[The action of hydrogen peroxide on mutants of Streptomyces globisporus 1912 with different carotene-synthesizing activity].

The paper deals with dependence of survival of Crt(+)- and Crt- mutants of Streptomyces globisporus 1912 in conditions of oxidizing stress caused by hydrogen peroxide on the level of lycopene and beta-carotene biosynthesis. Pink mutants 4Lcp, RVLcp and R3Lcp, which produce lycopene, are the most resistant to hydrogen peroxide. Red mutants 4Crt, 6Crt, 7Crt, 7Y RVCrt, R3Crt--producers of lycopene and beta-carotene have the average level of resistance to H2O2. Pigmentless mutants (Crt-) 4W, 4W1, 7W2 and yellow one 7Y have preserved sensitivity to H2O2 characteristic of the initial strain 1912.

[Streptomyces globisporus 1912 mutants highly sensitive to ultraviolet radiation, their antibiotic activity and reparation ability].

Twenty five mutants defective in biosynthesis of antitumor antibiotic landomycin E and 22 mutants with higher level biosynthesis of this antibiotic were obtained after nitrosoguanidine mutagenic treatment of wild strain of Streptomyces globisporus 1912 spores. Six of them (5 mutants of LndE and 1 mutant of LndE+) were found to carry uvs-mutation responsible for high level UV-sensitivity. Uvs-mutants 1912-11 and 1912-16 were highly sensitive to the action of nitrous acid, hydrogen peroxide and methyl-methane-sulfonate.

[Resistance of the colored and non-pigmented mutants of Streptomyces globisporus 1912 to the action of UV-rays].

The lethal action of ultraviolet rays has been studied on colored 4Crt, 4Lcp, 6Crt, 7Crt and white 4W, 4W1, 7Y, 7W2, 7W6 mutants of S. globisporus 1912. It was shown, that all studied mutants are more resistant to action of ultraviolet light in comparison with initial strain 1912.

[Biosorption ability of mutants of Rhodotorula mucilaginosa UCM Y-1776].

Twenty stable mutants with various coloration intensity have been allocated in carotene-synthesizing natural strain Rhodotorula mucilaginosa UCM Y-1776 (wild type) after nitrosoguanidine action. Two brightly orange mutants 4L and 11 and one non-pigmented mutant 2 were chosen for the further researches. The ultraviolet was inefficient as a mutagen. Resistance to high concentration of copper ions (up to 200 mg/g), high sorption ability (Qmax = 9.1 mmol/g) was characteristic of R. mucilaginosa UCM Y-1776. Concentration of copper ions 50 mg/l was toxic for mutants 4L, 11 and 2, which sorption ability was lower in comparison with carotene pigmented R. mucilaginosa UCM Y-1776. It was shown, for the first time that there was a direct dependence between the presence of carotenoid pigments, resistance to high concentration of copper ions and sorption ability for yeast R. mucilaginosa UCM Y-1776.

[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.

[Spontaneous and induced variability of Streptomyces aureofaciens--chlortetracycline producer]. / Spontanna ta indukovana minlyvist' Streptomyces aureofaciens--produtsenta khlortetratsyklinu.

Spontaneous and induced variability of Streptomyces aureofaciens strain T[symbol: see text] 633 [symbol: see text] and its variants has been investigated. Correlative relation between the antibiotic formation and colonies morphology was observed. Combined effect of nitrosoguanidine and UV-beams resulted in the obtaining of 27 variants which exceeded activity of strain T[symbol: see text] 633 [symbol: see text] by 30-35% and were stable as to antibiotic biosynthesis during 7-10 generations.

[The isolation and characteristics of mutant Streptomyces globisporus 1912 defective for landomycin E biosynthesis]. / Oderzhannia i kharakterystyka mutantiv Streptomyces globisporus 1912, defektnykh po biosyntezu landomitsynu E.

Mutants defective in the synthesis of antitumor angucycline antibiotic landomycin E were obtained from the asporogenic and initial sporulating strains of Streptomyces globisporus 1912 by means of nitrosoguanidine treatment and UV-irradiation of the mycelium fragments and protoplasts. The frequency of induction of LanE mutants in the protoplasts of strain 3-1 was 3 times higher (0.55%) as compared to mycelium fragments (0.17%). After mutagenic treatment of spores the yield of such mutants was lower (0.044-0.071%). It was shown, that izoflavon daidzein was an effective and necessary regulator of the landomycin E synthesis. The collection of 53 landomycin defective mutants was divided into three groups on the basis of their ability to produce antibiotic and regulator: 1) mutants LanE-Dai+ (45 strains), which did not synthesize landomycin E, but produced daidzein; 2) mutants LanE+Dai- (4 strains), which could restore landomycin E synthesis after adding exogenic daidzein to the medium and 3) mutants LanE- Dai- which did not synthesize landomycin E in the presence of daidzein.

[The induction of mutations in Streptomyces aureofaciens by UV rays and nitrosoguanidine and the identification of the mutants obtained]. / Induktsiia mutatsii u Streptomyces aureofaciens UF-promenniamy i nitrozohuanidynom ta identyfikatsiia oderzhanykh mutantiv.

Streptomyces aureofaciens 019(8), chlortetracycline producent was subjected to the effect of UV-light and nitrosoguanidine and after that its 121520 colonies have been analyzed by the methods of replicas and 57 mutants were isolated: sensitive to the effect of UV radiation--14; auxotrophs--30; antibiotic-inactive --13. The induction frequency of mutations is within the limits of 0.016 to 0.067%. Auxotrophic mutants manifested genetic instability. Mutants with a block chlortetracyclin biosynthesis are stable.

[The mutagenic action of radioactive contaminants of feed and food products on strains TA98 and TA100 of Salmonella typhimurium]. / Mutahenna diia radioaktyvnykh zabrudnen' kormiv i produktiv kharchuvannia na shtamy TA98 i TA100 Salmonella typhimurium.

Radionuclide-polluted slices of beef (2775 Bq/kg), pork (274.8 Bq/kg), potato (159.0-444.0 Bq/kg), carrot, garden beet, kidney bean and sorrel (44.5-460.0 Bq/kg) have been studied for their mutagenic effect on the tester strains TA98 and TA100 of Salmonella typhimurium and this index as a rule correlates with the level of the slices pollution. On the other hand the slices of cabbage and samples of rye and wheat (46.0-460.0 Bq/kg) as well as fish (2314.0 Bq/kg) had no mutagenic effect on these strains. The samples of milk (230.0-581.5 Bq/1) also did not evoke the increase of mutagenesis level while high concentrations of these preparations (20 mg/ml, and above) manifested toxic effect on the mentioned strains.