Expansion segments in bacterial and archaeal 5S ribosomal RNAs

The large ribosomal RNAs of eukaryotes frequently contain expansion sequences that add to the size of the rRNAs but do not affect their overall structural layout and are compatible with major ribosomal function as an mRNA translation machine. The expansion of prokaryotic ribosomal RNAs is much less explored. In order to obtain more insight into the structural variability of these conserved molecules, we herein report the results of a comprehensive search for the expansion sequences in prokaryotic 5S rRNAs. Overall, 89 expanded 5S rRNAs of 15 structural types were identified in 15 archaeal and 36 bacterial genomes. Expansion segments ranging in length from 13 to 109 residues were found to be distributed among 17 insertion sites. The strains harboring the expanded 5S rRNAs belong to the bacterial orders Clostridiales, Halanaerobiales, Thermoanaerobacterales, and Alteromonadales as well as the archael order Halobacterales When several copies of a 5S rRNA gene are present in a genome, the expanded versions may coexist with normal 5S rRNA genes. The insertion sequences are typically capable of forming extended helices, which do not seemingly interfere with folding of the conserved core. The expanded 5S rRNAs have largely been overlooked in 5S rRNA databases.

Paraglaciecola marina sp. nov., isolated from marine alga (Sargassum natans (L.) Gaillon)

A novel Gram-stain-negative, straight or curved rod-shaped, non-spore-forming, strictly aerobic, motile bacterium with a single polar flagellum, designated D3211T, was isolated from marine alga collected at the seashore of Yantai, PR China. The organism grew optimally at 24 °C, pH 7.0 and in the presence of 2.0 % (w/v) NaCl. Strain D3211T contained ubiquinone 8 as the major respiratory quinone and C16 : 1  ω7c and/or C16 : 1  ω6c, C16 : 0, iso-C17 : 0 and anteiso-C17 : 1 B and/or iso-C17 : 1 I as the major fatty acids. The predominant polar lipids of strain D3211T were phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol. The DNA G+C content of strain D3211T was 39.4 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that the novel strain was related most closely to Paraglaciecola arctica BSs20135T, Paraglaciecola aestuariivivens JDTF-33T, Paraglaciecola aquimarina KCTC 32108T, Paraglaciecola mesophila DSM 15026T, Paraglaciecola psychrophila JCM 13954T and Paraglaciecola polaris ARK 150T with 97.6, 97.6, 97.5, 97.4, 97.3 and 97.1 % sequence similarities, respectively. Calculated average nucleotide identity and DNA-DNAhybridization values between strain D3211T and its phylogenetically related Paraglaciecola species were in the range 70.2-73.4 % and 19.1-20.4 %, respectively. On the basis of polyphasic analyses, strain D3211T represents a novel species of the genus Paraglaciecola, for which the name Paraglaciecola marina sp. nov. is proposed. The type strain is D3211T (=KCTC 72122T=MCCC 1K03603T).

Microbulbifer harenosus sp. nov., an alginate-degrading bacterium isolated from coastal sand

A Gram-stain-negative, aerobic, rod-shaped bacterium with peritrichous flagella, designated strain HB161719^T, was isolated from coastal sand collected from Tanmen Port in Hainan, PR China. The isolate was found to grow with 2-11 % (w/v) NaCl, at 15-45 °C and pH 6.0-10.0, with an optima of 2-3 % NaCl, 37 °C and pH 7.0, respectively. Chemotaxonomic analysis showed that Q-8 was detected as the sole respiratory quinone and that iso-C_15 : 0 and summed features 3, 8 and 9 were the major cellular fatty acids. The G+C content of the genomic DNA was 58.2 mol%. Analysis of the 16S rRNA gene sequence of the strain showed an affiliation with the genus Microbulbifer, sharing 98.7, 98.4, 97.8 and 97.8 % sequence similarities to the closest relatives of Microbulbifer okinawensis ABABA23^T, Microbulbifer pacificus SPO729^T, Microbulbifer taiwanensis CC-LN1-12^T and Microbulbifer gwangyangensis GY2^T, respectively. Low DNA-DNA hybridization values showed that it formed a distinct genomic species. The combined phenotypic and molecular features supported that strain HB161719^T represents a novel species of the genus Microbulbifer, for which the name Microbulbifer harenosus sp. nov. is proposed. The type strain is HB161719^T (=CGMCC 1.13584^T=JCM 32688^T).

Emended description of the family Chromatiaceae, phylogenetic analyses of the genera Alishewanella, Rheinheimera and Arsukibacterium, transfer of Rheinheimera longhuensis LH2-2T to the genus Alishewanella and description of Alishewanella alkalitolerans sp. nov. from Lonar Lake, India

Phylogenetic analyses were performed for members of the family Chromatiaceae, signature nucleotides deduced and the genus Alishewanella transferred to Chromatiaceae. Phylogenetic analyses were executed for the genera Alishewanella, Arsukibacterium and Rheinheimera and the genus Rheinheimera is proposed to be split, with the creation of the Pararheinheimera gen. nov. Furthermore, the species Rheinheimera longhuensis, is transferred to the genus Alishewanella as Alishewanella longhuensis comb. nov. Besides, the genera Alishewanella and Rheinheimera are also emended. Strain LNK-7.1^T was isolated from a water sample from the Lonar Lake, India. Cells were Gram-negative, motile rods, positive for catalase, oxidase, phosphatase, contained C_16:0, C_17:1ω8c, summed feature3 (C_16:1ω6c and/or C_16:1ω7c) and summed feature 8 (C_18:1ω7c) as major fatty acids, PE and PG as the major lipids and Q-8 as the sole respiratory quinone. Phylogenetic analyses using NJ, ME, ML and Maximum parsimony, based on 16S rRNA gene sequences, identified Alishewanella tabrizica RCRI4^T as the closely related species of strain LNK-7.1^T with a 16S rRNA gene sequence similarity of 98.13%. The DNA-DNA similarity between LNK-7.1^T and the closely related species (A. tabrizica) was only 12.0% and, therefore, strain LNK-7.1^T was identified as a novel species of the genus Alishewanella with the proposed name Alishewanella alkalitolerans sp. nov. In addition phenotypic characteristics confirmed the species status to strain LNK-7.1^T. The type strain of A. alkalitolerans is LNK-7.1^T (LMG 29592^T = KCTC 52279^T), isolated from a water sample collected from the Lonar lake, India.

Planctobacterium marinum gen. nov., sp. nov., a new member of the family Alteromonadaceae isolated from seawater

A bacterial strain designated K7T was isolated from the South China Sea and characterized using a polyphasic taxonomic approach. Cells of strain K7T were Gram-stain-negative, aerobic, poly-β-hydroxybutyrate-accumulating, motile by means of a monopolar flagellum, non-spore forming rods surrounded by a thick capsule and forming yellow colonies. Growth occurred at 4-35 °C (optimum, 25-30 °C), at pH 5.0-9.0 (optimum, pH 7.0) and with 0.5-10 % (w/v) NaCl [optimum, 1-4 % (w/v)]. The predominant fatty acids were summed feature 3 (comprising C16 : 1ω7c and/or C16 : 1ω6c), C16 : 0 and C18 : 1ω7c. The major isoprenoid quinone was Q-8 and the DNA G+C content was 46.5 mol%. The polar lipid profile consisted of a mixture of phosphatidylethanolamine, phosphatidylglycerol, phosphatidylmonomethylethanolamine, one uncharacterized phospholipid, two uncharacterized aminophospholipids and five uncharacterized lipids. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain K7T formed a distinct lineage with respect to closely related genera in the family Alteromonadaceae. Strain K7T was most closely related to Aestuariibacter, Aliiglaciecola, Paraglaciecola and Glaciecola, and the levels of 16S rRNA gene sequence similarity with respect to the type species of related genera were less than 95 %. On the basis of the genotypic and phenotypic data, strain K7T represents a novel species of a new genus of the family Alteromonadaceae, for which the name Planctobacterium marinum gen. nov., sp. nov. is proposed. The type strain of Planctobacterium marinum is K7T (=BCRC 80901T=LMG 28835T=KCTC 42657T).

Tamilnaduibacter salinus gen. nov., sp. nov., a halotolerant gammaproteobacterium within the family Alteromonadaceae, isolated from a salt pan in Tamilnadu, India

Two novel Gram-stain-negative, slow-growing, halotolerant strains with rod-shaped cells, designated as strains Mi-7T and Mi-8, which formed pin-point colonies on halophilic media were isolated during a study into the microbial diversity of a salt pan in the state of Tamilnadu, India. Both the strains had an obligate requirement for 1 % (w/v) NaCl for growth and were halotolerant, growing at NaCl concentrations of up to 20 % (w/v) in media. The strains, however, showed an inability to utilize the majority of substrates tested as sole carbon sources for growth and in fermentation reactions. Molecular phylogenetic analyses, based on 16S rRNA gene sequence revealed their closest phylogenetic neighbours to be members of the genus Marinobacter, with whom they showed the highest sequence similarity of 93.6 % and even less with the type strain of the type species, Marinobacter hydrocarbonoclasticus DSM 8798T (91.1 %). Similarities with other genera within the family Alteromonadaceae were below 91.0 %. However, the two strains were very closely related to each other with 99.9 % sequence similarity, and DNA–DNA hybridization analyses confirmed their placement in the same species. The DNA G+C content of both strains was 65 mol%. Using the polyphasic taxonomic data obtained from this study, strains Mi-7T and Mi-8 represent two strains of the same species of a novel genus for which the name Tamilnaduibacter salinus gen. nov., sp. nov., is proposed; the type strain of the novel species is Mi-7T ( = MTCC 12009T = DSM 28688T).

Agaribacter marinus gen. nov., sp. nov., an agar-degrading bacterium from surface seawater

A Gram-stain-negative, motile, mesophilic, aerobic, rod-shaped bacterium, strain 8-8(T), was isolated from surface seawater at Muroto, Kochi, Japan. The strain exhibited agar-degrading activity. Phylogenetic analyses based on 16S rRNA gene sequences showed that the strain fell within the family Alteromonadaceae and clustered distantly with members of the genus Glaciecola (≤ 94.0% similarity). The DNA G+C content was 41.8 mol%. The major fatty acids were C16 : 1ω7c and/or iso-C15 : 0 2-OH, C16 : 0 and C18 : 1ω7c and the major hydroxy fatty acid was C12 : 0 3-OH. The major polar lipids were phosphatidylethanolamine, phosphatidylglycerol and an unidentified polar lipid; lysophosphatidylethanolamine and unidentified polar lipids were found as minor components. The major quinone was Q-8. On the basis of phenotypic, genotypic and chemotaxonomic data, strain 8-8(T) represents a novel species of a new genus, for which the name Agaribacter marinus gen. nov., sp. nov. is proposed. The type strain of Agaribacter marinus is 8-8(T) ( = NBRC 110023(T) = LMG 28167(T)).

Ca-Mg kutnahorite and struvite production by Idiomarina strains at modern seawater salinities

The production of Mg-rich carbonates by Idiomarina bacteria at modern seawater salinities has been investigated. With this objective, four strains: Idiomarina abyssalis (strain ATCC BAA-312), Idiomarina baltica (strain DSM 15154), Idiomarina loihiensis (strains DSM 15497 and MAH1) were used. The strain I. loihiensis MAH1 is a new isolate, identified in the scope of this work. The four moderately halophilic strains precipitated struvite (NH4MgPO4 x 6H2O) crystals that appear encased by small Ca-Mg kutnahorite [CaMg(CO3)2] spheres and dumbbells, which are also regularly distributed in the bacterial colonies. The proportion of Ca-Mg kutnahorite produced by the bacteria assayed ranged from 50% to 20%, and I. abyssalis also produced monohydrocalcite. All precipitated minerals appeared to be related to the bacterial metabolism and, consequently, can be considered biologically induced. Amino acid metabolism resulted in a release of ammonia and CO2 that increase the pH and CO(3)(2-) concentration of the culture medium, creating an alkaline environment that favoured carbonate and struvite precipitation. This precipitation may be also related to heterogeneous nucleation on negatively charged points of biological structures. Because the nature of the organic matrix determines which ion is preferentially adsorbed and, consequently, which mineral phase is formed, the uniquely high content in odd-iso-branched fatty acids of the Idiomarina suggests that their particular membrane characteristics could induce Ca-Mg kutnahorite production. The Ca-Mg kutnahorite, a mineral with a dolomite-ordered structure, production at seawater salinities is noticeable. To date, such precipitation in laboratory cultures, has only been described in hypersaline conditions. It has also been the first time that biomineralization processes have been related to Idiomarina bacteria.

Microbulbifer celer sp. nov., isolated from a marine solar saltern of the Yellow Sea in Korea

A Gram-negative, non-motile, rod-shaped, Microbulbifer-like bacterial strain, ISL-39T, was isolated from a marine solar saltern of the Yellow Sea in Korea and was subjected to a polyphasic taxonomic investigation. Strain ISL-39T grew optimally at pH 7.0–8.0 and 37 °C. It contained Q-8 as the predominant ubiquinone and iso-C15 : 0, C16 : 0 and iso-C17 : 0 as the major fatty acids. The DNA G+C content was 57.7 mol%. A phylogenetic analysis based on 16S rRNA gene sequences showed that strain ISL-39T belonged to the genus Microbulbifer. Strain ISL-39T exhibited 16S rRNA gene sequence similarity values of 94.7–97.5 % with respect to the type strains of four recognized Microbulbifer species. DNA–DNA relatedness data and the differential phenotypic properties and phylogenetic distinctiveness of ISL-39T make this strain distinguishable from the recognized Microbulbifer species. On the basis of the phenotypic, phylogenetic and genetic data, strain ISL-39T represents a novel species of the genus Microbulbifer, for which the name Microbulbifer celer sp. nov. is proposed. The type strain is ISL-39T (=KCTC 12973T=CCUG 54356T).

Marinobacterium litorale sp. nov. in the order Oceanospirillales

A bacterial strain named IMCC1877T was obtained from surface seawater collected near the coast of Deokjeok island (Yellow Sea), using a standard dilution-plating method. The strain was Gram-negative, chemoheterotrophic and facultatively anaerobic, requiring NaCl, and cells were motile rods with a single polar flagellum. Colonies on marine agar were very small (average diameter 0.1 mm). Based on 16S rRNA gene sequences, the most closely related species to strain IMCC1877T was Marinobacterium stanieri (93.7 % sequence similarity to the type strain). Phylogenetic analyses based on 16S rRNA gene sequences showed that this marine isolate belonged to the order Oceanospirillales and formed an independent phyletic line within the clade forming the genus Marinobacterium. The DNA G+C content of the strain was 60.7 mol% and the predominant constituents of the cellular fatty acids were C18 : 1 ω7c (36.6 %), C16 : 1 ω7c and/or iso-C15 : 0 2-OH (26.7 %) and C16 : 0 (24.3 %). Based on the taxonomic data, only a distant relationship could be established between strain IMCC1877T and other Marinobacterium species; the strain therefore represents a novel species of the genus Marinobacterium, for which the name Marinobacterium litorale sp. nov. is proposed. The type strain is IMCC1877T (=KCTC 12756T=LMG 23872T).

Glaciecola agarilytica sp. nov., an agar-digesting marine bacterium from the East Sea, Korea

A taxonomic study was carried out on an isolate, strain NO2T, from marine sediment collected from the East Sea, Korea. Comparative 16S rRNA gene sequence studies showed that this strain belonged to the Gammaproteobacteria and was most closely related to Glaciecola mesophila KMM 241T and Glaciecola polaris LMG 21857T (98.6 and 98.0 % 16S rRNA gene sequence similarity, respectively). The isolate was Gram-negative, aerobic and slightly halophilic and grew in 2–8 % NaCl and at 7–30 °C. Strain NO2T shared some physiological and biochemical properties with G. mesophila KMM 241T and G. polaris LMG 21857T. The G+C content of the genomic DNA of strain NO2T was 45 mol%. Strain NO2T possessed C16 : 0, summed feature 4 (C16 : 1 ω7c and/or iso-C15 : 0 2-OH) and summed feature 7 (C18 : 1 ω9c/ω12t/ω7c) as the major cellular fatty acids. DNA–DNA relatedness data indicated that strain NO2T represents a distinct species that is separate from G. mesophila and G. polaris. On the basis of polyphasic evidence, it is proposed that strain NO2T (=KCTC 12755T=LMG 23762T) represents the type strain of a novel species, Glaciecola agarilytica sp. nov.

Predominance of Roseobacter, Sulfitobacter, Glaciecola and Psychrobacter in seawater collected off Ushuaia, Argentina, Sub-Antarctica

Bacterial diversity in sub-Antarctic seawater, collected off Ushuaia, Argentina, was examined using a culture independent approach. The composition of the 16S rRNA gene libraries from seawater and seawater contaminated with the water soluble fraction of crude oil was statistically different (P value 0.001). In both libraries, clones representing the Alphaproteobacteria, Gammaproteobacteria, the Cytophaga-Flavobacterium-Bacteroidetes group and unculturable bacteria were dominant. Clones associated with the genera Roseobacter, Sulfitobacter, Staleya, Glaciecola, Colwellia, Marinomonas, Cytophaga and Cellulophaga were common to both the libraries. However, clones associated with Psychrobacter, Arcobacter, Formosa algae, Polaribacter, Ulvibacter and Tenacibaculum were found only in seawater contaminated with hydrocarbons (Table 1). Further, the percentage of clones of Roseobacter, Sulfitobacter and Glaceicola was high in seawater (43%, 90% and 12% respectively) compared to seawater contaminated with hydrocarbons (35%, 4% and 9% respectively). One of the clones F2C63 showed 100% similarity with Marinomonas ushuaiensis a bacterium identified by us from the same site.

Marinobacterium halophilum sp. nov., a marine bacterium isolated from the Yellow Sea

A moderately halophilic, aerobic, Gram-negative bacterium was isolated from a tidal flat area of Dae-Chun, Chung-Nam, Korea. The strain, designated mano11T, comprised rod-shaped cells that were motile by means of polar flagella. It grew with 3–12 % NaCl and at 4–37 °C and pH 5.3–9.3. The predominant menaquinone present in this strain was MK-7 and diaminopimelic acid was not found in the cell-wall peptidoglycan. A phylogenetic analysis based on 16S rRNA gene sequences showed that strain mano11T belongs to the genus Marinobacterium. Strain mano11T exhibited 92.8–98.3 % 16S rRNA gene sequence similarity when compared with the type strains of three other species of the genus Marinobacterium. DNA–DNA hybridization between strain mano11T and Marinobacterium georgiense DSM 11526T, its closest relative in terms of 16S rRNA gene sequence similarity, was 13 %. On the basis of the phenotypic, genetic and phylogenetic data, strain mano11T represents a novel species of the genus Marinobacterium, for which the name Marinobacterium halophilum sp. nov. is proposed. The type strain is mano11T (=KCTC 12240T=DSM 17586T).

Glaciecola psychrophila sp. nov., a novel psychrophilic bacterium isolated from the Arctic

A novel bacterial strain, designated 170T, was collected from high latitude Arctic locations (77° 30′ N to approximately 81° 12′ N), including the Canadian Basin and Greenland Sea. Phylogenetic analysis based on 16S rRNA gene sequence comparisons showed that strain 170T was related to members of the genus Glaciecola and had the highest 16S rRNA gene sequence similarity to Glaciecola mesophila. Cells were Gram-negative, psychrophilic, motile rods. The temperature range for growth was 4–15 °C, with optimum growth at 12 °C and at approximately pH 6.0–9.0. Strain 170T contained C16 : 1 ω7c, C16 : 0, C12 : 1 3-OH and C18 : 1 ω7c as major fatty acids. The genomic DNA G+C content was 42.9 mol%. On the basis of phenotypic characterization, phylogenetic analysis and DNA–DNA relatedness data, strain 170T is considered to represent a novel species of the genus Glaciecola, for which the name Glaciecola psychrophila is proposed. The type strain is 170T (=CGMCC 1.6130T=JCM 13954T).

Glaciecola chathamensis sp. nov., a novel marine polysaccharide-producing bacterium

Two novel exopolysaccharide-producing bacteria, strains S18K6T and S18K5, were isolated from Pacific Ocean sediment. The isolates were Gram-negative, motile, strictly aerobic chemoheterotrophic bacteria. The DNA G+C contents of strains S18K6T and S18K5 were 44.8 and 46.3 mol%, respectively. DNA–DNA relatedness between the two strains was 70 %. Major fatty acids were hexadecanoic acid (C16 : 0), hexadecenoic acid (C16 : 1 ω7c) and octadecenoic acid (C18 : 1 ω7c). 16S rRNA gene sequence, chemotaxonomic and morphological data indicated that these strains clearly belonged to the genus Glaciecola. Based on phenotypic properties and DNA–DNA hybridization data, strains S18K6T and S18K5 are considered to represent a novel species of the genus Glaciecola, for which the name Glaciecola chathamensis sp. nov. is proposed. The type strain is S18K6T (=JCM 13645T=NCIMB 14146T).

Marine bacteria associated with the Korean brown alga, Undaria pinnatifida

Several marine bacterial strains were isolated from Undaria pinnatifida (Miyok in Korean). Sixty-six strains were isolated on R2A agar media at 10 degrees and identified by a phylogenetic analysis of the 16S rRNA gene sequences. They were grouped into 10 different sequence types based on the initial sequence analysis of the 5' domain of the gene (approximately 500 bp). Full sequences of 16S rRNA gene were obtained from one strain in each sequence type and the species-affiliation was determined using phylogenetic and sequence similarity analyses. The results of the analyses indicated that they were closely related to Psychrobacter aquimaris, P. celer, P. nivimaris, P. pulmonis, Psychromonas arctica or Bacillus psychrodurans. These bacteria are marine or psychrotrophic bacteria. Because the sporophytes of U.pinnatifida are cultured on the costal area during winter, the U. pinnatifida-associated bacteria appeared to grow at low temperatures. U. pinnatifida sporophytes can be a good source for the isolation of psychrotrophic bacteria.

Idiomarina homiensis sp. nov., isolated from seashore sand in Korea

A halophilic, aerobic bacterium, designated PO-M2(T), was isolated from seashore sand, from Pohang, Korea and characterized on the basis of physiological and biochemical features. Phylogenetic analysis of 16S rRNA gene sequences revealed a clear affiliation of the novel strain with members of the genus Idiomarina. Sequence similarities between strain PO-M2(T) and the type strains of species belonging to the genus Idiomarina ranged from 94.3 to 95.5 %. Cells of strain PO-M2(T) were straight or slightly curved rods and formed light-yellow colonies on marine agar medium. The major isoprenoid quinone was ubiquinone (Q-8) and the predominant cellular fatty acids were C(15 : 0) iso (19.3 %), C(17 : 1)omega9c iso (11.9 %), C(17 : 0) iso (10.9 %), C(18 : 1)omega7c (10.4 %), C(16 : 0) (9.0 %) and C(16 : 1)omega7c and/or C(15 : 0) iso 2-OH (7.2 %). The G+C content of the DNA was 45.1 mol%. Based on physiological, biochemical and chemotaxonomic traits and comparative 16S rRNA gene sequence analysis, it is demonstrated that the isolate represents a novel species of the genus Idiomarina, for which the name Idiomarina homiensis sp. nov. is proposed. The type strain is PO-M2(T) (=KACC 11514(T)=DSM 17923(T)).

Discovery of a marine bacterium producing 4-hydroxybenzoate and its alkyl esters, parabens

Chemically synthesized 4-hydroxybenzoate (4HBA) is widely used in the chemical and electrical industries as a material for producing polymers such as those of the liquid crystal type. Its alkyl esters, called parabens, have been the most widely used preservatives by the food and cosmetic industries. We report here for the first time a microorganism, a marine bacterium, which biosynthesizes these petrochemical products. The marine bacterial strain, A4B-17, which was found to belong to the genus Microbulbifer on the basis of its rRNA and gyrB sequences, was isolated from an ascidian in the coastal waters of Palau. Strain A4B-17 was, surprisingly, found to produce 10 mg/liter of 4HBA, together with its butyl (24 mg/liter), heptyl (0.4 mg/liter), and nonyl (6 mg/liter) esters. We therefore characterized 23 other marine bacteria belonging to the genus Microbulbifer, which our institute had previously isolated from various marine environments, and found that these bacteria also produced 4HBA, although with low production levels (less than one-fifth of that produced by A4B-17). We also show that the alkyl esters of 4HBA produced by strain A4B-17 were effective in preventing the growth of yeasts, molds, and gram-positive bacteria.

Glaciecola nitratireducens sp. nov., isolated from seawater

A marine bacterial strain, FR1064T, was isolated from a surface seawater sample collected off Jeju Island, South Korea. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the isolate belonged to the Gammaproteobacteria and was related to the genus Glaciecola with 97.6 % sequence similarity to Glaciecola pallidula, its nearest phylogenetic neighbour. DNA–DNA relatedness between strain FR1064T and G. pallidula ACAM 615T was 55 %. Cells of the novel isolate were Gram-negative, aerobic, rod-shaped, motile and halophilic, with an optimum sea salts concentration of 4–7 %. The major fatty acids were straight-chain saturated (C16 : 0), summed feature 3 and monounsaturated fatty acid C18 : 1. The DNA G+C content was 44 mol%. Several phenotypic characteristics differentiated the novel isolate from all previously described members of the genus Glaciecola. The polyphasic data obtained in this study clearly demonstrate that strain FR1064T represents a novel species of the genus Glaciecola. The name Glaciecola nitratireducens sp. nov. is therefore proposed, with strain FR1064T (=KCTC 12276T=JCM 12485T) as the type strain.

Marinobacter algicola sp. nov., isolated from laboratory cultures of paralytic shellfish toxin-producing dinoflagellates

Phylogenetic and phenotypic analysis of cultivable marine bacteria isolated from laboratory cultures of two paralytic shellfish toxin-producing dinoflagellates, Gymnodinium catenatum and Alexandrium tamarense, showed the presence of a novel group of Gram-negative, aerobic, moderately halophilic and hydrocarbon-degrading bacteria, related to the genus Marinobacter. The strains, designated DG893T, DG1136 and ATAM407-13, grew optimally in media with 3–6 % NaCl and at 25–30 °C, and all could utilize n-hexadecane and n-tetradecane as the sole carbon source. The strains had a 16S rRNA gene sequence similarity of 94·2–94·3 % to Marinobacter hydrocarbonoclasticus ATCC 27132, and a similarity of 97·5–97·8 % to the closest phylogenetically related type strain, Marinobacter flavimaris DSM 16070T. DNA–DNA hybridization levels to M. flavimaris and other Marinobacter type strains were ⩽42 %, while DNA–DNA reassociation values among DG893T, DG1136 and ATAM407-13 were ⩾83 %. The DNA G+C content was 54–55 mol% and the major isoprenoid quinone was ubiquinone-9. On the basis of phenotypic, chemotaxonomic, DNA–DNA hybridization and phylogenetic analysis, it is proposed that these three strains represent a novel species, Marinobacter algicola sp. nov. The type strain is DG893T (=DSM 16394T=NCIMB 14009T).

Characteristics of bacteria showing high denitrification activity in saline wastewater

AIMS

Denitrification efficiency at 10% salinity was compared with that at 2% salinity. The characteristics of bacterial strains isolated from the denitrification system, where an improvement of denitrification efficiency was observed at a high salinity were investigated.

METHODS AND RESULTS

Two continuous feeding denitrification systems for saline solutions of 2% and 10% salinity, were operated. Denitrification efficiency at 10% salinity was higher than that at 2% salinity. The bacterial strains were isolated using the trypticase soy agar (TSA) medium at 30 degrees C. The phylogenetic analysis of 16S rRNA gene sequences of isolates indicated that halophilic species were predominant at 10% salinity.

CONCLUSIONS

The improvement of denitrification efficiency at a high salinity was demonstrated. The strains isolated from the denitrifying system with 10% salinity were halophilic bacteria, Halomonas sp. and Marinobacter sp., suggesting that these bacteria show a high denitrifying activity at 10% salinity.

SIGNIFICANCE AND IMPACT OF THE STUDY

The long-term acclimated sludge used in this study resulted in high denitrification performance at a high salinity, indicating that the design of a high-performance denitrification system for saline wastewater will be possible.

Effects of nitrate treatment on a mixed species, oil field microbial biofilm

Biofilms of bacteria, indigenous to oil field produced water, were grown in square section, glass capillary flow cells at 45 degrees C. Initially, in situ image analysis microscopy revealed predominantly coccoid bacteria (length-to-width ratio measurements (l (c):w (c)) of bacterial cells gave a mean value of 1.1), while chemical measurements confirmed sulphate reduction and sulphide production. After nitrate ion addition at 100 and 80 mg/l, in the two repeat experiments respectively, the dominance of rod-shaped bacteria (mean l (c):w (c) = 2.8) was observed. This coincided with the occurrence of nitrate reduction in the treated flow cells. Beneficially, no significant increase in biofilm cover was observed after the addition of nitrate. The dominant culturable nitrate-reducing bacterium was Marinobacter aquaeolei. The l (c):w (c) ratio measured here concurs with previously reported cell dimensions for this organism. Several Marinobacter strains were also isolated from different oil fields in the North Sea where nitrate treatment has been applied to successfully treat reservoir souring, implying that this genus may play an important role in nitrate treatment.

Marinobacter maritimus sp. nov., a psychrotolerant strain isolated from sea water off the subantarctic Kerguelen islands

A psychrotolerant, Gram-negative, motile bacterium, designated CK 47T, was isolated from sea water off the subantarctic Kerguelen islands (50° 40′ S 68° 25′ E). The isolate grew optimally at 22 °C and minimum and maximum temperature of growth were 4 and 37 °C, respectively. It required Na+ for growth and exhibited optimum growth at pH 8·5 and 4 % NaCl. It utilized hexane, heptane and petroleum ether as sole sources of carbon. Strain CK 47T had Q9 as the major respiratory quinone and C16 : 0 (21·7 %), C17 : 0 (21·3 %), C18 : 0 (5·7 %), C18 : 1 ω7c (9·0 %) and C18 : 1 ω9c (31·4 %) as predominant fatty acids. The G+C content of the DNA was 58 mol%. Phylogenetic analysis based on the 16S rRNA gene sequence indicated that CK 47T formed a coherent cluster within the genus Marinobacter. It exhibited highest 16S rRNA gene sequence similarity of 96·8 % with Marinobacter lipolyticus. However, the level of DNA–DNA relatedness between strain CK47T and M. lipolyticus was only 55 %. On the basis of phenotypic characteristics, and phylogenetic and genotypic distinctiveness, strain CK 47T is considered to represent a novel species of the genus Marinobacter. The name Marinobacter maritimus sp. nov. is proposed, with CK 47T (=JCM 12521T=MTCC 6519T) as the type strain.

Saccharophagus degradans gen. nov., sp. nov., a versatile marine degrader of complex polysaccharides

Gammaproteobacteria belonging and related to the genus Microbulbifer are an emerging group of complex carbohydrate-degrading marine bacteria. Previously, all of the representatives were placed within Microbulbifer or were unclassified. Recently, a new genus, Teredinibacter, represented by a single species, Teredinibacter turnerae, was formed to include an endosymbiotic branch of these organisms. In this study, based on 16S rRNA gene sequence similarity and phenotypic analyses, a new genus, Saccharophagus, is proposed to accommodate the most versatile marine carbohydrate degrader yet identified, Saccharophagus degradans gen. nov., sp. nov. 2-40T (=ATCC 43961T=DSM 17024T). S. degradans strain 2-40T can degrade 10 tested complex polysaccharides: agar, alginate, chitin, cellulose, fucoidan, laminarin, pectin, pullulan, starch and xylan. S. degradans 2-40T shares 90·5 % 16S rRNA gene sequence similarity with the type strain of the Microbulbifer type species, Microbulbifer hydrolyticus IRE-31T, and 91·5 % with T. turnerae T7902T, and can be further distinguished from members of these two genera by 16S rRNA gene cluster analysis, the ability to utilize 10 different complex polysaccharides as sole carbon sources, a significantly lower G+C content and differences in fatty acid content. The three genera of complex polysaccharide-degrading, marine bacteria now encompass 20 strains from diverse marine niches.

Marinobacter hydrocarbonoclasticus Gauthier et al. 1992 and Marinobacter aquaeolei Nguyen et al. 1999 are heterotypic synonyms

The genus Marinobacter was described with a single species, Marinobacter hydrocarbonoclasticus Gauthier et al. 1992, to place a hydrocarbon-degrading marine bacterium belonging to the gamma-subclass of the Proteobacteria. Marinobacter aquaeolei Nguyen et al. 1999, the second described species of the genus, was proposed for a strain isolated from an oil-producing well on an offshore platform in southern Vietnam, on the basis of differences in the whole-cell protein pattern and lipopolysaccharide composition, although its phenotypic and genotypic characteristics were very similar to those of the type species, M. hydrocarbonoclasticus. In the present paper, literature data concerning the two species were reviewed. Fatty acid composition, G+C content and DNA-DNA hybridization studies were performed in order to clarify the taxonomic positions of these two species. Based on the results obtained in this study and phenotypic and phylogenetic traits available from the literature, it is proposed that the two species should be united under the same name; according to the rules of priority, M. hydrocarbonoclasticus, the first described species, is the earlier synonym and M. aquaeolei is the later synonym.

Marinobacter bryozoorum sp. nov. and Marinobacter sediminum sp. nov., novel bacteria from the marine environment

Two marine, Gram-negative, aerobic, halophilic strains, designated KMM 3657T and KMM 3840T, were isolated and found to be phylogenetically closely related to each other, showing 96·6 % 16S rRNA gene sequence similarity. Both strains are members of the genus Marinobacter in the γ-Proteobacteria (94·7–98·0 % 16S rRNA gene sequence similarity). Strain KMM 3657T and Marinobacter lipolyticus SM19T were closely related, with 98·0 % sequence similarity. The novel strains shared generic physiological and chemotaxonomic properties with Marinobacter species, but differed in their temperature range for growth, inability to grow in 20 % NaCl and at >43 °C, metabolic properties and fatty acid composition. On the basis of phenotypic and phylogenetic analysis data, it is proposed that the strains represent two novel species, Marinobacter bryozoorum sp. nov., with the type strain KMM 3840T (=50-11T=DSM 15401T), and Marinobacter sediminum sp. nov., with the type strain KMM 3657T (=R65T=DSM 15400T).

Salinimonas chungwhensis gen. nov., sp. nov., a moderately halophilic bacterium from a solar saltern in Korea

A halophilic non-spore-forming bacterium of the γ-Proteobacteria, designated strain BH030046T, was isolated from a solar saltern in Korea. Cells were Gram-negative, chemoheterotrophic, short rod-shaped and motile with a polar flagellum. Comparative 16S rRNA gene sequence analysis revealed that strain BH030046T formed a distinct lineage in the family Alteromonadaceae and was distinguished from its closest related genera Alteromonas (91·4–94·8 %), Aestuariibacter (92·1–93·5 %) and Glaciecola (92·1–93·5 %) on the basis of low 16S rRNA gene sequence similarities. Physiological and biochemical data also showed that the isolate was different from members of these three genera. The predominant cellular fatty acids were C16 : 0 and C18 : 1 ω7c. DNA G+C content was 48 mol% and the major isoprenoid quinone was Q-8. The strain grew optimally at 30–35 °C, pH 7·0–8·0 and 2–5 % NaCl. On the basis of physiological and molecular properties, strain BH030046T (=KCTC 12239T=DSM 16280T) represents a novel genus and species in the family Alteromonadaceae, for which the name Salinimonas chungwhensis gen. nov., sp. nov. is proposed.

Marinobacter flavimaris sp. nov. and Marinobacter daepoensis sp. nov., slightly halophilic organisms isolated from sea water of the Yellow Sea in Korea

Two Gram-negative, motile, non-spore-forming and slightly halophilic rods (strains SW-145T and SW-156T) were isolated from sea water of the Yellow Sea in Korea. Strains SW-145T and SW-156T grew optimally at 37 and 30–37 °C, respectively, and in the presence of 2–6 % (w/v) NaCl. Strains SW-145T and SW-156T were chemotaxonomically characterized as having ubiquinone-9 as the predominant respiratory lipoquinone and C16 : 0, C18 : 1 ω9c, C16 : 1 ω9c and C12 : 0 3-OH as the major fatty acids. The DNA G+C contents of strains SW-145T and SW-156T were 58 and 57 mol%, respectively. Phylogenetic analyses based on 16S rRNA gene sequences showed that strains SW-145T and SW-156T fell within the evolutionary radiation enclosed by the genus Marinobacter. The 16S rRNA gene sequences of strains SW-145T and SW-156T were 94·8 % similar. Strains SW-145T and SW-156T exhibited 16S rRNA gene sequence similarity levels of 94·3–98·1 and 95·4–97·7 %, respectively, with respect to the type strains of all Marinobacter species. Levels of DNA–DNA relatedness, together with 16S rRNA gene sequence similarity values, indicated that strains SW-145T and SW-156T are members of two species that are distinct from seven Marinobacter species with validly published names. On the basis of phenotypic properties and phylogenetic and genotypic distinctiveness, strains SW-145T (=KCTC 12185T=DSM 16070T) and SW-156T (=KCTC 12184T=DSM 16072T) should be placed in the genus Marinobacter as the type strains of two distinct novel species, for which the names Marinobacter flavimaris sp. nov. and Marinobacter daepoensis sp. nov. are proposed.

Glaciecola polaris sp. nov., a novel budding and prosthecate bacterium from the Arctic Ocean, and emended description of the genus Glaciecola

Four strains of cold-adapted, strictly aerobic and facultative oligotrophic bacteria were isolated from polar seas and investigated using a polyphasic taxonomic approach. Two strains (LMG 21857T and LMG 21854) derive from Arctic sea water whereas the other two strains (LMG 21855 and LMG 21858) were isolated from Antarctic sea water. Phylogenetic analysis based on 16S rRNA gene sequences indicated that these strains belong to the γ-subclass of the Proteobacteria and are related to the genus Glaciecola, with 98·0–99·7 % sequence similarity to Glaciecola mesophila and 94·2–95·3 % sequence similarity to Glaciecola punicea, their nearest phylogenetic neighbours. Two strains (LMG 21855 and LMG 21858) were identified as G. mesophila, whereas DNA–DNA hybridization results and differences in phenotypic characteristics showed that the other two strains (LMG 21857T and LMG 21854) constitute a novel species within the genus Glaciecola, with a DNA G+C content of 44·0 mol%. The isolates are Gram-negative, chemoheterotrophic, motile, rod-shaped cells that are psychrotolerant and moderately halophilic. Buds can be produced on mother cells and on prosthecae. Branch formation of prosthecae occurs. Whole-cell fatty acid profiles of the isolates are very similar and include C16 : 0 and C16 : 1 ω7c as the major fatty acid components. On the basis of genotypic and phenotypic properties, a novel species of the genus Glaciecola is described, for which the name Glaciecola polaris sp. nov. is proposed, with isolate LMG 21857T (=CIP 108324T=ARK 150T) as the type strain. An emended description of the genus Glaciecola is presented.

Thalassomonas ganghwensis sp. nov., isolated from tidal flat sediment

A Gram-negative, aerobic, halophilic bacterium, designated strain JC2041(T), was isolated from a sediment sample of getbol, the Korean tidal flat. Results of 16S rDNA sequence analyses indicated a moderate relationship to Thalassomonas viridans within the gamma-Proteobacteria (94.9 % similarity). Depending on the tree-making algorithm used, the isolate either formed a monophyletic clade with T. viridans or was recovered as a sister group of a class containing the genera Thalassomonas and Colwellia. Phenotypic features of the getbol isolate were similar to those of T. viridans, but several physiological and chemotaxonomic properties, including nitrate reduction, amylase, lecithinase, Tweenase and utilization of 13 carbon sources, distinguished strain JC2041(T) from T. viridans. The polyphasic data presented in this study indicate that the isolate should be classified as a novel species in the genus Thalassomonas. The name Thalassomonas ganghwensis sp. nov. is therefore proposed for the getbol isolate; the type strain is JC2041(T) (=IMSNU 14005(T)=KCTC 12041(T)=DSM 15355(T)).

Microbulbifer maritimus sp. nov., isolated from an intertidal sediment from the Yellow Sea, Korea

A Gram-negative, rod-shaped, non-spore-forming, slightly halophilic bacterium (strain TF-17T) was isolated from an intertidal sediment from the Yellow Sea, Korea. Pigment of strain TF-17T was similar to that of Microbulbifer elongatus, but different from those of Microbulbifer hydrolyticus and Microbulbifer salipaludis. Strain TF-17T was distinguishable from M. elongatus by some phenotypic properties, including motility, optimal growth temperature and others. Phylogenetic analysis based on 16S rDNA sequences showed that strain TF-17T clustered with the type strains of the three Microbulbifer species with validly published names. Strain TF-17T exhibited 16S rDNA sequence similarity levels of 95·1–95·7 % to the type strains of the three Microbulbifer species. The predominant respiratory lipoquinone found in strain TF-17T was ubiquinone-8. The major fatty acid was iso-C15 : 0 and significant amounts of iso-C11 : 0 3-OH and iso-C17 : 1 ω9c were also present. The DNA G+C content of strain TF-17T was 59·9 mol%. Levels of DNA–DNA relatedness between strain TF-17T and the type strains of the three Microbulbifer species were in the range 10·0–13·0 %. On the basis of phenotypic and phylogenetic data and genotypic distinctiveness, strain TF-17T (=KCCM 41774T=JCM 12187T) is proposed as the type strain of a novel species of the genus Microbulbifer, Microbulbifer maritimus sp. nov.

Agarivorans albus gen. nov., sp. nov., a γ-proteobacterium isolated from marine animals

Six bacterial strains were isolated from healthy marine organisms that were collected from the coast of the Kanto area in Japan. Phylogenetic analysis based on 16S rDNA sequence similarity showed that the six isolates formed a separate cluster in the γ-Proteobacteria and were related to the genera Alteromonas and Glaciecola (<91·6 % similarity). The isolates were related closely to each other (DNA–DNA reassociation values of 74–93 %). The isolates had a polar flagellum and were Gram-negative, mesophilic, strictly aerobic rods that required salt for growth. Distinct phenotypic features of this group included the ability to hydrolyse agar and white pigmentation of colonies. The DNA G+C content of the isolates was 48–50 mol%. The major quinone was Q-8. Phenotypic characteristics of the isolates differed from those of members of the genera Alteromonas and Glaciecola. The name Agarivorans albus gen. nov., sp. nov. is proposed for the six isolates; the type strain is MKT 106T (=IAM 14998T=LMG 21761T).

Aestuariibacter salexigens gen. nov., sp. nov. and Aestuariibacter halophilus sp. nov., isolated from tidal flat sediment, and emended description of Alteromonas macleodii

Two strictly aerobic, halophilic strains of the γ-Proteobacteria, designated JC2042T and JC2043T, were obtained from a sediment sample of getbol, the Korean tidal flat. Comparative 16S rDNA sequence studies revealed that the test strains were related most closely to the type strains of the genera Alteromonas (93·5–95·5 %) and Glaciecola (91·1–93·3 %). Phylogenetic analyses demonstrated that strains JC2042T and JC2043T formed a distinct monophyletic clade within the family Alteromonadaceae and clustered distantly with the genera Alteromonas and Glaciecola. Physiological, biochemical and chemotaxonomic data also indicated that the two getbol isolates were significantly different from members of these two genera and others with validly published names. Cells were rod-shaped and motile with a polar flagellum. The major isoprenoid quinone was Q8. The predominant cellular fatty acids were C16 : 0, C18 : 1 ω7c and a mixture of C16 : 1 ω7c and iso-C15 : 0 2-OH. DNA G+C contents were 48–54 mol%. On the basis of this polyphasic study, Aestuariibacter gen. nov. is proposed with two novel species, Aestuariibacter salexigens sp. nov. (type strain, JC2042T=IMSNU 14006T=KCTC 12042T=DSM 15300T) and Aestuariibacter halophilus sp. nov. (type strain, JC2043T=IMSNU 14007T=KCTC 12043T=DSM 15266T). Aestuariibacter salexigens is the type species of the genus. In addition, an emended description of Alteromonas macleodii is proposed.

Enzymatic properties and nucleotide and amino acid sequences of a thermostable beta-agarase from a novel species of deep-sea Microbulbifer

An agar-degrading bacterium, strain JAMB-A7, was isolated from the sediment in Sagami Bay, Japan, at a depth of 1,174 m and identified as a novel species of the genus Microbulbifer. The gene for a novel beta-agarase from the isolate was cloned and sequenced. It encodes a protein of 441 amino acids with a calculated molecular mass of 48,989 Da. The deduced amino acid sequence showed similarity to those of known beta-agarases in glycoside hydrolase family 16, with only 34-55% identity. A sequence similar to a carbohydrate-binding module was found in the C-terminal region of the enzyme. The recombinant agarase was hyper-produced extracellularly using Bacillus subtilis as the host, and the enzyme purified to homogeneity had a specific activity of 398 U (mg protein)(-1) at pH 7.0 and 50 degrees C. It was thermostable, with a half-life of 502 min at 50 degrees C. The optimal pH and temperature for activity were around 7 and 50 degrees C, respectively. The pattern of agarose hydrolysis showed that the enzyme was an endo-type beta-agarase, and the final main product was neoagarotetraose. The activity was not inhibited by NaCl, EDTA, and various surfactants at high concentrations. In particular, sodium dodecyl sulfate had no inhibitory effect up to 2%.

Microbulbifer arenaceous sp. nov., a new endolithic bacterium isolated from the inside of red sandstone

An endolithic bacterium, strain RSBr-1, was isolated from the inside of a piece of red sandstone from coastal areas of Scotland. RSBr-1 was gram negative, oxidase and catalase positive, and cells were non-motile rods. Sodium was required for growth. The optimum sodium chloride concentration and pH for growth were 4% and pH 8.0, respectively. Eumelanin was produced in marine broth and in BY medium. RSBr-1 hydrolyzes chitin, esculin, gelatin, and starch, but not agar. Nitrate reduction is positive. Taxonomic characterization of this strain indicated that it belongs to the genus Microbulbifer. The difference between the aligned 16S rDNA sequences of RSBr-1 and the closest relative, M. elongata, is greater than the difference between the 16S rDNA sequences of M. hydrolyticus and M. elongata. On the basis of the phenotypic and genotypic comparison of this isolate with the other strains, RSBr-1 is proposed as a new species, Microbulbifer arenaceous, with type strain RSBr-1.

Marinobacter excellens sp. nov., isolated from sediments of the Sea of Japan

Five strains of halophilic, Gram-negative marine bacteria (KMM 3809(T), KMM 3814, KMM 3815, KMM 3817 and KMM 3818) were isolated from sediments collected from Chazhma Bay, Sea of Japan. Phylogenetic 16S rRNA gene sequence-based analysis placed these bacteria in a clade within the genus Marinobacter in the gamma-Proteobacteria. KMM 3809(T) showed highest 16S rRNA gene sequence similarity of 97.3 % to Marinobacter litoralis and 96.9 % to Marinobacter hydrocarbonoclasticus and Marinobacter aquaeolei. DNA-DNA hybridization between the five isolates was at the conspecific level (94-96 %) and that among the closest phylogenetic neighbours ranged from 45.0 to 62.5 %. The new organisms were susceptible to polymyxin. Predominant fatty acids were C(16 : 0), C(16 : 1)omega9c, C(16 : 1)omega7c and C(18 : 1)omega9c. Phylogenetic evidence, along with phenotypic and genotypic characteristics, showed that the bacteria constituted a novel species of the genus Marinobacter. The name Marinobacter excellens sp. nov. is proposed for this species, with the type strain KMM 3809(T) (=CIP 107686(T)).

Idiomarina loihiensis sp. nov., a halophilic -Proteobacterium from the Lo'ihi submarine volcano, Hawai'i

During an investigation of bacterial diversity at hydrothermal vents on the Lō'ihi Seamount, Hawai'i, a novel bacterium (designated L2-TR(T)) was cultivated, which shares 99.9 % 16S rRNA gene sequence similarity over 1415 nt with an uncultured eubacterium from sediment at a depth of 11 000 m in the Mariana Trench. The nearest cultivated neighbour of L2-TR(T), however, is Idiomarina abyssalis KMM 227(T), with which it shares 98.9 % 16S rRNA sequence similarity. L2-TR(T) differed from I. abyssalis KMM 227(T) in several phenotypic respects, including growth at 46 degrees C and in medium that contained 20 % (w/v) NaCl. DNA-DNA hybridization data showed that L2-TR(T) did not belong to the species I. abyssalis (43.4 % DNA-DNA reassociation). Cells of L2-TR(T) were Gram-negative rods, 0.35 microm wide and 0.7-1.0 microm long, which were occasionally up to 1.8 microm in length. Cells were motile by a single polar or subpolar flagellum. The major fatty acid in L2-TR(T) was iso-C(15 : 0) (32.6 %). The DNA G+C content was 47.4 mol%. Phenotypic and genotypic analyses indicated that L2-TR(T) could be assigned to the genus Idiomarina but, based on significant phenotypic and genotypic differences, constituted a novel species within this genus, Idiomarina loihiensis sp. nov., of which L2-TR(T) (=ATCC BAA-735(T)=DSM 15497(T)) is the type strain.

Marinobacter lipolyticus sp. nov., a novel moderate halophile with lipolytic activity

In the course of a screening programme in hypersaline habitats of southern Spain to isolate halophilic bacteria that are able to produce different extracellular enzymes, a novel, moderately halophilic bacterium (strain SM19(T)) that displays lipolytic activity has been isolated and characterized. Strain SM19(T) is a Gram-negative rod that grows optimally in culture media that contain 7.5 % NaCl. The DNA G+C content was 57.0 mol%. According to phenotypic and genotypic data, this strain was assigned to the genus MARINOBACTER: However, 16S rDNA sequence similarity between strain SM19(T) and species of the genus Marinobacter was <96.7 %; this value is sufficiently low to propose its designation as a novel species. In addition, DNA-DNA hybridization with reference strains of close phylogenetic relatives was between 11 and 19 %. On the basis of these data, the inclusion of strain SM19(T) in the genus Marinobacter as a novel species is proposed, with the name Marinobacter lipolyticus sp. nov. The type strain of the novel species is SM19(T) (=DSM 15157(T)=NCIMB 13907(T)=CIP 107627(T)=CCM 7048(T)).

Transfer of Pseudomonas elongata Humm 1946 to the genus Microbulbifer as Microbulbifer elongatus comb. nov

Phylogenetic analysis based on 16S rDNA sequences revealed that Pseudomonas elongata Humm 1946 is more closely related to the genus Microbulbifer than to authentic pseudomonads. The type strain of P. elongata (DSM 6810(T)) exhibited 16S rDNA similarity levels of 97.5 and 98.2 % to the type strains of Microbulbifer hydrolyticus and Microbulbifer salipaludis, respectively, but of less than approximately 92 % to Pseudomonas species with known 16S rDNA sequences. Respiratory lipoquinone and cellular fatty acid analyses showed that the type strain of P. elongata has characteristics similar to those of the genus Microbulbifer, not those of the genus Pseudomonas. P. elongata DSM 6810(T) contained ubiquinone-8 as the predominant respiratory lipoquinone and iso-C(15 : 0) as the major fatty acid. DNA-DNA relatedness data indicate that P. elongata is a species distinct from M. hydrolyticus and M. salipaludis. Therefore, on the basis of these data, P. elongata Humm 1946 should be transferred to the genus Microbulbifer as Microbulbifer elongatus comb. nov.

Glaciecola mesophila sp. nov., a novel marine agar-digesting bacterium

Alteromonas-like strains KMM 241(T) and KMM 642, isolated from marine invertebrate specimens, were investigated to clarify their taxonomic position. The novel isolates were aerobic, Gram-negative, motile, slightly halophilic and heterotrophic and hydrolysed polysaccharides. They did not hydrolyse urea, gelatin or casein and produced acid weakly from carbohydrates. The DNA G + C content ranged between 44.6 and 44.8 mol%. DNA-DNA similarity between the two strains was 71%. Comparison of the 16S rRNA gene sequence of strain KMM 241(T) revealed 94.5-94.8% similarity to Glaciecola species. The novel strains shared several phenotypic and physiological properties with members of Glaciecola, but they differed in their lack of pigment production, their minimal and maximal growth temperatures and their ability to hydrolyse agar and carrageenan and in the utilization of organic compounds. On the basis of phenotypic and physiological characteristics as well as phylogenetic analysis, the isolates should be assigned to a novel species, Glaciecola mesophila sp. nov. The type strain is strain KMM 241(T) (=DSM 15026(T)).

Marinobacter lutaoensis sp. nov., a thermotolerant marine bacterium isolated from a coastal hot spring in Lutao, Taiwan

A heterotrophic and thermotolerant marine bacterium, designated strain T5054, was isolated from a hot spring on the coast of Lutao, Taiwan. It was a strictly aerobic, Gram-negative rod. Cells grown in broth cultures were non-spore-forming and motile by means of one to several polar flagella. It seems that pilus-like structures were produced from both poles of the cells. Strain T5054 required Na+ for growth and exhibited optimal growth at about 45 degrees C, pH 7, and 3-5% NaCl. It contained iso-C15:0 as the most abundant fatty acid and ubiquinone-8 as the only isoprenoid quinone. Its genomic DNA G+C content was 63.5 mol%. The strain did not require vitamins or other organic growth factors, and it grew on glucose, mannitol, and a variety of organic acids and amino acids as sole carbon sources. Characterization data, together with the results of a 16S rDNA-based phylogenetic analysis, indicated that strain T5054 could be classified as a new species in the genus Marinobacter. The name Marinobacter lutaoensis sp. nov. is proposed for this new bacterium. The type strain is T5054 (CCRC 17087; JCM 11179).

Marinobacter litoralis sp. nov., a moderately halophilic bacterium isolated from sea water from the East Sea in Korea

A Gram-negative, motile, non-spore-forming and moderately halophilic rod-shaped strain, SW-45T, was isolated from sea water of the East Sea in Korea. The organism grew optimally at 30-37 degrees C and grew at 4 and 46 degrees C. It grew in the presence of 0.5-18% (v/w) NaCl, with an optimum of 2-7% NaCl. Strain SW-45T was chemotaxonomically characterized by having ubiquinone-9 (Q-9) as the major respiratory lipoquinone and C16 : 0, C18 : 1omega9c and C16 : 1omega9c as the predominant fatty acids. The DNA G + C content was found to be 55 mol%. Phylogenetic analysis based on 16S rDNA sequences showed that strain SW-45T forms a coherent cluster with the clade comprising the two Marinobacter species. 16S rDNA sequence similarities between strain SW-45T and the Marinobacter species was 94.9% to Marinobacter hydrocarbonoclasticus DSM 8798T and 95.3% to Marinobacter aquaeolei DSM 11845T. Levels of DNA-DNA relatedness between strain SW-45T and the type strains of M. hydrocarbonoclasticus and M. aquaeolei were respectively 4.3 and 5.5%. On the basis of phenotypic properties, phylogeny and genomic data, strain SW-45T (=KCCM 41591T =JCM 11547T) should be placed in the genus Marinobacter as a member of a novel species, for which the name Marinobacter litoralis sp. nov. is proposed. As part of this study, the major respiratory lipoquinone of M. hydrocarbonoclasticus and M. aquaeolei was also found to be Q-9.

Psychromonas arctica sp. nov., a novel psychrotolerant, biofilm-forming bacterium isolated from Spitzbergen

Using starch as a carbon source at a cultivation temperature of 4 degrees C, a number of Gram-negative, aerobic strains was isolated from sea-ice and sea-water samples collected at Spitzbergen in the Arctic. Analysis of the genetic diversity of the novel isolates by random amplification of polymorphic DNA (RAPD) and ERIC fingerprinting revealed a homogenic group of biofilm-forming bacteria that contained small extrachromosomal elements. As a representative of the group, strain Pull 5.3T, isolated from a sea-water sample, was used for detailed characterization. The results of phylogenetic analysis indicated that the newly isolated strain is a member of the gamma-subclass of the Proteobacteria and belongs to the genus Psychromonas. On the basis of DNA-DNA hybridization experiments, chemotaxonomic studies and phenotypic characterization, strain Pull 5.3T (=CECT 5674T =DSM 14288T) clearly represents a novel species, for which the name Psychromonas arctica sp. nov. is proposed.

Psychromonas profunda sp. nov., a psychropiezophilic bacterium from deep Atlantic sediments

A psychropiezophilic bacterium, strain 2825T (=LMG 21260T =JCM 11437T), isolated from deep Atlantic sediments at a depth of 2770 m and a temperature of 2 degrees C, was found by polyphasic analysis to represent a novel species of the genus Psychromonas, Psychromonas profunda sp. nov. It is a strict psychrophile and a moderate piezophile, whose degree of piezophily is increased markedly when the temperature is raised to 10 degrees C. The piezophily of P. profunda is intermediate between that of the type species, Psychromonas antarctica, which is not piezophilic, and that of Psychromonas kaikoae, which is an obligate piezophile.

Microbulbifer salipaludis sp. nov., a moderate halophile isolated from a Korean salt marsh

A Gram-negative, non-motile, non-spore-forming, moderately halophilic rod (strain SM-1T) was isolated from salt marsh around the junction of the Youngsan River and the Yellow Sea in Korea and subjected to a polyphasic taxonomic study. This organism grew optimally at 37 degrees C and was able to grow at 10 and 45 degrees C. It grew optimally in the presence of 2-3% (w/v) NaCl. The major fatty acids in strain SM-1T were iso-C15:0 and C16:0. Strain SM-1T and Microbulbifer hydrolyticus DSM 11525T were characterized by having ubiquinone-8 as the predominant respiratory lipoquinone. The DNA G+C content of strain SM-1T was 59 mol%. Phylogenetic analysis based on 16S rDNA sequences showed that strain SM-1T formed a coherent cluster with M. hydrolyticus; this relationship was supported by a bootstrap resampling value of 100%. The level of 16S rDNA identity between strain SM-1T and the type strain of M. hydrolyticus was 98.6%. The mean level of DNA-DNA relatedness between strain SM-1T and the type strain of M. hydrolyticus was 20.6%. Therefore, on the basis of phenotypic properties, phylogeny and genomic data, strain SM-1T should be placed in the genus Microbulbifer as a member of a novel species, for which the name Microbulbifer salipaludis sp. nov. is proposed. The type strain of the novel species is strain SM-1T (=KCCM 41586T =JCM 11542T).

Psychromonas kaikoae sp. nov., a novel from the deepest piezophilic bacterium cold-seep sediments in the Japan Trench

Two strains of obligately piezophilic bacteria were isolated from sediment collected from the deepest cold-seep environment with chemosynthesis-based animal communities within the Japan Trench, at a depth of 7434 m. The isolated strains, JT7301 and JT7304T, were closely affiliated with members of the genus Psychromonas on the basis of 16S rDNA sequence analysis. Hybridization values for DNA-DNA relatedness between these strains and the Psychromonas antarctica reference strain were significantly lower than that accepted as the phylogenetic definition of a species. The optimal temperature and pressure for growth of the isolates were 10 degrees C and 50 MPa and they produced both eicosapentaenoic acid (C20:5omega3) and docosahexaenoic acid (C22:6) in the membrane layer. Based on the taxonomic differences observed, the isolated strains appear to represent a novel obligately piezophilic Psychromonas species. The name Psychromonas kaikoae sp. nov. (type strain JT7304T = JCM 11054T = ATCC BAA-363T) is proposed. This is the first proposed obligately piezophilic species of the genus Psychromonas.

Psychromonas marina sp. nov., a novel halophilic, facultatively psychrophilic bacterium isolated from the coast of the Okhotsk Sea

A facultatively psychrophilic bacterium, strain 4-22T, was isolated from a cold current off the Monbetsu coast of the Okhotsk Sea in Hokkaido, Japan. The isolate was a rod-shaped facultative anaerobe that reduced nitrate to nitrite and hydrolysed starch, DNA and alginic acid, but not chitin or gelatin. The isolate grew at 0 degrees C, but not at 26 degrees C; the optimum growth temperature was 14-16 degrees C. NaCl was required for growth. The DNA G+C content was 43.5 mol%. The whole-cell fatty acids consisted of significant amounts of an unsaturated fatty acid, C16:1, and a saturated fatty acid, C16:0. A polyunsaturated fatty acid, docosahexaenoic acid (C22:6), was also detected (1.6%). Phylogenetic analysis based on 16S rRNA gene sequences showed that strain 4-22T was closely related to Psychromonas antarctica (95.7% similarity). DNA-DNA hybridization revealed a relatedness of 31% between strain 4-22T and P. antarctica. Based on physiological and biochemical characteristics and the phylogenetic position as determined by 16S rRNA gene analysis and DNA-DNA relatedness, it is concluded that the isolate represents a novel species, for which the name Psychromonas marina sp. nov. is proposed. The type strain is 4-22T (= JCM 10501T = IAM 14899T = NCIMB 13792T).