Thermococcus argininiproducens sp. nov., an arginine biosynthesis archaeal species isolated from the Central Indian Ocean ridge.

A strictly anaerobic hyperthermophilic archaeon, designated strain IOH2T, was isolated from a deep-sea hydrothermal vent (Onnuri vent field) area on the Central Indian Ocean Ridge. Strain IOH2T showed high 16S rRNA gene sequence similarity to Thermococcus sibiricus MM 739T (99.42 %), Thermococcus alcaliphilus DSM 10322T (99.28 %), Thermococcus aegaeus P5T (99.21 %), Thermococcus litoralis DSM 5473T (99.13 %), 'Thermococcus bergensis' T7324T (99.13 %), Thermococcus aggregans TYT (98.92 %) and Thermococcus prieurii Bio-pl-0405IT2T (98.01 %), with all other strains showing lower than 98 % similarity. The average nucleotide identity and in silico DNA-DNA hybridization values were highest between strain IOH2T and T. sibiricus MM 739T (79.33 and 15.00 %, respectively); these values are much lower than the species delineation cut-offs. Cells of strain IOH2T were coccoid, 1.0-1.2 µm in diameter and had no flagella. Growth ranges were 60-85 °C (optimum at 80 °C), pH 4.5-8.5 (optimum at pH 6.3) and 2.0-6.0 % (optimum at 4.0 %) NaCl. Growth of strain IOH2T was enhanced by starch, glucose, maltodextrin and pyruvate as a carbon source, and elemental sulphur as an electron acceptor. Through genome analysis of strain IOH2T, arginine biosynthesis related genes were predicted, and growth of strain IOH2T without arginine was confirmed. The genome of strain IOH2T was assembled as a circular chromosome of 1 946 249 bp and predicted 2096 genes. The DNA G+C content was 39.44 mol%. Based on the results of physiological and phylogenetic analyses, Thermococcus argininiproducens sp. nov. is proposed with type strain IOH2T (=MCCC 4K00089T=KCTC 25190T).

Proteiniclasticum aestuarii sp. nov., isolated from tidal flat sediment, and emended descriptions of the genus Proteiniclasticum and Proteiniclasticum ruminis.

A novel bacterium, designated SCR006T, was isolated from tidal flat sediment from Suncheon Bay, Republic of Korea. Cells of strain SCR006T were strictly anaerobic, motile cocci, Gram-reaction-negative, and catalase- and oxidase-negative. Growth was observed at 4-41 °C (optimum, 34-37 °C), at pH 6.5-10.0 (optimum, pH 7.0-7.5) and in presence of 0-8 % NaCl (optimum, 0-2 %). Fermentation products of peptone-yeast-glucose medium were acetate and ethanol. Results of phylogenetic analyses based on 16S rRNA gene sequences indicated that strain SCR006T had high sequence similarity to Proteiniclasticum ruminis D3RC-2T (97.9 %), followed by Youngiibacter multivorans DSM 6139T (95.9 %) and Youngiibacter fragilis 232.1T (95.0 %). The average nucleotide identity value between strain SCR006T and P. ruminis DSM 24773T was 72.7 %, which strongly supported that strain SCR006T reresents a novel species within the genus Proteiniclasticum. The major cellular fatty acids are iso-C15 : 0 (27.2 %) and anteiso-C15 : 0 (16.9 %). The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, two unidentified phospholipids, an unidentified aminolipid and five unidentified lipids. The genomic size was 3.2 Mb with genomic DNA G+C content of 45.6 mol%. The results of 16S rRNA-based and genome-based phylogenetic tree analyses indicated that SCR006T should be assigned to the genus Proteiniclasticum. Strain SCR006T could be distinguished from P. ruminis D3RC-2T by its growth conditions, cell morphology and genomic characteristics. Based on the phenotypic, phylogenetic, genomic and chemotaxonomic features, strain SCR006T represents a novel species, for which the name Proteiniclasticum aestuarii sp. nov. is proposed, with the type strain SCR006T (=KCTC 25245T= JCM 34531T).

Alkalibacter rhizosphaerae sp. nov., a CO-utilizing bacterium isolated from tidal flat sediment, and emended description of the genus Alkalibacter.

A novel anaerobic, rod-shaped, non-motile bacterium, designated strain ES005T, was isolated from tidal flat sediments near the rhizosphere of Phragmites australis at Eulsukdo Island, Republic of Korea. A polyphasic approach revealed that cells of the strain were Gram-stain-positive, catalase- and oxidase-negative, non-spore-forming rods. Phylogenetic analyses based on 16S rRNA gene sequences revealed that strain ES005T belonged to the family Eubacteriaceae, class Clostridia and showed the highest sequence similarity to Alkalibacter mobilis (97.52 %) and followed by Alkalibacter saccharofermentans Z-79820T (96.72%). The OrthoANI value between strain ES005T and A. mobilis was 69.67 %. Strain ES005T grew optimally at 33-37 °C, at pH 6.0-7.0 and in the presence of 1-2 % (w/v) NaCl. Growth in 12.5 % CO atmosphere was observed. Acetate and formate were end products of fructose fermentation and growth on CO. The major cellular fatty acids of strain ES005T were C14 : 0 (39.1 %) and C16 : 0 (26.6 %). The major polar lipids were diphoshatidylgycerol, phosphatidylglycerol and three unidentified phospholipids. The DNA G+C content of strain ES005T was 46.9 mol%. Based on the phenotypic, phylogenetic, genomic and chemotaxonomic features of the isloate, strain ES005T represents a novel species, for which the name Alkalibacter rhizosphaerae sp. nov. is proposed. The type strain is ES005T (=KCTC 25246T=JCM 34530T).

Probiotic effects of Pseudoalteromonas ruthenica: Antibacterial, immune stimulation and modulation of gut microbiota composition.

This study aimed to characterise and evaluate the probiotic properties of a newly isolated marine bacterium, strain S6031. The isolated strain was identified as Pseudoalteromonas ruthenica. In vivo experiments were conducted with P. ruthenica-immersed larvae and P. ruthenica-enriched Artemia fed to adult zebrafish. Disease tolerance of larval zebrafish against Edwardsiella piscicida was demonstrated by 66.34% cumulative per cent survival (CPS) in the P. ruthenica-exposed group, which was higher than the CPS of the control (46.67%) at 72 h post challenge (hpc). Heat-stressed larvae had 55% CPS in the P. ruthenica-immersed group, while the control had 30% CPS at 60 hpc. Immune-stress response gene transcripts (muc5.1, muc5.2, muc5.3, alpi2, alpi3, hsp70, and hsp90a) were induced, while pro-inflammatory genes (tnfα, il1b, and il6) were downregulated in P. ruthenica-immersed larvae compared to the control. This trend was confirmed by low pro-inflammatory and high stress-responsive protein expression levels in P. ruthenica-exposed larvae. Adult zebrafish had higher CPS (27.2%) in the P. ruthenica-fed group than the control (9.52%) upon E. piscicida challenge, suggesting increased disease tolerance. Histological analysis demonstrated modulation of goblet cell density and average villus height in the P. ruthenica-supplemented group. Metagenomics analysis clearly indicated modulation of alpha diversity indices and the relative abundance of Proteobacteria in the P. ruthenica-supplemented zebrafish gut. Furthermore, increased Firmicutes colonisation and reduced Bacteroidetes abundance in the gut were observed upon P. ruthenica supplementation. Additionally, this study confirmed the concentration-dependent increase of colony dispersion and macrophage uptake upon mucin treatment. In summary, P. ruthenica possesses remarkable functional properties as a probiotic that enhances host defence against diseases and thermal stress.

Oricola thermophila sp. nov., a marine bacterium isolated from tidal flat sediment and emended description of the genus Oricola Hameed et al. 2015.

A Gram-stain-negative, facultatively anaerobic, rod-shaped (1.8-4.4×0.5-0.7 µm) and motile marine bacterium, designated as MEBiC13590T, was isolated from tidal flat sediment sampled at Incheon City, on the west coast of the Republic of Korea. The 16S rRNA gene sequence analysis revealed that strain MEBiC13590T showed high similarity to Oricola cellulosilytica CC-AMH-0T (98.2 %), followed by Oceaniradius stylonematis StC1T (97.5 %); however, it clustered with Oricola cellulosilytica. The phylogenomic tree inferred by the up-to-date bacterial core gene set suggested that strain MEBiC13590T shared a phyletic line with Oricola cellulosilytica. Average nucleotide identity and digital DNA-DNA hybridization values (75.0 and 19.3 %, respectively) between strain MEBiC13590T and Oricola cellulosilytica CC-AMH-0T were below the respective species delineation cutoffs. Growth was observed at 22-50 °C (optimum, 45 °C), at pH 5-9 (optimum, pH 7) and with 1-6 % (optimum, 3 %) NaCl. The predominant cellular fatty acids were C16 : 0 (7.6 %), C18 : 0 (12.2 %), 11-methyl C18 : 1 ω7c (5.7 %), C19 : 0 cyclo ω6c and summed feature 8 (comprising C18 : 1 ω7c and/or C18 : 1 ω6c; 38 %). The DNA G+C content was 63.5 mol%. The major respiratory quinone was Q-10. Several phenotypic characteristics such as growth temperature, oxygen requirement, enzyme activities of urease, gelatinase, lipase (C14), α-chymotrypsin, acid phosphatase, ß-galactosidase, ß-glucosidase etc. differentiate strain MEBiC13590T from Oricola cellulosilytica CC-AMH-0T. Based on this polyphasic taxonomic data, strain MEBiC13590T should be classified as representing a novel species in the genus Oricola for which the name Oricola thermophila sp. nov. is proposed . The type strain is MEBiC13590T (=KCCM 43313T=JCM 33661T).

Description of Luteithermobacter gelatinilyticus gen. nov., sp. nov., and Paremcibacter congregatus gen. nov., comb. nov. via reclassification of the genus Emcibacter.

Strain MEBiC09520T, which was isolated from a tidal sediment in Incheon, Korea, is a pale yellow, rod-shaped bacterium, cells of which are 0.4-0.5 µm in width and 1.5-2 µm in length. Strain MEBiC09520T shared 95.17 and 92.57% 16S rRNA gene sequence similarity with Emcibacter nanhaiensis and E. congregatus, respectively. It grew optimally at pH 6.0, at 55 °C and with 2.5-3.5% (w/v) NaCl. Its polar lipid components included phosphatidylethanolamine (PE), diphosphatidylglycerol (DPG), phosphatidylglycerol (PG), an unidentified phospholipid (PL), three unidentified aminolipids (ALs) and two unidentified lipids (L). The fatty acids C16:0, C19:0 cyclo ω8c, C14:0 2-OH and summed feature 8 (C18:1ω7c and/or C18:1ω6c) were predominantly present in its cell wall. Strain MEBiC09520T was thermophilic, while E. nanhaiensis and E. congregatus were mesophilic. Although E. nanhaiensis showed no nitrate reduction activity, MEBiC09520T and E. congregatus showed a positive reaction. These strains differed in carbohydrate utilization. In particular, E. congregatus was able to thrive on various carbohydrate substrates as compared to the other strains. The average nucleotide identity value was 69.92% between strain MEBiC09520T and E. congregatus ZYLT, 70.38% between E. congregatus ZYLT and E. nanhaiensis HTCJW17T, and 72.83% between strain MEBiC09520 and E. nanhaiensis HTCJW17T. Considering these differences, strain MEBiC09520T (=KCCM 43320T=MCCC 1K03920T) is suggested to represent and novel species of a new genus, Luteithermobacter gelatinilyticus gen. nov., sp. nov., and E. congregatus should be reclassified as Paremcibacter congregatus gen. nov., comb. nov.

Parashewanella tropica sp. nov., a mesophilic bacterium isolated from a marine sponge from Chuuk lagoon, Federated States of Micronesia, and emended description of the genus Parashewanella.

A mesophilic, straight-rod-shaped, non-flagellated bacterium, designated MEBiC05444T, was isolated from a marine sponge collected from Chuuk lagoon, Federated States of Micronesia. The strain was Gram-negative, catalase- and oxidase-positive, and facultative anaerobic. The isolate aerobically grew at 8-38 °C (optimum, 24-32 °C), pH 4.0-10.0 (pH 7.0-7.5) with an absolute requirement for Na+ up to 6 % (w/v) NaCl (2 %). Phylogenetic analyses based on 16S rRNA gene sequences revealed that MEBiC05444T belonged to the family Shewanellaceae, within the class Gammaproteobacteria. Strain MEBiC05444T showed highest 16S rRNA gene sequence similarity to Parashewanella curva C51T, followed by [Shewanella] irciniae UST040317-058T and Parashewanella spongiae HJ039T (98.9 %, 97.2 and 95.7 %, respectively). In the phylogenetic tree based on the 16S rRNA gene sequences, MEBiC05444T formed a cluster with P. curva C51T, but the average nucleotide identity value between the two strains was 82 %, thus confirming their separation at species level. The major fatty acids were iso-C15 : 0 (19.7 %), summed feature 3 (composed of C16 : 1 ω7c and/or C16 : 1ω6c; 16.1 %) and C17 : 1ω8c (10.2 %). The only detected respiratory quinone was ubiquinone Q-8. The major polar lipids were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, three unidentified aminoglycolipids, two unidentified glycolipids, an unidentified aminoglycophospholipid and an unidentified lipid. The genomic DNA G+C content of strain MEBiC05444T was 40.8 mol%. Based on the results of polyphasic analysis, the strain represents a novel species of the genus Parashewanella, distinct from P. curva C51T, [Shewanella]irciniae UST040317-058T and P. spongiae HJ039T for which the name Parashewanellatropica sp. nov. is proposed with type strain MEBiC05444T (=KCCM 43304T=JCM 16653T).

Roseithermus sacchariphilus gen. nov., sp. nov. and proposal of Salisaetaceae fam. nov., representing new family in the order Rhodothermales.

A novel bacterium with cells that were pinkish-cream-coloured, aerobic, rod-shaped, 0.62-1.00 µm wide and 2.3-3.3 µm long, designated as strain MEBiC09517T, was isolated from Buksung-Po, a small port in Incheon, Republic of Korea. Strain MEBiC09517T had low 16S rRNA gene sequence similarity to validly reported strains; among them, Rubrivirgaprofundi SAORIC-476T displayed highest sequence similarity (89.9 %). Nevertheless, the novel strain shared a phylogenetic line with members of the genus Rhodothermus, not the genus Rubrivirga. Optimum growth conditions of strain MEBiC09517T were at 50-55 °C, pH 7 and in 2.0-4.0 % salt concentration. Strain MEBiC09517T was found to be an obligate marine bacterium that requires KCl, MgCl2 and CaCl2 as well as NaCl for growth. A phosphatidylethanolamine, a diphosphatidylglycerol, three glycolipids and four unidentified lipids were the strain's predominant polar lipid components. The fatty acid of the cell wall mainly consisted of carbons with 16 or 18 chain lengths such as C16 : 0, C18 : 0, C18 : 1 and summed feature 3 (C16 : 1ω6c and/or C16 : 1ω7c). The predominant menaquinone was MK-7. The DNA G+C content is 68.65 mol%. Strain MEBiC09517T differs from genera of the order Rhodothermales in terms of fatty acid composition, growth conditions, and range of carbon source utilization. Based on phylogenetic analysis using the strain's 16S rRNA gene sequence and results of physiological tests, strain MEBiC09517T (KCCM=43267T, JCM=32374T) is proposed as Roseithermus sacchariphilus gen. nov., sp. nov. Additionally, the novel family Salisaetaceae fam. nov. based on phylogenetic analysis and physiological characteristics is suggested.

Anaerosacchariphilus polymeriproducens gen. nov., sp. nov., an anaerobic bacterium isolated from a salt field.

A Gram-stain-negative oval-rod-shaped, spore-forming anaerobic bacterium, designated as strain MCWD5T, was isolated from sediment of a salt pond in the Republic of Korea (35° 7' 18″ N 126° 19' 4″ E). The 16S rRNA gene sequence analysis revealed that strain MCWD5T had low similarity values to members in the family Lachnospiraceae, such as Robinsoniella peoriensis PPC31T (94.8 %), Ruminococcusgauvreauii CCRI-16110T (94.2 %) and Lachnotalea glycerini DLD10T (94.0 %), and its phylogenetic position is unstable. The strain could grow at 20-42 °C (optimum, 38-42 °C), pH 5.5-10.0 (pH 7.0) and with 0-6 % (2.0 %) NaCl. Strain MCWD5T could not use nitrate, nitrite, sulfate or sulfite as electron acceptors. The strain could utilize various carbohydrates, such as arabinose, cellobiose, glucose, etc., and polymers such as pectin and starch. The major fatty acids of strain MCWD5T were C14 : 0, C16 : 0, C16 : 1ω7c, C18 : 1ω7c DMA and summed feature 8 (C17 : 1ω8c and/or C17 : 2), which was clearly different from those of related genera. The major polar lipids were diphosphatidyglycerol, phosphatidyglycerol and an unknown phospholipid. Based on the results of phylogenetic, physiologic and chemotaxonomic studies, Anaerosacchariphilus polymeriproducens gen. nov., sp. nov. with the type strain MCWD5T (=KCTC 15595T=DSM 105757T) is proposed in the family Lachnospiraceae.

Marinirhabdus citrea sp. nov., a marine bacterium isolated from a seaweed.

A gram-stain-negative, aerobic, rod-shaped (1.3-1.9×0.3-0.5 µm) and non-motile marine bacterium, designated MEBiC09412T, was isolated from seaweed collected at Yeonggwang County, South Korea. 16S rRNA gene sequence analysis demonstrated that strain MEBiC09412T shared high sequence similarity with Marinirhabdus gelatinilytica NH83T (95.4 %). Growth was observed at 17-38 °C (optimum 30 °C), at pH 4.0-8.5 (optimum pH 7.0) and with 0.5-6.0 % (w/v; optimum 2.5 %) NaCl. The predominant cellular fatty acids were iso-C15 : 0 (27.4 %), iso-C15 : 1 G (9.6 %), anteiso-C15 : 0 (14.6 %), iso-C16 : 0 (6.2 %), iso-C17 : 0 3OH (13.2 %) and summed feature 3 (comprising C16 : 1ω6c and/or C16 : 1ω7c; 7.4 %). The DNA G+C content was determined to be 43.1 mol%, while the major respiratory quinone was menaquinone-6. Several phenotypic characteristics such as indole production, the oxidizing patterns of several carbohydrtaes (of glucose, fructose, sucrose, maltose, mannose etc.) and organic acids, and the enzyme activities of α-chymotrypsin and α-glucosidase differentiated strain MEBiC09412T from M. gelatinilytica NH83T. On the basis of this polyphasic taxonomic data, strain MEBiC09412T should be classified as a novel species of the genus Marinirhabduswith the suggested name Marinirhabdus citrea sp. nov. The type strain is MEBiC09412T (=KCCM 43216T=JCM 31588T).

Flavobacterium sediminis sp. nov., a starch-degrading bacterium isolated from tidal flat sediment.

A yellow-pigmented bacterium with the ability to degrade starch, designated MEBiC07310T, was isolated from tidal flat sediment collected in Taean County, Republic of Korea. Phylogenetic analysis based on the 16S rRNA gene sequence indicated that strain MEBiC07310T was affiliated with the genus Flavobacterium in the phylum Bacteroidetes and showed that the strain was most closely related to Flavobacterium haoranii LQY-7T (96.8 % similarity), followed by Flavobacterium indicum GPTSA 100-9T (95.2 %) and Flavobacterium urocaniciphilum YIT 12746T (94.6 %). Genome-based analysis of the average nucleotide identity (ANI) and in silico DNA-DNA hybridization (DDH) of strain MEBiC07310T compared with F. haoranii LQY-7T and F. indicum GPTSA 100-9T yielded ANI values of 77.0 and 73.3 % and DDH values of 18.0±2.7 and 16.1±3.6 %, respectively. The DNA G+C content of strain MEBiC07310T was 35.2 mol%. Cells of the strain were aerobic, Gram-stain-negative and rod-shaped, and negative for flexirubin-type pigments. Growth was observed at 17-43 °C (optimum 32 °C), at pH 5.0-8.0 (optimum pH 7.0) and with 0-3 % (w/v) NaCl (optimum 1 %). The major fatty acids (>10 %) of strain MEBiC07310T were iso-C15 : 0, iso-C17 : 0 3-OH, summed feature 1 (iso-C15 : 1 H and/or C13 : 0 3-OH) and summed feature 3 (C16 : 1ω6c and/or C16 : 1ω7c). The major respiratory quinone was menaquinone MK-6. Based on its phenotypic and genotypic characteristics, strain MEBiC07310T should be classified as representing a novel species of the genus Flavobacterium, for which the name Flavobacterium sediminis sp. nov. is proposed. The type strain is MEBiC07310T (=KCTC 62132T=JCM 32291T).

Euzebyella algicola sp. nov., a marine bacterium of the family Flavobacteriaceae, isolated from green algae.

A Gram-negative, yellow-pigmented, non-flagellated, gliding, rod-shaped and aerobic bacterium, designated MEBiC 12267T, was isolated from green algae of Jeju Island. 16S rRNA gene sequence analysis revealed that the strain MEBiC 12267T was affiliated to the genus Euzebyella of the family Flavobacteriaceae and showed the highest similarity to Euzebyella marina KCTC 42440T (98.5 %). The DNA-DNA relatedness value of strain MEBiC 12267T with E. marina KCTC 42440T was 25 %. Growth was observed at 10-37 °C (optimum, 30-33 °C), at pH 6.0-9.5 (optimum, 8.0-8.5) and with 0.5-9.0 % (w/v) NaCl (optimum, 2.5-3.5 %). The predominant cellular fatty acids were iso-C15 : 0, iso-C15 : 1 G and iso-C17 : 0 3-OH. The major respiratory quinone was MK-6. Polar lipids included phosphatidylethanolamine, seven unidentified lipids and two unidentified aminolipids. The DNA G+C content was 40.7 mol%. On the basis of the data from the polyphasic taxonomic study, it was concluded that the strain MEBiC 12267T represents a novel species within the genus Euzebyella, for which the name Euzebyella algicola sp. nov. is proposed. The type strain of E. algicola is MEBiC 12267T (=KCCM 43264T=JCM 32170T).

Corallibacterium pacifica gen. nov., sp. nov., a Novel Bacterium of the Family Vibrionaceae Isolated from Hard Coral.

A gram-negative, rod-shaped, motile, oxidase- and catalase-positive, non-pigmented marine bacterium, designated strain OS-11M-2T, was isolated from a coral sample collected from the Osakura coastal area in Micronesia. Phylogenetic analysis based on 16S ribosomal RNA (rRNA) gene sequences indicated that strain OS-11M-2T is a member of the family Vibrionaceae, its closest neighbors being Photobacterium damselae subsp. piscicida NCIMB 2058T (94.9%), Photobacterium damselae subsp. damselae CIP 102761T (94.75%), Grimontia marina IMCC5001T (94.5%), Enterovibrio coralii LMG 22228T (94.5%), and Grimontia celer 96-237T (94.5%). The major cellular fatty acids were summed feature 3 (21.4%), summed feature 8 (18.5%), iso-C16:0 (13.8%), and C16:0 (11.9%). The major respiratory quinone of the bacterium was ubiquinone-8 (Q-8) and its major polar lipid phosphatidylethanolamine. Six amino lipids, two phospholipids, and one polar lipid, all unidentified, were detected. The DNA G+C content was 49.7 mol%. The 16S rRNA gene sequence of OS-11M-2T was registered in GenBank under accession number MF359550. On the basis of phenotypic, genotypic, and phylogenetic analyses, strain OS-11M-2T represents a novel genus of the family Vibrionaceae, for which we propose the name Corallibacterium pacifica gen. nov., sp. nov., with the type strain of the type species being OS-11M-2T (= KCCM 43265T). The digital protologue database (DPD) taxon number for strain OS-11M-2T is GA00041.

Echinicola strongylocentroti sp. nov., isolated from a sea urchin Strongylocentrotus intermedius.

A yellowish-orange-pigmented marine bacterium, designated MEBiC08714T was isolated from a sea urchin Strongylocentrotus intermedius collected at the west edge of the East Sea of Korea. Phylogenetic analysis based on the 16S rRNA gene sequences indicated that MEBiC08714T was affiliated with the genus Echinicola and that the strain was most closely related to Echinicola vietnamensis KCTC 12713T (96.9 %), followed by 'Echinicola shivajiensis' JCM 17847 (96.3 %), Echinicola jeungdonensis KCTC 23122T (96.1 %), and Echinicola pacifica KCTC 12368T (95.0 %). Cells were strictly aerobic, Gram-stain-negative, rod shaped, flexirubin-type pigments-negative and motile by gliding. Growth was observed at 20-35 °C (optimum 25 °C), at pH 6-11 (optimum pH 7.0), and with 0-13 % NaCl (optimum 2 %). This strain was able to hydrolyze agar and starch. The polar lipids of MEBiC08714T contained phosphatidylethanolamine, an unidentified phospholipid, and four unidentified lipids. The major fatty acids were iso-C15 : 0 (27.5 %), iso-C17 : 0 3-OH (11.5 %), anteiso-C15 : 0 (5.2 %), summed feature 3 (C16:1ω7c and/or C16:1ω6c, 20.3 %) and summed feature 9 (iso-C17 : 1ω9c and/or10-methyl C16 : 06, 6.3 %). The DNA G+C content was 44.2 mol% and the major respiratory quinone was MK-7. On the basis of these polyphasic taxonomic data, MEBiC08714T represents a novel species of the genus Echinicola, for which the name Echinicola strongylocentroti sp. nov. is proposed. The type strain is MEBiC08714T (=KCTC 52052T=JCM 31307T).

Oleiagrimonas citrea sp. nov., a marine bacterium isolated from tidal flat sediment and emended description of the genus Oleiagrimonas Fang et al. 2015 and Oleiagrimonas soli.

A Gram-stain-negative, aerobic, rod-shaped (1.4-3.6×0.4-0.6 µm) and motile marine bacterium, designated as MEBiC09124T, was isolated from tidal flat sediment of Suncheon Bay, South Korea. 16S rRNA gene sequence analysis revealed that strain MEBiC09124T showed high similarity to Oleiagrimonas soli 3.5XT (96.7 %). Growth was observed at 18-38 °C (optimum 30 °C), at pH 4.0-8.5 (optimum pH 7.5) and with 0-6 % (w/v) (optimum 2.5 %) NaCl. The predominant cellular fatty acids were iso-C15 : 0, iso-C16 : 0, iso-C17 : 0 and summed feature 9 (comprising 10-methyl C16 : 0 and/or iso-C17 : 1ω9c). The DNA G+C content was 66.1 mol%. The major respiratory quinone was Q-8. Biochemical characteristics such as production of acetoin and enzyme activities of trypsin, α-chymotrypsin and N-acetyl-ß-glucosaminidase differentiated strain MEBiC09124T from O. soli 3.5XT. On the basis of data from this polyphasic taxonomic study, strain MEBiC09124T (=KCCM 43131T=JCM 30904T) is classified as the type strain of a novel species in the genus Oleiagrimonas, for which the name Oleiagrimonas citrea sp. nov. is proposed. Emended descriptions of the genus Oleiagrimonas and Oleiagrimonas soli are also given.

Formate-driven growth coupled with H(2) production.

Although a common reaction in anaerobic environments, the conversion of formate and water to bicarbonate and H(2) (with a change in Gibbs free energy of ΔG° = +1.3 kJ mol(-1)) has not been considered energetic enough to support growth of microorganisms. Recently, experimental evidence for growth on formate was reported for syntrophic communities of Moorella sp. strain AMP and a hydrogen-consuming Methanothermobacter species and of Desulfovibrio sp. strain G11 and Methanobrevibacter arboriphilus strain AZ. The basis of the sustainable growth of the formate-users is explained by H(2) consumption by the methanogens, which lowers the H(2) partial pressure, thus making the pathway exergonic. However, it has not been shown that a single strain can grow on formate by catalysing its conversion to bicarbonate and H(2). Here we report that several hyperthermophilic archaea belonging to the Thermococcus genus are capable of formate-oxidizing, H(2)-producing growth. The actual ΔG values for the formate metabolism are calculated to range between -8 and -20 kJ mol(-1) under the physiological conditions where Thermococcus onnurineus strain NA1 are grown. Furthermore, we detected ATP synthesis in the presence of formate as a sole energy source. Gene expression profiling and disruption identified the gene cluster encoding formate hydrogen lyase, cation/proton antiporter and formate transporter, which were responsible for the growth of T. onnurineus NA1 on formate. This work shows formate-driven growth by a single microorganism with protons as the electron acceptor, and reports the biochemical basis of this ability.

Kiloniella spongiae sp. nov., isolated from a marine sponge and emended description of the genus Kiloniella Wiese et al. 2009 and Kiloniella laminariae.

A Gram-reaction-negative, aerobic, rod-shaped and non-motile marine bacterium, designated MEBiC09566(T) was isolated from a sponge collected at Uljin County in the coastal area of the East Sea (36° 55' N, 129° 25' E), Korea. The 16S rRNA gene sequence analysis revealed that strain MEBiC09566(T) showed the highest similarity with the Kiloniella laminariae LD81(T) (96.7%). Growth was observed at 11-31 °C (optimum 25 °C), at pH 6.0-8.5 (optimum pH 7.0) and with 0-6% (optimum 2.5%) NaCl. The predominant cellular fatty acids were summed feature 8 (comprised of C18:1ω7c/C18:1ω6c) and summed feature 3 (comprised of C16:1ω7c and/or C16:1ω6c). The DNA G+C content is 44.6 mol%. The major respiratory quinone is Q-9. Phosphatidylethanolamine, phosphatidylglycerol, an unidentified lipid, two unidentified aminophospholipids and one unidentified aminolipid were detected as major polar lipids. On the basis of this polyphasic taxonomic data, it is concluded that strain MEBiC09566(T) should be classified as representing a novel species in the genus Kiloniella and the name proposed is Kiloniella spongiae sp. nov. The type strain is MEBiC09566(T) ( = KCCM 43040(T) = JCM 19930(T)). Emended descriptions of the genus Kiloniella Wiese et al. 2009 and Kiloniella laminariae are also given.

Pseudomaricurvus alcaniphilus sp. nov., a marine bacterium isolated from tidal flat sediment and emended descriptions of the genus Pseudomaricurvus, Pseudomaricurvus alkylphenolicus Iwaki et al. 2014 and Maricurvus nonylphenolicus Iwaki et al. 2012.

A novel Gram-reaction-negative, rod-shaped, aerobic and motile strain, designated MEBiC06469T, was isolated from tidal flat sediment of the Taean province, South Korea. Strain MEBiC06469T produced ivory-coloured colonies on marine agar 2216 medium and could degrade carboxymethyl-cellulose. On the basis of 16S rRNA gene sequence similarity, the closest relative was Pseudomaricurvus alkylphenolicus KU41GT with 96.5 % similarity. The isolate was catalase-positive but oxidase-negative. Growth was observed at 16-38 °C (optimum, 32 °C), at pH 6.0-9.0 (optimum, pH 7.5) and in the presence of 0.0-8.0 % (w/v) NaCl (optimum, 1.5 %). The only isoprenoid quinone was Q-8.The dominant fatty acids were summed feature 3 (comprised of C15 : 0 2-OH and/or C16 : 1ω7c; 20.4 %) and C17 : 1ω8c (30.9 %), summed feature 8 (comprised of C18 : 1ω7c and/or C18 : 1ω6c; 9.5 %), C16 : 0 (9.0 %), C15 : 1ω8c (5.3 %), and C11 : 0 3-OH (5.2 %). Based on these phenotypic properties and phylogenetic data, strain MEBiC06469T should be classified as a novel species within the genus Pseudomaricurvus for which the name Pseudomaricurvus alcaniphilus sp. nov. is proposed. The type strain is MEBiC06469T ( = KCCM 42976T = JCM 18313T). Emended descriptions of the genus Pseudomaricurvus, Pseudomaricurvus alkylphenolicusIwaki et al. 2014, and Maricurvus nonylphenolicusIwaki et al. 2012 are also provided.

Amphritea spongicola sp. nov., isolated from a marine sponge, and emended description of the genus Amphritea.

A Gram-stain-negative, rod-shaped (1.2-2.1 µm × 0.8-0.9 µm), flagellated and motile marine bacterium, designated MEBiC05461T, was isolated from a marine sponge inhabiting Micronesia. Strain MEBiC05461T was oxidase-negative and catalase-positive. Growth was observed at 8.0-35.6 °C (optimum 30.0 °C), at pH 5.0-9.0 (optimum pH 7.0) and with 1.5-6.0 % (w/v, optimum 2.0-2.5 %) NaCl. 16S rRNA gene sequence analysis revealed that strain MEBiC05461T showed high similarity to members of the genus Amphritea (96.4-96.6 %). The predominant cellular fatty acids were C16:0 (23.9 %), summed feature 3 (C16:1ω7c and/or C16:1ω6c; 39.7 %) and summed feature 8 (C18:1ω7c and/or C18:1ω6c; 22.0 %). The DNA G+C content was 48.5 mol%. The major respiratory quinone was Q-8.Phosphatidylethanolamine, phosphatidylglycerol, one unidentified glycolipid, one unidentified aminolipid, one unidentified glycophospholipid and two unidentified lipids were detected as the major polar lipids. On the basis of the data from this polyphasic taxonomic study, strain MEBiC05461T should be classified as a representative of a novel species in the genus Amphritea, and the name proposed is Amphritea spongicola sp. nov. The type strain is MEBiC05461T ( = KCCM 42943T = JCM 16668T). Emendations of the genus Amphritea and species Amphritea atlanticaGärtner et al. 2008 and Amphritea balenaeMiyazaki et al. 2008 are were also given.

Structure-based investigation into the functional roles of the extended loop and substrate-recognition sites in an endo-ß-1,4-D-mannanase from the Antarctic springtail, Cryptopygus antarcticus.

Endo-ß-1,4-D-mannanase from the Antarctic springtail, Cryptopygus antarcticus (CaMan), is a cold-adapted ß-mannanase that has the lowest optimum temperature (30°C) of all known ß-mannanases. Here, we report the apo- and mannopentaose (M5) complex structures of CaMan. Structural comparison of CaMan with other ß-mannanases from the multicellular animals reveals that CaMan has an extended loop that alters topography of the active site. Structural and mutational analyses suggest that this extended loop is linked to the cold-adapted enzymatic activity. From the CaMan-M5 complex structure, we defined the mannose-recognition subsites and observed unreported M5 binding site on the surface of CaMan.