Bothrops moojeni\'s snake venom and plasma anti-venom mechanisms: a biochemical and biological characterization.

Foi observado no Laboratório de Herpetologia do Instituto Butantan que indivíduos da espécie Bothrops moojeni, quando acidentados entre si, apresentavam casos de mortalidade ocasionados por efeitos do envenenamento. Um modelo composto de análises bioquímicas e biológicas de 13 amostras de veneno e plasma de serpentes B. moojeni foi utilizado. SDS-PAGE mostrou perfis proteicos bem distintos para as amostras de veneno, e não para as de plasma. Western Blottings (WB) com amostras desses plasmas mostraram uma zona de detecção na faixa de 25 kDa em alguns indivíduos. Outro teste de WB, cruzando amostras de plasmas e venenos, mostrou que alguns indivíduos possuem proteínas que se ligam à estas regiões do plasma, o que não ocorre com o veneno dos outros indivíduos testados. Espectrometria de massas mostrou que esses indivíduos apresentam maiores concentrações proteicas e outras tantas exclusivas, incluindo inibidores de fosfolipases. A Dose Letal 50% mostrou uma maior eficiência nesses venenos, enquanto que a Dose Mínima Hemorrágica se mostrou inferior. Conclui-se que alguns indivíduos dessa espécie apresentam diferenças na composição dos seus venenos que se tornam significativas para o envenenamento.It was observed in the Herpetology Laboratory of the Butantan Institute that individuals of the species Bothrops moojeni, when injured among themselves, presented cases of mortality caused by the effects of envenoming. A model composed of biochemical and biological analyzes of 13 venom and plasma samples of B. moojeni snakes was used. SDS-PAGE showed very different protein profiles for the venom samples, and not for the plasma ones. Western Blottings (WB) with samples of these plasmas showed a detection zone in the range of 25 kDa in some individuals. Another WB test, cross-linking plasma and venom samples, showed that some individuals have proteins that bind to these regions of the plasma, which does not occur with the venom of the other individuals tested. Mass spectrometry results showed that these individuals have higher protein and other unique concentrations, including phospholipase inhibitors. The Lethal Dose 50% showed a higher efficiency in these venoms, whereas the Minimum Hemorrhagic Dose was inferior. It is concluded that some individuals of this species present differences in the composition of their poisons that become significant for the envenoming process

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

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 analyses performed on two individuals revealed that these individuals present, in addition to higher protein concentrations, other exclusive proteins in their composition. When these same two 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 analyses in studies involving intraspecific venom variability and venom evolution