Glycine Betaine Monooxygenase, an Unusual Rieske-Type Oxygenase System, Catalyzes the Oxidative -Demethylation of Glycine Betaine in Chromohalobacter salexigens DSM 3043.

Although some bacteria, including DSM 3043, can use glycine betaine (GB) as a sole source of carbon and energy, little information is available about the genes and their encoded proteins involved in the initial step of the GB degradation pathway. In the present study, the results of conserved domain analysis, construction of in-frame deletion mutants, and an functional complementation assay suggested that the open reading frames Csal_1004 and Csal_1005, designated and , respectively, may act as the terminal oxygenase and the ferredoxin reductase genes in a novel Rieske-type oxygenase system to convert GB to dimethylglycine in DSM 3043. To further verify their function, BmoA and BmoB were heterologously overexpressed in , and C nuclear magnetic resonance analysis revealed that dimethylglycine was accumulated in BL21(DE3) expressing BmoAB or BmoA.

Establishment of a markerless gene deletion system in Chromohalobacter salexigens DSM 3043.

Chromohalobacter salexigens DSM 3043 can grow over a wide range of salinity, which makes it as an excellent model organism for understanding the mechanism of prokaryotic osmoregulation. Functional analysis of C. salexigens genes is an essential way to reveal their roles in cellular osmoregulation.

[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.

A Na+/H+ antiporter gene of the moderately halophilic bacterium Halobacillus dabanensis D-8T: cloning and molecular characterization.

A gene encoding a Na(+)/H(+) antiporter was cloned from a chromosomal DNA of Halobacillus dabanensis strain D-8(T) by functional complementation. Its presence enabled the antiporter-deficient Escherichia coli strain KNabc to survive in the presence of 0.2 M NaCl or 5 mM LiCl.

[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.