Title: Halobellus clavatus gen. nov., sp. nov. and Halorientalis regularis gen. nov., sp. nov., two new members of the family Halobacteriaceae
Abstract: Four halophilic archaeal strains, designated TNN18 T , TBN12, TNN28 T and TBN19, were isolated from brines sampled from two artificial marine solar salterns in eastern China. Strains TNN18 T and TNN28 T were isolated from the Tainan marine solar saltern, whereas strains TBN12 and TBN19 were from the Taibei marine solar saltern. Colonies of the four strains were red-pigmented and their cells were pleomorphic, motile, Gram-reaction-negative rods. Strains TNN18 T and TBN12 were able to grow at 25–50 °C (optimum 37 °C), in 10–30 % (w/v) NaCl (optimum 15 %), with 0–1.0 M MgCl 2 (optimum 0.05 M) and at pH 5.5–9.0 (optimum pH 7.0–7.5), while strains TNN28 T and TBN19 were able to grow at 20–50 °C (optimum 37 °C), in 15-30 % (w/v) NaCl (optimum 18–20 %), in 0.005–1.0 M MgCl 2 (optimum 0.01–0.3 M) and at pH 6.0–9.0 (optimum pH 7.0–7.5). Cells of these strains lyse in distilled water; minimal NaCl concentrations to prevent cell-lysis are 10 % (w/v) for strains TNN18 T and TBN12 and 12 % (w/v) for strains TNN28 T and TBN19. The major polar lipids of strains TNN18 T and TBN12 were phosphatidylglycerol (PG), phosphatidylglycerol phosphate methyl ester (PGP-Me), phosphatidylglycerol sulfate (PGS) and one major glycolipid (GL1), which was chromatographically identical to sulfated mannosyl glucosyl diether (S-DGD-1). Minor amounts of other lipids (GL0, GL2, GL3 and GL4) were also detectable. The polar lipid profiles of strains TNN28 T and TBN19 contained PG, PGP-Me, GL1, which was chromatographically identical to S-DGD-1, and three to four minor unidentified glycolipids (GL2–GL5). Phylogenetic analyses revealed that strains TNN18 T and TBN12 formed a distinct clade with strains of the closest related species, Haloquadratum walsbyi (91.5–91.8 % 16S rRNA gene sequence similarity) and strains TNN28 T and TBN19 formed a distinct clade with strains of the species Halosimplex carlsbadense (89.9–93.3 % similarity) and two members of the genus Halorhabdus (92.5–93.3 % similarity). The DNA G+C contents of strains TNN18 T , TBN12, TNN28 T and TBN19 were 61.5, 62.4, 61.9 and 61.5 mol%, respectively. DNA–DNA hybridization values between strains TNN18 T and TBN12, and strains TNN28 T and TBN19 were 82.9 % and 88.2 %, respectively. The phenotypic, chemotaxonomic and phylogenetic properties suggest that the four strains represent two novel species of two new genera within the family Halobacteriaceae , for which the names Halobellus clavatus gen. nov., sp. nov. (type strain TNN18 T = CGMCC 1.10118 T = JCM 16424 T ) and Halorientalis regularis gen. nov., sp. nov. (type strain TNN28 T = CGMCC 1.10123 T = JCM 16425 T ) are proposed.