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G F Levanova

Publications and source records attributed to G F Levanova.

At least 19 recordsLinked to original sources
PubMed1998

Phenotypic diversity of Pseudoalteromonas citrea from different marine habitats and emendation of the description.

Four strains of marine, aerobic, agar-decomposing bacteria with one polar flagellum and with DNA G + C contents of 38.9-40.2 mol% were isolated from the Far-Eastern mussels Crenomytilus grayanus and Patinopecten yessoensis. These four strains were identified as Pseudoalteromonas; however, they were phenotypically different from species described previously according to carbon compound utilization tests and the BIOLOG identification system. High agar-decomposing activity was found in two strains, in one of which agarase, alpha-galactosidase, pustulanase and laminarinase had been detected. The level of DNA homology of three of the strains was 70-100%. The fourth isolate was genetically less related to the others (67% DNA relatedness) and phenotypically was more distant from other members of this group; however, all four strains were assigned to a single species genotypically. DNA from the strains isolated from mussels showed 40-45% genetic relatedness with the DNA of Alteromonas atlantica, 8-36% with DNA of Pseudoalteromonas haloplanktis subsp. haloplanktis, Pseudoalteromonas haloplanktis subsp. tetraodonis, Pseudoalteromonas undina, Pseudoalteromonas nigrifaciens and Pseudoalteromonasas carrageenovora, 53% with Pseudoalteromonas elyakovii, 32-48% with marine P. nigrifaciens from mussels and 14-16% with Alteromonas macleodii. The DNA-DNA hybridization data revealed that the levels of relatedness between the strains isolated and the type strains of Pseudoalteromonas citrea and Pseudoalteromonas fuliginea described recently were significant (95-85%). These results were confirmed by serological data employing polyclonal antibodies to cell surface antigens. The strains isolated from mussels were identified as P. citrea. The hybridization data showed that the name P. fuliginea Romanenko et al. 1994 should be recognized as a junior subjective synonym of P. citrea Gauthier 1977. A notable phenotypic diversity of P. citrea which might be a reflection of their ecological habitats is discussed.

Animals↗
PubMed1992

[Plasmid analysis of cadmium- and penicillin-resistant strains of staphylococci isolated in maternity hospitals].

The plasmid analysis of a collection of the staphylococci isolated was made in the obstetric hospitals of Nizhny Novgorod and Arzamas in 1986-1989. It revealed the presence of large complex plasmids with a molecular weight of 22 MD carrying the determinants of resistance to penicillins and cadmium and mercury ions in polyresistant strains. Conjugation transfer of the plasmid even between the staphylococci of different species was performed under experimental conditions. It was suggested that occurrence of the strains carrying the complex cadmium-penicillinase plasmid was due to violation of the sanitary or ecological requirements.

Cadmium↗
PubMed1991

[The isolation of Vibrio fluvialis on the territory of the USSR].

For the first time V. fluvialis strains were detected on the territory of the USSR. The taxonomic position of these vibrios was determined by their nucleotide DNA composition (the content of guanine + cytosine was 49.3-51.0 mole%) and the characteristic features of their phenotype. The individual features of the strains consisted in their capacity for agglutination with cholera antisera, groups 01 and Inaba, in diagnostic dilutions in the presence of differences in genomes and phenotypes with cholera vibrios. Molecular hybridization DNA-DNA also gave no confirmation of their relationship to cholera vibrios (23-26% homology). The comparative study of V. fluvialis strains from the USSR and other countries by a broader set of their phenotypical signs confirmed their identity.

DNA, Bacterial↗
PubMed1988

[The degree of DNA homology in enterococci].

Studies carried out by the method of DNA-DNA hybridization have confirmed that Enterococcus faecalis, S. faecium and S. durans are independent species. As revealed in these studies, S. faecalis are homogeneous, genetically related and form an independent, sharply defined species, while S. faecium form a heterogeneous species. Mobile enterococci with yellow pigmentation must not be classified with both S. faecalis and S. faecium.

Base Sequence↗
PubMed1988

[Staphylococcal DNA as a basis for classification].

The genome characterization of the typing strains for all 13 species of the genus Staphylococcus, included into the Approval List of the Names of Bacterial (1980), is presented. The nucleotide composition of DNA (28-33% of GC) did not permit the differentiation between staphylococcal species, but some of the groups of these species could be differentiated by the size of their genome (0.6-1.6 X 10(9) daltons). Differences in the degree of similarity between the nucleotide sequences of the DNA of all species (5-6% of DNA homology) made it possible to suggest raising the genus Staphylococcus to the rank of the family Staphylococcaceae fam. nov. The hypothetical classification scheme of this family is presented for discussion.

Base Sequence↗
PubMed1982

[Complex studies in the surveillance of the environmental Vibrio flora in the city of Gorki and Gorki Province].

The analysis of the results of the comprehensive studies (phenotypic and genotypic properties, the precipitation test with the use of spontaneously agglutinating cultures, the determination of the antigenic structure by immunochemical analysis, etc.) carried out during the sanitary microbiological control of the environmental vibrioflora for the last 5 years are presented. Only the combined use of the above-mentioned methods has allowed to ascertain the taxonomic position of atypical cultures.

Aeromonas↗
PubMed1982

[Nucleotide composition of enterococcal DNA].

A simple method for isolating DNA from enterococci has been developed. This method allows one to extract DNA of good quality in optimal amounts irrespective of the method used for obtaining the culture and the duration of its incubation. Mobile enterococci are sharply differentiated into 3 groups in accordance with their nucleotide composition, the content of GC pairs in DNA being 31.6% in group 1, 35.8-38.0% in group 2, and 40.6-41.5% in group 3.

Base Composition↗
PubMed1981

The possibility of differentiating Vibrio and Aeromonas on the basis of correlation of the nucleotide composition of DNA and the peculiarities of the antigenic structure.

The nucleotide composition of DNA was correlated with the peculiarities of the antigenic structure of vibrios and aeromonades. The authors propose a supplementary test for the differentiation between these microorganisms by the detection of thermolabile "indicator" antigens, most characteristic of cholera vibrios and pathogenic NAG vibrios, in immunoelectrophoresis with diagnostic serum to alcoholic preparation of NAG-vibrio flagellin.

Aeromonas↗
PubMed1980

[Genome characteristics of a new group of microorganisms in the Vibrionaceae family].

A new group of microorganisms isolated from river and sewage water was studied by the method of molecular DNA-DNA hybridization and included into the family Vibrionaceae on account of their phenotypical properties. The genomes of the microorganisms belonging to this group proved to be highly similar (41-92% of homologies), which suggested that they were related on the genus level. The degree of similarity between the nucleotide sequences in the DNA of the bacteria under study and the DNA of other representatives of the family Vibrionaceae (the genera Vibrio, Beneckea, Aeromonas, Plesiomonas) amounting to 10-20% of homology indicates that the group of microorganisms under study forms a separate genus within the family Vibrionaceae.

Base Sequence↗
PubMed1980

[Differentiation of bacteria of the genus Aeromonas from other representatives of the Vibrionaceae family on the basis of their DNA].

By comparing the data on the nucleotide composition of DNA, and the phenotypic characteristics, most of the representatives of the genus Aeromonas were clearly differentiated from NAG vibrios isolated in the process of sanitary control of the environment. At the same time some microorganisms with the Aeromonas phenotype, but having a different DNA structure were detected. The use of the method of molecular DNA hybridization indicated that these bacteria were the taxons analogous to the genus Aeromonas.

Aeromonas↗
PubMed1975

[More precise identification of the systematic position of marine bacteria by the method of DNA-DNA hybridization].

In the present work by the method of molecular DNA hybridization there was shown a low degree of affinity of the standard museum strains of cholera vibrios to the respresentatives of the sea species V. parahaemolyticus and V. alginolyticus, and also halophilic vibrios identified earlier on the basis of phenotypical characteristics of the nucleotide DNA composition as Marinovibrio. The presence of only 20--30% of homology in the DNA successiveness in cholera vibrios and the mentioned sea bacteria pointed to the necessity of exclusion of the latter from the Vibrio genus.

DNA, Bacterial↗