22 research outputs found

    Slow lorises use venom as a weapon in intraspecific competition

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    Animals have evolved an array of spectacular weapons, including antlers, forceps, proboscises, stingers, tusks and horns [ 1 ]. Weapons can be present in males and females of species needing to defend critical limiting resources, including food (rhinoceros beetles, Trypoxylus) and territories (fang blennies, Meiacanthus) [ 1 , 2 , 3 ]. Chemicals, including sprays, ointments and injected venoms, are another defence system used by animals. As with morphological weapons, venom can serve multiple purposes, including to facilitate feeding, in predation, and in defence when attacked [ 4 ]. Although rare, several taxa use venom for agonistic intraspecific competition (e.g. ghost shrimp, Caprella spp.; sea anemones, Actinia equina; cone snails, Conidae; male platypus, Ornithorhynchus anatinus) [ 4 , 5 , 6 ]. Another group of venomous mammals are the nocturnal slow lorises ( Nycticebus) [ 7 ]. Slow loris bites often result in dramatic diagnostic wounds characterised by necrotic gashes to the head and extremities. Although these bites are the major cause of death of lorises in captivity, the function of this aggressive behaviour has never been studied in the wild [ 7 ]. Here, through an 8-year study of wounding patterns, territorial behaviour, and agonistic encounters of a wild population of Javan slow lorises ( Nycticebus javanicus), we provide strong evidence that venom is used differentially by both sexes to defend territories and mates

    The toxicological intersection between allergen and toxin: A structural comparison of the cat dander allergenic protein Fel d1 and the slow loris brachial gland secretion protein

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    Slow lorises are enigmatic animal that represent the only venomous primate lineage. Their defensive secretions have received little attention. In this study we determined the full length sequence of the protein secreted by their unique brachial glands. The full length sequences displayed homology to the main allergenic protein present in cat dander. We thus compared the molecular features of the slow loris brachial gland protein and the cat dander allergen protein, showing remarkable similarities between them. Thus we postulate that allergenic proteins play a role in the slow loris defensive arsenal. These results shed light on these neglected, novel animals

    Multi-locus phylogeny and species delimitation of Australo-Papuan blacksnakes (Pseudechis Wagler, 1830: Elapidae: Serpentes)

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    Genetic analyses of Australasian organisms have resulted in the identification of extensive cryptic diversity across the continent. The venomous elapid snakes are among the best-studied organismal groups in this region, but many knowledge gaps persist: for instance, despite their iconic status, the species-level diversity among Australo-Papuan blacksnakes (Pseudechis) has remained poorly understood due to the existence of a group of cryptic species within the P. australis species complex, collectively termed ‘‘pygmy mulga snakes”. Using two mitochondrial and three nuclear loci we assess species boundaries within the genus using Bayesian species delimitation methods and reconstruct their phylogenetic history using multispecies coalescent approaches. Our analyses support the recognition of 10 species, including all of the currently described pygmy mulga snakes and one undescribed species from the Northern Territory of Australia. Phylogenetic relationships within the genus are broadly consistent with previous work, with the recognition of three major groups, the viviparous red-bellied black snake P. porphyriacus forming the sister species to two clades consisting of ovoviviparous specie

    Vintage venoms: proteomic and pharmacological stability of snake venoms stored for up to eight decades

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    For over a century, venom samples from wild snakes have been collected and stored around the world. However, the quality of storage conditions for "vintage" venoms has rarely been assessed. The goal of this study was to determine whether such historical venom samples are still biochemically and pharmacologically viable for research purposes, or if new sample efforts are needed. In total, 52 samples spanning 5 genera and 13 species with regional variants of some species (e.g., 14 different populations of Notechis scutatus) were analysed by a combined proteomic and pharmacological approach to determine protein structural stability and bioactivity. When venoms were not exposed to air during storage, the proteomic results were virtually indistinguishable from that of fresh venom and bioactivity was equivalent or only slightly reduced. By contrast, a sample of Acanthophis antarcticus venom that was exposed to air (due to a loss of integrity of the rubber stopper) suffered significant degradation as evidenced by the proteomics profile. Interestingly, the neurotoxicity of this sample was nearly the same as fresh venom, indicating that degradation may have occurred in the free N- or C-terminus chains of the proteins, rather than at the tips of loops where the functional residues are located. These results suggest that these and other vintage venom collections may be of continuing value in toxin research. This is particularly important as many snake species worldwide are declining due to habitat destruction or modification. For some venoms (such as N. scutatus from Babel Island, Flinders Island, King Island and St. Francis Island) these were the first analyses ever conducted and these vintage samples may represent the only venom ever collected from these unique island forms of tiger snakes. Such vintage venoms may therefore represent the last remaining stocks of some local populations and thus are precious resources. These venoms also have significant historical value as the Oxyuranus venoms analysed include samples from the first coastal taipan (Oxyuranus scutellatus) collected for antivenom production (the snake that killed the collector Kevin Budden), as well as samples from the first Oxyuranus microlepidotus specimen collected after the species' rediscovery in 1976. These results demonstrate that with proper storage techniques, venom samples can retain structural and pharmacological stability. This article is part of a Special Issue entitled: Proteomics of non-model organisms. Biological significance: ‱These results show that with proper storage venoms are useful for decades.‱These results have direct implications for the use of rare venoms

    A biochemical and pharmacological analysis of novel natriuretic peptides from the venoms of Australian elapid snakes

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    Toxins: State of Journal Report, 2016

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    In the “Message from the Editor-in-Chief” posted on the Toxins website (see www.mdpi.com/journal/toxins/toxins-flyer.pdf), we wrote: “The editorial board and staff of Toxins are dedicated to providing a timely, peer-reviewed outlet for exciting, innovative primary research articles and concise, informative reviews from investigators in the myriad of disciplines contributing to our knowledge on toxins. [...

    The good, the bad and the ugly: Australian snake taxonomists and a history of the taxonomy of Australia's venomous snakes

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    The Australian snake fauna is unique in harbouring more venomous species than non-venomous ones. Although taxonomic research on the elapid snakes of Australia goes back to the late 18th century, in stark contrast to other developed regions of the world (e.g. the continental USA), Australian snake taxonomy is very much in its infancy. Despite this, or perhaps because of this, the taxonomy of Australian snakes has been extraordinarily controversial, and many of the taxonomists involved correspondingly colourful. In this review, we explore the sometimes-tortured history of the taxonomic exploration of the venomous snake fauna of Australia, looking at some of the more colourful and notable contributors and highlighting systematic pitfalls that persist even today

    Genetic identification of Southern Ocean octopod samples using mtCOI

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    East Antarctic octopods were identified by sequencing mtCOI and using four analytical approaches: Neighbor-joining by Kimura-2-Parameter-based distances, character-based, BLAST, and Bayesian Inference of Phylogeny. Although the distance-based analytical approaches identified a high proportion of the sequences (99.5% to genus and 88.1% to species level), these results are undermined by the absence of a clear gap between intra-and interspecific variation. The character-based approach gave highly conflicting results compared to the distance-based methods and failed to identify apomorphic characters for many of the species. While a DNA independent approach is necessary for validation of the method comparisons, crude morphological observations give early support to the distance-based results and indicate extensive range expansions of several species compared to previous studies. Furthermore, the use of distance-based phylogenetic methods nevertheless group specimens into plausible species clades that are highly useful in non-taxonomical or non-systematic studies. (C) 2010 Academie des sciences. Published by Elsevier Masson SAS. All rights reserved

    Snakes across the Strait: trans-Torresian phylogeographic relationships in three genera of Australasian snakes (Serpentes: Elapidae: Acanthophis, Oxyuranus, and Pseudechis)

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    We analyze the phylogeny of three genera of Australasian elapid snakes (Acanthophis—death adders; Oxyuranus—taipans; Pseudechis—blacksnakes), using parsimony, maximum likelihood, and Bayesian analysis of sequences of the mitochondrial cytochrome b and ND4 genes. In Acanthophis and Pseudechis, we find evidence of multiple trans-Torresian sister-group relationships. Analyses of the timing of cladogenic events suggest crossings of the Torres Strait on several occasions between the late Miocene and the Pleistocene. These results support a hypothesis of repeated land connections between Australia and New Guinea in the late Cenozoic. Additionally, our results reveal undocumented genetic diversity in Acanthophis and Pseudechis, supporting the existence of more species than previously believed, and provide a phylogenetic framework for a reinterpretation of the systematics of these genera. In contrast, our Oxyuranus scutellatus samples from Queensland and two localities in New Guinea share a single haplotype, suggesting very recent (late Pleistocene) genetic exchange between New Guinean and Australian populations

    Structure-activity relationship of chlorotoxin-like peptides

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    Animal venom (e.g., scorpion) is a rich source of various protein and peptide toxins with diverse physio-/pharmaco-logical activities, which generally exert their action via target-specific modulation of different ion channel functions. Scorpion venoms are among the most widely-known source of peptidyl neurotoxins used for callipering different ion channels, such as; Na+, K+, Ca+, Cl-, etc. A new peptide of the chlorotoxin family (i.e., Bs-Tx7) has been isolated, sequenced and synthesized from scorpion Buthus sindicus (family Buthidae) venom. This peptide demonstrates 66% with chlorotoxin (ClTx) and 82% with CFTR channel inhibitor (GaTx1) sequence identities reported from Leiurus quinquestriatus hebraeus venom. The toxin has a molecular mass of 3821 Da and possesses four intra-chain disulphide bonds. Amino acid sequence analysis of Bs-Tx7 revealed the presence of a scissile peptide bond (i.e., Gly-Ile) for human MMP2, whose activity is increased in the case of tumour malignancy. The effect of hMMP2 on Bs-Tx7, or vice versa, observed using the FRET peptide substrate with methoxycoumarin (Mca)/dinitrophenyl (Dnp) as fluorophore/quencher, designed and synthesized to obtain the lowest Km value for this substrate, showed approximately a 60% increase in the activity of hMMP2 upon incubation of Bs-Tx7 with the enzyme at a micromolar concentration (4 mu M), indicating the importance of this toxin in diseases associated with decreased MMP2 activity
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