A PROTEIN COMPLEX FROM CHORISTONEURA-FUMIFERANA GUT-JUICE INVOLVED INTHE PRECIPITATION OF DELTA-ENDOTOXIN FROM BACILLUS-THURINGIENSIS SUBSP SOTTO

A 75 kDa protein from spruce budworm (Choristoneura fumiferana) gut-ju ice has been isolated and shown to cause a specific precipitation of t he delta-endotoxin from Bacillus thurirtgiensis subsp, soffo. This 75 kDa protein, separated by either column chromatography or SDS-PAGE, ca used precipitation of the sotto toxin in both agarose diffusion gels a nd the PAGE gels, The precipitation event leads to limited proteolysis of the toxin and loss of larval toxicity, SDSPAGE analysis of the pre cipitated toxin indicates that proteolysis of the toxin is not a prere quisite for precipitation, The protein responsible for precipitation, exhibits elastase-like adtivity and appears to be a complex which part ially dissociates during boiling in SDS-PAGE sample buffer, Gut-juice from gypsy moth, forest tent caterpillar and white mark tussock moth a lso precipitated 6-endotoxin, but silkworm gut-juice gave a much weake r response, These results provide further evidence that, in the larval gut, differential processing of 6-endotoxin may play a role in the ex pression of activity towards various insect larvae,