[The use of growth stimulants in the bacteriologic diagnosis of Yersinia]. / Ispol'zovanie nekotorykh stimuliatorov rosta v bakteriologicheskoi diagnostike iersiniozov.

The effects of K. S. Karpuzidi's stimulants (0.5-1 percent) and of para-amino benzoic acid (0.1-05 mM) on the growth and multiplication of 3 Yersinia pseudotuberculosis, 1 Y. enterocolitica strains, and E. coli nonpathogenic strain were examined. Karpuzidi's stimulant was found to selectively stimulate Yersinia cell growth and inhibit Escherichia development in conditions unfavorable for these bacteria. Para-amino benzoic acid intensively stimulated the growth of both Yersinia and Escherichia. When Karpuzidi's stimulant was added to the accumulation medium after frosting-defrosting, it increased Yersinia harvest in cultures isolated from humans 2-3.5 times and that in cultures from the environmental objects 6-7 times. The results of bacteriologic investigation may be obtained 3-5 days sooner.

[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.