title: Methanoculleus taiwanensis sp. nov., a methanogen isolated from deep marine sediment at the deformation front area near Taiwan.
abstract: A mesophilic, hydrogenotrophic methanogen, strain CYW4(T), was isolated from deep-sea sediment obtained by the Ocean Researcher I cruiser, ORI-961, in 2011. The sediment was from the deformation front area offshore of south-western Taiwan. Here, seismic reflections indicated that methane hydrates were abundant. The methanogenic substrates utilized by strain CYW4(T) were formate and H2/CO2, but not acetate, secondary alcohols, methylamines, methanol and ethanol. Cells of strain CYW4(T) were non-motile, irregular cocci and 0.6-1.5 µm in diameter. The S-layer protein had an Mr of 112 000. The optimum growth conditions were at 37 °C, pH 8.1 and 0.08 M NaCl. Growth of the strain was stimulated by acetate. The G+C content of the chromosomal DNA of strain CYW4(T) was 61 mol%. Phylogenetic analysis revealed that strain CYW4(T) was most closely related to Methanoculleus marisnigri JR1(T) (96.82 % 16S rRNA gene sequence similarity). Based on the morphological, phenotypic and phylogenetic characteristics presented here, it is evident that strain CYW4(T) represents a novel species of the genus Methanoculleus, and the name Methanoculleus taiwanensis sp. nov. is proposed. The type strain is CYW4(T) ( = BCRC AR10043(T) = NBRC 110782(T)). The optical density of cultures of strain CYW4(T) dropped abruptly upon entering the stationary growth phase. During this time numerous particles of approximately 50 nm in diameter were observed on and around the cells. This suggests that strain CYW4(T) harbours a lytic virus that is induced in the stationary phase, which is of interest because only a few lytic viruses have been reported in methanogens.
authors.affiliation: Department of Life Sciences, National Chung Hsing University, Taichung, Taiwan.
authors.forename: Chieh-Yin
authors.initials: CY
authors.lastname: Weng
authors.affiliation: Department of Life Sciences, National Chung Hsing University, Taichung, Taiwan.
authors.forename: Sheng-Chung
authors.initials: SC
authors.lastname: Chen
authors.affiliation: Agricultural Biotechnology Center, National Chung Hsing University, Taichung, Taiwan.|Department of Life Sciences, National Chung Hsing University, Taichung, Taiwan.
authors.forename: Mei-Chin
authors.initials: MC
authors.lastname: Lai
authors.affiliation: Department of Life Sciences, National Chung Hsing University, Taichung, Taiwan.
authors.forename: Sue-Yao
authors.initials: SY
authors.lastname: Wu
authors.affiliation: Institute of Oceanography, National Taiwan University, Taipei, Taiwan.
authors.forename: Saulwood
authors.initials: S
authors.lastname: Lin
authors.affiliation: Department of Geosciences, National Taiwan University, Taipei, Taiwan.
authors.forename: Tsanyao F
authors.initials: TF
authors.lastname: Yang
authors.affiliation: Central Geological Survey, MOEA, Taipei, Taiwan.
authors.forename: Po-Chun
authors.initials: PC
authors.lastname: Chen
mesh_terms: D001482:Base Composition; D019641:DNA, Archaeal / Q000235:genetics; D019015:Geologic Sediments / Q000382:microbiology*; D008697:Methane / Q000378:metabolism*; D019638:Methanomicrobiaceae / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D008969:Molecular Sequence Data; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012623:Seawater / Q000382:microbiology; D017422:Sequence Analysis, DNA; D013624:Taiwan
chemical_list: D019641:DNA, Archaeal; D012336:RNA, Ribosomal, 16S; D008697:Methane