Genetic analysis of the microevolutionary processes in cattle populations (the example of the B locus of blood groups)

Dynamics of allele frequencies for the B-locus of blood groups in cattle populations and of a number of phenotype indexes in these animals was studied. It is determined that natural stabilizing selection and prezygotic selection, leading to a change in genetic structure, act in every population. The role of sires' influence on this process is insignificant.     

Genetic polymorphism of transferrins in Bovinae

Variability of transferrins in Bovinae is controlled by two loci: Tf (the locus of structural transferrin gene) and T (the locus of a gene responsible for protein modification). Originally, the ancestors of Bovinae, like the other ruminants, had the R type of transferrin (T-/T- genotype, inactive T gene). Later on, the T gene activation occurred and the B type appeared (T+/T-, T+/T+ genotypes). The subsequent evolution of Bovinae was accompanied by almost complete fixation of T+ allele. In one of the Bovinae representatives (Bos taurus L.) the frequency of T- allele remained at the level of approx 0.1. A hypothesis is proposed which explains the change of the transferrin type in Bovinae by imitation of multiple allelic forms of this protein present in Tf heterozygotes, by supplementary modificatory multiple transferrin forms arising on activation of the minor gene (T+). This process is assumed to involve the reduction of Tf locus variability. Since this hypothesis proceeds from the assumption of TF heterozygote advantage, the question is considered, whether this assumption is compatible with high polymorphism of Tf locus which significantly exceeds that for other loci.     

Effect of various amino acids and ammonium salts in a synthetic culture media on the cholera enterotoxin production

The influence of amino acids and ammonium salts on the production of cholera enterotoxin (CT) by 3 Vibrio cholerae strains of different biovars and serogroups was evaluated. As revealed in this study, toxin formation in each of the strains was quantitatively and qualitatively determined by their individual sets of amino acids. The amino acid compositions ensuring the maximum production of CT by the V. cholerae strains under study were formed. The use of ammonium salts as the only source of nitrogen in the composition of a synthetic nutrient medium for the accumulation of CT was shown to be inexpedient.     

Comparisons of cerebral circulation parameters in schoolchildren living in the Far East and European North

Transcranial Doppler sonography and impedansometry was used to study cerebral circulation in students aged from 7 to 17 living in the North in the "absolute discomfort" area (Magadan region. 62 degrees North, 158 degrees East, n = 167) and "discomfort" area (Arkhangelsk region, 61 degrees North, 41 degrees East, n = 52). New data were obtained about both blood flow parameters in main cerebral arteries, vessels tone and vasomotor reactivity as well as differences between these indices in children from the two northern areas. The results reveal that arterial blood flow velocity (BFV) in cerebral arteries is faster in Koryaks and Evens who are the children of the native population compared to BFV in the children born in the North whose parents represent newcomers. A tendency exists in the form of vascular tone rising in the living in the North students. This tendency is more expressed in children and adolescents from Magadan region which is distinguished from Arkhangelsk region by more severe climate. The indices that characterize individual alterations of cerebral circulation under hypoxic-cold factors as well as population peculiarities related to "polar adaptive type of metabolism" forming are discussed.     

EEG correlates of geno-phenotypical features of the brain development in children of the native and newcomers' population of the Russian North-East

Traditional and original methods of EEG analysis were used to study the brain electrical activity maturation in 156 children and adolescents from 7 to 17 years old who represented the native (Koryaks and Evenks) and newcomers' populations living in severe climatic and geographic conditions of the Russian North-East. New data revealing age-, sex- and ethnic-related features in quantitative EEG parameters are presented. Markers are obtained that characterize alterations in the structure of interaction between different EEG rhythms. The results demonstrate age-dependent transformation of this structure separated in time for both different cortical areas and different EEG frequency bands. These alterations show time lag from 2 to 3 years in children of native population compared to the newcomers. The revealed differences are assumed to reflect geno-phenotypical features of morpho-functional CNS development in children of the native and newcomers' population that depend on strong adaptation tension for extreme environmental conditions.     

Genotyping of <Emphasis Type="Italic">Triticum</Emphasis> ssp. Hexaploid Species Samples with ISSR-Markers

The genetic improvement of soft wheat (Triticum aestivum L.) and other hexaploid wheat species (T. spelta, T. spherococcum, T. petropavlovskyi, and T. compactum) is important. This can be done by transferring genes of interest (resistance to biotic and abiotic factors). For this purpose, phylogenetic connections of the studied genotypes should be investigated. This problem can be solved by using a multilocus system based on ISSR markers. The marker system is highly polymorphic and convenient for analysis. The study presents the results of a comparison of 20 different hexaploid wheat genotypes based on ISSR markers. In addition, the level of polymorphism was determined and a dendrogram reflecting the phylogenetic connections between the studied genotypes was constructed. It was shown that the species located next to each other according to the systematics turned out to be more remote after the ISSR-marker analysis, and, vice versa, the species that were systematically more distant showed a higher level of kinship.     

Cortical-subcortical interactions and the brain functional state regulation under acute hypoxia in man

Regulation mechanisms of the brain functional state (FS) were studied in man during acute hypoxic conditions (inhalation of 8% O2 hypoxic air for 15-25 minutes). Changes in balance of the brain regulatory structures activities caused by hypoxia determine FS dynamics that is reflected in the reorganization of the EEG spatial interrelations (by data of factor and cluster analysis of EEG cross-correlation matrices), as well as translocation of intracerebral position of electrical equivalent dipole sources (EEDS) coupled with EEDS density rising in medial and basal regions of the cerebral hemisphere temporal lobes (by EEDS-tomography data). Alterations of the cortical-sub-cortical interactions show a decline in the brain activating system tone, a decrease in the neocortical inhibitory control of subcortical processes, and activation of structures of limbic and hypothalamic regions. Switching of integrative regulatory control mechanism from "cortical-thalamic" system level to "limbic-dyencephalic" one could ensure both removal of powerful unspecific components of hypoxic stress and a greater stability of essential physiological parameters of the main vital functions regulation during oxygen deficiency accumulation.