[A new regulatory function of the A-factor--stimulation of the streptomyces spore germination].

Spore germination in streptomycetes was shown to be stimulated by exogenously added A-factor. Agar medium either containing or not containing A-factor was inoculated with spore suspensions of three strains differing in their ability to produce regulators of the A-factor group: Streptomyces griseus 773, which produces A-factor and two its lower homologs, S. coelicolor A3(2), which forms six AcL-factors (A-factor analogues), and S.

[A-Factor as a selective agent for isolation of the soil Gram-negative bacterium strain--the producent of an antibacterial antibiotic].

It was shown the stimulating role of A-factor on soil prokaryotes growth. Soil sample culturing on agar medium, containing A-factor, resulted in the colony forming units (CFU) increasing in comparison with culturing on the medium without this regulator. Gram-negative bacteria were the reason of CFU increasing; previously the effect of A-factor on bacteria of this group was not shown.

[Antimicrobial activity of Laetiporus sulphureus strains grown in submerged culture].

Cultural conditions for growth and fruit body formation were elaborated to four strains of Laetiporus sulphureus isolated from nature. All strains demonstrated antimicrobial activity against a wide spectrum of gram-positive and gram-negative bacteria during agar and submerged cultivation including methicillin-resistant strain of Staphylococcus aureus (MRSA) and glycopeptide-resistant strain of Leuconostoc mesenteroides. Antifungal activity was not found.

[Increase in eremomycin production by regeneration and UV-irradiation of Amycolatopsis orientalis subsp. eremomycini protoplasts].

Protoplast regeneration of Amycolatopsis orientalis subsp. eremomycini producing eremomycin leads to the change of cultural and morphological properties as well as synthesis of secondary metabolites. Formation of plus-variants with enchanced antibiotic production was promoted by UV-irradiation of protoplasts.

[The hypolipidemic action of antibiotic 86/88 (enniatin B) in a hepatoblastoma G2 cell culture].

A cyclodepsipeptide antibiotic 86/88 (enniatin B) with strong hypolipidemic action was isolated from the culture liquid of the fungus INA F-86/88 identified as Fusarium lateritium Nees var. stilboides (Wr.) Bilai.

[The cytotoxicity of mevalonate, lovastatin and carminomycin with respect to MOLT-4 human malignant T-lymphoblasts in vitro].

It was shown in vitro that high concentrations of lovastatin, a competitive inhibitor of hydroxymethyl glutaryl coenzyme A (HMG-CoA) reductase inhibited human malignant cells MOLT-4. The activity of lovastatin in doses of 50-250 microM was dose-dependent. Addition of mevalonate in a concentration of 3 mM to the growth medium completely prevented the cytotoxic effect of 100 microM of lovastatin.

[Induction of antibiotic production in inactive cultures of actinomycetes. Monensin production by a mutant strain 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.

[Induction of antibiotic formation by inactive cultures of actinomycetes. A mutant strain of Streptomyces helvaticus, a new producer of bruneomycin].

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).

[Antibiotic production by inactive cultures of actinomycetes after treatment with ethidium bromide].

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.

[Use of the protoplast fusion and regeneration method for screening antibiotic producers among inactive strains of Streptomyces].

Intraspecies fusion of protoplasts of two strains of Streptomyces fradiae, i.e native protoplasts of an inactive strain INA 00708 and heat inactivated protoplasts of a neomycin-producing strain ATCC 10745, and regeneration of the protoplasts of the inactive strain INA 00708 resulted in formation of clones producing neomycin and clones synthesizing antibiotics of an unknown nature differing from neomycin. All the active clones were unstable and lost their antibiotic activity in subcultures.

[Protoplast fusion in Streptomyces fradiae strains producing neomycin and tylosin].

Interspecies fusion of protoplasts of the Streptomyces fradiae strains producing neomycin (an aminoglycoside antibiotic) and tylosin (a macrolide antibiotic) was performed with a view to isolate strains producing novel antibiotics. Fusion of the protoplasts of the neomycin- and tylosin-producing strains labelled by the resistance to monomycin and lincomycin, respectively, caused no formation of stable strains producing antibiotics differing in chromatographic mobility from the antibiotics produced by the initial strains. In fusion of the protoplasts of the unlabelled strains, heat-inactivated protoplasts of the active line of one strain (donor) and native protoplasts of the inactive line of the other strain (recipient) were used.

[Comparative study of Streptomyces--producer of aminoglycoside antibiotics, monomycin and kanamycin, and the strain 344 obtained by fusion of their protoplasts by the method of restrictive total DNA fingerprinting].

The method of total DNA restriction finger prints was applied to the study of Streptomyces monomycini INA 1465 producing monomycin, Streptomyces kanamyceticus INA K-13 producing kanamycin and strain 344 isolated after fusion of the protoplasts of strain 1465 and K-13, which produced albofungin and chloralbofungin, aminoglycoside antibiotics. For preparing the finger prints of the strains splitting by endonucleases BamHI, PstI, PvuII, and BgIII was used. The finger prints showed that strain 344 was related to the strain of S.

[Albofungin formation by a strain isolated as a result of fusion of protoplasts of organisms producing aminoglycoside antibiotics].

Strain 344 synthesizing an antibiotic complex was isolated after fusion of the protoplasts of Streptomyces monomycini producing monomycin and Streptomyces kanamyceticus producing kanamycin. The major component of the complex was identified with albofungin and the minor one was suggested to be chloralbofungin. In the cultures of strain 344 variants forming monomycin were detected.

[Semisynthetic derivatives of daunorubicin and carminomycin: inhibition of DNA synthesis after intravenous administration to mice].

Inhibition of DNA synthesis in the liver, kidneys, spleen and heart of mice after intravenous administration of 0.1 and 0.3 LD50 of semisynthetic derivatives of rubomycin (daunorubicin) and carminomycin was studied.

[Transformation of anthracycline antibiotics and their semisynthetic derivatives as affected by the liver aldo-keto reductase of rats].

Formation of 13-dihydro derivatives of rubomycin (daunorubicin), carminomycin, doxorubicin and some of their semisynthetic derivatives under the effect of pure aldo-keto reductase from the rat liver was studied. Attachment of an oxy group to C-14 markedly retarded formation of the 13-dihydro derivatives while attachment of the bulky radicals to the same position prevented their formation. Binding of the anthracycline antibiotics to human serum albumin had no impact on the fermentative reaction rate.

[Suppression of DNA synthesis in mice by the anthracycline antibiotics daunorubicin, carminomycin and doxorubicin].

Inhibition of DNA synthesis by rubomycin (daunorubicin), carminomycin and doxorubicin in the spleen, liver, kidneys and heart was studied on mice. The antibiotics were administered intravenously in a dose of 0.3 LD50.

[Isolation and regeneration of Micromonospora olivoasterospora protoplasts].

The conditions for preparation and regeneration of the protoplasts of M. olivoasterospora were developed. It was found that effective formation of the protoplasts required preliminary cultivation of M.

[Regeneration of Nocardia orientalis protoplasts].

A method for effective regeneration of the protoplasts of N. orientalis, a vancomycin-producing organism into viable cells on a rich organic medium was developed. The dependence of the regeneration on the conditions of the protoplast plating out and the level of the regeneration medium dehydration was studied.

[Interaction with DNA of semisynthetic carminomycin and rubomycin derivatives].

The apparent binding constants and the effect of semisynthetic derivatives of carminomycin and rubomycin (anthracycline antibiotics) on DNA fusion were studied. The following semisynthetic derivatives were used. 13-dihydrocarminomycin, 14-hydroxycarminomycin, 13-(4-methylpiperazinyl) imine carminomycin, 13-benzoylhydrazone carminomycin (carminazone), 13-tret-butoxycarbonyl hydrazone rubomycin, 13-(4-methylpiperazinyl) imine rubomycin, 14-(1-hydroxyl-2,2,6,6-tetramethylpiperidyl-4)-acetoxyrubomycin (spin-labeled rubomycin).