Dissulfurirhabdus thermomarina gen. nov., sp. nov., a thermophilic, autotrophic, sulfite-reducing and disproportionating deltaproteobacterium isolated from a shallow-sea hydrothermal vent T , was isolated from a shallow, submarine hydrothermal vent (Kuril Islands, Russia). Cells of strain SH388 T were Gramstain-negative short rods, 0.2-0.4 µm in diameter and 1.0-2.5 µm in length, and motile with flagella. The temperature range for growth was 25-58 C (optimum 50 C), and the pH range for growth was pH 5.0-7.0 (optimum pH 6.0-6.5). Growth of strain SH388T was observed in the presence of NaCl concentrations ranging from 0.5 to 4.0 % (w/v) (optimum 2.0-2.5 %). The strain grew chemolithoautotrophically with molecular hydrogen as electron donor, sodium sulfite as electron acceptor and bicarbonate/CO 2 as a carbon source. It was also able to grow by disproportionation of sulfite and elemental sulfur but not thiosulfate. Sulfate, Fe(III) and nitrate were not used as electron acceptors either with H 2 or organic electron donors. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the isolate belonged to the class Deltaproteobacteria and was most closely related to Dissulfuribacter thermophilus and Dissulfurimicrobium hydrothermale (91.6 % and 90.4 % sequence similarity). On the basis of its physiological properties and results of phylogenetic analyses, strain SH388 T is considered to represent a novel species of a new genus, for which the name Dissulfurirhabdus thermomarina gen. nov., sp. nov. is proposed. The type strain of the species is SH388 T (=DSM 100025. It is the first thermophilic disproportionator of sulfur compounds isolated from a shallow-sea environment.Chemolithoautotrophic micro-organisms can gain energy from a variety of inorganic compounds serving as electron donors and acceptors. Sulfur dioxide is one of the most typical and abundant volcanic gases. It is highly soluble in water; thus, in aquatic environments, including hydrothermal vents, SO 2 is usually present in the form of sulfite ions. Micro-organisms capable of dissimilatory sulfite reduction are phylogenetically diverse and include all sulfate-reducers as well as many nonsulfate-reducing species. Overall, the ability to use sulfite as an electron acceptor with organic or inorganic electron donors is known for representatives of the bacterial phyla Firmicutes, Proteobacteria, Nitrospirae and Thermodesulfobacteria and for archaea of the phyla Crenarchaeota and Euryarchaeota (Simon & Kroneck, 2013; Slobodkin et al., 1999). Some sulfite-reducers are also capable of sulfite disproportionation. Growth coupled to disproportionation of sulfite
A homogeneous glutamyl endopeptidase splitting peptide bonds of glutamic, rarely of aspartic acid residues in peptides and proteins, was isolated from Bacillus intermedius 3-19 culture filtrate using chromatography on CM cellulose and Mono S. The enzyme molecular mass is equal to 29 kDa, pi 8.4. The protease is inhibited by diisopropylfluorophosphate. The enzyme, like other glutamyl endopeptidases, reveals two pH optima at pH 7.5 and 9.0 for casein and one at pH 8.0 for Z-GlupNA hydrolysis. A 6 mM K m is found for hydrolysis of the latter substrate. The enzyme activity optimum lies at 55°C, and it is stable at pH 6.5-11.0. Its N-terminal sequence shows 56% coinciding residues when compared with that of Bacillus licheniformis glutamyl endopeptidase.
The aeration-dependent changes in content of various quinones in Escherichia coli were found to be unaffected by a prokaryotic translation inhibitor chloramphenicol. In addition, this process was shown to be completely intact in cells with mutated fnr, arc and appY loci. It is assumed that E. coli possesses a special system of oxygen-dependent post-transcriptional regulation of the quinone biosynthetic pathways.
Inmirania thermothiophila gen. nov., sp. nov., a thermophilic, facultatively autotrophic, sulfur-oxidizing gammaproteobacterium isolated from a shallow-sea hydrothermal vent , was isolated from a thermal spring located in a tidal zone of a geothermally heated beach (Kuril Islands, Russia). Cells of strain S2479T were rod-shaped and motile with a Gram-negative cell-wall type. The temperature range for growth was 35-68 8C (optimum 65 8C), and the pH range for growth was pH 5.5-8.8 (optimum pH 6.5). Growth of strain S2479 T was observed in the presence of NaCl concentrations ranging from 0.5 to 3.5 % (w/v) (optimum 1.5-2.0 %). The strain oxidized sulfur and thiosulfate as sole energy sources for autotrophic growth under anaerobic conditions with nitrate as electron acceptor. Strain S2479 T was also capable of heterotrophic growth by reduction of nitrate with oxidation of low-chain fatty acids and a limited number of other carboxylic acids or with complex proteinaceous compounds. Nitrate was reduced to N 2 . Sulfur compounds were oxidized to sulfate. Strain S2479 T did not grow aerobically during incubation at atmospheric concentration of oxygen but was able to grow microaerobically (1 % of oxygen in gas phase). Phylogenetic analysis based on 16S rRNA gene sequences indicated that the strain was a member of the family Ectothiorhodospiraceae, order Chromatiales, class Gammaproteobacteria. On the basis of phylogenetic and phenotypic properties, strain S2479 T represents a novel species of a new genus, for which the name Inmirania thermothiophila gen. nov., sp. nov. is proposed. The type strain of the type species is S2479
(Cytosine-5)-DNA methyltransferase SsoII (M.SsoII) functions as a methyltransferase and also as a transcription factor. Chemical and photochemical crosslinking was used for exploring the structure of M.SsoII-DNA complexes and M.SsoII in the absence of DNA. Photocrosslinking with 4-(N-maleimido)benzophenone demonstrated that in the M.SsoII complex with DNA containing the regulatory site, the M.SsoII region responsible for methylation was bound to DNA flanking the regulatory site, which contained no methylation sequence. This required high flexibility of the linker connecting the M.SsoII N-terminal domain and the M.SsoII region responsible for methylation. The flexibility was demonstrated by crosslinking with bis-maleimidoethane and 1,11-bis-maleimidotetraethyleneglycol.
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