[Natural and UV-induced variability of the producer of telavimycin Streptomyces levoris, Krass, strain 243].

The experimental data showed that the morphological variation of the culture of strain 243 of Streptomyces levoris, Krass, producing telavimycin (antibiotic 243) resulted in the formation of three morphological types differing in some features from the initial culture. Cultures of the type I and II colonies were most promising for selection. Strains producing higher yields of the antibiotic as compared to the initial strain 243 were selected from these cultures. After exposure of the spores of strain 243-96 to UV light in a dose of 500 erg/mm2 a highly productive strain 243-197 was isolated. The activity of this strain is 51 per cent higher than that of strain 243-96.