In vivo binding of the Cry11bb toxin of Bacillus thuringiensis subsp medellin to the midgut of mosquito larvae (Diptera : Culicidae)
Autor(es): Ruiz, LM; Segura, C; Trujillo, J; Orduz, S
Resumo: Bacillus thuringiensis subsp. medellin produces numerous proteins among which 94 kDa known as Cry11Bb, has mosquitocidal activity. The mode of action of the Cry11 proteins has been described as similar to those of the Cry1 toxins nevertheless, the mechanism of action is still not clear In this study we investigated the in vivo binding of the Cry11b toxin to the midgut of the insect species Anopheles albimanus, Aedes aegypti, and Culex quinquefasciatus by immunohistochemical analysis. Spodoptera frugiperda was included as negative control.The Cry11Bb protein was detected on the apical microvilli of the midgut epithelial cells, mostly on the posterior midgut and gastric caeca of the three mosquito species. Additionally, the toxin was detected in the Malpighian tubules of An. albimanus, Ae. aegypti, Cx. quinquefasciatus, and in the basal membrane of the epithelial cells of Ae. aegypti midgut. No toxin accumulation was observed in the peritrophic membrane of any of the mosquito species studied. These results confirm that the primary site of action of the Cry11 toxins is the apical membrane of the midgut epithelial cells of mosquito larvae.
Palavras-Chave: Diptera; Immunohistochemistry; In Vivo Binding; Bacillus Thuringiensis; Cry11Bb Toxin
Imprenta: Memorias do Instituto Oswaldo Cruz, v. 99, n. 1, p. 73-79, 2004
Identificador do objeto digital: 10.1590/S0074-02762004000100013
Descritores: Aedes aegypti - Larvicide
Data de publicação: 2004
