Pradimicin U, a promising antimicrobial agent isolated from a newly found Nonomuraea composti sp. nov.

Pradimicin U is a new dihydrobenzo[a]naphthacenequinone compound found to be active on a screen designed to investigate compounds with antimicrobial activity, produced by the actinomycete designated strain FMUSA5-5T. The strain was isolated from a bio-fertilizer of Musa spp. collected from Suphanburi province, Thailand. The chemotaxonomic characteristics and 16S rRNA gene analysis revealed that strain FMUSA5-5T is a member of the genus Nonomuraea. Low genome-based taxonomic criteria, average nucleotide identity (ANI) (82.8-88.3%), average amino-acid identity (AAI) (79.4-87.3%), and digital DNA-DNA hybridization (dDDH) (29.5-38.5%) values and several phenotypic differences between strain FMUSA5-5T and its closest type strains of the genus Nonomuraea indicated that strain FMUSA5-5T represents a novel species of the genus Nonomuraea and the name Nonomuraea composti sp. nov. is proposed for the strain. The crude extract from the culture broth of strain FMUSA5-5T displayed promising antimicrobial activity against several pathogens and led to the isolation of a novel secondary metabolite, pradimicin U. Interestingly, this compound displayed a broad spectrum of biological activities such as antimalarial activity against Plasmodium falciparum K1 (IC50 value = 3.65 µg/mL), anti-Mycobacterium tuberculosis H37Ra (MIC value = 25.0 µg/mL), anti-Alternaria brassicicola BCC 42724 (MIC value = 25.0 µg/mL), anti-Bacillus cereus ATCC 11778 and anti-Staphylococcus aureus ATCC 29213 (MIC values = 6.25 and 1.56 µg/mL, respectively). Moreover, the compound possessed strong anti-human small cell lung cancer (NCI-H187) activity with IC50 value of 5.69 µg/mL, while cytotoxicity against human breast cancer (MCF-7) and Vero cells was very weak (IC50 values of 52.49 and 21.84 µg/mL, respectively).

Antimicrobial properties of unusual eremophilanes from the endophytic Diaporthe sp. BCC69512.

Six undescribed infrequent eremophilane derivatives including diaportheremopholins A - F and its previously undescribed side chain (E)-2-methyloct-2-enoic acid, together with three known compounds (testacein, xestodecalactones B and C), were isolated from the endophytic fungus Diaporthe sp. BCC69512. The chemical structures were determined based on NMR spectroscopic information in conjunction with the evidence from NOESY spectrum, Mosher's application, and chemical reactions for corroborating the absolute configurations. The isolated compounds were evaluated for biological properties such as antimalarial, anti-TB, anti-phytopathogenic fungal, antibacterial activities and for cytotoxicity against malignant (MCF-7 and NCI-H187) and non-malignant (Vero) cells. Diaportheremopholins B (2) and E (5) possessed broad antimicrobial activity against Mycobacterium tuberculosis, Bacillus cereus, Alternaria brassicicola and Colletotrichum acutatum with MICs in a range of 25.0-50.0 µg/mL. Testacein (7) exhibited strong anti-A. brassicicola and anti-C. acutatum activities with equal MIC values of 3.13 µg/mL. Moreover, diaportheremopholin F (6) and compound 8 displayed antitubercular activity with equal MIC values of 50.0 µg/mL. All tested compounds were non-cytotoxic against MCF-7, NCI-H187, and Vero cells, except those compounds 2 and 5-7 exhibited weak cytotoxicity against both malignant and non-malignant cells with IC50 values in a range of 15.5-115.5 µM.

Actinomycetospora termitidis sp. nov., an insect-derived actinomycete isolated from termite (Odontotermes formosanus).

Strain Odt1-22T, an insect-derived actinomycete was isolated from a termite (Odontotermes formosanus) that was collected from Chanthaburi province, Thailand. Strain Odt1-22T was aerobic, Gram-stain-positive, and produced bud-like spore chain on the substrate hypha. According to chemotaxonomic analysis, strain Odt1-22T contained meso-diaminopimelic acid in peptidoglycan and the whole-cell hydrolysates contained arabinose, galactose, glucose, and ribose. The major menaquinone was MK-8(H4). The diagnostic phospholipids were diphosphatidylglycerol, hydroxyphosphatidylethanolamine, phosphatidylethanolamine and phosphatidylglycerol. Phylogenetic analysis based on 16 S rRNA gene sequence revealed that strain Odt1-22T was identified to the genus Actinomycetospora and showed high similarity values with A. chiangmaiensis DSM 45062 T (99.24%), A. soli SF1T (99.24%) and A. corticicola 014-5 T (98.17%). The genomic size of strain Odt1-22T was 6.6 Mbp with 73.8% G + C content and 6355 coding sequences (CDSs). The genomic analysis, strain Odt1-22T and closely related species A. chiangmaiensis DSM 45062 T, A. soli SF1T and A. corticicola DSM 45772 T displayed the values of average nucleotide identity-blast (ANIb) at 83.7-84.1% and MUMmer (ANIm) at 86.6-87.0%. Moreover, the results of digital DNA-DNA hybridization values between strain Odt1-22T and related Actinomycetospora species were 45.8-50.5% that lower than the threshold value of commonly used to delineate separated species level. On the basis of phenotypic, chemotaxonomic, and genotypic data, strain Odt1-22T represented a novel species within the genus Actinomycetospora, for which the name Actinomycetospora termitidis sp. nov. is proposed. The type strain of the species is Odt1-22T (= TBRC 16192 T = NBRC 115965 T).

Frenolicins H and I from the caterpillar-associated Streptomyces sp. TBRC17107.

Two undescribed frenolicins H and I (1 and 2) along with six previously described frenolicin analogues [frenolicins A (3), B (4), UCF76-B (5), E - G (6 - 8)] and two anthraquinones [3,8-dihydroxy-1-propylanthraquinone-2-carboxylic acid (9) and 3,8-dihydroxy-1-propylanthraquinone (10)] were isolated from a longkong bark eating caterpillar-derived Streptomyces sp. TBRC17107. The chemical structures were determined by NMR spectroscopic information and HRESIMS data. Frenolicins H (1) and I (2) showed weak cytotoxicity against malignant and non-malignant cells. Frenolicins A (3) and B (4) showed antimalarial activity against Plasmodium falciparum (IC50 17.4 and 1.37 µM), antibacterial activity against Bacillus cereus and Staphylococcus aureus (MIC 50.0 and 0.20 µg/mL). Only frenolicin B had anti-plant pathogenic fungal activity against Collectotrichum acutatum and Alternaria brassicicola with MIC values of MIC 1.56 and 6.25 µg/mL, respectively. Frenolicins A and G possessed anti-Mycobacterium tuberculosis with equal MICs of 25.0 µg/mL.

Streptomyces rugosispiralis sp. nov., a Novel Actinobacterium Isolated from Peat Swamp Forest Soil That Produces Ansamycin Derivatives and Nocardamines.

Actinomycetes, especially the genus Streptomyces, are one of the most promising sources of bioactive natural products. In this study, a novel Streptomyces strain, RCU-064T, was isolated from a soil sample collected from a peat swamp forest in Thailand. Strain RCU-064T showed the highest 16S rRNA gene sequence similarity (99.06%) with Streptomyces malaysiensis NBRC 16446T. Based on a polyphasic approach, strain RCU-064T represents a novel species of the genus Streptomyces, for which the name Streptomyces rugosispiralis sp. nov. is proposed. The chemical isolation of the crude ethyl acetate extracts of the strain led to the isolation of six compounds: (1) geldanamycin, (2) 17-O-demethylgeldanamycin, (3) reblastatin, (4) 17-demethoxyreblastatin, (5) nocardamine, and (6) dehydroxynocardamine. These compounds were evaluated for their biological activities. All compounds showed no antimicrobial activity against tested microorganisms used in this study. Compounds (1)-(4) displayed cytotoxic activity against the NCI-H187 cell line, with IC50 values ranging from 0.045-4.250 µg/mL. Cytotoxicity against the MCF-7 cell line was found in compounds (1) and (3) with IC50 values of 3.51 and 1.27 µg/mL, respectively. Compounds (5) and (6) exhibited cytotoxicity only against Vero cells (IC50 of 16.57 µg/mL) and NCI-H187 cells (IC50 of 13.96 µg/mL), respectively. These results indicate that peat swamp forest soil remains a promising reservoir of novel actinomycetes capable of producing bioactive natural products.

Streptomyces zingiberis sp. nov., an endophytic actinobacterium isolated from the root tissue of Zingiber montanum.

An endophytic actinobacterium, designated strain PLAI 1-29T, was isolated from the root tissue of Zingiber montanum collected from Pathum Thani province, Thailand. Strain PLAI 1-29T was characterized using a polyphasic taxonomic approach. It typically exhibited morphological and chemotaxonomic properties of the genus Streptomyces. Strain PLAI 1-29T produced a spiral spore chain on aerial mycelium and grew at 15-40 °C, pH 6-10 on International Streptomyces Project 2 agar. The maximum NaCl concentration for growth was 9 % (w/v). Cells of strain PLAI 1-29T presented ll-diaminopimelic acid, arabinose, galactose and ribose. The detected phospholipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylinositol and phosphatidylinositol mannoside. The major menaquinones were MK-9(H6) and MK-9(H8). The major cellular fatty acids were iso-C16 : 0, anteiso-C15 : 0 and anteiso-C17 : 0. The genome-based taxonomic details revealed the assignment of strain PLAI 1-29T to the genus Streptomyces and exhibited low threshold values for the delineation of a novel species by average nucleotide identity-blast (84.0%), average amino acid identity (80.0%) and digital DNA-DNA hybridization (27.6%) with its closest type strain, Streptomyces xinghaiensis S187T. Furthermore, several differential physiological and biochemical characteristics were detected between strain PLAI 1-29T and the closest type strain. Based on the combined phenotypic and genomic features, strain PLAI 1-29T (=TBRC 7645T=NBRC 113170T) is considered to represent a new Streptomyces species, for which we propose the name Streptomyces zingiberis sp. nov.

Micromonospora solifontis sp. nov., an actinobacterium isolated from hot spring soil.

An actinobacterium strain, PPF5-17T, was isolated from hot spring soil collected from Chiang Rai province, Thailand. The strain exhibited morphological and chemotaxonomic properties similar to those of members of the genus Micromonospora. Colonies of PPF5-17T were strong pinkish red and turned black after sporulation in ISP 2 agar medium. Cells formed single spores directly on the substrate mycelium. Growth was observed from 15 to 45 °C and at pH 5-8. Maximum NaCl concentration for growth was 3 % (w/v). PPF5-17T was found to have meso-diaminopimelic acid, xylose, mannose and glucose in the whole-cell hydrolysate. Diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylinositol and phosphatidylinositolmannosides were observed as the membrane phospholipids. MK-10(H6), MK-9(H6), MK-10(H4) and MK-9(H4) were the major menaquinones. The predominant cellular fatty acids were iso-C15 : 0, iso-C17 : 0, anteiso-C17 : 0 and iso-C16 : 0. PPF5-17T shared the highest 16S rRNA gene sequence similarity with Micromonospora fluminis LMG 30467T (99.3 %). A genome-based taxonomic study revealed that PPF5-17T was closely related to Micromonospora aurantinigra DSM 44815T in the phylogenomic tree with an average nucleotide identity by blast (ANIb) of 87.7 % and a digital DNA-DNA hybridization (dDDH) value of, 36.1 % which were below the threshold values for delineation of a novel species. Moreover, PPF5-17T could be distinguished from its closest neighbours, M. fluminis LMG 30467T and M. aurantinigra DSM 44815T, with respect to a broad range of phenotypic properties. Thus, PPF5-17T represents a novel species, for which the name Micromonospora solifontis sp. nov. is proposed. The type strain is PPF5-17T (= TBRC 8478T = NBRC 113441T).

Streptomyces telluris sp. nov., a promising terrestrial actinobacterium with antioxidative potentials.

An actinomycete strain, AA8T, which produced a long straight chain of spores (verticillati type), was isolated from the rhizosphere soil of Mangifera indica in Bangkok, Thailand. A polyphasic taxonomic study was carried out to establish the taxonomic position of the strain. Strain AA8T formed a tight taxonomic position in the 16S rRNA gene tree with Streptomyces roseifaciens MBT76T. In contrast, the genome-based taxonomic analysis showed that strain AA8T shared low average nucleotide identity-BLAST (94.1%), the digital DNA-DNA hybridization (58.2%), and the average amino acid identity (93.6%) values with S. roseifaciens MBT76T. Moreover, a combination of physiological and biochemical properties indicated that strain AA8T was distinguished from all Streptomyces species with effectively published names. Strain AA8T, therefore, represents a novel species of Streptomyces, and the name Streptomyces telluris is proposed for the strain. The type strain is AA8T (= TBRC 8483T = NBRC 113461T). The chemical investigation led to the isolation of nine known compounds (compounds 1-9). Among these compounds, compound 7 (3,4-dihydroxybenzaldehyde) possesses strong antioxidant activity equal to ascorbic acid, a powerful antioxidative agent.

Gordonia aquimaris sp. nov., a novel marine actinobacterium isolated from seawater in the upper gulf of Thailand.

An actinobacterium strain, SW21T, was isolated from seawater collected in the upper Gulf of Thailand. Cells were Gram-stain-positive, aerobic and rod-shaped. Growth was observed from 15 to 37 °C and at pH 6-8. Maximum NaCl for growth was 14 % (w/v). meso-Diaminopimelic acid, arabinose, galactose, glucose, rhamnose and ribose were detected in the whole-cell hydrolysate. Diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol and phosphatidylinositol mannoside were detected as the phospholipids in the cells. The major menaquinones were MK-9(H2) and MK-7(H2). The major cellular fatty acids were C16 : 0, C18 : 1 ω9c, C18 : 0 and C18 : 010-methyl (TBSA). The 16S rRNA gene sequence data supported the assignment of strain SW21T to the genus Gordonia and showed that Gordonia mangrovi KCTC 49383T (98.7 %) was the closest relative. Moreover, the average nucleotide identity-blast (85.5 %) and digital DNA-DNA hybridization (30.7 %) values between strain SW21T and its closest neighbour were below the threshold values for delineation of a novel species. The combination of genotypic and phenotypic data indicated that strain SW21T is representative of novel species of the genus Gordonia. The name Gordonia aquimaris sp. nov. is proposed for strain SW21T. The type strain is SW21T (=TBRC 15691T=NBRC 115558T).

New insights into the neuroprotective and beta-secretase1 inhibitor profiles of tirandamycin B isolated from a newly found Streptomyces composti sp. nov.

Tirandamycin (TAM B) is a tetramic acid antibiotic discovered to be active on a screen designed to find compounds with neuroprotective activity. The producing strain, SBST2-5T, is an actinobacterium that was isolated from wastewater treatment bio-sludge compost collected from Suphanburi province, Thailand. Taxonomic characterization based on a polyphasic approach indicates that strain SBST2-5T is a member of the genus Streptomyces and shows low average nucleotide identity (ANI) (81.7%), average amino-acid identity (AAI) (78.5%), and digital DNA-DNA hybridization (dDDH) (25.9%) values to its closest relative, Streptomyces thermoviolaceus NBRC 13905T, values that are significantly below the suggested cut-off values for the species delineation, indicating that strain SBST2-5T could be considered to represent a novel species of the genus Streptomyces. The analysis of secondary metabolites biosynthetic gene clusters (smBGCs) in its genome and chemical investigation led to the isolation of TAM B. Interestingly, TAM B at 20 µg/mL displayed a suppressive effect on beta-secretase 1 (BACE1) with 68.69 ± 8.84% inhibition. Molecular docking simulation reveals the interaction mechanism between TAM B and BACE1 that TAM B was buried in the pocket of BACE-1 by interacting with amino acids Thr231, Asp 228, Gln73, Lys 107 via hydrogen bond and Leu30, Tyr71, Phe108, Ile118 via hydrophobic interaction, indicating that TAM B represents a potential active BACE1 inhibitor. Moreover, TAM B can protect the neuron cells significantly (% neuron viability = 83.10 ± 9.83% and 112.72 ± 6.83%) from oxidative stress induced by serum deprivation and Aß1-42 administration models at 1 ng/mL, respectively, without neurotoxicity on murine P19-derived neuron cells nor cytotoxicity against Vero cells. This study was reportedly the first study to show the neuroprotective and BACE1 inhibitory activities of TAM B.

Micromonospora thermarum sp. nov., an actinobacterium isolated from hot spring soil.

An actinomycete, designated strain HSS6-12T, was isolated from hot spring sediment collected from Ranong province, Thailand. The strain showed taxonomic characteristics consistent with those of members of the genus Micromonospora. HSS6-12T produced a single spore directly on the substrate mycelium, and no aerial mycelium was detected. The isomer of diamino acid presented in cell wall peptidoglycan was meso-diaminopimelic acid. Arabinose, xylose, glucose, and ribose were detected in whole-cell hydrolysates. MK-10(H4), MK-9(H4), and MK-10(H6) were major menaquinones. Major cellular fatty acids were iso-C16:0, iso-C15:0, and iso-C17:0. Phospholipid profile was composed of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylinositol, and phosphatidylinositolmannosides. 16S rRNA gene analysis revealed that HSS6-12T shared the highest 16S rRNA gene sequence similarity with Micromonospora inositola DSM 43819T (99.3%). In contrast, the genome analysis showed that HSS6-12T formed a tight taxonomic position in a phylogenomic tree with Micromonospora endolithica DSM 44398T. Moreover, the average nucleotide identity-blast, the digital DNA-DNA hybridization, and the average amino acid identity values between HSS6-12T and M. inositola DSM 43819T and M. endolithica DSM 44398T were 83.1-84.0%, 27.5-28.7%, and 80.4-82.2%, respectively, indicating that HSS6-12T was different species with both closely related Micromonospora-type strains. In addition, HSS6-12T could be discriminated from its closely related type strains by many physiological and biochemical characteristics. Thus, HSS6-12T could be considered a novel species of the genus Micromonospora, and the name Micromonospora thermarum is proposed for the strain. The type strain is HSS6-12T (= BCC 41915T = JCM 17127T).

Streptomyces macrolidinus sp. nov., a novel soil actinobacterium with potential anticancer and antimalarial activity.

A novel actinomycete, strain RY43-2T, belonging to the genus Streptomyces, was isolated from a peat swamp forest soil collected from Rayong Province, Thailand. The strain was characterized by using a polyphasic approach. The cell-wall peptidoglycan contained ll-diaminopimelic. Ribose and glucose were detected in its whole-cell hydrolysates. The strain contained anteiso-C15:0, iso-C14:0 and iso-C16:0 as the predominant fatty acids, and MK-9(H4), MK-9(H6) and MK-9(H8) as the major menaquinones. The phospholipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylinositol, phosphatidylinositol mannoside, three unidentified ninhydrin-positive phospholipids and two unidentified phospholipids. Strain RY43-2T showed the highest 16S rRNA gene similarity to Streptomyces misionensis JCM 4497T (98.9 %) and Streptomyces lichenis LCR6-01T (98.9 %). The draft genome of RY43-2T was 6.7 Mb with 6078 coding sequences with an average G+C content of 70.8 mol%. Genomic analysis revealed that the average nucleotide identity (ANI) values based on blast (ANIb) and MUMmer (ANIm) between strain RY43-2T and S. misionensis JCM 4497T were 80.1 and 86.1%, respectively. The ANIb and ANIm values between strain RY43-2T and S. lichenis LCR6-01T were 77.0 and 85.5%, respectively. The digital DNA-DNA hybridization values were 25.2 and 23.0% in comparison with the draft genomes of S. misionensis JCM 4497T and S. lichenis LCR6-01T, respectively. The results of taxonomic analysis suggested that strain RY43-2T represented a novel species of the genus Streptomyces for which the name Streptomyces macrolidinus sp. nov. is proposed. The type strain is RY43-2T (=TBRC 7286T=NBRC 115640T). Strain RY43-2T exhibited antimicrobial activity against Enterococcus faecium ATCC 51559, Colletotrichum capsici BMGC 106 and Colletotrichum gloeosporioides BMGC 107 with the minimum inhibitory concentration values of 25.0, 12.5, and 6.25 µg ml-1. It also exhibited potent antimalarial activity against Plasmodium falciparum K1 with IC50 of 0.0031 µg ml-1. In addition, it showed cytotoxicity against Vero, KB, MCF-7 and NCI-H187 with IC50 values of 0.0347, 6.15, 3.36 and 0.0352 µg ml-1, respectively.

Cellular responses to 8-methyl nonanoic acid, a degradation by-product of dihydrocapsaicin, in 3T3-L1 adipocytes.

BACKGROUND: Capsaicinoids, such as dihydrocapsaicin (DHC), exert the health-promoting effects of chili peppers on energy metabolism. The metabolic responses to capsaicinoids are primarily mediated through transient receptor potential cation channel subfamily V member 1 (TRPV1). However, the varying contributions of their metabolites to beneficial health outcomes remain unclear. 8-methyl nonanoic acid (8-MNA), a methyl-branched medium chain fatty acid (MCFA), is an in vivo degradation by-product of DHC. Since MCFAs have emerged as metabolic modulators in adipocytes, here we examined various cellular responses to 8-MNA in 3T3-L1 adipocytes. METHODS: The viability of 3T3-L1 adipocytes exposed to various concentrations of 8-MNA was assessed by the Calcein AM assay. Biochemical assays for lipid accumulation, AMP-activated protein kinase (AMPK) activity, lipolysis and glucose uptake were performed in 3T3-L1 adipocytes treated with 8-MNA during 48-h nutrient starvation or 5-day maturation. RESULTS: 8-MNA caused no impact on cell viability. During nutrient starvation, 8-MNA decreased lipid amounts in association with AMPK activation, a molecular event that suppresses lipogenic processes. Moreover, 3T3-L1 adipocytes that were treated with 8-MNA during 5-day maturation exhibited a reduced lipolytic response to isoproterenol and an increased glucose uptake when stimulated with insulin. CONCLUSIONS: These results suggest that 8-MNA derived from DHC modulates energy metabolism in adipocytes and also support the idea that the metabolic benefits of chili consumption are partly attributable to 8-MNA.

Antimalarial and antimicrobial substances isolated from the endophytic actinomycete, Streptomyces aculeolatus MS1-6.

Seven undescribed compounds, including four naphthoquinone terpenoids (aculeolatins A - D), one rare 2-nitropyrrole terpenoid (nitropyrrolin F), and two hydroxamate siderophores (aculeolamides A and B) and one further undescribed compound (2,5,7-trihydroxy-3,6-dimethylnaphthalene-1,4-dione), together with eleven known compounds (arromycin, phenaziterpene A, nitropyrrolin A, heronapyrroles A and B, salaceyin A, 5,7-dihydroxy-2-isopropylchromone, 1-hydroxyphenazine, 1-methoxyphenazine, 1-acetyl-ß-carboline, and N-(2-phenylethyl) acetamide), were isolated from the cultures of the endophytic Streptomyces aculeolatus MS1-6. The structures of the isolated compounds were determined using NMR spectroscopy and corroborated using chemical modification. These compounds exhibited a broad spectrum of biological activities, including antimalarial (IC50 6.03-9.84 µg/mL), antitubercular (MIC 3.13-6.25 µg/mL), anti-plant pathogenic fungal (MIC 25.0-50.0 µg/mL), and antibacterial (MIC 3.03-50 µg/mL) activities; however, they displayed unremarkable cytotoxicity against cancerous (MCF-7 and NCI-H187) and non-cancerous (Vero) cell lines.

Streptomyces sennicomposti sp. nov., an actinomycete isolated from compost of Senna siamea (Lam.).

A member of the genus Streptomyces, designated RCPT1-4T, was isolated from compost of Senna siamea (Lam.), collected from an agricultural area in Rayong province, Thailand. The spore morphology and the presence of ll-diaminopimelic acid in the peptidoglycan indicate that RCPT1-4T shows the typical properties of members of the genus Streptomyces. On the basis of the results of 16S rRNA gene sequence analysis, the strain should be classified as representing a member of the genus Streptomyces and was most closely related to Streptomyces fumigatiscleroticus NBRC 12999T with the highest 16S rRNA gene sequence similarity of 99.2 %, followed by Streptomyces spiralis NBRC 14215T (99.0 %). In addition, RCPT1-4T shared the highest average nucleotide identity by blast (ANIb) (86.0 %), and digital DNA-DNA hybridization (dDDH) (32.1 %) values with S. spiralis NBRC 14215T. Furthermore, several physiological and biochemical differences were observed between RCPT1-4T and the closely related type strains of species with validly published names. These taxonomic data indicated that RCPT1-4T could be considered to represent a novel species of the genus Streptomyces and the name Streptomyces sennicomposti sp. nov. is proposed for this strain. The type strain is RCPT1-4T (=TBRC 11260T=NBRC 114303T).

Streptomyces epipremni sp. nov., an endophytic actinomycete isolated from the root of Epipremnum aureum.

An endophytic Streptomyces-like micro-organism, designated strain PRB2-1T was isolated from root tissue of Epipremnum aureum (Linden and André) G.S. Bunting. The typical morphological and chemotaxonomic characteristics, i.e. the ability to produce straight spore chains directly on aerial mycelium and the presence of ll-diaminopimelic acid in cell-wall peptidoglycan, were consistent with its assignment to the genus Streptomyces. 16S rRNA gene analysis showed that strain PRB2-1T is a member of the genus Streptomyces with the highest similarity to Streptomyces bryophytorum DSM 42183T (98.4 %). Moreover, the draft genome sequence of strain PRB2-1T exhibited low average nucleotide identity by blast (79.9-83.8 %) and digital DNA-DNA hybridization (24.9-28.3 %) values to the reference strains, which were well below the species circumscription threshold. The DNA G+C content of genomic DNA was 73.6 mol%. Comparison of phenotypic characteristics and whole-genome sequence between strain PRB2-1T and its close relatives indicated that strain PRB2-1T could be classified as a novel species of the genus Streptomyces. Thus the name, Streptomyces epipremni sp. nov. is proposed for the strain. The type strain is PRB2-1T (=TBRC 7642T=NBRC 113169T).

Streptomyces acidipaludis sp. nov., an actinobacterium isolated from peat swamp forest soil.

An actinobacterium strain PLK6-54T was isolated from Lankwai peat swamp forest soil collected from Yala province, Thailand. Strain PLK6-54T exhibited morphological and chemotaxonomic properties described for the genus Streptomyces. It formed a spiral spore chain directly on aerial mycelium. Growth was observed between 20 and 40 °C and at pH 5-8. The maximum NaCl for growth was 2 % (w/v). ll-Diaminopimelic acid, arabinose and ribose were detected in the whole-cell hydrolysate. Diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylinositol and phosphatidylinositolmannoside were detected as the phospholipids. The major menaquinones were MK-10(H2) and MK-9(H6). The major cellular fatty acids were iso-C16 : 0, anteiso-C15 : 0 and iso-C14 : 0. 16S rRNA gene sequence data supported the assignment of strain PLK6-54T to the genus Streptomyces and showed that Streptomyces rubidus NBRC 102073T (99.0 %) was the closest relative. Moreover, the average nucleotide identity-blast (85.5 %) and digital DNA-DNA hybridization (30.7 %) values reported between strain PLK6-54T and its closest neighbour were below the threshold values for delineation of a novel species. Strain PLK6-54T could be distinguished from related validly described Streptomyces species by several phenotypic properties. The combination of genotypic and phenotypic data indicated that strain PLK6-54T is representative of a novel species of the genus Streptomyces. The name Streptomyces acidipaludis sp. nov. is proposed for strain PLK6-54T. The type strain is PLK6-54T (=TBRC 11250T=NBRC 114297T).

Streptomyces endocoffeicus sp. nov., an endophytic actinomycete isolated from Coffea arabica (L.).

An aerobic, non-motile, Gram-stain positive actinomycete, designated strain CA3R110T, was isolated from the surface-sterilised root of Coffea arabica L. collected from Lampang Province, Thailand. 16S rRNA gene sequence analysis indicated that strain CA3R110T was a member of the genus Streptomyces and showed the closest similarities to Streptomyces buecherae AC541T (99.2%), followed by Streptomyces rapamycinicus NRRL B-5491T (99.1%), Streptomyces luteoverticillatus NBRC 3840T (99.1%), Streptomyces coerulescens NBRC 12758T (99.1%), and Streptomyces iranensis HM 35T (99.0%). Strain CA3R110T contained LL-diaminopimelic acid in cell peptidoglycan, MK-9(H6), and MK-9(H8) as major menaquinone, iso-C16:0, iso-C15:0, C16:0 as major fatty acids. Diphosphatidylglycerol, phosphatidylethanolamine, hydroxy-phosphatidylethanolamine, phosphatidylglycerol, phosphatidylinositol, phosphatidylinositolmannoside were detected in the cell. The chemotaxonomic characteristics possessed the typical properties of the genus Streptomyces. A low digital DNA-DNA hybridization (< 55.7%) and average nucleotide identity-blast (ANIb) (< 92.2%) values revealed that strain CA3R110T could be distinguished from any known Streptomyces species. With the differences in phenotypic and genotypic data, strain CA3R110T represents a novel species of genus Streptomyces, for which the name Streptomyces endocoffeicus sp. nov. is proposed. The type strain is CA3R110T (= TBRC 11245T = NBRC 114296T).

Potential antibiotic production of Streptomyces justiciae sp. nov., isolated from the root of Justicia subcoriacea.

Endophytic actinobacterial strain 3R004T was isolated from a root of Justicia subcoriacea collected in Thailand. In this report, the taxonomic position of this strain is described using a polyphasic approach. Based on the morphological characteristics and chemical composition of its cells, strain 3R004T was identified as a member of the genus Streptomyces. It produced a long chain of cylindrical spores on aerial mycelia. ll-Diaminopimelic acid was detected in the cell wall peptidoglycan. The menaquinones were MK-9(H4), MK-9(H6) and MK-9(H8). C16 : 0, iso-C16 : 0, anteiso-C15 : 0 and iso-C15 : 0 were detected as the major cellular fatty acids. Polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylinositol and one unidentified lipid. Strain 3R004T showed the highest 16S rRNA gene similarity of 99.45 % to Streptomyces cyaneochromogenes MK-45T. The phylogenomic results indicated that strain 3R004T was close to Streptomyces aquilus GGCR-6T and Streptomyces antibioticus DSM 40234T. The DNA-DNA hybridization and average nucleotide identity values among strain 3R004T and closely related Streptomyces species were 35.5-63.1 % and 82.7-94.3 %, respectively. The type strain produced actinomycin D antibiotic as the major secondary metabolite. The maximum productivity of the actinomycin D (378 mg l-1) was observed when the strain was grown in 301 broth at 30 °C, 180 r.p.m. for 12 days. On the basis of phenotypic and genotypic evidence, strain 3R004T represents a novel species of the genus Streptomyces, for which the name Streptomyces justiciae is proposed. The type strain is 3R004T (=LMG 32138T=TBRC 13128T=NBRC 115065T).

Streptomyces musisoli sp. nov., an actinomycete isolated from soil.

An actinobacterium, strain CH5-8T, which formed spiral chains of spore arising from the aerial mycelium, was isolated from rhizosphere soil of Musa spp. The organism exhibited vivid greenish yellow substrate mycelium and easily produced the medium grey aerial spore mass on ISP2 medium. The typical chemotaxonomic properties of members of the genus Streptomyces were observed for strain CH5-8T, e.g. ll-diaminopimelic acid in cell peptidoglycan, MK-9(H8), MK-9(H6), and MK-9(H4) as major menaquinones and anteiso-C15 : 0, iso-C16 : 0, and anteiso-C17 : 0 as major fatty acids. Diphosphatidylglycerol, phosphatidylethanolamine, hydroxyphosphatidylethanolamine, phosphatidylglycerol, phosphatidylinositol and phosphatidylinositol mannoside were detected in the cells. A combination of morphological and chemotaxonomic data supported the assignment to the genus Streptomyces. The analysis result obtained for the 16S rRNA gene sequence confirmed the taxonomic affiliation at the genus level of this strain. The novel strain CH5-8T showed the highest 16S rRNA gene sequence values to Streptomyces echinatus NBRC 12763T (98.9 %), followed by Streptomyces actinomycinicus RCU-197T (98.9 %). The average nucleotide identity by blast (ANIb) and digital DNA-DNA hybridization values between CH5-8T and its closest relatives, S. echinatus CECT 3313T and S. actinomycinicus RCU-197T, were ≤91.6 % and ≤47.4 %, respectively. The digital DNA G+C content of genomic DNA was 72.1 mol%. On the basis of these phenotypic and genotypic data, strain CH5-8T represents a novel species, for which the name Streptomyces musisoli sp. nov. is proposed. The type strain is CH5-8T (=TBRC 9950T=NBRC 113997T).