Том 3, № 2 (2011)

During the past two decades, tens of thousands of Russian scientists, including leading researchers in the field of biomedicine, have left Russia to work abroad. Some scientists maintained contact with institutes of the Russian Academy of Sciences (RAS) and the Russian Academy of Medical Sciences (RAMS); however, such interactions were usually initiated by the scientist. Recently, there has been a shift in the pattern of international collaboration; the meeting between the representatives of the National Institute of Health (USA) and the Russian Academy of Sciences, held on April 25-26, 2011, in Moscow, is evidence of this change.

A number of ribosomal proteins in Escherichia coli undergo posttranslational modifications. Six ribosomal proteins are methylated (S11, L3, L11, L7/L12, L16, and L33), three proteins are acetylated (S5, S18, and L7), and protein S12 is methylthiolated. Extra amino acid residues are added to protein S6. C-terminal amino acid residues are partially removed from protein L31. The functional significance of these modifications has remained unclear. These modifications are not vital to the cells, and it is likely that they have regulatory functions. This paper reviews all the known posttranslational modifications of ribosomal proteins in Escherichia coli. Certain enzymes responsible for the modifications and mechanisms of enzymatic reactions are also discussed

Seventeen population groups within the Russian Federation were characterized for the first time using a panel of 15 genetic markers that are used for DNA identification and in forensic medical examinations. The degree of polymorphism and population diversity of microsatellite loci within the Power Plex system (Promega) in Russian populations; the distribution of alleles and genotypes within the populations of six cities and 11 ethnic groups of the Russian Federation; the levels of intra- and interpopulation genetic differentiation of population; genetic relations between populations; and the identification and forensic medical characteristics of the system of markers under study were determined. Significant differences were revealed between the Russian populations and the U.S. reference base that was used recently in the forensic medical examination of the RF. A database of the allelic frequencies of 15 microsatellite loci that are used for DNA identification and forensic medical examination was created; the database has the potential of becoming the reference for performing forensic medical examinations in Russia. The spatial organization of genetic diversity over the panel of the STR markers that are used for DNA identification was revealed. It represents the general regularities of geographical clusterization of human populations over various types of genetic markers. The necessity to take into account a population’s genetic structure during forensic medical examinations and DNA identification of criminal suspects was substantiated.

AICAR is a natural compound, an analogue and precursor of adenosine. As activator of AMP-activated protein kinase (AMPK), AICAR has a broad therapeutic potential, since it normalizes the carbohydrate and lipid metabolism and inhibits the proliferation of tumor cells. The synthesis of AICAR in Bacillus subtilis cells is controlled by the enzymes of purine biosynthesis; their genes constituting purine operon (pur-operon). Reconstruction of purine metabolism in B. subtilis was performed to achieve overproduction of AICAR. For this purpose, the gene purH, which encodes formyltransferase/IMP-cyclohydrolase, an enzyme that controls the conversion of AICAR to IMP, was removed from the B. subtilis genome, ensuring the accumulation of AICAR. An insertion inactivating the gene purR that encodes the negative transcriptional regulator of the purine biosynthesis operon was introduced into the B.subtilis chromosome in order to boost the production of AICAR; the transcription attenuator located in the leader sequence of pur-operon was deleted. Furthermore, the expression integrative vector carrying a strong promoter of the rpsF gene encoding the ribosomal protein S6 was designed. The heterologous Escherichia coli gene purF encoding the first enzyme of the biosynthesis of purines with impaired allosteric regulation, as well as the modified E.coli gene prs responsible for the synthesis of the precursor of purines - phosphoribosyl pyrophosphate (PRPP) - was cloned into this vector under the control of the rpsF gene promoter. The modified purF and prs genes were inserted into the chromosome of the B. subtilis strain. B. subtilis strain obtained by these genetic manipulations accumulates 11-13 g/L of AICAR in the culture fluid.

Periodontitis is a common disease that is considered to be a manifestation of the distortion of the ratio between the normal and conditionally pathogenic microflora of periodontal pockets. In this study, the ratio between the six most important periodontal pathogens and the total microflora of the periodontal pocket in healthy individuals and patients with varying severity of periodontitis was ascertained by quantitative real-time PCR. It was ascertained that the relative content of Porphyromonas gingivalis, Prevotella intermedia, and Tannerella forsythensis (Bacteroides forsythus) persistently develops in the total microflora of the periodontal pocket upon progressing periodontitis; this value is higher than that in the control group by more than two orders of magnitude upon a severe degree of chronic generalized periodontitis.