Hong-Can Liu

Flavobacterium caeni sp. nov., isolated from a sequencing batch reactor for the treatment of malachite green effluents

A Gram-stain-negative, heterotrophic, aerobic, non-spore-forming and non-motile bacterial strain, designated LM5(T), was isolated from activated sludge from a sequencing batch reactor for the treatment of effluents contaminated by malachite green. The taxonomy of strain LM5(T) was studied by phenotypic and phylogenetic methods. Strain LM5(T) formed orange colonies on R2A and YP plates. Cells were rods, 0.4-0.6 microm in diameter and 0.8-1.2 microm in length. Growth occurred at 10-35 degrees C (optimum, 20-25 degrees C), at pH 5.5-9.5 (optimum, pH 6.5-7.5) and in the presence of 0-2 % (w/v) NaCl (optimum, 0.5 %). Oxidase and catalase activities were present. Flexirubin-type pigments were present, but extracellular glycans were absent. MK-6 was the major respiratory quinone. The major fatty acids were iso-C(15 : 0) (28.3 %) and iso-C(17 : 1)omega9c (13.8 %). Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain LM5(T) was a member of the genus Flavobacterium with highest sequence similarity to Flavobacterium soli DS-6(T) (93.2 %) and Flavobacterium lindanitolerans IP-10(T) (92.9 %). Together with F. lindanitolerans IP-10(T), strain LM5(T) formed a distinct lineage in the phylogenetic tree. The DNA G+C content was 52+/-0.6 mol% (HPLC), which is significantly higher than that of other species of the genus Flavobacterium (30-41 mol%). Based on phylogenetic and phenotypic evidence, strain LM5(T) is considered to represent a novel species of the genus Flavobacterium, for which the name Flavobacterium caeni sp. nov. is proposed; the type strain is LM5(T) (=CGMCC 1.7031(T)=NBRC 104239(T)).

Gene cloning and characterization of a cold-adapted β-glucosidase belonging to glycosyl hydrolase family 1 from a psychrotolerant bacterium Micrococcus antarcticus.

The gene bglU encoding a cold-adapted β-glucosidase (BglU) was cloned from Micrococcus antarcticus. Sequence analysis revealed that the bglU contained an open reading frame of 1419 bp and encoded a protein of 472 amino acid residues. Based on its putative catalytic domains, BglU was classified as a member of the glycosyl hydrolase family 1 (GH1). BglU possessed lower arginine content and Arg/(Arg+Lys) ratio than mesophilic GH1 β-glucosidases. Recombinant BglU was purified with Ni2+ affinity chromatography and subjected to enzymatic characterization. SDS-PAGE and native staining showed that it was a monomeric protein with an apparent molecular mass of 48 kDa. BglU was particularly thermolabile since its half-life time was only 30 min at 30°C and it exhibited maximal activity at 25°C and pH 6.5. Recombinant BglU could hydrolyze a wide range of aryl-β-glucosides and β-linked oligosaccharides with highest activity towards cellobiose and then p-nitrophenyl-β-d-glucopyranoside (pNPG). Under the optimal conditions with pNPG as substrate, the K(m) and k(cat) were 7 mmol/L and 7.85 × 103/s, respectively. This is the first report of cloning and characterization of a cold-adapted β-glucosidase belonging to GH1 from a psychrotolerant bacterium.

Nocardioides alpinus sp. nov., a psychrophilic actinomycete isolated from alpine glacier cryoconite.

A gram-positive, non-motile, rod-shaped, psychrophilic actinomycete, designated strain Cr7-14(T), was isolated from alpine glacier cryoconite. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain Cr7-14(T) was related to members of the genus Nocardioides and shared highest 16S rRNA gene sequence similarities with the type strains of Nocardioides furvisabuli (98.6u200a%), Nocardioides ganghwensis (98.2u200a%), Nocardioides oleivorans (98.1u200a%) and Nocardioides exalbidus (97.6u200a%). The predominant cellular fatty acids of strain Cr7-14(T) were C(17u200a:u200a1)ω8c (39.5u200a%) and iso-C(16u200a:u200a0) (32.4u200a%). The major menaquinone was MK-8(H(4)). The diagnostic diamino acid in the cell-wall peptidoglycan was ll-2,6-diaminopimelic acid. The predominant cell-wall sugars were galactose and rhamnose. The polar lipid pattern contained diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine, phosphatidylinositol, four unknown glycolipids and two unknown polar lipids. The genomic DNA G+C content was 71.9 mol%. On the basis of phenotypic characteristics, phylogenetic analysis and DNA-DNA relatedness data, a novel species, Nocardioides alpinus sp. nov., is proposed, with Cr7-14(T) (u200a=u200aDSM 23325(T)u200a=u200aLMG 26053(T)u200a=u200aCGMCC 1.10697(T)) as the type strain.

Luteimonas terricola sp. nov., a psychrophilic bacterium isolated from soil.

Strain BZ92r(T) was isolated from hydrocarbon-contaminated soil. Cells were Gram-negative, aerobic, rod-shaped and cold-adapted (growth at 1-25 degrees C). The major fatty acids were iso-C(15 : 0) (25.6 %), iso-C(17 : 1)omega9c (24.9 %), iso-C(11 : 0) (18.4 %) and iso-C(11 : 0) 3-OH (16.2 %). The predominant ubiquinone was ubiquinone-8. The genomic DNA G+C content was 72.0 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain BZ92r(T) was a member of the genus Luteimonas (94.5-95.2 % 16S rRNA gene sequence similarity). On the basis of phenotypic, chemotaxonomic and phylogenetic distinctiveness, strain BZ92r(T) was considered to represent a novel species of the genus Luteimonas. The name Luteimonas terricola sp. nov. is proposed, with BZ92r(T) (=DSM 22344(T) =CGMCC 1.8985(T)) as the type strain.

Sphingomonas glacialis sp. nov., a psychrophilic bacterium isolated from alpine glacier cryoconite.

A non-motile, rod-shaped, yellow bacterium, designated C16y(T), was isolated from alpine glacier cryoconite. Cells behaved Gram-positively, were aerobic and psychrophilic (good growth at 1-25 °C). Phylogenetic analysis based on 16S rRNA gene sequences showed that strain C16y(T) was related to the genus Sphingomonas and had highest 16S rRNA gene sequence similarity with Sphingomonas oligophenolica JCM 12082(T) (97.6u200a %) and Sphingomonas echinoides DSM 1805(T) (97.2u200a %). DNA-DNA hybridization demonstrated that strain C16y(T) could not be considered as a member of either Sphingomonas oligophenolica or Sphingomonas echinoides. Strain C16y(T) contained Q-10 as the predominant ubiquinone and C₁₈:₁ and C₁₆:₀ were the dominant fatty acids. The polar lipid profile contained phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, sphingoglycolipid, five unidentified glycolipids, two unidentified aminophospholipids and two unidentified lipids. The major polyamines were the triamines sym-homospermidine and spermidine. The G+C content was 67.9 mol%. Combined data from phenotypic, phylogenetic and DNA-DNA relatedness studies demonstrated that strain C16y(T) is a representative of a novel species of the genus Sphingomonas, for which we propose the name Sphingomonas glacialis sp. nov. The type strain is C16y(T) (=DSM 22294(T) =CGMCC 1.8957(T) =CIP 110131(T) [corrected]).

Devosia psychrophila sp. nov. and Devosia glacialis sp. nov., from alpine glacier cryoconite, and an emended description of the genus Devosia

Two psychrophilic strains, Cr7-05(T) and Cr4-44(T), isolated from alpine glacier cryoconite, were characterized by using a polyphasic approach. Both strains were psychrophilic, showing good growth over a temperature range of 1-20 °C. The chemotaxonomic characteristics of these isolates included the presence of C(18:1)ω7c and summed feature 3 (C(16:1)ω7c and/or C(16:1)ω6c) as the major cellular fatty acids, Q-10 as the predominant ubiquinone and diphosphatidylglycerol, phosphatidylglycerol and unknown glycolipids as major polar lipids. The DNA G+C contents of strains Cr7-05(T) and Cr4-44(T) were 61.4 and 63.6 mol%, respectively. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the two isolates belong to the genus Devosia. The 16S rRNA gene sequence similarity between the two strains was 98.6%, but DNA-DNA hybridization indicated 54% relatedness. Strains Cr7-05(T) and Cr4-44(T) exhibited 16S rRNA gene sequence similarity of 94.7-97.2 and 94.9-96.9%, respectively, to the type strains of recognized Devosia species. On the basis of phenotypic characteristics, phylogenetic analysis and DNA-DNA relatedness data, strains Cr7-05(T) and Cr4-44(T) represent two novel species within the genus Devosia, for which the names Devosia psychrophila sp. nov. (type strain Cr7-05(T) =DSM 22950(T) =CGMCC 1.10210(T) =CIP 110130(T)) and Devosia glacialis sp. nov. (type strain Cr4-44(T) =CGMCC 1.10691(T) =LMG 26051(T)) are proposed. An emended description of the genus Devosia is also provided.

Roseibium aquae sp. nov., isolated from a saline lake.

A Gram-staining-negative bacterium, strain DSG-S4-2(T), was isolated from Dasugan Lake, a saline lake (salinity 3.1%, w/v) in Qaidam basin, Qinghai, China and its taxonomic position was determined by using a polyphasic approach. Cells of strain DSG-S4-2(T) were non-spore-forming rods, 0.5-0.8 µm wide and 1.2-3.8 µm long and motile by means of a single polar flagellum. Strain DSG-S4-2(T) was strictly heterotrophic and aerobic, catalase-positive and oxidase-negative. PufLM and coxL genes were present, bacteriochlorophyll a (BChl a) and a carotenoid pigment were produced. Growth was observed in the presence of 0-8.0% (w/v) NaCl (optimum, 1.0-2.0%), at 20-40 °C (optimum, 35 °C) and pH 6.5-10.5 (optimum, pH 7.5-8.0). Strain DSG-S4-2(T) contained Q-10 as the sole respiratory quinone. The polar lipids contained two aminolipids, diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylmonomethylethanolamine, sulphoquinovosyldiacylglyceride, phosphatidylcholine and some unknown phospholipids, like the other members of the genus Roseibium. The predominant fatty acid (>70%) was summed feature 8 (C(18u200a:u200a1)ω7c and/or C(18u200a:u200a1)ω6c). The DNA G+C content was 61.4 mol% (determined from melting temperature). Phylogenetic trees (neighbour-joining, maximum-likelihood and maximum-parsimony) based on 16S rRNA gene sequences showed that strain DSG-S4-2(T) was associated with the members of the genus Roseibium, with highest 16S rRNA gene sequence similarity to Roseibium denhamense OCh 254(T) (96.3%) and Roseibium hamelinense OCh 368(T) (96.3%). Based on the data presented above, it is concluded that strain DSG-S4-2(T) represents a novel species of the genus Roseibium, for which the name Roseibium aquae sp. nov. is proposed. The type strain is DSG-S4-2(T) (u200a=u200aCGMCC 1.12426(T)u200a=u200aJCM 19310(T)).

Massilia yuzhufengensis sp nov, isolated from an ice core

A gram-negative, rod-shaped, aerobic, motile bacterium, strain Y1243-1(T), was isolated from an ice core drilled from Yuzhufeng Glacier, Tibetan Plateau, China. Cells had polar flagella. The novel strain shared 94.7-97.6u200a% 16S rRNA gene sequence similarity with the type strains of species of the genus Massilia. The novel isolate is thus classified in the genus Massilia. The major fatty acids of strain Y1243-1(T) were summed feature 3 (C16u200a:u200a1ω7c and/or iso-C15u200a:u200a0 2-OH) (43.98u200a%), C16u200a:u200a0 (27.86u200a%), C10u200a:u200a0 3-OH (7.10u200a%), C18u200a:u200a0 (6.95u200a%) and C18u200a:u200a1ω7c (5.01u200a%). The predominant isoprenoid quinone was Q-8. The DNA G+C content of strain Y1243-1(T) was 65.7 mol% (Tm). The major polar lipids were phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol. A number of phenotypic characteristics distinguished the novel isolate from the type strains of recognized Massilia species. Furthermore, in DNA-DNA hybridization tests, strain Y1243-1(T) shared 45u200a% relatedness with its closest phylogenetic relative, Massilia consociata CCUG 58010(T). From the genotypic and phenotypic data, it is evident that strain Y1243-1(T) represents a novel species of the genus Massilia, for which the name Massilia yuzhufengensis sp. nov. is proposed. The type strain is Y1243-1(T) (u200a=u200aKACC 16569(T)u200a=u200aCGMCC 1.12041(T)).

Arthrobacter alpinus sp. nov., a psychrophilic bacterium isolated from alpine soil.

An aerobic, Gram-reaction-positive, non-motile, psychrophilic bacterium, designated strain S6-3(T), was isolated from alpine soil. Cells exhibited a rod-coccus growth cycle and produced a yellow pigment. Growth occurred at 1-25 degrees C. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain S6-3(T) was related to members of the genus Arthrobacter, sharing highest sequence similarities with the type strains of Arthrobacter psychrolactophilus (97.9 %) and Arthrobacter stackebrandtii (97.6 %). Strain S6-3(T) had MK-9(H(2)) as the major menaquinone and anteiso-C(15 : 0) as the major fatty acid. The cell-wall peptidoglycan was of type A3alpha l-Lys-l-Thr-Ala(3). The predominant cell-wall sugars were galactose and rhamnose. The genomic DNA G+C content of strain S6-3(T) was 61.9 mol%. On the basis of phenotypic characteristics, phylogenetic analysis and DNA-DNA relatedness data, strain S6-3(T) is considered to represent a novel species of the genus Arthrobacter, for which the name Arthrobacter alpinus sp. nov. is proposed. The type strain is S6-3(T) (=DSM 22274(T) =CGMCC 1.8950(T)).

Massilia eurypsychrophila sp. nov. a facultatively psychrophilic bacteria isolated from ice core

Strain B528-3(T), a Gram-stain-negative, rod-shaped, aerobic, facultatively psychrophilic bacterium with polar flagella, was isolated from an ice core drilled from Muztagh Glacier, Xinjiang, China. The novel isolate was classified into the genus Massilia. The 16S rRNA gene sequence of the novel isolate shares a pairwise similarity of less than 97% with those of all the type strains of the genus Massilia. The major fatty acids of strain B528-3(T) were summed feature 3 (C16:1ω7c and/or iso-C15:0 2-OH) (57.31%), C16:0 (11.46%) and C18:1ω7c (14.72%). The predominant isoprenoid quinone was Q-8. The DNA G + C content was 62.2 mol% (Tm). The major polar lipids of this bacterium were phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol. From the genotypic and phenotypic data, it is evident that strain B528-3(T) represents a novel species of the genus Massilia, for which the name Massilia eurypsychrophila sp. nov. is proposed. The type strain is B528-3(T) (u2009= JCM 30074(T) = CGMCC 1.12828(T)).