Altererythrobacter lutimaris sp. nov., a marine bacterium isolated from a tidal flat and reclassification of Altererythrobacter deserti, Altererythrobacter estronivorus and Altererythrobacter muriae as Tsuneonella deserti comb. nov., Croceicoccus estronivorus comb. nov. and Alteripontixanthobacter muriae comb. nov

A yellow-coloured bacterium, designated strain JGD-16^T, was isolated from a tidal flat in Janggu-do, Garorim Bay, Taean-gun, Chungcheongbuk-do, Republic of Korea. Cells were Gram-stain-negative, aerobic, non-flagellated and short ovoid to coccoid-shaped. Growth was observed at 10-37 °C (optimum, 30 °C), pH 6.0-9.0 (pH 8.0) and with 1-5% (w/v) NaCl (2%). Results of 16S rRNA gene sequence analysis indicated that strain JGD-16^T was closely related to Altererythrobacter xiamenensis LY02^T (97.1 %), Altererythrobacter aurantiacus O30^T (96.3 %), Altererythrobacter ishigakiensis JPCCMB0017^T (95.8 %), Altererythrobacter epoxidivorans JCS350^T (95.7 %) and Altererythrobacter insulae BPTF-M16^T (95.3%). Phylogenomic analysis using the maximum-likelihood algorithm showed that strain JGD-16^T formed a clade with the genus Altererythrobacter. The genomic DNA G+C content was 57.8 mol%. The predominant respiratory quinone was ubiquinone-10. The major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, a sphingoglycolipid, an unidentified glycolipid and an unidentified lipid. The major fatty acids were C_18:1 ω7c (31.5 %) and C_18:3 ω6c (19.6 %). On the basis of its phylogenomic, physiological and chemotaxonomical characteristics, strain JGD-16^T represents a novel species within the genus Altererythrobacter, for which the name Altererythrobacter lutimaris JGD-16^Tsp. nov. is proposed. The type strain is JGD-16^T (=KCTC 72632^T=KACC 21405^T=JCM 33750^T). We also propose the reclassification of Altererythrobacter deserti as Tsuneonella deserti comb. nov., Altererythrobacter estronivorus as Croceicoccus estronivorus comb. nov. and Altererythrobacter muriae as Alteripontixanthobacter muriae comb. nov.

Actirhodobacter atriluteus gen. nov., sp. nov., isolated from the surface water of the Yellow Sea

A Gram-stain-negative, aerobic, orange-pigmented bacterial strain, designated HHU K3-1 ^T, was isolated from the surface water of the Yellow Sea. The strain was observed to grow on 2216E agar medium, and growth occurred at pH 6.0-8.0 (optimum 7.0), 28-37 °C (optimum 28 °C), and in the presence of 0.5-5% (w/v) NaCl (optimum 1-3%). The major fatty acids (> 10%) were summed feature 3 (C_16:1ω6c/C_16:1ω7c), C_17:1ω6c and summed feature 8 (C_18:1ω6c/C_18:1ω7c). Strain HHU K3-1 ^T was found to contain ubiquinone-10 as the predominant quinone and the major polar lipids were diphosphatidylglycerol (DPG), phosphatidylethanolamine (PE), phosphatidylglycerol (PG) and sphingoglycolipid (SGL). The 16S rRNA gene sequence analysis indicated that strain HHU K3-1 ^T shared highest similarities with Pelagerythrobacter marensis KCTC 22370 ^T (97.7%) and Qipengyuania oceanensis MCCC 1A09965^T (96.9%). However, a phylogenetic tree based on 288 orthologous clusters (OCs) indicated that HHU K3-1 ^T was close related to Parapontixanthobacter aurantiacus MCCC 1A09962^T. The pairwise AAI and evolutionary distance between HHU K3-1 ^T and Parapontixanthobacter aurantiacus MCCC 1A09962^T are 67.1% and 0.43, respectively, which meet the recently proposed standard to differentiate genera in the family Erythrobacteraceae. On the basis of the result obtained by the polyphasic taxonomic study, strain HHU K3-1 ^T can be considered to represent a novel genus in the family Erythrobacteraceae, for which the name Actirhodobacter atriluteus gen. nov., sp. nov. is proposed. The type strain is HHU K3-1 ^T (= MCCC 1K04225^T = KCTC 72834 ^T = CGMCC 1.17395 ^T).

Altererythrobacter muriae sp. nov., isolated from hypersaline Añana Salt Valley spring water, a continental thalassohaline-type solar saltern

A novel salt-tolerant alpha-proteobacterium, designated SALINAS58^T, was isolated from Santa Engracia hypersaline spring water in the Añana Salt Valley, Álava, Spain. The isolate was Gram-negative, aerobic, non-motile, catalase-positive, oxidase-negative, rod-shaped and formed orange colonies on marine agar. Optimal growth was observed at pH 6.0-6.5, at 30 °C and in the presence of 1% (w/v) NaCl. The main cellular fatty acids (>20%) were summed feature 8 (C_{18 : 1} ω7c and/or C_{18 : 1} ω6c) and summed feature 3 (C_{16 : 1} ω7c and/or C_{16 : 1} ω6c). The major respiratory quinone was ubiquinone Q-10 and the major polar lipids detected were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidilglycerol, four unidentified glycolipids and one unidentified phospholipid. Strain SALINAS58^T had the highest 16S rRNA gene sequence similarity to Altererythrobacter marensis MSW-14^T (96.6%), Altererythrobacter aquaemixtae JSSK-8^T (96.5%) and Pontixanthobacter luteolus SW-109^T (96.5%) followed by Altererythrobacter atlanticus 26DY36^T (96.4%). Results of the phylogenetic analysis, based on 16S rRNA gene sequences, and phylogenetic approaches based on whole genome nucleotide differences, showed that strain SALINAS58^T could be distinguished from recognized species of the genus Altererythrobacter. The genomic DNA G+C content was 61.4 mol%. Digital DNA-DNA hybridization, average nucleotide identity and average aminoacid identity values between the genome of strain SALINAS58^T and A. marensis MSW-14^T were 18.4, 73.1 and 68.1%, respectively. Based on data from this polyphasic characterization, strain SALINAS58^T (=CECT 30029^T=LMG 31726^T) is considered to be classified as representing a novel species in the genus Altererythrobacter, for which the name Altererythrobacter muriae sp. nov. is proposed.

Altererythrobacter segetis sp. nov., Isolated from Farmland Soil

A Gram-stain-negative bacterium, designated YJ20^T, was isolated from rhizosphere soil of a spinach farmland at Shinan in Korea. Strain YJ20^T was found to be aerobic, non-motile rods which can grow at 10-33 °C (optimum, 28 °C), at pH 6.5-8.5 (optimum, pH 6.5-7.5) and in the absence of NaCl. The 16S rRNA gene sequence analysis showed that strain YJ20^T belongs to the genus Altererythrobacter with moderate sequence similarities to Altererythrobacter dongtanensis KCTC 22672^T (96.8%), Altererythrobacter soli MN-1^T (96.6%) and Altererythrobacter xinjiangensis S3-63^T (96.5%). The phylogenomic analysis based on the whole-genome sequence demonstrated that strain YJ20^T formed a distinct phyletic line with Altererythrobacter soli MN-1^T and Altererythrobacter salegens XY-R17^T showing average nucleotide identity (ANI) values of 79.4 and 77.5%, respectively. The predominant ubiquinone was identified as Q-10, and the major fatty acids were C_17:1 ω6c, C_18:1 ω7c and C_15:0 2-OH. The major polar lipids were identified as diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidycholin, sphingoglycolipid, an unidentified glycolipid, an unidentified phospholipid and an unidentified lipid. The G+C content of the genome was determined to be 66.3 mol%. On the basis of phenotypic, chemotaxonomic properties and phylogenetic and phylogenomic analyses in this study, strain YJ20^T is considered to represent a novel species in the genus Altererythrobacter, for which the name Altererythrobacter segetis sp. nov. is proposed. The type strain is YJ20^T (= KACC 19554^T = NBRC 113199^T).

Phylogenetic Analysis and Screening of Antimicrobial and Antiproliferative Activities of Culturable Bacteria Associated with the Ascidian Styela clava from the Yellow Sea, China

Over 1,000 compounds, including ecteinascidin-743 and didemnin B, have been isolated from ascidians, with most having bioactive properties such as antimicrobial, antitumor, and enzyme-inhibiting activities. In recent years, direct and indirect evidence has shown that some bioactive compounds isolated from ascidians are not produced by ascidians themselves but by their symbiotic microorganisms. Isolated culturable bacteria associated with ascidians and investigating their potential bioactivity are an important approach for discovering novel compounds. In this study, a total of 269 bacteria were isolated from the ascidian Styela clava collected from the coast of Weihai in the north of the Yellow Sea, China. Phylogenetic relationships among 183 isolates were determined using their 16S rRNA gene sequences. Isolates were tested for antimicrobial activity against seven indicator strains, and an antiproliferative activity assay was performed to test for inhibition of human hepatocellular carcinoma Bel 7402 and human cervical carcinoma HeLa cell proliferation. Our results showed that the isolates belonged to 26 genera from 18 families in four phyla (Firmicutes, Actinobacteria, Proteobacteria, and Bacteroidetes). Bacillus and Streptomyces were the most dominant genera; 146 strains had potent antimicrobial activities and inhibited at least one of the indicator strains. Crude extracts from 29 strains showed antiproliferative activity against Bel 7402 cells with IC₅₀ values below 500 μg·mL^-1, and 53 strains showed antiproliferative activity against HeLa cells, with IC₅₀ values less than 500 μg·mL^-1. Our results suggest that culturable bacteria associated with the ascidian Styela clava may be a promising source of novel bioactive compounds.

Altererythrobacter aerophilus sp. nov., isolated from deep-sea water of the north-west Pacific

A Gram-stain-negative, rod-shaped bacterium, designated Ery1^T, was isolated from deep-sea seawater collected from the Mariana Trench and subjected to a polyphasic investigation for taxonomy. Strain Ery1^T was able to grow in medium containing 0-10 % NaCl (w/v; optimum, 0-1.0 %), pH 5.0-9.5 (optimum, pH 6.0-7.0) and at temperatures between 10-45 °C (optimum, 30-40 °C). The comparison of 16S rRNA gene sequences revealed that strain Ery1^T showed highest similarity to Altererythrobacterxinjiangensis S3-63^T (97.7 %) and Altererythrobacterrigui WW3^T (97.6 %), and exhibited less than 97.5 % sequence similarity to other type strains of the species with validly published names. Phylogenetic analyses indicated that strain Ery1^T fell within the cluster comprising the Altererythrobacter species and formed a coherent clade with Altererythrobacterxinjiangensis and Altererythrobactersoli. The OrthoANIu and in silico DNA-DNA hybridization values between strain Ery1^T and the reference strains were 73.8-75.9 % and 19.2-20.1 %, respectively. Strain Ery1^T contained Q-10 as the major respiratory quinone and Q-11 in a minor amount. The major fatty acids (>10 %) were summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c), summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c), C16 : 0, C18 : 1ω7c 11-methyl and C14 : 0 2-OH. The major polar lipids were sphingoglycolipid, diphosphatidylglycerol, phosphatidyglycerol, phatidylethanolamine, phosphatidylcholine and three unidentified glycolipids. Differential phenotypic properties, chemotaxonomic differences, phylogenetic distinctiveness, together with the genomic data demonstrated that strain Ery1^T represents a novel species of the genus Altererythrobacter, for which named as Altererythrobacter aerophilus sp. nov. with the type strain Ery1^T (=KCTC 62387^T=CGMCC 1.16499^T=MCCC 1A10037^T).

Altererythrobacter amylolyticus sp. nov., isolated from lake sediment

An aerobic, motile, Gram-stain-negative bacterium, designated strain NS1T, was isolated from interfacial sediment from Taihu Lake, China. The strain formed yellow colonies on R2A medium. Cells were ovoid to rod-shaped and non-spore-forming. Growth occurred at 15–40 °C (optimum, 28 °C), at pH 5.0–10.5 (optimum, 6.5–7.5) and in the presence of 0–1 % (w/v) NaCl (optimum, 0 %). Phylogenetic trees based on 16S rRNA gene sequences showed that strain NS1T represented a member of the genus Altererythrobacter and had the highest sequence similarity to Altererythrobacter troitsensis CCTCC AB 2015180T (97.1 %). The average nucleotide identity value between strain NS1T and the closest related strain based on their genomes was 78.6 %. The predominant ubiquinone was Q-10. The major fatty acids were summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c), summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c) and C16 : 0. The polar lipids comprised diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, an unidentified phospholipid, an unidentified glycolipid and six unidentified lipids. The genomic DNA G+C content was 66.6 mol%. On the basis of phenotypic and genotypic characteristics, strain NS1T represents a novel species of the genus Altererythrobacter , for which the name Altererythrobacter amylolyticus sp. nov. is proposed. The type strain is NS1T (=CGMCC 1.13679T=NBRC 113553T).

Altererythrobacter maritimus sp. nov., isolated from seawater

A rod-shaped, Gram-staining-negative and orange-pigmented bacterium, designated strain HME9302^T, was isolated from seawater of the Yellow Sea in the Republic of Korea. The phylogenetic tree based on 16S rRNA gene sequences showed that strain HME9302^T formed a lineage within the genus Altererythrobacter, and was most closely related to Altererythrobacter aurantiacus O30^T with 96.7 % sequence similarity. The major fatty acids were summed feature 8 (comprising C18 : 1ω7c and/or C18 : 1ω6c), summed feature 3 (comprising C16 : 1ω7c and/or C16 : 1ω6c) and C16 : 0. The major respiratory quinone was ubiquinone-10. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, sphingoglycolipid and four unidentified lipids. The DNA G+C content was 60.8 mol%. On the basis of the evidence presented in this study, strain HME9302^T represents a novel species of the genus Altererythrobacter, for which the name Altererythrobacter maritimus sp. nov. is proposed with the type strain HME9302^T (=KCTC 32463^T=KACC 17617^T=CECT 8417^T).

Altererythrobacter insulae sp. nov., a lipolytic bacterium isolated from a tidal flat

A lipolytic, Gram-stain-negative, aerobic, non-motile and coccoid, ovoid or rod-shaped bacterial strain, designated BPTF-M16^T, was isolated from tidal flat sediment on the Yellow Sea in the Republic of Korea. Strain BPTF-M16^T grew optimally at 30 °C and in the presence of 2.0-3.0 % (w/v) NaCl. A phylogenetic tree of 16S rRNA gene sequences showed that strain BPTF-M16^T fell within the clade comprising the type strains of Altererythrobacter species. Strain BPTF-M16^T exhibited 16S rRNA gene sequence similarity values of 98.0 and 97.1 % to the type strains of Altererythrobacterishigakiensis and Altererythrobactermarinus, respectively, and of less than 97.0 % to the type strains of the other recognized species. Strain BPTF-M16^T contained Q-10 as the predominant ubiquinone and C18 : 1ω7c as the major fatty acid. The major polar lipids detected in strain BPTF-M16^T were phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, sphingoglycolipid and one unidentified glycolipid. Mean DNA-DNA relatedness values of strain BPTF-M16^T with the type strains of A. ishigakiensis and A. marinus were 22 and 13 %, respectively. The average nucleotide identity value between strain BPTF-M16^T and the type strain of A. ishigakiensis was 76.80 %. Differential phenotypic properties, together with the phylogenetic and genetic data, revealed that strain BPTF-M16^T is separated from recognized Altererythrobacter species. On the basis of the data presented here, strain BPTF-M16^T is considered to represent a novel species of the genus Altererythrobacter, for which the name Altererythrobacter insulae sp. nov. is proposed. The type strain is BPTF-M16^T (=KCTC 62421^T=KACC 19609^T=NBRC 113190^T).