Crotamine in Crotalus durissus: distribution according to subspecies and geographic origin, in captivity or nature

 

Lídia J. Tasima1,2, Caroline Serino-Silva1,2, Daniela M. Hatakeyama1,2, Erika S. Nishiduka3, Alexandre K. Tashima3, Sávio S. Sant’Anna1, Kathleen F. Grego1, Karen de Morais-Zani1,2, Anita M. Tanaka-Azevedo1,2

 

1 Laboratory of Herpetology, Butantan Institute, São Paulo, SP, Brazil.

2 Interinstitutional Postgraduate Program in Biotechnology (PPIB – IPT, IBU and USP), University of São Paulo (USP), São Paulo, SP, Brazil.

3 Department of Biochemistry, Federal University of São Paulo (Unifesp), São Paulo, SP, Brazil.

 

Abstract

Background: Crotalus durissus is considered one of the most important species of venomous snakes in Brazil, due to the high mortality of its snakebites. The venom of Crotalus durissus contains four main toxins: crotoxin, convulxin, gyroxin and crotamine. Venoms can vary in their crotamine content, being crotamine-negative or -positive. This heterogeneity is of great importance for producing antivenom, due to their different mechanisms of action. The possibility that antivenom produced by Butantan Institute might have a different immunorecognition capacity between crotamine-negative and crotamine-positive C. durissus venoms instigated us to investigate the differences between these two venom groups.

 

Methods: The presence of crotamine was analyzed by SDS-PAGE, western blotting and ELISA, whereas comparison between the two types of venoms was carried out through HPLC, mass spectrometry analysis as well as assessment of antivenom lethality and efficacy.

 

Results: The results showed a variation in the presence of crotamine among the subspecies and the geographic origin of snakes from nature, but not in captive snakes. Regarding differences between crotamine-positive and -negative venoms, some exclusive proteins are found in each pool and the crotamine-negative pool presented more phospholipase A2 than crotamine-positive pool. This variation could affect the time to death, but the lethal and effective dose were not affected.

 

Conclusion: These differences between venom pools indicate the importance of using both, crotamine-positive and crotamine-negative venoms, to produce the antivenom.

 

Keywords: Rattlesnake Snake venom Toxins Venom variation Antivenom

 

Correspondence: anita.azevedo@butantan.gov.br

 

Received: 06 August 2019; Accepted: 06 March 2020; Published online: 06 April 2020