An extremely haloalkaphilic archaeon, strain T26T, belonging to the genus Halostagnicola , was isolated from sediment of the soda lake Bange in the region of Tibet, China. Phylogenetic analysis based on 16S rRNA gene sequence similarities showed that strain T26T was closely related to Halostagnicola alkaliphila 167-74T (98.4 %), Halostagnicola larsenii XH-48T (97.5 %) and Halostagnicola kamekurae 194-10T (96.8 %). Strain T26T grew optimally in media containing 25 % (w/v) salts, at pH 9.0 and 37 °C in aerobic conditions. Mg2+ was not required for growth. The cells were motile, pleomorphic and Gram-stain-variable. Colonies of this strain were pink pigmented. Hypotonic treatment caused cell lysis. The polar lipids of the isolate consisted of C20C20 and C20C25 derivatives of phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester and minor phospholipids components. Glycolipids were not detected, in contrast to the two neutrophilic species of this genus. The genomic DNA G+C content of strain T26T was 60.1 mol% and DNA–DNA hybridization showed a relatedness of 19 and 17 % with Halostagnicola alkaliphila CECT 7631T and Halostagnicola larsenii CECT 7116T, respectively. The comparison of 16S rRNA gene sequences, detailed phenotypic characterization, polar lipid profile and DNA–DNA hybridization studies revealed that strain T26T belongs to the genus Halostagnicola , and represents a novel species for which the name Halostagnicola bangensis sp. nov. is proposed. The type strain is T26T ( = CECT 8219T = IBRC-M 10759T = JCM 18750T).
A novel hyperthermophilic, anaerobic, archaeon was isolated from a terrestrial hot spring at Uzon Caldera, Kronotsky Nature Reserve, Kamchatka, Russia. The isolate, strain 1860T, grew optimally at 90–95 °C and pH 6.0–7.0. The cells were non-motile straight rods, 1.5–5.0 µm in length, covered with surface-layer lattice. Strain 1860T utilized complex proteinaceous compounds as electron donors and ferrihydrite, Fe(III) citrate, nitrate, thiosulfate, selenite, selenate and arsenate as electron acceptors for growth. The sequence of the 16S rRNA gene of strain 1860T had 97.9–98.7 % similarity with those of members of the genus Pyrobaculum . On the basis of its physiological properties and phylogenetic analyses including in silico genome to genome hybridization, the isolate is considered to represent a novel species, for which the name Pyrobaculum ferrireducens sp. nov. is proposed. The type strain is 1860T ( = DSM 28942T = VKM B-2856T).
The halophilic archaeal strain, YC82T, was isolated from Yuncheng salt lake in Shanxi, PR China. Cells from strain YC82T were Gram-stain negative, pleomorphic rods, which lysed in distilled water and formed light-red colonies on solid media. Strain YC82T grew at 25–50 °C (optimum 37 °C), in 1.4–4.8 M NaCl (optimum 2.0 M), in 0–1.0 M MgCl2 (optimum 0.05 M) and at pH 6.0–9.5 (optimum pH 7.5). The major polar lipids of strain YC82T were phosphatidic acid, phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, phosphatidylglycerol sulfate and three glycolipids, which were chromatographically identical to those of Haloarchaeobius iranensis IBRC-M 10013T and Haloarchaeobius litoreus CGMCC 1.10390T. 16S rRNA gene analysis revealed that strain YC82T had two dissimilar 16S rRNA genes and that it was phylogenetically related to Hab. iranensis IBRC-M 10013T (94.3–99.0 % nucleotide identity) and Hab. litoreus CGMCC 1.10390T (94.1–98.8 % nucleotide identity). The rpoB′ gene similarities between strain YC82T and Hab. iranensis IBRC-M 10013T and Hab. litoreus CGMCC 1.10390T were 96.5 % and 95.7 %, respectively. The DNA G+C content of strain YC82T was 63.7 mol%. Strain YC82T showed low DNA–DNA relatedness with Hab. iranensis IBRC-M 10013T and Hab. litoreus CGMCC 1.10390T. The phenotypic, chemotaxonomic and phylogenetic properties of strain YC82T ( = CGMCC 1.12232T = JCM 18644T) suggest that it represents a novel species of the genus Haloarchaeobius , for which the name Haloarchaeobius salinus sp. nov. is proposed. An emended description of the genus Haloarchaeobius is also presented.
A mesophilic, hydrogenotrophic methanogen, strain CYW4T, 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 CYW4T were formate and H2/CO2, but not acetate, secondary alcohols, methylamines, methanol and ethanol. Cells of strain CYW4T were non-motile, irregular cocci and 0.6–1.5 µm in diameter. The S-layer protein had an M r 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 CYW4T was 61 mol%. Phylogenetic analysis revealed that strain CYW4T was most closely related to Methanoculleus marisnigri JR1T (96.82 % 16S rRNA gene sequence similarity). Based on the morphological, phenotypic and phylogenetic characteristics presented here, it is evident that strain CYW4T represents a novel species of the genus Methanoculleus , and the name Methanoculleus taiwanensis sp. nov. is proposed. The type strain is CYW4T ( = BCRC AR10043T = NBRC 110782T). The optical density of cultures of strain CYW4T 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 CYW4T 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.