[Study of the nature of determinants for synthesis of delta-endotoxin and beta-exotoxin in Bacillus thuringiensis subsp. thuringiensis strains--bitoxybacillin producers].

The growth of Bacillus thuringiensis subsp. thuringiensis strains (BT) 202, 1140, 98 producing bitoxybacillin in the presence of novobiocin, mitomycin C and at high temperature 43 degrees C resulted in obtaining of the mutants for the synthesis of crystalline protein (Cry) and exotoxin (Exo). Analysis of the plasmid content of the mutants has shown the Cry Exo phenotyre to correlate with the loss of 55 MD plasmid in the strain BT202 and the loss of 60MD plasmid in BT1140. The transfer of these plasmids into Bacillus cereus leads to the transfer of endo- and exotoxin production properties. The synthesis of Cry in BT98 is controlled by the 56MD plasmid, while the synthesis of Exo is encoded by the chromosome or plasmid that cannot be eliminated or transferred into other strains. Localization of Cry on the 55 and 56 MD plasmids in BT202 and BT98 is confirmed by the hybridization of the plasmid DNA with the DNA-probe.