[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. While the lethal effect of streptomycin on the above cultures was comparatively the same, it had a selective effect on the levorin-producing organism and a marked inhibitory effect on the amphotericin B-producing organism. The selective effect of streptomycin was evident from inhibition of some types of the morphological mutants and variants characterized by a high level of levorin production and from selection of streptomycin-resistant variants. The inhibitory effect of streptomycin was evident from a marked increase in the number of the morphologically changed colonies and variants characterized by a low level of the antibiotic production.