[Bacterial pigment prodigiosin and its genotoxic effects].

The prodigiosin preparation was isolated and purified from Serratia marcescens ATCC 9986, using chromatographic methods. The analysis of the preparation by TLC, NMR-spectrometry and mass-spectrometry allowed to confirm the red pigment fraction as the prodigiosin and detect its purity. Originally, the specific features of the toxic and genotoxic effects of prodigiosin and the possibility of induction of mutations by pigment in the cells of Salmonella typhimurium TA 100 (Ames test) and chromosome damage of mammalian erythroblasts have been determined.

[The accumulation of proteins with chitinase activity in the culture media of the parent and mutant Serratia marcescens strain grown in the presence of mitomycin C].

The study of the accumulation pattern of extracellular proteins with chitinase activity in the parent Serratia marcescens strain Bú 211 (ATCC 9986) grown in the presence of mitomycin C and its mutant strain with the constitutive synthesis of chitinases grown in the absence of the inducer showed that chitinase activity appeared in the culture liquids of both strains at the end of the exponential phase (4 h of growth) and reached a maximum in the stationary phase (18-20 h of growth). The analysis of the culture liquids (12 h of growth) by denaturing electrophoresis in PAAG followed by the protein renaturation step revealed the presence of four extracellular proteins with chitinase activity and molecular masses of 21, 38, 52, and 58 kDa.

[Phosphatase from Proteus mirabilis].

Cell-free preparations of Proteus mirabilis contained a phosphatase (EC 3.1.3.

[Endonuclease from Proteus mirabilis].

Two isoforms of nuclease displaying DNase and RNase activities were found in the culture liquid and periplasm of Proteus mirabilis. The enzyme was isolated from the periplasm and then purified to a functionally homogeneous state. The nuclease was equally potent in cleaving denatured and native DNAs by the endonuclease mechanism and was designated Pm endonuclease.

[Biosynthesis of Proteus mirabilis nuclease].

The culture liquid and periplasm of Proteus mirabilis contained nuclease, an enzyme with DNase and RNase activities. The nuclease was most actively synthesized in the early exponential and stationary growth phases. Nuclease synthesis was regulated by nucleic acids (induction by substrate) and inorganic phosphate (end-product inhibition).

[Effect of nalidixic acid and mitomycin C on growth and biosynthesis of extracellular proteins by Serratia marcescens].

The effect of various concentrations of nalidixic acid and mitomycin C on the dynamics of growth of Serratia marcescens and synthesis of endonuclease and other extracellular enzymes by it was studied. The synthesis of extracellular endonuclease was induced during inhibition of the cell division under the effect of nalidixic acid and mitomycin C. The induction of the endonuclease synthesis preceded the start of the division of the resistant cells which overcame the phase of the population retarded growth.

[Induction of synthesis of extracellular DNAase from Proteus mirabilis under the effect of compounds, blocking DNA replication].

The effects of mitomycin C and nalidixic acid on the biosynthesis of extracellular endodeoxyribonuclease in Proteus mirabilis have been studied. The presence of both antibiotics in the periodic and short-time cultures of washed off cells has increased both the activity of the DNAse and protein yield in cultural liquid and bacterial cells. PAGE-electrophoresis has shown the effect of mitomycin C to increase or induce the synthesis a large number of Proteus mirabilis extracellular proteins.

[Induction of intracellular endonuclease synthesis in Serratia marcescens by agents suppressing DNA replication].

Endonuclease synthesis in Serratia marcescens was studied in the presence of agents selectively suppressing DNA biosynthesis: nalidixic acid, mitomycin, hydroxyurea and thymine limitation. All the agents suppressing DNA replication induced exocellular endonuclease biosynthesis irrespective of their action mechanism. The greatest inducing effect was exerted when the agents were added to cells in the late exponential phase.

[Effect of mitomycin on the biosynthesis of extracellular endonuclease by Serratia marcescens].

The effect of mitomycin C on extracellular endonuclease activity of Serratia marcescens was studied. It was shown that in a concentration of 0.02-1.

[Deoxyribonuclease from Corynebacterium diphtheriae: dynamics of synthesis and properties].

Diphtheritic bacteria of PW-8 Massachusetts strain produced into cultural medium only one nucleotidase--endoDNAase. The enzyme was synthesized by the cells during the exponential phase of growth. The DNAase was purified 500-fold and exhibited properties specific to neutral-alkaline DNAases (pH optimum about 7.

[Deoxyribonuclease of Proteus mirabilis].

DNAase was isolated and purified from cell-free extracts of Proteus mirabilis by means of fractionation with ammonium sulfate and CM cellulose chromatography. The enzyme exhibited the endonuclease specificity with DNA as a substrate, split off the native DNA by the "single-strike" mechanism, had a pH optimum in alkaline zone, required Me2+ and was inhibited by tRNA. The highest specific activity and the specific rate of the enzyme synthesis were found at lag phase, before the exponential phase of the cell population growth.

[Comparative study of the energy metabolic enzymatic activity of pigmented and pigment-free strains of Serratia marcescens].

The activity of enzymes involved in energy metabolism was investigated in the pigmented strain of Serratia marcescens and in its pigmentless variant with an elevated activity of nuclease. The pigmentless strain was found to exhibit a higher specific activity of several enzymes participating in glycolysis, the pentose phosphate cycle, and the citric acid cycle. The pigmentless strain accumulated lesser amounts of lactic acid in the medium and was characterized by the negative Voges--Proskauer reaction.

[Effect of exogenous factors on extracellular alkaline ribonuclease synthesis in Bacillus mesentericus].

Bacillus mesentericus was found to assimilate nucleic acids as a source of nitrogen and phosphorus. Nucleic acids added to the medium as a source of nitrogen or phosphorus stimulated synthesis of ribonuclease. When washed bacterial cells were incubated for a short period of time in a fresh nutrient medium containing RNA, synthesis of RNAase was also induced.

[Various physiological aspects of Serratia marcescens pigmented strains and their pigmentless variants with an elevated nuclease activity].

Some aspects of physiology of Serratia marcescens pigmentless variants with elevated nuclease activity were studied. The variants are characterized by a higher respiration rate when glucose, glycerol, inositol or maltose are used as an energy substrate, a higher respiration quotient, a lower growth rate, a lower economic coefficient, and a lower thermogenesis. The growth of Serratia marcescens pigmentless strains is presumed to be unbalanced.

[Intracellular nucleodepolymerase of bacteria, representatives of the Proteus and Providencia groups. Its isolation and properties].

High activity of enzymes, splitting native, denaturated DNA, deoxyribooligonucleotides and RNA, was observed in cell free extracts of bacteria--representatives of 5 strains of Proteus-Providencia. Some properties of nucleases were studied in cell free extracts. In the bacteria studied DNAases were thermolabile proteins, which were completely inactivated at 50-60 degrees, RNAases were more thermostable.