Autor(es): Opota, Onya; Charles, Jean-Francois; Warot, Sylvie; Pauron, David; Darboux, Isabelle

Resumo: The binary toxin (Bin) from Bacillus sphaericus exhibits a highly insecticidal activity against Culex and Anopheles mosquitoes. The cytotoxicity of Bin requires an interaction with a specific receptor present on the membrane of midgut epithelial cells in larvae. A direct correlation exists between binding affinity and toxicity. The toxin binds with high affinity to its receptor in its primary target, Culex pipiens, and displays a lower affinity to the receptor in Anopheles gambiae, which is less sensitive to Bin. Although the Bin receptor has previously been identified and named Cpml in C. pipiens, its structure in Anopheles remains unknown. In this study, we hypothesize that the Anopheles Bin receptor is an ortholog of Cpml. By screening the Anopheles genomic database, we identified a candidate gene (Agm3) which is expressed primarily on the surface of midgut cells in larvae and which functions as a receptor for Bin. A Cpml-like gene is also present in the Bin-refractory species Aedes aegypti. Overall, our results indicate that the three mosquito genes examined share a very similar organization and are strongly conserved at the amino acid level, in particular in the NH2-terminus, a region believed to contain the ligand binding site, suggesting that relatively few amino acids residues are critical for high affinity binding of the toxin. (C) 2007 Elsevier Inc. All rights reserved.

Palavras-Chave: Anopheles Gambiae; Receptor; Binary Toxin; Bacillus Sphaericus; Biopesticide

Imprenta: Comparative Biochemistry and Physiology B-Biochemistry & Molecular Biology, v. 149, n. 3, p. 419-427, 2008

Identificador do objeto digital: 10.1016/j.cbpb.2007.11.002

Descritores: Aedes aegypti - Molecular screening ; Aedes aegypti - Public health

Data de publicação: 2008

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