Discovery of a Novel Chromone Enantiomer and the Precursors of Nonactic Acid from the Coral-Reef-Derived Streptomyces sp. SCSIO 66814.

Three pairs of enantiomers (1-3)-the new 12R-aloesol (1a) and two new fatty acids (2 and 3)-and one new natural product (4) together three known compounds (5-7) were isolated from a coral-reef-derived Streptomyces sp. SCSIO 66814. Their structures were determined through extensive spectroscopic analysis, chiral analysis, and single-crystal X-ray diffraction data. Compounds 2 and 3 were presumed to be intermediates for further generating homononactic acid (5) and nonactic acid, and the latter two molecules were able to act as precursors to form macrotetrolides with remarkable biological activity. The isolation of related precursors, compounds 2-5, provided more evidence to support the proposal of a plausible biosynthetic pathway for nonactic acid and its homologs. Additionally, (+)-1 exhibited a weak activity against DPPH radicals.

Paenimyroides aestuarii gen. nov. sp. nov., a novel bacterium isolated from sediment in the Pearl River Estuary and reclassification of five Flavobacterium and four Myroides species.

An aerobic, Gram-negative, non-motile, yellow-to-orange pigmented and round bacterium, designated strain SCSIO 72103T, was isolated from sediment collected in the Pearl River Estuary, Guangdong Province, PR China and subjected to a polyphasic taxonomic study. Growth occurred at 20-37 °C (optimum, 28 °C), pH 6-8 (optimum, pH 7) and with 1-5.5% NaCl (optimum, 1-3 %). Comparative 16S rRNA gene analysis indicated that strain SCSIO 72103T had the highest similarities to Flavobacterium baculatum SNL9T (94.7 %) and Myroides aquimaris SW105T (94.2 %). Phylogenetic analysis based 16S rRNA gene sequences showed that strain SCSIO 72103T formed a single clade with M. aquimaris SW105T. Strain SCSIO 72103T contained iso-C15 : 0 as the major fatty acid and the predominant respiratory quinone was menaquinone MK-6. These characteristics are consistent with those of F. baculatum SNL9T and M. aquimaris SW105T. Phosphatidylethanolamine, most notably, unidentified aminolipid and unidentified aminophospholipid were major polar lipids. Strain SCSIO 72103T had a single circular chromosome of 2.96 Mb with a DNA G+C content of 35.1 mol%. The average nucleotide identity, average amino acid identity (AAI) and digital DNA-DNA hybridization values showed that the pairwise similarities between SCSIO 72103T and the type strains of F. baculatum SNL9T and M. aquimaris SW105T were 78.5-80.5 %, 79.0-81.4 % and 22.7-22.8 %, respectively. The AAI values between species in this clade and the type species of Flavobacterium and Myroides were below the 65 % threshold, indicating that these species belong to a novel genus. On the basis of phylogenetic, physiological and chemotaxonomic characteristics, strain SCSIO 72103T represents a new species of a novel genus, for which the name Paenimyroides aestuarii gen. nov. sp. nov. is proposed. The type strain is SCSIO 72103T (=KCTC 92043T=MCCC 1K06659T). It is also proposed that nine known species in the genera Flavobacterium and Myroides are reclassified as Paenimyroides species.

Pontibacter qinzhouensis sp. nov., isolated from rhizosphere soil of a mangrove plant Rhizophora stylosa.

A novel bacterium of the genus Pontibacter, designated GY10130T, was isolated from rhizosphere soil of a mangrove plant Rhizophora stylosa collected from Guangxi province, China. Strain GY10130T was Gram-stain negative, positive for oxidase activities, aerobic, short rod-shaped cells without flagella. Growth was observed at 10-40 °C (optimum, 28 °C), pH 6.0-9.0 (optimum, 7.0) and NaCl concentrations of 0-4% (optimum, 1%). Strain GY10130T is closely related to members of the genus Pontibacter, namely P. beigongshangensis CGMCC 1.17104T (97.8%) and P. amylolyticus CGMCC 1.12749T (95.0%), P. humi SWU8T (94.7%), and less than 94.0% with other currently described type strains of Pontibacter. The strain GY10130T showed an ANI value of 80.6% and dDDH value of 23.2% with P. beigongshangensis CGMCC 1.17104T, followed by P. amylolyticus CGMCC 1.12749T with ANI and dDDH values of 72.9 and 13.8%, respectively. Strain GY10130T contains carotenoid-like pigments, but flexirubin-type pigments were absent. The cellular fatty acids (> 10%) consist of summed feature 4 (17:1 iso I/anteiso B) and iso-C15:0. The predominant menaquinone is MK-7. The polar lipids comprise phosphatidylethanolamine, two unidentified glycolipids, two unidentified aminolipids and six unidentified phospholipids. The genome length of strain GY10130T was 6.2 Mbp with a DNA G + C content of 47.1 mol% and 4727 protein-coding genes. The result of polyphasic taxonomic study show strain GY10130T represents one novel species of Pontibacter, Pontibacter qinzhouensis sp. nov., with the type strain GY10130T (=NBRC 113901T = CGMCC 1.16772T).

Nocardioides coralli sp. nov., an actinobacterium isolated from stony coral in the South China Sea.

A Gram-stain-positive, aerobic, non-pigmented and non-motile actinobacterium, designated strain SCSIO 67246T, was isolated from a stony coral sample collected from the Sanya sea area, Hainan province, China. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain SCSIO 67246T shared the highest similarities with Nocardioides rotundus MCCC 1A10561T (96.5 %) and Nocardioides sonneratiae KCTC 39565T (96.1%). The novel strain grew at 15-37 °C, at pH 5.0-10.0 and in the presence of 0-10 % (w/v) NaCl. The genome length of strain SCSIO 67246T was 3.52 Mbp with a DNA G+C content of 72.0 mol% and 3397 protein-coding genes. The novel strain showed an average nucleotide identity value of 76.5 % and a digital DNA-DNA hybridization value of 20.1 % with N. rotundus MCCC 1A10561T. Strain SCSIO 67246T contained MK-8(H4) as the major menaquinone. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol and five phospholipids. The major cellular fatty acids were iso-C16 : 0, C17 : 1 ω8c and summed feature 9 (iso-C17 : 1 ω9c/10-methyl C16 : 0). ll-2,6-Diaminopimelic acid was the diagnostic diamino acid. The whole-cell sugars were galactose, glucose and ribose. Based on this polyphasic taxonomic study, strain SCSIO 67246T represents a novel species of the genus Nocardioides, for which the name Nocardioides coralli sp. nov. is proposed. The type strain is SCSIO 67246T (=MCCC 1K06251T=KCTC 49719T).

Halo- and Thiocarbazomycins from Coral- and Coral Reef Sands-Derived Actinomycetes.

Four actinomycete strains isolated from the coral Acropora austera and coral sand samples from the South China Sea, were found to produce a series of halogenated compounds baring similar ultraviolet absorption based on the analysis of HPLC and LC-MS. The production titers of halogenated compounds from Streptomyces diacarni SCSIO 64983 exceeded those of other similar strains leading us to focus on SCSIO 64983. Four new thiocarbazomycins A-B (1-2), chlocarbazomycin E (3), and brocarbazomycin A (4), together with three known chlocarbazomycins A-C (5-7) containing a carbazole core were identified, and their structures were determined using a combination of spectroscopic analysis including HRESIMS, 1D and 2D NMR. Structurally speaking, compounds 1 and 2 have the rare sulfur-containing carbazole nuclei, and 3 and 4 contain Cl and Br atoms, respectively. Although these compounds have not yet been found to have obvious biological activity, their discovery highlights the role of molecular libraries in subsequent drug discovery campaigns.

Flavimobilis rhizosphaerae sp. nov., isolated from rhizosphere soil of Spartina alterniflora.

A novel Gram-stain positive, facultatively anaerobic, motile, irregularly rod-shaped bacterium, designated GY 10621T, was isolated from rhizosphere soil of Spartina alterniflora in Beihai City, Guangxi Province, PR China, and characterized using a polyphasic taxonomic approach. GY 10621T was positive for catalase and oxidase. Growth occurred at 4-42 °C (optimum 30-37 °C), at pH 5.0-9.0 (optimum pH 7.0) and in the presence of 0-5% NaCl (w/v) (optimum 1-3%). The main menaquinones were MK-9 (H4) (92.2 %) and MK-10 (7.8 %). The major cellular fatty acids were anteiso-C15 : 0 and C14 : 0. The peptidoglycan was the type A4α (l-Lys-Ser-d-Glu). The polar lipids included four phosphoglycolipids, four glycolipids, an unidentified lipid and six unidentified phospholipids. The DNA G+C content of the type strain was 71.7 mol%. On the basis of the results of 16S rRNA gene analysis, the type strain of a species with a validly published name with the highest similarity to GY 10621T was Flavimobilis soli KCTC 13155T (97.16 %), followed by Sanguibacter suarezii NBRC 16159T (96.39 %). The calculated results indicated that compared with GY 10621T, the average nucleotide identity (ANI) values of three strains closely related to GY 10621T (the two aforementioned type strains and 'S. massiliensis' Marseille-P3815) were 74.18-94.97 %, and the digital DNA-DNA hybridization (dDDH) values were 20.3-60.6 %. The results of 16S rRNA-based and genome-based phylogenetic tree analysis indicated that GY 10621T should be assigned to the genus Flavimobilis. On the basis of evidence from polyphasic studies, GY 10621T should be designated as representing a novel species of the genus Flavimobilis, for which the name Flavimobilis rhizosphaerae sp. nov. is proposed. The type strain is GY 10621T (=CGMCC 1.17411T=KCTC 49515T).

Crenobacter intestini sp. nov., Isolated from the Intestinal Tract of Konosirus punctatus.

A novel Gram-stain-negative bacterium, designated strain GY 70310T, was isolated from the intestinal tract of Konosirus punctatus collected from Minjiang River, China. Cells of the strain were rod-shaped and motile with a single polar flagellum. The result of 16S rRNA gene sequence analyses showed that strain GY 70310T was moderately related to Crenobacter luteus YIM 78141T (94.7%), Paludibacterium paludis KBP-21T (93.8%) and Crenobacter cavernae K1W11S-77T (93.0%). The draft genome of strain GY 70310T consisted of 3.4 Mbp with DNA G+C content of 66.3 mol%, which possessed genes putatively encoding nitrate reductase, nitrite oxidoreductase and urease. The novel strain showed a whole genome average nucleotide identity (OrthoANI) value of 77.1% and a digital DNA-DNA hybridization (dDDH) value of 22.4% with Crenobacter luteus DSM 27258T, followed by Crenobacter cavernae K1W11S-77T with OrthoANI and dDDH values of 76.4% and 20.6%, respectively. The major fatty acids (>10%) were identified as summed feature 3 (C16:1ω6c and/or iso-C15:0 2-OH, C16:1ω7c), C16:0 and C18:1ω7c. The major respiratory quinone was ubiquinone-8 (Q-8). The polar lipids comprised diphosphatidylglycerol, phosphatidylethanolamine, one unidentified aminophospholipid, one unidentified lipid and one unidentified phospholipid. On the basis of phylogenetic analyses, genotypic and chemotaxonomic characteristics, strain GY 70310T represents a novel species of the genus Crenobacter, for which the name Crenobacter intestini sp. nov., is proposed. The type strain is GY 70310T (= CGMCC 1.16821T = KCTC 62945T = NBRC 113900T).

Actinomarinicola tropica gen. nov. sp. nov., a new marine actinobacterium of the family Iamiaceae, isolated from South China Sea sediment environments.

A novel marine actinobacterium, strain SCSIO 58843T, was isolated from the sediment sample collected from the South China Sea. Strain SCSIO 58843T was Gram-stain-positive, aerobic and rod shaped. The whole-cell hydrolysis of amino acids contained dd-DAP, alanine, glutamic acid, glycine and aspartic acid. The main menaquinone was MK-9(H8). The major fatty acids were C17 : 1 ω8c and C17 : 0. The major phospholipids were diphosphatidylglycerol (DPG), phosphatidylinositol (PI), phospatidylcholine (PC) and phosphatidylinositolmannoside (PIM). The G+C content of the genomic DNA was 72.5 %. Phylogenetic analysis of the 16S rRNA gene sequences showed that strain SCSIO 58843T formed a new lineage in the family Iamiaceae and had the highest similarity of 93.8 % with Iamia majanohamensis DSM 19957T. Strain SCSIO 58843T can be distinguished from these known genera in the family Iamiaceae by polyphasic data analyses, and represents a novel genus and novel species, for which Actinomarinicola tropica gen. nov., sp. nov is proposed with the type strain SCSIO 58843T(=KCTC 49408T=CGMCC 1.17503T).

Naasia lichenicola sp. nov., an actinobacterium isolated from lichen.

A Gram-stain-positive, yellow-pigmented, catalase-positive and oxidase-negative, strictly aerobic actinobacterium, designated strain YIM 131853T, was isolated from lichen collected from the South Bank of the Baltic Sea. The novel strain was non-spore-forming, short rod-shaped and motile with a single polar flagellum. The strain could grow at 4-37 °C (optimum, 28 °C), at pH 4.0-12.0 (pH 6.0) and at 0-3 % (w/v) NaCl (1 %). The DNA G+C content of strain YIM 131853T based on the draft genome sequence was 68.3 mol%. Predominant cellular fatty acids (>10 %) were identified as anteiso-C15 : 0, anteiso-C17 : 0 and iso-C16 : 0. The polar lipid profile included diphosphatidylglycerol, dimannosyldiacylglycerol, three unknown glycolipids, two unknown phospholipids and one unknown lipid. Strain YIM 131853T had 2,4-diaminobutyric acid as the diagnostic cell-wall diamino acid, galactose and glucose as whole-cell sugars, and MK-10, MK-14, MK-13 and MK-12 as the major menaquinones. Although strain YIM 131853T exhibited a highest 16S rRNA gene sequence similarity (96.6 %) to Amnibacterium kyonggiense NBRC 109360T, phylogenetic analysis based on 16S rRNA gene sequences indicated that the strain formed a tight lineage with Naasia aerilata NBRC 108725T (96.5 % 16S rRNA gene sequence similarity), which was the only species of genus Naasia. Based on the results of phenotypic, chemotaxonomic and phylogenetic analyses, strain YIM 131853T should belong to the genus Naasia and represents a novel species of the genus Naasia, for which the name Naasia lichenicola sp. nov. is proposed. The type strain is YIM 131853T (=CGMCC 4.7565T=NBRC 113605T).

Aureimonas leprariae sp. nov., Isolated from a Lepraria sp. Lichen.

A Gram-negative, motile, aerobic and coccoid rod-shaped bacterium, designated strain YIM132180T, was isolated from a Lepraria sp. lichen collected from Pu'er, Yunnan Province, China. The strain grew at 15-35 °C (optimum, 25-28 °C), at 0-2% (w/v) NaCl (optimum, 0-1%) and at pH 6.0-9.0 (optimum, pH 7.0). The 16S rRNA gene sequence showed that strain YIM132180T had highest similarity (96.4%) with Aureimonas endophytica 2T4P-2-4T, followed by Aureimonas ureilytica NBRC 106430T (95.7%) and Aureimonas rubiginis CC-CFT034T (95.6%). Phylogenetic analysis showed that the strain grouped with species of the genus Aureimonas. The genomic sequence was 4,779,519 bp and contained 4584 coding sequences (CDSs), 54 RNA genes, 3 complete rRNA genes and 47 tRNA genes. The major fatty acids (>10%) of strain YIM132180T were C18:1ω7c, C-16:0 and C19:0 cyclo ω8c. The predominant menaquinone was ubiquinone 10 (Q-10). The polar lipid profile comprised diphosphatidylglycerol, phosphatidylcholine, phosphatidylmethylethanolamine, phosphatidylethanolamine, phosphatidylglycerol, unidentified phospholipid, amino lipid, lipid and most importantly sulfoquinovosyldiacylglycerol (SQDG). Based on the draft genome sequence, the G +C content of strain YIM132180T was 68.4 mol%. The results of the polyphasic taxonomic study, including phenotypic, chemotaxonomic, and phylogenetic analyses, showed that strain YIM132180T represents a novel species of the genus Aureimonas, for which the name Aureimonas leprariae sp. nov. is proposed. The type strain is YIM 132180T (=KCTC 72462T = CGMCC 1.17389T).