Ex vivo cytotoxicity of the Bacillus thuringiensis Cry4B delta-endotoxin to isolated midguts of Aedes aegypti larvae.

The pathological effect of the Bacillus thuringiensis Cry delta- endotoxins on susceptible insect larvae had extensive damage on the midgut epithelial cells. In this study, an ex vivo assay was devised for assessing the insecticidal potency of the cloned Cry4B mosquito-larvicidal protein that is expressed in Escherichia coli. Determination of toxicity was carried out by using a cell viability assay on the midguts that were dissected from 5-day old Aedes aegypti mosquito larvae.