Unraveling the antifungal activity of a South American rattlesnake toxin crotamine

Abstract

Crotamine is a highly basic peptide from the venom of Crotalus durissus terrificus rattlesnake. Its common gene ancestry and structural similarity with the beta-defensins, mainly due to an identical disulfide bond pattern, stimulated us to assess the antimicrobial properties of native, recombinant, and chemically synthesized crotamine. Antimicrobial activities against standard strains and clinical isolates were analyzed by the colorimetric microdilution method showing a weak antibacterial activity against both Gram-positive and Gram-negative bacteria [MIC (Minimum Inhibitory Concentration) of 50->200 mu g/mL], with the exception of Micrococcus luteus [MIC ranging from 1 to 2 mu g/mL]. No detectable activity was observed for the filamentous fungus Aspergillus fumigatus and Trichophyton rubrum at concentrations up to 125 mu g/mL. However, a pronounced antifungal activity against Candida spp., Trichosporon spp., and Cryptococcus neoformans [12.5-50.0 mu g/mL] was observed. Chemically produced synthetic crotamine in general displayed MIC values similar to those observed for native crotamine, whereas recombinant crotamine was overridingly more potent in most assays. On the other hand, derived short linear peptides were not very effective apart from a few exceptions. Pronounced ultrastructure alteration in Candida albicans elicited by crotamine was observed by electron microscopy analyses. the peculiar specificity for highly proliferating cells was confirmed here showing potential low cytotoxic effect of crotamine against nontumoral mammal cell lines (HEK293, PC12, and primary culture astrocyte cells) compared to tumoral B16F10 cells, and no hemolytic activity was observed. Taken together these results suggest that, at low concentration, crotamine is a potentially valuable anti-yeast or candicidal agent, with low harmful effects on normal mammal cells, justifying further studies on its mechanisms of action aiming medical and industrial applications. (C) 2012 Elsevier Masson SAS. All rights reserved.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)University of Maryland Baltimore County Designated Research Initiative FundUniversidade Federal de São Paulo UNIFESP, Dept Farmacol, BR-04044020 São Paulo, BrazilUniversidade Federal de São Paulo UNIFESP, Dept Med, BR-04044020 São Paulo, BrazilUniv São Paulo, Dept Bioquim & Imunol, BR-14049 Ribeirao Preto, BrazilUniv Maryland, Sch Med, Inst Human Virol, Baltimore, MD 21201 USAUniv Maryland, Dept Biochem & Mol Biol, Baltimore, MD 21201 USAUniversidade Federal de São Paulo UNIFESP, Dept Bioquim, BR-04044020 São Paulo, BrazilInst Butantan, Lab Bioquim & Biofis, BR-05503900 São Paulo, BrazilUniversidade Federal de São Paulo UNIFESP, Dept Ginecol, BR-04044020 São Paulo, BrazilCBA, Lab Bioquim & Biol Mol, Manaus, Amazonas, BrazilUniv Maryland Baltimore Cty, Dept Chem & Biochem, Baltimore, MD 21250 USAInst Butantan, Ctr Toxinol Aplicada CAT CEPID, BR-05503900 São Paulo, BrazilUniversidade Federal de São Paulo UNIFESP, Dept Farmacol, BR-04044020 São Paulo, BrazilUniversidade Federal de São Paulo UNIFESP, Dept Med, BR-04044020 São Paulo, BrazilUniversidade Federal de São Paulo UNIFESP, Dept Bioquim, BR-04044020 São Paulo, BrazilUniversidade Federal de São Paulo UNIFESP, Dept Ginecol, BR-04044020 São Paulo, BrazilWeb of Scienc