ORCID Profile
0000-0001-6959-9398
Current Organisation
NSW Department of Primary Industries
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Publisher: Hindawi Limited
Date: 19-01-2018
DOI: 10.1111/TBED.12817
Abstract: Chlamydia psittaci is an important avian pathogen with spillover from infected wild and domesticated birds also posing a risk to human health. We recently reported a case of C. psittaci equine placentitis associated with further spillover to humans. Molecular typing of this case revealed it belonged to the 6BC clade of C. psittaci, a globally distributed highly virulent set of strains, typically linked to infection spillover from parrots. Equine chlamydiosis associated with C. psittaci infection has previously been reported elsewhere in countries where parrots are not endemic, however, raising questions over the identity of infecting C. psittaci strains and the potential infection reservoirs. In this study, we describe the detection and molecular characterization of C. psittaci in a case of equine abortion in southern Queensland. Equine placenta and fresh liver and lung tissue from the necropsied foetus were positive by C. psittaci-specific qPCR. Chlamydia psittaci-specific multilocus sequence typing and ompA genotyping were used to further characterize the detected equine strains and an additional strain obtained from a dove from a different geographic region presenting with psittacosis. Molecular typing of this case revealed that the infecting equine strains were closely related to the C0sittaci detected in dove, all belonging to an evolutionary lineage of C. psittaci strains typically associated with infections of pigeons globally. This finding suggests a broader ersity of C. psittaci strains may be detected in horses and in association with reproductive loss, highlighting the need for an expansion of surveillance studies globally to understand the epidemiology of equine chlamydiosis and the associated zoonotic risk.
Publisher: Wiley
Date: 22-03-2021
DOI: 10.1111/AGE.13061
Publisher: SAGE Publications
Date: 03-2006
DOI: 10.1177/104063870601800209
Abstract: Improvements to restriction fragment length polymorphism (RFLP)-based genotyping assays currently used for detection of mutations responsible for bovine ferrochelatase and myophosphorylase deficiencies, and equine hyperkalemic periodic paralysis (HYPP) are described. Reports of sporadic inhibition of restriction enzyme activity suggest a critical factor in RFLP-based genotyping assays should be assurance that restriction enzymes perform to specification with every s le. The RFLP genotyping assays that use either a mismatched recognition sequence in one or both of the oligonucleotides, or incorporate a second native site within the PCR licon, provide the mechanism by which efficiency of restriction enzymes can be assessed with every s le. The outcome is confirmation of the activity of the discriminating enzyme regardless of genotype.
Publisher: Oxford University Press (OUP)
Date: 25-04-2019
DOI: 10.1093/JAS/SKZ144
Abstract: This study assessed cellular characteristics of longissimus lumborum (LL) and semitendinosus (ST) muscles in steers genetically selected for low (Low) or high (High) muscling using live muscle scoring, and High steers with 1 copy of the loss-of-function 821 del11 MSTN allele (HighHet). We hypothesized High and HighHet have altered muscle cellular characteristics and mechanisms influencing muscling compared with Low steers. Angus steers 25 mo old comprising 14 High, 19 Low, and 11 HighHet were backgrounded to 20 mo of age, grain finished for 150 d, and then slaughtered. Body and carcass weights did not differ due to muscling line (P = 0.46). Weight of LL was 16% greater (P = 0.004) and total protein in LL was 18% greater (P = 0.012) in HighHet than Low steers. ST weight in HighHet was 10% and 13% greater than in High and Low steers (P = 0.007), respectively, and of total ST protein 12% and 17% greater in HighHet than High or Low (P = 0.002). Cross-sectional area (CSA) of LL was greater in HighHet than in High and greater in High than in Low (85.0 vs. 77.0 vs. 70.4 cm2, P 0.001). Apparent number of myofibers and myofibers per unit CSA did not differ between the muscling lines in LL (P = 0.14) or ST (P = 0.47). Myofiber CSA was greater in the ST of Low than of High and HighHet for type 1 (36% and 31% respectively, P = 0.005) and 2A (22% and 25%, P 0.001). HighHet steers had greater area of glycolytic (type 2X) relative to more oxidative myofiber types within LL (P = 0.02 11% and 43% more than High and Low, respectively) and ST (P 0.001 27% and 75%). Concentration of RNA in LL was 13% and 10% greater (P = 0.005) in High than in Low and HighHet, respectively, and total amount of RNA in LL was 22% greater in High and 20% greater in HighHet than in Low (P 0.001). The LL of High steers had less protein to RNA (P = 0.03 57.4 vs. 65.6) and more RNA to DNA (P = 0.007 9.03 vs. 7.83) than Low. HighHet steers had 11% more DNA in ST than High (P = 0.04) and 19% more RNA in ST than Low (P = 0.012). The shift towards glycolytic myofibers was consistent with loadings in a principal component that explained 39% of the variation in LL and 38% in ST. Overall, these findings show that selection for increased muscling using live cattle muscle scoring, and 1 copy of the 821 del11 MSTN allele, results in more glycolytic muscle. They also suggest that increased muscling of the High compared with Low steers may be associated with increased translational capacity in the LL.
Publisher: Wiley
Date: 05-10-2018
DOI: 10.1111/ZPH.12391
Abstract: Psittacosis is a rare but potentially fatal zoonosis caused by Chlamydia psittaci, an organism that is typically associated with bird contact. However C. psittaci is capable of infecting other non-avian hosts, such as horses, sheep, cattle and goats. Stud staff and veterinarians have significant exposure to parturient animals and reproductive materials in their routine work. To investigate the zoonotic potential associated with the emergence of C. psittaci as an abortifacient agent in horses, we established a programme of joint human and animal surveillance in a sentinel horse-breeding region in Australia. This programme comprised cross-notification of equine cases to public health agencies, and active follow-up of known human contacts, including stud workers, foaling staff, veterinarians and laboratory staff. We identified no confirmed cases of acute psittacosis despite intensive surveillance and testing of heavily exposed contacts however, further work in the area is needed.
Publisher: Informa UK Limited
Date: 16-05-2018
Publisher: Elsevier BV
Date: 2006
Publisher: Elsevier BV
Date: 09-2015
DOI: 10.1016/J.VETPAR.2015.08.014
Abstract: Theileria orientalis is an emerging bovine pathogen in Australasia. PCR-based detection methods for this parasite are sensitive but relatively expensive, partly due to costs associated with DNA extraction. An inexpensive and efficient technique was developed for the extraction of T. orientalis DNA from blood based on hypotonic erythrocyte lysis and detergent-proteinase K treatment (DPK method). The DPK method compares favourably to a commercial extraction kit when paired with a T. orientalis multiplex qPCR.
Publisher: SAGE Publications
Date: 11-2005
DOI: 10.1177/104063870501700604
Abstract: Various forms of status spongiosus occur in neonatal cattle, the best characterized of which is due to mutations of the branched-chain alpha-keto acid dehydrogenase complex (BCKD), resulting in bovine maple syrup urine disease (MSUD, branched-chain ketoaciduria). A distinctive neurological syndrome was identified between 1998 and 2003 in 9 calves in a 250-cow stabilized Gelbvieh-Red Angus herd. Both sexes were affected (6 heifers, 3 bulls), with a low annual incidence (3 cases in 1998 no cases in 1999 2 cases in 2000 2 in 2001 1 in 2002 1 in 2003). Affected calves were born full-term, unable to stand, and had constant whole-body tremors when stimulated. Animals remained in lateral recumbency until death or euthanasia the longest survival time was 10 days postpartum. The principal histological change in 2 affected calves was diffuse, moderately severe bilaterally symmetrical status spongiosus with Alzheimer type II cells throughout the white matter of the brain. Myelin deficits were not evident and vacuoles were due to cleaved myelin sheaths. Neither recognized mutation of MSUD was identified in the E1a subunit of BCKD in 2 affected calves, 8 dams that gave birth to affected calves, a grand-dam of 3 affected calves, or a sire of 1 calf. Amino acid analysis of serum from 1 affected calf revealed normal concentrations of branched-chain amino acids, indicating that this disease is distinct from MSUD. The genetic and biochemical basis for the disorder, provisionally named congenital status spongiosus of Gelbvieh-cross cattle, is undetermined. The pattern of inheritance was not established.
Publisher: Oxford University Press (OUP)
Date: 09-2016
Publisher: Wiley
Date: 11-2019
DOI: 10.1111/AVJ.12877
Abstract: Cervicothoracic vertebral subluxation in sheep presents as a postural and locomotor disorder, and has been described in several breeds in Australia and overseas. Cervical myopathy may also be present in these cases. A New South Wales sheep producer reported a postural and locomotor disorder with a low prevalence in his Poll Merino stud flock, affecting neonate, weaner and adult sheep. Animals with postural abnormalities, variable degrees of ataxia and proprioceptive deficits involving both fore and hind limbs were described. Abnormalities of the cervicothoracic vertebral column were identified grossly during necropsy, with misalignment and consequent narrowing of the posterior cervical spinal canal. Lesions ranging from pallor (cellular degeneration) to white streaky lesions with pinpoint haemorrhage (necrosis) were identified in the cervicothoracic paravertebral musculature of affected animals. Boney abnormalities were further characterised by imaging studies. Pedigree analysis of the very extensive breeding and disease incident records available for this flock suggested that the disease was inherited. A similar case recognised in a separate New South Wales Poll Merino flock is also described. This report describes an entity of cervicothoracic vertebral subluxation in two Poll Merino sheep flocks, with cervical myopathy also identified in one, with preliminary evidence in the primary case that there is likely to be a hereditary basis. The two cases outlined in this report resemble the findings of several historical investigations into ovine flock postural disorders in Australia and beyond.
Publisher: Wiley
Date: 23-03-2013
DOI: 10.1111/J.1365-2052.2012.02354.X
Abstract: Double muscling is an inherited condition in cattle characterised by large increases in muscle mass. Mutations in the myostatin (MSTN) gene, responsible for double muscling, were targeted in this study to estimate the time since the most recent common ancestor (TMRCA) for Q204X (p.Gln204*), E226X (p.Glu226*), 821del11 (c.821del11), E291X (p.Glu291*), C313Y (p.Cys313Tyr) and the more phenotypically moderate F94L (p.Phe94Leu) mutation. Genetic variability was examined in eight regions upstream and downstream of the MSTN locus. The molecular distance of the homozygous region associated with each MSTN allele was used to estimate the TMRCA. Long homozygous segments were associated with the MSTN alleles (mostly > 2 Mb), compared to short segments (130 kb) for cattle wild type at the double muscling and F94L sites. Estimates of time indicated that each MSTN allele had a recent common ancestor (<400 years ago). The results from this study, and the increasing frequency of these MSTN alleles in some cattle breeds, demonstrate recent positive selection.
Publisher: SAGE Publications
Date: 06-08-2017
Abstract: Inherited forms of ichthyosis, or generalized scaling of the skin, have been reported in many animal species, including cattle, and are characterized by an autosomal recessive mode of inheritance. We investigated 2 calves affected with ichthyosis fetalis, a Polled Hereford and a Shorthorn. Both cases had hard white plaques on the skin consistent with excessive keratinization. This was confirmed by histopathology, which showed severe diffuse epidermal and follicular orthokeratotic hyperkeratosis. The known mutation (H1935R) in gene ABCA12, responsible for ichthyosis fetalis in Chianina cattle, was shown to be absent in both affected calves and their obligate heterozygous parents. These molecular findings indicate that allelic heterogeneity exists for this condition in cattle.
Publisher: American Society for Microbiology
Date: 15-04-2000
DOI: 10.1128/JB.182.8.2170-2178.2000
Abstract: Based on structural and functional properties, three groups of large staphylococcal multiresistance plasmids have been recognized, viz., the pSK1 family, pSK41-like conjugative plasmids, and β-lactamase–heavy-metal resistance plasmids. Here we describe an analysis of the replication functions of a representative of each of these plasmid groups. The replication initiation genes from the Staphylococcus aureus plasmids pSK1, pSK41, and pI9789::Tn 552 were found to be related to each other and to the Staphylococcus xylosus plasmid pSX267 and are also related to rep genes of several plasmids from other gram-positive genera. Nucleotide sequence similarity between pSK1 and pI9789::Tn 552 extended beyond their rep genes, encompassing upstream ergently transcribed genes, orf245 and orf256 , respectively. Our analyses revealed that genes encoding proteins related to the deduced orf245 product are variously represented, in several types of organization, on plasmids possessing six seemingly evolutionarily distinct types of replication initiation genes and including both theta-mode and rolling-circle replicons. Construction of minireplicons and subsequent functional analysis demonstrated that orf245 is required for the segregational stability of the pSK1 replicon. In contrast, no gene equivalent to orf245 is evident on the conjugative plasmid pSK41, and a minireplicon encoding only the pSK41 rep gene was found to exhibit a segregational stability approaching that of the parent plasmid. Significantly, the results described establish that many of the large multiresistance plasmids that have been identified in clinical staphylococci, which were formerly presumed to be unrelated, actually utilize an evolutionarily related theta-mode replication system.
Publisher: Elsevier BV
Date: 04-2002
Publisher: Wiley
Date: 30-09-2019
DOI: 10.1111/AGE.12856
Abstract: Two clinical forms of ichthyosis in cattle have been reported, ichthyosis fetalis and congenital ichthyosis. Ichthyosis poses animal welfare and economic issues and the more severe form, ichthyosis fetalis, is lethal. A Shorthorn calf with ichthyosis fetalis was investigated and a likely causal missense variant on chromosome 2 in the ABCA12 gene (NM_001191294.2:c.6776T>C) was identified by whole genome sequencing. Mutations in the ABCA12 gene are known to cause ichthyosis fetalis in cattle and Harlequin ichthyosis in humans. Sanger sequencing of the affected calf and the dam confirmed the variant was homozygous in the affected calf and heterozygous in the dam. Further genotyping of 130 Shorthorn animals from the same property revealed an estimated allele frequency of 3.8%. The presented findings enable genetic testing for breeding and diagnostics.
Publisher: Wiley
Date: 16-02-2016
DOI: 10.1111/AEN.12190
Publisher: Wiley
Date: 21-06-2020
DOI: 10.1111/AGE.12973
Publisher: Public Library of Science (PLoS)
Date: 24-09-2020
Publisher: Springer Science and Business Media LLC
Date: 15-09-2020
DOI: 10.1186/S12863-020-00913-8
Abstract: Brachygnathia, cardiomegaly and renal hypoplasia syndrome (BCRHS, OMIA 001595–9940 ) is a previously reported recessively inherited disorder in Australian Poll Merino/Merino sheep. Affected lambs are stillborn with various congenital defects as reflected in the name of the disease, as well as short stature, a short and broad cranium, a small thoracic cavity, thin ribs and brachysternum. The BCRHS phenotype shows similarity to certain human short stature syndromes, in particular the human 3M syndrome-2. Here we report the identification of a likely disease-causing variant and propose an ovine model for human 3M syndrome-2. Eight positional candidate genes were identified among the 39 genes in the approximately 1 Mb interval to which the disease was mapped previously. Obscurin like cytoskeletal adaptor 1 ( OBSL1 ) was selected as a strong positional candidate gene based on gene function and the resulting phenotypes observed in humans with mutations in this gene. Whole genome sequencing of an affected lamb (BCRHS3) identified a likely causal variant ENSOARG00000020239:g.220472248delC within OBSL1 . Sanger sequencing of seven affected, six obligate carrier, two phenotypically unaffected animals from the original flock and one unrelated control animal validated the variant. A genotyping assay was developed to genotype 583 animals from the original flock, giving an estimated allele frequency of 5%. The identification of a likely disease-causing variant resulting in a frameshift (p.(Val573Trpfs*119)) in the OBSL1 protein has enabled improved breeding management of the implicated flock. The opportunity for an ovine model for human 3M syndrome and ensuing therapeutic research is promising given the availability of carrier ram semen for BCRHS.
Publisher: CSIRO Publishing
Date: 2009
DOI: 10.1071/EA08206
Abstract: Two Australian beef cattle herds, in which selection for muscularity was a primary objective, were used in this study to identify bovine myostatin (MSTN) mutations associated with increased muscling, and to assess associations between genotype and performance, carcass and meat quality traits. One was a research herd (herd A) established from Angus × Hereford cows, and comprised a high and low muscle selection line. The other (herd B) was a commercial beef enterprise with cattle of Angus and Charolais origin. Sequencing of the MSTN coding region and flanking splice junctions in an initial s le of 34 animals from both herds identified the 821 del11 mutation as well as six other polymorphic sites. The nucleotide 374–50C T polymorphism in intron 1 was found to be in linkage disequilibrium with the 821 del11 mutation, with both variants confined to the high muscle selection line in herd A. No other variants were exclusive to either of the two herd A selection lines. The effect of the 821 del11 mutation was further investigated in a total of 803 cattle from both herds. A relatively high prevalence of 821 del11 heterozygotes (herd A 16% herd B 23%) was found and heterozygotes had significant advantages in eye muscle area and muscle score over their wildtype counterparts, and did not differ in meat quality. Retail beef yield from steers was higher for the 821 del11 heterozygotes from herd A (67.0 v. 63.5%) and herd B (71.8 v. 68.6%), relative to homozygous wildtype contemporaries, demonstrating the benefits of incorporating single null MSTN alleles into breeding programs.
Publisher: Hindawi Limited
Date: 19-01-2020
DOI: 10.1155/2020/9785861
Abstract: We describe three cases of osteoarticular infection (OAI) in young thoroughbred horses in which the causative organism was identified by MALDI-TOF as Kingella species . The pattern of OAI resembled that reported with Kingella infection in humans. Analysis by 16S rRNA PCR enabled construction of a phylogenetic tree that placed the isolates closer to Simonsiella and Alysiella species , rather than Kingella species . Average nucleotide identity (ANI) comparison between the new isolate and Kingella kingae and Alysiella crassa however revealed low probability that the new isolate belonged to either of these species. This preliminary analysis suggests the organism isolated is a previously unrecognised species.
No related grants have been discovered for Brendon O'Rourke.