title: Fatty acid, compatible solute and pigment composition of obligately chemolithoautotrophic alkaliphilic sulfur-oxidizing bacteria from soda lakes.
abstract: Salt adaptation in chemolithotrophic alkaliphilic sulfur-oxidizing strains belonging to genera Thioalkalimicrobium and Thioalkalivibrio has been studied by determination of salt-dependent changes in fatty acid and compatible solute composition. In both alkaliphilic groups, represented by the low salt-tolerant Thioalkalimicrobium aerophilum strain AL 3T and the extremely salt-tolerant Thioalkalivibrio versutus strain ALJ 15, unsaturated fatty acids predominate over saturated fatty acids. In strain AL 3T, C18:1, C16:0 and C16:1 were the dominant fatty acids. In strain ALJ 15, the concentrations of C18:1 and C19cyclo were salt-regulated in an inverse proportional relationship, suggesting the stimulation of cyclopropyl-synthetase activity. Squalene has been found in substantial amounts only in strain ALJ 15. Ectoine and glycine betaine were found to be the main osmolytes in Thioalkalimicrobium aerophilum and Thioalkalivibrio versutus, respectively. The production of ectoine and glycine betaine was positively correlated with the salt concentration in the growth medium. A novel type of membrane-bound yellow pigments was uniformly detected in the extremely salt-tolerant strains of Thioalkalivibrio with a backbone consisting of C15-polyene, whose specific concentration correlated with increasing salinity of the growth medium. The results suggest that the mechanisms of haloalkaliphilic adaptation in Thioalkalimicrobium sp. and Thioalkalivibrio sp. involve the production of cyclopropane fatty acids, organic compatible solutes and, possibly specific pigments.
authors.affiliation: Department of Environmental Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC, Delft, The Netherlands.
authors.forename: Horia
authors.initials: H
authors.lastname: Banciu
authors.forename: Dimitry Yu
authors.initials: DY
authors.lastname: Sorokin
authors.forename: W Irene C
authors.initials: WI
authors.lastname: Rijpstra
authors.forename: Jaap S
authors.initials: JS
authors.lastname: Sinninghe Damsté
authors.forename: Erwin A
authors.initials: EA
authors.lastname: Galinski
authors.forename: Shinichi
authors.initials: S
authors.lastname: Takaichi
authors.forename: Gerard
authors.initials: G
authors.lastname: Muyzer
authors.forename: J Gijs
authors.initials: JG
authors.lastname: Kuenen
mesh_terms: D000599:Amino Acids, Diamino / Q000032:analysis*; D005227:Fatty Acids / Q000032:analysis*; D005618:Fresh Water / Q000737:chemistry / Q000382:microbiology*; D020563:Gammaproteobacteria / Q000737:chemistry* / Q000145:classification / Q000378:metabolism / Q000502:physiology; D006863:Hydrogen-Ion Concentration; D010084:Oxidation-Reduction; D010860:Pigments, Biological / Q000032:analysis* / Q000737:chemistry; D012965:Sodium Chloride / Q000494:pharmacology; D013455:Sulfur / Q000378:metabolism*
chemical_list: D000599:Amino Acids, Diamino; D005227:Fatty Acids; D010860:Pigments, Biological; D012965:Sodium Chloride; D013455:Sulfur; C045628:ectoine