Proteomic and functional characterization of the venom of two species of snakes from the genus Bothrops submitted to diet change

Author(s)

Nathália da Costa Galizio

• Document type: Master's Dissertation
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto de Ciências Biomédicas (ICB/SDI)
• Defense date: 2021-04-27

Examining board members

Karen de Morais Zani; Cristiane Rodrigues Guzzo Carvalho; Fernanda Calheta Vieira Portaro; Alexandre Keiji Tashima

• Advisor: Karen de Morais Zani

Abstract

Snake venoms are the most studied animal toxins. Its composition is complex, being composed mainly of proteins, which correspond to approximately 90% of its dry weight. The venom proteins are subject to Darwinian evolution and the variation in the composition of the venom is observed at different taxonomic levels. Studies consistently demonstrate that there are large variations in the composition of snake venoms between different species and even within the same species. These differences can be due to different factors, including sex, age, geographic distribution and diet. The variation in the venom composition due to diet may be related to the snake\'s specialization to different prey. However, the correlation between diet and venom composition and activities is still a controversial topic. Therefore, the objective of this work is to investigate the influence of the diet on the composition, and biochemical and biological activities of the venom from snakes of the species Bothrops moojeni and B. alternatus. For this, the snakes of both species had their diet changed from mammals (mice or rats), the standard diet used in the maintenance of the snakes at the Laboratory of Herpetology of the Butantan Institute, to amphibians (Lithobates catesbeianus) for one year and then, returned to the diet based on mammals. Regarding snakes, it was noted that the species B. moojeni showed less rejection of feeding, without episodes of regurgitation or death due to the diet. B. alternatus, on the other hand, had many episodes of regurgitation, in addition to severe oral problems, including stomatitis with the presence of pus. Few differences were observed in the electrophoretic and chromatographic profile of B. moojeni, but the snakes of the species B. alternatus showed a more intense protein band of ~15 kDa in the final venom, but which remained after returning to the diet base on mammals. In addition, there were new chromatographic peaks in high performance liquid chromatography (HPLC), especially in female venoms, which was not observed in B. moojeni. Regarding the enzymatic activities, the most notable differences were in the LAAO and PLA2 activities of the B. alternatus snakes, whereas the B. moojeni venom showed few changes. In vivo assays demonstrated a decrease in lethal activity in mice and an increase in amphibians for both species. Hemorrhagic and edematogenic activities showed a decrease with amphibian-based feeding in both species, but there was a return to the initial activity only in B. moojeni species. Thus, the results of this work corroborate the influence of the diet on the composition and function of the snake venom, indicating a phenotypic plasticity. (AU)

• FAPESP's process: 18/14724-4 - Proteomic and functional characterization of the venom of two species of snakes of the genus Bothrops submitted to diet change
• Grantee: Nathália da Costa Galizio
• Support Opportunities: Scholarships in Brazil - Master