Study of the protein and functional composition of the venom of elderly snakes of the subspecies Crotalus durissus terrificus in the vivarium of the Herpetology Laboratory at Instituto Butantan

• Grant number: 22/05593-9
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: December 01, 2022
• End date: November 30, 2023
• Field of knowledge: Biological Sciences - Physiology - Compared Physiology
• Principal Investigator: Anita Mitico Tanaka-Azevedo
• Grantee: Mariana Almeida Costa
• Host Institution: Instituto Butantan. Secretaria da Saúde (São Paulo - Estado). São Paulo , SP, Brazil

Abstract

Snakes of the genus Crotalus have great medical importance for Brazil due to the number of snakebites caused by these animals. It is the second genus responsible for snakebites and the frequency of recorded deaths. In Latin America we can find Crotalus durissus, a species whose distribution is wide and well determined, inhabiting mainly arid, semi-arid areas and open fields. The subspecies Crotalus durissus terrificus is the most abundant in Brazil and, in its venom, the main toxins found are crotoxin, crotamine, convulxin and gyroxin. Such toxins are capable of severely affecting the physiological processes of the organism, through neurotoxic, myotoxic effects and, in cases of late and/or inadequate medical treatment, renal failure. Although there is a lot of information about the protein profile of the venom of this species, intraspecific compositional variations are common and may occur due to geographic distribution, diet and age. Due to changes in habits throughout life, such as in food, for example, the chemical composition of poisons may undergo changes, which are of great relevance for research. Taking into account the clinical scope, it is extremely important to know the compositional differences of Crotalus durissus terrificus venoms so that snakebites are treated properly or even so that the antivenom sera are reformulated for a more effective composition. The in-depth study of venom variations has an impact both on the research of the venoms themselves and on the quality of aid administered in the event of an snakebite, including the selection of serum and the selection of individuals used for its production. To achieve this objective, the following methodologies will be carried out: protein dosage, polyacrylamide gel electrophoresis in the presence of SDS, determination of enzymatic activities (L-amino acid oxidase, phospholipase A2 and proteolytic on casein), high performance chromatography, minimal coagulant dose and enzyme immunoassay. Thus, the results of this project will contribute to the elucidation of the composition and activities of the venoms of Crotalus durissus terrificus senis snakes.