ORCID Profile
0000-0002-8479-8819
Current Organisation
University of New Mexico
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Host-parasite interactions | Animal behaviour | Host-Parasite Interactions | Genetic Immunology | Ecology | Behavioural ecology | Population, Ecological and Evolutionary Genetics | Genetics
Sparseland, Permanent Grassland and Arid Zone Flora, Fauna and Biodiversity | Expanding Knowledge in the Biological Sciences |
Publisher: Elsevier BV
Date: 10-2013
DOI: 10.1016/J.VETPAR.2013.04.025
Abstract: One hundred and thirty four Little Penguin (Eudyptula minor) carcases found since 2004 in south west Australia were necropsied. The livers and spleens from ten of the penguins exhibited varying degrees of multifocal, randomly scattered areas of necrosis and varying numbers of parasites were associated with these areas. Hepatomegaly and splenomegaly were noted in many of these ten cases. Necrosis and parasites were also observed in the cardiac muscle of four of the cases and in the lung tissue in one of the penguins. Using PCR, the parasites were positively identified in four of the cases as Haemoproteus spp. and morphologically identical tissue stage parasites associated with histopathological changes were observed in all ten dead penguins. This is the first study to demonstrate both the in situ presence of the Haemoproteus parasite in any member of the Sphensicidae family and mortality due to its presence. We postulate the involvement of anomalous environmental conditions in a potential increase in local vectors.
Publisher: S. Karger AG
Date: 2006
DOI: 10.1159/000089882
Abstract: We used genetic linkage mapping and fluorescence in situhybridization (FISH) to conduct the first analysis of genic organization and chromosome localization of the major histocompatibility complex (MHC) of a marsupial, the gray, short-tailed opossum i Monodelphis domestica /i . Family based linkage analyses of two i M. domestica /i MHC Class I genes ( i UA1 /i , i UG /i ) and three MHC Class II genes ( i DAB /i , i DMA /i , and i DMB /i ) revealed that these genes were tightly linked and positioned in the central region of linkage group 3 (LG3). This cluster of MHC genes was physically mapped to the centromeric region of chromosome 2q by FISH using a BAC clone containing the i UA1 /i gene. An interesting finding from the linkage analyses is that sex-specific recombination rates were virtually identical within the MHC region. This stands in stark contrast to the genome-wide situation, wherein males exhibit approximately twice as much recombination as females, and could have evolutionary implications for maintaining equality between males and females in the ability to generate haplotype ersity in this region. These analyses also showed that three non-MHC genes that flank the MHC region on human chromosome 6, myelin oligodendrocyte glycoprotein ( i MOG /i ), bone morphogenetic protein 6 ( i BMP6 /i ), and prolactin ( i PRL /i ), are split among two separate linkage groups (chromosomes) in i M. domestica /i . Comparative analysis with eight other vertebrate species suggests strong conservation of the i BMP6 /i & #8211 i PRL /i synteny among birds and mammals, although the i BMP6& #8211 PRL& #8211 MHC& #8211 ME1 /i synteny is not conserved.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 26-03-2021
Abstract: The two established T cell lineages found in jawed vertebrates use either an αβ or a γδ T cell receptor (TCR) to detect antigens. Recently, another type of TCR chain (TCRµ) was found in marsupials and monotremes. Morrissey et al. analyzed T cells from the gray short-tailed opossum and uncovered a third lineage resident in the spleen that uses a γµ TCR (see the Perspective by Criscitiello). The authors then characterized the crystal structures of two different γµ TCRs, which exhibited an architecture distinct from αβ or γδ TCRs in which a highly erse, unpaired immunoglobulin-like variable domain was predicted to be the major antigen recognition determinant. Like camelid VHH and shark IgNAR antibodies, γµ TCRs could potentially inform future nanobody development. Science , this issue p. 1383 see also p. 1308
Publisher: S. Karger AG
Date: 2006
DOI: 10.1159/000089901
Publisher: The American Association of Immunologists
Date: 15-04-2022
Abstract: T lymphocytes or T cells are key components of the vertebrate response to pathogens and cancer. There are two T cell classes based on their TCRs, αβ T cells and γδ T cells, and each plays a critical role in immune responses. The squamate reptiles may be unique among the vertebrate lineages by lacking an entire class of T cells, the γδ T cells. In this study, we investigated the basis of the loss of the γδ T cells in squamates. The genome and transcriptome of a sleepy lizard, the skink Tiliqua rugosa, were compared with those of tuatara, Sphenodon punctatus, the last living member of the Rhynchocephalian reptiles. We demonstrate that the lack of TCRγ and TCRδ transcripts in the skink are due to large deletions in the T. rugosa genome. We also show that tuataras are on a growing list of species, including sharks, frogs, birds, alligators, and platypus, that can use an atypical TCRδ that appears to be a chimera of a TCR chain with an Ab-like Ag-binding domain. Tuatara represents the nearest living relative to squamates that retain γδ T cells. The loss of γδTCR in the skink is due to genomic deletions that appear to be conserved in other squamates. The genes encoding the αβTCR chains in the skink do not appear to have increased in complexity to compensate for the loss of γδ T cells.
Publisher: CSIRO Publishing
Date: 2009
DOI: 10.1071/ZO09042
Abstract: The sequencing of the platypus genome has spurred investigations into the characterisation of the monotreme immune response. As the most ergent of extant mammals, the characterisation of the monotreme immune repertoire allows us to trace the evolutionary history of immunity in mammals and provide insights into the immune gene complement of ancestral mammals. The immune system of monotremes has remained largely uncharacterised due to the lack of specific immunological reagents and limited access to animals for experimentation. Early immunological studies focussed on the anatomy and physiology of the lymphoid system in the platypus. More recent molecular studies have focussed on characterisation of in idual immunoglobulin, T-cell receptor and MHC genes in both the platypus and short-beaked echidna. Here, we review the published literature on the monotreme immune gene repertoire and provide new data generated from genome analysis on cytokines, Fc receptors and immunoglobulins. We present an overview of key gene families responsible for innate and adaptive immunity including the cathelicidins, defensins, T-cell receptors and the major histocompatibility complex (MHC) Class I and Class II antigens. We comment on the usefulness of these sequences for future studies into immunity, health and disease in monotremes.
Publisher: Springer Science and Business Media LLC
Date: 28-03-2006
DOI: 10.1007/S00251-006-0107-4
Abstract: The major histocompatibility complex (MHC) plays an essential role in the adaptive immune system of vertebrates through antigen recognition. Although MHC genes are found in all vertebrates, the MHC region is dynamic and has changed throughout vertebrate evolution, making it an important tool for comparative genomics. Marsupials occupy an important position in mammalian phylogeny, yet the MHC of few marsupials has been studied in detail. We report the isolation and analysis of expressed MHC Class I genes from the tammar wallaby, a model marsupial used extensively for the study of mammalian reproduction, genetics, and immunology. We determined that there are at least 11 Class I loci in the tammar genome and isolated six expressed Class I sequences from spleen and testes cDNA libraries, representing at least four loci. Two of the Class I sequences contain substitutions at sites known to be important for antigen binding, perhaps impacting their ability to bind peptides, or the types of peptide to which they bind. Phylogenetic analysis of tammar wallaby Class I sequences and other mammalian Class I sequences suggests that some tammar wallaby and red-necked wallaby loci evolved from common ancestral genes.
Publisher: Proceedings of the National Academy of Sciences
Date: 05-06-2007
Abstract: T cells recognize antigens by using T cell receptors (TCRs) encoded by gene segments, called variable (V), ersity (D), and joining (J), that undergo somatic recombination to create erse binding specificities. Four TCR chains (α, β, γ, and δ) have been identified to date, and, as T cells develop in the thymus, they express exclusively either an αβTCR or a γδTCR heterodimer. Here, we show that marsupials have an additional TCR (TCRμ) that has V, D, and J that are either somatically recombined, as in conventional TCRs, or are already prejoined in the germ-line DNA in a manner consistent with their creation by retrotransposition. TCRμ does not have a known homolog in eutherian mammals but has features analogous to a recently described TCRδ isoform in sharks. TCRμ is expressed in at least two mRNA isoforms that appear capable of encoding a full-length protein, both of which are transcribed in the thymus and spleen. One contains two variable domains: a somatically recombined V and a prejoined V. This appears to be the dominant isoform in peripheral lymphoid tissue. The other isoform contains only the prejoined V and is structurally more similar to conventional TCR chains, however invariant. Unlike other TCRs, TCRμ uses prejoined gene segments and is likely present in all marsupials. Its similarity to a TCR isoform in sharks suggests that it, or something similar, may be present in other vertebrate lineages and, therefore, may represent an ancient receptor system.
Publisher: Springer Science and Business Media LLC
Date: 02-2004
DOI: 10.1007/S00251-004-0644-7
Abstract: Genes of the major histocompatibility complex (MHC) have been characterized in all extant lineages of mammals. The tammar wallaby (Macropus eugenii) is well established as a model marsupial species however, no classical MHC sequences have been described from this species. We have isolated two MHC class II beta-chain sequences from a tammar wallaby spleen cDNA library using a tammar MHC class II beta probe. These sequences belong to the marsupial MHC class II DBB gene family. Two additional DBB sequences were lified from tammar wallaby genomic DNA. All four sequences were obtained from the same in idual, indicating that there are at least two DBB loci in the tammar wallaby.
Publisher: Springer Science and Business Media LLC
Date: 19-08-2011
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.
Publisher: Elsevier BV
Date: 12-2015
DOI: 10.1016/J.DCI.2015.07.012
Abstract: The major histocompatibility complex (MHC) is a highly variable region of vertebrate genomes that encodes cellular proteins involved in the immune response. In addition to the benefits of MHC research in understanding the genetic basis of host resistance to disease, the MHC is an ideal candidate for studying genetic ersity under strong natural selection. However, the MHC of many non-model vertebrate taxa are poorly characterized, hindering an understanding of disease resistance and its application to conservation genetics in these groups. Squamates (lizards and snakes) remain particularly underrepresented despite their being the most erse order of non-avian sauropsids. We characterized MHC class I sequence ersity from an Australian skink, the sleepy lizard (Tiliqua rugosa), using both cDNA and genomic sequence data and also present genomic class I sequences from the related skinks Tiliqua adelaidensis and Egernia stokesii. Phylogenetic analysis of Tiliqua and other published sqamate MHC class I sequences suggest that MHC erged very early in Tiliqua compared with the other studied squamates. We identified at least 4 classical MHC class I loci in T. rugosa and also shared polymorphism among T. rugosa, T. adelaidensis and E. stokesii in the sequences encoding peptide-binding α1 and α2 domains.
Publisher: CSIRO Publishing
Date: 2013
DOI: 10.1071/ZO12111
Abstract: Marsupial immune responses were previously touted as ‘primitive’ but we now know that the marsupial immune system is complex and on par with that of eutherian mammals. In this manuscript we review the field of marsupial immunology, focusing on basic anatomy, developmental immunology, immunogenetics and evolution. We concentrate on advances to our understanding of marsupial immune gene architecture, made possible by the recent sequencing of the opossum, tammar wallaby and Tasmanian devil genomes. Characterisation of immune gene sequences now paves the way for the development of immunological assays that will allow us to more accurately study health and disease in marsupials.
Publisher: Public Library of Science (PLoS)
Date: 31-01-2006
Publisher: Oxford University Press (OUP)
Date: 15-05-2012
Publisher: Public Library of Science (PLoS)
Date: 10-06-2014
Publisher: PeerJ
Date: 23-06-2020
DOI: 10.7717/PEERJ.9335
Abstract: All mammals are characterized by the ability of females to produce milk. Marsupial (metatherian) and monotreme (prototherian) young are born in a highly altricial state and rely on their mother’s milk for the first part of their life. Here we review the role and importance of milk in marsupial and monotreme development. Milk is the primary source of sustenance for young marsupials and monotremes and its composition varies at different stages of development. We applied nutritional geometry techniques to a limited number of species with values available to analyze changes in macronutrient composition of milk at different stages. Macronutrient energy composition of marsupial milk varies between species and changes concentration during the course of lactation. As well as nourishment, marsupial and monotreme milk supplies growth and immune factors. Neonates are unable to mount a specific immune response shortly after birth and therefore rely on immunoglobulins, immunological cells and other immunologically important molecules transferred through milk. Milk is also essential to the development of the maternal-young bond and is achieved through feedback systems and odor preferences in eutherian mammals. However, we have much to learn about the role of milk in marsupial and monotreme mother-young bonding. Further research is warranted in gaining a better understanding of the role of milk as a source of nutrition, developmental factors and immunity, in a broader range of marsupial species, and monotremes.
Publisher: Springer Science and Business Media LLC
Date: 05-2007
DOI: 10.1038/NATURE05805
Abstract: We report a high-quality draft of the genome sequence of the grey, short-tailed opossum (Monodelphis domestica). As the first metatherian ('marsupial') species to be sequenced, the opossum provides a unique perspective on the organization and evolution of mammalian genomes. Distinctive features of the opossum chromosomes provide support for recent theories about genome evolution and function, including a strong influence of biased gene conversion on nucleotide sequence composition, and a relationship between chromosomal characteristics and X chromosome inactivation. Comparison of opossum and eutherian genomes also reveals a sharp difference in evolutionary innovation between protein-coding and non-coding functional elements. True innovation in protein-coding genes seems to be relatively rare, with lineage-specific differences being largely due to ersification and rapid turnover in gene families involved in environmental interactions. In contrast, about 20% of eutherian conserved non-coding elements (CNEs) are recent inventions that postdate the ergence of Eutheria and Metatheria. A substantial proportion of these eutherian-specific CNEs arose from sequence inserted by transposable elements, pointing to transposons as a major creative force in the evolution of mammalian gene regulation.
Publisher: Springer Science and Business Media LLC
Date: 22-07-2015
Publisher: Elsevier BV
Date: 10-2021
DOI: 10.1016/J.DCI.2021.104141
Abstract: B-cells are key to humoral immunity, are found in multiple lymphoid organs, and have the unique ability to mediate the production of antigen-specific antibodies in the presence of pathogens. The marsupial immunoglobulin (Ig) heavy (H) chain locus encodes four constant region isotypes, IgA, IgG, IgM and IgE, but no IgD, and there are two light (L) chain isotypes, lambda (Igλ) and kappa (Igκ). To gain an understanding of the marsupial humoral immune system, B-cell transcriptomes generated by single-cell RNA sequencing from gray short-tailed opossum (Monodelphis domestica) splenocytes, and peripheral blood mononuclear cells were analysed. The cells used were from a single unimmunized animal and the majority of B-cells were transcribing IgM heavy chains. The ratio of Ig light chain use was roughly 2:1, Igλ:Igκ in this in idual. This was not predicted due to Igκ being the more complex of the two L chain loci. The variable (V) gene segment pairs used in in idual B-cells confirm greater ersity provided by the L chain V. This study is the first to report on using single cell analysis to investigate Ig repertoires in a marsupial and confirms a number of prior hypothesis, as well as revealing some surprises.
Publisher: S. Karger AG
Date: 2006
DOI: 10.1159/000091942
Start Date: 06-2020
End Date: 12-2023
Amount: $401,030.00
Funder: Australian Research Council
View Funded ActivityStart Date: 08-2023
End Date: 07-2026
Amount: $551,771.00
Funder: Australian Research Council
View Funded Activity