[Action of the delta-endotoxin of Bacillus thuringiensis var. israelensis on cultured cells from Aedes aegypti L].

The effects of Bacillus thuringiensis var. israelensis delta-endotoxin were investigated on a cell culture of Aedes aegypti with the electron microscope. The ultrastructural changes following intoxication were: disintegration of endoplasmic reticula by the formation of spherical structures; condensation and then swelling of mitochondria with disappearance of internal cristae; frequent dilatation of the perinuclear space; cellular lysis. The action of a metabolic inhibitor, 2,6-dibromophenol (2,6-DBP), was tested for comparison: beyond condensation of mitochondria, no changes in other cell structures were observed. These data seem to indicate that the mode of action of delta-endotoxin is quite different from that of 2,6 DBP.