[Toxic action of the polyene antibiotic levorin on the superproducer Streptomyces levoris].

Along with an increase in the activity of a superproductive strain of Str. levoris there was observed in its population an increase in the number of low active cells sensitive to high concentrations of the own antibiotic. Levorin had an especially high toxic action on viability and antibiotic activity of the low productive strain 78/19 as compared to the highly productive strain 78/72.

[Lethal and mutagenic action of N-nitroso-N-methylbiuret on the producers of levorin, amphotericin and mycoheptin].

The lethal and mutagenic effect of N-nitrozo-N-methylbiuret (NMB) on the organisms producing levorin, amphotericin B and mycoheptin was studied. The mutagen effect depended on the dose, culture and physiological state of the spores. NMB had a low mutagenic effect on the levorin-producing organism characterized by high activity and genetic homogenicity with respect to the colony morphology and antibiotic production.

[Selective action of novobiocin on Act. levoris, the producer of levorin and levoristatin].

The effect of sodium novobiocin on Act. levoris, strain LIA 0868 producing levorin and levoristatin was studied. High lethal effect of the antibiotic on Act.

[Comparative study of the action of streptomycin on the variability of levorin and amphotericin B producers].

The study of the effect of streptomycin on viability of Act. levoris, strain LIA=0868 producing levorin and Act. nodosus, strain LIA-0861 producing amphotericin B showed that streptomycin had a lethal effect which increased with increasing of its concentration from I to 6 gamma/ml.