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Peter J. Milburn - One of the best experts on this subject based on the ideXlab platform.
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venom from the platypus Ornithorhynchus Anatinus induces a calcium dependent current in cultured dorsal root ganglion cells
Journal of Neurophysiology, 2001Co-Authors: Greg M De Plater, Peter J. Milburn, Rosemary L MartinAbstract:The platypus (Ornithorhynchus Anatinus), a uniquely Australian species, is one of the few living venomous mammals. Although envenomation of humans by many vertebrate and invertebrate species result...
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the natriuretic peptide ovcnp 39 from platypus Ornithorhynchus Anatinus venom relaxes the isolated rat uterus and promotes oedema and mast cell histamine release
Toxicon, 1998Co-Authors: Greg M De Plater, Rosemary L Martin, Peter J. MilburnAbstract:Abstract In this study we characterise the ability of a C-type natriuretic peptide from platypus (Ornithorhynchus Anatinus) venom (ovCNP-39) to relax the rat uterus in vitro and we investigate the possibility that ovCNP-39 contributes to the acute effects of envenomation, which include oedema, pain and erythema. We have found that both ovCNP-39 and the endogenous C-type natriuretic peptide, CNP-22, produce oedema in the rat paw and release histamine from rat peritoneal mast cells. Two synthetic peptides, ovCNP-39(1–17) and ovCNP-39(18–39), corresponding to the N- and C-termini, respectively, are equipotent histamine releasers, suggesting that ovCNP-39 and other natriuretic peptides do not act through conventional natriuretic peptide receptors on mast cells.
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A C-type natriuretic peptide from the venom of the platypus (Ornithorhynchus Anatinus): Structure and pharmacology
Comparative biochemistry and physiology. Part C Pharmacology toxicology & endocrinology, 1998Co-Authors: Greg M De Plater, Rosemary L Martin, Peter J. MilburnAbstract:A peptide which relaxes rat uterine smooth muscle and exhibits homology with the mammalian C-type natriuretic peptide (CNP) has previously been identified in platypus (Ornithorhynchus Anatinus) venom from its partial N-terminal amino acid sequence. In this study we describe the purification, detailed structure, synthesis and pharmacological characteristics of this peptide, which has been designated ovCNP-39 (Ornithorhynchus venom C-type natriuretic peptide). Elucidation of the 39-residue amino acid sequence confirms the homology with mammalian CNPs. These peptides produce hypotension in vivo and relax smooth muscle in vitro, but are poorly characterised in terms of physiological function. ovCNP-39 is equipotent with human/rat/porcine CNP-22 in eliciting cyclic guanosine 5′-monophosphate (cGMP) elevation in cultured vascular smooth muscle cells, suggesting that, like CNP, it acts through the ANPB natriuretic peptide receptor subtype. The direct elevation of cGMP in vascular smooth muscle by ovCNP-39 may underlie the vasodilatory effects of platypus envenomation.
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a pharmacological and biochemical investigation of the venom from the platypus Ornithorhynchus Anatinus
Toxicon, 1995Co-Authors: Greg M De Plater, Rosemary L Martin, Peter J. MilburnAbstract:In this study several activities of the venom of Ornithorhynchus Anatinus have been investigated. Whole venom induced local oedema after subplantar injection and produced relaxation of the rat uterus in vitro. The relaxant activity was partially purified by gel permeation HPLC and subsequent analyses by SDS-PAGE revealed that this activity was associated with a 4200 mol. wt peptide. The N-terminal partial sequence of this peptide exhibited substantial identity with human and porcine C-type natriuretic peptide (CNP). Three other major proteins isolated from the venom had mol. wts of 140,000, 55,000 and 16,000. None was found to have any sequence homology with proteins listed in the SwissProt database. The 140,000 mol. wt protein exhibited hyaluronidase activity but the nature of the 55,000 and 16,000 mol. wt proteins remains to be determined. Platypus venom also exhibits protease activity, although the concentration of proteolytic enzymes was too low to be visualised by SDS-PAGE using Coomassie staining.
T.r. Grant - One of the best experts on this subject based on the ideXlab platform.
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effect of flow on platypus Ornithorhynchus Anatinus reproduction and related population processes in the upper shoalhaven river
Australian Journal of Zoology, 2017Co-Authors: M Serena, T.r. GrantAbstract:The platypus (Ornithorhynchus Anatinus) occupies a wide range of aquatic habitats, feeding mainly on benthic macroinvertebrates. In this study, we investigated how flow affects platypus reproduction in the unregulated upper Shoalhaven River in rural New South Wales. In a mainly dry period, the population occurred at relatively high density (12.4 animals km–1) and was strongly female-biased (84% of resident animals); mean annual loss and recruitment of resident females were respectively estimated to be 12% and 14%. Percentage lactation was 17–71% (n = 23 years), and annual reproductive success (defined as the mean number of juveniles captured per adult/subadult female from February to April) varied from 0 to 1.5 juveniles female–1 (n = 21 years). A significant positive linear relationship was evident between percentage lactation and antecedent discharge in the five months before breeding (March–July) and a positive curvilinear relationship was evident between percentage lactation and mean litter size. Conversely, reproductive success was compromised by high poststorm discharge in the period when juveniles are confined to a nesting burrow, especially from late November to early January. The relationships identified in our study between flow and reproduction also appear to apply to platypus populations occupying urban streams in Victoria, suggesting that they may be widely relevant to this species.
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life history and dynamics of a platypus Ornithorhynchus Anatinus population four decades of mark recapture surveys
Scientific Reports, 2015Co-Authors: Gilad Bino, T.r. Grant, Richard T KingsfordAbstract:Knowledge of the life-history and population dynamics of Australia’s iconic and evolutionarily distinct platypus (Ornithorhynchus Anatinus) remains poor. We marked-recaptured 812 unique platypuses (total 1,622 captures), over four decades (1973–2014) in the Shoalhaven River, Australia. Strong sex-age differences were observed in life-history, including morphology and longevity. Apparent survival of adult females (Φ = 0.76) were higher than adult males (Φ = 0.57), as in juveniles: females Φ = 0.27, males Φ = 0.13. Females were highly likely to remain in the same pool (adult: P = 0.85, juvenile: P = 0.88), while residency rates were lower for males (adult: P = 0.74, juvenile: P = 0.46). We combined survival, movement and life-histories to develop population viability models and test the impact of a range of life-history parameters. While using estimated apparent survival produced unviable populations (mean population growth rate r = −0.23, extinction within 20 years), considering residency rates to adjust survival estimates, indicated more stable populations (r = 0.004, p = 0.04 of 100-year extinction). Further sensitivity analyses highlighted adult female survival and overall success of dispersal as most affecting viability. Findings provide robust life-history and viability estimates for a difficult study species. These could support developing large-scale population dynamics models required to underpin a much needed national risk assessment for the platypus, already declining in parts of its current distribution.
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regional population structuring and conservation units in the platypus Ornithorhynchus Anatinus
Australian Journal of Zoology, 2013Co-Authors: T.r. Grant, Stephen H Kolomyjec, Christopher N Johnson, David BlairAbstract:The platypus (Ornithorhynchus Anatinus) has a wide distribution in Australia, encompassing the southern island of Tasmania and a broad latitudinal range of the mainland from the temperate south to the tropical north. We used 12 microsatellite markers from 235 individuals sampled from 13 river systems to examine patterns of genetic differentiation and gene flow throughout the species’ range. Using a Bayesian approach we identified three large-scale groupings that correspond closely to geographically distinct regions of the species’ distribution: the tropical northern mainland, the subtropical and temperate southern mainland, and Tasmania. Six additional clusters were found within the regional groups, three in the northern, two in the southern mainland regions, and the last in Tasmania. These clusters coincided with major river drainages. Genetic differentiation was generally high, with pairwise Fst values ranging from 0.065 to 0.368 for regions and 0.037 to 0.479 for clusters. We found no evidence of contemporary gene flow among the three clusters in the north, but some migration may occur between the larger clusters in the south. Due to the high genetic structuring and lack of gene flow between these three regional populations of the platypus we recommend their treatment as evolutionarily significant units (ESUs) within the platypus species. We have also detailed several smaller management units (MUs) existing within our study area based on subregional clusters and geographically significant features.
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Dispersal patterns and population structuring among platypuses, Ornithorhynchus Anatinus, throughout south-eastern Australia
Conservation Genetics, 2013Co-Authors: E. M. Furlan, T.r. Grant, Kathrine A Handasyde, J. Griffiths, N. Gust, B. Gruber, A. R. WeeksAbstract:Dispersal patterns can have a major impact on the dynamics and viability of populations, and understanding these patterns is crucial to the conservation and management of a species. In this study, patterns of sex-biased dispersal and waterway/overland dispersal are investigated in the endemic Australian platypus, Ornithorhynchus Anatinus , a semi-aquatic monotreme. Analyses of over 750 individuals from south-eastern Australia at 13 microsatellite loci and two mitochondrial genes, cytochrome b and cytochrome oxidase subunit II, provide genetic insight into dispersal patterns. For the first time, platypuses of western Victoria are shown to be genetically distinct from other populations of the mainland. Despite distinct morphological differentiation either side of the Great Dividing Range, populations remain genetically similar between coastal and inland areas suggesting gene flow is likely to occur across these ranges. Landscape genetic analyses indicate variability in dispersal patterns between Victorian and Tasmanian platypuses with a greater avoidance of overland travel indicated in Victoria compared to Tasmania. Females appear to remain within their natal area or return to breed, maintaining greater genetic structure in maternally inherited mitochondrial DNA in comparison to nuclear DNA and sharing genetic similarity within a short river distance (i.e. ≤1.4 km). The results of this study provide a valuable spatial framework for the management of wild platypus populations within south-eastern Australia and a baseline for future monitoring of populations that are likely to be impacted by environmental and anthropogenic change.
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population genetics of the platypus Ornithorhynchus Anatinus a fine scale look at adjacent river systems
Australian Journal of Zoology, 2009Co-Authors: Stephen H Kolomyjec, T.r. Grant, David Blair, Josephine Y T Chong, Jaime Gongora, Christopher N Johnson, C J MoranAbstract:Population genetics is a powerful tool to increase the understanding of animals that may otherwise be difficult to study, such as the platypus (Ornithorhynchus Anatinus). Focusing on two adjacent river systems in New South Wales, we used 12 polymorphic microsatellite loci to investigate the population dynamics of the platypus.We found that individual river systems acted as discrete population units. Evidence of migration, presumably overland, between systems explains how these units remain connected. This establishes an isolation-by-distance pattern that maintains species continuity across most of the mainland distribution. This improved understanding of population structure will be a valuable contribution to designing accurate management plans for the long-term conservation of this unique Australian animal.
B L Munday - One of the best experts on this subject based on the ideXlab platform.
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accumulation of persistent organic pollutants in tasmanian platypus Ornithorhynchus Anatinus
Environmental Pollution, 2002Co-Authors: B L Munday, Niall Stewart, Anders SodergrenAbstract:Tailfat samples were collected from 56 platypuses, 38 male and 18 female in Tasmania. No statistically significant, nor apparent, differences between the sexes were found for tailfat lipid levels and DDT and its metabolites. Lindane and PCB concentrations in tailfat lipid. Apparently--but not statistically--significantly different levels of DDT and its metabolites. Lindane and PCB concentrations were found in animals from different geographic regions of the State. Higher concentrations of DDT and its metabolites and Lindane were related to the intensity of agricultural activity and elevated PCB levels were mainly found in animals from zones with industrial and hydroelectric developments.
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evidence for an early appearance of modern post switch immunoglobulin isotypes in mammalian evolution ii cloning of ige igg1 and igg2 from a monotreme the duck billed platypus Ornithorhynchus Anatinus
European Journal of Immunology, 2002Co-Authors: Molly Vernersson, Maria Aveskogh, B L Munday, Lars HellmanAbstract:To trace the emergence of the modern post-switch immunoglobulin (Ig) isotypes in vertebrate evolution we have studied Ig expression in mammals distantly related to eutherians. We here present an analysis of the Ig expression in an egg-laying mammal, a monotreme, the duck-billed platypus (Ornithorhynchus Anatinus). Fragments of platypus IgG and IgE cDNA were obtained by a PCR-based screening using degenerate primers. The fragments obtained were used as probes to isolate full-length cDNA clones of three platypus post-switch isotypes, IgG1, IgG2, and IgE. Comparative amino acid sequence analysis against IgY, IgE and IgG from various animal species revealed that platypus IgE and IgG form branches that are clearly separated from those of their eutherian (placental) counterparts. However, the platypus IgE and IgG still conform to the general structure displayed by the respective Ig isotypes of eutherian and marsupial mammals. According to our findings, all of the major evolutionary changes in the expression array and basic Ig structure that have occurred since the evolutionary separation of mammals from the early reptile lineages, occurred prior to the separation of monotremes from marsupial and placental mammals. Hence, our results indicate that the modern post-switch isotypes appeared very early in the mammalian lineage, possibly already 310-330 million years ago.
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heavy chain v region diversity in the duck billed platypus Ornithorhynchus Anatinus long and highly variable complementarity determining region 3 compensates for limited germline diversity
Journal of Immunology, 2002Co-Authors: Jeannette Johansson, Maria Aveskogh, B L Munday, Lars HellmanAbstract:In this work, to study the emergence of the H chain V region repertoire during mammalian evolution, we present an analysis of 25 independent H chain V regions from a monotreme, the Australian duck-billed platypus, Ornithorhynchus Anatinus. All the sequences analyzed were found to form a single branch within the clan III of mammalian V region sequences in a distance tree. However, compared with a classical V gene family this branch was more diversified in sequence. Sequence analysis indicates that the apparent lack of diversity in germline V segments is well compensated for by relatively long and highly diversified D and N nucleotides. In addition, extensive sequence variation was observed in the framework region 3. Furthermore, at least five and possibly seven different J segments seem to be actively used in recombination. Interestingly, internal cysteine bridges in the complementarity-determining region (CDR)3 loop, or between the CDR2 and CDR3 loops, are found in ∼36% of the platypus VH sequences. Such cysteine bridges have also been observed in cow, camel, and shark. Internal cysteine bridges may play a role in stabilizing long and diversified CDR3 and thereby have a role in increasing the affinity of the Ab-Ag interaction.
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isolation of mucor circinelloides from a case of ulcerative mycosis of platypus Ornithorhynchus Anatinus and a comparison of the response of mucor circinelloides and mucor amphibiorum to different culture temperatures
Medical Mycology, 1999Co-Authors: Niall Stewart, B L Munday, T M HawkesfordAbstract:The fungus Mucor circinelloides was isolated from a platypus (Ornithorhynchus Anatinus) suffering from ulcerative mycosis. On horse blood agar at 20, 25 and 30°C, the fungus formed sphaerule-like bodies, a morphology previously associated with Mucor amphibiorum, the species thought to be responsible for the disease in platypus. A biopsy taken from the ulcer was fixed, cut and stained. The sections were compared with sections taken from other platypuses suffering from ulcerative mycosis, and from which M. amphibiorum had been isolated. There were no discernible differences between the sphaerule-like bodies found in any of the sections. The presence of sphaerule-like bodies in tissues of ulcerated animals can, therefore, probably no longer be relied upon as a definitive method for the diagnosis of M. amphibiorum infection. It is possible that M. circinelloides is either a primary or a secondary pathogen of platypuses, and further work is required to resolve this point. The isolate of M. circinelloides grew ...
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disease conditions and subclinical infections of the platypus Ornithorhynchus Anatinus
Philosophical Transactions of the Royal Society B, 1998Co-Authors: B L Munday, R J Whittington, N J StewartAbstract:Before the arrival of European settlers in Australia, the platypus, Ornithorhynchus Anatinus, probably suffered from little disease. Among other things, European settlement has involved substantial environmental perturbation, introduction of large predators, introduction of motor vehicles and translocation of potential pathogens. As a result, platypuses are now killed by motor vehicles, dogs, foxes and discarded plastic litter. Information programmes targeting appropriate segments of the public would help reduce these unnecessary deaths. The enigmatic disease, ulcerative mycosis, caused by Mucor amphibiorum, has been the subject of scientific investigation in Tasmania for the past 15 years. The apparent recent acceleration in its spread has sounded a warning and more intensive investigation is warranted. The possibility that this pathogen has been translocated from subtropical to temperate Tasmania, Australia, with green free frogs in banana shipments further emphasizes the role of humans in threatening the welfare of the platypus. Recommendations are made in relation to appropriate measures that could be taken to ameliorate disease and trauma in this species.
Katherine Belov - One of the best experts on this subject based on the ideXlab platform.
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Phylogenetic tree comparing Rhinella marina MHC class I to other vertebrates.
2014Co-Authors: Mette Lillie, Richard Shine, Katherine BelovAbstract:Maximum likelihood phylogenetic tree using General Time Reversible model of nucleotide substitution with invariant sites (rooted on midpoint) of MHC class I in cane toad, Rhinella marina, African clawed frog, Xenopus laevis, northern leopard frog, Rana pipiens, Atlantic salmon, Salmo salar, whitespotted bamboo shark, Chiloscyllium plagiosum, nurse shark, Ginglymostoma cirratum, chicken, Gallus gallus, platypus, Ornithorhynchus Anatinus, gray short-tailed opossum, Monodelphis domestica, red-necked wallaby, Macropus rufogriseus, common chimpanzee, Pan troglodytes, and human, Homo sapiens. Sequence titles include Genbank accessions.
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diversity at the major histocompatibility complex class ii in the platypus Ornithorhynchus Anatinus
Journal of Heredity, 2012Co-Authors: Mette Lillie, Rachael E. Woodward, Mark D. B. Eldridge, Claire Sanderson, Katherine BelovAbstract:The platypus (Ornithorhynchus Anatinus) is the sole survivor of a previously widely distributed and diverse lineage of ornithorhynchid monotremes. Its dependence on healthy water systems imposes an inherent sensitivity to habitat degradation and climate change. Here, we compare genetic diversity at the major histocompatibility complex (MHC) Class II-DZB gene and 3 MHC-associated microsatellite markers with diversity at 6 neutral microsatellite markers in 70 platypuses from across their range, including the mainland of Australia and the isolated populations of Tasmania, King Island, and Kangaroo Island. Overall, high DZB diversity was observed in the platypus, with 57 DZB β1 alleles characterized. Significant positive selection was detected within the DZB peptide-binding region, promoting variation in this domain. Low levels of genetic diversity were detected at all markers in the 2 island populations, King Island (endemic) and Kangaroo Island (introduced), with the King Island platypuses monomorphic at the DZB locus. Loss of MHC diversity on King Island is of concern, as the population may have compromised immunological fitness and reduced ability to resist changing environmental conditions.
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Ornithorhynchus Anatinus platypus links the evolution of immunoglobulin genes in eutherian mammals and nonmammalian tetrapods
Journal of Immunology, 2009Co-Authors: Yaofeng Zhao, Camilla M Whittington, Lars Hellman, Huiting Cui, Zhiguo Wei, Xiaofeng Zhang, Ziding Zhang, Liming Ren, Yaping Zhang, Katherine BelovAbstract:The evolutionary origins of mammalian immunoglobulin H chain isotypes (IgM, IgD, IgG, IgE, and IgA) are still incompletely understood as these isotypes differ considerably in structure and number from their counterparts in nonmammalian tetrapods. We report in this study that the platypus (Ornithorhynchus Anatinus) Ig H chain constant region gene locus contains eight Ig encoding genes, which are arranged in an mu-delta-omicron-gamma2-gamma1-alpha1-epsilon-alpha2 order, spanning a total of approximately 200 kb DNA, encoding six distinct isotypes. The omicron (omicron for Ornithorhynchus) gene encodes a novel Ig H chain isotype that consists of four constant region domains and a hinge, and is structurally different from any of the five known mammalian Ig classes. This gene is phylogenetically related to upsilon (epsilon) and gamma, and thus appears to be a structural intermediate between these two genes. The platypus delta gene encodes ten heavy chain constant region domains, lacks a hinge region and is similar to IgD in amphibians and fish, but strikingly different from that in eutherian mammals. The platypus Ig H chain isotype repertoire thus shows a unique combination of genes that share similarity both to those of nonmammalian tetrapods and eutherian animals and demonstrates how phylogenetically informative species can be used to reconstruct the evolutionary history of functionally important genes.
Greg M De Plater - One of the best experts on this subject based on the ideXlab platform.
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venom from the platypus Ornithorhynchus Anatinus induces a calcium dependent current in cultured dorsal root ganglion cells
Journal of Neurophysiology, 2001Co-Authors: Greg M De Plater, Peter J. Milburn, Rosemary L MartinAbstract:The platypus (Ornithorhynchus Anatinus), a uniquely Australian species, is one of the few living venomous mammals. Although envenomation of humans by many vertebrate and invertebrate species result...
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the natriuretic peptide ovcnp 39 from platypus Ornithorhynchus Anatinus venom relaxes the isolated rat uterus and promotes oedema and mast cell histamine release
Toxicon, 1998Co-Authors: Greg M De Plater, Rosemary L Martin, Peter J. MilburnAbstract:Abstract In this study we characterise the ability of a C-type natriuretic peptide from platypus (Ornithorhynchus Anatinus) venom (ovCNP-39) to relax the rat uterus in vitro and we investigate the possibility that ovCNP-39 contributes to the acute effects of envenomation, which include oedema, pain and erythema. We have found that both ovCNP-39 and the endogenous C-type natriuretic peptide, CNP-22, produce oedema in the rat paw and release histamine from rat peritoneal mast cells. Two synthetic peptides, ovCNP-39(1–17) and ovCNP-39(18–39), corresponding to the N- and C-termini, respectively, are equipotent histamine releasers, suggesting that ovCNP-39 and other natriuretic peptides do not act through conventional natriuretic peptide receptors on mast cells.
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A C-type natriuretic peptide from the venom of the platypus (Ornithorhynchus Anatinus): Structure and pharmacology
Comparative biochemistry and physiology. Part C Pharmacology toxicology & endocrinology, 1998Co-Authors: Greg M De Plater, Rosemary L Martin, Peter J. MilburnAbstract:A peptide which relaxes rat uterine smooth muscle and exhibits homology with the mammalian C-type natriuretic peptide (CNP) has previously been identified in platypus (Ornithorhynchus Anatinus) venom from its partial N-terminal amino acid sequence. In this study we describe the purification, detailed structure, synthesis and pharmacological characteristics of this peptide, which has been designated ovCNP-39 (Ornithorhynchus venom C-type natriuretic peptide). Elucidation of the 39-residue amino acid sequence confirms the homology with mammalian CNPs. These peptides produce hypotension in vivo and relax smooth muscle in vitro, but are poorly characterised in terms of physiological function. ovCNP-39 is equipotent with human/rat/porcine CNP-22 in eliciting cyclic guanosine 5′-monophosphate (cGMP) elevation in cultured vascular smooth muscle cells, suggesting that, like CNP, it acts through the ANPB natriuretic peptide receptor subtype. The direct elevation of cGMP in vascular smooth muscle by ovCNP-39 may underlie the vasodilatory effects of platypus envenomation.
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a pharmacological and biochemical investigation of the venom from the platypus Ornithorhynchus Anatinus
Toxicon, 1995Co-Authors: Greg M De Plater, Rosemary L Martin, Peter J. MilburnAbstract:In this study several activities of the venom of Ornithorhynchus Anatinus have been investigated. Whole venom induced local oedema after subplantar injection and produced relaxation of the rat uterus in vitro. The relaxant activity was partially purified by gel permeation HPLC and subsequent analyses by SDS-PAGE revealed that this activity was associated with a 4200 mol. wt peptide. The N-terminal partial sequence of this peptide exhibited substantial identity with human and porcine C-type natriuretic peptide (CNP). Three other major proteins isolated from the venom had mol. wts of 140,000, 55,000 and 16,000. None was found to have any sequence homology with proteins listed in the SwissProt database. The 140,000 mol. wt protein exhibited hyaluronidase activity but the nature of the 55,000 and 16,000 mol. wt proteins remains to be determined. Platypus venom also exhibits protease activity, although the concentration of proteolytic enzymes was too low to be visualised by SDS-PAGE using Coomassie staining.
