Caracterização de adaptações do repertório molecular de serpentes das tribos Xenodontini e Pseudoboini relacionadas à sua ecologia de predação

Abstract

Among the wide spectrum of food ecologies, some groups of snakes have become ophiophagous, feeding mainly on other snakes. Due to the relationship between diet and venom composition, these ophiophagous groups probably needed to develop specific toxins targeting snakes and some type of resistance to the venoms of the snakes they preyed on, associating these characteristics with the development of ophiophagy. In the Neotropics, more precisely in the Dipsadidae family, there are several ophiophagous species. The genus Erythrolamprus (Tribe Xenodontini) and the genera Clelia and Boiruna (Tribe Pseudoboini) contain species that are specialists in snakes. However, due to their relatively low medical relevance, they have been poorly studied and there is scarce information about their venoms and possible resistance factors or mechanisms. In the present work, the toxin composition of the venom gland transcriptome of 8 genera and 19 species of the tribe Pseudoboini and 3 genera and 8 species of the tribe Xenodontini was analyzed. In addition to being the first compositional analysis of the venom of the two tribes, a new type of enzymatic toxins exclusive to the Dipsadidae family (the svMMPs) was identified and characterized in the analyzed samples, as well as high expression levels of a type of phospholipases A2 in some species of the Pseudoboini tribe was detected. On the other hand, comparisons between liver transcriptomes and plasma proteomes of ophiophagous and non-ophiophagous species of the tribe Pseudoboini allowed identifying high expression levels of several types of toxin inhibitors. However, the occurrence of overexpression of these inhibitors in ophiophagous species was not detected. The analyzes revealed, in a broad scale, the evolutionary novelties present in the compositional profile of the venoms of the two tribes and verified the occurrence of plasma toxin inhibitors in the analyzed species.