Haladaptatus

Abstract: 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).

Abstract: 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).

Abstract: A halophilic archaeon, strain H22T, was isolated from a subterranean salt deposit sampled at Yunnan salt mine, PR China. Colonies of strain H22T were light pink-pigmented. Cells were coccus, non-motile, Gram-stain-negative, and did not lyse in distilled water. The strain was aerobic and grew at 20–55 °C (optimum, 37 °C), in the presence of 10–30 % (w/v) NaCl (20 %) and at pH 6.5–9.0 (pH 7.0). Mg2+ was required for growth (optimum, 0.005 M). Major polar lipids were phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester and sulfated mannosyl-glucosyl-glycerol diether-1. Sequence similarity search based on the multiple 16S rRNA genes (rrnA, rrnB and rrnC) of strain H22T revealed that it was most closely related to species of the genera Haloarchaeobius , Haladaptatus , Halorussus and Halorubellus with relative low sequence similarities (91.9–93.7 %). The strain, however, shared highest rpoB′ gene sequence identities with Halorussus rarus TBN4T (90.8 % rpoB′ gene sequence similarity). Phylogenetic trees based on 16S rRNA and rpoB′ gene sequences revealed a robust lineage of the strain H22T with members of related genera of the family Halobacteriaceae . The DNA G+C content of strain H22T was 62.9 mol%. Genome-based analysis of average nucleotide identity (ANI) and in silico DNA–DNA hybridization (DDH) between strains H22T and its closest relative were equal or lower than 77.7 and 22.4 %, respectively, which were far below the threshold for delineation of a new species. Based on ANI values, in silico DDH, and distinct morphological and physiological differences from the previously described taxa, we suggest that strain H22T represents a novel species of a new genus within the family Halobacteriaceae , for which the name Halomicrococcus hydrotolerans gen. nov., sp. nov. is proposed. The type strain is H22T (=CGMCC 1.16291T=NBRC 113231T).