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E G Toropova

Publications and source records attributed to E G Toropova.

At least 19 recordsLinked to original sources
PubMed1989

[Effect of metal cations on the formation of antibiotic and pigment by the mycophilic fungus Hypomyces rosellus 94/77].

Using the method of mathematical planning of experiment the effect of calcium, magnesium, manganese, iron, zinc and copper on synthesis of antibiotic and pigment by mycophilic fungus Hypomyces rosellus has been studied. The ions of Mg2+, Mn2+, Fe2+ have been found to be important for antibiotic and pigment formation by fungus, the ions of Mg2+ and Mn2+ are interchangeable.

Anti-Bacterial Agents↗
PubMed1988

[Selection of the seeding media and the age and quantity of mycelia providing simultaneous biosynthesis of an antibiotic and pigment by the fungus Hypomyces rosellus].

The authors observed maximum simultaneous biosynthesis of antibiotic and pigment in the microphilic fungus with using 48-hour seed mycelium having the specific growth rate of 0.008-0.011 h-1 in an amount of 5-7 per cent (v). The Balling 4 degrees wart and Chapek medium with 1 per cent of soybean flower and 1 per cent of corn steep liquor may be used for growing the seed mycelium. No significant effect of the seed medium composition and seed mycelium age on the pigment production was observed.

Anti-Bacterial Agents↗
PubMed1986

[Properties of the extracellular proteases of Hypomyces rosellus].

A protease complex with high caseinolytic activity capable of hydrolysing various protein substrates was isolated from the culture fluid of Hypomyces rosellus. The preparation is stable at pH 6.0-11.0. The temperature optimum of its activity and stability is 50 degrees C. The protease complex preserves its initial activity at 4 degrees C for a month.

Albumins↗
PubMed1986

[Optimizing the composition of the medium for the biosynthesis of antibiotic, proteases and pigments by the mycophilic fungus Hypomyces rosellus using a mathematical experimental design method].

Regulation of protease and pigment production in Hypomyces rosellus by the medium components was easier than that of antibiotic production. Medium was developed. The activity of exoproteases and pigment with the use of this medium increased up to 385-800 PU/ml and 0.68-0.83 arbitrary units, respectively. The level of the antibiotic biosynthesis was insignificant.

Anti-Bacterial Agents↗
PubMed1983

[Properties of the extracellular proteases of Nocardia fructiferi var. ristomycini].

A complex of proteases was isolated from the culture fluid of Nocardia fructiferi var. ristomycini, strain 76. The complex showed caseinolytic activity and was capable of coagulating milk for 30 minutes. It was stable at a temperature of 50 degrees C and pH 8.0. The maximum level of casein hydrolysis was observed at 37 degrees C and pH 8.0. The protease complex preserved its properties for 3 months at 4 degrees C and for 1 month at room temperature.

Drug Stability↗
PubMed1983

[Several conditions of formation and isolation of violet pigment from culture fluid of Nocardia fructiferi var. ristomycin].

A new water-soluble photochromogenic fluorescent violet pigment with the indicator properties was isolated from the culture fluid of Nocardia fructiferi var. ristomycini, strain 76. By its solubility and mobility in various solvent systems and by the absorption spectrum the new pigment is close but not identical to such a pigment as rubrocyanin. The presence of microelements, i.e. iron and magnesium in the medium was shown to be necessary for production of violet pigment.

Anthocyanins↗
PubMed1982

[Effect of various carbon and nitrogen sources on the biosynthesis of ristomycin, protease and pigments by a culture of Nocardia fructiferi var. ristomycini].

The effect of various sources of carbon and nitrogen on the biosynthesis of ristomycin, protease and pigments by Nocardia fructiferi was studied. It was shown that the carbon sources had the most significant effect on the biosynthesis of the antibiotic. The maximum biosynthetic activity of the Nocardia was observed in the medium containing 1-2 per cent of soybean meal and 2 per cent of glycerol. Under such conditions all the three biologically active substances formed. The contents of ristomycin, protease and pigments amounted to 562-649 microgram/ml, 26-30 PU/ml and 0.45-0.63 conditional units, respectively.

Carbon↗
PubMed1980

[Action of antibiotics on the growth and metabolic processes of streptomycetes and Nocardia].

New experimental data on the effect of novobiocin, ristomycin and nystatin on growth and metabolism of Streptomycetes and Nocardia are presented. The study of the organisms producing other antibiotics showed that they were tens, hundreds and even thousands times more sensitive to the tested biologically active compounds than the organisms producing these compounds. The protein synthesis and antibiotic biosynthesis proved to be most sensitive out of the processes studied. The findings showed that during their evolution the antibiotic-producing organisms have developed definite protective mechanisms which enable them to resist relatively high concentrations of their own metabolites (antibiotics). This ensures them in their struggle for existence.

Dose-Response Relationship, Drug↗
PubMed1980

[Action of novobiocin on the capacity of Nocardia fructiferi var. ristomycini for ristomycin biosynthesis].

The effect of novobiocin in concentrations of 0.05 and 0.2--0.3 microgram/ml on morphological variation of N. fructifer and its capacity for ristomycin production was studied. It was found that the number of colonies with the maximum activity increased under the effect of novobiocin used in a concentration of 0.05 microgram/ml. An increase in the level of novobiocin in the medium up to 0.2--0.3. microgram/ml markedly increased the number of the colonies with low antibiotic productivity.

Dose-Response Relationship, Drug↗
PubMed1976

[Study of the carbohydrate metabolic enzyme activity of Act. noursei].

Activity of aldolase and threosophosphate dehydrogenase, transketolase and phosphogluconate dehydrogenase in Act. noursei, strain 153 and its inactive mutant 149 was studied comparatively. The enzyme activity of the inactive mutant was investigated in the absence of the antibiotic production and under conditions of reduced biosynthesis of nystatin in this strain after addition of the fermentation broth filtrate of the inactive mutant 369 to the medium. The activity of the enzymes of the hexosomonophosphate metabolic pathway in the active strain 153 of Act. noursei was 2-4 times higher than that of the inactive mutant 149. The activity of the enzymes of the hexosomonophosphate metabolic pathways increased and reached the level of the enzyme of the active mutant. The high level of the enzyme activity of the hexosomonophosphate glycolysis pathway is probably one of the necessary conditions for nystatin production.

Carbohydrate Metabolism↗
PubMed1976

[Nystatin biosynthesis by inactive mutants of Act. noursei when cultured together].

Inactive mutants of the nystatin-producing organism Act. noursei were selected. When 2 of them were cultivated together, nystatin biosynthesis was restored. The substance or substances restoring the antibiotic biosynthesis was excreted into the culture broth. It had non-protein nature and was stable on storage. Reduction of the nystatin biosynthetic chain proceeded without changes in the cultivation conditions.

Culture Media↗
PubMed1975

[Study of the fructosediphosphate aldolase and transketolase activity in the nystatin producer, Actinomyces noursei].

Activity of transketolase, an enzyme of the pentose cycle and fructosodiphosphataldolase, an enzyme of glycolisis was studied in the dynamics of development of the nystatin-producing organism and its inactive mutant under various conditions of their cultivation with a purpose of finding relation between the antibiotic production and general metabolism of Act. noursei. The transketolase activity of the organism was 2-4 times higher than that of the inactive mutant. Addition of 8000 Units/ml of nystatin to the medium markedly suppressed (50-100 per cent) the aldolase activity, however it had no effect on the transkelotase activity. Possibly the antibiotic accumulated in the mycelium played the role of a regulator of the activity of the enzymes, directing the metabolites along the hexosomonophosphate pathway of carbohydrate dissimilation.

Aerobiosis↗