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Comparative proteomics and biochemical analysis of venom of thirteen Bothrops moojeni specimens reveal several individual variations

ABSTRACT: Snake venoms are complex protein mixtures with different biological activities that can act in both their preys and human victims. Many of these proteins play a role in prey capture and in the digestive process of these animals. It is known that some snakes are resistant to the toxicity of their own venom by mechanisms not yet fully elucidated. However, it was observed in the Laboratory of Herpetology of Instituto Butantan that some Bothrops moojeni individuals injured by the same snake species showed mortalities caused by envenoming effects. This study analyzed the biochemical composition of 13 venom and plasma samples from Bothrops moojeni specimens to assess differences in their protein composition. Application of sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) showed distinct venom protein profiles, but very homogeneous plasma profiles. Western Blotting (WB) was performed with plasma samples, which were submitted to incubation with the respective venom. Some individuals showed an immunorecognized band zone around 25 kDa, indicating interaction between the same individual plasma and venom proteins. Crossed-WB assay using non-self-plasma and venom showed that this variability is due to venom protein composition instead of plasma composition. These venoms presented higher caseinolytic, collagenolytic and coagulant activities than the venoms without these regions recognized by WB. Mass spectrometry analysis revealed that these individuals present, in addition to higher protein concentrations, other exclusive proteins in their composition. When these samples were tested in vivo, the results also showed higher lethality in these venoms, but lower hemorrhagic activity than in the venoms without these regions recognized by WB. In conclusion, some Bothrops moojeni specimens differ in venom composition, which may have implications in envenomation. Moreover, the high individual venom variability found in this species demonstrates the importance to work with individual analysis in studies involving intraspecific venom variability and venom evolution.

INSTRUMENT(S): Synapt MS

ORGANISM(S): Bothrops Moojeni

TISSUE(S): Venom

SUBMITTER: Alexandre Keiji Tashima

LAB HEAD: Alexandre Keiji Tashima

PROVIDER: PXD012585 | Pride | 2019-09-26

REPOSITORIES: Pride

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Comparative compositional and functional analyses of Bothrops moojeni specimens reveal several individual variations.

Aguiar Weslei da Silva WDS Galizio Nathália da Costa NDC Serino-Silva Caroline C Sant'Anna Sávio Stefanini SS Grego Kathleen Fernandes KF Tashima Alexandre Keiji AK Nishiduka Erika Sayuri ES Morais-Zani Karen de K Tanaka-Azevedo Anita Mitico AM

PloS one 20190912 9

Snake venoms are complex protein mixtures with different biological activities that can act in both their preys and human victims. Many of these proteins play a role in prey capture and in the digestive process of these animals. It is known that some snakes are resistant to the toxicity of their own venom by mechanisms not yet fully elucidated. However, it was observed in the Laboratory of Herpetology of Instituto Butantan that some Bothrops moojeni individuals injured by the same snake species ...[more]

PMID: 31513632

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Project description:Bothrops moojeni has a wide distribution in Brazil and represents a serious medical concern at some localities. Previous works reported that the manifestations of snakebites caused by B. moojeni juveniles were mainly related to coagulation, while those caused by adults had more prominent local damage. In this work, we aimed to analyze the venoms of B. moojeni at different life stages to better understand how the venom shifts along the ontogeny. Snakes were grouped by age and sex, and venom pools were formed accordingly. Compositional analyses by one-dimensional electrophoresis (1-DE), chromatography and mass spectrometry revealed that ontogenetic changes may be mostly related to phospholipase A2 (PLA2) and metalloproteases. Regarding the functional aspect of the venoms, in vitro assays of proteolytic, L-amino acid oxidase, PLA2 and coagulant activities were assayed, but only the first and the last showed age-related changes, with the venom of younger snakes displaying lower proteolytic and higher coagulant activities up to 1 year-old; from 2 years-old onward, the venoms presented the opposite relation. The venoms of 3 years-old snakes were exceptions to the compositional and functional pattern of adults. Sex-related differences were observed at specific groups and not related to age. In vivo experiments (median lethal dose and hemorrhagic activity) were statistically similar between neonates and adults, but observation of the time each venom took to kill the mice revealed that the adult one seemed to act faster than the venoms of the neonates. All venoms were mostly recognized by the antibothropic serum and displayed similar profiles to 1-DE in western blotting. In conclusion, the venoms showed ontogenetic shift in composition and activities. Furthermore, this change occurred from 1 to 2 years-old, and interestingly the 3 years-old pools had particular characteristics, which highlight the importance of extending the studies to better understand venom variability.

Project description:Elucidating the molecular mechanisms underlying snake venom variability provides important clues for understanding how the biological functions of this powerful toxic arsenal evolve. We analyzed in detail individual transcripts and venom protein isoforms produced by five specimens of a venomous snake (Bothrops atrox) from two nearby but genetically distinct populations from the Brazilian Amazon rainforest which show functional similarities in venom properties. Individual variation was observed among the venoms of these specimens, but the overall abundance of each general toxin family was conserved both in transcript and in venom protein levels. However, when expression of independent paralogues was analyzed, remarkable differences were observed within and among each toxin group, both between individuals and between populations. Transcripts for functionally essential venom proteins (“core function” proteins) were highly expressed in all specimens and showed similar transcription/translation rates. In contrast, other paralogues (“adaptive” proteins) showed lower expression levels and the toxins they coded for varied among different individuals. These results provide support for the inferences that (a) expression and translational differences play a greater role in defining adaptive variation in venom phenotypes than does sequence variation in protein coding genes and (b) convergent adaptive venom phenotypes can be generated through different molecular mechanisms. Significance: Analysis of individual transcripts and venom protein isoforms produced by specimens of a venomous snake (Bothrops atrox), from the Brazilian Amazon rainforest, revealed that transcriptional and translational mechanisms contribute to venom phenotypic variation. Our finding of evidence for high expression of toxin proteins with conserved function supports the hypothesis that the venom phenotype consists of two kinds of proteins: conserved “core function” proteins that provide essential functional activities with broader relevance and less conserved “adaptive” proteins that vary in expression and may permit customization of protein function. These observations allowed us to suggest that genetic mechanisms controlling venom variability are not restricted to selection of gene copies or mutations in structural genes but also to selection of the mechanisms controlling gene expression, contributing to the plasticity of this important phenotype for venomous snakes.

Project description:Assassin bugs (Hemiptera: Heteroptera: Reduviidae) are venomous insects that prey on invertebrates. Assassin bug venom has features in common with venoms from other animals, such as paralysing and lethal activity when injected, and a molecular composition that includes disulfide-rich peptide neurotoxins. Uniquely, this venom also has strong liquefying activity that has been hypothesised to facilitate feeding through the narrow channel of the proboscis—a structure inherited from sap- and phloem-feeding phytophagous hemipterans and adapted during the evolution of Heteroptera into a fang and feeding structure. However, further understanding of the function of assassin bug venom is impeded by the lack of proteomic studies detailing its molecular composition. In addition, the lack of knowledge regarding venoms of predaceous reduviids limits our understanding of how the venoms of the blood-feeding kissing bugs (Reduviidae: Triatominae) evolved to facilitate hematophagy. By using a combined transcriptomic/proteomic approach we show that the venom proteome of the harpactorine assassin bug Pristhesancus plagipennis includes a complex suite of >100 proteins comprising disulfide-rich peptides, CUB-domain proteins, cystatins, putative cytolytic toxins, triabin-like protein, odorant binding protein, serine proteases, catabolic enzymes, putative nutrient-binding proteins, plus eight families of proteins without homology to characterised proteins. Serine proteases, CUB domain proteins and other novel proteins in the 10–16 kDa mass range, as well as putative cytolytic toxins, were the most abundant venom components. Thus, in addition to putative neurotoxins, assassin bug venom includes a high proportion of enzymatic and cytolytic venom components well suited to tissue liquefaction. While some protein families such as lipocalin/triabins occur in the venoms of both predaceous and blood-feeding reduviids, the composition of venoms in these two groups differs markedly. These results provide insights into the venom evolution in the insect suborder Heteroptera.

Dataset Information

Comparative proteomics and biochemical analysis of venom of thirteen Bothrops moojeni specimens reveal several individual variations

Publications

Comparative compositional and functional analyses of Bothrops moojeni specimens reveal several individual variations.

Similar Datasets

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