Interspecific and intraspecific variation in venom proteomics, composition, and antivenom efficacy of Thai cobras (Naja spp.): Highlighting the distinct profile of the newly identified Naja fuxi.

BackgroundThe king cobra (Ophiophagus hannah) is widely distributed throughout many parts of Asia. This study aims to investigate the complexity of Malaysian Ophiophagus hannah (MOh) venom for a better understanding of king cobra venom variation and its envenoming pathophysiology. The venom gland transcriptome was investigated using the Illumina HiSeq™ platform, while the venom proteome was profiled by 1D-SDS-PAGE-nano-ESI-LCMS/MS.ResultsTranscriptomic results reveal high redundancy of toxin transcripts (3357.36 FPKM/transcript) despite small cluster numbers, implying gene duplication and diversification within restricted protein families. Among the 23 toxin families identified, three-finger toxins (3FTxs) and snake-venom metalloproteases (SVMPs) have the most diverse isoforms. These 2 toxin families are also the most abundantly transcribed, followed in descending order by phospholipases A2 (PLA2s), cysteine-rich secretory proteins (CRISPs), Kunitz-type inhibitors (KUNs), and L-amino acid oxidases (LAAOs). Seventeen toxin families exhibited low mRNA expression, including hyaluronidase, DPP-IV and 5’-nucleotidase that were not previously reported in the venom-gland transcriptome of a Balinese O. hannah. On the other hand, the MOh proteome includes 3FTxs, the most abundantly expressed proteins in the venom (43 % toxin sbundance). Within this toxin family, there are 6 long-chain, 5 short-chain and 2 non-conventional 3FTx. Neurotoxins comprise the major 3FTxs in the MOh venom, consistent with rapid neuromuscular paralysis reported in systemic envenoming. The presence of toxic enzymes such as LAAOs, SVMPs and PLA2 would explain tissue inflammation and necrotising destruction in local envenoming. Dissimilarities in the subtypes and sequences between the neurotoxins of MOh and Naja kaouthia (monocled cobra) are in agreement with the poor cross-neutralization activity of N. kaouthia antivenom used against MOh venom. Besides, the presence of cobra venom factor, nerve growth factors, phosphodiesterase, 5’-nucleotidase, and DPP-IV in the venom proteome suggests its probable hypotensive action in subduing prey.ConclusionThis study reports the diversity and abundance of toxins in the venom of the Malaysian king cobra (MOh). The results correlate with the pathophysiological actions of MOh venom, and dispute the use of Naja cobra antivenoms to treat MOh envenomation. The findings also provide a deeper insight into venom variations due to geography, which is crucial for the development of a useful pan-regional antivenom.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-015-1828-2) contains supplementary material, which is available to authorized users.

Combined venomics, antivenomics and venom gland transcriptome analysis of the monocoled cobra (Naja kaouthia) from China

The spectacled cobra (Naja naja) and monocled cobra (Naja kaouthia), widespread venomous snakes in South and Southeast Asia, occur in diverse habitats and cause neurotoxic envenoming. Despite reported venom variability of these two cobras across their range, no comparative study has been conducted from the interconnected but distinct habitats of Bangladesh. Using venomics and antivenomics, we analysed 26 individual venom samples of N. kaouthia and 17 of N. naja from Bangladesh across age groups and locations, respectively. Significant interspecific and intraspecific venom variability was observed, with geographically connected populations showing minimal divergence, while isolated populations (separated by river barriers or distinct ecosystems) exhibited pronounced compositional differences. Ontogenetic differences in venom composition between adult N. kaouthia and their juvenile offspring were detected. Commercially available Incepta polyvalent antivenom, produced against India's "Big Four" (including southern Indian N. naja), demonstrated poor efficacy against Bangladeshi cobra venoms. Collectively, our analyses demonstrate the existence of multi-dimensional variation in cobra venoms of Bangladesh that is influenced by biotic and abiotic factors. We emphasize the urgent need for region-specific antivenoms incorporating venom from ecologically distinct populations and age groups of both species across South Asia to improve snakebite treatment efficacy as well pre-clinical assessments to address biogeographic and ontogenetic venom diversity. SIGNIFICANCE: Snakebite envenoming is a major neglected tropical disease and a leading occupational health hazard especially for rural populations in many low-and middle-income countries. As differences in snake venom composition between and within species can greatly affect the clinical course of envenoming and the efficacy of treatment, detailed knowledge of this variability is highly important for public health planning and the development of better antidotes. In Bangladesh, the monocled cobra (Naja kaouthia) and the spectacled cobra (Naja naja) belong to the medically most important and most widely distributed common snake species, but data on the variability of their venoms in this country has been limited and its relation to climatic and other environmental factors remained unexplored. Here we report on the analysis of 43 individual venom samples from 26N. kaouthia and 17N. naja from different age groups and geographical localities in Bangladesh, using venomics and antivenomics methods. Our findings show that the venoms of these cobras are highly diverse qualitatively and quantitatively, with significant inter- and intraspecific, geographic and ontogenetic variability and differences in their reactivity with a commercial antivenom. The observed geographical variability appears to be influenced by climatic and other environmental variables of different habitats in Bangladesh. When designing improved antivenoms, geographically appropriate and more diverse venom samples, also from different age groups of the snakes, should be included to cover this variability and ensure that the clinically significant toxins of all cobra venom varieties in Bangladesh are well neutralized by the antivenoms.

Thamnophis sirtalis and their toxic relationship: Testing for intraspecific venom variation in Common Garter Snakes

Cosine similarity analysis of venom proteomes of Indian cobras, Naja naja and Naja kaouthia reveals significant interspecies and geographic variations.

The toxin composition of snake venoms and, thus, their functional activity, can vary between and within species. Intraspecific venom variation across a species’ geographic range is a major concern for antivenom treatment of envenomations, particularly for countries like French Guiana that lack a locally produced antivenom. Bothrops asper and Bothrops atrox are the most medically significant species of snakes in Latin America, both producing a variety of clinical manifestations, including systemic bleeding. These pathophysiological actions are due to the activation by the venom of the blood clotting factors Factor X and prothrombin, thereby causing severe consumptive coagulopathy. Both species are extremely wide-ranging, and previous studies have shown their venoms to exhibit regional venom variation. In this study, we investigate the differential coagulotoxic effects on human plasma of six venoms (four B. asper and two B. atrox samples) from different geographic locations, spanning from Mexico to Peru. We assessed how the venom variation of these venom samples affects neutralisation by five regionally available antivenoms: Antivipmyn, Antivipmyn-Tri, PoliVal-ICP, Bothrofav, and Soro Antibotrópico (SAB). The results revealed both inter- and intraspecific variations in the clotting activity of the venoms. These variations in turn resulted in significant variation in antivenom efficacy against the coagulotoxic effects of these venoms. Due to variations in the venoms used in the antivenom production process, antivenoms differed in their species-specific or geographical neutralisation capacity. Some antivenoms (PoliVal-ICP, Bothrofav, and SAB) showed species-specific patterns of neutralisation, while another antivenom (Antivipmyn) showed geographic-specific patterns of neutralisation. This study adds to current knowledge of Bothrops venoms and also illustrates the importance of considering evolutionary biology when developing antivenoms. Therefore, these results have tangible, real-world implications by aiding evidence-based design of antivenoms for treatment of the envenomed patient. We stress that these in vitro studies must be backed by future in vivo studies and clinical trials before therapeutic guidelines are issued regarding specific antivenom use in a clinical setting.

King Cobra (Ophiophagus hannah) has a significant place in manycultures, and is a medically important venomous snake in the world. Envenomationby this snake is highly lethal, manifested mainly by neurotoxicity and localtissue damage. King Cobra may be part of a larger species complex, and is widelydistributed across Southeast Asia, southern China, northern and eastern regionsas well as the Western Ghats of India, indicating potential geographicalvariation in venom composition. There is, however, only one species-specificKing Cobra antivenom available worldwide that is produced in Thailand, usingvenom from the snake of Thai origin. Issues relating to the management of KingCobra envenomation (e.g., variation in the composition andtoxicity of the venom, limited availability and efficacy of antivenom), andchallenges faced in the research of venom (in particular proteomics), are rarelyaddressed. This article reviews the natural history and sociocultural importanceof King Cobra, cases of snakebite envenomation caused by this species, currentpractice of management (preclinical and clinical), and major toxinologicalstudies of the venom with a focus on venom proteomics, toxicity andneutralization. Unfortunately, epidemiological data of King Cobra bite isscarce, and venom proteomes reported in various studies revealed markeddiscrepancies in details. Challenges, such as inconsistency in snake venomsampling, varying methodology of proteomic analysis, lack of mechanistic andantivenomic studies, and controversy surrounding antivenom use in treating KingCobra envenomation are herein discussed. Future directions are proposed,including the effort to establish a standard, comprehensive Pan-Asian proteomicdatabase of King Cobra venom, from which the venom variation can be determined.Research should be undertaken to characterize the toxin antigenicity, and todevelop an antivenom with improved efficacy and wider geographical utility. Theendeavors are aligned with the WHO´s roadmap that aims to reduce the diseaseburden of snakebite by 50% before 2030.

Proteomic and biochemical analyses of short-tailed pit viper (Gloydius brevicaudus) venom: Age-related variation and composition–activity correlation

P1E115 - Gabaergic-benzodiazepine system is involved in the crotoxin-induced behavioral alterations

The venom and transcriptome profile of the captive Chinese cobra (Naja atra) is not characterized until now. Here, LC-MS/MS and illumine technology were used to unveil the venom and trascriptome of neonates and adults N. atra specimens. In captive Chinese cobra, 98 co-existing transcripts for venom-related proteins was contained. A total of 127 proteins belong to 21 protein families were found in the profile of venom. The main components of snake venom were three finger toxins (3-FTx), snake venom metalloproteinase (SVMP), cysteine-rich secretory protein (CRISP), cobra venom factor (CVF), and phosphodiesterase (PDE). During the ontogenesis of captive Chinese cobra, the rearrangement of snake venom composition occurred and with obscure gender difference. CVF, 3-FTx, PDE, phospholipase A2 (PLA2) in adults were more abundant than neonates, while SVMP and CRISP in the neonates was richer than the adults. Ontogenetic changes in the proteome of Chinese cobra venom reveals different strategies for handling prey. The levels of different types of toxin families were dramatically altered in the wild and captive specimens. Therefore, we speculate that the captive process could reshape the snake venom composition vigorously. The clear comprehension of the composition of Chinese cobra venom facilitates the understanding of the mechanism of snakebite intoxication and guides the preparation and administration of traditional antivenom and next-generation drugs for snakebite.

Proteomics, functional characterization and antivenom neutralization of the venom of Pakistani Russell's viper (Daboia russelii) from the wild

Venom variation among the three subspecies of the North African mountain viper Vipera monticola Saint Girons 1953

Proteomic analysis of Moroccan cobra Naja haje legionis venom using tandem mass spectrometry

Isolement, purification et étude d'une phospholipase A 2 toxique du venin de Vipera berus

The isolation and characterization of individual snake venom components is important for a deeper understanding of the pathophysiology of envenomation and for improving the therapeutic procedures of patients. It also opens possibilities for the discovery of novel toxins that might be useful as tools for understanding cellular and molecular processes. The variable venom composition, toxicological and immunological properties of the common vipers (Vipera berus berus) have been reviewed. The combination of venom gland transcriptomics, bottom-up and top-down proteomics enabled comparison of common viper venom proteomes from multiple individuals. V. b. berus venom contains proteins and peptides belonging to 10–15 toxin families: snake venom metalloproteinase, phospholipases A2 (PLA2), snake venom serine proteinase, aspartic protease, L-amino acid oxidase (LAAO), hyaluronidase, 5′-nucleotidase, glutaminyl-peptide cyclotransferase, disintegrin, C-type lectin (snaclec), nerve growth factor, Kunitz type serine protease inhibitor, snake venom vascular endothelial growth factor, cysteine-rich secretory protein, bradykinin potentiating peptide, natriuretic peptides. PLA2 and LAAO from V. b. berus venom produce more pronounced cytotoxic effects in cancer cells than normal cells, via induction of apoptosis, cell cycle arrest and suppression of proliferation. Proteomic data of V. b. berus venoms from different parts of Russia and Slovakian Republic have been compared with analogous data for Vipera nikolskii venom. Proteomic studies demonstrated quantitative differences in the composition of V. b. berus venom from different geographical regions. Differences in the venom composition of V. berus were mainly driven by the age, sex, habitat and diet of the snakes. The venom variability of V. berus results in a loss of antivenom efficacy against snakebites. The effectiveness of antibodies is discussed. This review presents an overview with a special focus on different toxins that have been isolated and characterized from the venoms of V. b. berus. Their main biochemical properties and toxic actions are described.