Halocynthiibacter namhaensis gen. nov., sp. nov., a novel alphaproteobacterium isolated from sea squirt Halocynthia roretzi

A Gram-negative, non-motile and rod-shaped bacterial strain, designated RA2-3^T, was isolated from a sea squirt (Halocynthia roretzi) collected from the South Sea, Korea, and its taxonomic position was investigated by using a polyphasic approach. Strain RA2-3^T was observed to grow optimally at 25 °C, at pH 7.0–7.5 and in the presence of 2 % (w/v) NaCl. Strain RA2-3^T exhibited the highest 16S rRNA gene sequence similarity values to the type strains of Litoreibacter meonggei (95.7 %), Planktotalea frisia (95.6 %), Thalassobius gelatinovorus (95.5 %) and Pelagicola litoralis (95.4 %). A neighbour-joining phylogenetic tree based on 16S rRNA gene sequences revealed that strain RA2-3^T clustered with the type strains of Planktotalea frisia, Pelagicola litoralis, Pacificibacter maritimus and Roseovarius marinus. Strain RA2-3^T was found to contain Q-10 as the predominant ubiquinone and C_18:1 ω7c as the major fatty acid. The major polar lipids detected in strain RA2-3^T were phosphatidylcholine, phosphatidylglycerol, one unidentified aminolipid and one unidentified lipid. The DNA G+C content of strain RA2-3^T was 52.9 mol%. On the basis of the phylogenetic, chemotaxonomic and phenotypic properties, strain RA2-3^T is considered to represent a new genus and species within the family Rhodobacteraceae, for which the name Halocynthiibacter namhaensis gen. nov., sp. nov. is proposed. The type strain of H. namhaensis is RA2-3^T (=KCTC 32362^T=NBRC 109999^T).     

Ruegeria meonggei sp. nov., an alphaproteobacterium isolated from ascidian Halocynthia roretzi

A Gram-negative, strictly aerobic, non-flagellated and rod-shaped bacterial strain, designated MA-E2-3^T, was isolated from an ascidian (Halocynthia roretzi) collected from the South Sea, South Korea. Strain MA-E2-3^T was found to grow optimally at 30 °C, at pH 7.0–8.0 and in the presence of 2.0–3.0 % (w/v) NaCl. A neighbour-joining phylogenetic tree based on 16S rRNA gene sequences revealed that strain MA-E2-3^T fell within the clade comprising Ruegeria species, clustering consistently with the type strain of Ruegeria halocynthiae, with which it exhibited 98.2 % sequence similarity. Sequence similarities to the type strains of the other recognized Ruegeria species were 94.7–97.7 %. Strain MA-E2-3^T was found to contain Q-10 as the predominant ubiquinone and C_18:1 ω7c as the predominant fatty acid. The major polar lipids of strain MA-E2-3^T were identified as phosphatidylcholine, phosphatidylglycerol, phosphatidylethanolamine, one unidentified aminolipid and one unidentified lipid. The DNA G+C content of strain MA-E2-3^T was determined to be 58.0 mol%. Mean DNA–DNA relatedness values between strain MA-E2-3^T and the type strains of four phylogenetically closely related Ruegeria species were in the range of 13–23 %. The differential phenotypic properties, together with the phylogenetic and genetic distinctiveness, revealed that strain MA-E2-3^T is separated from other Ruegeria species. On the basis of the data presented, strain MA-E2-3^T (=KCTC 32450^T = CECT 8411^T) represents a novel species of the genus Ruegeria, for which the name Ruegeria meonggei sp. nov. is proposed.     

Tenacibaculum halocynthiae sp. nov., a member of the family Flavobacteriaceae isolated from sea squirt Halocynthia roretzi

A Gram-negative, non-spore-forming, aerobic, non-flagellated, non-gliding and rod-shaped bacterial strain, designated P-R2A1-2^T, was isolated from sea squirt (Halocynthia roretzi) collected from the South Sea, Korea. It grew optimally at 25–28 °C, at pH 7.0–8.0 and in the presence of 2 % (w/v) NaCl. Neighbour-joining phylogenetic tree based on 16S rRNA gene sequences revealed that the strain fell within the clade comprising Tenacibaculum species. Strain P-R2A1-2^T exhibited the highest 16S rRNA gene sequence similarity values of 97.6, 97.2 and 97.0 % to Tenacibaculum aestuarii SMK-4^T, T. lutimaris TF-26^T and T. aiptasiae a4^T, respectively, and of 94.5–96.8 % to the type strains of the other Tenacibaculum species. Strain P-R2A1-2^T contained MK-6 as the predominant menaquinone and C_16:1 ω7c and/or iso-C_15:0 2-OH, iso-C_15:0 3-OH and iso-C_15:0 as the major fatty acids. The DNA G + C content of strain P-R2A1-2^T was 30.7 mol % and its DNA–DNA relatedness values with the type strains of T. aestuarii, T. lutimaris and T. aiptasiae were 17 ± 4.2, 21 ± 6.1 and 16 ± 5.2 %, respectively. Differential phenotypic properties, together with the phylogenetic and genetic distinctiveness, revealed that the novel strain is separate from other Tenacibaculum species. On the basis of the data presented, strain P-R2A1-2^T is considered to represent a novel species of the genus Tenacibaculum, for which the name Tenacibaculum halocynthiae sp. nov. is proposed. The type strain is P-R2A1-2^T (=KCTC 32262^T = CCUG 63681^T).     

Thalassomonas fusca sp. nov., a novel gammaproteobacterium isolated from tidal flat sediment

A Gram-negative, aerobic, non-motile, dark brown-coloured and rod-shaped bacterial strain, designated G-MB1^T, was isolated from a tidal flat sediment of the South Sea, South Korea. Strain G-MB1^T was found to grow optimally at 25 °C, at pH 7.0–8.0 and in the presence of 2.0 % (w/v) NaCl. A neighbour-joining phylogenetic tree based on 16S rRNA gene sequences revealed that strain G-MB1^T fell within the clade comprising Thalassomonas species, clustering with the type strains of Thalassomonas agarivorans, Thalassomonas loyana, Thalassomonas ganghwensis and Thalassomonas agariperforans, with which it exhibited 16S rRNA gene sequence similarity values of 96.0–96.9 %. The 16S rRNA gene sequence similarity values between strain G-MB1^T and the type strains of the other Thalassomonas species were 94.6–95.1 %. Strain G-MB1^T was found to contain Q-8 as the predominant ubiquinone and C_16:0, C_17:1 ω8c, C_16:1 ω9c, C_12:0 3-OH and summed feature 3 (C_16:1 ω7c and/or C_16:1 ω6c) as the major fatty acids. The major polar lipids of strain G-MB1^T were phosphatidylglycerol, phosphatidylethanolamine and one unidentified aminolipid. The DNA G+C content of strain G-MB1^T was determined to be 42.4 mol%. Differential phenotypic properties, together with the phylogenetic distinctiveness, revealed that strain G-MB1^T is separated from other Thalassomonas species. On the basis of the data presented, strain G-MB1^T is considered to represent a novel species of the genus Thalassomonas, for which the name Thalassomonas fusca sp. nov. is proposed. The type strain is G-MB1^T (=KCTC 32499^T = NBRC 109830^T).     

Echinimonas agarilytica gen. nov., sp. nov., a new gammaproteobacterium isolated from the sea urchin Strongylocentrotus intermedius

A novel Gram-negative, facultatively anaerobic and motile bacterial strain, designated KMM 6351^T, was isolated from the sea urchin Strongylocentrotus intermedius and examined using a polyphasic taxonomic approach. A phylogenetic analysis based on 16S rRNA gene sequencing revealed that the strain formed a distinct phyletic line in the class Gammaproteobacteria and was most closely related to the genera Aliivibrio, Photobacterium and Vibrio. Strain KMM 6351^T grows at 4–40 °C and with 0.5–12 % NaCl and decomposes aesculin, agar, gelatin, starch, chitin and DNA. The DNA G+C content of the strain was determined to be 46.1 mol%. The prevalent fatty acids were found to be C_16:0, C_18:1 ω7c, C_12:0 3-OH and summed feature 3 (comprising C_16:1 ω7c and/or iso-C_15:0 2-OH fatty acids). The major polar lipids were determined to be diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and an unidentified aminolipid. The predominant ubiquinone was found to be Q-8. The results of the phenotypic, chemotaxonomic and genotypic analyses clearly indicated that the novel strain should be assigned to a new genus and species within the class γ-Proteobacteria for which the name Echinimonas agarilytica gen. nov., sp. nov. is proposed. The type strain is KMM 6351^T (=KCTC 22996^T = LMG 25420^T).     

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

A Gram-negative, aerobic, non-motile and ovoid or rod-shaped bacterial strain, GGW-M5^T, was isolated from seawater on the southern coast in Korea, and its taxonomic position was investigated by using a polyphasic approach. Strain GGW-M5^T grew optimally at pH 7.0–8.0, at 30 °C and in the presence of 2 % (w/v) NaCl. A neighbour-joining phylogenetic tree based on 16S rRNA gene sequences revealed that strain GGW-M5^T belonged to the genus Glaciecola, joining the cluster comprising the type strains of G. agarilytica, G. arctica, G. chathamensis, G. mesophila, G. polaris and G. psychrophila, with which it exhibited 16S rRNA gene sequence similarity values of 95.9–96.7 %. Strain GGW-M5^T exhibited sequence similarity values of 93.2–94.8 % to the type strains of the other Glaciecola species. Strain GGW-M5^T contained Q-8 as the predominant ubiquinone and C_16:1 ω7c and/or iso-C_15:0 2-OH, C_16:0 and C_14:0 2-OH as the major fatty acids. Major polar lipids were phosphatidylglycerol, phosphatidylethanolamine and diphosphatidylglycerol. The DNA G+C content was 42.4 mol%. Differential phenotypic properties, together with the phylogenetic distinctiveness, demonstrated that strain GGW-M5^T could be distinguished from other Glaciecola species. On the basis of the data presented, strain GGW-M5^T is considered to represent a novel species of the genus Glaciecola, for which the name Glaciecola aquimarina sp. nov. is proposed. The type strain is GGW-M5^T (=KCTC 32108^T = CCUG 62918^T).     

Spongiibacter pelagi sp. nov., a marine gammaproteobacterium isolated from coastal seawater

A novel gammaproteobacterium, designated as KMU-158^T, was isolated from seawater collected on the coastline of Dadaepo in the Republic of Korea, and characterized using a polyphasic taxonomic approach. Strain KMU-158^T was Gram-staining-negative, pale beige-colored, strictly aerobic, rod-shaped, motile, and chemoorganoheterotrophic. The novel isolate was able to grow at 0–3% NaCl concentrations (w/v), pH 6.5–9.5, and 15–40 °C. The analysis based on 16S rRNA gene sequences indicated that strain KMU-158^T belongs to the family Spongiibacteraceae and shared the highest similarity with Spongiibacter tropicus CL-CB221^T (96.1%). The major cellular fatty acids were summed feature 3 (C_16:1 ω7c and/or C_16:1 ω6c) and C_17:1 ω8c. The only respiratory quinone was identified as ubiquinone-8. The polar lipids of strain KMU-158^T contained phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, and two unidentified lipids. The assembled draft genome size of strain KMU-158^T was 3.29 Mbp with a DNA G?+?C content of 51.3%. The average nucleotide identity, digital DNA–DNA hybridization, and average amino acid identity values of KMU-158^T and the representatives of the genus Spongiibacter were found to be 78.5–79.1%, 13.8–14.1%, and 66.6–66.8%, respectively. From the distinct phenotypic, phylogenetic, genomic, and chemotaxonomic properties, the strain KMU-158^T is considered to represent a novel species of the genus Spongiibacter, for which the name Spongiibacter pelagi sp. nov. is proposed. The type strain of the species S. pelagi sp. nov. is KMU-158^T (=?KCCM 90448^T?=?NBRC 114307^T).

     

Simiduia aestuariiviva sp. nov., a gammaproteobacterium isolated from a tidal flat sediment

A Gram-stain negative, aerobic, motile and rod-shaped bacterial strain, designated J-MY2^T, was isolated from a tidal flat sediment of the South Sea, South Korea. Strain J-MY2^T was found to grow optimally at 30 °C, at pH 7.0–8.0 and in the presence of 2.0 % (w/v) NaCl. Phylogenetic trees based on 16S rRNA gene sequences revealed that strain J-MY2^T forms a cluster with the type strains of Simiduia species. Strain J-MY2^T exhibited 16S rRNA gene sequence similarity values of 97.62–98.77 % to the type strains of four Simiduia species and of <92.95 % sequence similarity to the type strains of the other recognized species. Strain J-MY2^T was found to contain Q-8 as the predominant ubiquinone and summed feature 3 (C_16:1 ω7c and/or C_16:1 ω6c), C_16:0, C_18:1 ω7c and C_17:1 ω8c as the major fatty acids. The major polar lipids of strain J-MY2^T were identified as phosphatidylethanolamine, phosphatidylglycerol, three unidentified glycolipids and one unidentified lipid. The DNA G+C content of strain J-MY2^T was determined to be 54.8 mol% and its mean DNA–DNA relatedness values with the type strains of the four Simiduia species were in the range 21–34 %. The differential phenotypic properties, together with the phylogenetic and genetic distinctiveness, revealed that strain J-MY2^T is separated from other Simiduia species. On the basis of the data presented, strain J-MY2^T is considered to represent a novel species of the genus Simiduia, for which the name Simiduia aestuariiviva sp. nov. is proposed. The type strain is J-MY2^T ( = KCTC 42073^T = CECT 8571^T).     

Shewanella litorisediminis sp. nov., a gammaproteobacterium isolated from a tidal flat sediment

A Gram-negative, facultatively anaerobic, non-motile and rod-shaped bacterial strain, designated SMK1-12^T, was isolated from a tidal flat sediment on the western coast of Korea. Phylogenetic analyses based on 16S rRNA and gyrB gene sequences showed that strain SMK1-12^T belonged to the genus Shewanella, clustering with the type strain of Shewanella amazonensis. Strain SMK1-12^T exhibited the highest 16S rRNA gene sequence similarity value (97.0 %) and the highest gyrB sequence similarity value (87.8 %) to S. amazonensis SB2B^T, respectively. Strain SMK1-12^T contained simultaneously both menaquinones and ubiquinones; the predominant menaquinone was MK-7 and the predominant ubiquinones were Q-7 and Q-8. The major fatty acids (>10 % of the total fatty acids) detected in strain SMK1-12^T were the MIDI system summed feature 3 (iso-C_15:0 2-OH and/or C_16:1 ω7c), iso-C_15:0, C_17:1 ω8c and C_16:0. The DNA G+C content of strain SMK1-12^T was 58.0 mol% and its mean DNA–DNA relatedness value with S. amazonensis ATCC 700329^T was 15 ± 4.6 %. Differential phenotypic properties, together with the phylogenetic and genetic distinctiveness, revealed that strain SMK1-12^T is distinguishable from recognized Shewanella species. On the basis of the data presented, strain SMK1-12^T is considered to represent a novel Shewanella species, for which the name Shewanella litorisediminis sp. nov. is proposed. The type strain is SMK1-12^T (=KCTC 23961^T = CCUG 62411^T).     

Rhodanobacter fulvus sp. nov., a beta-galactosidase-producing gammaproteobacterium

A taxonomic study was carried out on a bacterial strain designated as Jip2T isolated from a soil sample mixed with rotten rice straw. It was a Gram-negative, aerobic, motile, and rod-shaped bacterium. It grew well on nutrient agar medium and utilized a fairly narrow spectrum of carbon source. The G+C content of the genomic DNA was 65.3 mol%. The major ubiquinone was Q-8. The major fatty acids were branched fatty acids, especially large amounts of iso C15:0 and iso C17:1 w9c were detected in the cells grown on TSA agar for 24 h. Comparative 16S rDNA study showed a clear affiliation of this bacterium to the genus Rhodanobacter. The 16S rDNA sequence of strain Jip2T showed 96.4% sequence similarity to that of Rhodanobacter lindaniclasticus RP5575T. On the basis of phenotypic characteristics and 16S rDNA sequence analysis, strain Jip2T is clearly distinct from Rhodanobacter lindaniclasticus. We propose the name Rhodanobacter fulvus sp. nov. for strain Jip2T (=IAM 15025T=KCTC 12098T).     

Arenimonas aquaticum sp. nov., a member of the gammaproteobacterium, isolated from a freshwater reservoir

A novel bacterial strain, designated NA-09^T, was isolated from a freshwater sample collected from the Cheonho reservoir, Republic of Korea. Colonies were creamy-white pigmented, translucent, and circular with convex shape. The isolate was Gram-staining negative, strictly aerobic, motile, and rod-shaped. The 16S rRNA gene sequence analysis revealed that strain NA-09^T belonged to the genus Arenimonas and showed the highest sequence similarities with Arenimonas malthae CC-JY-1^T (95.4%), A. oryziterrae YC6267^T (94.9%), A. composti P2-12-1^T (94.8%), and A. donghaensis H03-R19^T (94.1%). The major fatty acids were iso-C_16:0 (20.8%), iso-C_15:0 (16.9%), summed feature 1 (13.2%), and iso-C_16:1 ω7c alcohol (10.2%). The major isoprenoid quinone of the isolate was ubiquionone-8. On the basis of the data from the polyphasic characterization, the strain NA-09^T represents a novel species, for which the name Arenimonas aquaticum sp. nov. is proposed (type strain NA-09^T =KACC 14663^T =NBRC 106550^T).     

Isolation and characterization of polymorphic microsatellite DNA markers in the sea squirt Halocynthia roretzi

The sea squirt Halocynthia roretzi is an important marine food resource species that is found in the waters around Korea. We describe the isolation and characterization of 13 new polymorphic microsatellite loci in 96 sea squirt samples that were collected from the marine environment of Samcheok on the east coast of Korea. The number of alleles that were observed for each locus ranged from six to 32, and the value of expected and observed heterozygosities was 0.504-0.922 and 0.396-0.813, respectively. These markers will be useful tools for future population studies.     

Effects of dietary sea squirt (Halocynthia roretzi) on lipid metabolism in rats

The effect of dietary sea squirt ( Halocynthia roretzi) on lipid metabolism in rats was investigated. Rats were fed sea squirt muscle (Experiment 1); sea squirt muscle, defatted sea squirt muscle and its hexane extract (Experiment 2); and whole body sea squirt and its parts as muscle or viscera (Experiment 3). All of the diets contained the same levels of protein (20%) and lipid (7%). In experiment 1, serum total cholesterol (T-Ch), very-low-density lipoprotein plus low-density lipoprotein (VLDL+LDL)-Ch, triglyceride (TG), phospholipid (PL) and nonesterified fatty acid (NEFA) levels were reduced by 20% dietary sea squirt muscle ingestion; steroid excretions into feces were enhanced by the same diet. In experiment 2, serum T-Ch, (VLDL+LDL)-Ch, TG, PL and NEFA levels were significantly reduced and steroid excretions into feces were significantly enhanced by ingestion of the sea squirt muscle hexane extract. Ingestion of defatted sea squirt muscle also reduced these serum lipid levels, but not as much as did that of whole sea squirt muscle. In experiment 3, serum T-Ch and HDL-Ch levels were significantly elevated by the 10% sea squirt viscera ingestion.     

Arthrospiribacter ruber gen. nov., sp. nov., a novel bacterium isolated from Arthrospira cultures

Polyphasic analysis of ten isolates of the red-pigmented bacteria isolated from ten Arthrospira cultures originating from different parts of the world is described. The 16S rRNA analysis showed <95 % identity with the known bacteria on public databases, therefore, additional analyses of fatty acids profiles, MALDI-TOF/MS, genome sequencing of the chosen isolate and following phylogenomic analyses were performed. Gram-stain-negative, strictly aerobic rods were positive for catalase, negative for oxidase, proteolytic and urease activity. Major fatty acids were 15 : 0 iso, 17:0 iso 3 OH and 17:1 iso w9c/16:0 10-methyl. The whole phylogenomic analyses revealed that the genomic sequence of newly isolated strain DPMB0001 was most closely related to members of Cyclobacteriaceae family and clearly indicated distinctiveness of newly isolated bacteria. The average nucleotide identity and in silico DNA–DNA hybridisation values were calculated between representative of the novel strains DPMB0001 and its phylogenetically closest species, Indibacter alkaliphilus CCUG57479 (LW1)^T (ANI 69.2 % is DDH 17.2 %) and Mariniradius saccharolyticus AK6^T (ANI 80.02 % isDDH 26.1 %), and were significantly below the established cut-off <94 % (ANI) and <70 % (isDDH) for species and genus delineation.The obtained results showed that the analysed isolates represent novel genus and species, for which names Arthrospiribacter gen nov. and Arthrospiribacter ruber sp. nov. (type strain DPMB0001 = LMG 31078 = PCM 3008) is proposed.