[Plasmids from certain strains of Streptomyces chrysomallus].

Plasmid content has been studied in a number of Streptomyces chrysomallus strains producers of actinomycin C. The plasmids pSCH2 and pSCH3 have been isolated from nocardia-like mutants of Streptococcus chrysomallus BKM Ac-590 that are producing antibiotics macrotetrolides, bacteriocins and an inducer analogous to A-factor in addition to actinomycin. The size of the plasmids is 13.4 and 15.1 kb as found by restriction analysis. Plasmids differ in deletion and content in the cultures. The ability of the strains to produce antibiotics depends on plasmid content.