Pseudidiomarina piscicola sp. nov., isolated from cultured European seabass, Dicenthrarchus labrax.

Strain CECT 9734 T, a Gram-negative, aerobic, chemoorganotrophic bacterium, motile by polar flagella, was isolated from cultured European seabass, Dicenthrarchus labrax, in Spain. It grows from 5 to 42 ºC, 6-9 pH and 1-12% total salinity. Major cellular fatty acids are C15:0 iso, summed feature 9 (C17:1 iso w9c/C16:0 10-methyl) and C17:0 iso. The genome size is 2.5 Mbp and G + C content is 49.5 mol%. Comparative analysis of the 16S rRNA gene sequence shows that the strain is a member of Pseudidiomarina, with highest similarities with Pseudidiomarina halophila (97.0%) and Pseudidiomarina salinarum (96.9%). Phylogenomic tree based on UBCG program shows P. halophila as its closest relative. ANI and in-silico DDH with other Pseudidiomarina spp. are lower than 87 and 20%, respectively, suggesting that strain CECT 9734 T represents a new species, for which we propose the name Pseudidiomarina piscicola sp. nov. and CECT 9734 T (= LUBLD50 7aT = LMG 31044 T) as type strain.

Molecular Characterization of a Novel 1,3-α-3,6-Anhydro-L-Galactosidase, Ahg943, with Cold- and High-Salt-Tolerance from Gayadomonas joobiniege G7.

1,3-α-3,6-anhydro-L-galactosidase (α-neoagarooligosaccharide hydrolase) catalyzes the last step of agar degradation by hydrolyzing neoagarobiose into monomers, D-galactose, and 3,6-anhydro-Lgalactose, which is important for the bioindustrial application of algal biomass. Ahg943, from the agarolytic marine bacterium Gayadomonas joobiniege G7, is composed of 423 amino acids (47.96 kDa), including a 22-amino acid signal peptide. It was found to have 67% identity with the α-neoagarooligosaccharide hydrolase ZgAhgA, from Zobellia galactanivorans, but low identity (< 40%) with the other α-neoagarooligosaccharide hydrolases reported. The recombinant Ahg943 (rAhg943, 47.89 kDa), purified from Escherichia coli, was estimated to be a monomer upon gel filtration chromatography, making it quite distinct from other α-neoagarooligosaccharide hydrolases. The rAhg943 hydrolyzed neoagarobiose, neoagarotetraose, and neoagarohexaose into D-galactose, neoagarotriose, and neoagaropentaose, respectively, with a common product, 3,6- anhydro-L-galactose, indicating that it is an exo-acting α-neoagarooligosaccharide hydrolase that releases 3,6-anhydro-L-galactose by hydrolyzing α-1,3 glycosidic bonds from the nonreducing ends of neoagarooligosaccharides. The optimum pH and temperature of Ahg943 activity were 6.0 and 20°C, respectively. In particular, rAhg943 could maintain enzyme activity at 10°C (71% of the maximum). Complete inhibition of rAhg943 activity by 0.5 mM EDTA was restored and even, remarkably, enhanced by Ca2+ ions. rAhg943 activity was at maximum at 0.5 M NaCl and maintained above 73% of the maximum at 3M NaCl. Km and Vmax of rAhg943 toward neoagarobiose were 9.7 mg/ml and 250 µM/min (3 U/mg), respectively. Therefore, Ahg943 is a unique α-neoagarooligosaccharide hydrolase that has cold- and high-salt-adapted features, and possibly exists as a monomer.

Sources and selection of snow-specific microbial communities in a Greenlandic sea ice snow cover.

Sea ice and its snow cover are critical for global processes including climate regulation and biogeochemical cycles. Despite an increase in studies focused on snow microorganisms, the ecology of snow inhabitants remains unclear. In this study, we investigated sources and selection of a snowpack-specific microbial community by comparing metagenomes from samples collected in a Greenlandic fjord within a vertical profile including atmosphere, snowpack with four distinct layers of snow, sea ice brine and seawater. Microbial communities in all snow layers derived from mixed sources, both marine and terrestrial, and were more similar to atmospheric communities than to sea ice or seawater communities. The surface snow metagenomes were characterized by the occurrence of genes involved in photochemical stress resistance, primary production and metabolism of diverse carbon sources. The basal saline snow layer that was in direct contact with the sea ice surface harbored a higher abundance of cells than the overlying snow layers, with a predominance of Alteromonadales and a higher relative abundance of marine representatives. However, the overall taxonomic structure of the saline layer was more similar to that of other snow layers and the atmosphere than to underlying sea ice and seawater. The expulsion of relatively nutrient-rich sea ice brine into basal snow might have stimulated the growth of copiotrophic psychro- and halotolerant snow members. Our study indicates that the size, composition and function of snowpack microbial communities over sea ice were influenced primarily by atmospheric deposition and inflow of sea ice brine and that they form a snow-specific assemblage reflecting the particular environmental conditions of the snowpack habitat.

Low-temperature chemotaxis, halotaxis and chemohalotaxis by the psychrophilic marine bacterium Colwellia psychrerythraea 34H.

A variety of ecologically important processes are driven by bacterial motility and taxis, yet these basic bacterial behaviours remain understudied in cold habitats. Here, we present a series of experiments designed to test the chemotactic ability of the model marine psychrophilic bacterium Colwellia psychrerythraea 34H, when grown at optimal temperature and salinity (8°C, 35 ppt) or its original isolation conditions (-1°C, 35 ppt), towards serine and mannose at temperatures from -8°C to 27°C (above its upper growth temperature of 18°C), and at salinities of 15, 35 and 55 ppt (at 8°C and -1°C). Results indicate that C. psychrerythraea 34H is capable of chemotaxis at all temperatures tested, with strongest chemotaxis at the temperature at which it was first grown, whether 8°C or -1°C. This model marine psychrophile also showed significant halotaxis towards 15 and 55 ppt solutions, as well as strong substrate-specific chemohalotaxis. We suggest that such patterns of taxis may enable bacteria to colonize sea ice, position themselves optimally within its extremely cold, hypersaline and temporally fluctuating microenvironments, and respond to various chemical signals therein.

Salinity fluctuation influencing biological adaptation: growth dynamics and Na+ /K+ -ATPase activity in a euryhaline bacterium.

Although salinity fluctuation is a prominent characteristic of many coastal ecosystems, its effects on biological adaptation have not yet been fully recognized. To test the salinity fluctuations on biological adaptation, population growth dynamics and Na+ /K+ -ATPase activity were investigated in the euryhaline bacterium Idiomarina sp. DYB, which was acclimated at different salinity exposure levels, exposure times, and shifts in direction of salinity. Results showed: (1) bacterial population growth dynamics and Na+ /K+ -ATPase activity changed significantly in response to salinity fluctuation; (2) patterns of variation in bacterial growth dynamics were related to exposure times, levels of salinity, and shifts in direction of salinity change; (3) significant tradeoffs were detected between growth rate (r) and carrying capacity (K) on the one hand, and Na+ /K+ -ATPase activity on the other; and (4) beneficial acclimation was confirmed in Idiomarina sp. DYB. In brief, this study demonstrated that salinity fluctuation can change the population growth dynamics, Na+ /K+ -ATPase activity, and tradeoffs between r, K, and Na+ /K+ -ATPase activity, thus facilitating bacterial adaption in a changing environment. These findings provide constructive information for determining biological response patterns to environmental change.

An alternative polysaccharide uptake mechanism of marine bacteria.

Heterotrophic microbial communities process much of the carbon fixed by phytoplankton in the ocean, thus having a critical role in the global carbon cycle. A major fraction of the phytoplankton-derived substrates are high-molecular-weight (HMW) polysaccharides. For bacterial uptake, these substrates must initially be hydrolysed to smaller sizes by extracellular enzymes. We investigated polysaccharide hydrolysis by microbial communities during a transect of the Atlantic Ocean, and serendipitously discovered-using super-resolution structured illumination microscopy-that up to 26% of total cells showed uptake of fluorescently labelled polysaccharides (FLA-PS). Fluorescence in situ hybridisation identified these organisms as members of the bacterial phyla Bacteroidetes and Planctomycetes and the gammaproteobacterial genus Catenovulum. Simultaneous membrane staining with nile red indicated that the FLA-PS labelling occurred in the cell but not in the cytoplasm. The dynamics of FLA-PS staining was further investigated in pure culture experiments using Gramella forsetii, a marine member of Bacteroidetes. The staining patterns observed in environmental samples and pure culture tests are consistent with a 'selfish' uptake mechanisms of larger oligosaccharides (>600 Da), as demonstrated for gut Bacteroidetes. Ecologically, this alternative polysaccharide uptake mechanism secures substantial quantities of substrate in the periplasmic space, where further processing can occur without diffusive loss. Such a mechanism challenges the paradigm that hydrolysis of HMW substrates inevitably yields low-molecular-weight fragments that are available to the surrounding community and demonstrates the importance of an alternative mechanism of polysaccharide uptake in marine bacteria.

Catenovulum maritimus sp. nov., a novel agarolytic gammaproteobacterium isolated from the marine alga Porphyra yezoensis Ueda (AST58-103), and emended description of the genus Catenovulum.

A novel agarolytic, Gram-stain negative, heterotrophic, facultatively anaerobic and pale-white pigmented bacterial strain, designated Q1(T), was isolated from the marine alga Porphyra yezoensis Ueda (AST58-103) collected from the coastal area of Weihai, China. The cells are motile by means of peritrichous flagella. The isolate requires NaCl for growth, while seawater is not necessary, and growth occurs optimally at about 30-33 °C, in 1-3 % (w/v) NaCl and at pH 7-7.5. Strain Q1(T) shows oxidase-positive and catalase-negative activities, and possesses the ability to hydrolyse starch and alginate, but not cellulose, gelatin, urea or Tween-80. Phylogenetic analysis based on 16S rRNA gene sequence indicated that strain Q1(T) is affiliated with the family Alteromonadaceae within the class Gammaproteobacteria. The isolate, strain Q1(T), is most closely related to Catenovulum agarivorans YM01(T) (94.85 %), with less than 91.2 % sequence similarity to other close relatives with validly published names. The draft genome sequence of strain Q1(T) consists of 62 contigs (>200 bp) of 4,548,270 bp. The genomes of Q1(T) and YM01(T) have an ANI value of 70.7 %, and the POCP value between the two genomes is 64.4 %. The genomic DNA G+C content of strain Q1(T) is 37.9 mol% as calculated from the draft genome sequence. The main isoprenoid quinone is ubiquinone-8. The predominant cellular fatty acids are summed feature 3 (C16:1 ω7c and/or iso-C15:0 2-OH), C16:0 and C18:1 ω7c. The major polar lipids are phosphatidylethanolamine and phosphatidylglycerol. Based on data from a polyphasic chemotaxonomic, physiological and biochemical study, strain Q1(T) should be classified as a novel species of the genus Catenovulum, for which the name Catenovulum maritimus sp. nov. is proposed. The type strain is Q1(T) (=CICC 10836(T)=DSM 28813(T)).

Measuring bacterial activity and community composition at high hydrostatic pressure using a novel experimental approach: a pilot study.

In this pilot study, we describe a high-pressure incubation system allowing multiple subsampling of a pressurized culture without decompression. The system was tested using one piezophilic (Photobacterium profundum), one piezotolerant (Colwellia maris) bacterial strain and a decompressed sample from the Mediterranean deep sea (3044 m) determining bacterial community composition, protein production (BPP) and cell multiplication rates (BCM) up to 27 MPa. The results showed elevation of BPP at high pressure was by a factor of 1.5 ± 1.4 and 3.9 ± 2.3 for P. profundum and C. maris, respectively, compared to ambient-pressure treatments and by a factor of 6.9 ± 3.8 fold in the field samples. In P. profundum and C. maris, BCM at high pressure was elevated (3.1 ± 1.5 and 2.9 ± 1.7 fold, respectively) compared to the ambient-pressure treatments. After 3 days of incubation at 27 MPa, the natural bacterial deep-sea community was dominated by one phylum of the genus Exiguobacterium, indicating the rapid selection of piezotolerant bacteria. In future studies, our novel incubation system could be part of an isopiestic pressure chain, allowing more accurate measurement of bacterial activity rates which is important both for modeling and for predicting the efficiency of the oceanic carbon pump.

Pseudobowmanella zhangzhouensis gen. nov., sp. nov., isolated from the surface freshwater of the Jiulong River in China.

A strain, JS7-9(T), which was isolated from the surface freshwater of the Jiulong River, China, was subjected to taxonomic study. The bacterium was Gram-negative, facultatively anaerobic, rod-shaped and motile by means of a single polar flagellum. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain JS7-9(T) is affiliated to the family Alteromonadaceae, showing 90.5-94.2 % of 16S rRNA gene sequence similarity with the genera Bowmanella (94.0-94.2 %), Aestuariibacter (93.0-93.5 %), Glaciecola (91.0-93.1 %), Alteromonas (90.5-93.1 %) and Salinimonas (90.6-91.8 %). The major fatty acids were identified as C16:0, Sum In Feature 3 (C16:1 ω7c/ω6c), Sum In Feature 8 (C18:1 ω7c/ω6c) and C17:1 ω8c, and Q-8 as the predominant isoprenoid quinone. Based on the phenotypic, chemotaxonomic and phylogenetic distinctiveness, strain JS7-9(T) is considered to represent a novel species of a novel genus of the family Alteromonadaceae, for which the name Pseudobowmanella zhangzhouensis gen. nov., sp. nov. is proposed, with the type strain JS7-9(T) (=MCCC 1A00758(T) = KCTC 42143(T)).

Agarivorans litoreus sp. nov., a novel gammaproteobacterium isolated from seawater and emended description of the genus Agarivorans.

A Gram-stain negative, aerobic, non-spore-forming, motile and rod-shaped or ovoid bacterial strain, designated GJSW-6(T), was isolated from a seawater collected at Geoje island on the South Sea, South Korea, and subjected to polyphasic taxonomic study. Strain GJSW-6(T) was found to grow optimally at 30 °C, at pH 7.0-8.0 and in the presence of approximately 2.0 % (w/v) NaCl. Phylogenetic trees based on 16S rRNA gene sequences revealed that strain GJSW-6(T) clustered with the type strains of two Agarivorans species, Agarivorans albus and Agarivorans gilvus, with which it exhibited sequence similarity values of 99.17 and 95.88 %, respectively. Sequence similarities to the type strains of the other recognized species were less than 93.04 %. Strain GJSW-6(T) was found to contain Q-8 as the predominant ubiquinone and C16:0, summed feature 3 (C16:1 ω7c and/or C16:1 ω6c) and C18:1 ω7c as the major fatty acids. The polar lipid profile of strain GJSW-6(T) containing phosphatidylethanolamine and phosphatidylglycerol as major components was similar to those of the type strains of A. albus and A. gilvus. The DNA G+C content of strain GJSW-6(T) was determined to be 45.3 mol% and its mean DNA-DNA relatedness value with A. albus JCM 21469(T) was 19 %. Differential phenotypic properties, together with the phylogenetic and genetic distinctiveness, revealed that strain GJSW-6(T) is separated from two Agarivorans species. On the basis of the data presented, strain GJSW-6(T) is considered to represent a novel species of the genus Agarivorans, for which the name Agarivorans litoreus sp. nov. is proposed. The type strain is GJSW-6(T) (= KCTC 42116(T) = NBRC 110444(T)). An emended description of the genus Agarivorans is also proposed.

Comparative analysis of 16S rRNA signature sequences of the genus Idiomarina and Idiomarina woesei sp. nov., a novel marine bacterium isolated from the Andaman Sea.

A Gram-negative, short rod, aerobic bacterium, designated W11(T), was isolated from seawater. Heterotrophic growth was observed at 10-45 °C and pH 6-10. Optimal growth was observed at 30-37 °C and pH 7-9. It can grow in the presence of 0.5-12% NaCl (w/v), and the optimal NaCl required for growth was 5-6%. 16S rRNA gene sequence similarity revealed that strain W11(T) clustered within the radiation of the genus Idiomarina and showed 99.24% similarity with Idiomarina donghaiensis JCM 15533(T), 97.64% with Idiomarina marina JCM 15083(T), 97.37% with Idiomarina tainanensis JCM 15084(T) and 97.16% with Idiomarina maritima JCM 15534(T). DNA-DNA similarities between strains W11(T) with other closely related strains were below 70%. Polar lipids included a phosphatidylgylycerol, a diphosphatidylglycerol, a phosphatidylethanolamine, an unidentified phosopholipid, two unidentified aminolipids and two unidentified lipids. DNA G + C content was 41.2 ± 0.1 mol%. Major fatty acids were iso-C15:0, iso-C17:0, iso-C17:1ω9c, C16:0, iso-C11:0 3OH and C16:1ω7c/C16:1ω7c. The isoprenoid ubiquinone was Q8. On the basis of the present polyphasic taxonomic study, strain W11(T) is considered to represent a novel species of the genus Idiomarina, for which the name Idiomarina woesei sp. nov. is proposed. The type strain is W11(T) (= DSM 27808(T) = JCM 19499(T) = LMG 27903(T)).

Isolation and algicidal characterization of Bowmanella denitrificans S088 against Chlorella vulgaris.

One strain of algicidal bacterium, named as S088, was isolated from the intestine of healthy sea cucumbers (Stichopus horrens) in the South China Sea. Based on the analysis of its biochemical characteristics and 16S rDNA gene sequence, S088 was identified as Bowmanella denitrificans. Importantly, the algicidal activity of S088 on Chlorella vulgaris was characterized in this study. The initial densities of bacterial and algal cell showed strong influence on the removal rates of chlorophyll a. When the strain S088 was cultured under a complete darkness condition at 30 °C, its algicidal activity reached the highest level. Furthermore, it was found that the filtered supernatant from bacterial cultures had full algicidal activity, suggesting that the secreted compounds from S088 are involved in the observed algicidal action of S088. Moreover, the algicidal compounds were heat tolerant and had no cytotoxicity against fish cells, indicating that S088 would have a promising application as a safe probiotics for S. horrens. Finally, this is the first report about the algicidal activities in B. denitrificans.

Colwellia meonggei sp. nov., a novel gammaproteobacterium isolated from sea squirt Halocynthia roretzi.

A Gram-negative, non-spore-forming, aerobic, motile and rod-shaped or ovoid bacterial strain, designated MA1-3(T), was isolated from a sea squirt (Halocynthia roretzi) collected from the South sea in South Korea. Strain MA1-3(T) was found to grow optimally at 25 °C, at pH 7.0-8.0 and in the presence of 2.0 % (w/v) NaCl. Phylogenetic trees based on 16S rRNA gene sequences revealed that strain MA1-3(T) fell within the clade comprising Colwellia species, clustering coherently with the type strains of Colwellia aestuarii, Colwellia polaris and Colwellia chukchiensis, showing sequence similarity values of 97.2, 96.4 and 95.6 %, respectively. It exhibited 16S rRNA gene sequence similarity values of 93.9-96.1 % to the type strains of the other Colwellia species. Strain MA1-3(T) was found to contain Q-8 as the predominant ubiquinone and C16:1 ω7c and/or C16:1 ω6c, C16:0 and C16:1 ω9c as the major fatty acids. The DNA G+C content of strain MA1-3(T) was determined to be 39.1 mol% and its mean DNA-DNA relatedness value with the type strain of C. aestuarii was 13 ± 5.4 %. The differential phenotypic properties, together with the phylogenetic and genetic distinctiveness, revealed that the novel strain is separated from other Colwellia species. On the basis of the data presented, strain MA1-3(T) is considered to represent a novel species of the genus Colwellia, for which the name Colwellia meonggei sp. nov. is proposed. The type strain is MA1-3(T) (=KCTC 32380(T) = CECT 8302(T)).

Glaciecola aquimarina sp. nov., a gammaproteobacterium isolated from coastal seawater.

A Gram-negative, aerobic, non-motile and ovoid or rod-shaped bacterial strain, GGW-M5(T), was isolated from seawater on the southern coast in Korea, and its taxonomic position was investigated by using a polyphasic approach. Strain GGW-M5(T) grew optimally at pH 7.0-8.0, at 30 °C and in the presence of 2 % (w/v) NaCl. A neighbour-joining phylogenetic tree based on 16S rRNA gene sequences revealed that strain GGW-M5(T) belonged to the genus Glaciecola, joining the cluster comprising the type strains of G. agarilytica, G. arctica, G. chathamensis, G. mesophila, G. polaris and G. psychrophila, with which it exhibited 16S rRNA gene sequence similarity values of 95.9-96.7 %. Strain GGW-M5(T) exhibited sequence similarity values of 93.2-94.8 % to the type strains of the other Glaciecola species. Strain GGW-M5(T) contained Q-8 as the predominant ubiquinone and C16:1 ω7c and/or iso-C15:0 2-OH, C16:0 and C14:0 2-OH as the major fatty acids. Major polar lipids were phosphatidylglycerol, phosphatidylethanolamine and diphosphatidylglycerol. The DNA G+C content was 42.4 mol%. Differential phenotypic properties, together with the phylogenetic distinctiveness, demonstrated that strain GGW-M5(T) could be distinguished from other Glaciecola species. On the basis of the data presented, strain GGW-M5(T) is considered to represent a novel species of the genus Glaciecola, for which the name Glaciecola aquimarina sp. nov. is proposed. The type strain is GGW-M5(T) (=KCTC 32108(T) = CCUG 62918(T)).

Microbulbifer marinus sp. nov. and Microbulbifer yueqingensis sp. nov., isolated from marine sediment.

Two Gram-negative, aerobic strains, Y215(T) and Y226(T), were isolated from sediment from Yueqing Bay, Zhejiang Province, China. The two novel strains were both positive for oxidase activity, nitrate reduction, and aesculin and casein decomposition, but negative for gelatin and tyrosine decomposition. Catalase activity, and starch and Tween 80 decomposition differed between the two strains. Cells of both novel strains were rod-shaped in young cultures and ovoid in older cultures. Optimum NaCl concentration and pH range for growth of both strains were 2.0-3.0% (w/v) and 7.0-8.0, respectively, whereas the optimum growth temperature for strain Y215(T) (25-30 °C) was lower than that for strain Y226(T) (30-37 °C). The genomic DNA G+C contents of strains Y215(T) and Y226(T) were 54.0 and 56.7 mol%, respectively. The major fatty acids in both isolates were iso-C(15:0) and iso-C(17:1)ω9c, which was also the case in the reference strains apart from Microbulbifer salipaludis, which possessed C(18:1)ω7c as the predominant fatty acid. The predominant isoprenoid quinone was Q-8 and the major polar lipids of both strains were phosphatidylethanolamine, phosphatidylglycerol and an unknown glycolipid. Both strains had highest 16S rRNA gene sequence similarity to members of the genus Microbulbifer. Strain Y215(T) was closely related to the type strains of Microbulbifer maritimus (97.6%) and Microbulbifer donghaiensis (97.5%), whereas strain Y226(T) was closely related to the type strain of M. salipaludis (97.6%). Phylogenetic analysis based on 16S rRNA gene sequences showed that strains Y215(T) and Y226(T) fell into two separate clusters. The DNA-DNA relatedness values of strain Y215(T) with M. maritimus TF-17(T) and M. donghaiensis CN85(T) were 34.1 and 32.8%, respectively, whereas that between strain Y226(T) and M. salipaludis SM-1(T) was 38.0%; these values are significantly lower than the threshold value for the delineation of bacterial species. On the basis of their distinct taxonomic characteristics, the two isolates represent two novel species of the genus Microbulbifer, for which the names Microbulbifer marinus sp. nov. and Microbulbifer yueqingensis sp. nov. are proposed; the type strains are Y215(T) (=CGMCC 1.10657(T)=JCM 17211(T)) and Y226(T) (=CGMCC 1.10658(T)=JCM 17212(T)), respectively.

Idiomarina aquimaris sp. nov., isolated from the reef-building coral Isopora palifera.

A bacterial strain designated SW15(T) was isolated from a sample of the reef-building coral Isopora palifera, collected in southern Taiwan. The novel strain was characterized using a polyphasic taxonomic approach. Cells of strain SW15(T) were Gram-negative, aerobic, light yellow, rod-shaped and motile by means of a single polar flagellum. In phylogenetic analyses based on 16S rRNA gene sequences, strain SW15(T) appeared to belong to the genus Idiomarina in the class Gammaproteobacteria and to be most closely related to Idiomarina homiensis PO-M2(T) (97.6% sequence similarity). Strain SW15(T) exhibited optimal growth between 20 and 30 °C, with NaCl between 3% and 4% (w/v) and at a pH value between 7 and 8. Predominant cellular fatty acids were iso-C(15:0) (31.1%), iso-C(17:0) (15.4%), iso-C(17:1)ω9c (10.0%) and C(16:0) (8.8%). The major respiratory quinone was ubiquinone Q-8. The polar lipid profile consisted of a mixture of phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylserine, an uncharacterized aminolipid and several uncharacterized phospholipids. The DNA G+C content was 51.1 mol%. The level of DNA-DNA relatedness between strain SW15(T) and Idiomarina homiensis PO-M2(T) was 42.6-56.5%. The results of physiological and biochemical tests allowed the clear phenotypic differentiation of the novel strain from established species of the genus Idiomarina. Based on the genotypic, phenotypic and chemotaxonomic data, strain SW15(T) represents a novel species in the genus Idiomarina, for which the name Idiomarina aquimaris sp. nov. is proposed, with SW15(T) (=LMG 25374(T)=BCRC 80083(T)) as the type strain.

Agarivorans gilvus sp. nov. isolated from seaweed.

A novel agarase-producing, non-endospore-forming marine bacterium, WH0801(T), was isolated from a fresh seaweed sample collected from the coast of Weihai, China. Preliminary characterization based on 16S rRNA gene sequence analysis showed that WH0801(T) shared 96.1  % similarity with Agarivorans albus MKT 106(T), the type species of the genus Agarivorans. A polyphasic taxonomic study was conducted and confirmed the phylogenetic affiliation of strain WH0801(T) to the genus Agarivorans. Isolate WH0801(T) produces light-yellow-pigmented colonies; cells are Gram-stain-negative, straight or curved rods, which are motile with a single polar flagellum. Strain WH0801(T) grew in 0.5-5  % NaCl, with optimum growth at 3  % NaCl, and its optimal pH and cultivation temperature were 8.4-8.6 and 28-32 °C, respectively. Data from biochemical tests, whole-cell fatty acid profiling, 16S rRNA gene sequence studies and DNA-DNA hybridization clearly indicated that isolate WH0801(T) represented a novel species within the genus Agarivorans, for which the name Agarivorans gilvus sp. nov. is proposed. The type strain of Agarivorans gilvus sp. nov. is WH0801(T) (=NRRL B-59247(T) =CGMCC 1.10131(T)).

Marinobacterium coralli sp. nov., isolated from mucus of coral (Mussismilia hispida).

A Gram-negative, aerobic bacterium, designated R-40509(T), was isolated from mucus of the reef builder coral (Mussismilia hispida) located in the São Sebastião Channel, São Paulo, Brazil. The strain was oxidase-positive and catalase-negative, and required Na(+) for growth. Its phylogenetic position was in the genus Marinobacterium and the closest related species were Marinobacterium sediminicola, Marinobacterium maritimum and Marinobacterium stanieri; the isolate exhibited 16S rRNA gene sequence similarities of 97.5-98.0 % with the type strains of these species. 16S rRNA gene sequence similarities with other type strains of the genus Marinobacterium were below 96 %. DNA-DNA hybridizations between strain R-40509(T) and the type strains of the phylogenetically closest species of the genus Marinobacterium revealed less than 70 % DNA-DNA relatedness, supporting the novel species status of the strain. Phenotypic characterization revealed that the strain was able to grow at 15-42 °C and in medium containing up to 9 % NaCl. The isolate could be differentiated from phenotypically related species by several features, including its ability to utilize d-alanine, l-alanine, bromosuccinic acid, ß-hydroxybutyric acid and α-ketovaleric acid, but not acetate or l-arabinose. It produced acetoin (Voges-Proskauer), but did not have esterase lipase (C8) or catalase activities. It possessed C(18 : 1)ω7c (35 %), summed feature 3 (iso-C(15 : 0) 2-OH and/or C(16 : 1)ω7c; 25 %) and C(16 : 0) (22 %) as major cellular fatty acids. The DNA G+C content was 58.5 mol%. The name Marinobacterium coralli sp. nov. is proposed to accommodate this novel isolate; the type strain is R-40509(T) (=LMG 25435(T) =CAIM 1449(T)).

Colwellia chukchiensis sp. nov., a psychrotolerant bacterium isolated from the Arctic Ocean.

A novel psychrotolerant bacterial strain, BCw111(T), was isolated from seawater samples from the Chukchi Sea in the Arctic Ocean. Cells of strain BCw111(T) were Gram-negative, motile, facultatively anaerobic, curved rods and were able to grow at 0-30 °C (optimum 23-25 °C). Strain BCw111(T) had Q-8 as the major respiratory quinone and contained iso-C(15 : 0) 2-OH and/or C(16 : 1)ω7c (28.13 %), C(16 : 0) (13.28 %) and C(17 : 1) (12.90 %) as the major cellular fatty acids. The genomic DNA G+C content was 41.3 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain BCw11(T) formed a distinct lineage within the genus Colwellia and exhibited the highest 16S rRNA gene sequence similarity with Colwellia polaris 537(T) (97.8 %) and Colwellia aestuarii SMK-10(T) (97.1 %). Based on phenotypic characteristics, phylogenetic analysis and DNA-DNA relatedness, a novel species, Colwellia chukchiensis sp. nov., is proposed. The type strain is BCw111(T) ( = CGMCC 1.9127(T)  = LMG 25329(T)  = DSM 22576(T)).