Intraspecific variation in the venoms of the South American rattlesnake (Crotalus durissus terrificus)

The venom of eight individual Crotalus durissus terrificus snakes from the State of Minas Gerais, Brazil, in addition to pooled venom from Butantan In stitute, were compared. Snakes were captured in distinct locations, some of them 600 km apart: Conselheiro Lafaiete, Entre Rios de Minas, Itauna, Itap ecerica, Lavras, Patos de Minas, Paracatu, and Santo Antonio do Amparo. The crude venoms were tested for proteolytic, phospholipase A2, platelet aggre gating, and hemagglutinating activities. The venoms were also analyzed by p olyacrylamide gel electrophoresis (PAGE) and isoelectric focusing (IEF). Ch romatographic patterns of venom proteins on both gel-filtration and anion-e xchange chromatographies were also performed. All venoms presented high pho spholipase A2 and platelet-aggregating activities, but only minimal hemaggl utinating or proteolytic activities were found. Gel-filtration chromatograp hy showed a characteristic profile for most venoms where four main peaks we re separated, including the typical ones where convulxin and crotoxin were identified; however, peaks with high amounts of lower molecular weight prot eins were found in the venoms from the Santo Antonio do Amparo location and Butantan Institute, characterizing these venoms as crotamine positive. Ani on-exchange chromatographies presented a similar protein distribution patte rn, although the number of peaks (up to ten) distinguished some Venom sampl es. Consistent with these results, polyacrylamide gels that were silver sta ined after venom separation by PAGE or IEF presented a similar qualitative band distribution, although a quantitative heterogeneity was detected among venoms. Our results suggest that the variability found in venom components of C. d. terrificus venoms captured in Minas Gerais State may be genetical ly inherited and/or environmentally induced. (C) 2000 Elsevier Science Inc. All rights reserved.