Phenotypic Characteristics of Bacillus subtilis Mutants with Decreased Activity of Exonuclease I

A Bacillus subtilis strain containing a mutation decreasing exonuclease I activity by up to 25% as compared to normal cells of the original BD46 strain was developed. A decrease in B. subtilis exonuclease I activity increased the sensitivity of mutant cells to UV irradiation and mitomycin C, decreased the frequency of recombination during chromosomal transduction and transformation, decreased the frequency of transposon Tn917 translocation from plasmid to the bacterial chromosome, and did not affect the frequency of plasmid transformation. The corresponding mutation was mapped

Phenotypic characteristics of bacillus subtilis mutants with decreased activity of exonuclease i

A Bacillus subtilis strain containing a mutation decreasing exonuclease I activity by up to 25% as compared to normal cells of the original BD46 strain was developed. A decrease in B. subtilis exonuclease I activity increased the sensitivity of mutant cells to UV irradiation and mitomycin C, decreased the frequency of recombination during chromosomal transduction and transformation, decreased the frequency of transposon Tn9/7 translocation from plasmid to the bacterial chromosome, and did not affect the frequency of plasmid transformation. The corresponding mutation was mapped

The role of AmtB, GlnK and glutamine synthetase in regulation of of transcription factor TnrA in Bacillus subtilis

Nitrogen is a macroelement for all living cells, from bacteria to animals. Although ammonia ions (NH3/NH4 +) are toxic to animals, they are the most preferable nitrogen source for the majority of bacteria and are assimilated by glutamine synthetase (GS) in the so-called GOGAT cycle. A lack of nitrogen for a cell triggers cascade regulatory processes and activation of a large group of genes for utilization of nitrogen from other compounds. Thus, in Bacillus subtilis, genes of nitrogen metabolism are regulated by the transcription factor TnrA. In the cell, it is bound to AmtB-GlnK proteins, with interaction with glutamine synthetase repressing its DNA-binding activity. Deletion of the protein AmtB responsible for ATP-dependent transport of ammonium ions into the cell from the medium has been shown to lead to a lack of nitrogen in the cell and, as a result, to an increased level of expression of TnrA-regulon genes. With a deficit of protein GlnK, the factor TnrA is constitutively associated with GS, with its activity also decreasing under conditions of deficit of nitrogen source. The factor TnrA activity in cells seems to be constantly repressed by GS: in the absence of GS, the TnrA activity is significantly increased as compared with control, even under conditions of nitrogen starvation, in which GS is highly active. These facts allow it to be suggested that the factor TnrA activity is regulated by competitive binding to GS and protein GlnK. © 2013 Pleiades Publishing, Ltd

Особенности микробиологического состава вод реки Раздольной (южное Приморье)

Произведена оценка численности и ее сезонной изменчивости для различных индикаторных групп микроорганизмов в поверхностных водах р. Раздольной. Результаты исследования показали, что они подвержены высокому комплексному органическому, техногенному и микробиологическому загрязнению. В поверхностных водах р. Раздольной были выявлены эколого-трофические группы микроорганизмов, которые принимали участие в очищении вод реки. Однако из-за постоянного притока сточных вод бактерии не успевали перерабатывать поступающее органическое вещество, что указывает на неспособность данной экосистемы к полному самоочищению. Согласно классификатору качества вод, воды р. Раздольной по микробиологическим показателям отнесены к грязным в летний сезон, к загрязненным в весенний и осенний периоды и к чистым в зимний сезон

Seasonal hydrological and hydrochemical surveys in the Voevoda Bay (Amur Bay, Japan Sea)

Hydrological and hydrochemical surveys were conducted in the Voevoda Bay in May, August, and October, 2011 and February, 2012, in total 140 stations. Free water exchange of the bay with the Amur Bay is observed, with exception of its inner bights Kruglaya and Melkovodnaya. The water exchange is maintained by anticyclonic circulation with the inflow along the southern coast and outflow along the northern coast of the Voyevoda Bay. However, the opposite cyclonic circulation is observed in the Melkovodanaya Bight because of its coastal line patterns and fresh water discharge by the river. Dissolved oxygen content and partial pressure of CO2 in the bay waters are determined mostly by intensive processes of production and destruction of organic matter. There are three main groups of primary producers there, as diatom algae, sea grass Zostera marina , and periphyton. Specific chemical regime is formed in the Melkovodnaya Bight, in particular in winter when primary production depends on the ice cover and is driven by variations of photosynthetically active radiation passed through the ice. Seasonal variability of production-destruction processes intensity is discussed on the data of chemical parameters changes

Phenotypic Characteristics of Bacillus subtilis Mutants with Decreased Activity of Exonuclease I

A Bacillus subtilis strain containing a mutation decreasing exonuclease I activity by up to 25% as compared to normal cells of the original BD46 strain was developed. A decrease in B. subtilis exonuclease I activity increased the sensitivity of mutant cells to UV irradiation and mitomycin C, decreased the frequency of recombination during chromosomal transduction and transformation, decreased the frequency of transposon Tn917 translocation from plasmid to the bacterial chromosome, and did not affect the frequency of plasmid transformation. The corresponding mutation was mapped

Phenotypic characteristics of bacillus subtilis mutants with decreased activity of exonuclease i

A Bacillus subtilis strain containing a mutation decreasing exonuclease I activity by up to 25% as compared to normal cells of the original BD46 strain was developed. A decrease in B. subtilis exonuclease I activity increased the sensitivity of mutant cells to UV irradiation and mitomycin C, decreased the frequency of recombination during chromosomal transduction and transformation, decreased the frequency of transposon Tn9/7 translocation from plasmid to the bacterial chromosome, and did not affect the frequency of plasmid transformation. The corresponding mutation was mapped

Phenotypic characteristics of bacillus subtilis mutants with decreased activity of exonuclease i

A Bacillus subtilis strain containing a mutation decreasing exonuclease I activity by up to 25% as compared to normal cells of the original BD46 strain was developed. A decrease in B. subtilis exonuclease I activity increased the sensitivity of mutant cells to UV irradiation and mitomycin C, decreased the frequency of recombination during chromosomal transduction and transformation, decreased the frequency of transposon Tn9/7 translocation from plasmid to the bacterial chromosome, and did not affect the frequency of plasmid transformation. The corresponding mutation was mapped

Phenotypic Characteristics of Bacillus subtilis Mutants with Decreased Activity of Exonuclease I

A Bacillus subtilis strain containing a mutation decreasing exonuclease I activity by up to 25% as compared to normal cells of the original BD46 strain was developed. A decrease in B. subtilis exonuclease I activity increased the sensitivity of mutant cells to UV irradiation and mitomycin C, decreased the frequency of recombination during chromosomal transduction and transformation, decreased the frequency of transposon Tn917 translocation from plasmid to the bacterial chromosome, and did not affect the frequency of plasmid transformation. The corresponding mutation was mapped