Biomedical subjects

M V Nefelova

Publications and source records attributed to M V Nefelova.

At least 37 records · Page 2Linked to original sources

PubMed1978

[Polymyxin B biosynthesis and tricarboxylic acid cycle enzymatic activity].

Activity of pyruvate dehydrogenase (PDG), isocitrate dehydrogenase, alpha-ketoglutarate dehydrogenase, succinate dehydrogenase and malate dehydrogenase was found in the extracts of the cells of Bac. polymyxa 153, an organism producing polymyxin B. Dependence of the activity of the above enzymes on the carbon source in the medium, aeration conditions, strain features and culture age was shown. A low level of polymyxin B biosynthesis was observed at high activity of PDG and dehydrogenases of the tricarbonic acid cycle. Increased antibiotic production was recorded against the background of decreases values of the above enzyme activities.

Bacillus↗

PubMed1978

[Effect of organic acids on the biosynthesis of macrotetralide antibiotics by an Actinomyces chrysomallus var. carotenoides strain].

The biosynthesis of macrotetrolides by Actinomyces chrysomalus var. carotenoides was stimulated by acetic, succinic, propionic, oxalic, malic, tartaric, citric, pyruvic, alpha-ketoglutaric and fumaric acids. Incorporation of 14C-acetate into the molecule of the antibiotic and the data on dependence of the stimulating effect upon the quantitative ratio and time of the organic acid addition were indicative of the role of acetic, succinic and propionic acids as precursors of macrotetrolides. The other organic acids increased the biosynthesis of macrotetolides when added to the culture within wide time ranges of the culture development and prolonged the period of the mycelium productive state.

Acids↗

PubMed1978

[Biological properties of the modified actinomycins synthesized by the aurantin producer].

The effect of 2 new modified actinomycins was studied. Actinomycin AuGl had the residue of sarcozin replaced by glycine and actinomycin AuNv had 1 residue of norvaline. It was shown that the new actinomycins had a similar to the actinomycin type effect on the microbial and animal cells. Still, higher concentrations of the antibiotics were required. In concentrations equal to those of actinomycins the new antibiotics were less effective with respect to the bacteriostatic action, suppression of the RNA synthesis and mitotic division of the ascitic hepatoma 22A cells.

Amino Acids↗

PubMed1976

[Effect of inorganic phosphorus on the biosynthesis of polymyxin B].

A synthetic medium containing optimal levels of the sources of carbon, nitrogen and inorganic phosphorus and providing satisfactory yields of polymyxin B was developed for 2 strains of Bac. polymyxa 933 and VK-153. The consumption of phosphorus in the medium by the strains and the antibiotic biosynthesis levels depended on the form of phosphorus added to the medium. Optimal biosynthesis of polymyxin B was observed at lower concentration levels of soluble soluble phosphorus in the medium than the bacterial growth.

Bacillus↗

PubMed1974