[Isolation and study of antibiotic INA-1132 (chlorothricin), produced by actinomycete strain].

Taxonomic properties of strain INA-1132 producing antibiotic INA-1132 are described. The antibiotic showed activity against grampositive bacteria and fungi. The strain was classified as belonging to the genus Streptomyces and by its taxomic characteristics is most close to S. baarnensis. The experiments with the bacterial culture Halobacterium salinarum (previously H. halobium) revealed hypolipidemic activity of the antibiotic, i. e. its ability to inhibit biosynthesis of sterols. Conditions for the production of the antibiotic, methods of its isolation and purification, as well as the results of the chemical structure elucidation are described. By its physicochemical properties the antibiotic is identical to chlorothricin. The structure of antibiotic INA-1132 was ascertained by X-ray analysis. Conformation of the molecule of chlorothricin (antibiotic 1132) was determined for the first time.

[Echinomycin production by Actinomadura sp. INA 654].

An actinomycete strain designated as Actinomadura sp. INA 654 was isolated from a chernozem soil sample in the Voronezh Region by the soil sample treatment with millimetric waves (EHF band). The strain produced an antibiotic complex of 2 components, named A-654-I and A-654-II. Investigation of their physico-chemical properties showed that A-654-I was identical to echinomycin, a heteropeptide lactone of the quinoxaline group with antitumor activity, while A-654-II proved to be likely a new natural compound. Production of echinomycin by a representative of the Actinomadura genus was detected for the first time. Up to now, only representatives of the Streptomyces genus were known to produce echinomycin.

167-A, a new antibiotic produced by a mutant of an inactive wild strain of Amycolata autotrophica.

Two related antibiotics, 167-A and 167-B, were isolated from the fermentation broth of a mutant of an inactive wild strain of Amycolata autotrophica. Antibiotic 167-B was found to be cervinomycin A2; antibiotic 167-A is a new representative of the same group and has the structure of 18-O-demethyl cervinomycin A2.

[Antibiotic production by inactive cultures of actinomycetes after treatment with ethidium bromide]. / Obrazovanie antibiotikov neaktivnymi kul'turami aktinomitsetov posle obrabotki étidii bromidom.

Inactive strains of actinomycetes isolated from natural sources were treated with ethidium bromide, an intercalating agent. After the treatment the cultures formed active variants at a frequency of more than 0.1 per cent which was rather high. 41 out of 93 cultures formed variants active against gram-positive bacteria. The majority of the active variants synthesized antibiotics only on agarized media. Daunorubicin was also used as an intercalating agent and shown to induce at a high frequency the formation of active variants with the same antibacterial spectrum as the variants induced by ethidium bromide. Induction of antibiotic production by the intercalating agents in the inactive strains of actinomycetes was likely due to the activation of the silent genes responsible for the biosynthesis of secondary metabolites.

[Antibiotics formed by Actinomadura fulvescens]. / Antibiotiki, obrazuemye Actinomadura fulvescens.

Novel antibiotics with in vitro activity against gram-positive bacteria were isolated from Actinomadura fulvescens INA 3321 and INA 3852. Conditions for biosynthesis and isolation of antibiotics 3321 and 3852, as well as their physicochemical and biological properties were studied. Chromatographic analysis of the antibiotics revealed that each of them contained two biologically active components. The components were separated with preparative chromatography. Physicochemical properties of the components showed that antibiotics 3321 and 3852 were similar. UV and IR spectroscopy suggested that antibiotics 3321 and 3852 were original compounds not described earlier.

[Induction of antibiotic production in inactive cultures of actinomycetes. Monensin production by a mutant strain 2608 EB-1]. / Induktsiia obrazovaniia antibiotikov neaktivnymi kul'turami aktinomitsetov. Obrazovanie monenzina mutantnym shtammom 2608 EB-1.

An actinomycete strain designated as 2608 was isolated from a soil sample. When cultivated on various solid and liquid media, the strain was inactive. The strain exposure to ethidium bromide resulted in formation of a mutant producing an antibiotic active against some gram-positive bacteria. The property of the antibiotic production proved to be stable. The antibiotic was identified by IR, NMR and mass spectroscopy as monensin. Strain 2608 producing monensin differs from the described monensin-producing culture Streptomyces cinnamonensis ATCC 15413 and is a new culture producing monensin.

[Induction of antibiotic formation by inactive cultures of actinomycetes. A mutant strain of Streptomyces helvaticus, a new producer of bruneomycin]. / Induktsiia obrazovaniia antibiotikov neaktivnymi kul'turami aktinomitsetov. Mutantnyi shtamm Streptomyces helvaticus-- novyi produtsent bruneomitsina.

After exposure of an inactive actinomycete to ethidium bromide a stable mutant producing an antibiotic on a solid medium was isolated. The exposure to methylnitrosoguanidine provided the isolation of a more productive variant synthesizing the antibiotic in a liquid medium. By UV, IR, NMR and mass spectroscopy the antibiotic was identified as bruneomycin (streptonigrin). The taxonomic investigation of the culture showed that it belongs to Streptomyces helvaticus which is a new culture producing bruneomycin (streptonigrin). Previously it did not synthesize the antibiotic.

[Actinomadura species as antibiotic producers]. / Vidy roda Actinomadura kak produtsenty antibiotikov.

Screening of antibiotic-producing cultures among Actinomadura showed that definite species mainly produced antibiotics of the same groups. Thus, carminomycins were produced by all the 4 studied strains of A. carminata, maduramycins were produced by 3 strains of A. rubra, prodigiozines were produced by 3 strains of A. madurae and luzopeptines were produced by 6 strains of A. recticatena. Supposedly, new antibiotics with original spectral characteristics were isolated from 2 strains of A. fulvescens. There was a clear-cut relation of the number of the active strains and their antibiotic productivity in definite media to their species. The liquid nutrient media, such as yeast-sucrose, soya-glucose and soya-glucose with cobalt chloride proved to be the most efficient in the primary screening of antibiotic-producing cultures.

[Production of griseoviridin and etamycin by the new culture, Streptomyces albolongus]. / Obrazovanie grizeoviridina i étamitsina novym produtsentom Streptomyces albolongus.

An actinomycete strain designated as 4297 was isolated from a soil sample collected near Moscow. The strain produced a complex of two antibiotics. One of them had a broad antibacterial spectrum and, in terms of its physicochemical properties and X-ray structural evidence, was identified with griseoviridin. The other was active against gram-positive bacteria and, by its chromatographic comparison with an authentic sample, mass spectroscopic determination of the molecular weight and UV spectra, was identified with etamycin. The strain 4297 differed from the described cultures producing griseoviridin and etamycin. By the taxonomic features it was classified as belonging to Streptomyces albolongus.

[Formation of a new polyene antibiotic octamycin by a culture of Actinoplanes ianthinogenes subsp. octamycini]. / Obrazovanie novogo polienovogo antibiotika oktamitsina kul'turoi Actinoplanes ianthinogenes subsp. octamycini.

A culture of Actinoplanes ianthinogenes subsp. octamycini producing a polyenic antibiotic with the UV spectrum characteristic of octaens was isolated. Optimal conditions for biosynthesis of the antibiotic were developed and an active variant 4041-6 producing 2 mg of octamycin per 100 ml of the medium was selected. A procedure for recovery of the antibiotic with the use of Sefadex LH-20 was used. Certain physicochemical characteristics of octamycin were defined. The data on the UV and IR spectra suggested the presence of an alkyl substituent in the octamycin chromophore. The antibiotic showed antitumor activity, sufficient activity against gram-positive bacteria and low activity against fungi and yeasts.

[Formation of a streptothricin-group antibiotic by a Streptomyces glaucus 1136 culture]. / Obazovanie antibiotika iz gruppy streptotritsinov kul'turoi Streptomyces glaucus 1136.

In screening of new antibiotics a streptomycete (strain 1136) was isolated from a soil sample of Armenia. It showed no antagonistic properties in streek cultures on agarized media. When grown under submerged conditions strain 1136 produced an antibiotic active against grampositive and gramnegative bacteria. By its cultural and morphological properties strain 1136 was classified as Streptomyces glaucus Agre et Preobrazhenskaya, 1983. Microbiological and chemical investigation of the antibiotic produced by strain provided its identification at the early stages of the investigation as an antibiotic of the streptothricin group. Up to now no organisms producing streptothricin antibiotics were detected among streptomycetes of the Azureus section including strain 1136.