INSECTICIDAL AND HEMOLYTIC CHARACTERIZATION OF THE FRACTIONS OF BACILLUS-THURINGIENSIS SUBSP ISRAELENSIS TOXIN

Solubilized crystal protein of Bacillus thuringiensis subsp. israelens is was fractionated by Sephadex G-200 column chromatography and assaye d against mosquito larvae and human erythrocytes. The fraction contain ing the major polypeptides 130 kDa, 68 kDa and the polypeptide 35 kDa was found to be nonhaemolytic but to retain nearly full toxicity. The fractions that contained also the 27 kDa protein showed haemolytic act ivity and their mosquitocidal toxicity was approximately in proportion to the quantity of the 68 kDa protein. The results suggested that the polypeptides 130 kDa and 68 kDa were responsible for the dipteran tox icity and the 27 kDa polypeptide had the haemolytic activity. However, it is possible that the 27 kDa protein may contribute, as a synergist ic factor to the larvicidal activity.