title: Calorithrix insularis gen. nov., sp. nov., a novel representative of the phylum Calditrichaeota.
abstract: A moderately thermophilic, anaerobic bacterium designated as strain KRT was isolated from a shallow-water submarine hydrothermal vent (Kunashir Island, Southern Kurils, Russia). Cells of strain KRT were thin (0.2-0.3 µm), flexible, motile, Gram-stain-negative rods of variable length. Optimal growth conditions were pH 6.6, 55 °C and 1-3 % (w/v) NaCl. Strain KRT was able to ferment a wide range of proteinaceous substrates, pyruvate, and mono-, di- and polysaccharides. The best growth occurred with proteinaceous compounds. Nitrate significantly stimulated the growth on proteinaceous substrates decreasing H2 formation, ammonium being the main product of nitrate reduction. Strain KRT did not need the presence of a reducing agent in the medium and tolerated the presence of oxygen in the gas phase up to 3 % (v/v). In the presence of nitrate, aerotolerance of isolate KRT was enhanced up to 6-8 % O2 (v/v). Strain KRT was able to grow chemolithoheterotrophically, oxidizing H2 and reducing nitrate to ammonium. Yeast extract (0.05 g l-1) was required for growth. The G+C content of the genomic DNA of strain KRT was 47.3 mol%. 16S rRNA gene sequence analysis placed isolate KRT in the phylum Calditrichaeota where it represented a novel species of a new genus, for which the name Calorithrix insularis gen. nov., sp. nov. is proposed. The type strain of Calorithrix insularis is KRT (=DSM 101605T=VKM B-3022T).
authors.affiliation: Winogradsky Institute of Microbiology, Research Center of Biotechnology of the Russian Academy of Sciences, Moscow 117312, Russia.
authors.forename: Elena I
authors.initials: EI
authors.lastname: Kompantseva
authors.affiliation: Winogradsky Institute of Microbiology, Research Center of Biotechnology of the Russian Academy of Sciences, Moscow 117312, Russia.
authors.forename: Ilya V
authors.initials: IV
authors.lastname: Kublanov
authors.affiliation: Winogradsky Institute of Microbiology, Research Center of Biotechnology of the Russian Academy of Sciences, Moscow 117312, Russia.
authors.forename: Anna A
authors.initials: AA
authors.lastname: Perevalova
authors.affiliation: Winogradsky Institute of Microbiology, Research Center of Biotechnology of the Russian Academy of Sciences, Moscow 117312, Russia.
authors.forename: Nikolay A
authors.initials: NA
authors.lastname: Chernyh
authors.affiliation: Department of Genomic and Proteomic Research, Immanuel Kant Baltic Federal University, Kaliningrad 236041, Russia.
authors.forename: Stepan V
authors.initials: SV
authors.lastname: Toshchakov
authors.affiliation: Winogradsky Institute of Microbiology, Research Center of Biotechnology of the Russian Academy of Sciences, Moscow 117312, Russia.
authors.forename: Yuriy V
authors.initials: YV
authors.lastname: Litti
authors.affiliation: Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences, Moscow 119071, Russia.
authors.forename: Alexey N
authors.initials: AN
authors.lastname: Antipov
authors.affiliation: Winogradsky Institute of Microbiology, Research Center of Biotechnology of the Russian Academy of Sciences, Moscow 117312, Russia.
authors.forename: Elizaveta A
authors.initials: EA
authors.lastname: Bonch-Osmolovskaya
authors.affiliation: Winogradsky Institute of Microbiology, Research Center of Biotechnology of the Russian Academy of Sciences, Moscow 117312, Russia.
authors.forename: Margarita L
authors.initials: ML
authors.lastname: Miroshnichenko
mesh_terms: D001421:Bacteria, Anaerobic / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D015373:Bacterial Typing Techniques; D001482:Base Composition; D004269:DNA, Bacterial / Q000235:genetics; D006090:Gram-Negative Bacteria / Q000235:genetics; D060086:Hydrothermal Vents / Q000382:microbiology*; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012426:Russia; D017422:Sequence Analysis, DNA
chemical_list: D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S