Navegando por Autor "Eauclaire, Marie France Martin"
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Item Purification, amino-acid sequence and partial characterization of two toxins with anti-insect activity from the venom of the South American scorpion Tityus bahiensis (Buthidae).(2001) Pimenta, Adriano Monteiro de Castro; Eauclaire, Marie France Martin; Rochat, Hervé; Figueiredo, Suely Gomes de; Kalapothakis, Evanguedes; Afonso, Luís Carlos Crocco; Lima, Maria Elena deWe report here the isolation by a two-step chromatographic procedure of two new toxins from the South American scorpion Tityus bahiensis. Their amino-acid sequences and some of their biological features were established. The two toxins have different biological properties. Toxin TbIT-I had almost no activity or pharmacological effects in vertebrate tissues whereas it was lethal to house ¯ies (LD50 80.0 ng/house ¯y). In contrast, Tb2-II was active against both mammals (intracerebroventricular injection of 100 ng/mouse was lethal) and insects (LD50 40.0 ng/house ¯y). The amino-acid sequences of these toxins were established and found to be similar (60±95%) to previously described b-toxins from the Tityus genus. Based on the available comparative information, this study attempts identify possible structure±function relationships that may be responsible for the differences in bioactivity displayed by these toxins.