... At sporulation, in addition to spores, crystals of protein, the delta-endotoxin, are also formed. Form: Suspended solid in a fermentation ... action. Following ingestion, the crystals of endotoxin are solubilised; the epithelial cells of the gut are damaged, insects stop feeding ... on B. thuringiensis-containing pesticides demonstrate that isolates are not toxic or pathogenic. No adverse effects observed ...