title: Influence of salts and pH on growth and activity of a novel facultatively alkaliphilic, extremely salt-tolerant, obligately chemolithoautotrophic sufur-oxidizing Gammaproteobacterium Thioalkalibacter halophilus gen. nov., sp. nov. from South-Western Siberian soda lakes.
abstract: A chemolithoautotrophic sulfur-oxidizing bacterium (SOB) strain ALCO 1 capable of growing at both near-neutral and extremely alkaline pH was isolated from hypersaline soda lakes in S-W Siberia (Altai, Russia). Strain ALCO 1 represents a novel separate branch within the halothiobacilli in the Gammaproteobacteria, which, so far, contained only neutro-halophilic SOB. On the basis of its unique phenotypic properties and distant phylogeny, strain ALCO 1 is proposed as a new genus and species Thioalkalibacter halophilus gen. nov. sp. nov. ALCO 1 was able to grow within a broad range of salinity (0.5-3.5 M of total sodium) with an optimum at around 1 M Na+, and pH (7.2-10.2, pHopt at around 8.5). Na+ was required for sulfur-dependent respiration in ALCO 1. The neutral (NaCl)-grown chemostat culture had a much lower maximum growth rate (micromax), respiratory activity and total cytochrome c content than its alkaline-grown counterpart. The specific concentration of osmolytes (ectoine and glycine-betaine) produced at neutral pH and 3 M NaCl was roughly two times higher than at pH 10 in soda. Altogether, strain ALCO 1 represents an interesting chemolithoautotrophic model organism for comparative investigations of bacterial adaptations to high salinity and pH.
authors.affiliation: Faculty of Biology and Geology, Babes-Bolyai University, 5-7 Clinicilor Street, 400006 Cluj-Napoca, Romania. hbanciu@biochem.ubbcluj.ro
authors.forename: Horia L
authors.initials: HL
authors.lastname: Banciu
authors.forename: Dimitry Y
authors.initials: DY
authors.lastname: Sorokin
authors.forename: Tatyana P
authors.initials: TP
authors.lastname: Tourova
authors.forename: Erwin A
authors.initials: EA
authors.lastname: Galinski
authors.forename: Maria S
authors.initials: MS
authors.lastname: Muntyan
authors.forename: J Gijs
authors.initials: JG
authors.lastname: Kuenen
authors.forename: Gerard
authors.initials: G
authors.lastname: Muyzer
mesh_terms: D000222:Adaptation, Physiological; D000599:Amino Acids, Diamino / Q000378:metabolism; D001426:Bacterial Proteins / Q000378:metabolism; D001622:Betaine / Q000378:metabolism; D002254:Carbonates / Q000378:metabolism; D052837:Chemoautotrophic Growth; D045304:Cytochromes c / Q000378:metabolism; D004269:DNA, Bacterial / Q000032:analysis; D005618:Fresh Water / Q000737:chemistry / Q000382:microbiology*; D020563:Gammaproteobacteria / Q000145:classification / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification / Q000378:metabolism*; D006420:Hemeproteins / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008563:Membrane Lipids / Q000378:metabolism; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D010802:Phylogeny; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S; D054712:Salinity; D012800:Siberia; D012965:Sodium Chloride / Q000378:metabolism; D013457:Sulfur Compounds / Q000378:metabolism*
chemical_list: D000599:Amino Acids, Diamino; D001426:Bacterial Proteins; D002254:Carbonates; D004269:DNA, Bacterial; D006420:Hemeproteins; D008563:Membrane Lipids; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S; D013457:Sulfur Compounds; D001622:Betaine; D012965:Sodium Chloride; C045628:ectoine; D045304:Cytochromes c