Bioassay of Solubilized Bacillus thuringiensis var. Israelensis Crystals by Attachment to Latex Beads

Abstract
Solubilized crystals of B. thuringiensis var. israelensis [a biological cointrol agent] were 7000 times less toxic to Aedes aegypti larvae than intact crystals, presumably because mosquito larvae are filter feeders and selectively concentrate particles while excluding H2O and soluble molecules. A procedure is described whereby soluble toxins are adsorbed to 0.8 .mu.m latex beads, with retention of toxicity. The latex bead assay should make it possible to analyze the structure and mode of action of the mosquito toxin.