Peptostreptococcus equinus sp. nov., isolated from horse faeces.

A Gram-stain-positive, non-spore-forming, and obligate anaerobic bacteria designated strain CBA3647T was isolated from a horse faecal sample in Jeju, Republic of Korea. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain CBA3647T formed a distinct phyletic lineage from closely related species within the genus Peptostreptococcus. Based on comparative analysis of 16S rRNA gene sequences, Peptostreptococcus anaerobius ATCC 27337T is most closely related to strain CBA3647T with a 16S rRNA gene similarity of 98.31 %, while similarity to other type strains is below 98.0 %. The genomic DNA G+C content of strain CBA3647T was 30.0 mol%. The digital DNA-DNA hybridization values between strain CBA3647T and the six Peptostreptococcus species were equal to or less than 24 %. Cells were non-motile and oval-shaped cocci with catalase-positive and oxidase-negative activities. Growth occurred at 20-40 °C (optimum, 35 °C), pH 6-8 (optimum, pH 7), and in the presence of 0-2 % (w/v) NaCl (optimum, 1 %). Strain CBA3647T contained C14 : 0 iso and C16 : 0 as major fatty acids. Phenotypic, chemotaxonomic, and molecular properties of strain CBA3647T suggest that it represents a novel species in the genus Peptostreptococcus, which has been named Peptostreptococcus equinus sp. nov. The type strain is CBA3647T (=KACC 22891T= JCM 35846T).

Cutibacterium equinum sp. nov., isolated from horse faeces.

Strain CBA3108T is a Gram-positive, non-spore-forming, obligately anaerobic bacterium isolated from horse faecal samples obtained in Jeju Island, Republic of Korea. The cells of CBA3108T are non-motile short rods that have been assessed as catalase-positive and oxidase-negative. Growth of the strain occurs under the following conditions: 25-45 °C (optimum, 35 °C); pH 6-9 (optimum, pH 6); and in the presence of 0-6 % (w/v) NaCl (optimum, 2%). Major fatty acids in the strain include C15 : 0 iso and C15 : 0 iso DMA, while major polar lipids include phosphatidylglycerol, diphosphatidylglycerol and phosphatidylcholine. Based on phylogenetic analysis using 16S rRNA gene sequences, strain CBA3108T forms a phyletic lineage distinct from other closely related species within the genus Cutibacterium. It was found to be most closely related to Cutibacterium avidum ATCC 25577T (98.27 % 16S rRNA gene sequence similarity) and other strains within the genus (≤98.0 %). The genomic DNA G+C content of strain CBA3108T was 63.2 mol%. The in silico DNA-DNA hybridization values of strain CBA3108T with C. avidum ATCC 25577T, C. porci WCA-380-WT-3AT and C. acnes subsp. acnes DSM 1897T were 33.6, 21.7 and 22.7 %, respectively. Its phenotypic, chemotaxonomic and molecular properties support the hypothesis that strain CBA3108T represents a novel species in the genus Cutibacterium, for which we propose the name Cutibacterium equinum sp. nov. The type strain is CBA3108T (=KACC 22889T=JCM 35966T).

Peptoniphilus equinus sp. nov., a novel Gram-stain-positive anaerobic coccus isolated from the faeces of a thoroughbred racehorse.

A novel, anaerobic, Gram-stain-positive coccoid strain, CBA3646T, was isolated from the faeces of a thoroughbred racehorse. Phylogenetic analysis based on 16S rRNA gene sequencing yielded results indicative of CBA3646T representing a member of the genus Peptoniphilus, with the species most closely related to it being Peptoniphilus asaccharolyticus DSM 20463T, with a similarity of 94.79 %. DNA-DNA relatedness and average nucleotide identity values between CBA3646T and P. asaccharolyticus DSM 20463T were 21.4 and 67.6 %, respectively. CBA3646T has a circular chromosomal genome of 1 709 189 bp (45.5 mol% DNA G+C content), containing 1652 genes in total, 1584 predicted protein-coding genes, 3 complete rRNA loci and 47 tRNA genes. The cells were non-motile diplococci, catalase-positive and oxidase-negative. Growth of CBA3646T was observed at 20-40 °C (optimal temperature, 35 °C) and in the presence of 0-4 % (w/v) NaCl (optimum concentration, 1 %). The major fatty acids (>10 %) of CBA3646T were C16 : 0, C18 : 1ω9c and C18 : 1ω9c dimethyl acetal, with its major polar lipids being diphosphatidylglycerol and phosphatidylglycerol. The elucidated phylogenetic, physiological, chemotaxonomic and molecular properties are indicative of strain CBA3646T representing a novel species of the genus Peptoniphilus, or which the name Peptoniphilus equinus sp. nov. is proposed. The type strain is CBA3646T (= KACC 22890T = JCM 35845T).

6-Bromo-2-naphthol from Silene armeria extract sensitizes Acinetobacter baumannii strains to polymyxin.

The overuse of antibiotics has led to the emergence of multidrug-resistant bacteria, which are resistant to various antibiotics. Combination therapies using natural compounds with antibiotics have been found to have synergistic effects against several pathogens. Synergistic natural compounds can potentiate the effects of polymyxins for the treatment of Acinetobacter baumannii infection. Out of 120 types of plant extracts, only Silene armeria extract (SAE) showed a synergistic effect with polymyxin B (PMB) in our fractional inhibitory concentration and time-kill analyses. The survival rate of G. mellonella infected with A. baumannii ATCC 17978 increased following the synergistic treatment. Interestingly, the addition of osmolytes, such as trehalose, canceled the synergistic effect of SAE with PMB; however, the underlying mechanism remains unclear. Quadrupole time-of-flight liquid chromatography-mass spectrometry revealed 6-bromo-2-naphthol (6B2N) to be a major active compound that exhibited synergistic effects with PMB. Pretreatment with 6B2N made A. baumannii cells more susceptible to PMB exposure in a time- and concentration-dependent manner, indicating that 6B2N exhibits consequential synergistic action with PMB. Moreover, the exposure of 6B2N-treated cells to PMB led to higher membrane leakage and permeability. The present findings provide a promising approach for utilizing plant extracts as adjuvants to reduce the toxicity of PMB in A. baumannii infection.

Massilia soli sp. nov., isolated from soil.

A Gram-stain-negative, catalase- and oxidase-positive and aerobic bacterium, designated strain R798T, was isolated from soil in South Korea. Cells were motile rods by means of a single polar flagellum. Growth of strain R798T was observed at 15-35 °C (optimum, 25-30 °C), pH 5.0-8.0 (optimum, 6.0) and 0-1.5 % NaCl (optimum, 0.3 %). Strain R798T contained ubiquinone-8 as the sole isoprenoid quinone, summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c) and C16 : 0 as the major fatty acids and phosphatidylglycerol and phosphatidylethanolamine as the major polar lipids. The DNA G+C content of strain R798T calculated from the whole genome sequence was 63.3 mol%. Phylogenetic analyses based on the 16S rRNA gene and whole genome sequences revealed that strain R798T formed a distinct phyletic lineage within the genus Massilia. Strain R798T was most closely related to Massilia eurypsychrophila B528-3T with a 98.0 % 16S rRNA gene sequence similarity. Average nucleotide identity and digital DNA-DNA hybridization values between strain R798T and the type strain of M. eurypsychrophila were 79.2 and 22.7 %, respectively. Based on the phenotypic, chemotaxonomic and molecular analyses, strain R798T represents a novel species of the genus Massilia, for which the name Massilia soli sp. nov. is proposed. The type strain is R798T (=KACC 22114T=JCM 34601T).

Ramlibacter algicola sp. nov., isolated from a freshwater alga Cryptomonas obovoidea.

A Gram-stain-negative, strictly aerobic, catalase-negative, oxidase-positive and non-motile rod-shaped bacterium, designated strain CrO1T, was isolated from a freshwater alga Cryptomonas obovoidea in the Nakdong river of South Korea. Colonies of CrO1T were white, convex and circular and growth was observed at 25-40 °C (optimum, 37 °C) and pH 6.0-9.0 (optimum, pH 7) and in the presence of 0-0.5 % (w/v) NaCl (optimum, 0 %). CrO1T contained C16 : 0, summed feature 5 (comprising C18 : 0ante and/or C18 : 2ω6,9c), C18 : 0, summed feature 3 (comprising C16 : 1ω7c and/or C16 : 1ω6c) and summed feature 8 (comprising C18 : 1ω7c and/or C18 : 1ω6c) as the major cellular fatty acids (>5 %) and ubiquinone-8 as the sole respiratory quinone. Phosphatidylethanolamine was detected as the major polar lipid. The DNA G+C content of CrO1T, calculated from the whole genome sequence was 69.6 mol%. CrO1T was most closely related to Ramlibacter humi 18x22-1T with a 97.6 % 16S rRNA sequence similarity and shared less than 97.4 % 16S rRNA sequence similarities with other type strains. Phylogenetic analyses based on the 16S rRNA gene and whole genome sequences revealed that CrO1T formed a distinct phyletic lineage within the genus Ramlibacter. On the basis of the results of phenotypic, chemotaxonomic and molecular analysis, CrO1T clearly represents a novel species of the genus Ramlibacter, for which the name Ramlibacter algicola sp. nov. is proposed. The type strain is CrO1T (=KACC 19926T=JCM 33302T).

Safety Assessment of Lactiplantibacillus (formerly Lactobacillus) plantarum Q180.

The safety of the probiotic strain Q180, which exerts postprandial lipid-lowering effects, was bioinformatically and phenotypically evaluated. The genome of strain Q180 was completely sequenced, and single circular chromosome of 3,197,263 bp without any plasmid was generated. Phylogenetic and related analyses using16S rRNA gene and whole-genome sequences revealed that strain Q180 is a member of Lactiplantibacillus (Lp., formerly Lactobacillus) plantarum. Antimicrobial resistance (AMR) genes were bioinformatically analyzed using all Lp. plantarum genomes available in GenBank, which showed that AMR genes are present differently depending on Lp. plantarum strains. Bioinformatic analysis demonstrated that some mobile genetic elements such as prophages and insertion sequences were identified in the genome of strain Q180, but because they did not contain harmful genes such as AMR genes and virulence factor (VF)- and toxin-related genes, it was suggested that there is no transferability of harmful genes. The minimum inhibition concentrations of seven tested antibiotics suggested by the European Food Safety Authority guidelines were slightly lower than or equal to the microbiological cut-off values for Lp. plantarum. Strain Q180 did not show hemolytic and gelatinase activities and biogenic amine-producing ability. Taken together, this study demonstrated the safety of strain Q180 in terms of absence of AMR genes and VF- and toxin-related genes as a probiotic strain.

Flavobacterium solisilvae sp. nov. and Flavobacterium silvaticum sp. nov., isolated from forest soil.

Two Gram-stain-negative, yellow-pigmented and strictly aerobic bacteria, designated strains SE-s27T and SE-s28T, were isolated from forest soil. Both strains were non-motile rods that were catalase-positive and oxidase-negative and grew optimally at 25-30 °C, pH 8.0 and with 0 % (w/v) NaCl. Strain SE-s28T produced flexirubin-type pigments, but strain SE-s27T did not produce them. Both strains contained menaquinone-6 as the sole respiratory quinone and phosphatidylethanolamine as a major polar lipid. As the major cellular fatty acids (>10 %), SE-s27T contained iso-C15 : 1 and iso-C15 : 1G, whereas SE-s28T contained iso-C15 : 0 and summed feature 3 comprising C16 : 1ω7c and/or C16 : 1ω6c and/or iso-C15 : 0 2-OH. The DNA G+C contents of strains SE-s27T and SE-s28T were 33.1 and 44.3 mol%, respectively. The results of phylogenetic analysis based on 16S rRNA gene sequences revealed that SE-s27T and SE-s28T formed respective distinct phylogenetic lineages within the genus Flavobacterium. Strains SE-s27T and SE-s28T were most closely related to Flavobacterium macrobrachii an-8T and Flavobacterium piscinae ICH-30T with 98.0 and 94.5 % 16S rRNA gene sequence similarities, respectively. In conclusion, strains SE-s27T and SE-s28T represent novel species of the genus Flavobacterium, for which the names Flavobacterium solisilvae sp. nov. and Flavobacterium silvaticum sp. nov. are proposed. The type strains of F. solisilvae and F. silvaticum are SE-s27T (=KACC 18802T=JCM 31544T) and SE-s28T (=KACC 18803T=JCM 31545T), respectively.

Ramlibacter terrae sp. nov. and Ramlibacter montanisoli sp. nov., Isolated from Soil.

Two gram-negative, catalase-positive, strictly aerobic, and white colony-forming bacteria, strains H242T and B156T, were isolated from soil in South Korea. Cells of strain H242T were oxidase-positive and non-motile short rods, while those of strain B156T were oxidase-negative and long non-motile rods. Ubiquinone-8 was identified as the sole isoprenoid quinone in both strains. C16:0, cyclo-C17:0, and summed feature 3 (C16:1 ω7c and/or C16:1 ω6c) and phosphatidylethanolamine, phosphatidylglycerol, and diphosphatidylglycerol were identified in both strains as the major cellular fatty acids and polar lipids, respectively. The DNA G+C contents of strains H242T and B156T were 69.4 mol% and 69.3 mol%, respectively. Phylogenetic analyses based on 16S rRNA and 92 concatenated core gene sequences revealed that strains H242T and B156T formed distinct phylogenic lineages from other Ramlibacter type strains. The DNA-DNA hybridization (DDH) value between strains H242T and B156T was 24.6%. Strains H242T and B156T were most closely related to Ramlibacter ginsenosidimutans BXN5-27T and Ramlibacter monticola G-3-2T with 98.4% and 98.6% 16S rRNA gene sequence similarities, respectively. Digital DDH values between strain H242T and R. ginsenosidimutans and between strain B156T and R. monticola were 23.5% and 26.1%, respectively. Phenotypic, chemotaxonomic, and molecular analyses indicated that strains H242T and B156T represent two novel species of the genus Ramlibacter, for which the names Ramlibacter terrae sp. nov. and Ramlibacter montanisoli sp. nov., respectively, are proposed. The type strains of R. terrae and R. montanisoli are H242T (=KACC 21667 T =JCM 33922T) and B156T (=KACC 21665 T =JCM 33920T), respectively.

Maritimibacter harenae sp. nov. and Sneathiella litorea sp. nov.: members of Alphaproteobacteria isolated from sea sand.

Two Gram-negative, rod bacteria, strains DP07T and DP05T, showing catalase- and oxidase-positive activities, were isolated from sea sand in South Korea. Strain DP07T was strictly aerobic and had a yellow colony colour. Contrastingly, strain DP05T was facultatively aerobic and had a creamy colony colour. Both strains contained ubiquinone-10 as the sole isoprenoid quinone. Strain DP07T contained cyclo-C19:0 ω8c, C16:0, summed feature 8 (comprising C18:1 ω7c and/or C18:1 ω6c), and C16:0 2-OH as the major fatty acids and phosphatidylglycerol, phosphatidylethanolamine, an unidentified phospholipid, and an unidentified polar lipid as the major polar lipids. Strain DP05T contained C16:0, cyclo-C19:0, and summed feature 8 (comprising C18:1 ω7c and/or C18:1 ω6c) as the major fatty acids and phosphatidylglycerol, phosphatidylethanolamine, an unidentified aminophospholipid, and two unidentified polar lipids as the major polar lipids. Cadaverine was detected as the predominant polyamine in both strains. The DNA G + C contents of strains DP07T and DP05T were 66.1 mol% and 51.8 mol%, respectively. Phylogenetic analysis based on 16S rRNA gene sequences showed that strains DP07T and DP05T formed close phylogenetic lineages with Maritimibacter alkaliphilus HTCC2654T (similarity, 98.1%) and Sneathiella chungangensis CAU 1294 T (similarity, 98.5%), respectively. The average nucleotide identity and DNA-DNA hybridisation values between strain DP07T and M. alkaliphilus were 80.0% and 23.0%, respectively, and those between strain DP05T and S. chungangensis were 77.1% and 19.9%, respectively. Based on the results of phenotypic, chemotaxonomic, and molecular analyses, strains DP07T and DP05T represent two novel species of the genera Maritimibacter and Sneathiella, respectively, for which we propose the following names: Maritimibacter harenae sp. nov. and Sneathiella litorea sp. nov. The type strains of M. harenae and S. litorea were DP07T (= KACC 21429 T = JCM 33811 T) and DP05T (= KACC 21431 T = JCM 33810 T), respectively.

Paenibacillus silvestris sp. nov., Isolated from Forest Soil.

A bacterial strain, designated 5J-6T, was isolated from soil in Cheongnyeongpo, Republic of Korea. Cells were Gram-stain-positive, strictly aerobic, and motile rods and their catalase and oxidase activities were positive. Strain 5J-6T grew at 10-30 °C, pH 6.0-9.0, and 0-0.8% (w/v) NaCl concentration, with optimum growth at 25 °C, pH 6.5, and 0.4% NaCl concentration. Anteiso-C15:0 and iso-C16:0 were detected as the predominant fatty acids and menaquinone-7 was the sole isoprenoid quinone detected. Strain 5J-6T contained phosphatidylethanolamine, phosphatidylglycerol and an unidentified phospholipid as major polar lipids. The peptidoglycan belonged to the type A1γ meso-diaminopimelic acid. The G+C content of the genomic DNA calculated from the whole genomic sequence was 46.1 mol%. Phylogenetic analysis of strain 5J-6T based on 16S rRNA gene sequences placed the isolate into a member of the genus Paenibacillus. Sequence similarity analysis of 16S rRNA gene sequences revealed that strain 5J-6T was most closely related to Paenibacillus aceris KUDC4121T and Paenibacillus chondroitinus DSM 5051T with 98.76% and 98.42% similarities, respectively. Average nucleotide identity and in silico DNA-DNA hybridization values between strain 5J-6T and the type strain of P. aceris were 83.97% and 28.60%, respectively. Based on the phylogenetic and phenotypic characteristics and genomic data, strain 5J-6T could be considered to represent a novel species of the genus Paenibacillus, for which the name Paenibacillus silvestris sp. nov. is proposed. The type strain is 5J-6T (= KACC 21430T = JCM 33812T).

Nonlabens ponticola sp. nov., isolated from seawater and reclassification of Nonlabens sediminis as a later heterotypic synonym of Nonlabens tegetincola.

A Gram-stain-negative, orange-pigmented and strictly aerobic bacterium, designated strain MJ115T, was isolated from seawater in Pohang, South Korea. Cells were non-motile rods and showed positive reactions for catalase and oxidase tests. Growth of strain MJ115T was observed at 4-35 °C (optimum, 30 °C), pH 6.0-7.0 (optimum, pH 6.5) and in the presence of 0-8.0 % (w/v) NaCl (optimum, 2.0%). Strain MJ115T contained iso-C15 : 0, anteiso-C15 : 0, anteiso-C17 : 1 ω9c, C17 : 0 2-OH, iso-C16 : 0 3-OH, iso-C17 : 0 3-OH and summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c) as major cellular fatty acids and menaquinone-6 as the major respiratory quinone. Phosphatidylethanolamine, two unidentified aminolipids and four unidentified lipids were detected as major polar lipids. The G+C content of the genomic DNA was 40.7 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain MJ115T formed a phyletic lineage with Nonlabens marinus S1-08T, Nonlabens agnitus JC2678T and Nonlabens antarcticus AKS 622T within the genus Nonlabens. Strain MJ115T was also most closely related to N. marinus S1-08T, N. agnitus JC2678T and N. antarcticus AKS 622T with 96.5, 96.4 and 96.0 % 16S rRNA sequence similarities, respectively. Here it is proposed that strain MJ115T represents a new species of the genus Nonlabens, for which the name Nonlabens ponticola sp. nov. is proposed. The type strain is MJ115T (=KCTC 72237T=NBRC 113963T). In addition, the comparison of the whole genome sequences and phenotypic features suggested that Nonlabens tegetincola and Nonlabens sediminis belong to the same species. Therefore, it is proposed that N. sediminis is reclassified as a later heterotypic synonym of N. tegetincola.

Aestuariirhabdus litorea gen. nov., sp. nov., isolated from a sea tidal flat and proposal of Aestuariirhabdaceae fam. nov.

A Gram-negative, moderately halophilic and facultatively aerobic bacterium, designated strain GTF13T, was isolated from a sea tidal flat. Cells were curved rods and motile by a single polar flagellum showing catalase and oxidase activities. Growth was observed at 20-37 °C, pH 5.0-8.5 and 1.0-6.0 % (w/v) NaCl. Strain GTF13T contained C16:0, summed feature 3 (comprising C16 : 1 ω6c/C16 : 1 ω7c), summed feature 8 (comprising C18 : 1 ω6c/C18 : 1 ω7c) and C12 : 0 3-OH as major fatty acids and ubiquinone-9 and ubiquinone-8 as major quinones. Phosphatidylethanolamine and two unidentified phospholipids were detected as major polar lipids. The G+C content of the genomic DNA was 59.8 mol%. Strain GTF13T was most closely related to Simiduia agarivorans SA1T, Endozoicomonas montiporae CL-33T and Pseudomonas segetis FR1439T, belonging to different families or orders of the class Gammaproteobacteria, with less than 92.0 % 16S rRNA gene sequence similarities. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain GTF13T formed a phylogenetic lineage with the family Litoricolaceae, but the genome-based phylogenomic tree showed that strain GTF13T formed a distinct phylogenetic lineage within the order Oceanospirillales. The very low 16S rRNA gene sequence similarities and distinct phylogenetic relationships, together with distinct phenotypic and chemotaxonomic properties, served to differentiate strain GTF13T from phylogenetically closely related families. Here, strain GTF13T is proposed as a novel genus and species, for which the name Aestuariirhabdus litorea gen. nov., sp. nov. is proposed, within a new family Aestuariirhabdaceae fam. nov. of the order Oceanospirillales. The type strain is GTF13T (=KACC 19788T=JCM 32043T).

Dominance of Gas-Eating, Biofilm-Forming Methylobacterium Species in the Evaporator Cores of Automobile Air-Conditioning Systems.

Microbial communities in the evaporator core (EC) of automobile air-conditioning systems have a large impact on indoor air quality, such as malodor and allergenicity. DNA-based microbial population analysis of the ECs collected from South Korea, China, the United States, India, and the United Arab Emirates revealed the extraordinary dominance of Methylobacterium species in EC biofilms. Mixed-volatile organic compound (VOC) utilization and biofilm-forming capabilities were evaluated to explain the dominance of Methylobacterium species in the ECs. The superior growth of all Methylobacterium species could be possible under mixed-VOC conditions. Interestingly, two lifestyle groups of Methylobacterium species could be categorized as the aggregator group, which sticks together but forms a small amount of biofilm, and the biofilm-forming group, which forms a large amount of biofilm, and their genomes along with phenotypic assays were analyzed. Pili are some of the major contributors to the aggregator lifestyle, and succinoglycan exopolysaccharide production may be responsible for the biofilm formation. However, the coexistence of these two lifestyle Methylobacterium groups enhanced their biofilm formation compared to that with each single culture.IMPORTANCE Air-conditioning systems (ACS) are indispensable for human daily life; however, microbial community analysis in automobile ACS has yet to be comprehensively investigated. A bacterial community analysis of 24 heat exchanger fins from five countries (South Korea, China, the United States, India, and the United Arab Emirates [UAE]) revealed that Methylobacterium species are some of the dominant bacteria in automobile ACS. Furthermore, we suggested that the predominance of Methylobacterium species in automobile ACS is due to the utilization of mixed volatile organic compounds and their great ability for aggregation and biofilm formation.

Rhodophyticola porphyridii gen. nov., sp. nov., isolated from a red alga, Porphyridium marinum.

A Gram-stain-negative, strictly aerobic and moderately halophilic bacterium, designated strain MA-7-27T, was isolated from a marine red alga, Porphyridium marinum, in the Republic of Korea. The cells of strain MA-7-27T were non-motile rods showing oxidase- and catalase-positive activities. Growth of strain MA-7-27T was observed at 15-45 °C (optimum, 30 °C), pH 5.0-9.0 (pH 7.0) and in the presence of 0.0-5.0 % (w/v) NaCl (2.0 %). Strain MA-7-27T contained C10 : 0, summed feature 1 (comprising iso-C15 : 1 h and/or C13 : 1 3-OH) and summed feature 8 (comprising C18 : 1 ω7c and/or C18 : 1 ω6c) as the major fatty acids. The only isoprenoid quinone detected was ubiquinone-10. The major polar lipids of strain MA-7-27T were phosphatidylglycerol, two unidentified phospholipids and two unidentified aminolipids. The G+C content of the genomic DNA was approximately 63.6 mol%. Strain MA-7-27T was most closely related to the type strains of Boseongicola aestuarii BS-W15T and Nioella nitratireducens SSW136T with 96.98 % and 96.12 % 16S rRNA gene sequence similarities, respectively, but phylogenetic analyses showed that strain MA-7-27T formed a clearly distinct phylogenic lineage from the closely related strains. The phenotypic, chemotaxonomic and molecular properties support that strain MA-7-27T represents a novel genus of the family Rhodobacteraceae, for which the name Rhodophyticola porphyridii gen. nov., sp. nov. is proposed. The type strain is MA-7-27T (=KACC 18805T=JCM 31537T).

Roseicella frigidaeris gen. nov., sp. nov., isolated from an air-conditioning system.

A Gram-stain-negative, facultatively aerobic bacterial strain, designated DB1506T, of the family Acetobacteraceae, was isolated from an air-conditioning system in the Republic of Korea. Colonies were pink- to rosy-coloured and cells were non-motile cocci with catalase- and oxidase-positive activities. Growth of strain DB1506T was observed at 20-37 °C (optimum, 30 °C), pH 5.5-8.5 (pH 7.0) and in the presence of 0-0.5 % (w/v) NaCl (0 %). Strain DB1506T contained summed feature 8 (comprising C18 : 1ω7c and/or C18 : 1ω6c) and C18 : 1 2-OH as major fatty acids and ubiquinone-10 as the sole isoprenoid quinone. Phosphatidylglycerol, phosphatidylethanolamine, unidentified phospholipids, unidentified aminolipids and unidentified polar lipids were detected as major polar lipids. The G+C content of the genomic DNA calculated from the whole genome sequence was 72.5 mol%. Strain DB1506T was most closely related to Paracraurococcus ruber NS89T, Dankookia rubra WS-10T and Siccirubricoccus deserti SYSU D8009T with 16S rRNA gene sequence similarities of 96.01, 95.88 and 95.44 %, respectively, but strain DB1506T formed a clearly distinct phylogenic lineage from them within the family Acetobacteraceae. On the basis of phenotypic, chemotaxonomic and molecular properties, strain DB1506T represents a novel species of a new genus within the family Acetobacteraceae, for which the name Roseicella frigidaeris gen. nov., sp. nov. is proposed. The type strain is DB1506T (=KACC 19791T=JCM 32945T).

Nocardioides currus sp. nov., isolated from a mobile car air-conditioning system.

A strictly aerobic Gram-stain-positive bacterial strain, designated IB-3T, was isolated from a car air-conditioning system in the Republic of Korea. Cells were non-motile rods showing catalase- and oxidase-positive reactions. Growth of IB-3T was observed at 20-40 °C (optimum, 25 °C), at pH 6.5-9.0 (optimum, pH 7.5) and in the presence of 0-1 % (w/v) NaCl (optimum, 0 %). Menaquinone-8 (H4) was detected as the predominant respiratory quinone and iso-C16 : 0, 10-methyl-C17 : 0, iso-C17 : 0, C18 : 1ω9c, C17 : 1ω8c, C18 : 0, 10-methyl-C18 : 0 (TBSA) and C17 : 0 were identified as the major cellular fatty acids. Phosphatidylglycerol, diphosphatidylglycerol, phosphatidylcholine and phosphatidylinositol were detected as the major polar lipids. The major cell wall peptidoglycan type was ll-2,6-diaminopimelic acid. The G+C content of the genomic DNA was 71.5 mol%. IB-3T was most closely related to Nocardioides terrigenaDS-17T with a 98.0 % 16S rRNA gene sequence similarity. The results of phylogenetic analyses based on 16S rRNA gene sequences indicated that IB-3T formed a distinct phylogenetic lineage within the genus Nocardioidesof the family Nocardioidaceae. On the basis of the phenotypic, chemotaxonomic and molecular features, IB-3T represents a novel species of the genus Nocardioides, for which the name Nocardioidescurrus sp. nov. is proposed. The type strain is IB-3T (=KACC 19522T=JCM 32672T).

Albirhodobacter confluentis sp. nov., isolated from an estuary.

A Gram-stain-negative and strictly aerobic, moderately halophilic bacterium, designated strain S1-47T, was isolated from estuary sediment in South Korea. Cells were non-motile rods showing oxidase- and catalase-positive activities. Growth was observed at 10-30 °C (optimum, 25 °C), at pH 5.0-8.0 (optimum, pH 6.0-7.0) and in the presence of 0-6.0 % (w/v) NaCl (optimum, 2.0 %). Strain S1-47T contained summed feature 3 (comprising C16 : 1ω7c and/or C16 : 1ω6c), summed feature 8 (comprising C18 : 1ω7c and/or C18 : 1ω6c) and C16 : 0 as major cellular fatty acids and ubiquinone-10 as the sole isoprenoid quinone. Phosphatidylethanolamine, an unidentified aminolipid, an unidentified phospholipid and three unidentified lipids were detected as polar lipids. The G+C content of the genomic DNA was 69.3 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain S1-47T formed a tight phylogenetic lineage with Albirhodobacter marinus N9T. Strain S1-47T was most closely related to Albirhodobactermarinus N9T with a 99.4 % 16S rRNA gene sequence similarity. DNA-DNA relatedness levels between strain S1-47T and the type strain of Albirhodobactermarinus were 49.8-52.2 %. Based on the phenotypic, chemotaxonomic and molecular features, strain S1-47T clearly represents a novel species of the genus Albirhodobacter, for which the name Albirhodobacter confluentis sp. nov. is proposed. The type strain is S1-47T (=KACC 18804T=JCM 31536T).

Sphingobacterium humi sp. nov., isolated from soil.

A Gram-stain-negative, facultatively aerobic bacterium, designated strain D1T, was isolated from soil in South Korea. Cells of strain D1T were non-motile rods with oxidase- and catalase-positive activities. Growth was observed at 15-40 °C (optimum, 30-37 °C), at pH 5.5-9.0 (optimum, pH 7.0-8.0) and in the presence of 0.0-5.0 % (w/v) NaCl (optimum, 0.0-1.0 %). The only respiratory quinone detected was menaquinone 7 (MK-7), and iso-C15 : 0, iso-C17 : 0 3-OH and summed feature 3 (comprising C16 : 1ω7c/C16 : 1ω6c) were identified as the major fatty acids. Phosphatidylethanolamine was the major polar lipid, and two unidentified glycophospholipids and four unidentified lipids were also detected as minor polar lipids. Sphingolipids, a typical chemotaxonomic feature of the genus Sphingobacterium, were detected. The G+C content of the genomic DNA was 43.6 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain D1T formed a phyletic lineage with Sphingobacterium hotanense XH4T within the genus Sphingobacterium. Strain D1T was most closely related to S. hotanense XH4T (98.1 % 16S rRNA gene sequence similarity) and Sphingobacterium cellulitidis R-53603T (97.2 %), and the DNA-DNA relatedness level between strain D1T and the type strain of S. cellulitidis was 43.1±0.7 %. Based on the phenotypic, chemotaxonomic and molecular features, strain D1T clearly represents a novel species of the genus Sphingobacterium, for which the name Sphingobacterium humi sp. nov. is proposed. The type strain is D1T (=KACC 18595T=JCM 31225T).

Distinct Histone Modifications Modulate DEFB1 Expression in Human Vaginal Keratinocytes in Response to Lactobacillus spp.

Vaginal commensal lactobacilli are considered to contribute significantly to the control of vaginal microbiota by competing with other microflora for adherence to the vaginal epithelium and by producing antimicrobial compounds. However, the molecular mechanisms of symbiotic prokaryotic-eukaryotic communication in the vaginal ecosystem remain poorly understood. Here, we showed that both DNA methylation and histone modifications were associated with expression of the DEFB1 gene, which encodes the antimicrobial peptide human ß-defensin-1, in vaginal keratinocyte VK2/E6E7 cells. We investigated whether exposure to Lactobacillus gasseri and Lactobacillus reuteri would trigger the epigenetic modulation of DEFB1 expression in VK2/E6E7 cells in a bacterial species-dependent manner. While enhanced expression of DEFB1 was observed when VK2/E6E7 cells were exposed to L. gasseri, treatment with L. reuteri resulted in reduced DEFB1 expression. Moreover, L. gasseri stimulated the recruitment of active histone marks and, in contrast, L. reuteri led to the decrease of active histone marks at the DEFB1 promoter. It was remarkable that distinct histone modifications within the same promoter region of DEFB1 were mediated by L. gasseri and L. reuteri. Therefore, our study suggested that one of the underlying mechanisms of DEFB1 expression in the vaginal ecosystem might be associated with the epigenetic crosstalk between individual Lactobacillus spp. and vaginal keratinocytes.