Unlocking bacterial potential to reduce farmland N2O emissions.

Farmed soils contribute substantially to global warming by emitting N2O (ref. 1), and mitigation has proved difficult2. Several microbial nitrogen transformations produce N2O, but the only biological sink for N2O is the enzyme NosZ, catalysing the reduction of N2O to N2 (ref. 3). Although strengthening the NosZ activity in soils would reduce N2O emissions, such bioengineering of the soil microbiota is considered challenging4,5. However, we have developed a technology to achieve this, using organic waste as a substrate and vector for N2O-respiring bacteria selected for their capacity to thrive in soil6-8. Here we have analysed the biokinetics of N2O reduction by our most promising N2O-respiring bacterium, Cloacibacterium sp. CB-01, its survival in soil and its effect on N2O emissions in field experiments. Fertilization with waste from biogas production, in which CB-01 had grown aerobically to about 6 × 109 cells per millilitre, reduced N2O emissions by 50-95%, depending on soil type. The strong and long-lasting effect of CB-01 is ascribed to its tenacity in soil, rather than its biokinetic parameters, which were inferior to those of other strains of N2O-respiring bacteria. Scaling our data up to the European level, we find that national anthropogenic N2O emissions could be reduced by 5-20%, and more if including other organic wastes. This opens an avenue for cost-effective reduction of N2O emissions for which other mitigation options are lacking at present.

Transient Near-UV Absorption of the Light-Driven Sodium Pump Krokinobacter eikastus Rhodopsin 2: A Spectroscopic Marker for Retinal Configuration.

We report a transient signature in the near-UV absorption of Krokinobacter eikastus rhodopsin 2 (KR2), which spans from the femtosecond up to the millisecond time scale. The signature rises with the all-trans to 13-cis isomerization of retinal and decays with the reisomerization to all-trans in the late photocycle, making it a promising marker band for retinal configuration. Hybrid quantum mechanics/molecular mechanics simulations show that the near-UV absorption signal corresponds to an S0 → S3 and/or an S0 → S5 transition, which is present in all photointermediates. These transitions exhibit a negligible spectral shift by the altering protein environment, in contrast to the main absorption band. This is rationalized by the extension of the transition densities that omits the Schiff base nitrogen. Further characterization and first steps into possible optogenetic applications were performed with near-UV quenching experiments of an induced photostationary state, yielding an ultrafast regeneration of the parent state of KR2.

Cryostabilization of the Cell Membrane of a Psychrotolerant Bacteria via Homeoviscous Adaptation.

Homeoviscous adaptation (maintenance of a critical balance between the saturated and unsaturated lipids) of the cell membrane of psychrotolerant bacteria is essential to protect them against freeze-thaw cycle. But how does the homeoviscous adaptation protect the cell membrane during cold stress? In this Letter, we answer this question using a coarse-grained molecular dynamics simulation technique. On the basis of the reported fatty acid profiles of psychrotolerant bacteria at different temperatures, multiple lipid membranes are simulated at a wide range of temperatures between 250 and 300 K. We explicate how the homeoviscous adaptation minimizes the effect of cold stress on the structure and fluidity of the membrane. Partial freezing of the saturated lipid domain occurs with the self-aggregation of saturated and unsaturated lipids near the melting temperature of the unadapted lipid membrane. The gel-like phase provides necessary local packing density that can be sensed by sensor proteins responsible for the homeoviscous adaptation.

Recurrent symbiont recruitment from fungal parasites in cicadas.

Diverse insects are associated with ancient bacterial symbionts, whose genomes have often suffered drastic reduction and degeneration. In extreme cases, such symbiont genomes seem almost unable to sustain the basic cellular functioning, which comprises an open question in the evolution of symbiosis. Here, we report an insect group wherein an ancient symbiont lineage suffering massive genome erosion has experienced recurrent extinction and replacement by host-associated pathogenic microbes. Cicadas are associated with the ancient bacterial co-obligate symbionts Sulcia and Hodgkinia, whose streamlined genomes are specialized for synthesizing essential amino acids, thereby enabling the host to live on plant sap. However, our inspection of 24 Japanese cicada species revealed that while all species possessed Sulcia, only nine species retained Hodgkinia, and their genomes exhibited substantial structural instability. The remaining 15 species lacked Hodgkinia and instead harbored yeast-like fungal symbionts. Detailed phylogenetic analyses uncovered repeated Hodgkinia-fungus and fungus-fungus replacements in cicadas. The fungal symbionts were phylogenetically intermingled with cicada-parasitizing Ophiocordyceps fungi, identifying entomopathogenic origins of the fungal symbionts. Most fungal symbionts of cicadas were uncultivable, but the fungal symbiont of Meimuna opalifera was cultivable, possibly because it is at an early stage of fungal symbiont replacement. Genome sequencing of the fungal symbiont revealed its metabolic versatility, presumably capable of synthesizing almost all amino acids, vitamins, and other metabolites, which is more than sufficient to compensate for the Hodgkinia loss. These findings highlight a straightforward ecological and evolutionary connection between parasitism and symbiosis, which may provide an evolutionary trajectory to renovate deteriorated ancient symbiosis via pathogen domestication.

Ascidiimonas aurantiaca gen. nov., sp. nov., a member of Flavobacteriaceae isolated from a sea squirt.

A Gram-stain negative, strictly aerobic, chemoheterotrophic, tangerine orange pigmented, curved-rod shaped bacterium, designated N5DA8-2C(T), was isolated from a sea squirt by use of a bait-streaked agar technique. Phylogenetic analysis based on the 16S rRNA gene sequence indicated that the novel marine strain is affiliated with the family Flavobacteriaceae of the phylum Bacteroidetes and that it shared high (92.6 %) sequence similarity with Frondibacter aureus A5Q-67(T). The strain could be differentiated phenotypically from the related members of the family Flavobacteriaceae. The major fatty acids of strain N5DA8-2C(T) were iso-C15:1 G, iso-C17:0 3-OH, iso-C15:0 and C16:1 ω7c and/or C16:1 ω6c. A polar lipid profile was present consisting of phosphatidylethanolamine and three unidentified amino lipids. The DNA G+C content of the strain was determined to be 41 mol% and the major respiratory quinone was identified as menaquinone 6 (MK-6). From the distinct phylogenetic position and combination of genotypic and phenotypic characteristics, the strain is considered to represent a novel genus in the family Flavobacteriaceae, for which the name Ascidiimonas aurantiaca gen. nov., sp. nov. is proposed. The type strain of A. aurantiaca gen. nov., sp. nov. is N5DA8-2C(T) (= KCTC 32992(T) = NBRC 110020(T)).

Interactions of the algicidal bacterium Kordia algicida with diatoms: regulated protease excretion for specific algal lysis.

Interactions of planktonic bacteria with primary producers such as diatoms have great impact on plankton population dynamics. Several studies described the detrimental effect of certain bacteria on diatoms but the biochemical nature and the regulation mechanism involved in the production of the active compounds remained often elusive. Here, we investigated the interactions of the algicidal bacterium Kordia algicida with the marine diatoms Skeletonema costatum, Thalassiosira weissflogii, Phaeodactylum tricornutum, and Chaetoceros didymus. Algicidal activity was only observed towards the first three of the tested diatom species while C. didymus proved to be not susceptible. The cell free filtrate and the >30 kDa fraction of stationary K. algicida cultures is fully active, suggesting a secreted algicidal principle. The active supernatant from bacterial cultures exhibited high protease activity and inhibition experiments proved that these enzymes are involved in the observed algicidal action of the bacteria. Protease mediated interactions are not controlled by the presence of the alga but dependent on the cell density of the K. algicida culture. We show that protease release is triggered by cell free bacterial filtrates suggesting a quorum sensing dependent excretion mechanism of the algicidal protein. The K. algicida / algae interactions in the plankton are thus host specific and under the control of previously unidentified factors.

Biofilm-forming capacity, surface hydrophobicity and aggregation characteristics of Myroides odoratus isolated from South African Oreochromis mossambicus fish.

AIMS: Although Myroides spp. are primarily isolated from clinical sources, they have also been isolated from freshwater fish, stainless steel weldment and catheter biofilms. The ability of these nonmotile isolates to adhere to surfaces and the role of hydrophobicity and autoaggregation were investigated. METHODS: Adherence of Myroides odoratus isolates from tilapia was investigated using microtitre adherence assays under varying environmental conditions. Hydrophobicity, aggregation and coaggregation were measured quantitatively. Biofilm structures were investigated using flow cells and microscopy. RESULTS AND CONCLUSIONS: Myroides odoratus isolates were strongly adherent in both nutrient-poor and -rich media at room temperature and nutrient-rich medium at 37 degrees C. Isolates appeared hydrophilic, while autoaggregation indices ranged from 7% to 24.8%. Statistically significant positive correlations were observed between biofilm formation and autoaggregation. Strong coaggregation interactions were observed with several Gram-positive organisms, as well as with Listeria spp. In flow cells, M. odoratus formed an overlying carpet, with knitted chains of L. monocytogenes cells situated underneath attached to the perspex flow cell surface. SIGNIFICANCE AND IMPACT OF STUDY: Myroides odoratus biofilm formation was influenced by temperature variation rather than altered nutrient levels. The association of Myroides spp. with Listeria spp. isolates suggests potential association in biofilm structures when these bacteria colonize biotic and/or abiotic surfaces.

Salegentibacter catena sp. nov., isolated from sediment of the South China Sea, and emended description of the genus Salegentibacter.

A novel marine bacterial strain, HY1T, was isolated from sediment of the South China Sea. The strain was aerobic and heterotrophic and formed saffron yellow-pigmented colonies on marine agar 2216. Cells were non-motile, Gram-negative rods, frequently occurring in chains. BLASTN searches revealed that the 16S rRNA gene sequence of strain HY1T showed high similarity with those of members of the genera Gillisia (91.7-93.8 %) and Salegentibacter (92.6-93.5 %). Phylogenetic analysis based on 16S rRNA gene sequences showed that the strain clustered with members of both Salegentibacter and Gillisia and phylogenetic trees constructed using three different methods (neighbour-joining, maximum-parsimony and minimum-evolution) indicated that strain HY1T clustered more frequently with members of the genus Salegentibacter. The DNA G+C content of strain HY1T was 44.4 mol% and its major cellular fatty acids (>or=5 % of the total fatty acids) were iso-15 : 1 (5.0 %), iso-15 : 0 (6.8 %), anteiso-15 : 0 (6.4 %), 15 : 0 (10.4 %), iso-16 : 0 (13.5 %), summed feature 3 (comprising iso-15 : 0 2-OH and/or 16 : 1omega7c; 6.3 %), iso-17 : 0 3-OH (5.2 %) and 17 : 0 2-OH (5.0 %). Cells contained menaquinone 6. Based on the phylogenetic and phenotypic analyses, strain HY1T should be classified as representing a novel species within the genus Salegentibacter, for which the name Salegentibacter catena sp. nov. is proposed. The type strain is HY1T (=CGMCC 1.6101T=JCM 14015T). Based on this study and on previously described Salegentibacter species, an emended description of the genus Salegentibacter is given.

Sediminibacter furfurosus gen. nov., sp. nov. and Gilvibacter sediminis gen. nov., sp. nov., novel members of the family Flavobacteriaceae.

Two Gram-negative, chemoheterotrophic, non-motile strains, Mok-1-36T and MAOS-86T, were isolated from marine-sediment samples collected from the coasts of Okinawa island and the city of Odawara in Japan, respectively. Phylogenetic studies based on 16S rRNA gene sequences indicated that Mok-1-36T and MAOS-86T were members of the family Flavobacteriaceae, clustering with members of the genera Ulvibacter and Vitellibacter, respectively. Strains Mok-1-36T and MAOS-86T shared pairwise 16S rRNA gene sequence similarities of 93.5 and 89.1 % with the type strains of Ulvibacter litoralis and Vitellibacter vladivostokensis, respectively. Phylogenetic distinctiveness and phenotypic differences from their phylogenetic neighbours indicated that these strains represent two novel species and genera within the family Flavobacteriaceae, for which the names Sediminibacter furfurosus gen. nov., sp. nov. (MAOS-86T) and Gilvibacter sediminis gen. nov., sp. nov. (Mok-1-36T) are proposed. The type strain of Sediminibacter furfurosus is MAOS-86T (=NBRC 101622T=CIP 109285T) and the type strain of Gilvibacter sediminis is Mok-1-36T (=NBRC 101626T=CIP 109286T).

Quantifying substrate uptake by individual cells of marine bacterioplankton by catalyzed reporter deposition fluorescence in situ hybridization combined with microautoradiography.

Catalyzed reporter deposition fluorescence in situ hybridization combined with microautoradiography (MICRO-CARD-FISH) is increasingly being used to obtain qualitative information on substrate uptake by individual members of specific prokaryotic communities. Here we evaluated the potential for using this approach quantitatively by relating the measured silver grain area around cells taking up (3)H-labeled leucine to bulk leucine uptake measurements. The increase in the silver grain area over time around leucine-assimilating cells of coastal bacterial assemblages was linear during 4 to 6 h of incubation. By establishing standardized conditions for specific activity levels and concomitantly performing uptake measurements with the bulk community, MICRO-CARD-FISH can be used quantitatively to determine uptake rates on a single-cell level. Therefore, this approach allows comparisons of single-cell activities for bacterial communities obtained from different sites or growing under different ecological conditions.

Tenacibaculum aestuarii sp. nov., isolated from a tidal flat sediment in Korea.

A novel Tenacibaculum-like bacterial strain, SMK-4(T), was isolated from a tidal flat sediment in Korea. Strain SMK-4(T) was Gram-negative, pale yellow-pigmented and rod-shaped. It grew optimally at 30-37 degrees C and in the presence of 2-3 % (w/v) NaCl. It contained MK-6 as the predominant menaquinone and iso-C(15 : 0), iso-C(16 : 0) 3-OH and C(16 : 1)omega7c and/or iso-C(15 : 0) 2-OH as the major fatty acids (>10 % of total fatty acids). The DNA G+C content was 33.6 mol%. Phylogenetic trees based on 16S rRNA gene sequences showed that strain SMK-4(T) fell within the evolutionary radiation encompassed by the genus Tenacibaculum. Strain SMK-4(T) exhibited 16S rRNA gene sequence similarity levels of 95.2-98.6 % with respect to the type strains of recognized Tenacibaculum species. DNA-DNA relatedness levels and differential phenotypic properties made it possible to categorize strain SMK-4(T) as a species that is separate from previously described Tenacibaculum species. On the basis of phenotypic properties and phylogenetic and genetic distinctiveness, strain SMK-4(T) (=KCTC 12569(T)=JCM 13491(T)) should be classified as a novel Tenacibaculum species, for which the name Tenacibaculum aestuarii sp. nov. is proposed.

Mariniflexile gromovii gen. nov., sp. nov., a gliding bacterium isolated from the sea urchin Strongylocentrotus intermedius.

A marine bacterium, designated strain KMM 6038(T), was subjected to taxonomic analysis via a polyphasic approach. Cells of the strain were heterotrophic, orange-pigmented, Gram-negative and motile by means of gliding. 16S rRNA gene sequence analysis indicated that strain KMM 6038(T) was closely related to the type species of the genera Algibacter and Yeosuana, members of the family Flavobacteriaceae, with sequence similarities of 93.8 and 93.6 % to the respective type strains. However, several chemotaxonomic and phenotypic characteristics, such as the cellular fatty acid profile (iso-C(15 : 0), anteiso-C(15 : 0), iso-C(15 : 1), C(15 : 0), C(15 : 1)omega6c, iso-C(15 : 0) 3-OH and iso-C(17 : 0) 3-OH) and the low G+C content of the DNA (35.7 mol%), indicated that the strain should be separated from these two genera. From the results of phenotypic, genotypic, chemotaxonomic and phylogenetic analyses, the bacterium should be classified as representing a novel genus and species, for which the name Mariniflexile gromovii gen. nov., sp. nov. is proposed. The type strain of Mariniflexile gromovii is KMM 6038(T) (=KCTC 12570(T)=LMG 22578(T)).

Reclassification of [Flavobacterium] ferrugineum as Terrimonas ferruginea gen. nov., comb. nov., and description of Terrimonas lutea sp. nov., isolated from soil.

Strain DY(T), which was isolated from garden soil in Japan, was subjected to a polyphasic taxonomic study. Sequence analysis of the 16S rRNA gene and the GyrB protein revealed that the closest relative of strain DYT was [Flavobacterium] ferrugineum Sickles and Shaw 1934, with 94.8 and 90.1 % similarity, respectively. The two strains had similar chemotaxonomic characteristics, with menaquinone 7 as the major quinone system, 47.2-48.9 mol% DNA G+C content and 15 : 0 iso, 15 : 1 iso, 17 : 0 iso 3-OH and summed feature 3 as the major fatty acids. Based on genotypic and phenotypic characteristics, [Flavobacterium] ferrugineum IAM 15098T could be clearly differentiated from other members of the genus Flavobacterium. Strain DYT and [Flavobacterium] ferrugineum IAM 15098T could be easily distinguished from neighbouring taxa by morphological features (non-motile, non-gliding and non-filamentous single cells). Therefore, it is proposed that [Flavobacterium] ferrugineum IAM 15098T and strain DYT represent two separate species of a new genus, Terrimonas gen. nov., with the names Terrimonas ferruginea comb. nov. (type species; type strain IAM 15098T=ATCC 13524T) and Terrimonas lutea sp. nov. (type strain DYT=IAM 15284T=CCTCC AB205006T), respectively.

Dokdonia donghaensis gen. nov., sp. nov., isolated from sea water.

Two Gram-negative, non-motile, non-spore-forming, slightly halophilic bacterial strains, DSW-1T and DSW-21, were isolated from sea water and subjected to a polyphasic taxonomic study. They grew optimally at 30 degrees C and in the presence of 2 % (w/v) NaCl. Strains DSW-1T and DSW-21 were characterized chemotaxonomically as containing MK-6 as the predominant menaquinone and iso-C15 : 0, iso-C17 : 0 3-OH and iso-C15 : 1 as the major fatty acids. Their DNA G+C content was 38 mol%. Strains DSW-1T and DSW-21 exhibited four nucleotide differences in their 16S rRNA gene sequences and possessed a mean DNA-DNA relatedness level of 78 %. Phylogenetic analyses based on 16S rRNA gene sequences revealed that strains DSW-1T and DSW-21 formed a distinct lineage within the family Flavobacteriaceae. The 16S rRNA gene sequences of strains DSW-1T and DSW-21 had similarity levels of less than 92 x 2 % to the sequences of other members of the family Flavobacteriaceae. There were some differences in phenotypic properties between the two strains and Cellulophaga species, the nearest phylogenetic neighbours. On the basis of phenotypic, phylogenetic and genetic data, strains DSW-1T (=KCTC 12391T=DSM 17200T) and DSW-21 were classified in a novel genus and species, Dokdonia donghaensis gen. nov., sp. nov.

Polaribacter butkevichii sp. nov., a novel marine mesophilic bacterium of the family Flavobacteriaceae.

A novel heterotrophic, yellow pigmented, aerobic, Gram-negative, nonmotile, oxidase- and catalase-positive bacterium KMM 3,938(T) was isolated from sea water collected in the Sea of Japan, Russia. The strain grew at mesophilic temperature range, and required the presence of NaCl for growth. 16S rRNA gene sequence analysis revealed that strain KMM 3,938(T) is a member of the family Flavobacteriaceae. The predominant fatty acids were C13:0 iso, C14:0 iso, C15:0 iso, C15:0, C15:1Delta6, 3OH-C15:0:3 iso, and 3OH-C15:0. The G + C content of the DNA of KMM 3938(T) was 32.4 mol%. On the basis of phenotypic, chemotaxonomic, genotypic, and phylogenetic characteristics, the novel bacterium was assigned to the genus Polaribacter as Polaribacter butkevichii sp. nov. The type strain is KMM 3938(T )(= KCTC 12100(T) = CCUG 48005(T)).

Muricauda flavescens sp. nov. and Muricauda aquimarina sp. nov., isolated from a salt lake near Hwajinpo Beach of the East Sea in Korea, and emended description of the genus Muricauda.

Four Gram-negative, non-spore-forming, slightly halophilic rods (strains SW-62(T), SW-74, SW-63(T) and SW-72) with appendages were isolated from a salt lake near Hwajinpo Beach on the East Sea in Korea, and subjected to a polyphasic taxonomic analysis. Phylogenetic analyses based on 16S rRNA gene sequences showed that strains SW-62(T), SW-74, SW-63(T) and SW-72 formed a coherent cluster with Muricauda ruestringensis. Strains SW-62(T) and SW-74 had the same 16S rRNA gene sequence, as did strains SW-63(T) and SW-72. The level of 16S rRNA gene sequence similarity between strains SW-62(T) and SW-63(T) was 97.0 %. Strains SW-62(T) and SW-63(T) exhibited 16S rRNA gene similarity levels of 96.5 and 98.3 %, respectively, with respect to M. ruestringensis DSM 13258(T). The predominant isoprenoid quinone found in the four isolates and M. ruestringensis DSM 13258(T) was MK-6. The four strains contained iso-C(17 : 0) 3-OH, iso-C(15 : 1) and iso-C(15 : 0) as the major fatty acids. Their DNA G + C contents were 44.1-45.4 mol%. The levels of DNA-DNA relatedness indicated that strains SW-62(T) and SW-74 and strains SW-63(T) and SW-72 were members of two species that were different from M. ruestringensis. On the basis of phenotypic and phylogenetic data and genomic distinctiveness, strains SW-62(T) and SW-74 and strains SW-63(T) and SW-72 were placed in the genus Muricauda as two distinct novel species, for which the names Muricauda flavescens sp. nov. (type strain, SW-62(T) = KCCM 41645(T) = JCM 11812(T)) and Muricauda aquimarina sp. nov. (type strain, SW-63(T) = KCCM 41646(T) = JCM 11811(T)), respectively, are proposed.

Reclassification of [Cytophaga] marinoflava Reichenbach 1989 as Leeuwenhoekiella marinoflava gen. nov., comb. nov. and description of Leeuwenhoekiella aequorea sp. nov.

Five heterotrophic, aerobic, halotolerant and pigmented bacterial strains with gliding motility were isolated from Antarctic sea water; one other isolate was collected from the sea urchin Strongylocentrotus intermedius in the Gulf of Peter the Great in the Sea of Japan. 16S rRNA gene sequence analysis indicated that the strains are members of the family Flavobacteriaceae, the nearest neighbour (with 97.1 % sequence similarity) being the misclassified species [Cytophaga] marinoflava. DNA-DNA hybridization experiments and chemotaxonomic and phenotypic analyses demonstrated that the six novel isolates represent a single species distinct from [C.] marinoflava. On the basis of its separate phylogenetic lineage (the nearest neighbours show 92 % sequence similarity), [C.] marinoflava is reclassified as Leeuwenhoekiella marinoflava gen. nov., comb. nov. A second species of this new genus, Leeuwenhoekiella aequorea sp. nov., is proposed for the six novel isolates, with strain LMG 22550(T) (=CCUG 50091(T)) as the type strain.

Transfer of Chryseobacterium meningosepticum and Chryseobacterium miricola to Elizabethkingia gen. nov. as Elizabethkingia meningoseptica comb. nov. and Elizabethkingia miricola comb. nov.

The taxonomic positions of six strains (including the type strain) of Chryseobacterium meningosepticum (King 1959) Vandamme et al. 1994 and the type strain of Chryseobacterium miricola Li et al. 2004 were re-evaluated by using a polyphasic taxonomic approach. Phylogenetic analysis, based on 16S rRNA gene sequencing, showed that the strains represent a separate lineage from the type strains of the Chryseobacterium-Bergeyella-Riemerella branch within the family Flavobacteriaceae (90.7-93.9 % similarities), which was supported by phenotypic differences. Combined phylogenetic and phenotypic data showed that C. meningosepticum and C. miricola should be transferred to a new genus, Elizabethkingia gen. nov., with the names Elizabethkingia meningoseptica comb. nov. (type strain, ATCC 13253(T) = NCTC 10016(T) = LMG 12279(T) = CCUG 214(T)) and Elizabethkingia miricola comb. nov. (type strain, DSM 14571(T) = JCM 11413(T) = GTC 862(T)) proposed.

Kaistella koreensis gen. nov., sp. nov., a novel member of the Chryseobacterium-Bergeyella-Riemerella branch.

Gram-negative, non-spore-forming, rod-shaped, yellow-pigmented bacteria isolated from a freshwater stream in Korea were investigated to determine their taxonomic position. Complete 16S rRNA gene sequence analysis indicated that the organisms should be placed in the Chryseobacterium-Bergeyella-Riemerella branch in the family Flavobacteriaceae. Phylogenetically, the strains were most closely related to Chryseobacterium balustinum ATCC 33487(T) and Chryseobacterium scophthalmum LMG 13028(T) (94.3 and 94.1 % 16S rRNA gene sequence similarity, respectively) and they clustered on a separate well-supported branch. The strains contained menaquinone MK-6 as the predominant respiratory quinone and showed higher G+C contents (41.7 mol%) than other species in the Chryseobacterium-Bergeyella-Riemerella branch and i-C(15 : 0) as a major fatty acid (47-52 %). The phylogenetic distances from any species with validly published names and their phenotypic properties confirmed that the strains constitute a separate species in a new genus, for which the name Kaistella koreensis gen. nov., sp. nov. is proposed (type strain Chj707(T)=KCTC 12107(T)=IAM 15050(T)).

Maribacter gen. nov., a new member of the family Flavobacteriaceae, isolated from marine habitats, containing the species Maribacter sedimenticola sp. nov., Maribacter aquivivus sp. nov., Maribacter orientalis sp. nov. and Maribacter ulvicola sp. nov.

Six novel gliding, heterotrophic, Gram-negative, yellow-pigmented, aerobic, oxidase- and catalase-positive bacteria were isolated from the green alga Ulva fenestrata, sea water and a bottom sediment sample collected in the Gulf of Peter the Great, Sea of Japan. 16S rRNA gene sequence analysis revealed that the strains studied were members of the family Flavobacteriaceae. On the basis of their phenotypic, chemotaxonomic, genotypic and phylogenetic characteristics, the novel bacteria have been assigned to the new genus Maribacter gen. nov., as Maribacter sedimenticola sp. nov., Maribacter orientalis sp. nov., Maribacter aquivivus sp. nov. and Maribacter ulvicola sp. nov., with the type strains KMM 3903T (=KCTC 12966T=CCUG 47098T), KMM 3947T (=KCTC 12967T=CCUG 48008T), KMM 3949T (=KCTC 12968T=CCUG 48009T) and KMM 3951T (=KCTC 12969T=DSM 15366T), respectively.