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Sample records for snake toxins binding

  1. Toxin synergism in snake venoms

    DEFF Research Database (Denmark)

    Laustsen, Andreas Hougaard

    2016-01-01

    Synergism between venom toxins exists for a range of snake species. Synergism can be derived from both intermolecular interactions and supramolecular interactions between venom components, and can be the result of toxins targeting the same protein, biochemical pathway or physiological process. Few...... simple systematic tools and methods for determining the presence of synergism exist, but include co-administration of venom components and assessment of Accumulated Toxicity Scores. A better understanding of how to investigate synergism in snake venoms may help unravel strategies for developing novel...

  2. Snake venom toxins: toxicity and medicinal applications.

    Science.gov (United States)

    Chan, Yau Sang; Cheung, Randy Chi Fai; Xia, Lixin; Wong, Jack Ho; Ng, Tzi Bun; Chan, Wai Yee

    2016-07-01

    Snake venoms are complex mixtures of small molecules and peptides/proteins, and most of them display certain kinds of bioactivities. They include neurotoxic, cytotoxic, cardiotoxic, myotoxic, and many different enzymatic activities. Snake envenomation is a significant health issue as millions of snakebites are reported annually. A large number of people are injured and die due to snake venom poisoning. However, several fatal snake venom toxins have found potential uses as diagnostic tools, therapeutic agent, or drug leads. In this review, different non-enzymatically active snake venom toxins which have potential therapeutic properties such as antitumor, antimicrobial, anticoagulating, and analgesic activities will be discussed.

  3. High-throughput epitope profiling of snake venom toxins

    DEFF Research Database (Denmark)

    Engmark, Mikael; Andersen, Mikael Rørdam; Laustsen, Andreas Hougaard

    Insight into the molecular details of polyclonal antivenom antibody specificity is a prerequisite for accurate prediction of cross-reactivity and can provide a basis for design of novel antivenoms. In this work, a highthroughput approach was applied to characterize linear elements in epitopes in ...... toxins from four African mamba and three neurotoxic cobra snakes obtained from public databases....

  4. Snake Venom: From Deadly Toxins to Life-saving Therapeutics.

    Science.gov (United States)

    Waheed, Humera; Moin, Syed F; Choudhary, M I

    2017-01-01

    Snakes are fascinating creatures and have been residents of this planet well before ancient humans dwelled the earth. Venomous snakes have been a figure of fear, and cause notable mortality throughout the world. The venom constitutes families of proteins and peptides with various isoforms that make it a cocktail of diverse molecules. These biomolecules are responsible for the disturbance in fundamental physiological systems of the envenomed victim, leading to morbidity which can lead to death if left untreated. Researchers have turned these life-threatening toxins into life-saving therapeutics via technological advancements. Since the development of captopril, the first drug that was derived from bradykininpotentiating peptide of Bothrops jararaca, to the disintegrins that have potent activity against certain types of cancers, snake venom components have shown great potential for the development of lead compounds for new drugs. There is a continuous development of new drugs from snake venom for coagulopathy and hemostasis to anti-cancer agents. In this review, we have focused on different snake venom proteins / peptides derived drugs that are in clinical use or in developmental stages till to date. Also, some commonly used snake venom derived diagnostic tools along with the recent updates in this exciting field are discussed. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  5. Venom Down Under: Dynamic Evolution of Australian Elapid Snake Toxins

    Science.gov (United States)

    Jackson, Timothy N. W.; Sunagar, Kartik; Undheim, Eivind A. B.; Koludarov, Ivan; Chan, Angelo H. C.; Sanders, Kate; Ali, Syed A.; Hendrikx, Iwan; Dunstan, Nathan; Fry, Bryan G.

    2013-01-01

    Despite the unparalleled diversity of venomous snakes in Australia, research has concentrated on a handful of medically significant species and even of these very few toxins have been fully sequenced. In this study, venom gland transcriptomes were sequenced from eleven species of small Australian elapid snakes, from eleven genera, spanning a broad phylogenetic range. The particularly large number of sequences obtained for three-finger toxin (3FTx) peptides allowed for robust reconstructions of their dynamic molecular evolutionary histories. We demonstrated that each species preferentially favoured different types of α-neurotoxic 3FTx, probably as a result of differing feeding ecologies. The three forms of α-neurotoxin [Type I (also known as (aka): short-chain), Type II (aka: long-chain) and Type III] not only adopted differential rates of evolution, but have also conserved a diversity of residues, presumably to potentiate prey-specific toxicity. Despite these differences, the different α-neurotoxin types were shown to accumulate mutations in similar regions of the protein, largely in the loops and structurally unimportant regions, highlighting the significant role of focal mutagenesis. We theorize that this phenomenon not only affects toxin potency or specificity, but also generates necessary variation for preventing/delaying prey animals from acquiring venom-resistance. This study also recovered the first full-length sequences for multimeric phospholipase A2 (PLA2) ‘taipoxin/paradoxin’ subunits from non-Oxyuranus species, confirming the early recruitment of this extremely potent neurotoxin complex to the venom arsenal of Australian elapid snakes. We also recovered the first natriuretic peptides from an elapid that lack the derived C-terminal tail and resemble the plesiotypic form (ancestral character state) found in viper venoms. This provides supporting evidence for a single early recruitment of natriuretic peptides into snake venoms. Novel forms of kunitz

  6. Venom Down Under: Dynamic Evolution of Australian Elapid Snake Toxins

    Directory of Open Access Journals (Sweden)

    Timothy N. W. Jackson

    2013-12-01

    Full Text Available Despite the unparalleled diversity of venomous snakes in Australia, research has concentrated on a handful of medically significant species and even of these very few toxins have been fully sequenced. In this study, venom gland transcriptomes were sequenced from eleven species of small Australian elapid snakes, from eleven genera, spanning a broad phylogenetic range. The particularly large number of sequences obtained for three-finger toxin (3FTx peptides allowed for robust reconstructions of their dynamic molecular evolutionary histories. We demonstrated that each species preferentially favoured different types of α-neurotoxic 3FTx, probably as a result of differing feeding ecologies. The three forms of α-neurotoxin [Type I (also known as (aka: short-chain, Type II (aka: long-chain and Type III] not only adopted differential rates of evolution, but have also conserved a diversity of residues, presumably to potentiate prey-specific toxicity. Despite these differences, the different α-neurotoxin types were shown to accumulate mutations in similar regions of the protein, largely in the loops and structurally unimportant regions, highlighting the significant role of focal mutagenesis. We theorize that this phenomenon not only affects toxin potency or specificity, but also generates necessary variation for preventing/delaying prey animals from acquiring venom-resistance. This study also recovered the first full-length sequences for multimeric phospholipase A2 (PLA2 ‘taipoxin/paradoxin’ subunits from non-Oxyuranus species, confirming the early recruitment of this extremely potent neurotoxin complex to the venom arsenal of Australian elapid snakes. We also recovered the first natriuretic peptides from an elapid that lack the derived C-terminal tail and resemble the plesiotypic form (ancestral character state found in viper venoms. This provides supporting evidence for a single early recruitment of natriuretic peptides into snake venoms. Novel

  7. Expression pattern of three-finger toxin and phospholipase A2 genes in the venom glands of two sea snakes, Lapemis curtus and Acalyptophis peronii: comparison of evolution of these toxins in land snakes, sea kraits and sea snakes

    Science.gov (United States)

    Pahari, Susanta; Bickford, David; Fry, Bryan G; Kini, R Manjunatha

    2007-01-01

    Background Snake venom composition varies widely both among closely related species and within the same species, based on ecological variables. In terrestrial snakes, such variation has been proposed to be due to snakes' diet. Land snakes target various prey species including insects (arthropods), lizards (reptiles), frogs and toads (amphibians), birds (aves), and rodents (mammals), whereas sea snakes target a single vertebrate class (fishes) and often specialize on specific types of fish. It is therefore interesting to examine the evolution of toxins in sea snake venoms compared to that of land snakes. Results Here we describe the expression of toxin genes in the venom glands of two sea snakes, Lapemis curtus (Spine-bellied Sea Snake) and Acalyptophis peronii (Horned Sea Snake), two members of a large adaptive radiation which occupy very different ecological niches. We constructed cDNA libraries from their venom glands and sequenced 214 and 192 clones, respectively. Our data show that despite their explosive evolutionary radiation, there is very little variability in the three-finger toxin (3FTx) as well as the phospholipase A2 (PLA2) enzymes, the two main constituents of Lapemis curtus and Acalyptophis peronii venom. To understand the evolutionary trends among land snakes, sea snakes and sea kraits, pairwise genetic distances (intraspecific and interspecific) of 3FTx and PLA2 sequences were calculated. Results show that these proteins appear to be highly conserved in sea snakes in contrast to land snakes or sea kraits, despite their extremely divergent and adaptive ecological radiation. Conclusion Based on these results, we suggest that streamlining in habitat and diet in sea snakes has possibly kept their toxin genes conserved, suggesting the idea that prey composition and diet breadth may contribute to the diversity and evolution of venom components. PMID:17900344

  8. Pitfalls to avoid when using phage display for snake toxins.

    Science.gov (United States)

    Laustsen, Andreas Hougaard; Lauridsen, Line Præst; Lomonte, Bruno; Andersen, Mikael Rørdam; Lohse, Brian

    2017-02-01

    Antivenoms against bites and stings from snakes, spiders, and scorpions are associated with immunological side effects and high cost of production, since these therapies are still derived from the serum of hyper-immunized production animals. Biotechnological innovations within envenoming therapies are thus warranted, and phage display technology may be a promising avenue for bringing antivenoms into the modern era of biologics. Although phage display technology represents a robust and high-throughput approach for the discovery of antibody-based antitoxins, several pitfalls may present themselves when animal toxins are used as targets for phage display selection. Here, we report selected critical challenges from our own phage display experiments associated with biotinylation of antigens, clone picking, and the presence of amber codons within antibody fragment structures in some phage display libraries. These challenges may be detrimental to the outcome of phage display experiments, and we aim to help other researchers avoiding these pitfalls by presenting their solutions. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Computer modeling of binding of diverse weak toxins to nicotinic acetylcholine receptors.

    Science.gov (United States)

    Mordvitsev, D Yu; Polyak, Ya L; Kuzmin, D A; Levtsova, O V; Tourleigh, Ye V; Utkin, Yu N; Shaitan, K V; Tsetlin, V I

    2007-04-01

    Weak toxins are the "three-fingered" snake venoms toxins grouped together by having an additional disulfide in the N-terminal loop I. In general, weak toxins have low toxicity, and biological targets have been identified for some of them only, recently by detecting the effects on the nicotinic acetylcholine receptors (nAChR). Here the methods of docking and molecular dynamics simulations are used for comparative modeling of the complexes between four weak toxins of known spatial structure (WTX, candoxin, bucandin, gamma-bungarotoxin) and nAChRs. WTX and candoxin are those toxins whose blocking of the neuronal alpha7- and muscle-type nAChR has been earlier shown in binding assays and electrophysiological experiments, while for the other two toxins no such activity has been reported. Only candoxin and WTX are found here to give stable solutions for the toxin-nAChR complexes. These toxins appear to approach the binding site similarly to short alpha-neurotoxins, but their final position resembles that of alpha-cobratoxin, a long alpha-neurotoxin, in the complex with the acetylcholine-binding protein. The final spatial structures of candoxin and WTX complexes with the alpha7 neuronal or muscle-type nAChR are very similar and do not provide immediate answer why candoxin has a much higher affinity than WTX, but both of them share a virtually irreversible mode of binding to one or both these nAChR subtypes. Possible explanation comes from docking and MD simulations which predict fast kinetics of candoxin association with nAChR, no gross changes in the toxin conformation (with smaller toxin flexibility on alpha7 nAChR), while slow WTX binding to nAChR is associated with slow irreversible rearrangement both of the tip of the toxin loop II and of the binding pocket residues locking finally the toxin molecule. Computer modeling showed that the additional disulfide in the loop I is not directly involved in receptor binding of WTX and candoxin, but it stabilizes the structure of

  10. Toxin-resistant isoforms of Na+/K+-ATPase in snakes do not closely track dietary specialization on toads

    Science.gov (United States)

    Gonzalez, Jonathan; Takeuchi, Hirohiko; Mori, Akira

    2016-01-01

    Toads are chemically defended by bufadienolides, a class of cardiotonic steroids that exert toxic effects by binding to and disabling the Na+/K+-ATPases of cell membranes. Some predators, including a number of snakes, have evolved resistance to the toxic effects of bufadienolides and prey regularly on toads. Resistance in snakes to the acute effects of these toxins is conferred by at least two amino acid substitutions in the cardiotonic steroid binding pocket of the Na+/K+-ATPase. We surveyed 100 species of snakes from a broad phylogenetic range for the presence or absence of resistance-conferring mutations. We found that such mutations occur in a much wider range of taxa than previously believed. Although all sequenced species known to consume toads exhibited the resistance mutations, many of the species possessing the mutations do not feed on toads, much less specialize on that food source. This suggests that either there is little performance cost associated with these mutations or they provide an unknown benefit. Furthermore, the distribution of the mutation among major clades of advanced snakes suggests that the origin of the mutation reflects evolutionary retention more than dietary constraint. PMID:27852804

  11. Snake venomics: from the inventory of toxins to biology.

    Science.gov (United States)

    Calvete, Juan J

    2013-12-01

    A deep understanding of the composition of venoms and of the principles governing the evolution of venomous systems is of applied importance for exploring the enormous potential of venoms as sources of chemical and pharmacological novelty but also to fight the dire consequences of snakebite envenomings. This goal is now within the reach of "omic" technologies. A central thesis developed in this essay is the view that making sense of the huge inventory of data gathered through "omic" approaches requires the integration of this information across the biological system. Key to this is the identification of evolutionary and ecological trends; without the evolutionary link, systems venomics is relegated to a set of miscellaneous facts. The interplay between chance and adaptation plays a central role in the evolution of biological systems (Monod, 1970). However, the evolution of venomous species and their venoms do not always follow the same course, and the identification of structural and functional convergences and divergences among venoms is often unpredictable by a phylogenetic hypothesis. Toxins sharing a structural fold present in venoms from phylogenetically distant snakes often share antigenic determinants. The deficit of antivenom supply in certain regions of the world can be mitigated in part through the optimized use of existing antivenoms, and through the design of novel broad-range polyspecific antivenoms. Proteomics-guided identification of evolutionary and immunoreactivity trends among homologous and heterologous venoms may aid in the replacement of the traditional geographic- and phylogenetic-driven hypotheses for antivenom production strategies by a more rationale approach based on a hypothesis-driven systems venomics approach. Selected applications of venomics and antivenomics for exploring the chemical space and immunological profile of venoms will illustrate the author's views on the impact these proteomics tools may have in the field of toxinology

  12. Putting the brakes on snake venom evolution: the unique molecular evolutionary patterns of Aipysurus eydouxii (Marbled sea snake) phospholipase A2 toxins.

    Science.gov (United States)

    Li, Min; Fry, Bryan G; Kini, R Manjunatha

    2005-04-01

    Accelerated evolution of toxins is a unique feature of venoms, with the toxins evolving via the birth-and-death mode of molecular evolution. The venoms of sea snakes, however, are remarkably simple in comparison to those of land snakes, which contain highly complex venoms. Aipysurus eydouxii (Marbled sea snake) is a particularly unique sea snake, feeding exclusively upon fish eggs. Secondary to this ecological change, the fangs have been lost and the venom glands greatly atrophied. We recently showed that the only neurotoxin (a three-finger toxin) gene found in the sea snake A. eydouxii has a dinucleotide deletion, resulting in the loss of neurotoxic activity. During these studies, we isolated and identified a number of cDNA clones encoding isozymes of phospholipase A(2) (PLA(2)) toxins from its venom gland. Sixteen unique PLA(2) clones were sequenced from the cDNA library and TA cloning of reverse transcription-polymerase chain reaction products. Phylogenetic analysis of these clones revealed that less diversification of the PLA(2) toxins has occurred in the A. eydouxii venom gland in comparison to equivalent terrestrial and other marine snakes. As there is no longer a positive selection pressure acting upon the venom, mutations have accumulated in the toxin-coding regions that would have otherwise had a deleterious effect upon the ability to use the venom for prey capture. Such mutations include substitutions of highly conserved residues; in one clone, the active site His(48) is replaced by Arg, and in two other clones, highly conserved cysteine residues are replaced. These mutations significantly affect the functional and structural properties of these PLA(2) enzymes, respectively. Thus, in A. eydouxii, the loss of the main neurotoxin is accompanied by a much slower rate of molecular evolution of the PLA(2) toxins as a consequence of the snake's shift in ecological niche. This is the first case of decelerated evolution of toxins in snake venom.

  13. A heteromeric snake toxin and the molecular details of pain perception

    DEFF Research Database (Denmark)

    Strømgaard, Kristian; Kristensen, Anders Skov

    2012-01-01

    Gaining on pain: Two snake protein toxins combine to form a heteromeric complex, MitTx, which activates acid-sensing ion channels (ASICs) and elicits pain. MitTx is used to explore the roles of specific ASIC subtypes in pain pathways. These insights may provide new pharmacological tools ultimately...

  14. Identification of a novel snake peptide toxin displaying high affinity and antagonist behaviour for the α2-adrenoceptors.

    Science.gov (United States)

    Rouget, Céline; Quinton, Loïc; Maïga, Arhamatoulaye; Gales, Céline; Masuyer, Geoffrey; Malosse, Christian; Chamot-Rooke, Julia; Thai, Robert; Mourier, Gilles; De Pauw, Edwin; Gilles, Nicolas; Servent, Denis

    2010-11-01

    BACKGROUND AND PURPOSE Muscarinic and adrenergic G protein-coupled receptors (GPCRs) are the targets of rare peptide toxins isolated from snake or cone snail venoms. We used a screen to identify novel toxins from Dendroaspis angusticeps targeting aminergic GPCRs. These toxins may offer new candidates for the development of new tools and drugs. EXPERIMENTAL APPROACH In binding experiments with (3) H-rauwolscine, we studied the interactions of green mamba venom fractions with α(2) -adrenoceptors from rat brain synaptosomes. We isolated, sequenced and chemically synthesized a novel peptide, ρ-Da1b. This peptide was pharmacologically characterized using binding experiments and functional tests on human α(2)-adrenoceptors expressed in mammalian cells. KEY RESULTS ρ-Da1b, a 66-amino acid peptide stabilized by four disulphide bridges, belongs to the three-finger-fold peptide family. Its synthetic homologue inhibited 80% of (3) H-rauwolscine binding to the three α(2)-adrenoceptor subtypes, with an affinity between 14 and 73 nM and Hill slopes close to unity. Functional experiments on α(2A) -adrenoceptor demonstrated that ρ-Da1b is an antagonist, shifting adrenaline activation curves to the right. Schild regression revealed slopes of 0.97 and 0.67 and pA(2) values of 5.93 and 5.32 for yohimbine and ρ-Da1b, respectively. CONCLUSIONS AND IMPLICATIONS ρ-Da1b is the first toxin identified to specifically interact with α(2)-adrenoceptors, extending the list of class A GPCRs sensitive to toxins. Additionally, its affinity and atypical mode of interaction open up the possibility of its use as a new pharmacological tool, in the study of the physiological roles of α(2)-adrenoceptor subtypes. British Journal of Pharmacology © 2010 The British Pharmacological Society. No claim to original French government works.

  15. Pitfalls to avoid when using phage display for snake toxins

    DEFF Research Database (Denmark)

    Laustsen, Andreas Hougaard; Lauridsen, Line Præst; Lomonte, Bruno

    2017-01-01

    Antivenoms against bites and stings from snakes, spiders, and scorpions are associated with immunological side effects and high cost of production, since these therapies are still derived from the serum of hyper-immunized production animals. Biotechnological innovations within envenoming therapies...

  16. Binding of pertussis toxin to eucaryotic cells and glycoproteins.

    Science.gov (United States)

    Witvliet, M H; Burns, D L; Brennan, M J; Poolman, J T; Manclark, C R

    1989-01-01

    The binding of pertussis toxin and its subunits to cell surface receptors and purified glycoproteins was examined. The interaction of pertussis toxin with components of two variant Chinese hamster ovary (CHO) cell lines was studied. These cell lines are deficient in either sialic acid residues (LEC 2) or sialic acid and galactose residues (LEC 8) on cell surface macromolecules. The binding of pertussis toxin to components of these cells differed from the binding of the toxin to wild-type components. Although the toxin bound to a 165,000-dalton glycoprotein found in N-octylglucoside extracts of wild-type cells, it did not bind to components found in extracts of LEC 2 cells. In contrast, the toxin bound to components found in extracts of LEC 8 cells, which are variant cells that contain increased amounts of terminal N-acetylglucosamine residues on cell surface macromolecules. These results suggest that the receptor for pertussis toxin on CHO cells contains terminal acetamido-containing sugars. The cytopathic effect of the toxin on both types of variant cells was much reduced compared with its effects on wild-type cells. Thus, optimal functional binding of pertussis toxin appears to require a complete sialyllactosamine (NeuAc----Gal beta 4GlcNAc) sequence on surface macromolecules. In addition to studying the nature of the eucaryotic receptor for pertussis toxin, we examined corresponding binding sites for glycoproteins on the toxin molecule. Binding of both S2-S4 and S3-S4 dimers of the toxin to cellular components and purified glycoproteins was observed. The two dimers bound to a number of glycoproteins containing N-linked oligosaccharides but not O-linked oligosaccharides, and differences in the binding of the two dimers to some glycoproteins was noted. These data indicate that the holotoxin molecule contains at least two glycoprotein-binding sites which may have slightly different specificities for glycoproteins. Images PMID:2478471

  17. A synthetic biology approach for consistent production of plant-made recombinant polyclonal antibodies against snake venom toxins.

    Science.gov (United States)

    Julve Parreño, Jose Manuel; Huet, Estefanía; Fernández-Del-Carmen, Asun; Segura, Alvaro; Venturi, Micol; Gandía, Antoni; Pan, Wei-Song; Albaladejo, Irene; Forment, Javier; Pla, Davinia; Wigdorovitz, Andrés; Calvete, Juan J; Gutiérrez, Carlos; Gutiérrez, José María; Granell, Antonio; Orzáez, Diego

    2017-08-29

    Antivenoms developed from the plasma of hyperimmunized animals are the only effective treatment available against snakebite envenomation but shortage of supply contributes to the high morbidity and mortality toll of this tropical disease. We describe a synthetic biology approach to affordable and cost-effective antivenom production based on plant-made recombinant polyclonal antibodies (termed pluribodies). The strategy takes advantage of virus superinfection exclusion to induce the formation of somatic expression mosaics in agroinfiltrated plants, which enables the expression of complex antibody repertoires in a highly reproducible manner. Pluribodies developed using toxin-binding genetic information captured from peripheral blood lymphocytes of hyperimmunized camels recapitulated the overall binding activity of the immune response. Furthermore, an improved plant-made antivenom (plantivenom) was formulated using an in vitro selected pluribody against Bothrops asper snake venom toxins and has been shown to neutralize a wide range of toxin activities and provide protection against lethal venom doses in mice. © 2017 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

  18. Processing of Snake Venom Metalloproteinases: Generation of Toxin Diversity and Enzyme Inactivation

    Directory of Open Access Journals (Sweden)

    Ana M. Moura-da-Silva

    2016-06-01

    Full Text Available Snake venom metalloproteinases (SVMPs are abundant in the venoms of vipers and rattlesnakes, playing important roles for the snake adaptation to different environments, and are related to most of the pathological effects of these venoms in human victims. The effectiveness of SVMPs is greatly due to their functional diversity, targeting important physiological proteins or receptors in different tissues and in the coagulation system. Functional diversity is often related to the genetic diversification of the snake venom. In this review, we discuss some published evidence that posit that processing and post-translational modifications are great contributors for the generation of functional diversity and for maintaining latency or inactivation of enzymes belonging to this relevant family of venom toxins.

  19. Ancient Diversification of Three-Finger Toxins in Micrurus Coral Snakes.

    Science.gov (United States)

    Dashevsky, Daniel; Fry, Bryan G

    2018-01-01

    Coral snakes, most notably the genus Micrurus, are the only terrestrial elapid snakes in the Americas. Elapid venoms are generally known for their potent neurotoxicity which is usually caused by Three-Finger Toxin (3FTx) proteins. These toxins can have a wide array of functions that have been characterized from the venom of other elapids. We examined publicly available sequences from Micrurus 3FTx to show that they belong to 8 monophyletic clades that diverged as deep in the 3FTx phylogenetic tree as the other clades with characterized functions. Functional residues from previously characterized clades of 3FTx are not well conserved in most of the Micrurus toxin clades. We also analyzed the patterns of selection on these toxins and find that they have been diversifying at different rates, with some having undergone extreme diversifying selection. This suggests that Micrurus 3FTx may contain a previously underappreciated functional diversity that has implications for the clinical outcomes of bite victims, the evolution and ecology of the genus, as well as the potential for biodiscovery efforts focusing on these toxins.

  20. Pitfalls to avoid when using phage display for snake toxins

    DEFF Research Database (Denmark)

    Laustsen, Andreas Hougaard; Lauridsen, Line Præst; Lomonte, Bruno

    2017-01-01

    when animal toxins are used as targets for phage display selection. Here, we report selected critical challenges from our own phage display experiments associated with biotinylation of antigens, clone picking, and the presence of amber codons within antibody fragment structures in some phage display...

  1. Conformational Changes in Small Ligands Upon Tetanus Toxin Binding

    National Research Council Canada - National Science Library

    Henderson, Terry J; Gitti, Rossitza K

    2008-01-01

    ... A upon binding to tetanus toxin. C13 T1 measurements suggested that to a first approximation, the conformational behavior of doxorubicin in solution appears to be a composite of a rigid aromatic ring system, ring librations...

  2. Binding Affinity of Glycoconjugates to BACILLUS Spores and Toxins

    Science.gov (United States)

    Rasol, Aveen; Eassa, Souzan; Tarasenko, Olga

    2010-04-01

    Early recognition of Bacillus cereus group species is important since they can cause food-borne illnesses and deadly diseases in humans. Glycoconjugates (GCs) are carbohydrates covalently linked to non-sugar moieties including lipids, proteins or other entities. GCs are involved in recognition and signaling processes intrinsic to biochemical functions in cells. They also stimulate cell-cell adhesion and subsequent recognition and activation of receptors. We have demonstrated that GCs are involved in Bacillus cereus spore recognition. In the present study, we have investigated whether GCs possess the ability to bind and recognize B. cereus spores and Bacillus anthracis recombinant single toxins (sTX) and complex toxins (cTX). The affinity of GCs to spores + sTX and spores + cTX toxins was studied in the binding essay. Our results demonstrated that GC9 and GC10 were able to selectively bind to B. cereus spores and B. anthracis toxins. Different binding affinities for GCs were found toward Bacillus cereus spores + sTX and spores + cTX. Dilution of GCs does not impede the recognition and binding. Developed method provides a tool for simultaneous recognition and targeting of spores, bacteria toxins, and/or other entities.

  3. Venom gland transcriptomes of two elapid snakes (Bungarus multicinctus and Naja atra) and evolution of toxin genes

    National Research Council Canada - National Science Library

    Jiang, Yu; Li, Yan; Lee, Wenhui; Xu, Xun; Zhang, Yue; Zhao, Ruoping; Zhang, Yun; Wang, Wen

    2011-01-01

    ...) libraries for Bungarus multicinctus and Naja atra, respectively. We sequenced about 1500 cDNA clones for each of the venom cDNA libraries and screened BAC libraries of the two snakes by blot analysis using four kinds of toxin probes; i.e...

  4. Snake cytotoxins bind to membranes via interactions with phosphatidylserine head groups of lipids.

    Directory of Open Access Journals (Sweden)

    Anastasia G Konshina

    Full Text Available The major representatives of Elapidae snake venom, cytotoxins (CTs, share similar three-fingered fold and exert diverse range of biological activities against various cell types. CT-induced cell death starts from the membrane recognition process, whose molecular details remain unclear. It is known, however, that the presence of anionic lipids in cell membranes is one of the important factors determining CT-membrane binding. In this work, we therefore investigated specific interactions between one of the most abundant of such lipids, phosphatidylserine (PS, and CT 4 of Naja kaouthia using a combined, experimental and modeling, approach. It was shown that incorporation of PS into zwitterionic liposomes greatly increased the membrane-damaging activity of CT 4 measured by the release of the liposome-entrapped calcein fluorescent dye. The CT-induced leakage rate depends on the PS concentration with a maximum at approximately 20% PS. Interestingly, the effects observed for PS were much more pronounced than those measured for another anionic lipid, sulfatide. To delineate the potential PS binding sites on CT 4 and estimate their relative affinities, a series of computer simulations was performed for the systems containing the head group of PS and different spatial models of CT 4 in aqueous solution and in an implicit membrane. This was done using an original hybrid computational protocol implementing docking, Monte Carlo and molecular dynamics simulations. As a result, at least three putative PS-binding sites with different affinities to PS molecule were delineated. Being located in different parts of the CT molecule, these anion-binding sites can potentially facilitate and modulate the multi-step process of the toxin insertion into lipid bilayers. This feature together with the diverse binding affinities of the sites to a wide variety of anionic targets on the membrane surface appears to be functionally meaningful and may adjust CT action against

  5. The Snake with the Scorpion's Sting: Novel Three-Finger Toxin Sodium Channel Activators from the Venom of the Long-Glanded Blue Coral Snake (Calliophis bivirgatus).

    Science.gov (United States)

    Yang, Daryl C; Deuis, Jennifer R; Dashevsky, Daniel; Dobson, James; Jackson, Timothy N W; Brust, Andreas; Xie, Bing; Koludarov, Ivan; Debono, Jordan; Hendrikx, Iwan; Hodgson, Wayne C; Josh, Peter; Nouwens, Amanda; Baillie, Gregory J; Bruxner, Timothy J C; Alewood, Paul F; Lim, Kelvin Kok Peng; Frank, Nathaniel; Vetter, Irina; Fry, Bryan G

    2016-10-18

    Millions of years of evolution have fine-tuned the ability of venom peptides to rapidly incapacitate both prey and potential predators. Toxicofera reptiles are characterized by serous-secreting mandibular or maxillary glands with heightened levels of protein expression. These glands are the core anatomical components of the toxicoferan venom system, which exists in myriad points along an evolutionary continuum. Neofunctionalisation of toxins is facilitated by positive selection at functional hotspots on the ancestral protein and venom proteins have undergone dynamic diversification in helodermatid and varanid lizards as well as advanced snakes. A spectacular point on the venom system continuum is the long-glanded blue coral snake ( Calliophis bivirgatus ), a specialist feeder that preys on fast moving, venomous snakes which have both a high likelihood of prey escape but also represent significant danger to the predator itself. The maxillary venom glands of C. bivirgatus extend one quarter of the snake's body length and nestle within the rib cavity. Despite the snake's notoriety its venom has remained largely unstudied. Here we show that the venom uniquely produces spastic paralysis, in contrast to the flaccid paralysis typically produced by neurotoxic snake venoms. The toxin responsible, which we have called calliotoxin (δ-elapitoxin-Cb1a), is a three-finger toxin (3FTx). Calliotoxin shifts the voltage-dependence of Na V 1.4 activation to more hyperpolarised potentials, inhibits inactivation, and produces large ramp currents, consistent with its profound effects on contractile force in an isolated skeletal muscle preparation. Voltage-gated sodium channels (Na V ) are a particularly attractive pharmacological target as they are involved in almost all physiological processes including action potential generation and conduction. Accordingly, venom peptides that interfere with Na V function provide a key defensive and predatory advantage to a range of invertebrate

  6. Snakes! Snakes! Snakes!

    Science.gov (United States)

    Nature Naturally, 1983

    1983-01-01

    Designed for students in grades 4-6, the teaching unit presents illustrations and facts about snakes. Topics include common snakes found in the United States, how snakes eat, how snakes shed their skin, poisonous snakes, the Eastern Indigo snake, and the anatomy of a snake. A student page includes a crossword puzzle and surprising snake facts. A…

  7. Three-Fingered RAVERs: Rapid Accumulation of Variations in Exposed Residues of Snake Venom Toxins

    Science.gov (United States)

    Sunagar, Kartik; Jackson, Timothy N. W.; Undheim, Eivind A. B.; Ali, Syed. A.; Antunes, Agostinho; Fry, Bryan G.

    2013-01-01

    Three-finger toxins (3FTx) represent one of the most abundantly secreted and potently toxic components of colubrid (Colubridae), elapid (Elapidae) and psammophid (Psammophiinae subfamily of the Lamprophidae) snake venom arsenal. Despite their conserved structural similarity, they perform a diversity of biological functions. Although they are theorised to undergo adaptive evolution, the underlying diversification mechanisms remain elusive. Here, we report the molecular evolution of different 3FTx functional forms and show that positively selected point mutations have driven the rapid evolution and diversification of 3FTx. These diversification events not only correlate with the evolution of advanced venom delivery systems (VDS) in Caenophidia, but in particular the explosive diversification of the clade subsequent to the evolution of a high pressure, hollow-fanged VDS in elapids, highlighting the significant role of these toxins in the evolution of advanced snakes. We show that Type I, II and III α-neurotoxins have evolved with extreme rapidity under the influence of positive selection. We also show that novel Oxyuranus/Pseudonaja Type II forms lacking the apotypic loop-2 stabilising cysteine doublet characteristic of Type II forms are not phylogenetically basal in relation to other Type IIs as previously thought, but are the result of secondary loss of these apotypic cysteines on at least three separate occasions. Not all 3FTxs have evolved rapidly: κ-neurotoxins, which form non-covalently associated heterodimers, have experienced a relatively weaker influence of diversifying selection; while cytotoxic 3FTx, with their functional sites, dispersed over 40% of the molecular surface, have been extremely constrained by negative selection. We show that the a previous theory of 3FTx molecular evolution (termed ASSET) is evolutionarily implausible and cannot account for the considerable variation observed in very short segments of 3FTx. Instead, we propose a theory of

  8. Snake alpha-neurotoxin binding site on the Egyptian cobra (Naja haje) nicotinic acetylcholine receptor Is conserved.

    Science.gov (United States)

    Takacs, Z; Wilhelmsen, K C; Sorota, S

    2001-09-01

    Evolutionary success requires that animal venoms are targeted against phylogenetically conserved molecular structures of fundamental physiological processes. Species producing venoms must be resistant to their action. Venoms of Elapidae snakes (e.g., cobras, kraits) contain alpha-neurotoxins, represented by alpha-bungarotoxin (alpha-BTX) targeted against the nicotinic acetylcholine receptor (nAChR) of the neuromuscular junction. The model which presumes that cobras (Naja spp., Elapidae) have lost their binding site for conspecific alpha-neurotoxins because of the unique amino acid substitutions in their nAChR polypeptide backbone per se is incompatible with the evolutionary theory that (1) the molecular motifs forming the alpha-neurotoxin target site on the nAChR are fundamental for receptor structure and/or function, and (2) the alpha-neurotoxin target site is conserved among Chordata lineages. To test the hypothesis that the alpha-neurotoxin binding site is conserved in Elapidae snakes and to identify the mechanism of resistance against conspecific alpha-neurotoxins, we cloned the ligand binding domain of the Egyptian cobra (Naja haje) nAChR alpha subunit. When expressed as part of a functional Naja/mouse chimeric nAChR in Xenopus oocytes, this domain confers resistance against alpha-BTX but does not alter responses induced by the natural ligand acetylcholine. Further mutational analysis of the Naja/mouse nAChR demonstrated that an N-glycosylation signal in the ligand binding domain that is unique to N. haje is responsible for alpha-BTX resistance. However, when the N-glycosylation signal is eliminated, the nAChR containing the N. haje sequence is inhibited by alpha-BTX with a potency that is comparable to that in mammals. We conclude that the binding site for conspecific alpha-neurotoxin in Elapidae snakes is conserved in the nAChR ligand binding domain polypeptide backbone per se. This conclusion supports the hypothesis that animal toxins are targeted against

  9. Bacillus thuringiensis Cry1Aa toxin-binding region of Bombyx mori aminopeptidase N.

    Science.gov (United States)

    Yaoi, K; Nakanishi, K; Kadotani, T; Imamura, M; Koizumi, N; Iwahana, H; Sato, R

    1999-12-17

    The Bacillus thuringiensis Cry1Aa toxin-binding region of Bombyx mori aminopeptidase N (APN) was analyzed, to better understand the molecular mechanism of susceptibility to the toxin and the development of resistance in insects. APN was digested with lysylendopeptidase and the ability of the resulting fragments to bind to Cry1Aa and 1Ac toxins was examined. The binding abilities of the two toxins to these fragments were different. The Cry1Aa toxin bound to the fragment containing 40-Asp to 313-Lys, suggesting that the Cry1Aa toxin-binding site is located in the region between 40-Asp and 313-Lys, while Cry1Ac toxin bound exclusively to mature APN. Next, recombinant APN of various lengths was expressed in Escherichia coli cells and its ability to bind to Cry1Aa toxin was examined. The results localized the Cry1Aa toxin binding to the region between 135-Ile and 198-Pro.

  10. Identification and molecular characterization of five putative toxins from the venom gland of the snake Philodryas chamissonis (Serpentes: Dipsadidae).

    Science.gov (United States)

    Urra, Félix A; Pulgar, Rodrigo; Gutiérrez, Ricardo; Hodar, Christian; Cambiazo, Verónica; Labra, Antonieta

    2015-12-15

    Philodryas chamissonis is a rear-fanged snake endemic to Chile. Its bite produces mild to moderate symptoms with proteolytic and anti-coagulant effects. Presently, the composition of the venom, as well as, the biochemical and structural characteristics of its toxins, remains unknown. In this study, we cloned and reported the first full-length sequences of five toxin-encoding genes from the venom gland of this species: Type III snake venom metalloprotease (SVMP), snake venom serine protease (SVSP), Cysteine-rich secretory protein (CRISP), α and β subunits of C-type lectin-like protein (CLP) and C-type natriuretic peptide (NP). These genes are highly expressed in the venom gland and their sequences exhibited a putative signal peptide, suggesting that these are components of the venom. These putative toxins had different evolutionary relationships with those reported for some front-fanged snakes, being SVMP, SVSP and CRISP of P. chamissonis closely related to the toxins present in Elapidae species, while NP was more related to those of Viperidae species. In addition, analyses suggest that the α and β subunits of CLP of P. chamissonis might have a α-subunit scaffold in common with Viperidae species, whose highly variable C-terminal region might have allowed the diversification in α and β subunits. Our results provide the first molecular description of the toxins possibly implicated in the envenomation of prey and humans by the bite of P. chamissonis. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Binding Affinity and Capacity for the Uremic Toxin Indoxyl Sulfate

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    Eric Devine

    2014-01-01

    Full Text Available Protein binding prevents uremic toxins from removal by conventional extracorporeal therapies leading to accumulation in maintenance dialysis patients. Weakening of the protein binding may enhance the dialytic elimination of these toxins. In ultrafiltration and equilibrium dialysis experiments, different measures to modify the plasma binding affinity and capacity were tested: (i, increasing the sodium chloride (NaCl concentration to achieve a higher ionic strength; (ii, increasing the temperature; and (iii, dilution. The effects on the dissociation constant KD and the protein bound fraction of the prototypical uremic toxin indoxyl sulfate (IS in plasma of healthy and uremic individuals were studied. Binding of IS corresponded to one site binding in normal plasma. KD increased linearly with the NaCl concentration between 0.15 (KD = 13.2 ± 3.7 µM and 0.75 M (KD = 56.2 ± 2.0 µM. Plasma dilution further reduced the protein bound toxin fraction by lowering the protein binding capacity of the plasma. Higher temperatures also decreased the protein bound fraction of IS in human plasma. Increasing the NaCl concentration was effective to weaken the binding of IS also in uremic plasma: the protein bound fraction decreased from 89% ± 3% to 81% ± 3% at 0.15 and 0.75 M NaCl, respectively. Dilution and increasing the ionic strength and temperature enhance the free fraction of IS allowing better removal of the substance during dialysis. Applied during clinical dialysis, this may have beneficial effects on the long-term outcome of maintenance dialysis patients.

  12. Venom gland transcriptomes of two elapid snakes (Bungarus multicinctus and Naja atra) and evolution of toxin genes

    Science.gov (United States)

    2011-01-01

    Background Kraits (genus Bungarus) and cobras (genus Naja) are two representative toxic genera of elapids in the old world. Although they are closely related genera and both of their venoms are very toxic, the compositions of their venoms are very different. To unveil their detailed venoms and their evolutionary patterns, we constructed venom gland cDNA libraries and genomic bacterial artificial chromosome (BAC) libraries for Bungarus multicinctus and Naja atra, respectively. We sequenced about 1500 cDNA clones for each of the venom cDNA libraries and screened BAC libraries of the two snakes by blot analysis using four kinds of toxin probes; i.e., three-finger toxin (3FTx), phospholipase A2 (PLA2), kunitz-type protease inhibitor (Kunitz), and natriuretic peptide (NP). Results In total, 1092 valid expressed sequences tags (ESTs) for B. multicinctus and 1166 ESTs for N. atra were generated. About 70% of these ESTs can be annotated as snake toxin transcripts. 3FTx (64.5%) and β bungarotoxin (25.1%) comprise the main toxin classes in B. multicinctus, while 3FTx (95.8%) is the dominant toxin in N. atra. We also observed several less abundant venom families in B. multicinctus and N. atra, such as PLA2, C-type lectins, and Kunitz. Peculiarly a cluster of NP precursors with tandem NPs was detected in B. multicinctus. A total of 71 positive toxin BAC clones in B. multicinctus and N. atra were identified using four kinds of toxin probes (3FTx, PLA2, Kunitz, and NP), among which 39 3FTx-postive BACs were sequenced to reveal gene structures of 3FTx toxin genes. Conclusions Based on the toxin ESTs and 3FTx gene sequences, the major components of B. multicinctus venom transcriptome are neurotoxins, including long chain alpha neurotoxins (α-ntx) and the recently originated β bungarotoxin, whereas the N. atra venom transcriptome mainly contains 3FTxs with cytotoxicity and neurotoxicity (short chain α-ntx). The data also revealed that tandem duplications contributed the most to

  13. Tetanus toxin binding to mouse spinal cord cells: an evaluation of the role of gangliosides in toxin internalization.

    Science.gov (United States)

    Parton, R G; Ockleford, C D; Critchley, D R

    1988-12-13

    Studies on the binding of 125I-labelled tetanus toxin to mouse spinal cord cell cultures revealed two classes of toxin acceptor, one a high-affinity protease-sensitive site, the other a lower affinity protease-resistant site. The latter was shown to be sialidase-sensitive and may represent binding to gangliosides. Tetanus toxin internalization by spinal cord cells is rapid and coated pits have been implicated in the process (Parton et al. J. Neurochem., 49 (1987) 1057-1068). To investigate the role of gangliosides in the internalization process, trisialoganglioside was incorporated into the plasma membrane of Balb/c 3T3 cells which lack endogenous toxin-binding activity. 125I-labelled tetanus toxin bound specifically to ganglioside treated cells at 4 degrees C. On warming cells to 37 degrees C, a proportion of bound toxin was degraded indicating that some internalization of toxin had occurred. The mechanism of internalization was studied using tetanus toxin adsorbed to colloidal gold. At 4 degrees C, toxin-gold was concentrated in non-coated cell surface membrane invaginations. On warming cells to 37 degrees C, toxin gold was internalized via non-coated vesicles and accumulated within multivesicular bodies and lysosomes. The relative roles of coated and non-coated vesicular uptake systems in the mechanism of action of tetanus toxin are discussed.

  14. Identification and characterization of B-cell epitopes of 3FTx and PLA(2) toxins from Micrurus corallinus snake venom.

    Science.gov (United States)

    Castro, K L; Duarte, C G; Ramos, H R; Machado de Avila, R A; Schneider, F S; Oliveira, D; Freitas, C F; Kalapothakis, E; Ho, P L; Chávez-Olortegui, C

    2015-01-01

    The main goal of this work was to develop a strategy to identify B-cell epitopes on four different three finger toxins (3FTX) and one phospholipase A2 (PLA2) from Micrurus corallinus snake venom. 3FTx and PLA2 are highly abundant components in Elapidic venoms and are the major responsibles for the toxicity observed in envenomation by coral snakes. Overlapping peptides from the sequence of each toxin were prepared by SPOT method and three different anti-elapidic sera were used to map the epitopes. After immunogenicity analysis of the spot-reactive peptides by EPITOPIA, a computational method, nine sequences from the five toxins were chemically synthesized and antigenically and immunogenically characterized. All the peptides were used together as immunogens in rabbits, delivered with Freund's adjuvant for a first cycle of immunization and Montanide in the second. A good antibody response against individual synthetic peptides and M. corallinus venom was achieved. Anti-peptide IgGs were also cross-reactive against Micrurus frontalis and Micrurus lemniscatus crude venoms. In addition, anti-peptide IgGs inhibits the lethal and phospholipasic activities of M. corallinus crude venom. Our results provide a rational basis to the identification of neutralizing epitopes on coral snake toxins and show that their corresponding synthetic peptides could improve the generation of immuno-therapeutics. The use of synthetic peptide for immunization is a reasonable approach, since it enables poly-specificity, low risk of toxic effects and large scale production. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Exploration of immunoglobulin transcriptomes from mice immunized with three-finger toxins and phospholipases A2from the Central American coral snake,Micrurus nigrocinctus.

    Science.gov (United States)

    Laustsen, Andreas H; Engmark, Mikael; Clouser, Christopher; Timberlake, Sonia; Vigneault, Francois; Gutiérrez, José María; Lomonte, Bruno

    2017-01-01

    Snakebite envenomings represent a neglected public health issue in many parts of the rural tropical world. Animal-derived antivenoms have existed for more than a hundred years and are effective in neutralizing snake venom toxins when timely administered. However, the low immunogenicity of many small but potent snake venom toxins represents a challenge for obtaining a balanced immune response against the medically relevant components of the venom. Here, we employ high-throughput sequencing of the immunoglobulin (Ig) transcriptome of mice immunized with a three-finger toxin and a phospholipase A 2 from the venom of the Central American coral snake, Micrurus nigrocinctus. Although exploratory in nature, our indicate results showed that only low frequencies of mRNA encoding IgG isotypes, the most relevant isotype for therapeutic purposes, were present in splenocytes of five mice immunized with 6 doses of the two types of toxins over 90 days. Furthermore, analysis of Ig heavy chain transcripts showed that no particular combination of variable (V) and joining (J) gene segments had been selected in the immunization process, as would be expected after a strong humoral immune response to a single antigen. Combined with the titration of toxin-specific antibodies in the sera of immunized mice, these data support the low immunogenicity of three-finger toxins and phospholipases A 2 found in M. nigrocinctus venoms, and highlight the need for future studies analyzing the complexity of antibody responses to toxins at the molecular level.

  16. Exploration of immunoglobulin transcriptomes from mice immunized with three-finger toxins and phospholipases A2 from the Central American coral snake, Micrurus nigrocinctus

    Directory of Open Access Journals (Sweden)

    Andreas H. Laustsen

    2017-01-01

    Full Text Available Snakebite envenomings represent a neglected public health issue in many parts of the rural tropical world. Animal-derived antivenoms have existed for more than a hundred years and are effective in neutralizing snake venom toxins when timely administered. However, the low immunogenicity of many small but potent snake venom toxins represents a challenge for obtaining a balanced immune response against the medically relevant components of the venom. Here, we employ high-throughput sequencing of the immunoglobulin (Ig transcriptome of mice immunized with a three-finger toxin and a phospholipase A2 from the venom of the Central American coral snake, Micrurus nigrocinctus. Although exploratory in nature, our indicate results showed that only low frequencies of mRNA encoding IgG isotypes, the most relevant isotype for therapeutic purposes, were present in splenocytes of five mice immunized with 6 doses of the two types of toxins over 90 days. Furthermore, analysis of Ig heavy chain transcripts showed that no particular combination of variable (V and joining (J gene segments had been selected in the immunization process, as would be expected after a strong humoral immune response to a single antigen. Combined with the titration of toxin-specific antibodies in the sera of immunized mice, these data support the low immunogenicity of three-finger toxins and phospholipases A2found in M. nigrocinctusvenoms, and highlight the need for future studies analyzing the complexity of antibody responses to toxins at the molecular level.

  17. A toxin-binding alkaline phosphatase fragment synergizes Bt toxin Cry1Ac against susceptible and resistant Helicoverpa armigera.

    Directory of Open Access Journals (Sweden)

    Wenbo Chen

    Full Text Available Evolution of resistance by insects threatens the continued success of pest control using insecticidal crystal (Cry proteins from the bacterium Bacillus thuringiensis (Bt in sprays and transgenic plants. In this study, laboratory selection with Cry1Ac yielded five strains of cotton bollworm, Helicoverpa armigera, with resistance ratios at the median lethal concentration (LC50 of activated Cry1Ac ranging from 22 to 1700. Reduced activity and reduced transcription of an alkaline phosphatase protein that binds Cry1Ac was associated with resistance to Cry1Ac in the four most resistant strains. A Cry1Ac-binding fragment of alkaline phosphatase from H. armigera (HaALP1f was not toxic by itself, but it increased mortality caused by Cry1Ac in a susceptible strain and in all five resistant strains. Although synergism of Bt toxins against susceptible insects by toxin-binding fragments of cadherin and aminopeptidase N has been reported previously, the results here provide the first evidence of synergism of a Bt toxin by a toxin-binding fragment of alkaline phosphatase. The results here also provide the first evidence of synergism of a Bt toxin by any toxin-binding peptide against resistant insects.

  18. Lachesis muta (Viperidae) cDNAs reveal diverging pit viper molecules and scaffolds typical of cobra (Elapidae) venoms: implications for snake toxin repertoire evolution.

    Science.gov (United States)

    Junqueira-de-Azevedo, Inácio L M; Ching, Ana T C; Carvalho, Eneas; Faria, Fernanda; Nishiyama, Milton Y; Ho, Paulo L; Diniz, Marcelo R V

    2006-06-01

    Efforts to describe toxins from the two major families of venomous snakes (Viperidae and Elapidae) usually reveal proteins belonging to few structural types, particular of each family. Here we carried on an effort to determine uncommon cDNAs that represent possible new toxins from Lachesis muta (Viperidae). In addition to nine classes of typical toxins, atypical molecules never observed in the hundreds of Viperidae snakes studied so far are highly expressed: a diverging C-type lectin that is related to Viperidae toxins but appears to be independently originated; an ohanin-like toxin, which would be the third member of the most recently described class of Elapidae toxins, related to human butyrophilin and B30.2 proteins; and a 3FTx-like toxin, a new member of the widely studied three-finger family of proteins, which includes major Elapidae neurotoxins and CD59 antigen. The presence of these common and uncommon molecules suggests that the repertoire of toxins could be more conserved between families than has been considered, and their features indicate a dynamic process of venom evolution through molecular mechanisms, such as multiple recruitments of important scaffolds and domain exchange between paralogs, always keeping a minimalist nature in most toxin structures in opposition to their nontoxin counterparts.

  19. Structure-function relationship in the binding of snake neurotoxins to the torpedo membrane receptor.

    Science.gov (United States)

    Chicheportiche, R; Vincent, J P; Kopeyan, C; Schweitz, H; Lazdunski, M

    1975-05-20

    The Cys30-Cus34 bridge present in all long neutotoxins (71-74 amino acids, 5 disulfide bridges), but not in short toxins (60-63 amino acids, 4 disulfide bridges), is exposed at the surface since it can be reduced rapidly and selectively by sodium borohydride. Reduction and alkylation of the Cys30-Cys34 bridge of Naja haje neurotoxin III hardly alter the conformational properties of this model long toxin. Although alkylation by iodoacetic acid of th -SH groups liberated by reduction abolishes the toxicity, alkylation by iodoacetamide or ethylenimine does not affect the curarizing efficacy of the toxin. The Cys30-Cys34 bridge is not very important for the toxic activity of long neurotoxins. Reduction of the Cys30-Cys34 bridge followed by alkylation with radioactive iodoacetamide gave a labeled and active toxin which is a convenient derivative for binding experiments to the toxin receptor in membranes of the Torpedo electric organ. The binding capacity of these membrane is 1200 pmol of toxin/mg of membrane protein. The dissociation constant of the modified toxin-receptor complex at pH 7.4, 20 degrees is 10 minus 8m. Reduction with carbroxamidomethylation of the Cys30-Cys34 bridge decreases the affinity of the native Naja haje toxin only by a factor of 15. Carboxymethylation after reduction prevents binding to the membrane receptor. The binding properties of the derivative obtained by reduction and aminoethylation of Cys30-Cys34 are very similar to those of native neurotoxin III; the affinity is decreased only by a factor of 5. Binding properties to Toredo membrane of long neurotoxins (Naja haje neurotoxin III) and short neurotoxins (Naje haje toxin I and Naja mossambica toxin I) have been compared. Dissociation constants of receptor-long neurotoxin and receptor-short neurotoxin complexes are very similar (5.7 minus 8.2 times 10(-10) M at pH 7.4, 20degrees. However, the kinetics of complex formation and complex dissociation are quite different. Short neurotoxins

  20. Snake venomics of monocled cobra (Naja kaouthia) and investigation of human IgG response against venom toxins.

    Science.gov (United States)

    Laustsen, Andreas H; Gutiérrez, José María; Lohse, Brian; Rasmussen, Arne R; Fernández, Julián; Milbo, Christina; Lomonte, Bruno

    2015-06-01

    The venom proteome of the monocled cobra, Naja kaouthia, from Thailand, was characterized by RP-HPLC, SDS-PAGE, and MALDI-TOF-TOF analyses, yielding 38 different proteins that were either identified or assigned to families. Estimation of relative protein abundances revealed that venom is dominated by three-finger toxins (77.5%; including 24.3% cytotoxins and 53.2% neurotoxins) and phospholipases A2 (13.5%). It also contains lower proportions of components belonging to nerve growth factor, ohanin/vespryn, cysteine-rich secretory protein, C-type lectin/lectin-like, nucleotidase, phosphodiesterase, metalloproteinase, l-amino acid oxidase, cobra venom factor, and cytidyltransferase protein families. Small amounts of three nucleosides were also evidenced: adenosine, guanosine, and inosine. The most relevant lethal components, categorized by means of a 'toxicity score', were α-neurotoxins, followed by cytotoxins/cardiotoxins. IgGs isolated from a person who had repeatedly self-immunized with a variety of snake venoms were immunoprofiled by ELISA against all venom fractions. Stronger responses against larger toxins, but lower against the most critical α-neurotoxins were obtained. As expected, no neutralization potential against N. kaouthia venom was therefore detected. Combined, our results display a high level of venom complexity, unveil the most relevant toxins to be neutralized, and provide prospects of discovering human IgGs with toxin neutralizing abilities through use of phage display screening. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Proteomic analysis of the venom from the fish eating coral snake Micrurus surinamensis: novel toxins, their function and phylogeny.

    Science.gov (United States)

    Olamendi-Portugal, Timoteo; Batista, Cesar V F; Restano-Cassulini, Rita; Pando, Victoria; Villa-Hernandez, Oscar; Zavaleta-Martínez-Vargas, Alfonso; Salas-Arruz, Maria C; Rodríguez de la Vega, Ricardo C; Becerril, Baltazar; Possani, Lourival D

    2008-05-01

    The protein composition of the soluble venom from the South American fish-eating coral snake Micrurus surinamensis surinamensis, here abbreviated M. surinamensis, was separated by RP-HPLC and 2-DE, and their components were analyzed by automatic Edman degradation, MALDI-TOF and ESI-MS/MS. Approximately 100 different molecules were identified. Sixty-two components possess molecular masses between 6 and 8 kDa, are basically charged molecules, among which are cytotoxins and neurotoxins lethal to fish (Brachidanios rerio). Six new toxins (abbreviated Ms1-Ms5 and Ms11) were fully sequenced. Amino acid sequences similar to the enzymes phospholipase A2 and amino acid oxidase were identified. Over 20 additional peptides were identified by sequencing minor components of the HPLC separation and from 2-DE gels. A functional assessment of the physiological activity of the six toxins was also performed by patch clamp using muscular nicotinic acetylcholine receptor assays. Variable degrees of blockade were observed, most of them reversible. The structural and functional data obtained were used for phylogenetic analysis, providing information on some evolutionary aspects of the venom components of this snake. This contribution increases by a factor of two the total number of alpha-neurotoxins sequenced from the Micrurus genus in currently available literature.

  2. Surface binding of toxins and heavy metals by probiotics.

    Science.gov (United States)

    Zoghi, Alaleh; Khosravi-Darani, Kianoush; Sohrabvandi, Sara

    2014-01-01

    Removal of toxic metals and toxins using microbial biomass has been introduced as an inexpensive, new promising method on top of conventional methods for decontamination of food, raw material and concentrated. In this article the potential application of lactic acid bacteria and yeasts as the most familiar probiotics to eliminate, inactivate or reduce bioavailability of contamination in foods and feed has been reviewed. After fast glance to beneficial health effects and preservative properties of lactic acid bacteria, the mechanisms which explain antibacterial and antifungal efficiency as well as their antifungal metabolites are mentioned. Then the article has been focused on potential application of single strain or combination of lactic acid bacteria for removal of heavy metals (copper, lead, cadmium, chromium, arsenic), cyanotoxins (microcystin-LR, -RR, -LF) and mycotoxins (aflatoxin B1, B2, B2a, M1, M2, G1, G2, patulin, ochratoxin A, deoxynivalenol, fumonisin B1 and B2, 3-acetyldeoxynivalenol, deoxynivalenol, fusarenon, nivalenol, diacetoxyscirpenol, HT-2 and T-2 toxin, zearalenone and its derivative, etc) from aqueous solutions in vitro. Wherever possible the mechanism of decontamination and the factors influencing yield of removal are discussed. Some factors which can facilitate metal removal capacity of lactic acid bacteria including the strains, surface charge, pH, temperature, presence of other cations are introduced. The cell wall structure of lactic acid bacteria and yeasts are also introduced for further explanation of mechanism of action in complex binding of probiotic to contaminants and strength of mycotoxin- bacterium interaction.

  3. Trends in the Evolution of Snake Toxins Underscored by an Integrative Omics Approach to Profile the Venom of the Colubrid Phalotris mertensi.

    Science.gov (United States)

    Campos, Pollyanna Fernandes; Andrade-Silva, Débora; Zelanis, André; Paes Leme, Adriana Franco; Rocha, Marisa Maria Teixeira; Menezes, Milene Cristina; Serrano, Solange M T; Junqueira-de-Azevedo, Inácio de Loiola Meirelles

    2016-08-16

    Only few studies on snake venoms were dedicated to deeply characterize the toxin secretion of animals from the Colubridae family, despite the fact that they represent the majority of snake diversity. As a consequence, some evolutionary trends observed in venom proteins that underpinned the evolutionary histories of snake toxins were based on data from a minor parcel of the clade. Here, we investigated the proteins of the totally unknown venom from Phalotris mertensi (Dipsadinae subfamily), in order to obtain a detailed profile of its toxins and to appreciate evolutionary tendencies occurring in colubrid venoms. By means of integrated omics and functional approaches, including RNAseq, Sanger sequencing, high-resolution proteomics, recombinant protein production, and enzymatic tests, we verified an active toxic secretion containing up to 21 types of proteins. A high content of Kunitz-type proteins and C-type lectins were observed, although several enzymatic components such as metalloproteinases and an L-amino acid oxidase were also present in the venom. Interestingly, an arguable venom component of other species was demonstrated as a true venom protein and named svLIPA (snake venom acid lipase). This finding indicates the importance of checking the actual protein occurrence across species before rejecting genes suggested to code for toxins, which are relevant for the discussion about the early evolution of reptile venoms. Moreover, trends in the evolution of some toxin classes, such as simplification of metalloproteinases and rearrangements of Kunitz and Wap domains, parallel similar phenomena observed in other venomous snake families and provide a broader picture of toxin evolution. © The Author 2016. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  4. Binding properties of Clostridium botulinum type C progenitor toxin to mucins.

    Science.gov (United States)

    Nakamura, Toshio; Takada, Noriko; Tonozuka, Takashi; Sakano, Yoshiyuki; Oguma, Keiji; Nishikawa, Atsushi

    2007-04-01

    It has been reported that Clostridium botulinum type C 16S progenitor toxin (C16S toxin) first binds to the sialic acid on the cell surface of mucin before invading cells [A. Nishikawa, N. Uotsu, H. Arimitsu, J.C. Lee, Y. Miura, Y. Fujinaga, H. Nakada, T. Watanabe, T. Ohyama, Y. Sakano, K. Oguma, The receptor and transporter for internalization of Clostridium botulinum type C progenitor toxin into HT-29 cells, Biochem. Biophys. Res. Commun. 319 (2004) 327-333]. In this study we investigated the binding properties of the C16S toxin to glycoproteins. Although the toxin bound to membrane blotted mucin derived from the bovine submaxillary gland (BSM), which contains a lot of sialyl oligosaccharides, it did not bind to neuraminidase-treated BSM. The binding of the toxin to BSM was inhibited by N-acetylneuraminic acid, N-glycolylneuraminic acid, and sialyl oligosaccharides strongly, but was not inhibited by neutral oligosaccharides. Both sialyl alpha2-3 lactose and sialyl alpha2-6 lactose prevented binding similarly. On the other hand, the toxin also bound well to porcine gastric mucin. In this case, neutral oligosaccharides might play an important role as ligand, since galactose and lactose inhibited binding. These results suggest that the toxin is capable of recognizing a wide variety of oligosaccharide structures.

  5. Exploration of immunoglobulin transcriptomes from mice immunized with three-finger toxins and phospholipases A2 from the Central American coral snake, Micrurus nigrocinctus

    DEFF Research Database (Denmark)

    Laustsen, Andreas Hougaard; Engmark, Mikael; Clouser, Christopher

    2017-01-01

    small but potent snake venom toxins represents a challenge for obtaining a balanced immune response against the medically relevant components of the venom. Here, we employ high-throughput sequencing of the immunoglobulin (Ig) transcriptome of mice immunized with a three-finger toxin and a phospholipase...... A2 from the venom of the Central American coral snake, Micrurus nigrocinctus. Although exploratory in nature, our indicate results showed that only low frequencies of mRNA encoding IgG isotypes, the most relevant isotype for therapeutic purposes, were present in splenocytes of five mice immunized...... with 6 doses of the two types of toxins over 90 days. Furthermore, analysis of Ig heavy chain transcripts showed that no particular combination of variable (V) and joining (J) gene segments had been selected in the immunization process, as would be expected after a strong humoral immune response...

  6. Venomics profiling of Thamnodynastes strigatus unveils matrix metalloproteinases and other novel proteins recruited to the toxin arsenal of rear-fanged snakes.

    Science.gov (United States)

    Ching, Ana T C; Paes Leme, Adriana F; Zelanis, André; Rocha, Marisa M T; Furtado, Maria de Fátima D; Silva, Débora Andrade; Trugilho, Monique R O; da Rocha, Surza L G; Perales, Jonas; Ho, Paulo L; Serrano, Solange M T; Junqueira-de-Azevedo, Inácio L M

    2012-02-03

    Rear-fanged and aglyphous snakes are usually considered not dangerous to humans because of their limited capacity of injecting venom. Therefore, only a few studies have been dedicated to characterizing the venom of the largest parcel of snake fauna. Here, we investigated the venom proteome of the rear-fanged snake Thamnodynastes strigatus , in combination with a transcriptomic evaluation of the venom gland. About 60% of all transcripts code for putative venom components. A striking finding is that the most abundant type of transcript (∼47%) and also the major protein type in the venom correspond to a new kind of matrix metalloproteinase (MMP) that is unrelated to the classical snake venom metalloproteinases found in all snake families. These enzymes were recently suggested as possible venom components, and we show here that they are proteolytically active and probably recruited to venom from a MMP-9 ancestor. Other unusual proteins were suggested to be venom components: a protein related to lactadherin and an EGF repeat-containing transcript. Despite these unusual molecules, seven toxin classes commonly found in typical venomous snakes are also present in the venom. These results support the evidence that the arsenals of these snakes are very diverse and harbor new types of biologically important molecules.

  7. Snake bite.

    Science.gov (United States)

    Warrell, David A

    2010-01-02

    Snake bite is a common and frequently devastating environmental and occupational disease, especially in rural areas of tropical developing countries. Its public health importance has been largely ignored by medical science. Snake venoms are rich in protein and peptide toxins that have specificity for a wide range of tissue receptors, making them clinically challenging and scientifically fascinating, especially for drug design. Although the full burden of human suffering attributable to snake bite remains obscure, hundreds of thousands of people are known to be envenomed and tens of thousands are killed or maimed by snakes every year. Preventive efforts should be aimed towards education of affected communities to use proper footwear and to reduce the risk of contact with snakes to a minimum through understanding of snakes' behaviour. To treat envenoming, the production and clinical use of antivenom must be improved. Increased collaboration between clinicians, epidemiologists, and laboratory toxinologists should enhance the understanding and treatment of envenoming. Copyright 2010 Elsevier Ltd. All rights reserved.

  8. SNAKE VENOMICS OF Crotalus tigris: THE MINIMALIST TOXIN ARSENAL OF THE DEADLIEST NEARTIC RATTLESNAKE VENOM

    Science.gov (United States)

    CALVETE, Juan J.; PÉREZ, Alicia; LOMONTE, Bruno; SÁNCHEZ, Elda E.; SANZ, Libia

    2012-01-01

    We report the proteomic and antivenomic characterization of Crotalus tigris venom. This venom exhibits the highest lethality for mice among rattlesnakes and the simplest toxin proteome reported to date. The venom proteome of C. tigris comprises 7–8 gene products from 6 toxin families: the presynaptic β-neurotoxic heterodimeric PLA2, Mojave toxin, and two serine proteinases comprise, respectively, 66% and 27% of the C. tigris toxin arsenal, whereas a VEGF-like protein, a CRISP molecule, a medium-sized disintegrin, and 1–2 PIII-SVMPs, each represents 0.1–5% of the total venom proteome. This toxin profile really explains the systemic neuro- and myotoxic effects observed in envenomated animals. In addition, we found that venom lethality of C. tigris and other North American rattlesnake type II venoms correlates with the concentration of Mojave toxin A-subunit, supporting the view that the neurotoxic venom phenotype of crotalid type II venoms may be described as a single-allele adaptation. Our data suggest that the evolutionary trend towards neurotoxicity, which has been also reported for the South American rattlesnakes, may have resulted by paedomorphism. The ability of an experimental antivenom to effectively immunodeplete proteins from the type II venoms of C. tigris, C. horridus, C. oreganus helleri, C. scutulatus scutulatus, and S. catenatus catenatus, indicated the feasibility of generating a pan-American anti-Crotalus type II antivenom, suggested by the identification of shared evolutionary trends among South American and North American Crotalus. PMID:22181673

  9. A heteromeric Texas coral snake toxin targets acid-sensing ion channels to produce pain.

    Science.gov (United States)

    Bohlen, Christopher J; Chesler, Alexander T; Sharif-Naeini, Reza; Medzihradszky, Katalin F; Zhou, Sharleen; King, David; Sánchez, Elda E; Burlingame, Alma L; Basbaum, Allan I; Julius, David

    2011-11-16

    Natural products that elicit discomfort or pain represent invaluable tools for probing molecular mechanisms underlying pain sensation. Plant-derived irritants have predominated in this regard, but animal venoms have also evolved to avert predators by targeting neurons and receptors whose activation produces noxious sensations. As such, venoms provide a rich and varied source of small molecule and protein pharmacophores that can be exploited to characterize and manipulate key components of the pain-signalling pathway. With this in mind, here we perform an unbiased in vitro screen to identify snake venoms capable of activating somatosensory neurons. Venom from the Texas coral snake (Micrurus tener tener), whose bite produces intense and unremitting pain, excites a large cohort of sensory neurons. The purified active species (MitTx) consists of a heteromeric complex between Kunitz- and phospholipase-A2-like proteins that together function as a potent, persistent and selective agonist for acid-sensing ion channels (ASICs), showing equal or greater efficacy compared with acidic pH. MitTx is highly selective for the ASIC1 subtype at neutral pH; under more acidic conditions (pH 100-fold) proton-evoked activation of ASIC2a channels. These observations raise the possibility that ASIC channels function as coincidence detectors for extracellular protons and other, as yet unidentified, endogenous factors. Purified MitTx elicits robust pain-related behaviour in mice by activation of ASIC1 channels on capsaicin-sensitive nerve fibres. These findings reveal a mechanism whereby snake venoms produce pain, and highlight an unexpected contribution of ASIC1 channels to nociception. © 2011 Macmillan Publishers Limited. All rights reserved

  10. Protection against osteoarthritis in experimental animals by nanogold conjugated snake venom protein toxin gold nanoparticle-Naja kaouthia cytotoxin 1.

    Science.gov (United States)

    Gomes, Antony; Saha, Partha Pratim; Bhowmik, Tanmoy; Dasgupta, Anjan Kumar; Dasgupta, Subir Chandra

    2016-12-01

    Increased severity of osteoarthritis (OA) and adverse side effects of its treatment led to the search for alternative therapies. It was previously reported that snake venom protein toxin Naja kaouthia cytotoxin 1 (NKCT1) and gold nanoparticle (GNP) individually have potential against excremental arthritis. In this study, we analyzed the protective activity of GNP conjugated protein toxin NKCT1 (GNP-NKCT1) against experimental OA. Gold nanoparticle conjugation with NKCT1 (GNP-NKCT1) was done and its physiochemical properties were studied. OA was induced in male albino rats by intra-articular injection of bacterial collagenase and treatment was done with NKCT1/GNP-NKCT1/standard drug (indomethacin). Physical parameter (ankle diameter), urinary markers (hydroxyproline, glucosamine, pyridinoline, deoxypyridinoline), serum and synovial membrane pro-inflammatory markers [tumour necrosis factor-alpha (TNF-α), interleukin-1β (IL-1β), IL-17, vascular endothelial growth factor (VEGF)] and matrix metalloproteinase 1 (MMP1) were measured. Joint histopathology and scanning electron microscopy imaging of articular cartilage surface were also done. Physical parameters, urinary markers, serum and synovial membrane pro-inflammatory makers and MMP1 were increased in arthritic rats and significantly restored after GNP-NKCT1/NKCT1 treatment. Joint histopathology and scanning electron microscopy imaging of articular cartilage surface also indicated the protective effect of GNP-NKCT1 against inflammatory response and cartilage degradation in osteoarthritic rats. In this study restoration of the arthritic markers and bone degradation by GNP-NKCT1 treatment indicated the anti-osteoarthritic property of GNP-NKCT1. Further studies need to be done to confirm these findings.

  11. Protection against osteoarthritis in experimental animals by nanogold conjugated snake venom protein toxin gold nanoparticle-Naja kaouthia cytotoxin 1

    Science.gov (United States)

    Gomes, Antony; Saha, Partha Pratim; Bhowmik, Tanmoy; Dasgupta, Anjan Kumar; Dasgupta, Subir Chandra

    2016-01-01

    Background & objectives: Increased severity of osteoarthritis (OA) and adverse side effects of its treatment led to the search for alternative therapies. It was previously reported that snake venom protein toxin Naja kaouthia cytotoxin 1 (NKCT1) and gold nanoparticle (GNP) individually have potential against excremental arthritis. In this study, we analyzed the protective activity of GNP conjugated protein toxin NKCT1 (GNP-NKCT1) against experimental OA. Methods: Gold nanoparticle conjugation with NKCT1 (GNP-NKCT1) was done and its physiochemical properties were studied. OA was induced in male albino rats by intra-articular injection of bacterial collagenase and treatment was done with NKCT1/GNP-NKCT1/standard drug (indomethacin). Physical parameter (ankle diameter), urinary markers (hydroxyproline, glucosamine, pyridinoline, deoxypyridinoline), serum and synovial membrane pro-inflammatory markers [tumour necrosis factor-alpha (TNF-α), interleukin-1β (IL-1β), IL-17, vascular endothelial growth factor (VEGF)] and matrix metalloproteinase 1 (MMP1) were measured. Joint histopathology and scanning electron microscopy imaging of articular cartilage surface were also done. Results: Physical parameters, urinary markers, serum and synovial membrane pro-inflammatory makers and MMP1 were increased in arthritic rats and significantly restored after GNP-NKCT1/NKCT1 treatment. Joint histopathology and scanning electron microscopy imaging of articular cartilage surface also indicated the protective effect of GNP-NKCT1 against inflammatory response and cartilage degradation in osteoarthritic rats. Interpretation & conclusions: In this study restoration of the arthritic markers and bone degradation by GNP-NKCT1 treatment indicated the anti-osteoarthritic property of GNP-NKCT1. Further studies need to be done to confirm these findings. PMID:28474628

  12. In vivo and in vitro toxicity of nanogold conjugated snake venom protein toxin GNP-NKCT1

    Directory of Open Access Journals (Sweden)

    Partha Pratim Saha

    2014-01-01

    Full Text Available Research on nanoparticles has created interest among the biomedical scientists. Nanoparticle conjugation aims to target drug delivery, increase drug efficacy and imaging for better diagnosis. Toxicity profile of the nanoconjugated molecules has not been studied well. In this communication, the toxicity profile of snake venom cytotoxin (NKCT1, an antileukemic protein toxin, was evaluated after its conjugation with gold nanoparticle (GNP-NKCT1. Gold nanoparticle conjugation with NKCT1 was done with NaBH4 reduction method. The conjugated product GNP-NKCT1 was found less toxic than NKCT1 on isolated rat lymphocyte, mice peritoneal macrophage, in culture, which was evident from the MTT/Trypan blue assay. Peritoneal mast cell degranulation was in the order of NKCT1 > GNP-NKCT1. The in vitro cardiotoxicity and neurotoxicity were increased in case of NKCT1 than GNP-NKCT1. On isolated kidney tissue, NKCT1 released significant amount of ALP and γ-GT than GNP-NKCT1. Gold nanoconjugation with NKCT1 also reduced the lethal activity in mice. In vivo acute/sub-chronic toxicity studies in mice showed significant increase in molecular markers due to NKCT1 treatment, which was reduced by gold nanoconjugation. Histopathology study showed decreased toxic effect of NKCT1 in kidney tissue after GNP conjugation. The present study confirmed that GNP conjugation significantly decreased the toxicity profile of NKCT1. Further studies are in progress to establish the molecular mechanism of GNP induced toxicity reduction.

  13. The Snake with the Scorpion’s Sting: Novel Three-Finger Toxin Sodium Channel Activators from the Venom of the Long-Glanded Blue Coral Snake (Calliophis bivirgatus

    Directory of Open Access Journals (Sweden)

    Daryl C. Yang

    2016-10-01

    Full Text Available Millions of years of evolution have fine-tuned the ability of venom peptides to rapidly incapacitate both prey and potential predators. Toxicofera reptiles are characterized by serous-secreting mandibular or maxillary glands with heightened levels of protein expression. These glands are the core anatomical components of the toxicoferan venom system, which exists in myriad points along an evolutionary continuum. Neofunctionalisation of toxins is facilitated by positive selection at functional hotspots on the ancestral protein and venom proteins have undergone dynamic diversification in helodermatid and varanid lizards as well as advanced snakes. A spectacular point on the venom system continuum is the long-glanded blue coral snake (Calliophis bivirgatus, a specialist feeder that preys on fast moving, venomous snakes which have both a high likelihood of prey escape but also represent significant danger to the predator itself. The maxillary venom glands of C. bivirgatus extend one quarter of the snake’s body length and nestle within the rib cavity. Despite the snake’s notoriety its venom has remained largely unstudied. Here we show that the venom uniquely produces spastic paralysis, in contrast to the flaccid paralysis typically produced by neurotoxic snake venoms. The toxin responsible, which we have called calliotoxin (δ-elapitoxin-Cb1a, is a three-finger toxin (3FTx. Calliotoxin shifts the voltage-dependence of NaV1.4 activation to more hyperpolarised potentials, inhibits inactivation, and produces large ramp currents, consistent with its profound effects on contractile force in an isolated skeletal muscle preparation. Voltage-gated sodium channels (NaV are a particularly attractive pharmacological target as they are involved in almost all physiological processes including action potential generation and conduction. Accordingly, venom peptides that interfere with NaV function provide a key defensive and predatory advantage to a range of

  14. The Snake with the Scorpion’s Sting: Novel Three-Finger Toxin Sodium Channel Activators from the Venom of the Long-Glanded Blue Coral Snake (Calliophis bivirgatus)

    Science.gov (United States)

    Yang, Daryl C.; Deuis, Jennifer R.; Dashevsky, Daniel; Dobson, James; Jackson, Timothy N. W.; Brust, Andreas; Xie, Bing; Koludarov, Ivan; Debono, Jordan; Hendrikx, Iwan; Hodgson, Wayne C.; Josh, Peter; Nouwens, Amanda; Baillie, Gregory J.; Bruxner, Timothy J. C.; Alewood, Paul F.; Lim, Kelvin Kok Peng; Frank, Nathaniel; Vetter, Irina; Fry, Bryan G.

    2016-01-01

    Millions of years of evolution have fine-tuned the ability of venom peptides to rapidly incapacitate both prey and potential predators. Toxicofera reptiles are characterized by serous-secreting mandibular or maxillary glands with heightened levels of protein expression. These glands are the core anatomical components of the toxicoferan venom system, which exists in myriad points along an evolutionary continuum. Neofunctionalisation of toxins is facilitated by positive selection at functional hotspots on the ancestral protein and venom proteins have undergone dynamic diversification in helodermatid and varanid lizards as well as advanced snakes. A spectacular point on the venom system continuum is the long-glanded blue coral snake (Calliophis bivirgatus), a specialist feeder that preys on fast moving, venomous snakes which have both a high likelihood of prey escape but also represent significant danger to the predator itself. The maxillary venom glands of C. bivirgatus extend one quarter of the snake’s body length and nestle within the rib cavity. Despite the snake’s notoriety its venom has remained largely unstudied. Here we show that the venom uniquely produces spastic paralysis, in contrast to the flaccid paralysis typically produced by neurotoxic snake venoms. The toxin responsible, which we have called calliotoxin (δ-elapitoxin-Cb1a), is a three-finger toxin (3FTx). Calliotoxin shifts the voltage-dependence of NaV1.4 activation to more hyperpolarised potentials, inhibits inactivation, and produces large ramp currents, consistent with its profound effects on contractile force in an isolated skeletal muscle preparation. Voltage-gated sodium channels (NaV) are a particularly attractive pharmacological target as they are involved in almost all physiological processes including action potential generation and conduction. Accordingly, venom peptides that interfere with NaV function provide a key defensive and predatory advantage to a range of invertebrate

  15. Bordetella dermonecrotic toxin binds to target cells via the N-terminal 30 amino acids.

    Science.gov (United States)

    Fukui-Miyazaki, Aya; Ohnishi, Shinya; Kamitani, Shigeki; Abe, Hiroyuki; Horiguchi, Yasuhiko

    2011-03-01

    Bordetella dermonecrotic toxin (DNT) affects the biological function of host cells by activating intracellular Rho GTPases. The toxin binds to unidentified receptor(s) via 54 N-terminal amino acids, undergoes intramolecular cleavage on the C-terminal side of Arg(44) by furin or furin-like protease, and eventually enters the cytoplasm where the Rho GTPases reside. The binding to the receptor(s) and intramolecular cleavage are essential for DNT to intoxicate cells, and the 54 amino-acid binding domain encompasses the cleavage site, however, it is unclear whether these two events are related. In this study, we could narrow down the cell-binding domain to the N-terminal amino acids 2-30. The region does not contain the furin-recognition site, indicating that the cell binding and the intramolecular cleavage are independent events. © 2011 The Societies and Blackwell Publishing Asia Pty Ltd.

  16. Changes in protease activity and Cry3Aa toxin binding in the Colorado potato beetle: implications for insect resistance to Bacillus thuringiensis toxins

    Science.gov (United States)

    Olga Loseva; Mohamed Ibrahim; Mehmet Candas; C. Noah Koller; Leah S. Bauer; Lee A. Jr. Bulla

    2002-01-01

    Widespread commercial use of Bacillus thuringiensis Cry toxins to control pest insects has increased the likelihood for development of insect resistance to this entomopathogen. In this study, we investigated protease activity profiles and toxin-binding capacities in the midgut of a strain of Colorado potato beetle (CPB) that has developed resistance...

  17. Polyamines as Snake Toxins and Their Probable Pharmacological Functions in Envenomation

    Directory of Open Access Journals (Sweden)

    Steven D. Aird

    2016-09-01

    Full Text Available While decades of research have focused on snake venom proteins, far less attention has been paid to small organic venom constituents. Using mostly pooled samples, we surveyed 31 venoms (six elapid, six viperid, and 19 crotalid for spermine, spermidine, putrescine, and cadaverine. Most venoms contained all four polyamines, although some in essentially trace quantities. Spermine is a potentially significant component of many viperid and crotalid venoms (≤0.16% by mass, or 7.9 µmol/g; however, it is almost completely absent from elapid venoms assayed. All elapid venoms contained larger molar quantities of putrescine and cadaverine than spermine, but still at levels that are likely to be biologically insignificant. As with venom purines, polyamines impact numerous physiological targets in ways that are consistent with the objectives of prey envenomation, prey immobilization via hypotension and paralysis. Most venoms probably do not contain sufficient quantities of polyamines to induce systemic effects in prey; however, local effects seem probable. A review of the pharmacological literature suggests that spermine could contribute to prey hypotension and paralysis by interacting with N-methyl-d-aspartate (NMDA and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA receptors, nicotinic and muscarinic acetylcholine receptors, γ-Aminobutyric acid (GABA receptors, blood platelets, ryanodine receptors, and Ca2+-ATPase. It also blocks many types of cation-permeable channels by interacting with negatively charged amino acid residues in the channel mouths. The site of envenomation probably determines which physiological targets assume the greatest importance; however, venom-induced liberation of endogenous, intracellular stores of polyamines could potentially have systemic implications and may contribute significantly to envenomation sequelae.

  18. Identification of a Bacillus thuringiensis Cry11Ba toxin-binding aminopeptidase from the mosquito, Anopheles quadrimaculatus

    OpenAIRE

    Abdullah Mohd; Valaitis Algimantas P; Dean Donald H

    2006-01-01

    Abstract Background Aminopeptidase N (APN) type proteins isolated from several species of lepidopteran insects have been implicated as Bacillus thuringiensis (Bt) toxin-binding proteins (receptors) for Cry toxins. We examined brush border membrane vesicle (BBMV) proteins from the mosquito Anopheles quadrimaculatus to determine if APNs from this organism would bind mosquitocidal Cry toxins that are active to it. Results A 100-kDa protein with APN activity (APNAnq 100) was isolated from the bru...

  19. Metal ions mediate the binding of cyanobacterial toxins to human protein phosphatase I:a computational study

    OpenAIRE

    Mattila, K. (Kimmo); Annila, A. (Arto); Rantala, T. T. (Tapio T.)

    2000-01-01

    Abstract The binding mechanisms of two cyanobacterial toxins, Microcystin-LR and Nodularin, to Protein Phosphatase 1 (PP1) were studied with molecular modeling and molecular dynamics simulations. The models of the two toxin-phosphatase complexes are based on the structure of PP1-microcystin complex determined by X-ray crystallography, and on the conformation of nodularin in water determined by NMR. The binding site of PP1 including the ligated toxin and the surrounding ...

  20. Localization of Bacillus thuringiensis Cry1A toxin-binding molecules in gypsy moth larval gut sections using fluorescence microscopy

    Science.gov (United States)

    Algimantas P. Valaitis

    2011-01-01

    The microbial insecticide Bacillus thuringiensis (Bt) produces Cry toxins, proteins that bind to the brush border membranes of gut epithelial cells of insects that ingest it, disrupting the integrity of the membranes, and leading to cell lysis and insect death. In gypsy moth, Lymantria dispar, two toxin-binding molecules for the...

  1. Altered binding of the Cry1Ac toxin to larval membranes but not to the toxin-binding protein in Plodia interpunctella selected for resistance to different Bacillus thuringiensis isolates.

    Science.gov (United States)

    Mohammed, S I; Johnson, D E; Aronson, A I

    1996-11-01

    Immunoblotting and cytochemical procedures were used to determine whether toxin binding was altered in strains of the Indianmeal moth, Plodia interpunctella, selected for resistance to various strains of Bacillus thuringiensis. Each of these B. thuringiensis subspecies produces a mixture of protoxins, primarily Cry1 types, and the greatest insect resistance is to the Cry1A protoxins. In several cases, however, there was also resistance to toxins not present in the B. thuringiensis strains used for selection. The Cry1Ab and Cry1Ac toxins bound equally well over a range of toxin concentrations and times of incubation to a single protein of ca. 80-kDa in immunoblots of larval membrane extracts from all of the colonies. This binding protein is essential for toxicity since a mutant Cry1Ac toxin known to be defective in binding and thus less toxic bound poorly to the 80-kDa protein. This binding protein differed in size from the major aminopeptidase N antigens implicated in toxin binding in other insects. Binding of fluorescently labeled Cry1Ac or Cry1Ab toxin to larval sections was found at the tips of the brush border membrane prepared from the susceptible but not from any of the resistant P. interpunctella. Accessibility of a major Cry1A-binding protein appears to be altered in resistant larvae and could account for their broad resistance to several B. thuringiensis toxins.

  2. Is there more than one way to skin a newt? Convergent toxin resistance in snakes is not due to a common genetic mechanism.

    Science.gov (United States)

    Feldman, C R; Durso, A M; Hanifin, C T; Pfrender, M E; Ducey, P K; Stokes, A N; Barnett, K E; Brodie, E D; Brodie, E D

    2016-01-01

    Convergent evolution of tetrodotoxin (TTX) resistance, at both the phenotypic and genetic levels, characterizes coevolutionary arms races between amphibians and their snake predators around the world, and reveals remarkable predictability in the process of adaptation. Here we examine the repeatability of the evolution of TTX resistance in an undescribed predator-prey relationship between TTX-bearing Eastern Newts (Notophthalmus viridescens) and Eastern Hog-nosed Snakes (Heterodon platirhinos). We found that that local newts contain levels of TTX dangerous enough to dissuade most predators, and that Eastern Hog-nosed Snakes within newt range are highly resistant to TTX. In fact, these populations of Eastern Hog-nosed Snakes are so resistant to TTX that the potential for current reciprocal selection might be limited. Unlike all other cases of TTX resistance in vertebrates, H. platirhinos lacks the adaptive amino acid substitutions in the skeletal muscle sodium channel that reduce TTX binding, suggesting that physiological resistance in Eastern Hog-nosed Snakes is conferred by an alternate genetic mechanism. Thus, phenotypic convergence in this case is not due to parallel molecular evolution, indicating that there may be more than one way for this adaptation to arise, even among closely related species.

  3. Characterization of a new muscarinic toxin from the venom of the Brazilian coral snake Micrurus lemniscatus in rat hippocampus.

    Science.gov (United States)

    da Silva, Daniel Coelho; de Medeiros, Wyara Aparecida Araújo; Batista, Isabel de Fátima Correia; Pimenta, Daniel Carvalho; Lebrun, Ivo; Abdalla, Fernando Maurício Francis; Sandoval, Maria Regina Lopes

    2011-12-19

    We have isolated a new muscarinic protein (MT-Mlα) from the venom of the Brazilian coral snake Micrurus lemniscatus. This small protein, which had a molecular mass of 7,048Da, shared high sequence homology with three-finger proteins that act on cholinergic receptors. The first 12 amino acid residues of the N-terminal sequence were determined to be: Leu-Ile-Cys-Phe-Ile-Cys-Phe-Ser-Pro-Thr-Ala-His. The MT-Mlα was able to displace the [(3)H]QNB binding in the hippocampus of rats. The binding curve in competition experiments with MT-Mlα was indicative of two types of [(3)H]QNB-binding site with pK(i) values of 9.08±0.67 and 6.17±0.19, n=4, suggesting that various muscarinic acetylcholine receptor (mAChR) subtypes may be the target proteins of MT-Mlα. The MT-Mlα and the M(1) antagonist pirenzepine caused a dose-dependent block on total [(3)H]inositol phosphate accumulation induced by carbachol. The IC(50) values for MT-Mlα and pirenzepine were, respectively, 33.1 and 2.26 nM. Taken together, these studies indicate that the MT-Mlα has antagonist effect on mAChRs in rat hippocampus. The results of the present study show, for the first time, that mAChRs function is drastically affected by MT-Mlα since it not only has affinity for mAChRs but also has the ability to inhibit mAChRs. Copyright © 2011 Elsevier Inc. All rights reserved.

  4. Toxin-binding treatment for Clostridium difficile: a review including reports of studies with tolevamer.

    Science.gov (United States)

    Weiss, Karl

    2009-01-01

    Clostridium difficile represents an increasing threat to patients, mainly as a hospital-acquired infection causing antibiotic-associated colitis (AAC). The emergence of a new more virulent strain in North America and Europe has been linked to increased morbidity and mortality. For a long period of time the only available therapeutic options were oral vancomycin and metronidazole. However, both of these antibiotics have limitations either in terms of efficacy, cost, formulation, side effects or the risk of emerging antibiotic resistance among enterococci. Clostridium difficile produces two powerful toxins (A and B) that are responsible for the entire clinical spectrum associated with AAC. As this is exclusively a toxin-mediated disease, agents with the potential of binding these targets have been tested. Data on polymer-based toxin-binding agents such as cholestyramine, Synsorb 90 and tolevamer, designed to target specific bacterial toxins, will be reviewed. Bovine colostrum and specific human monoclonal antibodies aimed at neutralising toxin A, although still at an early stage of development, are also new avenues to be explored. Non-antibiotic-based therapies might become the best available option for a condition almost always caused by antibiotics.

  5. Molecular Conversion of Muscarinic Acetylcholine Receptor M5 to Muscarinic Toxin 7 (MT7-Binding Protein

    Directory of Open Access Journals (Sweden)

    Katja Näreoja

    2011-11-01

    Full Text Available Muscarinic toxin 7 (MT7 is a mamba venom peptide that binds selectively to the M1 muscarinic acetylcholine receptor. We have previously shown that the second (ECL2 and third (ECL3 extracellular loops of the M1 receptor are critically involved in binding the peptide. In this study we used a mutagenesis approach on the M5 subtype of the receptor family to find out if this possesses a similar structural architecture in terms of toxin binding as the M1 receptor. An M5 receptor construct (M5-E175Y184E474, mutated at the formerly deciphered critical residues on ECL2 and 3, gained the ability to bind MT7, but with rather low affinity as determined in a functional assay (apparent Ki = 24 nM; apparent Ki for M1 = 0.5 nM. After screening for different domains and residues, we found a specific residue (P179 to L in M5 in the middle portion of ECL2 that was necessary for high affinity binding of MT7 (M5-EL179YE, apparent Ki = 0.5 nM. Mutation of P179 to A confirmed a role for the leucine side chain in the binding of MT7. Together the results reveal new binding interactions between receptors and the MT7 peptide and strengthen the hypothesis that ECL2 sequence is of utmost importance for MT binding to muscarinic receptors.

  6. Snake venom toxins. The amino acid sequences of two toxins (CM-2a and CM-3) from Naja haje annulifera (Egyptian cobra) venom.

    Science.gov (United States)

    Joubert, F J

    1977-03-01

    Two toxins, CM-2a and CM-3, were purified from the venom of Naja haje annulifera by gel filtration on Sephadex G-50 and by ion-exchange chromatography on CM-cellulose. Whereas toxin CM-2a contains 61 amino acid residues, toxin CM-3 comprises 60 residues. Both toxins are cross-linked by four intra-chain disulphide bridges. The complete amino acid sequences of the toxins have been elucidated. The properties of the toxins were compared with those of a cytotoxin, a short neurotoxin, a long neurotoxin and an angusticeps type. The sequences of toxin CM-2a and CM-3 and some of the invariant residues do not show a high degree of similarity with those of the other toxins. The toxicities of toxins CM-2a and CM-3 are much lower than those encountered for the cytotoxin or the neurotoxins and their immunochemical properties are distinct from both the cytotoxin and the neurotoxins. They probably represent a new class of toxins.

  7. Snake venom toxins. The amino-acid sequences of three toxins (CM-8, CM-11 and CM-13a) from Naja haje annulifera (Egyptian cobra) venom.

    Science.gov (United States)

    Joubert, F J

    1976-04-15

    Three toxins (CM-8, CM-11, and CM-13a) were purified from the venom of Naja haje annulifera by gel filtration on Sephadex G-50 and by ion-exchange chromatography on CM-cellulose. Whereas toxin CM-8 and CM-11 comprise 60 amino acid residues, toxin CM-13a contains 61 residues. All three toxins are cross-linked by four intrachain disulphide bridges. The complete amino acid sequences of these toxins have been elucidated. The reduced and S-carboxymethylated toxins were digested with trypsin and chymotrypsin and the peptides purified by ion-exchange chromatography, gel filtration and chromatography or electrophoresis on paper. The Edman procedure, either through the use of the automatic sequencer or by manual manipulation, was employed to obtain the sequence of the intact toxins and the pure peptides. The chymotryptic digests provided the necessary overlapping peptides which allowed the alignment of the tryptic peptides. The properties of the three toxins were compared with those of the cytotoxin group. The toxicities the serological properties, the sequences and the invariant amino acid residues of toxin CM-8 and CM-11 resemble the corresponding properties of the cytotoxin group. The sequence and serological properties of toxin CM-13a show that it is related to the cytotoxin group, but its toxicity is much lower than those encountered in the cytotoxin group.

  8. Mipartoxin-I, a novel three-finger toxin, is the major neurotoxic component in the venom of the redtail coral snake Micrurus mipartitus (Elapidae).

    Science.gov (United States)

    Rey-Suárez, Paola; Floriano, Rafael Stuani; Rostelato-Ferreira, Sandro; Saldarriaga-Córdoba, Mónica; Núñez, Vitelbina; Rodrigues-Simioni, Léa; Lomonte, Bruno

    2012-10-01

    The major venom component of Micrurus mipartitus, a coral snake distributed from Nicaragua to northern South America, was characterized biochemically and functionally. This protein, named mipartoxin-I, is a novel member of the three-finger toxin superfamily, presenting the characteristic cysteine signature and amino acid sequence length of the short-chain, type-I, α-neurotoxins. Nevertheless, it varies considerably from related toxins, with a sequence identity not higher than 70% in a multiple alignment of 67 proteins within this family. Its observed molecular mass (7030.0) matches the value predicted by its amino acid sequence, indicating lack of post-translational modifications. Mipartoxin-I showed a potent lethal effect in mice (intraperitoneal median lethal dose: 0.06 μg/g body weight), and caused a clear neuromuscular blockade on both avian and mouse nerve-muscle preparations, presenting a post-synaptic action through the cholinergic nicotinic receptor. Since mipartoxin-I is the most abundant (28%) protein in M. mipartitus venom, it should play a major role in its toxicity, and therefore represents an important target for developing a therapeutic antivenom, which is very scarce or even unavailable in the regions where this snake inhabits. The structural information here provided might help in the preparation of a synthetic or recombinant immunogen to overcome the limited venom availability. Copyright © 2012 Elsevier Ltd. All rights reserved.

  9. Binding of fluorescently labeled cholera toxin subunit B to glycolipids in the human submandibular gland and inhibition of binding by periodate oxidation and by galactose

    DEFF Research Database (Denmark)

    Kirkeby, S

    2016-01-01

    FITC-labeled cholera toxin subunit B (CTB) stained the surfaces of cells of mucous acini in the submandibular gland. CTB, also called choleragenoid, binds to the GM1 glycolipid in the cell membrane. The binding in most acini was inhibited by periodic acid oxidation of the sections, while some acini...... to the internal galactose residue linked to GalNAc, as in the GM1 glycolipid. Inhibition of the GM1 receptor binding to cholera toxin has potential for protection of humans against cholera. Galactose and agents that modify sialic acid inhibit the accessibility of the toxin to the GM1 carbohydrate receptor. Human...

  10. Identification of a Bacillus thuringiensis Cry11Ba toxin-binding aminopeptidase from the mosquito, Anopheles quadrimaculatus.

    Science.gov (United States)

    Abdullah, Mohd Amir F; Valaitis, Algimantas P; Dean, Donald H

    2006-05-22

    Aminopeptidase N (APN) type proteins isolated from several species of lepidopteran insects have been implicated as Bacillus thuringiensis (Bt) toxin-binding proteins (receptors) for Cry toxins. We examined brush border membrane vesicle (BBMV) proteins from the mosquito Anopheles quadrimaculatus to determine if APNs from this organism would bind mosquitocidal Cry toxins that are active to it. A 100-kDa protein with APN activity (APNAnq 100) was isolated from the brush border membrane of Anopheles quadrimaculatus. Native state binding analysis by surface plasmon resonance shows that APNAnq 100 forms tight binding to a mosquitocidal Bt toxin, Cry11Ba, but not to Cry2Aa, Cry4Ba or Cry11Aa. An aminopeptidase from Anopheles quadrimaculatus mosquitoes is a specific binding protein for Bacillus thuringiensis Cry11Ba.

  11. Identification of a Bacillus thuringiensis Cry11Ba toxin-binding aminopeptidase from the mosquito, Anopheles quadrimaculatus

    Directory of Open Access Journals (Sweden)

    Abdullah Mohd

    2006-05-01

    Full Text Available Abstract Background Aminopeptidase N (APN type proteins isolated from several species of lepidopteran insects have been implicated as Bacillus thuringiensis (Bt toxin-binding proteins (receptors for Cry toxins. We examined brush border membrane vesicle (BBMV proteins from the mosquito Anopheles quadrimaculatus to determine if APNs from this organism would bind mosquitocidal Cry toxins that are active to it. Results A 100-kDa protein with APN activity (APNAnq 100 was isolated from the brush border membrane of Anopheles quadrimaculatus. Native state binding analysis by surface plasmon resonance shows that APNAnq 100 forms tight binding to a mosquitocidal Bt toxin, Cry11Ba, but not to Cry2Aa, Cry4Ba or Cry11Aa. Conclusion An aminopeptidase from Anopheles quadrimaculatus mosquitoes is a specific binding protein for Bacillus thuringiensis Cry11Ba.

  12. Characterization of a human coagulation factor Xa-binding site on Viperidae snake venom phospholipases A2 by affinity binding studies and molecular bioinformatics

    Directory of Open Access Journals (Sweden)

    Gowda Veerabasappa T

    2007-12-01

    Full Text Available Abstract Background The snake venom group IIA secreted phospholipases A2 (SVPLA2, present in the Viperidae snake family exhibit a wide range of toxic and pharmacological effects. They exert their different functions by catalyzing the hydrolysis of phospholipids (PL at the membrane/water interface and by highly specific direct binding to: (i presynaptic membrane-bound or intracellular receptors; (ii natural PLA2-inhibitors from snake serum; and (iii coagulation factors present in human blood. Results Using surface plasmon resonance (SPR protein-protein interaction measurements and an in vitro biological test of inhibition of prothrombinase activity, we identify a number of Viperidae venom SVPLA2s that inhibit blood coagulation through direct binding to human blood coagulation factor Xa (FXa via a non-catalytic, PL-independent mechanism. We classify the SVPLA2s in four groups, depending on the strength of their binding. Molecular electrostatic potentials calculated at the surface of 3D homology-modeling models show a correlation with inhibition of prothrombinase activity. In addition, molecular docking simulations between SVPLA2 and FXa guided by the experimental data identify the potential FXa binding site on the SVPLA2s. This site is composed of the following regions: helices A and B, the Ca2+ loop, the helix C-β-wing loop, and the C-terminal fragment. Some of the SVPLA2 binding site residues belong also to the interfacial binding site (IBS. The interface in FXa involves both, the light and heavy chains. Conclusion We have experimentally identified several strong FXa-binding SVPLA2s that disrupt the function of the coagulation cascade by interacting with FXa by the non-catalytic PL-independent mechanism. By theoretical methods we mapped the interaction sites on both, the SVPLA2s and FXa. Our findings may lead to the design of novel, non-competitive FXa inhibitors.

  13. Characterization of a human coagulation factor Xa-binding site on Viperidae snake venom phospholipases A2 by affinity binding studies and molecular bioinformatics.

    Science.gov (United States)

    Faure, Grazyna; Gowda, Veerabasappa T; Maroun, Rachid C

    2007-12-06

    The snake venom group IIA secreted phospholipases A2 (SVPLA2), present in the Viperidae snake family exhibit a wide range of toxic and pharmacological effects. They exert their different functions by catalyzing the hydrolysis of phospholipids (PL) at the membrane/water interface and by highly specific direct binding to: (i) presynaptic membrane-bound or intracellular receptors; (ii) natural PLA2-inhibitors from snake serum; and (iii) coagulation factors present in human blood. Using surface plasmon resonance (SPR) protein-protein interaction measurements and an in vitro biological test of inhibition of prothrombinase activity, we identify a number of Viperidae venom SVPLA2s that inhibit blood coagulation through direct binding to human blood coagulation factor Xa (FXa) via a non-catalytic, PL-independent mechanism. We classify the SVPLA2s in four groups, depending on the strength of their binding. Molecular electrostatic potentials calculated at the surface of 3D homology-modeling models show a correlation with inhibition of prothrombinase activity. In addition, molecular docking simulations between SVPLA2 and FXa guided by the experimental data identify the potential FXa binding site on the SVPLA2s. This site is composed of the following regions: helices A and B, the Ca2+ loop, the helix C-beta-wing loop, and the C-terminal fragment. Some of the SVPLA2 binding site residues belong also to the interfacial binding site (IBS). The interface in FXa involves both, the light and heavy chains. We have experimentally identified several strong FXa-binding SVPLA2s that disrupt the function of the coagulation cascade by interacting with FXa by the non-catalytic PL-independent mechanism. By theoretical methods we mapped the interaction sites on both, the SVPLA2s and FXa. Our findings may lead to the design of novel, non-competitive FXa inhibitors.

  14. Clostridium Perfringens Epsilon Toxin Binds to Membrane Lipids and Its Cytotoxic Action Depends on Sulfatide.

    Directory of Open Access Journals (Sweden)

    Carles Gil

    Full Text Available Epsilon toxin (Etx is one of the major lethal toxins produced by Clostridium perfringens types B and D, being the causal agent of fatal enterotoxemia in animals, mainly sheep and goats. Etx is synthesized as a non-active prototoxin form (proEtx that becomes active upon proteolytic activation. Etx exhibits a cytotoxic effect through the formation of a pore in the plasma membrane of selected cell targets where Etx specifically binds due to the presence of specific receptors. However, the identity and nature of host receptors of Etx remain a matter of controversy. In the present study, the interactions between Etx and membrane lipids from the synaptosome-enriched fraction from rat brain (P2 fraction and MDCK cell plasma membrane preparations were analyzed. Our findings show that both Etx and proEtx bind to lipids extracted from lipid rafts from the two different models as assessed by protein-lipid overlay assay. Lipid rafts are membrane microdomains enriched in cholesterol and sphingolipids. Binding of proEtx to sulfatide, phosphatidylserine, phosphatidylinositol (3-phosphate and phosphatidylinositol (5-phosphate was detected. Removal of the sulphate groups via sulfatase treatment led to a dramatic decrease in Etx-induced cytotoxicity, but not in proEtx-GFP binding to MDCK cells or a significant shift in oligomer formation, pointing to a role of sulfatide in pore formation in rafts but not in toxin binding to the target cell membrane. These results show for the first time the interaction between Etx and membrane lipids from host tissue and point to a major role for sulfatides in C. perfringens epsilon toxin pathophysiology.

  15. Snake venom toxin. The amino acid sequence of three toxins (CM-2h, CM-4b and CM-6) from Naja haje annulifera (Egyptian cobra) venom.

    Science.gov (United States)

    Joubert, F J

    1977-01-01

    Three toxins CM-2h, CM-4b and CM-6 were purified from the venom of Naja haje annulifera by gel filtration on Sephadex and by ion-exchange chromatography on CM-cellulose. They comprise 60 amino acid residues and are cross-linked by four intrachain disulphide bridges. The complete amino acid sequences of the three toxins have been elucidated. The toxicities, the serological properties, the sequences and the invariant amino acid residues of toxin CM-2h, CM-4b and CM-6 resemble the corresponding properties of the cytotoxin group.

  16. Snake venom toxins. The amino acid sequence of three toxins (CM-2e, CM-4a and CM-) from Naja haje annulifera (Egyptian cobra) venom.

    Science.gov (United States)

    Joubert, F J

    1976-12-01

    Three toxins (CM-2e, CM-4a and CM-7) were purified from the venom of Naja haje annulifera by gel filtration on Sephadex and by ion-exchange chromatography on CM-cellulose. They comprise 60 amino acid residues and are cross-linked by four intrachain disulphide bridges. The complete amino acid sequences of the three toxins have been elucidated. The toxicities, the serological properties, the sequences and the invariant amino acid residues of toxin CM-2e, CM-4a and CM-7 resemble the corresponding properties of the cytotoxin group.

  17. Use of immunoturbidimetry to detect venom-antivenom binding using snake venoms.

    Science.gov (United States)

    O'Leary, M A; Maduwage, K; Isbister, G K

    2013-01-01

    Immunoturbidimetry studies the phenomenon of immunoprecipitation of antigens and antibodies in solution, where there is the formation of large, polymeric insoluble immunocomplexes that increase the turbidity of the solution. We used immunoturbidimetry to investigate the interaction between commercial snake antivenoms and snake venoms, as well as cross-reactivity between different snake venoms. Serial dilutions of commercial snake antivenoms (100μl) in water were placed in the wells of a microtitre plate and 100μl of a venom solution (50μg/ml in water) was added. Absorbance readings were taken at 340nm every minute on a BioTek ELx808 plate reader at 37°C. Limits imposed were a 30minute cut-off and 0.004 as the lowest significant maximum increase. Reactions with rabbit antibodies were carried out similarly, except that antibody dilutions were in PBS. Mixing venom and antivenom/antibodies resulted in an immediate increase in turbidity, which either reached a maximum or continued to increase until a 30minute cut-off. There was a peak in absorbance readings for most Australian snake venoms mixed with the corresponding commercial antivenom, except for Pseudonaja textilis venom and brown snake antivenom. There was cross-reactivity between Naja naja venom from Sri Lanka and tiger snake antivenom indicated by turbidity when they were mixed. Mixing rabbit anti-snake antibodies with snake venoms resulted in increasing turbidity, but there was not a peak suggesting the antibodies were not sufficiently concentrated. The absorbance reading at pre-determined concentrations of rabbit antibodies mixed with different venoms was able to quantify the cross-reactivity between venoms. Indian antivenoms from two manufacturers were tested against four Sri Lankan snake venoms (Daboia russelli, N. naja, Echis carinatus and Bungarus caeruleus) and showed limited formation of immunocomplexes with antivenom from one manufacturer. The turbidity test provides an easy and rapid way to compare

  18. In vitro study of the effectiveness of three commercial adsorbents for binding oleander toxins.

    Science.gov (United States)

    Tiwary, Asheesh K; Poppenga, Robert H; Puschner, Birgit

    2009-03-01

    Oleander (Nerium oleander) poisoning is a common problem found in many parts of the world. The oleander toxicity is due to oleandrin and its aglycone metabolite oleandrigenin. Activated charcoal is a useful gastrointestinal decontamination agent that limits the absorption of ingested toxins. A relatively new clay product, Bio-Sponge, containing di-tri-octahedral smectite as the active ingredient, is also recommended for adsorbing bacterial toxins in the gastrointestinal tract. Bio-Sponge has been used to prevent gastrointestinal absorption of oleander toxins in livestock but the efficacy of activated charcoal and Bio-Sponge for adsorbing oleandrin and oleandrigenin has not yet been studied. An in vitro experiment to compare the efficacy of three commercially available adsorbents was performed. The adsorbents include Bio-Sponge, ToxiBan granules, and a generic grade activated charcoal. ToxiBan granules have the highest adsorptive capacity, followed by the generic grade activated charcoal, and finally, Bio-Sponge. Bio-Sponge did not adsorb oleandrin and oleandrigenin at concentrations that are expected to be present in the gastrointestinal tract of poisoned animals. On the basis of this in vitro study, products containing activated charcoal are more effective for binding oleander toxins and providing gastrointestinal decontamination than products containing di-tri-octahedral smectite. However, the ability of these adsorbents to alter the clinical outcome in oleander-poisoned animals or humans is yet to be evaluated.

  19. Radioactive labelling of toxin I from Anemonia sulcata and binding to crayfish nerve in vitro.

    Science.gov (United States)

    Stengelin, S; Hucho, F

    1980-04-01

    1. Radioactive derivatives of neurotoxin I (ATX I) from Anemonia sulcata have been synthesized: Iodination of ATX I with 125I yielded a mixture of reaction products from which monoiodo and diiodo ATX I were isolated. 2. 125I-ATX I was shown to bind to the axonal membrane from Astacus leptodactylus main walking nerve. Specificity of binding was shown by saturability of the binding sites and by competitive binding of native and radioactive toxin. 3. Astacus nerve bound 44 fmol of 125I-ATX I/mg nerve (wet weight). The axonal membrane surface of the nerve was determined to be 7800 cm2/g nerve. This amounts to a binding site density of around 35/mu2 axonal surface. Binding was not inhibited by tetrodotoxin, the blocker of the selectivity filter of voltage-dependent sodium channels. 125I-ATX I therefore may bind to the sodium channel-inactivating gate. 4. The affinity of the nerve membrane receptors for 125I-ATX I appears to be voltage-dependent: KD = 5 nM was found with whole crayfish nerves in the presence of tetrodotoxin, KD = 40nM in the absence of tetrodotoxin and an even lower affinity was obtained with axonal membrane fragments isolated from the nerve. Drugs destabilizing the membrane potential, e.g. veratridine, ouabain and sodium azide lowered the affinity or abolished binding completely.

  20. Novel Catalytically-Inactive PII Metalloproteinases from a Viperid Snake Venom with Substitutions in the Canonical Zinc-Binding Motif.

    Science.gov (United States)

    Camacho, Erika; Sanz, Libia; Escalante, Teresa; Pérez, Alicia; Villalta, Fabián; Lomonte, Bruno; Neves-Ferreira, Ana Gisele C; Feoli, Andrés; Calvete, Juan J; Gutiérrez, José María; Rucavado, Alexandra

    2016-10-12

    Snake venom metalloproteinases (SVMPs) play key biological roles in prey immobilization and digestion. The majority of these activities depend on the hydrolysis of relevant protein substrates in the tissues. Hereby, we describe several isoforms and a cDNA clone sequence, corresponding to PII SVMP homologues from the venom of the Central American pit viper Bothriechis lateralis, which have modifications in the residues of the canonical sequence of the zinc-binding motif HEXXHXXGXXH. As a consequence, the proteolytic activity of the isolated proteins was undetectable when tested on azocasein and gelatin. These PII isoforms comprise metalloproteinase and disintegrin domains in the mature protein, thus belonging to the subclass PIIb of SVMPs. PII SVMP homologues were devoid of hemorrhagic and in vitro coagulant activities, effects attributed to the enzymatic activity of SVMPs, but induced a mild edema. One of the isoforms presents the characteristic RGD sequence in the disintegrin domain and inhibits ADP- and collagen-induced platelet aggregation. Catalytically-inactive SVMP homologues may have been hitherto missed in the characterization of snake venoms. The presence of such enzymatically-inactive homologues in snake venoms and their possible toxic and adaptive roles deserve further investigation.

  1. Binding of Bacillus thuringiensis Cry1A toxins with brush border membrane vesicles of maize stem borer (Chilo partellus Swinhoe).

    Science.gov (United States)

    Sharma, Priyanka; Nain, Vikrant; Lakhanpaul, Suman; Kumar, P A

    2011-02-01

    Maize stem borer (Chilo partellus) is a major insect pest of maize and sorghum in Asia and Africa. Bacillus thuringiensis (Bt) δ-endotoxins have been found effective against C. partellus, both in diet-overlay assay and in transgenic plants. Gene stacking as one of the resistance management strategies in Bt maize requires an understanding of receptor sharing and binding affinity of δ-endotoxins. In the present study, binding affinity of three fluorescein isothiocyanate labeled Cry1A toxins showed high correlation with the toxicity of respective δ-endotoxins. Competitive binding studies showed that Cry1Ab toxins share some of the binding sites with Cry1Aa and Cry1Ac with low affinity and that Cry1Ab may have additional binding sites that are unavailable to the other two toxins tested. Copyright © 2010 Elsevier Inc. All rights reserved.

  2. Inhibitory effect of snake venom toxin on NF-κB activity prevents human cervical cancer cell growth via increase of death receptor 3 and 5 expression.

    Science.gov (United States)

    Lee, Hye Lim; Park, Mi Hee; Hong, Ji Eun; Kim, Dae Hwan; Kim, Ji Young; Seo, Hyen Ok; Han, Sang-Bae; Yoon, Joo Hee; Lee, Won Hyoung; Song, Ho Sueb; Lee, Ji In; Lee, Ung Soo; Song, Min Jong; Hong, Jin Tae

    2016-02-01

    We previously found that snake venom toxin inhibits nuclear factor kappa B (NF-κB) activity in several cancer cells. NF-κB is implicated in cancer cell growth and chemoresistance. In our present study, we investigated whether snake venom toxin (SVT) inhibits NF-κB, thereby preventing human cervical cancer cell growth (Ca Ski and C33A). SVT (0-12 μg/ml) inhibited the growth of cervical cancer cells by the induction of apoptotic cell death. These inhibitory effects were associated with the inhibition of NF-κB activity. However, SVT dose dependently increased the expression of death receptors (DRs): DR3, DR5 and DR downstream pro-apoptotic proteins. Exploration of NF-κB inhibitor (Phenylarsine oxide, 0.1 μM) synergistically further increased SVT-induced DR3 and DR5 expressions accompanied with further inhibition of cancer cells growth. Moreover, deletion of DR3 and DR5 by small interfering RNA significantly abolished SVT-induced cell growth inhibitory effects, as well as NF-κB inactivation. Using TNF-related apoptosis-inducing ligand resistance cancer cells (A549 and MCF-7), we also found that SVT enhanced the susceptibility of chemoresistance of these cancer cells through down-regulation of NF-κB, but up-regulation of DR3 and DR5. In vivo study also showed that SVT (0.5 and 1 mg/kg) inhibited tumor growth accompanied with inactivation of NF-κB. Thus, our present study indicates that SVT could be applicable as an anticancer agent for cervical cancer, or as an adjuvant agent for chemoresistant cancer cells.

  3. Binding of sea anemone toxin to receptor sites associated with gating system of sodium channel in synaptic nerve endings in vitro.

    Science.gov (United States)

    Vincent, J P; Balerna, M; Barhanin, J; Fosset, M; Lazdunski, M

    1980-01-01

    Iodination of toxin II from the sea anemone Anemonia sulcata gives a labeled monoiododerivative that retains 80% of the original neurotoxicity. This derivative binds specifically to rat brain synaptosomes at 20 degrees C and pH 7.4 with a second-order rate constant of association ka = 4.6 x 10(4) M-1 sec-1 and a first-order rate constant of dissociation kd = 1.1 x 10(-2) sec-1. The binding occurs on the Na+ channel at a binding site distinct from that of other gating system toxins like batrachotoxin, veratridine, grayanotoxin, aconitine, and pyrethroids. The maximal binding capacity Bmax is 3.2 pmol/mg of protein (i.e., about two sea anemone toxin binding sites per tetrodotoxin binding site) and the Kd is 240 nM for the monoiododerivative and 150 nM for the native toxin. Corresponding binding parameters for the association of a 125I-labeled derivative of toxin II from the scorpion Androctonus australis Hector are Bmax = 0.3 pmol/mg of protein and Kd = 1 nM, whereas the Kd of the unmodified scorpion toxin is 0.6 nM. Competition experiments involving scorpion toxins, sea anemone toxins, and synaptosomes demonstrate that, although the sea anemone toxin is able to displace the scorpion toxin bound to synaptosomes, the scorpion toxin does not displace the sea anemone toxin. The sea anemone toxin but not the scorpion toxin binds to depolarized synaptosomes. Differences between binding properties of the two polypeptide toxins are analyzed in the discussion. PMID:6103536

  4. Selecting key toxins for focused development of elapid snake antivenoms and inhibitors guided by a Toxicity Score

    DEFF Research Database (Denmark)

    Laustsen, Andreas Hougaard; Lohse, Brian; Lomonte, Bruno

    2015-01-01

    For more than 100 years, antivenoms have been produced by traditional methods of immunization of large mammals with mixtures of snake venoms (World Health Organization, 2010 and Gutiérrez et al., 2011). With the introduction of proteomic and transcriptomic tools in the molecular analysis of both ...

  5. Determination of low tetanus or diphtheria antitoxin titers in sera by a toxin neutralization assay and a modified toxin-binding inhibition test

    Directory of Open Access Journals (Sweden)

    M.H. Sonobe

    2007-01-01

    Full Text Available A method for the screening of tetanus and diphtheria antibodies in serum using anatoxin (inactivated toxin instead of toxin was developed as an alternative to the in vivo toxin neutralization assay based on the toxin-binding inhibition test (TOBI test. In this study, the serum titers (values between 1.0 and 19.5 IU measured by a modified TOBI test (Modi-TOBI test and toxin neutralization assays were correlated (P < 0.0001. Titers of tetanus or diphtheria antibodies were evaluated in serum samples from guinea pigs immunized with tetanus toxoid, diphtheria-tetanus or triple vaccine. For the Modi-TOBI test, after blocking the microtiter plates, standard tetanus or diphtheria antitoxin and different concentrations of guinea pig sera were incubated with the respective anatoxin. Twelve hours later, these samples were transferred to a plate previously coated with tetanus or diphtheria antitoxin to bind the remaining anatoxin. The anatoxin was then detected using a peroxidase-labeled tetanus or diphtheria antitoxin. Serum titers were calculated using a linear regression plot of the results for the corresponding standard antitoxin. For the toxin neutralization assay, L+/10/50 doses of either toxin combined with different concentrations of serum samples were inoculated into mice for anti-tetanus detection, or in guinea pigs for anti-diphtheria detection. Both assays were suitable for determining wide ranges of antitoxin levels. The linear regression plots showed high correlation coefficients for tetanus (r² = 0.95, P < 0.0001 and for diphtheria (r² = 0.93, P < 0.0001 between the in vitro and the in vivo assays. The standardized method is appropriate for evaluating titers of neutralizing antibodies, thus permitting the in vitro control of serum antitoxin levels.

  6. Binding kinetics of Clostridium difficile toxins A and B to intestinal brush border membranes from infant and adult hamsters

    Energy Technology Data Exchange (ETDEWEB)

    Rolfe, R.D. (Texas Tech Univ. Health Sciences Center, Lubbock (USA))

    1991-04-01

    This study was undertaken to determine if the relative resistance of neonates and infants to Clostridium difficile-associated intestinal disease can be related to age-dependent differences in intestinal receptors for C. difficile toxins A and B. Brush border membranes (BBMs) from the small intestines of adult and infant hamsters were examined for their ability to bind radiolabeled toxins A and B. (125I)toxin A bound to both infant and adult hamster BBMs at physiological temperature, whereas (125I)toxin B did not bind to the BBMs under any of the conditions examined. The number of (125I)toxin A molecules bound at saturation was approximately 4 x 10(10) per micrograms of membrane protein for adult BBMs and 1 x 10(11) per micrograms of membrane protein for infant BBMs. Scatchard plot analysis suggested the presence of a single class of toxin A binding sites on both infant and adult hamster BBMs. Maximal binding capacity and Kd values were 0.63 pmol/mg of protein and 66.7 nM, respectively, for the infant BBMs, and 0.24 pmol/mg of protein and 27 nM, respectively, for the adult BBMs. Sodium dodecyl sulfate-polyacrylamide gel electrophoretic analyses of extracted BBM proteins revealed differences in the proteins of infant and adult BBMs. However, there were not any detectable differences in the protein bands which bound (125I)toxin A between infant and adult hamsters. The results from these investigations indicate that differences in the binding kinetics of toxins A and/or B to infant and adult hamster BBMs do not account for the observed differences in their susceptibility to C. difficile-associated intestinal disease.

  7. GALACTOSE-BINDING SITE IN ESCHERICHIA-COLI HEAT-LABILE ENTEROTOXIN (LT) AND CHOLERA-TOXIN (CT)

    NARCIS (Netherlands)

    MERRITT, EA; SIXMA, TK; KALK, KH; VANZANTEN, BAM; HOL, WGJ

    The galactose-binding site in cholera toxin and the closely related heat-labile enterotoxin (LT) from Escherichia coil is an attractive target for the rational design of potential anti-cholera drugs. In this paper we analyse the molecular structure of this binding site as seen in several crystal

  8. Neutralization of toxicological activities of medically-relevant Bothrops snake venoms and relevant toxins by two polyvalent bothropic antivenoms produced in Peru and Brazil.

    Science.gov (United States)

    Estevao-Costa, Maria I; Gontijo, Silea S; Correia, Barbara L; Yarleque, Armando; Vivas-Ruiz, Dan; Rodrigues, Edith; Chávez-Olortegui, Carlos; Oliveira, Luciana S; Sanchez, Eladio F

    2016-11-01

    Snakebite envenoming is a neglected public pathology, affecting especially rural communities or isolated areas of tropical and subtropical Latin American countries. The parenteral administration of antivenom is the mainstay and the only validated treatment of snake bite envenoming. Here, we assess the efficacy of polyspecific anti-Bothrops serum (α-BS) produced in the Instituto Nacional de Salud (INS, Peru) and at the Fundação Ezequiel Dias (FUNED, Brazil), to neutralize the main toxic activities induced by five medically-relevant venoms of: Bothrops atrox, B. barnetti, and B. pictus from Peru, and the Brazilian B. jararaca and B. leucurus, all of them inhabiting different geographical locations. Protein electrophoretic patterns of these venoms showed significant differences in composition, number and intensity of bands. Another goal was to evaluate the efficacy and safety of lyophilized α-BS developed at INS to neutralize the detrimental effects of these venoms using in vivo and in vitro assays. The availability of lyophilized α-BS has relevant significance in its distribution to distant rural communities where the access to antivenom in health facilities is more difficult. Despite the fact that different antigen mixtures were used for immunization during antivenom production, our data showed high toxin-neutralizing activity of α-BS raised against Bothrops venoms. Moreover, the antivenom cross-reacted even against venoms not included in the immunization mixture. Furthermore, we have evaluated the efficacy of both α-BS to neutralize key toxic compounds belonging to the predominant protein families of Bothrops snakes. Most significantly, both α-BS cross-specifically neutralized the main toxicological activities e.g. lethality and hemorrhage induced by these venoms. Thus, our data indicate that both α-BS are equally effective to treat snake bite victims inflicted by Bothrops snakes particularly B. atrox, responsible for the largest numbers of human

  9. Identification of a Bacillus thuringiensis Cry8Da toxin-binding glucosidase from the adult Japanese beetle, Popillia japonica.

    Science.gov (United States)

    Yamaguchi, Takuya; Bando, Hisanori; Asano, Shin-ichiro

    2013-06-01

    Cry8Da from Bacillus thuringiensis galleriae SDS-502 has insecticidal activity against both the larvae and adult Japanese beetle (Popillia japonica Newman). The receptor determines the specificity of the insecticidal activity of Cry proteins and hence, in order to reveal the mode of action of Cry toxin, receptor identification is a necessary step. However, a receptor for Cry8-type toxin has not been identified in the Scarabaeidae family of insects. Therefore, we aimed to identify the receptor of Cry8Da toxin in adult P. japonica BBMV. A ligand blot showed the Cry8Da toxin only bound to a 150kDa protein in the BBMV of adult P. japonica. In order to identify the Cry8Da toxin binding protein, it was purified by column chromatography and three internal amino acid sequences were determined. Two of the three internal amino acid sequences shared homology with Coleopteran β-glucosidases. In addition, the fraction containing the Cry8Da toxin binding protein had β-glucosidase activity but no aminopeptidase N and alkaline phosphatase activity, both of which are commonly reported as receptors for Cry toxins in Lepidopteran and Dipteran insects. The β-glucosidase homologous genes could be amplified by PCR using degenerate oligonucleotide primers designed from a conserved sequence of Coleopteran β-glucosidases and an internal amino acid sequence of the Cry8Da toxin binding protein. Taken together, the β-glucosidase in adult P. japonica BBMV is the receptor for B. thuringiensis Cry8Da toxin. Copyright © 2013 Elsevier Inc. All rights reserved.

  10. Binding and Oligomerization of Modified and Native Bt Toxins in Resistant and Susceptible Pink Bollworm.

    Directory of Open Access Journals (Sweden)

    Josue Ocelotl

    Full Text Available Insecticidal proteins from Bacillus thuringiensis (Bt are used extensively in sprays and transgenic crops for pest control, but their efficacy is reduced when pests evolve resistance. Better understanding of the mode of action of Bt toxins and the mechanisms of insect resistance is needed to enhance the durability of these important alternatives to conventional insecticides. Mode of action models agree that binding of Bt toxins to midgut proteins such as cadherin is essential for toxicity, but some details remain unresolved, such as the role of toxin oligomers. In this study, we evaluated how Bt toxin Cry1Ac and its genetically engineered counterpart Cry1AcMod interact with brush border membrane vesicles (BBMV from resistant and susceptible larvae of Pectinophora gossypiella (pink bollworm, a global pest of cotton. Compared with Cry1Ac, Cry1AcMod lacks 56 amino acids at the amino-terminus including helix α-1; previous work showed that Cry1AcMod formed oligomers in vitro without cadherin and killed P. gossypiella larvae harboring cadherin mutations linked with >1000-fold resistance to Cry1Ac. Here we found that resistance to Cry1Ac was associated with reduced oligomer formation and insertion. In contrast, Cry1AcMod formed oligomers in BBMV from resistant larvae. These results confirm the role of cadherin in oligomerization of Cry1Ac in susceptible larvae and imply that forming oligomers without cadherin promotes toxicity of Cry1AcMod against resistant P. gossypiella larvae that have cadherin mutations.

  11. Toxin a from Clostridium difficile binds to rabbit erythrocyte glycolipids with therminal Gal. cap alpha. 1-3Gal. beta. 1-4GlcNaC sequences

    Energy Technology Data Exchange (ETDEWEB)

    Clark, G.F.; Krivan, H.; Wilkins, T.; Smith, D.F.

    1987-05-01

    Toxin A is one of two clostridial toxins implicated as the causative agent of pseudomembranous colitis in patients undergoing postoperative antibiotic therapy. Evidence that the carbohydrate binding determinant for this toxin is a glycoconjugate(s) with non-reducing Gal..cap alpha..1-3Gal..beta..1-4GlcNAc has recently been reported. Specific agglutination of rabbit erythrocytes by Toxin A is inhibited by bovine thyroglobulin and prevented by pretreatment of cells with ..cap alpha..-galactosidase. Total lipid extracts from rabbit erythrocytes were subjected to thin layer chromatography and the chromatogram overlaid with purified /sup 125/I-labeled Toxin A. Two major and several minor toxin-binding glycolipids were detected following autoradiography. The major toxin-binding glycolipids were identified as pentasaccharide- and decasaccharide-ceramides expressing terminal Gal..cap alpha..1-3Gal..beta..1-4GlcNAc sequences. Treatment of the toxin-binding glycolipids with ..cap alpha..-galactosidase abolished binding. Forsmann glycolipid, globoside, Gal..cap alpha..1-4 Gal..beta..1-4Glc-cer, and Gal..cap alpha..1-3Gal..beta..1-4Glc-cer did not bind the toxin. These observations are consistent with the proposed carbohydrate specificity of the toxin for the non-reducing terminal sequence, Gal..cap alpha..1-3Gal..beta..1-4GlcNAc.

  12. New binding site on common molecular scaffold provides HERG channel specificity of scorpion toxin BeKm-1

    DEFF Research Database (Denmark)

    Korolkova, Yuliya V; Bocharov, Eduard V; Angelo, Kamilla

    2002-01-01

    resolved by NMR consists of a short alpha-helix and a triple-stranded antiparallel beta-sheet. By toxin mutagenesis study we identified the residues that are important for the binding of BeKm-1 to the human ERG K+ (HERG) channel. The most critical residues (Tyr-11, Lys-18, Arg-20, Lys-23) are located...... in the alpha-helix and following loop whereas the "traditional" functional site of other short scorpion toxins is formed by residues from the beta-sheet. Thus the unique location of the binding site of BeKm-1 provides its specificity toward the HERG channel....

  13. Isolation and partial characterization of gypsy moth BTR-270, an anionic brush border membrane glycoconjugate that binds Bacillus thuringiensis Cry1A toxins with high affinity

    Science.gov (United States)

    Algimantas P. Valaitis; Jeremy L. Jenkins; Mi Kyong Lee; Donald H. Dean; Karen J. Garner

    2001-01-01

    BTR-270, a gypsy moth (Lymantria dispar) brush border membrane molecule that binds Bacillus thuringiensis (Bt) Cry1A toxins with high affinity, was purified by preparative gel electrophoresis. Rabbit antibodies specific for the Bt toxin-binding molecule were raised. Attempts to label BTR-270 by protein-directed techniques were...

  14. Clostridium botulinum serotype D neurotoxin and toxin complex bind to bovine aortic endothelial cells via sialic acid.

    Science.gov (United States)

    Yoneyama, Tohru; Miyata, Keita; Chikai, Tomoyuki; Mikami, Akifumi; Suzuki, Tomonori; Hasegawa, Kimiko; Ikeda, Toshihiko; Watanabe, Toshihiro; Ohyama, Tohru; Niwa, Koichi

    2008-12-01

    Botulinum neurotoxin (BoNT) is produced as a large toxin complex (L-TC) associated with nontoxic nonhemagglutinin (NTNHA) and three hemagglutinin subcomponents (HA-70, -33 and -17). The binding properties of BoNT to neurons and L-TC to intestinal epithelial cells are well documented, while those to other tissues are largely unknown. Here, to obtain novel insights into the pathogenesis of foodborne botulism, we examine whether botulinum toxins bind to vascular endothelial cells. BoNT and 750 kDa L-TC (a complex of BoNT, NTNHA and HAs) of Clostridium botulinum serotype D were incubated with bovine aortic endothelial cells (BAECs), and binding to the cells was assessed using sodium dodecyl sulfate polyacrylamide gel electrophoresis and Western blot. Both BoNT and L-TC bound to BAECs, with L-TC showing stronger binding. Binding of BoNT and L-TC to BAECs was significantly inhibited by N-acetyl neuraminic acid in the cell culture medium or by treatment of the cells with neuraminidase. However, galactose, lactose or N-acetyl galactosamine did not significantly inhibit toxin binding to the cells. This is the first report demonstrating that BoNT and L-TC bind to BAECs via sialic acid, and this mechanism may be important in the trafficking pathway of BoNT in foodborne botulism.

  15. Immunogenicity test of tetanus component in adsorbed vaccines by toxin binding inhibition test

    Directory of Open Access Journals (Sweden)

    Denise Cristina Souza Matos

    2002-09-01

    Full Text Available Samples from 20 lots of diphtheria-tetanus (adult use dT vaccine and from 20 lots of diphtheria-tetanus-pertussis (DTP vaccine were used to standardize and validate the in vitro toxin binding inhibition (ToBI test for the immunogenicity test of the tetanus component. The levels of tetanus antitoxin obtained by ToBI test were compared to those obtained using the toxin neutralization (TN test in mice routinely employed to perform the quality control of the tetanus component in adsorbed vaccines. The results ranged from 1.8 to 3.5 IU/ml for dT and 2 to 4 IU/ml for DTP by ToBI test and 1.4 to 3 IU/ml for dT and 1.8 to 3.5 IU/ml for DTP by TN in mice. These results were significantly correlated. From this study, it is concluded that the ToBI test is an alternative to the in vivo neutralization procedure in the immunogenicity test of the tetanus component in adsorbed vaccines. A substantial refinement and a reduction in use of animals can be achieved.

  16. Molecular dynamics of the honey bee toxin tertiapin binding to Kir3.2.

    Science.gov (United States)

    Li, Daxu; Chen, Rong; Chung, Shin-Ho

    2016-12-01

    Tertiapin (TPN), a short peptide isolated from the venom of the honey bee, is a potent and selective blocker of the inward rectifier K(+) (Kir) channel Kir3.2. Here we examine in atomic detail the binding mode of TPN to Kir3.2 using molecular dynamics, and deduce the key residue in Kir3.2 responsible for TPN selectivity. The binding of TPN to Kir3.2 is stable when the side chain of either Lys16 (TPN(K16)-Kir3.2) or Lys17 (TPN(K17)-Kir3.2) of the toxin protrudes into the channel pore. However, the binding affinity calculated from only TPN(K17)-Kir3.2 and not TPN(K16)-Kir3.2 is consistent with experiment, suggesting that Lys17 is the most plausible pore-blocking residue. The alanine mutation of Kir3.2-Glu127, which is not present in TPN-resistant channels, reduces the inhibitory ability of TPN by over 50 fold in TPN(K17)-Kir3.2, indicating that Kir3.2-Glu127 is important for the selectivity of TPN. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Human mannose-binding lectin inhibitor prevents Shiga toxin-induced renal injury

    DEFF Research Database (Denmark)

    Ozaki, Masayuki; Kang, Yulin; Tan, Ying Siow

    2016-01-01

    Hemolytic uremic syndrome caused by Shiga toxin-producing Escherichia coli (STEC HUS) is a worldwide endemic problem, and its pathophysiology is not fully elucidated. Here we tested whether the mannose-binding lectin (MBL2), an initiating factor of lectin complement pathway activation, plays......, anemia, and thrombocytopenia and increased serum creatinine, free serum hemoglobin, and cystatin C levels, but a significantly decreased glomerular filtration rate compared with control/sham mice. Immunohistochemical staining revealed renal C3d deposition and fibrin deposition in glomeruli in Stx-2......-injected mice. Treatment with 3F8 completely inhibited serum MBL2 levels and significantly attenuated Stx-2 induced-renal injury, free serum hemoglobin levels, renal C3d, and fibrin deposition and preserved the glomerular filtration rate. Thus, MBL2 inhibition significantly protected against complement...

  18. Venom of the Coral Snake Micrurus clarki: Proteomic Profile, Toxicity, Immunological Cross-Neutralization, and Characterization of a Three-Finger Toxin

    Directory of Open Access Journals (Sweden)

    Bruno Lomonte

    2016-05-01

    Full Text Available Micrurus clarki is an uncommon coral snake distributed from the Southeastern Pacific of Costa Rica to Western Colombia, for which no information on its venom could be found in the literature. Using a ‘venomics’ approach, proteins of at least nine families were identified, with a moderate predominance of three-finger toxins (3FTx; 48.2% over phospholipase A2 (PLA2; 36.5%. Comparison of this venom profile with those of other Micrurus species suggests that it may represent a more balanced, ‘intermediate’ type within the dichotomy between 3FTx- and PLA2-predominant venoms. M. clarki venom was strongly cross-recognized and, accordingly, efficiently neutralized by an equine therapeutic antivenom against M. nigrocinctus, revealing their high antigenic similarity. Lethal activity for mice could be reproduced by a PLA2 venom fraction, but, unexpectedly, not by fractions corresponding to 3FTxs. The most abundant venom component, hereby named clarkitoxin-I, was identified as a short-chain (type I 3FTx, devoid of lethal effect in mice, whose target remains to be defined. Its amino acid sequence of 66 residues shows high similarity with predicted sequences of venom gland transcripts described for M. fulvius, M. browni, and M. diastema.

  19. Venom of the Coral Snake Micrurus clarki: Proteomic Profile, Toxicity, Immunological Cross-Neutralization, and Characterization of a Three-Finger Toxin.

    Science.gov (United States)

    Lomonte, Bruno; Sasa, Mahmood; Rey-Suárez, Paola; Bryan, Wendy; Gutiérrez, José María

    2016-05-05

    Micrurus clarki is an uncommon coral snake distributed from the Southeastern Pacific of Costa Rica to Western Colombia, for which no information on its venom could be found in the literature. Using a 'venomics' approach, proteins of at least nine families were identified, with a moderate predominance of three-finger toxins (3FTx; 48.2%) over phospholipase A₂ (PLA₂; 36.5%). Comparison of this venom profile with those of other Micrurus species suggests that it may represent a more balanced, 'intermediate' type within the dichotomy between 3FTx- and PLA₂-predominant venoms. M. clarki venom was strongly cross-recognized and, accordingly, efficiently neutralized by an equine therapeutic antivenom against M. nigrocinctus, revealing their high antigenic similarity. Lethal activity for mice could be reproduced by a PLA₂ venom fraction, but, unexpectedly, not by fractions corresponding to 3FTxs. The most abundant venom component, hereby named clarkitoxin-I, was identified as a short-chain (type I) 3FTx, devoid of lethal effect in mice, whose target remains to be defined. Its amino acid sequence of 66 residues shows high similarity with predicted sequences of venom gland transcripts described for M. fulvius, M. browni, and M. diastema.

  20. Phase Partitioning of GM1 and Its Bodipy-Labeled Analog Determine Their Different Binding to Cholera Toxin

    DEFF Research Database (Denmark)

    Rissanen, Sami; Grzybek, Michal; Orłowski, Adam

    2017-01-01

    membrane vesicles and giant unilamellar vesicles, specific binding of Cholera Toxin (CTxB) to GM1 glycolipids is a commonly used strategy to label raft domains or Lo membrane environments. However, these studies often use acyl-chain labeled bodipy-GM1 (bdGM1), whose headgroup accessibility and membrane...

  1. Toxin A from Clostridium difficile binds to rabbit erythrocyte glycolipids with terminal Gal alpha 1-3Gal beta 1-4GlcNAc sequences

    Energy Technology Data Exchange (ETDEWEB)

    Clark, G.F.; Krivan, H.C.; Wilkins, T.D.; Smith, D.F.

    1987-08-15

    The binding of Toxin A isolated from Clostridium difficile to rabbit erythrocyte glycolipids has been studied. Total lipid extracts from rabbit erythrocytes were subjected to thin-layer chromatography and toxin-binding glycolipids detected by using /sup 125/I-labeled Toxin A in a direct binding overlay technique. Two major and several minor toxin-binding glycolipids were detected in rabbit erythrocytes by this method. The results of structural analyses of the major toxin-binding glycolipids were consistent with a pentasaccharide-ceramide (Gal alpha 1-3Gal beta 1-4GlcNAc beta 1-3Gal beta 1-4Glc-Cer) and a branched decasaccharide-ceramide (Gal alpha 1-3Gal beta 1-4GlcNAc beta 1-3(Gal alpha 1-3Gal beta 1-4GlcNAc beta 1-6)Gal beta 1-4GlcNAc beta 1-3Gal beta 1-4Glc-Cer) previously identified as the two most abundant glycolipids in rabbit erythrocytes. /sup 125/I-Toxin A binding to these glycolipids could be inhibited by bovine thyroglobulin, monospecific antiserum to the toxin, or by treatment of the glycolipids with alpha-galactosidase. The absence of toxin interaction with isoglobotriaosylceramide (Gal alpha 1-3Gal beta 1-4Glc-Cer) isolated from canine intestine suggested that the GlcNAc residue present in the terminal Gal alpha 1-3Gal beta 1-4GLcNAc sequence common to all known toxin binding glycoconjugates is required for carbohydrate-specific recognition by Toxin A. These observations are consistent with the proposed carbohydrate binding specificity of Toxin A for the nonreducing terminal sequence, Gal alpha 1-3Gal beta 1-4GlcNAc.

  2. Identification of amino acids required for receptor binding and toxicity of the Bacillus sphaericus binary toxin.

    Science.gov (United States)

    Singkhamanan, Kamonnut; Promdonkoy, Boonhiang; Chaisri, Urai; Boonserm, Panadda

    2010-02-01

    Bacillus sphaericus produces a mosquito-larvicidal binary toxin composed of BinB and BinA subunits. BinA is important for toxicity, whereas BinB acts as a specific receptor-binding component. To study the functional significance of two regions that are only present in BinB, four block mutations and two single mutations were initially introduced: (111)YLD(113)-->(111)AAA(113), (115)NNH(117)-->(115)AAA(117), (143)GEQ(145)-->(143)AAA(145), (147)FQFY(150)-->(147)AAAA(150), N114A and F146A. Only the replacements at (147)FQFY(150) resulted in a total loss of toxicity to Culex quinquefasciatus larvae. Further single alanine substitutions in this region, F147A, Q148A, F149A and Y150A, were introduced to identify residues playing a critical role in mosquito-larvicidal activity. Larvicidal activity assays revealed that only F149A and Y150A mutants exhibited a total loss of toxicity. The in vitro interaction assays demonstrated that all BinB mutants are able to interact with BinA. Immunohistochemistry analysis revealed that only the Y150A mutant was unable to bind to the larval midgut, suggesting an important role of this residue in receptor binding of the BinB subunit. Conservative aromatic substitutions at F149 and Y150 resulted in full recovery of larvicidal activity, indicating that the aromaticity of F149 and Y150 is a key determinant of larvicidal activity, possibly playing a key role in the membrane interaction and receptor binding.

  3. Bp-13 PLA2: Purification and Neuromuscular Activity of a New Asp49 Toxin Isolated from Bothrops pauloensis Snake Venom

    Directory of Open Access Journals (Sweden)

    Georgina Sucasaca-Monzón

    2015-01-01

    Full Text Available A new PLA2 (Bp-13 was purified from Bothrops pauloensis snake venom after a single chromatographic step of RP-HPLC on μ-Bondapak C-18. Amino acid analysis showed a high content of hydrophobic and basic amino acids and 14 half-cysteine residues. The N-terminal sequence showed a high degree of homology with basic Asp49 PLA2 myotoxins from other Bothrops venoms. Bp-13 showed allosteric enzymatic behavior and maximal activity at pH 8.1, 36°–45°C. Full Bp-13 PLA2 activity required Ca2+; its PLA2 activity was inhibited by Mg2+, Mn2+, Sr2+, and Cd2+ in the presence and absence of 1 mM Ca2+. In the mouse phrenic nerve-diaphragm (PND preparation, the time for 50% paralysis was concentration-dependent (P0.05. The main effect of this new Asp49 PLA2 of Bothrops pauloensis venom is on muscle fiber sarcolemma, with avian preparation being less responsive than rodent preparation. The study enhances biochemical and pharmacological characterization of B. pauloensis venom.

  4. Phospholipases a2 from Viperidae snakes: Differences in membranotropic activity between enzymatically active toxin and its inactive isoforms.

    Science.gov (United States)

    Ghazaryan, Narine A; Ghulikyan, Lusine; Kishmiryan, Arsen; Andreeva, Tatyana V; Utkin, Yuri N; Tsetlin, Victor I; Lomonte, Bruno; Ayvazyan, Naira M

    2015-02-01

    We describe the interaction of various phospholipases A2 (PLA2) from snake venoms of the family Viperidae (Macrovipera lebetina obtusa, Vipera ursinii renardi, Bothrops asper) with giant unilamellar vesicles (GUVs) composed of natural brain phospholipids mixture, visualized through fluorescence microscopy. The membrane fluorescent probes 8-anilino-1-naphthalenesulfonicacid (ANS), LAUDRAN and PRODAN were used to assess the state of the membrane and specifically mark the lipid packing and membrane fluidity. Our results have shown that the three PLA2s which contain either of aspartic acid, serine, or lysine residues at position 49 in the catalytic center, have different effects on the vesicles. The PLA2 with aspartic acid at this position causes the oval deformation of the vesicles, while serine and lysine-containing enzymes lead to an appreciable increase of fluorescence intensity in the vesicles membrane, wherein the shape and dimensions of GUVs have not changed, but in this case GUV aggregation occurs. LAURDAN and PRODAN detect the extent of water penetration into the bilayer surface. We calculated generalized polarization function (GP), showing that for all cases (D49 PLA2, S49 PLA2 and K49 PLA2) both LAUDRAN and PRODAN GP values decrease. A higher LAURDAN GP is indicative of low water penetration in the lipid bilayer in case of K49 PLA2 compared with D49 PLA2, whereas the PRODAN mainly gives information when lipid is in liquid crystalline phase. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Increments in cytokines and matrix metalloproteinases in skeletal muscle after injection of tissue-damaging toxins from the venom of the snake Bothrops asper

    Directory of Open Access Journals (Sweden)

    Alexandra Rucavado

    2002-01-01

    Full Text Available Envenomations by the snake Bothrops asper are characterized by prominent local tissue damage (i.e. myonecrosis, blistering, hemorrhage and edema. Various phospholipases A2 and metalloproteinases that induce local pathological alterations have been purified from this venom. Since these toxins induce a conspicuous inflammatory response, it has been hypothesized that inflammatory mediators may contribute to the local pathological alterations described. This study evaluated the local production of cytokines and matrix metalloproteinases (MMPs as a consequence of intramuscular injections of an Asp-49 myotoxic phospholipase A2 (myotoxin III (MT-III and a P-I type hemorrhagic metalloproteinase (BaP1 isolated from B. asper venom. Both enzymes induced prominent tissue alterations and conspicuous increments in interleukin (IL-1β, IL-6 and a number of MMPs, especially gelatinase MMP-9, rapidly after injection. In contrast, no increments in tumor necrosis factor-α (TNF-α and interferon-γ were detected. In agreement, MT-III and BaP1 did not induce the synthesis of TNF-α by resident peritoneal macrophages in vitro. Despite the conspicuous expression of latent forms of MMPs in muscle, evidenced by zymography, there were no increments in activated MMP-2 and only a small increase in activated MMP-9, as detected by a functional enzymatic assay. This suggests that MMP activity was regulated by a highly controlled activation of latent forms and, probably, by a concomitant synthesis of MMP inhibitors. Since no hemorrhage nor dermonecrosis were observed after injection of MT-III, despite a prominent increase in MMP expression, and since inflammatory exudate did not enhance hemorrhage induced by BaP1, it is suggested that endogenous MMPs released in the tissue are not responsible for the dermonecrosis and hemorrhage characteristic of B. asper envenomation. Moreover, pretreatment of mice with the peptidomimetic MMP inhibitor batimastat did not reduce myotoxic nor

  6. Exploring the binding mechanism and kinetics of Piperine with snake venom secretory Phospholipase A2.

    Science.gov (United States)

    Christian Bharathi, A; Srinivas, Sistla; Syed Ibrahim, B

    2018-01-01

    Secreted venom Phospholipase A2 is highly responsible for pharmacological effects like neurotoxicity, myotoxicity, hemolytic, anti-coagulation, and platelet aggregation. Neutralization of these pharmacological behaviors is one of the challenges existing for many decades and a potent drug compound for this is very much needed to control local effects of venom sPLA2. In this study, we investigated binding mechanism and kinetics of inhibition of Piperine (major constitute of Piper nigrum) with sPLA2 using DFT, MD simulation, MM-PBSA, and SPR method. Frontier MO properties were suggested that it procured better chemical reactivity and druglikeness and binding mode of Piperine with EcPLA2 defined that it occupied well in N-terminal hydrophobic cleft. The persistence of Piperine interactions with and without calcium ion was analyzed and confirmed by MD simulation analysis. The dPCA-based FEL shows the nature of apo- and Piperine-bound conformational behavior of EcPLA2 including intermediate forms. Further, binding energy of Piperine was calculated by high-throughput MM-PBSA which states that calcium ion presence enhances the Piperine binding by additional electrostatic interactions. Finally, kinetics of inhibition between Piperine and EcPLA2 implied that it secured better binding affinity (KD: as 1.708 pM) and the result gives clear evidence for the binding mechanism and binding energy calculated. In conclusion, Piperine was authenticated with better drug ability, entrenched binding interaction, and robust kinetics of inhibition with EcPLA2 through which it can become an exceeding drug candidate for pharmacological as well as catalytic activity of sPLA2.

  7. Screening Mixtures of Small Molecules for Binding to Multiple Sites on the Surface Tetanus Toxin C Fragment by Bioaffinity NMR

    Energy Technology Data Exchange (ETDEWEB)

    Cosman, M; Zeller, L; Lightstone, F C; Krishnan, V V; Balhorn, R

    2002-01-01

    The clostridial neurotoxins include the closely related tetanus (TeNT) and botulinum (BoNT) toxins. Botulinum toxin is used to treat severe muscle disorders and as a cosmetic wrinkle reducer. Large quantities of botulinum toxin have also been produced by terrorists for use as a biological weapon. Because there are no known antidotes for these toxins, they thus pose a potential threat to human health whether by an accidental overdose or by a hostile deployment. Thus, the discovery of high specificity and affinity compounds that can inhibit their binding to neural cells can be used as antidotes or in the design of chemical detectors. Using the crystal structure of the C fragment of the tetanus toxin (TetC), which is the cell recognition and cell surface binding domain, and the computational program DOCK, sets of small molecules have been predicted to bind to two different sites located on the surface of this protein. While Site-1 is common to the TeNT and BoNTs, Site-2 is unique to TeNT. Pairs of these molecules from each site can then be linked together synthetically to thereby increase the specificity and affinity for this toxin. Electrospray ionization mass spectroscopy was used to experimentally screen each compound for binding. Mixtures containing binders were further screened for activity under biologically relevant conditions using nuclear magnetic resonance (NMR) methods. The screening of mixtures of compounds offers increased efficiency and throughput as compared to testing single compounds and can also evaluate how possible structural changes induced by the binding of one ligand can influence the binding of the second ligand. In addition, competitive binding experiments with mixtures containing ligands predicted to bind the same site could identify the best binder for that site. NMR transfer nuclear Overhauser effect (trNOE) confirm that TetC binds doxorubicin but that this molecule is displaced by N-acetylneuraminic acid (sialic acid) in a mixture that

  8. Development of IgY antibodies against anti-snake toxins endowed with highly lethal neutralizing activity.

    Science.gov (United States)

    da Rocha, David Gitirana; Fernandez, Jorge Hernandez; de Almeida, Cláudia Maria Costa; da Silva, Cláudia Letícia; Magnoli, Fábio Carlos; da Silva, Osmair Élder; da Silva, Wilmar Dias

    2017-08-30

    Snakebite envenoming is a major neglected disease related to poverty in developing countries. Treatment involves the administration of a specific antivenom serum and auxiliary therapies, if necessary. The improvement of antibodies is of great importance for the technological advancement of antivenom therapy and to reduce the morbidity and mortality associated with this medical burden. In the present study, adult hens were immunized nine times with 20μg of B. arietans or C. d. terrificus venoms at three-week intervals between immunizations. Developing antibodies presented increasing avidity and affinity to antigenic toxin epitopes along immunization, attaining a plateau after the seventh immunization. Pooled egg yolk-purified IgY antivenom antibodies, subjected to in vitro-in vivo lethality assay using Swiss adult mice, exhibited potent venom lethal neutralizing activity. Taken together, chickens under the described immunization schedule were considered alternative candidates for antivenom production. Lower maintenance costs, a simple antibody manufacturing process and immunization suffering restrictions are additional advantages. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Binding of adenine to Stx2, the protein toxin from Escherichia coli O157:H7

    Energy Technology Data Exchange (ETDEWEB)

    Fraser, Marie E., E-mail: frasm@ucalgary.ca [Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary AB T2N 1N4 (Canada); Cherney, Maia M. [Group in Protein Structure and Function, Department of Biochemistry, University of Alberta, Edmonton AB T6G 2H7 (Canada); Marcato, Paola [Department of Medical Microbiology and Immunology, University of Alberta, Edmonton AB T6G 2H7 (Canada); Mulvey, George L.; Armstrong, Glen D. [Department of Microbiology and Infectious Diseases, University of Calgary, 3330 Hospital Drive NW, Calgary AB T2N 4N1 (Canada); James, Michael N. G. [Group in Protein Structure and Function, Department of Biochemistry, University of Alberta, Edmonton AB T6G 2H7 (Canada); Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary AB T2N 1N4 (Canada)

    2006-07-01

    Crystals of Stx2 were grown in the presence of adenosine and adenine. In both cases, the resulting electron density showed only adenine bound at the active site of the A subunit, proving that the holotoxin is an active N-glycosidase. Stx2 is a protein toxin whose catalytic subunit acts as an N-glycosidase to depurinate a specific adenine base from 28S rRNA. In the holotoxin, the catalytic portion, A1, is linked to the rest of the A subunit, A2, and A2 interacts with the pentameric ring formed by the five B subunits. In order to test whether the holotoxin is active as an N-glycosidase, Stx2 was crystallized in the presence of adenosine and adenine. The crystals diffracted to ∼1.8 Å and showed clear electron density for adenine in the active site. Adenosine had been cleaved, proving that Stx2 is an active N-glycosidase. While the holotoxin is active against small substrates, it would be expected that the B subunits would interfere with the binding of the 28S rRNA.

  10. Snake bites

    Science.gov (United States)

    ... bites by any of the following: Cobra Copperhead Coral snake Cottonmouth (water moccasin) Rattlesnake Various snakes found at ... Swelling Thirst Tiredness Tissue damage Weakness Weak pulse Coral snake bites may be painless at first. Major symptoms ...

  11. Comparative analysis of Bacillus thuringiensis toxin binding to gypsy moth, browntail moth, and douglas-fir tussock moth midgut tissue sections using fluorescence microscopy

    Science.gov (United States)

    Algimantas P. Valaitis; John D. Podgwaite

    2011-01-01

    Many strains of Bacillus thuringiensis (Bt) produce insecticidal proteins, also referred to as Cry toxins, in crystal inclusions during sporulation. When ingested by insects, the Cry toxins bind to receptors on the brush border midgut epithelial cells and create pores in the epithelial gut membranes resulting in the death of...

  12. Identification of Bacillus thuringiensis Cry3Aa toxin domain II loop 1 as the binding site of Tenebrio molitor cadherin repeat CR12.

    Science.gov (United States)

    Zúñiga-Navarrete, Fernando; Gómez, Isabel; Peña, Guadalupe; Amaro, Itzel; Ortíz, Ernesto; Becerril, Baltazar; Ibarra, Jorge E; Bravo, Alejandra; Soberón, Mario

    2015-04-01

    Bacillus thuringiensis Cry toxins exert their toxic effect by specific recognition of larval midgut proteins leading to oligomerization of the toxin, membrane insertion and pore formation. The exposed domain II loop regions of Cry toxins have been shown to be involved in receptor binding. Insect cadherins have shown to be functionally involved in toxin binding facilitating toxin oligomerization. Here, we isolated a VHH (VHHA5) antibody by phage display that binds Cry3Aa loop 1 and competed with the binding of Cry3Aa to Tenebrio molitor brush border membranes. VHHA5 also competed with the binding of Cry3Aa to a cadherin fragment (CR12) that was previously shown to be involved in binding and toxicity of Cry3Aa, indicating that Cry3Aa binds CR12 through domain II loop 1. Moreover, we show that a loop 1 mutant, previously characterized to have increased toxicity to T. molitor, displayed a correlative enhanced binding affinity to T. molitor CR12 and to VHHA5. These results show that Cry3Aa domain II loop 1 is a binding site of CR12 T. molitor cadherin. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Heterologous protection against alpha toxins of Clostridium perfringens and Staphylococcus aureus induced by binding domain recombinant chimeric protein.

    Science.gov (United States)

    Uppalapati, Siva R; Kingston, Joseph J; Murali, Harishchandra S; Batra, Harsh V

    2014-05-23

    Clostridium perfringens and Staphylococcus aureus are the two important bacteria frequently associated with majority of the soft tissue infections. The severity and progression of the diseases caused by these pathogens are attributed primarily to the alpha toxins they produce. Previously, we synthesized a non-toxic chimeric molecule r-αCS encompassing the binding domains of C. perfringens and S. aureus alpha toxins and demonstrated that the r-αCS hyperimmune polysera reacts with both the native wild type toxins. In the present report, we evaluated efficacy of r-αCS in conferring protection against C. perfringens and S. aureus alpha toxin infections in murine model. Immunization of BALB/c with r-αCS was effective in inducing both high titers of serum anti-r-αCS antibodies after three administrations. Sub-typing the antibody pool revealed high proportions of IgG1 indicating a Th2-polarized immune response. The r-αCS stimulated the proliferation of splenocytes from the immunized mice upon re-induction by the antigen, in vitro. The levels of interleukin-10 increased while TNF-α was found to be downregulated in the r-αCS induced splenocytes. Mice immunized with r-αCS were protected against intramuscular challenge with 5×LD100 doses of C. perfringens and S. aureus alpha toxins with >80% survival, which killed control animals within 48-72h. Passive immunization of mice with anti-r-αCS serum resulted in 50-80% survival. Our results indicate that r-αCS is a remarkable antigen with protective efficacy against alpha toxin mediated C. perfringens and S. aureus soft tissue co-infections. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Snake bite: coral snakes.

    Science.gov (United States)

    Peterson, Michael E

    2006-11-01

    North American coral snakes are distinctively colored beginning with a black snout and an alternating pattern of black, yellow, and red. They have fixed front fangs and a poorly developed system for venom delivery, requiring a chewing action to inject the venom. The severity of a coral snake bite is related to the volume of venom injected and the size of the victim. The length of the snake correlates positively with the snakes venom yield. Coral snake venom is primarily neurotoxic with little local tissue reaction or pain at the bite site. The net effect of the neurotoxins is a curare like syndrome. In canine victims there have been reports of marked hemolysis with severe anemia and hemoglobinuria. The onset of clinical signs may be delayed for as much as 10 to 18 hours. The victim begins to have alterations in mental status and develops generalized weakness and muscle fasciculations. Progression to paralysis of the limbs and respiratory muscles then follows. The best flied response to coral snake envenomation is rapid transport to a veterinary medical facility capable of 24 hour critical care and assisted ventilation. First aid treatment advocated in Australia for Elapid bites is the immediate use of a compression bandage. The victim should be hospitalized for a minimum of 48 hours for continuous monitoring. The only definitive treatment for coral snake envenomation is the administration of antivenin (M. fulvius). Once clinical signs of coral snake envenomation become manifest they progress with alarming rapidity and are difficult to reverse. If antivenin is not available or if its administration is delayed, supportive care includes respiratory support. Assisted mechanical ventilation can be used but may have to be employed for up to 48 to 72 hours.

  15. Comparison of proteomic profiles of the venoms of two of the 'Big Four' snakes of India, the Indian cobra (Naja naja) and the common krait (Bungarus caeruleus), and analyses of their toxins.

    Science.gov (United States)

    Choudhury, Manisha; McCleary, Ryan J R; Kesherwani, Manish; Kini, R Manjunatha; Velmurugan, Devadasan

    2017-09-01

    Snake venoms are mixtures of biologically-active proteins and peptides, and several studies have described the characteristics of some of these toxins. However, complete proteomic profiling of the venoms of many snake species has not yet been done. The Indian cobra (Naja naja) and common krait (Bungarus caeruleus) are elapid snake species that are among the 'Big Four' responsible for the majority of human snake envenomation cases in India. As understanding the composition and complexity of venoms is necessary for successful treatment of envenomation in humans, we utilized three different proteomic profiling approaches to characterize these venoms: i) one-dimensional SDS-PAGE coupled with in-gel tryptic digestion and electrospray tandem mass spectrometry (ESI-LC-MS/MS) of individual protein bands; ii) in-solution tryptic digestion of crude venoms coupled with ESI-LC-MS/MS; and iii) separation by gel-filtration chromatography coupled with tryptic digestion and ESI-LC-MS/MS of separated fractions. From the generated data, 81 and 46 different proteins were identified from N. naja and B. caeruleus venoms, respectively, belonging to fifteen different protein families. Venoms from both species were found to contain a variety of phospholipases A2 and three-finger toxins, whereas relatively higher numbers of snake venom metalloproteinases were found in N. naja compared to B. caeruleus venom. The analyses also identified less represented venom proteins including L-amino acid oxidases, cysteine-rich secretory proteins, 5'-nucleotidases and venom nerve growth factors. Further, Kunitz-type serine protease inhibitors, cobra venom factors, phosphodiesterases, vespryns and aminopeptidases were identified in the N. naja venom, while acetylcholinesterases and hyaluronidases were found in the B. caeruleus venom. We further analyzed protein coverage (Lys/Arg rich and poor regions as well as potential glycosylation sites) using in-house software. These studies expand our

  16. Identification and Characterization of Hyphantria cunea Aminopeptidase N as a Binding Protein of Bacillus thuringiensis Cry1Ab35 Toxin

    Directory of Open Access Journals (Sweden)

    Yakun Zhang

    2017-11-01

    Full Text Available The fall webworm, Hyphantria cunea (Drury is a major invasive pest in China. Aminopeptidase N (APN isoforms in lepidopteran larvae midguts are known for their involvement in the mode of action of insecticidal crystal (Cry proteins from Bacillus thuringiensis. In the present work, we identified a putative Cry1Ab toxin-binding protein, an APN isoform designated HcAPN3, in the midgut of H. cunea by ligand blot and mass spectrometry. HcAPN3 was highly expressed throughout all larval developmental stages and was abundant in the midgut and hindgut tissues. HcAPN3 was down-regulated at 6 h, then was up-regulated significantly at 12 h and 24 h after Cry1Ab toxin treatment. We expressed HcAPN3 in insect cells and detected its interaction with Cry1Ab toxin by ligand blot assays. Furthermore, RNA interference (RNAi against HcAPN3 using oral delivery and injection of double-stranded RNA (dsRNA resulted in a 61–66% decrease in transcript level. Down-regulating of the expression of HcAPN3 was closely associated with reduced susceptibility of H. cunea to Cry1Ab. In addition, the HcAPN3E fragment peptide expressed in Escherichia coli enhanced Cry1Ab toxicity against H. cunea larvae. This work represents the first evidence to suggest that an APN in H. cunea is a putative binding protein involved in Cry1Ab susceptibility.

  17. Toxin inhibition in C. crescentus VapBC1 is mediated by a flexible pseudo-palindromic protein motif and modulated by DNA binding

    DEFF Research Database (Denmark)

    Bendtsen, Kirstine Louise; Xu, Kehan; Luckmann, Majbritt

    2017-01-01

    Expression of bacterial type II toxin-antitoxin (TA) systems is regulated at the transcriptional level through direct binding of the antitoxin to pseudo-palindromic sequences on operator DNA. In this context, the toxin functions as a co-repressor by stimulating DNA binding through direct...... for binding and inactivation of the VapC1 toxin dimer. Sequence analysis of 4127 orthologous VapB sequences reveals that such palindromic protein sequences are widespread and unique to bacterial and archaeal VapB antitoxins suggesting a general principle governing regulation of VapBC TA systems. Finally......, a structure of C-terminally truncated VapB1 bound to VapC1 reveals discrete states of the TA interaction that suggest a structural basis for toxin activation in vivo....

  18. Spatial location of neutralizing and non-neutralizing B cell epitopes on domain 1 of ricin toxin's binding subunit.

    Directory of Open Access Journals (Sweden)

    Yinghui Rong

    Full Text Available Ricin toxin's binding subunit (RTB is a galactose-/N-acetylgalactosamine (Gal/GalNac-specific lectin that mediates uptake and intracellular trafficking of ricin within mammalian cells. Structurally, RTB consists of two globular domains, each divided into three homologous sub-domains (α, β, γ. In this report, we describe five new murine IgG monoclonal antibodies (mAbs against RTB: MH3, 8A1, 8B3, LF1, and LC5. The mAbs have similar binding affinities (KD for ricin holotoxin, but displayed a wide range of in vitro toxin-neutralizing activities. Competition ELISAs indicate that the two most potent toxin-neutralizing mAbs (MH3, 8A1, as well as one of the moderate toxin-neutralizing mAbs (LF1, recognize distinct epitopes near the low affinity Gal recognition domain in RTB subdomain 1α. Evaluated in a mouse model of systemic ricin challenge, all five mAbs afforded some benefit against intoxication, but only MH3 was protective. However, neither MH3 nor 24B11, another well-characterized mAb against RTB subdomain 1α, could passively protect mice against a mucosal (intranasal ricin challenge. This is in contrast to SylH3, a previously characterized mAb directed against an epitope near RTB's high affinity Gal/GalNac recognition element in sub-domain 2γ, which protected animals against systemic and mucosal ricin exposure. SylH3 was significantly more effective than MH3 and 24B11 at blocking ricin attachment to host cell receptors, suggesting that mucosal immunity to ricin is best imparted by antibodies that target RTB's high affinity Gal/GalNac recognition element in subdomain 2γ, not the low affinity Gal recognition domain in subdomain 1α.

  19. Differential neutralizing activities of a single domain camelid antibody (VHH specific for ricin toxin's binding subunit (RTB.

    Directory of Open Access Journals (Sweden)

    Cristina Herrera

    Full Text Available Ricin, a member of the A-B family of ribosome-inactivating proteins, is classified as a Select Toxin by the Centers for Disease Control and Prevention because of its potential use as a biothreat agent. In an effort to engineer therapeutics for ricin, we recently produced a collection of alpaca-derived, heavy-chain only antibody VH domains (VHH or "nanobody" specific for ricin's enzymatic (RTA and binding (RTB subunits. We reported that one particular RTB-specific VHH, RTB-B7, when covalently linked via a peptide spacer to different RTA-specific VHHs, resulted in heterodimers like VHH D10/B7 that were capable of passively protecting mice against a lethal dose challenge with ricin. However, RTB-B7 itself, when mixed with ricin at a 1 ∶ 10 toxin:antibody ratio did not afford any protection in vivo, even though it had demonstrable toxin-neutralizing activity in vitro. To better define the specific attributes of antibodies associated with ricin neutralization in vitro and in vivo, we undertook a more thorough characterization of RTB-B7. We report that RTB-B7, even at 100-fold molar excess (toxin:antibody was unable to alter the toxicity of ricin in a mouse model. On the other hand, in two well-established cytotoxicity assays, RTB-B7 neutralized ricin with a 50% inhibitory concentration (IC50 that was equivalent to that of 24B11, a well-characterized and potent RTB-specific murine monoclonal antibody. In fact, RTB-B7 and 24B11 were virtually identical when compared across a series of in vitro assays, including adherence to and neutralization of ricin after the toxin was pre-bound to cell surface receptors. RTB-B7 differed from both 24B11 and VHH D10/B7 in that it was relatively less effective at blocking ricin attachment to receptors on host cells and was not able to form high molecular weight toxin:antibody complexes in solution. Whether either of these activities is important in ricin toxin neutralizing activity in vivo remains to be determined.

  20. [Toxins as a biological weapon].

    Science.gov (United States)

    Płusa, Tadeusz

    2015-09-01

    The criteria for recognizing a chemical compound for the toxin are vague and gave it the possibility of inclusion in this group a number of biological agents. Toxins list is extensive, but the interest is focused on bacterial toxins, poisons derived from snake venoms, algae and plant proteins, and small molecules. Particular attention is focused on the so-called "sea" toxins, which include tetrodotoxin, brevetoxin and saxitoxin. This indicates the search for a new hitherto unknown potential bioterrorist threats. © 2015 MEDPRESS.

  1. Toxin inhibition in C. crescentus VapBC1 is mediated by a flexible pseudo-palindromic protein motif and modulated by DNA binding

    DEFF Research Database (Denmark)

    Bendtsen, Kirstine L; Xu, Kehan; Luckmann, Majbritt

    2017-01-01

    interaction with the antitoxin. Here, we determine crystal structures of the complete 90 kDa heterooctameric VapBC1 complex from Caulobacter crescentus CB15 both in isolation and bound to its cognate DNA operator sequence at 1.6 and 2.7 Å resolution, respectively. DNA binding is associated with a dramatic......Expression of bacterial type II toxin-antitoxin (TA) systems is regulated at the transcriptional level through direct binding of the antitoxin to pseudo-palindromic sequences on operator DNA. In this context, the toxin functions as a co-repressor by stimulating DNA binding through direct...... for binding and inactivation of the VapC1 toxin dimer. Sequence analysis of 4127 orthologous VapB sequences reveals that such palindromic protein sequences are widespread and unique to bacterial and archaeal VapB antitoxins suggesting a general principle governing regulation of VapBC TA systems. Finally...

  2. cDNA cloning and expression of Bacillus thuringiensis Cry1Aa toxin binding 120 kDa aminopeptidase N from Bombyx mori.

    Science.gov (United States)

    Yaoi, K; Nakanishi, K; Kadotani, T; Imamura, M; Koizumi, N; Iwahana, H; Sato, R

    1999-01-18

    Bacillus thuringiensis Cry1Aa toxin binds to a 120 kDa putative receptor protein in the Bombyx mori midgut. Recently, this protein was purified and identified as glycosyl-phosphatidylinositol (GPI) anchored aminopeptidase N (APN). In this study, a full-length cDNA thought to encode this 120 kDa APN was isolated and sequenced. It has a 2958 bp ORF encoding 986 amino acids. In the deduced amino acid sequence, we identified GPI-anchor and zinc-metallopeptidase signals, which are the same as those of APNs of other insects that are reported to be putative Cry1 toxin receptors. The B. mori APN amino acid sequence also has a high similarity with those of the other APNs. Subsequently, the recombinant APN was expressed by Escherichia coli and its Cry1Aa toxin binding ability was analyzed. Ligand blotting showed that Cry1Aa toxin bound to the recombinant APN.

  3. [Bites of venomous snakes in Switzerland].

    Science.gov (United States)

    Plate, Andreas; Kupferschmidt, Hugo; Schneemann, Markus

    2016-06-08

    Although snake bites are rare in Europe, there are a constant number of snake bites in Switzerland. There are two domestic venomous snakes in Switzerland: the aspic viper (Vipera aspis) and the common European adder (Vipera berus). Bites from venomous snakes are caused either by one of the two domestic venomous snakes or by an exotic venomous snake kept in a terrarium. Snake- bites can cause both a local and/or a systemic envenoming. Potentially fatal systemic complications are related to disturbances of the hemostatic- and cardiovascular system as well as the central or peripheral nervous system. Beside a symptomatic therapy the administration of antivenom is the only causal therapy to neutralize the venomous toxins.

  4. Measuring Positive Cooperativity Using the Direct ESI-MS Assay. Cholera Toxin B Subunit Homopentamer Binding to GM1 Pentasaccharide

    Science.gov (United States)

    Lin, Hong; Kitova, Elena N.; Klassen, John S.

    2014-01-01

    Direct electrospray ionization mass spectrometry (ESI-MS) assay was used to investigate the stepwise binding of the GM1 pentasaccharide β- D-Gal p-(1→3)-β-D-Gal pNAc-(1→4)[α-D-Neu5Ac-(2→3)]-β- D-Gal p-(1→4)-β-D-Glc p (GM1os) to the cholera toxin B subunit homopentamer (CTB5) and to establish conclusively whether GM1os binding is cooperative. Apparent association constants were measured for the stepwise addition of one to five GM1os to CTB5 at pH 6.9 and 22 °C. The intrinsic association constant, which was established from the apparent association constant for the addition of a single GM1os to CTB5, was found to be (3.2 ± 0.2) × 106 M-1. This is in reasonable agreement with the reported value of (6.4 ± 0.3) × 106 M-1, which was measured at pH 7.4 and 25 °C using isothermal titration calorimetry (ITC). Analysis of the apparent association constants provides direct and unambiguous evidence that GM1os binding exhibits small positive cooperativity. Binding was found to be sensitive to the number of ligand-bound nearest neighbor subunits, with the affinities enhanced by a factor of 1.7 and 2.9 when binding occurs next to one or two ligand-bound subunits, respectively. These findings, which provide quantitative support for the binding model proposed by Homans and coworkers [14], highlight the unique strengths of the direct ESI-MS assay for measuring cooperative ligand binding.

  5. Univalent binding of the Cry1Ab toxin of Bacillus thuringiensis to a conserved structural motif in the cadherin receptor BT-R1.

    Science.gov (United States)

    Griko, Natalya B; Rose-Young, Laura; Zhang, Xuebin; Carpenter, Lindy; Candas, Mehmet; Ibrahim, Mohamed A; Junker, Matthew; Bulla, Lee A

    2007-09-04

    The Cry1Ab toxin produced by Bacillus thuringiensis (Bt) exerts insecticidal action upon binding to BT-R1, a cadherin receptor localized in the midgut epithelium of the tobacco hornworm Manduca sexta [Dorsch, J. A., Candas, M., Griko, N. B., Maaty, W. S., Midboe, E. G., Vadlamudi, R. K., and Bulla, L. A., Jr. (2002) Cry1A toxins of Bacillus thuringiensis bind specifically to a region adjacent to the membrane-proximal extracellular domain of BT-R1 in Manduca sexta: involvement of a cadherin in the entomopathogenicity of Bacillus thuringiensis, Insect Biochem. Mol. Biol. 32, 1025-1036]. BT-R1 represents a family of invertebrate cadherins whose ectodomains (ECs) are composed of multiple cadherin repeats (EC1 through EC12). In the present work, we determined the Cry1Ab toxin binding site in BT-R1 in the context of cadherin structural determinants. Our studies revealed a conserved structural motif for toxin binding that includes two distinct regions within the N- and C-termini of EC12. These regions are characterized by unique sequence signatures that mark the toxin-binding function in BT-R1 as well as in homologous lepidopteran cadherins. Structure modeling of EC12 discloses the conserved motif as a single broad interface that holds the N- and C-termini in close proximity. Binding of toxin to BT-R1, which is univalent, and the subsequent downstream molecular events responsible for cell death depend on the conserved motif in EC12.

  6. Snake Genome Sequencing: Results and Future Prospects.

    Science.gov (United States)

    Kerkkamp, Harald M I; Kini, R Manjunatha; Pospelov, Alexey S; Vonk, Freek J; Henkel, Christiaan V; Richardson, Michael K

    2016-12-01

    Snake genome sequencing is in its infancy-very much behind the progress made in sequencing the genomes of humans, model organisms and pathogens relevant to biomedical research, and agricultural species. We provide here an overview of some of the snake genome projects in progress, and discuss the biological findings, with special emphasis on toxinology, from the small number of draft snake genomes already published. We discuss the future of snake genomics, pointing out that new sequencing technologies will help overcome the problem of repetitive sequences in assembling snake genomes. Genome sequences are also likely to be valuable in examining the clustering of toxin genes on the chromosomes, in designing recombinant antivenoms and in studying the epigenetic regulation of toxin gene expression.

  7. Snake Genome Sequencing: Results and Future Prospects

    Directory of Open Access Journals (Sweden)

    Harald M. I. Kerkkamp

    2016-12-01

    Full Text Available Snake genome sequencing is in its infancy—very much behind the progress made in sequencing the genomes of humans, model organisms and pathogens relevant to biomedical research, and agricultural species. We provide here an overview of some of the snake genome projects in progress, and discuss the biological findings, with special emphasis on toxinology, from the small number of draft snake genomes already published. We discuss the future of snake genomics, pointing out that new sequencing technologies will help overcome the problem of repetitive sequences in assembling snake genomes. Genome sequences are also likely to be valuable in examining the clustering of toxin genes on the chromosomes, in designing recombinant antivenoms and in studying the epigenetic regulation of toxin gene expression.

  8. Snake Genome Sequencing: Results and Future Prospects

    Science.gov (United States)

    Kerkkamp, Harald M. I.; Kini, R. Manjunatha; Pospelov, Alexey S.; Vonk, Freek J.; Henkel, Christiaan V.; Richardson, Michael K.

    2016-01-01

    Snake genome sequencing is in its infancy—very much behind the progress made in sequencing the genomes of humans, model organisms and pathogens relevant to biomedical research, and agricultural species. We provide here an overview of some of the snake genome projects in progress, and discuss the biological findings, with special emphasis on toxinology, from the small number of draft snake genomes already published. We discuss the future of snake genomics, pointing out that new sequencing technologies will help overcome the problem of repetitive sequences in assembling snake genomes. Genome sequences are also likely to be valuable in examining the clustering of toxin genes on the chromosomes, in designing recombinant antivenoms and in studying the epigenetic regulation of toxin gene expression. PMID:27916957

  9. Orthosteric binding of ρ-Da1a, a natural peptide of snake venom interacting selectively with the α1A-adrenoceptor.

    Directory of Open Access Journals (Sweden)

    Arhamatoulaye Maïga

    Full Text Available ρ-Da1a is a three-finger fold toxin from green mamba venom that is highly selective for the α1A-adrenoceptor. This toxin has atypical pharmacological properties, including incomplete inhibition of (3H-prazosin or (125I-HEAT binding and insurmountable antagonist action. We aimed to clarify its mode of action at the α1A-adrenoceptor. The affinity (pKi 9.26 and selectivity of ρ-Da1a for the α1A-adrenoceptor were confirmed by comparing binding to human adrenoceptors expressed in eukaryotic cells. Equilibrium and kinetic binding experiments were used to demonstrate that ρ-Da1a, prazosin and HEAT compete at the α1A-adrenoceptor. ρ-Da1a did not affect the dissociation kinetics of (3H-prazosin or (125I-HEAT, and the IC50 of ρ-Da1a, determined by competition experiments, increased linearly with the concentration of radioligands used, while the residual binding by ρ-Da1a remained stable. The effect of ρ-Da1a on agonist-stimulated Ca(2+ release was insurmountable in the presence of phenethylamine- or imidazoline-type agonists. Ten mutations in the orthosteric binding pocket of the α1A-adrenoceptor were evaluated for alterations in ρ-Da1a affinity. The D106(3.32A and the S188(5.42A/S192(5.46A receptor mutations reduced toxin affinity moderately (6 and 7.6 times, respectively, while the F86(2.64A, F288(6.51A and F312(7.39A mutations diminished it dramatically by 18- to 93-fold. In addition, residue F86(2.64 was identified as a key interaction point for (125I-HEAT, as the variant F86(2.64A induced a 23-fold reduction in HEAT affinity. Unlike the M1 muscarinic acetylcholine receptor toxin MT7, ρ-Da1a interacts with the human α1A-adrenoceptor orthosteric pocket and shares receptor interaction points with antagonist (F86(2.64, F288(6.51 and F312(7.39 and agonist (F288(6.51 and F312(7.39 ligands. Its selectivity for the α1A-adrenoceptor may result, at least partly, from its interaction with the residue F86(2.64, which appears to be important also

  10. Heparin-binding EGF-like growth factor, which acts as the diphtheria toxin receptor, forms a complex with membrane protein DRAP27/CD9, which up-regulates functional receptors and diphtheria toxin sensitivity.

    OpenAIRE

    Iwamoto, R; Higashiyama, S.; Mitamura, T; Taniguchi, N.; Klagsbrun, M; Mekada, E

    1994-01-01

    DRAP27, the monkey homolog of human CD9 antigen (DRAP27/CD9) and diphtheria toxin receptor (DTR) were expressed in mouse L cells. L cells transfected transiently with both DRAP27/CD9 and DTR cDNA bound approximately 10 times more diphtheria toxin (DT) than cells transfected with DTR alone. Stable L cell transfectants expressing both DTR and DRAP27/CD9 (LCH-1 cells) had 15 times more cell surface DT-binding sites and were 20 times more sensitive to DT than were stable L cell transfectants expr...

  11. Bacillus thuringiensis Cry1A toxin-binding glycoconjugates present on the brush border membrane and in the peritrophic membrane of the Douglas-fir tussock moth are peritrophins

    Science.gov (United States)

    Algimantas P. Valaitis; John D. Podgwaite

    2013-01-01

    Bacillus thuringiensis (Bt) Cry1A toxin-binding sites in the Douglas fir tussock moth (DFTM) larval gut were localized using immunofluorescence microscopy. Cry1Aa, Cry1Ab and Cry1Ac all bound strongly to the DFTM peritrophic membrane (PM); weaker binding of the Cry1A toxins was observed along the apical brush border of the midgut epithelium....

  12. Fighting Cholera One-on-One: The Development and Efficacy of Multivalent Cholera-Toxin-Binding Molecules.

    Science.gov (United States)

    Zuilhof, Han

    2016-02-16

    A series of diseases, ranging from cholera via travelers' diarrhea to hamburger disease, are caused by bacterially produced toxic proteins. In particular, a toxic protein unit is brought into the host cell upon binding to specific membrane-bound oligosaccharides on the host cell membrane. For example, the protein that causes cholera, cholera toxin (CT), has five identical, symmetrically placed binding pockets (B proteins), on top of which the toxic A protein resides. A promising strategy to counteract the devastating biological effects of this AB5 protein involves the development of inhibitors that can act as mimics of membrane-bound GM1 molecules, i.e., that can bind CT strongly and selectively. To reach this goal, two features are essential: First of all, the inhibitor should display oligosaccharides that resemble as much as possible the naturally occurring cell-surface pentasaccharide onto which CT normally binds, the so-called GM1 sugar (the oligosaccharide part of which is then labeled GM1os). Second, the inhibitor should be able to bind CT via multivalent interactions so as to bind CT as strongly as possible to allow for a real competition with the cell-membrane-bound GM1 molecules. In this Account, we present elements of the path that leads to strong CT inhibition by outlining the roles of multivalency and the development and use of GM1 mimics. First, multivalency effects were investigated using "sugar-coated" platforms, ranging from dendritic structures with up to eight oligosaccharides to platforms that mimicked the fivefold symmetry of CT itself. The latter goal was reached either via synthetic scaffolds like corannulene or calix[5]arene or via the development of a neolectin CT mimic that itself carries five GM1os groups. Second, the effect of the nature of the oligosaccharide appended to this platform was investigated via the use of oligosaccharides of increasing complexity, from galactose and lactose to the tetrasaccharide GM2os and eventually to GM1os

  13. Inhibition of Binding of the AB5-Type Enterotoxins LT-I and Cholera Toxin to Ganglioside GM1 by Galactose-Rich Dietary Components

    NARCIS (Netherlands)

    Becker, P.M.; Widjaja-Greefkes, H.C.A.; Wikselaar, van P.G.

    2010-01-01

    Cholera, travelers' diarrhea, or colibacillosis in pigs can possibly be prevented or attenuated by dietary provision of competitive inhibitors that react with the GM1-binding sites of the enterotoxins cholera toxin (CT), human Escherichia coli heat-labile enterotoxin of serogroup I (LTh-I), and

  14. Effects of clay on toxin binding capacity, ruminal fermentation, diet digestibility, and growth of steers fed high-concentrate diets.

    Science.gov (United States)

    Antonelo, D S; Lancaster, N A; Melnichenko, S; Muegge, C R; Schoonmaker, J P

    2017-10-01

    Three experiments were conducted to determine the effect of increasing concentrations of a smectite clay on toxin binding capacity, ruminal fermentation, diet digestibility, and growth of feedlot cattle. In Exp. 1, 72 Angus × Simmental steers were blocked by BW (395 ± 9.9 kg) and randomly allotted to 3 treatments (4 pens/treatment and 6 steers/pen) to determine the effects of increasing amounts of clay (0, 1, or 2%) on performance. The clay was top-dressed on an 80% concentrate diet at a rate of 0, 113, or 226 g/steer daily to achieve the 0, 1, and 2% treatments, respectively. Steers were slaughtered at a target BW of 606 kg. In Exp. 2, 6 steers (596 ± 22.2 kg initial BW) were randomly allotted to the same 3 treatments in a replicated 3 × 3 Latin square design (21-d periods) to determine the effects of increasing amounts of clay on ruminal pH, VFA, and nutrient digestibility. In Exp. 3, 150 mg of clay was incubated in 10 mL of rumen fluid with 3 incremental concentrations (6 replicates per concentration) of aflatoxin B (AFB) or ergotamine tartate (ET) to determine binding capacity. During the first 33-d period, there was a quadratic effect of clay on ADG ( clay and then decreasing from 1 to 2% clay. However, during the second 30-d period, clay linearly decreased ADG and G:F ( ≤ 0.03) and overall ADG, DMI, and G:F were not impacted ( ≥ 0.46). Clay linearly decreased marbling score ( = 0.05). Hepatic enzyme activity did not differ among treatments on d 0 or at slaughter ( ≥ 0.15). Clay linearly decreased ruminal lactate and propionate, linearly increased formate and the acetate:propionate ratio ( ≤ 0.04), and tended ( = 0.07) to linearly increase butyrate. Clay tended to linearly increase ( = 0.06) OM and CP apparent digestibility. Ruminal pH, urine pH, and other digestibility measures did not differ among treatments ( ≥ 0.15). Clay was able to effectively bind AFB and ET at concentrations above the normal physiological range (52 and 520 μg/mL), but

  15. Phospholipases A2 isolated from Micrurus lemniscatus coral snake venom: behavioral, electroencephalographic, and neuropathological aspects.

    Science.gov (United States)

    Oliveira, D A; Harasawa, C; Seibert, C S; Casais e Silva, L L; Pimenta, D C; Lebrun, I; Sandoval, M R L

    2008-03-28

    The present study evaluated four phospholipase A2 (PLA2) (Mlx-8, Mlx-9, Mlx-11 and Mlx-12) isolated from Micrurus lemniscatus snake venom (Elapidae). The effects of intrahippocampal administration of these toxins have been determined on behavior, electroencephalography, and neuronal degeneration in rats. These four PLA2 toxins induced motor and EEG alterations in a dose-dependent manner. Behavioral convulsions were characterized by clonic movements and were often accompanied by EEG alterations. Mlx toxins were convulsive but weakly epileptogenic, since low rates of seizure discharges were observed in EEG records. Neuronal injury seemed to depend on the dose of the toxin used. The highest doses of toxins caused severe intoxication and death of some animals. The injury of hippocampal cells was characterized by massive neuronal loss and hippocampal gliosis. A high occurrence of compulsive scratching was observed. Moreover, the onset of seizures induced by Mlx toxins was markedly delayed. The similarities between the effects of Mlx PLA2s and those isolated from other Elapidae snakes venoms suggest that their toxicity are probably due to their specific binding to neuronal membranes and to the catalysis of phospholipid hydrolysis, producing lysophospholipids and fatty acids. These compounds likely disturb the membrane conformation, causing a marked increase in the release of neurotransmitters and concurrent inhibition of vesicle fission and recycling. These toxins can be a useful tool to investigate properties of endogenous secretory PLA2s and therefore may be important both to study mechanisms involved in neurotransmitter release at nerve terminals and to explain the convulsive properties of PLA2s toxins.

  16. Native or Proteolytically Activated NanI Sialidase Enhances the Binding and Cytotoxic Activity of Clostridium perfringens Enterotoxin and Beta Toxin.

    Science.gov (United States)

    Theoret, James R; Li, Jihong; Navarro, Mauricio A; Garcia, Jorge P; Uzal, Francisco A; McClane, Bruce A

    2018-01-01

    Many Clostridium perfringens strains produce NanI as their major sialidase. Previous studies showed that NanI could potentiate C. perfringens epsilon toxin cytotoxicity by enhancing the binding of this toxin to host cells. The present study first determined that NanI exerts similar cytotoxicity-enhancing effects on C. perfringens enterotoxin and beta toxin, which are also important toxins for C. perfringens diseases (enteritis and enterotoxemia) originating in the gastrointestinal (GI) tract. Building upon previous work demonstrating that purified trypsin can activate NanI activity, this study next determined that purified chymotrypsin or mouse intestinal fluids can also activate NanI activity. Amino acid sequencing then showed that this effect involves the N-terminal processing of the NanI protein. Recombinant NanI (rNanI) species corresponding to major chymotrypsin- or small intestinal fluid-generated NanI fragments possessed more sialidase activity than did full-length rNanI, further supporting the proteolytic activation of NanI activity. rNanI species corresponding to proteolysis products also promoted the cytotoxic activity and binding of enterotoxin and beta toxin more strongly than did full-length rNanI. Since enterotoxin and beta toxin are produced in the intestines during human and animal disease, these findings suggest that intestinal proteases may enhance NanI activity, which in turn could further potentiate the activity of intestinally active toxins during disease. Coupling these new results with previous findings demonstrating that NanI is important for the adherence of C. perfringens to enterocyte-like cells, NanI sialidase is now emerging as a potential auxiliary virulence factor for C. perfringens enteritis and enterotoxemia. Copyright © 2017 American Society for Microbiology.

  17. Aminopeptidase N isoforms from the midgut of Bombyx mori and Plutella xylostella -- their classification and the factors that determine their binding specificity to Bacillus thuringiensis Cry1A toxin.

    Science.gov (United States)

    Nakanishi, Kazuko; Yaoi, Katsuro; Nagino, Yasushi; Hara, Hirotaka; Kitami, Madoka; Atsumi, Shogo; Miura, Nami; Sato, Ryoichi

    2002-05-22

    Novel aminopeptidase N (APN) isoform cDNAs, BmAPN3 and PxAPN3, from the midguts of Bombyx mori and Plutella xylostella, respectively, were cloned, and a total of eight APN isoforms cloned from B. mori and P. xylostella were classified into four classes. Bacillus thuringiensis Cry1Aa and Cry1Ab toxins were found to bind to specific APN isoforms from the midguts of B. mori and P. xylostella, and binding occurred with fragments that corresponded to the BmAPN1 Cry1Aa toxin-binding region of each APN isoform. The results suggest that APN isoforms have a common toxin-binding region, and that the apparent specificity of Cry1Aa toxin binding to each intact APN isoform seen in SDS-PAGE is determined by factors such as expression level in conjunction with differences in binding affinity.

  18. Comparison of high-resolution structures of the diphtheria toxin repressor in complex with cobalt and zinc at the cation-anion binding site.

    OpenAIRE

    Pohl, E.; Qui, X.; Must, L. M.; Holmes, R K; Hol, W G

    1997-01-01

    The diphtheria toxin repressor (DtxR) from Corynebacterium diphtheriae is a divalent-metal activated repressor of chromosomal genes responsible for siderophore-mediated iron-uptake and of a gene on several corynebacteriophages that encodes diphtheria toxin. Even though DtxR is the best characterized iron-dependent repressor to date, numerous key properties of the protein still remain to be explained. One is the role of the cation-anion pair discovered in its first metal-binding site. A second...

  19. Comparisons of Native and Chimeric Shiga Toxins Indicate that the Binding Subunit Dictates Degree of Toxicity

    Science.gov (United States)

    2014-03-17

    proteinuria , chronic kidney disease, and decreased glomerular filtration rate (GFR). Cerebral endothelial involvement is a serious HUS sequela...Stx2a cell (HK-2) Differential induction of ER stress response High membrane Gb3 ( 150 ) Stx 1 a B subunit to ER and lysosome Human renal glomerular... 150 ; 165; 287) of Stxla and Stx2a holotoxins. As stated previously, Stxla and Stx2a preferentially bind Gb3 FA chains of different lengths; Stx 1 a

  20. High prevalence of subclass-specific binding and neutralizing antibodies against Clostridium difficile toxins in adult cystic fibrosis sera: possible mode of immunoprotection against symptomatic C. difficile infection

    Directory of Open Access Journals (Sweden)

    Monaghan TM

    2017-07-01

    Full Text Available Tanya M Monaghan,1 Ola H Negm,2,3 Brendon MacKenzie,4 Mohamed R Hamed,2,3 Clifford C Shone,5 David P Humphreys,4 K Ravi Acharya,6 Mark H Wilcox7 1Nottingham Digestive Diseases Centre, NIHR Nottingham Digestive Diseases Biomedical Research Unit, School of Medicine, University of Nottingham, Nottingham, 2Breast Surgery Group, Division of Medical Sciences and Graduate Entry Medicine, School of Medicine, Queen’s Medical Centre, University of Nottingham, Nottingham, UK; 3Medical Microbiology and Immunology Department, Faculty of Medicine, Mansoura University, Mansoura, Egypt; 4Antibody Biology, UCB-New Medicines, UCB Celltech, Slough, UK; 5Toxins Group, National Infection Service, Public Health England, Salisbury, UK; 6Department of Biology and Biochemistry, University of Bath, Bath, UK; 7Leeds Institute of Biomedical and Clinical Sciences, University of Leeds, Leeds, UK Objectives: Despite multiple risk factors and a high rate of colonization for Clostridium difficile, the occurrence of C. difficile infection in patients with cystic fibrosis is rare. The aim of this study was to compare the prevalence of binding C. difficile toxin-specific immunoglobulin (IgA, IgG and anti-toxin neutralizing antibodies in the sera of adults with cystic fibrosis, symptomatic C. difficile infection (without cystic fibrosis and healthy controls. Methods: Subclass-specific IgA and IgG responses to highly purified whole C. difficile toxins A and B (toxinotype 0, strain VPI 10463, ribotype 087, toxin B from a C. difficile toxin-B-only expressing strain (CCUG 20309 and precursor form of B fragment of binary toxin, pCDTb, were determined by protein microarray. Neutralizing antibodies to C. difficile toxins A and B were evaluated using a Caco-2 cell-based neutralization assay. Results: Serum IgA anti-toxin A and B levels and neutralizing antibodies against toxin A were significantly higher in adult cystic fibrosis patients (n=16 compared with healthy controls (n=17 and

  1. Inactivation and fragmentation of lectin from Bothrops leucurus snake venom by gamma irradiation

    Science.gov (United States)

    Nunes, E. S.; Souza, M. A. A.; Vaz, A. F. M.; Coelho, L. C. B. B.; Aguiar, J. S.; Silva, T. G.; Guarnieri, M. C.; Melo, A. M. M. A.; Oliva, M. L. V.; Correia, M. T. S.

    2012-04-01

    Gamma radiation alters the molecular structure of biomolecules and is able to mitigate the action of snake venoms and their isolated toxins. The effect of γ-radiation on the folding of Bothrops lecurus venom lectin was measured by a hemagglutinating assay, intrinsic and bis-ANS fluorescence. Intrinsic and bis-ANS fluorescence analyses indicated that irradiation caused unfolding followed by aggregation of the lectin. Our results suggest that irradiation can lead to significant changes in the protein structure, which may promote the loss of its binding property and toxic action.

  2. Colistin inhibits E. coli O157:H7 Shiga-like toxin release, binds endotoxins and protects Vero cells.

    Science.gov (United States)

    Percivalle, Elena; Monzillo, Vincenzina; Pauletto, Alessandro; Marone, Piero; Imberti, Roberto

    2016-04-01

    The role of antibiotics in the treatment of Shiga-like toxin (Stx)-producing E. coli infection is still controversial. This study investigated the effects of colistin on Vero cell cytotoxicity caused by the enterohemorrhagic EC O157:H7, and the effects of colistin on Stx and endotoxin release by EC O157:H7. Vero cells were incubated with supernatant collected from EC O157:H7 cultured for 18 h without (control) or with various concentrations of colistin. In the absence of colistin, Vero cell viability after 48 h was 29.1±6.5%. Under the same conditions, the overnight presence of colistin reduced cytotoxicity to Vero cells (viability: 97±3.5 to 56.5±14.4% for colistin concentrations ≥MIC). Sub-MIC concentrations of colistin also provided partial protection (viability: 38.8±12.5 to 36.6±14% for 0.125 and 0.06 mcg/ml colistin, respectively). Endotoxins contributed to the cytotoxic effects on Vero cells since lower but still significant protection was observed when colistin was added directly to the supernatant collected from cultures of untreated EC O157:H7. Colistin reduced Stx release in a concentration-dependent manner, also at sub-MIC concentrations. Coincubation of the supernatant from EC O157:H7 cultures with colistin markedly reduced the endotoxin concentration at all doses investigated. In conclusion, colistin protects Vero cells from EC O157:H7 at supra- and sub-MIC concentrations by inhibiting Stx release and binding endotoxins. Colistin might be a valuable treatment for clinically severe forms of EC O157:H7 infection.

  3. Botulinum Toxin

    Science.gov (United States)

    2009-01-01

    intercostal muscle (Hilmas, unpublished data). All serotypes showed a similar ability to produce complete muscular paralysis in ex vivo human intercostal...routes of exposure include, in order of descending frequency: dysphagia, xerostomia, diplopia, dysarthria, fatigue , ptosis of the eyelids...Medical and Public Health Manage- ment. JAMA 285: 1059-70. Bakry, N., Kamata, Y., Simpson, L. (1997). Expression of botu- linum toxin binding sites in

  4. Comparison of sea snake (Hydrophiidae) neurotoxin to cobra (Naja) neurotoxin.

    Science.gov (United States)

    Komori, Yumiko; Nagamizu, Masaya; Uchiya, Kei-Ichi; Nikai, Toshiaki; Tu, Anthony T

    2009-12-01

    Both sea snakes and cobras have venoms containing postsynaptic neurotoxins. Comparison of the primary structures indicates many similarities, especially the positions of the four disulfide bonds. However, detailed examination reveals differences in several amino acid residues. Amino acid sequences of sea snake neurotoxins were determined, and then compared to cobra neurotoxins by computer modeling. This allowed for easy comparison of the similarities and differences between the two types of postsynaptic neurotoxins. Comparison of computer models for the toxins of sea snakes and cobra will reveal the three dimensional difference of the toxins much clearer than the amino acid sequence alone.

  5. Holotrichia oblita Midgut Proteins That Bind to Bacillus thuringiensis Cry8-Like Toxin and Assembly of the H. oblita Midgut Tissue Transcriptome.

    Science.gov (United States)

    Jiang, Jian; Huang, Ying; Shu, Changlong; Soberón, Mario; Bravo, Alejandra; Liu, Chunqing; Song, Fuping; Lai, Jinsheng; Zhang, Jie

    2017-06-15

    The Bacillus thuringiensis strain HBF-18 (CGMCC 2070), containing two cry genes (cry8-like and cry8Ga), is toxic to Holotrichia oblita larvae. Both Cry8-like and Cry8Ga proteins are active against this insect pest, and Cry8-like is more toxic. To analyze the characteristics of the binding of Cry8-like and Cry8Ga proteins to brush border membrane vesicles (BBMVs) in H. oblita larvae, binding assays were conducted with a fluorescent DyLight488-labeled Cry8-like toxin. The results of saturation binding assays demonstrated that Cry8-like bound specifically to binding sites on BBMVs from H. oblita, and heterologous competition assays revealed that Cry8Ga shared binding sites with Cry8-like. Furthermore, Cry8-like-binding proteins in the midgut from H. oblita larvae were identified by pulldown assays and liquid chromatography-tandem mass spectrometry (LC-MS/MS). In addition, the H. oblita midgut transcriptome was assembled by high-throughput RNA sequencing and used for identification of Cry8-like-binding proteins. Eight Cry8-like-binding proteins were obtained from pulldown assays conducted with BBMVs. The LC-MS/MS data for these proteins were successfully matched with the H. oblita transcriptome, and BLASTX results identified five proteins as serine protease, transferrin-like, uncharacterized protein LOC658236 of Tribolium castaneum, ATPase catalytic subunit, and actin. These identified Cry8-like-binding proteins were different from those confirmed previously as receptors for Cry1A proteins in lepidopteran insect species, such as aminopeptidase, alkaline phosphatase, and cadherin.IMPORTANCEHolotrichia oblita is one of the main soil-dwelling pests in China. The larvae damage the roots of crops, resulting in significant yield reductions and economic losses. H. oblita is difficult to control, principally due to its soil-dwelling habits. In recent years, some Cry8 toxins from Bacillus thuringiensis were shown to be active against this pest. Study of the mechanism of action

  6. Characterization of a Mutant Diphtheria Toxin that is Defective in Binding to Cell Membrane Receptors on Vero Cells

    Science.gov (United States)

    1982-08-13

    the primary injury produced by diphtheria toxin is the inhibition of protein synthesis In eucaryotic cells . Because early studies of diphtheria...different animal species were reported (58, 181), yet the protein-synthesizing systems in cell - free extracts from all eucaryotic cells are equally...the translocation of toxin to the cell cytosol. Macromolecules which possess a hydrophobic domain can penetrate the lipid bilayer of eucaryotic

  7. C. difficile 630Δerm Spo0A regulates sporulation, but does not contribute to toxin production, by direct high-affinity binding to target DNA.

    Directory of Open Access Journals (Sweden)

    Katharina E Rosenbusch

    Full Text Available Clostridium difficile is a Gram positive, anaerobic bacterium that can form highly resistant endospores. The bacterium is the causative agent of C. difficile infection (CDI, for which the symptoms can range from a mild diarrhea to potentially fatal pseudomembranous colitis and toxic megacolon. Endospore formation in Firmicutes, including C. difficile, is governed by the key regulator for sporulation, Spo0A. In Bacillus subtilis, this transcription factor is also directly or indirectly involved in various other cellular processes. Here, we report that C. difficile Spo0A shows a high degree of similarity to the well characterized B. subtilis protein and recognizes a similar binding sequence. We find that the laboratory strain C. difficile 630Δerm contains an 18bp-duplication near the DNA-binding domain compared to its ancestral strain 630. In vitro binding assays using purified C-terminal DNA binding domain of the C. difficile Spo0A protein demonstrate direct binding to DNA upstream of spo0A and sigH, early sporulation genes and several other putative targets. In vitro binding assays suggest that the gene encoding the major clostridial toxin TcdB may be a direct target of Spo0A, but supernatant derived from a spo0A negative strain was no less toxic towards Vero cells than that obtained from a wild type strain, in contrast to previous reports. These results identify for the first time direct (putative targets of the Spo0A protein in C. difficile and make a positive effect of Spo0A on production of the large clostridial toxins unlikely.

  8. Dictionary Snakes

    DEFF Research Database (Denmark)

    Dahl, Anders Bjorholm; Dahl, Vedrana Andersen

    2014-01-01

    for image segmentation that operates without training data. Our method is based on a probabilistic dictionary of image patches coupled with a deformable model inspired by snakes and active contours without edges. We separate the image into two classes based on the information provided by the evolving curve...

  9. Deficiency in Calcium-Binding Protein S100A4 Impairs the Adjuvant Action of Cholera Toxin

    Directory of Open Access Journals (Sweden)

    Jia-Bin Sun

    2017-09-01

    Full Text Available The calcium-binding protein S100A4 has been described to promote pathological inflammation in experimental autoimmune and inflammatory disorders and in allergy and to contribute to antigen presentation and antibody response after parenteral immunization with an alum-adjuvanted antigen. In this study, we extend these findings by demonstrating that mice lacking S100A4 have a defective humoral and cellular immune response to mucosal (sublingual immunization with a model protein antigen [ovalbumin (OVA] given together with the strong mucosal adjuvant cholera toxin (CT, and that this impairment is due to defective adjuvant-stimulated antigen presentation by antigen-presenting cells. In comparison to wild-type (WT mice, mice genetically lacking S100A4 had reduced humoral and cellular immune responses after immunization with OVA plus CT, including a complete lack of detectable germinal center reaction. Further, when stimulated in vitro with OVA plus CT, S100A4−/− dendritic cells (DCs showed impaired responses in several CT-stimulated immune regulatory molecules including the co-stimulatory molecule CD86, inflammasome-associated caspase-1 and IL-1β. Coculture of OVA-specific OT-II T cells with S100A4−/− DCs that had been pulse incubated with OVA plus CT resulted in impaired OT-II T cell proliferation and reduced production of Th1, Th2, and Th17 cytokines compared to similar cocultures with WT DCs. In accordance with these findings, transfection of WT DCs with S100A4-targeting small interfering RNA (siRNA but not mock-siRNA resulted in significant reductions in the expression of caspase-1 and IL-1β as well as CD86 in response to CT. Importantly, also engraftment of WT DCs into S100A4−/− mice effectively restored the immune response to immunization in the recipients. In conclusion, our results demonstrate that deficiency in S100A4 has a strong impact on the development of both humoral and cellular immunity after mucosal immunization using CT

  10. Binding of superantigen toxins into the CD28 homodimer interface is essential for induction of cytokine genes that mediate lethal shock.

    Directory of Open Access Journals (Sweden)

    Gila Arad

    2011-09-01

    Full Text Available Bacterial superantigens, a diverse family of toxins, induce an inflammatory cytokine storm that can lead to lethal shock. CD28 is a homodimer expressed on T cells that functions as the principal costimulatory ligand in the immune response through an interaction with its B7 coligands, yet we show here that to elicit inflammatory cytokine gene expression and toxicity, superantigens must bind directly into the dimer interface of CD28. Preventing access of the superantigen to CD28 suffices to block its lethality. Mice were protected from lethal superantigen challenge by short peptide mimetics of the CD28 dimer interface and by peptides selected to compete with the superantigen for its binding site in CD28. Superantigens use a conserved β-strand/hinge/α-helix domain of hitherto unknown function to engage CD28. Mutation of this superantigen domain abolished inflammatory cytokine gene induction and lethality. Structural analysis showed that when a superantigen binds to the T cell receptor on the T cell and major histocompatibility class II molecule on the antigen-presenting cell, CD28 can be accommodated readily as third superantigen receptor in the quaternary complex, with the CD28 dimer interface oriented towards the β-strand/hinge/α-helix domain in the superantigen. Our findings identify the CD28 homodimer interface as a critical receptor target for superantigens. The novel role of CD28 as receptor for a class of microbial pathogens, the superantigen toxins, broadens the scope of pathogen recognition mechanisms.

  11. Crystal Structures of the Staphylococcal Toxin SSL5 in Complex With Sialyl-Lewis X Reveal a Conserved Binding Site That Shares Common Features With Viral And Bacterial Sialic Acid-Binding Proteins

    Energy Technology Data Exchange (ETDEWEB)

    Baker, H.M.; Basu, I.; Chung, M.C.; Caradoc-Davies, T.; Fraser, J.D.; Baker, E.N.

    2009-06-02

    Staphylococcus aureus is a significant human pathogen. Among its large repertoire of secreted toxins is a group of staphylococcal superantigen-like proteins (SSLs). These are homologous to superantigens but do not have the same activity. SSL5 is shown here to bind to human granulocytes and to the cell surface receptors for human IgA (Fc alphaRI) and P-selectin [P-selectin glycoprotein ligand-1 (PSGL-1)] in a sialic acid (Sia)-dependent manner. Co-crystallization of SSL5 with the tetrasaccharide sialyl Lewis X (sLe(X)), a key determinant of PSGL-1 binding to P-selectin, led to crystal structures of the SSL5-sLe(X) complex at resolutions of 1.65 and 2.75 A for crystals at two pH values. In both structures, sLe(X) bound to a specific site on the surface of the C-terminal domain of SSL5 in a conformation identical with that bound by P-selectin. Conservation of the key carbohydrate binding residues indicates that this ability to bind human glycans is shared by a substantial subgroup of the SSLs, including SSL2, SSL3, SSL4, SSL5, SSL6, and SSL11. This indicates that the ability to target human glycans is an important property of this group of toxins. Structural comparisons also showed that the Sia binding site in SSL5 contains a substructure that is shared by other Sia binding proteins from bacteria as well as viruses and represents a common binding motif.

  12. Nanodiscs for immobilization of lipid bilayers and membrane receptors: kinetic analysis of cholera toxin binding to a glycolipid receptor

    DEFF Research Database (Denmark)

    Borch, Jonas; Torta, Federico; Sligar, Stephen G

    2008-01-01

    nanodiscs and their incorporated membrane receptors can be attached to surface plasmon resonance sensorchips and used to measure the kinetics of the interaction between soluble molecules and membrane receptors inserted in the bilayer of nanodiscs. Cholera toxin and its glycolipid receptor G(M1) constitute...... partner cholera toxin B subunit to the receptor with the sensorchip-based surface plasmon resonance (SPR) technology. The measured stoichiometric and kinetic values of the interaction are in agreement with those reported by previous studies, thus providing proof-of-principle that nanodiscs can be employed...

  13. Molecular Docking Studies and Anti−Snake Venom Metalloproteinase Activity of Thai Mango Seed Kernel Extract

    Directory of Open Access Journals (Sweden)

    Pimolpan Pithayanukul

    2009-08-01

    Full Text Available Snakebite envenomations cause severe local tissue necrosis and the venom metalloproteinases are thought to be the key toxins involved. In this study, the ethanolic extract from seed kernels of Thai mango (Mangifera indica L. cv. ‘Fahlun’ (Anacardiaceae and its major phenolic principle (pentagalloylglucopyranose exhibited potent and dose−dependent inhibitory effects on the caseinolytic and fibrinogenolytic activities of Malayan pit viper and Thai cobra venoms in in vitro tests. molecular docking studies revealed that the binding orientations of the phenolic principles were in the binding pockets of snake venom metalloproteinases (SVMPs. The phenolic principles could form hydrogen bonds with the three histidine residues in the conserved zinc−binding motif and could chelate the Zn2+ atom of the SVMPs, which could potentially result in inhibition of the venom enzymatic activities and thereby inhibit tissue necrosis.

  14. Molecular docking studies and anti-snake venom metalloproteinase activity of Thai mango seed kernel extract.

    Science.gov (United States)

    Pithayanukul, Pimolpan; Leanpolchareanchai, Jiraporn; Saparpakorn, Patchreenart

    2009-08-27

    Snakebite envenomations cause severe local tissue necrosis and the venom metalloproteinases are thought to be the key toxins involved. In this study, the ethanolic extract from seed kernels of Thai mango (Mangifera indica L. cv. 'Fahlun') (Anacardiaceae) and its major phenolic principle (pentagalloylglucopyranose) exhibited potent and dose-dependent inhibitory effects on the caseinolytic and fibrinogenolytic activities of Malayan pit viper and Thai cobra venoms in in vitro tests. molecular docking studies revealed that the binding orientations of the phenolic principles were in the binding pockets of snake venom metalloproteinases (SVMPs). The phenolic principles could form hydrogen bonds with the three histidine residues in the conserved zinc-binding motif and could chelate the Zn(2+) atom of the SVMPs, which could potentially result in inhibition of the venom enzymatic activities and thereby inhibit tissue necrosis.

  15. MmTX1 and MmTX2 from coral snake venom potently modulate GABAA receptor activity.

    Science.gov (United States)

    Rosso, Jean-Pierre; Schwarz, Jürgen R; Diaz-Bustamante, Marcelo; Céard, Brigitte; Gutiérrez, José M; Kneussel, Matthias; Pongs, Olaf; Bosmans, Frank; Bougis, Pierre E

    2015-02-24

    GABAA receptors shape synaptic transmission by modulating Cl(-) conductance across the cell membrane. Remarkably, animal toxins that specifically target GABAA receptors have not been identified. Here, we report the discovery of micrurotoxin1 (MmTX1) and MmTX2, two toxins present in Costa Rican coral snake venom that tightly bind to GABAA receptors at subnanomolar concentrations. Studies with recombinant and synthetic toxin variants on hippocampal neurons and cells expressing common receptor compositions suggest that MmTX1 and MmTX2 allosterically increase GABAA receptor susceptibility to agonist, thereby potentiating receptor opening as well as desensitization, possibly by interacting with the α(+)/β(-) interface. Moreover, hippocampal neuron excitability measurements reveal toxin-induced transitory network inhibition, followed by an increase in spontaneous activity. In concert, toxin injections into mouse brain result in reduced basal activity between intense seizures. Altogether, we characterized two animal toxins that enhance GABAA receptor sensitivity to agonist, thereby establishing a previously unidentified class of tools to study this receptor family.

  16. Protection against Shiga Toxins

    Directory of Open Access Journals (Sweden)

    Simona Kavaliauskiene

    2017-02-01

    Full Text Available Shiga toxins consist of an A-moiety and five B-moieties able to bind the neutral glycosphingolipid globotriaosylceramide (Gb3 on the cell surface. To intoxicate cells efficiently, the toxin A-moiety has to be cleaved by furin and transported retrogradely to the Golgi apparatus and to the endoplasmic reticulum. The enzymatically active part of the A-moiety is then translocated to the cytosol, where it inhibits protein synthesis and in some cell types induces apoptosis. Protection of cells can be provided either by inhibiting binding of the toxin to cells or by interfering with any of the subsequent steps required for its toxic effect. In this article we provide a brief overview of the interaction of Shiga toxins with cells, describe some compounds and conditions found to protect cells against Shiga toxins, and discuss whether they might also provide protection in animals and humans.

  17. Snakes antibodies.

    Science.gov (United States)

    Gambón-Deza, Francisco; Sánchez-Espinel, Christian; Mirete-Bachiller, Serafín; Magadán-Mompó, Susana

    2012-09-01

    Immunoglobulins are basic molecules of the immune system of vertebrates. In previous studies we described the immunoglobulins found in two squamata reptiles, Anolis carolinensis and Eublepharis macularius. Snakes are squamata reptiles too but they have undergone an extreme evolutionary process. We therefore wanted to know how these changes affected their immunoglobulin coding genes. To perform this analysis we studied five snake transcriptomes and two genome draft sequences. Sequences coding for immunoglobulin M (IgM), immunoglobulin D (IgD) and two classes of immunoglobulin Y (IgY - named IgYa and IgYb-) were found in all of them. Moreover, the Thamnophis elegans transcriptome and Python molurus genome draft sequences showed a third class of IgY, the IgYc, whose constant region only presents three domains and lacks the CH2. All data suggest that the IgYb is the evolutionary origin of this IgYc. An exhaustive search of the light chains were carried out, being lambda the only light chain found in snakes. The results provide a clear picture of the immunoglobulins present in the suborder Serpentes. Copyright © 2012 Elsevier Ltd. All rights reserved.

  18. Natural toxins and their therapeutic potential.

    Science.gov (United States)

    Kapoor, V K

    2010-03-01

    Plants have been extensively investigated for exploring their therapeutic potentials, but there are comparatively scanty reports on drugs derived from animal kingdom, except for hormones. During last decade, the toxins that are used for defense by the animals, have been isolated and found useful tools for physiological and pharmacological studies, besides giving valuable leads to drug development. Toxins with interesting results have been isolated from the venoms of snakes, scorpions, spiders, snails, lizards, frogs and fish. The present review describe about some toxins as drugs and their biological activities. Some fungal, bacterial and marine toxins have also been covered in this article.

  19. Field-Evolved Mode 1 Resistance of the Fall Armyworm to Transgenic Cry1Fa-Expressing Corn Associated with Reduced Cry1Fa Toxin Binding and Midgut Alkaline Phosphatase Expression.

    Science.gov (United States)

    Jakka, Siva R K; Gong, Liang; Hasler, James; Banerjee, Rahul; Sheets, Joel J; Narva, Kenneth; Blanco, Carlos A; Jurat-Fuentes, Juan L

    2015-12-04

    Insecticidal protein genes from the bacterium Bacillus thuringiensis (Bt) are expressed by transgenic Bt crops (Bt crops) for effective and environmentally safe pest control. The development of resistance to these insecticidal proteins is considered the most serious threat to the sustainability of Bt crops. Resistance in fall armyworm (Spodoptera frugiperda) populations from Puerto Rico to transgenic corn producing the Cry1Fa insecticidal protein resulted, for the first time in the United States, in practical resistance, and Bt corn was withdrawn from the local market. In this study, we used a field-collected Cry1Fa corn-resistant strain (456) of S. frugiperda to identify the mechanism responsible for field-evolved resistance. Binding assays detected reduced Cry1Fa, Cry1Ab, and Cry1Ac but not Cry1Ca toxin binding to midgut brush border membrane vesicles (BBMV) from the larvae of strain 456 compared to that from the larvae of a susceptible (Ben) strain. This binding phenotype is descriptive of the mode 1 type of resistance to Bt toxins. A comparison of the transcript levels for putative Cry1 toxin receptor genes identified a significant downregulation (>90%) of a membrane-bound alkaline phosphatase (ALP), which translated to reduced ALP protein levels and a 75% reduction in ALP activity in BBMV from 456 compared to that of Ben larvae. We cloned and heterologously expressed this ALP from susceptible S. frugiperda larvae and demonstrated that it specifically binds with Cry1Fa toxin. This study provides a thorough mechanistic description of field-evolved resistance to a transgenic Bt crop and supports an association between resistance and reduced Cry1Fa toxin binding and levels of a putative Cry1Fa toxin receptor, ALP, in the midguts of S. frugiperda larvae. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  20. Snake classification from images

    OpenAIRE

    James, Alex.

    2017-01-01

    Incorrect snake identification from the observable visual traits is a major reason of death resulting from snake bites. So far no automatic classification method has been proposed to distinguish snakes by deciphering the taxonomy features of snake for the two major species of snakes i.e. Elapidae and Viperidae. We present a parallel processed inter-feature product similarity fusion based automatic classification of Spectacled Cobra, Russel's Viper, King Cobra, Common Krait, Saw Scaled Viper, ...

  1. Dangerous snakes, deadly snakes and medically important snakes

    OpenAIRE

    Silva, Anjana

    2013-01-01

    This correspondence argues that the dangerousness of a venomous snake species is not solely determined by the venom characteristics or the lethality of the snake, and recognizes that medical importance comprises a key variable as well. The medical importance of a snake is determined by several factors ? including frequency of medical attention after a bite, local or systemic envenomation provoked by the bite, fatal bites, long term consequences, availability of antivenom therapy as well as th...

  2. Microimaging of Bacillus thuringiensis Toxin-binding proteins in gypsy moth larval gut using confocal fluorescence microscopy

    Science.gov (United States)

    Daniel J. Krofcheck; Algimantas P. Valaitis

    2010-01-01

    After ingestion by susceptible insect larvae, Bacillus thuringiensis (Bt) insecticidal proteins bind to the brush border membranes of gut epithelial cells and disrupt the integrity of the plasma membrane by forming...

  3. Diversity of toxic components from the venom of the evolutionarily distinct black whip snake, Demansia vestigiata.

    Science.gov (United States)

    St Pierre, Liam; Birrell, Geoff W; Earl, Stephen T; Wallis, Tristan P; Gorman, Jeffrey J; de Jersey, John; Masci, Paul P; Lavin, Martin F

    2007-08-01

    Included among the more than 300 species of elapid snakes worldwide is the Australian genus Demansia, or whip snakes. Despite evidence to suggest adverse clinical outcomes from envenomation by these snakes, together with confusion on their true phylogenetic relationship to other Australian elapids, not a single toxin sequence has previously been reported from the venom of a Demansia species. We describe here a combined proteomic and transcriptomic approach characterizing the venom from the black whip snake, Demansia vestigiata. A total of 13 distinct toxin families were identified, including homologues of all of the major toxic components previously reported from the venom of other Australian elapids, such as factor X-like prothrombin activators, neurotoxins, phospholipases, cysteine rich secretory proteins, textilinin-like molecules, nerve growth factors, l-amino acid oxidases, vespryns, 5' nucleotidases, metalloproteinases, and C-type lectins as well as a novel dipeptidyl peptidase family. Phylogenetic analysis of these sequences revealed an early evolutionary split of the black whip snake from all other characterized Australian snakes, with a low degree of sequence identity between D. vestigiata and the other snakes, across all toxin families. The results of this study have important implications not only for the further characterization of venom from whip snakes, but also for our understanding of the evolutionary relationship of Australian snake species.

  4. Inositol hexakisphosphate-dependent processing of Clostridium sordellii lethal toxin and Clostridium novyi alpha-toxin.

    Science.gov (United States)

    Guttenberg, Gregor; Papatheodorou, Panagiotis; Genisyuerek, Selda; Lü, Wei; Jank, Thomas; Einsle, Oliver; Aktories, Klaus

    2011-04-29

    Clostridium sordellii lethal toxin and Clostridium novyi α-toxin, which are virulence factors involved in the toxic shock and gas gangrene syndromes, are members of the family of clostridial glucosylating toxins. The toxins inactivate Rho/Ras proteins by glucosylation or attachment of GlcNAc (α-toxin). Here, we studied the activation of the autoproteolytic processing of the toxins by inositol hexakisphosphate (InsP(6)) and compared it with the processing of Clostridium difficile toxin B. In the presence of low concentrations of InsP(6) (<1 μM), toxin fragments consisting of the N-terminal glucosyltransferase (or GlcNAc-transferase) domains and the cysteine protease domains (CPDs) of C. sordellii lethal toxin, C. novyi α-toxin, and C. difficile toxin B were autocatalytically processed. The cleavage sites of lethal toxin (Leu-543) and α-toxin (Leu-548) and the catalytic cysteine residues (Cys-698 of lethal toxin and Cys-707 of α-toxin) were identified. Affinity of the CPDs for binding InsP(6) was determined by isothermal titration calorimetry. In contrast to full-length toxin B and α-toxin, autocatalytic cleavage and InsP(6) binding of full-length lethal toxin depended on low pH (pH 5) conditions. The data indicate that C. sordellii lethal toxin and C. novyi α-toxin are InsP(6)-dependently processed. However, full-length lethal toxin, but not its short toxin fragments consisting of the glucosyltransferase domain and the CPD, requires a pH-sensitive conformational change to allow binding of InsP(6) and subsequent processing of the toxin.

  5. Inositol Hexakisphosphate-dependent Processing of Clostridium sordellii Lethal Toxin and Clostridium novyi α-Toxin*

    Science.gov (United States)

    Guttenberg, Gregor; Papatheodorou, Panagiotis; Genisyuerek, Selda; Lü, Wei; Jank, Thomas; Einsle, Oliver; Aktories, Klaus

    2011-01-01

    Clostridium sordellii lethal toxin and Clostridium novyi α-toxin, which are virulence factors involved in the toxic shock and gas gangrene syndromes, are members of the family of clostridial glucosylating toxins. The toxins inactivate Rho/Ras proteins by glucosylation or attachment of GlcNAc (α-toxin). Here, we studied the activation of the autoproteolytic processing of the toxins by inositol hexakisphosphate (InsP6) and compared it with the processing of Clostridium difficile toxin B. In the presence of low concentrations of InsP6 (<1 μm), toxin fragments consisting of the N-terminal glucosyltransferase (or GlcNAc-transferase) domains and the cysteine protease domains (CPDs) of C. sordellii lethal toxin, C. novyi α-toxin, and C. difficile toxin B were autocatalytically processed. The cleavage sites of lethal toxin (Leu-543) and α-toxin (Leu-548) and the catalytic cysteine residues (Cys-698 of lethal toxin and Cys-707 of α-toxin) were identified. Affinity of the CPDs for binding InsP6 was determined by isothermal titration calorimetry. In contrast to full-length toxin B and α-toxin, autocatalytic cleavage and InsP6 binding of full-length lethal toxin depended on low pH (pH 5) conditions. The data indicate that C. sordellii lethal toxin and C. novyi α-toxin are InsP6-dependently processed. However, full-length lethal toxin, but not its short toxin fragments consisting of the glucosyltransferase domain and the CPD, requires a pH-sensitive conformational change to allow binding of InsP6 and subsequent processing of the toxin. PMID:21385871

  6. Stool C difficile toxin

    Science.gov (United States)

    Antibiotic associated colitis - toxin; Colitis - toxin; Pseudomembranous - toxin; Necrotizing colitis - toxin; C difficile - toxin ... not recently taken antibiotics. This condition is called pseudomembranous colitis .

  7. Actions of snake neurotoxins on an insect nicotinic cholinergic synapse.

    Science.gov (United States)

    Hue, Bernard; Buckingham, Steven D; Buckingham, David; Sattelle, David B

    2007-09-01

    Here we examine the actions of six snake neurotoxins (alpha-cobratoxin from Naja naja siamensis, erabutoxin-a and b from Laticauda semifasciata; CM12 from N. haje annulifera, toxin III 4 from Notechis scutatus and a long toxin from N. haje) on nicotinic acetylcholine receptors in the cercal afferent, giant interneuron 2 synapse of the cockroach, Periplaneta americana. All toxins tested reduced responses to directly-applied ACh as well as EPSPs evoked by electrical stimulation of nerve XI with similar time courses, suggesting that their action is postsynaptic. Thus, these nicotinic receptors in a well-characterized insect synapse are sensitive to both long and short chain neurotoxins. This considerably expands the range of snake toxins that block insect nicotinic acetylcholine receptors and may enable further pharmacological distinctions between nAChR subtypes.

  8. Distinct Expression of Immunoglobulin-Binding Proteins in Shiga Toxin-Producing Escherichia coli Implicates High Protein Stability and a Characteristic Phenotype

    Science.gov (United States)

    Rubin, Dennis; Zhang, Wenlan; Karch, Helge; Kuczius, Thorsten

    2017-01-01

    Several immunoglobulin-binding proteins of Escherichia coli (Eib) have been isolated from both non-pathogenic and pathogenic E. coli strains. Shiga toxin (Stx)-producing E. coli (STEC) contain eibG either as a single gene or in combination with eibC, while other E. coli strains harbour single or multiple eib genes. The Eib proteins bind human immunoglobulins in a non-immune manner and contribute to bacterial chain-like adherence to human epithelial cells. In this study, the EibG expression in several STEC strains was analysed under different environmental conditions. STEC produced high levels of EibG in complex media and lower levels in low-grade and minimal media under static growth conditions. This characteristic was independent on the Eib subtypes. Microscopically, EibG-expressing STEC exhibited chain formation and aggregation in all employed media, while aggregates were only visible after growth in complex medium. Once expressed, EibG proteins demonstrate high stability during prolonged incubation. Our findings indicate that the regulation of the expression of Eib proteins is highly complex, although the protein levels vary among STEC strains. However, positive upregulation conditions generally result in distinct phenotypes of the isolates. PMID:28468281

  9. The interaction of the antitoxin DM43 with a snake venom metalloproteinase analyzed by mass spectrometry and surface plasmon resonance

    DEFF Research Database (Denmark)

    Brand, Guilherme D; Salbo, Rune; Jørgensen, Thomas J D

    2012-01-01

    DM43 is a circulating dimeric antitoxin isolated from Didelphis aurita, a South American marsupial naturally immune to snake envenomation. This endogenous inhibitor binds non-covalently to jararhagin, the main hemorrhagic metalloproteinase from Bothrops jararaca snake venom, and efficiently...

  10. Autoproteolytic Activation of Bacterial Toxins

    Directory of Open Access Journals (Sweden)

    Aimee Shen

    2010-05-01

    Full Text Available Protease domains within toxins typically act as the primary effector domain within target cells. By contrast, the primary function of the cysteine protease domain (CPD in Multifunctional Autoprocessing RTX-like (MARTX and Clostridium sp. glucosylating toxin families is to proteolytically cleave the toxin and release its cognate effector domains. The CPD becomes activated upon binding to the eukaryotic-specific small molecule, inositol hexakisphosphate (InsP6, which is found abundantly in the eukaryotic cytosol. This property allows the CPD to spatially and temporally regulate toxin activation, making it a prime candidate for developing anti-toxin therapeutics. In this review, we summarize recent findings related to defining the regulation of toxin function by the CPD and the development of inhibitors to prevent CPD-mediated activation of bacterial toxins.

  11. Fighting Cholera One-on-One: The Development and Efficacy of Multivalent Cholera-Toxin-Binding Molecules

    NARCIS (Netherlands)

    Zuilhof, H.

    2016-01-01

    A series of diseases, ranging from cholera via travelers’ diarrhea to hamburger disease, are caused by bacterially produced toxic proteins. In particular, a toxic protein unit is brought into the host cell upon binding to specific membrane-bound oligosaccharides on the host cell membrane. For

  12. Reproductive Disorders in Snakes.

    Science.gov (United States)

    Di Girolamo, Nicola; Selleri, Paolo

    2017-05-01

    Reproduction of snakes is one of the challenging aspects of herpetology medicine. Due to the complexity of reproduction, several disorders may present before, during, or after this process. This article describes the physical examination, and radiographic, ultrasonographic, and endoscopic findings associated with reproductive disorders in snakes. Surgical techniques used to resolve reproductive disorders in snakes are described. Finally, common reproductive disorders in snakes are individually discussed. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Snake venomics of Crotalus tigris: the minimalist toxin arsenal of the deadliest Nearctic rattlesnake venom. Evolutionary Clues for generating a pan-specific antivenom against crotalid type II venoms [corrected].

    Science.gov (United States)

    Calvete, Juan J; Pérez, Alicia; Lomonte, Bruno; Sánchez, Elda E; Sanz, Libia

    2012-02-03

    We report the proteomic and antivenomic characterization of Crotalus tigris venom. This venom exhibits the highest lethality for mice among rattlesnakes and the simplest toxin proteome reported to date. The venom proteome of C. tigris comprises 7-8 gene products from 6 toxin families; the presynaptic β-neurotoxic heterodimeric PLA(2), Mojave toxin, and two serine proteinases comprise, respectively, 66 and 27% of the C. tigris toxin arsenal, whereas a VEGF-like protein, a CRISP molecule, a medium-sized disintegrin, and 1-2 PIII-SVMPs each represent 0.1-5% of the total venom proteome. This toxin profile really explains the systemic neuro- and myotoxic effects observed in envenomated animals. In addition, we found that venom lethality of C. tigris and other North American rattlesnake type II venoms correlates with the concentration of Mojave toxin A-subunit, supporting the view that the neurotoxic venom phenotype of crotalid type II venoms may be described as a single-allele adaptation. Our data suggest that the evolutionary trend toward neurotoxicity, which has been also reported for the South American rattlesnakes, may have resulted by pedomorphism. The ability of an experimental antivenom to effectively immunodeplete proteins from the type II venoms of C. tigris, Crotalus horridus , Crotalus oreganus helleri, Crotalus scutulatus scutulatus, and Sistrurus catenatus catenatus indicated the feasibility of generating a pan-American anti-Crotalus type II antivenom, suggested by the identification of shared evolutionary trends among South and North American Crotalus species.

  14. Dangerous snakes, deadly snakes and medically important snakes.

    Science.gov (United States)

    Silva, Anjana

    2013-10-07

    This correspondence argues that the dangerousness of a venomous snake species is not solely determined by the venom characteristics or the lethality of the snake, and recognizes that medical importance comprises a key variable as well. The medical importance of a snake is determined by several factors - including frequency of medical attention after a bite, local or systemic envenomation provoked by the bite, fatal bites, long term consequences, availability of antivenom therapy as well as the size of the population at risk - that may vary from one region to another.

  15. A Review and Database of Snake Venom Proteomes

    Science.gov (United States)

    Tasoulis, Theo

    2017-01-01

    Advances in the last decade combining transcriptomics with established proteomics methods have made possible rapid identification and quantification of protein families in snake venoms. Although over 100 studies have been published, the value of this information is increased when it is collated, allowing rapid assimilation and evaluation of evolutionary trends, geographical variation, and possible medical implications. This review brings together all compositional studies of snake venom proteomes published in the last decade. Compositional studies were identified for 132 snake species: 42 from 360 (12%) Elapidae (elapids), 20 from 101 (20%) Viperinae (true vipers), 65 from 239 (27%) Crotalinae (pit vipers), and five species of non-front-fanged snakes. Approximately 90% of their total venom composition consisted of eight protein families for elapids, 11 protein families for viperines and ten protein families for crotalines. There were four dominant protein families: phospholipase A2s (the most common across all front-fanged snakes), metalloproteases, serine proteases and three-finger toxins. There were six secondary protein families: cysteine-rich secretory proteins, l-amino acid oxidases, kunitz peptides, C-type lectins/snaclecs, disintegrins and natriuretic peptides. Elapid venoms contained mostly three-finger toxins and phospholipase A2s and viper venoms metalloproteases, phospholipase A2s and serine proteases. Although 63 protein families were identified, more than half were present in snake species studied and always in low abundance. The importance of these minor component proteins remains unknown. PMID:28927001

  16. An Unusual Case of Acute Asthma after Snake Bite

    African Journals Online (AJOL)

    TNHJOURNALPH

    These presynaptically acting toxins exhibit phospholipase A;. activity. [7]. Cardiotoxins which cause augmentation of myocardial contractions at low concentration have been identified from cobra venoms [8]. Crotamine rattle snake venoms have a specific and unique effect on the sodium channel of excitable membrane [8].

  17. Targeted toxins in brain tumor therapy.

    Science.gov (United States)

    Li, Yan Michael; Hall, Walter A

    2010-11-01

    Targeted toxins, also known as immunotoxins or cytotoxins, are recombinant molecules that specifically bind to cell surface receptors that are overexpressed in cancer and the toxin component kills the cell. These recombinant proteins consist of a specific antibody or ligand coupled to a protein toxin. The targeted toxins bind to a surface antigen or receptor overexpressed in tumors, such as the epidermal growth factor receptor or interleukin-13 receptor. The toxin part of the molecule in all clinically used toxins is modified from bacterial or plant toxins, fused to an antibody or carrier ligand. Targeted toxins are very effective against cancer cells resistant to radiation and chemotherapy. They are far more potent than any known chemotherapy drug. Targeted toxins have shown an acceptable profile of toxicity and safety in early clinical studies and have demonstrated evidence of a tumor response. Currently, clinical trials with some targeted toxins are complete and the final results are pending. This review summarizes the characteristics of targeted toxins and the key findings of the important clinical studies with targeted toxins in malignant brain tumor patients. Obstacles to successful treatment of malignant brain tumors include poor penetration into tumor masses, the immune response to the toxin component and cancer heterogeneity. Strategies to overcome these limitations are being pursued in the current generation of targeted toxins.

  18. The Adenylate Cyclase Toxin of Bordetella pertussis Binds to Target Cells via the αMβ2 Integrin (Cd11b/Cd18)

    Science.gov (United States)

    Guermonprez, Pierre; Khelef, Nadia; Blouin, Eric; Rieu, Philippe; Ricciardi-Castagnoli, Paola; Guiso, Nicole; Ladant, Daniel; Leclerc, Claude

    2001-01-01

    The adenylate cyclase toxin (CyaA) of Bordetella pertussis is a major virulence factor required for the early phases of lung colonization. It can invade eukaryotic cells where, upon activation by endogenous calmodulin, it catalyzes the formation of unregulated cAMP levels. CyaA intoxication leads to evident toxic effects on macrophages and neutrophils. Here, we demonstrate that CyaA uses the αMβ2 integrin (CD11b/CD18) as a cell receptor. Indeed, the saturable binding of CyaA to the surface of various hematopoietic cell lines correlated with the presence of the αMβ2 integrin on these cells. Moreover, binding of CyaA to various murine cell lines and human neutrophils was specifically blocked by anti-CD11b monoclonal antibodies. The increase of intracellular cAMP level and cell death triggered by CyaA intoxication was also specifically blocked by anti-CD11b monoclonal antibodies. In addition, CyaA bound efficiently and triggered intracellular cAMP increase and cell death in Chinese hamster ovary cells transfected with αMβ2 (CD11b/CD18) but not in cells transfected with the vector alone or with the αXβ2 (CD11c/CD18) integrin. Thus, the cellular distribution of CD11b, mostly on neutrophils, macrophages, and dendritic and natural killer cells, supports a role for CyaA in disrupting the early, innate antibacterial immune response. PMID:11342588

  19. State of functionally essential Trp-29 in snake venom neurotoxins: a proton nuclear magnetic resonance study.

    Science.gov (United States)

    Endo, T; Oya, M; Joubert, F J; Hayashi, K; Miyazawa, T

    1989-08-01

    Proton nuclear magnetic resonance (NMR) spectra have been recorded of various neurotoxins from snake venoms. pH dependence of the chemical shifts and resonance intensity has been followed for the functionally essential Trp-29. The indole N-1 proton of Trp-29 in alpha-bungarotoxin, toxin B, and cobrotoxin exhibits appreciably large upfield shifts as the pH is lowered and the suppressed exchange with the solvent hydrogen at pH 3-4, but not in Naja haje annulifera 10 where Asp-31 is replaced with Gly-31. This observation strongly suggests the presence of a hydrogen bond between Trp-29 and Asp-31 that is probably important in stabilizing the arrangement of the functionally essential residues to form a distinct binding region for the receptor.

  20. Snake Venom Cytotoxins, Phospholipase A2s, and Zn2+-dependent Metalloproteinases: Mechanisms of Action and Pharmacological Relevance

    Science.gov (United States)

    Gasanov, Sardar E; Dagda, Ruben K; Rael, Eppie D

    2014-01-01

    Snake venom toxins are responsible for causing severe pathology and toxicity following envenomation including necrosis, apoptosis, neurotoxicity, myotoxicity, cardiotoxicity, profuse hemorrhage, and disruption of blood homeostasis. Clinically, snake venom toxins therefore represent a significant hazard to snakebite victims which underscores the need to produce more efficient anti-venom. Some snake venom toxins, however, have great potential as drugs for treating human diseases. In this review, we discuss the biochemistry, structure/function, and pathology induced by snake venom toxins on human tissue. We provide a broad overview of cobra venom cytotoxins, catalytically active and inactive phospholipase A2s (PLA2s), and Zn2+-dependent metalloproteinases. We also propose biomedical applications whereby snake venom toxins can be employed for treating human diseases. Cobra venom cytotoxins, for example, may be utilized as anti-cancer agents since they are efficient at destroying certain types of cancer cells including leukemia. Additionally, increasing our understanding of the molecular mechanism(s) by which snake venom PLA2s promote hydrolysis of cell membrane phospholipids can give insight into the underlying biomedical implications for treating autoimmune disorders that are caused by dysregulated endogenous PLA2 activity. Lastly, we provide an exhaustive overview of snake venom Zn2+-dependent metalloproteinases and suggest ways by which these enzymes can be engineered for treating deep vein thrombosis and neurodegenerative disorders. PMID:24949227

  1. Snake Venom Cytotoxins, Phospholipase A2s, and Zn(2+)-dependent Metalloproteinases: Mechanisms of Action and Pharmacological Relevance.

    Science.gov (United States)

    Gasanov, Sardar E; Dagda, Ruben K; Rael, Eppie D

    2014-01-25

    Snake venom toxins are responsible for causing severe pathology and toxicity following envenomation including necrosis, apoptosis, neurotoxicity, myotoxicity, cardiotoxicity, profuse hemorrhage, and disruption of blood homeostasis. Clinically, snake venom toxins therefore represent a significant hazard to snakebite victims which underscores the need to produce more efficient anti-venom. Some snake venom toxins, however, have great potential as drugs for treating human diseases. In this review, we discuss the biochemistry, structure/function, and pathology induced by snake venom toxins on human tissue. We provide a broad overview of cobra venom cytotoxins, catalytically active and inactive phospholipase A2s (PLA2s), and Zn(2+)-dependent metalloproteinases. We also propose biomedical applications whereby snake venom toxins can be employed for treating human diseases. Cobra venom cytotoxins, for example, may be utilized as anti-cancer agents since they are efficient at destroying certain types of cancer cells including leukemia. Additionally, increasing our understanding of the molecular mechanism(s) by which snake venom PLA2s promote hydrolysis of cell membrane phospholipids can give insight into the underlying biomedical implications for treating autoimmune disorders that are caused by dysregulated endogenous PLA2 activity. Lastly, we provide an exhaustive overview of snake venom Zn(2+)-dependent metalloproteinases and suggest ways by which these enzymes can be engineered for treating deep vein thrombosis and neurodegenerative disorders.

  2. Neuronal sensitivity to tetanus toxin requires gangliosides.

    Science.gov (United States)

    Williamson, L C; Bateman, K E; Clifford, J C; Neale, E A

    1999-08-27

    Tetanus toxin produces spastic paralysis in situ by blocking inhibitory neurotransmitter release in the spinal cord. Although di- and trisialogangliosides bind tetanus toxin, their role as productive toxin receptors remains unclear. We examined toxin binding and action in spinal cord cell cultures grown in the presence of fumonisin B(1), an inhibitor of ganglioside synthesis. Mouse spinal cord neurons grown for 3 weeks in culture in 20 microM fumonisin B(1) develop dendrites, axons, and synaptic terminals similar to untreated neurons, even though thin layer chromatography shows a greater than 90% inhibition of ganglioside synthesis. Absence of tetanus and cholera toxin binding by toxin-horseradish peroxidase conjugates or immunofluorescence further indicates loss of mono- and polysialogangliosides. In contrast to control cultures, tetanus toxin added to fumonisin B(1)-treated cultures does not block potassium-stimulated glycine release, inhibit activity-dependent uptake of FM1-43, or abolish immunoreactivity for vesicle-associated membrane protein, the toxin substrate. Supplementing fumonisin B(1)-treated cultures with mixed brain gangliosides completely restores the ability of tetanus toxin to bind to the neuronal surface and to block neurotransmitter release. These data demonstrate that fumonisin B(1) protects against toxin-induced synaptic blockade and that gangliosides are a necessary component of the receptor mechanism for tetanus toxin.

  3. The crystal structure of the Rv0301-Rv0300 VapBC-3 toxin-antitoxin complex from M. tuberculosis reveals a Mg2+ ion in the active site and a putative RNA-binding site

    Energy Technology Data Exchange (ETDEWEB)

    Min, Andrew B; Miallau, Linda; Sawaya, Michael R; Habel, Jeff; Cascio, Duilio; Eisenberg, David [UCLA; (UCB)

    2013-01-10

    VapBC pairs account for 45 out of 88 identified toxin-antitoxin (TA) pairs in the Mycobacterium tuberculosis (Mtb) H37Rv genome. A working model suggests that under times of stress, antitoxin molecules are degraded, releasing the toxins to slow the metabolism of the cell, which in the case of VapC toxins is via their RNase activity. Otherwise the TA pairs remain bound to their promoters, autoinhibiting transcription. The crystal structure of Rv0301-Rv0300, an Mtb VapBC TA complex determined at 1.49 Å resolution, suggests a mechanism for these three functions: RNase activity, its inhibition by antitoxin, and its ability to bind promoter DNA. The Rv0301 toxin consists of a core of five parallel beta strands flanked by alpha helices. Three proximal aspartates coordinate a Mg2+ ion forming the putative RNase active site. The Rv0300 antitoxin monomer is extended in structure, consisting of an N-terminal beta strand followed by four helices. The last two helices wrap around the toxin and terminate near the putative RNase active site, but with different conformations. In one conformation, the C-terminal arginine interferes with Mg2+ ion coordination, suggesting a mechanism by which the antitoxin can inhibit toxin activity. At the N-terminus of the antitoxin, two pairs of Ribbon-Helix-Helix (RHH) motifs are related by crystallographic twofold symmetry. The resulting hetero-octameric complex is similar to the FitAB system, but the two RHH motifs are about 30 Å closer together in the Rv0301-Rv0300 complex, suggesting either a different span of the DNA recognition sequence or a conformational change.

  4. Snake oil and venoms for medical research

    Science.gov (United States)

    Wolpert, H. D.

    2011-04-01

    Some think that using derivatives of snake venom for medical purposes is the modern version of snake oil but they are seriously misjudging the research potentials of some of these toxins in medicines of the 2000's. Medical trials, using some of the compounds has proven their usefulness. Several venoms have shown the possibilities that could lead to anticoagulants, helpful in heart disease. The blood clotting protein from the taipan snake has been shown to rapidly stop excessive bleeding. The venom from the copperhead may hold an answer to breast cancer. The Malaysian pit viper shows promise in breaking blood clots. Cobra venom may hold keys to finding cures for Parkinson's disease and Alzheimer's. Rattlesnake proteins from certain species have produced blood pressure medicines. Besides snake venoms, venom from the South American dart frog, mollusks (i.e. Cone Shell Snail), lizards (i.e. Gila Monster & Komodo Dragon), some species of spiders and tarantulas, Cephalopods, mammals (i.e. Platypus & Shrews), fish (i.e. sting rays, stone fish, puffer fish, blue bottle fish & box jelly fish), intertidal marine animals (echinoderms)(i.e. Crown of Thorn Star Fish & Flower Urchin) and the Honeybee are being investigated for potential medical benefits.

  5. Cholera toxin B subunit-binding and ganglioside GM1 immuno-expression are not necessarily correlated in human salivary glands.

    Science.gov (United States)

    Kirkeby, Svend

    2014-11-01

    To determine and compare the presence and in situ localization of the glycosphingolipid ganglioside GM1 in human salivary glands using the biomarkers for GM1: cholera toxin and antibodies against GM1. Immunohistochemical analyses were performed on sections of adult human submandibular, parotid and palatinal glands using cholera toxin sub-unit B and two polyclonal antibodies against ganglioside GM1 as biomarkers. Immunofluorescence microscopy showed that the toxin and antibodies were co-localized in some acini but not in others. The cholera toxin mainly reacted with the cell membranes of the mucous acini in the submandibular gland, while incubation with the antibody against GM1 gave rise to a staining of the cytoplasm. The cytoplasm in some secretory acinar cells in the parotid gland was stained by the cholera toxin, whereas only small spots on the plasma membranes reacted with anti-GM1. The plasma membranes in the parotid excretory ducts appeared to react to anti-GM1, but not to cholera toxin. Cholera toxin induces the expression of ion channels and carriers in the small intestine and increases the production of secretory mucins. Although their mutual immunohistochemical localization may differ, both cholera toxin and ganglioside GM1 are present in the mucin-producing acini from salivary glands. This could point to a relationship between ganglioside expression and production of salivary mucins.

  6. Cholera toxin B subunit-binding and ganglioside GM1 immuno-expression are not necessarily correlated in human salivary glands

    DEFF Research Database (Denmark)

    Kirkeby, Svend

    2014-01-01

    OBJECTIVE: To determine and compare the presence and in situ localization of the glycosphingolipid ganglioside GM1 in human salivary glands using the biomarkers for GM1: cholera toxin and antibodies against GM1. MATERIALS AND METHODS: Immunohistochemical analyses were performed on sections of adult...... human submandibular, parotid and palatinal glands using cholera toxin sub-unit B and two polyclonal antibodies against ganglioside GM1 as biomarkers. RESULTS: Immunofluorescence microscopy showed that the toxin and antibodies were co-localized in some acini but not in others. The cholera toxin mainly...... reacted with the cell membranes of the mucous acini in the submandibular gland, while incubation with the antibody against GM1 gave rise to a staining of the cytoplasm. The cytoplasm in some secretory acinar cells in the parotid gland was stained by the cholera toxin, whereas only small spots...

  7. Tetra- versus Pentavalent Inhibitors of Cholera Toxin

    NARCIS (Netherlands)

    Fu, Ou; Pukin, Aliaksei V.; Quarles Van Ufford, Linda; Branson, Thomas R.; Thies-Weesie, Dominique M E; Turnbull, W. Bruce; Visser, Gerben M.; Pieters, Roland J.

    2015-01-01

    The five B-subunits (CTB5) of the Vibrio cholerae (cholera) toxin can bind to the intestinal cell surface so the entire AB5 toxin can enter the cell. Simultaneous binding can occur on more than one of the monosialotetrahexosylganglioside (GM1) units present on the cell surface.

  8. Cholera toxin B subunit induces local curvature on lipid bilayers

    DEFF Research Database (Denmark)

    Pezeshkian, Weria; Nåbo, Lina J.; Ipsen, John H.

    2017-01-01

    The B subunit of the bacterial cholera toxin (CTxB) is responsible for the toxin binding to the cell membrane and its intracellular trafficking. CTxB binds to the monosialotetrahexosyl ganglioside at the plasma membrane of the target cell and mediates toxin internalization by endocytosis. CTx...

  9. Pertussis toxin

    Energy Technology Data Exchange (ETDEWEB)

    Sekura, R.D.; Moss, J.; Vaughan, M.

    1985-01-01

    This book contains 13 selections. Some of the titles are: Genetic and Functional Studies of Pertussis Toxin Substrates; Effect of Pertussis Toxin on the Hormonal Responsiveness of Different Tissues; Extracellular Adenylate Cyclase of Bordetella pertussis; and GTP-Regulatory Proteins are Introcellular Messagers: A Model for Hormone Action.

  10. Polyamine toxins

    DEFF Research Database (Denmark)

    Strømgaard, Kristian; Jensen, Lars S; Vogensen, Stine B

    2005-01-01

    Polyamine toxins, isolated from spiders and wasps, have been used as pharmacological tools for the study of ionotropic receptors, but their use have so far been hampered by their lack of selectivity. In this mini-review, we describe how careful synthetic modification of native polyamine toxins have...

  11. Botulinum toxin.

    Science.gov (United States)

    The National Institutes of Health Consensus Development Conference on Clinical Use of Botulinum Toxin brought together neurologists, ophthalmologists, otolaryngologists, speech pathologists, and other health care professionals as well as the public to address: the mechanisms of action of botulinum toxin, the indications and contraindications for botulinum toxin treatment, the general principles of technique of injection and handling for its safe and effective use, and the short-term and long-term side effects and complications of therapy. Following 2 days of presentations by experts and discussion by the audience, a consensus panel weighed the evidence and prepared their consensus statement. Among their findings, the panel recommended that (1) botulinum toxin therapy is safe and effective for treating strabismus, blepharospasm, hemifacial spasm, adductor spasmodic dysphonia, jaw-closing oromandibular dystonia, and cervical dystonia; (2) botulinum toxin is not curative in chronic neurological disorders; (3) the safety of botulinum toxin therapy during pregnancy, breast feeding, and chronic use during childhood is unknown; (4) the long-term effects of chronic treatment with botulinum toxin remain unknown; and (5) botulinum toxin should be administered by committed interdisciplinary teams of physicians and related health care professionals with appropriate instrumentation. The full text of the consensus panel's statement follows.

  12. Homicidal Snake Bite in Children.

    Science.gov (United States)

    Paulis, Melad G; Faheem, Ayman L

    2016-03-01

    Snake bites are common in many regions of the world. Snake envenomation is relatively uncommon in Egypt; such unfortunate events usually attract much publicity. Snake bite is almost only accidental, occurring in urban areas and desert. Few cases were reported to commit suicide by snake. Homicidal snake poisoning is so rare. It was known in ancient world by executing capital punishment by throwing the victim into a pit full of snakes. Another way was to ask the victim to put his hand inside a small basket harboring a deadly snake. Killing a victim by direct snake bite is so rare. There was one reported case where an old couple was killed by snake bite. Here is the first reported case of killing three children by snake bite. It appeared that the diagnosis of such cases is so difficult and depended mainly on the circumstantial evidences. © 2015 American Academy of Forensic Sciences.

  13. An invasive species induces rapid adaptive change in a native predator: cane toads and black snakes in Australia.

    Science.gov (United States)

    Phillips, Ben L; Shine, Richard

    2006-06-22

    Rapid environmental change due to human activities has increased rates of extinction, but some species may be able to adapt rapidly enough to deal with such changes. Our studies of feeding behaviour and physiological resistance to toxins reveal surprisingly rapid adaptive responses in Australian black snakes (Pseudechis porphyriacus) following the invasion of a lethally toxic prey item, the cane toad (Bufo marinus). Snakes from toad-exposed localities showed increased resistance to toad toxin and a decreased preference for toads as prey. Separate laboratory experiments suggest that these changes are not attributable to learning (we were unable to teach naive snakes to avoid toxic prey) or to acquired resistance (repeated sub-lethal doses did not enhance resistance). These results strongly suggest that black snake behaviour and physiology have evolved in response to the presence of toads, and have done so rapidly. Toads were brought to Australia in 1935, so these evolved responses have occurred in fewer than 23 snake generations.

  14. Discovery Of Human Antibodies Against Spitting Cobra Toxins

    DEFF Research Database (Denmark)

    Bojsen-Møller, Laura; Lohse, Brian; Harrison, Robert

    spitting cobras are among the most medically important snakes in sub-Saharan regions due to the severity of the clinical outcomes caused by their cytotoxic venom, which is derived from cytotoxins of the 3FTx toxin family and PLA2. Here we report the results of our progress in identifying human antibodies...... targeting relevant toxins from the venom of the black necked spitting cobra (Naja nigricolis)....

  15. The venom-gland transcriptome of the eastern coral snake (Micrurus fulvius) reveals high venom complexity in the intragenomic evolution of venoms

    National Research Council Canada - National Science Library

    Margres, Mark J; Aronow, Karalyn; Loyacano, Jacob; Rokyta, Darin R

    2013-01-01

    Snake venom is shaped by the ecology and evolution of venomous species, and signals of positive selection in toxins have been consistently documented, reflecting the role of venoms as an ecologically critical phenotype...

  16. Snake evolution and prospecting of snake venom

    NARCIS (Netherlands)

    Vonk, Freek Jacobus

    2012-01-01

    in this thesis I have shown that snakes have undergone multiple changes in their genome and embryonic development that has provided them with the variation to which natural selection could act. This thesis provides evidence for the variable mechanisms of venom gene evolution, which presumably is

  17. Revisiting Notechis scutatus venom: on shotgun proteomics and neutralization by the "bivalent" Sea Snake Antivenom.

    Science.gov (United States)

    Tan, Choo Hock; Tan, Kae Yi; Tan, Nget Hong

    2016-07-20

    Recent advances in proteomics enable deep profiling of the compositional details of snake venoms for improved understanding on envenomation pathophysiology and immunological neutralization. In this study, the venom of Australian tiger snake (Notechis scutatus) was trypsin-digested in solution and subjected to nano-ESI-LCMS/MS. Applying a relative quantitative proteomic approach, the findings revealed a proteome comprising 42 toxin subtypes clustered into 12 protein families. Phospholipases A2 constitute the most abundant toxins (74.5% of total venom proteins) followed by Kunitz serine protease inhibitors (6.9%), snake venom serine proteases (5.9%), alpha-neurotoxins (5.6%) and several toxins of lower abundance. The proteome correlates with N. scutatus envenoming effects including pre-synaptic and post-synaptic neurotoxicity and consumptive coagulopathy. The venom is highly lethal in mice (intravenous median lethal dose=0.09μg/g). BioCSL Sea Snake Antivenom, raised against the venoms of beaked sea snake (Hydrophis schistosus) and N. scutatus (added for enhanced immunogenicity), neutralized the lethal effect of N. scutatus venom (potency=2.95mg/ml) much more effectively than the targeted H.schistosus venom (potency=0.48mg/ml). The combined venom immunogen may have improved the neutralization against phospholipases A2 which are abundant in both venoms, but not short-neurotoxins which are predominant only in H. schistosus venom. A shotgun proteomic approach adopted in this study revealed the compositional details of the venom of common tiger snake from Australia, Notechis scutatus. The proteomic findings provided additional information on the relative abundances of toxins and the detection of proteins of minor expression unreported previously. The potent lethal effect of the venom was neutralized by bioCSL Sea Snake Antivenom, an anticipated finding due to the fact that the Sea Snake Antivenom is actually bivalent in nature, being raised against a mix of venoms of the

  18. Discovery of a distinct superfamily of Kunitz-type toxin (KTT from tarantulas.

    Directory of Open Access Journals (Sweden)

    Chun-Hua Yuan

    Full Text Available BACKGROUND: Kuntiz-type toxins (KTTs have been found in the venom of animals such as snake, cone snail and sea anemone. The main ancestral function of Kunitz-type proteins was the inhibition of a diverse array of serine proteases, while toxic activities (such as ion-channel blocking were developed under a variety of Darwinian selection pressures. How new functions were grafted onto an old protein scaffold and what effect Darwinian selection pressures had on KTT evolution remains a puzzle. PRINCIPAL FINDINGS: Here we report the presence of a new superfamily of ktts in spiders (TARANTULAS: Ornithoctonus huwena and Ornithoctonus hainana, which share low sequence similarity to known KTTs and is clustered in a distinct clade in the phylogenetic tree of KTT evolution. The representative molecule of spider KTTs, HWTX-XI, purified from the venom of O. huwena, is a bi-functional protein which is a very potent trypsin inhibitor (about 30-fold more strong than BPTI as well as a weak Kv1.1 potassium channel blocker. Structural analysis of HWTX-XI in 3-D by NMR together with comparative function analysis of 18 expressed mutants of this toxin revealed two separate sites, corresponding to these two activities, located on the two ends of the cone-shape molecule of HWTX-XI. Comparison of non-synonymous/synonymous mutation ratios (omega for each site in spider and snake KTTs, as well as PBTI like body Kunitz proteins revealed high Darwinian selection pressure on the binding sites for Kv channels and serine proteases in snake, while only on the proteases in spider and none detected in body proteins, suggesting different rates and patterns of evolution among them. The results also revealed a series of key events in the history of spider KTT evolution, including the formation of a novel KTT family (named sub-Kuntiz-type toxins derived from the ancestral native KTTs with the loss of the second disulfide bridge accompanied by several dramatic sequence modifications

  19. 50 CFR 226.205 - Critical habitat for Snake River sockeye salmon, Snake River fall chinook salmon, and Snake River...

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 7 2010-10-01 2010-10-01 false Critical habitat for Snake River sockeye salmon, Snake River fall chinook salmon, and Snake River spring/summer chinook salmon. 226.205 Section... Snake River sockeye salmon, Snake River fall chinook salmon, and Snake River spring/summer chinook...

  20. Beta-cardiotoxin: a new three-finger toxin from Ophiophagus hannah (king cobra) venom with beta-blocker activity.

    Science.gov (United States)

    Rajagopalan, Nandhakishore; Pung, Yuh Fen; Zhu, Yi Zhun; Wong, Peter Tsun Hon; Kumar, Prakash P; Kini, R Manjunatha

    2007-11-01

    Snake venoms have provided a number of novel ligands with therapeutic potential. We have constructed a partial cDNA library from the mRNA of Ophiophagus hannah (king cobra) venom gland tissue and identified five new genes encoding proteins belonging to the three-finger toxin family of snake venom proteins. We have isolated and characterized one of these beta-sheet containing proteins with a mass of 7012.43 +/- 0.91 Da from the venom. The protein was nonlethal up to a dose of 10 mg/kg when injected intraperitoneally into Swiss albino mice. However, it induces labored breathing and death at a dose of 100 mg/kg. It does not show any hemolytic or anticoagulant activity. It caused a dose-dependent decrease of heart rate in vivo (anesthetized Sprague-Dawley rats) and also ex vivo (Langendorff isolated rat heart). This is in contrast to classical cardiotoxins from snake venom that increase the heart rate in animals. Radioligand displacement studies showed that this protein targets beta-adrenergic receptors with a binding affinity (Ki) of 5.3 and 2.3 microM toward beta1 and beta2 subtypes, respectively, to bring about its effect, and hence, it was named as beta-cardiotoxin. This is the first report of a natural exogenous beta-blocker.

  1. The Mongwande Snake Cult

    OpenAIRE

    Moen, Sveinung

    2005-01-01

    Moen's work is one in a succession of recent studies of African traditions of knowledge, facing today's process of modernisation. The Mongwande snake cult is an example of how such traditions have survived intense influence from the modern schools and Christian mission. In the problematic situation of today it seems that these traditions are going through a revitalisation. The snake cult of the Mongwande is not a vanishing tradition, everything indicates that it has preserved its vitality and...

  2. Screening for target toxins of the antiophidic protein DM64 through a gel-based interactomics approach.

    Science.gov (United States)

    Rocha, Surza L G; Neves-Ferreira, Ana G C; Trugilho, Monique R O; Angulo, Yamileth; Lomonte, Bruno; Valente, Richard H; Domont, Gilberto B; Perales, Jonas

    2017-01-16

    DM64 is a glycosylated protein with antivenom activity isolated from the serum of the opossum Didelphis aurita. It binds non-covalently to myotoxins I (Asp49) and II (Lys49) from Bothrops asper venom and inhibits their myotoxic effect. In this study, an affinity column with immobilized DM64 as bait was used to fish potential target toxins. All ten isolated myotoxins tested were able to effectively bind to the DM64 column. To better access the specificity of the inhibitor, crude venoms from Bothrops (8 species), Crotalus (2 species) and Naja naja atra were submitted to the affinity purification. Venom fractions bound and nonbound to the DM64 column were analyzed by two-dimensional gel electrophoresis and MALDI-TOF/TOF MS. Although venom fractions bound to the column were mainly composed of basic PLA2, a few spots corresponding to acidic PLA2 were also observed. Some unexpected protein spots were also identified: C-type lectins and CRISP may represent putative new targets for DM64, whereas the presence of serine peptidases in the venom bound fraction is likely a consequence of nonspecific binding to the column matrix. The present results contribute to better delineate the inhibitory potential of DM64, providing a framework for the development of more specific antivenom therapies. Local tissue damage induced by myotoxic PLA2 remains a serious consequence of snake envenomation, since it is only partially neutralized by traditional antivenom serotherapy. Myotoxin inhibition by highly specific molecules offers great promise in the treatment of snakebites, a health problem largely neglected by governments and pharmaceutical industries. Bioactive compounds such as DM64 can represent a valuable source of scaffolds for drug development in this area. The present study has systematically profiled the binding specificity of DM64 toward a variety of snake venom toxin classes and therefore can lead to a better understanding of the structure-function relationship of this important

  3. Retrograde transport of protein toxins through the Golgi apparatus

    DEFF Research Database (Denmark)

    Sandvig, Kirsten; Skotland, Tore; van Deurs, Bo

    2013-01-01

    A number of protein toxins from plants and bacteria take advantage of transport through the Golgi apparatus to gain entry into the cytosol where they exert their action. These toxins include the plant toxin ricin, the bacterial Shiga toxins, and cholera toxin. Such toxins bind to lipids or proteins...... at the cell surface, and they are endocytosed both by clathrin-dependent and clathrin-independent mechanisms. Sorting to the Golgi and retrograde transport to the endoplasmic reticulum (ER) are common to these toxins, but the exact mechanisms turn out to be toxin and cell-type dependent. In the ER......, the enzymatically active part is released and then transported into the cytosol, exploiting components of the ER-associated degradation system. In this review, we will discuss transport of different protein toxins, but we will focus on factors involved in entry and sorting of ricin and Shiga toxin into and through...

  4. BOTULINUM TOXIN

    Science.gov (United States)

    Nigam, P K; Nigam, Anjana

    2010-01-01

    Botulinum toxin, one of the most poisonous biological substances known, is a neurotoxin produced by the bacterium Clostridium botulinum. C. botulinum elaborates eight antigenically distinguishable exotoxins (A, B, C1, C2, D, E, F and G). All serotypes interfere with neural transmission by blocking the release of acetylcholine, the principal neurotransmitter at the neuromuscular junction, causing muscle paralysis. The weakness induced by injection with botulinum toxin A usually lasts about three months. Botulinum toxins now play a very significant role in the management of a wide variety of medical conditions, especially strabismus and focal dystonias, hemifacial spasm, and various spastic movement disorders, headaches, hypersalivation, hyperhidrosis, and some chronic conditions that respond only partially to medical treatment. The list of possible new indications is rapidly expanding. The cosmetological applications include correction of lines, creases and wrinkling all over the face, chin, neck, and chest to dermatological applications such as hyperhidrosis. Injections with botulinum toxin are generally well tolerated and side effects are few. A precise knowledge and understanding of the functional anatomy of the mimetic muscles is absolutely necessary to correctly use botulinum toxins in clinical practice. PMID:20418969

  5. Botulinum toxin

    Directory of Open Access Journals (Sweden)

    Nigam P

    2010-01-01

    Full Text Available Botulinum toxin, one of the most poisonous biological substances known, is a neurotoxin produced by the bacterium Clostridium botulinum. C. botulinum elaborates eight antigenically distinguishable exotoxins (A, B, C 1 , C 2 , D, E, F and G. All serotypes interfere with neural transmission by blocking the release of acetylcholine, the principal neurotransmitter at the neuromuscular junction, causing muscle paralysis. The weakness induced by injection with botulinum toxin A usually lasts about three months. Botulinum toxins now play a very significant role in the management of a wide variety of medical conditions, especially strabismus and focal dystonias, hemifacial spasm, and various spastic movement disorders, headaches, hypersalivation, hyperhidrosis, and some chronic conditions that respond only partially to medical treatment. The list of possible new indications is rapidly expanding. The cosmetological applications include correction of lines, creases and wrinkling all over the face, chin, neck, and chest to dermatological applications such as hyperhidrosis. Injections with botulinum toxin are generally well tolerated and side effects are few. A precise knowledge and understanding of the functional anatomy of the mimetic muscles is absolutely necessary to correctly use botulinum toxins in clinical practice.

  6. Compartment Syndrome Following Snake Bite

    National Research Council Canada - National Science Library

    Dhar, Dinesh

    2015-01-01

    .... The local effects of snake bite include tissue necrosis, edema, and compartment syndrome. Patients may also be left with permanent physical deformities due to residual sequelae of the snake bite...

  7. Strike Back Against Snake Bites

    Science.gov (United States)

    ... gov/news/fullstory_166748.html Strike Back Against Snake Bites Expert advice on what to do if ... News) -- With summer comes a higher risk of snake bites, but emergency doctors have some advice on ...

  8. Snake venomics and venom gland transcriptomic analysis of Brazilian coral snakes, Micrurus altirostris and M. corallinus.

    Science.gov (United States)

    Corrêa-Netto, Carlos; Junqueira-de-Azevedo, Inácio de L M; Silva, Débora A; Ho, Paulo L; Leitão-de-Araújo, Moema; Alves, Maria Lúcia M; Sanz, Libia; Foguel, Débora; Zingali, Russolina Benedeta; Calvete, Juan J

    2011-08-24

    The venom proteomes of Micrurus altirostris and M. corallinus were analyzed by combining snake venomics and venom gland transcriptomic surveys. In both coral snake species, 3FTx and PLA(2) were the most abundant and diversified toxin families. 33 different 3FTxs and 13 PLA(2) proteins, accounting respectively for 79.5% and 13.7% of the total proteins, were identified in the venom of M. altirostris. The venom of M. corallinus comprised 10 3FTx (81.7% of the venom proteome) and 4 (11.9%) PLA(2) molecules. Transcriptomic data provided the full-length amino acid sequences of 18 (M. altirostris) and 10 (M. corallinus) 3FTxs, and 3 (M. altirostris) and 1 (M. corallinus) novel PLA(2) sequences. In addition, venom from each species contained single members of minor toxin families: 3 common (PIII-SVMP, C-type lectin-like, L-amino acid oxidase) and 4 species-specific (CRISP, Kunitz-type inhibitor, lysosomal acid lipase in M. altirostris; serine proteinase in M. corallinus) toxin classes. The finding of a lipase (LIPA) in the venom proteome and in the venom gland transcriptome of M. altirostris supports the view of a recruitment event predating the divergence of Elapidae and Viperidae more than 60 Mya. The toxin profile of both M. altirostris and M. corallinus venoms points to 3FTxs and PLA(2) molecules as the major players of the envenoming process. In M. altirostris venom, all major, and most minor, 3FTxs display highest similarity to type I α-neurotoxins, suggesting that these postsynaptically acting toxins may play the predominant role in the neurotoxic effect leading to peripheral paralysis, respiratory arrest, and death. M. corallinus venom posesses both, type I α-neurotoxins and a high-abundance (26% of the venom proteome) protein of subfamily XIX of 3FTxs, exhibiting similarity to bucandin from Malayan krait, Bungarus candidus, venom, which enhances acetylcholine release presynaptically. This finding may explain the presynaptic neurotoxicity of M. corallinus venom

  9. Snakes: An Integrated Unit Plan.

    Science.gov (United States)

    Lawrence, Lisa

    This document presents an integrated unit plan on snakes targeting second grade students. Objectives of the unit include developing concepts of living things, understanding the contribution and importance of snakes to the environment, and making connections between different disciplines. The unit integrates the topic of snakes into the areas of…

  10. The king cobra genome reveals dynamic gene evolution and adaptation in the snake venom system.

    Science.gov (United States)

    Vonk, Freek J; Casewell, Nicholas R; Henkel, Christiaan V; Heimberg, Alysha M; Jansen, Hans J; McCleary, Ryan J R; Kerkkamp, Harald M E; Vos, Rutger A; Guerreiro, Isabel; Calvete, Juan J; Wüster, Wolfgang; Woods, Anthony E; Logan, Jessica M; Harrison, Robert A; Castoe, Todd A; de Koning, A P Jason; Pollock, David D; Yandell, Mark; Calderon, Diego; Renjifo, Camila; Currier, Rachel B; Salgado, David; Pla, Davinia; Sanz, Libia; Hyder, Asad S; Ribeiro, José M C; Arntzen, Jan W; van den Thillart, Guido E E J M; Boetzer, Marten; Pirovano, Walter; Dirks, Ron P; Spaink, Herman P; Duboule, Denis; McGlinn, Edwina; Kini, R Manjunatha; Richardson, Michael K

    2013-12-17

    Snakes are limbless predators, and many species use venom to help overpower relatively large, agile prey. Snake venoms are complex protein mixtures encoded by several multilocus gene families that function synergistically to cause incapacitation. To examine venom evolution, we sequenced and interrogated the genome of a venomous snake, the king cobra (Ophiophagus hannah), and compared it, together with our unique transcriptome, microRNA, and proteome datasets from this species, with data from other vertebrates. In contrast to the platypus, the only other venomous vertebrate with a sequenced genome, we find that snake toxin genes evolve through several distinct co-option mechanisms and exhibit surprisingly variable levels of gene duplication and directional selection that correlate with their functional importance in prey capture. The enigmatic accessory venom gland shows a very different pattern of toxin gene expression from the main venom gland and seems to have recruited toxin-like lectin genes repeatedly for new nontoxic functions. In addition, tissue-specific microRNA analyses suggested the co-option of core genetic regulatory components of the venom secretory system from a pancreatic origin. Although the king cobra is limbless, we recovered coding sequences for all Hox genes involved in amniote limb development, with the exception of Hoxd12. Our results provide a unique view of the origin and evolution of snake venom and reveal multiple genome-level adaptive responses to natural selection in this complex biological weapon system. More generally, they provide insight into mechanisms of protein evolution under strong selection.

  11. North American Snake Envenomation.

    Science.gov (United States)

    Corbett, Bryan; Clark, Richard F

    2017-05-01

    Native US snakes that produce clinically significant envenomation can be divided into 2 groups, crotalids and elapids. The crotalids include rattlesnakes, cottonmouths, and copperheads. Crotalid envenomation can result in significant local tissue damage as well as thrombocytopenia and coagulopathy. Rarely are bites fatal. Native US elapids are all coral snakes that possess neurotoxic venom that can cause weakness, respiratory paralysis, and rarely death. Treatment of both types of envenomation revolves around general supportive care and antivenom administration when indicated. Previously advocated treatments, such as tourniquets, venom extraction, and bite site excision are not recommended. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. Pulmonoscopy of Snakes.

    Science.gov (United States)

    Knotek, Zdenek; Jekl, Vladimir

    2015-09-01

    Pulmonoscopy is a practical diagnostic tool for investigating respiratory diseases in snakes. Two different approaches exist for pulmonoscopy, tracheal and transcutaneous. The access to the proximal or distal lung is limited by the length and diameter of the endoscope when using the tracheal approach. The transcutaneous approach allows direct evaluation of the lung and distal trachea through the air sac. Both of the methods are safe, and specific contraindications for pulmonoscopy in snakes are not known except for any anesthesia contraindication. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. A heterodimer of a VHH (variable domains of camelid heavy chain-only) antibody that inhibits anthrax toxin cell binding linked to a VHH antibody that blocks oligomer formation is highly protective in an anthrax spore challenge model.

    Science.gov (United States)

    Moayeri, Mahtab; Leysath, Clinton E; Tremblay, Jacqueline M; Vrentas, Catherine; Crown, Devorah; Leppla, Stephen H; Shoemaker, Charles B

    2015-03-06

    Anthrax disease is caused by a toxin consisting of protective antigen (PA), lethal factor, and edema factor. Antibodies against PA have been shown to be protective against the disease. Variable domains of camelid heavy chain-only antibodies (VHHs) with affinity for PA were obtained from immunized alpacas and screened for anthrax neutralizing activity in macrophage toxicity assays. Two classes of neutralizing VHHs were identified recognizing distinct, non-overlapping epitopes. One class recognizes domain 4 of PA at a well characterized neutralizing site through which PA binds to its cellular receptor. A second neutralizing VHH (JKH-C7) recognizes a novel epitope. This antibody inhibits conversion of the PA oligomer from "pre-pore" to its SDS and heat-resistant "pore" conformation while not preventing cleavage of full-length 83-kDa PA (PA83) by cell surface proteases to its oligomer-competent 63-kDa form (PA63). The antibody prevents endocytosis of the cell surface-generated PA63 subunit but not preformed PA63 oligomers formed in solution. JKH-C7 and the receptor-blocking VHH class (JIK-B8) were expressed as a heterodimeric VHH-based neutralizing agent (VNA2-PA). This VNA displayed improved neutralizing potency in cell assays and protected mice from anthrax toxin challenge with much better efficacy than the separate component VHHs. The VNA protected virtually all mice when separately administered at a 1:1 ratio to toxin and protected mice against Bacillus anthracis spore infection. Thus, our studies show the potential of VNAs as anthrax therapeutics. Due to their simple and stable nature, VNAs should be amenable to genetic delivery or administration via respiratory routes. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  14. Snake venom metalloproteinases.

    Science.gov (United States)

    Markland, Francis S; Swenson, Stephen

    2013-02-01

    Recent proteomic analyses of snake venoms show that metalloproteinases represent major components in most of the Crotalid and Viperid venoms. In this chapter we discuss the multiple activities of the SVMPs. In addition to hemorrhagic activity, members of the SVMP family also have fibrin(ogen)olytic activity, act as prothrombin activators, activate blood coagulation factor X, possess apoptotic activity, inhibit platelet aggregation, are pro-inflammatory and inactivate blood serine proteinase inhibitors. Clearly the SVMPs have multiple functions in addition to their well-known hemorrhagic activity. The realization that there are structural variations in the SVMPs and the early studies that led to their classification represents an important event in our understanding of the structural forms of the SVMPs. The SVMPs were subdivided into the P-I, P-II and P-III protein classes. The noticeable characteristic that distinguished the different classes was their size (molecular weight) differences and domain structure: Class I (P-I), the small SVMPs, have molecular masses of 20-30 kDa, contain only a pro domain and the proteinase domain; Class II (P-II), the medium size SVMPs, molecular masses of 30-60 kDa, contain the pro domain, proteinase domain and disintegrin domain; Class III (P-III), the large SVMPs, have molecular masses of 60-100 kDa, contain pro, proteinase, disintegrin-like and cysteine-rich domain structure. Another significant advance in the SVMP field was the characterization of the crystal structure of the first P-I class SVMP. The structures of other P-I SVMPs soon followed and the structures of P-III SVMPs have also been determined. The active site of the metalloproteinase domain has a consensus HEXXHXXGXXHD sequence and a Met-turn. The "Met-turn" structure contains a conserved Met residue that forms a hydrophobic basement for the three zinc-binding histidines in the consensus sequence. Copyright © 2012 Elsevier Ltd. All rights reserved.

  15. Toxicovenomics and antivenom profiling of the Eastern green mamba snake (Dendroaspis angusticeps)

    DEFF Research Database (Denmark)

    Lauridsen, Line P.; Laustsen, Andreas Hougaard; Lomonte, Bruno

    2016-01-01

    and immunoprecipitated the crude venom by gel immunodiffusion. The synergistic mechanism of toxicity constitutes a challenge for the development of effective recombinant antibodies, as it requires the identification of the most relevant synergistic toxins. Biological significance: Envenomings by elapid snakes...

  16. Bothrops jararaca venom gland secretory cells in culture: Effects of noradrenaline on toxin production and secretion.

    Science.gov (United States)

    Viana, Luciana Godoy; Valente, Richard Hemmi; Heluany, Cíntia Scucuglia; Souza-Imberg, Andreia; Luna, Milene Schmidt; Perales, Jonas; Yamanouye, Norma

    2017-07-01

    Primary culture of snake venom gland secretory cells could be a good model to study the mechanism(s) of toxin(s) production. These cells can produce and secrete venom to the medium with a hemorrhagic activity comparable to that induced by venom collected from snakes. Production of new venom is triggered by the sympathetic outflow, through the release of noradrenaline, but the importance of this neurotransmitter on toxin synthesis has not been addressed. This work led to the identification and comparison of the toxin panel produced by cultured secretory cells, during a 12-day time-course analysis, as well as to the effects of noradrenaline on the process. The results showed that in our culture model the synthesis of new toxins is asynchronous, mimicking data previously published from proteomic analyses of venom glands harvested from animal experimentation. Furthermore, noradrenaline did regulate the synthesis and/or secretion of venom toxins over the analyzed period. Finally, we demonstrated that snake venom metalloproteinases present in these cultured cells secretome were mostly in their zymogen forms; consequently, processing occurs after secretion to the gland lumen. Overall, the data support the use of venom gland secretory cells as a reliable model to investigate the mechanism(s) of toxin(s) synthesis and secretion. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. The in vitro neuromuscular activity of Indo-Pacific sea-snake venoms: efficacy of two commercially available antivenoms.

    Science.gov (United States)

    Chetty, Navinisha; Du, Amanda; Hodgson, Wayne C; Winkel, Ken; Fry, Bryan G

    2004-08-01

    We examined the neurotoxicity of the following sea snake venoms: Enhydrina schistosa (geographical variants from Weipa and Malaysia), Lapemis curtus (Weipa and Malaysia), Laticauda colubrina, Aipysurus laevis, Aipysurus fuscus and Aipysurus foliosquamatus. Venom from a terrestrial snake, Notechis scutatus (tiger snake), was used as a reference. All venoms (1 and 3 microg/ml) abolished indirect twitches of the chick biventer cervicis muscle and significantly inhibited responses to ACh (1 mM) and CCh (20 microM), but not KCl (40 mM), indicating the presence of post-synaptic toxins. Prior administration (10 min) of CSL sea snake antivenom (1 unit/ml) attenuated the twitch blockade produced by N. scutatus venom and all sea snake venoms (1 microg/ml). Prior administration (10 min) of CSL tiger snake antivenom (1 unit/ml) attenuated the twitch blockade of all venoms except those produced by E. schistosa (Malaysia and Weipa) and A. foliosquamatus. Administration of CSL sea snake antivenom (1 unit/ml) at t90 (i.e. time at which 90% inhibition of initial twitch height occurred) reversed the inhibition of twitches (20-50%) produced by the sea snake venoms (1 microg/ml) but not by N. scutatus venom (1 microg/ml). CSL tiger snake antivenom (1 unit/ml) administered at t90 produced only minor reversal (i.e. 15-25%) of the twitch blockade caused by L. curtus (Weipa), A. foliosquamatus, L. colubrina and A. laevis venoms (1 microg/ml). Differences in the rate of reversal of the neurotoxicity produced by the two geographical variants of E. schistosa venom, after addition of CSL sea snake antivenom, indicate possible differences in venom components. This study shows that sea snake venoms contain potent post-synaptic activity that, despite the significant genetic distances between the lineages, can be neutralised with CSL sea snake antivenom. However, the effects of CSL tiger snake antivenom are more variable.

  18. Identification of the cellular receptor of Clostridium spiroforme toxin.

    Science.gov (United States)

    Papatheodorou, Panagiotis; Wilczek, Claudia; Nölke, Thilo; Guttenberg, Gregor; Hornuss, Daniel; Schwan, Carsten; Aktories, Klaus

    2012-04-01

    Clostridium spiroforme produces the binary actin-ADP-ribosylating toxin CST (C. spiroforme toxin), which has been proposed to be responsible for diarrhea, enterocolitis, and eventually death, especially in rabbits. Here we report on the recombinant production of the enzyme component (CSTa) and the binding component (CSTb) of C. spiroforme toxin in Bacillus megaterium. By using the recombinant toxin components, we show that CST enters target cells via the lipolysis-stimulated lipoprotein receptor (LSR), which has been recently identified as the host cell receptor of the binary toxins Clostridium difficile transferase (CDT) and Clostridium perfringens iota toxin. Microscopic studies revealed that CST, but not the related Clostridium botulinum C2 toxin, colocalized with LSR during toxin uptake and traffic to endosomal compartments. Our findings indicate that CST shares LSR with C. difficile CDT and C. perfringens iota toxin as a host cell surface receptor.

  19. Blocking the QB-binding site of photosystem II by tenuazonic acid, a non-host-specific toxin of Alternaria alternata, activates singlet oxygen-mediated and EXECUTER-dependent signalling in Arabidopsis.

    Science.gov (United States)

    Chen, Shiguo; Kim, Chanhong; Lee, Je Min; Lee, Hyun-Ah; Fei, Zhangjun; Wang, Liangsheng; Apel, Klaus

    2015-06-01

    Necrotrophic fungal pathogens produce toxic compounds that induce cell death in infected plants. Often, the primary targets of these toxins and the way a plant responds to them are not known. In the present work, the effect of tenuazonic acid (TeA), a non-host-specific toxin of Alternaria alternata, on Arabidopsis thaliana has been analysed. TeA blocks the QB -binding site at the acceptor side of photosystem II (PSII). As a result, charge recombination at the reaction centre (RC) of PSII is expected to enhance the formation of the excited triplet state of the RC chlorophyll that promotes generation of singlet oxygen ((1)O₂). (1)O₂ activates a signalling pathway that depends on the two EXECUTER (EX) proteins EX1 and EX2 and triggers a programmed cell death response. In seedlings treated with TeA at half-inhibition concentration (1)O₂-mediated and EX-dependent signalling is activated as indicated by the rapid and transient up-regulation of (1)O₂-responsive genes in wild type, and its suppression in ex1/ex2 mutants. Lesion formation occurs when seedlings are exposed to higher concentrations of TeA for a longer period of time. Under these conditions, the programmed cell death response triggered by (1)O₂-mediated and EX-dependent signalling is superimposed by other events that also contribute to lesion formation. © 2014 John Wiley & Sons Ltd.

  20. Molecular basis for tetanus toxin coreceptor interactions.

    Science.gov (United States)

    Chen, Chen; Baldwin, Michael R; Barbieri, Joseph T

    2008-07-08

    Tetanus toxin (TeNT) elicits spastic paralysis through the cleavage of vesicle-associated membrane protein-2 (VAMP-2) in neurons at the interneuronal junction of the central nervous system. While TeNT retrograde traffics from peripheral nerve endings to the interneuronal junction, there is limited understanding of the neuronal receptors utilized by tetanus toxin for the initial entry into nerve cells. Earlier studies implicated a coreceptor for tetanus toxin entry into neurons: a ganglioside binding pocket and a sialic acid binding pocket and that GT1b bound to each pocket. In this study, a solid phase assay characterized the ganglioside binding specificity and functional properties of both carbohydrate binding pockets of TeNT. The ganglioside binding pocket recognized the ganglioside sugar backbone, Gal-GalNAc, independent of sialic acid-(5) and sialic acid-(7) and GM1a was an optimal substrate for this pocket, while the sialic acid binding pocket recognized sialic acid-(5) and sialic acid-(7) with "b"series of gangliosides preferred relative to "a" series gangliosides. The high-affinity binding of gangliosides to TeNT HCR required functional ganglioside and sialic acid binding pockets, supporting synergistic binding to coreceptors. This analysis provides a model for how tetanus toxin utilizes coreceptors for high-affinity binding to neurons.

  1. [Phalloidian toxins].

    Science.gov (United States)

    Larcan, A; Lamarche, M; Lambert, H

    1979-01-01

    The phalloidian toxins are very complex. The classification proposed by Wieland distinguishes between the various amatoxins and phallotoxins. The authors study successively: Methods of isolation, the general structure and chemical composition, their localization and concentration in mushrooms. This is an analytical study of the phallotoxins and amadoxins. Various experimental intoxication protocols using total extracts of the toxins purified with different doses and different animals have revealed the main signs of experimental intoxication with phallotoxins. This is characterized especially by hepatic and renal lesions. The phallotoxins have a more specific action on the cell membrane and metabolism. The amatoxins have a more specific action on the cell nucleus and protein synthesis. The action on DNA dependent RNA polymerases is particularly characteristic.

  2. Snow snake performance monitoring.

    Science.gov (United States)

    2008-12-01

    A recent study, Three-Dimensional Roughness Elements for Snow Retention (FHWA-WY-06/04F) (Tabler 2006), demonstrated : positive evidence for the effectiveness of Snow Snakes, a new type of snow fence suitable for use within the highway right-of...

  3. Where Galactic Snakes Live

    Science.gov (United States)

    2006-01-01

    This infrared image from NASA's Spitzer Space Telescope shows what astronomers are referring to as a 'snake' (upper left) and its surrounding stormy environment. The sinuous object is actually the core of a thick, sooty cloud large enough to swallow dozens of solar systems. In fact, astronomers say the 'snake's belly' may be harboring beastly stars in the process of forming. The galactic creepy crawler to the right of the snake is another thick cloud core, in which additional burgeoning massive stars might be lurking. The colorful regions below the two cloud cores are less dense cloud material, in which dust has been heated by starlight and glows with infrared light. Yellow and orange dots throughout the image are monstrous developing stars; the red star on the 'belly' of the snake is 20 to 50 times as massive as our sun. The blue dots are foreground stars. The red ball at the bottom left is a 'supernova remnant,' the remains of massive star that died in a fiery blast. Astronomers speculate that radiation and winds from the star before it died, in addition to a shock wave created when it exploded, might have played a role in creating the snake. Spitzer was able to spot the two black cloud cores using its heat-seeking infrared vision. The objects are hiding in the dusty plane of our Milky Way galaxy, invisible to optical telescopes. Because their heat, or infrared light, can sneak through the dust, they first showed up in infrared images from past missions. The cloud cores are so thick with dust that if you were to somehow transport yourself into the middle of them, you would see nothing but black, not even a star in the sky. Now, that's spooky! Spitzer's new view of the region provides the best look yet at the massive embryonic stars hiding inside the snake. Astronomers say these observations will ultimately help them better understand how massive stars form. By studying the clustering and range of masses of the stellar embryos, they hope to determine if the stars

  4. Guanosine 5'-triphosphate binding protein (G/sub i/) and two additional pertussis toxin substrates associated with muscarinic receptors in rat heart myocytes: characterization and age dependency

    Energy Technology Data Exchange (ETDEWEB)

    Moscona-Amir, E.; Henis, Y.I.; Sokolovsky, M.

    1988-07-12

    The coupling of muscarinic receptors with G-proteins was investigated in cultured myocytes prepared from the hearts of newborn rats. The coupling was investigated in both young (5 days after plating) and aged (14 days after plating) cultures, in view of the completely different effects of 5'-guanylyl imidodiphosphate (Gpp(NH)p) on muscarinic agonist binding to homogenates from young vs aged cultures. Pretreatment of cultures from both ages by Bordetella pertussis toxin (IAP) was found to eliminate any Gpp(NH)p effect on carbamylcholine binding. IAP by itself induced a rightward shift in the carbamylcholine competition curve in homogenates from aged cultures, but no such effect was observed in homogenates from young cultures. IAP-catalyzed (/sup 32/P)ADP-ribosylation of membrane preparations from young and aged cultures revealed major differences between them. Young cultures exhibited a major IAP substrate at 40 kDa, which was also recognized by anti-..cap alpha../sub i/ antibodies, and two novel IAP substrates at 28 and 42 kDa, which were weakly ADP-ribosylated by the toxin and were not recognized with either anti-..cap alpha../sub i/ or anti-..cap alpha../sub 0/ antibodies. In aged cultures, only the 40-kDa band (ribosylated to a lower degree) was detected. The parallel age-dependent changes in the three IAP substrates (28, 40, and 42 kDa) and in the interactions of the G-protein(s) with the muscarinic receptors strongly suggest close association between the two phenomena. All of these age-dependent changes in the G-protein related parameters were prevented by phosphatidylcholine-liposome treatment of the aged cultures. The role of the membrane lipid composition in these phenomena is discussed.

  5. Crystal structure of a snake venom cardiotoxin

    Energy Technology Data Exchange (ETDEWEB)

    Rees, B.; Samama, J.P.; Thierry, J.C.; Gilibert, M.; Fischer, J.; Schweitz, H.; Lazdunski, M.; Moras, D.

    1987-05-01

    Cardiotoxin V/sup II/4 from Naja mossambica crystallizes in space group P6/sub 1/ (a = b = 73.9 A; c = 59.0 A) with two molecules of toxin (molecular mass = 6715 Da) in the asymmetric unit. The structure was solved by using a combination of multiple isomorphous replacement and density modification methods. Model building and least-squares refinement led to an agreement factor of 27% for a data set to 3-A resolution prior to any inclusion of solvent molecules. The topology of the molecule is similar to that found in short and long snake neurotoxins, which block the nicotinic acetylcholine receptor. Major differences occur in the conformation of the central loop, resulting in a change in the concavity of the molecule. Hydrophobic residues are clustered in two distinct areas. The existence of stable dimeric entities in the crystalline state, with the formation of a six-stranded antiparallel ..beta.. sheet, may be functionally relevant.

  6. [Understanding snake venoms: 50 years of research in Latin America].

    Science.gov (United States)

    Gutiérrez, José María

    2002-06-01

    As a tribute to Revista de Biología Tropical in its 50th anniversary, this review describes some of the main research efforts carried out in the study of the chemical composition and the mechanism of action of toxins present in the venoms of snakes distributed in Latin America. Venom proteins involved in neurotoxicity, coagulopathies, hemorrhage and muscle necrosis are discussed, together with a description of the inflammatory reactions elicited by these venoms and toxins. In addition, the search for inhibitory substances present in plants and animals that may be utilized in the neutralization of venoms is analyzed. Some of the clinical studies performed on snakebite envenomations in Latin America are also reviewed, together with the development of technologies aimed at improving the quality of antivenoms produced in the region. Toxinology has become a fruitful and stimulating research field in Latin America which has contributed to a better understanding of snake venoms as well as to an improved management of snake bitten patients.

  7. Endothelial binding of beta toxin to small intestinal mucosal endothelial cells in early stages of experimentally induced Clostridium perfringens type C enteritis in pigs.

    Science.gov (United States)

    Schumacher, V L; Martel, A; Pasmans, F; Van Immerseel, F; Posthaus, H

    2013-07-01

    Beta toxin (CPB) is known to be an essential virulence factor in the development of lesions of Clostridium perfringens type C enteritis in different animal species. Its target cells and exact mechanism of toxicity have not yet been clearly defined. Here, we evaluate the suitability of a neonatal piglet jejunal loop model to investigate early lesions of C. perfringens type C enteritis. Immunohistochemically, CPB was detected at microvascular endothelial cells in intestinal villi during early and advanced stages of lesions induced by C. perfringens type C. This was first associated with capillary dilatation and subsequently with widespread hemorrhage in affected intestinal segments. CPB was, however, not demonstrated on intestinal epithelial cells. This indicates a tropism of CPB toward endothelial cells and suggests that CPB-induced endothelial damage plays an important role in the early stages of C. perfringens type C enteritis in pigs.

  8. Neutralization of the Principal Toxins from the Venoms of Thai Naja kaouthia and Malaysian Hydrophis schistosus: Insights into Toxin-Specific Neutralization by Two Different Antivenoms

    OpenAIRE

    Kae Yi Tan; Choo Hock Tan; Shin Yee Fung; Nget Hong Tan

    2016-01-01

    Antivenom neutralization against cobra venoms is generally low in potency, presumably due to poor toxin-specific immunoreactivity. This study aimed to investigate the effectiveness of two elapid antivenoms to neutralize the principal toxins purified from the venoms of the Thai monocled cobra (Naja kaouthia, Nk-T) and the Malaysian beaked sea snake (Hydrophis schistosus, Hs-M). In mice, N. kaouthia Monovalent Antivenom (NKMAV) neutralization against Nk-T long neurotoxin (LNTX) and cytotoxin wa...

  9. Anthrax toxin receptor 2-dependent lethal toxin killing in vivo.

    Directory of Open Access Journals (Sweden)

    Heather M Scobie

    2006-10-01

    Full Text Available Anthrax toxin receptors 1 and 2 (ANTXR1 and ANTXR2 have a related integrin-like inserted (I domain which interacts with a metal cation that is coordinated by residue D683 of the protective antigen (PA subunit of anthrax toxin. The receptor-bound metal ion and PA residue D683 are critical for ANTXR1-PA binding. Since PA can bind to ANTXR2 with reduced affinity in the absence of metal ions, we reasoned that D683 mutant forms of PA might specifically interact with ANTXR2. We show here that this is the case. The differential ability of ANTXR1 and ANTXR2 to bind D683 mutant PA proteins was mapped to nonconserved receptor residues at the binding interface with PA domain 2. Moreover, a D683K mutant form of PA that bound specifically to human and rat ANTXR2 mediated killing of rats by anthrax lethal toxin, providing strong evidence for the physiological importance of ANTXR2 in anthrax disease pathogenesis.

  10. Snake Venom Metalloproteinases

    Directory of Open Access Journals (Sweden)

    Gâz Florea Şerban Andrei

    2016-03-01

    Full Text Available As more data are generated from proteome and transcriptome analysis revealing that metalloproteinases represent most of the Viperid and Colubrid venom components authors decided to describe in a short review a classification and some of the multiple activities of snake venom metalloproteinases. SVMPs are classified in three major classes (P-I, P-II and P-III classes based on the presence of various domain structures and according to their domain organization. Furthermore, P-II and P-III classes were separated in subclasses based on distinctive post-translational modifications. SVMPs are synthesized in a latent form, being activated through a Cys-switch mechanism similar to matrix metalloproteinases. Most of the metalloproteinases of the snake venom are responsible for the hemorrhagic events but also have fibrinogenolytic activity, poses apoptotic activity, activate blood coagulation factor II and X, inhibit platelet aggregation, demonstrating that SVMPs have multiple functions in addition to well-known hemorrhagic function.

  11. Exotic pet medicine I. Snakes.

    Science.gov (United States)

    Jacobson, E R

    1993-11-01

    Of the 6,000 extant species of reptiles, approximately 2500 are snakes. Several dozen species of snakes have become popular in the pet trade, and to meet the increased demand, more and more species are being bred in captivity. Along with this popularity comes the need for more sound veterinary expertise. Although much biomedical information on snakes exists in the literature and can be found in texts on reptile medicine, few reviews have tried to consolidate the literature on this subject. The purpose of this article is to bring together information on the most pertinent aspects of snake medicine and disease.

  12. Immunotoxins: The Role of the Toxin

    Directory of Open Access Journals (Sweden)

    David FitzGerald

    2013-08-01

    Full Text Available Immunotoxins are antibody-toxin bifunctional molecules that rely on intracellular toxin action to kill target cells. Target specificity is determined via the binding attributes of the chosen antibody. Mostly, but not exclusively, immunotoxins are purpose-built to kill cancer cells as part of novel treatment approaches. Other applications for immunotoxins include immune regulation and the treatment of viral or parasitic diseases. Here we discuss the utility of protein toxins, of both bacterial and plant origin, joined to antibodies for targeting cancer cells. Finally, while clinical goals are focused on the development of novel cancer treatments, much has been learned about toxin action and intracellular pathways. Thus toxins are considered both medicines for treating human disease and probes of cellular function.

  13. Novel receptors for bacterial protein toxins.

    Science.gov (United States)

    Schmidt, Gudula; Papatheodorou, Panagiotis; Aktories, Klaus

    2015-02-01

    While bacterial effectors are often directly introduced into eukaryotic target cells by various types of injection machines, toxins enter the cytosol of host cells from endosomal compartments or after retrograde transport via Golgi from the ER. A first crucial step of toxin-host interaction is receptor binding. Using optimized protocols and new methods novel toxin receptors have been identified, including metalloprotease ADAM 10 for Staphylococcus aureus α-toxin, laminin receptor Lu/BCAM for Escherichia coli cytotoxic necrotizing factor CNF1, lipolysis stimulated lipoprotein receptor (LSR) for Clostridium difficile transferase CDT and low-density lipoprotein receptor-related protein (LRP) 1 for Clostridium perfringens TpeL toxin. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Interplay between toxin transport and flotillin localization

    DEFF Research Database (Denmark)

    Pust, Sascha; Dyve, Anne Berit; Torgersen, Maria L

    2010-01-01

    The flotillin proteins are localized in lipid domains at the plasma membrane as well as in intracellular compartments. In the present study, we examined the importance of flotillin-1 and flotillin-2 for the uptake and transport of the bacterial Shiga toxin (Stx) and the plant toxin ricin and we...... investigated whether toxin binding and uptake were associated with flotillin relocalization. We observed a toxin-induced redistribution of the flotillins, which seemed to be regulated in a p38-dependent manner. Our experiments provide no evidence for a changed endocytic uptake of Stx or ricin in cells silenced...... for flotillin-1 or -2. However, the Golgi-dependent sulfation of both toxins was significantly reduced in flotillin knockdown cells. Interestingly, when the transport of ricin to the ER was investigated, we obtained an increased mannosylation of ricin in flotillin-1 and flotillin-2 knockdown cells. The toxicity...

  15. Snakes Have Feelings, Too: Elements of a Camp Snake Program.

    Science.gov (United States)

    Allen, Robert Ross

    2001-01-01

    A camp snake program can help campers overcome their fear of snakes, and people cannot truly enjoy nature when they carry a phobia about any one part of it. It can also help overcome prejudice by teaching truth and respect, instilling compassion, and helping campers develop empathy. Advice on catching, handling, identifying, keeping, and feeding…

  16. \\'The snake will swallow you': supernatural snakes and the creation ...

    African Journals Online (AJOL)

    \\'The snake will swallow you': supernatural snakes and the creation of the Khotso legend. Felicity Wood. Abstract. No Abstract. Indilinga: African Journal of Indigenous Knowledge Systems (IAJIKS) Vol. 4(1) 2005: 347-359. Full Text: EMAIL FULL TEXT EMAIL FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT.

  17. Conserved Arginines at the P-Protein Stalk Binding Site and the Active Site Are Critical for Ribosome Interactions of Shiga Toxins but Do Not Contribute to Differences in the Affinity of the A1 Subunits for the Ribosome.

    Science.gov (United States)

    Basu, Debaleena; Kahn, Jennifer N; Li, Xiao-Ping; Tumer, Nilgun E

    2016-12-01

    The A1 subunits of Shiga toxin 1 (Stx1A1) and Shiga toxin 2 (Stx2A1) interact with the conserved C termini of ribosomal-stalk P-proteins to remove a specific adenine from the sarcin/ricin loop. We previously showed that Stx2A1 has higher affinity for the ribosome and higher catalytic activity than Stx1A1. To determine if conserved arginines at the distal face of the active site contribute to the higher affinity of Stx2A1 for the ribosome, we mutated Arg172, Arg176, and Arg179 in both toxins. We show that Arg172 and Arg176 are more important than Arg179 for the depurination activity and toxicity of Stx1A1 and Stx2A1. Mutation of a single arginine reduced the depurination activity of Stx1A1 more than that of Stx2A1. In contrast, mutation of at least two arginines was necessary to reduce depurination by Stx2A1 to a level similar to that of Stx1A1. R176A and R172A/R176A mutations eliminated interaction of Stx1A1 and Stx2A1 with ribosomes and with the stalk, while mutation of Arg170 at the active site reduced the binding affinity of Stx1A1 and Stx2A1 for the ribosome, but not for the stalk. These results demonstrate that conserved arginines at the distal face of the active site are critical for interactions of Stx1A1 and Stx2A1 with the stalk, while a conserved arginine at the active site is critical for non-stalk-specific interactions with the ribosome. Arginine mutations at either site reduced ribosome interactions of Stx1A1 and Stx2A1 similarly, indicating that conserved arginines are critical for ribosome interactions but do not contribute to the higher affinity of Stx2A1 for the ribosome. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  18. ClanTox: a classifier of short animal toxins.

    Science.gov (United States)

    Naamati, Guy; Askenazi, Manor; Linial, Michal

    2009-07-01

    Toxins are detected in sporadic species along the evolutionary tree of the animal kingdom. Venomous animals include scorpions, snakes, bees, wasps, frogs and numerous animals living in the sea such as the stonefish, snail, jellyfish, hydra and more. Interestingly, proteins that share a common scaffold with animal toxins also exist in non-venomous species. However, due to their short length and primary sequence diversity, these, toxin-like proteins remain undetected by classical search engines and genome annotation tools. We construct a toxin classification machine and web server called ClanTox (Classifier of Animal Toxins) that is based on the extraction of sequence-driven features from the primary protein sequence followed by the application of a classification system trained on known animal toxins. For a given input list of sequences, from venomous or non-venomous settings, the ClanTox system predicts whether each sequence is toxin-like. ClanTox provides a ranked list of positively predicted candidates according to statistical confidence. For each protein, additional information is presented including the presence of a signal peptide, the number of cysteine residues and the associated functional annotations. ClanTox is a discovery-prediction tool for a relatively overlooked niche of toxin-like cell modulators, many of which are therapeutic agent candidates. The ClanTox web server is freely accessible at http://www.clantox.cs.huji.ac.il.

  19. Progressive Loss of Function in a Limb Enhancer during Snake Evolution

    Energy Technology Data Exchange (ETDEWEB)

    Kvon, Evgeny Z.; Kamneva, Olga K.; Melo, Uirá S.; Barozzi, Iros; Osterwalder, Marco; Mannion, Brandon J.; Tissières, Virginie; Pickle, Catherine S.; Plajzer-Frick, Ingrid; Lee, Elizabeth A.; Kato, Momoe; Garvin, Tyler H.; Akiyama, Jennifer A.; Afzal, Veena; Lopez-Rios, Javier; Rubin, Edward M.; Dickel, Diane E.; Pennacchio, Len A.; Visel, Axel

    2016-10-20

    The evolution of body shape is thought to be tightly coupled to changes in regulatory sequences, but specific molecular events associated with major morphological transitions in vertebrates have remained elusive. In this paper, we identified snake-specific sequence changes within an otherwise highly conserved long-range limb enhancer of Sonic hedgehog (Shh). Transgenic mouse reporter assays revealed that the in vivo activity pattern of the enhancer is conserved across a wide range of vertebrates, including fish, but not in snakes. Genomic substitution of the mouse enhancer with its human or fish ortholog results in normal limb development. In contrast, replacement with snake orthologs caused severe limb reduction. Synthetic restoration of a single transcription factor binding site lost in the snake lineage reinstated full in vivo function to the snake enhancer. Our results demonstrate changes in a regulatory sequence associated with a major body plan transition and highlight the role of enhancers in morphological evolution.

  20. Membrane invagination induced by Shiga toxin B-subunit

    DEFF Research Database (Denmark)

    Pezeshkian, W.; Hansen, Allan Grønhøj; Johannes, Ludger

    2016-01-01

    The bacterial Shiga toxin is composed of an enzymatically active A-subunit, and a receptor-binding homopentameric B-subunit (STxB) that mediates intracellular toxin trafficking. Upon STxB-mediated binding to the glycolipid globotriaosylceramide (Gb3) at the plasma membrane of target cells, Shiga...... toxin is internalized by clathrin-dependent and independent endocytosis. The formation of tubular membrane invaginations is an essential step in the clathrin-independent STxB uptake process. However, the mechanism by which STxB induces these invaginations has remained unclear. Using a combination of all...... toxin molecules then creates a tubular membrane invagination that drives toxin entry into the cell. This mechanism requires: (1) a precise molecular architecture of the STxB binding sites; (2) a fluid bilayer in order for the tubular invagination to form. Although, STxB binding to the membrane requires...

  1. Snake venomic of Crotalus durissus terrificus--correlation with pharmacological activities.

    Science.gov (United States)

    Georgieva, Dessislava; Ohler, Michaela; Seifert, Jana; von Bergen, Martin; Arni, Raghuvir K; Genov, Nicolay; Betzel, Christian

    2010-05-07

    The snake venomic of Crotalus durissus terrificus was analyzed by 2-D and 1-D electrophoresis and subsequent MS/MS and enzymatic assays. The venomic of the South American rattlesnake comprises toxins from seven protein families: phospholipases A(2), serine proteinases, ecto-5'-nucleotidases, metalloproteinases, nerve growth factors, phosphodiesterases, and glutaminyl cyclase. The venom toxin composition correlates with the clinical manifestation of the crotalinae snake bites and explains pathological effects of the venom such as neurotoxicity, systemic myonecrosis, hemostatic disorders, myoglobinuria, and acute renal failure. The vast majority of toxins are potentially involved in neurotoxicity, myotoxicity, and coagulopathy. The predominant venom components are neurotoxic phospholipases A(2) and serine proteinases. The venom is a rich source of 5'-nucleotidases (7.8% of the identified toxins) inducing hemostatic disorders. Analysis of the venom protein composition provided a catalogue for secreted toxins. The venomic composition of Crotalus d. terrificus and venom gland transcriptome of the synonymous subspecies Crotalus d. collilineatus show differences in the occurrence of protein families and in the abundance of toxins. Some of the venom components identified by the proteomic analysis were not reported in the transcriptome of the Crotalus d. collilineatus venom gland. Enzymatic activities of the Crotalus d. terrificus venom were determined and correlated with the proteomic composition.

  2. Runaway snakes in TEXTOR-94

    NARCIS (Netherlands)

    Entrop, I.; R. Jaspers,; Cardozo, N. J. L.; Finken, K.H.

    1999-01-01

    Observations of a runaway beam confined in an island-like structure, a so-called runaway snake, are reported. The observations are made in TEXTOR-94 by measurement of synchrotron radiation emitted by these runaways. A full poloidal View allows for the study of the synchrotron pattern of the snake to

  3. Veterinary management of snake reproduction.

    Science.gov (United States)

    Stahl, Scott J

    2002-09-01

    The reptile veterinarian should approach the breeder with a comprehensive plan involving a review of proper husbandry, nutrition, record keeping, and a thorough prebreeding evaluation of the snakes. In addition, an evaluation of the reproductive strategy, assistance with confirming and monitoring gestation, and a review of potential reproductive complications will help to prepare the snake owner for a successful breeding season.

  4. Snake-Deterministic Tiling Systems

    Science.gov (United States)

    Lonati, Violetta; Pradella, Matteo

    The concept of determinism, while clear and well assessed for string languages, is still matter of research as far as picture languages are concerned. We introduce here a new kind of determinism, called snake, based on the boustrophedonic scanning strategy, that is a natural scanning strategy used by many algorithms on 2D arrays and pictures. We consider a snake-deterministic variant of tiling systems, which defines the so-called Snake-DREC class of languages. Snake-DREC properly extends the more traditional approach of diagonal-based determinism, used e.g. by deterministic tiling systems, and by online tessellation automata. Our main result is showing that the concept of snake-determinism of tiles coincides with row (or column) unambiguity.

  5. Botulinum toxin: mechanisms of action

    OpenAIRE

    Dirk Dressler; Fereshte Adib Saberi; Egberto Reis Barbosa

    2005-01-01

    This review describes therapeutically relevant mechanisms of action of botulinum toxin (BT). BT's molecular mode of action includes extracellular binding to glycoproteine structures on cholinergic nerve terminals and intracellular blockade of the acetylcholine secretion. BT affects the spinal stretch reflex by blockade of intrafusal muscle fibres with consecutive reduction of Ia/II afferent signals and muscle tone without affecting muscle strength (reflex inhibition). This mechanism allows fo...

  6. Sea Anemone Toxins Affecting Potassium Channels

    Science.gov (United States)

    Diochot, Sylvie; Lazdunski, Michel

    The great diversity of K+ channels and their wide distribution in many tissues are associated with important functions in cardiac and neuronal excitability that are now better understood thanks to the discovery of animal toxins. During the past few decades, sea anemones have provided a variety of toxins acting on voltage-sensitive sodium and, more recently, potassium channels. Currently there are three major structural groups of sea anemone K+ channel (SAK) toxins that have been characterized. Radioligand binding and electrophysiological experiments revealed that each group contains peptides displaying selective activities for different subfamilies of K+ channels. Short (35-37 amino acids) peptides in the group I display pore blocking effects on Kv1 channels. Molecular interactions of SAK-I toxins, important for activity and binding on Kv1 channels, implicate a spot of three conserved amino acid residues (Ser, Lys, Tyr) surrounded by other less conserved residues. Long (58-59 amino acids) SAK-II peptides display both enzymatic and K+ channel inhibitory activities. Medium size (42-43 amino acid) SAK-III peptides are gating modifiers which interact either with cardiac HERG or Kv3 channels by altering their voltage-dependent properties. SAK-III toxins bind to the S3C region in the outer vestibule of Kv channels. Sea anemones have proven to be a rich source of pharmacological tools, and some of the SAK toxins are now useful drugs for the diagnosis and treatment of autoimmune diseases.

  7. Snake bite in Nigeria.

    Science.gov (United States)

    Habib, A G; Gebi, U I; Onyemelukwe, G C

    2001-09-01

    Four families of venomous snakes are found in Nigeria--Viperidae, Elapidae, Colubridae and Actraspididae but three species carpet viper (Echis ocellatus), black-necked spitting cobra (Naja nigricollis) and puff adder (Bitis arietans), belonging to the first two families, are the most important snakes associated with envenoming in Nigeria. The incidence of bites has been reported as 497 per 100,000 population per year with a 12 percent natural mortality, with Echis ocellatus accounting for at least 66 percent in certain foci. Bites occur more often while victims were farming, herding or walking although the spitting cobra may bite victims who roll upon it in their sleep. Carpet viper venom contains a prothrombin activating procoagulant, haemorrhagin and cytolytic fractions which cause haemorrhage, incoagulable blood, shock and local reactions/ necrosis. The spitting cobra bite manifests with local tissue reaction and occassionally with bleeding from the site of bite, but no classic neurotoxic feature has been observed except following Egyptian cobra (N. haje) bites. Cardiotoxicity and renal failure may occassionally occur following bites by the carpet viper and the puff adder. In the laboratory, haematological and other features are noted and immunodiagnosis has a role in species identification. Immobilisation of the bitten limb is probably the single most important first aid measure. Antivenom should be used cautiously when indicated. As only 8.5 percent of snake bite victims attend hospitals in Nigeria, health education should be the main preventive measure, mean-while, the study of immunisation of occupationally predisposed individuals in endemic areas should be intensified. A new Fab fragment antivenom specific to Nigerian Echis ocellatus was investigated clinically, just as the local herbs-Aristolochia spp, Guiera spp and Schummaniophyton spp are investigated experimentally.

  8. Snake City North

    OpenAIRE

    Johannesson, Tomas

    2005-01-01

    SkivproduktionJonas Kullhammar Quartet with Norrbotten Big Band – Snake City North, 2005Utgiven av Moserobie music production 2005Inspelad av Göran Stegborn och Tomas JohannessonMixad av Göran StegbornMastrad av Claes PerssonGrammisnominerad till årets jazzskiva 2005Musiker:Jonas Kullhammar: Tenor SaxophoneJonas Holgersson: DrumsTorbjörn Gulz: PianoTorbjörn Zetterberg: BassNorrbotten Big Band:Trumpets: Bo Strandberg, Magnus Ekholm, Tapio MaunuvaaraTrumpet & Fluegelhorn: Dan Johansson (2,5...

  9. Activation of RAW264.7 mouse macrophage cells in vitro through treatment with recombinant ricin toxin-binding subunit B: involvement of protein tyrosine, NF-κB and JAK-STAT kinase signaling pathways.

    Science.gov (United States)

    Xu, Na; Yuan, Hongyan; Liu, Wensen; Li, Songyan; Liu, Yang; Wan, Jiayu; Li, Xiaoyan; Zhang, Rui; Chang, Yaping

    2013-09-01

    Ricin toxin-binding subunit B (RTB) is a galactose-binding lectin protein. In the present study, we investigated the effects of RTB on inducible nitric oxide (NO) synthase (iNOS), interleukin (IL)-6 and tumor necrosis factor (TNF)-α, as well as the signal transduction mechanisms involved in recombinant RTB-induced macrophage activation. RAW264.7 macrophages were treated with RTB. The results revealed that the mRNA and protein expression of iNOS was increased in the recombinant RTB-treated macrophages. TNF-α production was observed to peak at 20 h, whereas the production of IL-6 peaked at 24 h. In another set of cultures, the cells were co-incubated with RTB and the tyrosine kinase inhibitor, genistein, the phosphatidylinositol 3-kinase (PI3K) inhibitor, LY294002, the p42/44 inhibitor, PD98059, the p38 inhibitor, SB203580, the JNK inhibitor, SP600125, the protein kinase C (PKC) inhibitor, staurosporine, the JAK2 inhibitor, tyrphostin (AG490), or the NOS inhibitor, L-NMMA. The recombinant RTB-induced production of NO, TNF-α and IL-6 was inhibited in the macrophages treated with the pharmacological inhibitors genistein, LY294002, staurosporine, AG490, SB203580 and BAY 11-7082, indicating the possible involvement of protein tyrosine kinases, PI3K, PKC, JAK2, p38 mitogen-activated protein kinase (MAPK) and nuclear factor (NF)-κB in the above processes. A phosphoprotein analysis identified tyrosine phosphorylation targets that were uniquely induced by recombinant RTB and inhibited following treatment with genistein; some of these proteins are associated with the downstream cascades of activated JAK-STAT and NF-κB receptors. Our data may help to identify the most important target molecules for the development of novel drug therapies.

  10. Identification of Immunoreactive Peptides of Toxins to Simultaneously Assess the Neutralization Potency of Antivenoms against Neurotoxicity and Cytotoxicity of Naja atra Venom.

    Science.gov (United States)

    Liu, Bin-Sin; Wu, Wen-Guey; Lin, Min-Han; Li, Chi-Han; Jiang, Bo-Rong; Wu, Suh-Chin; Leng, Chih-Hsiang; Sung, Wang-Chou

    2017-12-25

    Assessing the neutralization capability of nonlethal but medically relevant toxins in venom has been a challenging task. Nowadays, neutralization efficacy is evaluated based simply on the survival rates of animals injected with antivenom together with a predefined dose of venom, which can determine potency against neurotoxicity but not validate the capability to neutralize cytotoxin-induced complications. In this study, a high correlation with in-vivo and in-vitro neutralization assays was established using the immunoreactive peptides identified from short-chain neurotoxin and cytotoxin A3. These peptides contain conserved residues associated with toxin activities and a competition assay indicated that these peptides could specifically block the antibody binding to toxin and affect the neutralization potency of antivenom. Moreover, the titers of peptide-specific antibody in antivenoms or mouse antisera were determined by enzyme-linked immunosorbent assay (ELISA) simultaneously, and the results indicated that Taiwanese bivalent antivenom (BAV) and Vietnamese snake antivenom-Naja (SAV-Naja) exhibited superior neutralization potency against the lethal effect of short-chain neurotoxin (sNTX) and cytotoxicity of cardiotoxin/cytotoxin (CTX), respectively. Thus, the reported peptide ELISA shows not only its potential for antivenom prequalification use, but also its capability of justifying the cross-neutralization potency of antivenoms against Naja atra venom toxicity.

  11. Identification of Immunoreactive Peptides of Toxins to Simultaneously Assess the Neutralization Potency of Antivenoms against Neurotoxicity and Cytotoxicity of Naja atra Venom

    Directory of Open Access Journals (Sweden)

    Bing-Sin Liu

    2017-12-01

    Full Text Available Assessing the neutralization capability of nonlethal but medically relevant toxins in venom has been a challenging task. Nowadays, neutralization efficacy is evaluated based simply on the survival rates of animals injected with antivenom together with a predefined dose of venom, which can determine potency against neurotoxicity but not validate the capability to neutralize cytotoxin-induced complications. In this study, a high correlation with in-vivo and in-vitro neutralization assays was established using the immunoreactive peptides identified from short-chain neurotoxin and cytotoxin A3. These peptides contain conserved residues associated with toxin activities and a competition assay indicated that these peptides could specifically block the antibody binding to toxin and affect the neutralization potency of antivenom. Moreover, the titers of peptide-specific antibody in antivenoms or mouse antisera were determined by enzyme-linked immunosorbent assay (ELISA simultaneously, and the results indicated that Taiwanese bivalent antivenom (BAV and Vietnamese snake antivenom-Naja (SAV-Naja exhibited superior neutralization potency against the lethal effect of short-chain neurotoxin (sNTX and cytotoxicity of cardiotoxin/cytotoxin (CTX, respectively. Thus, the reported peptide ELISA shows not only its potential for antivenom prequalification use, but also its capability of justifying the cross-neutralization potency of antivenoms against Naja atra venom toxicity.

  12. Clostridium perfringens delta toxin is sequence related to beta toxin, NetB, and Staphylococcus pore-forming toxins, but shows functional differences.

    Directory of Open Access Journals (Sweden)

    Maria Manich

    Full Text Available Clostridium perfringens produces numerous toxins, which are responsible for severe diseases in man and animals. Delta toxin is one of the three hemolysins released by a number of C. perfringens type C and possibly type B strains. Delta toxin was characterized to be cytotoxic for cells expressing the ganglioside G(M2 in their membrane. Here we report the genetic characterization of Delta toxin and its pore forming activity in lipid bilayers. Delta toxin consists of 318 amino acids, its 28 N-terminal amino acids corresponding to a signal peptide. The secreted Delta toxin (290 amino acids; 32619 Da is a basic protein (pI 9.1 which shows a significant homology with C. perfringens Beta toxin (43% identity, with C. perfringens NetB (40% identity and, to a lesser extent, with Staphylococcus aureus alpha toxin and leukotoxins. Recombinant Delta toxin showed a preference for binding to G(M2, in contrast to Beta toxin, which did not bind to gangliosides. It is hemolytic for sheep red blood cells and cytotoxic for HeLa cells. In artificial diphytanoyl phosphatidylcholine membranes, Delta and Beta toxin formed channels. Conductance of the channels formed by Delta toxin, with a value of about 100 pS to more than 1 nS in 1 M KCl and a membrane potential of 20 mV, was higher than those formed by Beta toxin and their distribution was broader. The results of zero-current membrane potential measurements and single channel experiments suggest that Delta toxin forms slightly anion-selective channels, whereas the Beta toxin channels showed a preference for cations under the same conditions. C. perfringens Delta toxin shows a significant sequence homolgy with C. perfringens Beta and NetB toxins, as well as with S. aureus alpha hemolysin and leukotoxins, but exhibits different channel properties in lipid bilayers. In contrast to Beta toxin, Delta toxin recognizes G(M2 as receptor and forms anion-selective channels.

  13. Biological and molecular properties of yellow venom of the Amazonian coral snake Micrurus surinamensis.

    Science.gov (United States)

    Oliveira, Fabiana da Rocha; Noronha, Maria das Dores Nogueira; Lozano, Jorge Luis Lopez

    2017-01-01

    The coral snake Micrurus surinamensis, which is widely distributed throughout Amazonia, has a neurotoxic venom. It is important to characterize the biological and molecular properties of this venom in order to develop effective antitoxins. Toxins from the venom of M. surinamensis were analyzed by two-dimensional polyacrylamide gel electrophoresis and their neurotoxic effects in vivo were evaluated. Most proteins in the venom had masses < 14kDa, low phospholipase A2 activity, and no proteolytic activity. The toxins inhibited the coagulation cascade. The venom had neurotoxic effects in mice, with a median lethal dose upon intravenous administration of 700 µg/kg. Immunogenic studies revealed abundant cross-reactivity of antielapidic serum with 14kDa toxins and limited cross-reactivity with toxins < 10kDa. These results indicate that antielapidic serum against M. surinamensis venom has weak potency (0.35mg/ml) in mice.

  14. Biological and molecular properties of yellow venom of the Amazonian coral snake Micrurus surinamensis

    Directory of Open Access Journals (Sweden)

    Fabiana da Rocha Oliveira

    Full Text Available Abstract INTRODUCTION: The coral snake Micrurus surinamensis, which is widely distributed throughout Amazonia, has a neurotoxic venom. It is important to characterize the biological and molecular properties of this venom in order to develop effective antitoxins. METHODS: Toxins from the venom of M. surinamensis were analyzed by two-dimensional polyacrylamide gel electrophoresis and their neurotoxic effects in vivo were evaluated. RESULTS AND CONCLUSIONS: Most proteins in the venom had masses < 14kDa, low phospholipase A2 activity, and no proteolytic activity. The toxins inhibited the coagulation cascade. The venom had neurotoxic effects in mice, with a median lethal dose upon intravenous administration of 700 µg/kg. Immunogenic studies revealed abundant cross-reactivity of antielapidic serum with 14kDa toxins and limited cross-reactivity with toxins < 10kDa. These results indicate that antielapidic serum against M. surinamensis venom has weak potency (0.35mg/ml in mice.

  15. Venomic Analysis of the Poorly Studied Desert Coral Snake, Micrurus tschudii tschudii, Supports the 3FTx/PLA2 Dichotomy across Micrurus Venoms

    OpenAIRE

    Sanz, Libia; Pla, Davinia; P?rez, Alicia; Rodr?guez, Yania; Zavaleta, Alfonso; Salas, Maria; Lomonte, Bruno; Calvete, Juan J.

    2016-01-01

    The venom proteome of the poorly studied desert coral snake Micrurus tschudii tschudii was unveiled using a venomic approach, which identified ≥38 proteins belonging to only four snake venom protein families. The three-finger toxins (3FTxs) constitute, both in number of isoforms (~30) and total abundance (93.6% of the venom proteome), the major protein family of the desert coral snake venom. Phospholipases A₂ (PLA₂s; seven isoforms, 4.1% of the venom proteome), 1-3 Kunitz-type proteins (1.6%)...

  16. Minor snake venom proteins: Structure, function and potential applications.

    Science.gov (United States)

    Boldrini-França, Johara; Cologna, Camila Takeno; Pucca, Manuela Berto; Bordon, Karla de Castro Figueiredo; Amorim, Fernanda Gobbi; Anjolette, Fernando Antonio Pino; Cordeiro, Francielle Almeida; Wiezel, Gisele Adriano; Cerni, Felipe Augusto; Pinheiro-Junior, Ernesto Lopes; Shibao, Priscila Yumi Tanaka; Ferreira, Isabela Gobbo; de Oliveira, Isadora Sousa; Cardoso, Iara Aimê; Arantes, Eliane Candiani

    2017-04-01

    Snake venoms present a great diversity of pharmacologically active compounds that may be applied as research and biotechnological tools, as well as in drug development and diagnostic tests for certain diseases. The most abundant toxins have been extensively studied in the last decades and some of them have already been used for different purposes. Nevertheless, most of the minor snake venom protein classes remain poorly explored, even presenting potential application in diverse areas. The main difficulty in studying these proteins lies on the impossibility of obtaining sufficient amounts of them for a comprehensive investigation. The advent of more sensitive techniques in the last few years allowed the discovery of new venom components and the in-depth study of some already known minor proteins. This review summarizes information regarding some structural and functional aspects of low abundant snake venom proteins classes, such as growth factors, hyaluronidases, cysteine-rich secretory proteins, nucleases and nucleotidases, cobra venom factors, vespryns, protease inhibitors, antimicrobial peptides, among others. Some potential applications of these molecules are discussed herein in order to encourage researchers to explore the full venom repertoire and to discover new molecules or applications for the already known venom components. Copyright © 2016. Published by Elsevier B.V.

  17. The venom-gland transcriptome of the eastern coral snake (Micrurus fulvius) reveals high venom complexity in the intragenomic evolution of venoms.

    Science.gov (United States)

    Margres, Mark J; Aronow, Karalyn; Loyacano, Jacob; Rokyta, Darin R

    2013-08-02

    Snake venom is shaped by the ecology and evolution of venomous species, and signals of positive selection in toxins have been consistently documented, reflecting the role of venoms as an ecologically critical phenotype. New World coral snakes (Elapidae) are represented by three genera and over 120 species and subspecies that are capable of causing significant human morbidity and mortality, yet coral-snake venom composition is poorly understood in comparison to that of Old World elapids. High-throughput sequencing is capable of identifying thousands of loci, while providing characterizations of expression patterns and the molecular evolutionary forces acting within the venom gland. We describe the de novo assembly and analysis of the venom-gland transcriptome of the eastern coral snake (Micrurus fulvius). We identified 1,950 nontoxin transcripts and 116 toxin transcripts. These transcripts accounted for 57.1% of the total reads, with toxins accounting for 45.8% of the total reads. Phospholipases A(2) and three-finger toxins dominated expression, accounting for 86.0% of the toxin reads. A total of 15 toxin families were identified, revealing venom complexity previously unknown from New World coral snakes. Toxins exhibited high levels of heterozygosity relative to nontoxins, and overdominance may favor gene duplication leading to the fixation of advantageous alleles. Phospholipase A(2) expression was uniformly distributed throughout the class while three-finger toxin expression was dominated by a handful of transcripts, and phylogenetic analyses indicate that toxin divergence may have occurred following speciation. Positive selection was detected in three of the four most diverse toxin classes, suggesting that venom diversification is driven by recurrent directional selection. We describe the most complete characterization of an elapid venom gland to date. Toxin gene duplication may be driven by heterozygote advantage, as the frequency of polymorphic toxin loci was

  18. Snake Venomics and Antivenomics of Bothrops diporus, a Medically Important Pitviper in Northeastern Argentina

    Science.gov (United States)

    Gay, Carolina; Sanz, Libia; Calvete, Juan J.; Pla, Davinia

    2015-01-01

    Snake species within genus Bothrops are responsible for more than 80% of the snakebites occurring in South America. The species that cause most envenomings in Argentina, B. diporus, is widely distributed throughout the country, but principally found in the Northeast, the region with the highest rates of snakebites. The venom proteome of this medically relevant snake was unveiled using a venomic approach. It comprises toxins belonging to fourteen protein families, being dominated by PI- and PIII-SVMPs, PLA2 molecules, BPP-like peptides, L-amino acid oxidase and serine proteinases. This toxin profile largely explains the characteristic pathophysiological effects of bothropic snakebites observed in patients envenomed by B. diporus. Antivenomic analysis of the SAB antivenom (Instituto Vital Brazil) against the venom of B. diporus showed that this pentabothropic antivenom efficiently recognized all the venom proteins and exhibited poor affinity towards the small peptide (BPPs and tripeptide inhibitors of PIII-SVMPs) components of the venom. PMID:26712790

  19. Snake Venomics and Antivenomics of Bothrops diporus, a Medically Important Pitviper in Northeastern Argentina.

    Science.gov (United States)

    Gay, Carolina; Sanz, Libia; Calvete, Juan J; Pla, Davinia

    2015-12-25

    Snake species within genus Bothrops are responsible for more than 80% of the snakebites occurring in South America. The species that cause most envenomings in Argentina, B. diporus, is widely distributed throughout the country, but principally found in the Northeast, the region with the highest rates of snakebites. The venom proteome of this medically relevant snake was unveiled using a venomic approach. It comprises toxins belonging to fourteen protein families, being dominated by PI- and PIII-SVMPs, PLA₂ molecules, BPP-like peptides, L-amino acid oxidase and serine proteinases. This toxin profile largely explains the characteristic pathophysiological effects of bothropic snakebites observed in patients envenomed by B. diporus. Antivenomic analysis of the SAB antivenom (Instituto Vital Brazil) against the venom of B. diporus showed that this pentabothropic antivenom efficiently recognized all the venom proteins and exhibited poor affinity towards the small peptide (BPPs and tripeptide inhibitors of PIII-SVMPs) components of the venom.

  20. Cross-neutralisation of the neurotoxic effects of Egyptian cobra venom with commercial tiger snake antivenom.

    Science.gov (United States)

    Kornhauser, Rachelle; Isbister, Geoffrey K; O'Leary, Margaret A; Mirtschin, Peter; Dunstan, Nathan; Hodgson, Wayne C

    2013-02-01

    Cross-neutralisation has been demonstrated for haemorrhagic venoms including Echis spp. and Cerastes spp. and for Australia elapid procoagulant toxins. A previous study showed that commercial tiger snake antivenom (TSAV) was able to neutralise the systemic effects of the Egyptian cobra, Naja haje, in vivo but it is unclear if this was true cross-neutralisation. The aim of the current study was to determine whether TSAV can neutralise the in vitro neurotoxic effects of N. haje venom. Both Notechis scutatus (10 μg/ml) and N. haje (10 μg/ml) venoms caused inhibition of indirect (supramaximal V, 0.1 Hz, 0.2 msec.) twitches of the chick biventer cervicis nerve-muscle preparation with t(90) values (i.e. the time to produce 90% inhibition of the original twitch height) of 26 ± 1 min. (n = 4) and 36 ± 4 min.; (n = 4). This effect at 10 μg/ml was significantly attenuated by the prior addition of TSAV (5 U/ml). A comparison of the reverse-phase HPLC profiles of both venoms showed some similarities with peak elution times, and SDS-PAGE analysis elucidated comparable bands across both venoms. Further analysis using Western immunoblotting indicated TSAV was able to detect N. haje venom, and enzyme immunoassay showed that in-house biotinylated polyclonal monovalent N. scutatus antibodies were able to detect N. haje venom. These findings demonstrate cross-neutralisation between different and geographically separated snakes supporting potential immunological similarities in snake toxin groups for a large range of snakes. This provides more evidence that antivenoms could be developed against specific toxin groups to cover a large range of snakes. © 2012 The Authors Basic & Clinical Pharmacology & Toxicology © 2012 Nordic Pharmacological Society.

  1. Natural History of Pseudoboine Snakes

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    Marília P. Gaiarsa

    2013-01-01

    Full Text Available Even though natural history information is crucial for answering key ecological, evolutionary, and conservation questions, basic studies are still lacking for Neotropical snakes. This study aims at contributing to the knowledge of the Neotropical tribe Pseudoboini, based on literature data, analysis of museum specimens and unpublished data. The tribe is mainly composed of moderate-sized snakes, although small and large-sized snakes also occur in the clade. Mean fecundity ranged from two (Rodriguesophis iglesiasi to 29 eggs (Clelia plumbea and the species are predominantly terrestrial and nocturnal. Most species are diet specialists and lizards are the most commonly consumed prey (found in the diet of 29 species, followed by small mammals (consumed by 20 species and snakes (consumed by 18 species. Although the tribe Pseudoboini appears to be well studied, for 15 species (32% only a small amount of information or none was available. We hope that our study can motivate research on the least known species.

  2. Interplay between toxin transport and flotillin localization.

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    Sascha Pust

    Full Text Available The flotillin proteins are localized in lipid domains at the plasma membrane as well as in intracellular compartments. In the present study, we examined the importance of flotillin-1 and flotillin-2 for the uptake and transport of the bacterial Shiga toxin (Stx and the plant toxin ricin and we investigated whether toxin binding and uptake were associated with flotillin relocalization. We observed a toxin-induced redistribution of the flotillins, which seemed to be regulated in a p38-dependent manner. Our experiments provide no evidence for a changed endocytic uptake of Stx or ricin in cells silenced for flotillin-1 or -2. However, the Golgi-dependent sulfation of both toxins was significantly reduced in flotillin knockdown cells. Interestingly, when the transport of ricin to the ER was investigated, we obtained an increased mannosylation of ricin in flotillin-1 and flotillin-2 knockdown cells. The toxicity of both toxins was twofold increased in flotillin-depleted cells. Since BFA (Brefeldin A inhibits the toxicity even in flotillin knockdown cells, the retrograde toxin transport is apparently still Golgi-dependent. Thus, flotillin proteins regulate and facilitate the retrograde transport of Stx and ricin.

  3. Crotoxin from Crotalus durissus terrificus snake venom induces the release of glutamate from cerebrocortical synaptosomes via N and P/Q calcium channels.

    Science.gov (United States)

    Lomeo, Rosangela da Silva; Gonçalves, Ana Paula de Faria; da Silva, Carolina Nunes; de Paula, André Tunes; Costa Santos, Danielle Oliveira; Fortes-Dias, Consuelo Latorre; Gomes, Dawidson Assis; de Lima, Maria Elena

    2014-07-01

    Crotoxin (Crtx), the main toxin in the venom of Crotalus durissus terrificus snake, is a heterodimer with a basic subunit, CB, and an acidic subunit, CA. CB is a phospholipase A2 that depends on CA to specifically bind to the cell membrane. This toxin acts in the central nervous system (CNS) causing chronic seizure effects and other cytotoxic effects. Here, we report its action on glutamate release in rat cerebral cortex synaptosomes. Aiming at a better understanding of the mechanism of action of Crtx, calcium channel blockers were used and internalization studies were performed in cerebellar granule neurons. Our results show that Crtx induces calcium-dependent glutamate release via N and P/Q calcium channels. In addition, the CB subunit of Crtx is shown to be internalized. This internalization does not depend on the presence of CA subunit neither on the PLA2 activity of CB. A correlation between CB internalization and glutamate release remains to be established. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Recombinant snake venom prothrombin activators

    OpenAIRE

    L?vgren, Ann

    2012-01-01

    Three prothrombin activators; ecarin, which was originally isolated from the venom of the saw-scaled viper Echis carinatus, trocarin from the rough-scaled snake Tropidechis carinatus, and oscutarin from the Taipan snake Oxyuranus scutellatus, were expressed in mammalian cells with the purpose to obtain recombinant prothrombin activators that could be used to convert prothrombin to thrombin. We have previously reported that recombinant ecarin can efficiently generate thrombin without the need ...

  5. Differential transcript profile of inhibitors with potential anti-venom role in the liver of juvenile and adult Bothrops jararaca snake

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    Cícera Maria Gomes

    2017-04-01

    Full Text Available Background Snakes belonging to the Bothrops genus are vastly distributed in Central and South America and are responsible for most cases of reported snake bites in Latin America. The clinical manifestations of the envenomation caused by this genus are due to three major activities—proteolytic, hemorrhagic and coagulant—mediated by metalloproteinases, serine proteinases, phospholipases A2 and other toxic compounds present in snake venom. Interestingly, it was observed that snakes are resistant to the toxic effects of its own and other snake’s venoms. This natural immunity may occur due the absence of toxin target or the presence of molecules in the snake plasma able to neutralize such toxins. Methods In order to identify anti-venom molecules, we construct a cDNA library from the liver of B. jararaca snakes. Moreover, we analyzed the expression profile of four molecules—the already known anti-hemorrhagic factor Bj46a, one gamma-phospholipase A2 inhibitor, one inter-alpha inhibitor and one C1 plasma protease inhibitor—in the liver of juvenile and adult snakes by qPCR. Results The results revealed a 30-fold increase of gamma-phospholipase A2 inhibitor and a minor increase of the inter-alpha inhibitor (5-fold and of the C1 inhibitor (3-fold in adults. However, the Bj46a factor seems to be equally transcribed in adults and juveniles. Discussion The results suggest the up-regulation of different inhibitors observed in the adult snakes might be a physiological adaptation to the recurrent contact with their own and even other snake’s venoms throughout its lifespan. This is the first comparative analysis of ontogenetic variation of expression profiles of plasmatic proteins with potential anti-venom activities of the venomous snake B. jararaca. Furthermore, the present data contributes to the understanding of the natural resistance described in these snakes.

  6. Cellular Entry of Clostridium perfringens Iota-Toxin and Clostridium botulinum C2 Toxin

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    Masaya Takehara

    2017-08-01

    Full Text Available Clostridium perfringens iota-toxin and Clostridium botulinum C2 toxin are composed of two non-linked proteins, one being the enzymatic component and the other being the binding/translocation component. These latter components recognize specific receptors and oligomerize in plasma membrane lipid-rafts, mediating the uptake of the enzymatic component into the cytosol. Enzymatic components induce actin cytoskeleton disorganization through the ADP-ribosylation of actin and are responsible for cell rounding and death. This review focuses upon the recent advances in cellular internalization of clostridial binary toxins.

  7. Snakes exhibit tissue-specific variation in cardiotonic steroid sensitivity of Na+/K+-ATPase.

    Science.gov (United States)

    Mohammadi, Shabnam; Petschenka, Georg; French, Susannah S; Mori, Akira; Savitzky, Alan H

    2018-03-01

    Toads are among several groups of organisms chemically defended with lethal concentrations of cardiotonic steroids. As a result, most predators that prey on amphibians avoid toads. However, several species of snakes have gained resistance-conferring mutations of Na+/K+-ATPase, the molecular target of cardiotonic steroids, and can feed on toads readily. Despite recent advances in our understanding of this adaptation at the genetic level, we have lacked functional evidence for how mutations of Na+/K+-ATPase account for cardiotonic steroid resistance in snake tissues. To address this issue, it is necessary to determine how the Na+/K+-ATPases of snakes react to the toxins. Some tissues might have Na+/K+-ATPases that are more susceptible than others and can thus provide clues about how the toxins influence organismal function. Here we provide a mechanistic link between observed Na+/K+-ATPase substitutions and observed resistance using actual snake Na+/K+-ATPases. We used an in vitro approach to determine the tissue-specific levels of sensitivity to cardiotonic steroids in select resistant and non-resistant snakes. We compared the sensitivities of select tissues within and between species. Our results suggest that resistant snakes contain highly resistant Na+/K+-ATPases in their heart and kidney, both of which rely heavily on the enzymes to function, whereas tissues that do not rely as heavily on Na+/K+-ATPases or might be protected from cardiotonic steroids by other means (liver, gut, and brain) contain non-resistant forms of the enzyme. This study reveals functional evidence that tissue-level target-site insensitivity to cardiotonic steroids varies not only among species but also across tissues within resistant taxa. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Cutaneous Chromatophoromas in Captive Snakes.

    Science.gov (United States)

    Muñoz-Gutiérrez, J F; Garner, M M; Kiupel, M

    2016-11-01

    Chromatophoromas are neoplasms arising from pigment-bearing cells (chromatophores) of the dermis. While isolated cases have been reported in the literature, the prevalence and biological behavior of chromatophoromas in snakes are unknown. Forty-two chromatophoromas were identified among 4663 submissions (0.9%) to a private diagnostic laboratory in a 16-year period. The most commonly affected snakes were colubrids (23 cases, 55%) and vipers (8 cases, 19%). The San Francisco garter snake was the most commonly affected species (6 cases; 14% of all affected snake species and 3.7% of all garter snake submissions). No sex predilection was found. The age of 28 snakes ranged from 5 to 27 years. Single cutaneous chromatophoromas were most commonly observed and presented as pigmented cutaneous masses or plaques along any body segment. Euthanasia or death due to progressive neoplastic disease or metastasis was reported in 8 (19%) and 4 (10%) cases, respectively. The survival time of 4 animals ranged from 4 to 36 months. Microscopically, xanthophoromas, iridophoromas, melanocytic neoplasms, and mixed chromatophoromas were identified, with melanocytic neoplasms being most common. Microscopic examination alone was generally sufficient for the diagnosis of chromatophoroma, but immunohistochemistry for S-100 and PNL-2 may be helpful for diagnosing poorly pigmented cases. Moderate to marked nuclear atypia appears to be consistently present in cutaneous chromatophoromas with a high risk of metastasis, while mitotic count, lymphatic invasion, the level of infiltration, and the degree of pigmentation or ulceration were not reliable predictors of metastasis. © The Author(s) 2016.

  9. A Rare Case Series of Ischemic Stroke Following Russell’s Viper Snake Bite in India

    Directory of Open Access Journals (Sweden)

    Venkata Krishna Pothukuchi

    2018-01-01

    Full Text Available Snakebite is an important medical problem in India. Among their various manifestations, cerebral complications are uncommonly found in literature. Moreover, Ischemic stroke following snake bite is quite rare. Here we report a case series of two such cases that developed neurological manifestations following Russell’s viper bite. On computerized tomography (CT scan of brain; cerebral infarcts were revealed. Their likely mechanisms are discussed in present study which include disseminated intravascular coagulation, toxin induced vasculitis and endothelial damage.

  10. Cloning and characterization of Manduca sexta and Plutella xylostella midgut aminopeptidase N enzymes related to Bacillus thuringiensis toxin-binding proteins.

    Science.gov (United States)

    Denolf, P; Hendrickx, K; Van Damme, J; Jansens, S; Peferoen, M; Degheele, D; Van Rie, J

    1997-09-15

    We report the purification, cloning and characterization of an aminopeptidase N from the midgut epithelium of Manduca sexta that binds Cry1Ab5, an insecticidal crystal protein [ICP] from Bacillus thuringiensis. Sequence information derived from this M. sexta aminopeptidase N was used for the cloning of an aminopeptidase N from the midgut brush-border membrane of Plutella xylostella, an insect species of which some populations acquired resistance against Cry1Ab5. Affinity chromatography on a Cry1Ab5 matrix was used to isolate a 120-kDa glycoprotein from the larval midgut of the lepidopteran M. sexta. On ligand blots the purified 120-kDa protein discriminates between the lepidopteran-specific Cry1Ab5 and the coleopteran-specific Cry3A delta-endotoxin. Internal amino acid sequences from the 120-kDa protein were used for the design of degenerate oligonucleotides. From a nested PCR with M. sexta midgut cDNA as template, a DNA fragment was obtained which shows similarity to prokaryotic and eukaryotic aminopeptidase N genes. This PCR fragment was used to screen cDNA libraries of larval midguts from M. sexta and P. xylostella. From the M. sexta midgut cDNA library a 2973-bp nucleotide sequence was cloned. The ORF of the sequence encodes a 942-residue aminopeptidase N (M. sexta Apn2) containing two hydrophobic regions. The NH2-terminal hydrophobic region corresponds to a secretory signal sequence and the COOH-terminal hydrophobic region is typical of glycosylphosphatidylinositol (glycosyl-PtdIns)-anchored proteins. Low-stringency hybridization of the P. xylostella midgut cDNA library with M. sexta apn2 probes enabled the isolation of a 3118-bp sequence with an ORF encoding a 946-residue preproprotein. This aminopeptidase N (P. xylostella Apn1) displays 61% amino acid identity to M. sexta Apn2 and contains a COOH-terminal signal peptide for glycosyl-PtdIns anchor addition. Both M. sexta Apn2 and P. xylostella Apn1 contain four Cys residues, which are highly conserved among

  11. Rosmarinic acid, a new snake venom phospholipase A2 inhibitor from Cordia verbenacea (Boraginaceae): antiserum action potentiation and molecular interaction.

    Science.gov (United States)

    Ticli, Fábio K; Hage, Lorane I S; Cambraia, Rafael S; Pereira, Paulo S; Magro, Angelo J; Fontes, Marcos R M; Stábeli, Rodrigo G; Giglio, José R; França, Suzelei C; Soares, Andreimar M; Sampaio, Suely V

    2005-09-01

    Many plants are used in traditional medicine as active agents against various effects induced by snakebite. The methanolic extract from Cordia verbenacea (Cv) significantly inhibited paw edema induced by Bothrops jararacussu snake venom and by its main basic phospholipase A2 homologs, namely bothropstoxins I and II (BthTXs). The active component was isolated by chromatography on Sephadex LH-20 and by RP-HPLC on a C18 column and identified as rosmarinic acid (Cv-RA). Rosmarinic acid is an ester of caffeic acid and 3,4-dihydroxyphenyllactic acid [2-O-cafeoil-3-(3,4-di-hydroxy-phenyl)-R-lactic acid]. This is the first report of RA in the species C. verbenacea ('baleeira', 'whaler') and of its anti-inflammatory and antimyotoxic properties against snake venoms and isolated toxins. RA inhibited the edema and myotoxic activity induced by the basic PLA2s BthTX-I and BthTX-II. It was, however, less efficient to inhibit the PLA2 activity of BthTX-II and, still less, the PLA2 and edema-inducing activities of the acidic isoform BthA-I-PLA2 from the same venom, showing therefore a higher inhibitory activity upon basic PLA2s. RA also inhibited most of the myotoxic and partially the edema-inducing effects of both basic PLA2s, thus reinforcing the idea of dissociation between the catalytic and pharmacological domains. The pure compound potentiated the ability of the commercial equine polyvalent antivenom in neutralizing lethal and myotoxic effects of the crude venom and of isolated PLA2s in experimental models. CD data presented here suggest that, after binding, no significant conformation changes occur either in the Cv-RA or in the target PLA2. A possible model for the interaction of rosmarinic acid with Lys49-PLA2 BthTX-I is proposed.

  12. Atractaspis aterrima Toxins: The First Insight into the Molecular Evolution of Venom in Side-Stabbers

    Science.gov (United States)

    Terrat, Yves; Sunagar, Kartik; Fry, Bryan G.; Jackson, Timothy N. W.; Scheib, Holger; Fourmy, Rudy; Verdenaud, Marion; Blanchet, Guillaume; Antunes, Agostinho; Ducancel, Frederic

    2013-01-01

    Although snake venoms have been the subject of intense research, primarily because of their tremendous potential as a bioresource for design and development of therapeutic compounds, some specific groups of snakes, such as the genus Atractaspis, have been completely neglected. To date only limited number of toxins, such as sarafotoxins have been well characterized from this lineage. In order to investigate the molecular diversity of venom from Atractaspis aterrima—the slender burrowing asp, we utilized a high-throughput transcriptomic approach completed with an original bioinformatics analysis pipeline. Surprisingly, we found that Sarafotoxins do not constitute the major ingredient of the transcriptomic cocktail; rather a large number of previously well-characterized snake venom-components were identified. Notably, we recovered a large diversity of three-finger toxins (3FTxs), which were found to have evolved under the significant influence of positive selection. From the normalized and non-normalized transcriptome libraries, we were able to evaluate the relative abundance of the different toxin groups, uncover rare transcripts, and gain new insight into the transcriptomic machinery. In addition to previously characterized toxin families, we were able to detect numerous highly-transcribed compounds that possess all the key features of venom-components and may constitute new classes of toxins. PMID:24169588

  13. Shiga toxin induces membrane reorganization and formation of long range lipid order

    DEFF Research Database (Denmark)

    Solovyeva, Vita; Johannes, Ludger; Simonsen, Adam Cohen

    2015-01-01

    microscopy. A content of 1% of glycosphingolipid globotriaosylceramide (Gb3) receptor lipids in a bilayer was used to bind the Shiga toxin B-subunit to the surface of gel domains. Binding of the Shiga toxin B-subunit to lipids led to the modulation of orientational membrane texture in gel domains and induced...... membrane reordering. When Shiga toxin was added above the lipid chain melting temperature, the toxin interaction with the membrane induced rearrangement and clustering of Gb3 lipids that resulted in the long range order and alignment of lipids in gel domains. The toxin induced redistribution of Gb3 lipids...

  14. snake and staff symbolism and healing 1. introduction 2. the snake ...

    African Journals Online (AJOL)

    Since time immemorial the snake has been venerated as an enigmatic creature with supernatural powers. As a snake and staff symbol it is also traditionally associated with the healing arts, either as the single-snake attribute of Asclepius, or as the double- snake attribute of Hermes. In this article the mythological basis for ...

  15. Cobra venom proteome and glycome determined from individual snakes of Naja atra reveal medically important dynamic range and systematic geographic variation.

    Science.gov (United States)

    Huang, Hsuan-Wei; Liu, Bing-Sin; Chien, Kun-Yi; Chiang, Liao-Chun; Huang, Sheng-Yu; Sung, Wang-Chou; Wu, Wen-Guey

    2015-10-14

    Recent progress in snake venomics has shed much light on the intra-species variation among the toxins from different geographical regions and has provided important information for better snakebite management. Most previous reports on snake venomics were based on venoms pooled from different snakes. In this study, we present the proteomic and glycomic profiles of venoms from individual Naja atra snakes. The results reveal wide dynamic range of three-finger toxins. Systematic classification based on cardiotoxin (CTX-) profiles of A2/A4 and A6, respectively, allowed the identification of two putative subspecies of Taiwan cobra from the eastern and western regions. We also identified four major N-glycan moieties on cobra snake venom metalloproteinase on the bi-antennary glycan core. ELISA showed that these glycoproteins (cobra venom toxins such as small molecular weight CTXs (~60%). By removing these high-molecular weight glycoproteins from the immunogen, we demonstrated better protection than that achieved with conventional crude venom immunization in mice challenged by crude venom. We conclude that both intra-species and inter-individual variations of proteomic and glycomic profiles of snake venomics should be considered to provide better antivenomic approach for snakebite management. Based on the proteomic and glycomic profiles of venoms obtained from individual snakes, we demonstrated a surprisingly wide dynamic range and geographical variation of three-finger toxins in cobra venomics. This provides a reasonable explanation for the variable neutralization effects of antivenom treatment on victims suffering from cobra snakebite and suggests a simple and economic method to produce potent antivenom with better efficacy. Since two major venomic profiles with distinct dynamic ranges were observed for Taiwan cobra venoms isolated from the eastern and western regions, the current venomic profile should be used as a quality control for future production of antivenom in

  16. Plasma concentrations of chloramphenicol in snakes.

    Science.gov (United States)

    Clark, C H; Rogers, E D; Milton, J L

    1985-12-01

    Plasma chloramphenicol concentrations after a subcutaneous injection were studied in 87 snakes of 16 different species. The biological half-life of chloramphenicol varied from 3.3 hours in the indigo snake (Drymarchon corais couperi) to 22.1 hours in the midland water snake (Nerodia sipedon). A single dosage of 50 mg of chloramphenicol/kg of body weight produced plasma concentrations greater than 5 micrograms/ml for nearly 72 hours in 2 species of water snakes (Nerodia erythrogaster, Nerodia sipedon), for 24 hours in the Burmese python (Python molurus bivittatus), and for less than 12 hours in the gray rat snake, Indigo snake, and eastern king snake (Elaphe obsoleta spiloides, Drymarchon coraise couperi, and Lampropeltis getulus getulus). A dosage of 50 mg/kg administered to water snakes every 72 hours for 18 days maintained a minimum plasma concentration of chloramphenicol between 2 and 5 micrograms/ml.

  17. Computational Studies of Marine Toxins Targeting Ion Channels

    Directory of Open Access Journals (Sweden)

    Serdar Kuyucak

    2013-03-01

    Full Text Available Toxins from marine animals offer novel drug leads for treatment of diseases involving ion channels. Computational methods could be very helpful in this endeavour in several ways, e.g., (i constructing accurate models of the channel-toxin complexes using docking and molecular dynamics (MD simulations; (ii determining the binding free energies of toxins from umbrella sampling MD simulations; (iii predicting the effect of mutations from free energy MD simulations. Using these methods, one can design new analogs of toxins with improved affinity and selectivity properties. Here we present a review of the computational methods and discuss their applications to marine toxins targeting potassium and sodium channels. Detailed examples from the potassium channel toxins—ShK from sea anemone and κ-conotoxin PVIIA—are provided to demonstrate capabilities of the computational methods to give accurate descriptions of the channel-toxin complexes and the energetics of their binding. An example is also given from sodium channel toxins (μ-conotoxin GIIIA to illustrate the differences between the toxin binding modes in potassium and sodium channels.

  18. The oldest known snakes from the Middle Jurassic-Lower Cretaceous provide insights on snake evolution.

    Science.gov (United States)

    Caldwell, Michael W; Nydam, Randall L; Palci, Alessandro; Apesteguía, Sebastián

    2015-01-27

    The previous oldest known fossil snakes date from ~100 million year old sediments (Upper Cretaceous) and are both morphologically and phylogenetically diverse, indicating that snakes underwent a much earlier origin and adaptive radiation. We report here on snake fossils that extend the record backwards in time by an additional ~70 million years (Middle Jurassic-Lower Cretaceous). These ancient snakes share features with fossil and modern snakes (for example, recurved teeth with labial and lingual carinae, long toothed suborbital ramus of maxillae) and with lizards (for example, pronounced subdental shelf/gutter). The paleobiogeography of these early snakes is diverse and complex, suggesting that snakes had undergone habitat differentiation and geographic radiation by the mid-Jurassic. Phylogenetic analysis of squamates recovers these early snakes in a basal polytomy with other fossil and modern snakes, where Najash rionegrina is sister to this clade. Ingroup analysis finds them in a basal position to all other snakes including Najash.

  19. Biodiscovery of Aluminum Binding Peptides

    Science.gov (United States)

    2013-08-01

    conjunction with organic-based targets, such as protein toxins or carbon nanotubes . However, this technology has been expanded for use with inorganic...conjunction with organic-based targets, such as protein toxins or carbon nanotubes . However, this technology has been expanded for use with inorganic targets...8] Rothenstein, D. C., et al., "Isolation of ZnO -binding 12-mer peptides and determination of their binding epitopes by NMR spectroscopy," J. Am

  20. Inhibition of cholera toxin by human milk fractions and sialyllactose.

    Science.gov (United States)

    Idota, T; Kawakami, H; Murakami, Y; Sugawara, M

    1995-03-01

    The effects of human milk fractions on clolera toxin B subunit binding to monosialoganglioside 1 (GM1) were investigated. Human milk, human defatted milk, whey, and a low-molecular-weight fraction of human milk inhibited the binding, but casein did not inhibit it. The inhibitory activity of whey from bovine-milk-based infant formula was less than that of whey from human milk. Differences in composition between human and bovine whey seemed to influence the extent of the inhibitory activity. Sialylated oligosaccharides were considered to be the possible components that inhibited cholera toxin. The effects of sialyllactose, a predominant sialylated component of human milk, on cholera toxin-induced diarrhea were investigated by the rabbit intestinal loop method. Sialyllactose inhibited the cholera toxin inducing fluid accumulation, although neither sialic acid nor lactose had an effect on it. The results suggest that sialyllactose is responsible for the inhibitory activity of milk on cholera toxin.

  1. Expression of venom gene homologs in diverse python tissues suggests a new model for the evolution of snake venom.

    Science.gov (United States)

    Reyes-Velasco, Jacobo; Card, Daren C; Andrew, Audra L; Shaney, Kyle J; Adams, Richard H; Schield, Drew R; Casewell, Nicholas R; Mackessy, Stephen P; Castoe, Todd A

    2015-01-01

    Snake venom gene evolution has been studied intensively over the past several decades, yet most previous studies have lacked the context of complete snake genomes and the full context of gene expression across diverse snake tissues. We took a novel approach to studying snake venom evolution by leveraging the complete genome of the Burmese python, including information from tissue-specific patterns of gene expression. We identified the orthologs of snake venom genes in the python genome, and conducted detailed analysis of gene expression of these venom homologs to identify patterns that differ between snake venom gene families and all other genes. We found that venom gene homologs in the python are expressed in many different tissues outside of oral glands, which illustrates the pitfalls of using transcriptomic data alone to define "venom toxins." We hypothesize that the python may represent an ancestral state prior to major venom development, which is supported by our finding that the expansion of venom gene families is largely restricted to highly venomous caenophidian snakes. Therefore, the python provides insight into biases in which genes were recruited for snake venom systems. Python venom homologs are generally expressed at lower levels, have higher variance among tissues, and are expressed in fewer organs compared with all other python genes. We propose a model for the evolution of snake venoms in which venom genes are recruited preferentially from genes with particular expression profile characteristics, which facilitate a nearly neutral transition toward specialized venom system expression. © The Author 2014. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  2. Unveiling the elusive and exotic: Venomics of the Malayan blue coral snake (Calliophis bivirgata flaviceps).

    Science.gov (United States)

    Tan, Choo Hock; Fung, Shin Yee; Yap, Michelle Khai Khun; Leong, Poh Kuan; Liew, Jia Lee; Tan, Nget Hong

    2016-01-30

    The venom proteome of the Malayan blue coral snake, Calliophis bivirgata flaviceps from west Malaysia was investigated by 1D-SDS-PAGE and shotgun-LCMS/MS. A total of 23 proteins belonging to 11 protein families were detected from the venom proteome. For the toxin proteins, the venom consists mainly of phospholipase A2 (41.1%), cytotoxin (22.6%), SVMPs (18.7%) and vespryns (14.6%). However, in contrast to the venoms of New World coral snakes and most elapids, there was no post-synaptic α-neurotoxin detected. The proteome also revealed a relatively high level of phosphodiesterase (1.3%), which may be associated with the reported high level of adenosine in the venom. Also detected were 5'-nucleotidase (0.3%), hyaluronidase (0.1%) and cysteine-type endopeptide inhibitor (0.6%). Enzymatic studies confirmed the presence of phospholipase A2, phosphodiesterase, 5'-nucleotidase and acetylcholinesterase activities but not l-amino acid oxidase activity. The venom exhibited moderate cytotoxic activity against CRL-2648 fibroblast cell lines (IC50=62.14±0.87 μg/mL) and myotoxicity in mice, presumably due to the action of its cytotoxin or its synergistic action with phospholipase A2. Interestingly, the venom lethality could be cross-neutralized by a neurotoxic bivalent antivenom from Taiwan. Together, the findings provide insights into the composition and functions of the venom of this exotic oriental elapid snake. While venoms of the New World coral snake have been extensively studied, literature pertaining to the Old World or Asiatic coral snake venoms remains lacking. This could be partly due to the inaccessibility to the venom of this rare species and infrequent cases of envenomation reported. This study identified and profiled the venom proteome of the Malayan blue coral snake (C. b. flaviceps) through SDS-PAGE and a high-resolution nano-LCMS/MS method, detailing the types and abundance of proteins found in the venom. The biological and toxic activities of the venom were

  3. 33 CFR 117.331 - Snake Creek.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Snake Creek. 117.331 Section 117.331 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Florida § 117.331 Snake Creek. The draw of the Snake Creek...

  4. 33 CFR 117.1058 - Snake River.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Snake River. 117.1058 Section 117... OPERATION REGULATIONS Specific Requirements Washington § 117.1058 Snake River. (a) The draw of the Burlington Northern Santa Fe railroad bridge across the Snake River at mile 1.5 between Pasco and Burbank is...

  5. Coyotes Are Afraid of Little Snakes.

    Science.gov (United States)

    Weewish Tree, 1979

    1979-01-01

    Wichita tale of a contest between Coyote and Small Snake to see whose teeth are strongest. They bite each other, and soon big, strong Coyote is dead from the poisoned bite of the tiny snake. Explains why, from that time onward, coyotes have been afraid of little snakes. (DS)

  6. Design of a new therapy to treat snake envenomation

    Directory of Open Access Journals (Sweden)

    Shahidi Bonjar L

    2014-06-01

    become immobilized, and are eliminated from the poisoned patient blood. Detoxification resuscitation is expected to take 2–3 hours, when the titers of venom antigens in the blood reach harmless levels, as confirmed by sampling of the blood and appropriate serological evaluations. If conventional antivenoms do not cover the entire spectrum of venom antigens in blood, rehabilitation would be a matter of a longer period; whilst the PVAC covers the widest range of antibodies to remove the broadest range of venom antigens, the rehabilitation period would be shorter since venom antigens have been removed from the body in a few hours duration. PVACs are to be biotechnologically engineered against a wide spectra of antigens present in the venoms of the dominant poisonous snakes for a defined geographical zone; ie, a country, part of a continent, or an entire continent. As a polyvalent column, the PVAC bears a sufficient amount of venom antibodies of all snakes that pose a threat in the region. PVAC treatment would have high applicability in cases where the patient is unconscious and/or the snake identity is not clear for administration of related antivenom medication. For opportune administration, research on the use of PVACs in emergency ambulances should receive special attention. Starting in situ detoxification, such ambulances would provide more efficient resuscitations to envenomed patients.Keywords: venom, toxin, intoxication, detoxification, blood, polyvalent antibody

  7. Molecular Identification of Cryptosporidium Species from Pet Snakes in Thailand

    OpenAIRE

    Yimming, Benjarat; Pattanatanang, Khampee; SANYATHITISEREE, PORNCHAI; Inpankaew, Tawin; KAMYINGKIRD, Ketsarin; Pinyopanuwat, Nongnuch; Chimnoi, Wissanuwat; Phasuk, Jumnongjit

    2016-01-01

    Cryptosporidium is an important pathogen causing gastrointestinal disease in snakes and is distributed worldwide. The main objectives of this study were to detect and identify Cryptosporidium species in captive snakes from exotic pet shops and snake farms in Thailand. In total, 165 fecal samples were examined from 8 snake species, boa constrictor (Boa constrictor constrictor), corn snake (Elaphe guttata), ball python (Python regius), milk snake (Lampropeltis triangulum), king snake (Lampropel...

  8. A New Platelet-Aggregation-Inhibiting Factor Isolated from Bothrops moojeni Snake Venom

    Directory of Open Access Journals (Sweden)

    Bruna Barbosa de Sousa

    2017-01-01

    Full Text Available This work reports the purification and functional characterization of BmooPAi, a platelet-aggregation-inhibiting factor from Bothrops moojeni snake venom. The toxin was purified by a combination of three chromatographic steps (ion-exchange on DEAE-Sephacel, molecular exclusion on Sephadex G-75, and affinity chromatography on HiTrap™ Heparin HP. BmooPAi was found to be a single-chain protein with an apparent molecular mass of 32 kDa on 14% SDS-PAGE, under reducing conditions. Sequencing of BmooPAi by Edman degradation revealed the amino acid sequence LGPDIVPPNELLEVM. The toxin was devoid of proteolytic, haemorrhagic, defibrinating, or coagulant activities and induced no significant oedema or hyperalgesia. BmooPAi showed a rather specific inhibitory effect on ristocetin-induced platelet aggregation in human platelet-rich plasma, whereas it had little or no effect on platelet aggregation induced by collagen and adenosine diphosphate. The results presented in this work suggest that BmooPAi is a toxin comprised of disintegrin-like and cysteine-rich domains, originating from autolysis/proteolysis of PIII SVMPs from B. moojeni snake venom. This toxin may be of medical interest because it is a platelet aggregation inhibitor, which could potentially be developed as a novel therapeutic agent to prevent and/or treat patients with thrombotic disorders.

  9. Toxin studies using an integrated biophysical and structural biology approach.

    Energy Technology Data Exchange (ETDEWEB)

    Last, Julie A.; Schroeder, Anne E.; Slade, Andrea Lynn; Sasaki, Darryl Yoshio; Yip, Christopher M. (University of Toronto, Toronto, Ontario, Canada); Schoeniger, Joseph S. (Sandia National Laboratories, Livermore, CA)

    2005-03-01

    Clostridial neurotoxins, such as botulinum and tetanus, are generally thought to invade neural cells through a process of high affinity binding mediated by gangliosides, internalization via endosome formation, and subsequent membrane penetration of the catalytic domain activated by a pH drop in the endosome. This surface recognition and internalization process is still not well understood with regard to what specific membrane features the toxins target, the intermolecular interactions between bound toxins, and the molecular conformational changes that occur as a result of pH lowering. In an effort to elucidate the mechanism of tetanus toxin binding and permeation through the membrane a simple yet representative model was developed that consisted of the ganglioside G{sub tlb} incorporated in a bilayer of cholesterol and DPPC (dipalmitoylphosphatidyl choline). The bilayers were stable over time yet sensitive towards the binding and activity of whole toxin. A liposome leakage study at constant pH as well as with a pH gradient, to mimic the processes of the endosome, was used to elucidate the effect of pH on the toxin's membrane binding and permeation capability. Topographic imaging of the membrane surface, via in situ tapping mode AFM, provided nanoscale characterization of the toxin's binding location and pore formation activity.

  10. Snake fungal disease: An emerging threat to wild snakes

    Science.gov (United States)

    Lorch, Jeffrey M.; Knowles, Susan N.; Lankton, Julia S.; Michell, Kathy; Edwards, Jaime L.; Kapfer, Joshua M.; Staffen, Richard A.; Wild, Erik R.; Schmidt, Katie Z.; Ballmann, Anne; Blodgett, Doug; Farrell, Terence M.; Glorioso, Brad M.; Last, Lisa A.; Price, Steven J.; Schuler, Krysten L.; Smith, Christopher E.; Wellehan, James F. X.; Blehert, David S.

    2016-01-01

    Since 2006, there has been a marked increase in the number of reports of severe and often fatal fungal skin infections in wild snakes in the eastern USA. The emerging condition, referred to as snake fungal disease (SFD), was initially documented in rattlesnakes, where the infections were believed to pose a risk to the viability of affected populations. The disease is caused byOphidiomyces ophiodiicola, a fungus recently split from a complex of fungi long referred to as the Chrysosporium anamorph of Nannizziopsis vriesii (CANV). Here we review the current state of knowledge about O. ophiodiicola and SFD. In addition, we provide original findings which demonstrate that O. ophiodiicola is widely distributed in eastern North America, has a broad host range, is the predominant cause of fungal skin infections in wild snakes and often causes mild infections in snakes emerging from hibernation. This new information, together with what is already available in the scientific literature, advances our knowledge of the cause, pathogenesis and ecology of SFD. However, additional research is necessary to elucidate the factors driving the emergence of this disease and develop strategies to mitigate its impacts.

  11. Snake fungal disease: an emerging threat to wild snakes.

    Science.gov (United States)

    Lorch, Jeffrey M; Knowles, Susan; Lankton, Julia S; Michell, Kathy; Edwards, Jaime L; Kapfer, Joshua M; Staffen, Richard A; Wild, Erik R; Schmidt, Katie Z; Ballmann, Anne E; Blodgett, Doug; Farrell, Terence M; Glorioso, Brad M; Last, Lisa A; Price, Steven J; Schuler, Krysten L; Smith, Christopher E; Wellehan, James F X; Blehert, David S

    2016-12-05

    Since 2006, there has been a marked increase in the number of reports of severe and often fatal fungal skin infections in wild snakes in the eastern USA. The emerging condition, referred to as snake fungal disease (SFD), was initially documented in rattlesnakes, where the infections were believed to pose a risk to the viability of affected populations. The disease is caused by Ophidiomyces ophiodiicola, a fungus recently split from a complex of fungi long referred to as the Chrysosporium anamorph of Nannizziopsis vriesii (CANV). Here we review the current state of knowledge about O. ophiodiicola and SFD. In addition, we provide original findings which demonstrate that O. ophiodiicola is widely distributed in eastern North America, has a broad host range, is the predominant cause of fungal skin infections in wild snakes and often causes mild infections in snakes emerging from hibernation. This new information, together with what is already available in the scientific literature, advances our knowledge of the cause, pathogenesis and ecology of SFD. However, additional research is necessary to elucidate the factors driving the emergence of this disease and develop strategies to mitigate its impacts.This article is part of the themed issue 'Tackling emerging fungal threats to animal health, food security and ecosystem resilience'. © 2016 The Author(s).

  12. [Hemolysis of Scolopendra toxins].

    Science.gov (United States)

    Deng, F; Fang, H; Wang, K

    1997-01-01

    The hemolysis of toxins from alive Scolopendra subspinipes mutilans, medicinal material of Scolopendra subspimipes mutilans and S. multidens have been compared. The result shows that all the toxins have hemolytic activity. The hemolytic activity of the toxin from the medicinal materials of S. subspinipes mutilans is obviously lower than that from alive ones, and that from fresh medicinal materials are twice as high that from old ones, and that from S. multidens is higher than that from S. subspinipes multilans.

  13. Snake Robots Modelling, Mechatronics, and Control

    CERN Document Server

    Liljebäck, Pål; Stavdahl, Øyvind; Gravdahl, Jan Tommy

    2013-01-01

    Snake Robots is a novel treatment of theoretical and practical topics related to snake robots: robotic mechanisms designed to move like biological snakes and able to operate in challenging environments in which human presence is either undesirable or impossible. Future applications of such robots include search and rescue, inspection and maintenance, and subsea operations. Locomotion in unstructured environments is a focus for this book. The text targets the disparate muddle of approaches to modelling, development and control of snake robots in current literature, giving a unified presentation of recent research results on snake robot locomotion to increase the reader’s basic understanding of these mechanisms and their motion dynamics and clarify the state of the art in the field. The book is a complete treatment of snake robotics, with topics ranging from mathematical modelling techniques, through mechatronic design and implementation, to control design strategies. The development of two snake robots is de...

  14. A description of parasites from Iranian snakes.

    Science.gov (United States)

    Nasiri, Vahid; Mobedi, Iraj; Dalimi, Abdolhossein; Mirakabadi, Abbas Zare; Ghaffarifar, Fatemeh; Teymurzadeh, Shohreh; Karimi, Gholamreza; Abdoli, Amir; Paykari, Habibollah

    2014-12-01

    Little is known of the parasitic fauna of terrestrial snakes in Iran. This study aimed to evaluate the parasitic infection rates of snakes in Iran. A total of 87 snakes belonging to eight different species, that were collected between May 2012 and September 2012 and died after the hold in captivity, under which they were kept for taking poisons, were examined for the presence of gastrointestinal and blood parasites. According to our study 12 different genera of endoparasites in 64 (73.56%) of 87 examined snakes were determined. Forty one snakes (47.12%) had gastrointestinal parasites. In prepared blood smears, it was found that in 23 (26.43%) of 87 examined snakes there are at least one hemoparasite. To our knowledge, these are the first data on the internal parasitic fauna of Iranian terrestrial snakes and our findings show a higher prevalence of these organisms among them. Copyright © 2014 Elsevier Inc. All rights reserved.

  15. Crystallization and preliminary X-ray analysis of coagulation factor IX-binding protein from habu snake venom at pH 6.5 and 4.6

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Nobuhiro [Institute of Applied Biochemistry, University of Tsukuba, Tsukuba, Ibaraki 305-8572 (Japan); Department of Biochemisty, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki 305-8602 (Japan); Shikamoto, Yasuo; Fujimoto, Zui [Department of Biochemisty, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki 305-8602 (Japan); Morita, Takashi [Department of Biochemistry, Meiji Pharmaceutical University, Kiyose, Tokyo 204-8588 (Japan); Mizuno, Hiroshi, E-mail: mizuno@affrc.go.jp [Department of Biochemisty, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki 305-8602 (Japan); Institute of Applied Biochemistry, University of Tsukuba, Tsukuba, Ibaraki 305-8572 (Japan)

    2005-01-01

    Crystals of habu coagulation factor IX-binding protein have been obtained at pH 6.5 and 4.6 and characterized by X-ray diffraction. Coagulation factor IX-binding protein isolated from Trimeresurus flavoviridis (IX-bp) is a C-type lectin-like protein. It is an anticoagulant protein consisting of homologous subunits A and B. The subunits both contain a Ca{sup 2+}-binding site with differing affinity (K{sub d} values of 14 and 130 µM at pH 7.5). These binding characteristics are pH-dependent; under acidic conditions, the affinity of the low-affinity site was reduced considerably. In order to identify which site has high affinity and also to investigate the Ca{sup 2+}-releasing mechanism, IX-bp was crystallized at pH 6.5 and 4.6. The crystals at pH 6.5 and 4.6 diffracted to 1.72 and 2.29 Å resolution, respectively; the former crystals belong to the monoclinic space group P2{sub 1}, with unit-cell parameters a = 60.7, b = 63.5, c = 66.9 Å, β = 117.0°, while the latter belong to the monoclinic space group C2, with a = 134.1, b = 37.8, c = 55.8 Å, β = 110.4°.

  16. Synthetic peptides derived from the C-terminal region of Lys49 phospholipase A2 homologues from viperidae snake venoms: biomimetic activities and potential applications.

    Science.gov (United States)

    Lomonte, Bruno; Angulo, Yamileth; Moreno, Edgardo

    2010-01-01

    Lys49-phospholipase A(2) homologues constitute a large family of toxins present in the venoms of viperid snake species, which despite lacking catalytic activity, cause significant skeletal muscle necrosis. The main structural determinants of this toxic effect have been experimentally mapped to a region near their C-terminus (115-129), which combines cationic and hydrophobic/aromatic amino acid residues. Short (13-mer) synthetic peptides representing this C-terminal region can mimick several of the effects of Lys49 PLA(2) homologues. In addition to their ability to damage muscle cells, these peptides display antibacterial, antiendotoxic, antifungal, antiparasite, and antitumor activities, as well as VEGF-receptor 2 (KDR)-binding and heparin-binding properties. Modifications of their sequences have shown possibilities to enhance their effects upon prokaryotic cells, while decreasing toxicity for eukaryotic cells. This review presents an updated summary on the biomimetic actions exerted by such peptides, and highlights their potential value as molecular tools or as drug leads in diverse biomedical areas.

  17. Oligomerization of Clostridium perfringens epsilon toxin is dependent upon caveolins 1 and 2.

    Directory of Open Access Journals (Sweden)

    Christine M Fennessey

    Full Text Available Evidence from multiple studies suggests that Clostridium perfringens ε-toxin is a pore-forming toxin, assembling into oligomeric complexes in the plasma membrane of sensitive cells. In a previous study, we used gene-trap mutagenesis to identify mammalian factors contributing to toxin activity, including caveolin-2 (CAV2. In this study, we demonstrate the importance of caveolin-2 and its interaction partner, caveolin-1 (CAV1, in ε-toxin-induced cytotoxicity. Using CAV2-specific shRNA in a toxin-sensitive human kidney cell line, ACHN, we confirmed that cells deficient in CAV2 exhibit increased resistance to ε-toxin. Similarly, using CAV1-specific shRNA, we demonstrate that cells deficient in CAV1 also exhibit increased resistance to the toxin. Immunoprecipitation of CAV1 and CAV2 from ε-toxin-treated ACHN cells demonstrated interaction of both CAV1 and -2 with the toxin. Furthermore, blue-native PAGE indicated that the toxin and caveolins were components of a 670 kDa protein complex. Although ε-toxin binding was only slightly perturbed in caveolin-deficient cells, oligomerization of the toxin was dramatically reduced in both CAV1- and CAV2-deficient cells. These results indicate that CAV1 and -2 potentiate ε-toxin induced cytotoxicity by promoting toxin oligomerization - an event which is requisite for pore formation and, by extension, cell death.

  18. The ether lipid precursor hexadecylglycerol protects against Shiga toxins.

    Science.gov (United States)

    Bergan, Jonas; Skotland, Tore; Lingelem, Anne Berit Dyve; Simm, Roger; Spilsberg, Bjørn; Lindbäck, Toril; Sylvänne, Tuulia; Simolin, Helena; Ekroos, Kim; Sandvig, Kirsten

    2014-11-01

    Shiga toxin-producing Escherichia coli bacteria cause hemorrhagic colitis and hemolytic uremic syndrome in humans. Currently, only supportive treatment is available for diagnosed patients. We show here that 24-h pretreatment with an ether lipid precursor, the alkylglycerol sn-1-O-hexadecylglycerol (HG), protects HEp-2 cells against Shiga toxin and Shiga toxin 2. Also the endothelial cell lines HMEC-1 and HBMEC are protected against Shiga toxins after HG pretreatment. In contrast, the corresponding acylglycerol, DL-α-palmitin, has no effect on Shiga toxicity. Although HG treatment provides a strong protection (~30 times higher IC₅₀) against Shiga toxin, only a moderate reduction in toxin binding was observed, suggesting that retrograde transport of the toxin from the plasma membrane to the cytosol is perturbed. Furthermore, endocytosis of Shiga toxin and retrograde sorting from endosomes to the Golgi apparatus remain intact, but transport from the Golgi to the endoplasmic reticulum is inhibited by HG treatment. As previously described, HG reduces the total level of all quantified glycosphingolipids to 50-70% of control, including the Shiga toxin receptor globotriaosylceramide (Gb3), in HEp-2 cells. In accordance with this, we find that interfering with Gb3 biosynthesis by siRNA-mediated knockdown of Gb3 synthase for 24 h causes a similar cytotoxic protection and only a moderate reduction in toxin binding (to 70% of control cells). Alkylglycerols, including HG, have been administered to humans for investigation of therapeutic roles in disorders where ether lipid biosynthesis is deficient, as well as in cancer therapy. Further studies may reveal if HG can also have a therapeutic potential in Shiga toxin-producing E. coli infections.

  19. Toxin-Induced Experimental Models of Learning and Memory Impairment.

    Science.gov (United States)

    More, Sandeep Vasant; Kumar, Hemant; Cho, Duk-Yeon; Yun, Yo-Sep; Choi, Dong-Kug

    2016-09-01

    Animal models for learning and memory have significantly contributed to novel strategies for drug development and hence are an imperative part in the assessment of therapeutics. Learning and memory involve different stages including acquisition, consolidation, and retrieval and each stage can be characterized using specific toxin. Recent studies have postulated the molecular basis of these processes and have also demonstrated many signaling molecules that are involved in several stages of memory. Most insights into learning and memory impairment and to develop a novel compound stems from the investigations performed in experimental models, especially those produced by neurotoxins models. Several toxins have been utilized based on their mechanism of action for learning and memory impairment such as scopolamine, streptozotocin, quinolinic acid, and domoic acid. Further, some toxins like 6-hydroxy dopamine (6-OHDA), 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and amyloid-β are known to cause specific learning and memory impairment which imitate the disease pathology of Parkinson's disease dementia and Alzheimer's disease dementia. Apart from these toxins, several other toxins come under a miscellaneous category like an environmental pollutant, snake venoms, botulinum, and lipopolysaccharide. This review will focus on the various classes of neurotoxin models for learning and memory impairment with their specific mechanism of action that could assist the process of drug discovery and development for dementia and cognitive disorders.

  20. Toxin-Induced Experimental Models of Learning and Memory Impairment

    Directory of Open Access Journals (Sweden)

    Sandeep Vasant More

    2016-09-01

    Full Text Available Animal models for learning and memory have significantly contributed to novel strategies for drug development and hence are an imperative part in the assessment of therapeutics. Learning and memory involve different stages including acquisition, consolidation, and retrieval and each stage can be characterized using specific toxin. Recent studies have postulated the molecular basis of these processes and have also demonstrated many signaling molecules that are involved in several stages of memory. Most insights into learning and memory impairment and to develop a novel compound stems from the investigations performed in experimental models, especially those produced by neurotoxins models. Several toxins have been utilized based on their mechanism of action for learning and memory impairment such as scopolamine, streptozotocin, quinolinic acid, and domoic acid. Further, some toxins like 6-hydroxy dopamine (6-OHDA, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP and amyloid-β are known to cause specific learning and memory impairment which imitate the disease pathology of Parkinson’s disease dementia and Alzheimer’s disease dementia. Apart from these toxins, several other toxins come under a miscellaneous category like an environmental pollutant, snake venoms, botulinum, and lipopolysaccharide. This review will focus on the various classes of neurotoxin models for learning and memory impairment with their specific mechanism of action that could assist the process of drug discovery and development for dementia and cognitive disorders.

  1. Venomous Snake Bite Injuries at Kitui District Hospital | Kihiko ...

    African Journals Online (AJOL)

    Background Snake bites are a neglected public health issue in poor rural communities, and the true burden of snake bites is not known. Kitui County has a high incidence of snake bites and no functional snake bite control programs exists. Diagnostic tests for snake species identification are not available and management ...

  2. Proteomic profiling of liver from Elaphe taeniura, a common snake in eastern and southeastern Asia

    Directory of Open Access Journals (Sweden)

    Liang Chen

    2013-01-01

    Full Text Available Snake liver has been implicated in the adaptation of snakes to a variety of habitats. However, to date, there has been no systematic analysis of snake liver proteins. In this study, we undertook a proteomic analysis of liver from the colubrid snake Elaphe taeniura using a combination of two-dimensional electrophoresis (2-DE and matrix-assisted laser desorption/ionization time of flightmass spectrometry (MALDI-TOF MS. We also constructed a local protein sequence database based on transcriptome sequencing to facilitate protein identification. Of the 268 protein spots revealed by 2-DE 109 gave positive MS signals, 84 of which were identified by searching the NCBInr, Swiss-Prot and local databases. The other 25 protein spots could not be identified, possibly because their transcripts were not be stable enough to be detected by transcriptome sequencing. GO analysis showed that most proteins may be involved in binding, catalysis, cellular processes and metabolic processes. Forty-two of the liver proteins identified were found in other reptiles and in amphibians. The findings of this study provide a good reference map of snake liver proteins that will be useful in molecular investigations of snake physiology and adaptation.

  3. Snakes of the Guianan region

    NARCIS (Netherlands)

    Hoogmoed, M.S.

    1982-01-01

    The study of snaks from the Guianan region got an early start in 1705 when several species were pictured by Merian. As relatively large proportion of the snakes described by Linnaeus originated from Surinam. Interest for and knowledge of this group of animals steadily increased in the 18th and 19th

  4. Regina rigida (glossy crayfish snake)

    Science.gov (United States)

    David A. Steen; James A. Stiles; Sierra H. Stiles; Craig Guyer; Josh B. Pierce; D. Craig Rudolph; Lora L. Smith

    2011-01-01

    The overland movements and upland habitat use of wetland-associated reptiles has important conservation implications (Semlitsch and Bodie 2003. Conserv. BioI. 17:1219-1228). However, for many species, particularly snakes, we lack a basic understanding of spatial ecology and habitat use. Regina rigida is a poorly known species for which "observations of any kind...

  5. Proteomic comparisons of venoms of long-term captive and recently wild-caught Eastern brown snakes (Pseudonaja textilis) indicate venom does not change due to captivity.

    Science.gov (United States)

    McCleary, Ryan J R; Sridharan, Sindhuja; Dunstan, Nathan L; Mirtschin, Peter J; Kini, R Manjunatha

    2016-07-20

    Snake venom is a highly variable phenotypic character, and its variation and rapid evolution are important because of human health implications. Because much snake antivenom is produced from captive animals, understanding the effects of captivity on venom composition is important. Here, we have evaluated toxin profiles from six long-term (LT) captive and six recently wild-caught (RC) eastern brown snakes, Pseudonaja textilis, utilizing gel electrophoresis, HPLC-MS, and shotgun proteomics. We identified proteins belonging to the three-finger toxins, group C prothrombin activators, Kunitz-type serine protease inhibitors, and phospholipases A2, among others. Although crude venom HPLC analysis showed LT snakes to be higher in some small molecular weight toxins, presence/absence patterns showed no correlation with time in captivity. Shotgun proteomics indicated the presence of similar toxin families among individuals but with variation in protein species. Although no venom sample contained all the phospholipase A2 subunits that form the textilotoxin, all did contain both prothrombin activator subunits. This study indicates that captivity has limited effects on venom composition, that venom variation is high, and that venom composition may be correlated to geographic distribution. Through proteomic comparisons, we show that protein variation within LT and RC groups of snakes (Pseudonaja textilis) is high, thereby resulting in no discernible differences in venom composition between groups. We utilize complementary techniques to characterize the venom proteomes of 12 individual snakes from our study area, and indicate that individuals captured close to one another have more similar venom gel electrophoresis patterns than those captured at more distant locations. These data are important for understanding natural variation in and potential effects of captivity on venom composition. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Antivenom Cross-Neutralization of the Venoms of Hydrophis schistosus and Hydrophis curtus, Two Common Sea Snakes in Malaysian Waters

    Directory of Open Access Journals (Sweden)

    Choo Hock Tan

    2015-02-01

    Full Text Available Sea snake envenomation is a serious occupational hazard in tropical waters. In Malaysia, the beaked sea snake (Hydrophis schistosus, formerly known as Enhydrina schistosa and the spine-bellied sea snake (Hydrophis curtus, formerly known as Lapemis curtus or Lapemis hardwickii are two commonly encountered species. Australian CSL sea snake antivenom is the definitive treatment for sea snake envenomation; it is unfortunately extremely costly locally and is not widely available or adequately stocked in local hospitals. This study investigated the cross-neutralizing potential of three regionally produced anti-cobra antivenoms against the venoms of Malaysian H. schistosus and H. curtus. All three antivenoms conferred paraspecific protection from sea snake venom lethality in mice, with potency increasing in the following order: Taiwan bivalent antivenom < Thai monocled cobra monovalent antivenom < Thai neuro polyvalent antivenom (NPAV. NPAV demonstrated cross-neutralizing potencies of 0.4 mg/vial for H. schistosus venom and 0.8 mg/vial for H. curtus, which translates to a dose of less than 20 vials of NPAV to neutralize an average amount of sea snake venom per bite (inferred from venom milking. The cross-neutralization activity was supported by ELISA cross-reactivity between NPAV and the venoms of H. schistosus (58.4% and H. curtus (70.4%. These findings revealed the potential of NPAV as a second-line treatment for sea snake envenomation in the region. Further profiling of the cross-neutralization activity should address the antivenomic basis using purified toxin-based assays.

  7. Antivenom Cross-Neutralization of the Venoms of Hydrophis schistosus and Hydrophis curtus, Two Common Sea Snakes in Malaysian Waters

    Science.gov (United States)

    Tan, Choo Hock; Tan, Nget Hong; Tan, Kae Yi; Kwong, Kok Onn

    2015-01-01

    Sea snake envenomation is a serious occupational hazard in tropical waters. In Malaysia, the beaked sea snake (Hydrophis schistosus, formerly known as Enhydrina schistosa) and the spine-bellied sea snake (Hydrophis curtus, formerly known as Lapemis curtus or Lapemis hardwickii) are two commonly encountered species. Australian CSL sea snake antivenom is the definitive treatment for sea snake envenomation; it is unfortunately extremely costly locally and is not widely available or adequately stocked in local hospitals. This study investigated the cross-neutralizing potential of three regionally produced anti-cobra antivenoms against the venoms of Malaysian H. schistosus and H. curtus. All three antivenoms conferred paraspecific protection from sea snake venom lethality in mice, with potency increasing in the following order: Taiwan bivalent antivenom < Thai monocled cobra monovalent antivenom < Thai neuro polyvalent antivenom (NPAV). NPAV demonstrated cross-neutralizing potencies of 0.4 mg/vial for H. schistosus venom and 0.8 mg/vial for H. curtus, which translates to a dose of less than 20 vials of NPAV to neutralize an average amount of sea snake venom per bite (inferred from venom milking). The cross-neutralization activity was supported by ELISA cross-reactivity between NPAV and the venoms of H. schistosus (58.4%) and H. curtus (70.4%). These findings revealed the potential of NPAV as a second-line treatment for sea snake envenomation in the region. Further profiling of the cross-neutralization activity should address the antivenomic basis using purified toxin-based assays. PMID:25690691

  8. The Burmese python genome reveals the molecular basis for extreme adaptation in snakes.

    Science.gov (United States)

    Castoe, Todd A; de Koning, A P Jason; Hall, Kathryn T; Card, Daren C; Schield, Drew R; Fujita, Matthew K; Ruggiero, Robert P; Degner, Jack F; Daza, Juan M; Gu, Wanjun; Reyes-Velasco, Jacobo; Shaney, Kyle J; Castoe, Jill M; Fox, Samuel E; Poole, Alex W; Polanco, Daniel; Dobry, Jason; Vandewege, Michael W; Li, Qing; Schott, Ryan K; Kapusta, Aurélie; Minx, Patrick; Feschotte, Cédric; Uetz, Peter; Ray, David A; Hoffmann, Federico G; Bogden, Robert; Smith, Eric N; Chang, Belinda S W; Vonk, Freek J; Casewell, Nicholas R; Henkel, Christiaan V; Richardson, Michael K; Mackessy, Stephen P; Bronikowski, Anne M; Bronikowsi, Anne M; Yandell, Mark; Warren, Wesley C; Secor, Stephen M; Pollock, David D

    2013-12-17

    Snakes possess many extreme morphological and physiological adaptations. Identification of the molecular basis of these traits can provide novel understanding for vertebrate biology and medicine. Here, we study snake biology using the genome sequence of the Burmese python (Python molurus bivittatus), a model of extreme physiological and metabolic adaptation. We compare the python and king cobra genomes along with genomic samples from other snakes and perform transcriptome analysis to gain insights into the extreme phenotypes of the python. We discovered rapid and massive transcriptional responses in multiple organ systems that occur on feeding and coordinate major changes in organ size and function. Intriguingly, the homologs of these genes in humans are associated with metabolism, development, and pathology. We also found that many snake metabolic genes have undergone positive selection, which together with the rapid evolution of mitochondrial proteins, provides evidence for extensive adaptive redesign of snake metabolic pathways. Additional evidence for molecular adaptation and gene family expansions and contractions is associated with major physiological and phenotypic adaptations in snakes; genes involved are related to cell cycle, development, lungs, eyes, heart, intestine, and skeletal structure, including GRB2-associated binding protein 1, SSH, WNT16, and bone morphogenetic protein 7. Finally, changes in repetitive DNA content, guanine-cytosine isochore structure, and nucleotide substitution rates indicate major shifts in the structure and evolution of snake genomes compared with other amniotes. Phenotypic and physiological novelty in snakes seems to be driven by system-wide coordination of protein adaptation, gene expression, and changes in the structure of the genome.

  9. Fucosylation and protein glycosylation create functional receptors for cholera toxin

    DEFF Research Database (Denmark)

    Wands, Amberlyn M; Fujita, Akiko; McCombs, Janet E

    2015-01-01

    Cholera toxin (CT) enters and intoxicates host cells after binding cell surface receptors using its B subunit (CTB). The ganglioside (glycolipid) GM1 is thought to be the sole CT receptor; however, the mechanism by which CTB binding to GM1 mediates internalization of CT remains enigmatic. Here we...... in normal human intestinal epithelia and could play a role in cholera....

  10. Multivalent carbohydrate inhibitors of bacterial lectins and toxins

    NARCIS (Netherlands)

    Fu, O.

    2015-01-01

    Bacteria and their toxins often carry proteins on their surface binding to specific components of tissue cells or the extracellular matrix. In many cases the components are carbohydrate structures. The adhesion of these carbohydrate-binding proteins, named lectins, to human glycoconjugates is a

  11. Effects and mechanisms of Bacillus thuringiensis crystal toxins for mosquito larvae.

    Science.gov (United States)

    Zhang, Qi; Hua, Gang; Adang, Michael J

    2017-10-01

    Bacillus thuringiensis is a Gram-positive aerobic bacterium that produces insecticidal crystalline inclusions during sporulation phases of the mother cell. The virulence factor, known as parasporal crystals, is composed of Cry and Cyt toxins. Most Cry toxins display a common 3-domain topology. Cry toxins exert intoxication through toxin activation, receptor binding and pore formation in a suitable larval gut environment. The mosquitocidal toxins of Bt subsp. israelensis (Bti) were found to be highly active against mosquito larvae and are widely used for vector control. Bt subsp. jegathesan is another strain which possesses high potency against broad range of mosquito larvae. The present review summarizes characterized receptors for Cry toxins in mosquito larvae, and will also discuss the diversity and effects of 3-D mosquitocidal Cry toxin and the ongoing research for Cry toxin mechanisms generated from investigations of lepidopteran and dipteran larvae. © 2016 Institute of Zoology, Chinese Academy of Sciences.

  12. Antitumoral Potential of Tunisian Snake Venoms Secreted Phospholipases A2

    Directory of Open Access Journals (Sweden)

    Raoudha Zouari-Kessentini

    2013-01-01

    Full Text Available Phospholipases type A2 (PLA2s are the most abundant proteins found in Viperidae snake venom. They are quite fascinating from both a biological and structural point of view. Despite similarity in their structures and common catalytic properties, they exhibit a wide spectrum of pharmacological activities. Besides being hydrolases, secreted phospholipases A2 (sPLA2 are an important group of toxins, whose action at the molecular level is still a matter of debate. These proteins can display toxic effects by different mechanisms. In addition to neurotoxicity, myotoxicity, hemolytic activity, antibacterial, anticoagulant, and antiplatelet effects, some venom PLA2s show antitumor and antiangiogenic activities by mechanisms independent of their enzymatic activity. This paper aims to discuss original finding against anti-tumor and anti-angiogenic activities of sPLA2 isolated from Tunisian vipers: Cerastes cerastes and Macrovipera lebetina, representing new tools to target specific integrins, mainly, and integrins.

  13. Antitumoral Potential of Tunisian Snake Venoms Secreted Phospholipases A2

    Science.gov (United States)

    Zouari-Kessentini, Raoudha; Srairi-Abid, Najet; Bazaa, Amine; El Ayeb, Mohamed; Luis, Jose; Marrakchi, Naziha

    2013-01-01

    Phospholipases type A2 (PLA2s) are the most abundant proteins found in Viperidae snake venom. They are quite fascinating from both a biological and structural point of view. Despite similarity in their structures and common catalytic properties, they exhibit a wide spectrum of pharmacological activities. Besides being hydrolases, secreted phospholipases A2 (sPLA2) are an important group of toxins, whose action at the molecular level is still a matter of debate. These proteins can display toxic effects by different mechanisms. In addition to neurotoxicity, myotoxicity, hemolytic activity, antibacterial, anticoagulant, and antiplatelet effects, some venom PLA2s show antitumor and antiangiogenic activities by mechanisms independent of their enzymatic activity. This paper aims to discuss original finding against anti-tumor and anti-angiogenic activities of sPLA2 isolated from Tunisian vipers: Cerastes cerastes and Macrovipera lebetina, representing new tools to target specific integrins, mainly, α5β1 and αv integrins. PMID:23509718

  14. Neutralization of the Principal Toxins from the Venoms of Thai Naja kaouthia and Malaysian Hydrophis schistosus: Insights into Toxin-Specific Neutralization by Two Different Antivenoms.

    Science.gov (United States)

    Tan, Kae Yi; Tan, Choo Hock; Fung, Shin Yee; Tan, Nget Hong

    2016-03-26

    Antivenom neutralization against cobra venoms is generally low in potency, presumably due to poor toxin-specific immunoreactivity. This study aimed to investigate the effectiveness of two elapid antivenoms to neutralize the principal toxins purified from the venoms of the Thai monocled cobra (Naja kaouthia, Nk-T) and the Malaysian beaked sea snake (Hydrophis schistosus, Hs-M). In mice, N. kaouthia Monovalent Antivenom (NKMAV) neutralization against Nk-T long neurotoxin (LNTX) and cytotoxin was moderate (potency of 2.89-6.44 mg toxin/g antivenom protein) but poor against the short neurotoxin (SNTX) (1.33 mg/g). Its cross-neutralization against Hs-M LNTX of Hs-M is compatible (0.18 mg/g) but much weaker against Hs-M SNTX (0.22 mg/g). Using CSL (Seqirus Limited) Sea Snake Antivenom (SSAV), we observed consistently weak neutralization of antivenom against SNTX of both species, suggesting that this is the limiting factor on the potency of antivenom neutralization against venoms containing SNTX. Nevertheless, SSAV outperformed NKMAV in neutralizing SNTXs of both species (0.61-2.49 mg/g). The superior efficacy of SSAV against SNTX is probably partly attributable to the high abundance of SNTX in sea snake venom used as immunogen in SSAV production. The findings indicate that improving the potency of cobra antivenom may be possible with a proper immunogen formulation that seeks to overcome the limitation on SNTX immunoreactivity.

  15. Neutralization of the Principal Toxins from the Venoms of Thai Naja kaouthia and Malaysian Hydrophis schistosus: Insights into Toxin-Specific Neutralization by Two Different Antivenoms

    Directory of Open Access Journals (Sweden)

    Kae Yi Tan

    2016-03-01

    Full Text Available Antivenom neutralization against cobra venoms is generally low in potency, presumably due to poor toxin-specific immunoreactivity. This study aimed to investigate the effectiveness of two elapid antivenoms to neutralize the principal toxins purified from the venoms of the Thai monocled cobra (Naja kaouthia, Nk-T and the Malaysian beaked sea snake (Hydrophis schistosus, Hs-M. In mice, N. kaouthia Monovalent Antivenom (NKMAV neutralization against Nk-T long neurotoxin (LNTX and cytotoxin was moderate (potency of 2.89–6.44 mg toxin/g antivenom protein but poor against the short neurotoxin (SNTX (1.33 mg/g. Its cross-neutralization against Hs-M LNTX of Hs-M is compatible (0.18 mg/g but much weaker against Hs-M SNTX (0.22 mg/g. Using CSL (Seqirus Limited Sea Snake Antivenom (SSAV, we observed consistently weak neutralization of antivenom against SNTX of both species, suggesting that this is the limiting factor on the potency of antivenom neutralization against venoms containing SNTX. Nevertheless, SSAV outperformed NKMAV in neutralizing SNTXs of both species (0.61–2.49 mg/g. The superior efficacy of SSAV against SNTX is probably partly attributable to the high abundance of SNTX in sea snake venom used as immunogen in SSAV production. The findings indicate that improving the potency of cobra antivenom may be possible with a proper immunogen formulation that seeks to overcome the limitation on SNTX immunoreactivity.

  16. Neutralization of the Principal Toxins from the Venoms of Thai Naja kaouthia and Malaysian Hydrophis schistosus: Insights into Toxin-Specific Neutralization by Two Different Antivenoms

    Science.gov (United States)

    Tan, Kae Yi; Tan, Choo Hock; Fung, Shin Yee; Tan, Nget Hong

    2016-01-01

    Antivenom neutralization against cobra venoms is generally low in potency, presumably due to poor toxin-specific immunoreactivity. This study aimed to investigate the effectiveness of two elapid antivenoms to neutralize the principal toxins purified from the venoms of the Thai monocled cobra (Naja kaouthia, Nk-T) and the Malaysian beaked sea snake (Hydrophis schistosus, Hs-M). In mice, N. kaouthia Monovalent Antivenom (NKMAV) neutralization against Nk-T long neurotoxin (LNTX) and cytotoxin was moderate (potency of 2.89–6.44 mg toxin/g antivenom protein) but poor against the short neurotoxin (SNTX) (1.33 mg/g). Its cross-neutralization against Hs-M LNTX of Hs-M is compatible (0.18 mg/g) but much weaker against Hs-M SNTX (0.22 mg/g). Using CSL (Seqirus Limited) Sea Snake Antivenom (SSAV), we observed consistently weak neutralization of antivenom against SNTX of both species, suggesting that this is the limiting factor on the potency of antivenom neutralization against venoms containing SNTX. Nevertheless, SSAV outperformed NKMAV in neutralizing SNTXs of both species (0.61–2.49 mg/g). The superior efficacy of SSAV against SNTX is probably partly attributable to the high abundance of SNTX in sea snake venom used as immunogen in SSAV production. The findings indicate that improving the potency of cobra antivenom may be possible with a proper immunogen formulation that seeks to overcome the limitation on SNTX immunoreactivity. PMID:27023606

  17. Growth factor toxin fusion proteins for the treatment of leukemia: Preclinical animal studies relevant for human acute myeloid leukemia

    NARCIS (Netherlands)

    H. Rozemuller (Henk)

    1997-01-01

    textabstractIn the development of new therapeutic agents to treat malignancies. bacterial and plant toxins are being investigated. Targeting cells with these toxins has been facilitated by chemical conjugation or genetic engineering of the toxin to proteins with cellular binding potential, such as

  18. A mechanism of the thearubigin fraction of black tea (Camellia sinensis) extract protecting against the effect of tetanus toxin.

    Science.gov (United States)

    Satoh, Eiki; Ishii, Toshiaki; Shimizu, Yoshio; Sawamura, Shin-ichi; Nishimura, Masakazu

    2002-12-01

    The aim of the present study was to elucidate the mechanism of the protective effect of black tea extract's thearubigin fraction against the action of tetanus toxin. The effects of thearubigin fraction extracted from a black tea infusion were examined for neuromuscular blocking action on tetanus toxin in mouse phrenic nerve-diaphragm preparations and on the binding of this toxin to the synaptosomal membrane preparations of rat cerebral cortices. The interaction between tetanus toxin and thearubigin fraction was also investigated. Tetanus toxin (4 micrograms/ml) abolished indirect twitches in mouse phrenic nerve-diaphragm preparations within 150 min. Thearubigin fraction mixed with tetanus toxin blocked the inhibitory effect of the toxin. Mixing iodinated toxin with thearubigin fraction inhibited the specific binding of [125I]tetanus toxin to the synaptosomal membrane preparation. The effects of thearubigin fraction were dose-dependent. The elution profile of [125I]tetanus toxin on Sephadex G-50 column chromatography was different from that of toxin mixed with thearubigin fraction. These findings indicate that thearubigin fraction protects against the action of tetanus toxin by binding with the toxin.

  19. Unusual neurotoxic envenomations by Vipera aspis aspis snakes in France.

    Science.gov (United States)

    de Haro, L; Robbe-Vincent, A; Saliou, B; Valli, M; Bon, C; Choumet, V

    2002-03-01

    Vipera aspis aspis (V.a.a.) is the most dangerous poisonous snake in South-Eastern France. The clinical symptoms observed after V.a.a. envenomations involve mostly local signs (pain, edema) associated in the more severe cases with systemic symptoms (gastro-intestinal and cardiovascular manifestations). Since 1992, several unusual cases of moderate and severe 'neurotoxic' envenomations by V.a.a. snakes have been reported in a very localized area in South-Eastern France. Most of the human patients mainly suffered neurological signs owing to cephalic muscle paralysis. Drowsiness and dyspnea were observed for the most severe cases. Envenomed animals suffered respiratory distress and paralysis. The local signs were never as severe as observed after envenomations by vipers in other French regions. Human patients with moderate or severe clinical features received two intravenous injections of Viperfav antivenom, the first dose inducing the decrease of the neurological signs and the second reducing significantly the edema. Neurotoxic components immunologically cross-reacting with toxins from V. ammodytes ammodytes venom from Eastern Europe were detected in the blood of all patients suffering neurological symptoms after a V.a.a. bite. The protective efficacy of various antivenoms was evaluated in mice. The existence of geographical variations in the composition of V.a.a. venom emphasizes on the use of polyvalent antivenom in the treatment of viper envenomations in France.

  20. Crystal structure of Clostridium difficile toxin A

    Energy Technology Data Exchange (ETDEWEB)

    Chumbler, Nicole M.; Rutherford, Stacey A.; Zhang, Zhifen; Farrow, Melissa A.; Lisher, John P.; Farquhar, Erik; Giedroc, David P.; Spiller, Benjamin W.; Melnyk, Roman A.; Lacy, D. Borden

    2016-01-11

    Clostridium difficile infection is the leading cause of hospital-acquired diarrhoea and pseudomembranous colitis. Disease is mediated by the actions of two toxins, TcdA and TcdB, which cause the diarrhoea, as well as inflammation and necrosis within the colon. The toxins are large (308 and 270 kDa, respectively), homologous (47% amino acid identity) glucosyltransferases that target small GTPases within the host. The multidomain toxins enter cells by receptor-mediated endocytosis and, upon exposure to the low pH of the endosome, insert into and deliver two enzymatic domains across the membrane. Eukaryotic inositol-hexakisphosphate (InsP6) binds an autoprocessing domain to activate a proteolysis event that releases the N-terminal glucosyltransferase domain into the cytosol. Here, we report the crystal structure of a 1,832-amino-acid fragment of TcdA (TcdA1832), which reveals a requirement for zinc in the mechanism of toxin autoprocessing and an extended delivery domain that serves as a scaffold for the hydrophobic α-helices involved in pH-dependent pore formation. A surface loop of the delivery domain whose sequence is strictly conserved among all large clostridial toxins is shown to be functionally important, and is highlighted for future efforts in the development of vaccines and novel therapeutics.

  1. Structure, biological functions and applications of the AB5 toxins.

    Science.gov (United States)

    Beddoe, Travis; Paton, Adrienne W; Le Nours, Jérôme; Rossjohn, Jamie; Paton, James C

    2010-07-01

    AB(5) toxins are important virulence factors for several major bacterial pathogens, including Bordetella pertussis, Vibrio cholerae, Shigella dysenteriae and at least two distinct pathotypes of Escherichia coli. The AB(5) toxins are so named because they comprise a catalytic A-subunit, which is responsible for disruption of essential host functions, and a pentameric B-subunit that binds to specific glycan receptors on the target cell surface. The molecular mechanisms by which the AB(5) toxins cause disease have been largely unravelled, including recent insights into a novel AB(5) toxin family, subtilase cytotoxin (SubAB). Furthermore, AB(5) toxins have become a valuable tool for studying fundamental cellular functions, and are now being investigated for potential applications in the clinical treatment of human diseases. Copyright 2010 Elsevier Ltd. All rights reserved.

  2. Immunochemistry of sea anemone toxins: structure-antigenicity relationships and toxin-receptor interactions probed by antibodies specific for one antigenic

    Energy Technology Data Exchange (ETDEWEB)

    Ayeb, M.E.; Bahraoui, E.M.; Granier, C.; Beress, L.; Rochat, H.

    1986-11-04

    Two antibody subpopulations directed against Anemonia sulcata toxin I or II have been purified by immunoaffinity chromatography. These antibodies are specific for a single antigenic region and were used in a structure-antigenicity relationship study using homologous toxins and chemically modified derivatives of A. sulcata toxin II. Asp-7 and/or Asp=9 and Gln-47 of toxin II were found to be implicated in the antigenic region recognized by the two antibody subpopulations. On the contrary, Arg-14, Lys-35, -36, and -46, and ..cap alpha..-NH/sub 2/ of the glycine residue of A. sulcata toxin II are not involved in the corresponding antigenic region. When assayed for interaction with the sodium channel, the antigenic region of toxin II, including Asp-9 and Gln-47, appeared fully accessible to its specific antibodies, suggesting that it is not involved in the binding of the toxin to its receptor.

  3. Transcriptomic basis for an antiserum against Micrurus corallinus (coral snake) venom.

    Science.gov (United States)

    Leão, Luciana I; Ho, Paulo L; Junqueira-de-Azevedo, Inacio de L M

    2009-03-16

    Micrurus corallinus (coral snake) is a tropical forest snake belonging to the family Elapidae. Its venom shows a high neurotoxicity associated with pre- and post-synaptic toxins, causing diaphragm paralysis, which may result in death. In spite of a relatively small incidence of accidents, serum therapy is crucial for those bitten. However, the adequate production of antiserum is hampered by the difficulty in obtaining sufficient amounts of venom from a small snake with demanding breeding conditions. In order to elucidate the molecular basis of this venom and to uncover possible immunogens for an antiserum, we generated expressed sequences tags (ESTs) from its venom glands and analyzed the transcriptomic profile. In addition, their immunogenicity was tested using DNA immunization. A total of 1438 ESTs were generated and grouped into 611 clusters. Toxin transcripts represented 46% of the total ESTs. The two main toxin classes consisted of three-finger toxins (3FTx) (24%) and phospholipases A(2) (PLA(2)s) (15%). However, 8 other classes of toxins were present, including C-type lectins, natriuretic peptide precursors and even high-molecular mass components such as metalloproteases and L-amino acid oxidases. Each class included an assortment of isoforms, some showing evidence of alternative splicing and domain deletions. Five antigenic candidates were selected (four 3FTx and one PLA(2)) and used for a preliminary study of DNA immunization. The immunological response showed that the sera from the immunized animals were able to recognize the recombinant antigens. Besides an improvement in our knowledge of the composition of coral snake venoms, which are very poorly known when compared to Old World elapids, the expression profile suggests abundant and diversified components that may be used in future antiserum formulation. As recombinant production of venom antigens frequently fails due to complex disulfide arrangements, DNA immunization may be a viable alternative. In

  4. Transcriptomic basis for an antiserum against Micrurus corallinus (coral snake venom

    Directory of Open Access Journals (Sweden)

    Ho Paulo L

    2009-03-01

    Full Text Available Abstract Background Micrurus corallinus (coral snake is a tropical forest snake belonging to the family Elapidae. Its venom shows a high neurotoxicity associated with pre- and post-synaptic toxins, causing diaphragm paralysis, which may result in death. In spite of a relatively small incidence of accidents, serum therapy is crucial for those bitten. However, the adequate production of antiserum is hampered by the difficulty in obtaining sufficient amounts of venom from a small snake with demanding breeding conditions. In order to elucidate the molecular basis of this venom and to uncover possible immunogens for an antiserum, we generated expressed sequences tags (ESTs from its venom glands and analyzed the transcriptomic profile. In addition, their immunogenicity was tested using DNA immunization. Results A total of 1438 ESTs were generated and grouped into 611 clusters. Toxin transcripts represented 46% of the total ESTs. The two main toxin classes consisted of three-finger toxins (3FTx (24% and phospholipases A2 (PLA2s (15%. However, 8 other classes of toxins were present, including C-type lectins, natriuretic peptide precursors and even high-molecular mass components such as metalloproteases and L-amino acid oxidases. Each class included an assortment of isoforms, some showing evidence of alternative splicing and domain deletions. Five antigenic candidates were selected (four 3FTx and one PLA2 and used for a preliminary study of DNA immunization. The immunological response showed that the sera from the immunized animals were able to recognize the recombinant antigens. Conclusion Besides an improvement in our knowledge of the composition of coral snake venoms, which are very poorly known when compared to Old World elapids, the expression profile suggests abundant and diversified components that may be used in future antiserum formulation. As recombinant production of venom antigens frequently fails due to complex disulfide arrangements, DNA

  5. Protein-bound toxins: has the Cinderella of uraemic toxins turned into a princess?

    Science.gov (United States)

    Liabeuf, Sophie; Villain, Cédric; Massy, Ziad A

    2016-12-01

    Chronic kidney disease (CKD) has emerged as a global public health problem. Although the incidence and prevalence of CKD vary from one country to another, the estimated worldwide prevalence is 8-16%. The complications associated with CKD include progression to end-stage renal disease (ESRD), mineral and bone disorders, anaemia, cognitive decline and elevated all-cause and cardiovascular (CV) mortality. As a result of progressive nephron loss, patients with late-stage CKD are permanently exposed to uraemic toxins. These toxins have been classified into three groups as a function of the molecular mass: small water-soluble molecules, middle molecules and protein-bound uraemic toxins. The compounds can also be classified according to their origin (i.e. microbial or not) or their protein-binding ability. The present review will focus on the best-characterized protein-bound uraemic toxins, namely indoxylsulfate (IS), indole acetic acid (IAA) and p-cresylsulfate (PCS, a cresol metabolite). Recent research suggests that these toxins accelerate the progression of CV disease, kidney disease, bone disorders and neurological complications. Lastly, we review therapeutic approaches that can be used to decrease toxin levels. © 2016 The Author(s). published by Portland Press Limited on behalf of the Biochemical Society.

  6. The Study on the Snake by TOXICON

    Directory of Open Access Journals (Sweden)

    Sung-wook Kim

    2003-06-01

    Full Text Available The study was carried out to investigate the researches of Snake which was published papers in the TOXICON(1990-2.000, one of the most famous Journal of toxicology. And the results were as follows: 1. The number related with Snake is 195papers. 2. There were great papers related wih Cobra, and next is Tigris, Viper, etc. 3. There were great papers related wih protein in the composition of snake venom. 4. There were great papers related wih neurotoxin in the research of poisonous character. 5. There were great papers related wih Viper according to the anticoagulation. 6. Eight papers were published to study the immune response of snake venom. 7. The papers of molecular study of snake venom were seven. 8. The papers of anti-snake venom study were three.

  7. Observations of Snake Resonance in RHIC

    CERN Document Server

    Bai, Mei; Lee, Shyh-Yuan; Lin, Fanglei; MacKay, William; Ptitsyn, Vadim; Roser, Thomas; Tepikian, Steven

    2005-01-01

    Siberian snakes now become essential in the polarized proton acceleration. With proper configuration of Siberian snakes, the spin precession tune of the beam becomes $\\frac{1}{2}$ which avoids all the spin depolarizing resonance. However, the enhancement of the perturbations on the spin motion can still occur when the betatron tune is near some low order fractional numbers, called snake resonances, and the beam can be depolarized when passing through the resonance. The snake resonances have been confirmed in the spin tracking calculations, and observed in RHIC with polarized proton beam. Equipped with two full Siberian snakes in each ring, RHIC provides us a perfect facility for snake resonance studies. This paper presents latest experimental results. New insights are also discussed.

  8. Use of a synthetic biosensor for neutralizing activity-biased selection of monoclonal antibodies against atroxlysin-I, an hemorrhagic metalloproteinase from Bothrops atrox snake venom.

    Directory of Open Access Journals (Sweden)

    Francisco Santos Schneider

    2014-04-01

    Full Text Available BACKGROUND: The snake Bothrops atrox is responsible for the majority of envenomings in the northern region of South America. Severe local effects, including hemorrhage, which are mainly caused by snake venom metalloproteinases (SVMPs, are not fully neutralized by conventional serum therapy. Little is known about the immunochemistry of the P-I SVMPs since few monoclonal antibodies (mAbs against these molecules have been obtained. In addition, producing toxin-neutralizing mAbs remains very challenging. METHODOLOGY/PRINCIPAL FINDINGS: Here, we report on the set-up of a functional screening based on a synthetic peptide used as a biosensor to select neutralizing mAbs against SVMPs and the successful production of neutralizing mAbs against Atroxlysin-I (Atr-I, a P-I SVMP from B. atrox. Hybridomas producing supernatants with inhibitory effect against the proteolytic activity of Atr-I towards the FRET peptide Abz-LVEALYQ-EDDnp were selected. Six IgG1 Mabs were obtained (named mAbatr1 to mAbatr6 and also two IgM. mAbatrs1, 2, 3 and 6 were purified. All showed a high specific reactivity, recognizing only Atr-I and B. atrox venom in ELISA and a high affinity, showing equilibrium constants in the nM range for Atr-I. These mAbatrs were not able to bind to Atr-I overlapping peptides, suggesting that they recognize conformational epitopes. CONCLUSIONS/SIGNIFICANCE: For the first time a functional screening based on a synthetic biosensor was successfully used for the selection of neutralizing mAbs against SVMPs.

  9. Stabilising the Integrity of Snake Venom mRNA Stored under Tropical Field Conditions Expands Research Horizons.

    Science.gov (United States)

    Whiteley, Gareth; Logan, Rhiannon A E; Leung, Kam-Yin D; Newberry, Fiona J; Rowley, Paul D; Dunbar, John P; Wagstaff, Simon C; Casewell, Nicholas R; Harrison, Robert A

    2016-06-01

    Snake venoms contain many proteinaceous toxins that can cause severe pathology and mortality in snakebite victims. Interestingly, mRNA encoding such toxins can be recovered directly from venom, although yields are low and quality is unknown. It also remains unclear whether such RNA contains information about toxin isoforms and whether it is representative of mRNA recovered from conventional sources, such as the venom gland. Answering these questions will address the feasibility of using venom-derived RNA for future research relevant to biomedical and antivenom applications. Venom was extracted from several species of snake, including both members of the Viperidae and Elapidae, and either lyophilized or immediately added to TRIzol reagent. TRIzol-treated venom was incubated at a range of temperatures (4-37°C) for a range of durations (0-48 hours), followed by subsequent RNA isolation and assessments of RNA quantity and quality. Subsequently, full-length toxin transcripts were targeted for PCR amplification and Sanger sequencing. TRIzol-treated venom yielded total RNA of greater quantity and quality than lyophilized venom, and with quality comparable to venom gland-derived RNA. Full-length sequences from multiple Viperidae and Elapidae toxin families were successfully PCR amplified from TRIzol-treated venom RNA. We demonstrated that venom can be stored in TRIzol for 48 hours at 4-19°C, and 8 hours at 37°C, at minimal cost to RNA quality, and found that venom RNA encoded multiple toxin isoforms that seemed homologous (98-99% identity) to those found in the venom gland. The non-invasive experimental modifications we propose will facilitate the future investigation of venom composition by using venom as an alternative source to venom gland tissue for RNA-based studies, thus obviating the undesirable need to sacrifice snakes for such research purposes. In addition, they expand research horizons to rare, endangered or protected snake species and provide more

  10. Microalgal toxin(s): characteristics and importance

    African Journals Online (AJOL)

    Prokaryotic and eukaryotic microalgae produce a wide array of compounds with biological activities. These include antibiotics, algicides, toxins, pharmaceutically active compounds and plant growth regulators. Toxic microalgae, in this sense, are common only among the cyanobacteria and dinoflagellates. The microalgal ...

  11. Snake Venom Peptides and Low Mass Proteins: Molecular Tools and Therapeutic Agents.

    Science.gov (United States)

    Almeida, J R; Resende, L M; Watanabe, R K; Carregari, V C; Huancahuire-Vega, S; da S Caldeira, C A; Coutinho-Neto, A; Soares, A M; Vale, N; de C Gomes, P A; Marangoni, S; de A Calderon, L; Da Silva, S L

    2017-01-01

    Snake venoms are natural sources of biologically active molecules that are able to act selectively and specifically on different cellular targets, modulating physiological functions. Thus, these mixtures, composed mainly of proteins and peptides, provide ample and challenging opportunities and a diversified molecular architecture to design and develop tools and agents of scientific and therapeutic interest. Among these components, peptides and small proteins play diverse roles in numerous physiological processes, exerting a wide range of pharmacological activities, such as antimicrobial, antihypertensive, analgesic, antitumor, analgesic, among others. The pharmaceutical and cosmetic industries have recognized the huge potential of these privileged frameworks and believe them to be a promising alternative to contemporary drugs. A number of natural or synthetic peptides from snake venoms have already found preclinical or clinical applications for the treatment of pain, hypertension, cardiovascular diseases and aging skin. A well-known example is captopril, whose natural peptide precursor was isolated from Bothrops jararaca snake venom, which is a peptide-based drug that inhibits the angiotensin-converting enzyme, producing an anti-hypertensive effect. The present review looks at the main peptides (natriuretic peptides, bradykinin-potentiating peptides and sarafotoxins) and low mass proteins (crotamine, disintegrins and three-Finger toxins) from snake venoms, as well as synthetic peptides inspired by them, describing their biochemical, structural and physiological features, as well as their applications as research tools and therapeutic agents. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  12. Coral snake venoms: mode of action and pathophysiology of experimental envenomation

    Directory of Open Access Journals (Sweden)

    Oswald Vital Brazil

    1987-06-01

    Full Text Available Coral snakes, the New World Elapidae, are included in the genera Micniroides and Micrurus. The genus Mlcrurus comprises nearly all coral snake species and those which are responsible for human snake-bite accidents. The following generalizations concerning the effects induced by their venoms, and their venom-properties can be made. Coral snake venoms are neurotoxic, producing loss of muscle strenght and death by respiratory paralysis. Local edema and necrosis are not induced nor blood coagulation or hemorrhages. Proteolysis activity is absent or of very low grade. They display phospholipase A2 activity. Nephrotoxic effects are not evoked. The main toxins from elapid venoms are postsynaptic and presynaptic neurotoxins and cardiotoxins. Phospholipases A2 endowed with myonecrotic or cardiotoxin-like properties are important toxic components from some elapid venoms. The mode of action of Micrurus frontalis, M. lemniscatus, M. corallinus and M. fulvius venoms has been investigated in isolated muscle preparations and is here discussed. It is shown that while M. frontalis and M. lemniscatus venoms must contain only neurotoxins that act at the cholinergic end-plate receptor (postsynaptic neurotoxins, M. corallinus venom also inhibits evoked acetylcholine release by the motor nerve endings (presynaptic neurotoxin-like effect and M. fulvius induces muscle fiber membrane depolarization (cardiotoxin-like effect. The effects produced by M. corallinus and M. fulvius venoms in vivo in dogs and M. frontalis venom in dogs and monkeys are also reported.

  13. Snake scales, partial exposure, and the Snake Detection Theory: A human event-related potentials study

    Science.gov (United States)

    Van Strien, Jan W.; Isbell, Lynne A.

    2017-01-01

    Studies of event-related potentials in humans have established larger early posterior negativity (EPN) in response to pictures depicting snakes than to pictures depicting other creatures. Ethological research has recently shown that macaques and wild vervet monkeys respond strongly to partially exposed snake models and scale patterns on the snake skin. Here, we examined whether snake skin patterns and partially exposed snakes elicit a larger EPN in humans. In Task 1, we employed pictures with close-ups of snake skins, lizard skins, and bird plumage. In task 2, we employed pictures of partially exposed snakes, lizards, and birds. Participants watched a random rapid serial visual presentation of these pictures. The EPN was scored as the mean activity (225–300 ms after picture onset) at occipital and parieto-occipital electrodes. Consistent with previous studies, and with the Snake Detection Theory, the EPN was significantly larger for snake skin pictures than for lizard skin and bird plumage pictures, and for lizard skin pictures than for bird plumage pictures. Likewise, the EPN was larger for partially exposed snakes than for partially exposed lizards and birds. The results suggest that the EPN snake effect is partly driven by snake skin scale patterns which are otherwise rare in nature. PMID:28387376

  14. CORAL SNAKE ANTIVENOM PRODUCED IN CHICKENS (Gallus domesticus

    Directory of Open Access Journals (Sweden)

    Irma Aguilar

    2014-01-01

    Full Text Available The production of anti-snake venom from large mammal's blood has been found to be low-yielding and arduous, consequently, antivenom immunoglobulins for treatment are achieved regularly as polyvalent serum. We have standardized an undemanding technique for making purified immunoglobulin IgY antivenom consisting of polyclonal antibodies against coral snake venom in the egg yolk of immunized hens. We have adapted a reported process of antibody purification from egg yolks, and achieved 90% antibody purity. The customized technique consisted of the removal of lipids from distilled water-diluted egg yolks by a freeze–thaw sequence. The specific immunoglobulins were present in the egg yolk for up to 180 days postimmunization. Therefore, by means of small venom quantities, a significant amount of immunoglobulins were found in an adequately purified state (The obtained material contained about 90% pure IgY. The antigen binding of the immunoglobulins was detected by a double immunodiffusion test. Titers of antibodies in the yolk were estimated with a serum protection assay (Median effective dose = ED50 (ED50= 477 mg/kg. Given that breeding hens is economically feasible, egg gathering is noninvasive and the purification of IgY antibodies is quick and easy, chicken immunization is an excellent alternative for the production of polyclonal antibodies. To the best of our knowledge, this is the first coral snake antivenom prepared in birds.

  15. Coral snake antivenom produced in chickens (Gallus domesticus).

    Science.gov (United States)

    Aguilar, Irma; Sánchez, Elda E; Girón, María E; Estrella, Amalid; Guerrero, Belsy; Rodriguez-Acosta, F Alexis

    2014-01-01

    The production of anti-snake venom from large mammal's blood has been found to be low-yielding and arduous, consequently, antivenom immunoglobulins for treatment are achieved regularly as polyvalent serum. We have standardized an undemanding technique for making purified immunoglobulin IgY antivenom consisting of polyclonal antibodies against coral snake venom in the egg yolk of immunized hens. We have adapted a reported process of antibody purification from egg yolks, and achieved 90% antibody purity. The customized technique consisted of the removal of lipids from distilled water-diluted egg yolks by a freeze-thaw sequence. The specific immunoglobulins were present in the egg yolk for up to 180 days postimmunization. Therefore, by means of small venom quantities, a significant amount of immunoglobulins were found in an adequately purified state (The obtained material contained about 90% pure IgY). The antigen binding of the immunoglobulins was detected by a double immunodiffusion test. Titers of antibodies in the yolk were estimated with a serum protection assay (Median effective dose = ED50) (ED50= 477 mg/kg). Given that breeding hens is economically feasible, egg gathering is noninvasive and the purification of IgY antibodies is quick and easy, chicken immunization is an excellent alternative for the production of polyclonal antibodies. To the best of our knowledge, this is the first coral snake antivenom prepared in birds.

  16. Detection of Shiga Toxins by Lateral Flow Assay

    OpenAIRE

    Ching, Kathryn H.; He, Xiaohua; Stanker, Larry H.; Lin, Alice V.; McGarvey, Jeffery A.; Hnasko, Robert

    2015-01-01

    Shiga toxin-producing Escherichia coli (STEC) produce shiga toxins (Stxs) that can cause human disease and death. The contamination of food products with STEC represents a food safety problem that necessitates rapid and effective detection strategies to mitigate risk. In this manuscript, we report the development of a colorimetric lateral flow assay (LFA) for the rapid detection of Stxs in <10 min using a pair of monoclonal antibodies that bind epitopes common to Stx1 and six Stx2 variants...

  17. [Snake envenomation in French Guiana].

    Science.gov (United States)

    Chippaux, J P

    2002-01-01

    French Guiana is a French Overseas Department in South America. Ninety-five percent of the territory is a tropical rainforest. Its rich fauna includes seven families of snakes but only 3 are potentially venomous. Less than 12% of species and, depending on biotope, 10 to 30% of specimens collected are dangerous for humans. The annual incidence of snakebite is less than 50 bites per 100,000 inhabitants overall but increases to 600 per 100,000 for persons active in the rainforest where the risk is highest. The most common envenomation by Viperidae such as Bothrops, which is abundant throughout French Guiana, induces inflammation, necrosis and hemorrhage. Crotalus durissus, a rattlesnake living in coastal savannah, or Micrurus sp cause neuromuscular poisoning. Coral snakes are encountered throughout French Guiana, but envenomation is very rare. Antivenom therapy must be administered by the intravenous route in association with symptomatic treatment and, if necessary, resuscitation in a specialized care unit.

  18. Snake venom antibodies in Ecuadorian Indians.

    Science.gov (United States)

    Theakston, R D; Reid, H A; Larrick, J W; Kaplan, J; Yost, J A

    1981-10-01

    Serum samples from 223 Waorani Indians, a tribe in eastern Ecuador, were investigated by enzyme-linked immunosorbent assay for antibodies to snake venom. Seventy-eight per cent were positive, confirming the highest incidence and mortality from snake bite poisoning yet recorded in the world. Most samples were positive for more than one venom antibody. Antibodies were found to venoms of Bothrops viper in 60% of positive cases, of Micrurus coral snake in 21%, and of the bushmaster, Lachesis muta, in 18%. Further studies are needed to determine whether high venom-antibody levels afford protection against further snake envenoming.

  19. Snake bite in South Asia: a review

    National Research Council Canada - National Science Library

    Alirol, Emilie; Sharma, Sanjib Kumar; Bawaskar, Himmatrao Saluba; Kuch, Ulrich; Chappuis, François

    2010-01-01

    .... Despite increasing knowledge of snake venoms' composition and mode of action, good understanding of clinical features of envenoming and sufficient production of antivenom by Indian manufacturers...

  20. Structural determinants for membrane insertion, pore formation and translocation of Clostridium difficile toxin B.

    Science.gov (United States)

    Genisyuerek, Selda; Papatheodorou, Panagiotis; Guttenberg, Gregor; Schubert, Rolf; Benz, Roland; Aktories, Klaus

    2011-03-01

    Clostridium difficile toxins A and B bind to eukaryotic target cells, are endocytosed and then deliver their N-terminal glucosyltransferase domain after processing into the cytosol. Whereas glucosyltransferase, autoprocessing and cell-binding domains are well defined, structural features involved in toxin delivery are unknown. Here, we studied structural determinants that define membrane insertion, pore formation and translocation of toxin B. Deletion analyses revealed that a large region, covering amino acids 1501-1753 of toxin B, is dispensable for cytotoxicity in Vero cells. Accordingly, a chimeric toxin, consisting of amino acids 1-1550 and the receptor-binding domain of diphtheria toxin, caused cytotoxic effects. A large N-terminal part of toxin B (amino acids 1-829) was not essential for pore formation (measured by (86) Rb(+) release in mammalian cells). Studies using C-terminal truncation fragments of toxin B showed that amino acid residues 1-990 were still capable of inducing fluorescence dye release from large lipid vesicles and led to increased electrical conductance in black lipid membranes. Thereby, we define the minimal pore-forming region of toxin B within amino acid residues 830 and 990. Moreover, we identify within this region a crucial role of the amino acid pair glutamate-970 and glutamate-976 in pore formation of toxin B. © 2011 Blackwell Publishing Ltd.

  1. Cholera toxin A1 residues single alanine substitutional mutation and effect on activity with stimulatory G protein

    OpenAIRE

    Somsri Wiwanitkit; Viroj Wiwanitkit

    2017-01-01

    Cholera is a well-known gastrointestinal infection. The cholera toxin is an important pathological substance in pathogenesis of cholera diarrhea. Cholera toxin is composed of catalytic A1 subunit, an A2 linker, and a homopentameric cell-binding B subunit. In enterocyte, cholera toxin will attach to GM1 ganglioside receptors on the apical membrane and causes retrograde vesicular trafficking to endoplasmic reticulum. At endoplasmic reticulum, cholera toxin A1 is released from the rest of the to...

  2. Analysis of lectin-bound glycoproteins in snake venom from the Elapidae and Viperidae families.

    Science.gov (United States)

    Nawarak, Jiraporn; Phutrakul, Suree; Chen, Shui-Tein

    2004-01-01

    This paper describes an efficient method of studying the glycoproteins found in snake venom. The glycosylation profiles of the Elapidae and Viperidae snake families were analyzed using FITC-labeled lectin glycoconjugates. The Con A-agarose affinity enrichment technique was used to fractionate glycoproteins from the N. naja kaouthia venom. The results revealed a large number of Con A binding glycoproteins, most of which have moderate to high molecular weights. To identify the proteins, the isolated glycoprotein fractions were subjected to two-dimensional electrophoresis and MALDI-TOF MS. Protein sequences were compared with published protein databases to determine for their biological functions.

  3. Structural interactions of a voltage sensor toxin with lipid membranes.

    Science.gov (United States)

    Mihailescu, Mihaela; Krepkiy, Dmitriy; Milescu, Mirela; Gawrisch, Klaus; Swartz, Kenton J; White, Stephen

    2014-12-16

    Protein toxins from tarantula venom alter the activity of diverse ion channel proteins, including voltage, stretch, and ligand-activated cation channels. Although tarantula toxins have been shown to partition into membranes, and the membrane is thought to play an important role in their activity, the structural interactions between these toxins and lipid membranes are poorly understood. Here, we use solid-state NMR and neutron diffraction to investigate the interactions between a voltage sensor toxin (VSTx1) and lipid membranes, with the goal of localizing the toxin in the membrane and determining its influence on membrane structure. Our results demonstrate that VSTx1 localizes to the headgroup region of lipid membranes and produces a thinning of the bilayer. The toxin orients such that many basic residues are in the aqueous phase, all three Trp residues adopt interfacial positions, and several hydrophobic residues are within the membrane interior. One remarkable feature of this preferred orientation is that the surface of the toxin that mediates binding to voltage sensors is ideally positioned within the lipid bilayer to favor complex formation between the toxin and the voltage sensor.

  4. Short Toxin-like Proteins Abound in Cnidaria Genomes

    Directory of Open Access Journals (Sweden)

    Michal Linial

    2012-11-01

    Full Text Available Cnidaria is a rich phylum that includes thousands of marine species. In this study, we focused on Anthozoa and Hydrozoa that are represented by the Nematostella vectensis (Sea anemone and Hydra magnipapillata genomes. We present a method for ranking the toxin-like candidates from complete proteomes of Cnidaria. Toxin-like functions were revealed using ClanTox, a statistical machine-learning predictor trained on ion channel inhibitors from venomous animals. Fundamental features that were emphasized in training ClanTox include cysteines and their spacing along the sequences. Among the 83,000 proteins derived from Cnidaria representatives, we found 170 candidates that fulfill the properties of toxin-like-proteins, the vast majority of which were previously unrecognized as toxins. An additional 394 short proteins exhibit characteristics of toxin-like proteins at a moderate degree of confidence. Remarkably, only 11% of the predicted toxin-like proteins were previously classified as toxins. Based on our prediction methodology and manual annotation, we inferred functions for over 400 of these proteins. Such functions include protease inhibitors, membrane pore formation, ion channel blockers and metal binding proteins. Many of the proteins belong to small families of paralogs. We conclude that the evolutionary expansion of toxin-like proteins in Cnidaria contributes to their fitness in the complex environment of the aquatic ecosystem.

  5. Structures of pseudechetoxin and pseudecin, two snake-venom cysteine-rich secretory proteins that target cyclic nucleotide-gated ion channels: implications for movement of the C-terminal cysteine-rich domain

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Nobuhiro [Department of Applied Biochemistry, University of Tsukuba, Tsukuba, Ibaraki 305-8572 (Japan); Department of Biochemistry, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki 305-8602 (Japan); Yamazaki, Yasuo [Department of Biochemistry, Meiji Pharmaceutical University, Kiyose, Tokyo 204-8588 (Japan); Brown, R. Lane [Neurological Science Institute, Oregon Health and Science University, Beaverton, Oregon 97006 (United States); Fujimoto, Zui [Department of Biochemistry, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki 305-8602 (Japan); Morita, Takashi, E-mail: tmorita@my-pharm.ac.jp [Department of Biochemistry, Meiji Pharmaceutical University, Kiyose, Tokyo 204-8588 (Japan); Mizuno, Hiroshi, E-mail: tmorita@my-pharm.ac.jp [Department of Biochemistry, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki 305-8602 (Japan); VALWAY Technology Center, NEC Soft Ltd, Koto-ku, Tokyo 136-8627 (Japan); Institute for Biological Resources and Functions, National Institute of Advanced Industrial Science and Technology, Central 6, Tsukuba, Ibaraki 305-8566 (Japan); Department of Applied Biochemistry, University of Tsukuba, Tsukuba, Ibaraki 305-8572 (Japan)

    2008-10-01

    The structures of pseudechetoxin and pseudecin suggest that both proteins bind to cyclic nucleotide-gated ion channels in a manner in which the concave surface occludes the pore entrance. Cyclic nucleotide-gated (CNG) ion channels play pivotal roles in sensory transduction by retinal photoreceptors and olfactory neurons. The elapid snake toxins pseudechetoxin (PsTx) and pseudecin (Pdc) are the only known protein blockers of CNG channels. These toxins belong to a cysteine-rich secretory protein (CRISP) family containing an N-terminal pathogenesis-related proteins of group 1 (PR-1) domain and a C-terminal cysteine-rich domain (CRD). PsTx and Pdc are highly homologous proteins, but their blocking affinities on CNG channels are different: PsTx blocks both the olfactory and retinal channels with ∼15–30-fold higher affinity than Pdc. To gain further insights into their structure and function, the crystal structures of PsTx, Pdc and Zn{sup 2+}-bound Pdc were determined. The structures revealed that most of the amino-acid-residue differences between PsTx and Pdc are located around the concave surface formed between the PR-1 domain and the CRD, suggesting that the concave surface is functionally important for CNG-channel binding and inhibition. A structural comparison in the presence and absence of Zn{sup 2+} ion demonstrated that the concave surface can open and close owing to movement of the CRD upon Zn{sup 2+} binding. The data suggest that PsTx and Pdc occlude the pore entrance and that the dynamic motion of the concave surface facilitates interaction with the CNG channels.

  6. Two polypeptides from Dendroaspis angusticeps venom selectively inhibit the binding of central muscarinic cholinergic receptor ligands.

    Science.gov (United States)

    Jerusalinsky, D; Cerveñasky, C; Peña, C; Raskovsky, S; Dajas, F

    1992-02-01

    Two new polypeptides were isolated and purified from the venom of the snake Dendroaspis angusticeps, which also contains other neuroactive peptides such as Dendrotoxins and Fasciculins. The amino acid composition of the peptides was determined and the first 10 amino acids from the MTX2 N-terminal fragment were sequenced. The so-called muscarinic toxins (MTX1 and MTX2) have been shown to inhibit the specific binding of [3H]QNB (0.15 nM), [3H]PZ (2.5 nM) and [3H]oxoM (2 nM) to bovine cerebral cortex membranes by 60, 88 and 82% respectively. In contrast, they caused only a 30% blockade of the [3H]QNB specific binding to similar membrane preparations from the brainstem. The Hill number for the [3H]PZ binding inhibition by the putative muscarinic toxin MTX2 was 0.95 suggesting homogeneity in the behaviour of the sites involved. The data from [3H]oxoM binding gave a Hill number of 0.83. The decreases in the specific binding involved increases in KD for the three different ligands (8-fold for [3H]QNB, 4-fold for [3H]PZ and 3.5-fold for [3H]oxoM) without significant changes in Bmax, except for a slight decrease in the [3H]oxoM binding sites (-19%); such results suggest that there may be a competitive inhibition between the MTXs and these ligands. The Ki for MTX2/[3H]PZ was 22.58 +/- 3.52 nM; for MTX2/[3H]oxoM, 144.9 +/- 21.07 nM and for MTX2/[3H]QNB, 134.98 +/- 18.35 nM. The labelling of MTX2 with 125I allowed direct demonstration of specific and saturable binding to bovine cerebral cortex synaptosomal membranes. In conclusion, the results reported in this study strongly support the hypotheses that the two polypeptides isolated from D. angusticeps venom selectively inhibit specific ligand binding to central muscarinic receptors, in a competitive manner at least for the antagonist [3H]PZ and that the MTX2 specifically binds to a central site that is suggested to be a muscarinic receptor of the M1 subtype.

  7. Experimental research of specificity of fear of snake: coral snake pattern

    OpenAIRE

    PRŮŠOVÁ, Lucie

    2013-01-01

    Due to shared coevolutionary history of snakes and primates with snakes acting as their main predators, snakes elicit fear in most of the primates, humans included. Humans are able to notice a stimulus that elicits fear, e.g., a snake, much faster. Such ability might have surely positively affected their survival in the past. In the nature, aposematic coloration acts as a warning of a dangerous prey to its predators not to devour it. The highly poisonous American coral snakes have this colora...

  8. Botulinum Toxin Therapy

    Science.gov (United States)

    ... AADA Health System Reform Principles Drug pricing and availability CVS dermatologic formulary restrictions Access to compounded medications ... Botulinum toxin therapy: Overview Also called botulinum rejuvenation Brand names: Botox® Cosmetic, Dysport®, MYOBLOC®, and XEOMIN® When ...

  9. Wallpaper May Breed Toxins

    Science.gov (United States)

    ... https://medlineplus.gov/news/fullstory_166850.html Wallpaper May Breed Toxins: Study Fungus on the walls might ... 2017 FRIDAY, June 23, 2017 (HealthDay News) -- Wallpaper may contribute to "sick building syndrome," a new study ...

  10. Staphylococcus aureus toxins.

    Science.gov (United States)

    Otto, Michael

    2014-02-01

    Staphylococcus aureus is a dangerous pathogen that causes a variety of severe diseases. The virulence of S. aureus is defined by a large repertoire of virulence factors, among which secreted toxins play a preeminent role. Many S. aureus toxins damage biological membranes, leading to cell death. In particular, S. aureus produces potent hemolysins and leukotoxins. Among the latter, some were recently identified to lyse neutrophils after ingestion, representing an especially powerful weapon against bacterial elimination by innate host defense. Furthermore, S. aureus secretes many factors that inhibit the complement cascade or prevent recognition by host defenses. Several further toxins add to this multi-faceted program of S. aureus to evade elimination in the host. This review will give an overview over S. aureus toxins focusing on recent advances in our understanding of how leukotoxins work in receptor-mediated or receptor-independent fashions. Published by Elsevier Ltd.

  11. Snake bioacoustics: toward a richer understanding of the behavioral ecology of snakes.

    Science.gov (United States)

    Young, Bruce A

    2003-09-01

    Snakes are frequently described in both popular and technical literature as either deaf or able to perceive only groundborne vibrations. Physiological studies have shown that snakes are actually most sensitive to airborne vibrations. Snakes are able to detect both airborne and groundborne vibrations using their body surface (termed somatic hearing) as well as from their inner ears. The central auditory pathways for these two modes of "hearing" remain unknown. Recent experimental evidence has shown that snakes can respond behaviorally to both airborne and groundborne vibrations. The ability of snakes to contextualize the sounds and respond with consistent predatory or defensive behaviors suggests that auditory stimuli may play a larger role in the behavioral ecology of snakes than was previously realized. Snakes produce sounds in a variety of ways, and there appear to be multiple acoustic Batesian mimicry complexes among snakes. Analyses of the proclivity for sound production and the acoustics of the sounds produced within a habitat or phylogeny specific context may provide insights into the behavioral ecology of snakes. The relatively low information content in the sounds produced by snakes suggests that these sounds are not suitable for intraspecific communication. Nevertheless, given the diversity of habitats in which snakes are found, and their dual auditory pathways, some form of intraspecific acoustic communication may exist in some species.

  12. Breaking Snake Camouflage: Humans Detect Snakes More Accurately than Other Animals under Less Discernible Visual Conditions.

    Directory of Open Access Journals (Sweden)

    Nobuyuki Kawai

    Full Text Available Humans and non-human primates are extremely sensitive to snakes as exemplified by their ability to detect pictures of snakes more quickly than those of other animals. These findings are consistent with the Snake Detection Theory, which hypothesizes that as predators, snakes were a major source of evolutionary selection that favored expansion of the visual system of primates for rapid snake detection. Many snakes use camouflage to conceal themselves from both prey and their own predators, making it very challenging to detect them. If snakes have acted as a selective pressure on primate visual systems, they should be more easily detected than other animals under difficult visual conditions. Here we tested whether humans discerned images of snakes more accurately than those of non-threatening animals (e.g., birds, cats, or fish under conditions of less perceptual information by presenting a series of degraded images with the Random Image Structure Evolution technique (interpolation of random noise. We find that participants recognize mosaic images of snakes, which were regarded as functionally equivalent to camouflage, more accurately than those of other animals under dissolved conditions. The present study supports the Snake Detection Theory by showing that humans have a visual system that accurately recognizes snakes under less discernible visual conditions.

  13. Breaking Snake Camouflage: Humans Detect Snakes More Accurately than Other Animals under Less Discernible Visual Conditions.

    Science.gov (United States)

    Kawai, Nobuyuki; He, Hongshen

    2016-01-01

    Humans and non-human primates are extremely sensitive to snakes as exemplified by their ability to detect pictures of snakes more quickly than those of other animals. These findings are consistent with the Snake Detection Theory, which hypothesizes that as predators, snakes were a major source of evolutionary selection that favored expansion of the visual system of primates for rapid snake detection. Many snakes use camouflage to conceal themselves from both prey and their own predators, making it very challenging to detect them. If snakes have acted as a selective pressure on primate visual systems, they should be more easily detected than other animals under difficult visual conditions. Here we tested whether humans discerned images of snakes more accurately than those of non-threatening animals (e.g., birds, cats, or fish) under conditions of less perceptual information by presenting a series of degraded images with the Random Image Structure Evolution technique (interpolation of random noise). We find that participants recognize mosaic images of snakes, which were regarded as functionally equivalent to camouflage, more accurately than those of other animals under dissolved conditions. The present study supports the Snake Detection Theory by showing that humans have a visual system that accurately recognizes snakes under less discernible visual conditions.

  14. Fasting for 21days leads to changes in adipose tissue and liver physiology in juvenile checkered garter snakes (Thamnophis marcianus).

    Science.gov (United States)

    Davis, Mary; Jessee, Renee; Close, Matthew; Fu, Xiangping; Settlage, Robert; Wang, Guoqing; Cline, Mark A; Gilbert, Elizabeth R

    2015-12-01

    Snakes often undergo periods of prolonged fasting and, under certain conditions, can survive years without food. Despite this unique phenomenon, there are relatively few reports of the physiological adaptations to fasting in snakes. At post-prandial day 1 (fed) or 21 (fasting), brain, liver, and adipose tissues were collected from juvenile checkered garter snakes (Thamnophis marcianus). There was greater glycerol-3-phosphate dehydrogenase (G3PDH)-specific activity in the liver of fasted than fed snakes (P=0.01). The mRNA abundance of various fat metabolism-associated factors was measured in brain, liver, and adipose tissue. Lipoprotein lipase (LPL) mRNA was greater in fasted than fed snakes in the brain (P=0.04). Adipose triglyceride lipase (ATGL; P=0.006) mRNA was greater in the liver of fasted than fed snakes. In adipose tissue, expression of peroxisome proliferator-activated receptor (PPAR)γ (P=0.01), and fatty acid binding protein 4 (P=0.03) was greater in fed than fasted snakes. Analysis of adipocyte morphology revealed that cross-sectional area (P=0.095) and diameter (P=0.27) were not significantly different between fed and fasted snakes. Results suggest that mean adipocyte area can be preserved during fasting by dampening lipid biosynthesis while not changing rates of lipid hydrolysis. In the liver, however, extensive lipid remodeling may provide energy and lipoproteins to maintain lipid structural integrity during energy restriction. Because the duration of fasting was not sufficient to change adipocyte size, results suggest that the liver is important as a short-term provider of energy in the snake. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. m2-toxin: A selective ligand for M2 muscarinic receptors.

    Science.gov (United States)

    Carsi, J M; Valentine, H H; Potter, L T

    1999-11-01

    Selective ligands are needed for distinguishing the functional roles of M2 receptors in tissues containing several muscarinic receptor subtypes. Because the venom of the green mamba Dendroaspis angusticeps contains the most specific antagonists known for M1 and M4 receptors (m1-toxin and m4-toxin), it was screened for toxins that inhibit the binding of [(3)H]N-methylscopolamine ([(3)H]NMS) to cloned M2 receptors. Desalted venom had as much anti-M2 as anti-M4 activity. The most active anti-M2 toxin in the venom was isolated by gel filtration, cation-exchange chromatography, and reversed-phase HPLC, and called m2-toxin. Spectrometry yielded a mass of 7095 Da, and N-terminal sequencing of 53 amino acids showed RICHSQMSSQPPTTTFCRVNSCYRRTLRDPHDPRGT-IIVRGCGCPRMKPGTKL. This sequence is more homologous to antinicotinic than antimuscarinic toxins, but it lacks three almost invariant residues of antinicotinic toxins required for their activity. m2-Toxin fully blocked the binding of [(3)H]NMS and [(3)H]oxotremorine-M to M2 receptors with Hill coefficients near 1, and blocked 77% of the binding sites for 0.1 nM [(3)H]NMS in the rat brainstem (K(i) = 11 nM). Concentrations that fully blocked cloned M2 receptors had no effect on M4 receptors, but slightly increased [(3)H]NMS binding to M1 receptors, an allosteric effect. In accord with these results, light microscopic autoradiography of the rat brain showed that m2-toxin decreased [(3)H]NMS binding in regions rich in M2 receptors and increased binding in regions rich in M1 receptors. Thus m2-toxin is a novel M2-selective, short-chain neurotoxin that may prove useful for binding and functional studies.

  16. New paradoxical three-finger toxin from the cobra Naja kaouthia venom: Isolation and characterization.

    Science.gov (United States)

    Osipov, A V; Meshcheryakova, A V; Starkov, V G; Ziganshin, R Kh; Oustitch, T L; Peters, L-E; Tsetlin, V I; Utkin, Yu N

    2017-07-01

    A new three-finger toxin nakoroxin was isolated from the cobra Naja kaouthia venom, and its complete amino acid sequence was established. Nakoroxin belongs to the group of "orphan" toxins, data on the biological activity of which are practically absent. Nakoroxin shows no cytotoxicity and does not inhibit the binding of α-bungarotoxin to nicotinic acetylcholine receptors of muscle and α7 types. However, it potentiates the binding of α-bungarotoxin to the acetylcholine-binding protein from Lymnaea stagnalis. This is the first toxin with such an unusual property.

  17. 33 CFR 117.385 - Snake River.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Snake River. 117.385 Section 117.385 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Idaho § 117.385 Snake River. The drawspan of the U.S. 12 bridge...

  18. Coral snake mimicry: does it occur?

    Science.gov (United States)

    Greene, H.W.; McDiarmid, R.W.

    1981-01-01

    Field observations and experimental evidence refute previous objections to the coral snake mimicry hypothesis. Concordant color pattern variation spanning hundreds of miles and several presumed venemous models strongly suggests that several harmless or mildly venemous colubrid snakes are indeed mimics of highly venemous elapids.

  19. Evolutionary stability of sex chromosomes in snakes.

    Science.gov (United States)

    Rovatsos, Michail; Vukić, Jasna; Lymberakis, Petros; Kratochvíl, Lukáš

    2015-12-22

    Amniote vertebrates possess various mechanisms of sex determination, but their variability is not equally distributed. The large evolutionary stability of sex chromosomes in viviparous mammals and birds was believed to be connected with their endothermy. However, some ectotherm lineages seem to be comparably conserved in sex determination, but previously there was a lack of molecular evidence to confirm this. Here, we document a stability of sex chromosomes in advanced snakes based on the testing of Z-specificity of genes using quantitative PCR (qPCR) across 37 snake species (our qPCR technique is suitable for molecular sexing in potentially all advanced snakes). We discovered that at least part of sex chromosomes is homologous across all families of caenophidian snakes (Acrochordidae, Xenodermatidae, Pareatidae, Viperidae, Homalopsidae, Colubridae, Elapidae and Lamprophiidae). The emergence of differentiated sex chromosomes can be dated back to about 60 Ma and preceded the extensive diversification of advanced snakes, the group with more than 3000 species. The Z-specific genes of caenophidian snakes are (pseudo)autosomal in the members of the snake families Pythonidae, Xenopeltidae, Boidae, Erycidae and Sanziniidae, as well as in outgroups with differentiated sex chromosomes such as monitor lizards, iguanas and chameleons. Along with iguanas, advanced snakes are therefore another example of ectothermic amniotes with a long-term stability of sex chromosomes comparable with endotherms. © 2015 The Author(s).

  20. Snake venom instability | Willemse | African Zoology

    African Journals Online (AJOL)

    Egyptian cobra Naja haje haje) and puffadder (Bills arietans). Considerable differences in electrophoretic characteristics were found between fresh venom and commercial venom samples from the same species of snake. These differences could be attributed partly to the instability of snake venom under conditions of drying ...

  1. On a collection of Snakes from Dehli

    NARCIS (Netherlands)

    Lidth de Jeude, van Th.W.

    1890-01-01

    During his stay in Laboean (Delili, East-Sumatra) Dr. B. Hagen, to whom the Leyden Museum is indebted for large series of mammals, birds and insects, also collected a large number of snakes, the greater part of which were sent to our Museum. Dr. Hagen took a lively interest in snakes, and being

  2. Anti-idiotypic antibodies that protect cells against the action of diphtheria toxin

    Energy Technology Data Exchange (ETDEWEB)

    Rolf, J.M.; Gaudin, H.M.; Tirrell, S.M.; MacDonald, A.B.; Eidels, L.

    1989-03-01

    An anti-idiotypic serum prepared against the combining site (idiotype) of specific anti-diphtheria toxoid antibodies was characterized with respect to its interaction with highly diphtheria toxin-sensitive Vero cells. Although the anti-idiotypic serum protected Vero cells against the cytotoxic action of diphtheria toxin, it did not prevent the binding of /sup 125/I-labeled diphtheria toxin to the cells but did inhibit the internalization and degradation of /sup 125/I-labeled toxin. This anti-idiotypic serum immunoprecipitated a cell-surface protein from radiolabeled Vero cells with an apparent Mr of approximately 15,000. These results are consistent with the hypothesis that the anti-idiotypic serum contains antibodies that carry an internal image of an internalization site on the toxin and that a cell-surface protein involved in toxin internalization possesses a complementary site recognized by both the toxin and the anti-idiotypic antibodies.

  3. High-throughput immuno-profiling of mamba (Dendroaspis) venom toxin epitopes using high-density peptide microarrays

    DEFF Research Database (Denmark)

    Engmark, Mikael; Andersen, Mikael Rørdam; Laustsen, Andreas Hougaard

    2016-01-01

    Snakebite envenoming is a serious condition requiring medical attention and administration of antivenom. Current antivenoms are antibody preparations obtained from the plasma of animals immunised with whole venom(s) and contain antibodies against snake venom toxins, but also against other antigen...

  4. Comparative in vitro and in vivo assessment of toxin neutralization by anti-tetanus toxin monoclonal antibodies

    Science.gov (United States)

    Yousefi, Mehdi; Khosravi-Eghbal, Roya; Reza Mahmoudi, Ahmad; Jeddi-Tehrani, Mahmood; Rabbani, Hodjatallah; Shokri, Fazel

    2014-01-01

    Tetanus is caused by the tetanus neurotoxin (TeNT), a 150 kDa single polypeptide molecule which is cleaved into an active two-chain molecule composed of a 50 kDa N-terminal light (L) and a 100 kDa C-terminal heavy (H) chains. Recently, extensive effort has focused on characterization of TeNT binding receptors and toxin neutralization by monoclonal antibodies (mAbs). Toxin binding inhibition and neutralization is routinely assessed either in vitro by the ganglioside GT1b binding inhibition assay or in vivo using an animal model. These two assay systems have never been compared. In the present study, we report characterization of eleven mAbs against different parts of TeNT. The toxin inhibitory and neutralization activity of the mAbs was assessed in vitro and in vivo respectively. Our data demonstrated that seven mAbs bind to fragment C of the heavy chain, two mAbs react with the light chain, one mAb recognizes both chains and one mAb reacts with neither light chain nor fragment C. Six fragment C specific mAbs were able to inhibit TeNT binding to GT1b ganglioside in vitro but three failed to neutralize the toxin in vivo. One in vitro inhibitory mAb (1F3E3) was found to synergize with the in vivo neutralizing mAbs to reduce toxin lethal activity in vivo. Sequencing of the immunoglobulin heavy and light chain variable region genes revealed that the three in vivo neutralizing mAbs were derived from a common origin. Altogether, our data suggests that fragment C specific mAbs contribute to toxin neutralization in both systems, though some of the GT1b binding inhibitory mAbs may not be able to neutralize TeNT in vivo. PMID:24126015

  5. Snake and staff symbolism, and healing | Retief | South African ...

    African Journals Online (AJOL)

    Since time immemorial the snake has been venerated as an enigmatic creature with supernatural powers. As a snake and staff symbol it is also traditionally associated with the healing arts, either as the single-snake emblem of Asklepios, or as the double-snake emblem (caduceus) of Hermes. The mythological basis for this ...

  6. 27 CFR 9.208 - Snake River Valley.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Snake River Valley. 9.208... Snake River Valley. (a) Name. The name of the viticultural area described in this section is “Snake River Valley”. For purposes of part 4 of this chapter, “Snake River Valley” is a term of viticultural...

  7. 77 FR 10960 - Drawbridge Operation Regulation; Snake Creek, Islamorada, FL

    Science.gov (United States)

    2012-02-24

    ... SECURITY Coast Guard 33 CFR Part 117 Drawbridge Operation Regulation; Snake Creek, Islamorada, FL AGENCY... of Snake Creek Bridge, mile 0.5, across Snake Creek, in Islamorada, Florida. The regulation is set... Sheriff's Office has requested a temporary modification to the operating schedule of Snake Creek Bridge in...

  8. Epidemiology of Snake Bites among Selected Communities in the ...

    African Journals Online (AJOL)

    Snake is one of the major group of games feared by people in many localities because of their venoms, yet snakes are equally afraid of human beings. This balance of terror apart from affecting both man and snakes has also led to their deaths. Epidemiology of snake bites among selected communities in the enclave of ...

  9. Structural Insights into Clostridium perfringens Delta Toxin Pore Formation.

    Directory of Open Access Journals (Sweden)

    Jessica Huyet

    Full Text Available Clostridium perfringens Delta toxin is one of the three hemolysin-like proteins produced by C. perfringens type C and possibly type B strains. One of the others, NetB, has been shown to be the major cause of Avian Nectrotic Enteritis, which following the reduction in use of antibiotics as growth promoters, has become an emerging disease of industrial poultry. Delta toxin itself is cytotoxic to the wide range of human and animal macrophages and platelets that present GM2 ganglioside on their membranes. It has sequence similarity with Staphylococcus aureus β-pore forming toxins and is expected to heptamerize and form pores in the lipid bilayer of host cell membranes. Nevertheless, its exact mode of action remains undetermined. Here we report the 2.4 Å crystal structure of monomeric Delta toxin. The superposition of this structure with the structure of the phospholipid-bound F component of S. aureus leucocidin (LukF revealed that the glycerol molecules bound to Delta toxin and the phospholipids in LukF are accommodated in the same hydrophobic clefts, corresponding to where the toxin is expected to latch onto the membrane, though the binding sites show significant differences. From structure-based sequence alignment with the known structure of staphylococcal α-hemolysin, a model of the Delta toxin pore form has been built. Using electron microscopy, we have validated our model and characterized the Delta toxin pore on liposomes. These results highlight both similarities and differences in the mechanism of Delta toxin (and by extension NetB cytotoxicity from that of the staphylococcal pore-forming toxins.

  10. Cholera- and anthrax-like toxins are among several new ADP-ribosyltransferases.

    Directory of Open Access Journals (Sweden)

    Robert J Fieldhouse

    Full Text Available Chelt, a cholera-like toxin from Vibrio cholerae, and Certhrax, an anthrax-like toxin from Bacillus cereus, are among six new bacterial protein toxins we identified and characterized using in silico and cell-based techniques. We also uncovered medically relevant toxins from Mycobacterium avium and Enterococcus faecalis. We found agriculturally relevant toxins in Photorhabdus luminescens and Vibrio splendidus. These toxins belong to the ADP-ribosyltransferase family that has conserved structure despite low sequence identity. Therefore, our search for new toxins combined fold recognition with rules for filtering sequences--including a primary sequence pattern--to reduce reliance on sequence identity and identify toxins using structure. We used computers to build models and analyzed each new toxin to understand features including: structure, secretion, cell entry, activation, NAD+ substrate binding, intracellular target binding and the reaction mechanism. We confirmed activity using a yeast growth test. In this era where an expanding protein structure library complements abundant protein sequence data--and we need high-throughput validation--our approach provides insight into the newest toxin ADP-ribosyltransferases.

  11. Inhibition of nicotinic acetylcholine receptors, a novel facet in the pleiotropic activities of snake venom phospholipases A2.

    Directory of Open Access Journals (Sweden)

    Catherine A Vulfius

    Full Text Available Phospholipases A2 represent the most abundant family of snake venom proteins. They manifest an array of biological activities, which is constantly expanding. We have recently shown that a protein bitanarin, isolated from the venom of the puff adder Bitis arietans and possessing high phospholipolytic activity, interacts with different types of nicotinic acetylcholine receptors and with the acetylcholine-binding protein. To check if this property is characteristic to all venom phospholipases A2, we have studied the capability of these enzymes from other snakes to block the responses of Lymnaea stagnalis neurons to acetylcholine or cytisine and to inhibit α-bungarotoxin binding to nicotinic acetylcholine receptors and acetylcholine-binding proteins. Here we present the evidence that phospholipases A2 from venoms of vipers Vipera ursinii and V. nikolskii, cobra Naja kaouthia, and krait Bungarus fasciatus from different snake families suppress the acetylcholine- or cytisine-elicited currents in L. stagnalis neurons and compete with α-bungarotoxin for binding to muscle- and neuronal α7-types of nicotinic acetylcholine receptor, as well as to acetylcholine-binding proteins. As the phospholipase A2 content in venoms is quite high, under some conditions the activity found may contribute to the deleterious venom effects. The results obtained suggest that the ability to interact with nicotinic acetylcholine receptors may be a general property of snake venom phospholipases A2, which add a new target to the numerous activities of these enzymes.

  12. [Molecular mechanism of action of tetanus toxin and botulinum neurotoxins].

    Science.gov (United States)

    Poulain, B

    1994-02-01

    Tetanus toxin and botulinum neurotoxins are di-chain proteins of 150 kD molecular weight. They are produced by bacteria of the Clostridium genus. These toxins act on the nervous system by inhibiting neurotransmitter release (glycine and GABA in the case of tetanus toxin; acetylcholine in the case of botulinum neurotoxins) thus inducing the spastic or flaccid paralysis that characterizes tetanus and botulism, respectively. Their cellular mechanism of action involves three main steps, namely binding to the neurone membrane, internalization and intracellular blockade of the release mechanism for neurotransmitters. Membrane acceptors for these toxins are not yet fully identified; they would consist of membrane gangliosides and proteins. The internalization step would be achieved by endocytosis. Recent findings show that both binding and internalization are mediated only by the heavy chain of the toxins whereas the intracellular blockade of neurotransmitter release involves their light chain alone. The light chain has been identified as a zinc metalloprotease and its substrates would be proteins involved in the neurotransmitter release mechanism. The target of tetanus toxin and of botulinum neurotoxin type B is VAMP/synaptobrevin, a membrane protein of the synaptic vesicles of nerve cell terminals.

  13. 50 CFR Table 3 to Part 226 - Hydrologic Units Containing Critical Habitat for Snake River Sockeye Salmon and Snake River...

    Science.gov (United States)

    2010-10-01

    ... Habitat for Snake River Sockeye Salmon and Snake River Spring/Summer and Fall Chinook Salmon 3 Table 3 to... Part 226—Hydrologic Units Containing Critical Habitat for Snake River Sockeye Salmon and Snake River... Snake—Asotin 17060103 17060103 17060103 Upper Grande Ronde 17060104 Wallowa 17060105 Lower Grande Ronde...

  14. Functional variability of snake venom metalloproteinases: adaptive advantages in targeting different prey and implications for human envenomation.

    Science.gov (United States)

    Bernardoni, Juliana L; Sousa, Leijiane F; Wermelinger, Luciana S; Lopes, Aline S; Prezoto, Benedito C; Serrano, Solange M T; Zingali, Russolina B; Moura-da-Silva, Ana M

    2014-01-01

    Snake venom metalloproteinases (SVMPs) are major components in most viperid venoms that induce disturbances in the hemostatic system and tissues of animals envenomated by snakes. These disturbances are involved in human pathology of snake bites and appear to be essential for the capture and digestion of snake's prey and avoidance of predators. SVMPs are a versatile family of venom toxins acting on different hemostatic targets which are present in venoms in distinct structural forms. However, the reason why a large number of different SVMPs are expressed in some venoms is still unclear. In this study, we evaluated the interference of five isolated SVMPs in blood coagulation of humans, birds and small rodents. P-III class SVMPs (fractions Ic, IIb and IIc) possess gelatinolytic and hemorrhagic activities, and, of these, two also show fibrinolytic activity. P-I class SVMPs (fractions IVa and IVb) are only fibrinolytic. P-III class SVMPs reduced clotting time of human plasma. Fraction IIc was characterized as prothrombin activator and fraction Ic as factor X activator. In the absence of Ca2+, a firm clot was observed in chicken blood samples with fractions Ic, IIb and partially with fraction IIc. In contrast, without Ca2+, only fraction IIc was able to induce a firm clot in rat blood. In conclusion, functionally distinct forms of SVMPs were found in B. neuwiedi venom that affect distinct mechanisms in the coagulation system of humans, birds and small rodents. Distinct SVMPs appear to be more specialized to rat or chicken blood, strengthening the current hypothesis that toxin diversity enhances the possibilities of the snakes for hunting different prey or evading different predators. This functional diversity also impacts the complexity of human envenoming since different hemostatic mechanisms will be targeted by SVMPs accounting for the complexity of the response of humans to venoms.

  15. Functional variability of snake venom metalloproteinases: adaptive advantages in targeting different prey and implications for human envenomation.

    Directory of Open Access Journals (Sweden)

    Juliana L Bernardoni

    Full Text Available Snake venom metalloproteinases (SVMPs are major components in most viperid venoms that induce disturbances in the hemostatic system and tissues of animals envenomated by snakes. These disturbances are involved in human pathology of snake bites and appear to be essential for the capture and digestion of snake's prey and avoidance of predators. SVMPs are a versatile family of venom toxins acting on different hemostatic targets which are present in venoms in distinct structural forms. However, the reason why a large number of different SVMPs are expressed in some venoms is still unclear. In this study, we evaluated the interference of five isolated SVMPs in blood coagulation of humans, birds and small rodents. P-III class SVMPs (fractions Ic, IIb and IIc possess gelatinolytic and hemorrhagic activities, and, of these, two also show fibrinolytic activity. P-I class SVMPs (fractions IVa and IVb are only fibrinolytic. P-III class SVMPs reduced clotting time of human plasma. Fraction IIc was characterized as prothrombin activator and fraction Ic as factor X activator. In the absence of Ca2+, a firm clot was observed in chicken blood samples with fractions Ic, IIb and partially with fraction IIc. In contrast, without Ca2+, only fraction IIc was able to induce a firm clot in rat blood. In conclusion, functionally distinct forms of SVMPs were found in B. neuwiedi venom that affect distinct mechanisms in the coagulation system of humans, birds and small rodents. Distinct SVMPs appear to be more specialized to rat or chicken blood, strengthening the current hypothesis that toxin diversity enhances the possibilities of the snakes for hunting different prey or evading different predators. This functional diversity also impacts the complexity of human envenoming since different hemostatic mechanisms will be targeted by SVMPs accounting for the complexity of the response of humans to venoms.

  16. Botulinum Toxin (Botox) for Facial Wrinkles

    Science.gov (United States)

    ... Eye Health / Eye Health A-Z Botulinum Toxin (Botox) for Facial Wrinkles Sections Botulinum Toxin (Botox) for ... How Does Botulinum Toxin (Botox) Work? Botulinum Toxin (Botox) for Facial Wrinkles Leer en Español: La toxina ...

  17. Novel Structure and Function of Typhoid Toxin

    Science.gov (United States)

    ... Matters NIH Research Matters July 29, 2013 Novel Structure and Function of Typhoid Toxin Structure of typhoid toxin, showing the 2 A subunits ( ... to cultured cells. The scientists next determined the structure of the typhoid toxin. The toxin was already ...

  18. Cholera toxin entry into pig enterocytes occurs via a lipid raft- and clathrin-dependent mechanism

    DEFF Research Database (Denmark)

    Hansen, Gert H; Dalskov, Stine-Mathilde; Rasmussen, Christina Rehné

    2005-01-01

    The small intestinal brush border is composed of lipid raft microdomains, but little is known about their role in the mechanism whereby cholera toxin gains entry into the enterocyte. The present work characterized the binding of cholera toxin B subunit (CTB) to the brush border and its...

  19. STUDY OF CLINICAL MANIFESTATIONS AND COMPLICATIONS OF HAEMOTOXIC SNAKE ENVENOMATION

    OpenAIRE

    Narasimham; Srinivasa Rao

    2015-01-01

    BACKGROUND AND OBJECTIVES: Snake bites are of major public health importance in many communities as causes of haemorrhage, other morbidity and mortality. 1 Of the 3000 species of snakes, about 500 belong to the 3 families of venomous snakes, Atr actaspididae, Elapidae and Viperidae. Estimated 15000 – 20000 people die each year from snake bite in India. 2 In tropical countries snake bite is occupational disease of farmers, plantation workers and hunters. In ...

  20. Head triangulation as anti-predatory mechanism in snakes

    OpenAIRE

    Dell'Aglio,Denise Dalbosco; Toma,Tiago Shizen Pacheco; Muelbert, Adriane Esquivel; Sacco, Anne Gomes; Tozetti,Alexandro Marques

    2012-01-01

    Anti-predator mechanisms in snakes are diverse and complex, including mimetic behavior. Some snakes triangulate their head, probably mimicking other more dangerous snakes. However, there is a lack of studies that demonstrate the effectiveness of this behavior with natural predators. The aim of this study was to verify, using artificial snakes, if snakes with triangular heads are less susceptible to attack by predators, and if predatory attack is targeted to the head of serpents. Artificial sn...

  1. The Biology of the Cytolethal Distending Toxins

    Directory of Open Access Journals (Sweden)

    Teresa Frisan

    2011-03-01

    Full Text Available The cytolethal distending toxins (CDTs, produced by a variety of Gram-negative pathogenic bacteria, are the first bacterial genotoxins described, since they cause DNA damage in the target cells. CDT is an A-B2 toxin, where the CdtA and CdtC subunits are required to mediate the binding on the surface of the target cells, allowing internalization of the active CdtB subunit, which is functionally homologous to the mammalian deoxyribonuclease I. The nature of the surface receptor is still poorly characterized, however binding of CDT requires intact lipid rafts, and its internalization occurs via dynamin-dependent endocytosis. The toxin is retrograde transported through the Golgi complex and the endoplasmic reticulum, and subsequently translocated into the nuclear compartment, where it exerts the toxic activity. Cellular intoxication induces DNA damage and activation of the DNA damage responses, which results in arrest of the target cells in the G1 and/or G2 phases of the cell cycle and activation of DNA repair mechanisms. Cells that fail to repair the damage will senesce or undergo apoptosis. This review will focus on the well-characterized aspects of the CDT biology and discuss the questions that still remain unanswered.

  2. Many roads to resistance: how invertebrates adapt to Bt toxins.

    Science.gov (United States)

    Griffitts, Joel S; Aroian, Raffi V

    2005-06-01

    The Cry family of Bacillus thuringiensis insecticidal and nematicidal proteins constitutes a valuable source of environmentally benign compounds for the control of insect pests and disease agents. An understanding of Cry toxin resistance at a molecular level will be critical to the long-term utility of this technology; it may also shed light on basic mechanisms used by other bacterial toxins that target specific organisms or cell types. Selection and cross-resistance studies have confirmed that genetic adaptation can elicit varying patterns of Cry toxin resistance, which has been associated with deficient protoxin activation by host proteases, and defective Cry toxin-binding cell surface molecules, such as cadherins, aminopeptidases and glycolipids. Recent work also suggests Cry toxin resistance may be induced in invertebrates as an active immune response. The use of model invertebrates, such as Caenorhabditis elegans and Drosophila melanogaster, as well as advances in insect genomics, are likely to accelerate efforts to clone Cry toxin resistance genes and come to a detailed and broad understanding of Cry toxin resistance.

  3. Structural Insights into Bacillus thuringiensis Cry, Cyt and Parasporin Toxins

    Science.gov (United States)

    Xu, Chengchen; Wang, Bi-Cheng; Yu, Ziniu; Sun, Ming

    2014-01-01

    Since the first X-ray structure of Cry3Aa was revealed in 1991, numerous structures of B. thuringiensis toxins have been determined and published. In recent years, functional studies on the mode of action and resistance mechanism have been proposed, which notably promoted the developments of biological insecticides and insect-resistant transgenic crops. With the exploration of known pore-forming toxins (PFTs) structures, similarities between PFTs and B. thuringiensis toxins have provided great insights into receptor binding interactions and conformational changes from water-soluble to membrane pore-forming state of B. thuringiensis toxins. This review mainly focuses on the latest discoveries of the toxin working mechanism, with the emphasis on structural related progress. Based on the structural features, B. thuringiensis Cry, Cyt and parasporin toxins could be divided into three categories: three-domain type α-PFTs, Cyt toxin type β-PFTs and aerolysin type β-PFTs. Structures from each group are elucidated and discussed in relation to the latest data, respectively. PMID:25229189

  4. Marine Toxins: An Overview

    Science.gov (United States)

    Fusetani, Nobuhiro

    Oceans provide enormous and diverse space for marine life. Invertebrates are conspicuous inhabitants in certain zones such as the intertidal; many are soft-bodied, relatively immobile and lack obvious physical defenses. These animals frequently have evolved chemical defenses against predators and overgrowth by fouling organisms. Marine animals may accumulate and use a variety of toxins from prey organisms and from symbiotic microorganisms for their own purposes. Thus, toxic animals are particularly abundant in the oceans. The toxins vary from small molecules to high molecular weight proteins and display unique chemical and biological features of scientific interest. Many of these substances can serve as useful research tools or molecular models for the design of new drugs and pesticides. This chapter provides an initial survey of these toxins and their salient properties.

  5. Marine and freshwater toxins.

    Science.gov (United States)

    Hungerford, James M

    2006-01-01

    In a very busy and exciting year, 2005 included First Action approval of a much needed official method for paralytic shellfish toxins and multiple international toxin symposia highlighted by groundbreaking research. These are the first-year milestones and activities of the Marine and Freshwater Toxins Task Force and Analytical Community. Inaugurated in 2004 and described in detail in last year's General Referee Report (1) this international toxins group has grown to 150 members from many regions and countries. Perhaps most important they are now making important and global contributions to food safety and to providing alternatives to animal-based assays. Official Method 2005.06 was first approved in late 2004 by the Task Force and subsequently Official First Action in 2005 (2) by the Methods Committee on Natural Toxins and Food Allergens and the Official Methods Board. This nonproprietary method (3) is a precolumn oxidation, liquid chromatographic method that makes good use of fluorescence detection to provide high sensitivity detection of the saxitoxins. It has also proven to be rugged enough for regulatory use and the highest level of validation. As pointed out in the report of method principle investigator and Study Director James Lawrence, approval of 2005.06 now provides the first official alternative to the mouse bioassay after many decades of shellfish monitoring. This past year in April 2005 the group also held their first international conference, "Marine and Freshwater Toxins Analysis: Ist Joint Symposium and AOAC Task Force Meeting," in Baiona, Spain. The 4-day conference consisted of research and stakeholder presentations and symposium-integrated subgroup sessions on ciguatoxins, saxitoxin assays and liquid chromatography (LC) methods for saxitoxins and domoic acids, okadaiates and azaspiracids, and yessotoxins. Many of these subgroups were recently formed in 2005 and are working towards their goals of producing officially validated analytical methods

  6. Secreted Phospholipases A2 of Snake Venoms: Effects on the Peripheral Neuromuscular System with Comments on the Role of Phospholipases A2 in Disorders of the CNS and Their Uses in Industry

    Directory of Open Access Journals (Sweden)

    John B. Harris

    2013-12-01

    Full Text Available Neuro- and myotoxicological signs and symptoms are significant clinical features of envenoming snakebites in many parts of the world. The toxins primarily responsible for the neuro and myotoxicity fall into one of two categories—those that bind to and block the post-synaptic acetylcholine receptors (AChR at the neuromuscular junction and neurotoxic phospholipases A2 (PLAs that bind to and hydrolyse membrane phospholipids of the motor nerve terminal (and, in most cases, the plasma membrane of skeletal muscle to cause degeneration of the nerve terminal and skeletal muscle. This review provides an introduction to the biochemical properties of secreted sPLA2s in the venoms of many dangerous snakes and a detailed discussion of their role in the initiation of the neurologically important consequences of snakebite. The rationale behind the experimental studies on the pharmacology and toxicology of the venoms and isolated PLAs in the venoms is discussed, with particular reference to the way these studies allow one to understand the biological basis of the clinical syndrome. The review also introduces the involvement of PLAs in inflammatory and degenerative disorders of the central nervous system (CNS and their commercial use in the food industry. It concludes with an introduction to the problems associated with the use of antivenoms in the treatment of neuro-myotoxic snakebite and the search for alternative treatments.

  7. Secreted phospholipases A2 of snake venoms: effects on the peripheral neuromuscular system with comments on the role of phospholipases A2 in disorders of the CNS and their uses in industry.

    Science.gov (United States)

    Harris, John B; Scott-Davey, Tracey

    2013-12-17

    Neuro- and myotoxicological signs and symptoms are significant clinical features of envenoming snakebites in many parts of the world. The toxins primarily responsible for the neuro and myotoxicity fall into one of two categories--those that bind to and block the post-synaptic acetylcholine receptors (AChR) at the neuromuscular junction and neurotoxic phospholipases A2 (PLAs) that bind to and hydrolyse membrane phospholipids of the motor nerve terminal (and, in most cases, the plasma membrane of skeletal muscle) to cause degeneration of the nerve terminal and skeletal muscle. This review provides an introduction to the biochemical properties of secreted sPLA2s in the venoms of many dangerous snakes and a detailed discussion of their role in the initiation of the neurologically important consequences of snakebite. The rationale behind the experimental studies on the pharmacology and toxicology of the venoms and isolated PLAs in the venoms is discussed, with particular reference to the way these studies allow one to understand the biological basis of the clinical syndrome. The review also introduces the involvement of PLAs in inflammatory and degenerative disorders of the central nervous system (CNS) and their commercial use in the food industry. It concludes with an introduction to the problems associated with the use of antivenoms in the treatment of neuro-myotoxic snakebite and the search for alternative treatments.

  8. Mosquitocidal bacterial toxins: diversity, mode of action and resistance phenomena

    Directory of Open Access Journals (Sweden)

    Charles Jean-François

    2000-01-01

    Full Text Available Bacteria active against dipteran larvae (mosquitoes and black flies include a wide variety of Bacillus thuringiensis and B. sphaericus strains, as well as isolates of Brevibacillus laterosporus and Clostridium bifermentans. All display different spectra and levels of activity correlated with the nature of the toxins, mainly produced during the sporulation process. This paper describes the structure and mode of action of the main mosquitocidal toxins, in relationship with their potential use in mosquito and/or black fly larvae control. Investigations with laboratory and field colonies of mosquitoes that have become highly resistant to the B. sphaericus Bin toxin have shown that several mechanisms of resistance are involved, some affecting the toxin/receptor binding step, others unknown.

  9. Sea snakes rarely venture far from home.

    Science.gov (United States)

    Lukoschek, Vimoksalehi; Shine, Richard

    2012-06-01

    The extent to which populations are connected by dispersal influences all aspects of their biology and informs the spatial scale of optimal conservation strategies. Obtaining direct estimates of dispersal is challenging, particularly in marine systems, with studies typically relying on indirect approaches to evaluate connectivity. To overcome this challenge, we combine information from an eight-year mark-recapture study with high-resolution genetic data to demonstrate extremely low dispersal and restricted gene flow at small spatial scales for a large, potentially mobile marine vertebrate, the turtleheaded sea snake (Emydocephalus annulatus). Our mark-recapture study indicated that adjacent bays in New Caledonia (snake populations. Sea snakes could easily swim between bays but rarely do so. Of 817 recaptures of marked snakes, only two snakes had moved between bays. We genotyped 136 snakes for 11 polymorphic microsatellite loci and found statistically significant genetic divergence between the two bays (F(ST)= 0.008, P snakes rarely venture far from home, which has strong implications for their ecology, evolution, and conservation.

  10. Coral snakes predict the evolution of mimicry across New World snakes.

    Science.gov (United States)

    Davis Rabosky, Alison R; Cox, Christian L; Rabosky, Daniel L; Title, Pascal O; Holmes, Iris A; Feldman, Anat; McGuire, Jimmy A

    2016-05-05

    Batesian mimicry, in which harmless species (mimics) deter predators by deceitfully imitating the warning signals of noxious species (models), generates striking cases of phenotypic convergence that are classic examples of evolution by natural selection. However, mimicry of venomous coral snakes has remained controversial because of unresolved conflict between the predictions of mimicry theory and empirical patterns in the distribution and abundance of snakes. Here we integrate distributional, phenotypic and phylogenetic data across all New World snake species to demonstrate that shifts to mimetic coloration in nonvenomous snakes are highly correlated with coral snakes in both space and time, providing overwhelming support for Batesian mimicry. We also find that bidirectional transitions between mimetic and cryptic coloration are unexpectedly frequent over both long- and short-time scales, challenging traditional views of mimicry as a stable evolutionary 'end point' and suggesting that insect and snake mimicry may have different evolutionary dynamics.

  11. Coral snakes predict the evolution of mimicry across New World snakes

    Science.gov (United States)

    Davis Rabosky, Alison R.; Cox, Christian L.; Rabosky, Daniel L.; Title, Pascal O.; Holmes, Iris A.; Feldman, Anat; McGuire, Jimmy A.

    2016-01-01

    Batesian mimicry, in which harmless species (mimics) deter predators by deceitfully imitating the warning signals of noxious species (models), generates striking cases of phenotypic convergence that are classic examples of evolution by natural selection. However, mimicry of venomous coral snakes has remained controversial because of unresolved conflict between the predictions of mimicry theory and empirical patterns in the distribution and abundance of snakes. Here we integrate distributional, phenotypic and phylogenetic data across all New World snake species to demonstrate that shifts to mimetic coloration in nonvenomous snakes are highly correlated with coral snakes in both space and time, providing overwhelming support for Batesian mimicry. We also find that bidirectional transitions between mimetic and cryptic coloration are unexpectedly frequent over both long- and short-time scales, challenging traditional views of mimicry as a stable evolutionary ‘end point' and suggesting that insect and snake mimicry may have different evolutionary dynamics. PMID:27146100

  12. Characterization of rabbit ileal receptors for Clostridium difficile toxin A. Evidence for a receptor-coupled G protein

    Energy Technology Data Exchange (ETDEWEB)

    Pothoulakis, C.; LaMont, J.T.; Eglow, R.; Gao, N.; Rubins, J.B.; Theoharides, T.C.; Dickey, B.F. (Boston Univ. School of Medicine, MA (USA))

    1991-07-01

    The purpose of this study was to characterize the surface receptor for toxin A, the enterotoxin from Clostridium difficile, on rabbit intestinal brush borders (BB) and on rat basophilic leukemia (RBL) cells. Purified toxin A was radiolabeled using a modified Bolton-Hunter method to sp act 2 microCi/micrograms, with retention of full biologic activity. 3H-Toxin A bound specifically to a single class of receptors on rabbit BB and on RBL cells with dissociation constants of 5.4 x 10(-8) and 3.5 x 10(-8) M, respectively. RBL cells were highly sensitive to toxin A (cell rounding) and had 180,000 specific binding sites per cell, whereas IMR-90 fibroblasts were far less sensitive to toxin A and lacked detectable specific binding sites. Exposure of BB to trypsin or chymotrypsin significantly reduced 3H-toxin A specific binding. Preincubation of BB with Bandeirea simplicifolia (BS-1) lectin also reduced specific binding, and CHAPS-solubilized receptors could be immobilized with WGA-agarose. The addition of 100 nM toxin A accelerated the association of 35S-GTP gamma S with rabbit ileal BB, and preincubation of BB with the GTP analogues GTP gamma S or Gpp(NH)p, significantly reduced 3H-toxin A specific binding. Our data indicate that the membrane receptor for toxin A is a galactose and N-acetyl-glucosamine-containing glycoprotein which appears to be coupled to a G protein.

  13. The Hidden Snake in the Grass: Superior Detection of Snakes in Challenging Attentional Conditions.

    Directory of Open Access Journals (Sweden)

    Sandra C Soares

    Full Text Available Snakes have provided a serious threat to primates throughout evolution. Furthermore, bites by venomous snakes still cause significant morbidity and mortality in tropical regions of the world. According to the Snake Detection Theory (SDT Isbell, 2006; 2009, the vital need to detect camouflaged snakes provided strong evolutionary pressure to develop astute perceptual capacity in animals that were potential targets for snake attacks. We performed a series of behavioral tests that assessed snake detection under conditions that may have been critical for survival. We used spiders as the control stimulus because they are also a common object of phobias and rated negatively by the general population, thus commonly lumped together with snakes as "evolutionary fear-relevant". Across four experiments (N = 205 we demonstrate an advantage in snake detection, which was particularly obvious under visual conditions known to impede detection of a wide array of common stimuli, for example brief stimulus exposures, stimuli presentation in the visual periphery, and stimuli camouflaged in a cluttered environment. Our results demonstrate a striking independence of snake detection from ecological factors that impede the detection of other stimuli, which suggests that, consistent with the SDT, they reflect a specific biological adaptation. Nonetheless, the empirical tests we report are limited to only one aspect of this rich theory, which integrates findings across a wide array of scientific disciplines.

  14. The Hidden Snake in the Grass: Superior Detection of Snakes in Challenging Attentional Conditions.

    Science.gov (United States)

    Soares, Sandra C; Lindström, Björn; Esteves, Francisco; Ohman, Arne

    2014-01-01

    Snakes have provided a serious threat to primates throughout evolution. Furthermore, bites by venomous snakes still cause significant morbidity and mortality in tropical regions of the world. According to the Snake Detection Theory (SDT Isbell, 2006; 2009), the vital need to detect camouflaged snakes provided strong evolutionary pressure to develop astute perceptual capacity in animals that were potential targets for snake attacks. We performed a series of behavioral tests that assessed snake detection under conditions that may have been critical for survival. We used spiders as the control stimulus because they are also a common object of phobias and rated negatively by the general population, thus commonly lumped together with snakes as "evolutionary fear-relevant". Across four experiments (N = 205) we demonstrate an advantage in snake detection, which was particularly obvious under visual conditions known to impede detection of a wide array of common stimuli, for example brief stimulus exposures, stimuli presentation in the visual periphery, and stimuli camouflaged in a cluttered environment. Our results demonstrate a striking independence of snake detection from ecological factors that impede the detection of other stimuli, which suggests that, consistent with the SDT, they reflect a specific biological adaptation. Nonetheless, the empirical tests we report are limited to only one aspect of this rich theory, which integrates findings across a wide array of scientific disciplines.

  15. The Hidden Snake in the Grass: Superior Detection of Snakes in Challenging Attentional Conditions

    Science.gov (United States)

    Soares, Sandra C.; Lindström, Björn; Esteves, Francisco; Öhman, Arne

    2014-01-01

    Snakes have provided a serious threat to primates throughout evolution. Furthermore, bites by venomous snakes still cause significant morbidity and mortality in tropical regions of the world. According to the Snake Detection Theory (SDT Isbell, 2006; 2009), the vital need to detect camouflaged snakes provided strong evolutionary pressure to develop astute perceptual capacity in animals that were potential targets for snake attacks. We performed a series of behavioral tests that assessed snake detection under conditions that may have been critical for survival. We used spiders as the control stimulus because they are also a common object of phobias and rated negatively by the general population, thus commonly lumped together with snakes as “evolutionary fear-relevant”. Across four experiments (N = 205) we demonstrate an advantage in snake detection, which was particularly obvious under visual conditions known to impede detection of a wide array of common stimuli, for example brief stimulus exposures, stimuli presentation in the visual periphery, and stimuli camouflaged in a cluttered environment. Our results demonstrate a striking independence of snake detection from ecological factors that impede the detection of other stimuli, which suggests that, consistent with the SDT, they reflect a specific biological adaptation. Nonetheless, the empirical tests we report are limited to only one aspect of this rich theory, which integrates findings across a wide array of scientific disciplines. PMID:25493937

  16. Unusual accelerated rate of deletions and insertions in toxin genes in the venom glands of the pygmy copperhead (Austrelaps labialis) from Kangaroo island.

    Science.gov (United States)

    Doley, Robin; Tram, Nguyen Ngoc Bao; Reza, Md Abu; Kini, R Manjunatha

    2008-02-28

    Toxin profiling helps in cataloguing the toxin present in the venom as well as in searching for novel toxins. The former helps in understanding potential pharmacological profile of the venom and evolution of toxins, while the latter contributes to understanding of novel mechanisms of toxicity and provide new research tools or prototypes of therapeutic agents. The pygmy copperhead (Austrelaps labialis) is one of the less studied species. In this present study, an attempt has been made to describe the toxin profile of A. labialis from Kangaroo Island using the cDNA library of its venom glands. We sequenced 658 clones which represent the common families of toxin genes present in snake venom. They include (a) putative long-chain and short-chain neurotoxins, (b) phospholipase A2, (c) Kunitz-type protease inhibitor, (d) CRISPs, (e) C-type lectins and (f) Metalloproteases. In addition, we have also identified a novel protein with two Kunitz-type domains in tandem similar to bikunin. Interestingly, the cDNA library reveals that most of the toxin families (17 out of 43 toxin genes; approximately 40%) have truncated transcripts due to insertion or deletion of nucleotides. These truncated products might not be functionally active proteins. However, cellular transcripts from the same venom glands are not affected. This unusual higher rate of deletion and insertion of nucleotide in toxin genes may be responsible for the lower toxicity of A. labialis venom of Kangroo Island and have significant effect on evolution of toxin genes.

  17. Evaluation of antidiphtheria toxin nanobodies

    Directory of Open Access Journals (Sweden)

    Ghada H Shaker

    2010-06-01

    Full Text Available Ghada H ShakerDepartment of Microbiology and Immunology, Faculty of Pharmacy, King Saud University, Riyadh, Kingdom of Saudi ArabiaAbstract: Nanobodies are the smallest fragments of naturally occurring single-domain antibodies that have evolved to be fully functional in the absence of a light chain. Conventional antibodies are glycoproteins comprising two heavy and two light chains. Surprisingly, all members of the Camelidae family possess a fraction of antibodies devoid of both light chains and the first constant domain. These types of antibodies are known as heavy-chain antibody (HcAb nanobodies. There are three subclasses of IgG in dromedaries, namely IgG1, IgG2, and IgG3 of which IgG2 and IgG3 are of the HcAb type. These heavy chain antibodies constitute approximately 50% of the IgG in llama serum and as much as 75% of the IgG in camel serum. In the present work, the different IgG subclasses from an immunized camel (Camelus dromedarius with divalent diphtheria-tetanus vaccine were purified using their different affinity for protein A and protein G and their absorbance measured at 280 nm. Purity control and characterization by 12% sodium dodecyl sulfate-polyacrylamide gel electrophoresis of IgG subclasses was done under reducing conditions. Protein bands were visualized after staining with Coomassie Blue, showing two bands at 50 kDa and 30 kDa for IgG1, while IgG2 and IgG3 produced only one band at 46 kDa and 43 kDa, respectively. An enzyme-linked immunosorbent assay test using diphtheria toxin and purified IgG subclasses from the immunized camel were performed to evaluate their efficiency. Compared with conventional IgG1, heavy chain antibodies (nanobodies were shown to be more efficient in binding to diphtheria toxin antigen. This study revealed the possibility of using IgG2 and IgG3 nanobodies as an effective antitoxin for the treatment of diphtheria in humans.Keywords: camel, heavy chain antibody, HcAb, nanobodies, immunoglobulin, Ig

  18. Cloning and characterization of a basic phospholipase A2 homologue from Micrurus corallinus (coral snake) venom gland.

    Science.gov (United States)

    de Oliveira, Ursula Castro; Assui, Alessandra; da Silva, Alvaro Rossan de Brandão Prieto; de Oliveira, Jane Silveira; Ho, Paulo Lee

    2003-09-01

    During the cloning of abundant cDNAs expressed in the Micrurus corallinus coral snake venom gland, several putative toxins, including a phospholipase A2 homologue cDNA (clone V2), were identified. The V2 cDNA clone codes for a potential coral snake toxin with a signal peptide of 27 amino acid residues plus a predicted mature protein with 119 amino acid residues. The deduced protein is highly similar to known phospholipases A2, with seven deduced S-S bridges at the same conserved positions. This protein was expressed in Escherichia coli as a His-tagged protein that allowed the rapid purification of the recombinant protein. This protein was used to generate antibodies, which recognized the recombinant protein in Western blot. This antiserum was used to screen a large number of venoms, showing a ubiquitous distribution of immunorelated proteins in all elapidic venoms but not in the viperidic Bothrops jararaca venom. This is the first description of a complete primary structure of a phospholipase A2 homologue deduced by cDNA cloning from a coral snake.

  19. Sea Snake Harvest in the Gulf of Thailand

    DEFF Research Database (Denmark)

    Van Cao, Nguyen; Thien Tao, Nguyen; Moore, Amelia

    2014-01-01

    Abstract: Conservation of sea snakes is virtually nonexistent in Asia, and its role in human–snake interactions in terms of catch, trade, and snakebites as an occupational hazard is mostly unexplored. We collected data on sea snake landings from the Gulf of Thailand, a hotspot for sea snake harvest...... sell snakes to merchants who sort, package, and ship the snakes to various destinations in Vietnam and China for human consumption and as a source of traditional remedies. Annually, 82 t, roughly equal to 225,500 individuals, of live sea snakes are brought to ports. To our knowledge, this rate...... of harvest constitutes one of the largest venomous snake and marine reptile harvest activities in the world today. Lapemis curtus and Hydrophis cyanocinctus constituted about 85% of the snake biomass, and Acalyptophis peronii, Aipysurus eydouxii, Hydrophis atriceps, H. belcheri, H. lamberti, and H. ornatus...

  20. Safe Handling of Snakes in an ED Setting.

    Science.gov (United States)

    Cockrell, Melanie; Swanson, Kristofer; Sanders, April; Prater, Samuel; von Wenckstern, Toni; Mick, JoAnn

    2017-01-01

    Efforts to improve consistency in management of snakes and venomous snake bites in the emergency department (ED) can improve patient and staff safety and outcomes, as well as improve surveillance data accuracy. The emergency department at a large academic medical center identified an opportunity to implement a standardized process for snake disposal and identification to reduce staff risk exposure to snake venom from snakes patients brought with them to the ED. A local snake consultation vendor and zoo Herpetologist assisted with development of a process for snake identification and disposal. All snakes have been identified and securely disposed of using the newly implemented process and no safety incidents have been reported. Other emergency department settings may consider developing a standardized process for snake disposal using listed specialized consultants combined with local resources and suppliers to promote employee and patient safety. Copyright © 2017 Emergency Nurses Association. Published by Elsevier Inc. All rights reserved.

  1. Snake Venom Metalloproteinases and Their Peptide Inhibitors from Myanmar Russell’s Viper Venom

    Directory of Open Access Journals (Sweden)

    Khin Than Yee

    2016-12-01

    Full Text Available Russell’s viper bites are potentially fatal from severe bleeding, renal failure and capillary leakage. Snake venom metalloproteinases (SVMPs are attributed to these effects. In addition to specific antivenom therapy, endogenous inhibitors from snakes are of interest in studies of new treatment modalities for neutralization of the effect of toxins. Two major snake venom metalloproteinases (SVMPs: RVV-X and Daborhagin were purified from Myanmar Russell’s viper venom using a new purification strategy. Using the Next Generation Sequencing (NGS approach to explore the Myanmar RV venom gland transcriptome, mRNAs of novel tripeptide SVMP inhibitors (SVMPIs were discovered. Two novel endogenous tripeptides, pERW and pEKW were identified and isolated from the crude venom. Both purified SVMPs showed caseinolytic activity. Additionally, RVV-X displayed specific proteolytic activity towards gelatin and Daborhagin showed potent fibrinogenolytic activity. These activities were inhibited by metal chelators. Notably, the synthetic peptide inhibitors, pERW and pEKW, completely inhibit the gelatinolytic and fibrinogenolytic activities of respective SVMPs at 5 mM concentration. These complete inhibitory effects suggest that these tripeptides deserve further study for development of a therapeutic candidate for Russell’s viper envenomation.

  2. Inventing an arsenal: adaptive evolution and neofunctionalization of snake venom phospholipase A2 genes

    Directory of Open Access Journals (Sweden)

    Lynch Vincent J

    2007-01-01

    Full Text Available Abstract Background Gene duplication followed by functional divergence has long been hypothesized to be the main source of molecular novelty. Convincing examples of neofunctionalization, however, remain rare. Snake venom phospholipase A2 genes are members of large multigene families with many diverse functions, thus they are excellent models to study the emergence of novel functions after gene duplications. Results Here, I show that positive Darwinian selection and neofunctionalization is common in snake venom phospholipase A2 genes. The pattern of gene duplication and positive selection indicates that adaptive molecular evolution occurs immediately after duplication events as novel functions emerge and continues as gene families diversify and are refined. Surprisingly, adaptive evolution of group-I phospholipases in elapids is also associated with speciation events, suggesting adaptation of the phospholipase arsenal to novel prey species after niche shifts. Mapping the location of sites under positive selection onto the crystal structure of phospholipase A2 identified regions evolving under diversifying selection are located on the molecular surface and are likely protein-protein interactions sites essential for toxin functions. Conclusion These data show that increases in genomic complexity (through gene duplications can lead to phenotypic complexity (venom composition and that positive Darwinian selection is a common evolutionary force in snake venoms. Finally, regions identified under selection on the surface of phospholipase A2 enzymes are potential candidate sites for structure based antivenin design.

  3. Inventing an arsenal: adaptive evolution and neofunctionalization of snake venom phospholipase A2 genes.

    Science.gov (United States)

    Lynch, Vincent J

    2007-01-18

    Gene duplication followed by functional divergence has long been hypothesized to be the main source of molecular novelty. Convincing examples of neofunctionalization, however, remain rare. Snake venom phospholipase A2 genes are members of large multigene families with many diverse functions, thus they are excellent models to study the emergence of novel functions after gene duplications. Here, I show that positive Darwinian selection and neofunctionalization is common in snake venom phospholipase A2 genes. The pattern of gene duplication and positive selection indicates that adaptive molecular evolution occurs immediately after duplication events as novel functions emerge and continues as gene families diversify and are refined. Surprisingly, adaptive evolution of group-I phospholipases in elapids is also associated with speciation events, suggesting adaptation of the phospholipase arsenal to novel prey species after niche shifts. Mapping the location of sites under positive selection onto the crystal structure of phospholipase A2 identified regions evolving under diversifying selection are located on the molecular surface and are likely protein-protein interactions sites essential for toxin functions. These data show that increases in genomic complexity (through gene duplications) can lead to phenotypic complexity (venom composition) and that positive Darwinian selection is a common evolutionary force in snake venoms. Finally, regions identified under selection on the surface of phospholipase A2 enzymes are potential candidate sites for structure based antivenin design.

  4. Toxins Best Paper Award 2015

    Directory of Open Access Journals (Sweden)

    Vernon L. Tesh

    2015-03-01

    Full Text Available In order to recognize outstanding papers related to biotoxins and toxinology that have been published in Toxins, the Editorial Board established an annual “Toxins Best Paper Award”. We are pleased to announce the first “Toxins Best Paper Award” for 2015. Nominations were selected by the Editorial Board members, with all papers published in 2011 eligible for consideration. Reviews and original research articles were evaluated separately. Following review and voting by the Toxins Best Paper Award Committee, the following three papers have won Toxins Best Paper Awards for 2015:[...

  5. [Protein toxins of Staphylococcus aureus].

    Science.gov (United States)

    Shamsutdinov, A F; Tiurin, Iu A

    2014-01-01

    Main scientific-research studies regarding protein bacterial toxins of the most widespread bacteria that belong to Staphylococcus spp. genus and in particular the most pathogenic species for humans--Staphylococcus aureus, are analyzed. Structural and biological properties of protein toxins that have received the name of staphylococcus pyrogenic toxins (PTSAg) are presented. Data regarding genetic regulation of secretion and synthesis of these toxins and 3 main regulatory genetic systems (agr--accessory gene regulator, xpr--extracellular protein regulator, sar--staphylococcal accessory regulator) that coordinate synthesis of the most important protein toxins and enzymes for virulence of S. aureus, are presented.

  6. 2015 OLC FEMA Lidar: Snake River, ID

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Quantum Spatial has collected Light Detection and Ranging (LiDAR) data for the Oregon LiDAR Consortium (OLC) Snake River FEMA study area. This study area is located...

  7. Spin flipping in rings with Siberian Snakes

    Energy Technology Data Exchange (ETDEWEB)

    Mane, S.R. [Convergent Computing Inc., P.O. Box 561, Shoreham, NY 11786 (United States)], E-mail: srmane@optonline.net

    2009-07-01

    I display numerical spin tracking simulations for spin flippers in model storage rings with full or nearly full Siberian Snakes. In many cases, the results differ from the predictions using the Froissart-Stora formula.

  8. Friction enhancement in concertina locomotion of snakes

    Science.gov (United States)

    Marvi, Hamidreza; Hu, David L.

    2012-01-01

    Narrow crevices are challenging terrain for most organisms and biomimetic robots. Snakes move through crevices using sequential folding and unfolding of their bodies in the manner of an accordion or concertina. In this combined experimental and theoretical investigation, we elucidate this effective means of moving through channels. We measure the frictional properties of corn snakes, their body kinematics and the transverse forces they apply to channels of varying width and inclination. To climb channels inclined at 60°, we find snakes use a combination of ingenious friction-enhancing techniques, including digging their ventral scales to double their frictional coefficient and pushing channel walls transversely with up to nine times body weight. Theoretical modelling of a one-dimensional n-linked crawler is used to calculate the transverse force factor of safety: we find snakes push up to four times more than required to prevent sliding backwards, presumably trading metabolic energy for an assurance of wall stability. PMID:22728386

  9. Structure-function relationships of sea anemone toxin II from Anemonia sulcata.

    Science.gov (United States)

    Barhanin, J; Hugues, M; Schweitz, H; Vincent, J P; Lazdunski, M

    1981-06-10

    Chemical modifications of sea anemone toxin II from Anemonia sulcata have been used to study the residues involved in its toxic action on crabs and mice and in its binding properties to the Na+ channel of rat brain synaptosomes. Guanidination of th epsilon-amino groups of lysines 35, 36, and 46 with O-methylisourea hydrogen sulfate did not change the net charge of the toxin molecule and had no effect upon its toxic and binding properties. Either acetylation or fluorescamine treatment of the toxin that destroyed the positive charges of the three epsilon-amino groups and of the alpha-amino function of Gly produced an almost complete loss of toxicity and a considerable decrease in the binding activity. Iodination of the toxin on His induced practically no loss of toxic or binding properties. Carbethoxylation of both histidines 32 and 37 with diethyl pyrocarbonate provoked an important decrease of both the toxicity and the binding activity. Modifications of the guanidine side chain of Arg with 1,2-cyclohexanedione fully destroyed both toxicity and binding of the toxin to the Na+ channel. Modification of the carboxylate functions of Asp, Asp, and of the COOH-terminal Gln with glycine ethyl ester in the presence of a soluble carbodiimide completely abolished the toxicity but left the affinity for the sea anemone toxin receptor unchanged. The antagonist character of this carboxylate-modified derivative was further confirmed by electrophysiological and Na+ flux experiments. The theoretical and practical significance of these results are discussed.

  10. CD44 Promotes intoxication by the clostridial iota-family toxins.

    Directory of Open Access Journals (Sweden)

    Darran J Wigelsworth

    Full Text Available Various pathogenic clostridia produce binary protein toxins associated with enteric diseases of humans and animals. Separate binding/translocation (B components bind to a protein receptor on the cell surface, assemble with enzymatic (A component(s, and mediate endocytosis of the toxin complex. Ultimately there is translocation of A component(s from acidified endosomes into the cytosol, leading to destruction of the actin cytoskeleton. Our results revealed that CD44, a multifunctional surface protein of mammalian cells, facilitates intoxication by the iota family of clostridial binary toxins. Specific antibody against CD44 inhibited cytotoxicity of the prototypical Clostridium perfringens iota toxin. Versus CD44(+ melanoma cells, those lacking CD44 bound less toxin and were dose-dependently resistant to C. perfringens iota, as well as Clostridium difficile and Clostridium spiroforme iota-like, toxins. Purified CD44 specifically interacted in vitro with iota and iota-like, but not related Clostridium botulinum C2, toxins. Furthermore, CD44 knockout mice were resistant to iota toxin lethality. Collective data reveal an important role for CD44 during intoxication by a family of clostridial binary toxins.

  11. Experimental Infection of Snakes with Ophidiomyces ophiodiicola Causes Pathological Changes That Typify Snake Fungal Disease.

    Science.gov (United States)

    Lorch, Jeffrey M; Lankton, Julia; Werner, Katrien; Falendysz, Elizabeth A; McCurley, Kevin; Blehert, David S

    2015-11-17

    Snake fungal disease (SFD) is an emerging skin infection of wild snakes in eastern North America. The fungus Ophidiomyces ophiodiicola is frequently associated with the skin lesions that are characteristic of SFD, but a causal relationship between the fungus and the disease has not been established. We experimentally infected captive-bred corn snakes (Pantherophis guttatus) in the laboratory with pure cultures of O. ophiodiicola. All snakes in the infected group (n = 8) developed gross and microscopic lesions identical to those observed in wild snakes with SFD; snakes in the control group (n = 7) did not develop skin infections. Furthermore, the same strain of O. ophiodiicola used to inoculate snakes was recovered from lesions of all animals in the infected group, but no fungi were isolated from individuals in the control group. Monitoring progression of lesions throughout the experiment captured a range of presentations of SFD that have been described in wild snakes. The host response to the infection included marked recruitment of granulocytes to sites of fungal invasion, increased frequency of molting, and abnormal behaviors, such as anorexia and resting in conspicuous areas of enclosures. While these responses may help snakes to fight infection, they could also impact host fitness and may contribute to mortality in wild snakes with chronic O. ophiodiicola infection. This work provides a basis for understanding the pathogenicity of O. ophiodiicola and the ecology of SFD by using a model system that incorporates a host species that is easy to procure and maintain in the laboratory. Skin infections in snakes, referred to as snake fungal disease (SFD), have been reported with increasing frequency in wild snakes in the eastern United States. While most of these infections are associated with the fungus Ophidiomyces ophiodiicola, there has been no conclusive evidence to implicate this fungus as a primary pathogen. Furthermore, it is not understood why the

  12. Nest defense- Grassland bird responses to snakes

    Science.gov (United States)

    Ellison, Kevin S.; Ribic, Christine

    2012-01-01

    Predation is the primary source of nest mortality for most passerines; thus, behaviors to reduce the impacts of predation are frequently quantified to study learning, adaptation, and coevolution among predator and prey species. Video surveillance of nests has made it possible to examine real-time parental nest defense. During 1999-2009, we used video camera systems to monitor 518 nests of grassland birds. We reviewed video of 48 visits by snakes to 34 nests; 37 of these visits resulted in predation of active nests. When adult birds encountered snakes at the nest (n = 33 visits), 76% of the encounters resulted in a form of nest defense (nonaggressive or aggressive); in 47% of the encounters, birds physically struck snakes. When defending nests, most birds pecked at the snakes; Eastern Meadowlarks (Sturnella magna) and Bobolinks (Dolichonyx oryzivorus) pecked most frequently in anyone encounter. Also, two Eastern Meadowlarks ran around snakes, frequently with wings spread, and three Bobolinks struck at snakes from the air. Nest defense rarely appeared to alter snake behavior; the contents of seven nests defended aggressively and two nests defended nonaggressively were partially depredated, whereas the contents of six nests defended each way were consumed completely. One fledgling was produced at each of three nests that had been aggressively defended. During aggressive defense, one snake appeared to be driven away and one was wounded. Our findings should be a useful starting point for further research. For example, future researchers may be able to determine whether the behavioral variation we observed in nest defense reflects species differences, anatomic or phylogenetic constraints, or individual differences related to a bird's prior experience. There appears to be much potential for studying nest defense behavior using video recording of both real and simulated encounters. 

  13. Prey handling and diet of Louisiana pine snakes (Pituophis ruthveni) and black pine snakes (P. melanoleucus lodingi), with comparisons to other selected colubrid snakes

    Science.gov (United States)

    D. Craig Rudolph; Shirley J. Burgdorf; Richard N. Conner; Christopher S. Collins; Daniel Saenz; Richard R. Schaefer; Toni Trees; C. Michael Duran; Marc Ealy; John G. Himes

    2002-01-01

    Diet and prey handling behavior were determined for Louisiana pine snakes (Pituophis ruthveni) and black pine snakes (P. melanoleucus lodingi). Louisiana pine snakes prey heavily on Baird's pocket gophers (Geomys breviceps), with which they are sympatric, and exhibit specialized behaviors that facilitate...

  14. Phylogeny, ecology, and heart position in snakes

    DEFF Research Database (Denmark)

    Gartner, Gabriel E.A.; Hicks, James W.; Manzani, Paulo R.

    2010-01-01

    The cardiovascular system of all animals is affected by gravitational pressure gradients, the intensity of which varies according to organismic features, behavior, and habitat occupied. A previous nonphylogenetic analysis of heart position in snakes-which often assume vertical postures-found the ......The cardiovascular system of all animals is affected by gravitational pressure gradients, the intensity of which varies according to organismic features, behavior, and habitat occupied. A previous nonphylogenetic analysis of heart position in snakes-which often assume vertical postures......, whereas an anterior heart position would not be needed in aquatic habitats, where the effects of gravity are less pronounced. We analyzed a new data set of 155 species from five major families of Alethinophidia (one of the two major branches of snakes, the other being blind snakes, Scolecophidia) using...... counterparts. The best‐fit model predicting snake heart position included aspects of both habitat and clade and indicated that arboreal snakes in our study tend to have hearts placed more posteriorly, opposite the trend identified in previous studies. Phylogenetic signal in relative heart position was apparent...

  15. Purification and pharmacological properties of eight sea anemone toxins from Anemonia sulcata, Anthopleura xanthogrammica, Stoichactis giganteus, and Actinodendron plumosum.

    Science.gov (United States)

    Schweitz, H; Vincent, J P; Barhanin, J; Frelin, C; Linden, G; Hugues, M; Lazdunski, M

    1981-09-01

    Eight different polypeptide toxins from sea anemones of four different origins (Anemonia sulcata, Anthopleura xanthogrammica, Stoichactis giganteus, and Actinodendron plumosum) have been studied. Three of these toxins are new; the purification procedure for the five other ones has been improved. Sea anemone toxins were assayed (i) for their toxicity to crabs and mice, (ii) for their affinity for the specific sea anemone toxin receptor situated on the Na+ channels of rat brain synaptosomes, and (iii) for their capacity to increase, in synergy with veratridine, the rate of 22Na+ entry into neuroblastoma cells via the Na+ channel. Some of the toxins are more active on crustaceans, whereas others are more toxic to mammals. A very good correlation exists between the toxic activity to mice, the affinity of the toxin for the Na+ channel in rat brain synaptosomes, and the stimulating effect on 22 Na+ uptake by neuroblastoma cells. The observation has also been made that the most cationic toxins are also the most active on mammals and the least active on crustaceans. Toxicities (LD50) to mice of the most active sea anemone toxins and of the most active scorpion toxins are similar, and sea anemone toxins at high enough concentrations prevent binding of scorpion toxins to their receptor. However, scorpion toxins have affinities for the Na+ channel which are approximately 60 times higher than those found for the most active sea anemone toxins. Three sea anemone toxins appear to be more interesting than toxin II from A. sulcata (the "classical" sea anemone toxin) for studies of the Na+ channel structure and mechanism when the source of the channel is of a mammalian origin. Two of these three toxins can be radiolabeled with iodine while retaining their toxic activity; they appear to be useful tools for future biochemical studies of the Na+ channel.

  16. Chemical basis of prey recognition in thamnophiine snakes: the unexpected new roles of parvalbumins.

    Directory of Open Access Journals (Sweden)

    Maïté Smargiassi

    Full Text Available Detecting and locating prey are key to predatory success within trophic chains. Predators use various signals through specialized visual, olfactory, auditory or tactile sensory systems to pinpoint their prey. Snakes chemically sense their prey through a highly developed auxiliary olfactory sense organ, the vomeronasal organ (VNO. In natricine snakes that are able to feed on land and water, the VNO plays a critical role in predatory behavior by detecting cues, known as vomodors, which are produced by their potential prey. However, the chemical nature of these cues remains unclear. Recently, we demonstrated that specific proteins-parvalbumins-present in the cutaneous mucus of the common frog (Rana temporaria may be natural chemoattractive proteins for these snakes. Here, we show that parvalbumins and parvalbumin-like proteins, which are mainly intracellular, are physiologically present in the epidermal mucous cells and mucus of several frog and fish genera from both fresh and salt water. These proteins are located in many tissues and function as Ca(2+ buffers. In addition, we clarified the intrinsic role of parvalbumins present in the cutaneous mucus of amphibians and fishes. We demonstrate that these Ca(2+-binding proteins participate in innate bacterial defense mechanisms by means of calcium chelation. We show that these parvalbumins are chemoattractive for three different thamnophiine snakes, suggesting that these chemicals play a key role in their prey-recognition mechanism. Therefore, we suggest that recognition of parvalbumin-like proteins or other calcium-binding proteins by the VNO could be a generalized prey-recognition process in snakes. Detecting innate prey defense mechanism compounds may have driven the evolution of this predator-prey interaction.

  17. Chemical basis of prey recognition in thamnophiine snakes: the unexpected new roles of parvalbumins.

    Science.gov (United States)

    Smargiassi, Maïté; Daghfous, Gheylen; Leroy, Baptiste; Legreneur, Pierre; Toubeau, Gerard; Bels, Vincent; Wattiez, Ruddy

    2012-01-01

    Detecting and locating prey are key to predatory success within trophic chains. Predators use various signals through specialized visual, olfactory, auditory or tactile sensory systems to pinpoint their prey. Snakes chemically sense their prey through a highly developed auxiliary olfactory sense organ, the vomeronasal organ (VNO). In natricine snakes that are able to feed on land and water, the VNO plays a critical role in predatory behavior by detecting cues, known as vomodors, which are produced by their potential prey. However, the chemical nature of these cues remains unclear. Recently, we demonstrated that specific proteins-parvalbumins-present in the cutaneous mucus of the common frog (Rana temporaria) may be natural chemoattractive proteins for these snakes. Here, we show that parvalbumins and parvalbumin-like proteins, which are mainly intracellular, are physiologically present in the epidermal mucous cells and mucus of several frog and fish genera from both fresh and salt water. These proteins are located in many tissues and function as Ca(2+) buffers. In addition, we clarified the intrinsic role of parvalbumins present in the cutaneous mucus of amphibians and fishes. We demonstrate that these Ca(2+)-binding proteins participate in innate bacterial defense mechanisms by means of calcium chelation. We show that these parvalbumins are chemoattractive for three different thamnophiine snakes, suggesting that these chemicals play a key role in their prey-recognition mechanism. Therefore, we suggest that recognition of parvalbumin-like proteins or other calcium-binding proteins by the VNO could be a generalized prey-recognition process in snakes. Detecting innate prey defense mechanism compounds may have driven the evolution of this predator-prey interaction.

  18. Negative snakes in JET: evidence for negative shear

    Energy Technology Data Exchange (ETDEWEB)

    Gill, R.D.; Alper, B.; Edwards, A.W. [Commission of the European Communities, Abingdon (United Kingdom). JET Joint Undertaking; Pearson, D. [Reading Univ. (United Kingdom)

    1994-07-01

    The signature of the negative snakes from the soft X-ray cameras is very similar to the more usual snakes except that the localised region of the snake has, compared with its surroundings, decreased rather than increased emission. Circumstances where negative snakes have been seen are reviewed. The negative snake appears as a region of increased resistance and of increased impurity density. The relationship between the shear and the current perturbation is shown, and it seem probable that the magnetic shear is reversed at the point of the negative snake, i.e. that q is decreasing with radius. 6 refs., 6 figs.

  19. Venomic Analysis of the Poorly Studied Desert Coral Snake, Micrurus tschudii tschudii, Supports the 3FTx/PLA₂ Dichotomy across Micrurus Venoms.

    Science.gov (United States)

    Sanz, Libia; Pla, Davinia; Pérez, Alicia; Rodríguez, Yania; Zavaleta, Alfonso; Salas, Maria; Lomonte, Bruno; Calvete, Juan J

    2016-06-07

    The venom proteome of the poorly studied desert coral snake Micrurus tschudii tschudii was unveiled using a venomic approach, which identified ≥38 proteins belonging to only four snake venom protein families. The three-finger toxins (3FTxs) constitute, both in number of isoforms (~30) and total abundance (93.6% of the venom proteome), the major protein family of the desert coral snake venom. Phospholipases A₂ (PLA₂s; seven isoforms, 4.1% of the venom proteome), 1-3 Kunitz-type proteins (1.6%), and 1-2 l-amino acid oxidases (LAO, 0.7%) complete the toxin arsenal of M. t. tschudii. Our results add to the growing evidence that the occurrence of two divergent venom phenotypes, i.e., 3FTx- and PLA₂-predominant venom proteomes, may constitute a general trend across the cladogenesis of Micrurus. The occurrence of a similar pattern of venom phenotypic variability among true sea snake (Hydrophiinae) venoms suggests that the 3FTx/PLA₂ dichotomy may be widely distributed among Elapidae venoms.

  20. Venomic Analysis of the Poorly Studied Desert Coral Snake, Micrurus tschudii tschudii, Supports the 3FTx/PLA2 Dichotomy across Micrurus Venoms

    Science.gov (United States)

    Sanz, Libia; Pla, Davinia; Pérez, Alicia; Rodríguez, Yania; Zavaleta, Alfonso; Salas, Maria; Lomonte, Bruno; Calvete, Juan J.

    2016-01-01

    The venom proteome of the poorly studied desert coral snake Micrurus tschudii tschudii was unveiled using a venomic approach, which identified ≥38 proteins belonging to only four snake venom protein families. The three-finger toxins (3FTxs) constitute, both in number of isoforms (~30) and total abundance (93.6% of the venom proteome), the major protein family of the desert coral snake venom. Phospholipases A2 (PLA2s; seven isoforms, 4.1% of the venom proteome), 1–3 Kunitz-type proteins (1.6%), and 1–2 l-amino acid oxidases (LAO, 0.7%) complete the toxin arsenal of M. t. tschudii. Our results add to the growing evidence that the occurrence of two divergent venom phenotypes, i.e., 3FTx- and PLA2-predominant venom proteomes, may constitute a general trend across the cladogenesis of Micrurus. The occurrence of a similar pattern of venom phenotypic variability among true sea snake (Hydrophiinae) venoms suggests that the 3FTx/PLA2 dichotomy may be widely distributed among Elapidae venoms. PMID:27338473

  1. Venomic Analysis of the Poorly Studied Desert Coral Snake, Micrurus tschudii tschudii, Supports the 3FTx/PLA2 Dichotomy across Micrurus Venoms

    Directory of Open Access Journals (Sweden)

    Libia Sanz

    2016-06-01

    Full Text Available The venom proteome of the poorly studied desert coral snake Micrurus tschudii tschudii was unveiled using a venomic approach, which identified ≥38 proteins belonging to only four snake venom protein families. The three-finger toxins (3FTxs constitute, both in number of isoforms (~30 and total abundance (93.6% of the venom proteome, the major protein family of the desert coral snake venom. Phospholipases A2 (PLA2s; seven isoforms, 4.1% of the venom proteome, 1–3 Kunitz-type proteins (1.6%, and 1–2 l-amino acid oxidases (LAO, 0.7% complete the toxin arsenal of M. t. tschudii. Our results add to the growing evidence that the occurrence of two divergent venom phenotypes, i.e., 3FTx- and PLA2-predominant venom proteomes, may constitute a general trend across the cladogenesis of Micrurus. The occurrence of a similar pattern of venom phenotypic variability among true sea snake (Hydrophiinae venoms suggests that the 3FTx/PLA2 dichotomy may be widely distributed among Elapidae venoms.

  2. Procoagulant snake venoms have differential effects in animal plasmas: Implications for antivenom testing in animal models.

    Science.gov (United States)

    Maduwage, Kalana P; Scorgie, Fiona E; Lincz, Lisa F; O'Leary, Margaret A; Isbister, Geoffrey K

    2016-01-01

    Animal models are used to test toxic effects of snake venoms/toxins and the antivenom required to neutralise them. However, venoms that cause clinically relevant coagulopathy in humans may have differential effects in animals. We aimed to investigate the effect of different procoagulant snake venoms on various animal plasmas. Prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen and D-dimer levels were measured in seven animal plasmas (human, rabbit, cat, guinea pig, pig, cow and rat). In vitro clotting times were then used to calculate the effective concentration (EC50) in each plasma for four snake venoms with different procoagulant toxins: Pseudonaja textilis, Daboia russelli, Echis carinatus and Calloselasma rhodostoma. Compared to human, PT and aPTT were similar for rat, rabbit and pig, but double for cat and cow, while guinea pig had similar aPTT but double PT. Fibrinogen and D-dimer levels were similar for all species. Human and rabbit plasmas had the lowest EC50 for P. textilis (0.1 and 0.4 μg/ml), D. russelli (0.4 and 0.1 μg/ml), E. carinatus (0.6 and 0.1 μg/ml) venoms respectively, while cat plasma had the lowest EC50 for C. rhodostoma (11 μg/ml) venom. Cow, rat, pig and guinea pig plasmas were highly resistant to all four venoms with EC50 10-fold that of human. Different animal plasmas have varying susceptibility to procoagulant venoms, and excepting rabbits, animal models are not appropriate to test procoagulant activity. In vitro assays on human plasma should instead be adopted for this purpose. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Venom and Purified Toxins of the Spectacled Cobra (Naja naja) from Pakistan: Insights into Toxicity and Antivenom Neutralization

    OpenAIRE

    Wong, Kin Ying; Tan, Choo Hock; Tan, Nget Hong

    2016-01-01

    Geographical variations of snake venoms can result in suboptimal effectiveness of Indian antivenoms that are currently used in most South Asian countries. This study investigated the toxicity and neutralization profile of the venom and toxins from Pakistani spectacled cobra, Naja naja, using VINS polyvalent antivenom (VPAV, India), Naja kaouthia monovalent antivenom (NKMAV, Thailand), and neuro bivalent antivenom (NBAV, Taiwan). Cation-exchange and reverse-phase high-performance liquid chroma...

  4. Synergistic activity between Bacillus thuringiensis Cry1Ab and Cry1Ac toxins against maize stem borer (Chilo partellus Swinhoe).

    Science.gov (United States)

    Sharma, P; Nain, V; Lakhanpaul, S; Kumar, P A

    2010-07-01

    To select a toxin combination for the management of maize stem borer (Chilo partellus) and to understand possible mechanism of synergism among Bacillus thuringiensis Cry1A toxins tested. Three Cry1A toxins were over expressed in Escherichia coli strain JM105 and used for diet overlay insect bioassay against C. partellus neonate larvae, both alone and in combinations. Probit analysis revealed that the three Cry1A toxins tested have synergistic effect against C. partellus larvae. In vitro binding analysis of fluorescein isothiocyanate (FITC)-labelled Cry1A toxins to midgut brush border membrane vesicle (BBMV) shows that increase in toxicity is directly correlated to an increase in binding of toxin mix. A high Cry1Ac to Cry1Ab ratio leads to an increase in efficacy of these toxins towards C. partellus larvae and this increase in toxicity comes from an increase in toxin binding. Use of Cry1Ab and Cry1Ac combination could be an effective approach to control C. partellus. Furthermore, we show it first time that possible reason behind increase in toxicity of synergistic Cry1A proteins is an increase in toxin binding.

  5. Effect of amino acids near the RGD sequence on binding activities between αIIbβ3 integrin and fibrinogen in the presence of RGD-containing synthetic peptides from elegantin and angustatin.

    Science.gov (United States)

    Oyama, Etsuko; Takahashi, Hidenobu; Ishii, Kazuyuki

    2017-10-01

    Elegantin and angustatin, which were isolated from the snake venoms of Protobothrops elegans and Dendroaspis angusticeps, markedly inhibit binding between platelet integrins and fibrinogen via the Arg-Gly-Asp (RGD) sequence. Angustatin, which is a three-finger toxin containing the RGD sequence, inhibits platelet aggregation almost ten times more strongly than disintegrin isolated from the venoms of Viperidae and Crotalidae. The RGD sequences of both polypeptides are located at the top of hairpin loops, and the composition of the RGD loop is very important for binding to integrin. We investigated the effects of synthetic RGD loop peptides from angustatin and elegantin on ADP- or collagen-induced platelet aggregation and αIIbβ3-fibrinogen binding. Synthetic angustatin (PRGDMP)-type peptides inhibited platelet aggregation more strongly than elegantin (ARGDDX)-type peptides. In particular, the cyclic angustatin peptide (CPRGDMPC) inhibited ADP- and collagen-induced platelet aggregation at least 10-50 times more strongly than the other peptides. The cyclic angustatin peptide (CPRGDMPC) was also the strongest inhibitor of binding between αIIbβ3 and fibrinogen, the IC50 of this peptide was approximately 2.58μM. Regarding the inhibition of binding between αIIbβ3 and fibrinogen, CPRGDMPC demonstrated a stronger inhibitory and more stable effect in the presence of Mg2+ than in the presence of Ca2+. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Dominant negative mutants of Bacillus thuringiensis Cry1Ab toxin function as anti-toxins: demonstration of the role of oligomerization in toxicity.

    Directory of Open Access Journals (Sweden)

    Claudia Rodríguez-Almazán

    Full Text Available Bacillus thuringiensis Cry toxins, that are used worldwide in insect control, kill insects by a mechanism that depends on their ability to form oligomeric pores that insert into the insect-midgut cells. These toxins are being used worldwide in transgenic plants or spray to control insect pests in agriculture. However, a major concern has been the possible effects of these insecticidal proteins on non-target organisms mainly in ecosystems adjacent to agricultural fields.We isolated and characterized 11 non-toxic mutants of Cry1Ab toxin affected in different steps of the mechanism of action namely binding to receptors, oligomerization and pore-formation. These mutant toxins were analyzed for their capacity to block wild type toxin activity, presenting a dominant negative phenotype. The dominant negative phenotype was analyzed at two levels, in vivo by toxicity bioassays against susceptible Manduca sexta larvae and in vitro by pore formation activity in black lipid bilayers. We demonstrate that some mutations located in helix alpha-4 completely block the wild type toxin activity at sub-stoichiometric level confirming a dominant negative phenotype, thereby functioning as potent antitoxins.This is the first reported case of a Cry toxin dominant inhibitor. These data demonstrate that oligomerization is a fundamental step in Cry toxin action and represent a potential mechanism to protect special ecosystems from the possible effect of Cry toxins on non-target organisms.

  7. Anti-snake venom: use and adverse reaction in a snake bite study clinic in Bangladesh

    Directory of Open Access Journals (Sweden)

    MR Amin

    2008-01-01

    Full Text Available Snakebites can present local or systemic envenomation, while neurotoxicity and respiratory paralysis are the main cause of death. The mainstay of management is anti-snake venom (ASV, which is highly effective, but liable to cause severe adverse reactions including anaphylaxis. The types of adverse reaction to polyvalent anti-snake venom have not been previously studied in Bangladesh. In this prospective observational study carried out between 1999 and 2001, in the Snake Bite Study Clinic of Chittagong Medical College Hospital, 35 neurotoxic-snake-bite patients who had received polyvalent anti-snake venom were included while the ones sensitized to different antitoxins and suffering from atopy were excluded. The common neurotoxic features were ptosis (100%, external ophthalmoplegia (94.2%, dysphagia (77.1%, dysphonia (68.5% and broken neck sign (80%. The percentage of anti-snake venom reaction cases was 88.57%; pyrogenic reaction was 80.64%; and anaphylaxis was 64.51%. The common features of anaphylaxis were urticaria (80%; vomiting and wheezing (40%; and angioedema (10%. The anti-snake venom reaction was treated mainly with adrenaline for anaphylaxis and paracetamol suppository in pyrogenic reactions. The average recovery time was 4.5 hours. Due to the danger of reactions the anti-snake venom should not be withheld from a snakebite victim when indicated and appropriate guidelines should be followed for its administration.

  8. Clostridium difficile toxins A and B: Receptors, pores, and translocation into cells.

    Science.gov (United States)

    Orrell, Kathleen E; Zhang, Zhifen; Sugiman-Marangos, Seiji N; Melnyk, Roman A

    2017-08-01

    The most potent toxins secreted by pathogenic bacteria contain enzymatic moieties that must reach the cytosol of target cells to exert their full toxicity. Toxins such as anthrax, diphtheria, and botulinum toxin all use three well-defined functional domains to intoxicate cells: a receptor-binding moiety that triggers endocytosis into acidified vesicles by binding to a specific host-cell receptor, a translocation domain that forms pores across the endosomal membrane in response to acidic pH, and an enzyme that translocates through these pores to catalytically inactivate an essential host cytosolic substrate. The homologous toxins A (TcdA) and Toxin B (TcdB) secreted by Clostridium difficile are large enzyme-containing toxins that for many years have eluded characterization. The cell-surface receptors for these toxins, the non-classical nature of the pores that they form in membranes, and mechanism of translocation have remained undefined, exacerbated, in part, by the lack of any structural information for the central ∼1000 amino acid translocation domain. Recent advances in the identification of receptors for TcdB, high-resolution structural information for the translocation domain, and a model for the pore have begun to shed light on the mode-of-action of these toxins. Here, we will review TcdA/TcdB uptake and entry into mammalian cells, with focus on receptor binding, endocytosis, pore formation, and translocation. We will highlight how these toxins diverge from classical models of translocating toxins, and offer our perspective on key unanswered questions for TcdA/TcdB binding and entry into mammalian cells.

  9. Association of Bordetella dermonecrotic toxin with the extracellular matrix.

    Science.gov (United States)

    Fukui-Miyazaki, Aya; Kamitani, Shigeki; Miyake, Masami; Horiguchi, Yasuhiko

    2010-09-25

    Bordetella dermonecrotic toxin (DNT) causes the turbinate atrophy in swine atrophic rhinitis, caused by a Bordetella bronchiseptica infection of pigs, by inhibiting osteoblastic differentiation. The toxin is not actively secreted from the bacteria, and is presumed to be present in only small amounts in infected areas. How such small amounts can affect target tissues is unknown. Fluorescence microscopy revealed that DNT associated with a fibrillar structure developed on cultured cells. A cellular component cross-linked with DNT conjugated with a cross-linker was identified as fibronectin by mass spectrometry. Colocalization of the fibronectin network on the cells with DNT was also observed by fluorescence microscope. Several lines of evidence suggested that DNT interacts with fibronectin not directly, but through another cellular component that remains to be identified. The colocalization was observed in not only DNT-sensitive cells but also insensitive cells, indicating that the fibronectin network neither serves as a receptor for the toxin nor is involved in the intoxicating procedures. The fibronectin network-associated toxin was easily liberated when the concentration of toxin in the local environment decreased, and was still active. Components in the extracellular matrix are known to regulate activities of various growth factors by binding and liberating them in response to alterations in the extracellular environment. Similarly, the fibronectin-based extracellular matrix may function as a temporary storage system for DNT, enabling small amounts of the toxin to efficiently affect target tissues or cells.

  10. Association of Bordetella dermonecrotic toxin with the extracellular matrix

    Directory of Open Access Journals (Sweden)

    Miyake Masami

    2010-09-01

    Full Text Available Abstract Background Bordetella dermonecrotic toxin (DNT causes the turbinate atrophy in swine atrophic rhinitis, caused by a Bordetella bronchiseptica infection of pigs, by inhibiting osteoblastic differentiation. The toxin is not actively secreted from the bacteria, and is presumed to be present in only small amounts in infected areas. How such small amounts can affect target tissues is unknown. Results Fluorescence microscopy revealed that DNT associated with a fibrillar structure developed on cultured cells. A cellular component cross-linked with DNT conjugated with a cross-linker was identified as fibronectin by mass spectrometry. Colocalization of the fibronectin network on the cells with DNT was also observed by fluorescence microscope. Several lines of evidence suggested that DNT interacts with fibronectin not directly, but through another cellular component that remains to be identified. The colocalization was observed in not only DNT-sensitive cells but also insensitive cells, indicating that the fibronectin network neither serves as a receptor for the toxin nor is involved in the intoxicating procedures. The fibronectin network-associated toxin was easily liberated when the concentration of toxin in the local environment decreased, and was still active. Conclusions Components in the extracellular matrix are known to regulate activities of various growth factors by binding and liberating them in response to alterations in the extracellular environment. Similarly, the fibronectin-based extracellular matrix may function as a temporary storage system for DNT, enabling small amounts of the toxin to efficiently affect target tissues or cells.

  11. Clostridial pore-forming toxins: powerful virulence factors.

    Science.gov (United States)

    Popoff, Michel R

    2014-12-01

    Pore formation is a common mechanism of action for many bacterial toxins. More than one third of clostridial toxins are pore-forming toxins (PFTs) belonging to the β-PFT class. They are secreted as soluble monomers rich in β-strands, which recognize a specific receptor on target cells and assemble in oligomers. Then, they undergo a conformational change leading to the formation of a β-barrel, which inserts into the lipid bilayer forming functional pore. According to their structure, clostridial β-PFTs are divided into several families. Clostridial cholesterol-dependent cytolysins form large pores, which disrupt the plasma membrane integrity. They are potent virulence factors mainly involved in myonecrosis. Clostridial heptameric β-PFTs (aerolysin family and staphylococcal α-hemolysin family) induce small pores which trigger signaling cascades leading to different cell responses according to the cell types and toxins. They are mainly responsible for intestinal diseases, like necrotic enteritis, or systemic diseases/toxic shock from intestinal origin. Clostridial intracellularly active toxins exploit pore formation through the endosomal membrane to translocate the enzymatic component or domain into the cytosol. Single chain protein toxins, like botulinum and tetanus neurotoxins, use hydrophobic α-helices to form pores, whereas clostridial binary toxins encompass binding components, which are structurally and functionally related to β-PFTs, but which have acquired the specific activity to internalize their corresponding enzymatic components. Structural analysis suggests that β-PFTs and binding components share a common evolutionary origin. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Toxins of Amanita phalloides.

    Science.gov (United States)

    Vetter, J

    1998-01-01

    The most poisonous mushroom toxins are produced by Amanita phalloides (death cap). The occurrence and chemistry of three groups of toxins (amatoxins, phallotoxins and virotoxins) are summarized. The concentration and distribution of toxins in certain species are variable, with the young fruit body containing lower, and the well-developed fungus higher concentrations, but there is a high variability among specimens collected in the same region. Regarding phallotoxins, the volva (the ring) is the most poisonous. The most important biochemical effect of amatoxins is the inhibition of RNA polymerases (especially polymerase II). This interaction leads to a tight complex and the inhibition is of a non-competitive type. Non-mammalian polymerases show little sensitivity to amanitins. The amatoxins cause necrosis of the liver, also partly in the kidney, with the cellular changes causing the fragmentation and segregation of all nuclear components. Various groups of somatic cells of emanation resistance have been isolated, including from a mutant of Drosophila melanogaster. The phallotoxins stimulate the polymerization of G-actin and stabilize the F-actin filaments. The interaction of phallotoxins occurs via the small, 15-membered ring, on the left side of the spatial formula. The symptoms of human poisoning and the changes in toxin concentrations in different organs are summarized. Conventional therapy includes: (1) stabilization of patient's condition with the correction of hypoglycaemia and electrolytes; (2) decontamination; and (3) chemotherapy with different compounds. Finally, certain antagonists and protective compounds are reviewed, bearing in mind that today these have more of a theoretical than a practical role.

  13. Experimental infection of snakes with Ophidiomyces ophiodiicola causes pathological changes that typify snake fungal disease

    Science.gov (United States)

    Lorch, Jeffrey M.; Lankton, Julia S.; Werner, Katrien; Falendysz, Elizabeth A.; McCurley, Kevin; Blehert, David S.

    2015-01-01

    Snake fungal disease (SFD) is an emerging skin infection of wild snakes in eastern North America. The fungus Ophidiomyces ophiodiicola is frequently associated with the skin lesions that are characteristic of SFD, but a causal relationship between the fungus and the disease has not been established. We experimentally infected captive-bred corn snakes (Pantherophis guttatus) in the laboratory with pure cultures of O. ophiodiicola. All snakes in the infected group (n = 8) developed gross and microscopic lesions identical to those observed in wild snakes with SFD; snakes in the control group (n = 7) did not develop skin infections. Furthermore, the same strain of O. ophiodiicola used to inoculate snakes was recovered from lesions of all animals in the infected group, but no fungi were isolated from individuals in the control group. Monitoring progression of lesions throughout the experiment captured a range of presentations of SFD that have been described in wild snakes. The host response to the infection included marked recruitment of granulocytes to sites of fungal invasion, increased frequency of molting, and abnormal behaviors, such as anorexia and resting in conspicuous areas of enclosures. While these responses may help snakes to fight infection, they could also impact host fitness and may contribute to mortality in wild snakes with chronic O. ophiodiicola infection. This work provides a basis for understanding the pathogenicity of O. ophiodiicola and the ecology of SFD by using a model system that incorporates a host species that is easy to procure and maintain in the laboratory.

  14. Structural biology of the sequestration and transport of heavy metal toxins: NMR structure determination of roteins containing the -Cys-X-Y-Cys-metal binding motifs. 1998 annual progress report

    Energy Technology Data Exchange (ETDEWEB)

    Opella, S.J.

    1998-06-01

    'The overall goal of the research is to apply the methods of structural biology, which have been previously used primarily in biomedical applications, to bioremediation. The authors are doing this by using NMR spectroscopy to determine the structures of proteins involved in the bacterial mercury detoxification system. The research is based on the premise that the proteins encoded in the genes of the bacterial detoxification system are an untapped source of reagents and, more fundamentally, chemical strategies that can be used to remove heavy metal toxins from the environment. The initial goals are to determine the structures of the proteins of the bacterial mercury detoxification systems responsible for the sequestration and transport of the Hg(II) ions in to the cell where reduction to Hg(O) occurs. These proteins are meP, which is water soluble and can be investigated with multidimensional solution NMR methods, and merT, the transport protein in the membrane that requires solid-state NMR methods. As of June 1998, this report summarizes work after about one and half years of the three-year award. The authors have made significant accomplishments in three aspects of the NMR studies of the proteins of the bacterial mercury detoxification system.'

  15. Cardiovascular Responses of Snakes to Gravitational Gradients

    Science.gov (United States)

    Hsieh, Shi-Tong T.; Lillywhite, H. B.; Ballard, R. E.; Hargens, A. R.; Holton, Emily M. (Technical Monitor)

    1998-01-01

    Snakes are useful vertebrates for studies of gravitational adaptation, owing to their elongate body and behavioral diversification. Scansorial species have evolved specializations for regulating hemodynamics during exposure to gravitational stress, whereas, such adaptations are less well developed in aquatic and non-climbing species. We examined responses of the amphibious snake,\\italicize (Nerodia rhombifera), to increments of Gz (head-to-tail) acceleration force on both a short- and long-arm centrifuge (1.5 vs. 3.7 m radius, from the hub to tail end of snake). We recorded heart rate, dorsal aortic pressure, and carotid arterial blood flow during stepwise 0.25 G increments of Gz force (referenced at the tail) in conscious animals. The Benz tolerance of a snake was determined as the Gz level at which carotid blood flow ceased and was found to be significantly greater at the short- than long-arm centrifuge radius (1.57 Gz vs. 2.0 Gz, respectively; P=0.016). A similar pattern of response was demonstrated in semi-arboreal rat snakes,\\italicize{Elaphe obsoleta}, which are generally more tolerant of Gz force (2.6 Gz at 1.5m radius) than are water snakes. The tolerance differences of the two species reflected cardiovascular responses, which differed quantitatively but not qualitatively: heart rates increased while arterial pressure and blood flow decreased in response to increasing levels of Gz. Thus, in both species of snakes, a reduced gradient of Gz force (associated with greater centrifuge radius) significantly decreases the Gz level that can be tolerated.

  16. A mechanistic interpretation of the action of toxin II from Anemonia sulcata on the cardiac sodium channel.

    Science.gov (United States)

    Schreibmayer, W; Kazerani, H; Tritthart, H A

    1987-07-23

    Cardiac sodium channels, modified by Anemonia sulcata toxin II, have been analyzed by the patch-clamp method. The open state of the modified sodium channels proved to be prolonged highly significantly and reopening from a closed state denoted c*-state frequently occurred, interrupted by silent periods, denoted i*-state. Activation from the c*-state was apparently not affected by toxin action, whereas activation from the i*-state was markedly prolonged. Upon higher depolarizations toxin-induced sodium channels disappeared and this behaviour has been attributed to dissociation of the toxin from the channel by use of a special pulse-protocol. The onset of the toxin effect on the action potential proved to depend on stimulation, and it is concluded that the toxin binds preferentially to the open (o)-state. Taking together the results, a kinetic scheme is suggested for action of the toxin on the cardiac sodium channel.

  17. Gene-trap mutagenesis identifies mammalian genes contributing to intoxication by Clostridium perfringens ε-toxin.

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    Susan E Ivie

    Full Text Available The Clostridium perfringens ε-toxin is an extremely potent toxin associated with lethal toxemias in domesticated ruminants and may be toxic to humans. Intoxication results in fluid accumulation in various tissues, most notably in the brain and kidneys. Previous studies suggest that the toxin is a pore-forming toxin, leading to dysregulated ion homeostasis and ultimately cell death. However, mammalian host factors that likely contribute to ε-toxin-induced cytotoxicity are poorly understood. A library of insertional mutant Madin Darby canine kidney (MDCK cells, which are highly susceptible to the lethal affects of ε-toxin, was used to select clones of cells resistant to ε-toxin-induced cytotoxicity. The genes mutated in 9 surviving resistant cell clones were identified. We focused additional experiments on one of the identified genes as a means of validating the experimental approach. Gene expression microarray analysis revealed that one of the identified genes, hepatitis A virus cellular receptor 1 (HAVCR1, KIM-1, TIM1, is more abundantly expressed in human kidney cell lines than it is expressed in human cells known to be resistant to ε-toxin. One human kidney cell line, ACHN, was found to be sensitive to the toxin and expresses a larger isoform of the HAVCR1 protein than the HAVCR1 protein expressed by other, toxin-resistant human kidney cell lines. RNA interference studies in MDCK and in ACHN cells confirmed that HAVCR1 contributes to ε-toxin-induced cytotoxicity. Additionally, ε-toxin was shown to bind to HAVCR1 in vitro. The results of this study indicate that HAVCR1 and the other genes identified through the use of gene-trap mutagenesis and RNA interference strategies represent important targets for investigation of the process by which ε-toxin induces cell death and new targets for potential therapeutic intervention.

  18. Removal of Paralytic Shellfish Toxins by Probiotic Lactic Acid Bacteria

    Directory of Open Access Journals (Sweden)

    Mari Vasama

    2014-07-01

    Full Text Available Paralytic shellfish toxins (PSTs are non-protein neurotoxins produced by saltwater dinoflagellates and freshwater cyanobacteria. The ability of Lactobacillus rhamnosus strains GG and LC-705 (in viable and non-viable forms to remove PSTs (saxitoxin (STX, neosaxitoxin (neoSTX, gonyautoxins 2 and 3 (GTX2/3, C-toxins 1 and 2 (C1/2 from neutral and acidic solution (pH 7.3 and 2 was examined using HPLC. Binding decreased in the order of STX ~ neoSTX > C2 > GTX3 > GTX2 > C1. Removal of STX and neoSTX (77%–97.2% was significantly greater than removal of GTX3 and C2 (33.3%–49.7%. There were no significant differences in toxin removal capacity between viable and non-viable forms of lactobacilli, which suggested that binding rather than metabolism is the mechanism of the removal of toxins. In general, binding was not affected by the presence of other organic molecules in solution. Importantly, this is the first study to demonstrate the ability of specific probiotic lactic bacteria to remove PSTs, particularly the most toxic PST-STX, from solution. Further, these results warrant thorough screening and assessment of safe and beneficial microbes for their usefulness in the seafood and water industries and their effectiveness in vivo.

  19. Snake instability of dark solitons in fermionic superfluids

    OpenAIRE

    Cetoli, A.; Brand, J.; Scott, R. G.; Dalfovo, F.; Pitaevskii, L. P.

    2013-01-01

    We present numerical calculations of the snake instability in a Fermi superfluid within the Bogoliubov-de Gennes theory of the BEC to BCS crossover using the random phase approximation complemented by time-dependent simulations. We examine the snaking behaviour across the crossover and quantify the timescale and lengthscale of the instability. While the dynamic shows extensive snaking before eventually producing vortices and sound on the BEC side of the crossover, the snaking dynamics is pree...

  20. Ugrizi strupenih kač: Bites by venomous snakes:

    OpenAIRE

    Grenc, Damjan

    2009-01-01

    Eight different species of non-venomous snakes of the Colubridae family, and three different species of poisonous snakes of the Viperidae family are native in Slovenia. In the period between 1999 and October of 2008, 39 snake bites were reported to the Poison Control Centre. The most common clinical findings in snake bite victims are discernible fang marks, rapidly progressive swelling, pain, ecchymosis, lymphangitis, and regional lymphadenitis. Systemic signs of envenomation can be delayed a...

  1. Neurological manifestations of snake bite in Sri Lanka.

    OpenAIRE

    Seneviratne U; Dissanayake S

    2002-01-01

    BACKGROUND AND AIMS: Snake bite is an important cause of mortality and morbidity in certain parts of Sri Lanka. This study was designed to determine the offending snakes, neurological manifestations, disease course, and outcome in neurotoxic envenomation. METHODS AND MATERIAL: Fifty six consecutive patients admitted with neurological manifestations following snake bite were studied prospectively. Data were obtained regarding the offending snakes, neurological symptoms, time taken for onset of...

  2. Toxin Plasmids of Clostridium perfringens

    Science.gov (United States)

    Li, Jihong; Adams, Vicki; Bannam, Trudi L.; Miyamoto, Kazuaki; Garcia, Jorge P.; Uzal, Francisco A.; Rood, Julian I.

    2013-01-01

    SUMMARY In both humans and animals, Clostridium perfringens is an important cause of histotoxic infections and diseases originating in the intestines, such as enteritis and enterotoxemia. The virulence of this Gram-positive, anaerobic bacterium is heavily dependent upon its prolific toxin-producing ability. Many of the ∼16 toxins produced by C. perfringens are encoded by large plasmids that range in size from ∼45 kb to ∼140 kb. These plasmid-encoded toxins are often closely associated with mobile elements. A C. perfringens strain can carry up to three different toxin plasmids, with a single plasmid carrying up to three distinct toxin genes. Molecular Koch's postulate analyses have established the importance of several plasmid-encoded toxins when C. perfringens disease strains cause enteritis or enterotoxemias. Many toxin plasmids are closely related, suggesting a common evolutionary origin. In particular, most toxin plasmids and some antibiotic resistance plasmids of C. perfringens share an ∼35-kb region containing a Tn916-related conjugation locus named tcp (transfer of clostridial plasmids). This tcp locus can mediate highly efficient conjugative transfer of these toxin or resistance plasmids. For example, conjugative transfer of a toxin plasmid from an infecting strain to C. perfringens normal intestinal flora strains may help to amplify and prolong an infection. Therefore, the presence of toxin genes on conjugative plasmids, particularly in association with insertion sequences that may mobilize these toxin genes, likely provides C. perfringens with considerable virulence plasticity and adaptability when it causes diseases originating in the gastrointestinal tract. PMID:23699255

  3. Sequestered defensive toxins in tetrapod vertebrates: principles, patterns, and prospects for future studies.

    Science.gov (United States)

    Savitzky, Alan H; Mori, Akira; Hutchinson, Deborah A; Saporito, Ralph A; Burghardt, Gordon M; Lillywhite, Harvey B; Meinwald, Jerrold

    2012-09-01

    Chemical defenses are widespread among animals, and the compounds involved may be either synthesized from nontoxic precursors or sequestered from an environmental source. Defensive sequestration has been studied extensively among invertebrates, but relatively few examples have been documented among vertebrates. Nonetheless, the number of described cases of defensive sequestration in tetrapod vertebrates has increased recently and includes diverse lineages of amphibians and reptiles (including birds). The best-known examples involve poison frogs, but other examples include natricine snakes that sequester toxins from amphibians and two genera of insectivorous birds. Commonalities among these diverse taxa include the combination of consuming toxic prey and exhibiting some form of passive defense, such as aposematism, mimicry, or presumptive death-feigning. Some species exhibit passive sequestration, in which dietary toxins simply require an extended period of time to clear from the tissues, whereas other taxa exhibit morphological or physiological specializations that enhance the uptake, storage, and/or delivery of exogenous toxins. It remains uncertain whether any sequestered toxins of tetrapods bioaccumulate across multiple trophic levels, but multitrophic accumulation seems especially likely in cases involving consumption of phytophagous or mycophagous invertebrates and perhaps consumption of poison frogs by snakes. We predict that additional examples of defensive toxin sequestration in amphibians and reptiles will be revealed by collaborations between field biologists and natural product chemists. Candidates for future investigation include specialized predators on mites, social insects, slugs, and toxic amphibians. Comprehensive studies of the ecological, evolutionary, behavioral, and regulatory aspects of sequestration will require teams of ecologists, systematists, ethologists, physiologists, molecular biologists, and chemists. The widespread occurrence of

  4. A transcriptomic analysis of gene expression in the venom gland of the snake Bothrops alternatus (urutu

    Directory of Open Access Journals (Sweden)

    Menossi Marcelo

    2010-10-01

    Full Text Available Abstract Background The genus Bothrops is widespread throughout Central and South America and is the principal cause of snakebite in these regions. Transcriptomic and proteomic studies have examined the venom composition of several species in this genus, but many others remain to be studied. In this work, we used a transcriptomic approach to examine the venom gland genes of Bothrops alternatus, a clinically important species found in southeastern and southern Brazil, Uruguay, northern Argentina and eastern Paraguay. Results A cDNA library of 5,350 expressed sequence tags (ESTs was produced and assembled into 838 contigs and 4512 singletons. BLAST searches of relevant databases showed 30% hits and 70% no-hits, with toxin-related transcripts accounting for 23% and 78% of the total transcripts and hits, respectively. Gene ontology analysis identified non-toxin genes related to general metabolism, transcription and translation, processing and sorting, (polypeptide degradation, structural functions and cell regulation. The major groups of toxin transcripts identified were metalloproteinases (81%, bradykinin-potentiating peptides/C-type natriuretic peptides (8.8%, phospholipases A2 (5.6%, serine proteinases (1.9% and C-type lectins (1.5%. Metalloproteinases were almost exclusively type PIII proteins, with few type PII and no type PI proteins. Phospholipases A2 were essentially acidic; no basic PLA2 were detected. Minor toxin transcripts were related to L-amino acid oxidase, cysteine-rich secretory proteins, dipeptidylpeptidase IV, hyaluronidase, three-finger toxins and ohanin. Two non-toxic proteins, thioredoxin and double-specificity phosphatase Dusp6, showed high sequence identity to similar proteins from other snakes. In addition to the above features, single-nucleotide polymorphisms, microsatellites, transposable elements and inverted repeats that could contribute to toxin diversity were observed. Conclusions Bothrops alternatus venom gland

  5. Oral microbiota of Brazilian captive snakes

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    MG Fonseca

    2009-01-01

    Full Text Available The present work aimed to determine the oral microbiotic composition of snakes from São José do Rio Preto city, São Paulo State, Brazil. Ten snake species, comprising the families Boidae, Colubridae, Elapidae and Viperidae, were submitted to microbiological examination of their oral cavity, which indicated positivity for all buccal samples. Gram-negative bacilli, gram-negative cocci bacilli, gram-positive bacilli and gram-positive cocci were isolated from the snakes. Among isolated bacterium species, the occurrence of coagulase-negative staphylococci in the buccal cavity of Crotalus durissus (Viperiade, Eunectes murinus (Boidae, Mastigodryas bifossatus (Colubridae and Bacillus subtilis, common to oral cavity of Bothrops alternatus (Viperidae and Phalotris mertensi (Colubridae, was detected. It was observed higher diversity of isolated bacteria from the oral cavity of Micrurus frontalis (Elapidae and Philodryas nattereri (Colubridae, as well as the prevalence of gram-positive baccillus and gram-positive cocci. The composition of the oral microbiota of the studied snakes, with or without inoculating fangs, is diverse and also related to the formation of abscesses at the bite site in the victims of the ophidian accidents, and to pathogenic processes in the snakes that host these microorganisms.

  6. Pelagic sea snakes dehydrate at sea.

    Science.gov (United States)

    Lillywhite, Harvey B; Sheehy, Coleman M; Brischoux, François; Grech, Alana

    2014-05-07

    Secondarily marine vertebrates are thought to live independently of fresh water. Here, we demonstrate a paradigm shift for the widely distributed pelagic sea snake, Hydrophis (Pelamis) platurus, which dehydrates at sea and spends a significant part of its life in a dehydrated state corresponding to seasonal drought. Snakes that are captured following prolonged periods without rainfall have lower body water content, lower body condition and increased tendencies to drink fresh water than do snakes that are captured following seasonal periods of high rainfall. These animals do not drink seawater and must rehydrate by drinking from a freshwater lens that forms on the ocean surface during heavy precipitation. The new data based on field studies indicate unequivocally that this marine vertebrate dehydrates at sea where individuals may live in a dehydrated state for possibly six to seven months at a time. This information provides new insights for understanding water requirements of sea snakes, reasons for recent declines and extinctions of sea snakes and more accurate prediction for how changing patterns of precipitation might affect these and other secondarily marine vertebrates living in tropical oceans.

  7. Function of snake mobbing in spectral tarsiers.

    Science.gov (United States)

    Gursky, Sharon

    2006-04-01

    Numerous species are known for their tendency to approach and confront their predators as a group. This behavior is known as mobbing. Snakes seem to be one of the more consistent recipients of this type of predator-directed behavior. This paper explores individual differences (sex and age) in the mobbing behavior of the spectral tarsier toward live and model snakes. This study was conducted at Tangkoko Nature Reserve (Sulawesi, Indonesia) during 2003-2004. During this research, 11 natural mobbing events and 31 artificially induced mobbing events were observed. The mean number of individuals at a mobbing was 5.7. The duration of mobbing events was strongly correlated with the number of assembled mobbers. Adults were more likely than other age classes to participate in mobbings. Males were more likely than females to participate in mobbings. Mobbing groups often contained more than one adult male, despite the fact that no spectral tarsier group contains more than one adult male. No difference in body size between extragroup males and resident males was observed, refuting the "attract the mightier" hypothesis. The number of mobbers did not affect whether the tarsier or the snake retreated first, countering the "move-on" hypothesis. The "perception advertisement" hypothesis was tentatively supported, in that live snakes were rarely seen in the area following mobbing calls, in comparison to when tarsiers either ignored the snake or alarm call. Copyright 2006 Wiley-Liss, Inc.

  8. Severe Coagulopathy after Ingestion of "Snake Wine".

    Science.gov (United States)

    Moon, Jeong Mi; Chun, Byeong Jo

    2016-06-01

    This report describes a patient who developed coagulopathy after ingesting snake wine, which is an alcoholic libation containing an entire venomous snake. A 68-year-old man was admitted to the hospital 19 h after ingesting snake wine. The laboratory features upon admission included unmeasurable activated partial thromboplastin (aPTT) values, prolonged prothrombin time (PT) values, increased fibrinogen levels, modestly elevated fibrin degradation product and D-dimer values, uncorrected aPTT and PT values after a mixing test, and normal levels of aspartate transaminase and alanine transaminase. No pesticides, warfarin, or superwarfarin in the patient's blood or urine were detected. His coagulation profile normalized on the 6(th) day after admission after antivenom treatment. He was discharged 10 days later without sequelae. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: The physician should be aware that ingesting snake wine may lead to systemic envenomation. As for coagulopathy, which may develop by ingesting snake venom, related laboratory findings may differ from the features observed after direct envenomation by snakebite. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. Blood flow dynamics in the snake spectacle.

    Science.gov (United States)

    van Doorn, Kevin; Sivak, Jacob G

    2013-11-15

    The eyes of snakes are shielded beneath a layer of transparent integument referred to as the 'reptilian spectacle'. Well adapted to vision by virtue of its optical transparency, it nevertheless retains one characteristic of the integument that would otherwise prove detrimental to vision: its vascularity. Given the potential consequence of spectacle blood vessels on visual clarity, one might expect adaptations to have evolved that mitigate their negative impact. Earlier research demonstrated an adaptation to their spatial layout in only one species to reduce the vessels' density in the region serving the foveal and binocular visual fields. Here, we present a study of spectacle blood flow dynamics and provide evidence of a mechanism to mitigate the spectacle blood vessels' deleterious effect on vision by regulation of blood flow through them. It was found that when snakes are at rest and undisturbed, spectacle vessels undergo cycles of dilation and constriction, such that the majority of the time the vessels are fully constricted, effectively removing them from the visual field. When snakes are presented with a visual threat, spectacle vessels constrict and remain constricted for longer periods than occur during the resting cycles, thus guaranteeing the best possible visual capabilities in times of need. Finally, during the snakes' renewal phase when they are generating a new stratum corneum, the resting cycle is abolished, spectacle vessels remain dilated and blood flow remains strong and continuous. The significance of these findings in terms of the visual capabilities and physiology of snakes is discussed.

  10. Molecular detection of Toxoplasma gondii in snakes.

    Science.gov (United States)

    Nasiri, Vahid; Teymurzadeh, Shohreh; Karimi, Gholamreza; Nasiri, Mehdi

    2016-10-01

    Toxoplasma gondii, an obligate intracellular protozoan parasite, is responsible for one of the most common zoonotic parasitic diseases in almost all warm-blooded vertebrates worldwide, and it is estimated that about one-third of the world human population is chronically infected with this parasite. Little is known about the circulation of T. gondii in snakes and this study for the first time aimed to evaluate the infection rates of snakes by this parasite by PCR methods. The brain of 68 Snakes, that were collected between May 2012 and September 2015 and died after the hold in captivity, under which they were kept for taking poisons, were examined for the presence of this parasite. DNA was extracted and Nested-PCR method was carried out with two of pairs of primers to detect the 344 bp fragment of T. gondii GRA6 gene. Five positive nested-PCR products were directly sequenced in the forward and reverse directions by Sequetech Company (Mountain View, CA). T. gondii GRA6 gene were detected from 55 (80.88%) of 68 snakes brains. Sequencing of the GRA6 gene revealed 98-100% of similarity with T. gondii sequences deposited in GenBank. To our knowledge, this is the first study of molecular detection of T. gondii in snakes and our findings show a higher frequency of this organism among them. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Pelagic sea snakes dehydrate at sea

    Science.gov (United States)

    Lillywhite, Harvey B.; Sheehy, Coleman M.; Brischoux, François; Grech, Alana

    2014-01-01

    Secondarily marine vertebrates are thought to live independently of fresh water. Here, we demonstrate a paradigm shift for the widely distributed pelagic sea snake, Hydrophis (Pelamis) platurus, which dehydrates at sea and spends a significant part of its life in a dehydrated state corresponding to seasonal drought. Snakes that are captured following prolonged periods without rainfall have lower body water content, lower body condition and increased tendencies to drink fresh water than do snakes that are captured following seasonal periods of high rainfall. These animals do not drink seawater and must rehydrate by drinking from a freshwater lens that forms on the ocean surface during heavy precipitation. The new data based on field studies indicate unequivocally that this marine vertebrate dehydrates at sea where individuals may live in a dehydrated state for possibly six to seven months at a time. This information provides new insights for understanding water requirements of sea snakes, reasons for recent declines and extinctions of sea snakes and more accurate prediction for how changing patterns of precipitation might affect these and other secondarily marine vertebrates living in tropical oceans. PMID:24648228

  12. Conditional Cooperativity in Toxin-Antitoxin Regulation Prevents Random Toxin Activation and Promotes Fast Translational Recovery

    DEFF Research Database (Denmark)

    Cataudella, Ilaria; Trusina, Ala; Sneppen, Kim

    2012-01-01

    Many toxin–antitoxin (TA) loci are known to strongly repress their own transcription. This auto-inhibition is often called ‘conditional cooperativity’ as it relies on cooperative binding of TA complexes to operator DNA that occurs only when toxins are in a proper stoichiometric relationship...... with antitoxins. There has recently been an explosion of interest in TA systems due to their role in bacterial persistence, however the role of conditional cooperativity is still unclear. We reveal the biological function of conditional cooperativity by constructing a mathematical model of the well studied TA...... such that random induction of relBE is minimized. At the same time it enables quick removal of free toxin when the starvation is terminated....

  13. Curvilinear shapes and the snake detection hypothesis : An ERP study

    NARCIS (Netherlands)

    Van Strien, Jan W; Christiaans, Gerwin; Franken, Ingmar H A; Huijding, Jorg

    Consistent with the snake detection hypothesis, previous ERP studies have established a larger early posterior negativity (EPN) in response to pictures depicting snakes than to pictures depicting other creatures. Here, we examined to what extent the curvilinear shape of the snake's body drives the

  14. Venomous Snake Bite Injuries at Kitui District Hospital

    African Journals Online (AJOL)

    presentation patterns and treatments offered for snake bites at Kitui District Hospital, and to characterize the causative venomous snakes. Patients and methods. This was a prospective case series carried out over a period of 8 months. Patients presenting at the hospital with snake bites were included in the study. A pre set.

  15. A successful trap design for capturing large terrestrial snakes

    Science.gov (United States)

    Shirley J. Burgdorf; D. Craig Rudolph; Richard N. Conner; Daniel Saenz; Richard R. Schaefer

    2005-01-01

    Large scale trapping protocols for snakes can be expensive and require large investments of personnel and time. Typical methods, such as pitfall and small funnel traps, are not useful or suitable for capturing large snakes. A method was needed to survey multiple blocks of habitat for the Louisiana Pine Snake (Pituophis ruthveni), throughout its...

  16. Snake and staff symbolism in healing | Retief | Acta Theologica

    African Journals Online (AJOL)

    Since time immemorial the snake has been venerated as an enigmatic creature with supernatural powers. As a snake and staff symbol it is also traditionally associated with the healing arts, either as the single-snake attribute of Asclepius, or as the doublesnake attribute of Hermes. In this article the mythological basis for this ...

  17. Snakes in the Grass: Weaving Success for Everyone.

    Science.gov (United States)

    Ide, Janet L.

    2000-01-01

    Describes "Snakes in the Grass," a weaving project used with special needs students. Discusses the preliminary skill-building activities used, the process for creating the students' individual snakes, and the preparation and process for how the students wove the snakes. (CMK)

  18. Effect of Gating Modifier Toxins on Membrane Thickness: Implications for Toxin Effect on Gramicidin and Mechanosensitive Channels

    Directory of Open Access Journals (Sweden)

    Shin-Ho Chung

    2013-02-01

    Full Text Available Various gating modifier toxins partition into membranes and interfere with the gating mechanisms of biological ion channels. For example, GsMTx4 potentiates gramicidin and several bacterial mechanosensitive channels whose gating kinetics are sensitive to mechanical properties of the membrane, whereas binding of HpTx2 shifts the voltage-activity curve of the voltage-gated potassium channel Kv4.2 to the right. The detailed process by which the toxin partitions into membranes has been difficult to probe using molecular dynamics due to the limited time scale accessible. Here we develop a protocol that allows the spontaneous assembly of a polypeptide toxin into membranes in atomistic molecular dynamics simulations of tens of nanoseconds. The protocol is applied to GsMTx4 and HpTx2. Both toxins, released in water at the start of the simulation, spontaneously bind into the lipid bilayer within 50 ns, with their hydrophobic patch penetrated into the bilayer beyond the phosphate groups of the lipids. It is found that the bilayer is about 2 Å thinner upon the binding of a GsMTx4 monomer. Such a thinning effect of GsMTx4 on membranes may explain its potentiation effect on gramicidin and mechanosensitive channels.

  19. Effect of gating modifier toxins on membrane thickness: implications for toxin effect on gramicidin and mechanosensitive channels.

    Science.gov (United States)

    Chen, Rong; Chung, Shin-Ho

    2013-02-22

    Various gating modifier toxins partition into membranes and interfere with the gating mechanisms of biological ion channels. For example, GsMTx4 potentiates gramicidin and several bacterial mechanosensitive channels whose gating kinetics are sensitive to mechanical properties of the membrane, whereas binding of HpTx2 shifts the voltage-activity curve of the voltage-gated potassium channel Kv4.2 to the right. The detailed process by which the toxin partitions into membranes has been difficult to probe using molecular dynamics due to the limited time scale accessible. Here we develop a protocol that allows the spontaneous assembly of a polypeptide toxin into membranes in atomistic molecular dynamics simulations of tens of nanoseconds. The protocol is applied to GsMTx4 and HpTx2. Both toxins, released in water at the start of the simulation, spontaneously bind into the lipid bilayer within 50 ns, with their hydrophobic patch penetrated into the bilayer beyond the phosphate groups of the lipids. It is found that the bilayer is about 2 Å thinner upon the binding of a GsMTx4 monomer. Such a thinning effect of GsMTx4 on membranes may explain its potentiation effect on gramicidin and mechanosensitive channels.

  20. Production of Recombinant Human scFv Against Tetanus Toxin Heavy Chain by Phage Display Technology.

    Science.gov (United States)

    Khalili, Ehsan; Lakzaei, Mostafa; Rasaee, Mohhamad Javad; Aminian, Mahdi

    2015-10-01

    Tetanus, as a major cause of death in developing countries, is caused by tetanus neurotoxin. Recombinant antibodies against tetanus neurotoxin can be useful in tetanus management. Phage display of antibody fragments from immune human antibody libraries with single chain constructs combining the variable fragments (scFv) has been one of the most prominent technologies in antibody engineering. The aim of this study was the generation of a single chain fragment of variable region (scFv) library and selection of specific antibodies with high affinity against tetanus toxin. Immune human single chain fragment variable (HuscFv) antibody phagemid library was displayed on pIII of filamentous bacteriophage. Selection of scFv clones was performed against tetanus toxin antigens after three rounds of panning. The selected scFv clones were analyzed for inhibition of tetanus toxin binding to ganglioside GT1b. After the third round of panning, over 35 HuscFv phages specific for tetanus toxin were isolated from this library of which 15 clones were found to bind specifically to tetanus toxin. The selected HuscFv phages expressed as a soluble HuscFv peptide and some clones showed positive signals against tetanus toxin. We found that six HuscFv clones inhibit toxin binding to ganglioside GT1b. These selected antibodies can be used in the management of tetanus.

  1. Cross neutralization of coral snake venoms by commercial Australian snake antivenoms.

    Science.gov (United States)

    Ramos, Henrique Roman; Vassão, Ruth Camargo; de Roodt, Adolfo Rafael; Santos E Silva, Ed Carlos; Mirtschin, Peter; Ho, Paulo Lee; Spencer, Patrick Jack

    2017-01-01

    Although rare, coral snake envenomation is a serious health threat in Brazil, because of the highly neurotoxic venom and the scarcely available antivenom. The major bottleneck for antivenom production is the low availability of venom. Furthermore, the available serum is not effective against all coral snake species found in Brazil. An alternative to circumvent the lack of venom for serum production and the restricted protection of the actually available antivenom would be of great value. We compared the Brazilian coral snake and mono and polyvalent Australian antivenoms in terms of reactivity and protection. The immunoreactivity of venoms from 9 coral snakes species were assayed by ELISA and western blot using the Brazilian Micrurus and the Australian pentavalent as well as monovalent anti-Notechis, Oxyuranus and Pseudechis antivenoms. Neutralization assays were performed in mice, using 3 LD 50 of the venoms, incubated for 30 minutes with 100 μL of antivenom/animal. All the venoms reacted against the autologous and heterologous antivenoms. Nevertheless, the neutralization assays showed that the coral snake antivenom was only effective against M. corallinus, M. frontalis, M. fulvius, M. nigrocinctus and M. pyrrhocryptus venoms. On the other hand, the Australian pentavalent antivenom neutralized all venoms except the one from M. spixii. A combination of anti-Oxyuranus and Pseudechis monovalent sera, extended the protection to M. altirostris and, partially, to M. ibiboboca. By adding Notechis antivenom to this mixture, we obtained full protection against M. ibiboboca and partial neutralization against M. lemniscatus venoms. Our findings confirm the limited effectiveness of the Brazilian coral snake antivenom and indicate that antivenoms made from Australian snakes venoms are an effective alternative for coral snake bites in South America and also in the United States were coral snake antivenom production has been discontinued.

  2. Cross neutralization of Afro-Asian cobra and Asian krait venoms by a Thai polyvalent snake antivenom (Neuro Polyvalent Snake Antivenom.

    Directory of Open Access Journals (Sweden)

    Poh Kuan Leong

    Full Text Available BACKGROUND: Snake envenomation is a serious public health threat in the rural areas of Asian and African countries. To date, the only proven treatment for snake envenomation is antivenom therapy. Cross-neutralization of heterologous venoms by antivenom raised against venoms of closely related species has been reported. The present study examined the cross neutralizing potential of a newly developed polyvalent antivenom, termed Neuro Polyvalent Snake Antivenom (NPAV. NPAV was produced by immunization against 4 Thai elapid venoms. PRINCIPAL FINDINGS: In vitro neutralization study using mice showed that NPAV was able to neutralize effectively the lethality of venoms of most common Asiatic cobras (Naja spp., Ophiophagus hannah and kraits (Bungarus spp. from Southeast Asia, but only moderately to weakly effective against venoms of Naja from India subcontinent and Africa. Studies with several venoms showed that the in vivo neutralization potency of the NPAV was comparable to the in vitro neutralization potency. NPAV could also fully protect against N. sputatrix venom-induced cardio-respiratory depressant and neuromuscular blocking effects in anesthetized rats, demonstrating that the NPAV could neutralize most of the major lethal toxins in the Naja venom. CONCLUSIONS/SIGNIFICANCE: The newly developed polyvalent antivenom NPAV may find potential application in the treatment of elapid bites in Southeast Asia, especially Malaysia, a neighboring nation of Thailand. Nevertheless, the applicability of NPAV in the treatment of cobra and krait envenomations in Southeast Asian victims needs to be confirmed by clinical trials. The cross-neutralization results may contribute to the design of broad-spectrum polyvalent antivenom.

  3. Cross Neutralization of Afro-Asian Cobra and Asian Krait Venoms by a Thai Polyvalent Snake Antivenom (Neuro Polyvalent Snake Antivenom)

    Science.gov (United States)

    Leong, Poh Kuan; Sim, Si Mui; Fung, Shin Yee; Sumana, Khomvilai; Sitprija, Visith; Tan, Nget Hong

    2012-01-01

    Background Snake envenomation is a serious public health threat in the rural areas of Asian and African countries. To date, the only proven treatment for snake envenomation is antivenom therapy. Cross-neutralization of heterologous venoms by antivenom raised against venoms of closely related species has been reported. The present study examined the cross neutralizing potential of a newly developed polyvalent antivenom, termed Neuro Polyvalent Snake Antivenom (NPAV). NPAV was produced by immunization against 4 Thai elapid venoms. Principal Findings In vitro neutralization study using mice showed that NPAV was able to neutralize effectively the lethality of venoms of most common Asiatic cobras (Naja spp.), Ophiophagus hannah and kraits (Bungarus spp.) from Southeast Asia, but only moderately to weakly effective against venoms of Naja from India subcontinent and Africa. Studies with several venoms showed that the in vivo neutralization potency of the NPAV was comparable to the in vitro neutralization potency. NPAV could also fully protect against N. sputatrix venom-induced cardio-respiratory depressant and neuromuscular blocking effects in anesthetized rats, demonstrating that the NPAV could neutralize most of the major lethal toxins in the Naja venom. Conclusions/Significance The newly developed polyvalent antivenom NPAV may find potential application in the treatment of elapid bites in Southeast Asia, especially Malaysia, a neighboring nation of Thailand. Nevertheless, the applicability of NPAV in the treatment of cobra and krait envenomations in Southeast Asian victims needs to be confirmed by clinical trials. The cross-neutralization results may contribute to the design of broad-spectrum polyvalent antivenom. PMID:22679522

  4. Efficacy of Indian polyvalent snake antivenoms against Sri Lankan snake venoms: lethality studies or clinically focussed in vitro studies

    Science.gov (United States)

    Maduwage, Kalana; Silva, Anjana; O’Leary, Margaret A.; Hodgson, Wayne C.; Isbister, Geoffrey K.

    2016-01-01

    In vitro antivenom efficacy studies were compared to rodent lethality studies to test two Indian snake antivenoms (VINS and BHARAT) against four Sri Lankan snakes. In vitro efficacy was tested at venom concentrations consistent with human envenoming. Efficacy was compared statistically for one batch from each manufacturer where multiple vials were available. In binding studies EC50 for all VINS antivenoms were less than BHARAT for D. russelii [553 μg/mL vs. 1371 μg/mL;p = 0.016), but were greater for VINS antivenoms compared to BHARAT for N. naja [336 μg/mL vs. 70 μg/mL;p < 0.0001]. EC50 of both antivenoms was only slighty different for E. carinatus and B. caeruleus. For procoagulant activity neutralisation, the EC50 was lower for VINS compared to BHARAT - 60 μg/mL vs. 176 μg/mL (p < 0.0001) for Russell’s viper and 357 μg/mL vs. 6906μg/mL (p < 0.0001) for Saw-scaled viper. Only VINS antivenom neutralized in vitro neurotoxicity of krait venom. Both antivenoms partially neutralized cobra and didn’t neutralize Russell’s viper neurotoxicity. Lethality studies found no statistically significant difference in ED50 values between VINS and BHARAT antivenoms. VINS antivenoms appeared superior to BHARAT at concentrations equivalent to administering 10 vials antivenom, based on binding and neutralisation studies. Lethality studies were inconsistent suggesting rodent death may not measure relevant efficacy outcomes in humans. PMID:27231196

  5. Enhancement of toxin- and virus-neutralizing capacity of single-domain antibody fragments by N-glycosylation

    NARCIS (Netherlands)

    Harmsen, M.M.; Smits, C.B.; Fijten, H.P.D.

    2009-01-01

    Single-domain antibody fragments (VHHs) have several beneficial properties as compared to conventional antibody fragments. However, their small size complicates their toxin- and virus-neutralizing capacity. We isolated 27 VHHs binding Escherichia coli heat-labile toxin and expressed these in

  6. Snake Envenomation Causing Distant Tracheal Myonecrosis

    Directory of Open Access Journals (Sweden)

    Amina Khimani

    2013-01-01

    Full Text Available Snakebites are often believed to be poisonous. However, this is not always the case. In fact, each bite differs from snake to snake, depending on if the snake is poisonous and if there is envenomation. Venom in pit viper snakebites is often associated with local necrosis. The abundant literature selections and research articles justify local myonecrosis due to envenomation, but there is not much in the literature regarding myonecrosis at a site distant from the snakebite. We hereby present a case of a 42-year-old man who was transferred to our emergency department after a rattlesnake bit him twice. The patient, besides developing local myonecrosis at the site of the snakebite, developed necrosis of the scrotum as well as tracheal pressure myonecrosis at the site of the endotracheal tube balloon. In this review, we will attempt to discuss the myonecrosis pathophysiology and management related to the rattle snakebite.

  7. Proteomic characterization and comparison of venoms from two elapid snakes (Bungarus multicinctus and Naja atra) from China.

    Science.gov (United States)

    Shan, Lin-Lin; Gao, Jian-Fang; Zhang, Yan-Xia; Shen, Shan-Shan; He, Ying; Wang, Jin; Ma, Xiao-Mei; Ji, Xiang

    2016-04-14

    Bungarus multicinctus (many-banded krait) and Naja atra (Chinese cobra) are widely distributed and medically important venomous snakes in China; however, their venom proteomic profiles have not been fully compared. Here, we fractionated crude venoms and analyzed them using a combination of proteomic techniques. Three-finger toxins (3-FTx) and phospholipase A2 (PLA2) were most abundant in both species, respectively accounting for 32.6% and 66.4% of total B. multicinctus venom, and 84.3% and 12.2% of total N. atra venom. Venoms from these two species contained one common protein family and six less abundant species-specific protein families. The proteomic profiles of B. multicinctus and N. atra venoms and analysis of toxicological activity in mice suggested that 3-FTx and PLA2 are the major contributors to clinical symptoms caused by envenomation. The venoms differed in enzymatic activity, likely the result of inter-specific variation in the amount of related venom components. Antivenomics assessment revealed that a small number of venom components (3-FTxs and PLA2s in B. multicinctus, and 3-FTxs in N. atra) could not be immunocaptured completely, suggesting that we should pay attention to enhancing the immune response of these components in designing commercial antivenoms for B. multicinctus and N. atra. The proteomic profiles of venoms from two medically important snake species - B. multicinctus and N. atra - have been explored. Quantitative and qualitative differences are evident in both venoms when proteomic profiles and transcriptomic results are compared; this is a reminder that combined approaches are needed to explore the precise composition of snake venom. Two protein families (3-FTx and PLA2) of high abundance in these snake venoms are major players in the biochemical and pharmacological effects of envenomation. Elucidation of the proteomic profiles of these snake venoms is helpful in understanding composition-function relationships and will facilitate the

  8. Tolevamer, an anionic polymer, neutralizes toxins produced by the BI/027 strains of Clostridium difficile.

    Science.gov (United States)

    Hinkson, Paul L; Dinardo, Carol; DeCiero, Daniel; Klinger, Jeffrey D; Barker, Robert H

    2008-06-01

    Clostridium difficile-associated diarrhea (CDAD) is caused by the toxins the organism produces when it overgrows in the colon as a consequence of antibiotic depletion of normal flora. Conventional antibiotic treatment of CDAD increases the likelihood of recurrent disease by again suppressing normal bacterial flora. Tolevamer, a novel toxin-binding polymer, was developed to ameliorate the disease without adversely affecting normal flora. In the current study, tolevamer was tested for its ability to neutralize clostridial toxins produced by the epidemic BI/027 strains, thereby preventing toxin-mediated tissue culture cell rounding. The titers of toxin-containing C. difficile culture supernatants were determined using confluent cell monolayers, and then the supernatants were used in assays containing dilutions of tolevamer to determine the lowest concentration of tolevamer that prevented > or =90% cytotoxicity. Tolevamer neutralized toxins in the supernatants of all C. difficile strains tested. Specific antibodies against the large clostridial toxins TcdA and TcdB also neutralized the cytopathic effect, suggesting that tolevamer is specifically neutralizing these toxins and that the binary toxin (whose genes are carried by the BI/027 strains) is not a significant source of cytopathology against tissue culture cells in vitro.

  9. Isolation, characterization, cloning and expression of an alpha-neurotoxin from the venom of the Mexican coral snake Micrurus laticollaris (Squamata: Elapidae).

    Science.gov (United States)

    Carbajal-Saucedo, Alejandro; López-Vera, Estuardo; Bénard-Valle, Melisa; Smith, Eric N; Zamudio, Fernando; de Roodt, Adolfo R; Olvera-Rodríguez, Alejandro

    2013-05-01

    A new member of short chain α-neurotoxic protein family from venom of the Mexican coral snake, Micrurus laticollaris, was characterized. This protein, named MlatA1, possesses 61 amino acids with 8 conserved cysteine residues, sharing 30-91% sequence identity with other fully sequenced Micrurus toxins. MlatA1 (LD50i.v. = 0.064 mg/kg) antagonizes with both fetal and adult nicotinic acetylcholine receptor (nAChR) as well as α-7 neuronal nAChR in a dose-dependent way. Specific rabbit anti-Mlat serum (titer higher than 18,000) does not show any protective ability against this toxin, nevertheless it was able to recognize protein bands in six out of twelve Micrurus venoms showing the existence of two distinct antigenic groups for α-neurotoxins in North American coral snakes species. The MlatA1 gene was cloned and used to produce recombinant toxin (rMlatA1) that was recognized by rabbit anti-native toxin but was depleted of toxic activity. Copyright © 2013. Published by Elsevier Ltd.

  10. Respiratory Effects of Sarafotoxins from the Venom of Different Atractaspis Genus Snake Species

    Directory of Open Access Journals (Sweden)

    Stéphanie Malaquin

    2016-07-01

    Full Text Available Sarafotoxins (SRTX are endothelin-like peptides extracted from the venom of snakes belonging to the Atractaspididae family. A recent in vivo study on anesthetized and ventilated animals showed that sarafotoxin-b (SRTX-b, extracted from the venom of Atractaspis engaddensis, decreases cardiac output by inducing left ventricular dysfunction while sarafotoxin-m (SRTX-m, extracted from the venom of Atractaspis microlepidota microlepidota, induces right ventricular dysfunction with increased airway pressure. The aim of the present experimental study was to compare the respiratory effects of SRTX-m and SRTX-b. Male Wistar rats were anesthetized, tracheotomized and mechanically ventilated. They received either a 1 LD50 IV bolus of SRTX-b (n = 5 or 1 LD50 of SRTX-m (n = 5. The low-frequency forced oscillation technique was used to measure respiratory impedance. Airway resistance (Raw, parenchymal damping (G and elastance (H were determined from impedance data, before and 5 min after SRTX injection. SRTX-m and SRTX-b injections induced acute hypoxia and metabolic acidosis with an increased anion gap. Both toxins markedly increased Raw, G and H, but with a much greater effect of SRTX-b on H, which may have been due to pulmonary edema in addition to bronchoconstriction. Therefore, despite their structural analogy, these two toxins exert different effects on respiratory function. These results emphasize the role of the C-terminal extension in the in vivo effect of these toxins.

  11. CD28: Direct and Critical Receptor for Superantigen Toxins

    Directory of Open Access Journals (Sweden)

    Ziv Rotfogel

    2013-09-01

    Full Text Available Every adaptive immune response requires costimulation through the B7/CD28 axis, with CD28 on T-cells functioning as principal costimulatory receptor. Staphylococcal and streptococcal superantigen toxins hyperstimulate the T-cell-mediated immune response by orders of magnitude, inducing a lethal cytokine storm. We show that to elicit an inflammatory cytokine storm and lethality, superantigens must bind directly to CD28. Blocking access of the superantigen to its CD28 receptor with peptides mimicking the contact domains in either toxin or CD28 suffices to protect mice effectively from lethal shock. Our finding that CD28 is a direct receptor of superantigen toxins broadens the scope of microbial pathogen recognition mechanisms.

  12. Rho-modifying bacterial protein toxins from Photorhabdus species.

    Science.gov (United States)

    Jank, Thomas; Lang, Alexander E; Aktories, Klaus

    2016-06-15

    Photorhabdus bacteria live in symbiosis with entomopathogenic nematodes. The nematodes invade insect larvae, where they release the bacteria, which then produce toxins to kill the insects. Recently, the molecular mechanisms of some toxins from Photorhabdus luminescens and asymbiotica have been elucidated, showing that GTP-binding proteins of the Rho family are targets. The tripartite Tc toxin PTC5 from P. luminescens activates Rho proteins by ADP-ribosylation of a glutamine residue, which is involved in GTP hydrolysis, while PaTox from Photorhabdus asymbiotica inhibits the activity of GTPases by N-acetyl-glucosaminylation at tyrosine residues and activates Rho proteins indirectly by deamidation of heterotrimeric G proteins. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Drinking in snakes: resolving a biomechanical puzzle.

    Science.gov (United States)

    Cundall, David; Brainerd, Elizabeth L; Constantino, Joseph; Deufel, Alexandra; Grapski, Douglas; Kley, Nathan J

    2012-03-01

    Snakes have long been thought to drink with a two-phase buccal-pump mechanism, but observations that some snakes can drink without sealing the margins of their mouths suggest that buccal pumping may not be the only drinking mechanism used by snakes. Here, we report that some snakes appear to drink using sponge-like qualities of specific regions of the oropharyngeal and esophageal mucosa and sponge-compressing functions of certain muscles and bones of the head. The resulting mechanism allows them to transport water upward against the effects of gravity using movements much slower than those of many other vertebrates. To arrive at this model, drinking was examined in three snake species using synchronized ciné and electromyographic recordings of muscle activity and in a fourth species using synchronized video and pressure recordings. Functional data were correlated with a variety of anatomical features to test specific predictions of the buccal-pump model. The anatomical data suggest explanations for the lack of conformity between a buccal-pump model of drinking and the performance of the drinking apparatus in many species. Electromyographic data show that many muscles with major functions in feeding play minor roles in drinking and, conversely, some muscles with minor roles in feeding play major roles in drinking. Mouth sealing by either the tongue or mental scale, previously considered critical to drinking in snakes, is incidental to drinking performance in some species. The sponge mechanism of drinking may represent a macrostomatan exaptation of mucosal folds, the evolution of which was driven primarily by the demands of feeding. © 2012 WILEY PERIODICALS, INC.

  14. A novel in vitro potency assay of antisera against Thai Naja kaouthia based on nicotinic acetylcholine receptor binding

    OpenAIRE

    Ratanabanangkoon, Kavi; Simsiriwong, Pavinee; Pruksaphon, Kritsada; Tan, Kae Yi; Eursakun, Sukanya; Tan, Choo Hock; Chantrathonkul, Bunkuea; Wongwadhunyoo, Wongsakorn; Youngchim, Sirida; Tan, Nget Hong

    2017-01-01

    Snake envenomation is an important medical problem. One of the hurdles in antivenom development is the in vivo assay of antivenom potency which is expensive, gives variable results and kills many animals. We report a novel in vitro assay involving the specific binding of the postsynaptic neurotoxins (PSNTs) of elapid snakes with purified Torpedo californica nicotinic acetylcholine receptor (nAChR). The potency of an antivenom is determined by its antibody ability to bind and neutralize the PS...

  15. Inhibitory potential of important phytochemicals from Pergularia daemia (Forsk. chiov., on snake venom (Naja naja

    Directory of Open Access Journals (Sweden)

    S.T.V. Raghavamma

    2016-06-01

    Full Text Available Pergularia daemia (Forsk. chiov., is a milk weed of Asclepiadaceae family. In the present study β-sitosterol, β-amyrin, α-amyrin and lupeol were identified in the leaf by GC–MS. Molecular docking studies were performed to evaluate their activities on phospholipase A2 (PLA2 and l-amino acid oxidase enzymes which constituted a rich source in snake venoms (Naja naja. Snake venom Phospholipase A2 with PDB code 1A3D devoid of co-crystallized ligand was extracted from Protein Data Bank. Using Molegro Virtual Docker two cavities are formed by cocrystallization. l-Amino acid oxidase (PDB code 4E0V was a receptor model with a co-crystallized ligand FAD. Among the phytochemicals analysed, β-sitosterol displayed high affinity of binding to the active site regions of phospholipase A2 and l-amino acid oxidase, respectively. The affinity of binding was −125.939 and −157.521 kcal/mole identified by gold scores. α-Amyrin and β-amyrin had two hydrogen bond interactions with PLA2. Hence this study suggests that β-sitosterol identified in P. daemia can antagonize PLA2 and LAAO activities and forms a theoretical basis for the folk use of the plant against snake venom.

  16. Snakes of Zaire and Their Bites

    OpenAIRE

    CHIFUNDERA, Kusamba

    1990-01-01

    The ophidiological survey made in Zaire revealed the presence of 152 species of snakes included in 60 genera and in 8 families. The family Colubridae contains the largest number of genera (45) and species (97). Their geographical distribution shows that the eastern part of Kivu region contains a wild variety of species (90 species). The density of Zairean snakes has not yet been known. But in some localities like Kamanyola in the Kivu province, the density is as high as 80 individuals per squ...

  17. Cellular uptake of Clostridium botulinum C2 toxin requires oligomerization and acidification

    NARCIS (Netherlands)

    Barth, H; Blocker, D; Behlke, J; Bergsma-Schutter, W; Brisson, A; Benz, R; Aktories, K

    2000-01-01

    The actin-ADP-ribosylating binary Clostridium botulinum C2 toxin consists of two individual proteins, the binding/translocation component C2II and the enzyme component C2I. To elicit its cytotoxic action, C2II binds to a receptor on the cell surface and mediates cell entry of C2I via

  18. Detection of RTX toxin genes in gram-negative bacteria with a set of specific probes.

    Science.gov (United States)

    Kuhnert, P; Heyberger-Meyer, B; Burnens, A P; Nicolet, J; Frey, J

    1997-06-01

    The family of RTX (RTX representing repeats in the structural toxin) toxins is composed of several protein toxins with a characteristic nonapeptide glycine-rich repeat motif. Most of its members were shown to have cytolytic activity. By comparing the genetic relationships of the RTX toxin genes we established a set of 10 gene probes to be used for screening as-yet-unknown RTX toxin genes in bacterial species. The probes include parts of apxIA, apxIIA, and apxIIIA from Actinobacillus pleuropneumoniae, cyaA from Bordetella pertusis, frpA from Neisseria meningitidis, prtC from Erwinia chrysanthemi, hlyA and elyA from Escherichia coli, aaltA from Actinobacillus actinomycetemcomitans and lktA from Pasteurella haemolytica. A panel of pathogenic and nonpathogenic gram-negative bacteria were investigated for the presence of RTX toxin genes. The probes detected all known genes for RTX toxins. Moreover, we found potential RTX toxin genes in several pathogenic bacterial species for which no such toxins are known yet. This indicates that RTX or RTX-like toxins are widely distributed among pathogenic gram-negative bacteria. The probes generated by PCR and the hybridization method were optimized to allow broad-range screening for RTX toxin genes in one step. This included the binding of unlabelled probes to a nylon filter and subsequent hybridization of the filter with labelled genomic DNA of the strain to be tested. The method constitutes a powerful tool for the assessment of the potential pathogenicity of poorly characterized strains intended to be used in biotechnological applications. Moreover, it is useful for the detection of already-known or new RTX toxin genes in bacteria of medical importance.

  19. What killed Karl Patterson Schmidt? Combined venom gland transcriptomic, venomic and antivenomic analysis of the South African green tree snake (the boomslang), Dispholidus typus.

    Science.gov (United States)

    Pla, Davinia; Sanz, Libia; Whiteley, Gareth; Wagstaff, Simon C; Harrison, Robert A; Casewell, Nicholas R; Calvete, Juan J

    2017-04-01

    Non-front-fanged colubroid snakes comprise about two-thirds of extant ophidian species. The medical significance of the majority of these snakes is unknown, but at least five species have caused life-threatening or fatal human envenomings. However, the venoms of only a small number of species have been explored. A combined venomic and venom gland transcriptomic approach was employed to characterise of venom of Dispholidus typus (boomslang), the snake that caused the tragic death of Professor Karl Patterson Schmidt. The ability of CroFab™ antivenom to immunocapture boomslang venom proteins was investigated using antivenomics. Transcriptomic-assisted proteomic analysis identified venom proteins belonging to seven protein families: three-finger toxin (3FTx); phospholipase A2 (PLA2); cysteine-rich secretory proteins (CRISP); snake venom (SV) serine proteinase (SP); C-type lectin-like (CTL); SV metalloproteinases (SVMPs); and disintegrin-like/cysteine-rich (DC) proteolytic fragments. CroFab™ antivenom efficiently immunodepleted some boomslang SVMPs. The present work is the first to address the overall proteomic profile of D. typus venom. This study allowed us to correlate the toxin composition with the toxic activities of the venom. The antivenomic analysis suggested that the antivenom available at the time of the unfortunate accident could have exhibited at least some immunoreactivity against the boomslang SVMPs responsible for the disseminated intravascular coagulation syndrome that caused K.P. Schmidt's fatal outcome. This study may stimulate further research on other non-front-fanged colubroid snake venoms capable of causing life-threatening envenomings to humans, which in turn should contribute to prevent fatal human accidents, such as that unfortunately suffered by K.P. Schmidt. Copyright © 2017 The Author(s). Published by Elsevier B.V. All rights reserved.

  20. A Heterologous Multiepitope DNA Prime/Recombinant Protein Boost Immunisation Strategy for the Development of an Antiserum against Micrurus corallinus (Coral Snake) Venom.

    Science.gov (United States)

    Ramos, Henrique Roman; Junqueira-de-Azevedo, Inácio de Loiola M; Novo, Juliana Branco; Castro, Karen; Duarte, Clara Guerra; Machado-de-Ávila, Ricardo A; Chavez-Olortegui, Carlos; Ho, Paulo Lee

    2016-03-01

    Envenoming by coral snakes (Elapidae: Micrurus), although not abundant, represent a serious health threat in the Americas, especially because antivenoms are scarce. The development of adequate amounts of antielapidic serum for the treatment of accidents caused by snakes like Micrurus corallinus is a challenging task due to characteristics such as low venom yield, fossorial habit, relatively small sizes and ophiophagous diet. These features make it difficult to capture and keep these snakes in captivity for venom collection. Furthermore, there are reports of antivenom scarcity in USA, leading to an increase in morbidity and mortality, with patients needing to be intubated and ventilated while the toxin wears off. The development of an alternative method for the production of an antielapidic serum, with no need for snake collection and maintenance in captivity, would be a plausible solution for the antielapidic serum shortage. In this work we describe the mapping, by the SPOT-synthesis technique, of potential B-cell epitopes from five putative toxins from M. corallinus, which were used to design two multiepitope DNA strings for the genetic immunisation of female BALB/c mice. Results demonstrate that sera obtained from animals that were genetically immunised with these multiepitope constructs, followed by booster doses of recombinant proteins lead to a 60% survival in a lethal dose neutralisation assay. Here we describe that the genetic immunisation with a synthetic multiepitope gene followed by booster doses with recombinant protein is a promising approach to develop an alternative antielapidic serum against M. corallinus venom without the need of collection and the very challenging maintenance of these snakes in captivity.

  1. A Heterologous Multiepitope DNA Prime/Recombinant Protein Boost Immunisation Strategy for the Development of an Antiserum against Micrurus corallinus (Coral Snake Venom.

    Directory of Open Access Journals (Sweden)

    Henrique Roman Ramos

    2016-03-01

    Full Text Available Envenoming by coral snakes (Elapidae: Micrurus, although not abundant, represent a serious health threat in the Americas, especially because antivenoms are scarce. The development of adequate amounts of antielapidic serum for the treatment of accidents caused by snakes like Micrurus corallinus is a challenging task due to characteristics such as low venom yield, fossorial habit, relatively small sizes and ophiophagous diet. These features make it difficult to capture and keep these snakes in captivity for venom collection. Furthermore, there are reports of antivenom scarcity in USA, leading to an increase in morbidity and mortality, with patients needing to be intubated and ventilated while the toxin wears off. The development of an alternative method for the production of an antielapidic serum, with no need for snake collection and maintenance in captivity, would be a plausible solution for the antielapidic serum shortage.In this work we describe the mapping, by the SPOT-synthesis technique, of potential B-cell epitopes from five putative toxins from M. corallinus, which were used to design two multiepitope DNA strings for the genetic immunisation of female BALB/c mice. Results demonstrate that sera obtained from animals that were genetically immunised with these multiepitope constructs, followed by booster doses of recombinant proteins lead to a 60% survival in a lethal dose neutralisation assay.Here we describe that the genetic immunisation with a synthetic multiepitope gene followed by booster doses with recombinant protein is a promising approach to develop an alternative antielapidic serum against M. corallinus venom without the need of collection and the very challenging maintenance of these snakes in captivity.

  2. The status of taxonomy and venom in sea snakes

    DEFF Research Database (Denmark)

    Redsted Rasmussen, Arne; Sanders, Kate L.

    2017-01-01

    The status of taxonomy and venom in sea snakesArne R Rasmussen1, Kate L Sanders21 The Royal Danish Academy of Fine Arts, School of Architecture, Design & Conservation, Copenhagen, Denmark2 School of Earth and Environmental Sciences, University of Adelaide, Adelaide, South Australia 5000, Australia......Sea snakes form two aquatic groups of snakes with a flat vertically paddle-form tail (sea kraits and viviparous sea snakes). Sea snakes belong to the same family Elapidae, which also includes the terrestrial mambas, cobra, kraits, taipan and brown snake. All elapids are characterized by the anterior position...... of the poison-fangs on the maxillary bone (proteroglyphous). Globally there are some 70 species of sea snake found in the tropical and subtropical waters of the Indian Ocean and the Pacific Ocean. Most species are found in the Indo-Malayan Archipelago, the China Sea, Indonesia, and the Australian region...

  3. Antiradiation Vaccine: Immunological neutralization of Radiation Toxins at Acute Radiation Syndromes.

    Science.gov (United States)

    Popov, Dmitri; Maliev, Slava

    Introduction: Current medical management of the Acute Radiation Syndromes (ARS) does not include immune prophylaxis based on the Antiradiation Vaccine. Existing principles for the treatment of acute radiation syndromes are based on the replacement and supportive therapy. Haemotopoietic cell transplantation is recomended as an important method of treatment of a Haemopoietic form of the ARS. Though in the different hospitals and institutions, 31 pa-tients with a haemopoietic form have previously undergone transplantation with stem cells, in all cases(100%) the transplantants were rejected. Lethality rate was 87%.(N.Daniak et al. 2005). A large amount of biological substances or antigens isolated from bacterias (flagellin and derivates), plants, different types of venom (honeybees, scorpions, snakes) have been studied. This biological active substances can produce a nonspecific stimulation of immune system of mammals and protect against of mild doses of irradiation. But their radioprotection efficacy against high doses of radiation were not sufficient. Relative radioprotection characteristics or adaptive properties of antioxidants were expressed only at mild doses of radiation. However antioxidants demonstrated a very low protective efficacy at high doses of radiation. Some ex-periments demonstrated even a harmful effect of antioxidants administered to animals that had severe forms of the ARS. Only Specific Radiation Toxins roused a specific antigenic stim-ulation of antibody synthesis. An active immunization by non-toxic doses of radiation toxins includes a complex of radiation toxins that we call the Specific Radiation Determinant (SRD). Immunization must be provided not less than 24 days before irradiation and it is effective up to three years and more. Active immunization by radiation toxins significantly reduces the mortality rate (100%) and improves survival rate up to 60% compare with the 0% sur-vival rate among the irradiated animals in control groups

  4. Structural Determinants for Antitoxin Identity and Insulation of Cross Talk between Homologous Toxin-Antitoxin Systems.

    Science.gov (United States)

    Walling, Lauren R; Butler, J Scott

    2016-12-15

    Toxin-antitoxin (TA) systems are ubiquitous in bacteria and archaea, where they play a pivotal role in the establishment and maintenance of dormancy. Under normal growth conditions, the antitoxin neutralizes the toxin. However, under conditions of stress, such as nutrient starvation or antibiotic treatment, cellular proteases degrade the antitoxin, and the toxin functions to arrest bacterial growth. We characterized the specificity determinants of the interactions between VapB antitoxins and VapC toxins from nontypeable Haemophilus influenzae (NTHi) in an effort to gain a better understanding of how antitoxins control toxin activity and bacterial persistence. We studied truncated and full-length antitoxins with single amino acid mutations in the toxin-binding domain. Coexpressing the toxin and antitoxin in Escherichia coli and measuring bacterial growth by dilution plating assayed the ability of the mutant antitoxins to neutralize the toxin. Our results identified two single amino acid residues (W48 and F52) in the C-terminal region of the VapB2 antitoxin necessary for its ability to neutralize its cognate VapC2 toxin. Additionally, we attempted to alter the specificity of VapB1 by making a mutation that would allow it to neutralize its noncognate toxin. A mutation in VapB1 to contain the tryptophan residue identified herein as important in the VapB2-VapC2 interaction resulted in a VapB1 mutant (the T47W mutant) that binds to and neutralizes both its cognate VapC1 and noncognate VapC2 toxins. This represents the first example of a single mutation causing relaxed specificity in a type II antitoxin. Toxin-antitoxin systems are of particular concern in pathogenic organisms, such as nontypeable Haemophilus influenzae, as they can elicit dormancy and persistence, leading to chronic infections and failure of antibiotic treatment. Despite the importance of the TA interaction, the specificity determinants for VapB-VapC complex formation remain uncharacterized. Thus, our

  5. Toxin-mediated effects on the innate mucosal defenses: implications for enteric vaccines

    DEFF Research Database (Denmark)

    Glenn, Gregory M; Francis, David H; Danielsen, E Michael

    2009-01-01

    mucosal barrier as a key step in enteric pathogen survival. We review key observations relevant to the roles of LT and cholera toxin in protective immunity and the effects of these toxins on innate mucosal defenses. We suggest either that toxin-mediated fluid secretion mechanically disrupts the mucus...... layer or that toxins interfere with innate mucosal defenses by other means. Such a breach gives pathogens access to the enterocyte, leading to binding and pathogenicity by enterotoxigenic E. coli (ETEC) and other organisms. Given the common exposure to LT(+) ETEC by humans visiting or residing...... in regions of endemicity, barrier disruption should frequently render the gut vulnerable to ETEC and other enteric infections. Conversely, toxin immunity would be expected to block this process by protecting the innate mucosal barrier. Years ago, Peltola et al. (Lancet 338:1285-1289, 1991) observed...

  6. T-2 Toxin-induced Toxicity in Pregnant Mice and Rats

    Directory of Open Access Journals (Sweden)

    Shinya Sehata

    2008-11-01

    Full Text Available T-2 toxin is a cytotoxic secondary fungal metabolite that belongs to the trichothecene mycotoxin family. This mycotoxin is a well known inhibitor of protein synthesis through its high binding affinity to peptidyl transferase, which is an integral part of the ribosomal 60s subunit, and it also inhibits the synthesis of DNA and RNA, probably secondary to the inhibition of protein synthesis. In addition, T-2 toxin is said to induce apoptosis in many types of cells bearing high proliferating activity. T-2 toxin readily passes the placenta and is distributed to embryo/fetal tissues, which include many component cells bearing high proliferating activity. This paper reviews the reported data related to T-2 toxin-induced maternal and fetal toxicities in pregnant mice and rats. The mechanisms of T-2 toxin-induced apoptosis in maternal and fetal tissues are also discussed in this paper.

  7. Sea snake harvest in the gulf of Thailand.

    Science.gov (United States)

    Van Cao, Nguyen; Thien Tao, Nguyen; Moore, Amelia; Montoya, Alfred; Redsted Rasmussen, Arne; Broad, Kenneth; Voris, Harold K; Takacs, Zoltan

    2014-12-01

    Conservation of sea snakes is virtually nonexistent in Asia, and its role in human-snake interactions in terms of catch, trade, and snakebites as an occupational hazard is mostly unexplored. We collected data on sea snake landings from the Gulf of Thailand, a hotspot for sea snake harvest by squid fishers operating out of the ports of Song Doc and Khanh Hoi, Ca Mau Province, Vietnam. The data were collected during documentation of the steps of the trading process and through interviewers with participants in the trade. Squid vessels return to ports once per lunar synodic cycle and fishers sell snakes to merchants who sort, package, and ship the snakes to various destinations in Vietnam and China for human consumption and as a source of traditional remedies. Annually, 82 t, roughly equal to 225,500 individuals, of live sea snakes are brought to ports. To our knowledge, this rate of harvest constitutes one of the largest venomous snake and marine reptile harvest activities in the world today. Lapemis curtus and Hydrophis cyanocinctus constituted about 85% of the snake biomass, and Acalyptophis peronii, Aipysurus eydouxii, Hydrophis atriceps, H. belcheri, H. lamberti, and H. ornatus made up the remainder. Our results establish a quantitative baseline for characteristics of catch, trade, and uses of sea snakes. Other key observations include the timing of the trade to the lunar cycle, a decline of sea snakes harvested over the study period (approximately 30% decline in mass over 4 years), and the treatment of sea snake bites with rhinoceros horn. Emerging markets in Southeast Asia drive the harvest of venomous sea snakes in the Gulf of Thailand and sea snake bites present a potentially lethal occupational hazard. We call for implementation of monitoring programs to further address the conservation implications of this large-scale marine reptile exploitation. © 2014 Society for Conservation Biology.

  8. Born Knowing: Tentacled Snakes Innately Predict Future Prey Behavior

    Science.gov (United States)

    Catania, Kenneth C.

    2010-01-01

    Background Aquatic tentacled snakes (Erpeton tentaculatus) can take advantage of their prey's escape response by startling fish with their body before striking. The feint usually startles fish toward the snake's approaching jaws. But when fish are oriented at a right angle to the jaws, the C-start escape response translates fish parallel to the snake's head. To exploit this latter response, snakes must predict the future location of the fish. Adult snakes can make this prediction. Is it learned, or are tentacled snakes born able to predict future fish behavior? Methods and Findings Laboratory-born, naïve snakes were investigated as they struck at fish. Trials were recorded at 250 or 500 frames per second. To prevent learning, snakes were placed in a water container with a clear transparency sheet or glass bottom. The chamber was placed over a channel in a separate aquarium with fish below. Thus snakes could see and strike at fish, without contact. The snake's body feint elicited C-starts in the fish below the transparency sheet, allowing strike accuracy to be quantified in relationship to the C-starts. When fish were oriented at a right angle to the jaws, naïve snakes biased their strikes to the future location of the escaping fish's head, such that the snake's jaws and the fish's translating head usually converged. Several different types of predictive strikes were observed. Conclusions The results show that some predators have adapted their nervous systems to directly compensate for the future behavior of prey in a sensory realm that usually requires learning. Instead of behavior selected during their lifetime, newborn tentacled snakes exhibit behavior that has been selected on a different scale—over many generations. Counter adaptations in fish are not expected, as tentacled snakes are rare predators exploiting fish responses that are usually adaptive. PMID:20585384

  9. The upper cretaceous snake Dinilysia patagonica Smith-Woodward, 1901, and the crista circumfenestralis of snakes.

    Science.gov (United States)

    Palci, Alessandro; Caldwell, Michael W

    2014-10-01

    Studies on the phylogenetic relationships of snakes and lizards are plagued by problematic characterizations of anatomy that are then used to define characters and states in taxon-character matrices. State assignments and character descriptions must be clear characterizations of observable anatomy and topological relationships if homologies are to be hypothesized. A supposed homology among snakes, not observed in lizards, is the presence of a crista circumfenestralis (CCF), a system of bony crests surrounding the fenestra ovalis and lateral aperture of the recessus scalae tympani. We note that there are some fossil and extant snakes that lack a CCF, and some extant lizards that possess a morphological equivalent. The phylogenetically important upper Cretaceous fossil snake Dinilysia patagonica has been interpreted by different authors as either having or lacking a CCF. These conflicting results for Dinilysia were tested by re-examining the morphology of the otic region in a large sample of snakes and lizards. An unambiguous criterion arising from the test of topology is used to define the presence of a CCF: the enclosure of the ventral margin of the juxtastapedial recess by flanges of the otoccipital (crista tuberalis and crista interfenestralis) that extend forward to contact the posterior margin of the prootic. According to this criterion D. patagonica does not possess a CCF, therefore, this anatomical feature must have arisen later during the evolution of snakes. Copyright © 2014 Wiley Periodicals, Inc.

  10. Positive Darwinian selection results in resistance to cardioactive toxins in true toads (Anura: Bufonidae).

    Science.gov (United States)

    Moore, David J; Halliday, Damien C T; Rowell, David M; Robinson, Anthony J; Keogh, J Scott

    2009-08-23

    Members of the Family Bufonidae, true toads, are famous for their endogenously synthesized cardioactive steroids that serve as defensive toxins. Evolution of resistance to these toxins is not understood. We sequenced a key region of the toxin's binding site in the Na(+)/K(+) ATPase for relevant taxa representing Hyloidea (including bufonids), Ranoidea and Archaeobatrachia and tested for positive selection in a phylogenetic context. Bufonidae were distinct from other Hyloidea at 4-6 of 12 sites and, with one exception, had a homologous amino acid sequence. Melanophryniscus stelzneri had a distinct sequence, consistent with other independent evidence for a differentiated toxin. Tests within Bufonidae detected positive selection within the binding region, providing, to our knowledge, the first evidence of this type for positive selection within Amphibia. There was no evidence for positive selection on Bufonidae or M. stelzneri lineages. Sequence change in Leptodactylus ocellatus, a leptodactylid predator of Bufonidae, provides a molecular basis for predator resistance possibly associated with gene duplication.

  11. Vaccination against Clostridium difficile using toxin fragments: Observations and analysis in animal models.

    Science.gov (United States)

    Spencer, Janice; Leuzzi, Rosanna; Buckley, Anthony; Irvine, June; Candlish, Denise; Scarselli, Maria; Douce, Gillian R

    2014-01-01

    Clostridium difficile is a major cause of antibiotic associated diarrhea. Recently, we have shown that effective protection can be mediated in hamsters through the inclusion of specific recombinant fragments from toxin A and B in a systemically delivered vaccine. Interestingly while neutralizing antibodies to the binding domains of both toxin A and B are moderately protective, enhanced survival is observed when fragments from the glucosyltransferase region of toxin B replace those from the binding domain of this toxin. In this addendum, we discuss additional information that has been derived from such vaccination studies. This includes observations on efficacy and cross-protection against different ribotypes mediated by these vaccines and the challenges that remain for a vaccine which prevents clinical symptoms but not colonization. The use and value of vaccination both in the prevention of infection and for treatment of disease relapse will be discussed.

  12. Cytotoxicity of the Bacillus thuringiensis Cry4B toxin is mediated by the cadherin receptor BT-R₃ of Anopheles gambiae.

    Science.gov (United States)

    Ibrahim, Mohamed A; Griko, Natalya B; Bulla, Lee A

    2013-07-01

    We demonstrate for the first time the selective cytotoxicity of Bacillus thuringiensis subsp. israelensis Cry4B toxin mediated by BT-R₃ using a cell-based system, which employs High Five insect cells stably expressing BT-R₃. Discovery and validation of BT-R₃ as the Cry4B receptor was accomplished using a web-based computational pipeline platform that facilitates high-throughput insecticidal target identification utilizing the Anopheles gambiae genome. Once the Cry4B toxin binds to the BT-R₃ receptor, a cell death pathway is manifested by sequential cytological changes that include membrane blebbing, cell swelling and lysis. Cry4B toxin associates with cell membrane in both oligomeric and monomeric forms. Monomeric toxin binds specifically to BT-R₃ whereas oligomer interacts with cell membrane non-specifically. Cytotoxicity and cell death are the direct result of binding of toxin monomer to BT-R₃. The oligomeric form of Cry4B toxin is not involved in cell death. Both the location of the toxin-binding region within BT-R₃ and its structural motif are critical to the binding affinity and specificity of the toxin. The toxin-binding region of BT-R₃ appears to be located in EC11, the most membrane proximal EC module within the extracellular domain. It is characterized by the presence of two highly conserved amino acid sequences within their N- and C-termini that flank EC11. These sequences represent signature motifs that mark the toxin-binding function in BT-R₃. The two sequences form two adjacent β-strands within the β-barrel of EC11, the positioning of which is a hallmark of all Cry toxin receptors thus far reported.