Transfer of shuttle vectors containing Bacillus thuringiensis toxin gene into wild-type B. cereus, B. brevis and B....

Gram positive and negative bacterial shuttle vectors carrying Bacillus thuringiensis (B.t.) toxin gene were introduced by electroporation into wild-type Bacillus cereus, B. brevis and B. subtilis. The transformation efficiencies for these bacteria were around 10(1)-10(4) transformants per micrograms DNA based on the numbers of neomycin- and ampicillin-resistant colonies produced. The structure of the transferred plasmids proved identical with the original ones both in size and restriction pattern. Toxicity assays showed that the transformants gave a mortality of 90-100% against caterpillar of Heliothis assulta, indicating that the gene function was not changed by electroporation.