title: Phylogenetic and physiological characterization of a filamentous anoxygenic photoautotrophic bacterium ' Candidatus Chlorothrix halophila' gen. nov., sp. nov., recovered from hypersaline microbial mats.
abstract: We report the phylogenetic and physiological characterization of a mesophilic and halophilic member of the filamentous anoxygenic phototrophic (FAP) bacteria, provisionally named ' Candidatus Chorothrix halophila' gen. nov. sp. nov., that has been maintained in a highly enriched culture in our laboratory for over a decade. Phylogenetic analysis of small-subunit RNA-encoding sequences places ' Candidatus Chlorothrix halophila' in a clade that includes cultivated members of the genera Chloroflexus and Oscillochloris. Physiological studies demonstrated sulfide-dependent photosynthetic uptake of (14)C-labeled bicarbonate. Enzymatic assays for the activity of propionyl-coenzyme A synthase indicated that ' Candidatus Chlorothrix halophila' does not use the 3-hydroxypropionate cycle of Chloroflexus aurantiacus OK-70-fl for autotrophic carbon assimilation. New concepts regarding the taxonomy and phylogeny of FAP bacteria have emerged from this work.
authors.affiliation: Center for Microbial Ecology and Department of Microbiology and Molecular Genetics, Michigan State University, 540 Plant and Soil Sciences Bldg., East Lansing, Michigan 48824-1325, USA. klappenb@msu.edu
authors.forename: Joel A
authors.initials: JA
authors.lastname: Klappenbach
authors.forename: Beverly K
authors.initials: BK
authors.lastname: Pierson
mesh_terms: D018407:Bacterial Physiological Phenomena; D001639:Bicarbonates / Q000378:metabolism; D041862:Chloroflexi / Q000145:classification* / Q000254:growth & development / Q000302:isolation & purification / Q000648:ultrastructure; D041861:Chloroflexus / Q000235:genetics; D003066:Coenzyme A Ligases / Q000502:physiology; D004269:DNA, Bacterial / Q000737:chemistry / Q000302:isolation & purification; D004275:DNA, Ribosomal / Q000737:chemistry / Q000302:isolation & purification; D019015:Geologic Sediments / Q000382:microbiology; D019344:Lactic Acid / Q000031:analogs & derivatives* / Q000378:metabolism; D008969:Molecular Sequence Data; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D013440:Sulfides / Q000378:metabolism; D014871:Water Microbiology
chemical_list: D001639:Bicarbonates; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S; D013440:Sulfides; D019344:Lactic Acid; C031601:hydracrylic acid; D003066:Coenzyme A Ligases; C068072:propionate - CoA ligase