[Changes in Bacillus pumilus antibiotic activity and sensitivity with integration and disintegration of plasmid pPL 7065].

The role of plasmid pPL 7065 in the control of the antibiotic production and sensitivity in Bac. pumilus was studied with the use a plasmid-free strain and strains containing the plasmid in the cells in a free or chromosome-integrated state. It was found that all the strains had antibiotic activity only with respect to a limited number of gram-positive bacteria. Still, the antibiotics produced by them differed in the antibacterial spectrum. The antibiotic produced by the plasmid-free strain had a broader spectrum. It was shown that the bacteria with the plasmid in th free state were sensitive to the antibiotics produced by the plasmid-free strain for the strain or the strain with the chromosome-integrated plasmid. It was suggested that plasmid pPL 7065 played the role of a modifier of the antibiotic activity and sensitivity in Bac. pumilus and carried no genetic information for the control of the antibiotic synthesis. Their formation is determined by the chromosome genes.