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D A Perumov

Publications and source records attributed to D A Perumov.

At least 37 records · Page 2Linked to original sources
PubMed1983

[Mutagenic action of O-methlhydroxylamide on transforming DNA].

The mutagenic effect of O-methylhydroxylamine (OMHA) on transforming DNA of Bacillus subtilis was studied. In accordance with the earlier reported chemical and functional data, the mutagenic effect was observed at 4.5 and 6.0 pH. An increase in pH caused a decrease in the rate of mutagenesis, though the maximal level of mutagenesis was equal at both values of pH. The results obtained with recipients defective in the system of UV-repair revealed that both products of reaction of OMHA with the cytosine-base of DNA, N4-metoxycytidine and N4-metoxy-6-metoxyamino-5,6-dihydrocytidine, are effectively eliminated through the system of UV repair.

Bacillus subtilis↗
PubMed1979

[Operon of riboflavin biosynthesis in Bacillus subtilis. XVI. Localization of the ribC-group markers on the chromosome].

Regulatory markers of ribC group were located on the chromosome of Bacillus subtilis by means of genetic transformation. Markers of this group controlling the regulation of riboflavin biosynthesis were mapped between markers of resistance to acriflavin and streptomycin (strC group). The value of cotransfer index between acriflavin-resistance markers and ribC markers was found to be 26--32%. Acriflavin inhibits the riboflavin biosynthesis. The level of inhibition depends on the genotype of riboflavin-producing strains, while the inhibition of the cell growth does not depend on it.

Bacillus subtilis↗
PubMed1978

[Riboflavin biosynthesis operon of Bacillus subtilis. XIV. Operator-constitutive mutants].

Numerous operator-constitutive mutants of riboflavin biosynthesis were selected. All of them map in a short region of the Bacillus subtilis chromosome. The yield of riboflavin synthetase from this mutant is different, but in most cases much lower than the maximal yield from a repressor minus strain. Our tentative explanation is a partial overlap of the sites for the adsorption of repressor and RNA-polymerase. Therefore the affinity to the transcribing enzyme is diminished in the operator constitutive strains. The affinity of the repressor-effector complex to the operator depends on the effector structure.

Bacillus subtilis↗
PubMed1978

[Operon of riboflavin biosynthesis in Bacillus subtilis. XV. A study of mutants related to the initial stages of biosynthesis. The origin of the ribityl chain of the riboflavin molecule].

The incorporation of 14C-labelled guanosine and xanthosine into riboflavin was studied. It is concluded that the ribose mojety of guanosine is converted to the ribityl side chain of riboflavin. Thus the immediate precursor of riboflavin biosynthesis is a guanosine compound. Two classes of the riboflavin-dependent mutants of Bacillus subtilis were studied. They are closely linked to the lysine markers and probably correspond to the initial steps of riboflavin biosynthesis pathway.

Bacillus subtilis↗
PubMed1977

[Operon study of riboflavin biosynthesis in Bacillus subtilis. XII. The determination of the ATP:riboflavin-5'-phosphotransferase and riboflavinsynthetase content in the cells with varying genotypes].

Activities of riboflavinkinase and riboflavinsynthetase were measured in 15 strains of Bacillus subtilis with different genotype. The increased level of riboflavinkinase was observed in strains, resistant to lumiflavin or lumichrome. Specific activity of riboflavinkinase was found to be about 100 times lower than that of riboflavinsynthetase. The regulation of biosynthesis of these enzymes seems to proceed non-coordinately. This phenomenon can be the sequence of the existence of many operators, controlling the flavinogenesis in Bac. subtilis.

Bacillus subtilis↗
PubMed1977

[Riboflavin biosynthesis operon of Bacillus subtilis. XIII. Genetic and biochemical study of mutants with regard to intermediate stages of biosynthesis].

New riboflavin dependent mutants of Bacillus subtilis accumulating different pteridines were studied. The data obtained show that the formation of ribityl side chain proceeds in a few steps at least on a part of riboflavin precursors. The oxidation of connected ribosyl into ribulose with subsequent restoration of it into ribityl proceeds at first. The corresponding genes are located on terminal part of riboflavin operon, as show the results of two-factor transformational crosses with different donors and recipients.

Bacillus subtilis↗
PubMed1976

[Operon for riboflavin synthesis in Bacillus subtilis. XI. Determination of the type of regulation using a test for dominance of operator-constitutive and regulator-constitutive mutations].

The strain GSY 468 of Bacillus subtilis, giving persistent unstable merozogotes was used as recipient in transformation. Diploid cells bearing a regulator constitutive or operator constitutive mutation were obtained, and their phenotype was studied. The operator constitutive mutation behaves as a dominant one, but the regulator constitutive is recessive. Hence the regulation type in riboflavin operon is negative. The product of the regulator gene is obviously a repressor protein.

Bacillus subtilis↗
PubMed1975

[Operon of riboflavin biosynthesis in Bacillus subtilis. VIII. Localization of group ribC markers in relation to the structural gene cluster group].

Regulatory markers of ribC group were located on the chromosome of Bacillus subtilis by means of genetic transformation using DNA isolated by the phenol-benzoate method of Kelly. Markers of this group controlling the regulation of riboflavin biosynthesis were mapped in the terminal region of the chromosome between phe and lys markers. A maximal value of contransfer index between ribC 1 and lys42 markers was found to be 3.5%.

Bacillus subtilis↗
PubMed1975

[Operon of riboflavin synthesis in Bacillus subtilis. IX. Preparation and properties of lumiflavin- or lumichrome-resistant mutants].

Lumiflavin and lumichrome both inhibit the growth of different strains of Bacillus subtilis including riboflavin-constitutive mutant. Lumiflavin has no regulating effect, but lumichrome is an effector and it participates in the repression of riboflavin precursors synthesis and the synthesis of riboflavinsynthetase. Mutants resistant to lumiflavin or lumichrome accumulate a mixture of riboflavin, FMN and FAD. Their regulatory characteristics are substantially altered. They are repressed by higher concentrations of all effectors comparing with the wild type. The mapping of resistant mutants showed that the most of them are located near to ribC gene, probably inside of it. The simultaneous presence of all three flavins in the cultural medium shows that the regulatory protein is universal to the biosynthesis of all flavins.

Bacillus subtilis↗