An extremely halophilic archaeon, strain PJ61T, was isolated from a subterranean rock salt of Yuanyongjing Salt Mine, Yunnan, China. Colonies were pale, smooth, convex, and round (1.0–2.0 mm in diameter) on nutrient agar plates. Cells of strain PJ61T were spherical or oval , stained Gram-negative, and were non-motile. Optimal growth was observed with 3.4 M NaCl and at 38 °C in aerobic conditions. Mg2+ was required for growth. Phylogenetic analysis based on 16S rRNA gene sequence similarities showed that strain PJ61T belonged to the genus Halorubrum and was closely related to Halorubrum laminariae R60T (98.3 % 16S rRNA gene sequence similarity), Halorubrum salinum GX71T (98.2 %) and other species of the genus Halorubrum (<98 %). Sequence similarities of rpoB′ gene and ef-2 gene between strain PJ61T and the species of the genus Halorubrum also showed that strain PJ61T was closely related to strain Halorubrum salinum GX71T (93.4 % for rpoB′and 94.8 % for ef-2). The DNA–DNA relatedness between strains PJ61T and Halorubrum laminariae R60T was 33±0.5 %, while it was 37±0.4 % for Halorubrum salinum GX71T. The DNA G+C content of strain PJ61T was 65.1 mol%. The major polar lipids of strain PJ61T consisted of phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, phosphatidylglycerol sulfate and sulfated mannosyl glucosyl diether. The phenotypic, chemotaxonomic and phylogenetic properties suggest that strain PJ61T represents a novel species of the genus Halorubrum, for which the name Halorubrum pallidum sp. nov. is proposed. The type strain is PJ61T (=CGMCC 1.15212T =JCM 30955T).
An extremely halophilic archaeal strain YJ-50-S2T was isolated from Yangjiang marine solar saltern, China. Cells were pleomorphic, stained Gram-negative and formed red-pigmented colonies on agar plates. Strain YJ-50-S2T was able to grow at 25–50 °C (optimum 37 °C), with 0.9–4.8 M NaCl (optimum 2.6 M NaCl) and 0–1.0 M MgCl2 (optimum 0.03 M MgCl2), and at pH 5.0–9.5 (optimum pH 7.5). The cells lysed in distilled water and the minimal NaCl concentration to prevent cell lysis was 5 % (w/v). The 16S rRNA gene and rpoB′ gene of strain YJ-50-S2T were phylogenetically related to the corresponding genes of Salinigranum rubrum GX10T (97.0 % and 90.5 % similarities, respectively). The major polar lipids of strainYJ-50-S2T were phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, and two major glycolipids chromatographically identical to sulfated mannosyl glucosyl diether and mannosyl glucosyl diether, respectively. Several unidentified glycolipids were also detected. The DNA G+C content of strain YJ-50-S2T was 65.2 mol%. The phenotypic, chemotaxonomic and phylogenetic properties suggested that strain YJ-50-S2Trepresents a novel species of the genus Salinigranum , for which the name Salinigranum salinum sp. nov. is proposed. The type strain is YJ-50-S2T (=CGMCC 1.12572T=JCM 30033T).
A novel hyperthermophilic, piezophilic, anaerobic archaeon, designated NCB100T, was isolated from a hydrothermal vent flange fragment collected in the Guaymas basin at the hydrothermal vent site named ‘Rebecca’s Roost’ at a depth of 1997 m. Enrichment and isolation were performed at 100 °C under atmospheric pressure. Cells of strain NCB100T were highly motile, irregular cocci with a diameter of ~1 µm. Growth was recorded at temperatures between 70 and 112 °C (optimum 105 °C) and hydrostatic pressures of 0.1–80 MPa (optimum 40–50 MPa). Growth was observed at pH 3.5–8.5 (optimum pH 7) and with 1.5–7 % NaCl (optimum at 2.5–3 %). Strain NCB100T was a strictly anaerobic chemo-organoheterotroph and grew on complex proteinaceous substrates such as yeast extract, peptone and tryptone, as well as on glycogen and starch. Elemental sulfur was required for growth and was reduced to hydrogen sulfide. The fermentation products from complex proteinaceous substrates were CO2 and H2. The G+C content of the genomic DNA was 41.3 %. Phylogenetic analysis of the 16S rRNA gene sequence revealed that strain NCB100T belongs to the genus Pyrococcus , showing 99 % similarity with the other described species of the genus Pyrococcus . On the basis of physiological characteristics, DNA G+C content, similarity level between ribosomal proteins and an average nucleotide identity value of 79 %, strain NCB100T represents a novel species for which the name Pyrococcus kukulkanii sp. nov. is proposed. The type strain is NCB100T (=DSM 101590T=Souchothèque de Bretagne BG1337T).