to 2 days before birth, but was low the day before and on the day of birth. The conservation of imprinted expression of insulin in the yolk sac placenta of ergent mammalian species suggests that it is of critical importance in the yolk sac placenta. The restriction of imprinting to the yolk sac suggests that imprinting of INS evolved in the chorio-vitelline placenta independently of other tissues in the therian ancestor of marsupials and eutherians.

Penile Development Is Initiated in the Tammar Wallaby Pouch Young during the Period when 5α-Androstane-3α,17β-Diol Is Secreted by the Testes

Publisher: The Endocrine Society

Date: 07-2004

DOI: 10.1210/EN.2004-0150

Abstract: Virilization of the urogenital tract is under the control of testicular androgens in all mammals. In tammar young, prostate differentiation begins between d 20 and d 40 under the control of the testicular androgen 5α-androstane-3α,17β-diol (5α-adiol), but uncertainties exist about the control of penile development. We performed longitudinal studies up to d 150 of pouch life to define normal penile development and the effects of androgen administration and castration. In control animals the male phallus was longer than the female phallus by d 48. Closure of the urethra in males begins around d 60 and continues to at least d 150. Administration of supraphysiological doses of testosterone to females caused penile development equivalent to that of the male and also induced partial closure of the urethral groove by d 150. Castration of male pouch young at d 25 prevented penile development, whereas the penis in males castrated at d 40, 80, or 120 had partial closure of the urethral groove. Administration of 5α-adiol to females from d 20–40 also caused partial closure of the urethral groove and some growth of the phallus at d 150, whereas 5α-adiol treatment from d 40–80 or 80–120 caused some penile growth but had little effect on urethral development. These findings, together with the fact that we found no sex differences in plasma levels of testosterone, dihydrotestosterone, 5α-adiol, dehydroepiandrosterone, or androstenedione from d 51–227, clearly indicate that the action of 5α-adiol between d 20 and 40 imprints later differentiation of the male penis.

In vitro culture of peri‐gastrulation embryos of a macropodid marsupial

Publisher: Wiley

Date: 31-01-2008

DOI: 10.1111/J.1469-7580.2007.00846.X

The Evolution of Mammalian Genomic Imprinting Was Accompanied by the Acquisition of Novel CpG Islands

Publisher: Oxford University Press (OUP)

Date: 2011

DOI: 10.1093/GBE/EVR104

DAX1/NR0B1 Was Expressed During Mammalian Gonadal Development and Gametogenesis Before It Was Recruited to the Eutherian X Chromosome1

Publisher: Oxford University Press (OUP)

Date: 2015

DOI: 10.1095/BIOLREPROD.114.119362

Abstract: The nuclear receptor subfamily 0, group B, member 1 (NR0B1) gene is an orphan nuclear receptor that is X-linked in eutherian mammals and plays a critical role in the establishment and function of the hypothalamic-pituitary-adrenal-gonadal axis. Duplication or overexpression of NR0B1 in eutherian males causes male to female sex reversal, and mutation and deletions of NR0B1 cause testicular defects. Thus, gene dosage is critical for the function of NR0B1 in normal gonadogenesis. However, NR0B1 is autosomal in all noneutherian vertebrates, including marsupials and monotreme mammals, and two active copies of the gene are compatible with both male and female gonadal development. In the current study, we examined the evolution and expression of autosomal NR0B1 during gonadal development in a marsupial (the tammar wallaby) as compared to the role of its X-linked orthologues in a eutherian (the mouse). We show that NR0B1 underwent rapid evolutionary change when it relocated from its autosomal position in the nonmammalian vertebrates, monotremes, and marsupials to an X-linked location in eutherian mammals. Despite the acquisition of a novel genomic location and a unique N-terminal domain, NR0B1 protein distribution was remarkably similar between mice and marsupials both throughout gonadal development and during gamete formation. A conserved accumulation of NR0B1 protein was observed in developing oocytes, where its function appears to be critical in the early embryo, prior to zygotic genome activation. Together these findings suggest that NR0B1 had a conserved role in gonadogenesis that existed long before it moved to the X chromosome and despite undergoing significant evolutionary change.

Genome analysis of the platypus reveals unique signatures of evolution

Publisher: Springer Science and Business Media LLC

Date: 05-2008

DOI: 10.1038/NATURE06936

Virilization of the urogenital sinus of the tammar wallaby is not unique to 5α-androstane-3α,17β-diol

Publisher: Elsevier BV

Date: 07-2001

DOI: 10.1016/S0303-7207(01)00527-5

Abstract: The androgen 5alpha-androstane-3alpha,17beta-diol (5alpha-adiol) is synthesized in testes and secreted into plasma of male tammar wallaby pouch young and appears to virilize the urogenital sinus. To provide insight into its mechanism of action, a dose response study showed that administration of 1 microg 5alpha-adiol monoenanthate per g body wt. per week for 3 weeks to 24-day-old female pouch young induced prostate bud formation equivalent to that of males of the same age. Administration of this same dose of the enanthates of testosterone, dihydrotestosterone, and 5alpha-adiol to female pouch young caused equivalent virilization of the urogenital sinus. The fact that 5alpha-adiol does not exert a unique effect, together with our earlier findings in this species that 5alpha-adiol and testosterone are converted to dihydrotestosterone in the urogenital sinus and that virilization of the urogenital sinus is prevented by the androgen receptor antagonist flutamide, suggest that 5alpha-adiol is a circulating precursor for dihydrotestosterone formation in this tissue.

Ultrastructure of the placenta of the tammar wallaby, Macropus eugenii: comparison with the grey short‐tailed opossum, Monodelphis domestica

Publisher: Wiley

Date: 08-2002

DOI: 10.1046/J.1469-7580.2002.00084.X

Abstract: The ultrastructure of the tammar placenta was studied throughout pregnancy. The uterine epithelium grows from a columnar to an enlarged, undulating epithelium between early gestation and mid-gestation when the shell coat that surrounds the marsupial conceptus ruptures. Trophectoderm and uterine epithelium do not form syncytia, nor does invasion of the endometrium occur at any stage of pregnancy. Uterine secretion is provided to both the bilaminar and the trilaminar side of the yolk sac placenta up to birth. Fenestrations, abundant vesicles and lumenal processes of maternal capillaries, as well as deep basal folds of the uterine epithelium, suggest that there is transfer of hemotrophes adjacent to both parts of the yolk sac. In contrast, in the grey short-tailed opossum, these structures are lacking. The yolk sacs of adjacent embryos fuse to form a common yolk sac cavity, thus losing most of the bilaminar yolk sac. The bilaminar and trilaminar components of the yolk sac placenta of the tammar are less different in structure and function than those of the grey short-tailed opossum, but both types are fully functional placentas. The extended secretory phase of the tammar uterus and the maternal recognition of early pregnancy appear to be derived characters of macropodid marsupials.

Exon 3 of the growth hormone receptor (GH-R) is specific to eutherian mammals

Publisher: Elsevier BV

Date: 12-2008

DOI: 10.1016/J.MCE.2008.07.010

Abstract: Growth hormone receptor (GH-R) plays a critical role in the control of growth and metabolism in all vertebrates. GH-R consists of 9 coding exons (2-10) in all eutherian mammals, while the chicken only has 8 coding exons, and does not have an orthologous region to exon 3 in eutherians. To further understand the evolutionary origins of exon 3 of the GH-R in eutherians we cloned the full-length GH-R sequence in a marsupial, the tammar wallaby to determine whether exon 3 was present or absent in marsupial liver cDNA. There was no evidence for the presence of an exon 3 containing mRNA in sequence of tammar pouch young and adult livers. We next examined the genomes of the platypus (a monotreme mammal) and the grey short-tailed opossum (another marsupial). Like the tammar, the GH-R gene of neither species contained an exon 3. GH receptor can obviously function in the absence of this exon, raising speculation about the function of this domain, if any, in eutherians. A comparison of exon 3 protein sequences within 16 species of eutherian mammals showed that there was approximately 75% homology in the domain but only 3 of the 21 amino acids were identical (Leu12, Gln13 and Pro17). Interestingly, we detected greater evolutionary ergence in exon 3 sequences from species that have variants of GH or prolactin (PRL) in their placentas. These data show that exon 3 was inserted into the GH-R after the ergence of the marsupial and eutherian lineages at least 130 million years ago.

The marsupial model for male phenotypic development

Publisher: Elsevier BV

Date: 03-2002

DOI: 10.1016/S1043-2760(01)00525-2

Abstract: In all mammals, androgen formed in the developing testes is responsible for the aspects of male development in which the Wolffian ducts, urogenital sinus and urogenital tubercle are transformed into the epididymis/vas deferens, prostate and penis. That these events take place after birth in the marsupial makes it possible to examine male phenotypic development during pouch life. In the tammar wallaby, Macropus eugenii, the testicular androgen 5 alpha-androstane-3 alpha,17 beta-diol (5 alpha-adiol) is formed in the developing testis, is secreted into plasma and has the capacity to virilize female young pouch when administered exogenously. 5 alpha-Adiol is formed by immature testes in many species and appears to act in target tissues once it has been converted to dihydrotestosterone.

Marsupials in the Age of Genomics

Publisher: Annual Reviews

Date: 31-08-2013

DOI: 10.1146/ANNUREV-GENOM-091212-153452

Abstract: Marsupials are “alternative mammals” that differ from eutherians most spectacularly in their mode of reproduction and sexual differentiation. They represent a 160-million-year-old isolate from the more numerous eutherians, making them particularly valuable for comparative genome studies that enlarge and enhance our understanding of the function and evolution of the mammalian genome. The genomes of three sequenced marsupial species are similar in size to those of mice and humans but show informative differences in base composition and repetitive elements. Small differences in gene sets and gene families between marsupials and eutherians may relate to physiological and environmental differences. Marsupial karyotypes are highly conserved in chromosome numbers, sizes, and G-banding patterns, and an ancestor with a 2n = 14 karyotype can be deduced. Marsupial sex chromosomes, partly homologous to those of eutherians, represent the ancestral therian XY pair. Epigenetic regulation of X inactivation in marsupials differs markedly from that of eutherians and has apparently retained an ancient silencing mechanism. Genomic imprinting of a smaller set of genes occurs in the marsupial placenta and, uniquely, in the mammary gland.

Proteins in the uterine secretions of the marsupial Macropus eugenii

Publisher: Elsevier BV

Date: 05-1973

DOI: 10.1016/0012-1606(73)90218-2

Abstract: The complex life cycles of apicomplexan parasites are associated with dynamic changes of protein repertoire. In Toxoplasma gondii, global analysis of gene expression demonstrates that dynamic changes in mRNA levels unfold in a serial cascade during asexual replication and up to 50% of encoded genes are unequally expressed in development. Recent studies indicate transcription and mRNA processing have important roles in fulfilling the 'just-in-time' delivery of proteins to parasite growth and development. The prominence of post-transcriptional mechanisms in the Apicomplexa was demonstrated by mechanistic studies of the critical RNA-binding proteins and regulatory kinases. However, it is still early in our understanding of how transcription and post-transcriptional mechanisms are balanced to produce adequate numbers of specialized forms that is required to complete the parasite life cycle.

Embryos and embryonic stem cells from the white rhinoceros

Publisher: Springer Science and Business Media LLC

Date: 04-07-2018

DOI: 10.1038/S41467-018-04959-2

Abstract: The northern white rhinoceros (NWR, Ceratotherium simum cottoni ) is the most endangered mammal in the world with only two females surviving. Here we adapt existing assisted reproduction techniques (ART) to fertilize Southern White Rhinoceros (SWR) oocytes with NWR spermatozoa. We show that rhinoceros oocytes can be repeatedly recovered from live SWR females by transrectal ovum pick-up, matured, fertilized by intracytoplasmic sperm injection and developed to the blastocyst stage in vitro. Next, we generate hybrid rhinoceros embryos in vitro using gametes of NWR and SWR. We also establish embryonic stem cell lines from the SWR blastocysts. Blastocysts are cryopreserved for later embryo transfer. Our results indicate that ART could be a viable strategy to rescue genes from the iconic, almost extinct, northern white rhinoceros and may also have broader impact if applied with similar success to other endangered large mammalian species.

Comparison of mechanical and ultrasound elastic modulus of ovine tibial cortical bone

Publisher: Elsevier BV

Date: 07-2014

DOI: 10.1016/J.MEDENGPHY.2014.03.012

Abstract: Finite element models of bones can be created by deriving geometry from an X-ray CT scan. Material properties such as the elastic modulus can then be applied using either a single or set of homogeneous values, or in idual elements can have local values mapped onto them. Values for the elastic modulus can be derived from the CT density values using an elasticity versus density relationship. Many elasticity-density relationships have been reported in the literature for human bone. However, while ovine in vivo models are common in orthopaedic research, no work has been done to date on creating FE models of ovine bones. To create these models and apply relevant material properties, an ovine elasticity-density relationship needs to be determined. Using fresh frozen ovine tibias the apparent density of regions of interest was determined from a clinical CT scan. The bones were the sectioned into cuboid s les of cortical bone from the regions of interest. Ultrasound was used to determine the elastic modulus in each of three directions - longitudinally, radially and tangentially. S les then underwent traditional compression testing in each direction. The relationships between apparent density and both ultrasound, and compression modulus in each direction were determined. Ultrasound testing was found to be a highly repeatable non-destructive method of calculating the elastic modulus, particularly suited to s les of this size. The elasticity-density relationships determined in the longitudinal direction were very similar between the compression and ultrasound data over the density range examined. A clear difference was seen in the elastic modulus between the longitudinal and transverse directions of the bone s les, and a transverse elasticity-density relationship is also reported.

Evolution of vertebrate interferon inducible transmembrane proteins

Publisher: Springer Science and Business Media LLC

Date: 2012

DOI: 10.1186/1471-2164-13-155

Mammary cell-activating factor regulates the hormone-independent transcription of the early lactation protein (ELP) gene in a marsupial

Publisher: Elsevier BV

Date: 11-2016

DOI: 10.1016/J.MCE.2016.07.023

Abstract: The regulation of the tammar wallaby (Macropus eugenii) early lactation protein (ELP) gene is complex. ELP is responsive to the lactogenic hormones insulin (I), hydrocortisone (HC) and prolactin (PRL) in mammary gland explants but could not be induced with lactogenic hormones in tammar primary mammary gland cells, nor in KIM-2 conditionally immortalised murine mammary epithelial cells. Similarly, ELP promoter constructs transiently-transfected into human embryonic kidney (HEK293T) cells constitutively expressing the prolactin receptor (PRLR) and Signal Transducer and Activator of Transcription (STAT)5A were unresponsive to prolactin, unlike the rat and mouse β-casein (CSN2) promoter constructs. Identification of the minimal promoter required for the hormone-independent transcription of tammar ELP in HEK293Ts and comparative analysis of the proximal promoters of marsupial ELP and the orthologous eutherian colostrum trypsin inhibitor (CTI) gene suggests that mammary cell-activating factor (MAF), an E26 transformation-specific (ETS) factor, may bind to an AGGAAG motif and activate tammar ELP.

The genome of a Gondwanan mammal

Publisher: Wiley

Date: 2007

DOI: 10.1002/BIES.20670

Abstract: Australia is thought of as the home of marsupials, but South America has 60 or so species of these interesting mammals. The genome of one of these, the South American grey short-tailed opossum, Monodelphis domestica, has just been sequenced and published in June.1 The high quality 6x coverage is the first marsupial genome completed, pipping the 2x coverage of the Australian tammar wallaby at the post by half a year. The opossum genome has an unusual structure with fewer chromosomes than the human genome (9 pairs versus 23 pairs) but a longer total length (3.4 billion versus 3 billion bases). The opossum autosomes, like those of all marsupials, are extremely large but, in contrast, the X chromosome is only 76 Mb long. The opossum genome has turned up several surprises and provided critical new information on the evolution of mammalian genomes.

The effect of pregnant and oestrous females on male testosterone and behaviour in the tammar wallaby

Publisher: Elsevier BV

Date: 08-2010

DOI: 10.1016/J.YHBEH.2010.03.020

Abstract: Tammar wallaby females (Macropus eugenii) are seasonally breeding marsupials with a post-partum oestrus after a highly synchronised birth period when testosterone concentrations rise in males. Chemical communication appears to be important for mating, as males show checking behaviour, sniffing the urogenital opening (UGO) and the pouch of females. This study investigates whether the presence of pregnant and oestrous females directly influences testosterone in males and if oestrous odours or secretion from the pouch or UGO are attractive. Concentrations of plasma testosterone were measured in males housed with pregnant and oestrous females during two consecutive cycles in the breeding season, and an artificially induced cycle in the non-breeding season. Males were also tested for their interest in swabs taken from the urogenital opening (UGO) or pouch of oestrous females. Testosterone increased sharply in males in the presence of pregnant and oestrous females during all cycles in both seasons, but there was no change when males were exposed to non-cycling females in lactational or seasonal diapause. Males had no preference for either oestrous or non-oestrous s les taken from the pouch or from the UGO from oestrous females. This study confirms that the increase in plasma testosterone in tammar males can be induced through the presence of pregnant and oestrous females, regardless of season and that the increase began when the females were in late-pregnancy. This confirms that the male's reproductive state is dependent on a signal from females and is not blocked through seasonal effects.

Ultrastructure of the nongranulated cells and morphology of the extracellular spaces in the pars distalis of adult and pouch-young tammar wallabies (Macropus eugenii)

Publisher: Springer Science and Business Media LLC

Date: 11-1982

DOI: 10.1007/BF00210898

Preface

Publisher: S. Karger AG

Date: 2014

DOI: 10.1159/000363268

The ART of bringing extinction to a freeze - History and future of species conservation, exemplified by rhinos.

Publisher: Elsevier BV

Date: 07-2021

DOI: 10.1016/J.THERIOGENOLOGY.2021.04.006

Embryonic Diapause and Maternal Recognition of Pregnancy in Diapausing Mammals

Publisher: Springer International Publishing

Date: 2015

DOI: 10.1007/978-3-319-15856-3_12

Abstract: The dynamic nature of early embryonic growth is at odds with the phenomenon of mammalian embryonic diapause, because embryos in diapause are in a state of suspended animation of varying duration. The signals that control embryonic diapause differ between species, but in all cases, it acts to synchronise reproduction with external factors to maximise the survival of the offspring. This chapter provides an overview of current understanding of the control of embryonic diapause, with an emphasis on the three species about which most is known, namely, the mouse, the mink and the tammar wallaby.

Strategies for meiotic sex chromosome dynamics and telomeric elongation in Marsupials

Publisher: Public Library of Science (PLoS)

Date: 07-02-2022

DOI: 10.1371/JOURNAL.PGEN.1010040

Abstract: During meiotic prophase I, homologous chromosomes pair, synapse and recombine in a tightly regulated process that ensures the generation of genetically variable haploid gametes. Although the mechanisms underlying meiotic cell ision have been well studied in model species, our understanding of the dynamics of meiotic prophase I in non-traditional model mammals remains in its infancy. Here, we reveal key meiotic features in previously uncharacterised marsupial species (the tammar wallaby and the fat-tailed dunnart), plus the fat-tailed mouse opossum, with a focus on sex chromosome pairing strategies, recombination and meiotic telomere homeostasis. We uncovered differences between phylogroups with important functional and evolutionary implications. First, sex chromosomes, which lack a pseudo-autosomal region in marsupials, had species specific pairing and silencing strategies, with implications for sex chromosome evolution. Second, we detected two waves of γH2AX accumulation during prophase I. The first wave was accompanied by low γH2AX levels on autosomes, which correlated with the low recombination rates that distinguish marsupials from eutherian mammals. In the second wave, γH2AX was restricted to sex chromosomes in all three species, which correlated with transcription from the X in tammar wallaby. This suggests non-canonical functions of γH2AX on meiotic sex chromosomes. Finally, we uncover evidence for telomere elongation in primary spermatocytes of the fat-tailed dunnart, a unique strategy within mammals. Our results provide new insights into meiotic progression and telomere homeostasis in marsupials, highlighting the importance of capturing the ersity of meiotic strategies within mammals.

Clinical use of diodes and micro-chambers to obtain accurate small field output factor measurements

Publisher: Springer Science and Business Media LLC

Date: 06-03-2015

DOI: 10.1007/S13246-015-0334-9

Abstract: There have been substantial advances in small field dosimetry techniques and technologies, over the last decade, which have dramatically improved the achievable accuracy of small field dose measurements. This educational note aims to help radiation oncology medical physicists to apply some of these advances in clinical practice. The evaluation of a set of small field output factors (total scatter factors) is used to exemplify a detailed measurement and simulation procedure and as a basis for discussing the possible effects of simplifying that procedure. Field output factors were measured with an unshielded diode and a micro-ionisation chamber, at the centre of a set of square fields defined by a micro-multileaf collimator. Nominal field sizes investigated ranged from 6 × 6 to 98 × 98 mm(2). Diode measurements in fields smaller than 30 mm across were corrected using response factors calculated using Monte Carlo simulations of the diode geometry and daisy-chained to match micro-chamber measurements at intermediate field sizes. Diode measurements in fields smaller than 15 mm across were repeated twelve times over three separate measurement sessions, to evaluate the reproducibility of the radiation field size and its correspondence with the nominal field size. The five readings that contributed to each measurement on each day varied by up to 0.26 %, for the "very small" fields smaller than 15 mm, and 0.18 % for the fields larger than 15 mm. The diode response factors calculated for the unshielded diode agreed with previously published results, within uncertainties. The measured dimensions of the very small fields differed by up to 0.3 mm, across the different measurement sessions, contributing an uncertainty of up to 1.2 % to the very small field output factors. The overall uncertainties in the field output factors were 1.8 % for the very small fields and 1.1 % for the fields larger than 15 mm across. Recommended steps for acquiring small field output factor measurements for use in radiotherapy treatment planning system beam configuration data are provided.

Foetal age determination and development in elephants

Publisher: The Royal Society

Date: 31-10-2006

DOI: 10.1098/RSPB.2006.3738

Abstract: Elephants have the longest pregnancy of all mammals, with an average gestation of around 660 days, so their embryonic and foetal development have always been of special interest. Hitherto, it has only been possible to estimate foetal ages from theoretical calculations based on foetal mass. The recent development of sophisticated ultrasound procedures for elephants has now made it possible to monitor the growth and development of foetuses of known gestational age conceived in captivity from natural matings or artificial insemination. We have studied the early stages of pregnancy in 10 captive Asian and 9 African elephants by transrectal ultrasound. Measurements of foetal crown–rump lengths have provided the first accurate growth curves, which differ significantly from the previous theoretical estimates based on the cube root of foetal mass. We have used these to age 22 African elephant foetuses collected during culling operations. Pregnancy can be first recognized ultrasonographically by day 50, the presumptive yolk sac by about day 75 and the zonary placenta by about day 85. The trunk is first recognizable by days 85–90 and is distinct by day 104, while the first heartbeats are evident from around day 80. By combining ultrasonography and morphology, we have been able to produce the first reliable criteria for estimating gestational age and ontological development of Asian and African elephant foetuses during the first third of gestation.

Historical range and movements of the Elephants in Babile Elephant Sanctuary, Ethiopia

Publisher: Wiley

Date: 02-05-2012

DOI: 10.1111/J.1365-2028.2012.01336.X

Adapting a generic BEAMnrc model of the BrainLAB m3 micro-multileaf collimator to simulate a local collimation device

Publisher: IOP Publishing

Date: 11-08-2010

DOI: 10.1088/0031-9155/55/17/N01

A 3D-printed passive ultrasound phase-interference compensator for reduced wave degradation in cancellous bone – an experimental study in replica models

Publisher: SAGE Publications

Date: 2018

DOI: 10.1177/2041731418766418

Abstract: The current ‘active’ solution to overcome the impediment of ultrasound wave degradation associated with transit-time variation in complex tissue structures, such as the skull, is to vary the transmission delay of ultrasound pulses from in idual transducer elements. This article considers a novel ‘passive’ solution in which constant transit time is achieved by propagating through an additional material layer positioned between the ultrasound transducer and the test s le. To test the concept, replica models based on four cancellous bone natural tissue s les and their corresponding passive ultrasound phase-interference compensator were 3D-printed. Normalised broadband ultrasound attenuation was used as a quantitative measure of wave degradation, performed in transmission mode at a frequency of 1 MHz and yielding a reduction ranging from 57% to 74% when the ultrasound phase-interference compensator was incorporated. It is suggested that the passive compensator offers a broad utility and, hence, it may be applied to any ultrasound transducer, of any complexity (single element or array), frequency and dimension.

Parturition and perfect prematurity: birth in marsupials

Publisher: CSIRO Publishing

Date: 2006

DOI: 10.1071/ZO05070

Abstract: Marsupials are distinguished from eutherian mammals in their mode of reproduction. They give birth to a highly altricial young, which completes its development whilst attached to a teat, usually within a pouch. The marsupial neonate has relatively well-developed digestive, respiratory and circulatory systems but retains its fetal excretory system with a fully functional mesonephric kidney and undifferentiated gonads and genitalia. We have investigated birth in the tammar wallaby (Macropus eugenii) and shown that the tiny (400 mg) fetus determines the time of its own delivery. Although plasma progesterone falls, and oestradiol associated with the postpartum oestrus typically rises, around the time of parturition, neither hormone is essential for the timing of birth. However relaxin may loosen the connective tissue of the cervix and vaginae for birth. Labour starts suddenly and is completed within minutes. Both prostaglandins and mesotocin are essential for the contractions that deliver the young. Prostaglandins from the reproductive tract act via the brain to control parturient behaviour. In the last 2 days of gestation fetal adrenal glucocorticoid production increases, promoting lung maturation and surfactant production and ultimately triggering labour. The accessibility of the altricial neonatal marsupial provides a unique opportunity for experimental manipulation of organ development and maturation.

Postnatal epigenetic reprogramming in the germline of a marsupial, the tammar wallaby

Publisher: Springer Science and Business Media LLC

Date: 03-06-2013

DOI: 10.1186/1756-8935-6-14

Pre- and postnatal development of lactate and malate dehydrogenases in the marsupial didelphis marsupialis virginiana

Publisher: Elsevier BV

Date: 11-1975

DOI: 10.1016/0305-0491(75)90142-X

Differential roles of TGIF family genes in mammalian reproduction

Publisher: Springer Science and Business Media LLC

Date: 29-09-2011

DOI: 10.1186/1471-213X-11-58

Abstract: TG-interacting factors (TGIFs) belong to a family of TALE-homeodomain proteins including TGIF1, TGIF2 and TGIFLX/Y in human. Both TGIF1 and TGIF2 act as transcription factors repressing TGF-β signalling. Human TGIFLX and its orthologue, Tex1 in the mouse, are X-linked genes that are only expressed in the adult testis. TGIF2 arose from TGIF1 by duplication, whereas TGIFLX arose by retrotransposition to the X-chromosome. These genes have not been characterised in any non-eutherian mammals. We therefore studied the TGIF family in the tammar wallaby (a marsupial mammal) to investigate their roles in reproduction and how and when these genes may have evolved their functions and chromosomal locations. Both TGIF1 and TGIF2 were present in the tammar genome on autosomes but TGIFLX was absent. Tammar TGIF1 shared a similar expression pattern during embryogenesis, sexual differentiation and in adult tissues to that of TGIF1 in eutherian mammals, suggesting it has been functionally conserved. Tammar TGIF2 was ubiquitously expressed throughout early development as in the human and mouse, but in the adult, it was expressed only in the gonads and spleen, more like the expression pattern of human TGIFLX and mouse Tex1 . Tammar TGIF2 mRNA was specifically detected in round and elongated spermatids. There was no mRNA detected in mature spermatozoa. TGIF2 protein was specifically located in the cytoplasm of spermatids, and in the residual body and the mid-piece of the mature sperm tail. These data suggest that tammar TGIF2 may participate in spermiogenesis, like TGIFLX does in eutherians. TGIF2 was detected for the first time in the ovary with mRNA produced in the granulosa and theca cells, suggesting it may also play a role in folliculogenesis. The restricted and very similar expression of tammar TGIF2 to X-linked paralogues in eutherians suggests that the evolution of TGIF1 , TGIF2 and TGIFLX in eutherians was accompanied by a change from ubiquitous to tissue-specific expression. The distribution and localization of TGIF2 in tammar adult gonads suggest that there has been an ultra-conserved function for the TGIF family in fertility and that TGIF2 already functioned in spermatogenesis and potentially folliculogenesis long before its retrotransposition to the X-chromosome of eutherian mammals. These results also provide further evidence that the eutherian X-chromosome has actively recruited sex and reproductive-related genes during mammalian evolution.

The effect of very small air gaps on small field dosimetry

Publisher: IOP Publishing

Date: 09-10-2012

DOI: 10.1088/0031-9155/57/21/6947

Abstract: The purpose of this study was to investigate the effect of very small air gaps (less than 1 mm) on the dosimetry of small photon fields used for stereotactic treatments. Measurements were performed with optically stimulated luminescent dosimeters (OSLDs) for 6 MV photons on a Varian 21iX linear accelerator with a Brainlab µMLC attachment for square field sizes down to 6 mm × 6 mm. Monte Carlo simulations were performed using EGSnrc C++ user code cavity. It was found that the Monte Carlo model used in this study accurately simulated the OSLD measurements on the linear accelerator. For the 6 mm field size, the 0.5 mm air gap upstream to the active area of the OSLD caused a 5.3% dose reduction relative to a Monte Carlo simulation with no air gap. A hypothetical 0.2 mm air gap caused a dose reduction >2%, emphasizing the fact that even the tiniest air gaps can cause a large reduction in measured dose. The negligible effect on an 18 mm field size illustrated that the electronic disequilibrium caused by such small air gaps only affects the dosimetry of the very small fields. When performing small field dosimetry, care must be taken to avoid any air gaps, as can be often present when inserting detectors into solid phantoms. It is recommended that very small field dosimetry is performed in liquid water. When using small photon fields, sub-millimetre air gaps can also affect patient dosimetry if they cannot be spatially resolved on a CT scan. However the effect on the patient is debatable as the dose reduction caused by a 1 mm air gap, starting out at 19% in the first 0.1 mm behind the air gap, decreases to <5% after just 2 mm, and electronic equilibrium is fully re-established after just 5 mm.

Conservation of the H19 noncoding RNA and H19-IGF2 imprinting mechanism in therians

Publisher: Springer Science and Business Media LLC

Date: 29-06-2008

DOI: 10.1038/NG.168

Abstract: Comparisons between eutherians and marsupials suggest limited conservation of the molecular mechanisms that control genomic imprinting in mammals. We have studied the evolution of the imprinted IGF2-H19 locus in therians. Although marsupial orthologs of protein-coding exons were easily identified, the use of evolutionarily conserved regions and low-stringency Bl2seq comparisons was required to delineate a candidate H19 noncoding RNA sequence. The therian H19 orthologs show miR-675 and exon structure conservation, suggesting functional selection on both features. Transcription start site sequences and poly(A) signals are also conserved. As in eutherians, marsupial H19 is maternally expressed and paternal methylation upstream of the gene originates in the male germline, encompasses a CTCF insulator, and spreads somatically into the H19 gene. The conservation in all therians of the mechanism controlling imprinting of the IGF2-H19 locus suggests a sequential model of imprinting evolution.

The Tammar Wallaby, Macropus eugenii: A model kangaroo for the study of developmental and reproductive biology

Publisher: Cold Spring Harbor Laboratory

Date: 12-2009

DOI: 10.1101/PDB.EMO137

Abstract: The tammar wallaby (Macropus eugenii) is the best-studied marsupial in terms of its reproduction and development. It fares well in captivity, is large enough to take serial blood s les from, and its young are accessible in the pouch for experimental manipulation. These features have made it an excellent model for both physiological and molecular research. It is a seasonal, monovular breeder, but also has a lactational control of its reproduction, as well as embryonic diapause. As in all marsupials, the composition of the milk changes throughout the lengthy lactation, and the dynamic changes that occur in the genes and secreted proteins of the mammary gland have now been characterized. Studies of the tammar have contributed to our understanding of the control of reproduction in all mammals, and more recently, have helped clarify the endocrine and molecular aspects of sexual differentiation. The completion of the tammar wallaby genome will facilitate further study of this marsupial.

Development of the Penile Urethra in the Tammar Wallaby

Publisher: S. Karger AG

Date: 2011

DOI: 10.1159/000334053

Abstract: Hypospadias is increasingly common, and requires surgery to repair, but its aetiology is poorly understood. The marsupial tammar wallaby provides a unique opportunity to study hypospadias because penile differentiation occurs postnatally. Androgens are responsible for penile development in the tammar, but the majority of differentiation, in particular formation and closure of the urethral groove forming the penile urethra in males, occurs when there is no measurable sex difference in the concentrations of testosterone, dihydrotestosterone or androstanediol in either the gonads or the circulation. Phalluses were examined morphologically from the sexually indifferent period (when androgens are high) to well after the time that the phallus becomes sexually dimorphic. We show that penile development and critical changes in the positioning of the urethra occur in the male phallus begin during an early window of time when androgens are high. Remodelling of the urethra in the male occurs between days 20–60. The critical period of time for the establishment urethral closure occurs during the earliest phases of penile development. This study suggests that there is an early window of time before day 60 when androgen imprinting must occur for normal penile development and closure of the urethral groove.

On the origin of POU5F1.

Publisher: Springer Science and Business Media LLC

Date: 09-05-2013

DOI: 10.1186/1741-7007-11-56

Early onset of ghrelin production in a marsupial

Publisher: Elsevier BV

Date: 02-2009

DOI: 10.1016/J.MCE.2008.10.033

Abstract: Ghrelin regulates appetite in mammals and can stimulate growth hormone (GH) release from the pituitary. In rats and humans, ghrelin cells appear in the stomach during late fetal life. Nevertheless, the role of ghrelin in early mammalian development is not well understood. Marsupials deliver highly altricial young that weigh less than 1g so they must feed and digest milk at a comparatively immature stage of development. Since they complete their growth and differentiation while in the pouch, they are accessible models in which to determine the time course of ghrelin production during development. We examined the distribution of gastric ghrelin cells, plasma ghrelin concentrations and pituitary expression of the ghrelin receptor (ghsr-1alpha) and GH in the tammar wallaby, Macropus eugenii. There were ghrelin immunopositive cells in the developing mesenchyme of the stomach from day 10 post partum (pp) to day 150pp. Subsequently ghrelin protein in the fore-stomach declined and was absent by day 250pp but remained in the gastric cells of the hind-stomach. Ghrelin was detected in the developing pancreas from day 10pp but was absent by day 150pp and in the adult. Pituitary ghsr-1alpha expression and plasma concentrations of ghrelin increased significantly up to day 70-120pp while GH expression was also elevated, declining with GH to reach adult levels by day 180pp. These results demonstrate an early onset of gastric ghrelin expression in the tammar in concert with a functional stomach at a relatively earlier stage than that of developmentally more mature eutherian young.

The mammalian yolk sac placenta

Publisher: Wiley

Date: 04-11-2008

DOI: 10.1002/JEZ.B.21239

Abstract: There are three fetal membranes in mammals, namely the yolk sac, allantois and amnion, but only the first two form a placenta. In Monotremata (monotremes), Marsupialia (marsupials) and Placentalia (eutherians), the yolk sac transfers nutrients originating from uterine glandular secretion or the maternal blood. Ontogenetically, the yolk sac of most eutherians loses contact with the peripheral chorion and forms a free splanchnopleuric yolk sac that transfers substances from the exocoelomic cavity, not directly from the endometrium as in marsupials and rodents. This free yolk sac has been preserved in humans and substances originating from glandular secretions are transferred from the exocoelomic cavity to the embryo via this route. The therian yolk sac expresses numerous growth and transcription factors, associated binding proteins and receptors that control its differentiation and function, including hematopoiesis and angiogenesis. Errors in yolk sac development and function could contribute to embryonic malformation, miscarriage and growth diseases. Factors regulating transfer and metabolism, notably insulin and IGF2, are imprinted in the human yolk sac, as in all therians so far studied. This suggests persistence of a strong selective pressure for parentally controlled allocation of resources to the growing embryo via this fetal membrane. The metabolic and biosynthetic functions of the yolk sac of the ancestral therian stem species, as well as hematopoiesis in the eutherian ancestor, appear to have been retained by the human yolk sac. Thus, the yolk sac of humans, like that of all viviparous mammals, is a true placenta crucial for early embryonic development and survival.

Conserved H3K27me3-associated chromatin remodelling allows STRA8 but not MEIOSIN expression in mammalian germ cells

Publisher: Bioscientifica

Date: 03-03-2023

DOI: 10.1530/REP-22-0286

Abstract: Apart from mice, meiosis initiation factors and their transcriptional regulation mechanisms are largely unknown in mammals. This study suggests that STRA8 and MEIOSIN are both meiosis initiation factors in mammals, but their transcription is epigenetically regulated differently from each other. In the mouse, the timing of meiosis onset differs between sexes due to the sex-specific regulation of the meiosis initiation factors, STRA8 and MEIOSIN. Before the initiation of meiotic prophase I, the Stra8 promoter loses suppressive histone-3-lysine-27 trimethylation (H3K27me3) in both sexes, suggesting that H3K27me3-associated chromatin remodelling may be responsible for activating STRA8 and its co-factor MEIOSIN . Here we examined MEIOSIN and STRA8 expression in a eutherian (the mouse), two marsupials (the grey short-tailed opossum and the tammar wallaby) and two monotremes (the platypus and the short-beaked echidna) to ask whether this pathway is conserved between all mammals. The conserved expression of both genes in all three mammalian groups and of MEIOSIN and STRA8 protein in therian mammals suggests that they are the meiosis initiation factors in all mammals. Analyses of published DNase-seq and chromatin-immunoprecipitation sequencing (ChIP-seq) data sets confirmed that H3K27me3-associated chromatin remodelling occurred at the STRA8, but not the MEIOSIN, promoter in therian mammals. Furthermore, culturing tammar ovaries with an inhibitor of H3K27me3 demethylation before meiotic prophase I affected STRA8 but not MEIOSIN transcriptional levels. Our data suggest that H3K27me3-associated chromatin remodelling is an ancestral mechanism that allows STRA8 expression in mammalian pre-meiotic germ cells.

Administration of 5α-Androstane-3α,17β-Diol to Female Tammar Wallaby Pouch Young Causes Development of a Mature Prostate and Male Urethra

Publisher: The Endocrine Society

Date: 07-2002

DOI: 10.1210/ENDO.143.7.8917

Abstract: Secretion of 5α-androstane-3α,17β-diol (5α-adiol) by the testes of the tammar wallaby is responsible for initiation of prostatic development after d 20 in male pouch young. To ascertain the role of this hormone in the subsequent growth and differentiation of the prostate and in the development of the male phallus, 5α-adiol was administered to tammar female pouch young in two regimens. Administration of the hormone by mouth (8 μg/g body weight·wk) between d 70 and 150 of pouch life caused prostate development equivalent to that in d 150 males and promoted growth and differentiation of the penis, but not masculinization of the urethra. Treatment with a small dose of 5α-adiol enanthate (1 μg/g body weight·wk) from d 20–150 produced similar results. However, administration of larger doses of 5α-adiol enanthate (10 or 100 μg/g body weight·wk) from d 20–150 caused supraphysiological growth of the prostate, development of a male-type urethra, and penile growth. These results indicate that prostatic development and penile growth can be initiated over a wide time period, but that formation of a male urethra requires androgen action before d 70, when male penile differentiation begins. This further strengthens the hypothesis that 5α-adiol is the circulating androgen responsible in this species for virilization during development.

Whole-mount immunohistochemical staining of Tammar Wallaby (Macropus eugenii) cleavage stages and blastocysts

Publisher: Cold Spring Harbor Laboratory

Date: 12-2009

DOI: 10.1101/PDB.PROT5339

Abstract: This protocol describes a method for whole-mount immunofluorescence staining of early stages of tammar wallaby ( Macropus eugenii ) development, including cleavage and unilaminar blastocysts. Conceptuses of these stages are surrounded by a shell coat, which must be removed before staining to ensure proper penetration of all solutions.

Ultrasound treatment of neurological diseases — current and emerging applications

Publisher: Springer Science and Business Media LLC

Date: 19-02-2016

DOI: 10.1038/NRNEUROL.2016.13

Abstract: Like cardiovascular disease and cancer, neurological disorders present an increasing challenge for an ageing population. Whereas nonpharmacological procedures are routine for eliminating cancer tissue or opening a blocked artery, the focus in neurological disease remains on pharmacological interventions. Setbacks in clinical trials and the obstacle of access to the brain for drug delivery and surgery have highlighted the potential for therapeutic use of ultrasound in neurological diseases, and the technology has proved useful for inducing focused lesions, clearing protein aggregates, facilitating drug uptake, and modulating neuronal function. In this Review, we discuss milestones in the development of therapeutic ultrasound, from the first steps in the 1950s to recent improvements in technology. We provide an overview of the principles of diagnostic and therapeutic ultrasound, for surgery and transient opening of the blood-brain barrier, and its application in clinical trials of stroke, Parkinson disease and chronic pain. We discuss the promising outcomes of safety and feasibility studies in preclinical models, including rodents, pigs and macaques, and efficacy studies in models of Alzheimer disease. We also consider the challenges faced on the road to clinical translation.

Culturing Tammar Wallaby (Macropus eugenii) peri-gastrulation stage embryos

Publisher: Cold Spring Harbor Laboratory

Date: 12-2009

DOI: 10.1101/PDB.PROT5337

Abstract: Tammar wallaby (Macropus eugenii) peri-gastrulation stage embryos can be cultured in complete medium in 95% oxygen for up to 3 d. There is little apparent difference in terms of development between tammar peri-gastrulation stage embryos cultured in DMEM versus Medium 199 with Earle’s salts, or between the supplementation of complete medium with either 10% fetal calf serum (FCS) or 10% wallaby serum (WS). The peri-gastrulation marsupial conceptus is hollow, which means that some techniques, such as grafting, cannot be performed on embryos to be cultured whole because, once punctured, the embryo collapses and does not reinflate. This protocol describes both whole embryo culture and an alternative method of culture. In the latter method, the embryonic disc and some adjoining vascular yolk sac are isolated, laid flat on a membrane, and cultured as a flat mount. Embryos cultured in this way develop to a similar stage as those cultured whole.

Technical Note: Modeling a complex micro-multileaf collimator using the standard BEAMnrc distribution

Publisher: Wiley

Date: 26-03-2010

DOI: 10.1118/1.3355873

Abstract: The component modules in the standard BEAMnrc istribution may appear to be insufficient to model micro-multileaf collimators that have trifaceted leaf ends and complex leaf profiles. This note indicates, however, that accurate Monte Carlo simulations of radiotherapy beams defined by a complex collimation device can be completed using BEAMnrc's standard VARMLC component module. That this simple collimator model can produce spatially and dosimetrically accurate microcollimated fields is illustrated using comparisons with ion chamber and film measurements of the dose deposited by square and irregular fields incident on planar, homogeneous water phantoms. Monte Carlo dose calculations for on-axis and off-axis fields are shown to produce good agreement with experimental values, even on close examination of the penumbrae. The use of a VARMLC model of the micro-multileaf collimator, along with a commissioned model of the associated linear accelerator, is therefore recommended as an alternative to the development or use of in-house or third-party component modules for simulating stereotactic radiotherapy and radiosurgery treatments. Simulation parameters for the VARMLC model are provided which should allow other researchers to adapt and use this model to study clinical stereotactic radiotherapy treatments.

Effect of steroids on thyroid activity and adrenal morphology in tammar wallabies after removal of the corpus luteum

Publisher: Elsevier BV

Date: 1982

DOI: 10.1016/0300-9629(82)90190-6

Abstract: 1. Plasma total thyroxine (TT4) levels and plasma free thyroxine (FT4) index were significantly lower in adult tammar wallabies (Macropus eugenii) from which the corpus luteum had been removed than in sham-operated controls. 2. Progesterone injections given for 14 days after corpus lutectomy significantly elevated the plasma free tri-iodothyronine (FT3) index, but had no effect on other thyroid parameters measured. 3. Estrogen and androstenedione given for 14 days after corpus lutectomy had no significant effect on any of the thyroid parameters measured, although in both groups injected with these steroids, the histological appearance of the thyroid was suggestive of an increased activity. 4. The adrenal weight, adrenal somatic index, adrenal cortex area, zona fasciculata width, and zona reticularis width were significantly larger in estrogen-injected corpus lutectomized wallabies than in oil-injected corpus lutectomized controls.

Foreword to 'From Elephants to AIDS. Essays in Biology in Honour of Roger V. Short'

Publisher: CSIRO Publishing

Date: 2001

DOI: 10.1071/RDV13N8_FO

Immunohistochemical staining of sectioned Tammar Wallaby (Macropus eugenii) tissue

Publisher: Cold Spring Harbor Laboratory

Date: 12-2009

DOI: 10.1101/PDB.PROT5338

Abstract: Although standard immunohistochemical protocols are used for staining tammar wallaby (Macropus eugenii) tissues, sometimes the tammar protein sequence differs slightly from that of the species against which the antibody was raised. If possible, obtain sequence for the marsupial protein to see which regions of the protein are the most highly conserved between marsupials and eutherians. When purchasing an antibody, if possible, choose one that has shown reactivity across a broad range of species, and preferably choose a polyclonal rather than a monoclonal. Because a tammar epitope may differ slightly from the one against which an antibody was raised, it may be affected differently by fixation, especially if fixatives (such as paraformaldehyde [PFA] or formalin) that cross-link proteins are used. When testing a new antibody on tammar tissues, we therefore routinely test numerous pretreatments to see which one gives optimal staining. In some cases, the optimal pretreatment differs from that suggested by the manufacturer of the antibody. This protocol describes how to use the avidin-biotin complex detection method on paraffin-embedded specimens.

Placental expression of pituitary hormones is an ancestral feature of therian mammals

Publisher: Springer Science and Business Media LLC

Date: 2011

DOI: 10.1186/2041-9139-2-16

Effects of nutritional manipulation on body composition in the developing marsupial, Macropus eugenii

Publisher: Elsevier BV

Date: 06-2016

DOI: 10.1016/J.MCE.2016.03.030

Abstract: When 60-day-old tammar wallaby pouch young (Macropus eugenii) are fostered to mothers at 120 days of lactation, their growth, developmental rate and maturation of their GH/IGF axes are markedly accelerated. To determine the effect of fostering on energy intake, body composition and fat accretion, we first measured total body fat and lean mass in these young. Next, we mimicked the triglyceride oleic and palmitic acid composition of 120-day milk by supplementing 60 day young with these fatty acids and comparing their growth with that of growth accelerated young. There was no difference in the weight or growth axis maturation of supplemented young but there was significantly more body fat in these and in the growth-accelerated fostered young than in controls. We conclude that the accelerated growth and GH/IGF axis maturation observed previously in fostered young is most likely due to increased milk consumption and earlier access to specific nutrients.

A 3D printed phantom to assess MRI geometric distortion

Publisher: IOP Publishing

Date: 15-03-2021

DOI: 10.1088/2057-1976/ABEB7E

Abstract: Geometric distortions in magnetic resonance can introduce significant uncertainties into applications such as radiotherapy treatment planning and need to be assessed as part of a comprehensive quality assurance program. We report the design, fabrication, and imaging of a custom 3D printed unibody MR distortion phantom along with quantitative image analysis. Methods : The internal cavity of the phantom is an orthogonal three-dimensional planar lattice, composed of 3 mm diameter rods spaced equidistantly at a 20 mm centre-centre offset repeating along the X, Y, and Z axes. The phantom featured an overall length of 308.5 mm, a width of 246 mm, and a height of 264 mm with lines on the external surface for phantom positioning matched to external lasers. The MR phantom was 3D printed in Nylon-12 using an advancement on traditional selective laser sintering (SLS) (HP Jet Fusion 3D—4200 machine). The phantom was scanned on a Toshiba Aquilion CT scanner to check the integrity of the 3D print and correct for any resultant issues. The phantom was then filled with NiSO 4 solution and scanned on a 3T PET-MR Siemens scanner for selected T1 and T2 sequences, from which distortion vectors were generated and analysed using in-house software written in Python. Results : All deviations of the node positions from the print design were less than 1 mm, with an average displacement of 0.228 mm. The majority of the deviations were smaller than the 0.692 mm pixel size for this dataset. Conclusion : A customised 3D printed MRI-phantom was successfully printed and tested for assessing geometric distortion on MRI scanners. 3D printed phantoms can be considered for clinics wishing to assess geometric distortions under specific conditions, but require resources for design, fabrication, commissioning, and verification.

Kallmann syndrome 1 gene is expressed in the marsupial gonad

Publisher: Oxford University Press (OUP)

Date: 03-2011

DOI: 10.1095/BIOLREPROD.110.087437

Abstract: Kallmann syndrome is characterized by hypogonadotrophic hypogonadism and anosmia. The syndrome can be caused by mutations in several genes, but the X-linked form is caused by mutation in the Kallmann syndrome 1 (KAL1). KAL1 plays a critical role in gonadotropin-releasing hormone (GnRH) neuronal migration that is essential for the normal development of the hypothalamic-pituitary-gonadal axis. Interestingly, KAL1 appears to be missing from the rodent X, and no orthologue has been detected as yet. We investigated KAL1 during development and in adults of an Australian marsupial, the tammar wallaby, Macropus eugenii. Marsupial KAL1 maps to an autosome within a group of genes that was added as a block to the X chromosome in eutherian evolution. KAL1 expression was widespread in embryonic and adult tissues. In the adult testis, tammar KAL1 mRNA and protein were detected in the germ cells at specific stages of differentiation. In the adult testis, the protein encoded by KAL1, anosmin-1, was restricted to the round spermatids and elongated spermatids. In the adult ovary, anosmin-1 was not only detected in the oocytes but was also localized in the granulosa cells throughout folliculogenesis. This is the first examination of KAL1 mRNA and protein localization in adult mammalian gonads. The protein localization suggests that KAL1 participates in gametogenesis not only through the development of the hypothalamic-pituitary-gonadal axis by activation of GnRH neuronal migration, but also directly within the gonads themselves. Because KAL1 is autosomal in marsupials but is X-linked in eutherians, its conserved involvement in gametogenesis supports the hypothesis that reproduction-related genes were actively recruited to the eutherian X chromosome.

Maternal recognition of pregnancy in marsupials

Publisher: Bioscientifica

Date: 2000

DOI: 10.1530/ROR.0.0050006

Abstract: Pregnancy in kangaroos and wallabies (macropodid marsupials) induces multiple unilateral responses in the reproductive system that override those related to proximity to the single corpus luteum on one ovary or to the follicle on the contralateral ovary. This situation is in contrast to most other non-macropodid marsupials, in which the responses are dependent on the corpus luteum. There is now good evidence that these unilateral responses in macropodids are controlled by the feto-placental unit acting locally to stimulate the endometrium and myometrium. Pregnancy also influences the duration of the oestrous cycle and maternal behaviour. The stimuli responsible for these effects probably include paracrine, endocrine and mechanical stimuli resulting from uterine stretch. Taken together, these unilateral responses demonstrate that there is a refined maternal recognition of pregnancy in at least the macropodid marsupials.

Working with Tammar Wallabies (Macropus eugenii)

Publisher: Cold Spring Harbor Laboratory

Date: 12-2009

DOI: 10.1101/PDB.PROT5332

Abstract: It requires practice to become adept at catching and handling tammar wallabies ( Macropus eugenii) . Although generally not aggressive, tammars do scratch and can also bite. Once caught, tammars will stay quiet in their sacks for several hours. Take care that sacked animals do not overheat by ensuring that they are not left in the sun or piled on top of each other. To avoid the risk of heat stress, do not catch animals when air temperatures are above 25°C. Once handling techniques for adult animals are mastered, procedures such as vaccinations and checking for pouch young (PY) are easily performed, as described in this protocol. Methods for sexing, aging, and handling PY, as well as euthanasia of PY, are also detailed in this protocol. Once removed from the pouch, PY must be kept warm, because they lack the ability to thermoregulate until they are ~6 mo old.

Paf receptor expression in the marsupial embryo and endometrium during embryonic diapause

Publisher: Bioscientifica

Date: 2014

DOI: 10.1530/REP-13-0140

Abstract: The control of reactivation from embryonic diapause in the tammar wallaby ( Macropus eugenii ) involves sequential activation of the corpus luteum, secretion of progesterone that stimulates endometrial secretion and subsequent changes in the uterine environment that activate the embryo. However, the precise signals between the endometrium and the blastocyst are currently unknown. In eutherians, both the phospholipid Paf and its receptor, platelet-activating factor receptor (PTAFR), are present in the embryo and the endometrium. In the tammar, endometrial Paf release in vitro increases around the time of the early progesterone pulse that occurs around the time of reactivation, but whether Paf can reactivate the blastocyst is unknown. We cloned and characterised the expression of PTAFR in the tammar embryo and endometrium at entry into embryonic diapause, during its maintenance and after reactivation. Tammar PTAFR sequence and protein were highly conserved with mammalian orthologues. In the endometrium, PTAFR was expressed at a constant level in the glandular epithelium across all stages and in the luminal epithelium during both diapause and reactivation. Thus, the presence of the receptor appears not to be a limiting factor for Paf actions in the endometrium. However, the low levels of PTAFR in the embryo during diapause, together with its up-regulation and subsequent internalisation at reactivation, supports earlier results suggesting that endometrial Paf could be involved in reactivation of the tammar blastocyst from embryonic diapause.

The dependence of broadband ultrasound attenuation on phase interference in thin plates of variable thickness and curvature: a comparison of experimental measurement and computer simulation

Publisher: SAGE Publications

Date: 28-03-2018

DOI: 10.1177/0954411918762145

Abstract: The measurement of broadband ultrasound attenuation describes the linear increase in ultrasound attenuation with frequency (dB/MHz) this is generally performed at the calcaneus, consisting of a high proportion of metabolically active cancellous bone. Although broadband ultrasound attenuation is not routinely implemented within clinical management since it cannot provide a reliable estimation of bone mineral density and hence clinical definition of osteopenia and osteoporosis, it offers a reliable means to predict osteoporotic fracture risk. One of the potential factors that can influence the accuracy of broadband ultrasound attenuation measurement is the effect of cortical end plates. This study aimed to explore this, performing a comparison of experimental study and computer simulation prediction. A total of three categories of thin discs were three-dimensional (3D) printed to replicate cortical shells of (1) variable constant thickness (planar), (2) variable constant thickness (curved), and (3) variable thickness. A through-transmission technique was used, where two single-element, unfocused, 1 MHz broadband transducers, as utilised clinically, were positioned coaxially in a cylindrical holder and immersed in water. Both quantitative and qualitative analyses demonstrated that broadband ultrasound attenuation measurements of the ‘planar’ and ‘curved’ discs were not statistically different (p-values 0.01). A cyclic relationship between broadband ultrasound attenuation and disc thickness was observed this was replicated within a computer simulation of phase interference created by a double-reflection echo within each disc (R 2 = 97.0%). Variable-thickness discs provided broadband ultrasound attenuation measurements ranging between 31.6 ± 0.1 and 40.60 ± 0.1 dB/MHz. Again applying the double-reflection echo simulation, a high level of agreement between experimental and simulation was recorded (R 2 = 93.4%). This study indicates that the cortical end plate can significantly affect the broadband ultrasound attenuation measurement of cancellous bone as a result of phase interference and, therefore, warrants further investigation to minimise its effect on clinical assessment.

A review of the magnitude and response times for sediment yield reductions following the rehabilitation of gullied landscapes

Publisher: Wiley

Date: 15-08-2020

DOI: 10.1002/ESP.4963

Abstract: Gully erosion is a major driver of elevated sediment yields across many areas of the globe, and considerable rehabilitation has occurred to reduce the amount of sediment eroded from gullies. However, compared to other forms of erosion, there has been little systematic review of the effectiveness of gully rehabilitation on reducing sediment yields. This study reviewed the global literature to provide an understanding of the potential sediment yield reductions that can occur following the rehabilitation of gullied landscapes. We focused on studies reporting a measured response on how gully and catchment sediment yield has changed since treatment. A total of 37 studies were found that met this criterion. The studies were partitioned into three broad categories, including those focused on: (i) treating the catchment above the gully (ii) installing treatments in the actual gully channel and (iii) a combination of approaches which include treating both the catchment and the gully channel. All the studies demonstrated a reduction in sediment yield following gully rehabilitation, with reported values ranging between 12 and 94%. The timeframes associated with the reductions in sediment yield varied considerably (2–80 years). Applying a variety of rehabilitation measures, which generally includes treating both the hillslope above the gully, and trapping sediment within the gully, appears to result in shorter (median) timescales for sediment yield reduction. Overall, this review indicates that gully rehabilitation strategies combining both engineering and vegetation measures are often the most successful. Engineering measures such as check dams are important for stabilizing sites in the early phases to support the revegetation of gullies and adjacent hillslopes. However, vegetation is the key to the long‐term success of gully rehabilitation. This is because many engineering structures eventually fail, or they have a limited life span as an active sediment trap. © 2020 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Ltd

Collection, handling, fixation, and processing of Tammar Wallaby (Macropus eugenii) embryos

Publisher: Cold Spring Harbor Laboratory

Date: 12-2009

DOI: 10.1101/PDB.PROT5335

Abstract: This protocol describes methods for collecting and handling tammar wallaby (Macropus eugenii) conceptuses. Zygotes, cleavage stages, diapausing blastocysts, and unexpanded blastocysts are ~250 μm in diameter and are collected by flushing either the oviduct or uterus. Later stages are collected by opening the uterus. Late preimplantation stages must be handled carefully because their large size ( cm in diameter) results in high surface tension within the yolk sac, especially on the delicate avascular area. When handled too roughly, the embryonic vesicle tends to split and then rapidly collapse such embryos do not reinflate. If embryos are to be cultured, all steps during collection must be carried out aseptically. In all cases, solutions should be prewarmed to 37°C and embryos should be kept warm by use of a heating stage. Standard fixatives, fixation times, and washing protocols used for mouse embryos are also used for tammar embryos. Methods for embedding tammar conceptuses in paraffin wax depend on the size and stage of the conceptus.

Culturing Tammar Wallaby (Macropus eugenii) pouch young gonads

Publisher: Cold Spring Harbor Laboratory

Date: 12-2009

DOI: 10.1101/PDB.PROT5336

Abstract: Tammar wallaby (Macropus eugenii) pouch young (PY) gonads are ideal for studies on gonadal differentiation and germ cell proliferation because, in contrast to the mouse, both of these events occur postnatally in the tammar. In the male, testicular cords start developing at day 2 postpartum (pp), whereas in the female the ovarian cortex and medulla differentiate from ~day 8 pp. In females, meiosis starts from day 25 pp and is complete in most germ cells by day 50 pp. The gonads can be cultured either in grooves within agar or flat on a membrane. The former arrangement maintains the close contact of the gonad and mesonephros better than culturing them flat on a membrane. This protocol provides methods for isolation and culturing of PY gonads.

Performing surgery on Tammar Wallaby (Macropus eugenii) adults

Publisher: Cold Spring Harbor Laboratory

Date: 12-2009

DOI: 10.1101/PDB.PROT5333

Abstract: Adult tammar wallabies (Macropus eugenii) are very tolerant of surgery if it is conducted with care. Adult females weigh ~4‐5 kg, males ~7‐8 kg. Routine surgery performed in our laboratory and described in this protocol includes castration, laparotomy (to visualize the reproductive tract), ovariectomy, and hysterectomy (for embryo collection). All surgery is conducted under aseptic conditions. For most reproductive surgery on females, the optimum surgical approach is via the inside of the pouch. Any pouch young must be removed before surgery.

Identification of a novel antisense noncoding RNA, ALID, transcribed from the putative imprinting control region of marsupial IGF2R

Publisher: Springer Science and Business Media LLC

Date: 29-09-2018

DOI: 10.1186/S13072-018-0227-8

Surgery on Tammar Wallaby (Macropus eugenii) pouch young

Publisher: Cold Spring Harbor Laboratory

Date: 12-2009

DOI: 10.1101/PDB.PROT5334

Abstract: Two features of marsupial young make them ideal for developmental studies: (1) Their immune system, like that of the thyroid and thermoregulation, develops relatively late after birth, and (2) they tolerate xenografts. This late development allows transplants to grow and survive in the recipient for at least 150 d without the use of immunosuppressants. The immaturity of the organ systems and the tiny size of the neonate pose difficulties for anesthesia. However, because the pouch young are completely heterothermic until at least 3 mo of age, cooling can be used as an anesthetic agent. In practice, however, we use hypothermia for neonates and young up to the age of 25-30 d, and injectable anethetics thereafter. Healing is remarkably rapid. This tolerance of xenografts and the ability and ease with which hypothermia can be applied to marsupial young provides a unique approach to understanding developmental processes that normally take place in utero in eutherians. This protocol describes surgical procedures and post-surgical care performed on tammar wallaby (Macropus eugenii) pouch young (PY).

Yolk sac fluid and yolk sac membrane enzymes in the marsupial, Macropus eugenii

Publisher: Elsevier BV

Date: 10-1974

DOI: 10.1016/0305-0491(74)90161-8

Abstract: The South American country Chile now boasts a life expectancy of over 80 years. As a consequence, Chile now faces the increasing social and economic burden of cancer and must implement political policy to deliver equitable cancer care. Hindering the development of a national cancer policy is the lack of comprehensive analysis of cancer infrastructure and economic impact. Evaluate existing cancer policy, the extent of national investigation and the socio-economic impact of cancer to deliver guidelines for the framing of an equitable national cancer policy. Burden, research and care-policy systems were assessed by triangulating objective system metrics--epidemiological, economic, etc.--with political and policy analysis. Analysis of the literature and governmental databases was performed. The oncology community was interviewed and surveyed. Chile utilizes 1% of its gross domestic product on cancer care and treatment. We estimate that the economic impact as measured in Disability Adjusted Life Years to be US$ 3.5 billion. Persistent inequalities still occur in cancer distribution and treatment. A high quality cancer research community is expanding, however, insufficient funding is directed towards disproportionally prevalent stomach, lung and gallbladder cancers. Chile has a rapidly ageing population wherein 40% smoke, 67% are overweight and 18% abuse alcohol, and thus the corresponding burden of cancer will have a negative impact on an affordable health care system. We conclude that the Chilean government must develop a national cancer strategy, which the authors outline herein and believe is essential to permit equitable cancer care for the country.

The Evolution of Genomic Imprinting – A Marsupial Perspective

Publisher: Springer Netherlands

Date: 2010

DOI: 10.1007/978-90-481-9023-2_12

Pubertal development of the pouch and teats in the marsupial Macropus eugenii

Publisher: Bioscientifica

Date: 07-1994

DOI: 10.1530/JRF.0.1010279

Abstract: In the female tammar wallaby, Macropus eugenii, which has a highly seasonal breeding pattern, teat eversion and enlargement of the pouch occur at puberty, about 40 weeks after birth. The most obvious sign of puberty is teat eversion: 22 of 23 wild caught, and 23 of 24 captive postpubertal animals had fully everted or everting teats. Full eversion of the teats took on average two to three weeks after puberty. The pouch opening enlarged at puberty, and the rate of enlargement from 2 weeks before puberty to 2 weeks after puberty was significantly greater than the rate before puberty. In a group of pouch young ovariectomized at 5-10 weeks of age, no such changes in either teats or pouch were observed by 46 weeks of age. However, after treatment with oestradiol (0.5 microgram kg-1 body mass), four of five young showed teat eversion within 3-4 weeks. Progesterone (2 mg kg-1) had no effect on inverted teats. In these ovariectomized females oestradiol treatment caused a significant increase in the rate of growth of the pouch opening. During progesterone injections the size of the pouch remained the same. Thus, at puberty the teats and pouch of the tammar wallaby undergo rapid developmental changes and growth. Ovariectomy at an early stage of gonadal differentiation disrupts these normal changes, but treatment of these animals with physiological doses of oestradiol at the age when puberty would normally have occurred can restore teat and pouch maturation. Teat eversion and pouch enlargement can therefore be used as markers for puberty.(ABSTRACT TRUNCATED AT 250 WORDS)

Molecular Regulation of Marsupial Reproduction and Development

Publisher: Springer Netherlands

Date: 2010

DOI: 10.1007/978-90-481-9023-2_14

Effects of levonorgestrel on ovulation and oestrous behaviour in the female tammar wallaby

Publisher: CSIRO Publishing

Date: 2007

DOI: 10.1071/RD06063

Abstract: Subcutaneous hormone implants are a useful method for managing overabundant marsupials in restricted enclosures in Australia. Levonorgestrel induces long-term infertility in the kangaroo, tammar wallaby and koala, although the contraceptive mechanism of levonorgestrel is unknown for any marsupial. In the present study, it was investigated if insertion of a single levonorgestrel or control implant at the time of reactivation of the diapausing blastocyst affected the subsequent post-partum oestrus or the preceding follicular development. Twenty levonorgestrel-treated and 16 control animals were autopsied the day before birth and the accompanying post-partum oestrus (Day 25), and 10 levonorgestrel-treated and five of the nine control animals were autopsied 3–4 days (Days 29–30) after the expected birth and oestrus. Peripartum behaviour was observed and birth and mating times were recorded. Levonorgestrel treatment did not prevent follicular growth because there was no significant difference between treatment and control animals in the size of the dominant follicle at Day 25. None of the levonorgestrel-treated females autopsied at Days 29–30 had ovulated (n = 10), in contrast to controls, where four of the five that were autopsied had ovulated. Mating occurred in eight of nine control animals but in only three of 10 levonorgestrel-treated females. Males showed a more sustained period of interest in the three that were mated than in the controls, and mating took place significantly later after birth (36 v. 10 h P = 0.038). Follicular growth and development was not blocked in any female but only one-third of the animals mated and none ovulated after levonorgestrel treatment. These results suggest that levonorgestrel inhibits the preovulatory surge of luteinising hormone.

Identification of two distinct genes at the vertebrate TRPC2 locus and their characterisation in a marsupial and a monotreme

Publisher: Springer Science and Business Media LLC

Date: 19-08-2011

DOI: 10.1186/1471-2199-12-39

Abstract: The vomeronasal organ (VNO) detects pheromones via two large families of vomeronasal receptors: vomeronasal receptor 1 (V1R) and vomeronasal receptor 2 (V2R). Both VRs have a common receptor activation cascade involving transient receptor potential channel, subfamily C, member 2 (TRPC2). We characterised the TRPC2 locus in a marsupial, the tammar wallaby ( Macropus eugenii ), and identified two independently regulated genes not previously recognised as distinct. 3'-located exons comprise bona fide TRPC2 whilst 5'-located exons, previously identified as part of TRPC2 , comprise a distinct gene, which we term XNDR ( X RCC1 N -terminal d omain- r elated). The two genes show contrasting expression patterns in the tammar: TRPC2 is specifically expressed in adult and developing VNO, whereas XNDR is widely expressed in many tissues suggesting a non-VNO-specific role. Strong expression of TRPC2 was detected only after about day 30 post-partum, suggesting that the VNO may not be functional during early pouch life of the tammar. Similarly restricted expression of TRPC2 and widespread expression of XNDR was also detected in the platypus. Bioinformatic analysis of the genomes of a wide range of species suggests that the identity of XNDR and TRPC2 as distinct genes is conserved among vertebrates. Finally, we analysed the promoter of mammalian TRPC2 and identified a conserved binding site for NHLH1, a transcription factor previously implicated in VNO receptor neuron development. Two functionally distinct vertebrate genes- XNDR and TRPC2 - occupy a genomic locus that was previously defined as a single gene in the mouse. The former is widely expressed with a putative role in DNA repair, while the latter shows VNO-specific expression under the probable regulation of NHLH1.

The Comparative Physiology of Parturition in Mammals: Hormones and Parturition in Mammals

Publisher: Elsevier

Date: 2011

DOI: 10.1016/B978-0-12-374932-1.00053-6

FOXA1 and SOX9 Expression in the Developing Urogenital Sinus of the Tammar Wallaby <b><i>(Macropus eugenii)</i></b>

Publisher: S. Karger AG

Date: 2015

DOI: 10.1159/000439499

Abstract: The mammalian prostate is a compact structure in humans but multi-lobed in mice. In humans and mice, FOXA1 and SOX9 play pivotal roles in prostate morphogenesis, but few other species have been examined. We examined FOXA1 and SOX9 in the marsupial tammar wallaby, i Macropus eugenii /i , which has a segmented prostate more similar to human than to mouse. In males, prostatic budding in the urogenital epithelium (UGE) was initiated by day 24 postpartum (pp), but in the female the UGE remained smooth and had begun forming the marsupial vaginal structures. i FOXA1 /i was upregulated in the male urogenital sinus (UGS) by day 51 pp, whilst in the female UGS i FOXA1 /i remained basal. FOXA1 was localised in the UGE in both sexes between day 20 and 80 pp. i SOX9 /i was upregulated in the male UGS at day 21-30 pp and remained high until day 51-60 pp. SOX9 protein was localised in the distal tips of prostatic buds which were highly proliferative. The persistent upregulation of the transcription factors SOX9 and FOXA1 after the initial peak and fall of androgen levels suggest that in the tammar, as in other mammals, these factors are required to sustain prostate differentiation, development and proliferation as androgen levels return to basal levels.

The Evolution of the DLK1-DIO3 Imprinted Domain in Mammals

Publisher: Public Library of Science (PLoS)

Date: 03-06-2008

DOI: 10.1371/JOURNAL.PBIO.0060135

Author response: Transient role of the middle ear as a lower jaw support across mammals

Publisher: eLife Sciences Publications, Ltd

Date: 06-2020

DOI: 10.7554/ELIFE.57860.SA2

The functional development of Leydig cells in a marsupial

Publisher: Wiley

Date: 07-12-2007

DOI: 10.1111/J.1469-7580.2007.00837.X

The extension of mammalian pregnancy required taming inflammation; independent evolution of extended placentation in the tammar wallaby

Publisher: Cold Spring Harbor Laboratory

Date: 21-06-2023

DOI: 10.1101/2023.06.18.545206

Abstract: In the first live bearing mammals, it is assumed that pregnancy was short and ended with a brief period of inflammatory maternal-fetal interaction. This mode of reproduction has been retained in many marsupials. While inflammation is key to successful implantation in eutherians, a key innovation in eutherians is the ability to switch off this inflammation after it has been initiated. This extended period, in which inflammation is suppressed, likely allowed for an extended period of placentation. One lineage of marsupials, the macropodids (wallabies and kangaroos), have extended placentation beyond the 2-4 days seen in other marsupial taxa, which allows us to test whether a moderated inflammation response after attachment is a general pattern associated with the extension of placentation in mammals. We show that during tammar wallaby pregnancy, some inflammatory genes are expressed at key time points of gestation, including IL6 , before attachment, IL12A and LIF throughout the period of placentation and prostaglandins before birth. However, we did not see evidence of a complete inflammatory response at any time point. We argue that genes involved in a moderated inflammation reaction may have been co-opted into roles for placentation, facilitating the establishment and maintenance of extended fetal-maternal contact. Whilst the absence of other key mediators of inflammation may prevent prolonged damage to the uterus. We argue the moderation of inflammation following maternal-fetal contact is a convergently evolved key innovation that allowed for the extension of placentation in different mammalian lineages. Our data suggest that moderation of the inflammatory reaction to embryo attachment allows for extension of pregnancy in mammals. The ancestor of all mammals likely experienced an ancestral inflammatory reaction in response to embryo attachment. In contrast, eutherians and some marsupials, such as macropodids, have an extended period of fetal-maternal contact. During this period of placentation many inflammatory genes are silenced while a few others are still expressed. This moderated expression of inflammatory genes suggests that some genes of inflammation were coopted into establishing and maintaining the placenta. This challenges the perspective of inflammation as being detrimental to pregnancy, instead suggesting that fetal-maternal interactions are based on a modified inflammation response necessary for maintaining pregnancy over an extensive period of time.

Reproduction in Monotremes and Marsupials

Publisher: Wiley

Date: 30-05-2001

DOI: 10.1038/NPG.ELS.0001856

Early cell lineage specification in a marsupial: a case for diverse mechanisms among mammals

Publisher: The Company of Biologists

Date: 03-2013

DOI: 10.1242/DEV.091629

Abstract: Early cell lineage specification in eutherian mammals results in the formation of a pluripotent inner cell mass (ICM) and trophoblast. By contrast, marsupials have no ICM. Here, we present the first molecular analysis of mechanisms of early cell lineage specification in a marsupial, the tammar wallaby. There was no overt differential localisation of key lineage-specific transcription factors in cleavage and early unilaminar blastocyst stages. Pluriblast cells (equivalent to the ICM) became distinguishable from trophoblast cells by differential expression of POU5F1 and, to a greater extent, POU2, a paralogue of POU5F1. Unlike in the mouse, pluriblast-trophoblast differentiation coincided with a global nuclear-to-cytoplasmic transition of CDX2 localisation. Also unlike in the mouse, Hippo pathway factors YAP and WWTR1 showed mutually distinct localisation patterns that suggest non-redundant roles. NANOG and GATA6 were conserved as markers of epiblast and hypoblast, respectively, but some differences to the mouse were found in their mode of differentiation. Our results suggest that there is considerable evolutionary plasticity in the mechanisms regulating early lineage specification in mammals.

The composition of fetal fluids of the marsupial Macropus eugenii

Publisher: Elsevier BV

Date: 07-1973

DOI: 10.1016/0012-1606(73)90165-6

Abstract: Imaging the fields of magnetic materials provides crucial insight into the physical and chemical processes surrounding magnetism, and has been a key ingredient in the spectacular development of magnetic data storage. Existing approaches using the magneto-optic Kerr effect, x-ray and electron microscopy have limitations that constrain further development, and there is increasing demand for imaging and characterisation of magnetic phenomena in real time with high spatial resolution. Here we show how the magneto-optical response of an array of negatively-charged nitrogen-vacancy spins in diamond can be used to image and map the sub-micron stray magnetic field patterns from thin ferromagnetic films. Using optically detected magnetic resonance, we demonstrate wide-field magnetic imaging over 100 × 100 μm(2) with sub-micron spatial resolution at video frame rates, under ambient conditions. We demonstrate an all-optical spin relaxation contrast imaging approach which can image magnetic structures in the absence of an applied microwave field. Straightforward extensions promise imaging with sub-μT sensitivity and sub-optical spatial and millisecond temporal resolution. This work establishes practical diamond-based wide-field microscopy for rapid high-sensitivity characterisation and imaging of magnetic s les, with the capability for investigating magnetic phenomena such as domain wall and skyrmion dynamics and the spin Hall effect in metals.

Promoter-Specific Expression and Imprint Status of Marsupial IGF2

Publisher: Public Library of Science (PLoS)

Date: 25-07-2012

DOI: 10.1371/JOURNAL.PONE.0041690

Absence ofSOX3 in the developing marsupial gonad is not consistent with a conserved role in mammalian sex determination

Publisher: Wiley

Date: 2000

DOI: 10.1002/1526-968X(200008)27:4<145::AID-GENE30>3.0.CO;2-7

Primary genetic control of somatic sexual differentiation in a mammal

Publisher: Springer Science and Business Media LLC

Date: 02-1988

DOI: 10.1038/331716A0

Abstract: The classical view of mammalian sexual differentiation is that a gene on the Y chromosome transforms the indifferent gonad into a testis. The Leydig cells then secrete androgen which stimulates the development of the male reproductive tract, and the Sertoli cells secrete Mullerian inhibitory substance which inhibits the development of the female reproductive tract. In the absence of a testis, the Mullerian duct develops into the Fallopian tubes, uterus and vagina. Thus the whole of sexual differentiation is thought to be hormonally mediated as a consequence of this initial genetic determination of gonadal sex. We have found evidence in a marsupial mammal for extensive sexual dimorphisms which precede any morphological differentiation of the gonads. Thus the classical view of mammalian sexual differentiation may have over-emphasized the role of testicular hormones, and overlooked earlier genetic effects.

Sub-transducer element spatial resolution ultrasound wavefront modification using passive twin-layer compensators

Publisher: Elsevier BV

Date: 02-2018

DOI: 10.1016/J.APACOUST.2017.10.013

Recent Assembly of an Imprinted Domain from Non-Imprinted Components

Publisher: Public Library of Science (PLoS)

Date: 27-10-2006

DOI: 10.1371/JOURNAL.PGEN.0020182

Combining Ultrasound Pulse-Echo and Transmission Computed Tomography for Quantitative Imaging the Cortical Shell of Long-Bone Replicas

Publisher: Frontiers Media SA

Date: 29-11-2017

DOI: 10.3389/FMATS.2017.00040

Changes in semen quality and morphology of the reproductive tract of the male tammar wallaby parallel seasonal breeding activity in the female

Publisher: Bioscientifica

Date: 09-2005

DOI: 10.1530/REP.1.00538

Abstract: Changes in semen quality and morphology of the male reproductive tract were studied throughout the year in the highly promiscuous tammar wallaby. Body size, semen quality and gross morphology of the reproductive organs were assessed in adult males each month from January to November. The mean weight of males was similar in most periods s led, but males were slightly heavier in the minor ( P 0.05) than the non-breeding season. Since body weight was correlated with weights of the testes, epididymides and accessory sex glands, organ weights were adjusted for body weight in subsequent analyses. In the major breeding season (late January/early February), when most females go through a brief, highly synchronized oestrus, the testes, prostate, Cowper’s glands, crus penis and urethral bulb were heaviest, volume and coagulation of ejaculates were greatest, and sperm motility had increased. Semen s les collected by electroejaculation at this time contained low numbers of spermatozoa, possibly as a result of dilution and entrapment by the seminal coagulum or depletion of epididymal stores during intense multiple mating activity. In the non-breeding season (late May–July), when mating does not normally occur in the wild, there was a significant decrease in the relative weight of nearly all male reproductive organs and a decline in most semen parameters. In the minor breeding season (September–November), when pubertal females undergo their first oestrus and mating, the weights of testes, epididymides and most accessory sex glands had significantly increased similar to those of males in the major breeding season. The total number and motility of ejaculated spermatozoa were highest during this period, but the volume and coagulation of ejaculates and weight of the prostate had only increased to levels that were intermediate between the major and non-breeding seasons. Ejaculate volume was strongly correlated with prostate weight, and % motile spermatozoa was strongly correlated with epididymis weight. Semen quality thus varied seasonally with changes in androgen-dependent reproductive organs in the male tammar wallaby and appeared to be influenced by the seasonal timing of oestrus in females. Semen quality may also improve in response to an increase in the number of available oestrous females.

Fast Tessellated Solid Navigation in GEANT4

Publisher: Institute of Electrical and Electronics Engineers (IEEE)

Date: 08-2012

DOI: 10.1109/TNS.2012.2197415

Amsterdam positional OSA classification: the AASM 2012 recommended hypopnoea criteria increases the number of positional therapy candidates

Publisher: Springer Science and Business Media LLC

Date: 11-11-2017

DOI: 10.1007/S11325-016-1432-Y

Abstract: This study examined the effect of hypopnoea criteria on the prevalence of positional obstructive sleep apnoea (pOSA) identified under the Amsterdam Positional OSA Classification (APOC) system. Three hundred three consecutive patients undertaking polysomnography (PSG) for the suspicion of OSA were included in this retrospective investigation. PSGs were scored using both the 2007 American Academy of Sleep Medicine (AASM) recommended hypopnoea criteria (AASM The AASM This study demonstrates that, compared to AASM

Society for Reproductive Biology Founders' Lecture 2006 Life in the pouch: womb with a view

Publisher: CSIRO Publishing

Date: 2006

DOI: 10.1071/RD06072

Abstract: Marsupials give birth to an undeveloped altricial young after a relatively short gestation period, but have a long and sophisticated lactation with the young usually developing in a pouch. Their viviparous mode of reproduction trades placentation for lactation, exchanging the umbilical cord for the teat. The special adaptations that marsupials have developed provide us with unique insights into the evolution of all mammalian reproduction. Marsupials hold many mammalian reproductive ‘records’, for ex le they have the shortest known gestation but the longest embryonic diapause, the smallest neonate but the longest sperm. They have contributed to our knowledge of many mammalian reproductive events including embryonic diapause and development, birth behaviour, sex determination, sexual differentiation, lactation and seasonal breeding. Because marsupials have been genetically isolated from eutherian mammals for over 125 million years, sequencing of the genome of two marsupial species has made comparative genomic biology an exciting and important new area of investigation. This review will show how the study of marsupials has widened our understanding of mammalian reproduction and development, highlighting some mechanisms that are so fundamental that they are shared by all today’s marsupial and eutherian mammals.

Cooperativity of imprinted genes inactivated by acquired chromosome 20q deletions.

Publisher: American Society for Clinical Investigation

Date: 04-2013

DOI: 10.1172/JCI66113

Formation of 5α-reduced androgens in the testes and urogenital tract of the grey short-tailed opossum, Monodelphis domestica

Publisher: CSIRO Publishing

Date: 2009

DOI: 10.1071/RD08253

Abstract: Testicular 5α-reduced androgens, largely 5α-androstane-3α,17β-diol (androstanediol), are responsible for virilisation of pouch young in one marsupial (the tammar wallaby), but are not formed until later in development in another marsupial (the brushtail possum) and in rodents. Because the mechanism of virilisation of the urogenital tract in the grey short-tailed opossum Monodelphis domestica has never been defined, androgen formation and metabolism were investigated in this species. Testis fragments from grey short-tailed opossums of a wide range of ages were incubated with [3H]-progesterone and the metabolites were separated by high-performance liquid chromatography (HPLC). The only 19-carbon metabolites identified in the youngest ages (5–26 days) and the major metabolites in adult testes were testosterone and androstenedione. At 30, 42 and 49 days of age, dihydrotestosterone and small amounts of androstanediol were present. Time-sequence studies indicated that dihydrotestosterone and androstanediol were formed from the 5α-reduction (and 3-keto reduction) of testosterone. In a second series of experiments, tissue fragments of a variety of urogenital tract tissues were incubated with [3H]-testosterone and the metabolites separated by HPLC. During the interval in which male urogenital tract differentiation takes place in this species (between Days 15 and 28), the major metabolite identified was dihydrotestosterone. We conclude that the timing of 5α-reductase expression in the testes of the grey short-tailed possum resembles that of rodents and the brushtail possum rather than that of the tammar wallaby and that dihydrotestosterone is probably the intracellular androgen responsible for virilisation of the urogenital tract in this species.

Why menstruate?

Publisher: Wiley

Date: 14-12-2011

DOI: 10.1002/BIES.201190071

Measurement of a PAGAT gel dosimeter by ultrasound computed tomography

Publisher: IOP Publishing

Date: 26-06-2013

DOI: 10.1088/1742-6596/444/1/012083

Quantitative evaluation of polymer gel dosimeters by broadband ultrasound attenuation

Publisher: IOP Publishing

Date: 26-06-2013

DOI: 10.1088/1742-6596/444/1/012084

Bone volume fraction and structural parameters for estimation of mechanical stiffness and failure load of human cancellous bone samples; in-vitro comparison of ultrasound transit time spectroscopy and

Publisher: Elsevier BV

Date: 02-2018

DOI: 10.1016/J.BONE.2017.11.021

Abstract: Conventional mechanical testing is the 'gold standard' for assessing the stiffness (N mm

Initiation of development of diapausing embryo by mammary denervation during lactation in a marsupial

Publisher: Springer Science and Business Media LLC

Date: 04-1979

DOI: 10.1038/278549A0

Abstract: Apolipoprotein C-II (apoC-II) is a small protein found associated with the plasma lipoproteins. It serves a unique function in the activation of the enzyme lipoprotein lipase (triacylglycerol acyl-hydrolase, EC 3.1.1.3). ApoC-II contains a single arginine residue, permitting tryptic cleavage into two peptides after succinylation of the native protein. The succinylated amino-terminal peptide, approximately 50 residues, did not activate lipoprotein lipase. The succinylated carboxyl-terminal peptide, about 29 residues, had significant cofactor activity. Relative to native apoC-II, the maximal activation observed with the succinylated carboxyl-terminal peptide was 50% lower and the concentration required for half-maximal activity was approximately 10 times higher. Mixtures of the carboxyl- and amino-terminal peptides had no more activity than the carboxyl-terminal peptide alone. Localization of functional properties to the carboxyl region is a feature also common to apolipoproteins C-III, A-II, and A-I.

Reactivating tammar wallaby blastocysts oxidize glucose

Publisher: Oxford University Press (OUP)

Date: 06-1998

DOI: 10.1095/BIOLREPROD58.6.1425

Abstract: Metabolic reactivation of the tammar blastocyst appears to be characterized by a change in the pathway of glucose metabolism rather than an absolute increase in substrate uptake. The switch in type of metabolism used was examined to gain information on the timing and physiology of blastocyst reactivation. Fluorescent and radioisotope techniques were used sequentially to determine the activity of pathways of glucose metabolism by in idual wallaby blastocysts during diapause and 3, 4, 5, 6, 7, 8, and 10 days after removal of pouch young (RPY). Maternal endometrial and luteal cell metabolism and circulating hormone levels were measured and correlated with blastocyst activity. Observed differences between rates of blastocyst reactivation could be explained by variation in the maternal response between animals. While blastocysts recovered 4 days after RPY oxidized more glucose compared with Day 0 blastocysts (p < 0.05), rates of glycolysis did not change until Day 10. Blastocysts recovered between 4 and 10 days after RPY oxidized a significantly greater percentage of the glucose taken up (p < 0.01). The reduced ATP:ADP ratio within blastocysts recovered 3 days after RPY (p < 0.05) indicates that conditions are suitable for blastocysts to undergo a metabolic switch from glycolytic to oxidative metabolism of glucose on Day 4 after RPY. The increased oxidation results in greater ATP production, which plausibly fuels the increased energy requirements of wallaby blastocysts during the early stages of reactivation.

ARX/Arx is expressed in germ cells during spermatogenesis in both marsupial and mouse

Publisher: Bioscientifica

Date: 03-2014

DOI: 10.1530/REP-13-0361

Abstract: The X-linked aristaless gene, ARX , is essential for the development of the gonads, forebrain, olfactory bulb, pancreas, and skeletal muscle in mice and humans. Mutations cause neurological diseases, often accompanied by ambiguous genitalia. There are a disproportionately high number of testis and brain genes on the human and mouse X chromosomes. It is still unknown whether the X chromosome accrued these genes during its evolution or whether genes that find themselves on the X chromosome evolve such roles. ARX was originally autosomal in mammals and remains so in marsupials, whereas in eutherian mammals it translocated to the X chromosome. In this study, we examined autosomal ARX in tammars and compared it with the X-linked Arx in mice. We detected ARX mRNA in the neural cells of the forebrain, midbrain and hindbrain, and olfactory bulbs in developing tammars, consistent with the expression in mice. ARX was detected by RT-PCR and mRNA in situ hybridization in the developing tammar wallaby gonads of both sexes, suggestive of a role in sexual development as in mice. We also detected ARX/Arx mRNA in the adult testis in both tammars and mice, suggesting a potential novel role for ARX/Arx in spermiogenesis. ARX transcripts were predominantly observed in round spermatids. Arx mRNA localization distributions in the mouse adult testis suggest that it escaped meiotic sex chromosome inactivation during spermatogenesis. Our findings suggest that ARX in the therian mammal ancestor already played a role in male reproduction before it was recruited to the X chromosome in eutherians.

Seminiferous Cord Formation Is Regulated by Hedgehog Signaling in the Marsupial1

Publisher: Oxford University Press (OUP)

Date: 03-2012

DOI: 10.1095/BIOLREPROD.111.093070

Abstract: The signaling molecule DHH, secreted by Sertoli cells, has essential regulatory functions in testicular differentiation. DHH is required for the differentiation of peritubular myoid cells that line the seminiferous cords and steroidogenic Leydig cells. The testicular cords in Dhh-null male mice lack a basal lamina and develop abnormally. To date, the DHH-signaling pathway has never been examined outside of any eutherian mammals. This study examined the effects of inhibition of DHH signaling in a marsupial mammal, the tammar wallaby, by culturing gonads in vitro in the presence of the hedgehog-signaling inhibitors cyclopamine and forskolin. Disruption of hedgehog signaling in the tammar testes caused highly disorganized cord formation. SOX9 protein remained strongly expressed in Sertoli cells, laminin distribution was highly fragmented, and germ cells were distributed around the cortical regions of treated testes in an ovarianlike morphology. This suggests that hedgehog signaling regulates cord formation in the tammar wallaby testis as it does in eutherian mammals. These data demonstrate that the hedgehog pathway has been highly conserved in mammals for at least 160 million years.

Developmental expression of the androgen receptor during virilization of the urogenital system of a marsupial

Publisher: Oxford University Press (OUP)

Date: 10-1998

DOI: 10.1095/BIOLREPROD59.4.725

Abstract: In the marsupial tammar wallaby, virilization begins approximately 3 wk after the onset of testosterone synthesis. In the eutherian mammal, in contrast, the onset of virilization of the male urogenital tract occurs shortly after the onset of androgen synthesis. Androgen action requires the presence of the androgen receptor to mediate a response in target tissues. We therefore investigated the developmental expression of the androgen receptor (AR) in both sexes of the tammar wallaby. AR gene transcript was detected in fetal gonad and brain as early as Day 19 of the 26.5-day gestation, 7 days earlier than the first rise in testicular testosterone (Days 0-5 postpartum [p.p.]). Immunoreactive AR was identified in the male urogenital sinus (UGS) 2 days before birth and in the female UGS and mammary glands by the day of birth. AR was present in the UGS, vagina, and prostate until Day 152 p.p., the oldest age examined. AR was identified in the gubernaculum testis at Day 2 p.p. and became more abundant by Day 32. In the phallus of both sexes, AR was identified by Day 4 p.p. and until Day 157, the oldest age examined. AR was not detected in the scrotum at any age from the day of birth to Day 157. Maturation of the phallus, wolffian duct, and epididymis was marked by appearance of epithelial immunostaining. AR was localized in the epithelium of the UGS in females by Day 50 p.p. but was not found in the epithelium of the male UGS up to Day 152 p.p., the oldest examined. AR were found in the mesenchyme of the UGS of male and female tammars 3-4 wk before virilization is first evident in the male at Day 25 p.p. We conclude that the presence of AR is not the initiating signal for virilization of the UGS in this marsupial male.

An exploratory study on the use of enzyme activities as sediment tracers: biochemical fingerprints?

Publisher: Elsevier BV

Date: 06-2011

DOI: 10.1016/S1001-6279(11)60082-6

Freelance communications workers in the UK: the impact of gender on well‐being

Publisher: Emerald

Date: 09-2003

DOI: 10.1108/13563280310487649

Abstract: In an era when all workers are experiencing ever increasing stress levels, it may be anticipated that the move from traditional employment to freelance working would have a positive impact on the degree of occupational stress reported. In a recent UK survey of 190 freelance consultants (women n = 133 men n = 57) in the public relations and communications industry this expectation was indeed found to be supported. Over half of respondents stated that they were definitely less stressed than when they were employed and almost all reported that they were as healthy or healthier. The findings show that the positive benefits of freelance working for PR/communications consultants are significantly greater for women, who not only experience more health benefits than men, but also report significantly more improvements in their personal relationships and are significantly more satisfied with life.

Unsolved problems in male physiology: studies in a marsupial

Publisher: Elsevier BV

Date: 12-2003

DOI: 10.1016/J.MCE.2003.09.008

Abstract: Testicular androgens induce formation of the male urogenital tract in all mammals. In marsupials male development occurs after birth and over a prolonged period. For ex le, in the tammar wallaby virilization of the Wolffian ducts begins by day 20, prostate formation begins about day 25, and phallic development starts after day 80 of pouch life. Between days 20 and 40 5alpha-androstane-3alpha,17beta-diol (5alpha-adiol) is formed in tammar testes and secreted into plasma. Administration of 5alpha-adiol to pouch young females induces urogenital sinus virilization by day 40 and formation of a mature male prostate and phallus by day 150. 5alpha-Adiol is synthesized in pouch young testes by two pathways, one involving testosterone and dihydrotestosterone and the other 5alpha-pregnane-3alpha,17alpha-diol-20-one and androsterone as intermediates, both utilizing steroid 5alpha-reductase. In target tissues 5alpha-adiol acts via the androgen receptor after conversion to dihydrotestosterone but may have other actions as well. Whether 5alpha-adiol plays a role in male development in placental mammals is uncertain.

A deconvolution method for deriving the transit time spectrum for ultrasound propagation through cancellous bone replica models

Publisher: SAGE Publications

Date: 05-03-2014

DOI: 10.1177/0954411914523582

Abstract: The acceptance of broadband ultrasound attenuation for the assessment of osteoporosis suffers from a limited understanding of ultrasound wave propagation through cancellous bone. It has recently been proposed that the ultrasound wave propagation can be described by a concept of parallel sonic rays. This concept approximates the detected transmission signal to be the superposition of all sonic rays that travel directly from transmitting to receiving transducer. The transit time of each ray is defined by the proportion of bone and marrow propagated. An ultrasound transit time spectrum describes the proportion of sonic rays having a particular transit time, effectively describing lateral inhomogeneity of transit times over the surface of the receiving ultrasound transducer. The aim of this study was to provide a proof of concept that a transit time spectrum may be derived from digital deconvolution of input and output ultrasound signals. We have applied the active-set method deconvolution algorithm to determine the ultrasound transit time spectra in the three orthogonal directions of four cancellous bone replica s les and have compared experimental data with the prediction from the computer simulation. The agreement between experimental and predicted ultrasound transit time spectrum analyses derived from Bland–Altman analysis ranged from 92% to 99%, thereby supporting the concept of parallel sonic rays for ultrasound propagation in cancellous bone. In addition to further validation of the parallel sonic ray concept, this technique offers the opportunity to consider quantitative characterisation of the material and structural properties of cancellous bone, not previously available utilising ultrasound.

Inducing sex reversal of the urogenital system of marsupials

Publisher: Elsevier BV

Date: 2014

DOI: 10.1016/J.DIFF.2013.11.003

Abstract: Marsupials differ from eutherian mammals in their reproductive strategy of delivering a highly altricial young after a short gestation. The young, with its undeveloped organ systems completes its development post-natally, usually within a pouch. The young is dependent on milk with a composition that varies through lactation to support its growth and changing needs as it matures over a lengthy period. Gonadal differentiation occurs after birth, providing a unique opportunity to examine the effects of hormonal manipulations on its sexual differentiation of the highly accessible young. In marsupials a difference in the migration of the urinary ducts around the genital ducts from eutherian mammals results in the unique tammar reproductive tract which has three vaginae and two cervices, and two distinctly separate uteri. In the tammar wallaby, a small member of the kangaroo family, we showed that virilisation of the Wolffian duct, prostate and phallus depends on an alternate androgen pathway, which has now been shown to be important for virilisation in humans. Through hormonal manipulations over differing time periods we have achieved sex reversal of both ovaries and testes, germ cells, genital ducts, prostate and phallus. Whilst we understand many of the mechanisms behind sexual differentiation there are still many lessons to be learned from understanding how sex reversal is achieved by using a model such as the tammar wallaby. This will help guide investigations into the major questions of how and why sex determination is achieved in other species. This review discusses the control and development of the marsupial urogenital system, largely drawn from our studies in the tammar wallaby and our ability to manipulate this system to induce sex reversal.

The origin and evolution of genomic imprinting and viviparity in mammals

Publisher: The Royal Society

Date: 05-01-2013

DOI: 10.1098/RSTB.2012.0151

Abstract: Genomic imprinting is widespread in eutherian mammals. Marsupial mammals also have genomic imprinting, but in fewer loci. It has long been thought that genomic imprinting is somehow related to placentation and/or viviparity in mammals, although neither is restricted to mammals. Most imprinted genes are expressed in the placenta. There is no evidence for genomic imprinting in the egg-laying monotreme mammals, despite their short-lived placenta that transfers nutrients from mother to embryo. Post natal genomic imprinting also occurs, especially in the brain. However, little attention has been paid to the primary source of nutrition in the neonate in all mammals, the mammary gland. Differentially methylated regions (DMRs) play an important role as imprinting control centres in each imprinted region which usually comprises both paternally and maternally expressed genes ( PEG s and MEG s). The DMR is established in the male or female germline (the gDMR). Comprehensive comparative genome studies demonstrated that two imprinted regions, PEG10 and IGF2-H19 , are conserved in both marsupials and eutherians and that PEG10 and H19 DMRs emerged in the therian ancestor at least 160 Ma, indicating the ancestral origin of genomic imprinting during therian mammal evolution. Importantly, these regions are known to be deeply involved in placental and embryonic growth. It appears that most maternal gDMRs are always associated with imprinting in eutherian mammals, but emerged at differing times during mammalian evolution. Thus, genomic imprinting could evolve from a defence mechanism against transposable elements that depended on DNA methylation established in germ cells.

5th International Symposium on Physiology, Behaviour and Conservation of Wildlife, Berlin 2004

Publisher: Wiley

Date: 09-2004

DOI: 10.1111/J.1439-0310.2004.11038.X

Structure of the pars distalis in pouch-young tammar wallabies (Macropus eugenii)

Publisher: Springer Science and Business Media LLC

Date: 04-1983

DOI: 10.1007/BF00216203

Abstract: To improve the quality of whole soybean curd (WSC), effects of compound coagulants consisting of calcium chloride (CaCl

Evolution of the CDKN1C-KCNQ1 imprinted domain

Publisher: Springer Science and Business Media LLC

Date: 29-05-2008

DOI: 10.1186/1471-2148-8-163

Abstract: Genomic imprinting occurs in both marsupial and eutherian mammals. The CDKN1C and IGF2 genes are both imprinted and syntenic in the mouse and human, but in marsupials only IGF2 is imprinted. This study examines the evolution of features that, in eutherians, regulate CDKN1C imprinting. Despite the absence of imprinting, CDKN1C protein was present in the tammar wallaby placenta. Genomic analysis of the tammar region confirmed that CDKN1C is syntenic with IGF2 . However, there are fewer LTR and DNA elements in the region and in intron 9 of KCNQ1 . In addition there are fewer LINEs in the tammar compared with human and mouse. While the CpG island in intron 10 of KCNQ1 and promoter elements could not be detected, the antisense transcript KCNQ1OT1 that regulates CDKN1C imprinting in human and mouse is still expressed. CDKN1C has a conserved function, likely antagonistic to IGF2, in the mammalian placenta that preceded its acquisition of imprinting. CDKN1C resides in synteny with IGF2, demonstrating that imprinting of the two genes did not occur concurrently to balance maternal and paternal influences on the growth of the placenta. The expression of KCNQ1OT1 in the absence of CDKN1C imprinting suggests that antisense transcription at this locus preceded imprinting of this domain. These findings demonstrate the stepwise accumulation of control mechanisms within imprinted domains and show that CDKN1C imprinting cannot be due to its synteny with IGF2 or with its placental expression in mammals.

Sexual Differentiation in Marsupials

Publisher: Springer US

Date: 1987

DOI: 10.1007/978-1-4899-1965-6_3

Fibroblast growth factor-9 in marsupial testicular development

Publisher: S. Karger AG

Date: 2011

DOI: 10.1159/000327327

Abstract: FGF9 is a member of the fibroblast growth factor (FGF) family and is critical for early testicular development and germ cell survival in the mouse. i Fgf9 /i reinforces the testis determinant i Sox9 /i and antagonizes i Wnt4 /i , an ovarian factor. To determine whether i FGF9 /i has a conserved role in the mammalian gonad, we examined its expression in the gonads of a marsupial, the tammar wallaby i Macropus eugenii, /i and compared it to i WNT4 /i expression. Marsupial i FGF9 /i is highly conserved with orthologues from eutherian mammals, including humans. FGF9 protein was detected in both the testis and ovary before sexual differentiation, but it subsequently became sexually dimorphic during the period of testicular differentiation. The protein was specifically enriched in the seminiferous cords of the developing testis in the Sertoli and germ cells. i FGF9 /i mRNA expression was upregulated in the tammar testis at the time of seminiferous cord formation and downregulated in the developing ovary in an opposite profile to that of marsupial i WNT4 /i . These observations suggest that i FGF9 /i promotes male fate in the early gonad of marsupials through an antagonistic relationship with i WNT4 /i as it does in eutherian mammals.

Primary Genetic-Control of Sexual-Differentiation in Marsupials

Publisher: CSIRO Publishing

Date: 1989

DOI: 10.1071/ZO9890443

Abstract: Marsupials, like eutherians, normally require the presence of a Y chromosome for testicular formation. However some sexually dimorphic characters such as the scrotum, mammary anlagen, gubernaculum and processus vaginalis appear to be under direct genetic rather than secondary hormonal control. Scrota1 development occurs where only a single X chromosome is functional, whilst two X chromosomes are necessary for pouch formation.

5α-Androstane-3α,17β-Diol Is Formed in Tammar Wallaby Pouch Young Testes by a Pathway Involving 5α-Pregnane-3α,17α-Diol-20-One as a Key Intermediate

Publisher: The Endocrine Society

Date: 02-2003

DOI: 10.1210/EN.2002-220721

Abstract: The synthetic pathway by which 5α-androstane-3α,17β-diol (5α-adiol) is formed in the testes of tammar wallaby pouch young was investigated by incubating testes from d 20–40 males with various radioactive precursors and analyzing the metabolites by thin-layer chromatography and HPLC. [3H]Progesterone was converted to 17-hydroxyprogesterone, which was converted to 5α-adiol by two pathways: One involves the formation of testosterone and dihydrotestosterone as intermediates, and the other involves formation of 5α-pregnane-3α,17α-diol-20-one (5α-pdiol) and androsterone as intermediates. Formation of 5α-adiol from both [3H]testosterone and [3H]progesterone was blocked by the 5α-reductase inhibitor 4MA. The addition of nonradioactive 5α-pdiol blocked the conversion of [3H]progesterone to 5α-adiol, and [3H]5α-pdiol was efficiently converted to androsterone and 5α-adiol. We conclude that expression of steroid 5α-reductase in the developing wallaby testes allows formation of 5α-reduced androgens by a pathway that does not involve testosterone as an intermediate.

Limited Genetic Diversity Preceded Extinction of the Tasmanian Tiger

Publisher: Public Library of Science (PLoS)

Date: 18-04-2012

DOI: 10.1371/JOURNAL.PONE.0035433

Expression of DMRT1 in the mammalian ovary and testis – from marsupials to mice

Publisher: S. Karger AG

Date: 2003

DOI: 10.1159/000074342

Abstract: Doublesex and mab3 related transcript (DMRT1) was identified as a candidate gene for human 9p24.3 associated sex reversal. DMRT1 orthologues have highly conserved roles in sexual differentiation from flies and worms to humans. A DMRT1 orthologue was isolated from a marsupial, the tammar wallaby i Macropus eugenii /i . The wallaby gene is highly conserved with other vertebrate DMRT1 genes, especially within the P/S and DM domains. It is expressed in the differentiating testis from the late fetus, during pouch life and in the adult. As in eutherian mammals, DMRT1 protein was localized in the germ cells and the Sertoli cells of the testis, but in addition it was detected in the Leydig cells, peri-tubular myoid cells and within the acrosome of the sperm heads. DMRT1 protein was also detected in the fetal and adult ovary pre-granulosa, granulosa and germ cells. Similarly, we also detected DMRT1 in the granulosa cells of all developing follicles in the adult mouse ovary. This is the first report of DMRT1 expression in the adult mammalian ovary, and suggests a wider role for this gene in mammals, in both the testis and ovarian function.

Genomic imprinting of IGF2, p57 and PEG1/MEST in a marsupial, the tammar wallaby

Publisher: Elsevier BV

Date: 02-2005

DOI: 10.1016/J.MOD.2004.10.003

Abstract: Genomic imprinting is widespread amongst mammals, but has not yet been found in birds. To gain a broader understanding of the origin and significance of imprinting, we have characterized three genes, from three separate imprinted clusters in eutherian mammals in the developing fetus and placenta of an Australian marsupial, the tammar wallaby Macropus eugenii. Imprinted gene orthologues of human and mouse p57(KIP2), IGF2 and PEG1/MEST genes were isolated. p57(KIP2) did not show stable monoallelic expression suggesting that it is not imprinted in marsupials. In contrast, there was paternal-specific expression of IGF2 in almost all tissues, but the biased paternal expression of IGF2 in the fetal head and placenta, demonstrates the occurrence of tissue-specific imprinting, as occurs in mice and humans. There was also paternal-biased expression of PEG1/MESTalpha. The differentially methylated region (DMR) of the human and mouse PEG1/MEST promoter is absent in the wallaby. These data confirm the existence of common imprinted regions in eutherians and marsupials during development, but suggest that the regulatory mechanisms that control imprinted gene expression differ between these two groups of mammals.

The fetomaternal interface shows vascular hypoglycosylation in the tammar wallaby Macropus eugenii: Comparison with a range of non-mammalian and eutherian placentae

Publisher: Elsevier BV

Date: 10-2013

DOI: 10.1016/J.PLACENTA.2013.07.004

Abstract: Blood vessel glycosylation at the fetomaternal interface of four near-term specimens of tammar wallaby, Macropus eugenii, has been examined at days 23-26 of the 26.5 day pregnancy and compared with that of other species. A panel of 23 lectins was used to compare vasculature in tammar with non-mammalian (shark, skink) and eutherian species at early and late gestation (camel, horse and alpaca), and term/near-term (cat, lion, dog, mink and elephant). Strikingly low levels of all the glycans tested, apart from sialic acids, were found in capillary endothelium of both the trilaminar omphalopleure and underlying surface endometrium of the tammar, though deeper endometrial vessels showed normally high levels of glycosylation. Only maternal vasculature of the mink placenta showed a comparable lack of expression. One reason for a reduced endothelial glycocalyx may be to facilitate diffusion of gases and nutrients as the tammar trophoblast lacks the indentation by overlying vessels that is seen in the other near-term placentae. Early epitheliochorial placentae of other species with equal diffusion distances to the tammar, showed normal vascular glycosylation. However, their pregnancies are much longer. The hypoglycosylation of tammar vessels at the fetomaternal interface may allow continued transfer of nutrients and gaseous exchange during the extremely rapid period of organogenesis which occurs during the short 26.5 day pregnancy of this marsupial. Given the short gestation period of the tammar, we suggest that a thinner endothelial glycocalyx has evolved to facilitate diffusion of gases and nutrients between the maternal and fetal compartments.

Effects of bromocriptine at parturition in the tammar wallaby, Macropus eugenii

Publisher: CSIRO Publishing

Date: 1990

DOI: 10.1071/RD9900079

Abstract: Female tammar wallabies were treated with the dopamine agonist bromocriptine at the end of pregnancy to suppress the peripartum pulse of plasma prolactin. The animals were subsequently observed, and a series of blood s les taken to define the hormonal profiles before and immediately after parturition. Birth was observed in 4/5 control animals and occurred in 8/9 bromocriptine-treated animals. The peripartum peak in plasma PGFM concentrations was not affected by bromocriptine although the pulse of prolactin normally seen at parturition was completely abolished. The timing of luteolysis was apparently unaffected, as plasma progesterone concentrations fell similarly in both treated and control animals immediately after parturition. However, all of the neonates of the bromocriptine-treated animals died within 24 h, possibly because of a failure to establish lactation. Subsequent onset of post-partum oestrus was delayed or absent both in control and in bromocriptine-treated animals, suggesting that the frequent blood s ling and disturbances in the peripartum period interfered with these endocrine processes. It is concluded that both prolactin and prostaglandin can induce luteolysis in the pregnant wallaby, but that the normal sequence of events results from a signal of fetal origin inducing a prostaglandin release from the uterus, which in turn releases a pulse of prolactin that induces a progesterone decline.

Evidence for a local fetal influence on myometrial oxytocin receptors during pregnancy in the tammar wallaby (Macropus eugenii)

Publisher: Oxford University Press (OUP)

Date: 1997

DOI: 10.1095/BIOLREPROD56.1.200

Abstract: Mesotocin (MT), the oxytocin-like peptide of the tammar wallaby (Macropus eugenii) is important for delivery of live young. The tammar mesotocin receptor (MTR) was first characterized using the iodinated oxytocin receptor antagonist [125I]d(CH2)5 [Tyr(Me)2, Tyr4, Orn8, Tyr-NH(2)9]-vasotocin. MTR concentrations were then measured in matched s les of gravid and nongravid myometrium and median vagina at different stages of the 26-day pregnancy. MTR concentrations in both the gravid and nongravid myometrium changed significantly (ANOVA, p < 0.01) during pregnancy. There was no difference in MTR concentrations between uteri on Days 8-22. From Day 23 of pregnancy, MTR concentrations in the gravid myometrium increased (615.8 +/- 144.0 fmol/mg protein), whereas in the nongravid myometrium, they remained unchanged (248.6 +/- 65.5 fmol/mg protein). Receptor concentrations were high in the gravid myometrium during the last 3 days of pregnancy but decreased significantly in the nongravid myometrium. In the median vagina, MTR concentrations were low compared with myometrial tissues and did not increase at term. Changes in MTR concentrations paralleled changes in uterine responsiveness to exogenous MT in vitro. Our data show that MTR concentrations and the responsiveness to MT differ between the gravid and nongravid myometrium during pregnancy. The increase in MTRs in the gravid myometrium and the decrease in the nongravid suggest that different factors influence these receptors in the separate uteri, independent of systemic influence.

Ultrastructural localization of relaxin in the corpus luteum of the pregnant and early lactating tammar wallaby, Macropus eugenii

Publisher: Springer Science and Business Media LLC

Date: 26-11-1997

DOI: 10.1007/S004410050967

Abstract: Electron-microscope immunocytochemistry was used to determine the subcellular distribution and presence of immunoreactive relaxin throughout pregnancy and early lactation in the corpus luteum of a marsupial, the tammar wallaby. Membrane-bound, electron-dense granules were a prominent feature of the luteal cell cytoplasm. The highest numbers of granules were observed between days 20 and 24 of the 26-day gestation, with a rapid clearance immediately after birth. Relaxin immunogold particles were present only in small, electron-dense granules (200-350 nm in diameter), with no particles observed in larger granules (>400 nm diameter), nuclei or mitochondria. Relaxin immunoreactivity was low throughout early and mid pregnancy but increased markedly between days 21 and 22 and remained high over the last 4 days of pregnancy. The number of granules containing relaxin immunogold particles and the density of immunostaining were both reduced on the day of expected births (day 26). Our data demonstrate that electron-dense granules in the luteal cell cytoplasm of a pregnant marsupial contain relaxin. The peptide is produced in greatest amounts at the end of pregnancy, consistent with a role in parturition.

Manipulation of Marsupial Embryos and Pouch Young

Publisher: Elsevier

Date: 1978

DOI: 10.1016/B978-0-12-201850-3.50020-6

Experimental and computer simulation validation of ultrasound phase interference created by lateral inhomogeneity of transit time in replica bone: marrow composite models

Publisher: SAGE Publications

Date: 26-04-2013

DOI: 10.1177/0954411913486079

Abstract: The measurement of broadband ultrasound attenuation in cancellous bone for the assessment of osteoporosis follows a parabolic-type dependence with bone volume fraction, having minima values corresponding to both entire bone and entire marrow. Langton has recently proposed that the primary attenuation mechanism is phase interference due to variations in propagation transit time through the test s le as detected over the phase-sensitive surface of the receive ultrasound transducer. This fundamentally simple concept assumes that the propagation may be considered as an array of parallel ‘sonic rays’. The transit time of each ray is defined by the proportion of bone and marrow propagated, being a minimum (t min ) solely through bone and a maximum (t max ) solely through marrow, from which a transit time spectrum, may be defined describing the proportion of sonic rays having a particular transit time. The aim of this study was to test the hypothesis that there is a dependence of phase interference upon the lateral inhomogeneity of transit time by comparing experimental measurements and computer simulation predictions of ultrasound propagation through a range of relatively simplistic solid:liquid models. From qualitative and quantitative comparison of the experimental and computer simulation results, there is an extremely high degree of agreement of 94.2%–99.0% between the two approaches. This combined experimental and computer simulation study has successfully demonstrated that lateral inhomogeneity of transit time has significant potential for phase interference to occur if a phase-sensitive receive ultrasound transducer is implemented as in most commercial ultrasound bone analysis devices.

Identification of tammar wallaby SIRH12, derived from a marsupial-specific retrotransposition event

Publisher: Oxford University Press (OUP)

Date: 02-06-2011

DOI: 10.1093/DNARES/DSR012

Exercise and ectopic fat in type 2 diabetes: A systematic review and meta-analysis

Publisher: Elsevier BV

Date: 06-2017

DOI: 10.1016/J.DIABET.2016.12.006

Abstract: Ectopic adipose tissue surrounding the intra-abdominal organs (visceral fat) and located in the liver, heart, pancreas and muscle, is linked to cardio-metabolic complications commonly experienced in type 2 diabetes. A systematic review and meta-analysis was performed to determine the effect of exercise on ectopic fat in adults with type 2 diabetes. Relevant databases were searched to February 2016. Included were randomised controlled studies, which implemented≥4 weeks of aerobic and/or resistance exercise and quantified ectopic fat via magnetic resonance imaging, computed tomography, proton magnetic resonance spectroscopy or muscle biopsy before and after intervention. Risk of bias and study quality was assessed using Egger's funnel plot test and modified Downs and Black checklist, respectively. Of the 10,750 studies retrieved, 24 were included involving 1383 participants. No studies were found assessing the interaction between exercise and cardiac or pancreas fat. One study assessed the effect of exercise on intramyocellular triglyceride concentration. There was a significant pooled effect size for the meta-analysis comparing exercise vs. control on visceral adiposity (ES=-0.21, 95% CI: -0.37 to -0.05 P=0.010) and a near-significant pooled effect size for liver steatosis reduction with exercise (ES=-0.28, 95% CI: -0.57 to 0.01 P=0.054). Aerobic exercise (ES=-0.23, 95% CI: -0.44 to -0.03 P=0.025) but not resistance training exercise (ES=-0.13, 95% CI: -0.37 to 0.12 P=0.307) was effective for reducing visceral fat in overweight/obese adults with type 2 diabetes. These data suggest that exercise effectively reduces visceral and perhaps liver adipose tissue and that aerobic exercise should be a key feature of exercise programs aimed at reducing visceral fat in obesity-related type 2 diabetes. Further studies are required to assess the relative efficacy of exercise modality on liver fat reduction and the effect of exercise on pancreas, heart, and intramyocellular fat in type 2 diabetes and to clarify the effect of exercise on ectopic fat independent of weight loss.

Reproductive Physiology of Marsupials

Publisher: Cambridge University Press

Date: 30-01-1987

DOI: 10.1017/CBO9780511623493

Abstract: Marsupials differ from most other mammals in their method of reproduction, in that they have chosen, in an evolutionary sense, to develop lactation rather than placentation for the nurture of their young. The neonate is therefore born with a mixture of advanced and embryonic characters, and yet is readily accessible within the pouch, providing a unique system for the study of the ontogeny of various physiological and endocrinological parameters. Marsupials are therefore ideal animals for research into mammalian reproductive physiology. The results of this exciting new research are summarized in this book by two of the foremost workers in the field. In idual chapters analyse the genetic and hormonal control of sexual differentiation, male and female reproductive structures and their functions, the role of the corpus luteum in the oestrous cycle and pregnancy, the hormonal control of embryonic diapause and the role of the marsupial placenta in the development of the embryo. This book is more than just a straightforward review of marsupial reproduction for its detailed analyses and broad comparative coverage will attract mammalogists and reproductive physiologists with a wide range of research interests.

Ovarian steroid metabolism and oestrogens in the corpus luteum of the tammar wallaby

Publisher: Bioscientifica

Date: 05-1984

DOI: 10.1677/JOE.0.1010231

Abstract: Ovaries were obtained from tammar wallabies at various stages of the reproductive cycle to examine the occurrence of oestrogens in corpora lutea, and the synthesis and metabolism of steroids in the corpus luteum and ovarian cortical and interstitial tissues. Corpora lutea contained oestradiol-17β and oestrone during embryonic diapause and at all stages of pregnancy studied after blastocyst activation. Aryl sulphatase, 3β-hydroxysteroid dehydrogenase and 17β-oxidoreductase were shown to be present in luteal and other ovarian tissues by incubation in vitro with labelled substrates. Aromatase was undetectable in corpora lutea or in interstitial tissue, but was present in the ovarian tissues (including follicles) which remained after removal of corpora lutea. The probable source of the oestrogens detected in the corpus luteum is discussed in relation to their role in the inhibition of follicular development during embryonic diapause. J. Endocr. (1984) 101 , 231–240

Structure of the pars distalis in the adult tammar wallaby (Macropus eugenii)

Publisher: Springer Science and Business Media LLC

Date: 1983

DOI: 10.1007/BF00217888

Abstract: Organ preserving surgery (OPS) and radiotherapy (RT) are both accepted treatment options for early stage supraglottic cancer (SGC). Radiation has supplanted surgery in most cases, because of the perception that surgery results in poorer functional outcomes. However, evidence suggests that OPS with a neck dissection may be associated with improved survival. Our objective was to conduct a systematic review of the literature to compare functional outcomes of OPS and RT for early SGC. We searched Medline, EMBASE and Cochrane Central Register of Controlled Trials to identify studies. Studies were included if they reported functional outcomes on 10 or more patients with early stage SGC treated with radiation or OPS, including open partial laryngectomy, transoral laser microsurgery (TLM) or transoral robotic surgery (TORS). Two reviewers independently screened articles for relevance using pre-determined criteria. From 7720 references, we included 10 articles (n = 640 patients). 50% (n = 320) of patients were treated with surgery. Three head-to-head RT versus OPS papers were included, however different outcome measures were used for each group. Intractable aspiration management (including total laryngectomy or permanent tracheostomy) following OPS was reported in five papers representing 186 patients the definitive intractable aspiration management rate was 2.6% (95% CI 1.0-6.8%). Four papers reported permanent G-tube rate for the surgical group (n = 198), calculating a rate of 5.3% (95% CI 2.6-10.5%), this was not reported for the RT group in any papers. One study reported quality of life. Two studies reported objective voice measures. This systematic review revealed a paucity of objective measures and significant data heterogeneity, rendering the comparison of functional outcomes following OPS versus RT for early SGC limited. Future research should include objective measures of functional outcomes including laryngectomy rate, g-tube rate, tracheostomy dependence, quality of life, and voice quality measures.

Perturbed growth and development in marsupial young after reciprocal cross-fostering between species

Publisher: CSIRO Publishing

Date: 2007

DOI: 10.1071/RD07142

Abstract: Cross-fostering of marsupial young between species can potentially facilitate propagation of endangered or rare marsupial species by artificially increasing the number of progeny produced. The present study compares the growth and development of normal and cross-fostered tammar and parma wallabies. Tammars cross-fostered into the pouches of parmas grew at a similar rate to naturally reared tammar young and had developmental milestones at a similar age. However, parma young cross-fostered between the day of birth and 15 days post-partum into tammars that were carrying young of equivalent developmental stages did not grow normally and were lost from the pouch. Parma young cross-fostered at 30 days survived, but had significantly reduced growth rates and their developmental milestones were delayed compared with normally reared parma young. Thus, growth can be affected by cross-fostering, even between species like tammars and parmas that are of similar size and have similar lactation lengths. The results of the present study suggest that maternal milk regulates the timing of development of each species and a mis-match in the time that each young receives critical milk components can have a marked effect on their growth and development.

Genomic imprinting in marsupial placentation

Publisher: Bioscientifica

Date: 11-2008

DOI: 10.1530/REP-08-0264

Abstract: Genomic imprinting is a widespread epigenetic phenomenon in eutherian mammals, which regulates many aspects of growth and development. Parental conflict over the degree of maternal nutrient transfer is the favoured hypothesis for the evolution of imprinting. Marsupials, like eutherian mammals, are viviparous but deliver an altricial young after a short gestation supported by a fully functional placenta, so can shed light on the evolution and time of acquisition of genomic imprinting. All orthologues of eutherian imprinted genes examined have a conserved expression in the marsupial placenta regardless of their imprint status. Differentially methylated regions (DMRs) are the most common mechanism controlling genomic imprinting in eutherian mammals, but none were found in the marsupial imprinted orthologues of IGF2 receptor ( IGF2R ), INS or mesoderm-specific transcript ( MEST ). Instead, histone modification appears to be the mechanism used to silence these genes. At least three genes in marsupials have DMRs: H19 , IGF2 and PEG10 . PEG10 is particularly interesting as it is derived from a retrotransposon, providing the first direct evidence that retrotransposon insertion can drive the evolution of an imprinted region and of a DMR in mammals. The insertion occurred after the prototherian–therian mammal ergence, suggesting that there may have been strong selection for the retention of imprinted regions that arose during the evolution of placentation. There is currently no evidence for genomic imprinting in the egg-laying monotreme mammals. However, since these mammals do have a short-lived placenta, imprinting appears to be correlated with viviparity but not placentation.

Retrospective evaluation of dosimetric quality for prostate carcinomas treated with 3D conformal, intensity modulated and volumetric modulated arc radiotherapy

Publisher: Wiley

Date: 19-11-2013

DOI: 10.1002/JMRS.24

Abolition of seasonal embryonic diapause in a wallaby by pineal denervation

Publisher: Springer Science and Business Media LLC

Date: 09-1981

DOI: 10.1038/293138A0

Growth axis maturation is linked to nutrition, growth and developmental rate

Publisher: Elsevier BV

Date: 08-2015

DOI: 10.1016/J.MCE.2015.04.009

Abstract: Maturation of the mammalian growth axis is thought to be linked to the transition from fetal to post-natal life at birth. However, in an altricial marsupial, the tammar wallaby (Macropus eugenii), this process occurs many months after birth but at a time when the young is at a similar developmental stage to that of neonatal eutherian mammals. Here we manipulate growth rates and demonstrate in slow, normal and fast growing tammar young that nutrition and growth rate affect the time of maturation of the growth axis. Maturation of GH/IGF-I axis components occurred earlier in fast growing young, which had significantly increased hepatic GHR, IGF1 and IGFALS expression, plasma IGF-I concentrations, and significantly decreased plasma GH concentrations compared to age-matched normal young. These data support the hypothesis that the time of maturation of the growth axis depends on the growth rate and maturity of the young, which can be accelerated by changing their nutritional status.

Protein composition of uterine fluids during early gestation of the tammar wallaby

Publisher: Bioscientifica

Date: 06-01-2971

DOI: 10.1530/JRF.0.0240132

Abstract: Genomic imprinting is an important epigenetic process that silences one of the parentally-inherited alleles of a gene and thereby exhibits allelic-specific expression (ASE). Detection of human imprinting events is h ered by the infeasibility of the reciprocal mating system in humans and the removal of ASE events arising from non-imprinting factors. Here, we describe a pipeline with the pattern of reciprocal allele descendants (RADs) through genotyping and transcriptome sequencing data across independent parent-offspring trios to discriminate between varied types of ASE (e.g., imprinting, genetic variation-dependent ASE, and random monoallelic expression (RME)). We show that the vast majority of ASE events are due to sequence-dependent genetic variant, which are evolutionarily conserved and may themselves play a cis-regulatory role. Particularly, 74% of non-RAD ASE events, even though they exhibit ASE biases toward the same parentally-inherited allele across different in iduals, are derived from genetic variation but not imprinting. We further show that the RME effect may affect the effectiveness of the population-based method for detecting imprinting events and our pipeline can help to distinguish between these two ASE types. Taken together, this study provides a good indicator for categorization of different types of ASE, opening up this widespread and complex mechanism for comprehensive characterization.

Puberty in the Female Tammar Wallaby1

Publisher: Oxford University Press (OUP)

Date: 05-1998

DOI: 10.1095/BIOLREPROD58.5.1117

Abstract: The growth and timing of female puberty in a seasonally breeding marsupial, the tammar wallaby, was examined in wild and captive animals. Puberty, defined as the time of first estrus and ovulation, can occur at any time of the year. Sixty percent of young wild females went through puberty in late October-November, 3 mo before the normal adult mating season in late January-February, but puberty was delayed in captive animals kept with a low ratio of males to females. During initial cycles, 19% of these captive animals were infertile as judged by failure to conceive. In the wild, puberty occurred well before the animals were fully grown (body weight 2.0+/-0.3 kg [mean+/-SD], n=23 adult females, 4.7+/-0.6 kg n=34). Only 3% of animals with a body weight below 1.5 kg had ovulated. Thus, attainment of a minimum body weight was a key prerequisite associated with puberty. Progesterone concentrations in the peripheral plasma of prepubertal females were not significantly different from those of adult females during the nonbreeding season (prepubertal, 142+/-121 pg/ml, n=34 adult, 194+/-105 pg/ml, n=32, p > 0.05). However, there was a significant increase in progesterone (322+/-242 pg/ml, n=32, p < 0.05) in the postpubertal females (ovulating but still < 3.5 kg body weight) even though the corpus luteum was quiescent after its formation. There was no increase in plasma progesterone before the first estrus. These data confirm that estrus does not require a change in the progesterone:estradiol ratio, and that a "silent" ovulation does not precede the first estrus in this species, so that the onset of puberty coincides with the first behavioral estrus and ovulation, when the animals have reached a body weight of 2 kg. Although adult female tammars are strict seasonal breeders, with 6 mo of seasonal quiescence from the winter to the summer solstice, young females can go through puberty at any time of the year. The unique feature of the female tammar wallaby is that it does not become a seasonally breeding mammal until after puberty, when it has acquired a corpus luteum.

Selected imprinting of INS in the marsupial

Publisher: Springer Science and Business Media LLC

Date: 28-08-2012

DOI: 10.1186/1756-8935-5-14

Abstract: In marsupials, growth and development of the young occur postnatally, regulated by milk that changes in composition throughout the long lactation. To initiate lactation in mammals, there is an absolute requirement for insulin ( INS ), a gene known to be imprinted in the placenta. We therefore examined whether INS is imprinted in the mammary gland of the marsupial tammar wallaby ( Macropus eugenii ) and compared its expression with that of insulin-like growth factor 2 ( IGF2 ). INS was expressed in the mammary gland and significantly increased, while IGF2 decreased, during established milk production. Insulin and IGF2 were both detected in the mammary gland macrophage cells during early lactation and in the alveolar cells later in lactation. Surprisingly, INS , which was thought only to be imprinted in the therian yolk sac, was imprinted and paternally expressed in the liver of the developing young, monoallelically expressed in the tammar mammary gland and biallelic in the stomach and intestine. The INS transcription start site used in the liver and mammary gland was differentially methylated. This is the first study to identify tissue-specific INS imprinting outside the yolk sac. These data suggest that there may be an advantage of selective monoallelic expression in the mammary gland and that this may influence the growth of the postnatal young. These results are not consistent with the parental conflict hypothesis, but instead provide support for the maternal–infant co-adaptation hypothesis. Thus, imprinting in the mammary gland maybe as critical for postnatal growth and development in mammals as genomic imprinting in the placenta is prenatally.

Towards an understanding of the genetic basis behind 1080 (sodium fluoroacetate) tolerance and an investigation of the candidate gene ACO2

Publisher: CSIRO Publishing

Date: 2013

DOI: 10.1071/ZO12108

Abstract: Sodium fluoroacetate, commonly referred to as 1080, is a pesticide heavily used to control vertebrate pests. The development of tolerance to this poison by target species is a critical concern raised by its intensive use. Tolerance to 1080 is common amongst many native vertebrates in south-west Western Australia and is thought to be the result of a long period of coevolution with plant species that produce 1080 in their seeds and flowers. Among those vertebrate species tolerant to 1080 exposure is a subspecies of the tammar wallaby (Macropus eugenii). Tammars from Western Australia are tolerant while the subspecies present on Kangaroo Island is susceptible to 1080 exposure. The availability of genetic and genomic information, combined with a distinct difference in tolerance to 1080 between subspecies, makes the tammar wallaby an ideal species in which to study the genetic basis behind 1080 resistance. To date, research in this area has focussed on a candidate gene approach. Since 1080 inhibits the action of the mitochondrial aconitase enzyme, the aconitase gene ACO2 was considered a prime candidate for involvement in 1080 tolerance. However, sequencing of the full-length ACO2 transcript failed to identify a sequence variant between the two subspecies that would result in an amino acid change in the active site of the enzyme. Future studies will need to take a genome-wide approach to identify the gene(s) responsible for 1080 tolerance.

Heterochrony in the regulation of the developing marsupial limb

Publisher: Wiley

Date: 13-11-2014

DOI: 10.1002/DVDY.24062

Abstract: At birth, marsupial neonates have precociously developed forelimbs. The development of the tammar wallaby (Macropus eugenii) hindlimbs lags significantly behind that of the forelimbs. This differs from the grey short-tailed opossum, Monodelphis domestica, which has relatively similar fore- and hindlimbs at birth. This study examines the expression of the key patterning genes TBX4, TBX5, PITX1, FGF8, and SHH in developing limb buds in the tammar wallaby. All genes examined were highly conserved with orthologues from opossum and mouse. TBX4 expression appeared earlier in development than in the mouse, but later than in the opossum. SHH expression is restricted to the zone of polarising activity, while TBX5 (forelimb) and PITX1 (hindlimb) showed diffuse mRNA expression. FGF8 is specifically localised to the apical ectodermal ridge, which is more prominent than in the opossum. The most marked ergence in limb size in marsupials occurs in the kangaroos and wallabies. The faster development of the fore limb compared to that of the hind limb correlates with the early timing of the expression of the key patterning genes in these limbs.

Successful Intra- and Interspecific Male Germ Cell Transplantation in the Rat1

Publisher: Oxford University Press (OUP)

Date: 03-2003

DOI: 10.1095/BIOLREPROD.102.009480

Abstract: The lumen of the seminiferous tubules has hitherto been regarded as an immunologically privileged site. We report here the birth of young following transplantation of stem spermatogonia from Long-Evans rats to the seminiferous tubules of Sprague-Dawley rats after treatment with the immunosuppressive agent cyclosporin. Follicle-stimulating hormone was also given to stimulate Sertoli cell proliferation, and testosterone to stimulate the recovery of spermatogenesis. Donor germ cells underwent normal spermatogenesis, and progeny were repeatedly produced from the donor germ cells as demonstrated by microsatellite paternity analysis. In addition, donor germ cells from the cryptorchid testes of LacZ mice were also able to colonize the seminiferous tubules of Sprague-Dawley rats using this protocol. Morphologically normal rat and mouse spermatozoa were present in the epididymis and vas deferens of the recipient rats. This highlights the potential for transplantation of male germ cells between different species.

Getting out of a mammalian egg: the egg tooth and caruncle of the echidna

Publisher: Elsevier BV

Date: 03-2023

DOI: 10.1016/J.YDBIO.2022.12.005

Ultrasonography of wallaby prenatal development shows that the climb to the pouch begins in utero

Publisher: Springer Science and Business Media LLC

Date: 15-03-2013

DOI: 10.1038/SREP01458

Characterisation of ATRX, DMRT1, DMRT7 and WT1 in the platypus (Ornithorhynchus anatinus)

Publisher: CSIRO Publishing

Date: 2009

DOI: 10.1071/RD09090

Abstract: One of the most puzzling aspects of monotreme reproductive biology is how they determine sex in the absence of the SRY gene that triggers testis development in most other mammals. Although monotremes share a XX female/XY male sex chromosome system with other mammals, their sex chromosomes show homology to the chicken Z chromosome, including the DMRT1 gene, which is a dosage-dependent sex determination gene in birds. In addition, monotremes feature an extraordinary multiple sex chromosome system. However, no sex determination gene has been identified as yet on any of the five X or five Y chromosomes and there is very little knowledge about the conservation and function of other known genes in the monotreme sex determination and differentiation pathway. We have analysed the expression pattern of four evolutionarily conserved genes that are important at different stages of sexual development in therian mammals. DMRT1 is a conserved sex-determination gene that is upregulated in the male developing gonad in vertebrates, while DMRT7 is a mammal-specific spermatogenesis gene. ATRX, a chromatin remodelling protein, lies on the therian X but there is a testis-expressed Y-copy in marsupials. However, in monotremes, the ATRX orthologue is autosomal. WT1 is an evolutionarily conserved gene essential for early gonadal formation in both sexes and later in testis development. We show that these four genes in the adult platypus have the same expression pattern as in other mammals, suggesting that they have a conserved role in sexual development independent of genomic location.

Author response: Molecular conservation of marsupial and eutherian placentation and lactation

Publisher: eLife Sciences Publications, Ltd

Date: 28-06-2017

DOI: 10.7554/ELIFE.27450.038

Corrigendum to: "Wolffian duct differentiation by physiological concentrations of androgen delivered systemically" [Dev. Biol. 334 (2009) 429–436, PMID:19664614]

Publisher: Elsevier BV

Date: 03-2016

DOI: 10.1016/J.YDBIO.2016.01.016

Eggs, embryos and the evolution of imprinting: insights from the platypus genome

Publisher: CSIRO Publishing

Date: 2009

DOI: 10.1071/RD09092

Abstract: Genomic imprinting is widespread in eutherian and marsupial mammals. Although there have been many hypotheses to explain why genomic imprinting evolved in mammals, few have examined how it arose. The host defence hypothesis suggests that imprinting evolved from existing mechanisms within the cell that act to silence foreign DNA elements that insert into the genome. However, the changes to the mammalian genome that accompanied the evolution of imprinting have been hard to define due to the absence of large-scale genomic resources from all extant classes. The recent release of the platypus genome sequence has provided the first opportunity to make comparisons between prototherian (monotreme, which show no signs of imprinting) and therian (marsupial and eutherian, which have imprinting) mammals. We compared the distribution of repeat elements known to attract epigenetic silencing across the genome from monotremes and therian mammals, particularly focusing on the orthologous imprinted regions. Our analyses show that the platypus has significantly fewer repeats of certain classes in the regions of the genome that have become imprinted in therian mammals. The accumulation of repeats, especially long-terminal repeats and DNA elements, in therian imprinted genes and gene clusters therefore appears to be coincident with, and may have been a potential driving force in, the development of mammalian genomic imprinting. Comparative platypus genome analyses of orthologous imprinted regions have provided strong support for the host defence hypothesis to explain the origin of imprinting.

Mesotocin receptors during pregnancy, parturition and lactation in the tammar wallaby

Publisher: Elsevier BV

Date: 04-1998

DOI: 10.1016/S0378-4320(98)00056-6

Abstract: Mestocin receptor concentrations in membrane preparations from reproductive tissues of the tammar Macropus eugenii throughout gestation and lactation were assessed using [3H]-oxytocin as the ligand. There was a single binding site which bound both mesotocin and oxytocin with high and similar affinities. Mesotocin receptor concentrations in the myometrium were low (708 +/- 199 fmol mg-1 protein) in early and middle gestation but increased significantly on day 23 of pregnancy of the 26-day gestation period to 1921 +/- 552 fmol mg-1 protein. Myometrial receptors reached a peak of 2483 +/- 575 fmol mg-1 protein on days 25 and 26 of gestation, but returned to basal levels about an hour after birth. Receptor concentrations in the contralateral non-gravid uterus were much lower (605 +/- 75 fmol mg-1) and did not significantly increase throughout the period of gestation but dropped one day before birth. Mesotocin receptors were undetectable in the endometrium, the yolk sac placenta and the lateral, median and anterior vagina of all animals tested. In the lactating mammary gland after birth mesotocin receptors were initially high (588 +/- 38 fmol mg-1) but decreased after 200 days and by late lactation were 224 +/- 55 fmol mg-1 protein on day 240, close to the time of weaning. Mesotocin receptors in the ipsilateral non-lactating gland were also high in early lactation (430 +/- 153 fmol mg-1) and declined in late lactation (62 +/- 20 fmol mg-1). The changing concentrations of mesotocin receptors in pregnancy and lactation demonstrate that they are specifically regulated in tammar reproductive tissues. The increase in mesotocin receptors in gravid, but not in the non-gravid myometrium three days before birth may make the uterus responsive to the surge of mesotocin at birth. Since this rise is unilateral and only occurs in the gravid myometrium it must be due to local effects from the ipsilateral ovary or the feto-placental unit. Likewise, the down-regulation of mesotocin receptors in the contralateral, non-gravid myometrium may be due to its proximity to the developing follicle. The changing concentrations in the lactating and the adjacent, non-lactating mammary gland also reflect a differential regulation of mesotocin receptors, probably mediated via the sucking stimulus. Thus, local influences appear to be of primary importance in the regulation of mesotocin receptors during reproduction in this marsupial.

Uterine and embryonic metabolism after diapause in the tammar wallaby, Macropus eugenii

Publisher: Bioscientifica

Date: 1986

DOI: 10.1530/JRF.0.0760339

Abstract: Pouch young were removed from lactating tammars to terminate embryonic diapause. Uterine metabolism was assessed at periods afterwards by incubating endometrial explants with [3H]leucine, and measuring the incorporation into acid-soluble material. Blastocysts were incubated with [3H]uridine to assess uptake and incorporation into acid-soluble material. Uterine reactivation, shown by an increase in the rate of leucine incorporation into secreted protein, was evident by Day 4 after removal of pouch young and was significantly more in both secreted and tissue protein by Day 6. Both continued to increase in gravid and non-gravid uteri up to Day 12. By the end of pregnancy (Day 26) uterine metabolism in the gravid uterus produced 2-3 times more secreted protein than in the non-gravid uterus, demonstrating a local feto-placental influence on the uterus. Tissue incorporation had declined in endometrium of gravid and non-gravid uteri by Day 26. Day 5 embryos were metabolically more active than in quiescence, although expansion of the embryos was not seen until Day 9. The early reactivation of the uterus and embryo from diapause suggests that it is not triggered by the previously described peaks of progesterone and oestradiol in plasma at Day 5, although there may be an earlier, increased sensitivity to these steroids which allows uterine reactivation to precede changes in peripheral plasma concentration.

Orientation pinwheels in primary visual cortex of a highly visual marsupial

Publisher: American Association for the Advancement of Science (AAAS)

Date: 30-09-2022

DOI: 10.1126/SCIADV.ABN0954

Abstract: Primary visual cortices in many mammalian species exhibit modular and periodic orientation preference maps arranged in pinwheel-like layouts. The role of inherited traits as opposed to environmental influences in determining this organization remains unclear. Here, we characterize the cortical organization of an Australian marsupial, revealing pinwheel organization resembling that of eutherian carnivores and primates but distinctly different from the simpler salt-and-pepper arrangement of eutherian rodents and rabbits. The ergence of marsupials from eutherians 160 million years ago and the later emergence of rodents and rabbits suggest that the salt-and-pepper structure is not the primitive ancestral form. Rather, the genetic code that enables complex pinwheel formation is likely widespread, perhaps extending back to the common therian ancestors of modern mammals.

Retrotransposon Silencing by DNA Methylation Can Drive Mammalian Genomic Imprinting

Publisher: Public Library of Science (PLoS)

Date: 13-04-2007

DOI: 10.1371/JOURNAL.PGEN.0030055

Characterisation of marsupial PHLDA2 reveals eutherian specific acquisition of imprinting

Publisher: Springer Science and Business Media LLC

Date: 19-08-2011

DOI: 10.1186/1471-2148-11-244

Abstract: Genomic imprinting causes parent-of-origin specific gene expression by differential epigenetic modifications between two parental genomes. We previously reported that there is no evidence of genomic imprinting of CDKN1C in the KCNQ1 domain in the placenta of an Australian marsupial, the tammar wallaby ( Macropus eugenii ) whereas tammar IGF2 and H19 , located adjacent to the KCNQ1 domain in eutherian mammals, are imprinted. We have now identified and characterised the marsupial orthologue of PHLDA2 , another gene in the KCNQ1 domain (also known as IPL or TSSC3 ) that is imprinted in eutherians. In mice, Phlda2 is a dose-sensitive negative regulator of placental growth, as Cdkn1c is for embryonic growth. Tammar PHLDA2 is highly expressed in the yolk sac placenta compared to other fetal tissues, confirming a similar expression pattern to that of mouse Phlda2 . However, tammar PHLDA2 is biallelically expressed in both the fetus and yolk sac placenta, so it is not imprinted. The lack of imprinting in tammar PHLDA2 suggests that the acquisition of genomic imprinting of the KCNQ1 domain in eutherian mammals, accompanied with gene dosage reduction, occurred after the split of the therian mammals into the marsupials and eutherians. Our results confirm the idea that acquisition of genomic imprinting in the KCNQ1 domain occurred specifically in the eutherian lineage after the ergence of marsupials, even though imprinting of the adjacent IGF2-H19 domain arose before the marsupial-eutherian split. These data are consistent with the hypothesis that genomic imprinting of the KCNQ1 domain may have contributed to the evolution of more complex placentation in the eutherian lineage by reduction of the gene dosage of negative regulators for both embryonic and placental growth.

Molecular conservation of marsupial and eutherian placentation and lactation

Publisher: eLife Sciences Publications, Ltd

Date: 12-09-2017

DOI: 10.7554/ELIFE.27450

Abstract: Eutherians are often mistakenly termed ‘placental mammals’, but marsupials also have a placenta to mediate early embryonic development. Lactation is necessary for both infant and fetal development in eutherians and marsupials, although marsupials have a far more complex milk repertoire that facilitates morphogenesis of developmentally immature young. In this study, we demonstrate that the anatomically simple tammar placenta expresses a dynamic molecular program that is reminiscent of eutherian placentation, including both fetal and maternal signals. Further, we provide evidence that genes facilitating fetal development and nutrient transport display convergent co-option by placental and mammary gland cell types to optimize offspring success.

Foetal origin of transferrin in mouse amniotic fluid

Publisher: Springer Science and Business Media LLC

Date: 11-1974

DOI: 10.1038/252159A0

Abstract: In this paper, a parametric method is introduced to solve fuzzy transportation problem. Considering that parameters of transportation problem have uncertainties, this paper develops a generalized fuzzy transportation problem with fuzzy supply, demand and cost. For simplicity, these parameters are assumed to be fuzzy trapezoidal numbers. Based on possibility theory and consistent with decision-makers' subjectiveness and practical requirements, the fuzzy transportation problem is transformed to a crisp linear transportation problem by defuzzifying fuzzy constraints and objectives with application of fractile and modality approach. Finally, a numerical ex le is provided to exemplify the application of fuzzy transportation programming and to verify the validity of the proposed methods.

Isolation and partial characterization of tammar wallaby luteinizing hormone and development of a radioimmunoassay

Publisher: CSIRO Publishing

Date: 1997

DOI: 10.1071/R96089

Abstract: Tammar wallaby (Macropus eugenii) luteinizing hormone (LH) was purified from pituitaries collected from wild and captive populations by salt sequential precipitation, ion exchange chromatography and gel filtration. Pituitary tissue (5 g) yielded 1·8 mg of purified wallaby luteinizing hormone (ME-14B), as verified by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). A heterologous radioimmunoassay has been developed for measurement of LH in plasma of marsupials using a monoclonal antibody raised against bovine LH (518B7). This assay system was able to measure basal LH concentrations in male and female tammars and detected a significant rise in plasma LH in response to oestradiol benzoate in female tammars and luteinizing hormone-releasing hormone (LHRH) in males. Parallel dose–response curves were also obtained from pituitary extracts from four other species of marsupial (brushtail possum, Trichosurus vulpecula brown antechinus,Antechinus stuartii kowari, Dasyuroides byrnei and Eastern pygmy possum,Cercartetus nanus) in this assay, which suggests its usefulness in the measurement of LH in other marsupial species.

Testosterone Control of Male-Type Sexual Behavior in the Tammar Wallaby (Macropus eugenii)

Publisher: Elsevier BV

Date: 12-1996

DOI: 10.1006/HBEH.1996.0049

Abstract: In the tammar wallaby, Macropus eugenii, the expression of male-type sexual behavior is apparently determined by the activating effects of testicular hormones in adulthood. The incidence of male-type copulatory behavior and sexual checking behavior was compared in intact (control) males, control females, testosterone-treated females, and three groups of males castrated either postnatally (24-26 days of age), prepubertally (14.5 months of age), or in adulthood. All three groups of castrated male wallabies showed a very low incidence of male sexual behavior in adult life, comparable to that shown by the untreated females. Adult female wallabies with 100-mg testosterone implants showed a high incidence of male sexual behavior which was indistinguishable from that shown by intact males. The results suggest that sex differences in male-type behavior in the tammar wallaby are due to short-term inductive effects of testosterone acting on a sexually indifferent brain. There is no evidence of any long-term organizational effects of testosterone acting in fetal or neonatal life on the neural pathways controlling male-type sex behavior in this marsupial mammal.

Sexual Development in Marsupial Pouch Young

Publisher: Springer Berlin Heidelberg

Date: 1988

DOI: 10.1007/978-3-642-88402-3_15

Reproduction in female swamp wallabies, Wallabia bicolor

Publisher: CSIRO Publishing

Date: 2006

DOI: 10.1071/RD06024

Abstract: The sw wallaby (Wallabia bicolor) is a common, medium-sized, browsing macropodid marsupial that is unique in many ways. Relatively little is known about the reproductive biology of this species. Previous studies have proposed that the sw wallaby has a pre-partum oestrus because the gestation period ( x ¯ -- x = 35.5 days, n = 4) is on average longer than the oestrus period ( x ¯ -- x = 31.0 days, n = 5) and the period from the removal of pouch young (RPY) to mating ( x ¯ -- x = 26.0days, n = 3). In the current study, the period from RPY to birth was confirmed at x ¯ -- x = 31.25 days (n = 4) in captive animals, consistent with a pre-partum oestrus. A growth curve for sw wallaby pouch young was constructed from the progeny of captive animals to estimate the age and date of birth of young in a wild, culled population in South Gippsland, Victoria, and the reproduction of females in the wild throughout the year was examined. Young were born in every month of the year, with no statistically significant variation in the number of young born in each month. Females did not have a period of seasonal anoestrus and conceived throughout the year. Female sw wallabies in South Gippsland bred continuously throughout the period of this study.

A novel MSMB-related microprotein in the postovulatory egg coats of marsupials

Publisher: Springer Science and Business Media LLC

Date: 2011

DOI: 10.1186/1471-2148-11-373

Influence of the Embryo on the Marsupial Uterus

Publisher: Springer Science and Business Media LLC

Date: 12-1972

DOI: 10.1038/240475A0

Abstract: The horizon scanning review aimed to identify new and emerging technologies in development that have the potential to slow or stop disease progression and/or reverse sight loss in people with inherited retinal diseases (IRDs). Potential treatments were identified using recognized horizon scanning methods. These included a combination of online searches using predetermined search terms, suggestions from clinical experts and patient and carer focus groups, and contact with commercial developers. Twenty-nine relevant technologies were identified. These included 9 gene therapeutic approaches, 10 medical devices, 5 pharmacological agents, and 5 regenerative and cell therapies. A further 11 technologies were identified in very early phases of development (typically phase I or pre-clinical) and were included in the final report to give a complete picture of developments 'on the horizon'. Clinical experts and patient and carer focus groups provided helpful information and insights, such as the availability of specialised services for patients, the potential impacts of in idual technologies on people with IRDs and their families, and helped to identify additional relevant technologies. This engagement ensured that important areas of innovation were not missed. Most of the health technologies identified are still at an early stage of development and it is difficult to estimate when treatments might be available. Further, well designed trials that generate data on efficacy, applicability, acceptability, and costs of the technologies, as well as the long-term impacts for various conditions are required before these can be considered for adoption into routine clinical practice.

Inducing Sex Reversal in Marsupial Mammals

Publisher: S. Karger AG

Date: 2016

DOI: 10.1159/000450927

Abstract: Marsupials are born with undifferentiated gonads, and their reproductive organs differentiate consecutively, not simultaneously as in eutherian mammals. Thus, in the main marsupial model, the tammar wallaby, i Macropus eugenii, /i the testis forms cords 2 days after birth, the ovary develops cortex and medulla about 8 days after birth, the Wolffian duct enlarges from day 10, the prostate begins to form prostatic buds about 25 days after birth, and the phallus does not become sexually dimorphic until after 50 days postpartum (pp). The brain responses also become sexually dimorphic relatively late in development, after day 25 pp. This relatively elongated period of differentiation has allowed experimental manipulation at each stage of development to induce often dramatic sex reversal of both internal and external genitalia.

Use of genetic methods to establish male-biased dispersal in a cryptic mammal, the swamp wallaby (Wallabia bicolor)

Publisher: CSIRO Publishing

Date: 2009

DOI: 10.1071/ZO09014

Abstract: Mammalian dispersal tends to be male-biased although female-biased dispersal has also been reported in a range of taxa. Most of our knowledge on mammalian sex-biased dispersal is based on studies of eutherians and less work has been done on the direction and causes of sex-biased dispersal in marsupials. This study investigated dispersal of sw wallabies between two habitat patches in South Gippsland, Victoria, using genetic methods. A Bayesian clustering test showed a high level of genetic exchange between the two habitat patches despite their separation by 10–17 km of cleared land, a creek and a highway. Females in the overall s le were more closely related to each other than males were to each other and females within habitat patches were more closely related than females between habitat patches whereas the converse was true for males. Bayesian inference showed that more males were migrating from the east to the west habitat patch whereas the converse was true for females and the male migration rate was higher than the female migration rate. The differential migration rate did not cause a significant difference in relatedness between patches in females but it did in males. These relatedness and migration patterns indicate that dispersal in the sw wallaby is male-biased.

Placental Function in Two Distantly Related Marsupials

Publisher: Elsevier BV

Date: 02-2007

DOI: 10.1016/J.PLACENTA.2006.03.007

Abstract: The biochemical composition of uterine and fetal fluids during pregnancy of the grey short-tailed opossum was compared with new and published data on the tammar wallaby. In the grey short-tailed opossum, there are three main phases of embryonic nourishment. During the first phase, the embryo obtains nutrients from uterine secretion transferred into the yolk sac. The amount of uterine secretion declines during the second phase up to the time of shell coat rupture. As a result, the protein concentration in yolk sac fluid also declines. During phase three, which begins with shell coat rupture, nutrients are predominantly available from the maternal blood. In the grey short-tailed opossum that lacks a vesicular, fluid-filled allantois, waste products such as urea are apparently stored in the yolk sac and from there pass into the maternal circulation across the invasive yolk sac placenta. In contrast, in the tammar wallaby, the main source of nutrients available to the late term fetus is glandular secretion that is complemented by substances from the maternal circulation via the chorio-vitelline placenta, and waste products are stored in the large, fluid-filled allantois.

The alternate pathway of androgen metabolism and window of sensitivity

Publisher: Bioscientifica

Date: 21-06-2023

DOI: 10.1530/JOE-22-0296

Abstract: Since the discovery in 1968 that dihydrotestosterone (DHT) is a major mediator of androgen action, a convincing body of evidence has accumulated to indicate that the major pathway of DHT formation is the 5α-reduction of circulating testosterone in androgen target tissues. However, we now know that DHT can also be formed in peripheral tissues by the oxidation of 5α-androstane-3α,17β-diol (adiol). This pathway is responsible for the formation of the male phenotype. We discuss the serendipitous discovery in the tammar wallaby of an alternate pathway by which adiol is formed in the testes, secreted into plasma and converted in peripheral tissues to DHT. This alternate pathway is responsible for virilisation of the urogenital system in this species and is present in the testes at the onset of male puberty of all mammals studied so far. This is the first clear-cut function for steroid 5α-reductase 1 in males. Unexpectedly, the discovery of this pathway in this Australian marsupial has had a major impact in understanding the pathophysiology of aberrant virilisation in female newborns. Overactivity of the alternate pathway appears to explain virilisation in congenital adrenal hyperplasia CAH, in X-linked 46,XY disorders of sex development. It also appears to be important in polycystic ovarian syndrome (PCOS) since PCOS ovaries have enhanced the expression of genes and proteins of the alternate pathway. It is now clear that normal male development in marsupials, rodents and humans requires the action of both the classic and the alternate (backdoor) pathways.

Design and experimental testing of air slab caps which convert commercial electron diodes into dual purpose, correction‐free diodes for small field dosimetry

Publisher: Wiley

Date: 10-2014

DOI: 10.1118/1.4894728

Abstract: Two diodes which do not require correction factors for small field relative output measurements are designed and validated using experimental methodology. This was achieved by adding an air layer above the active volume of the diode detectors, which canceled out the increase in response of the diodes in small fields relative to standard field sizes. Due to the increased density of silicon and other components within a diode, additional electrons are created. In very small fields, a very small air gap acts as an effective filter of electrons with a high angle of incidence. The aim was to design a diode that balanced these perturbations to give a response similar to a water-only geometry. Three thicknesses of air were placed at the proximal end of a PTW 60017 electron diode (PTWe) using an adjustable "air cap". A set of output ratios (ORDet (fclin) ) for square field sizes of side length down to 5 mm was measured using each air thickness and compared to ORDet (fclin) measured using an IBA stereotactic field diode (SFD). kQclin,Qmsr (fclin,fmsr) was transferred from the SFD to the PTWe diode and plotted as a function of air gap thickness for each field size. This enabled the optimal air gap thickness to be obtained by observing which thickness of air was required such that kQclin,Qmsr (fclin,fmsr) was equal to 1.00 at all field sizes. A similar procedure was used to find the optimal air thickness required to make a modified Sun Nuclear EDGE detector (EDGEe) which is "correction-free" in small field relative dosimetry. In addition, the feasibility of experimentally transferring kQclin,Qmsr (fclin,fmsr) values from the SFD to unknown diodes was tested by comparing the experimentally transferred kQclin,Qmsr (fclin,fmsr) values for unmodified PTWe and EDGEe diodes to Monte Carlo simulated values. 1.0 mm of air was required to make the PTWe diode correction-free. This modified diode (PTWeair) produced output factors equivalent to those in water at all field sizes (5-50 mm). The optimal air thickness required for the EDGEe diode was found to be 0.6 mm. The modified diode (EDGEeair) produced output factors equivalent to those in water, except at field sizes of 8 and 10 mm where it measured approximately 2% greater than the relative dose to water. The experimentally calculated kQclin,Qmsr (fclin,fmsr) for both the PTWe and the EDGEe diodes (without air) matched Monte Carlo simulated results, thus proving that it is feasible to transfer kQclin,Qmsr (fclin,fmsr) from one commercially available detector to another using experimental methods and the recommended experimental setup. It is possible to create a diode which does not require corrections for small field output factor measurements. This has been performed and verified experimentally. The ability of a detector to be "correction-free" depends strongly on its design and composition. A nonwater-equivalent detector can only be "correction-free" if competing perturbations of the beam cancel out at all field sizes. This should not be confused with true water equivalency of a detector.

Post-natal imprinting: evidence from marsupials

Publisher: Springer Science and Business Media LLC

Date: 05-03-2014

DOI: 10.1038/HDY.2014.10

Carbohydrate uptake by quiescent and reactivated mouse blastocysts

Publisher: Wiley

Date: 10-1996

DOI: 10.1002/(SICI)1097-010X(19961001)276:2<132::AID-JEZ6>3.0.CO;2-P

Abstract: Defects in the human solute carrier family 26 member 4 ( Patients with primary CH were screened for 21 CH candidate genes mutations by targeted next-generation sequencing. All the exons and exon-intron boundaries of Among 273 patients with CH, seven distinct The prevalence of

A Comparison of Seasonal Changes in the Pollen Loads of Nectarivorous Marsupials [Tarsipes] and Birds [Honeyeaters].

Publisher: CSIRO Publishing

Date: 1983

DOI: 10.1071/WR9830311

Abstract: Pollen loads on nectar-feeding marsupials (Tarsipes) and honeyeater birds were monitored for a year at a site on the south coast of Western Australia. Birds carried more pollen grains than the mammals. Both groups carried the same pollens of the main nectar-producing plants in the area and their pollen loads followed the patterns of flowering. Those Banksia species whose pollen was carried most by vertebrates set most seed.

Prostaglandin D₂ Regulates SOX9 Nuclear Translocation during Gonadal Sex Determination in Tammar Wallaby, Macropus eugenii

Publisher: S. Karger AG

Date: 2017

DOI: 10.1159/000473782

Abstract: Sex determination and sexual differentiation pathways are highly conserved between marsupials and eutherians. There are 2 different pathways of prostaglandin D sub /sub (PGD sub /sub ) synthesis: prostaglandin D synthase (PTGDS) and haematopoietic prostaglandin D synthase (HPGDS). PGD sub /sub regulates the subcellular localization of SOX9 during gonadal sexual differentiation. To investigate the function of PGD sub /sub in the tammar gonad, we cultured undifferentiated male gonads in the presence of the HPGDS inhibitor HQL-79 and female gonads with exogenous PGD sub /sub to mimic activation of the PTGDS-PGD sub /sub pathway. Tammar PTGDS and HPGDS have only 50% similarity with mouse and human orthologues, but functional domains are conserved. The expression of i SOX9 /i was unchanged by the treatments in cultured gonads, but its subcellular localization was markedly affected. SOX9 remained cytoplasmic in the Sertoli cells of testes treated with HQL-79. Treated testes developed a thickened ovary-like surface epithelium. In contrast, SOX9 became nuclear in the granulosa cells of developing ovaries treated with PGD sub /sub and the surface epithelium was thin, as in testes. These results demonstrate that PGD sub /sub regulates the subcellular localization of SOX9 and subsequent gonadal development in the developing marsupial gonads, as it does in mice, and that it must have been an ancestral mechanism.

A Technique for Sampling Pollen Carried by Vertebrates.

Publisher: CSIRO Publishing

Date: 1983

DOI: 10.1071/WR9830433

Mesotocin and luteal function in macropodid marsupials

Publisher: Bioscientifica

Date: 06-1988

DOI: 10.1677/JOE.0.1170367

Abstract: Pituitary glands and corpora lutea collected at various stages of the reproductive cycle of the tammar wallaby ( Macropus eugenii ), were extracted and fractionated by high-performance liquid chromatography, and specific radioimmunoassays were used to measure mesotocin ([Ile 8 ]-oxytocin) and oxytocin. Mesotocin, but not oxytocin, was identified in extracts of pituitary the mean concentration of mesotocin in this tissue was 0·75 nmol/g wet weight. Neither mesotocin nor oxytocin was detected in extracts of corpus luteum. In female Bennett's wallabies passively immunized against mesotocin during seasonal reproductive quiescence, there was no significant effect on peripheral progesterone concentrations and there were no births, matings or changes in vaginal smears in the 2 months following treatment. Thus mesotocin is unlikely to act as a systemic luteostatic agent during seasonal quiescence. J. Endocr. (1988) 117, 367–372

Correction to: Genetic sex test for the short-beaked echidna (Tachyglossus aculeatus)

Publisher: Springer Science and Business Media LLC

Date: 28-05-2022

DOI: 10.1007/S12686-022-01277-0

Long-term efficacy of levonorgestrel implants for fertility control of eastern grey kangaroos (Macropus giganteus)

Publisher: CSIRO Publishing

Date: 2008

DOI: 10.1071/WR07133

Abstract: Overabundant populations of kangaroos pose substantial management problems in small parks on the fringe of urban areas in Australia. Translocation is impractical and culling is often not publicly acceptable, but fertility control offers an acceptable alternative. One potential contraceptive is levonorgestrel, which provides effective long-term contraception in women, and prevents births in some marsupials for up to five years. We evaluated the long-term efficacy of levonorgestrel in free-ranging eastern grey kangaroos (M. giganteus) at two sites in Victoria, Australia. We trapped 25 adult females at one site (Portland Aluminium), treating 18 with two subcutaneous 70-mg levonorgestrel implants and seven with control (inert) implants. We darted 25 adult females at the other site (Woodlands Historic Park), treating all with two 70-mg levonorgestrel implants. We monitored the reproductive status of the kangaroos, as indicated by the obvious presence of a pouch young, in spring each year for up to seven years. In the first three years at Portland, 81–86% of levonorgestrel-treated females were infertile, compared with 12–29% in the control group, but the effectiveness of fertility control declined over time. At this site, the proportions of treated females breeding in the fourth, fifth, sixth and seventh years of the trial were 36%, 50%, 67% and 100% respectively. Fecundity at Woodlands was similar. Although this protocol achieved fertility control for several years, it was likely that more than one treatment or a higher dose rate would be required for effective fertility control in this long-lived species.

GRB10 Imprinting Is Eutherian Mammal Specific

Publisher: Oxford University Press (OUP)

Date: 10-07-2012

DOI: 10.1093/MOLBEV/MSS173

Abstract: GRB10 is an imprinted gene differently expressed from two promoters in mouse and human. Mouse Grb10 is maternally expressed from the major promoter in most tissues and paternally expressed from the brain-specific promoter within specific regions of the fetal and adult central nervous system. Human GRB10 is biallelically expressed from the major promoter in most tissues except in the placental villus trophoblast where it is maternally expressed, whereas the brain-specific promoter is paternally expressed in the fetal brain. This study characterized the ortholog of GRB10 in a marsupial, the tammar wallaby (Macropus eugenii) to investigate the origin and evolution of imprinting at this locus. The protein coding exons and predicted amino acid sequence of tammar GRB10 were highly conserved with eutherian GRB10. The putative first exon, which is located in the orthologous region to the eutherian major promoter, was found in the tammar, but no exon was found in the downstream region corresponding to the eutherian brain-specific promoter, suggesting that marsupials only have a single promoter. Tammar GRB10 was widely expressed in various tissues including the brain but was not imprinted in any of the tissues examined. Thus, it is likely that GRB10 imprinting evolved in eutherians after the eutherian-marsupial ergence approximately 160 million years ago, subsequent to the acquisition of a brain-specific promoter, which resides within the imprinting control region in eutherians.

Concentrations of oestradiol-17  in plasma and corpora lutea throughout pregnancy in the tammar, Macropus eugenii

Publisher: Bioscientifica

Date: 09-1984

DOI: 10.1530/JRF.0.0720029

Abstract: Oestradiol-17 beta concentrations were measured by radioimmunoassay in peripheral blood s les from 10 tammar wallabies after their pouch young were removed to terminate embryonic diapause. Oestradiol concentrations rose from 8.3 +/- 1.2 pg/ml on Days 3 and 4 to peak of 15.8 +/- 2.9 pg/ml on Day 5, coincident with an increase in 'progesterone' concentrations, and then fell to 10.5 +/- 2.7 pg/ml on Day 7. No changes in oestradiol concentrations were associated with parturition. Five females came into oestrus and mated 9.8 +/- 6.1 h post partum peak concentrations of plasma oestradiol (20.9 +/- 2.1 pg/ml) occurred around the time of mating. None of the females that did not mate up to the end of the experiment at Day 30 had a rise in plasma oestradiol concentrations. Corpora lutea contained 20-100 pg oestradiol during pregnancy. The highest ovarian oestradiol content (greater than 1200 pg) was measured in whole ovaries containing Graafian follicles from full-term pregnant females. The rise in oestradiol concentrations at Day 5 may be important in the termination of diapause. The post-partum increase in plasma oestradiol concentrations coincides with oestrus. The source of this oestrogen appears to be the preovulatory follicle.

Sexual differentiation in three unconventional mammals: Spotted hyenas, elephants and tammar wallabies

Publisher: Elsevier BV

Date: 11-2005

DOI: 10.1016/J.YHBEH.2005.07.013

Abstract: The present review explores sexual differentiation in three non-conventional species: the spotted hyena, the elephant and the tammar wallaby, selected because of the natural challenges they present for contemporary understanding of sexual differentiation. According to the prevailing view of mammalian sexual differentiation, originally proposed by Alfred Jost, secretion of androgen and anti-Mullerian hormone (AMH) by the fetal testes during critical stages of development accounts for the full range of sexually dimorphic urogenital traits observed at birth. Jost's concept was subsequently expanded to encompass sexual differentiation of the brain and behavior. Although the central focus of this review involves urogenital development, we assume that the novel mechanisms described in this article have potentially significant implications for sexual differentiation of brain and behavior, a transposition with precedent in the history of this field. Contrary to the "specific" requirements of Jost's formulation, female spotted hyenas and elephants initially develop male-type external genitalia prior to gonadal differentiation. In addition, the administration of anti-androgens to pregnant female spotted hyenas does not prevent the formation of a scrotum, pseudoscrotum, penis or penile clitoris in the offspring of treated females, although it is not yet clear whether the creation of masculine genitalia involves other steroids or whether there is a genetic mechanism bypassing a hormonal mediator. Wallabies, where sexual differentiation occurs in the pouch after birth, provide the most conclusive evidence for direct genetic control of sexual dimorphism, with the scrotum developing only in males and the pouch and mammary glands only in females, before differentiation of the gonads. The development of the pouch and mammary gland in females and the scrotum in males is controlled by genes on the X chromosome. In keeping with the "expanded" version of Jost's formulation, secretion of androgens by the fetal testes provides the best current account of a broad array of sex differences in reproductive morphology and endocrinology of the spotted hyena, and androgens are essential for development of the prostate and penis of the wallaby. But the essential circulating androgen in the male wallaby is 5alpha androstanediol, locally converted in target tissues to DHT, while in the pregnant female hyena, androstenedione, secreted by the maternal ovary, is converted by the placenta to testosterone (and estradiol) and transferred to the developing fetus. Testicular testosterone certainly seems to be responsible for the behavioral phenomenon of musth in male elephants. Both spotted hyenas and elephants display matrilineal social organization, and, in both species, female genital morphology requires feminine cooperation for successful copulation. We conclude that not all aspects of sexual differentiation have been delegated to testicular hormones in these mammals. In addition, we suggest that research on urogenital development in these non-traditional species directs attention to processes that may well be operating during the sexual differentiation of morphology and behavior in more common laboratory mammals, albeit in less dramatic fashion.

The marsupial placenta: A phylogenetic analysis

Publisher: Wiley

Date: 25-08-2003

DOI: 10.1002/JEZ.A.10291

Abstract: The structure, physiology, and endocrinology of the yolk sac placenta of different marsupial groups is compared and phylogenetically analyzed to provide information on placental characters in the marsupial stem species. We conclude that the marsupial stem species possessed a functional yolk sac placenta. Histotrophic nutrition by uterine secretion decreased during late pregnancy and at least half of the yolk sac was vascularized at the time of shell coat rupture. Due to yolk sac fusion, the larger part of the avascular, bilaminar yolk sac could not serve as a placenta at late gestation in the polyovular marsupial stem species. The bilaminar yolk sac gained a relatively greater importance for nutrition in monovular australidelphians. In macropodids a greater proportion of the yolk sac remained bilaminar at the time of shell coat rupture than in the stem species. Another derived feature of macropodids is the sustained plasma progesterone synthesis that is in turn responsible for an extended secretory phase of the uterus and a lengthened gestation. The placenta of the marsupial stem species was probably capable of metabolising histo- and hemotrophes. Recognition of pregnancy during early stages of development is a derived character of macropodids that we suggest did not occur in the marsupial stem species. However, birth and birth behaviour were apparently induced by prostaglandins in the marsupial stem species. Although the yolk sac formed the definitive placenta, it is likely that the allantois provided a supplementary placental function in the marsupial stem species, but that the role of the allantois became progressively less important during the evolution of marsupial placentation.

Mullerian duct regression in a marsupial, the tammar wallaby

Publisher: Springer Science and Business Media LLC

Date: 26-06-1997

DOI: 10.1007/S004290050078

Abstract: Müllerian duct regression is first apparent in male pouch young of the tammar wallaby (Macropus eugenii) 6-7 days after birth and, as in eutherian mammals, is characterised by a condensation of the periductal mesenchyme into a whorl around the ductal epithelial cells. A decrease in the density of the extracellular matrix was observed in the region of the whorl. In contrast to eutherian mammals no changes were observed in the mean outer diameter of the Müllerian duct during the early stages of regression. The time at which these mesenchymal changes occur corresponds to the period of Müllerian inhibiting substance secretion in the postnatal tammar testis.

Ultrasound-triggered release from metal shell microcapsules

Publisher: Elsevier BV

Date: 10-2019

DOI: 10.1016/J.JCIS.2019.07.020

Abstract: Metal shell microcapsules have been shown to completely retain their core until its release is triggered, making them a promising candidate for use as a controllable drug delivery vehicle due to their superior retention properties as compared to polymer shell microcapsules. Focused ultrasound (FUS) has been successfully utilised to trigger release of lipophilic drugs from polymer microcapsules, and in this work the response of gold shell microcapsules with and without an inner polymeric shell, to FUS and standard ultrasound is explored. The results show that gold shell microcapsules with an inner polymer shell rupture when exposed to standard ultrasound and that there is a linear correlation between the gold shell thickness and the extent of shell rupture. When FUS is applied to these microcapsules, powers as low as 0.16 W delivered in bursts of 10 ms/s over a period of 120 s are sufficient to cause rupture of 53 nm gold shell microcapsules. Additional findings suggest that gold shell microcapsules without the polymer layer dispersed in a hydrogel matrix, as opposed to aqueous media, rupture more efficiently when exposed to FUS, and that thicker gold shells are more responsive to ultrasound-triggered rupture regardless of the external environment. Release of dye from all successfully ruptured capsules was sustained over a period of between 7 and 35 days. These findings suggest that emulsion-templated gold shell microcapsules embedded in a hydrogel matrix would be suitable for use as an implantable drug delivery vehicle with FUS used to externally trigger release.

Widespread expression of the testis–determining gene SRY in a marsupial

Publisher: Springer Science and Business Media LLC

Date: 11-1995

DOI: 10.1038/NG1195-347

Abstract: There is compelling evidence from mutation analysis and transgenesis that the SRY gene isolated from human and mouse encodes the testis-determining factor on the mammalian Y chromosome. However, how SRY achieves this function is unclear. Although marsupials have been separated from eutherian mammals for approximately 100 million years, homologues of SRY have been localised to the Y chromosome of two unrelated marsupial species, the tammar wallaby and the Darling Downs dunnart. Gonadal development is fundamentally similar in eutherian and marsupial mammals, but the timing of morphological events is different. Fetal Sry transcripts are confined to somatic cells of the male mouse genital ridge between 10.5-12.5 days post coitum, corresponding with the onset of testis differentiation. Analysis of Sry gene expression in the genital ridge of normal and germ cell-deficient fetal mice has established that this gene acts in the somatic cell lineage, and is presumed to induce the formation of Sertoli cells. This assumption can be tested more critically in the tammar, where the equivalent stages of testis differentiation are observed over a 7-day period. We have examined the relationship of SRY expression to testis differentiation in the tammar wallaby. We show the marsupial SRY gene cannot be exclusively coupled to Sertoli cell differentiation, as this gene is expressed in the male fetus from several days before genital ridge formation until 40 days after birth. SRY transcripts are also present in a variety of extra-gonadal tissues in the developing young and adult male, a pattern of SRY expression similar to that observed in humans. These data indicate that, in addition to a role in testis determination, SRY may have other functions [corrected].

Oestradiol-17β in the blood during seasonal reactivation of the diapausing blastocyst in a wild population of tammar wallabies

Publisher: Bioscientifica

Date: 12-1982

DOI: 10.1677/JOE.0.0950293

Abstract: Oestradiol-17β was measured by radioimmunoassay in cardiac blood from 143 pregnant and post-partum tammar wallabies shot in the wild during reactivation of the diapausing blastocyst, embryonic development, birth and post-partum oestrus. A transient rise in circulating oestradiol on 3 January coincided with or shortly preceded corpus luteum growth and blastocyst expansion before 5 January mean corpus luteum weight was 14·3± 0·44 mg ( n = 65), while thereafter it exceeded 20 mg in two-thirds of the animals. Expanded blastocysts were first noted on 5 January. A second rise in the concentration of oestradiol in plasma, which occurred in late January, preceded parturition and coincided with follicular maturation the mean (± s.e.m. ) oestradiol concentration before 17 January was 27·9 ±1·10 pmol/l ( n = 110), whereas on or after this date it was 57·3 ± 4·15 pmol/l ( n = 33). Thus oestradiol levels in peripheral plasma increased at parturition and post-partum oestrus, and showed a rise early in gestation which may be related to the termination of diapause.

Soft-tissue thickness compensation for ultrasound transit time spectroscopy estimated bone volume fraction—an experimental replication study

Publisher: IOP Publishing

Date: 07-07-2017

DOI: 10.1088/2057-1976/AA7B47

Trophoblast specialisations during pregnancy in the tammar wallaby, Macropus eugenii: A morphological and lectin histochemical study

Publisher: Elsevier BV

Date: 07-2014

DOI: 10.1016/J.PLACENTA.2014.03.018

Abstract: The tammar wallaby has a short gestation (26.5 days) and vascular modifications to expedite transport during that brief pregnancy. Here we examine trophoblast structural attributes that would facilitate materno-fetal exchange. Four specimens of Macropus eugenii between days 23 and 26 gestation were examined using electron microscopy and 24 lectins to characterise glycosylated secretions and their internalisation. Two trophoblast phenotypes were found, flattened cells generally in contact with the underlying uterine epithelium and giant cells associated with histiotrophe. The latter appeared to penetrate uterine clefts, occasionally detach and become necrotic. Lectin histochemistry and ultrastructure indicated the presence of many lysosomes and residual bodies especially in trophoblast giant cells these contained glycans, mainly apically, which were also detected in secretions and cell debris. Trophoblast basal membranes bore extensive filopodia. Giant cells were less common in vascular trilaminar areas and here the trophoblast barrier became thinner near term. Loss of Maackia amurensis agglutinin binding suggested cleavage of terminal sialic acid residues as an early post-internalisation event in the trophoblast. Lectin staining indicated degradation occurred in an apical-basal direction, and the heavily glycosylated basal membrane appeared specialised for transport out of the cell. Granules seen ultrastructurally and histochemically, particularly in giant trophoblast cells of the bilaminar area, suggest that internalised histiotrophe is broken down here and nutrients transferred to the embryo via the specialised basal plasma membrane. The trilaminar vascular area contained mostly flattened trophoblast cells, supporting the suggestion that gaseous exchange is its primary function.

Reproduction of a marsupial: From uterus to pouch

Publisher: Elsevier BV

Date: 04-1996

DOI: 10.1016/0378-4320(96)01539-4

Androgen and Oestrogen Affect the Expression of Long Non-Coding RNAs During Phallus Development in a Marsupial

Publisher: MDPI AG

Date: 30-12-2018

DOI: 10.3390/NCRNA5010003

Abstract: There is increasing evidence that long non-coding RNAs (lncRNAs) are important for normal reproductive development, yet very few lncRNAs have been identified in phalluses so far. Unlike eutherians, phallus development in the marsupial tammar wallaby occurs post-natally, enabling manipulation not possible in eutherians in which differentiation occurs in utero. We treated with sex steroids to determine the effects of androgen and oestrogen on lncRNA expression during phallus development. Hormonal manipulations altered the coding and non-coding gene expression profile of phalluses. We identified several predicted co-regulatory lncRNAs that appear to be co-expressed with the hormone-responsive candidate genes regulating urethral closure and phallus growth, namely IGF1, AR and ESR1. Interestingly, more than 50% of AR-associated coding genes and lncRNAs were also associated with ESR1. In addition, we identified and validated three novel co-regulatory and hormone-responsive lncRNAs: lnc-BMP5, lnc-ZBTB16 and lncRSPO4. Lnc-BMP5 was detected in the urethral epithelium of male phalluses and was downregulated by oestrogen in males. Lnc-ZBTB16 was downregulated by oestrogen treatment in male phalluses at day 50 post-partum (pp). LncRSPO4 was downregulated by adiol treatment in female phalluses but increased in male phalluses after castration. Thus, the expression pattern and hormone responsiveness of these lncRNAs suggests a physiological role in the development of the phallus.

Placental imprinting of SLC22A3 in the IGF2R imprinted domain is conserved in therian mammals

Publisher: Springer Science and Business Media LLC

Date: 27-08-2022

DOI: 10.1186/S13072-022-00465-4

Abstract: The eutherian IGF2R imprinted domain is regulated by an antisense long non-coding RNA, Airn , which is expressed from a differentially methylated region (DMR) in mice. Airn silences two neighbouring genes, Solute carrier family 22 member 2 ( Slc22a2) and Slc22a3 , to establish the Igf2r imprinted domain in the mouse placenta. Marsupials also have an antisense non-coding RNA, ALID , expressed from a DMR, although the exact function of ALID is currently unknown. The eutherian IGF2R DMR is located in intron 2, while the marsupial IGF2R DMR is located in intron 12, but it is not yet known whether the adjacent genes SLC22A2 and/or SLC22A3 are also imprinted in the marsupial lineage. In this study, the imprinting status of marsupial SLC22A2 and SLC22A3 in the IGF2R imprinted domain in the chorio-vitelline placenta was examined in a marsupial, the tammar wallaby. In the tammar placenta, SLC22A3 but not SLC22A2 was imprinted. Tammar SLC22A3 imprinting was evident in placental tissues but not in the other tissues examined in this study. A putative promoter of SLC22A3 lacked DNA methylation, suggesting that this gene is not directly silenced by a DMR on its promoter as seen in the mouse. Based on immunofluorescence, we confirmed that the tammar SLC22A3 is localised in the endodermal cell layer of the tammar placenta where nutrient trafficking occurs. Since SLC22A3 is imprinted in the tammar placenta, we conclude that this placental imprinting of SLC22A3 has been positively selected after the marsupial and eutherian split because of the differences in the DMR location. Since SLC22A3 is known to act as a transporter molecule for nutrient transfer in the eutherian placenta, we suggest it was strongly selected to control the balance between supply and demand of nutrients in marsupial as it does in eutherian placentas.

Differential expression of WNT4 in testicular and ovarian development in a marsupial

Publisher: Springer Science and Business Media LLC

Date: 03-10-2006

DOI: 10.1186/1471-213X-6-44

Abstract: WNT4 is a key regulator of gonadal differentiation in humans and mice, playing a pivotal role in early embryogenesis. Using a marsupial, the tammar wallaby, in which most gonadal differentiation occurs after birth whilst the young is in the pouch, we show by quantitative PCR during early testicular and ovarian development that WNT4 is differentially expressed ingonads. Before birth, WNT4 mRNA expression was similar in indifferent gonads of both sexes. After birth, in females WNT4 mRNA dramatically increased during ovarian differentiation, reaching a peak by day 9–13 post partum (pp) when the ovarian cortex and medulla are first distinguishable. WNT4 protein was localised in the ovarian cortex and at the medullary boundary. WNT4 mRNA then steadily decreased to day 49, by which time all the female germ cells have entered meiotic arrest. In males, WNT4 mRNA was down-regulated in testes immediately after birth, coincident with the time that seminiferous cords normally form, and rose gradually after day 8. By day 49, when testicular androgen production normally declines, WNT4 protein was restricted to the Leydig cells. This is the first localisation of WNT4 protein in developing gonads and is consistent with a role for WNT4 in steroidogenesis. Our data provide strong support for the suggestion that WNT4 not only functions as an anti-testis gene during early development, but is also necessary for later ovarian and testicular function.

Reproductive and Developmental Manipulation of the Marsupial, the Tammar Wallaby Macropus eugenii

Publisher: Humana Press

Date: 2011

DOI: 10.1007/978-1-61779-210-6_18

Abstract: The developing marsupial is an ideal animal for use in biomedical research. Marsupials are mammals that have been separated from eutherian mammals for over 130-140 million years. They all deliver altricial young that complete their growth and development after birth usually in a pouch, but not all marsupials have a pouch. Their lactation changes dynamically throughout the period of pouch life, and the mother controls their growth via the production of milk that is tailor-made for each stage of development. The tammar wallaby, Macropus eugenii, has been the experimental marsupial of choice for over five decades, as it is highly amendable to handling and breeds well in captivity. The tammar is especially interesting because it has both a lactational and a seasonal control of its reproduction and embryonic diapause that normally lasts 11 months. Standard molecular techniques can be used for most manipulations in marsupials. However, there are several special techniques for treating the young for experimental surgery and for organ culture that we detail below.

SOX9 has both conserved and novel roles in marsupial sexual differentiation

Publisher: Wiley

Date: 07-2002

DOI: 10.1002/GENE.10096

Abstract: In addition to an essential role in chondrogenesis, SOX9 is a highly conserved and integral part of the testis determining pathway in human and mouse. To determine whether SOX9 is involved in sex determination in noneutherian mammals we cloned a marsupial orthologue and studied its expression. The tammar wallaby SOX9 gene proved to be highly conserved, and maps to a region of the tammar genome syntenic to human chromosome 17. Marsupial SOX9 transcripts were detected by RT-PCR in the developing limb buds and both the developing ovary and testis from the first sign of gonadal development through to adulthood. Northern blot, in situ hybridisation, and immunohistochemical analyses showed that SOX9 reaches high levels of expression in the developing testis, where it is confined to the Sertoli cell nuclei, and the brain. This is similar to the expression pattern seen in human and mouse embryos and is consistent with a conserved role for SOX9 in vertebrate brain, skeletal, and gonadal development. In addition, SOX9 was expressed in the developing scrotum and mammary gland primordium regions of the tammar up to the time of birth. SOX9 protein was also detected in the developing Wolffian duct epithelium in the male mesonephros. These previously undescribed locations of SOX9 expression suggest that SOX9 may play additional roles in the differentiation of the marsupial reproductive system.

The vomeronasal organ of the tammar wallaby

Publisher: Wiley

Date: 22-07-2008

DOI: 10.1111/J.1469-7580.2008.00933.X

The mammalian blastocyst.

Publisher: Wiley

Date: 21-01-2016

DOI: 10.1002/WDEV.220

Abstract: The blastocyst is a mammalian invention that carries the embryo from cleavage to gastrulation. For such a simple structure, it exhibits remarkable ersity in its mode of formation, morphology, longevity, and intimacy with the uterine endometrium. This review explores this ersity in the light of the evolution of viviparity, comparing the three main groups of mammals: monotremes, marsupials, and eutherians. The principal drivers in blastocyst evolution were loss of yolk coupled with evolution of the placenta. An important outcome of blastocyst development is differentiation of two extraembryonic lineages (trophoblast and hypoblast) that contribute to the placenta. While in many species trophoblast segregation is often coupled with blastocyst formation, in marsupials and at least some Afrotherians, these events do not coincide. Thus, many questions regarding the conservation of molecular mechanisms controlling these events are of great interest but currently unresolved. WIREs Dev Biol 2016, 5:210–232. doi: 10.1002/wdev.220 This article is categorized under: Early Embryonic Development Fertilization to Gastrulation Comparative Development and Evolution Model Systems Comparative Development and Evolution Evolutionary Novelties

Examination of the properties of IMRT and VMAT beams and evaluation against pre-treatment quality assurance results

Publisher: IOP Publishing

Date: 12-03-2015

DOI: 10.1088/0031-9155/60/6/2587

Abstract: This study aimed to provide a detailed evaluation and comparison of a range of modulated beam evaluation metrics, in terms of their correlation with QA testing results and their variation between treatment sites, for a large number of treatments. Ten metrics including the modulation index (MI), fluence map complexity, modulation complexity score (MCS), mean aperture displacement (MAD) and small aperture score (SAS) were evaluated for 546 beams from 122 intensity modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT) treatment plans targeting the anus, rectum, endometrium, brain, head and neck and prostate. The calculated sets of metrics were evaluated in terms of their relationships to each other and their correlation with the results of electronic portal imaging based quality assurance (QA) evaluations of the treatment beams. Evaluation of the MI, MAD and SAS suggested that beams used in treatments of the anus, rectum, head and neck were more complex than the prostate and brain treatment beams. Seven of the ten beam complexity metrics were found to be strongly correlated with the results from QA testing of the IMRT beams (p < 0.00008). For ex le, values of SAS (with multileaf collimator apertures narrower than 10 mm defined as 'small') less than 0.2 also identified QA passing IMRT beams with 100% specificity. However, few of the metrics are correlated with the results from QA testing of the VMAT beams, whether they were evaluated as whole 360° arcs or as 60° sub-arcs. Select evaluation of beam complexity metrics (at least MI, MCS and SAS) is therefore recommended, as an intermediate step in the IMRT QA chain. Such evaluation may also be useful as a means of periodically reviewing VMAT planning or optimiser performance.

Mammary glands in male marsupials. 2. Development of teat primordia in Didelphis virginiana and Monodelphis domestica

Publisher: CSIRO Publishing

Date: 1991

DOI: 10.1071/RD9910295

Abstract: Young and adults of both sexes of two didelphid marsupials, Didelphis virginiana and Monodelphis domestica, were examined externally for evidence of mammary gland development. Female young possessed teat numbers typical of adult females (13-15 in D. virginiana 11-13 in M. domestica). Male young showed variable teat numbers which were always low compared with females, with the majority possessing 2-4 in anterior positions. Teats were also present in adult males of both species, in similar numbers and locations to those of young males. There are no previous reports of the presence of teats in any adult male marsupials. No mammary primordia in males have been recorded at any stage of development in the most thoroughly studied Australian marsupials. Our findings strengthen the view that there is a dichotomy between the two marsupial lineages in the regulation of male mammary gland expression.

Ontogeny and pathway of formation of 5α-androstane-3α,17β-diol in the testes of the immature brushtail possum Trichosurus vulpecula

Publisher: CSIRO Publishing

Date: 2005

DOI: 10.1071/RD05034

Abstract: The testicular androgen 5α-androstane-3α,17β-diol (androstanediol) mediates virilisation in pouch young of a marsupial, the tammar wallaby, and is the principal androgen formed in immature rodent testes. To chart the pattern of androstanediol formation in another marsupial species, the testes or fragments of testes from brushtail possums (Trichosurus vulpecula) that spanned the age range from early pouch young to mature adults were incubated with 3H-progesterone and the products were identified by high-performance liquid chromatography. The only 19-carbon steroids identified in pouch young and adult testes were the Δ4-3-keto-steroids testosterone and androstenedione. However, androstanediol and another 5α-reduced androgen (androsterone) were synthesised by testes from Day 87–200 males and these appeared to be formed from the 5α-reduction and 3-keto reduction of testosterone and androstenedione. In the prostate and glans penis of the immature male, 3H-androstanediol was converted to dihydrotestosterone. We conclude that the timing of androstanediol formation in the possum testis resembles the process in rodents rather than in the tammar wallaby and that any androstanediol in the circulation probably acts in target tissues via conversion to dihydrotestosterone.

Effects of progesterone on parturition in the tammar, Macropus eugenii

Publisher: Bioscientifica

Date: 09-1984

DOI: 10.1530/JRF.0.0720021

Abstract: Tammar wallabies were treated with progesterone injections or implants during late pregnancy to determine whether progesterone withdrawal was essential for parturition. Neither physiological (implanted group) nor pharmacological (injected group) levels of circulating progesterone prevented parturition occurring at about the expected time in about two-thirds of animals that were pregnant. The neonates of both groups were normal in size and weight, but about a third of treated pregnant animals retained their fetuses or aborted. The retained fetuses were retarded in development. Therefore, progesterone treatment had no influence on the duration of gestation, or parturition, in the tammar wallaby, but high progesterone concentrations may interfere with the normal course of development and birth in a proportion of treated animals.

Radiotherapy Monte Carlo simulation using cloud computing technology

Publisher: Springer Science and Business Media LLC

Date: 28-11-2012

DOI: 10.1007/S13246-012-0167-8

Abstract: Cloud computing allows for vast computational resources to be leveraged quickly and easily in bursts as and when required. Here we describe a technique that allows for Monte Carlo radiotherapy dose calculations to be performed using GEANT4 and executed in the cloud, with relative simulation cost and completion time evaluated as a function of machine count. As expected, simulation completion time decreases as 1/n for n parallel machines, and relative simulation cost is found to be optimal where n is a factor of the total simulation time in hours. Using the technique, we demonstrate the potential usefulness of cloud computing as a solution for rapid Monte Carlo simulation for radiotherapy dose calculation without the need for dedicated local computer hardware as a proof of principal.

Transcriptomic Analysis of MAP3K1 and MAP3K4 in the Developing Marsupial Gonad

Publisher: S. Karger AG

Date: 2019

DOI: 10.1159/000505799

Abstract: MAPKs affect gonadal differentiation in mice and humans, but whether this applies to all mammals is as yet unknown. Thus, we investigated MAPK expression during gonadal differentiation and after treatment with oestrogen in a distantly related mammal, the marsupial tammar wallaby, using our model of oestrogen-induced gonadal sex reversal. High-throughput RNA-sequencing was carried out on gonads collected from developing tammar 2 days before birth to 8 days after birth to characterise MAPK and key sexual differentiation markers. Day 25 foetal testes were cultured for 120 h in control medium or medium supplemented with exogenous oestrogen and processed for RNA-seq to identify changes in gene expression in response to oestrogen. MAPK pathway genes in the tammar were highly conserved at the sequence and amino acid level with those of mice and humans. Marsupial MAP3K1 and MAP3K4 clustered together in a separate branch from eutherian mammals. There was a marked decrease in the expression of male-determining genes i SOX9 /i and i AMH /i and increase in the female marker i FOXL2 /i in oestrogen-treated male gonads. Only i MAP3K1 /i expression increased in male gonads in response to oestrogen while other MAPK genes remained unaffected. This study suggests that MAP3K1 can be influenced by exogenous oestrogens during gonadal differentiation in this marsupial.

Ultrastructural characteristics of primordial germ cells and their amoeboid movement to the gonadal ridges in the tammar wallaby

Publisher: Springer Science and Business Media LLC

Date: 30-04-1997

DOI: 10.1007/S004290050066

Abstract: The primordial germ cells (PGCs) of tammar wallaby fetuses are large cells with large nuclei. The cytoplasm of the PGCs contains characteristic spherical mitochondria and abundant ribosomes that make the cyoplasm appear dense. No permanent junctional complexes between PGCs and somatic cells were observed, and there were few cytoplasmic inclusions. The majority of migrating PGCs were observed outside the gonad in the dorsal mesentery and in the tissues adjacent to the gonad. The migrating PGCs have many finger-like, blunt pseudopodia, within which microfilament bundles are observed. The numerous dumbell-like PGCs with polarised cytoplasm suggest that the PGCs of this marsupial move to the gonadal ridges by amoeboid movement, but once the PGCs reach the gonadal ridge, they assume their more characteristic ovoid shape.

Changes in the Milk Proteins during Lactation in the Tammar Wallaby, Macropus eugenii

Publisher: CSIRO Publishing

Date: 1982

DOI: 10.1071/BI9820145

Abstract: S les of whey proteins from the milk of tammar wallabies, Macropus eugenii, were examined by acrylamide gel electrophoresis at all stages of lactation up to 280 days post partum. Whey albumin, ,B-globulin and y-globulin fractions had similar electrophoretic mobility to that of the equivalent serum protein fractions, but the proteins in the IX-globulin and pre-albumin regions differed markedly. The IX-globulins are presumed polymorphic because in iduals at the same stage of lactation showed great variability in these electrophoretic regions: up to five polymorphic bands were recognized. Milk proteins changed qualitatively throughout lactation, and in particular the concentration of the pre-albumin and IX-globulin fractions increased from approximately day 180 to the end of lactation. Total protein concentration of both whole milk and whey approximately doubled in the second half of lactation compared to the first half, reaching maximum mean values of 114 � 47 and 96 � 50 g 1- 1 , respectively. Whole milk contained consistently more protein than whey, presumably due to the casein it contains.

Growth and histology of ovarian follicles after cold storage in the tammar wallaby

Publisher: CSIRO Publishing

Date: 2006

DOI: 10.1071/RD06007

Abstract: Cold storage is a simple method for storing and transporting tissues and organs. The reliability of this method for maintaining structure and function of marsupial ovarian tissue was assessed using histological techniques and follicle culture. Tammar wallaby ovaries were placed in cold storage (phosphate-buffered saline at 4°C) for 24 or 48 h. Although necrotic changes were evident in the germinal epithelium, cortex and interstitial tissue after cold storage, there was little evidence of necrotic changes in ovarian follicles and oocytes appeared normal. Secondary follicles isolated from ovarian tissue after cold storage grew by a similar amount to non-stored follicles when cultured for 4 days in vitro, but no follicles from any group developed to tertiary follicles. Cold storage for up to 24 h had little obvious effect on the structure of ovarian tissue and follicles isolated from this tissue maintained their structure during culture. However, degeneration in culture increased with storage time and was significantly higher after cold storage for 48 h. As demonstrated in the tammar wallaby, cold storage has potential as a method for storage and transport of marsupial ovaries up to 24 h.

An investigation of the pre-irradiation temporal stability of PAGAT gel dosimeter

Publisher: IOP Publishing

Date: 11-2010

DOI: 10.1088/1742-6596/250/1/012019

Monotreme and marsupial reproduction

Publisher: CSIRO Publishing

Date: 1995

DOI: 10.1071/RD9951003

Abstract: Marsupials were regarded as curiosities by their early European discoverers, animals to be wondered at. Monotremes were even more surprising the platypus was such an amalgam of characters that it was thought to be a hoax. They were recognized very early as mammals that could make a major contribution to our understanding of reproductive processes, and work on marsupials at the turn of the century was much in evidence. It is, however, only in the past two decades, and especially in the past few years that marsupial research has regained this position. There is no doubt that future research will strengthen this contribution, but we are faced with serious conservation questions that must be solved if we are to maintain these wonderful animals as a resource for future generations.

Unique small RNA signatures uncovered in the tammar wallaby genome

Publisher: Springer Science and Business Media LLC

Date: 17-10-2012

DOI: 10.1186/1471-2164-13-559

Abstract: Small RNAs have proven to be essential regulatory molecules encoded within eukaryotic genomes. These short RNAs participate in a erse array of cellular processes including gene regulation, chromatin dynamics and genome defense. The tammar wallaby, a marsupial mammal, is a powerful comparative model for studying the evolution of regulatory networks. As part of the genome sequencing initiative for the tammar, we have explored the evolution of each of the major classes of mammalian small RNAs in an Australian marsupial for the first time, including the first genome-scale analysis of the newest class of small RNAs, centromere repeat associated short interacting RNAs (crasiRNAs). Using next generation sequencing, we have characterized the major classes of small RNAs, micro (mi) RNAs, piwi interacting (pi) RNAs, and the centromere repeat associated short interacting (crasi) RNAs in the tammar. We examined each of these small RNA classes with respect to the newly assembled tammar wallaby genome for gene and repeat features, salient features that define their canonical sequences, and the constitution of both highly conserved and species-specific members. Using a combination of miRNA hairpin predictions and co-mapping with miRBase entries, we identified a highly conserved cluster of miRNA genes on the X chromosome in the tammar and a total of 94 other predicted miRNA producing genes. Mapping all miRNAs to the tammar genome and comparing target genes among tammar, mouse and human, we identified 163 conserved target genes. An additional nine genes were identified in tammar that do not have an orthologous miRNA target in human and likely represent novel miRNA-regulated genes in the tammar. A survey of the tammar gonadal piRNAs shows that these small RNAs are enriched in retroelements and carry members from both marsupial and tammar-specific repeat classes. Lastly, this study includes the first in-depth analyses of the newly discovered crasiRNAs. These small RNAs are derived largely from centromere-enriched retroelements, including a novel SINE. This study encompasses the first analyses of the major classes of small RNAs for the newly completed tammar genome, validates preliminary annotations using deep sequencing and computational approaches, and provides a foundation for future work on tammar-specific as well as conserved, but previously unknown small RNA progenitors and targets identified herein. The characterization of new miRNA target genes and a unique profile for crasiRNAs has allowed for insight into multiple RNA mediated processes in the tammar, including gene regulation, species incompatibilities, centromere and chromosome function.

Early Expression of the Androgen Receptor in the Sertoli Cells of a Marsupial Coincides with Downregulation of Anti-Müllerian Hormone at the Time of Urogenital Virilization

Publisher: S. Karger AG

Date: 2009

DOI: 10.1159/000273263

Abstract: Anti-Müllerian hormone (AMH), responsible for the regression of Müllerian ducts, is strongly expressed by eutherian fetal and postnatal Sertoli cells. Both AMH and testosterone levels are high during the period of fetal reproductive tract virilization which occurs largely in utero in eutherian mammals. Taking advantage of the fact that differentiation of the urogenital tract occurs after birth in marsupials, we studied the ontogeny and regulation of i AMH /i in the tammar wallaby testis and related it to the expression of the androgen receptor in Sertoli cells. Testicular AMH expression was high between days 10–30 post partum, then fell to basal levels by day 60 and remained low until day 90, the oldest age examined. AMH expression was repressed by treatment of male pouch young with the potent androgen androstanediol. Thus, in the tammar, AMH expression decreases in response to androgen at the time of initial urogenital masculinization, in contrast to the situation in humans in which AMH is repressed by testosterone only at the time of puberty. The difference might be explained by the timing of androgen receptor expression which appears in tammar Sertoli cells at around day 40 of pouch life but only at a later developmental stage in eutherians.

A-kinase anchoring protein 4 has a conserved role in mammalian spermatogenesis

Publisher: Bioscientifica

Date: 04-2009

DOI: 10.1530/REP-08-0337

Abstract: A-kinase anchor protein 4 (AKAP4) is an X -linked member of the AKAP family of scaffold proteins that anchor cAMP-dependent protein kinases and play an essential role in fibrous sheath assembly during spermatogenesis and flagellar function in spermatozoa. Marsupial spermatozoa differ in structural organization from those of eutherian mammals but data on the molecular control of their structure and function are limited. We therefore cloned and characterized the AKAP4 gene in a marsupial, the tammar wallaby ( Macropus eugenii ). The gene structure, sequence, and predicted protein of AKAP4 were highly conserved with that of eutherian orthologues and it mapped to the marsupial X-chromosome. There was no AKAP4 expression detected in the developing young. In the adult, AKAP4 expression was limited to the testis with a major transcript of 2.9 kb. AKAP4 mRNA was expressed in the cytoplasm of round and elongated spermatids while its protein was found on the principal piece of the flagellum in the sperm tail. This is consistent with its expression in other mammals. Thus, AKAP4 appears to have a conserved role in spermatogenesis for at least the last 166 million years of mammalian evolution.

Steroid metabolism by the placenta, corpus luteum and endometrium during pregnancy in the marsupial Macropus eugenii

Publisher: Elsevier BV

Date: 10-1977

DOI: 10.1016/0093-691X(77)90126-1

The human sex-reversing ATRX gene has a homologue on the marsupial Y chromosome, ATRY: Implications for the evolution of mammalian sex determination

Publisher: Proceedings of the National Academy of Sciences

Date: 07-11-2000

DOI: 10.1073/PNAS.230424497

Abstract: Mutations in the ATRX gene on the human X chromosome cause X-linked α-thalassemia and mental retardation. XY patients with deletions or mutations in this gene display varying degrees of sex reversal, implicating ATRX in the development of the human testis. To explore further the role of ATRX in mammalian sex differentiation, the homologous gene was cloned and characterized in a marsupial. Surprisingly, active homologues of ATRX were detected on the marsupial Y as well as the X chromosome. The Y-borne copy ( ATRY ) displays testis-specific expression. This, as well as the sex reversal of ATRX patients, suggests that ATRY is involved in testis development in marsupials and may represent an ancestral testis-determining mechanism that predated the evolution of SRY as the primary mammalian male sex-determining gene. There is no evidence for a Y-borne ATRX homologue in mouse or human, implying that this gene has been lost in eutherians and its role supplanted by the evolution of SRY from SOX3 as the dominant determiner of male differentiation.

Plasma progesterone secretion during gestation of the captive short-beaked echidna

Publisher: Bioscientifica

Date: 10-2021

DOI: 10.1530/REP-21-0110

Abstract: This study describes the progesterone profile during pregnancy in sexually mature female captive short-beaked echidnas ( Tachyglossus aculeatus aculeatus ). Echidnas were monitored daily by video surveillance to confirm key reproductive behaviour. Plasma s les were collected and pouch morphology was assessed three times a week. The pouch of the female echidna only develops during gestation and it was possible to create a four-stage grading system using the most distinguishable characteristics of pouch development. Maximum pouch development was associated with declining progesterone concentrations, with the pouch closing in a drawstring-like manner at oviposition. Control of pouch development in pregnant echidnas is not yet clear but later pouch development is associated with a decrease in progesterone and pouch closure and may be under mechanical influences of the egg or young in the pouch. The length of pregnancy was 16.7 ± 0.2 days with a 15.1 ± 1.0 days luteal phase followed by an incubation period in the pouch. Eggs could be detected in utero at least 4 days before oviposition. Plasma progesterone peaked at 10.5 ± 0.9 ng/mL within 12 days of mating but then declined to basal levels within 1 day of oviposition and remained basal throughout egg incubation, confirming that progesterone is elevated throughout pregnancy and that gestation does not extend beyond the luteal phase. After the loss of an egg or pouch young, most females entered a second oestrous cycle and ovulated, suggesting echidnas are seasonally polyoestrous. The duration of the luteal phase in the echidna corresponds with that observed in other mammals.

Bulk evaluation and comparison of radiotherapy treatment plans for breast cancer

Publisher: Springer Science and Business Media LLC

Date: 20-06-2016

DOI: 10.1007/S13246-016-0454-X

Abstract: This study provides a bulk, retrospective analysis of 151 breast and chest wall radiotherapy treatment plans, as a small-scale demonstration of the potential breadth and value of the information that may be obtained from clinical data mining. The treatments were planned at three centres belonging to one organisation over a period of 3 months. All 151 plans were used to evaluate inter-centre consistency and compliance with a local planning protocol. A subset of 79 plans, from one centre, were used in a more detailed evaluation of the effects of anatomical asymmetry on heart and lung dose, the effects of a metallic temporary tissue expander port on dose homogeneity and the overall conformity and homogeneity achieved in routine breast treatment planning. Differences in anatomical structure contouring and nomenclature were identified between the three centres, with all centres showing some non-compliance with the local planning protocol. When evaluated against standard conformity indices, these breast plans performed relatively poorly. However, when evaluated against recommended organ-at-risk tolerances, all evaluated plans performed sufficiently well that tighter planning tolerances could be recommended for future planning. Heart doses calculated in left breast and chest wall treatments were significantly higher than heart doses calculated in right sided breast and chest wall treatments (p < 0.001). In the treatment involving a temporary tissue expander, the inflated implant effectively pushed the targeted breast tissue away from the healthy tissues, leading to a dose distribution that was relatively conformal, although attenuation through the tissue expander's metallic port may have been underestimated by the treatment planning system. The results of this study exemplify the use of bulk treatment planning data to evaluate clinical workloads and inform ongoing treatment planning.

Hormonal and Molecular Regulation of Phallus Differentiation in a Marsupial Tammar Wallaby

Publisher: MDPI AG

Date: 16-01-2020

DOI: 10.3390/GENES11010106

Abstract: Congenital anomalies in phalluses caused by endocrine disruptors have gained a great deal of attention due to its annual increasing rate in males. However, the endocrine-driven molecular regulatory mechanism of abnormal phallus development is complex and remains largely unknown. Here, we review the direct effect of androgen and oestrogen on molecular regulation in phalluses using the marsupial tammar wallaby, whose phallus differentiation occurs after birth. We summarize and discuss the molecular mechanisms underlying phallus differentiation mediated by sonic hedgehog (SHH) at day 50 pp and phallus elongation mediated by insulin-like growth factor 1 (IGF1) and insulin-like growth factor binding protein 3 (IGFBP3), as well as multiple phallus-regulating genes expressed after day 50 pp. We also identify hormone-responsive long non-coding RNAs (lncRNAs) that are co-expressed with their neighboring coding genes. We show that the activation of SHH and IGF1, mediated by balanced androgen receptor (AR) and estrogen receptor 1 (ESR1) signalling, initiates a complex regulatory network in males to constrain the timing of phallus differentiation and to activate the downstream genes that maintain urethral closure and phallus elongation at later stages.

Treatment plan complexity metrics for predicting IMRT pre-treatment quality assurance results

Publisher: Springer Science and Business Media LLC

Date: 09-05-2014

DOI: 10.1007/S13246-014-0274-9

Abstract: The planning of IMRT treatments requires a compromise between dose conformity (complexity) and deliverability. This study investigates established and novel treatment complexity metrics for 122 IMRT beams from prostate treatment plans. The Treatment and Dose Assessor software was used to extract the necessary data from exported treatment plan files and calculate the metrics. For most of the metrics, there was strong overlap between the calculated values for plans that passed and failed their quality assurance (QA) tests. However, statistically significant variation between plans that passed and failed QA measurements was found for the established modulation index and for a novel metric describing the proportion of small apertures in each beam. The 'small aperture score' provided threshold values which successfully distinguished deliverable treatment plans from plans that did not pass QA, with a low false negative rate.

Developmentally regulated thyroid hormone distributor proteins in marsupials, a reptile, and fish

Publisher: American Physiological Society

Date: 05-2005

DOI: 10.1152/AJPREGU.00793.2004

Abstract: Thyroid hormones are essential for vertebrate development. There is a characteristic rise in thyroid hormone levels in blood during critical periods of thyroid hormone-regulated development. Thyroid hormones are lipophilic compounds, which readily partition from an aqueous environment into a lipid environment. Thyroid hormone distributor proteins are required to ensure adequate distribution of thyroid hormones, throughout the aqueous environment of the blood, and to counteract the avid partitioning of thyroid hormones into the lipid environment of cell membranes. In human blood, these proteins are albumin, transthyretin and thyroxine-binding globulin. We analyzed the developmental profile of thyroid hormone distributor proteins in serum from a representative of each order of marsupials ( M. eugenii S.crassicaudata), a reptile ( C. porosus), in two species of salmonoid fishes ( S. salar O. tshawytsch), and throughout a calendar year for sea bream ( S. aurata). We demonstrated that during development, these animals have a thyroid hormone distributor protein present in their blood which is not present in the adult blood. At least in mammals, this additional protein has higher affinity for thyroid hormones than the thyroid hormone distributor proteins in the blood of the adult. In fish, reptile and polyprotodont marsupial, this protein was transthyretin. In a diprotodont marsupial, it was thyroxine-binding globulin. We propose an hypothesis that an augmented thyroid hormone distributor protein network contributes to the rise in total thyroid hormone levels in the blood during development.

Embryo-endometrial interactions during early development after embryonic diapause in the marsupial tammar wallaby

Publisher: UPV/EHU Press

Date: 2014

DOI: 10.1387/IJDB.140059MR

Abstract: The marsupial tammar wallaby has the longest period of embryonic diapause of any mammal. Reproduction in the tammar is seasonal, regulated by photoperiod and also lactation. Reactivation is triggered by falling daylength after the austral summer solstice in December. Young are born late January and commence a 9-10-month lactation. Females mate immediately after birth. The resulting conceptus develops over 6- 7 days to form a unilaminar blastocyst of 80-100 cells and enters lactationally, and later seasonally, controlled diapause. The proximate endocrine signal for reactivation is an increase in progesterone which alters uterine secretions. Since the diapausing blastocyst is surrounded by the zona and 2 other acellular coats, the mucoid layer and shell coat, the uterine signals that maintain or terminate diapause must involve soluble factors in the secretions rather than any direct cellular interaction between uterus and embryo. Our studies suggest involvement of a number of cytokines in the regulation of diapause in tammars. The endometrium secretes platelet activating factor (PAF) and leukaemia inhibitory factor, which increase after reactivation. Receptors for PAF are low on the blastocyst during diapause but are upregulated at reactivation. Conversely, there is endometrial expression of the muscle segment homeobox gene MSX2 throughout diapause, but it is rapidly downregulated at reactivation. These patterns are consistent with those observed in diapausing mice and mink after reactivation, despite the very different patterns of endocrine control of diapause in these 3 ergent species. These common patterns suggest a similar underlying mechanism for diapause, perhaps common to all mammals, but which is activated in only a few.

Long-term effects of deslorelin implants on reproduction in the female tammer wallaby (Macropus eugenii)

Publisher: Bioscientifica

Date: 03-2005

DOI: 10.1530/REP.1.00432

Abstract: The contraceptive and endocrine effects of long-term treatment with implants containing the GnRH agonist deslorelin were investigated in female tammar wallabies ( Macropus eugenii ). Fertility was successfully inhibited for 515 ± 87 days after treatment with a 5 mg deslorelin implant ( n = 7), while control animals gave birth to their first young 159 ± 47 days after placebo implant administration ( n = 8). The duration of contraception was highly variable, ranging from 344 to 761 days. The strict reproductive seasonality in the tammar wallaby was maintained once the implant had expired. This inhibition of reproduction was associated with a significant reduction in basal LH concentrations and a cessation of oestrous cycles, as evidenced by low progesterone concentrations. There was evidence to suggest that some aspect of either blastocyst survival, luteal reactivation, pregnancy or birth may be affected by deslorelin treatment in some animals. These results show that long-term inhibition of fertility in the female tammar wallaby is possible using slow-release deslorelin implants. The effects of deslorelin treatment were fully reversible and there was no evidence of negative side effects. Slow-release GnRH agonist implants may represent a practicable method for reproductive management of captive and semi-wild populations of marsupials.

Wolffian Duct Development

Publisher: S. Karger AG

Date: 2014

DOI: 10.1159/000363432

Abstract: The Wolffian ducts (WDs) are the progenitors of the epididymis, vas deferens and seminal vesicles. They form initially as nephric ducts that acquire connection to the developing testis as the mesonephros regresses. The development of the WDs is dependent on androgens. Conventionally, the active androgen is believed to be testosterone delivered locally rather than via the systemic circulation. However, recent studies in marsupials show that 5α-reduced steroids are essential and that these can induce virilisation even when they are delivered via the systemic circulation. The development of the WDs involves an interplay between the duct epithelium and underlying mesenchyme androgen receptors in both the epithelium and mesenchyme are needed. The epidermal growth factor and epidermal growth factor receptor may play a role, possibly via activation of androgen receptor. The formation of the epididymis involves a complex morphogenetic program to achieve the normal pattern of coiling, formation of septae, and regional functional differentiation. In part, this process may be mediated by inhibin beta A as well as by genes from the i HOX /i cluster. Whilst the development of the WD is androgen dependent, it is clear that there is a complex interplay between androgens, genes and growth factors in the tissues that leads to the formation of the complex anatomy of the male reproductive duct system in the adult.

Uterine flushing proteome of the tammar wallaby after reactivation from diapause

Publisher: Bioscientifica

Date: 11-2016

DOI: 10.1530/REP-16-0154

Abstract: The marsupial tammar wallaby has the longest period of embryonic diapause of any mammal, up to 11 months, during which there is no cell ision or blastocyst growth. Since the blastocyst in diapause is surrounded by acellular coats, the signals that maintain or terminate diapause involve factors that reside in uterine secretions. The nature of such factors remains to be resolved. In this study, uterine flushings (UFs) were used to assess changes in uterine secretions of tammars using liquid chromatography–mass spectrometry (LC–MS/MS) during diapause (day 0 and 3) and reactivation days (d) 4, 5, 6, 8, 9, 11 and 24 after removal of pouch young (RPY), which initiates embryonic development. This study supports earlier suggestions that the presence of specific factors stimulate reactivation, early embryonic growth and cell proliferation. A mitogen, hepatoma-derived growth factor and soluble epidermal growth factor receptors were observed from d3 until at least d11 RPY when these secreted proteins constituted 21% of the UF proteome. Binding of these factors to specific cellular receptors or growth factors may directly stimulate DNA synthesis and ision in endometrial gland cells. Proteins involved in the p53/CDKN1A (p21) cell cycle inhibition pathway were also observed in the diapause s les. Progesterone and most of the oestrogen-regulated proteins were present in the UF after d3, which is concomitant with the start of blastocyst mitoses at d4. We propose that once the p21 inhibition of the cell cycle is lost, growth factors including HDGF and EGFR are responsible for reactivation of the diapausing blastocyst via the uterine secretions.

Marsupial WT1 Has a Novel Isoform and Is Expressed in Both Somatic and Germ Cells in the Developing Ovary and Testis

Publisher: S. Karger AG

Date: 2007

DOI: 10.1159/000102106

Abstract: The Wilms‘ tumour 1 gene is essential for the formation of the mouse and human urogenital systems. We characterised this gene and examined its expression throughout gonadal development in a marsupial, the tammar wallaby. WT1 protein was detected in the Sertoli and granulosa cells of the developing testis and ovary, respectively. There was also strong immunostaining in the germ cells of both males and females at all stages of gonadal development. In the adult gonads WT1 appears to be dynamically regulated during spermatogenesis and oogenesis. Tammar WT1 has a novel isoform in which a portion of exon 1 is removed, partially deleting the RNA recognition motif (RRM). Despite its removal, WT1 still localised to RNA rich regions of the oocyte including speckled bodies within the nucleus, in the nucleolus and the perinucleolar compartment. This suggests that the RRM is not required for WT1 co-localisation with RNA. This is also the first report of WT1 in association with the perinucleolar compartment, important for RNA metabolism. Our data suggest that WT1 has a conserved function in both the somatic and germ cell lineages of the gonads of marsupials.

Clozapine bioactivation induces dose-dependent, drug-specific toxicity of human bone marrow stromal cells: A potential in vitro system for the study of agranulocytosis

Publisher: Elsevier BV

Date: 09-2006

DOI: 10.1016/J.BCP.2006.06.006

Abstract: Clozapine, an atypical antipsychotic drug effective in treatment of refractory schizophrenia causes potentially life-threatening agranulocytosis. The drug undergoes bioactivation to a toxic, chemically reactive intermediate with capacity to target stromal cells, central components of the bone marrow microenvironment implicated in neutrophil development. To identify possible mechanisms underpinning disruption of stroma as a site of drug bioactivation, toxicity was induced in vitro. Therefore metabolite generation procedures utilizing HOCl or HRP-H(2)O(2) as primary components involved in clozapine metabolism were adapted for stromal culture and coupled with viability determinations. Drug oxidation by HOCl was less toxic to stromal cells than HRP-H(2)O(2) based methods. More specifically, clozapine bioactivation by HRP-H(2)O(2) caused dose-dependent inhibition of stromal viability at therapeutically relevant concentrations. Differences in susceptibility of HAS303 and LP101 cells to the clozapine nitrenium ion were also evident. Stromal cell death was attributed to clozapine in the presence of a complete metabolising system comprising HRP and H(2)O(2). In the absence of a complete metabolising system clozapine was not cytotoxic. For LP101 cells, drug plus HRP (minus H(2)O(2)) also induced toxicity. Importantly, other antipsychotic drugs including risperidone, olanzapine and haloperidol when bioactivated, were not cytotoxic, indicating system specificity for clozapine. Exogenous GSH, N-acetylcysteine, l-ascorbic acid, catalase, and sodium azide afforded protection to cells whereas S-methylGSH, GSSG, ketoprofen and proadifen did not. Thus functional data derived from the in vitro stromal system defined in these studies may enable further investigation of the mechanisms subserving stromal impairment in clozapine-induced agranulocytosis and direct attention to improved methods for its prevention.

Sexual differentiation of the urogenital system of the fetal and neonatal tammar wallaby, Macropus eugenii

Publisher: Springer Science and Business Media LLC

Date: 08-1996

DOI: 10.1007/BF00195006

Abstract: Extreme weather events, like high temperatures and droughts, are predicted to become common with climate change, and may negatively impact plant growth. How honey bees (Apis mellifera L. [Hymenoptera: Apidae]) will respond to this challenge is unclear, especially when collecting pollen, their primary source of protein, lipids, and micro-nutrients. We explored this response with a data set from multiple research projects that measured pollen collected by honey bees during 2015-2017 in which above-average temperatures and a drought occurred in 2017. We summarized the abundance and ersity of pollen collected from July to September in replicated apiaries kept at commercial soybean and corn farms in Iowa, in the Midwestern USA. The most commonly collected pollen was from clover (Trifolium spp. [Fabales: Fabaceae]), which dramatically declined in absolute and relative abundance in July 2017 during a period of high temperatures and drought. Due to an apparent lack of clover, honey bees switched to the more drought-tolerant native species (e.g., Chamaecrista fasciculata [Michx.] Greene [Fabales: Fabaceae], Dalea purpurea Vent. [Fabales: Fabaceae], Solidago spp. [Asterales: Asteraceae]), and several species of Asteraceae. This was especially noticeable in August 2017 when C. fasciculata dominated (87%) and clover disappeared from bee-collected pollen. We discuss the potential implications of climate-induced forage dearth on honey bee nutritional health. We also compare these results to a growing body of literature on the use of native, perennial flowering plants found in Midwestern prairies for the conservation of beneficial insects. We discuss the potential for drought resistant-native plants to potentially promote resilience to climate change for the non-native, managed honey bee colonies in the United States.

Sperm transport, size of the seminal plug and the timing of ovulation after natural mating in the female tammar wallaby Macropus eugenii

Publisher: CSIRO Publishing

Date: 2004

DOI: 10.1071/RD04089

Abstract: The distribution of spermatozoa and seminal plug in the reproductive tract and the timing of ovulation were examined at various times in a naturally mated monovular macropodid marsupial, namely the tammar wallaby (Macropus eugenii). After the first post partum (p.p.) mating, 28 females were isolated and their reproductive tracts dissected at 0.5, 6, 18, 36 and 40 h post coitum (p.c.). Each tract was ligated into 13 major anatomical sections and spermatozoa and eggs were recovered by flushing. Mating was possibly delayed by handling and occurred 21.7 ± 2.5 h p.p. in these animals. Copulation lasted 7.8 ± 0.7 min. Within 0.5 h after a single mating, the tract contained 25.8 ± 10.2 × 106 spermatozoa and 21.6 ± 8.8 g of seminal plug, 96% and 70% of which was lost within 6 h p.c. respectively. Spermatozoa reached the uterus, isthmus and ulla of the oviduct on the side of the developing follicle within 0.5, 6 and 18 h p.c., respectively, and a uterine population of 26.1 ± 12.103 spermatozoa was maintained for over 40 h. Sperm numbers were reduced at the cervix (up to 57-fold) and uterotubule junction (eight-fold) and only one in approximately 7500 ejaculated spermatozoa (3.4 ± 0.9 × 103) reached the oviduct on the follicle side. Differential transport of spermatozoa was not observed. Although the numbers of spermatozoa were reduced in the parturient uterus, they were highly variable and were not significantly different to those in the non-parturient uterus. Ovulation and recovery of sperm-covered eggs from the isthmus occurred 36–41 h p.c. (49–72 h p.p.). In contrast with the polyovular dasyurid and didelphid marsupials, the tammar wallaby ejaculates large numbers of spermatozoa, but transport is relatively inefficient and sperm storage in the tract before ovulation is limited.

Goα Expression in the Vomeronasal Organ and Olfactory Bulb of the Tammar Wallaby

Publisher: Oxford University Press (OUP)

Date: 03-2012

DOI: 10.1093/CHEMSE/BJS040

Abstract: The vomeronasal organ (VNO) detects pheromones via 2 large families of receptors: vomeronasal receptor 1, associated with the protein Giα2, and vomeronasal receptor 2, associated with Goα. We investigated the distribution of Goα in the developing and adult VNO and adult olfactory bulb of a marsupial, the tammar wallaby. Some cells expressed Goα as early as day 5 postpartum, but by day 30, Goα expressing cells were distributed throughout the receptor epithelium of the VNO. In the adult tammar, Goα appeared to be expressed in sensory neurons whose nuclei were mostly basally located in the vomeronasal receptor epithelium. Goα expressing vomeronasal receptor cells led to all areas of the accessory olfactory bulb (AOB). The lack of regionally restricted projection of the vomeronasal receptor cell type 2 in the tammar was similar to the uniform type, with the crucial difference that the uniform type only shows expression of Giα2 and no expression of Goα. The observed Goα staining pattern suggests that the tammar may have a third accessory olfactory type that could be intermediate to the segregated and uniform types already described.

Pollen Loads of Honey Possums (Tarsipes Spenserae) and Nonflying Mammal Pollination in Southwestern Australia

Publisher: JSTOR

Date: 1979

DOI: 10.2307/2398921

Rewinding the process of mammalian extinction

Publisher: Wiley

Date: 03-05-2016

DOI: 10.1002/ZOO.21284

Abstract: With only three living in iduals left on this planet, the northern white rhinoceros (Ceratotherium simum cottoni) could be considered doomed for extinction. It might still be possible, however, to rescue the (sub)species by combining novel stem cell and assisted reproductive technologies. To discuss the various practical options available to us, we convened a multidisciplinary meeting under the name "Conservation by Cellular Technologies." The outcome of this meeting and the proposed road map that, if successfully implemented, would ultimately lead to a self-sustaining population of an extremely endangered species are outlined here. The ideas discussed here, while centered on the northern white rhinoceros, are equally applicable, after proper adjustments, to other mammals on the brink of extinction. Through implementation of these ideas we hope to establish the foundation for reversal of some of the effects of what has been termed the sixth mass extinction event in the history of Earth, and the first anthropogenic one. Zoo Biol. 35:280-292, 2016. © 2016 The Authors. Zoo Biology published by Wiley Periodicals, Inc.

A new role for muscle segment homeobox genes in mammalian embryonic diapause

Publisher: The Royal Society

Date: 04-2013

DOI: 10.1098/RSOB.130035

Abstract: Mammalian embryonic diapause is a phenomenon defined by the temporary arrest in blastocyst growth and metabolic activity within the uterus which synchronously becomes quiescent to blastocyst activation and implantation. This reproductive strategy temporally uncouples conception from parturition until environmental or maternal conditions are favourable for the survival of the mother and newborn. The underlying molecular mechanism by which the uterus and embryo temporarily achieve quiescence, maintain blastocyst survival and then resume blastocyst activation with subsequent implantation remains unknown. Here, we show that uterine expression of Msx1 or Msx2 , members of an ancient, highly conserved homeobox gene family, persists in three unrelated mammalian species during diapause, followed by rapid downregulation with blastocyst activation and implantation. Mice with uterine inactivation of Msx1 and Msx2 fail to achieve diapause and reactivation. Remarkably, the North American mink and Australian tammar wallaby share similar expression patterns of MSX1 or MSX2 as in mice — it persists during diapause and is rapidly downregulated upon blastocyst activation and implantation. Evidence from mouse studies suggests that the effects of Msx genes in diapause are mediated through Wnt5a, a known transcriptional target of uterine Msx . These studies provide strong evidence that the Msx gene family constitutes a common conserved molecular mediator in the uterus during embryonic diapause to improve female reproductive fitness.

Field size consistency of nominally matched linacs

Publisher: Springer Science and Business Media LLC

Date: 30-05-2015

DOI: 10.1007/S13246-015-0349-2

Abstract: Given that there is increasing recognition of the effect that sub-millimetre changes in collimator position can have on radiotherapy beam dosimetry, this study aimed to evaluate the potential variability in small field collimation that may exist between otherwise matched linacs. Field sizes and field output factors were measured using radiochromic film and an electron diode, for jaw- and MLC-collimated fields produced by eight dosimetrically matched Varian iX linacs (Varian Medical Systems, Palo Alto, USA). This study used nominal sizes from 0.6 × 0.6 to 10 × 10 cm(2), for jaw-collimated fields, and from 1 × 1 to 10 × 10 cm(2) for MLC-collimated fields, delivered from a zero (head up, beam directed vertically downward) gantry angle. Differences between the field sizes measured for the eight linacs exceeded the uncertainty of the film measurements and the repositioning uncertainty of the jaws and MLCs on one linac. The dimensions of fields defined by MLC leaves were more consistent between linacs, while also differing more from their nominal values than fields defined by orthogonal jaws. The field output factors measured for the different linacs generally increased with increasing measured field size for the nominal 0.6 × 0.6 to 1 × 1 cm(2) fields, and became consistent between linacs for nominal field sizes of 2 × 2 cm(2) and larger. The inclusion in radiotherapy treatment planning system beam data of small field output factors acquired in fields collimated by jaws (rather than the more-reproducible MLCs), associated with either the nominal or the measured field sizes, should be viewed with caution. The size and reproducibility of the fields (especially the small fields) used to acquire treatment planning data should be investigated thoroughly as part of the linac or planning system commissioning process. Further investigation of these issues, using different linac models, collimation systems and beam orientations, is recommended.

HOXA13 and HOXD13 expression during development of the syndactylous digits in the marsupial Macropus eugenii

Publisher: Springer Science and Business Media LLC

Date: 11-01-2012

DOI: 10.1186/1471-213X-12-2

Abstract: Kangaroos and wallabies have specialised limbs that allow for their hopping mode of locomotion. The hindlimbs differentiate much later in development but become much larger than the forelimbs. The hindlimb autopod has only four digits, the fourth of which is greatly elongated, while digits two and three are syndactylous. We investigated the expression of two genes, HOXA13 and HOXD13 , that are crucial for digit patterning in mice during formation of the limbs of the tammar wallaby. We describe the development of the tammar limbs at key stages before birth. There was marked heterochrony and the hindlimb developed more slowly than the forelimb. Both tammar HOXA13 and HOXD13 have two exons as in humans, mice and chickens. HOXA13 had an early and distal mRNA distribution in the tammar limb bud as in the mouse, but forelimb expression preceded that in the hindlimb. HOXD13 mRNA was expressed earlier in the forelimb than the hindlimb and was predominantly detected in the interdigital tissues of the forelimb. In contrast, the hindlimb had a more restricted expression pattern that appeared to be expressed at discrete points at both posterior and anterior margins of the limb bud, and was unlike expression seen in the mouse and the chicken. This is the first examination of HOXA and HOXD gene expression in a marsupial. The gene structure and predicted proteins were highly conserved with their eutherian orthologues. Interestingly, despite the morphological differences in hindlimb patterning, there were no modifications to the polyalanine tract of either HOXA13 or HOXD13 when compared to those of the mouse and bat but there was a marked difference between the tammar and the other mammals in the region of the first polyserine tract of HOXD13 . There were also altered expression domains for both genes in the developing tammar limbs compared to the chicken and mouse. Together these findings suggest that the timing of HOX gene expression may contribute to the heterochrony of the forelimb and hindlimb and that alteration to HOX domains may influence phenotypic differences that lead to the development of marsupial syndactylous digits.

The AASM 2012 recommended hypopnea criteria increase the incidence of obstructive sleep apnea but not the proportion of positional obstructive sleep apnea

Publisher: Elsevier BV

Date: 10-2016

DOI: 10.1016/J.SLEEP.2016.07.013

Abstract: This study compared the effects of using the 2007 and 2012 American Academy of Sleep Medicine (AASM) recommended hypopnea criteria on the proportion of positional obstructive sleep apnea (pOSA). The effect of modifying the minimum recording time in each sleeping position on the proportion of pOSA was also investigated. 207 of 303 consecutive patients (91 of 207 were female) participated in polysomnography (PSG) for the suspicion of OSA met the inclusion criteria for this retrospective investigation. PSGs were scored for both the 2007 AASM recommended hypopnea criteria (AASM The AASM This study demonstrates that, compared to AASM

Postnatal lung and metabolic development in two marsupial and four eutherian species

Publisher: Wiley

Date: 31-01-2008

DOI: 10.1111/J.1469-7580.2007.00849.X

Sex determining genes and sexual differentiation in a marsupial

Publisher: Wiley

Date: 2001

DOI: 10.1002/JEZ.1109

Abstract: The role of genes in the differentiation of the testis and ovary has been extensively studied in the human and the mouse. Despite over a decade of investigations, the precise roles of genes and their interactions in the pathway of sex determination are still unclear. We have chosen to take a comparative look at sex determination and differentiation to gain insights into the evolution and the conserved functions of these genes. To achieve this, we have examined a wide variety of eutherian sex determining genes in a marsupial, the tammar wallaby, to determine which genes have a conserved and fundamental mammalian sex determining role. These investigations have provided many unique insights. Here, we review the recent molecular and endocrine investigations into sexual development in marsupials, and highlight how these studies have shed light on the roles of genes and hormones in mammalian sex determination and differentiation.

In-vitro comparison of volumetric and areal bone mineral density measurements between ultrasound transit time spectroscopy and microcomputed tomography

Publisher: Elsevier BV

Date: 08-2021

DOI: 10.1016/J.APACOUST.2021.108072

Power electronic converters for high power ultrasound transducers

Publisher: IEEE

Date: 07-2012

DOI: 10.1109/ICIEA.2012.6360806

The development of the gubernaculum and inguinal closure in the marsupial Macropus eugenii

Publisher: Wiley

Date: 09-2002

DOI: 10.1046/J.1469-7580.2002.00087.X

Abstract: This study reports the developmental anatomy of testicular descent and inguinal closure of the tammar wallaby (Macropus eugenii) from birth to maturity. In females the ovary migrated caudally between days 10 and 20 after birth. The gubernaculum differentiates into the round ligament in the abdomen and extra-abdominally as the ilio-marsupialis muscle of the mammary glands. In males the testes migrated to the internal inguinal ring by day 20 post partum (pp), coinciding with the enlargement of the gubernaculum, and from the internal inguinal ring to the scrotum between days 20 and 65 pp. During descent there was an increase in the hyaluronic acid concentration in cells of the gubernaculum and scrotum. Development of the cremaster muscle began by day 10 pp on the periphery of the gubernaculum and its basic structure was completed by day 60 pp. After descent the inguinal canal closed between days 50 and 60 pp, but a small irregular lumen persisted, somewhat similar to that seen in the congenital scrotal hydrocoele of humans. Tammars have a hopping mode of locomotion and, like humans, are essentially bipedal. We suggest that inguinal closure evolved in these two species because their upright posture may otherwise lead to a high incidence of inguinal hernias.

Mammary gland lactose, plasma progesterone and lactogenesis in the marsupial Macropus eugenii

Publisher: Bioscientifica

Date: 06-1983

DOI: 10.1677/JOE.0.0970425

Abstract: Mammary gland lactose concentrations in pregnant tammar wallabies remained low at 115 ± ( s.e.m. ) μg/g wet weight of tissue until immediately before parturition, then increased to 1274±262 μg/g after birth. Concentrations in non-pregnant cyclic animals were generally low 143±36 μg/g), but were raised in three animals around the time of oestrus. Removal of the corpus luteum on day 18 of pregnancy or the oestrous cycle caused an increase in lactose concentrations in both lutectomized and sham-operated animals. This occurred despite a significant lowering of peripheral plasma progesterone concentration in only the lutectomized group. Plasma cortisol concentrations were high in some of these animals, but showed no consistent relationships with the raised lactose concentrations. The increased peripartum lactose concentration normally coincides with a sharp fall in peripheral plasma progesterone concentration, but artificial maintenance of high progesterone levels had no effect on the increase of mammary gland lactose at parturition. Mammary gland lactose concentrations in tammar wallabies are therefore a useful indicator of biosynthetic activity and as an index of lactogenesis but the role, if any, of progesterone withdrawal in lactogenesis remains unclear.

Transient role of the middle ear as a lower jaw support across mammals

Publisher: eLife Sciences Publications, Ltd

Date: 30-06-2020

DOI: 10.7554/ELIFE.57860

Abstract: Mammals articulate their jaws using a novel joint between the dentary and squamosal bones. In eutherian mammals, this joint forms in the embryo, supporting feeding and vocalisation from birth. In contrast, marsupials and monotremes exhibit extreme altriciality and are born before the bones of the novel mammalian jaw joint form. These mammals need to rely on other mechanisms to allow them to feed. Here, we show that this vital function is carried out by the earlier developing, cartilaginous incus of the middle ear, abutting the cranial base to form a cranio-mandibular articulation. The nature of this articulation varies between monotremes and marsupials, with juvenile monotremes retaining a double articulation, similar to that of the fossil mammaliaform Morganucodon, while marsupials use a versican-rich matrix to stabilise the jaw against the cranial base. These findings provide novel insight into the evolution of mammals and the changing relationship between the jaw and ear.

Murdoch University

Location: Australia

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University Of Melbourne

Location: Australia

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Monash University

Location: Australia

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Australian National University

Location: Australia

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Pausing Pregnancy: The Convergent Evolution Of, And Mechanisms Underpinning Embryonic Diapause Observed Across Mammals.

Start Date: 2021

End Date: 2024

Funder: Marsden Fund

Discovery Projects - Grant ID: DP0344941

Start Date: 2003

End Date: 12-2007

Amount: $180,000.00

Funder: Australian Research Council

Federation Fellowships - Grant ID: FF0348625

Start Date: 2003

End Date: 12-2008

Amount: $1,450,370.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP0771017

Start Date: 2008

End Date: 12-2009

Amount: $263,000.00

Funder: Australian Research Council

Linkage Infrastructure, Equipment And Facilities - Grant ID: LE0667981

Start Date: 2006

End Date: 12-2007

Amount: $200,000.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP160101728

Start Date: 12-2017

End Date: 07-2022

Amount: $575,127.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP120101797

Start Date: 2012

End Date: 12-2015

Amount: $810,000.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP130102103

Start Date: 2013

End Date: 12-2016

Amount: $474,000.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP200101138

Start Date: 07-2020

End Date: 07-2025

Amount: $1,023,000.00

Funder: Australian Research Council

ARC Centres Of Excellence - Grant ID: CE0348205

Start Date: 2003

End Date: 12-2010

Amount: $5,271,140.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP200100344

Start Date: 10-2020

End Date: 10-2024

Amount: $760,000.00

Funder: Australian Research Council

Learned Academies Special Projects - Grant ID: LS140100016

Start Date: 10-2014

End Date: 12-2018

Amount: $474,334.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP0560344

Start Date: 04-2005

End Date: 12-2010

Amount: $1,400,000.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP0557834

Start Date: 2005

End Date: 12-2009

Amount: $350,000.00

Funder: Australian Research Council

Special Research Initiatives - Grant ID: SR0354861

Start Date: 03-2004

End Date: 10-2004

Amount: $15,000.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP0208497

Start Date: 2002

End Date: 12-2006

Amount: $395,000.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP160103683

Start Date: 2016

End Date: 12-2019

Amount: $682,100.00

Funder: Australian Research Council