[Controlled search for the producers of ionophore antibiotics among Streptomycetes]. / Naprablennyi poisk produtsentov antibiotikov-ionoforov iz streptomitsetov.

A procedure was developed for directed screening of cultures producing ionophore antibiotics among streptomycetes. The procedure is based on measuring the membrane potential generated in the presence of the Men+/nH+ = -expchanger-protonophore couple. It provided isolation of cultures producing ionophore antibiotics at the fermentation broth stage. It was possible to use the procedure in screening both electrogenic and nonelectrogenic ionophores and to rapidly differentiate them. 5 cultures producing ionophore antibiotics were detected with this procedure; 3 of them carry out nonelectrogenic transport of the cations. The cation transport in the other two cultures was electrogenic. Cation selectivity of the antibiotics produced by the cultures was determined with the procedure. An antibiotic identical to indanomycin was isolated from the culture fluid of Streptomyces chromogenes.

[Optimization of the nutrient medium composition for the biosynthesis of the antibiotic tobramycin using a mathematical experimental design method]. / Optimizatsiia sostava pitatel'noi sredy dlia biosinteza antibiotika tobramitsina s pomoshch'iu matematicheskogo metoda planirovaniia éksperimenta.

The mathematical design of the experiment was used for optimization of the nutrient medium for biosynthesis of tobramycin by Streptomyces cremeus var. tobramycini. The use of the orthogonal Latin rectangles provided development of the fermentation medium composition and definition of the optimal concentration of its ingredients. The level of tobramycin production on this medium was 2 times higher than that on the initial one.

[Effect of culture parameters on tobramycin biosynthesis]. / Vliianie nekotorykh parametrov kul'tivirovaniia na biosintez tobramitsina.

The effect of temperature, aeration and active acidity of the medium on biosynthesis of tobramycin was studied. The optimal temperature conditions (37 degrees C) were developed. It was shown that biosynthesis of tobramycin depended on the aeration conditions, especially at the beginning of the fermentation process. The initial pH 4.9-6.35 and 6.35-7.1 were found to be optimal for the growth of the tobramycin-producing organism and biosynthesis of the antibiotic, respectively.

[Effect of the inoculum on tobramycin biosynthesis]. / Vliianie posevnogo materiala na biosintez tobramitsina.

The effect of the quality and quantity of the inoculum on the biosynthesis of tobramycin was studied. The medium with corn steep liquor and glycerol was found to be the optimal seed medium for the tobramycin-producing organism. It is required that the fermentation medium be supplemented with 2 per cent of the vegetative inoculum at the stationary growth phase or with an increased amount of the seed material at the exponential growth phase or at the early stage of the culture dying. Subculturing of the inoculum decreases the level of tobramycin production at the fermentation stage: when the culture of the 5th--6th generation is used, the activity of the fermentation broth decreases by 30--50 per cent.

[Stability of the antibiotic formation trait of the tobramycin producer Streptomyces cremeus subsp. tobramycini]. / Izuchenie stabil'nosti produtsenta tobramitsina Streptomyces cremeus subsp. tobramycini po priznaku antibiotikoobrazovaniia.

The stability of the tobramycin-producing organism was studied by the property of the antibiotic production. The organism was stored under conditions of different exposures to light and subculture on slants. The culture was also subjected to long-term storage with various methods. The organism was stable in preserving its antibiotic activity for 1.5 months when stored on the Gauze organic agar No. 2. Subcultures of the organism on this medium provided preservation of the antibiotic activity throughout 4 passages. The culture storage on millet provided preservation of the antibiotic activity for 6 months.

[Effect of several components of the nutrient medium on the biosynthesis of tobramycin]. / Vliianie nekotorykh komponentov pitatel'noi sredy na biosintez tobramitsina.

The optimal concentrations of mineral phosphorus for the growth of the tobramycin-producing organism and for the production of the antibiotic by it in the synthetic medium were determined. Introduction of an additional source of mineral phosphorus into the rich soybean medium resulted in decreased levels of antibiotic production. The stimulating effect of manganese sulfate on the biosynthesis of tobramycin in the rich medium was shown. The stimulating effect of soybean, linseed and palm oils on the production of tobramycin was evident when the fermentation period was longer.

[Kafamycin--a new pyrrol ether antibiotic]. / Kafamitsin--novyi pirroléfirnyi antibiotik.

Cafamycin is a novel polyether antibiotic active against gram-positive bacteria. It was isolated from the culture fluid of Streptomyces sp., an organism producing the anthracycline antibiotic galtamycin. The structure of cafamycin was assessed by spectral analysis: UV, PMR, mass spectroscopy and CD. Physico-chemical and biological properties of the antibiotic are described. Cafamycin was shown to be an analog of indanomycin (X-14547A), a pyrrol ether antibiotic.

[The antibiotic galtamycin. Its fermentation, isolation, physicochemical and biological properties]. / Antibiotik galtamitsin. Fermentatsiia, vydelenie, fizikokhimicheskie i biologicheskie svoistva.

A culture of Streptomyces sp., producing an antibiotic named galtamycin was isolated from a soil sample collected in the Gorno-Altai Autonomous Region. The antibiotic belongs to anthracyclines. Biosynthesis, isolation, physico-chemical and biological properties of the antibiotic are described. The studies showed that galtamycin consisting of a chromophore and three unidentified sugars is a new compound differing from the known anthracyclines except trypanomycin by the absence of the UV absorption maximum at 230-240 nm. Galtamycin differs from trypanomycin by the molecular weight of the chromophore. Galtamycin showed low antitumor activity and was inactive against grampositive and gramnegative organisms and fungi.

[Optimization of the nutrient medium makeup for the biosynthesis of bleomycine antibiotic using a mathematical method of experimental design]. / Optimizatsiia sostava pitatel'noi sredy dlia biosinteza antibiotika bleomitsina s pomoshch'iu matematicheskogo metoda planirovaniia éksperimenta.

The fermentation medium for bleomycin biosynthesis was optimized with the help of a mathematical method for experiment modelling. With the use of the schemes of orthogonal latin squares the optimal concentrations of the sources of nitrogen, carbon and mineral salts were determined and the negative effect of cupric sulphate on the antibiotic biosynthesis was shown. The antibiotic production on the developed medium was 3.7 times higher than that on the initial medium.