An obligately anaerobic spirochaete designated strain JC227T was isolated from the gut of a wood-eating cockroach, Cryptocercus punctulatus (Scudder), from the Rann of Kutch, Gujarat, India. Strain JC227T was Gram-stain-negative, mesophilic, halotolerant and alkaliphilic. Based on 16S rRNA gene sequence analysis, strain JC227T belongs to the genus Spirochaeta, with Spirochaeta sphaeroplastigenens JC133T (99.51 %), S. odontotermitis JC202T (99.30 %), S. alkalica Z-7491T (99.10 %), S. americana (98.54 %) and other members of the genus Spirochaeta ( < 92.7 %) as its closest phylogenetic neighbours. However, DNA–DNA hybridization between strain JC227T and S. sphaeroplastigenens JC133T, S. odontotermitis JC202T, S. alkalica DSM 8900T and S. americana DSM 14872T was 62 ± 2, 63, 58 ± 2 and 48 ± 4 %, respectively. Strain JC227T contained phosphatidylglycerol, diphosphatidylglycerol, an unidentified glycolipid and six unidentified lipids. Summed feature C18 : 1ω7c/C18 : 1ω6c was the predominant cellular fatty acid, with significant proportions of C16 : 0, C14 : 0, C12 : 0, C15 : 1ω6c, C16 : 1ω5c, C16 : 1ω6c/C16 : 1ω7c and C17 : 0 2-OH. The DNA G+C content of strain JC227T was 55.5 mol%. On the basis of physiological, biochemical, chemotaxonomic (including metabolomic) and genomic differences from previously described taxa, strain JC227T can be differentiated from members of the genus Spirochaeta and represents a novel species of a new genus, for which the name Alkalispirochaeta cellulosivorans gen. nov., sp. nov. is proposed. The type strain of Alkalispirochaeta cellulosivorans is JC227T ( = KCTC 15343T = NBRC 110105T). We also propose the reclassification of Spirochaeta sphaeroplastigenens, Spirochaeta odontotermitis, Spirochaeta alkalica and Spirochaeta americana as Alkalispirochaeta sphaeroplastigenens comb. nov. (type strain JC133T = KCTC 15220T = NBRC 109056T), Alkalispirochaeta odontotermitis comb. nov. (type strain JC202T = KCTC 15324T = NBRC 110104T), Alkalispirochaeta alkalica comb. nov. (type strain Z-7491T = DSM 8900T = ATCC 700262T) and Alkalispirochaeta americana comb. nov. (type strain ASpG1T = ATCC BAA-392T = DSM 14872T). The type species of Alkalispirochaeta gen. nov. is Alkalispirochaeta alkalica comb. nov.
An indole-, oxidase- and catalase-negative, non-motile bacterium, strain OGS16T, was isolated from an oral swab of a feral black rat (Rattus rattus) in 2007 in Japan. It stained Gram-negative and had pleomorphic, rod-shaped, non-spore-forming cells. Based on 16S rRNA gene sequence analyses, strain OGS16T was assigned to the genus Streptobacillus, with 16S rRNA gene sequence similarities of 99.3, 99.0, 98.6 and 95.5 % to the type strains of Streptobacillus moniliformis, Streptobacillus notomytis, Streptobacillus felis and Streptobacillus hongkongensis, respectively. Strain OGS16T could also be differentiated clearly from other species of the genus Streptobacillus by rpoB, groEL and recA nucleotide and deduced amino acid sequence analysis. DNA–DNA relatedness as obtained by average nucleotide identity was 89.10 % between strain OGS16T and Streptobacillus moniliformis DSM 12112T. Chemotaxonomic and physiological data for strain OGS16T were congruent with results for other closely related members of the family Leptotrichiaceae, represented by highly similar enzyme profiles and fatty acid patterns. MALDI-TOF MS analysis also proved suitable in discriminating strain OGS16T unequivocally from all currently described taxa of the genus Streptobacillus. On the basis of these data, we propose the novel species Streptobacillus ratti sp. nov., with the type strain OGS16T ( = JCM 31098T = DSM 101843T). The G+C content of the DNA of the type strain is 25.9 mol% and the genome size is 1.50 Mbp.
A pleomorphic, Gram-stain-negative, rod-shaped, indole-, oxidase- and catalase-negative, non-spore-forming, non-motile bacterium was originally isolated from the mandibular lymph node of a guinea pig and deposited as Streptobacillus moniliformis CCUG 39713 in 1998. A second strain, 151011837, was isolated from an identical lesion in a guinea pig in Germany in 2015. On the basis of 16S rRNA gene sequence analyses, these strains displayed highest sequence similarities with Sneathia sanguinegens NTS65407T (93.4 %) and ‘Sneathia amnii’ Sn35 (93.2 %), followed by Streptobacillus moniliformis DSM 12112T (91.3 %), ‘Streptobacillus ratti’ OGS16 (91.2 %), Streptobacillus notomytis AHL370-1T (91.0 %), Streptobacillus hongkongensis HKU33T (90.9 %) and Streptobacillus felis 131000547T (90.9 %). Levels of sequence similarity with all other members of the family Leptotrichiaceae were < 89 %. Results of phylogenetic analyses of strains CCUG 39713T and 151011837, based on gyrB, groEL and recA nucleotide and deduced amino acid sequences, were highly similar, as the topologies of all trees were virtually identical. DNA relatedness values derived from average nucleotide identities calculated for comparisons between strain CCUG 39713T and the type strains of Sneathia sanguinegens and Streptobacillus moniliformis, respectively, were 72.05 and 70.42 %. The genomes of CCUG39713T and 151011837 shared 99.57 % average nucletide identity. The chemotaxonomic and physiological data for strains CCUG 39713T and 151011837 were in congruence with other closely related members of the family Leptotrichiaceae, with highly similar enzyme activities and fatty acid profiles. Matrix-assisted laser desorption ionization time-of-flight MS analysis was capable of clearly discriminating strains CCUG 39713T and 151011837 from all taxa of the family Leptotrichiaceae with validly published names. On the basis of these data, the novel taxon Caviibacter abscessus gen. nov., sp. nov. is proposed. The type strain of Caviibacter abscessus is CCUG 39713T ( = DSM 101949T); 151011837 (DSM 101950) is an additional strain of the species.
A novel autotrophic, thermophilic bacterium, strain TF1T, was isolated from a hot spring in Japan. Cells of strain TF1T were motile, Gram-stain-negative, rod-shaped, 1.0–2.0 μm in length and 0.5–0.6 μm in width. Major components in the cellular fatty acid profile were C16 : 0, C18 : 0 and anteiso-C17 : 0. The temperature range for growth was 40–77 °C, and optimum temperature was 75 °C. The pH range for growth was 5.9–9.5, and the optimum pH was 7.5–8.8. Strain TF1T grew chemolithoautotrophically by disproportionation of sulfur, thiosulfate and sulfite. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the strain belongs to the family Thermodesulfobacteriaceae. The closest cultivated relative was Caldimicrobium rimae DST, with highest 16S rRNA gene sequence similarity of 96 %. The genome of strain TF1T consists of one circular chromosome, with a size of 1.8 Mbp and G+C content of 38.30 mol%. On the basis of its phylogenetic and phenotypic properties, strain TF1T ( = DSM 29380T = NBRC 110713T) is proposed as the type strain of a novel species, Caldimicrobium thiodismutans sp. nov.