Venom complexity of Bothrops atrox (common lancehead) siblings

Variability in snake venoms is a well-studied phenomenon. However, sex-based variation of Bothrops atrox snake venom using siblings is poorly investigated. Bothrops atrox is responsible for the majority of snakebite accidents in the Brazilian Amazon region. Differences in the venom composition of Bothrops genus have been linked to several factors such as ontogeny, geographical distribution, prey preferences and sex. Thus, in the current study, venom samples of Bothrops atrox male and female siblings were analyzed in order to compare their biochemical and biological characteristics. Methods: Venoms were collected from five females and four males born from a snake captured from the wild in São Bento (Maranhão, Brazil), and kept in the Laboratory of Herpetology of Butantan Intitute. The venoms were analyzed individually and as a pool of each gender. The assays consisted in protein quantification, 1-DE, mass spectrometry, proteolytic, phospholipase A2, L-amino acid oxidase activities, minimum coagulant dose upon plasma, minimum hemorrhagic dose and lethal dose 50%. Results: Electrophoretic profiles of male's and female's venom pools were quite similar, with minor sex-based variation. Male venom showed higher LAAO, PLA2 and hemorrhagic activities, while female venom showed higher coagulant activity. On the other hand, the proteolytic activities did not show statistical differences between pools, although some individual variations were observed. Meanwhile, proteomic profile revealed 112 different protein compounds; of which 105 were common proteins of female's and male's venom pools and seven were unique to females. Despite individual variations, lethality of both pools showed similar values. Conclusion: Although differences between female and male venoms were observed, our results show that individual variations are significant even between siblings, highlighting that biological activities of venoms and its composition are influenced by other factors beyond gender.(AU)

Geographic variation of individual venom profile of Crotalus durissus snakes

South American rattlesnakes are represented in Brazil by a single species, Crotalus durissus, which has public health importance due to the severity of its envenomation and to its wide geographical distribution. The species is subdivided into several subspecies, but the current classification is controversial. In Brazil, the venoms of C. d. terrificus and C. d. collilineatus are used for hyperimmunization of horses for antivenom production, even though the distinction of these two subspecies are mostly by their geographical distribution. In this context, we described a comparative compositional and functional characterization of individual C. d. collilineatus and C. d. terrificus venoms from three Brazilian states. Methods: We compared the compositional patterns of C. d. terrificus and C. d. collilineatus individual venoms by 1-DE and RP-HPLC. For functional analyzes, the enzymatic activities of PLA2, LAAO, and coagulant activity were evaluated. Finally, the immunorecognition of venom toxins by the crotalic antivenom produced at Butantan Institute was evaluated using Western blotting. Results: The protein profile of individual venoms from C. d. collilineatus and C. d. terrificus showed a comparable overall composition, despite some intraspecific variation, especially regarding crotamine and LAAO. Interestingly, HPLC analysis showed a geographic pattern concerning PLA2. In addition, a remarkable intraspecific variation was also observed in PLA2, LAAO and coagulant activities. The immunorecognition pattern of individual venoms from C. d. collilineatus and C. d. terrificus by crotalic antivenom produced at Butantan Institute was similar. Conclusions: The results highlighted the individual variability among the venoms of C. durissus ssp. specimens. Importantly, our data point to a geographical variation of C. durissus ssp. venom profile, regardless of the subspecies, as evidenced by PLA2 isoforms complexity, which may explain the increase in venom neurotoxicity from Northeastern through Southern Brazil reported for the species.(AU)