[Genotypes of rubella viruses circulating in Russia].

The phylogenetic analysis of rubella virus gene E1 in 6 strains isolated in Russia in 1967 - 1997 and in 36 isolates obtained from different countries during the period of 1963 - 1997 was carried out. Most of the genotypes were classified with genotype 1--these were strains from Europe, North America, Japan, China. Strains not included into genotype 1 were found to exhibit accelerated evolution in comparison with strains of genotype 1, but this was only seeming acceleration, as the strains of genotype "non-1" formed 3 sharply defined groups, standing quite apart, whose intragroup divergence was less or equal to that within genotype 1. The genetic distance between these 3 groups and genotype 1 was essentially higher than the intragroup divergence and equal to 6.20 - 8.21%. The data obtained in this study made it possible to regard these groups as separate genotypes. The suggestion was made that five strains isolated in Russia should be classified with genotypes IIB or III in contrast to strains of genotype II from India, China, South Korea, Italy.

[Study of possible biological transformation of kanamycin to amikacin]. / Issledovanie vozmozhnosti biologicheskoi transformatsii kanamitsina v amikatsin.

For transformation of kanamycin A (Km) to amikacin (Ak) with acylating enzymes from B. circulans, a culture producing butirosin (Btn), cellular and acellular conversion systems and methods for chemical and biological identification of Km, Ak and Btn were developed. The level of conversion of Km to Ak in vivo and in vitro did not exceed 2 per cent.

[Selection and physiological study of culture of Bacillus circulans-- producer of butirosin]. / Selektsionnoe i fiziologicheskoe issledovanie kul'tury Bacillus circulans--produtsenta butirozina.

For isolating a highly active variant of the butirosin-producing culture, a strain forming trace amounts of the antibiotic substance was used. Exposure to nitrosomethylbiuret and nitrosoguanidine and the use of selective media containing streptomycin and butirosin resulted in a 30-fold increase in the strain productivity. Thin layer chromatography of the produced antibiotic substance in the solvent system developed by the authors, mass spectrometry and assay of the antimicrobial spectrum in regard to ++gram-positive and ++gram-negative bacteria by using the known aminoglycosidine-inactivating enzymes revealed that the substance was identical to butirosin. Along with the major product, the fermentation broth contained up to 5 per cent of ribostamycin.

[Electrophoretic separation of spores of producers of kanamycin and tylosin]. / Elektroforeticheskoe razdelenie spor produtsentov kanamitsina i tilozina.

The stages of spore development, the most favourable for electrophoretic separation of the spores, were studied in the cultures producing kanamycin and tylosin. The stage of sporulating was shown to be the optimal. The step-by-step procedure for preparing the spores for electrophoresis is described. There were observed distinctions in the fatty acid spectrum of the cells in the cultures grown from electrophoretic fractions of the spores with different antibiotic production capacity.

[Design of hybrid plasmids based on the actinomycete plasmid pSB24.1 and plasmid prBR325 and a study of their stability in the Streptomyces-E. coli system]. / Konstruirovanie gibridnykh plazmid na osnove aktinomitsetnoi plazmidy pSB 24,1, plazmidy pBR325 i izuchenie ikh stabil'nosti v sisteme Streptomyces-E. coli.

Actinomycete plasmid pSB24.1 was cloned on vector of the E. coli pBR325 system. The following bireplicon plasmids were obtained: pSU501 and pSU502 (by XhoI site of pSB24.1 and SalGI site of pBR325), pSU503 (by Bg1II (c) site of pSB24.1 and BamHI site of pBR325) and pSU504 (by Bg1II(b) site of pSB24.1 and BamHI site of pBR325). In the cells of E. coli C600 plasmids pSU501-504 determined phenotype AprCmrTcs and were stable. In the cells of Str. lividans the initial structure pSU501 selected by Ltz+ phenotype was maintained at a frequency of 12.5 per cent. Analysis of the deletion variants of pSU501 isolated from Str. lividans showed that the deletions were induced by both the pBR325 region and the pSB24.1 DNA fragment near XhoI site. The region from SacII(a) site to Bg1II(b) site clockwise in the map of plasmid pSB24.1 was not significant for its replication and maintenance in Str. lividans. There were detected unique sites of pSB24.1 and its derivatives useful for cloning. Possible shortening of plasmid pSB24.1 by 567 kb (the length between the terminator of the open frame reading translation and XhoI site) was revealed.

[Molecular genetic analysis of the determinant of gentamicin resistance in Enterobacter cloned from a clinical strain]. / Molekuliarno-geneticheskii analiz determinanta ustoichivosti k gentamitsinu, klonirovannogo iz klinicheskogo shtamma Enterobacter.

Resistance of clinical strains of Enterobacteriaceae to aminoglycoside antibiotics and in particular to gentamicin was studied. The data on conjugation and plasmid DNA transformation of a clinical strain 10171 of E. cloacae, as well as the data on P1 transduction showed that its gentamicin resistance was due to plasmids. The gentamicin resistance determinant was cloned from the plasmid DNA with the use of the restriction sites of EcoR I, Hind III and Pst I into the vector plasmid pUC 19. Plasmids pAA1, pAA2, pAA3 and pAA4 carrying the gmr determinant were isolated. Their physical maps were constructed. The restriction analysis supplemented by the data on DNA-DNA hybridization was indicative of the identical 2.0 kb sequences in all the plasmids carrying the gmr determinant.

[Effect of mutation changes in RNA-polymerase and transcription termination factor rho on expression of various operons in E. coli]. / Vliianie mutatsionnykh izmenenii RNK-polimerazy i faktora terminatsii transkriptsii rho na vyrazhenie raznykh operonov E. coli.

Six mutations, impairing DNA polymerase of E. coli in combination with the wild type gene for rho factor or ts-mutation rho 15 have been studied in relation to the expression of seven operons having different types of regulation. The expression of genes for glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase is shown to be constitutive and resistant to mutationally altered RNA polymerase and rho factor. The expression of genes for adenine phosphoribosyltransferase and of deo operon is regulated by rho dependent attenuators with attenuation being lifted incomplete medium. Mutation rho 15 decreases the level of enzymes of thr and lac operons independent of mRNA levels of these operons. Mutation rho 15 effect on posttranscriptional level is modified by mutations damaging RNA polymerase. The data obtained suppose RNA polymerase to affect all stages of realization of genetic information, beginning with promoter recognition and RNA synthesis and including the protein synthesis on mRNA.

[Effect of rifampicin and RNA polymerase changing mutation on the spectrum of proteins synthesized in Escherichia coli cells]. / Vliianie rifampitsina i mutatsii, izmeniaiushchei RNK-polimerazy, na sperktr belkov, sinteziruemykh kletkami Escherichia coli.

Rifampicin (30 mkg/ml) drastically changes the spectra of proteins synthesized by E. coli cells. The formation of some polypeptides is stimulated while that of others is inhibited. Thus, the earlier reported rifampicin stimulation of the synthesis of RNA polymerase beta and beta'-polypeptides is not an exception, the formation of some other proteins is being also enhanced by the antibiotic. After infection of UV-irradiated cells by lambda rifd47 transducing phage the viral proteins are less inhibited than the bacterial ones encoded by the phage. The spectra of proteins synthesized are also affected by rpoC1 mutation at non-permissive temperature. The obtained data suggest that rifampicin and rpoC1 mutation change the interaction of RNA polymerase with different promoters and/or regulatory factors.