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Enzymatic hydrolysis of the crystals of Bacillus thuringiensis by the proteases of Pieris brassicae II. Toxicity of the different fractions of the hydrolysate for larvae of Pieris brassicae

1967; Elsevier BV; Volume: 9; Issue: 3 Linguagem: Inglês

10.1016/0022-2011(67)90066-3

1096-0805

Marguerite M. Lecadet, D. Martouret,

Insect and Arachnid Ecology and Behavior

Dispersion of the crystalline structure of the parasporal inclusion of Bacillus thuringiensis, under the action of Pieris brassicae proteases, liberates soluble substances that are directly toxic by injection into the hemocoel of caterpillars (although the crystal itself is only active per os) in doses smaller than 1 μg/g of larva. Following the fractionation of the hydrolysate, it appears that the toxic factor, unmasked by the rupture of peptide bonds, can be carried by the proteins as well as by peptides with a molecular weight of the order of 5,000. The sensitivity of the different fractions to thermal denaturation seems to indicate that a tertiary structure is necessary for the action of the toxic factor.