Two extremely halophilic archaea, strains RO1-28T and RO1-22, were isolated from a marine solar saltern in Jiangsu, China. Both strains required at least 0.05 M Mg2+ and 1.7 M NaCl for growth. They were able to grow over a pH range of 6.0–8.5 and a temperature range of 25–55 °C, with optimal pH of 7.0 and optimal temperature of 37–40 °C. Based on 16S rRNA gene sequence analysis, strains RO1-28T and RO1-22 were closely related to Haladaptatus paucihalophilus, the single species of the genus Haladaptatus, with similarities of 94.0–95.2 %. The major polar lipids of the two strains were phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, phosphatidylglycerol sulfate and three glycolipids chromatographically identical to the glycolipids of Haladaptatus paucihalophilus JCM 13897T. Both strains RO1-28T and RO1-22 had a DNA G+C content of 54.0 mol% (HPLC). The DNA–DNA hybridization value between the two strains was more than 70 % (92 %) and both strains showed low levels of DNA–DNA relatedness (32 % and 33 %) with Haladaptatus paucihalophilus JCM 13897T. It was concluded that strains RO1-28T and RO1-22 represent a novel species of the genus Haladaptatus, for which the name Haladaptatus litoreus sp. nov. is proposed. The type strain is RO1-28T (=CGMCC 1.7737T =JCM 15771T).
Two isolates of non-alkaliphilic, extremely halophilic archaea, with very similar characteristics, were recovered from a marine solar saltern crystallizer. Cells were pleomorphic, motile and Gram-stain-negative and grew on a limited range of carbon sources, with pyruvate being the best substrate. Optimum growth occurred at 18–20 % (w/v) NaCl, pH 6.0–8.5 and 37–40 °C. Both isolates possessed typical archaeal lipids, and their 16S rRNA gene sequences were 99.8 % identical. Phylogenetic tree reconstructions indicated that they were most closely related to the haloalkaliphile Natronomonas pharaonis (97.5 % similarity to the type strain), but the different phenotypic properties and low DNA–DNA hybridization values between Nmn. pharaonis DSM 2160T and the two isolates suggested that they represent a novel species within the genus Natronomonas. The name Natronomonas moolapensis sp. nov. is proposed for these isolates, with the type strain being 8.8.11T (=JCM 14361T =CECT 7526T =DSM 18674T). An emended description of the genus Natronomonas is also provided.
A novel, extremely halophilic archaeon, D43T, was isolated from traditional salt-fermented seafood in Korea. The cells were Gram-negative-staining and motile. The strain grew at 15–50 °C, 10–30 % (w/v) NaCl and pH 6.0–8.0. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain D43T is affiliated with the family Halobacteriaceae in the domain Archaea and had 95.5 % 16S rRNA gene sequence similarity with Haladaptatus paucihalophilus DX253T. The sequence from strain D43T formed a clade with those from Hap. paucihalophilus regardless of which tree-generating algorithm was used. DNA–DNA hybridization experiments showed 25.8 % relatedness between the isolate and Hap. paucihalophilus KCTC 4006T. Major lipids were phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester and two unidentified glycolipids. The DNA G+C content of the isolate was 56.5 mol%. On the basis of this polyphasic taxonomic study, strain D43T represents a novel species in the genus Haladaptatus, for which the name Haladaptatus cibarius sp. nov. is proposed. The type strain is D43T (=DSM 19505T =JCM 15962T).
Strains 1.15.5T, 2.27.5, 5.24.4 and 6.14.5 were isolated from a solar saltern. They have flattened, rod-shaped cells and are aerobic, extremely halophilic members of the domain Archaea and family Halobacteriaceae. Cells stained Gram-negative and grew optimally in media around neutral pH and containing 20–24 % (w/v) (strains 1.15.5T and 2.27.5) or 22–24 % (w/v) (5.24.4 and 6.14.5) salts. Mg2+ was not required. The DNA G+C contents of these isolates were all close to 58 mol%, and DNA–DNA cross-hybridization showed a mean relatedness of 77 %. Their 16S rRNA gene sequences differed by no more than 1.6 % from each other. Phylogenetic tree reconstructions with other recognized members of the Halobacteriaceae indicated that they formed a distinct clade, with the closest relative being Halorubrum saccharovorum (86.6–87.6 % 16S rRNA gene sequence similarity to the type strain). The only major polar lipid of all four isolates was the sulfated diglycosyl diether lipid S-DGD-1. By phase-contrast microscopy, the long, flattened cells of these strains often displayed a ‘wing-like’ shape. The phenotypic and phylogenetic data support the placement of these isolates into a novel species in a new genus within the Halobacteriaceae, for which we propose the name Halonotius pteroides gen. nov., sp. nov. The type strain of Halonotius pteroides is 1.15.5T (=JCM 14355T =CECT 7525T =DSM 18729T), with the additional reference strains 2.27.5 (=JCM 14356 =DSM 18671), 5.24.4 (=JCM 14357 =DSM 18673) and 6.14.5 (=JCM 14358 =DSM 18692).