A halophilic archaeon, strain TBN51T, was isolated from a marine solar saltern in Jiangsu, China. The colonies were red-pigmented and the cells were pleomorphic, motile and Gram-staining-negative. The strain was able to grow at 20–55 °C (optimum 42 °C), in the presence of 1.4–5.1 M NaCl (optimum 2.6 M), with 0–1.0 M MgCl2 (optimum 0.05 M) and at pH 5.5–9.5 (optimum pH 7.0). Cells lysed in distilled water; the minimal NaCl concentration to prevent such lysis was 8 % (w/v). The major polar lipids of strain TBN51T were phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, phosphatidylglycerol sulfate and an unidentified glycolipid. The latter lipid and a minor glycolipid also detected in the novel strain were chromatographically identical to sulfated and non-sulfated mannosyl glucosyl diether, respectively. Analysis revealed that strain TBN51T had three dissimilar 16S rRNA genes. Phylogenetic analysis based on the sequences of these genes indicated that the novel strain was most closely related to Halomicrobium mukohataei JCM 9738T (89.2–94.8 % sequence similarity) and Halomicrobium katesii DSM 19301T (88.8–94.8 %). In similar comparisons of rpoB′ gene sequences, strain TBN51T also appeared most closely related to Hmc. mukohataei JCM 9738T (88.5 % sequence similarity) and Hmc. katesii DSM 19301T (88.1 %). The genomic DNA G+C content of strain TBN51T was 69.1 mol%. The results of DNA–DNA hybridizations indicated that strain TBN51T represented a novel species since it showed relatedness values of only 23 % with Hmc. mukohataei JCM 9738T and 21 % with Hmc. katesii DSM 19301T. It was concluded that strain TBN51T represents a novel species of the genus Halomicrobium , for which the name Halomicrobium zhouii sp. nov. is proposed. The type strain is TBN51T ( = CGMCC 1.10457T = JCM 17095T).
Two halophilic archaea, strains TBN53T and CSW2.24.4T, were characterized to elucidate their taxonomic status. Strain TBN53T was isolated from the Taibei marine solar saltern near Lianyungang city, Jiangsu province, China, whereas strain CSW2.24.4T was isolated from a saltern crystallizer in Victoria, Australia. Cells of the two strains were pleomorphic, stained Gram-negative and produced red-pigmented colonies. Strain TBN53T was able to grow at 25–55 °C (optimum 45 °C), with 1.4–5.1 M NaCl (optimum 2.6–3.9 M NaCl), with 0–1.0 M MgCl2 (optimum 0–0.1 M MgCl2) and at pH 5.5–9.5 (optimum pH 7.0), whereas strain CSW2.24.4T was able to grow at 25–45 °C (optimum 37 °C), with 2.6–5.1 M NaCl (optimum 3.4 M NaCl), with 0.01–0.7 M MgCl2 (optimum 0.05 M MgCl2) and at pH 5.5–9.5 (optimum pH 7.0–7.5). Cells of the two isolates lysed in distilled water. The minimum NaCl concentrations that prevented cell lysis were 8 % (w/v) for strain TBN53T and 12 % (w/v) for strain CSW2.24.4T. The major polar lipids of the two strains were phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester and phosphatidylglycerol sulfate, with two glycolipids chromatographically identical to sulfated mannosyl glucosyl diether and mannosyl glucosyl diether, respectively. Trace amounts of other unidentified lipids were also detected. On the basis of 16S rRNA gene sequence analysis, strains TBN53T and CSW2.24.4T showed 94.1 % similarity to each other and were closely related to Halobellus clavatus TNN18T (95.0 and 94.7 % similarity, respectively). Levels of rpoB′ gene sequence similarity between strains TBN53T and CSW2.24.4T, and between these strains and Halobellus clavatus TNN18T were 88.5, 88.5 and 88.1 %, respectively. The DNA G+C contents of strains TBN53T and CSW2.24.4T were 69.2 and 67.0 mol%, respectively. The level of DNA–DNA relatedness between strain TBN53T and strain CSW2.24.4T was 25 %, and these two strains showed low levels of DNA–DNA relatedness with Halobellus clavatus TNN18T (30 and 29 % relatedness, respectively). Based on these phenotypic, chemotaxonomic and phylogenetic properties, two novel species of the genus Halobellus are proposed to accommodate these two strains, Halobellus limi sp. nov. (type strain TBN53T = CGMCC 1.10331T = JCM 16811T) and Halobellus salinus sp. nov. (type strain CSW2.24.4T = DSM 18730T = CGMCC 1.10710T = JCM 14359T).
A novel red-pigmented halophilic archaeon, strain EB27T, was isolated from Aran-Bidgol salt lake, a hypersaline playa in Iran. Cells of strain EB27T were non-motile and pleomorphic (rods to triangular or disc-shaped). Strain EB27T required at least 2.5 M NaCl and 0.1 M MgCl2 for growth. Optimal growth was achieved at 4 M NaCl and 0.5 M MgCl2. The optimum pH and temperature for growth were pH 7.5 and 40 °C; it was able to grow at pH 6.0–8.0 and 25–50 °C. 16S rRNA gene sequence analysis showed that strain EB27T is a member of the family Halobacteriaceae ; however, levels of 16S rRNA gene sequence similarity were as low as 90.0, 89.3 and 89.1 % to the most closely related haloarchaeal taxa, namely Halalkalicoccus tibetensis DS12T, Halosimplex carlsbadense 2-9-1T and Halorhabdus utahensis AX-2T, respectively. The DNA G+C content of strain EB27T was 61 mol%. Strain EB27T contained phosphatidylglycerol and phosphatidylglycerol phosphate methyl ester, common phospholipids found in haloarchaea, together with two minor phospholipids. The only quinone present was MK-8(II-H2). Physiological, biochemical and phylogenetic differences between strain EB27T and recognized genera of extremely halophilic archaea suggest that this strain represents a novel species in a new genus within the family Halobacteriaceae , for which the name Halovenus aranensis gen. nov., sp. nov. is proposed. The type strain of Halovenus aranensis, the type species of the new genus, is strain EB27T ( = IBRC-M 10015T = CGMCC 1.11001T).
A novel mesophilic, hydrogenotrophic methanogen, designated strain TNRT, was isolated from an anaerobic, propionate-degradation enrichment culture that was originally established from a rice field soil sample from Taiwan. Cells were non-motile rods, 2.0–6.5 µm long by 0.3 µm wide. Filamentous (up to about 100 µm) and coccoid (about 1 µm in diameter) cells were also observed in cultures in the late exponential phase of growth. Strain TNRT grew at 20–40 °C (optimally at 37 °C), at pH 6.5–7.4 (optimally at pH 7.0) and in the presence of 0–25 g NaCl l−1 (optimally at 0 g NaCl l−1). The strain utilized H2/CO2 and formate for growth and produced methane. The G+C content of the genomic DNA was 56.4 mol%. Based on sequences of both the 16S rRNA gene and the methanogen-specific marker gene mcrA, strain TNRT was related most closely to Methanolinea tarda NOBI-1T; levels of sequence similarities were 94.8 and 86.4 %, respectively. The 16S rRNA gene sequence similarity indicates that strain TNRT and M. tarda NOBI-1T represent different species within the same genus. This is supported by shared phenotypic properties, including substrate usage and cell morphology, and differences in growth temperature. Based on these genetic and phenotypic properties, strain TNRT is considered to represent a novel species of the genus Methanolinea , for which the name Methanolinea mesophila sp. nov. is proposed; the type strain is TNRT ( = NBRC 105659T = DSM 23604T). In addition, we also suggest family status for the E1/E2 group within the order Methanomicrobiales , for which the name Methanoregulaceae fam. nov. is proposed; the type genus of family is Methanoregula.