201
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Van Vaerenbergh M, Debyser G, Devreese B, de Graaf DC. Exploring the hidden honeybee (Apis mellifera) venom proteome by integrating a combinatorial peptide ligand library approach with FTMS. J Proteomics 2014; 99:169-78. [PMID: 24606962 DOI: 10.1016/j.jprot.2013.04.039] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Revised: 04/22/2013] [Accepted: 04/28/2013] [Indexed: 10/25/2022]
Abstract
UNLABELLED At present, 30 compounds have been described in the venom of the honeybee, and 16 of them were confirmed by mass spectrometry. Previous studies typically combined 2-D PAGE with MALDI-TOF/TOF MS, a technology which now appears to lack sensitivity to detect additional venom compounds. Here, we report an in-depth study of the honeybee venom proteome using a combinatorial peptide ligand library sample pretreatment to enrich for minor components followed by shotgun LC-FT-ICR MS analysis. This strategy revealed an unexpectedly rich venom composition: in total 102 proteins and peptides were found, with 83 of them never described in bee venom samples before. Based on their predicted function and subcellular location, the proteins could be divided into two groups. A group of 33 putative toxins is proposed to contribute to venom activity by exerting toxic functions or by playing a role in social immunity. The other group, considered as venom trace molecules, appears to be secreted for their functions in the extracellular space, or is unintentionally secreted by the venom gland cells due to insufficient protein recycling or co-secretion with other compounds. In conclusion, our approach allowed to explore the hidden honeybee venom proteome and extended the list of potential venom allergens. BIOLOGICAL SIGNIFICANCE This study dug deeper into the complex honeybee venom proteome than ever before by applying a highly performing sample pretreatment and mass spectrometric technology. We present putative biological functions for all identified compounds, largely extending our knowledge of the venom toxicity. In addition, this study offers a long list of potential new venom allergens.
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Affiliation(s)
| | - Griet Debyser
- Laboratory of Protein Biochemistry and Biomolecular Engineering, Ghent University, K.L. Ledeganckstraat 35, B-9000 Ghent, Belgium
| | - Bart Devreese
- Laboratory of Protein Biochemistry and Biomolecular Engineering, Ghent University, K.L. Ledeganckstraat 35, B-9000 Ghent, Belgium
| | - Dirk C de Graaf
- Laboratory of Zoophysiology, Ghent University, K.L. Ledeganckstraat 35, B-9000 Ghent, Belgium
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202
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Brahma RK, McCleary RJR, Kini RM, Doley R. Venom gland transcriptomics for identifying, cataloging, and characterizing venom proteins in snakes. Toxicon 2014; 93:1-10. [PMID: 25448392 DOI: 10.1016/j.toxicon.2014.10.022] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Accepted: 10/27/2014] [Indexed: 01/13/2023]
Abstract
Snake venoms are cocktails of protein toxins that play important roles in capture and digestion of prey. Significant qualitative and quantitative variation in snake venom composition has been observed among and within species. Understanding these variations in protein components is instrumental in interpreting clinical symptoms during human envenomation and in searching for novel venom proteins with potential therapeutic applications. In the last decade, transcriptomic analyses of venom glands have helped in understanding the composition of various snake venoms in great detail. Here we review transcriptomic analysis as a powerful tool for understanding venom profile, variation and evolution.
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Affiliation(s)
- Rajeev Kungur Brahma
- Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur 784 028, Assam, India
| | - Ryan J R McCleary
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, Singapore
| | - R Manjunatha Kini
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, Singapore; Department of Biochemistry, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA, USA; University of South Australia, School of Pharmacy and Medical Sciences, Adelaide, South Australia 5001, Australia
| | - Robin Doley
- Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur 784 028, Assam, India.
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203
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Zelanis A, Keiji Tashima A. Unraveling snake venom complexity with ‘omics’ approaches: Challenges and perspectives. Toxicon 2014; 87:131-4. [DOI: 10.1016/j.toxicon.2014.05.011] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Revised: 04/14/2014] [Accepted: 05/07/2014] [Indexed: 11/29/2022]
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204
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Trummal K, Aaspõllu A, Tõnismägi K, Samel M, Subbi J, Siigur J, Siigur E. Phosphodiesterase from Vipera lebetina venom - structure and characterization. Biochimie 2014; 106:48-55. [PMID: 25079051 DOI: 10.1016/j.biochi.2014.07.020] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Accepted: 07/19/2014] [Indexed: 11/24/2022]
Abstract
Nucleases and phosphatases are ubiquitous but mostly marginal components of snake venoms. These proteins have been studied quite extensively but up to now no data regarding their amino acid sequences confirmed at protein level have been published. The present study deals with purification, characterization, and structural properties of a phosphodiesterase from Vipera lebetina venom (VLPDE). The VLPDE with molecular mass of about 120 kDa hydrolyses ADP but not ATP and 5'-AMP. The aggregation of platelets induced by ADP or collagen is dose-dependently inhibited by VLPDE. The cloning and sequencing of the VLPDE-encoding cDNA resulted in 2772-nt sequence with ORF of 2556 nt. The translated sequence comprises 851 amino acids including the 23-amino acid signal peptide. VLPDE is synthesized as a 828-amino acid single-chain protein but subsequently cleaved to form a two-chain protein held together with disulfide bonds. In reducing conditions the enzyme behaves like a heterodimeric protein but, differently from the real heterodimers, it is synthesized as a single-chain protein. VLPDE is the first snake venom phosphodiesterase with established and confirmed primary structure.
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Affiliation(s)
- Katrin Trummal
- National Institute of Chemical Physics and Biophysics, Tallinn, Estonia
| | - Anu Aaspõllu
- National Institute of Chemical Physics and Biophysics, Tallinn, Estonia
| | - Külli Tõnismägi
- National Institute of Chemical Physics and Biophysics, Tallinn, Estonia
| | - Mari Samel
- National Institute of Chemical Physics and Biophysics, Tallinn, Estonia
| | - Juhan Subbi
- National Institute of Chemical Physics and Biophysics, Tallinn, Estonia
| | - Jüri Siigur
- National Institute of Chemical Physics and Biophysics, Tallinn, Estonia
| | - Ene Siigur
- National Institute of Chemical Physics and Biophysics, Tallinn, Estonia.
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205
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Calvete JJ. Next-generation snake venomics: protein-locus resolution through venom proteome decomplexation. Expert Rev Proteomics 2014; 11:315-29. [PMID: 24678852 DOI: 10.1586/14789450.2014.900447] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Venom research has been continuously enhanced by technological advances. High-throughput technologies are changing the classical paradigm of hypothesis-driven research to technology-driven approaches. However, the thesis advocated in this paper is that full proteome coverage at locus-specific resolution requires integrating the best of both worlds into a protocol that includes decomplexation of the venom proteome prior to liquid chromatography-tandem mass spectrometry matching against a species-specific transcriptome. This approach offers the possibility of proof-checking the species-specific contig database using proteomics data. Immunoaffinity chromatography constitutes the basis of an antivenomics workflow designed to quantify the extent of cross-reactivity of antivenoms against homologous and heterologous venom toxins. In the author's view, snake venomics and antivenomics form part of a biology-driven conceptual framework to unveil the genesis and natural history of venoms, and their within- and between-species toxicological and immunological divergences and similarities. Understanding evolutionary trends across venoms represents the Rosetta Stone for generating broad-ranging polyspecific antivenoms.
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Affiliation(s)
- Juan J Calvete
- Instituto de Biomedicina de Valencia, Consejo Superior de Investigaciones Científicas, Jaime Roig 11, 46010 Valencia, Spain +34 963 391 778 +34 963 690 800
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206
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Sunagar K, Undheim EAB, Scheib H, Gren ECK, Cochran C, Person CE, Koludarov I, Kelln W, Hayes WK, King GF, Antunes A, Fry BG. Intraspecific venom variation in the medically significant Southern Pacific Rattlesnake (Crotalus oreganus helleri): biodiscovery, clinical and evolutionary implications. J Proteomics 2014; 99:68-83. [PMID: 24463169 DOI: 10.1016/j.jprot.2014.01.013] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Revised: 01/11/2014] [Accepted: 01/13/2014] [Indexed: 01/11/2023]
Abstract
UNLABELLED Due to the extreme variation of venom, which consequently results in drastically variable degrees of neutralization by CroFab antivenom, the management and treatment of envenoming by Crotalus oreganus helleri (the Southern Pacific Rattlesnake), one of the most medically significant snake species in all of North America, has been a clinician's nightmare. This snake has also been the subject of sensational news stories regarding supposed rapid (within the last few decades) evolution of its venom. This research demonstrates for the first time that variable evolutionary selection pressures sculpt the intraspecific molecular diversity of venom components in C. o. helleri. We show that myotoxic β-defensin peptides (aka: crotamines/small basic myotoxic peptides) are secreted in large amounts by all populations. However, the mature toxin-encoding nucleotide regions evolve under the constraints of negative selection, likely as a result of their non-specific mode of action which doesn't enforce them to follow the regime of the classic predator-prey chemical arms race. The hemorrhagic and tissue destroying snake venom metalloproteinases (SVMPs) were secreted in larger amounts by the Catalina Island and Phelan rattlesnake populations, in moderate amounts in the Loma Linda population and in only trace levels by the Idyllwild population. Only the Idyllwild population in the San Jacinto Mountains contained potent presynaptic neurotoxic phospholipase A2 complex characteristic of Mohave Rattlesnake (Crotalus scutulatus) and Neotropical Rattlesnake (Crotalus durissus terrificus). The derived heterodimeric lectin toxins characteristic of viper venoms, which exhibit a diversity of biological activities, including anticoagulation, agonism/antagonism of platelet activation, or procoagulation, appear to have evolved under extremely variable selection pressures. While most lectin α- and β-chains evolved rapidly under the influence of positive Darwinian selection, the β-chain lectin of the Catalina Island population appears to have evolved under the constraint of negative selection. Both lectin chains were conspicuously absent in both the proteomics and transcriptomics of the Idyllwild population. Thus, we not only highlight the tremendous biochemical diversity in C. o. helleri's venom-arsenal, but we also show that they experience remarkably variable strengths of evolutionary selection pressures, within each toxin class among populations and among toxin classes within each population. The mapping of geographical venom variation not only provides additional information regarding venom evolution, but also has direct medical implications by allowing prediction of the clinical effects of rattlesnake bites from different regions. Such information, however, also points to these highly variable venoms as being a rich source of novel toxins which may ultimately prove to be useful in drug design and development. BIOLOGICAL SIGNIFICANCE These results have direct implications for the treatment of envenomed patients. The variable venom profile of Crotalus oreganus helleri underscores the biodiscovery potential of novel snake venoms.
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Affiliation(s)
- Kartik Sunagar
- Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, 4169-007 Porto, Portugal; CIIMAR/CIMAR, Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Rua dos Bragas 289, P 4050-123 Porto, Portugal
| | - Eivind A B Undheim
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St. Lucia, Queensland, Australia; Institute for Molecular Bioscience, University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Holger Scheib
- Institute for Molecular Bioscience, University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Eric C K Gren
- Department of Earth and Biological Sciences, Loma Linda University, Loma Linda, CA 92350, USA
| | - Chip Cochran
- Department of Earth and Biological Sciences, Loma Linda University, Loma Linda, CA 92350, USA
| | - Carl E Person
- Department of Earth and Biological Sciences, Loma Linda University, Loma Linda, CA 92350, USA
| | - Ivan Koludarov
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St. Lucia, Queensland, Australia
| | - Wayne Kelln
- Department of Earth and Biological Sciences, Loma Linda University, Loma Linda, CA 92350, USA
| | - William K Hayes
- Department of Earth and Biological Sciences, Loma Linda University, Loma Linda, CA 92350, USA
| | - Glenn F King
- Institute for Molecular Bioscience, University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Agosthino Antunes
- Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, 4169-007 Porto, Portugal; CIIMAR/CIMAR, Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Rua dos Bragas 289, P 4050-123 Porto, Portugal
| | - Bryan Grieg Fry
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St. Lucia, Queensland, Australia; Institute for Molecular Bioscience, University of Queensland, St. Lucia, Queensland 4072, Australia.
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207
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Margres MJ, McGivern JJ, Wray KP, Seavy M, Calvin K, Rokyta DR. Linking the transcriptome and proteome to characterize the venom of the eastern diamondback rattlesnake (Crotalus adamanteus). J Proteomics 2014; 96:145-58. [DOI: 10.1016/j.jprot.2013.11.001] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Revised: 10/25/2013] [Accepted: 11/01/2013] [Indexed: 12/20/2022]
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208
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Snake venomics: From the inventory of toxins to biology. Toxicon 2013; 75:44-62. [DOI: 10.1016/j.toxicon.2013.03.020] [Citation(s) in RCA: 148] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Revised: 03/06/2013] [Accepted: 03/13/2013] [Indexed: 01/05/2023]
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209
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Aird SD, Watanabe Y, Villar-Briones A, Roy MC, Terada K, Mikheyev AS. Quantitative high-throughput profiling of snake venom gland transcriptomes and proteomes (Ovophis okinavensis and Protobothrops flavoviridis). BMC Genomics 2013; 14:790. [PMID: 24224955 PMCID: PMC3840601 DOI: 10.1186/1471-2164-14-790] [Citation(s) in RCA: 117] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2013] [Accepted: 10/26/2013] [Indexed: 01/20/2023] Open
Abstract
Background Advances in DNA sequencing and proteomics have facilitated quantitative comparisons of snake venom composition. Most studies have employed one approach or the other. Here, both Illumina cDNA sequencing and LC/MS were used to compare the transcriptomes and proteomes of two pit vipers, Protobothrops flavoviridis and Ovophis okinavensis, which differ greatly in their biology. Results Sequencing of venom gland cDNA produced 104,830 transcripts. The Protobothrops transcriptome contained transcripts for 103 venom-related proteins, while the Ovophis transcriptome contained 95. In both, transcript abundances spanned six orders of magnitude. Mass spectrometry identified peptides from 100% of transcripts that occurred at higher than contaminant (e.g. human keratin) levels, including a number of proteins never before sequenced from snakes. These transcriptomes reveal fundamentally different envenomation strategies. Adult Protobothrops venom promotes hemorrhage, hypotension, incoagulable blood, and prey digestion, consistent with mammalian predation. Ovophis venom composition is less readily interpreted, owing to insufficient pharmacological data for venom serine and metalloproteases, which comprise more than 97.3% of Ovophis transcripts, but only 38.0% of Protobothrops transcripts. Ovophis venom apparently represents a hybrid strategy optimized for frogs and small mammals. Conclusions This study illustrates the power of cDNA sequencing combined with MS profiling. The former quantifies transcript composition, allowing detection of novel proteins, but cannot indicate which proteins are actually secreted, as does MS. We show, for the first time, that transcript and peptide abundances are correlated. This means that MS can be used for quantitative, non-invasive venom profiling, which will be beneficial for studies of endangered species.
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Affiliation(s)
- Steven D Aird
- Okinawa Institute of Science and Technology, Tancha 1919-1, Onna-son, Kunigami-gun, Okinawa-ken 904-0412, Japan.
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210
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Atractaspis aterrima toxins: the first insight into the molecular evolution of venom in side-stabbers. Toxins (Basel) 2013; 5:1948-64. [PMID: 24169588 PMCID: PMC3847709 DOI: 10.3390/toxins5111948] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Revised: 10/19/2013] [Accepted: 10/22/2013] [Indexed: 12/13/2022] Open
Abstract
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.
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211
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von Reumont BM, Blanke A, Richter S, Alvarez F, Bleidorn C, Jenner RA. The first venomous crustacean revealed by transcriptomics and functional morphology: remipede venom glands express a unique toxin cocktail dominated by enzymes and a neurotoxin. Mol Biol Evol 2013; 31:48-58. [PMID: 24132120 PMCID: PMC3879455 DOI: 10.1093/molbev/mst199] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Animal venoms have evolved many times. Venomous species are especially common in three of the four main groups of arthropods (Chelicerata, Myriapoda, and Hexapoda), which together represent tens of thousands of species of venomous spiders, scorpions, centipedes, and hymenopterans. Surprisingly, despite their great diversity of body plans, there is no unambiguous evidence that any crustacean is venomous. We provide the first conclusive evidence that the aquatic, blind, and cave-dwelling remipede crustaceans are venomous and that venoms evolved in all four major arthropod groups. We produced a three-dimensional reconstruction of the venom delivery apparatus of the remipede Speleonectes tulumensis, showing that remipedes can inject venom in a controlled manner. A transcriptomic profile of its venom glands shows that they express a unique cocktail of transcripts coding for known venom toxins, including a diversity of enzymes and a probable paralytic neurotoxin very similar to one described from spider venom. We screened a transcriptomic library obtained from whole animals and identified a nontoxin paralog of the remipede neurotoxin that is not expressed in the venom glands. This allowed us to reconstruct its probable evolutionary origin and underlines the importance of incorporating data derived from nonvenom gland tissue to elucidate the evolution of candidate venom proteins. This first glimpse into the venom of a crustacean and primitively aquatic arthropod reveals conspicuous differences from the venoms of other predatory arthropods such as centipedes, scorpions, and spiders and contributes valuable information for ultimately disentangling the many factors shaping the biology and evolution of venoms and venomous species.
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Affiliation(s)
- Björn M von Reumont
- Department of Life Sciences, The Natural History Museum, London, United Kingdom
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212
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Margres MJ, Aronow K, Loyacano J, Rokyta DR. The venom-gland transcriptome of the eastern coral snake (Micrurus fulvius) reveals high venom complexity in the intragenomic evolution of venoms. BMC Genomics 2013; 14:531. [PMID: 23915248 PMCID: PMC3750283 DOI: 10.1186/1471-2164-14-531] [Citation(s) in RCA: 102] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Accepted: 07/29/2013] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND 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. RESULTS 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. CONCLUSIONS 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 significantly higher than that of nontoxins. Diversification among toxins appeared to follow speciation reflecting species-specific adaptation, and this divergence may be directly related to dietary shifts and is suggestive of a coevolutionary arms race.
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Affiliation(s)
- Mark J Margres
- Department of Biological Science, Florida State University, Tallahassee, FL 32306-4295, USA
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213
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Warrell DA, Gutiérrez JM, Calvete JJ, Williams D. New approaches & technologies of venomics to meet the challenge of human envenoming by snakebites in India. Indian J Med Res 2013; 138:38-59. [PMID: 24056555 PMCID: PMC3767246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
The direct estimate of 46,000 snakebite deaths in India in 2005 (1 for every 2 HIV/AIDS deaths), based on verbal autopsies, renders unrealistic the total of only 47,000 snakebite deaths in the whole world in 2010, obtained indirectly as part of the "Global Burden of Disease 2010" study. Persistent underestimation of its true morbidity and mortality has made snakebite the most neglected of all the WHO's "neglected tropical diseases", downgrading its public health importance. Strategies to address this neglect should include the improvement of antivenom, the only specific antidote to envenoming. To accommodate increased understanding of geographical intraspecific variation in venom composition and the range of snake species that are medically important in India, the design of antivenoms (choice of venom sources and species coverage) should be reconsidered. Methods of preclinical and clinical testing should be improved. The relatively new science of venomics involves techniques and strategies for assessing the toxin composition of snake venoms directly through proteomics-centred approaches or indirectly via high-throughput venom gland transcriptomics and bioinformatic analysis. Antivenomics is translational venomics: a proteomics-based protocol to quantify the extent of cross-reactivity of antivenoms against homologous and heterologous venoms. These approaches could revolutionize the preclinical assessment of antivenom efficacy, leading to a new generation of antivenoms that are clinically more effective.
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Affiliation(s)
- David A. Warrell
- Global Snakebite Initiative, P.O. Box 193, Herston, Qld, 4029, Australia,Nuffield Department of Clinical Medicine, University of Oxford, John Radcliffe Hospital, Headington, Oxford, OX3 9DU, UK,Reprint requests: Prof. David A. Warrell, Nuffield Department of Clinical Medicine, University of Oxford, John Radcliffe Hospital, Headington, Oxford, OX3 9DU, UK e-mail:
| | - José María Gutiérrez
- Global Snakebite Initiative, P.O. Box 193, Herston, Qld, 4029, Australia,Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica
| | - Juan J. Calvete
- Global Snakebite Initiative, P.O. Box 193, Herston, Qld, 4029, Australia,Laboratorio de Venómica y Proteinómíca Estructural, Instituto de Biomedicina de Valencia, CSIC, Jaime Roig 11, 46010 Valencia, Spain
| | - David Williams
- Global Snakebite Initiative, P.O. Box 193, Herston, Qld, 4029, Australia,Australian Venom Research Unit, Department of Pharmacology, University of Melbourne, Parkville, Vic, 3010. Australia,School of Medicine & Health Sciences, University of Papua New Guinea, Boroko, NCD, Papua New Guinea
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214
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The genesis of an exceptionally lethal venom in the timber rattlesnake (Crotalus horridus) revealed through comparative venom-gland transcriptomics. BMC Genomics 2013; 14:394. [PMID: 23758969 PMCID: PMC3701607 DOI: 10.1186/1471-2164-14-394] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Accepted: 05/30/2013] [Indexed: 01/09/2023] Open
Abstract
Background Snake venoms generally show sequence and quantitative variation within and between species, but some rattlesnakes have undergone exceptionally rapid, dramatic shifts in the composition, lethality, and pharmacological effects of their venoms. Such shifts have occurred within species, most notably in Mojave (Crotalus scutulatus), South American (C. durissus), and timber (C. horridus) rattlesnakes, resulting in some populations with extremely potent, neurotoxic venoms without the hemorrhagic effects typical of rattlesnake bites. Results To better understand the evolutionary changes that resulted in the potent venom of a population of C. horridus from northern Florida, we sequenced the venom-gland transcriptome of an animal from this population for comparison with the previously described transcriptome of the eastern diamondback rattlesnake (C. adamanteus), a congener with a more typical rattlesnake venom. Relative to the toxin transcription of C. adamanteus, which consisted primarily of snake-venom metalloproteinases, C-type lectins, snake-venom serine proteinases, and myotoxin-A, the toxin transcription of C. horridus was far simpler in composition and consisted almost entirely of snake-venom serine proteinases, phospholipases A2, and bradykinin-potentiating and C-type natriuretic peptides. Crotalus horridus lacked significant expression of the hemorrhagic snake-venom metalloproteinases and C-type lectins. Evolution of shared toxin families involved differential expansion and loss of toxin clades within each species and pronounced differences in the highly expressed toxin paralogs. Toxin genes showed significantly higher rates of nonsynonymous substitution than nontoxin genes. The expression patterns of nontoxin genes were conserved between species, despite the vast differences in toxin expression. Conclusions Our results represent the first complete, sequence-based comparison between the venoms of closely related snake species and reveal in unprecedented detail the rapid evolution of snake venoms. We found that the difference in venom properties resulted from major changes in expression levels of toxin gene families, differential gene-family expansion and loss, changes in which paralogs within gene families were expressed at high levels, and higher nonsynonymous substitution rates in the toxin genes relative to nontoxins. These massive alterations in the genetics of the venom phenotype emphasize the evolutionary lability and flexibility of this ecologically critical trait.
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