Halophilic archaeal strain YGHS18T was isolated from the Yinggehai marine solar saltern near Shanya city of Hainan Province, China. Cells from the strain were observed to be pleomorphic rods, stained Gram-negative, and formed red-pigmented colonies on solid media. Strain YGHS18T was found to be able to grow at 20–50 °C (optimum 37 °C), with 0.9–4.8 M NaCl (optimum 2.1 M) and at pH 5.5–9.0 (optimum pH 7.0). The cells lysed in distilled water and the minimum NaCl concentration to prevent cell lysis was found to be 0.9 M. The major polar lipids of the strain were identified as phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, phosphatidylglycerol sulfate, glucosyl mannosyl glucosyl diether and a diglycosyl diether (DGD-2). Strain YGHS18T possessed two heterogeneous 16S rRNA genes (rrnA and rrnB) and both were related to those of members of the genera Haloarcula (93.1–96.9 % sequence similarity) and Halomicroarcula (92.7–96.1 % similarity). The rrnA gene (orthologous gene) of strain YGHS18T clustered phylogenetically with members of the genus Halomicroarcula while the rrnB gene formed a paraphyly with members of the genera Halomicroarcula and Haloarcula . The rpoB′ gene of strain YGHS18T was related phylogenetically to species of the genera Halomicroarcula (91.6–92.7 % sequence similarity) and Haloarcula (91.5–92.4 % similarity). EF-2 gene analysis revealed that strain YGHS18T was related phylogenetically to species of the genus Halomicroarcula (92.2–92.9 % sequence similarity) rather than to those of the genus Haloarcula (90.9–91.7 % similarity). The DNA G+C content of strain YGHS18T was determined to be 64.5 mol%. The phenotypic, chemotaxonomic and phylogenetic properties suggested that strain YGHS18T ( = CGMCC 1.12128T = JCM 18369T) represents a novel species of the genus Halomicroarcula , for which the name Halomicroarcula salina sp. nov. is proposed.
Two agar-degrading halophilic archaeal strains, 62ET and 197A, were isolated from commercial salt samples. Cells were non-motile cocci, approximately 1.2–2.0 µm in diameter and stained Gram-negative. Colonies were pink-pigmented. Strain 62ET was able to grow with 24–30 % (w/v) NaCl (optimum, 27 %), at pH 6.5–8.5 (optimum, pH 7.5) and at 22–47 °C (optimum, 42 °C). The 16S rRNA gene sequences of strains 62ET and 197A were identical, and the level of DNA–DNA relatedness between them was 90 and 90 % (reciprocally). The closest relative was Halococcus saccharolyticus JCM 8878T with 99.7 % similarity in 16S rRNA orthologous gene sequences, followed by Halococcus salifodinae JCM 9578T (99.6 %), while similarities with other species of the genus Halococcus were equal to or lower than 95.1 %. The rpoB′ gene tree strongly supported that the two strains were members of the genus Halococcus . Mean DNA–DNA relatedness between strain 62ET and H. saccharolyticus JCM 8878T and H. salifodinae JCM 9578T was 46 and 44 %, respectively. The major polar lipids were archaeol derivatives of phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, derived from both C20C20 and C20C25 archaeol, and sulfated diglycosyl archaeol-1. Several unidentified glycolipids were present. Based on the phenotypic and phylogenetic analyses, the isolates are considered to represent a novel species of the genus Halococcus , for which the name Halococcus agarilyticus sp. nov. is proposed. The type strain is 62ET ( = JCM 19592T = KCTC 4143T).
Three halophilic archaeal strains, MH2-243-1T, MH2-93-1 and MH2-91-1 were isolated from commercial salt samples from Japan, Australia, and Bolivia. Strain MH2-243-1T was able to grow in the presence of 12–30 % (w/v) NaCl (optimum, 18 % NaCl), at pH 4.5–7.0 (optimum, pH 6.0) and at 20–60 °C (optimum, 40 °C). Strains MH2-91-1 and MH2-93-1 grew in slightly different ranges. The orthologous 16S rRNA gene sequences of the three strains were almost identical (99.8–99.9 % similarities), and the closest relative was Salarchaeum japonicum JCM 16327T with 94.2–94.3 % 16S rRNA gene sequence similarities, followed by strains of members of the closely related genera Halobacterium and Halarchaeum . The RNA polymerase subunit B′ gene (rpoB′) sequence also showed the highest similarity (86.6 %) to that of Salarchaeum japonicum JCM 16327T. The DNA G+C contents of strains MH2-243-1T, MH2-93-1 and MH2-91-1 were 68.5, 68.8 and 68.3 mol%, respectively. DNA–DNA relatedness values amongst the three strains were 97–99 %. The polar lipids of the three strains were phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, and at least seven unidentified glycolipids. The polar lipid composition differed from those of Salarchaeum japonicum and species of the genera Halobacterium and Halarchaeum . Based on the phenotypic and phylogenetic analyses, it is proposed that the isolates represent a novel species of a new genus, for which the name Halocalculus aciditolerans gen. nov., sp. nov. is proposed. The type strain of the type species is MH2-243-1T ( = JCM 19596T = KCTC 4149T) isolated from solar salt produced in Japan. MH2-93-1 ( = JCM 19595) and MH2-91-1 ( = JCM 19594) are additional strains of the type species.