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Biomedical subjects

V A Tsyganov

Publications and source records attributed to V A Tsyganov.

At least 19 recordsLinked to original sources
PubMed1993

[Colorimetric determination of Krebs Cycle dehydrogenases in mycelium of Actinomycetes (Streptomyces levoris)].

A new procedure for colorimetric determination of the dehydrogenase activity in the mycelium of Streptomyces levoris was developed. The procedure is more precise, universal and adaptive. The novelty of the procedure is in the switching of the respiration chain to ascorbic acid that excludes the use of the respiration chain inhibitors. The adaptivity refers to the adjusting of the reaction to a particular strain by the reaction time and mycelium concentration in the reaction mixture. The procedure is technologically advantageous and handy. It provides simultaneous assay of a large number of samples of different type dehydrogenases.

Adaptation, Physiological↗
PubMed1989

[Determining the conditions for stimulation of levorin biosynthesis in the presence of succinic acid].

Conditions promoting the stimulating effect of succinic acid on biosynthesis of levorin were determined. The optimal concentration of succinate was shown to be equal to 0.05-0.3 per cent and the best time for the addition was before inoculation. The most pronounced stimulating effect was observed when the initial pH value of the fermentation medium was equal to 7.0. The important role of ammonium nitrogen in manifestation of the succinic acid stimulating effect on biosynthesis of levorin was suggested.

Anti-Bacterial Agents↗
PubMed1984

[Action of the products of the vital activity of yeastlike fungi on the biosynthesis of levorin, levoristatin and fatty acids by a Streptomyces levoris culture].

The data on the effect of the products of vital activity of Candida tropicalis, a yeast-like fungus, on the biosynthesis of levorin, levoristatin and fatty acids by Streptomyces levoris are presented. It was shown that the effect of the biostimulators was not specific with respect to production of levorin, since in the presence of the products of vital activity of C. tropicalis an increase in the synthesis of levoristatin and fatty acids was also observed. The qualitative and quantitative composition of the fatty acids of the mycelium of S. levoris was studied. Interrelation between the biosynthesis of levorin and synthesis of unsaturated fatty acids and branched chain fatty acids was noted.

Antifungal Agents↗
PubMed1983

[Biosynthesis of levorin and activity of several enzyme systems of Streptomyces levoris depending on culture conditions].

The regularities of changes in the main oxidation-reduction enzymes of the tricarboxylic acid cycle (TAC) and the pentose cycle were studied under different cultivation conditions: with the use of the control soybean-corn-hydrol medium and the medium with addition of a biostimulant produced by C. tropicalis. It was shown that the activity levels of the dehydrogenase systems of the TAC and the pentose cycle of S. levoris grown in the presence of the biostimulant were higher. The increase in the production levels of levorin due to addition of the biostimulant was connected with the activity of the systems responsible for regeneration of NADP.H2.

Antifungal Agents↗
PubMed1983

[Effect of a biostimulant formed by yeastlike fungi on the dynamics of the accumulation of CoA, biotin and levorin in the process of growth of S. levoris].

Regularities of the effect of a biostimulator produced by years-like fungi on accumulation of CoA, biotin and levorin in a developing culture of S. levoris were studied. It was shown that addition of the biostimulator to the fermentation medium resulted in increased accumulation of CoA and biotin in the mycelium of the levorin-producing culture within the first 48 hours of the growth and in their more intensive consumption at the final stages of the fermentation process. The rate of the levorin synthesis in the medium with the biostimulator markedly exceeded that in the control.

Antifungal Agents↗
PubMed1982

[Role of p-aminobenzoic acid in levorin biosynthesis].

The effect of p-aminobenzoic acid on the biosynthesis of levorin was studied. It was shown that in the presence of exogenic p-aminobenzoic acid the antibiotic activity increased by 11 per cent. The acid added was transformed into p-aminoacetophenone which was partially used for levorin synthesis and partially accumulated in the mycelium in a free state. In this case the synthesis of levorin was limited by the metabolites forming the macrolide ring. When the precursors of the macrolide ring and the aromatic group were simultaneously added to the medium, the content of free p-aminoacetophenone in the mycelium decreased while the antibiotic activity increased by 25 per cent.

4-Aminobenzoic Acid↗
PubMed1981

[Hydrolase activity characteristics of actinomycetes during antibiotic biosynthesis].

The activity of the main extracellular hydrolytic enzymes, such as protease, nuclease and amylase was studied in the process of the development of the actinomycetes producing streptomycin, novobiocin, levorin and oleandomycin. It was found that the enzymatic activity significantly changed during the development of the cultures depending on their individual properties. Comparative study of the enzymatic activity of the streptomycin-producing organisms differing in the antibiotic production levels and the use of special nutrient media providing the increased biosynthesis of DNAases allowed a definite relationship to be disclosed between the activity level of extracellular hydrolases and antibiotic production.

Anti-Bacterial Agents↗
PubMed1981

[Determination of p-aminoacetophenone and changes in its levels in a levorin producer depending on culture conditions].

A method for spectrophotometric determination of p-aminoacetophenone (p-AAP) in the mycelium and fermentation broth filtrates of organisms producing polyenic macrolide antibiotics is described. The level of p-AAP accumulation was studied as applicable to the biosynthesis of levorin, a polyenic antibiotic of the heptaen series. The levels of p-AAP under usual conditions of the levorin-producing organism cultivation and under conditions of its stimulation with the products of the vital activity of yeast-like fungi were compared. Higher levels of p-AAP in the cultures grown with stimulation of the antibiotic biosynthesis were noted. Inadequacy of the correlation between production of levorin and p-AAP is discussed.

Acetophenones↗
PubMed1981

[Isolation and properties of a biostimulator formed by yeast-like fungi and its effect on levorin biosynthesis].

Experiments on isolation of active substances or biostimulators from the culture fluids of yeast-like fungi of Candida (C. tropicalis, strain 159) were performed. Addition of the biostimulators to the fermentation medium for cultivation of the levorin-producing actinomycete provided the same levels of the antibiotic synthesis as mixed cultivation of the actinomycete and C. tropicalis. The biostimulators were found to be thermostable and stable within a wide pH range (2.0--14.0). They are low-molecular compounds of the organic nature.

Antifungal Agents↗
PubMed1980

[Characteristics of the formation of substances by various microorganisms that stimulate levorin biosynthesis].

Production specific properties of substances stimulating levorin biosynthesis by various microorganisms were studied. It was noted that substances activating the biosynthesis of levorin were produced by various species of yeast-like fungi. Filtrates of the fermentation broths of bacteria, yeasts or filamentous fungi did not contain substances increasing the antibiotic synthesis. Filtrates of the fermentation broth of yeast-like fungi increased also the synthesis of polyenic antibiotics, such as mycoheptin and amphotericin and suppressed production of nystatin.

Antifungal Agents↗
PubMed1979

[Effect of the products of the vital activity of yeast-like fungi on levorin synthesis].

The effect on levorin synthesis of the cells and fermentation broth filtrates of Candida tropicalis after their cultivation in the fermentation medium was studied. It was found that the yeast-like fungi belonging to Candida excreted during their development some products capable of stimulating the synthesis of levorin by 40--60 per cent. When the actinomycete producing levorin was grown on the medium containing 80 per cent of the filtrate the level of levorin synthesis was the same as that observed with mixed cultivation of the actinomycete and C. tropicalis. The study on the conditions providing accumulation of the stimulating substances showed the following: production of the stimulating substances started during the first hours of the yeast growth and reached its maximum by the 48th hour, these substances being consumed by the actinomycete during the fermentation process. Aeration is required for production of the stimulating substances but its high levels are not necessary.

Aerobiosis↗
PubMed1976

[New antibiotic, parvulomycin, produced by a culture of Actinomyces parvullus var. chromogenes var. nov].

Actinomycete LIA-O784 was isolated from a soil sample. By its morphological and cultural properties the isolate was close to Act. parvullus but differed from it in synthesis of melanoid pygment, thyrosinase, hydrogen sulphide and pronounced antifungal activity. The actinomycete was classified as a new variant and designated as Actinomyces parvullus var. chromogenes var. nov. The culture produced a new polyglycoside antibiotic named parvulomycin. The physico-chemical characteristics of the antibiotic is presented.

Aminoglycosides↗
PubMed1975

[New tetraene antibiotic, abkhazomycin].

The cultures of Act. L10-0740 and L10-0772 were isolated from a soil sample. By their morphological and cultural features they were close to Act. badiocolor and differed from the latter by their antibiotic properties. Because of this they were classified as a new variant of Act. badiocolor var. abhasus var. nov. The cultures produced a new tetraen antibiotic, named abkhazomycin. Its physico-chemical properties are presented.

Actinomyces↗
PubMed1975

[New heptaene antibiotic, flavomycin, formed by Act. flavus var. geptinicus var. nov].

An actinomycetous culture LIA-0734 was isolated from a soil sample. By its morphologo-cultural properties it was close to Act. flavus and differed from the latter in the sporophores, colour of the substrate mycelium on synthetic media amd markedly pronounced antagonism with respect to yeasts and yeast-like fungi. The culture was classified as Act. flavus var. geptinicus var. nov. The actinomycete produced new aromatic heptaens: flavomycins A and B. Their physico-chemical and biological characteristics and singularity are presented.

Animals↗
PubMed1975

[Comparative characteristics of some actnomycetes, producers of antifungal antibiotics related to chondamycin].

Three actinomycetous strains designated as LIA-0773, LIA-0783 and LIA-0780 were isolated from various soil samples. The cultures actively inhibited the growth of Trichophyton gipseum and produced a non-polyenic antibiotic of the chondamycin type. The strains were identified with Act. griseochromogenes Fukunaga et. al., 1955. The cultures differed within the species by some morphological, cultural, physiological and antibiotic properties, as well as by the component composition of the antibiotic produced. Thus, strain LIA-0773 had larger spiral sporophores, satisfactorily hydrolized starch and inverted sucrose. The strain inhibited the growth of not only the fungi but also grampositive bacteria and mycobacteria and produced an antibiotic composed of 6 components. Strain LIA-0780 had small sporophores with close spirals and low amilolytic activity. It inhibited only the growth of the fungi and produced a monocomponent antibiotic. Strain LIA-0783 was intermediate. By its biological properties it was closer to strain LIA-0780. The antibiotic produced by it consisted of 6 components, while by its physico-chemical properties the antibiotic was close to that produced by strain LIA-0780. All the 3 actinomycetous cultures were considered as different variants of Act. griseochromogenes Fukunaga et al., 1955.

Actinomycetales↗
PubMed1975

[Actinomyces fulvoviolaceus ver. achromogenes var. nov., a producer of the new heptaene complex, fulvomycin].

An actinomycetous culture designated as LIA-0721 was isolated from a soil sample. It was close to Act. fulvoviolaceus by its morphologo-cultural features and differed from it in production of melanoid pigments and the spectrum of carbohydrate assimilation. This justified its classification as Act. fulvoviolaceus var. achromogenes var. nov. The culture produced new aromatic heptaens, i. e. fulvomycins A, B and C. Their physico- chemical and biological characteristics are presented.

Anti-Bacterial Agents↗