Two halophilic archaeal strains, YC20T and XD15, were isolated from a marine solar saltern and an inland salt lake in China. Both had pleomorphic cells that lysed in distilled water, stained Gram-negative and formed red-pigmented colonies. They were neutrophilic, requiring at least 100 g NaCl l−1 and 0.5–95 g MgCl2 l−1 for growth at the optimum growth temperature of 37 °C. The major polar lipids of the two strains were phosphatidylglycerol (PG), phosphatidylglycerol phosphate methyl ester (PGP-Me), phosphatidylglycerol sulfate (PGS) and two major glycolipids chromatographically identical to sulfated mannosyl glucosyl diether (S-DGD-1) and mannosyl glucosyl diether (DGD-1), respectively. Trace amounts of two unidentified glycolipids were also detected. The 16S rRNA gene sequences of the two strains were 99.5 % identical and showed 94.0–95.9 % similarity to the most closely related members of the genus Halobellus of the family Halobacteriaceae . The rpoB′ gene sequence similarity between strains YC20T and XD15 was 98.2 % and these sequences showed 89.6–92.8 % similarity to those of the most closely related members of the genus Halobellus . The DNA G+C contents of strains YC20T and XD15 were 65.8 mol% and 65.4 mol%, respectively. The DNA–DNA hybridization value between strain YC20T and strain XD15 was 92 %, and the two strains showed low DNA–DNA relatedness to members of the genus Halobellus . The phenotypic, chemotaxonomic and phylogenetic properties suggest that strains YC20T and XD15 represent a novel species of the genus Halobellus , for which the name Halobellus inordinatus sp. nov. is proposed. The type strain is YC20T ( = CGMCC 1.12120T = JCM 18361T) and the other strain is XD15 ( = CGMCC 1.12236 = JCM 18648).
A novel haloalkaliphilic archaeon, strain B23T was isolated from the former lake Texcoco in Mexico. The strain was Gram-stain-negative, the cells coccoid to ovoid rods, red pigmented and aerobic. Strain B23T grew in 1.7–4.3 M NaCl, at pH 6.5–9.5 and at 25–45 °C with optimal growth at 2.6–3.4 M NaCl, pH 7.5–8.5 and 37 °C. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain B23T was most closely related to Natronobacterium gregoryi SP2T with 97.3 % sequence similarity. The polar lipids of strain B23T were phosphatidylglycerol and several unidentified phospholipids. The G+C content of the DNA of the strain was 62.5 mol%. Levels of DNA–DNA relatedness between strain B23T and Natronobacterium gregoryi DSM 3393T was 32.3 %. The name Natronobacterium texcoconense sp. nov. is proposed. The type strain is B23T ( = CECT 8068T = JCM 17655T).
Three strictly anaerobic, methanogenic strains JH1T, JH4 and JH8 were isolated from rumen of the Korean native cattle (HanWoo; Bos taurus coreanae) in South Korea. The colonies were circular, opaque, and slightly yellowish. Phylogenetic analyses of 16S rRNA gene and mcrA (encoding α subunit of methyl-coenzyme M reductase) sequences confirmed the affiliation of the novel strains with the Methanobacteriales , and Methanobrevibacter wolinii SHT was the most closely related species. The 16S rRNA gene and mcrA sequence similarities between strains JH1T, JH4 and JH8 and M. wolinii SHT were 96.2 and 89.0 % respectively, and DNA–DNA hybridization of the isolates and M. wolinii DSM 11976T showed a 20 % reassociation. Strain JH1T exhibited 92 % DNA–DNA relatedness with strains JH4 and JH8, and their 16S rRNA gene and mcrA sequences were identical. Cells stained Gram-positive and were non-motile rods, 1.5–1.8 µm long and 0.6 µm wide. The strains were able to use H2/CO2 and formate. The optimum temperature and pH ranges for growth were 37–40 °C and pH 6.5–7.0. The DNA G+C content of strain JH1T was 28 mol%. Based on data from this study using a polyphasic approach, the three strains represent a novel species of genus Methanobrevibacter , for which the name Methanobrevibacter boviskoreani sp. nov. is proposed. The type strain is JH1T ( = KCTC 4102T = JCM 18376T).
Two halophilic moderately acidophilic archaeal strains, MH1-136-2T and MH1-370-1 were isolated from commercial salt samples made from seawater in Japan and Indonesia, respectively. Cells of the two strains were pleomorphic and Gram-stain-negative. Strain MH1-136-2T was pink pigmented, while MH1-370-1 was orange–red pigmented. Strain MH1-136-2T was able to grow at 9–30 % (w/v) NaCl (with optimum, 21 % NaCl, w/v) at pH 4.5–6.2 (optimum, pH 5.2–5.5) and at 18–55 °C (optimum, 45 °C). Strain MH1-370-1 was able to grow at 12–30 % (w/v) NaCl (optimum, 18 %, w/v) at pH 4.2–6.0 (optimum, pH 5.2–5.5) and 20–50 °C (optimum, 45 °C). Strain MH1-136-2T required at least 1 mM Mg2+, while MH1-370-1 required at least 10 mM for growth. Both strains reduced nitrate and nitrite under aerobic conditions. The 16S rRNA gene sequences of strains MH1-136-2T and MH1-370-1 were identical, and the closest relative was Halarchaeum rubridurum MH1-16-3T with 98.3 % similarity. The level of DNA–DNA relatedness between these strains was 90.9 % and 92.4 % (reciprocally), while that between MH1-136-2T and Halarchaeum acidiphilum MH1-52-1T, Halarchaeum salinum MH1-34-1T and Halarchaeum rubridurum MH1-16-3T was 37.7 %, 44.3 % and 41.1 % (each an average), respectively. Based on the phenotypic, genotypic and phylogenetic analyses, it is proposed that the isolates represent a novel species of the genus Halarchaeum , for which the name Halarchaeum nitratireducens sp. nov. is proposed. The type strain is MH1-136-2T ( = JCM 16331T = CECT 7573T) isolated from solar salt produced in Japan.
A methanogenic organism from the domain Archaea , designated strain T10T, was isolated from groundwater sampled from a deep diatomaceous shale formation located in Horonobe, Hokkaido, Japan. The strain utilized H2/CO2 and formate as substrates for methanogenesis. Cells were strictly anaerobic, Gram-negative-staining, flagellated, irregular coccoids, 0.7–1.6 µm in diameter, and occurred singly. The strain grew at 25–45 °C (optimum 37–42 °C), at pH 5.8–8.2 (optimum pH 6.7–6.8) and in the presence of 0–1.3 M NaCl (optimum 0.1–0.2 M NaCl). The G+C content of the genomic DNA was 62.9 mol%. 16S rRNA gene sequencing revealed that, although the strain is a member of the genus Methanoculleus , it clearly differed from all described species of this genus (95.5–98.3 % sequence similarity). Values for DNA–DNA hybridization with type strains of closely related Methanoculleus species were less than 50 %. Phenotypic and phylogenetic features of strain T10T clearly indicate that it represents a novel species of the genus Methanoculleus , for which the name Methanoculleus horonobensis sp. nov. is proposed. The type strain is T10T ( = DSM 21626T = JCM 15517T).