[Biosynthesis of nactinic compounds by population variants of macrotetrolide-producing streptomycetes].

Strains of Streptomyces chrysomallus subsp. macrotetrolidi and soil isolates of Streptomyces spp. producing ammonium specific agents were studied and correlation between the synthesis of nactinic acids and their oligomers and the hydrophobic nature of the active variant in the streptomycete population was shown.

[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.

[Biologically active substances formed by a number of strains of the actinomycin C producer--Streptomyces chrysomallus].

Biologically active substances produced by some strains of S. chrysomallus and their mutants with different levels of the differentiation were studied. Along with actinomycin C the strains produced macrotetrolides, bacteriocins and A factor-like substances.

[Stability of Escherichia coli to the membranotropic antibiotic gramicidin S].

The work was aimed at studying the effect of gramicidin S on the intact cells, spheroplasts and membrane specimens of Escherichia coli K12S with the natural resistance to this antibiotic. The resistance was shown to be caused by the barrier properties of the cell wall: the spheroplasts were highly sensitive to the lytic action of gramicidin S. The differences in the sensitivity to gramicidin S of substrate oxidation carried by the membranes of E.

[Action of thomicide on bacterial cells. The membranotropic activity of thomicide].

It was shown that a combined drug thomicide impaired permeability of cell membranes in Micrococcus luteus 2665 and Staphylococcus aureus 209P inducing production of substances with the absorption maxima at 260 nm. Active lysis of the M. luteus 2665 protoplasts under the action of thomicide used in a dose of at least 60 micrograms per 1 mg of the protoplast proteins was observed.