Биология

We performed a molecular genetic analysis of Yersinia pestis strains isolated in the Ural-Embensky desert natural plague focus area in the twentieth century. We studied 24 strains of Y. pestis isolated on this territory since 1945 to1991, as well as 21 strains of Y. pestis from adjacent territories. All of the strains studied from the Ural-Embensky natural focus of plague belonged to the highly virulent and epidemically signifi cant medieval biovar of the main subspecies Y. pestis.

The bacteria Azospirillum brasilense, used as biofertilizers, have a signifi cant positive eff ect on the growth and development of plants. The genome of the strain A. brasilense Sp7 is represented by a chromosome and numerous plasmids with molecular weight of 90, 115, and over 300 MDa. Genomic rearrangements that cause changes in the “plasmid profi le” can contribute to the formation of subpopulations or phenotypic variants in a bacterial population. There is little data on the role of such rearrangements in the adaptation of A.

We studied effects of gonadectomy on nitric oxide content in blood in normotensive and hypertensive females and males at rest and stress situation. We revealed the stronger estrogens but not androgens in regulation of basal and stressed secretion of nitric oxide under differ­ ent physiological conditions (rest, stress, arterial hypertension) that may be one of possible mechanism responsible for higher cardiovas­ cular resistance to stress-induced damages in female compared with male.

In this article some results of stock phytomass and primary produc­ tion linden forests of nation park «Chvalynskiy» are presented.

The influence of syntetical compound with antioxidative activity on increaseing of vitality gram-positive and gram-negative microorgan­ isms under stressful action of antibiotical factors was shown.

It is shown that the plant A. dioica populations in the Saratov re­ gion, i.e. in the south-eastern border area of the species, are repro­ duced by seeds exclusively through amfimixis, while the north (in the Penza region), i.e. closer to the central part of the area - through an facultative apomixis.

Based on literature review and own investigations a grow photoregu­ lation problem of wheat seedlings was analyzed. Was show, that some photoregulation systems of wheat embryo have tuned in certain level of light signal. Was proposed the important role of lightenviron­ ment in a period of seeds embryogenesis for wheat germination.

Peculiarities of the linkage between specific birds and mammals density anomalies and entropy of river basins landscapes were investigated. Using mapping methods it has been found that positiv anomalies are concentrated in slopes of Volga-Don, Tereshka-Sura and Tereshka-Tersa watersheds and Medveditsa river valley; the negative ones are connected with agrocenosises of Chardym, Kurdum fnd Shiroky Karamysh rivers valleys.

The results of immunochemical analysis of 63 strains of associative rhizobakteria genus Azospirillum presented in this paper. Significant heterogeneity of O-antigens of strains of A. lipoferum and A. brasi­ lense have been demonstrated, as well as the high similarity of the antigenic properties of LPS strains of A. irakense. Serologically prov­ ed isolated strain A. amazonense. High conservatism of major protein antigens of these bacteria have been showed.