Crystal formation peculiarities in pigmented cultures of Bacillus thuringiensis

A direct correlation has been established between pink-colored pigmentation and the production of insecticide crystals (toxins) for some Bacillus thuringiensis (BT) pigmented cultures. This regularity was for the first time determined by us for BT strains of the H3, H10, and H16 serotype. Pigment-free clones of these serotypes do not produce crystals. A correlation was not observed in the case of H14 serotype strains with oval inclusions. The revealed correlation makes it possible to distinguish crystal-yielding colonies in cultures of the above-mentioned serotypes by the availability of pigmentation. This method can serve as an effective express method for the detection of virulent clones, which is especially important if these strains are used for obtaining insecticide preparations.