[Effect of cultivation conditions of Streptomyces globisporus 3-1 on landomycin E production].

The producing of antitumor angucycline antibiotic landomycin E has been studied in dynamics of the surface and deep growth of Streptomyces globisporus 3-1 on different full-value media--soya, maize and peptone-yeast media. It is shown that the highest yield of landomycin E is observed on the maize, a bit lower--on soya, and the lowest--on peptone-yeast media independent of the method of growing. The antibiotic stability is affected by alkali pH of the medium. Growth dynamics of the culture in the maize and soya media in the laboratory 2-litre fermenter is characterized by intensive assimilation of glucose, absorption of dissolved oxygen, accumulation of biomass and landomycin E from the 24th to 48th hour of fermentation. The antibiotic is synthesized as primary metabolite reaching its maximum (180-200 mg/l) for the 48th hour of the culture growth. A hypothesis is put forward on the inhibition of the two-component system of signals transduktion by isoflavone genistein, which stimulates synthesis of landomycin E.

[Antibiotic sensitivity of microorganisms, isolated from patients with opportunistic infections].

Data of resistance of 642 bacterial strains dominating among opportunistic infections to different classes of antibiotics were presented. Staphylococcus, Pseudomonas and Enterobacteriaceae were this group representatives. Antibiotics which may be recommended for empirical therapy were revealed. Other antimicrobial drugs may be used after establishing the agent sensitivity using standard discs.

[Some properties of a mutant of Streptomyces globisporus 1912 supersensitive to ultraviolet radiation]. / Deiaki vlastyvosti nadchutlyvoho do ul'trafiuletu mutanta Streptomyces globisporus 1912.

A well-sporulating mutant Spo 1 has been isolated after the action of defective phage from the zone of total lysis of Streptomyces globisporus 1912. It has been shown, that mutant Spo 1 is supersensitive to the action of ultraviolet radiation and has the increased sensitivity to the action of methyl-methane-sulfonate, has mutation in the cluster of genes of synthesis of landomycin E and is not sensitive to the action of nitrous acid and hydrogen peroxide. Spo 1 also has a high level of UV-mutability. After the action of UV on spores 4620 colonies were analysed and 17 auxotrophic mutants (0.36%) were selected. Four auxotrophs restored their ability to produce landomycin E and a partial block of synthesis of the antibiotic was observed in six auxotrophs. Seven of white (lnd E) auxotrophs were analysed with the help of a system "secretor-conventer" and it has been shown that two mutants do not synthesize daidzeine flavonoide and have genotype lnd E dai aux uvs, five of them were capable to synthesize this flavonoide and have genotype lnd dai(+) aux uvs. Initial species of S. globisporus 1912 has increased sensitivity to lethal action of UV. It is supposed that mutant Spo 1 bears two uvs-mutations.

[Sensitivity of Streptomyces globisporus 3-1--a highly active producer of landomycin E to its own and the other polyketide antibiotics]. / Chutlyvist' Streptomyces globisporus 3-1--vysokoaktyvnoho produtsenta landomitsynu E do vlasnoho ta inshykh poliketydnykh antybiotykiv.

The strain Streptomyces globisporus 3-1--a highly active producer of a new anticarcinogenic antibiotic landomycin E from the group of angucyclins has been studied for its resistance to its own and known polyketide antibiotics--tetracycline, oleandomycin and doxorubicine as well as to aminoglycoside antibiotic streptomycin. The survival of mycelium of the strain 3-1 was established to depend on antibiotics concentration. Four equal resistances of streptomycete to antibiotics within the concentration of 5-30 micrograms/ml have been shown. The survival of the strain 3-1 mycelium fragments at 5 micrograms/ml of antibiotic is for tetracycline--1.8, for olcandomycin--0.7; doxorubicin and landomycin E--(-0.7) and streptomycin--(-4.6) l g%. As to their intensity of the lethal effect on the strain 3.1 antibiotics show the following descending succession: streptomycin, landomycin E, doxorubicin, olcandomycin and tetracyclin. High sensitivity of the strain 3-1 to the lethal effect of its own antibiotic may be explained by high permeability of mycelium fragments to landomycin E as compared to the intact mycelium.