Identification of important charged residues for alkali cation exchange or pH regulation of NhaH, a Na(+)/H(+) antiporter of Halobacillus dabanensis.

NhaH is a novel Na(+)/H(+) antiporter identified from the moderate halophile Halobacillus dabanensis. In this study, six conserved charged residues located in the putative transmembrane segments (TMS) including TMSV, TMSVI, TMSVIII and TMSXI of NhaH as well as two His residues in Loop III were replaced by site-directed mutagenesis for the identification of their potential roles in the antiport activity and pH regulation. Substitutions D137A, D166A and R325A caused a complete loss of Na(+)(Li(+))/H(+) antiport activity, revealing that D137, D166 and R325 are indispensable for the antiport activity.

Oceanobacillus manasiensis sp. nov., a moderately halophilic bacterium isolated from the salt lakes of Xinjiang, China.

Three Gram reaction positive, rod-shaped, moderately motile halophilic bacterial strains, designated YD3-56(T), YD16, and YH29, were isolated from the sediments of Manasi and Aiding salt lakes in the Xinjiang region of China, respectively. The strains grew optimally at 30-37 degrees C, pH 8-11, in the presence of 5-10% (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences revealed that the strains were closely related to members of the genus Oceanobacillus, exhibiting 99.

[Current status on proteomics of extremophilic microorganisms--a review].

We summarized the key handicap and troubleshooting when proteomic techniques were used to investigate extremophilic microorganisms, and the actual state of their proteomes research in recent years. Up to now, proteomics techniques keep developing and improving rapidly, but they has not been widely used to explore proteome of extremophilic microorganisms including halophiles, thermophiles, psychophiles, acidophiles and alkaliphiles due to specific problems including incomplete dissociation of protein-protein complexes of extremophiles, and a lot of proteins synthesized by extremophiles are resistant to the conditions which dissociated and denatured proteins synthesized by mesophilic organisms. However, the foreground of potential application of the techniques draws people on attempting zealously multifarious methods.

[Sodium ion transportation system and its possible mechanisms in bacteria].

Sodium ion with high concentration is toxic to living cells, and microorganisms adapt to the environment containing high concentration of salt by the strategies of salt-in-cytoplasm and compatible solutes. The Na+ extrusion system plays important roles in maintaining cytoplasmic Na+ homeostasis and pH level in microbial cells. Two possible mechanisms of Na+ circulation across the cytoplasmic membrane have been proposed, namely primary Na+ pump and secondary Na+/H+ antiporter.

[Study progress on compatible solutes in moderately halophilic bacteria].

Moderately halophilic bacteria which grow best in media with 3% to 15% salt constitute a heterogenous group of microorganisms which belong to different genera. These bacteria can inhabit the salt or soda lakes, coastal lagoons or man-made salterns. Moderately halophilc bacteria living in higher saline environments can not only cope with high osmotic stress but also adapt osmotic shock in short time.

[Biosynthesis of polyhydroxyalkanoates and its metabolic pathway in Comamonas sp. strain CNB-1].

Comamonas sp. strain CNB-1 degrades chloronitrbenzene and nitrobenzene for carbon and nitrogen sources. In this study, accumulation of polyhydroxyalkanoic acids (PHAs) within strain CNB-1 cells was investigated under various conditions.

Wenxinia marina gen. nov., sp. nov., a novel member of the Roseobacter clade isolated from oilfield sediments of the South China Sea.

An aerobic and heterotrophic, Gram-negative bacterial isolate, strain HY34(T), was isolated from sediment of an oilfield in the South China Sea, China. The taxonomy of strain HY34(T) was studied by phenotypic and phylogenetic methods. Strain HY34(T) formed faint-pink colonies on marine agar 2216.

Salegentibacter catena sp. nov., isolated from sediment of the South China Sea, and emended description of the genus Salegentibacter.

A novel marine bacterial strain, HY1T, was isolated from sediment of the South China Sea. The strain was aerobic and heterotrophic and formed saffron yellow-pigmented colonies on marine agar 2216. Cells were non-motile, Gram-negative rods, frequently occurring in chains.

[Two-dimensional gel electrophoresis analysis of moderately halophilic bacterium Halobacillus dabanensis D-8T under hypoosmotic shock condition].

Halobacillus dabanensis D-8T was isolated from the saline deposits of Daban lake in Xinjiang of China, and is able to grow in complex medium containing 0.5% to 25% salt. To figure out the survival mechanisms of Gram-positive moderately halophilic bacteria under hypoosmotic shock conditions, two-dimensional gel electrophoresis (2-DE) was carried out to investigate differential protein expression profiles of H.

Cloning and characterization of the genes encoding a glycine betaine ABC-type transporter in Halobacillus trueperi DSM10404T.

By using Southern blot hybridization and inverse polymerase chain reaction, a 5.5-kb DNA fragment was obtained from the genomic DNA of Halobacillus trueperi DSM10404(T). Sequence analysis revealed that it contained a potential operon with high levels of sequence similarity to the opuA operon encoding glycine betaine transporter from Bacillus subtilis, which is a member of the ATP-binding cassette (ABC) substrate binding the protein-dependent transporter superfamily.

Cyclobacterium lianum sp. nov., a marine bacterium isolated from sediment of an oilfield in the South China Sea, and emended description of the genus Cyclobacterium.

The marine bacterial strain HY9(T) was isolated from sediment from the South China Sea. Strain HY9(T) is aerobic, heterotrophic and rose-pigmented. The cells are non-motile and curved, i.

The pha2 gene cluster involved in Na+ resistance and adaption to alkaline pH in Sinorhizobium fredii RT19 encodes a monovalent cation/proton antiporter.

Sinorhizobium fredii RT19 can tolerate up to 0.6 M NaCl, whereas all its pha2-disrupted mutants, constructed by Tn5 mutagenesis, failed to grow in even the presence of 0.1 M NaCl.

[A Sinorhizoboium meliloti strain that can nodulate soybean plants].

Sinorhizobium meliloti XJ96077 was isolated from root nodules of alfalfa (Medicago sativa) in Xinjiang Region of China. Nodulation experiments showed that both soybean and alfalfa were effectively nodulated by XJ96077. The DNA (G+ C) mol% of strain XJ96077 was 61.

[Cloning, deletion and functional analysis of noeA from Sinorhizobium meliloti 042BM].

042BM noeA was obtained by PCR. It is identical to that of S. meliloti 1021 at 99% level, and similarity of their NoeA is 97%.

[The expression of gene related to salt tolerance from Sinorhizobium meliloti 042BM in Escherichia coli and purification of its fusion protein].

A 1.9kb DNA fragment related to salt tolerance of S. meliloti strain 042BM containing two open reading frames were obtained by PCR amplification and ligated into shuttle vector pBBR1-MCS2.

[Construction of the genomic library of Halobacillus sp. D8 and isolation of the glycine betaine transporter betH gene].

Halobacillus sp. D8 is a sporing-forming, gram-positive moderately halophilic bacterium which could tolerate up to 25% (W/V) NaCl. A genomic library of Halobacillus sp.

[Transcriptional regulation of noeAB from Sinorhizobium meliloti 042BM].

The expression regulation of S. meliloti 042BM noeAB was studied. The results showed that trigonelline could not elevate the level of noeAB expression, which indicated that these genes are not regulated by nodD2.

[Positional analysis of a gene related to salt tolerance in Sinorhizobium meliloti by transposon rescue].

Salt sensitive mutant 042BML-2 was obtained by mutating Sinorhizobium meliloti 042BM with transposon Tn5 carried on the plasmid pRL1063a. By transposon rescue, a 1.179 kb of DNA sequence of S.

Cloning and characterization of the Halobacillus trueperi betH gene, encoding the transport system for the compatible solute glycine betaine.

Halobacillus trueperi accumulates glycine betaine under condition of high osmolarity. A fragment of the glycine betaine transporter betH gene was obtained from the genome of H. trueperi with degenerate primers.

[Analysis of 16S rDNA sequences and DNA-DNA hybridization of moderately halophilic bacteria from Xinjiang region].

Based on the previous studies on numerical taxonomy and 16S rDNA PCR-RFLP analysis, the moderately halophilic bacteria isolated from Xinjiang Region constituted a new cluster, and the phylogenetic tree was constructed by comparing with the 16S rDNA sequences of the other moderately halophilic bacteria species. In the phylogenetic tree, most of the reference strains were clustered in a group, and the similarity values of 16S rDNA sequence were above 96%. However, AI-3, Alcanivorax borkumensis and Halobacillus litoralis were clustered in another group, and the similarity value of 16S rDNA sequences between AI-3 and Alcanivorax borkumensis was 96%, and that of 16S rDNA sequences between AI-3 and Halobacillus litoralis was 99%.