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S M Navashin

Publications and source records attributed to S M Navashin.

At least 127 records · Page 7Linked to original sources
PubMed1979

[Aminoglycoside-3'-phosphotransferase from Actinomyces fradiae. Its isolation, purification and properties].

Aminoglycoside phosphotransferase was isolated from the mycelium of Act. fradiae, the neomycin-producing organism, with paromomycin, neomycin and to a less extent ribostamycin being substrates of aminoglycoside-phosphotransferase. It was purified to homogenous state. The maximum activity of the enzyme preparations was observed at pH 7.7--7.8;KM for neomycin and paromomycin was about 20 micron and KM for ATP was 150 micron. Mg2+ ions were necessary for the enzyme activity. None of the divalent cations tested could replace the magnesium ions in the reaction of phosphorylation catalyzed by the enzyme. High sensitivity to the ionic strength of the buffer was characteristic of the enzyme. It lost about 80 per cent of the initial activity at a concentration of KC1 equal to 1.0 M. The molecular mass of the enzyme from the mycelium of Act. fradiae was determined by the method of gel-filtration through sefadex G-100. It was about 22,000. High stability was characteristic of the enzyme. The fingings indicate that aminoglycoside phosphotransferase from Act. fradiae differs from the described aminoglycoside-3'-phosphotransferases isolated from antibiotic resistant bacteria.

Aminoglycosides↗
PubMed1979

[Pharmacokinetics and biotransformation of rifamycins in the body of experimental animals].

The study on distribution of 14C-rifampicin and 14C-rifamycin S in experimental animals after intramuscular administration of the drugs showed that concentrations of rifampicin in the organs and blood were higher than those of rifamycin S. Biotransformation products of both antibiotics, such as 25-deacetylrifampicin, N-oxide of rifampicin, 3-phormylrifamycin SV, rifamycin SV and others were found in the liver, kidneys, bile and urine. No products of the antibiotic metabolism were found in the blood, lungs and spleen.

Animals↗
PubMed1978

[Rifampicin action on the ultrastructure of E. coli cells].

The ultrastructure of Coli bacteria exposed to rifampicin was studied. Dependence of the level of the ultrastructural changes on the antibiotic concentration and the time of incubation with the antibiotic was shown. After exclusion of the antibiotic from the medium the organism growth with normal ultrastructure was observed.

Dose-Response Relationship, Drug↗
PubMed1978

[Formation of colonies of P-388 leukemic cells in semisolid agar].

Substrain P-388/A2 adapted to cultivation of agar gel in the form of compact colonies was obtained as a result of alternating passages of cells of ascitic mouse leukemia P-388 in the primary semifluid agar culture and in the mouse abdominal cavity. The efficacy of colony formation and the size of the colonies depended on the initial density of the cell suspension. In case of introduction into the agar medium of 100 cells/ml the planting efficacy constituted 20%, and the number of cells in the colony by the 8th--10th days of cultivation reached 13 000.

Animals↗
PubMed1978

[Directed isolation of Micromonospora generic cultures from moist soils and silts].

The data on the study of various soils and substrates for isolation of Micromonospora from them are presented. It was shown that Micromonospora predominated in moist soils and especially in such substrates as silts where their content with respect to the all actinomycetous isolates amounted to 88.9 per cent. In the silts the content of Micromonospora amounted to 66.6--83 per cent, in the sopromely its content was 66 per cent, while in the ordinary non-moist soil its content was from 6 to 11 per cent. Predominance of Micromonospora in silts and moist soils makes its directed search possible.

Asia, Eastern↗
PubMed1977

[Antiviral properties of analogs of distamycin A].

The effect of 9 analogues of distamycin A was studied in a tissue culture with respect to the virus of a smallpox vaccine and classical avian plague. Three analogues of distamycin A (I, VI, VII) were studied in chick embryos with respect to the smallpox and influenza viruses. The analogues were characterized by a loss or decrease of the activity against the smallpox vaccine virus as compared to distamycin A. In contrast to distamycin A analogue VII had an inhibitory effect on influenza infection in chick embryos.

Antiviral Agents↗
PubMed1977

[Development of a method for the quantitative assessment of the microorganism sensitivity to antibiotics by using discs. A study of the patterns of doxycycline diffusion from discs into the nutrient agar].

Doxycycline concentrations provided by the antibiotic diffusion from paper discs into sterile agarized medium and the medium plated with staphylococci and Coli bacteria were studied at different distances from the disc center. Infection of the nutrient medium with the test cultures had no effect on the antibiotic diffusion rate. A linear relation between the logarithm of the antibiotic concentration in the agar and distance from the disc centre were found. Probably it is possible to determine the MIC of the antibiotic with respect to various microorganisms by the value of the radius of the growth inhibition zone around the disc using diagrams expressing such a relation.

Agar↗
PubMed1977

[Antitumor activity of fatty acid derivatives isolated from protozoa].

Water-soluble monoethers of sucrose and fatty acids were obtained from Trypanosoma lewisi and Astasia longa. The maximum tolerated dose of the preparations on their single intraperitoneal administration was more than 25 g/kg. The doses of 10--40 mg/kg were used repeatedly in therapy. Carcinoma 755, Lewis carcinoma, sarcoma 45, sarcoma 37 and sarcoma 180 were sensitive to the preparations. The preparations were inactive against experimental leukemia.

Animals↗
PubMed1977

[Action of rifampicin on the ultrastructure of Staphylococcus cells].

The ultrastructure of Staphylococcus after its contact with rifampicin was studied by the method of electron microscopy. Changes in the submicroscopic structure of the cells depending on the antibiotic dose and incubation time with the drug were shown on solid and liquid media. After removal of the antibiotic from the medium at the stage of demaging the Staphylococcus ultrastructure growth of the cells with normal ultrastructure was observed.

Cell Membrane↗
PubMed1977

[Antibiotics and the macroorganism (the causes and the mechanism of occurrence of side effects].

The main types of side reactions due to antibiotic therapy are described. The antibiotic groups most often being the cause of side reactions are presented. Dependence of the toxic (organotropic) effect of antibiotics on the therapy scheme, age and pathological changes in the mechanism of their excretion is indicated. The biochemical mechanisms of the side and selective effects of antibiotics are discussed.

Animals↗