BnSP-7 toxin, a basic phospholipase A2 from Bothrops pauloensis snake venom, interferes with proliferation, ultrastructure and infectivity of Leishmania (Leishmania) amazonensis.

This paper reports the effects of BnSP-7 toxin, a catalytically inactive phospholipase A2 from Bothrops pauloensis snake venom, on Leishmania (Leishmania) amazonensis. BnSP-7 presented activity against promastigote parasite forms both in the MTT assay, with IC50 of 58.7 µg mL(-1) of toxin, and a growth curve, inhibiting parasite proliferation 60-70% at concentrations of 50-200 µg mL(-1) of toxin 96 h after treatment. Also, the toxin presented effects on amastigotes, reducing parasite viability by 50% at 28.1 µg mL(-1) and delaying the amastigote-promastigote differentiation process. Ultrastructural studies showed that BnSP-7 caused severe morphological changes in promastigotes such as mitochondrial swelling, nuclear alteration, vacuolization, acidocalcisomes, multiflagellar aspects and a blebbing effect in the plasma membrane. Finally, BnSP-7 interfered with the infective capacity of promastigotes in murine peritoneal macrophages, causing statistically significant infectivity-index reductions (P < 0.05) of 20-35%. These data suggest that the BnSP-7 toxin is an important tool for the discovery of new parasite targets that can be exploited to develop new drugs for treating leishmaniasis.

Biological and proteomic characterization of the venom from Peruvian Andes rattlesnake Crotalus durissus.

The Peruvian rattlesnake Crotalus durissus is a venomous species that is restricted to the Peruvian Departments of Puno and Madre de Dios. Although clinically meaningful in this region, Crotalus durissus venom composition remains largely elusive. In this sense, this work aimed to provide a primary description of Peruvian C. durissus venom (PCdV). The enzymatic activities (SVMP, SVSP, LAAO, Hyaluronidase and PLA2) of PCdV were analyzed and compared to Brazilian Crotalus durissus terrificus venom (BCdtV). PCdV showed higher PLA2 activity when compared to the Brazilian venom. PCdV also showed cytotoxicity in VERO cells. For proteomic analysis, PCdV proteins were separated by HPLC, followed by SDS-PAGE. Gel bands were excised and tryptic digested for MALDI-TOF/TOF identification. Approximately 21 proteins were identified, belonging to 7 families. Phospholipases A2 (PLA2, 66.63%) were the most abundant proteins of the venom, followed by snake venom serine proteinases (SVSPs, 13.37%), C-type lectins (Snaclec, 8.98%) and snake venom metalloproteinases (SVMPs, 7.13%), crotamine (2.98%) and phosphodiesterase (PDE, 0.87%). Moreover, antivenom recognition assays indicated that both Brazilian and Peruvian antivenoms recognize PCdV, indicating the presence of antigenically related proteins in crotalic venoms. The results reported here, may impact in the venom selection for the production of effective Pan-American crotalic antivenom.