Análise da variação sexual e ontogenética de venenos da espécie Bothrops alternatus Duméril, Bibron & Duméril, 1854. (Serpentes, Viperidae)

Abstract

Snakes are complex mixtures whose main functions are the stoppage and the killing of prey as well as the initial promotion of digestion and their actions may vary according to the age, geographical distribution and individual character of each snake. The venom of Bothrops alternatus, as well as most of the botrópico venoms, has as main actions, proteolytic, coagulant and hemorrhagic activities. The objective of this study was to evaluate the possible variations of venoms of male and female snakes of the Bothrops alternatus species throughout the development, through biochemical characterization (protein dosage, SDS-PAGE electrophoresis, gelatinolytic activity, caseinolytic activity and coagulant activity) and biological characterization (hemorrhagic and myotoxic activity). As a result, protein content of male and female venoms did not show ontogenetic or sexual variation, with 90 to 100% protein content. The electrophoretic profiles of the venoms were similar, but a protein with an approximate molecular weight of 17.0 kDa varied between the sexes and as the snakes developed. By means of the SDS-PAGE zimography and caseinolytic activity, it was possible to observe that the proteolytic action of the female venoms was not very active, with action only in the third and fourth year, whereas the male venoms showed activity only in the first year of life. The B. alternatus venoms had the ability to coagulate citrated equine plasma in 60 seconds and venoms of both sexes were more coagulant in the first year of life, suffering a decline in action throughout development. In the hemorrhagic activity the venom samples presented sexual variation, and the ontogenetic variation was only observed in the venoms of males, where they were more active in the fourth year of age. The myotoxic activity of B. alternatus venoms showed that there is sexual variation, whereas ontogenetic variation was only identified in the venom of males, with oscillations of the specific activity values for the CK enzyme. By means of the joint analysis of the data generated, we conclude that there is sexual and ontogenetic variation in venoms of the species B. alternatus and that several factors can influence in the triggering of their actions and activities, since environmental and genetic factors are the key to the maintenance species in the habitat in which they live.