Cry1Ac protoxin from Bacillus thuringiensis sp kurstaki HD73 binds to surface proteins in the mouse small intestine

Bacillus thuringiensis (Bt), considered a safe insecticide, produces insect icidal proteins named Cry during sporulation, which possess exceptional imm unological properties. In this work using an immunohistochemical test we de monstrated that Cry1Ac protoxin (pCry1Ac) binds to the mucosal surface of t he mouse small intestine. Ligand blot assay allowed us to detect, under den aturing conditions, six pCry1Ac-binding polypeptides present in brush borde r membrane vesicles isolated from the small intestine. Moreover, this prote in induced in situ temporal changes in the electrophysiological properties of the mouse jejunum. The data obtained indicate a possible interaction in vivo of Cry proteins with the animal bowel which could induce changes in th e physiological status of the intestine. (C) 2000 Academic Press.