[Testing of the gas vortex culture stirrer under conditions of short-term microgravity].

Functional testing of the bioreactor for stirring culture in microgravity was performed during the microgravity episodes aboard research airplane Il-76 following the Kepler parabolic flight path. The attempt to produce the gas vortex stirring effect in a given liquid volume was a failure. Nonetheless, the stirrer ventilator is capable to agitate liquid acting as a mechanical stirrer.

[Polymorphisms of DNA repair genes ERCC2 and XRCC1 in populations of Russia].

We have conducted a comparative study of allele frequencies of single nucleotide polymorphisms (SNPs) rs1799793 and rs13181 of the ERCC2 gene as well as rs1799782 and rs25487 of the XRCC1 gene in population samples from European regions of Russia as well as in populations of Izhemsk and Priluzsk Komi and Yakuts. Significant differences in the distribution of polymorphic variants of the ERCC2 gene were demonstrated between populations of Yakuts and populations of Russians and Komi. In case of XRCC1 gene Izhemsk Komi population exhibited dissimilar allele frequencies compared to other populations.

[Detection of intragenomic polymorphism in the LR2 region of human intergenic ribosomal spacer]. / Obnaruzhenie vnutrigenomnogo polimorfizma uchastka LR2 mezhgennogo ribosomnogo speisera cheloveka.

It is a common point of view today that tandem ribosomal genes are subject to concerted evolution, a process that promotes homogeneity among the many copies through the mechanisms of unequal homologous exchange and gene conversion. These mechanisms can lead to opposite results: they can correct and eliminate new variants and they also can promote the spread of new gene variants throughout individual gene clusters among homologous and non homologous chromosomes. A number of experiments performed to decide which of these mechanisms is more important have yielded contradictory answers to this question. In this work we have cloned and partially sequenced 36 PCR-amplified copies of the human rIGS segment 22763-23523 apart from the transcription start point, obtained from the individual genome. This segment is enriched by (G)n and (AG)n clusters and enters into 2kb LR2 element of the human rIGS. Comparative analysis showed that absolutely identical sequences are absent among 36 inserts sequenced. The 26 clones differed only on a number of repeating elements in the paralogous (G)n and (AG)n clusters. The last ten clones differed not only on a number of cluster repeating elements, but contained insertions and deletions of distinct sizes, which do not correspond to the human rIGS polymorphism variants described earlier.