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Biomedical subjects

G F Levanova

Publications and source records attributed to G F Levanova.

At least 37 records · Page 2Linked to original sources
PubMedDate not supplied

[Industrially produced eubiotics as materials for isolation and study of DNA].

The optimum and available methods for the isolation of DNA from bacteria, used as the basis of the industrial manufacture of eubiotics (colibacterin, lactobacterin, biobactone) have been developed. The proposed approach makes it possible to isolate DNA, suitable for genosystematic studies under laboratory conditions, directly from producer strains.

Bacteriocins↗
PubMedDate not supplied

[Taxonomic analysis of Pseudomonas strains with uncertain taxonomic status].

Pseudomonas strains isolated from soil and rhizosphere and designated as "Pseudomonas rathonis", Pseudomonas sp. B and Pseudomonas sp. C have been characterized by 113 phenotypic properties and studied by methods of molecular-genetic analysis. The 5'-terminal hypervariable 16S rRNA regions, containing from 208 to 344 nucleotides have been amplified and sequenced. The comparative analysis of sequence results gave evidence about phylogenetic relatedness of studied bacteria (98-100% of 16S rRNA sequences identity) to some saprophytic and plant-pathogenic Pseudomonas species. The latter substantially differed from studied strains in phenotypic characteristics. The DNA-DNA hybridization results have shown the low (0-36%) level of chromosomic DNA homology of "Pseudomonas rathonis", Pseudomonas sp. B, Pseudomonas sp. C strains with the type strains of P. fluorescens, P. putida, P. mendocina, P. pseudoalcaligenes. Obtained data give evidence that these strains belong to some novel Pseudomonas species.

Base Sequence↗
PubMedDate not supplied

[Evaluation of the bacteriological safety of wares made from different metals].

The determination of the integral toxicity of a liquid after its contact with different metallic wares could provide a comparative assessment of the hazards of this ware to living organisms. The distilled water and physiological solution exposed to silverware even for a short period of time (15 min) proved to be deleterious to the specially selected bacterial strains differing in their resistance to different chemical substances while aluminum ware was quite harmless to them after their long (4-day) standing of liquids.

Acinetobacter↗
PubMedDate not supplied

[Taxonomic study of Pseudomonas aurantiaca Nakhimovskaya, 1948 and the proposal of a neotype strain of this species].

The type strain of Pseudomonas aurantiaca VKM B-876 (NCIB 10068) was shown to be identical to P. aureofaciens in its biological properties, G + C--content of DNA and chemical nature of produced pigments. Its genome relatedness value with the type strain of P. aureofaciens was found to be 82%. The properties of 36 orange-pigmented fluorescent bacterial strains corresponding with the special description of P. aurantiaca, are presented. Their DNA homology values with other fluorescent species and with the majority of P. fluorescens biotypes ranged from 0 to 49%. At the same time this bacterial group showed a considerable phenotypic similarity and high DNA homology values (90-100%) with the strains of P. fluorescens biotype II (B). The ability to produce a complex of antibiotics, phloroglucinol derivatives, is also their mutual distinctive characteristic. The unification of orange-pigmented microorganisms and the strains of P. fluorescens biotype B under the specific name P. aurantiaca is proposed, regarding the strains of biotype B as the pigmentless variants of this species. The amended description of P. aurantiaca Nakhimovskaya, 1948 is presented. The neotype strain P. aurantiaca VKM B-1524 is proposed.

DNA, Bacterial↗
PubMedDate not supplied

[Molecular DNA-DNA hybridization in Pseudomonas fluorescens and Pseudomonas putida].

Taxonomic analysis was carried out and DNA-DNA homology studied in cultures of subgroups formed by numerical classification of 124 Pseudomonas fluorescens and P. putida strains. The GC content in the DNA of strains belonging to P. fluorescens subgroups varied from 61.2 to 64.5%, and their DNA-DNA homology with the type strain P. fluorescens ATCC 13525 was 24 to 83%. The lowest genome relatedness with the type culture was found in biotype C of P. fluorescens and P. aureofaciens strains. The GC content in the DNA of strains belonging to two subgroups formed by numerical classification of P. putida varied from 63.8 to 65.0%, and the homology of their DNA with the DNA of the type strain of P. fluorescens was 0 to 10% (for strains of the first and second subgroups, respectively).

Base Composition↗
PubMedDate not supplied

[Improvement in the species identification of Lactobacillus by using microculture test systems and data on its genome structure].

18 microanalytical media, used for the construction of a biochemical plate test system permitting the specific identification of bacteria of the genus Lactobacillus, were developed on the basis of data on the metabolic activity of these bacteria and their need of growth factors. As the results of studies made on 78 Lactobacillus strains with the use of traditional microbiological and gene-systematizing methods, the proposed test system was shown to be reliable and specific.

Bacteriological Techniques↗
PubMedDate not supplied

[Approaches to classifying bifidobacteria based on DNA structural data].

A brief historical review of classifications of Bifidobacteria demonstrates the difficulties in this problem, for the present-day classifications are far from being satisfactory. Based on the genotypical heterogeneity of the genus Bifidobacterium, the authors validate the possibility of raising it to the status of the family Bidobacteriaceae fam. nov. The principle of forming new genera within the frames of this hypothetical family, discussed in the paper, originates from the genomic similarity of representatives of some species of this group of microorganisms.

Bifidobacterium↗
PubMedDate not supplied

[Attempt to establish genome similarity between Alcaligenes faecalis and several Gram-negative bacteria using the method of molecular hybridization of DNA to DNA].

The technique of DNA-DNA molecular hybridization was used to demonstrate the absence of genome similarity between Alcaligenes faecalis and gram-negative bacteria belonging to the genera Pseudomonas, Enterobacterium, Comamonas producing alkalis, and vibrions. Some similarity in the polynucleotide sequences was found between the DNA of the reper strain of Alcaligenes faecalis 45 (5--10% of homology) and the DNA of the culture belonging to the Achromobacter genus; therefore, the two genera may belong to one and the same family.

Alcaligenes↗