Seung-Jo Yang

Gaetbulibacter marinus sp. nov., isolated from coastal seawater, and emended description of the genus Gaetbulibacter.

A Gram-negative, yellow-coloured, chemoheterotrophic, non-motile, strictly aerobic, rod-shaped bacterium, designated IMCC1914(T), was isolated from coastal surface seawater of the Yellow Sea, Korea. The temperature, pH and NaCl ranges for growth were 3-37 degrees C, pH 8.0-11.0 and 0.5-4.0 %. The DNA G+C content of the strain was 38.1 mol% and the major cellular fatty acids were iso-C(15 : 1) (32.1 %), iso-C(15 : 0) (20.6 %) and iso-C(17 : 0) 3-OH (7.8 %). Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain IMCC1914(T) was related most closely to Gaetbulibacter saemankumensis SMK-12(T), with a sequence similarity of 96.2 %. On the basis of phylogenetic data and several distinct phenotypic characteristics, strain IMCC1914(T) (=KCCM 42380(T) =NBRC 102040(T)) could be assigned to the genus Gaetbulibacter as the type strain of a novel species, for which the name Gaetbulibacter marinus sp. nov. is proposed. In addition, an emended description of the genus Gaetbulibacter is presented.

Lutibacter flavus sp. nov., a marine bacterium isolated from a tidal flat sediment

A carotenoid-containing chemoheterotrophic bacterium, designated IMCC1507(T), was isolated from a tidal flat sediment of the Yellow Sea, Korea. Strain IMCC1507(T) was Gram-negative, yellow, obligately aerobic, non-motile and flexirubin-negative. 16S rRNA gene sequence analysis indicated that strain IMCC1507(T) belonged to the genus Lutibacter in the family Flavobacteriaceae and exhibited 96.1-97.3 % 16S rRNA sequence similarity with the type strains of described species of the genus Lutibacter. DNA-DNA relatedness between strain IMCC1507(T) and Lutibacter litoralis KCCM 42118(T) ranged from 3.5±2.2 % to 11.2±2.4 %, indicating that strain IMCC1507(T) represented a novel genomic species in the genus Lutibacter. Chemotaxonomic characteristics of the isolate, i.e. the DNA G+C content (31.4 mol%), iso-C15 : 0 3-OH, iso-C15 : 0, iso-C15 : 1 G and anteiso-C15 : 0 as the major fatty acids, MK-6 as the predominant menaquinone and phosphatidylethanolamine as the major polar lipid, were consistent with its assignment to the genus Lutibacter. However, several phenotypic characteristics, including hydrolysis of macromolecules, enzyme activities and carbon source oxidation, differentiated strain IMCC1507(T) from members of the genus. Data from this study indicate that strain IMCC1507(T) represents a novel species in the genus Lutibacter, for which the name Lutibacter flavus sp. nov. is proposed. The type strain is IMCC1507(T) ( = KACC 14312(T)  = NBRC 107589(T)).

Kordia periserrulae sp. nov., isolated from a marine polychaete Periserrula leucophryna, and emended description of the genus Kordia.

A Gram-negative, chemoheterotrophic, yellow-pigmented, non-motile, flexirubin-negative, facultatively anaerobic bacterium, designated strain IMCC1412(T), was isolated from a marine polychaete Periserrula leucophryna inhabiting a tidal flat of the Yellow Sea, Korea. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain IMCC1412(T) was most closely related to Kordia algicida, with a sequence similarity of 96.7 %, but only distantly related to other species in the family Flavobacteriaceae (<92 % similarity). The G+C content of the DNA was 37.3 mol%. The strain contained MK-6 as the major respiratory quinone and phosphatidylethanolamine, unidentified aminolipids and unidentified polar lipids as the major polar lipids. On the basis of phylogenetic distinctiveness and differential phenotypic characteristics, strain IMCC1412(T) ( = KACC 14311(T) = KCTC 22801(T) = NBRC 106077(T)) should be assigned to the genus Kordia as the type strain of a novel species, for which the name Kordia periserrulae sp. nov. is proposed. An emended description of the genus Kordia is also presented.

Genome sequence of strain IMCC3088, a proteorhodopsin-containing marine bacterium belonging to the OM60/NOR5 clade

Strain IMCC3088, cultivated from the Yellow Sea, is a novel isolate belonging to the OM60/NOR5 clade and is closely related to clone OM241, Congregibacter litoralis, and strain HTCC2080. Here, the genome sequence of strain IMCC3088 is presented, showing the absence of photosynthetic gene clusters and the presence of proteorhodopsin.

Complete Genome Sequence of Strain HTCC2170, a Novel Member of the Genus Maribacter in the Family Flavobacteriaceae

Strain HTCC2170 was isolated from surface waters off the Oregon coast using dilution-to-extinction culturing. Here, we present the finished genome sequence of a marine bacterium, Maribacter sp. strain HTCC2170. Strain sp. HTCC2170 is predicted to be a facultatively aerobic chemoorganotroph that, based on genomic sequence analysis, is capable of macromolecule degradation and anaerobic respiration.

Antarcticimonas flava gen. nov., sp. nov., isolated from Antarctic coastal seawater.

A marine bacterium, designated IMCC3175T, was isolated from a seawater sample collected off the Antarctic coast. The strain was Gram-negative, obligately aerobic, carotenoid pigment-containing, and rod-shaped bacterium that divided by binary fission. As determined by 16S rRNA gene sequence comparisons, the most closely related genera were Formosa (92.9∼93.3%), Bizionia (91.6∼93.2%), Gaetbulibacter (91.5∼92.8%), Sediminibacter (92.7%), Yeosuana (92.6%), Subsaximicrobium (92.1∼92.2%), and Gillisia (89.5∼92.2%). Phylogenese analysis based on 16S rRNA gene sequences showed that the strain formed a monophyletic clade together with the genera Sediminibacter and Subsaximicrobium but represented an independent phyletic line in this clade of the family Flavobacteriaceae. The DNA G+C content of the strain was 37.3 mol%. The major respiratory quinone was MK-6 and the predominant cellular fatty acids were C16:1 ω7c and/or iso-C15:0 2-OH (12.8%), anteiso-C15:0 (9.4%), and iso-C16:1 (9.4%). Low 16S rRNA gene sequence similarity, formation of a distinct phylogenetic branch, and several phenotypic characteristics, including a narrow range of temperature and salinity for growth, differentiated strain IMCC3175T from other related genera in the family Flavobacteriaceae. Therefore the name Antarcticimonas flava gen. nov., sp. nov. is proposed, with strain IMCC3175T (=KCCM 42713T =NBRC 103398T) as the type strain.

Lentisphaera marina sp. nov., and emended description of the genus Lentisphaera

Two Gram-stain-negative, non-motile, non-pigmented cocci, designated IMCC11369(T) and IMCC11389, were isolated from surface seawater of the East Sea of Korea by high-throughput cultivation based on dilution to extinction. Strains IMCC11369(T) and IMCC11389 shared 99.9 % 16S rRNA gene sequence similarity and >86.3 % DNA-DNA relatedness, which suggested that they belong to the same genomic species. The isolates were most closely related to Lentisphaera araneosa HTCC2155(T) (99.0 % 16S rRNA gene sequence similarity). Phylogenetic analysis revealed that the isolates formed a robust cluster with L. araneosa HTCC2155(T). DNA-DNA relatedness values, however, showed that the isolates were distantly related to L. araneosa HTCC2155(T) (2.0-18.6 %), which suggested that they represent a separate genomic species in the genus Lentisphaera. The two isolates were phenotypically differentiated from their closest relative by several characteristics, including degradation of macromolecules and carbon source utilization. The DNA G+C content was 44.5-45.2 mol% and the predominant cellular fatty acids were C14 : 0, C16 : 1ω9c and C16 : 0. Strain IMCC11369(T) contained MK-7 as the respiratory quinone and phosphatidylethanolamine and an unknown lipid as the major polar lipids. On the basis of data obtained in this study, a novel species is proposed to accommodate the isolates, Lentisphaera marina sp. nov. The type strain is IMCC11369(T) ( = KCTC 23780(T) = NBRC 108776(T)).

Genome Sequence of Strain IMCC14465, Isolated from the East Sea, Belonging to the PS1 Clade of Alphaproteobacteria

Strain IMCC14465 was isolated from surface seawater of the East Sea using dilution-to-extinction culturing. Phylogenetic analysis indicated that the strain belongs to the PS1 clade, which is closely related to the OCS116 clade in the Alphaproteobacteria. Here, we report the genome sequence of IMCC14465, the first isolate of the PS1 clade.

Characterization of spatial distribution of the bacterial community in the South Sea of Korea

In order to investigate the importance of spatial and environmental factors on the structure and diversity of bacterial communities, high-resolution 16S rRNA gene tag pyrosequencing was applied to bacterial communities in the littoral sea. Seawater samples were prepared from seven different stations in the South Sea of Korea, the marginal sea in the western Pacific Ocean, and were divided into three groups according to distances from the coastline. The majority of 19,860 sequences were affiliated with Alphaproteobacteria (58.2%), Gammaproteobacteria (7.9%), and Bacteroidetes (13.9%). The bacterioplankton community at each station was highly diverse and varied among the samples. Major bacterial lineages showed different niche preferences among three locational groups. Alphaproteobacteria was the most abundant bacterial class, and it harbored the most frequently recorded operational taxonomic units (OTUs) in all sampling stations. However, dominant groups at the order levels showed a clear difference among the samples. The SAR11 clade was more abundant in coastal waters while the Roseobacter clade prevailed at stations far away from the coastline. Furthermore, members of Actinobacteria and Cyanobacteria also exhibited spatial variability. The OM1 clade in Actinobacteria constituted a predominant fraction in coastal samples, but it was essentially absent at the distal stations closer to open ocean. In contrast, Synechococcus was the predominant taxon in the distal samples, accounting for 7.1–19.5%, but was hardly detected in coastal waters, representing less than 0.7%. In Bacteroidetes, NS5 and NS9 groups tended to inhabit coastal waters while the genera Polaribacter and Ulvibacter were more abundant in distal stations. Clustering analysis and principle coordinates analysis based on OTU data indicated that bacterial communities in the studied area were separated into three groups that coincided with locational grouping. Statistical analysis showed that phosphate and dissolved oxygen concentration had a significant influence on the bacterial community composition.

Blastococcus atacamensis sp. nov., a novel strain adapted to life in the Yungay core region of the Atacama Desert

A polyphasic study was undertaken to establish the taxonomic status of a Blastococcus strain isolated from an extreme hyper-arid Atacama Desert soil. The isolate, strain P6T, was found to have chemotaxonomic and morphological properties consistent with its classification in the genus Blastococcus. It was shown to form a well-supported branch in the Blastococcus 16S rRNA gene tree together with the type strains of Blastococcus capsensis and Blastococcus saxobsidens and was distinguished from the latter, its close phylogenetic neighbour, by a broad range of phenotypic properties. The draft genome sequence of isolate P6T showed 84.6 % average nucleotide identity, 83.0 % average amino acid identity and a digital DNA-DNA hybridisation value of 27.8 % in comparison with the genome sequence of B. saxobsidens DSM 44509T, values consistent with its assignment to a separate species. Based on these data it is proposed that isolate P6T (NCIMB 15090T=NRRL B-65468T) be assigned to the genus Blastococcus as Blastococcus atacamensis sp. nov. Analysis of the whole genome sequence of B. atacamensis P6T, with 3778 open reading frames and a genome size of 3.9 Mb showed the presence of genes and gene clusters that encode for properties that reflect its adaptation to the extreme environmental conditions that prevail in Atacama Desert soils.