[Effect of UV-radiation and drying on bacterium diversity in soil].

It has been shown that after DNA-injuring factors (UV irradiation or drying) action on soil one could observe the decrease of the total quantity of bacteria and the number of species, i.e., the decrease of microbe diversity. At the same time not numerous species were found in soils after their action. Thus the drying or UV-irradiation makes it possible to estimate more completely the microbe diversity in soils as well as to find resistant bacteria. It has been established that the strain Methylobacterium extorquens, M. mesophilicum, Bacillus subtilis, B. cereus, which were isolated after UV irradiation or drying of oil samples, were characterized by high resistance to gamma-irradiation (LD99.99--5-10 kGr). Bacteria (representatives of Pseudomonas genus) sensitive to drying or UV-irradiation were also sensitive to ionizing radiation (LD99.99--0.09 kGr). Nocardieforms and representatives of Myxococcus occupied intermediate position between representatives of genera Methylobacterium and Pseudomonas as to resistance to the above-mentioned stress agents.