Structural basis for Na(+) transport mechanism by a light-driven Na(+) pump.

Krokinobacter eikastus rhodopsin 2 (KR2) is the first light-driven Na(+) pump discovered, and is viewed as a potential next-generation optogenetics tool. Since the positively charged Schiff base proton, located within the ion-conducting pathway of all light-driven ion pumps, was thought to prohibit the transport of a non-proton cation, the discovery of KR2 raised the question of how it achieves Na(+) transport. Here we present crystal structures of KR2 under neutral and acidic conditions, which represent the resting and M-like intermediate states, respectively. Structural and spectroscopic analyses revealed the gating mechanism, whereby the flipping of Asp116 sequesters the Schiff base proton from the conducting pathway to facilitate Na(+) transport. Together with the structure-based engineering of the first light-driven K(+) pumps, electrophysiological assays in mammalian neurons and behavioural assays in a nematode, our studies reveal the molecular basis for light-driven non-proton cation pumps and thus provide a framework that may advance the development of next-generation optogenetics.

Rubritalea profundi sp. nov., isolated from deep-seawater and emended description of the genus Rubritalea in the phylum Verrucomicrobia.

A Gram-stain-negative, short-rod, facultatively anaerobic, non-motile and red-pigmented bacterium, designated SAORIC-165T, was isolated from a deep-seawater sample collected from the Pacific Ocean. The 16S rRNA gene sequence analysis showed that strain SAORIC-165T was most closely related to Rubritalea marina Pol012T (95.7 % sequence similarity) and formed a robust phylogenetic clade with other species of the genus Rubritalea in the phylum Verrucomicrobia. Optimal growth of strain SAORIC-165T was observed at 10 °C, pH 7.0 and in the presence of 2.0-3.5 % (w/v) NaCl. The DNA G+C content of strain SAORIC-165T was 50.7 mol% and MK-9 was the predominant isoprenoid quinone. The major cellular fatty acids were summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c), iso-C14 : 0, anteiso-C15 : 0, C16 : 0 and C14 : 0. The major polar lipids constituted phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol and unidentified phospholipids and aminolipids. On the basis of the taxonomic data obtained in this study, it was concluded that strain SAORIC-165T represented a novel species of the genus Rubritalea, for which the name Rubritalea profundi sp. nov. is proposed. The type strain of Rubritalea profundi is SAORIC-165T (=NBRC 110691T=KCTC 52460T).

Structural Mechanism for Light-driven Transport by a New Type of Chloride Ion Pump, Nonlabens marinus Rhodopsin-3.

The light-driven inward chloride ion-pumping rhodopsin Nonlabens marinus rhodopsin-3 (NM-R3), from a marine flavobacterium, belongs to a phylogenetic lineage distinct from the halorhodopsins known as archaeal inward chloride ion-pumping rhodopsins. NM-R3 and halorhodopsin have distinct motif sequences that are important for chloride ion binding and transport. In this study, we present the crystal structure of a new type of light-driven chloride ion pump, NM-R3, at 1.58 Å resolution. The structure revealed the chloride ion translocation pathway and showed that a single chloride ion resides near the Schiff base. The overall structure, chloride ion-binding site, and translocation pathway of NM-R3 are different from those of halorhodopsin. Unexpectedly, this NM-R3 structure is similar to the crystal structure of the light-driven outward sodium ion pump, Krokinobacter eikastus rhodopsin 2. Structural and mutational analyses of NM-R3 revealed that most of the important amino acid residues for chloride ion pumping exist in the ion influx region, located on the extracellular side of NM-R3. In contrast, on the opposite side, the cytoplasmic regions of K. eikastus rhodopsin 2 were reportedly important for sodium ion pumping. These results provide new insight into ion selection mechanisms in ion pumping rhodopsins, in which the ion influx regions of both the inward and outward pumps are important for their ion selectivities.

Functional characterization of flavobacteria rhodopsins reveals a unique class of light-driven chloride pump in bacteria.

Light-activated, ion-pumping rhodopsins are broadly distributed among many different bacteria and archaea inhabiting the photic zone of aquatic environments. Bacterial proton- or sodium-translocating rhodopsins can convert light energy into a chemiosmotic force that can be converted into cellular biochemical energy, and thus represent a widespread alternative form of photoheterotrophy. Here we report that the genome of the marine flavobacterium Nonlabens marinus S1-08(T) encodes three different types of rhodopsins: Nonlabens marinus rhodopsin 1 (NM-R1), Nonlabens marinus rhodopsin 2 (NM-R2), and Nonlabens marinus rhodopsin 3 (NM-R3). Our functional analysis demonstrated that NM-R1 and NM-R2 are light-driven outward-translocating H(+) and Na(+) pumps, respectively. Functional analyses further revealed that the light-activated NM-R3 rhodopsin pumps Cl(-) ions into the cell, representing the first chloride-pumping rhodopsin uncovered in a marine bacterium. Phylogenetic analysis revealed that NM-R3 belongs to a distinct phylogenetic lineage quite distant from archaeal inward Cl(-)-pumping rhodopsins like halorhodopsin, suggesting that different types of chloride-pumping rhodopsins have evolved independently within marine bacterial lineages. Taken together, our data suggest that similar to haloarchaea, a considerable variety of rhodopsin types with different ion specificities have evolved in marine bacteria, with individual marine strains containing as many as three functionally different rhodopsins.

Genomic and metagenomic analysis of microbes in a soil environment affected by the 2011 Great East Japan Earthquake tsunami.

BACKGROUND: The Great East Japan Earthquake of 2011 triggered large tsunami waves, which flooded broad areas of land along the Pacific coast of eastern Japan and changed the soil environment drastically. However, the microbial characteristics of tsunami-affected soil at the genomic level remain largely unknown. In this study, we isolated microbes from a soil sample using general low-nutrient and seawater-based media to investigate microbial characteristics in tsunami-affected soil. RESULTS: As expected, a greater proportion of strains isolated from the tsunami-affected soil than the unaffected soil grew in the seawater-based medium. Cultivable strains in both the general low-nutrient and seawater-based media were distributed in the genus Arthrobacter. Most importantly, whole-genome sequencing of four of the isolated Arthrobacter strains revealed independent losses of siderophore-synthesis genes from their genomes. Siderophores are low-molecular-weight, iron-chelating compounds that are secreted for iron uptake; thus, the loss of siderophore-synthesis genes indicates that these strains have adapted to environments with high-iron concentrations. Indeed, chemical analysis confirmed the investigated soil samples to be rich in iron, and culture experiments confirmed weak cultivability of some of these strains in iron-limited media. Furthermore, metagenomic analyses demonstrated over-representation of denitrification-related genes in the tsunami-affected soil sample, as well as the presence of pathogenic and marine-living genera and genes related to salt-tolerance. CONCLUSIONS: Collectively, the present results would provide an example of microbial characteristics of soil disturbed by the tsunami, which may give an insight into microbial adaptation to drastic environmental changes. Further analyses on microbial ecology after a tsunami are envisioned to develop a deeper understanding of the recovery processes of terrestrial microbial ecosystems.

Rubrivirga profundi sp. nov., isolated from deep-sea water, and emended description of the genus Rubrivirga.

A Gram-staining-negative, rod-shaped, facultatively anaerobic, non-motile and pale-red-pigmented bacterium, designated SAORIC-476T, was isolated from deep-sea water from the Pacific Ocean. 16S rRNA gene sequence analyses showed that strain SAORIC-476T was most closely related to Rubrivirga marinaSAORIC-28T (96.8 % similarity) and formed a robust phylogenetic clade with Rubrivirga marinaof the family Rhodothermaceae. Optimal growth of strain SAORIC-476T was observed at 25 °C, pH 7.5 and in the presence of 3.0 % (w/v) NaCl. The DNA G+C content of strain SAORIC-476T was 66.2 mol%, and the sole isoprenoid quinone was MK-7. The predominant cellular fatty acids were summed feature 9 (iso-C17 : 1ω9c and/or 10-methyl C16 : 0), iso-C17 : 0, C17 : 1ω8c and iso-C15 : 0. The major polar lipids constituted phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, three unknown phospholipids and four unknown polar lipids. On the basis of taxonomic data obtained in this study, it was concluded that strain SAORIC-476T represents a novel species of the genus Rubrivirga, for which the name Rubrivirga profundi sp. nov. is proposed. The type strain of Rubrivirga profundi is SAORIC-476T (=NBRC 110607T=KACC 18401T).

Lentisphaera profundi sp. nov., isolated from deep-sea water.

A Gram-staining-negative, aerobic, non-motile, coccus-shaped bacterium, designated SAORIC-696T, was isolated from deep-sea water at a depth of 1700 m in the western North Pacific Ocean. Optimal growth of strain SAORIC-696T was observed at 15 °C, pH 7.0 and in the presence of 2 % (w/v) NaCl. Strain SAORIC-696T formed a robust phylogenetic clade with members of the genus Lentisphaera. The 16S rRNA gene sequence similarity showed that strain SAORIC-696T was most closely related to Lentisphaera marina (98.0 % similarity) and Lentisphaera araneosa (97.3 %). The DNA-DNA relatedness between SAORIC-696T and two species of the genus Lentisphaera was only 27-42 %. The DNA G+C content of strain SAORIC-696T was 43.1 mol% and predominant cellular fatty acids were C16 : 1ω9c (36.8 %), C14 : 0 (22.5 %) and C14 : 0 3-OH and/or iso-C16 : 1 I (10.8 %). Strain SAORIC-696T contained MK-7 as the only respiratory quinone. On the basis of taxonomic data collected in this study, it was concluded that strain SAORIC-696T represents a novel species of the genus Lentisphaera, for which the name Lentisphaera profundi sp. nov. is proposed, with the type strain SAORIC-696T ( = NBRC 110692T = KCTC 42681T).

Aurantivirga profunda gen. nov., sp. nov., isolated from deep-seawater, a novel member of the family Flavobacteriaceae.

A Gram-stain-negative, aerobic, proteorhodopsin-containing, orange, rod-shaped bacterium, designated SAORIC-234T, was isolated from deep seawater in the Pacific Ocean. 16S rRNA gene sequence analysis revealed that the strain could be affiliated with the family Flavobacteriaceae of the phylum Bacteroidetes and shared less than 94.6 % similarity with other species of the family with validly published names. The phenotypic characteristics of this novel isolate, such as growth properties and enzyme activities, could be differentiated from those of other species. The strain was non-motile, oxidase-positive and catalase-negative. The G+C content of the genomic DNA was determined to be 34.8 mol% and menaquinone-6 (MK-6) was the predominant isoprenoid quinone. The predominant fatty acids were iso-C15 : 0, iso-C15 : 1 G, iso-C16 : 0 3-OH, iso-C17 : 0 3-OH and iso-C15 : 0 3-OH. The major polar lipids comprised phosphatidylethanolamine, three unknown aminolipids and three unknown lipids. On the basis of the taxonomic data collected in this study, it was concluded that strain SAORIC-234T represents a novel genus and species in the family Flavobacteriaceae, for which the name Aurantivirga profunda gen. nov., sp. nov. is proposed. The type strain of the type species, Aurantivirga profunda sp. nov., is SAORIC-234T ( = NBRC 110606T = KACC 18400T).

Fabibacter misakiensis sp. nov., a marine bacterium isolated from coastal surface water.

A slightly curved-rod-shaped, pink-pigmented, Gram-stain-negative, aerobic bacterial strain with gliding motility, designated SK-8T, was isolated from coastal surface water of Misaki, Japan. Phylogenetic trees generated using 16S rRNA gene sequences revealed that strain SK-8T belonged to the genus Fabibacter and showed 96.0 % sequence similarity to the type strain of the most closely related species, Fabibacter pacificus DY53T. The novel isolate was phenotypically and physiologically different from previously described strains. The major cellular fatty acids were iso-C15 : 1 G, iso-C15 : 0 and iso-C17 : 0 3-OH. Major polar lipids were phosphatidylethanolamine, two aminophospholipids and an unidentified phospholipid. The DNA G+C content was 39.1 mol% and MK-7 was the only predominant isoprenoid quinone. On the basis of this taxonomic study employing a polyphasic approach, it was suggested that strain SK-8T represents a novel species of the genus Fabibacter, with the newly proposed name Fabibacter misakiensis sp. nov. The type strain is SK-8T ( = NBRC 110216T = KCTC 32969T).

Pelagitalea pacifica gen. nov., sp. nov., a new marine bacterium isolated from seawater.

A strictly aerobic, Gram-negative, beige-pigmented, short-rod-shaped, non-motile and chemoheterotrophic bacteria, designated K2-48(T) was isolated from seawater collected in the Western North Pacific Ocean near Japan. Preliminary analysis based on the 16S rRNA gene sequence revealed that the novel isolate was affiliated with the family Oceanospirillaceae within the class Gammaproteobacteria and that it showed the highest sequence similarity (93.7 %) to Neptunomonas qingdaonensis P10-2-4(T). The strain could be differentiated phenotypically from recognized members of the family Oceanospirillaceae. The major fatty acids of strain K2-48(T) were identified as summed feature 3 (C16:1 ω7c and/or iso-C15:0 2-OH) and C16:0 as defined by the MIDI system. The DNA G+C content was determined to be 43.2 mol%, the major respiratory quinone was identified as ubiquinone 9 and a polar lipid profile was present consisting of phosphatidylethanolamine, a phosphatidylglycerol and an unidentified phospolipid. On the basis of polyphasic taxonomic studies, it was concluded that strain K2-48(T) represents a novel genus sp. We propose the name Pelagitalea pacifica gen. nov., sp. nov. for this strain; its type strain is K2-48(T) (=KCCM 90119(T)).

Aureicoccus marinus gen. nov., sp. nov., a member of the family Flavobacteriaceae, isolated from seawater.

A coccoid and amorphous-shaped, non-gliding, proteorhodopsin-containing, yellow bacterium, designated strain SG-18(T), was isolated from seawater in the western North Pacific Ocean near Japan. The strain was Gram-stain-negative, obligately aerobic, heterotrophic and oxidase-positive. It hydrolysed aesculin but not DNA, urea, gelatin or agar. Growth occurred in the presence of 1-5 % NaCl, with optimum growth at 2 % NaCl. The strain grew at 15-37 °C with an optimum temperature of 25-30 °C. The DNA G+C content of the genomic DNA of strain SG-18(T) was 47.0 mol% (HPLC). The predominant isoprenoid quinone was MK-6, and major cellular fatty acids were iso-C15 : 1 G, iso-C15 : 0, iso-C15 : 0 3-OH. Phylogenetic trees generated by using 16S rRNA gene sequences revealed that strain SG-18(T) belonged to the family Flavobacteriaceae and showed 92.7 % sequence similarity to the most closely related species, Croceitalea eckloniae DOKDO 025(T). On the basis of phenotypic and phylogenetic features, strain SG-18(T) is classified as representing a novel species of a new genus within the family Flavobacteriaceae, for which the name Aureicoccus marinus gen. nov., sp. nov. is proposed. The type strain of the type species is SG-18(T) ( = NBRC 108814(T) = KCTC 23967(T)).

Rubrivirga marina gen. nov., sp. nov., a member of the family Rhodothermaceae isolated from deep seawater.

Two aerobic, Gram-stain-negative, pale-red-pigmented and rod-shaped bacterial strains, designated SAORIC-26 and SAORIC-28(T), were isolated from seawater (3000 m depth) from the Pacific Ocean. Phylogenetic analysis based on their 16S rRNA gene sequences revealed that the novel isolates could be affiliated with the family Rhodothermaceae of the class Cytophagia. Strains SAORIC-26 and SAORIC-28(T) shared 99.7% pairwise sequence similarity with each other and showed less than 92.6% similarity with other cultivated members of the class Cytophagia. The strains were found to be non-motile, oxidase-positive, catalase-negative and able to hydrolyse gelatin and aesculin. The DNA G+C contents were determined to be 64.8-65.8 mol% and MK-7 was the predominant menaquinone. Summed feature 9 (iso-C17:1ω9c and/or C16:0 10-methyl), summed feature 3 (C16:1ω6c and/or C16:1ω7c) and iso-C15:0 were found to be the major cellular fatty acids. On the basis of this taxonomic study using a polyphasic approach, it was concluded that strains SAORIC-26 and SAORIC-28(T) represent a novel species of a new genus in the family Rhodothermaceae, for which the name Rubrivirga marina gen. nov., sp. nov. is proposed. The type strain of the type species of is SAORIC-28(T) (=KCTC 23867(T)=NBRC 108816(T)). An additional strain of the species is SAORIC-26.

Bacterial response to glucose addition: growth and community structure in seawater microcosms from North Pacific Ocean.

Onboard microcosm experiments were conducted to assess how bacterial growth pattern and community structure changed by the addition of labile organic compound during the KH-14-2 cruise of R/V Hakuho Maru (Atmosphere and Ocean Research Institute, the University of Tokyo and JAMSTEC) in May-June 2014. Seawater samples were collected from the three diversified oceanic environments, Kuroshio Current, North Pacific Sub-polar Gyre (SPG), and North Pacific Sub-tropical Gyre (STG) in the western North Pacific Ocean, filtered, supplemented with glucose, and incubated at 23 ± 1 °C, ~ 4 °C, and 23 ± 1 °C, respectively. Untreated control microcosms were also maintained for all the sample types. Significant increases in cell counts and cell sizes were observed in Kuroshio Current and STG waters, whereas in SPG neither the counts nor the sizes changed, even after 120 h of incubation. At early stages of incubation, the classes Bacteroidia, Alphaproteobacteria, and Gammaproteobacteria were dominant in the Kuroshio Current and SPG samples, while the phyla Cyanobacteria and Proteobacteria in the STG samples. Over incubation periods between 60 and 96 h, some members of the class Gammaproteobacteria gradually dominated within which the genera Vibrio and Alteromonas became dominant in the Kuroshio Current and STG, respectively. No growth was detected for the microcosms with seawater from SPG, regardless of glucose amendment. It is concluded that depending on the environmental condition, certain different bacterial groups proliferated quickly and modified the community structures. Temperature significantly influenced the growth and succession, and ultimately the community structure of bacteria.

Diversity and functional analysis of proteorhodopsin in marine Flavobacteria.

Proteorhodopsin (PR) genes are widely distributed among marine prokaryotes and functions as light-driven proton pump when expressed heterologously in Escherichia coli, suggesting that light energy passing through PR may be substantial in marine environment. However, there are no data on PR proton pump activities in native marine bacteria. Here, we demonstrate light-driven proton pump activity (c. 124 H(+) PR(-1) min(-1) ) in recently isolated marine Flavobacteria. Among 75 isolates, 38 possessed the PR gene. Illumination of cell suspensions from all eight tested strains in five genera triggered marked pH drops. The action spectrum of proton pump activity closely matched the spectral distribution of the sea surface green light field. Addition of hydroxylamine to a solubilized membrane fraction shifted the spectrum to a form characteristic of PR photobleached into retinal oxime, indicating that PRs in flavobacterial cell membranes transform the photon dose in incident radiation into energy in the form of membrane potential. Our results revealed that PR-mediated proton transport can create the sufficient membrane potential for the ATP synthesis in native flavobacterial cells.

Aureitalea marina gen. nov., sp. nov., a member of the family Flavobacteriaceae, isolated from seawater.

An irregular rod-shaped, non-gliding, yellow-pigmented bacterium was isolated from seawater from the western North Pacific Ocean near Japan. The strain, designated S1-66T, was Gram-negative, obligately aerobic, heterotrophic and oxidase-positive. Growth occurred in the presence of 1-4 % NaCl, with optimum growth at 2 % NaCl. The strain grew at 15-30 °C, with optimum growth at 20-25 °C. The G+C content of genomic DNA was 48.1 mol% (HPLC). The predominant isoprenoid quinone was MK-6 and the major cellular fatty acids were iso-C15:0 (26.4 %), iso-C15:1 (20.3 %) and iso-C17:0 3-OH (14.2 %). Phylogenetic trees generated by using 16S rRNA gene sequences revealed that strain S1-66T belongs to the family Flavobacteriaceae and showed 94.2 % sequence similarity to the most closely related type strain, Ulvibacter antarcticus IMCC3101T. On the basis of phenotypic and phylogenetic features, S1-66T is classified in a novel genus and species within the family Flavobacteriaceae, for which the name Aureitalea marina gen. nov., sp. nov. is proposed. The type strain of Aureitalea marina is S1-66T (=NBRC 107741T=KCTC 23434T).

Halioglobus japonicus gen. nov., sp. nov. and Halioglobus pacificus sp. nov., members of the class Gammaproteobacteria isolated from seawater.

Two coccoid, non-motile bacteria were isolated from seawater in the north-western Pacific Ocean near Japan. The two strains, designated S1-36(T) and S1-72(T), were Gram-negative, obligately aerobic, heterotrophic and catalase-negative. They were able to reduce nitrate to nitrogen. Both strains required NaCl for growth, with optimum growth in 2% NaCl, and grew at 15-30 °C, with optimum growth at 20-25 °C. Genomic DNA G+C contents of strains S1-36(T) and S1-72(T) were 59.6 and 59.4 mol%, respectively. The predominant isoprenoid quinone was Q-8 and major cellular fatty acids were C(16:1)ω7c, C(18:1)ω7c and C(17:1)ω8c. Analyses of 16S rRNA gene sequences revealed that strains S1-36(T) and S1-72(T) were related to each other (96.1% sequence similarity) and both strains showed 92.3-94.7% sequence similarity with members of the genus Haliea. On the basis of phenotypic and phylogenetic features, strains S1-36(T) and S1-72(T) should be classified as representatives of two novel species in a new genus, Halioglobus gen. nov., within the class Gammaproteobacteria. The names proposed are Halioglobus japonicus sp. nov., the type species of the genus, with S1-36(T) ( = NBRC 107739(T) = KCTC 23429(T)) as type strain, and Halioglobus pacificus sp. nov., with S1-72(T) ( = NBRC 107742(T) = KCTC 23430(T)) as type strain.

Vibrio jasicida sp. nov., a member of the Harveyi clade, isolated from marine animals (packhorse lobster, abalone and Atlantic salmon).

Six isolates of a facultatively anaerobic bacterium were recovered in culture from marine invertebrates and vertebrates, including packhorse lobster (Jasus verreauxi), abalone (Haliotis sp.) and Atlantic salmon (Salmo salar), between 1994 and 2002. The bacteria were Gram-negative, rod-shaped and motile by means of more than one polar flagellum, oxidase-positive, catalase-positive and able to grow in the presence of 0.5-8.0% NaCl (optimum 3.0-6.0%) and at 10-37 °C (optimum 25-30 °C). On the basis of 16S rRNA gene sequence analysis and multilocus sequence analysis (MLSA) using five loci (2443 bp; gyrB, pyrH, ftsZ, mreB and gapA), the closest phylogenetic neighbours of strain TCFB 0772(T) were the type strains of Vibrio communis (99.8 and 94.6 % similarity, respectively), Vibrio owensii (99.8 and 94.1%), Vibrio natriegens (99.4 and 88.8%), Vibrio parahaemolyticus (99.4 and 90.3%), Vibrio rotiferianus (99.2 and 94.4%), Vibrio alginolyticus (99.1 and 89.3%) and Vibrio campbellii (99.1 and 92.3%). DNA-DNA hybridization confirmed that the six isolates constitute a unique taxon that is distinct from other known species of Vibrio. In addition, this taxon can be readily differentiated phenotypically from other Vibrio species. The six isolates therefore represent a novel species, for which the name Vibrio jasicida sp. nov. is proposed; the novel species is represented by the type strain TCFB 0772(T) ( = JCM 16453(T)  = LMG 25398(T)) (DNA G+C content 45.9 mol%) and reference strains TCFB 1977 ( = JCM 16454) and TCFB 1000 ( = JCM 16455).

Nonlabens marinus [corrected] sp. nov., a novel member of the Flavobacteriaceae isolated from the Pacific Ocean.

Two aerobic, Gram-negative, orange pigmented and irregular rod-shaped bacteria, designated S1-05 and S1-08(T), were isolated from seawater from the Pacific Ocean. Phylogenetic analysis based on their 16S rRNA gene sequences revealed that the novel isolates could be affiliated with the genus Nonlabens of the family Flavobacteriaceae. The strains S1-05 and S1-08(T) shared 100 % pairwise sequences similarity with each other and showed less than 96.8 % similarity with the cultivated members of the genus Nonlabens. The novel isolates are phenotypically and physiologically different from strains described previously. The strains were found to be non-motile, oxidase positive, catalase positive and hydrolyzed gelatin and aesculin. The G+C contents of the DNA were determined to 41.4 and 41.7 mol% and MK-6 the predominant menaquinone. Anteiso-C15:0 and iso-C15:0 were found to be the major two cellular fatty acids. On the basis of polyphasic taxonomic studies, it was concluded that strains S1-05 and S1-08(T) represent a novel species within the genus Nonlabens, for which the name Nonlabens marina sp. nov. is proposed. The type strain of N. marina is S1-08(T) (=KCTC 23432(T) = NBRC 107738(T)).

Rubricoccus marinus gen. nov., sp. nov., of the family 'Rhodothermaceae', isolated from seawater.

A coccoid- and amorphous-shaped, non-gliding, reddish bacterium, designated SG-29(T), was isolated from seawater in the western North Pacific Ocean near Japan. The strain was Gram-stain-negative, obligately aerobic, heterotrophic and catalase-positive. Nitrate was reduced to nitrogen and acid was produced from aesculin, turanose, 2-keto-gluconate and arabinose. Growth occurred with 1-5 % NaCl (optimum 2 % NaCl) and at 5-37 °C (optimum 20-30 °C). The G+C content of genomic DNA was 68.9 mol% (HPLC). The predominant isoprenoid quinone was MK-7 and the major cellular fatty acids (>10 %) were iso-C17:1ω9c, C17:1ω8c and iso-C17:0. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain SG-29(T) belonged to the phylum Bacteroidetes. The most closely related strain was Rhodothermus obamensis JCM 9785(T), with which the isolate exhibited 86.1 % 16S rRNA gene sequence similarity. On the basis of phenotypic and phylogenetic features, strain SG-29(T) is classified in a novel genus and species within the family 'Rhodothermaceae', for which the name Rubricoccus marinus gen. nov., sp. nov. ( = NBRC 107124(T)  = KCTC 23197(T)) is proposed.

Halomarina oriensis gen. nov., sp. nov., a halophilic archaeon isolated from a seawater aquarium.

A novel halophilic archaeon, strain KeC-11(T), was isolated from a seawater aquarium at the Ocean Research Institute, University of Tokyo, Japan. The strain was aerobic, Gram-negative and chemo-organotrophic, growing optimally at 37 °C, at pH 7.0-8.0 and in 2.7 M (16 %) NaCl. The strain required at least 10 mM magnesium ions for growth. Cells of strain KeC-11(T) were non-motile and generally irregular coccoids or discoids. The DNA G+C content of the isolate was 67.7 mol%. Phylogenetic tree reconstructions indicated that it was distantly related to the other recognized members of the family Halobacteriaceae, with the closest relative being Natronomonas pharaonis Gabara(T) (91 % sequence similarity). The strain contained C(20)C(20) and C(20)C(25) diether derivatives of phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, a glycolipid chromatographically identical to the glycosyl-mannosyl-glucosyl diether (TGD-2) and at least one unidentified glycolipid. Phenotypic characterization and phylogenetic data support the placement of isolate KeC-11(T) in a novel species in a new genus within the family Halobacteriaceae, for which the name Halomarina oriensis gen. nov., sp. nov. is proposed; the type strain is KeC-11(T) ( = JCM 16495(T)  = KCTC 4074(T)).