[Antibiotic properties of cultures of the Streptomyces coelicolor group that suppress the growth of strains of the same species]. / Antibioticheskie svoistva kul'tur gruppy Streptomyces coelicolor, ugnetaiushchie rost shtammov togo zhe vida.

Antimicrobial spectrum of 45 cultures of the S. coelicolor group with respect to closely related strains and other streptomycete species was studied. The spectrum of 7 cultures was narrow and they inhibited closely related strains and certain streptomycete species. These cultures produced antibiotic substances of bacteriocin-like nature. The bacteriocin-like substances of the cultures differed in sensitivity to temperature and proteolytic enzymes and capacity for dialysis through cellophane membranes. Biosynthesis of the antibiotic substances increased after exposure to UV light.

[Isolation and characteristics of Saccharomyces cerevisiae strains with increased sensitivity to detergents]. / Poluchenie i kharakteristika shtammov drozhzhei Saccharomyces cerevisiae s povyshennoi chuvstvitel'nost'iu k detergentam.

The yeast mutants possessing enhanced sensitivity to detergents were obtained after treatment with ethyl methanesulfonate. The whole set of mutants may be divided into three groups, according to sensitivity to: cetylthreemethylammonium chloride detergents and dyes of the ethidium bromide type, detergents, dyes and antibiotics (gramycidin C and actinomycin D). The genetic analysis performed indicated that more than one gene are responsible for sensitivity. On the basis of the test for allelism mutants were distributed into three groups. It was shown that ethidium bromide is far more potent inducer of cytoplasmic petites in detergent-sensitive than in wild-type strains.

[Mutagenic activity of the fungicide captan]. / K voporsu o mutagennoi aktivnosti fungitsida kaptana.

A complex study of mutagenic activity of captan (a fungicide) in a series of standard test-systems has shown that the preparation induces gene mutations in certain Salmonella indicator strains (without metabolic activation), increases the frequency of mitotic crossing-over and gene conversion in yeasts (Saccharomyces), possesses a weak cytogenetic action on bone marrow cells in experimental animals, manifests no cytogenetic effect in the lymphocyte culture of human peripheral blood (including a system of microsomal activation). Genetic activity of captan cannot be a limiting criterion of its harmfulness.

[Effect of nitrosourea in small doses on the frequency of mutation in Salmonella typhimurium]. / Vliianie nitrozomocheviny v malykh dozakh na chastotu mutatsii u Salmonella typhimurium.

The effect of N-nitroso-N-methylurea (NMU), N-nitroso-N,N'-dimethylurea (NDMU) and N-nitroso-N-ethylurea (NEU) at doses less than 100 mkg/ml on mutability of Salmonella typhimurium strains of Ames' system (G-46, TA-1950, TA-1535, TA-100, TA-1538) has been studied. NMU and NEU at doses of 5-10 mkg/ml have been found to increase the survival and decrease the number of reversions from auxotrophity in histidine to prototrophity. The effect of given doses of NMU and NEU on bacteria repair activity has been shown. The role of pk M101 plasmide in this process is being discussed. NDMU in contrast to NMU and NEU induces read frome shift mutations and exhibits high mutagenous activity at all doses examined.

[Effect of nonmutagenic doses of 1,4-bis-diazoacetylbutane on Streptomyces griseus]. / Vliianie na Streptomyces griseus nemutagennykh doz 1,4-bis-diazoatsetilbutana.

Streptomyces griseus 15 was subjected to the action of 1,4-bis-diazoacetyl butane (DAB) taken at concentrations of 10 to 50,000 micrograms/ml. Small doses (10-100 micrograms/ml) of DAB had no mutagenic action and activated the cultural growth (the viability and the survival rate of spores increased on solid media, while the biomass yield rised in liquid media). Experiments were conducted using the method of orthogonal planning of a bifactorial experiment, and the role of the exposure time rised with a decrease in the mutagen concentration.

[Comparative study of the mutagenic activity of organophosphate insecticides on bacteria]. / Sravnitel'noe izuchenie mutagennoi aktivnosti nekotorykh fosfororganicheskikh insektitsidov na bakteriiakh.

Mutagenic activity of the organo-phosphorus insecticides, metaphos, phosphamide and carbophos, on indicator Salmonella typhimurium TA-1535 strain is shown which is determined without metabolic activation. It is established that all the three preparations induce direct mutations in Pseudomonas aeruginosa. The quantity of visible mutations increases with the prolongation of exposure time and the insecticide concentration. Metaphos and phosphamide induced auxotrophic mutations. Phosphamide has the highest mutagenic activity in the assays with bacterial systems.