A Gram-negative, aerobic bacterium, designated strain YIM 77755T, was isolated from a geothermally heated soil sample collected at Rehai National Park, Tengchong, Yunnan province, south-west China. Cells of the strain were rod-shaped and colonies were yellow and circular. Growth occurred in 0–1 % (w/v) NaCl, at pH 6.0–8.0 (optimum, pH 7.0) and at 35–55 °C (optimum, 50 °C). The predominant menaquinone was MK-8 and the DNA G+C content was 68.9 mol%. Major fatty acids (>10 %) were anteiso-C15 : 0 and iso-C15 : 0. The polar lipids consisted of an uncharacterized phospholipid and four glycolipids. Based on 16S rRNA gene sequence analysis, strain YIM 77755T formed a cluster with Meiothermus chliarophilus ALT-8T and showed the highest 16S rRNA gene sequence similarity to M. chliarophilus ALT-8T (98.23 %). DNA–DNA relatedness between YIM 77755T and M. chliarophilus DSM 9957T was 54.9±4.1 %. On the basis of the morphological and chemotaxonomic characteristics as well as genotypic data, it is proposed that strain YIM 77755T represents a novel species of the genus Meiothermus , named Meiothermus terrae sp. nov. The type strain is YIM 77755T ( = DSM 26712T = CCTCC AB 2012942T).
A novel, anaerobic filamentous bacterium, strain MO-CFX1T, was isolated from a methanogenic community, which was originally established from subseafloor sediments collected from off the Shimokita Peninsula, Japan. Cells were non-spore-forming, non-motile, Gram-stain-negative and filamentous. The filaments were longer than 10 µm and 130–150 nm in width. Growth of the strain was observed at 10–37 °C (optimum 25–30 °C), at pH 5.5–8.5 (optimum pH 7.0) and in 0–50 g NaCl l−1 (optimum 15 g NaCl l−1). The strain was able to grow with a number of carbohydrates in the presence of yeast extract. The major cellular fatty acids were monounsaturated C18 : 1ω9, C16 : 1ω7 and saturated C18 : 0 and C16 : 0. The intact polar lipids of the strain were dominated by diacylglyceride and sphingolipid core lipid structures with monoglycosidic, mixed phosphomonoglycosidic and fatty-acid-modified monoglycosidic polar head groups. The G+C content of the genomic DNA was 52.4 mol%. Based on the comparative 16S rRNA gene sequence analysis, strain MO-CFX1T was affiliated with the class Anaerolineae within the phylum Chloroflexi and was most closely related to Leptolinea tardivitalis YMTK-2T (sequence identity of 91.0 %). Based on phenotypic and genetic properties of the novel isolate, we propose a novel species representing a new genus Pelolinea submarina gen. nov., sp. nov., for strain MO-CFX1T ( = JCM 17238T, = KCTC 5975T). This is the first formal description, to our knowledge, of an isolate of the phylum Chloroflexi from the deep-sea sedimentary environment.