title: Caldithrix abyssi gen. nov., sp. nov., a nitrate-reducing, thermophilic, anaerobic bacterium isolated from a Mid-Atlantic Ridge hydrothermal vent, represents a novel bacterial lineage.
abstract: A novel, moderately thermophilic, strictly anaerobic, mixotrophic bacterium, designated strain LF13T, was isolated from a deep-sea hydrothermal chimney sample that was collected at a vent site at 14 degrees 45' N, 44 degrees 59' W on the Mid-Atlantic Ridge. Cells were Gram-negative, thin, non-motile rods of variable length. Strain LF13T grew optimally at pH 6.8-7.0 and 60 degrees C with 2.5% (w/v) NaCl. It grew chemo-organoheterotrophically, fermenting proteinaceous substrates, pyruvate and Casamino acids. The strain was able to grow by respiration, utilizing molecular hydrogen (chemolithoheterotrophically) or acetate as electron donors and nitrate as an electron acceptor. Ammonium was formed in the course of denitrification. One-hundred milligrams of yeast extract per litre were required for growth of the strain. The G + C content of the genomic DNA of strain LF13T was 42.5 mol%. Neither 16S rDNA sequence similarity values nor phylogenetic analysis unambiguously related strain LF13T with members of any recognized bacterial phyla. On the basis of 16S rDNA sequence comparisons, and in combination with physiological and morphological traits, a novel genus, Caldithrix, is proposed, with strain LF13T (= DSM 13497T =VKM B-2286T) representing the type species, Caldithrix abyssi.
authors.affiliation: Institute of Microbiology, Russian Academy of Sciences, Prospect 60-letiya Oktyabrya 7/2, 117811 Moscow, Russia.
authors.forename: Margarita L
authors.initials: ML
authors.lastname: Miroshnichenko
authors.affiliation: Institute of Microbiology, Russian Academy of Sciences, Prospect 60-letiya Oktyabrya 7/2, 117811 Moscow, Russia.
authors.forename: Nadezhda A
authors.initials: NA
authors.lastname: Kostrikina
authors.affiliation: Institute of Microbiology, Russian Academy of Sciences, Prospect 60-letiya Oktyabrya 7/2, 117811 Moscow, Russia.
authors.forename: Nikolai A
authors.initials: NA
authors.lastname: Chernyh
authors.affiliation: Institute of Microbiology, Russian Academy of Sciences, Prospect 60-letiya Oktyabrya 7/2, 117811 Moscow, Russia.
authors.forename: Nikolai V
authors.initials: NV
authors.lastname: Pimenov
authors.affiliation: Institute of Microbiology, Russian Academy of Sciences, Prospect 60-letiya Oktyabrya 7/2, 117811 Moscow, Russia.
authors.forename: Tatyana P
authors.initials: TP
authors.lastname: Tourova
authors.affiliation: AN Bach Institute of Biochemistry, Russian Academy of Sciences, Leninsky Prospect 33, 119071 Moscow, Russia.
authors.forename: Alexei N
authors.initials: AN
authors.lastname: Antipov
authors.affiliation: Deutsche Sammlung von Mikroorganismen und Zellkulturen (DSMZ), Mascheroder Weg 1b, D-38124 Braunschweig, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Spring
authors.affiliation: Deutsche Sammlung von Mikroorganismen und Zellkulturen (DSMZ), Mascheroder Weg 1b, D-38124 Braunschweig, Germany.
authors.forename: Erko
authors.initials: E
authors.lastname: Stackebrandt
authors.affiliation: Institute of Microbiology, Russian Academy of Sciences, Prospect 60-letiya Oktyabrya 7/2, 117811 Moscow, Russia.
authors.forename: Elizaveta A
authors.initials: EA
authors.lastname: Bonch-Osmolovskaya
mesh_terms: D001267:Atlantic Ocean; D001482:Base Composition; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics; D016965:Gram-Negative Anaerobic Straight, Curved, and Helical Rods / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D006358:Hot Temperature; D008854:Microscopy, Electron; D008969:Molecular Sequence Data; D009566:Nitrates / Q000378:metabolism; D010084:Oxidation-Reduction; D010802:Phylogeny; D012329:RNA, Bacterial / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012623:Seawater / Q000382:microbiology
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D009566:Nitrates; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S