Natronoarchaeum rubrum sp. nov., isolated from a marine solar saltern, and emended description of the genus Natronoarchaeum.

A halophilic archaeal strain, GX48(T), was isolated from the Gangxi marine solar saltern near Weihai city in Shandong Province, China. Cells of the strain were rod-shaped, stained Gram-negative and formed red-pigmented colonies. Strain GX48(T) was able to grow at 25-50 °C (optimum 37 °C), in the presence of 1.4-4.8 M NaCl (optimum 2.6 M NaCl), with 0-1.0 M MgCl2 (optimum 0.05 M MgCl2) and at pH 5.5-9.5 (optimum pH 7.0). Cells lysed in distilled water and the minimal NaCl concentration to prevent cell lysis was 8 % (w/v). The major polar lipids of the strain were phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester and two major glycolipids chromatographically identical to those of Natronoarchaeum mannanilyticum YSM-123(T) and Natronoarchaeum philippinense 294-194-5(T). 16S rRNA gene analysis revealed that strain GX48(T) had two dissimilar 16S rRNA genes and both of them were phylogenetically related to those of the two current members of the genus Natronoarchaeum (96.2-98.3 % similarities). The rpoB' gene sequence similarities between strain GX48(T) and Natronoarchaeum mannanilyticum YSM-123(T) and Natronoarchaeum philippinense 294-194-5(T) were 96.0 % and 94.7 %, respectively. The DNA G+C content of strain GX48(T) was 66.2 mol%. Strain GX48(T) showed low DNA-DNA relatedness with the two members of the genus Natronoarchaeum. It was concluded that strain GX48(T) ( = CGMCC 1.10388(T) = JCM 17119(T)) represents a novel species of the genus Natronoarchaeum, for which the name Natronoarchaeum rubrum sp. nov. is proposed. An emended description of the genus Natronoarchaeum is also presented.

Halobellus litoreus sp. nov., a halophilic archaeon isolated from a Chinese marine solar saltern.

Halophilic archaeal strain GX31(T) was isolated from a marine solar saltern of China. The cells of the strain were rod-shaped and lysed in distilled water, stain Gram-negative and formed red-pigmented colonies. It was neutrophilic, and required at least 0.9 M NaCl and 0-1.0 M MgCl2 for growth under the optimum growth temperature of 37 °C. The major polar lipids of the strain were phosphatidylglycerol (PG), PG phosphate methyl ester, PG sulphate, and two major glycolipids chromatographically identical to sulphated mannosyl glucosyl diether (S-DGD-1) and mannosyl glucosyl diether (DGD-1), respectively. Trace amounts of two unidentified lipids were also detected. On the basis of 16S rRNA gene sequence analysis, strain GX31(T) was closely related to the members of Halobellus of the family Halobacteriaceae with similarities of 94.1-98.7 %. Strain GX31(T) showed 89.8-95.4 % of the rpoB' gene similarity to the members of Halobellus. The DNA G+C content of strain GX31(T) was 66.8 mol%. Strain GX31(T) showed low DNA-DNA relatedness with two most related members of the genus Halobellus. The phenotypic, chemotaxonomic and phylogenetic properties suggest that strain GX31(T) represent a novel species of the genus Halobellus, for which the name Halobellus litoreus sp. nov. is proposed. The type strain is GX31(T) (=CGMCC 1.10387(T) = JCM 17118(T)).

Haloplanus salinus sp. nov., an extremely halophilic archaeon from a Chinese marine solar saltern.

Halophilic archaeal strain YGH66(T) was isolated from the Yinggehai marine solar saltern near the Sanya city of Hainan Province, China. Cells were pleomorphic, flat, stained Gram-negative, and produced pink-pigmented colonies. Strain YGH66(T) was able to grow at 20-50 °C (optimum 37 °C), at 0.9-4.8 M NaCl (optimum 3.1 M NaCl), at 0.005-1.0 M MgCl2 (optimum 0.05 M MgCl2), and at pH 6.0-8.0 (optimum pH 7.0). The cells of strain YGH66(T) were lysed in distilled water, and the minimum NaCl concentration that prevented cell lysis was 5 % (w/v). The major polar lipids of the strain were phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, phosphatidylglycerol sulfate, one major glycolipid (GL1) chromatographically identical to sulfated mannosyl glucosyl diether and a minor unidentified lipid (GL2), respectively. On the basis of 16S rRNA gene sequence analysis, strain YGH66(T) was closely related to Haloplanus natans JCM 14081(T), Haloplanus aerogenes TBN37(T), and Haloplanus vescus RO5-8(T) with the similarities of 98.0, 97.6, and 96.9 %, respectively. The rpoB' gene similarity between strain YGH66(T) and the current three members of Haloplanus were 90.4-92.8 %. The DNA G+C content of strain YGH66(T) was 67.2 mol %. The DNA-DNA hybridization values between strain YGH66(T) and three members of Haloplanus, H. natans JCM 14081(T), H. aerogenes TBN37(T), H. vescus RO5-8(T) were 50, 46 and 39 %, respectively. It was concluded that strain YGH66(T) represents a novel species of the genus Haloplanus, for which the name Haloplanus salinus sp. nov. is proposed. The type strain is YGH66(T) (=CGMCC 1.12127(T) = JCM 18368(T)).

Taxonomic study of the genera Halogeometricum and Halosarcina: transfer of Halosarcina limi and Halosarcina pallida to the genus Halogeometricum as Halogeometricum limi comb. nov. and Halogeometricum pallidum comb. nov., respectively.

Members of the haloarchaeal genera Halosarcina and Halogeometricum (family Halobacteriaceae) are closely related to each other and show 96.6-98 % 16S rRNA gene sequence similarity. This is higher than the accepted threshold value (95 %) to separate two genera, and a taxonomic study using a polyphasic approach of all four members of the two genera was conducted to clarify their relationships. Polar lipid profiles indicated that Halogeometricum rufum RO1-4(T), Halosarcina pallida BZ256(T) and Halosarcina limi RO1-6(T) are related more to each other than to Halogeometricum borinquense CGMCC 1.6168(T). Phylogenetic analyses using the sequences of three different genes (16S rRNA gene, rpoB' and EF-2) strongly supported the monophyly of these four species, showing that they formed a distinct clade, separate from the related genera Halopelagius, Halobellus, Haloquadratum, Haloferax and Halogranum. The results indicate that the four species should be assigned to the same genus, and it is proposed that Halosarcina pallida and Halosarcina limi be transferred to the genus Halogeometricum as Halogeometricum pallidum comb. nov. (type strain, BZ256(T) = KCTC 4017(T) = JCM 14848(T)) and Halogeometricum limi comb. nov. (type strain, RO1-6(T) = CGMCC 1.8711(T) = JCM 16054(T)).

Halobellus inordinatus sp. nov., from a marine solar saltern and an inland salt lake of China.

Two halophilic archaeal strains, YC20(T) and XD15, were isolated from a marine solar saltern and an inland salt lake in China. Both had pleomorphic cells that lysed in distilled water, stained Gram-negative and formed red-pigmented colonies. They were neutrophilic, requiring at least 100 g NaCl l(-1) and 0.5-95 g MgCl2 l(-1) for growth at the optimum growth temperature of 37 °C. The major polar lipids of the two strains were phosphatidylglycerol (PG), phosphatidylglycerol phosphate methyl ester (PGP-Me), phosphatidylglycerol sulfate (PGS) and two major glycolipids chromatographically identical to sulfated mannosyl glucosyl diether (S-DGD-1) and mannosyl glucosyl diether (DGD-1), respectively. Trace amounts of two unidentified glycolipids were also detected. The 16S rRNA gene sequences of the two strains were 99.5 % identical and showed 94.0-95.9 % similarity to the most closely related members of the genus Halobellus of the family Halobacteriaceae. The rpoB' gene sequence similarity between strains YC20(T) and XD15 was 98.2 % and these sequences showed 89.6-92.8 % similarity to those of the most closely related members of the genus Halobellus. The DNA G+C contents of strains YC20(T) and XD15 were 65.8 mol% and 65.4 mol%, respectively. The DNA-DNA hybridization value between strain YC20(T) and strain XD15 was 92 %, and the two strains showed low DNA-DNA relatedness to members of the genus Halobellus. The phenotypic, chemotaxonomic and phylogenetic properties suggest that strains YC20(T) and XD15 represent a novel species of the genus Halobellus, for which the name Halobellus inordinatus sp. nov. is proposed. The type strain is YC20(T) ( = CGMCC 1.12120(T) = JCM 18361(T)) and the other strain is XD15 ( = CGMCC 1.12236 = JCM 18648).

Halorubrum rubrum sp. nov., an extremely halophilic archaeon from a Chinese salt lake.

Two halophilic archaeal strains, YC87(T) and YCA11, were isolated from Yuncheng salt lake in Shanxi, China. Cells of the two strains were observed to be pleomorphic rod-shaped, stained Gram-negative and produced red-pigmented colonies. Strain YC87(T) was able to grow at 20-50 °C (optimum 37 °C), at 1.4-4.8 M NaCl (optimum 2.1 M NaCl), at 0.05-1.0 M MgCl2 (optimum 0.3 M MgCl2) and at pH 6.0-9.0 (optimum pH 7.0) while strain YCA11 was able to grow at 20-50 °C (optimum 37 °C), at 2.1-4.8 M NaCl (optimum 3.1 M NaCl), at 0.01-0.7 M MgCl2 (optimum 0.1 M MgCl2) and at pH 6.0-9.0 (optimum pH 7.5). The cells of both isolates were observed to lyse in distilled water. The minimum NaCl concentrations that prevented cell lysis were determined to be 8 % (w/v) for strain YC87(T) and 12 % (w/v) for strain YCA11. The major polar lipids of the two strains were identified as phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, phosphatidylglycerol sulfate and one major glycolipid chromatographically identical to sulfated mannosyl glucosyl diether; another major glycolipid and trace amounts of several unidentified lipids were also detected. The 16S rRNA gene sequences of the two strains were 99.8 % identical, showing 93.2-98.2 % similarity to members of the genus Halorubrum of the family Halobacteriaceae. The rpoB' gene similarity between strains YC87(T) and YCA11 was 99.3 % and showed 87.5-95.2 % similarity to the closest relative members of the genus Halorubrum. The DNA G+C content of strains YC87(T) and YCA11 were determined to be 64.9 and 64.5 mol%, respectively. The DNA-DNA hybridization value between strain YC20(T) and strain YC77 was 87 % and the two strains showed low DNA-DNA relatedness with Halorubrum cibi JCM 15757(T) and Halorubrum aquaticum CGMCC 1.6377(T), the most related members of the genus Halorubrum. The phenotypic, chemotaxonomic and phylogenetic properties suggest that strains YC87(T) and YCA11 represent a novel species of the genus Halorubrum, for which the name Halorubrum rubrum sp. nov. is proposed. The type strain is YC87(T) (=CGMCC 1.12124(T) = JCM 18365(T)).

Halobellus rarus sp. nov., a halophilic archaeon from an inland salt lake of China.

Two halophilic archaeal strains, YC21(T) and YC77, were isolated from an inland salt lake of China. Both have pleomorphic rod-shaped cells that lyse in distilled water, stain Gram-negative and form red-pigmented colonies. They are neutrophilic, require at least 2.1 M NaCl for growth under the optimum growth temperature of 37 °C. The major polar lipids of the two strains were phosphatidylglycerol (PG), phosphatidylglycerol phosphate methyl ester (PGP-Me), phosphatidylglycerol sulfate (PGS), two major glycolipids (GL1 and GL2) chromatographically identical to sulfated mannosyl glucosyl diether (S-DGD-1) and mannosyl glucosyl diether (DGD-1), respectively. Trace amounts of two unidentified lipids (GL0-1 and GL0-2) were also detected. The 16S rRNA gene sequences of the two strains are 99.9 % identical, show 94.0-98.9 % similarity to the closest relative members of Halobellus of the family Halobacteriaceae. The rpoB' gene similarity between strains YC21(T) and YC77 is 99.8 % and show 90.3-95.3 % similarity to the closest relative members of Halobellus. The DNA G+C content of strains YC21(T) and YC77 were 66.1 and 66.2 mol%, respectively. The DNA-DNA hybridization value between strain YC20(T) and strain YC77 was 89 %, and the two strains showed low DNA-DNA relatedness with Halobellus limi TBN53(T), the most related member of Halobellus. The phenotypic, chemotaxonomic and phylogenetic properties suggest that strains YC21(T) and YC77 represent a novel species of the genus Halobellus, for which the name Halobellus rarus sp. nov. is proposed. The type strain is YC21(T) (=CGMCC 1.12121(T) = JCM 18362(T)).

Halohasta litorea gen. nov. sp. nov., and Halohasta litchfieldiae sp. nov., isolated from the Daliang aquaculture farm, China and from Deep Lake, Antarctica, respectively.

Two halophilic archaeal strains, R30(T) and tADL(T), were isolated from an aquaculture farm in Dailing, China, and from Deep Lake, Antarctica, respectively. Both have rod-shaped cells that lyse in distilled water, stain Gram-negative and form red-pigmented colonies. They are neutrophilic, require >120 g/l NaCl and 48-67 g/l MgCl(2) for growth but differ in their optimum growth temperatures (30 °C, tADL(T) vs. 40 °C, R30(T)). The major polar lipids were typical for members of the Archaea but also included a major glycolipid chromatographically identical to sulfated mannosyl glucosyl diether (S-DGD-1). The 16S rRNA gene sequences of the two strains are 97.4 % identical, show most similarity to genes of the family Halobacteriaceae, and cluster together as a distinct clade in phylogenetic tree reconstructions. The rpoB' gene similarity between strains R30(T) and tADL(T) is 92.9 % and less to other halobacteria. Their DNA G + C contents are 62.4-62.9 mol % but DNA-DNA hybridization gives a relatedness of only 44 %. Based on phenotypic, chemotaxonomic and phylogenetic properties, we describe two new species of a novel genus, represented by strain R30(T) (= CGMCC 1.10593(T) = JCM 17270(T)) and strain tADL(T) (= JCM 15066(T) = DSMZ 22187(T)) for which we propose the names Halohasta litorea gen. nov., sp. nov. and Halohasta litchfieldiae sp. nov., respectively.