Systemic multiomics evaluation of the therapeutic effect of Bacteroides species on liver cirrhosis in male mice.

IMPORTANCE: The human gut microbiome mediates bidirectional interaction within the gut-liver axis, while liver diseases, including liver cirrhosis, are very closely related to the state of the gut environment. Thus, improving the health of the gut-liver axis by targeting the intestinal microbiota is a potential therapeutic approach in hepatic diseases. This study examines changes in metabolomics and microbiome composition by treating bacteria derived from the human gut in mice with liver cirrhosis. Interorgan-based multiomics profiling coupled with functional examination demonstrated that the treatment of Bacteroides dorei pertained to protective effects on liver cirrhosis by normalizing the functional, metabolic, and metagenomic environment through the gut-liver axis. The study provides the potential value of a multiomics-based and interorgan-targeted evaluation platform for the comprehensive examination and mechanistic understanding of a wide range of biologics, including gut microbes. Furthermore, the current finding also suggests in-depth future research focusing on the discovery and validation of next-generation probiotics and products (postbiotics).

Metagenomic data from surface seawater of the east coast of South Korea.

The East Sea, also known as the Sea of Japan, is a marginal sea located in the western Pacific Ocean, displaying comparable characteristics to Earth's oceans, thereby meriting its recognition as a "miniature ocean". The East Sea exhibits a range of annually-recurring biogeochemical features in accordance with seasonal fluctuations, such as phytoplankton blooms during the spring and autumn seasons. Despite ongoing monitoring efforts focused on water quality and physicochemical parameters, the investigation of prokaryotic assemblages in the East Sea, encompassing seasonal variations, has been infrequently pursued. Here, we present a monthly time-series metagenomic dataset spanning a one-year period in 2009, obtained from surface (10 m) seawater samples collected off the coast of the East Sea. The dataset encompasses 12 metagenomes, amounting 195 Gbp, with 14.73-22.52 Gbp per sample. This dataset is accompanied by concurrently measured physicochemical parameters. Our anticipation is that these metagenomes will facilitate extensive investigations aimed at elucidating various aspects of the marine microbial ecosystems in the East Sea.

Lactobacillus lactis and Pediococcus pentosaceus-driven reprogramming of gut microbiome and metabolome ameliorates the progression of non-alcoholic fatty liver disease.

BACKGROUND: Although microbioa-based therapies have shown putative effects on the treatment of non-alcoholic fatty liver disease (NAFLD), it is not clear how microbiota-derived metabolites contribute to the prevention of NAFLD. We explored the metabolomic signature of Lactobacillus lactis and Pediococcus pentosaceus in NAFLD mice and its association in NAFLD patients. METHODS: We used Western diet-induced NAFLD mice, and L. lactis and P. pentosaceus were administered to animals in the drinking water at a concentration of 109 CFU/g for 8 weeks. NAFLD severity was determined based on liver/body weight, pathology and biochemistry markers. Caecal samples were collected for the metagenomics by 16S rRNA sequencing. Metabolite profiles were obtained from caecum, liver and serum. Human stool samples (healthy control [n = 22] and NAFLD patients [n = 23]) were collected to investigate clinical reproducibility for microbiota-derived metabolites signature and metabolomics biomarker. RESULTS: L. lactis and P. pentosaceus supplementation effectively normalized weight ratio, NAFLD activity score, biochemical markers, cytokines and gut-tight junction. While faecal microbiota varied according to the different treatments, key metabolic features including short chain fatty acids (SCFAs), bile acids (BAs) and tryptophan metabolites were analogously restored by both probiotic supplementations. The protective effects of indole compounds were validated with in vitro and in vivo models, including anti-inflammatory effects. The metabolomic signatures were replicated in NAFLD patients, accompanied by the comparable levels of Firmicutes/Bacteroidetes ratio, which was significantly higher (4.3) compared with control (0.6). Besides, the consequent biomarker panel with six stool metabolites (indole, BAs, and SCFAs) showed 0.922 (area under the curve) in the diagnosis of NAFLD. CONCLUSIONS: NAFLD progression was robustly associated with metabolic dys-regulations in the SCFAs, bile acid and indole compounds, and NAFLD can be accurately diagnosed using the metabolites. L. lactis and P. pentosaceus ameliorate NAFLD progression by modulating gut metagenomic and metabolic environment, particularly tryptophan pathway, of the gut-liver axis.

Characteristics of the Gut Microbiome of Healthy Young Male Soldiers in South Korea: The Effects of Smoking.

BACKGROUND/AIMS: South Korean soldiers are exposed to similar environmental factors. In this study, we sought to evaluate the gut microbiome of healthy young male soldiers (HYMS) and to identify the primary factors influencing the microbiome composition. METHODS: We prospectively collected stool from 100 HYMS and performed next-generation sequencing of the 16S rRNA genes of fecal bacteria. Clinical data, including data relating to the diet, smoking, drinking, and exercise, were collected. RESULTS: The relative abundances of the bacterial phyla Firmicutes, Actinobacteria, Bacteroidetes, and Proteobacteria were 72.3%, 14.5%, 8.9%, and 4.0%, respectively. Fifteen species, most of which belonged to Firmicutes (87%), were detected in all examined subjects. Using cluster analysis, we found that the subjects could be divided into the two enterotypes based on the gut microbiome bacterial composition. Compared with enterotype 2 subjects, subjects classified as enterotype 1 tended to be characterized by higher frequencies of potentially harmful lifestyle habits (current smoker: 55.6% vs 36.6%, p=0.222; heavy drinker: 16.7% vs 3.7%, p=0.120; insufficient physical activity: 27.8% vs 14.6%, p=0.318). We identified a significant difference in the microbiome compositions of current and noncurrent smokers (p=0.008); the former differed from the latter mainly in a relatively lower abundance of Bifidobacterium species and a higher abundance of Negativicutes. CONCLUSIONS: A high abundance of Actinobacteria and low abundance of Bacteroidetes were the main features distinguishing the gut microbiomes of HYMS, and current smokers could be differentiated from noncurrent smokers by their lower abundance of Bifidobacterium and higher abundance of Negativicutes.

Blautia faecicola sp. nov., isolated from faeces from a healthy human.

An obligately anaerobic, Gram-stain-positive, non-motile and coccoid- or oval-shaped bacterium, designated strain KGMB01111T, was isolated from faeces from a healthy Korean. Comparative analysis of 16S rRNA gene sequences indicated that KGMB01111T was closely related to Ruminococcus gauveauii CCRI-16110T (93.9 %) and Blautia stercoris GAM6-1T (93.7 %), followed by Clostridium nexile DSM 1787T (93.5 %), Blautia producta ATCC 27340T (93.4 %), Blautia hydrogenotrophica DSM 10507T (93.1 %) and Blautia coccoides ATCC 29236T (93.1 %) within the family Lachnospiraceae (Clostridium rRNA cluster XIVa). Phylogenetic analysis based on the 16S rRNA gene sequences indicated that KGMB01111T formed a separate branch with species in the genus Blautia. The major cellular fatty acids (>10.0 %) were C16 : 0 and C18 : 1 cis 9 dimethyl acetal (DMA), and the major polar lipids were aminophospholipids and lipids. KGMB01111T contained meso-diaminopimelic acid in cell-wall peptidoglycan. The predominant end product of fermentation produced by KGMB01111T was acetic acid. Based on the whole-genome sequence, the DNA G+C content of the isolate was 44.7 mol%. On the basis of the phenotypic, chemotaxonomic and phylogenetic characteristics, KGMB01111T represents a novel species within the genus Blautia for which the name Blautia faecicola sp. nov. is proposed. The type strain is KGMB01111T (=KCTC 15706T=DSM 107827T).

Bacteroides faecalis sp. nov., isolated from human faeces.

A novel Gram-stain-negative and strictly anaerobic bacterial strain, designated KGMB02408T, was isolated from faeces of a healthy human in the Republic of Korea. The isolate was characterized as non-motile, non-spore-forming and rod-shaped (variable in length). The results of phylogenetic analysis based on 16S rRNA gene sequences revealed that strain KGMB02408T belonged to the genus Bacteroides and was most closely related to Bacteroides faecichinchillae JCM 17102T (=KCTC 15666T; 96.5 %). Based on its whole-genome sequence, the DNA G+C content of the isolate was 39.5 mol%. The average nucleotide identity value between strain KGMB02408T and related species, B. faecichinchillae JCM 17102T, was 93.8 %. The major cellular fatty acids (>10 %) of the isolate were anteiso-C15 : 0, iso-C17 : 0-OH, summed feature 11 (iso-C17 : 0-OH and/or C18 : 2 DMA) and C16 : 0. Menaquinone-8 (28.6 %) and menaquinone-10 (47.1 %) were detected as the major respiratory quinones in the isolate. The major end products of glucose fermentation produced by strain KGMB02408T were lactic acid, acetic acid and formic acid. Based on its phylogenetic, phenotypic and chemotaxonomic characteristics, strain KGMB02408T represents a novel species of the genus Bacteroides in the family Bacteroidaceae. The type strain is KGMB02408T (=KCTC 15687T=DSM 107828T).

Comparative Genomic Analysis of the 2016 Vibrio cholerae Outbreak in South Korea.

In August 2016, South Korea experienced a cholera outbreak that caused acute watery diarrhea in three patients. This outbreak was the first time in 15 years that an outbreak was not linked to an overseas source. To identify the cause and to study the epidemiological implications of this outbreak, we sequenced the whole genome of Vibrio cholerae isolates; three from each patient and one from a seawater sample. Herein we present comparative genomic data which reveals that the genome sequences of these four isolates are very similar. Interestingly, these isolates form a monophyletic clade with V. cholerae strains that caused an outbreak in the Philippines in 2011. The V. cholerae strains responsible for the Korean and Philippines outbreaks have almost identical genomes in which two unique genomic islands are shared, and they both lack SXT elements. Furthermore, we confirm that seawater is the likely source of this outbreak, which suggests the necessity for future routine surveillance of South Korea's seashore.

Application of the Whole Genome-Based Bacterial Identification System, TrueBac ID, Using Clinical Isolates That Were Not Identified With Three Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS) Systems.

BACKGROUND: Next-generation sequencing is increasingly used for taxonomic identification of pathogenic bacterial isolates. We evaluated the performance of a newly introduced whole genome-based bacterial identification system, TrueBac ID (ChunLab Inc., Seoul, Korea), using clinical isolates that were not identified by three matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) systems and 16S rRNA gene sequencing. METHODS: Thirty-six bacterial isolates were selected from a university-affiliated hospital and a commercial clinical laboratory. Species was identified by three MALDI-TOF MS systems: Bruker Biotyper MS (Bruker Daltonics, Billerica, MA, USA), VITEK MS (bioMérieux, Marcy l'Étoile, France), and ASTA MicroIDSys (ASTA Inc., Suwon, Korea). Whole genome sequencing was conducted using the Illumina MiSeq system (Illumina, San Diego, CA, USA), and genome-based identification was performed using the TrueBac ID cloud system (www.truebacid.com). RESULTS: TrueBac ID assigned 94% (34/36) of the isolates to known (N=25) or novel (N=4) species, genomospecies (N=3), or species group (N=2). The remaining two were identified at the genus level. CONCLUSIONS: TrueBac ID successfully identified the majority of isolates that MALDI-TOF MS failed to identify. Genome-based identification can be a useful tool in clinical laboratories, with its superior accuracy and database-driven operations.

Olsenella faecalis sp. nov., an anaerobic actinobacterium isolated from human faeces.

A novel actinobacterial strain, designated KGMB04489T, was isolated from the faeces of a healthy Korean. Cells of the strain were strictly anaerobic, Gram-stain-positive and short-rod-shaped. On the basis of 16S rRNA gene sequence similarity, strain KGMB04489T belonged to the genus Olsenella and was most closely related to Olsenella scatoligenes SK9K4T (94.3 %), Olsenella uli ATCC 49627T (93.5 %), Olsenella umbonata lac31T (93.4 %) and Olsenella profusa D315A-29T (93.3 %). The major end product was lactic acid. The DNA G+C content was 65.5 mol%. The major cellular fatty acids of strain KGMB04489T were C18 : 1cis9, C18 : 1cis9 DMA and C16 : 0. Strain KGMB04489T contained meso-diaminopimelic acid as the diamino acid in the peptidoglycan. The polar lipids consisted of an unidentified phospholipid, six unidentified glycolipids and an unidentified lipid. Based on phylogenetic, physiological and chemotaxonomic characteristics, strain KGMB04489T is considered to represent a novel species within the genus Olsenella, for which the name Olsenellafaecalis sp. nov. is proposed. The type strain is KGMB04489T (=KCTC 15699T=CCUG 72345T).

Genomic characterization of Nocardia seriolae strains isolated from diseased fish.

Members of the genus Nocardia are widespread in diverse environments; a wide range of Nocardia species are known to cause nocardiosis in several animals, including cat, dog, fish, and humans. Of the pathogenic Nocardia species, N. seriolae is known to cause disease in cultured fish, resulting in major economic loss. We isolated two N. seriolae strains, CK-14008 and EM15050, from diseased fish and sequenced their genomes using the PacBio sequencing platform. To identify their genomic features, we compared their genomes with those of other Nocardia species. Phylogenetic analysis showed that N. seriolae shares a common ancestor with a putative human pathogenic Nocardia species. Moreover, N. seriolae strains were phylogenetically divided into four clusters according to host fish families. Through genome comparison, we observed that the putative pathogenic Nocardia strains had additional genes for iron acquisition. Dozens of antibiotic resistance genes were detected in the genomes of N. seriolae strains; most of the antibiotics were involved in the inhibition of the biosynthesis of proteins or cell walls. Our results demonstrated the virulence features and antibiotic resistance of fish pathogenic N. seriolae strains at the genomic level. These results may be useful to develop strategies for the prevention of fish nocardiosis.

Mediterraneibacter butyricigenes sp. nov., a butyrate-producing bacterium isolated from human faeces.

A Gram-stain-positive, obligately anaerobic, non-motile, nonspore-forming, and rod-shaped bacterial strain, designated KGMB01110T, was isolated from a faecal sample of a healthy male in South Korea. Phylogenetic analysis based on 16S rRNA gene showed that strain KGMB01110T belonged to Clostridium cluster XIVa and was most closely related to Mediterraneibacter glycyrrhizinilyticus KCTC 5760T (95.9% 16S rRNA gene sequence similarity). The DNA G + C content of strain KGMB01110T based on its whole genome sequence was 44.1 mol%. The major cellular fatty acids (> 10%) of the isolate were C14:0 and C16:0. The strain KGMB01110T was positive for arginine dihydrolase, ß-galactosidase-6-phosphatase, and alkaline phosphatase. The strain KGMB01110T also produced acid from D-glucose and D-rhamnose, and hydrolyzed gelatin and aesculin. Furthermore, HPLC analysis and UV-tests of culture supernatant revealed that the strain KGMB01110T produced butyrate as the major end product of glucose fermentation. Based on the phylogenetic and phenotypic characteristics, strain KGMB01110T represent a novel species of the genus Mediterraneibacter in the family Lachnospiraceae. The type strain is KGMB01110T (= KCTC 15684T = CCUG 72830T).

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.

Rejection of reclassification of Lactobacillus kimchii and Lactobacillus bobalius as later subjective synonyms of Lactobacillus paralimentarius using comparative genomics.

Lactobacillus bobalius, Lactobacillus kimchii and Lactobacillus paralimentarius belong to the genus Lactobacillus and show close phylogenetic relationships. In a previous study, L. bobalius and L. kimchii were proposed to be reclassified as later heterotypic synonyms of L. paralimentarius using high 16S rRNA gene sequence similarities (≥99.5 %) and DNA-DNA hybridization values (≥82 %). We determined high quality whole genome assemblies of the type strains of L. bobalius and L. kimchii, which were then compared with that of L. paralimentarius. Average nucleotide identity values among three genomes ranged from 91.4 to 92.3 % which are clearly below 95~96 %, the generally recognized cutoff value for bacterial species boundaries. On the basis of comparative genomic evidence, L. bobalius, L. kimchii, and L. paralimentarius should stand as separate species in the genus Lactobacillus. We therefore suggest rejecting the previous proposal to combine these three species into a single species.

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.

Expansion of Cultured Bacterial Diversity by Large-Scale Dilution-to-Extinction Culturing from a Single Seawater Sample.

High-throughput cultivation (HTC) based on a dilution-to-extinction method has been applied broadly to the cultivation of marine bacterial groups, which has often led to the repeated isolation of abundant lineages such as SAR11 and oligotrophic marine gammaproteobacteria (OMG). In this study, to expand the phylogenetic diversity of HTC isolates, we performed a large-scale HTC with a single surface seawater sample collected from the East Sea, the Western Pacific Ocean. Phylogenetic analyses of the 16S rRNA genes from 847 putative pure cultures demonstrated that some isolates were affiliated with not-yet-cultured clades, including the OPB35 and Puniceicoccaceae marine group of Verrucomicrobia and PS1 of Alphaproteobacteria. In addition, numerous strains were obtained from abundant clades, such as SAR11, marine Roseobacter clade, OMG (e.g., SAR92 and OM60), OM43, and SAR116, thereby increasing the size of available culture resources for representative marine bacterial groups. Comparison between the composition of HTC isolates and the bacterial community structure of the seawater sample used for HTC showed that diverse marine bacterial groups exhibited various growth capabilities under our HTC conditions. The growth response of many bacterial groups, however, was clearly different from that observed with conventional plating methods, as exemplified by numerous isolates of the SAR11 clade and Verrucomicrobia. This study showed that a large number of novel bacterial strains could be obtained by an extensive HTC from even a small number of samples.

Complete genome sequence of bacteriophage P8625, the first lytic phage that infects Verrucomicrobia.

Bacteriophage P8625 is a lytic bacteriophage that infects the verrucomicrobial strain IMCC8625, a marine bacterium affiliated with Verrucomicrobia subdivision 4. Both the bacteriophage and the host bacterial strain were isolated from surface seawater samples collected off the east coast of Korea. The phage particle has an icosahedral capsid with a diameter of ~47 nm and a long tail of ~75 nm in length, showing the distinctive morphology of the Siphoviridae family. The complete genome sequence of phage P8625 is 32,894 bp long with 51.0 % G + C content. This is the first report of the complete genome sequence of a lytic phage that infects the Verrucomicrobia, for which the name "verrucophage" is proposed.

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)).

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.

Genome sequence of "Candidatus Aquiluna" sp. strain IMCC13023, a marine member of the Actinobacteria isolated from an arctic fjord.

We report the genome sequence of actinobacterial strain IMCC13023, isolated from arctic fjord seawater. Phylogenetic analysis of 16S rRNA gene showed that the strain is related to "Candidatus Aquiluna rubra." The genome information suggests that strain IMCC13023 is a photoheterotroph carrying actinorhodopsin, with the smallest genome ever reported for a free-living member of the Actinobacteria.