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 insecticidal proteins named Cry
during sporulation, which possess exceptional immunological
properties. In this work using an immunohistochemical
test we demonstrated that Cry1Ac protoxin
(pCry1Ac) binds to the mucosal surface of the
mouse small intestine. Ligand blot assay allowed us to
detect, under denaturing conditions, six pCry1Acbinding
polypeptides present in brush border membrane
vesicles isolated from the small intestine. Moreover,
this protein 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 the physiological status of the

The full report is in Biochemical and Biophysical Research Communications 271, 54–58 (2000). It is also available online at

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