ISOLATION AND CHARACTERIZATION OF A NOVEL COLEOPTERA-SELECTIVE TOXIN FROM THE VENOM OF BRAZILIAN SCORPION Tityus serrulatus

Andrez, R.M.A., Gomes, P.C., Almeida-Gontijo, M., Kalapothakis, E., Chavez-Olortegui, C., Richardson, M. 

Fundação Ezequiel Dias Belo Horizonte, MG, Brazil. Departamento de Farmacologia Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.

Tityus serrulatus scorpion venom is a rich source of various polypeptides with diverse physiological and pharmacological activities which generally exert their action via target specific modulation of ion channel function. According to their species selectivity sodium channel toxins have been divided into mammalian and insect toxins. depending on their binding affinities and electrophysiological properties, the mammalian toxins are sub-classified into a- and b-toxins and the insect-specific toxins are subdivided into excitatory, depressant and a-insect toxins.  In this work   we investigated the venom of the Brazilian yelow scorpion, T. serrulatus for the purpose of identifying potent insecticidal peptide toxins. A coleoptera-selective toxin has been isolated from T. serrulatus  whole venom by a  combination of conventional gel filtration (Sephadex G50), ion-exchange chromatography (CM Sepharose) and reverse phase HPLC (Vydac C4). This toxin is selectively active on Tenebrio molitor causing flaccid paralysis and death but was non-toxic to mice. As  conclusion this is the first report of a T. molitor selective peptide toxin. Identification of diverse insect selective toxins offer advantages in employing these peptides selectively for pest control.

Supported by: CNPq, INSERM, FAPEMIG.

CORRESPONDENCE TO:

Ricardo Andrez Machado de Ávila, Rua Dr. Mário Magalhães 201, Belo Horizonte, MG, CEP: 31710360, Brasil, Email: r_andrez@yahoo.com.br