title: Alkaliphilic heliobacterium Heliorestis baculata sp. nov. and emended description of the genus Heliorestis.
abstract: A rod-shaped heliobacterium motile by peritrichous flagella, designated strain OS-H1, was isolated from a sample of shoreline soil of the soda lake Ostozhe (pH 9.2, total salt content 0.22%) located in the steppe of south-east Siberia. In the first few transfers, the isolate produced heat-resistant endospores. Like other heliobacteria, strain OS-H1 contained bacteriochlorophyll g and lacked intracytoplasmic membranes. The new isolate was a strict anaerobe and photoheterotroph. In the light and in the presence of organic compounds, strain OS-H1 oxidized sulfide to elemental sulfur and polysulfides, but was not capable of photoautotrophic growth. The isolate was an obligate alkaliphile able to grow at pH 8-10.2. The best growth was observed at pH 8.5-9.5, a temperature of 30 degrees C and at 5-10 g sodium carbonate l(-1). Biotin was required as a growth factor. The G+C content of strain OS-H1 was 45.0 mol%. Comparison of the 16S rRNA gene sequence to that of phototrophic bacteria showed strain OS-H1 to group within gram-positive bacteria of the family Heliobacteriaceae with the closest relationship to Heliorestis daurensis (95.6% similarity). Based on physiological, genetic and chemotaxonomic characteristics, the new heliobacterium is described as a new species of the genus Heliorestis, Heliorestis baculata.
authors.affiliation: Institute of Microbiology, Russian Academy of Sciences, Moscow.
authors.forename: I A
authors.initials: IA
authors.lastname: Bryantseva
authors.forename: V M
authors.initials: VM
authors.lastname: Gorlenko
authors.forename: E I
authors.initials: EI
authors.lastname: Kompantseva
authors.forename: T P
authors.initials: TP
authors.lastname: Tourova
authors.forename: B B
authors.initials: BB
authors.lastname: Kuznetsov
authors.forename: G A
authors.initials: GA
authors.lastname: Osipov
mesh_terms: D001419:Bacteria / Q000737:chemistry / Q000145:classification* / Q000235:genetics; D018407:Bacterial Physiological Phenomena; D001429:Bacteriochlorophylls / Q000378:metabolism; D002338:Carotenoids / Q000378:metabolism; D003470:Culture Media; D004275:DNA, Ribosomal / Q000032:analysis / Q000235:genetics; D005227:Fatty Acids / Q000032:analysis; D005618:Fresh Water / Q000382:microbiology; D020459:Genes, rRNA / Q000235:genetics; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D012988:Soil Microbiology
chemical_list: D001429:Bacteriochlorophylls; D003470:Culture Media; D004275:DNA, Ribosomal; D005227:Fatty Acids; D012336:RNA, Ribosomal, 16S; D002338:Carotenoids