[The genetic sequelae of irradiation in mammals (a review of the literature)]. / Aktual'nye aspekty problemy geneticheskikh posledstvii oblucheniia mlekopitaiushchikh (obzor literatury).

The problem of hereditary effects of mammal exposure to ionizing radiation has a 95-year history but to date, no simple final solution has been available. Many papers on this problem specify the dependence of the hereditary effects on dose rate, regime, physical nature of radiation exposure, type, line and age of mammals that were studied. Over many years it was studied mainly as an aspect of hereditary radiation effects in progeny of one irradiated and the second non-irradiated parents. Recently due to the large-scale expansion of ionizing irradiation, it has turned out urgent to study hereditary radiation effects in progeny of both irradiated parents. However, the original studies on this problem are not numerous, and in the summarized articles, the problem practically had no specified presentation.

Auxotrophic mutants in the selection of the rubomycin producer, Actinomyces coeruleorubidus. / Auksotropnye mutanty v selektsii produtsenta rubomitsina----Actinomyces coeruleorubidus.

A total of 351 auxotrophic mutants with different antibiotic activity, including several mutants with activity higher than that of the parent prototrophic strains were obtained under the effect of gamma-rays from 3 prototrophic strains of Act. coeruleorubidus. It was shown that most of the auxotrophic mutants did not preserve the property of biochemical insufficiency on passages on complete media. A mutant strain 1059-32 with activity 2 times higher than that of the prototrophic strain 2-39 and the parent auxotrophic culture was obtained from the revertants. Requirements in 29 growth factors including 17 amino acids, 4 nitrous bases, 8 vitamins and coenzymes were determined in 46 stable auxotrophic mutants isolated. The effect of the specific and non-specific growth factors on the culture antibiotic production was studied.

[Subsequent mutagenesis under the action of UV rays in a culture of Actinomadura carminata, a producer of carminomycin]. / Posledovatel'nyi mutagenez pod deistviem UF-luchei v kul'ture Actinomadura carminata produtsenta karminomitsina

The succession of some markers on the chromosomes of Actinomadura carminata was shown with the method of successive mutagenesis based on the preferable effect of the mutagen on DNA in the site of replication. The spore germination was synchronized by selection of the spores of the definite size and maintenance at a temperature of 0 degrees. The periods of formation of the highest numbers of morphological and auxotrophic mutants were compared with the time of DNA replication.

[Production of active mutants of a new species of rifamycin producer resistant to specific actinophage]. / Poluchenie aktivnykh mutantov novogo vida produtsenta rifamitsina, ustoichivykh k spetsifichnomu aktinofagu

Selection of a phage-stable strain of a new species of the rifamycin-producing organism was carried out. The phage-stable mutants were selected with respect to the virulent phage 2739 isolated from a lysogenic culture of the rifamycin-producing organism. Spontaneous phage-stable mutants formed at a rate of 0.8 per cent. Most of them belonged to the morphological colony type with a decreased activity level. No shifts in variation with respect to the property of the antibiotic production were noted under the action of phage 2739. 62 per cent of the phage-stable variants isolated from the secondary growth colonies after infection with the phage were lysogenic and liberated phage 2739 to the culture fluid. Induction of mutations with MNNG, UV and gamma(Co30) rays increased the frequency of the phage-stable mutanta by 1.5 times. Active phage-resistant mutants stable to the phage because of its adsorption and liberating no phage 2739 into liquid media during its cultivation were selected.