Algibacter mikhailovii sp. nov., a novel marine bacterium of the family Flavobacteriaceae, and emended description of the genus Algibacter

Algibacter onchidii sp. nov., a symbiotic bacterium isolated from a marine invertebrate

A novel symbiotic bacterium, designated strain XY-114^T, was isolated from the cerata of an Onchidium marine invertebrate species collected in the South China Sea. Strain XY-114^T was an aerobic, Gram-stain-negative, non-motile and short rod-shaped bacterium (0.5-0.8 µm wide and 1.0-1.5 µm long) without flagellum. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain XY-114^T belonged to the genus Algibacter with the highest similarity of 97.2 % to the closest phylogenetic relative Algibacter aestuarii KYW371^T. Cells grew at 15-37 °C (optimum, 30 °C), at pH 5.5-9.0 (optimum 7.0-8.0) and at NaCl concentrations of 0.5-5.0 % (w/v; optimum 1.5-3.0 %). The major fatty acids (>10 %) were summed feature 3 (comprising C_16 : 1  ω7c and/or C_16 : 1  ω6c), iso-C_15 : 0, iso-C_15 : 1 G and iso-C_17 : 0 3-OH. The predominant polar lipid was phosphatidylethanolamine. The predominant respiratory quinone was MK-6. Flexirubin-type pigments were absent. The genome size of strain XY-114^T was 3.4 Mbp, with 34.9 mol% of DNA G+C content. The average nucleotide identity, digital DNA-DNA hybridization and amino acid identity values between strain XY-114^T and A. aestuarii KYW371^T were 74.5 %, 17.0±1.8 % and 73.9 %. Characterization based on phylogenetic, phenotypic, chemotaxonomic and genomic evidence demonstrated that strain XY-114^T represents a novel species of the genus Algibacter, for which the name Algibacter onchidii sp. nov. is proposed. The type strain is XY-114^T (=KCTC 72217^T=MCCC 1K03606^T).

Reclassification of Algibacter wandonensis as a Later Heterotypic Synonym of Algibacter lectus Based on Whole-Genome Sequence Analysis

The genus Algibacter belongs to the family Flavobacteriaceae of the Bacteroidetes, and all members of this genus were isolated from marine environments. Among the Algibacter species, two members, Algibacter lectus KMM 3902^T and Algibacter wandonensis WS-MY22^T, were isolated from green algae and sediment around a brown algae respectively. The 16S rRNA gene sequences of these two type strains possess 99.4% sequence similarity. In this study, further studies were undertaken to clarify the taxonomic assignments of the two species. Whole-genome sequence analysis showed that the similarities for other phylogenetic markers are also very high (i.e. 99.9% for gyrB, 99.6% for recA and 99.9% for rpoD). Average nucleotide identity, average amino acids identity and digital DNA-DNA hybridization value between A. lectus KMM 3902^T and A. wandonensis WS-MY22^T are 98.3%, 98.6% and 89.4% respectively, all clearly exceed suggested species delineation thresholds. Furthermore, phylogenetic trees based on sequences of 16S rRNA gene and up-to-date bacterial core gene set (UBCG) consisting of 92 genes provided additional evidence that A. lectus KMM 3902^T and A. wandonensis WS-MY22^T are very closely related. In addition, a review of their profiles indicated that A. lectus KMM 3902^T and A. wandonensis WS-MY22^T did not present pronounced differences at phenotypic and chemotaxonomic levels. Based on these evidence, we propose that A. wandonensis should be reclassified as later heterotypic synonyms of A. lectus.

Algibacter marinivivus sp. nov., isolated from the surface of a marine red alga

A Gram-stain-negative, non-flagellated bacterium, designated ZY111T, was isolated from the surface of a marine red alga, which was collected from the coast in Weihai, Shandong Province, PR China. Strain ZY111T exhibited growth at 4–37 °C (optimum, 25–28 °C) in the presence of 0–8.0 % (w/v) NaCl (optimum, 2.0–4.0% NaCl) and at pH 6.5–9.5 (optimum, pH 7.0–8.0). The 16S rRNA gene sequence analysis revealed that strain ZY111T belonged to the genus Algibacter , with Algibacter amylolyticus DSM 29199T as its closest relative (97.7 % similarity). The averagenucleotide identity value of strain ZY111T with A. amylolyticus DSM 29199T was 79.03 %. The digitalDNA–DNA hybridization value of strain ZY111T with A. amylolyticus DSM 29199T was 22.40 %. The dominant fatty acids were iso-C15 : 0, iso-C15 : 1 G, iso-C15 : 0 3-OH and iso-C17 : 0 3-OH. The sole respiratory quinone was determined to be menaquinone-6. The polar lipid profile of strain ZY111T consisted of phosphatidylethanolamine, two unidentified aminolipids and three unidentified lipids. The G+C content was 31.9 mol%. The phenotypic, chemotaxonomic and phylogenetic data clearly showed that strain ZY111T represents a novel species of the genus Algibacter , for which the name Algibacter marinivivus sp. nov. is proposed. The type strain is ZY111T (=KCTC 62373T=MCCC 1H00295T).

Pontimicrobium aquaticum gen. nov., sp. nov., a bacterium in the family Flavobacteriaceae isolated from seawater

A Gram-stain-negative, yellow-pigmented, non-spore-forming, non-motile, rod-shaped, catalase-positive, strictly aerobic bacterial strain, designated CAU 1491^T, was isolated from seawater and its taxonomic position was examined using a polyphasic approach. Cells of strain CAU 1491^T grew optimally at 30 °C, pH 7.5 and in 2.0 % (w/v) NaCl. Phylogenetic analysis based on the 16S rRNA gene sequence of CAU 1491^T showed that it formed a distinct lineage within the family Flavobacteriaceae as a separate deep branch, with 97.0 % or lower sequence similarity to representatives of the genera Lacinutrix, Gaetbulibacter and Aquibacter. The major cellular fatty acids of strain CAU 1491^T were iso-C_15 : 0, iso-C_15 : 1 G, iso-C_17 : 0 3-OH and summed feature 3. The polar lipid pattern consisted of diphosphatidylglycerol, phosphatidylserine, phosphatidylethanolamine and an unidentified phospholipid. The strain contained MK-6 as the sole respiratory quinone. Genome sequencing revealed that strain CAU 1491^T has a genome size of 3.13 Mbp and a G+C content of 32.4 mol%. On the basis of the phenotypic, chemotaxonomic and genomic data, strain CAU 1491^T represents a new genus and species in the family Flavobacteriaceae for which the name Pontimicrobium aquaticum gen. nov., sp. nov. is proposed. The type strain of Pontimicrobium aquaticum is CAU 1491^T (=KCTC 72003^T=NBRC 113695^T).

Algibacter pacificus sp. nov., isolated from a deep-sea seamount

The Gram-stain-negative, rod-shaped, yellow-pigmented and facultative anaerobic bacterial strain, designated H164T, was isolated from seawater collected from the Caroline Seamounts in the Pacific Ocean. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain H164T was related to the genus Algibacter and had highest 16S rRNA gene sequence similarity to Algibacter wandonensis WS-MY22T (97.4 %). The major cellular fatty acids were iso-C15 : 0, anteiso-C15 : 0, iso-C15 : 1 G, iso-C15 : 0 3-OH and iso-C17 : 0 3-OH. The predominant menaquinone was MK-6. The polar lipid profile contained phosphatidylethanolamine, one unidentified aminolipid and two unidentified lipids. The genomic DNA G+C content of strain H164T was 33.2 mol%. The values of in silico DNA–DNA hybridization (isDDH) and average nucleotide identity (ANI) between strain H164T and A. wandonensis KCTC 32381T were 26.10 and 81.88 %. The isDDH and ANI values between strain H164T and Algibacter lectus DSM 15365T were 25.40 and 81.79 %. Combined data from phenotypic, phylogenetic, isDDH and ANI analyses demonstrated that strain H164T represents a novel species of the genus Algibacter , for which we propose the name Algibacter pacificus sp. nov. (type strain H164T=KCTC 72432T=CGMCC 1.17117T).

Hansen K, Isaksson J, Ullsten S, H. Hansen E, Hammer Andersen J. Anti-Bacterial Effect and Cytotoxicity Assessment of Lipid 430 Isolated from Algibacter sp

Two bacterial isolates from the Barents Sea, both belonging to the genus Algibacter, were found to yield extracts with anti-bacterial bioactivity. Mass spectrometry guided dereplication and purification of the active extracts lead to the isolation of the same active principle in both extracts. The structure of the bioactive compound was identified via mass spectrometry and nuclear resonance spectroscopy and it turned out to be the known lipopeptide Lipid 430. We discovered and determined its previously unknown anti-bacterial activity against Streptococcus agalactiae and revealed a cytotoxic effect against the A2058 human melanoma cell line at significantly lower concentrations compared to its anti-bacterial concentration. Flow cytometry and microscopy investigations of the cytotoxicity against the melanoma cell line indicated that Lipid 430 did not cause immediate cell lysis. The experiments with melanoma cells suggest that the compound functions trough more complex pathways than acting as a simple detergent.

Analysis of 1,000 Type-Strain Genomes Improves Taxonomic Classification of Bacteroidetes

Although considerable progress has been made in recent years regarding the classification of bacteria assigned to the phylum Bacteroidetes, there remains a need to further clarify taxonomic relationships within a diverse assemblage that includes organisms of clinical, piscicultural, and ecological importance. Bacteroidetes classification has proved to be difficult, not least when taxonomic decisions rested heavily on interpretation of poorly resolved 16S rRNA gene trees and a limited number of phenotypic features. Here, draft genome sequences of a greatly enlarged collection of genomes of more than 1,000 Bacteroidetes and outgroup type strains were used to infer phylogenetic trees from genome-scale data using the principles drawn from phylogenetic systematics. The majority of taxa were found to be monophyletic but several orders, families and genera, including taxa proposed long ago such as Bacteroides, Cytophaga, and Flavobacterium but also quite recent taxa, as well as a few species were shown to be in need of revision. According proposals are made for the recognition of new orders, families and genera, as well as the transfer of a variety of species to other genera. In addition, emended descriptions are given for many species mainly involving information on DNA G+C content and (approximate) genome size, both of which can be considered valuable taxonomic markers. We detected many incongruities when comparing the results of the present study with existing classifications, which appear to be caused by insufficiently resolved 16S rRNA gene trees or incomplete taxon sampling. The few significant incongruities found between 16S rRNA gene and whole genome trees underline the pitfalls inherent in phylogenies based upon single gene sequences and the impediment in using ordinary bootstrapping in phylogenomic studies, particularly when combined with too narrow gene selections. While a significant degree of phylogenetic conservation was detected in all phenotypic characters investigated, the overall fit to the tree varied considerably, which is one of the probable causes of misclassifications in the past, much like the use of plesiomorphic character states as diagnostic features.

Thalassorhabdus aurantiaca gen. nov., sp. nov., a new member of the family Flavobacteriaceae isolated from seawater in South Korea

A novel Gram-negative, orange pigmented, strictly aerobic bacterium, designated strain IP9^T, was isolated from seawater at the sea shore of Incheon Eulwang-ri beach, South Korea. Cells of strain IP9^T were observed to be straight or slightly curved rods and colonies to be round and convex. Strain IP9^T was found to be catalase and oxidase positive, and non-motile. Growth was observed in the temperature range of 10-37 °C (optimum at 30 °C), pH range of 6-10 (optimum at pH 7-8) and salt concentration range of 0-7% (w/v) NaCl (optimum at 0-1%). On the basis of 16S rRNA gene sequence similarity and phylogenetic analysis, strain IP9^T was found to be related to the members of the family Flavobacteriaceae, being closely related to Hwangdonia seohaensis KCTC 32177^T (95.3% sequence similarity). The DNA G + C content of the novel strain was determined to be 39.1 mol%. The major polar lipids were found to be phosphatidylethanolamine, three unidentified aminoglycolipids and two unidentified glycolipids. The major fatty acids (> 10%) were identified as iso-C_15:0 and iso-C_17:0 3-OH. The predominant quinone was found to be menaquinone 6 (MK-6). Based on the biochemical, phylogenetic and physiological data, we conclude that strain IP9^T (= KCTC 52523^T = JCM 31732^T) represents the type species of a novel genus of the family Flavobacteriaceae for which the name Thalassorhabdus aurantiaca gen. nov., sp. nov. is proposed.

Isolation and Complete Genome Sequence of Algibacter alginolytica sp. nov., a Novel Seaweed-Degrading Bacteroidetes Bacterium with Diverse Putative Polysaccharide Utilization Loci

The members of the phylum Bacteroidetes are recognized as some of the most important specialists for the degradation of polysaccharides. However, in contrast to research on Bacteroidetes in the human gut, research on polysaccharide degradation by marine Bacteroidetes is still rare. The genus Algibacter belongs to the Flavobacteriaceae family of the Bacteroidetes, and most species in this genus are isolated from or near the habitat of algae, indicating a preference for the complex polysaccharides of algae. In this work, a novel brown-seaweed-degrading strain designated HZ22 was isolated from the surface of a brown seaweed (Laminaria japonica). On the basis of its physiological, chemotaxonomic, and genotypic characteristics, it is proposed that strain HZ22 represents a novel species in the genus Algibacter with the proposed name Algibacter alginolytica sp. nov. The genome of strain HZ22, the type strain of this species, harbors 3,371 coding sequences (CDSs) and 255 carbohydrate-active enzymes (CAZymes), including 104 glycoside hydrolases (GHs) and 18 polysaccharide lyases (PLs); this appears to be the highest proportion of CAZymes (∼7.5%) among the reported strains in the class Flavobacteria Seventeen polysaccharide utilization loci (PUL) are predicted to be specific for marine polysaccharides, especially algal polysaccharides from red, green, and brown seaweeds. In particular, PUL N is predicted to be specific for alginate. Taking these findings together with the results of assays of crude alginate lyases, we prove that strain HZ22(T) can completely degrade alginate. This work reveals that strain HZ22(T) has good potential for the degradation of algal polysaccharides and that the structure and related mechanism of PUL in strain HZ22(T) are worth further research.

Isolation and characterization of a novel marine Bacteroidetes as Algitalea ulvae gen. nov., sp. nov., isolated from the green alga Ulva pertusa

A polyphasic taxonomic investigation was performed on a bacterial strain, 38-Ka-2(T), which was isolated from the green alga Ulva pertusa Kjellman (Chlorophyta) in Hokkaido, Japan. The bacterial cells were observed to be golden-yellow coloured, Gram-negative, strictly aerobic, non-spore-forming, non-motile and rod-shaped. Phylogenetic analyses based on the 16S rRNA gene sequence indicated that the new strain is a member of the family Flavobacteriaceae within the phylum Bacteroidetes and that it shows high sequence similarity (94.8 %) to Aquimarina addita JC2680(T). The genomic DNA G+C content of strain 38-Ka-2(T) was determined to be 36 mol%; MK-6 was identified as the major menaquinone; and the presence of iso-C15:0, C18:0 and iso-C17:0 3-OH as the major (>10 %) cellular fatty acids. The polar lipid profile was found to consist of phosphatidylethanolamine, an unidentified glycolipid and two unidentified lipids. From the distinct phylogenetic position and combination of genotypic and phenotypic characteristics, strain 38-Ka-2(T) is considered to represent a novel genus for which the name Algitalea ulvae gen. nov., sp. nov. is proposed. The type strain of A. ulvae is 38-Ka-2(T) (=KCTC 32994(T) = NBRC 110017(T)).

Algibacter amylolyticus sp. nov., isolated from intertidal sediment

A Gram-reaction-negative, rod-shaped, yellow-pigmented, motile by gliding bacterial strain, designated RU-4-M-4T, was isolated from intertidal sediment of Sakhalin Island in Russia. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain RU-4-M-4T was related to the genus Algibacter and had highest 16S rRNA gene sequence similarity with Algibacter pectinivorans KACC 14153T (97.2 %). The major cellular fatty acids were iso-C15 : 0 3-OH, C15 : 0 and iso-C15 : 1 G. The predominant menaquinone was MK-6. The polar lipid profile contained phosphatidylethanolamine, three unidentified aminolipids and two unidentified lipids. The genomic DNA G+C content of strain RU-4-M-4T was 36.4 mol%. Combined data from phenotypic, phylogenetic and DNA–DNA relatedness studies demonstrated that strain RU-4-M-4T is a representative of a novel species of the genus Algibacter , for which we propose the name Algibacter amylolyticus sp. nov. (type strain RU-4-M-4T = LMG 28383T = DSM 29199T).

Algibacter psychrophilus sp. nov., a psychrophilic bacterium isolated from marine sediment

A Gram-stain-negative, aerobic, yellow-pigmented, flexirubin-negative, rod-shaped, non-motile and psychrophilic bacterial strain, PAMC 27237T, was isolated from marine sediment of the Ross Sea, Antarctica. Strain PAMC 27237T grew at 0-20 °C (optimally at 17 °C), at pH 5.0-9.5 (optimally at pH 7.0) and in the presence of 0-3.5 % (w/v) NaCl (optimally at 1.5-2.5 %). The major fatty acids (≥5 %) were iso-C17 : 0 3-OH, C17 : 0 2-OH, anteiso-C15 : 0, summed feature 3 (C16 : 1ω6c/C16 : 1ω7c), iso-C15 : 0 3-OH, anteiso-C17 : 1ω9c, anteiso-C15 : 1 A, iso-C16 : 0 3-OH and iso-C15 : 1 G. The major polar lipids were phosphatidylethanolamine, two unidentified aminolipids, four unidentified lipids and a glycolipid. The major respiratory quinone was MK-6. Phylogenetic analysis based on the 16S rRNA gene sequence revealed that strain PAMC 27237T belongs to the genus Algibacter, showing high similarities with the type strains of Algibacter agarivorans (97.2 %), Algibacter agarilyticus (97.0 %) and Algibacter mikhailovii (96.4 %). Average nucleotide identity values between strain PAMC 27237T and the type strains of A. agarivorans and A. agarilyticuswere 83.1 and 84.2 %, respectively, and mean genome-to-genome distances were 22.4-24.2 %, indicating that strain PAMC 27237T is clearly distinguished from the most closely related species of the genus Algibacter. The genomic DNA G+C content calculated from genome sequences was 33.5 mol%. Based on the phenotypic, chemotaxonomic and phylogenetic data presented, strain PAMC 27237T is considered to represent a novel species of the genus Algibacter, for which the name Algibacter psychrophilus sp. nov. is proposed. The type strain is PAMC 27237T ( = KCTC 42130T = JCM 30370T).

Algibacter wandonensis sp. nov., isolated from sediment around a brown algae (Undaria pinnatifida) reservoir

A Gram-stain-negative, non-flagellated, rod-shaped bacterial strain able to move by gliding, designated WS-MY22(T), was isolated from sediment around a brown algae reservoir located on Wando in South Korea. It grew 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 showed that strain WS-MY22(T) clustered coherently with the type strains of Algibacter lectus and Algibacter undariae. It exhibited sequence similarity of 99.4 and 98.9 % to the type strains of A. lectus and A. undariae, respectively, and of 95.1-96.6 % to those of the other species of the genus Algibacter. Strain WS-MY22(T) contained MK-6 as the predominant menaquinone and iso-C15 : 1 G and iso-C17 : 0 3-OH as the major fatty acids. The major polar lipids of strain WS-MY22(T) were phosphatidylethanolamine and two unidentified lipids. The DNA G+C content of strain WS-MY22(T) was 35.8 mol% and its DNA-DNA relatedness with A. lectus KCTC 12103(T) and A. undariae WS-MY9(T) was 31 and 19 %, respectively. The phylogenetic and genetic distinctiveness and differential phenotypic properties revealed that strain WS-MY22(T) is separate from other species of the genus Algibacter. On the basis of the data presented, strain WS-MY22(T) is considered to represent a novel species of the genus Algibacter, for which the name Algibacter wandonensis sp. nov. is proposed. The type strain is WS-MY22(T) ( = KCTC 32381(T) = CECT 8301(T)).

Algibacter undariae sp. nov., isolated from a brown algae reservoir

A Gram-stain-negative, non-flagellated, rod-shaped bacterial strain able to move by gliding, designated WS-MY9(T), was isolated from a brown algae reservoir in South Korea. Strain WS-MY9(T) grew optimally at 25 °C, at pH 7.0-8.0 and in the presence of 2 % (w/v) NaCl. A neighbour-joining phylogenetic tree based on 16S rRNA gene sequences showed that strain WS-MY9(T) clustered with the type strain of Algibacter lectus with a bootstrap resampling value of 100 %. Strain WS-MY9(T) exhibited 16S rRNA gene sequence similarity values of 98.5 and 96.7 % to the type strains of A. lectus and Algibacter mikhailovii, respectively, and less than 96.1 % sequence similarity to other members of the family Flavobacteriaceae. Strain WS-MY9(T) contained MK-6 as the predominant menaquinone and anteiso-C15 : 0, iso-C17 : 0 3-OH, iso-C15 : 1 G and iso-C15 : 0 as the major fatty acids. The major polar lipids of strain WS-MY9(T) were phosphatidylethanolamine and two unidentified lipids. The DNA G+C content of strain WS-MY9(T) was 35.0 mol% and its DNA-DNA relatedness value with A. lectus KCTC 12103(T) was 15 %. The phylogenetic and genetic distinctiveness and differential phenotypic properties revealed that strain WS-MY9(T) is separate from the two recognized species of the genus Algibacter. On the basis of the data presented, strain WS-MY9(T) represents a novel species of the genus Algibacter, for which the name Algibacter undariae sp. nov. is proposed. The type strain is WS-MY9(T) ( = KCTC 32259(T) = CCUG 63684(T)).

Algibacter agarivorans sp. nov. and Algibacter agarilyticus sp. nov., isolated from seawater, reclassification of Marinivirga aestuarii as Algibacter aestuarii comb. nov. and emended description of the genus Algibacter

Two yellow-pigmented, rod-shaped, non-motile, Gram-reaction-negative and aerobic bacterial strains, designated KYW560T and KYW563T, were isolated from seawater collected from Gwangyang Bay, Republic of Korea. The isolates required sea salts for growth. Flexirubin-type pigments were absent. The common major cellular fatty acids (>5 % of total) of the two strains were C16 : 0, C18 : 0, iso-C15 : 0, anteiso-C15 : 0, iso-C15 : 1 G, iso-C17 : 0 3-OH and summed feature 3 (C16 : 1ω6c and/or C16 : 1ω7c). Strain KYW560T also contained iso-C15 : 0 3-OH and C20 : 1ω9c as major fatty acids. The main polar lipids were phosphatidylethanolamine, an unidentified aminolipid and two unidentified lipids. The predominant isoprenoid quinone was MK-6. The DNA G+C contents of strains KYW560T and KYW563T were 41.0±0.7 and 38.3±0.4 mol% (mean±sd of three determinations), respectively. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the isolates belonged to the family Flavobacteriaceae , and were related to the genus Algibacter . Based on data from this taxonomic study using a polyphasic approach, it is proposed that the isolates represent novel species of the genus Algibacter , for which the names Algibacter agarivorans sp. nov. (type strain, KYW560T = KCTC 23855T = JCM 18285T) and Algibacter agarilyticus sp. nov. (type strain, KYW563T = KCTC 23857T = JCM 18275T) are proposed. Reclassification of Marinivirga aestuarii as Algibacter aestuarii comb. nov. and emended description of the genus Algibacter are also proposed.

Algibacter miyuki sp. nov., a member of the family Flavobacteriaceae isolated from leachate of a brown algae reservoir

A Gram-negative, aerobic, non-flagellated, non-gliding and rod-shaped bacterial strain, designated WS-MY6(T), was isolated from a brown algae reservoir in South Korea. Strain WS-MY6(T) grew optimally at 25 °C, at pH 7.0-8.0 and in the presence of 2 % (w/v) NaCl. Neighbour-joining, maximum-likelihood and maximum-parsimony phylogenetic trees based on 16S rRNA gene sequences showed that strain WS-MY6(T) clustered with the type strains of Algibacter lectus and 'Algibacter undariae', showing 16S rRNA gene sequence similarity values of 98.1 and 98.4 %, respectively. It exhibited sequence similarities of 95.4-96.7 % to the type strains of the other Algibacter species, Pontirhabdus pectinovorans and Marinivirga aestuarii, whose reclassification into the genus Algibacter has been recently proposed. Strain WS-MY6(T) contained MK-6 as the predominant menaquinone and iso-C15:1 G, anteiso-C15:0 and iso-C17:0 3-OH as the major fatty acids. It contained phosphatidylethanolamine and two unidentified lipids as the major polar lipids. The DNA G + C content of strain WS-MY6(T) was 35.3 mol% and its DNA-DNA relatedness values with A. lectus KCTC 12103(T) and 'A. undariae' WS-MY9(T) was 21 and 13 %, respectively. The phylogenetic and genetic distinctiveness and differential phenotypic properties revealed that strain WS-MY6(T) is separate from existing Algibacter species. On the basis of the data presented, strain WS-MY6(T) is considered to represent a novel species of the genus Algibacter, for which the name Algibacter miyuki sp. nov. is proposed. The type strain is WS-MY6(T) (=KCTC 32382(T) =CECT 8300(T)).

Arenitalea lutea gen. nov., sp. nov., a marine bacterium of the family Flavobacteriaceae isolated from intertidal sand

A yellow, rod-shaped, Gram-negative, facultatively aerobic, gliding bacterium, designed strain P7-3-5T, was isolated from intertidal sand of the Yellow Sea, China. Analysis of 16S rRNA gene sequences revealed that strain P7-3-5T formed a distinct lineage within the family Flavobacteriaceae , sharing 94.2–96.9 % sequence similarity with type strains of species of the most closely related genera, including Hyunsoonleella , Jejuia , Marinivirga and Algibacter . The strain grew at 4–40 °C and with 0.5–5.0 % (w/v) NaCl. It reduced nitrate to nitrite and hydrolysed gelatin and DNA. The major cellular fatty acids were iso-C15 : 0, iso-C15 : 1 G and anteiso-C15 : 0 and the major respiratory quinone was MK-6. Polar lipids included phosphatidylethanolamine (PE), three unidentified aminolipids (AL1–3) and four unidentified lipids (L1–4). The genomic DNA G+C content of strain P7-3-5T was 32.1 mol%. Data from this polyphasic study suggest that strain P7-3-5T represents a novel species in a new genus in the family Flavobacteriaceae , for which the name Arenitalea lutea gen. nov., sp. nov. is proposed. The type strain of Arenitalea lutea is P7-3-5T ( = CGMCC 1.12213T = KACC 16457T).

Marinivirga aestuarii gen. nov., sp. nov., a member of the family Flavobacteriaceae , isolated from marine environments, and emended descriptions of the genera Hyunsoonleella , Jejuia and Pontirhabdus and the species Hyunsoonleella jejuensis , Jejuia pallidilutea and Pontirhabdus pectinivorans

Two orange, rod-shaped, Gram-reaction-negative, aerobic bacterial strains devoid of flagella and gliding motility, designated strains KYW371T and KS18 were isolated from a seawater sample and a shellfish Ruditapes philippinarum, respectively, collected from Gwangyang Bay, Republic of Korea. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the two strains belonged to the family Flavobacteriaceae ; and that strain KYW371T was most closely related to Algibacter mikhailovii LMG 23988T (96.7 % sequence similarity), Pontirhabdus pectinivorans JC2675T (96.3 %), Postechiella marina M091T (95.6 %) and Hyunsoonleella jejuensis CNU004T (95.3 %). The 16S rRNA gene sequence similarity (98.8 %) and DNA–DNA relatedness (78.1 %) between strains KYW371T and KS18 indicated that these two strains represented a single species. The predominant cellular fatty acids of strain KYW371T were iso-C15 : 1 G, iso-C15 : 0, iso-C15 : 0 3-OH and iso-C17 : 0 3-OH. Flexirubin-type pigments were absent. MK-6 was the only isoprenoid quinone and the DNA G+C content was 34.8–36.6 mol%. Data from this taxonomic study employing a polyphasic approach suggested that the isolates represent a novel species in a new genus in the family Flavobacteriaceae , for which the name Marinivirga aestuarii gen. nov., sp. nov. is proposed. The type strain is KYW371T ( = KCTC 23449T = JCM 17452T), and an additional strain of the species is KS18 ( = KCTC 23128 = JCM 16845). Emended descriptions of the genera Hyunsoonleella , Jejuia and Pontirhabdus and the species Hyunsoonleella jejuensis , Jejuia pallidilutea and Pontirhabdus pectinivorans are also proposed.

Algibacter aquimarinus sp. nov., isolated from a marine environment, and reclassification of Pontirhabdus pectinivorans as Algibacter pectinivorans comb. nov

An orange-coloured, rod-shaped, Gram-reaction-negative and aerobic bacterial strain, designated KYW589(T), was isolated from seawater collected from Gwangyang Bay, Republic of Korea. The isolate required sea salts for growth. Gliding motility was observed. Flexirubin-type pigments were absent. Major cellular fatty acids (>10% of the total) were iso-C15:0, iso-C17:0 3-OH, iso-C15:1 G, C16:0, iso-C15:0 3-OH and C18:0. The main polar lipids were phosphatidylethanolamine, two unidentified aminolipids and two unidentified lipids. The predominant isoprenoid quinone was MK-6. The DNA G+C content was 38.6 ± 0.7 mol% (mean ± sd of three determinations). Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain KYW589(T) belongs to the family Flavobacteriaceae, and was related to the genus Algibacter. Based on data from a study using a polyphasic taxonomic approach, it is proposed that strain KYW589(T) represents a novel species belonging to the genus Algibacter, for which the name Algibacter aquimarinus sp. nov. is proposed. The type strain is KYW589(T) (=KCTC 23928(T) =JCM 18287(T)). Reclassification of Pontirhabdus pectinivorans Yi et al. 2011 to the genus Algibacter, as Algibacter pectinivorans comb. nov. (type strain JC2675(T) =KACC 14153(T) =JCM 17107(T)), is also proposed.

Flavivirga jejuensis gen. nov., sp. nov., and Flavivirga amylovorans sp. nov., new members of the family Flavobacteriaceae isolated from seawater, and emended descriptions of the genera Psychroserpens and Lacinutrix

Two yellow, rod-shaped, Gram-reaction-negative, strictly aerobic bacterial strains, designated JC2682T and JC2681T, were isolated from a seawater sample of Jeju Island, Korea. The isolates required sea salts for growth and showed gliding motility. Phylogenetic analyses based on 16S rRNA gene sequences revealed that strains JC2682T and JC2681T shared 96.9 % similarity and formed a robust monophyletic group within the radiation encompassing the family Flavobacteriaceae . This distinct clade, which had varying branch positions depending on the tree-making algorithm used, represents a new genus within the family Flavobacteriaceae . The predominant isoprenoid quinone (menaquinone 6, MK-6) and DNA G+C content (27–33 mol%) were consistent with its assignment to the family Flavobacteriaceae , but the polar lipid profile, fatty acid composition and overall phenotypic traits demonstrated that the test strains were not closely affiliated to any recognized genera. Based on data from the present polyphasic taxonomic study, strains JC2682T and JC2681T are considered to represent two novel species of a new genus in the family Flavobacteriaceae , for which the names Flavivirga jejuensis gen. nov., sp. nov. and Flavivirga amylovorans sp. nov. are proposed, respectively. The type strain of Flavivirga jejuensis is JC2682T ( = KACC 14158T  = JCM 17113T). The type strain of Flavivirga amylovorans is JC2681T ( = KACC 14157T  = JCM 17112T). Amended descriptions of the genera Psychroserpens and Lacinutrix are provided.

Pontirhabdus pectinivorans gen. nov., sp. nov., isolated from seawater

A yellow-coloured, rod-shaped, Gram-reaction-negative and aerobic bacterial strain, designated JC2675T, was isolated from a seawater sample from Jeju Island, Korea. The isolate required sea salts for growth. Gliding motility was observed. Flexirubin-type pigments were absent. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain JC2675T represented a distinct phyletic line that reflected a novel generic status within the family Flavobacteraceae with relatively low gene sequence similarities (<95.7 %) to other recognized genera. The predominant isoprenoid quinone (MK-6) and DNA G+C content (30 mol%) were consistent with the assignment of the novel strain to the family Flavobacteriaceae, but overall phenotypic traits demonstrated that the novel strain was not closely affiliated with any previously described genus. Based on data from a study using a polyphasic taxonomic approach, it is proposed that strain JC2675T represents a new genus and novel species belonging to the family Flavobacteriaceae, for which the name Pontirhabdus pectinivorans gen. nov., sp. nov. is proposed. The type strain of the type species is JC2675T ( = KACC 14153T = JCM 17107T).

Postechiella marina gen. nov., sp. nov., isolated from seawater

A Gram-staining-negative, strictly aerobic, non-motile, yellow-pigmented bacterium, designated strain M091(T), was isolated from seawater at Damupo beach in Pohang, Republic of Korea, and investigated using a polyphasic taxonomic approach. The novel strain grew optimally at 25 °C, pH 7.0-8.0, and in the presence of 3% (w/v) NaCl. In a phylogenetic analysis based on 16S rRNA gene sequences, strain M091(T) formed a lineage within the family Flavobacteriaceae that was distinct from the most closely related genera of Flaviramulus (95.1% sequence similarity), Algibacter (94.9-93.9%), Mariniflexile (94.8-94.2%), Winogradskyella (94.8-93.2%), Lacinutrix (94.7-93.8%) and Tamlana (94.7-92.9%). The polar lipid profile of the novel strain comprised phosphatidylethanolamine, two unidentified aminolipids, one unidentified phospholipid and seven unidentified lipids. The predominant cellular fatty acids were iso-C(15:0) (20.5%), iso-C(17:0) 3-OH (15.4%), iso-C(15:0) 3-OH (12.4%), C(15:0) (10.9%) and iso-C(15:1) G (9.9%). The genomic DNA G+C content of strain M091(T) was 34.4 mol% and the major respiratory quinone was MK-6. Based on phenotypic and genotypic data, strain M091(T) represents a new genus and novel species in the family Flavobacteriaceae, for which the name Postechiella marina gen. nov., sp. nov. is proposed. The type strain of the type species is M091(T) (=KCTC 23537(T)=JCM 17630(T)).

Hyunsoonleella jejuensis gen. nov., sp. nov., a novel member of the family Flavobacteriaceae isolated from seawater

A novel marine, Gram-staining-negative, yellow-pigmented, rod-shaped bacterial strain, designated CNU004T, was isolated from a seawater sample collected on the coastline of Jeju Island, South Korea. The strain was strictly aerobic, non-flagellated, non-gliding and oxidase- and catalase-positive. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain CNU004T belongs to a distinct lineage in the family Flavobacteriaceae. Strain CNU004T exhibited levels of 16S rRNA gene sequence similarity of 93.8–93.9 % to its nearest phylogenetic neighbours, members of the genera Gaetbulibacter, Yeosuana and Algibacter. The new isolate required sea salts or artificial seawater for growth. The optimum ranges of temperature and pH for growth were 30–35 °C and pH 7.0–8.0. The DNA G+C content of strain CNU004T was 37.7 mol%. The major fatty acids were iso-C15 : 0, iso-C15 : 1 G, iso-C17 : 0 3-OH and iso-C15 : 0 3-OH. Menaquinone-6 was the major respiratory quinone. Zeaxanthin was the major carotenoid pigment produced, and flexirubin-type pigments were not produced. Strain CNU004T was able to degrade starch and agar. Based on its phenotypic and genotypic characteristics and on the phylogenetic evidence presented, strain CNU004T is considered to represent a novel species of a new genus in the family Flavobacteriaceae, for which the name Hyunsoonleella jejuensis gen. nov., sp. nov. is proposed. The type strain of Hyunsoonleella jejuensis sp. nov. is CNU004T (=KCTC 22242T =DSM 21035T).

Meridianimaribacter flavus gen. nov., sp. nov., a member of the family Flavobacteriaceae isolated from marine sediment of the South China Sea

A Gram-staining-negative, rod-shaped marine bacterium, designated strain NH57NT, isolated from sandy sediment in the Mischief Reef of the South China Sea, was characterized based on its physiological and biochemical features, fatty acid profile and phylogenetic position. 16S rRNA gene sequence analysis revealed a clear affiliation with the family Flavobacteriaceae. Strain NH57NT showed the closest phylogenetic relationship with members of the genera Gaetbulibacter, Gelidibacter, Subsaxibacter, Subsaximicrobium and Yeosuana; levels of 16S rRNA gene sequence similarity between strain NH57NT and the type strains of related species ranged from 94.9 to 91.2 %. Cells of strain NH57NT were motile by gliding and grew on solid media as yellow colonies at 9–37 °C, pH 6.5–8.5 and in the presence of 0.5–4.0 % NaCl. The DNA G+C content was 32.7 mol% and the predominant fatty acids were iso-C15 : 1 (22.7 % of the total), iso-C15 : 0 (20.7 %), iso-C17 : 0 3-OH (9.5 %), iso-C16 : 0 3-OH (8.3 %), C15 : 0 (7.8 %) and iso-C15 : 0 3-OH (5.8 %). Based on the physiological and phylogenetic data, and on the fatty acid composition, strain NH57NT is considered to represent a novel species of a new genus in the family Flavobacteriaceae, for which the name Meridianimaribacter flavus gen. nov., sp. nov. is proposed. The type strain of Meridianimaribacter flavus is NH57NT (=CCTCC AB 208318T=LMG 24839T=MCCC 1A03544T).