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M R Pogosbekova

Publications and source records attributed to M R Pogosbekova.

2 recordsLinked to original sources

[Intervariant transduction in Bacillus thuringiensis].

This report deals with intervariant transduction in strains of Bacillus thuringiensis subsp, dendrolimus and galleriae with bacteriophage Tg13. This bacteriophage has a broad host range and is of a large DNA molecular mass (40.3 mD). Transducing properties of this bacteriophage were studied in Bacillus thuringiensis var. galleriae using auxotrophic mutants requiring purine and pyrimidine bases or tryptophan as recipients. The frequency of transduction was 10(-5)-10(-6). In order to prove the possibility of intervariant transduction, two series of experiments have been conducted. In the first case, bacteriophage tg13 has been propagated on the prototrophic strain 49-18 (var. dendrolimus), 48gua (var. galleriae) being used as a recipient. In the second case, the prototrophic strain 69-6 (var. galleriae) served as a donor and 49-18-1 trp (var. dendrolimus) - as a recipient. The frequency of heterologous transduction was 10(-7). The positive result obtained in cross-transduction experiments may be explained by common metabolic pathways of purine and pyrimidine bases and amino acids in strains of different serotypes.

Bacillus thuringiensis↗

[Comparative characteristics of spore-forming and asporogenic strains of Bacillus thuringiensis].

Comparative characteristics of sporogenous and asporogenous Bacillus thuringiensis strains is carried out. Asporogenous strains are found to differ from wild type strains in a number of criteria, including colony morphology, character of growth on rich and poor media and UV-sensitivity. Sporogenous strains form R colonies, they are more stable and more rare produce variants forming S colonies. S colonies are typical for asporogenous mutants, and under the cultivation in unfavourable conditions (elevated temperature, a shift of pH, a change of an incubation regime) asporogenous strains dissociate with a high frequency into R form. Initial strains, which are multiple auxotrophs, under certain conditions can form "prototrophic" revertants which are unstable when incubated on rich media. Suppressor mutation is supposed to be a possible mechanism of the origination of "prototrophs".

Bacillus thuringiensis↗