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.

Nonomuraea aurantiaca sp. nov., a novel cellulase-producing actinobacterium isolated from soil

A novel cellulase-producing actinobacterium, designated strain NEAU-L178T, was isolated from soil sample collected from Qiqihaer, Heilongjiang Province, PR China. A polyphasic study was carried out to determine the taxonomic status of the strain. On the basis of 16S rRNA gene sequence analysis, strain NEAU-L178T should be classified into the genus Nonomuraea and is closely related to Nonomuraea cavernae SYSU K10005T (99.31 % 16S rRNA gene sequence similarity), Nonomuraea glycinis NEAU-BB2C19T (98.75 %), Nonomuraea guangzhouensis NEAU-ZJ3T (98.75 %) and ‘Nonomuraea rhizosphaerae’ NEAU-mq18T (98.34 %). The digital DNA–DNA hybridization values between them are 27.1, 26.1, 42.0 and 30.9 %, and the whole-genome average nucleotide identity values between them are 83.1, 82.3, 90.3 and 85.8 %, respectively. The whole-cell hydrolysates contained glucose, ribose, arabinose and madurose. The menaquinones were identified as MK-9(H0), MK-9(H4) and MK-9(H2). The major fatty acids were C16 : 0, iso-C17 : 0 and C17 : 0 10-methyl. The detected polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, hydroxy-phosphatidylethanolamine, phosphatidylinositol and three unidentified phospholipids. The genomic DNA G+C content was 69.7 mol%. In addition, whole-genome analysis indicated that strain NEAU-L178T had the potential to degrade cellulose. Based on the phenotypic, genotypic, chemotaxonomic and phylogenetic data, strain NEAU-L178T can be differentiated from its close phylogenetic relatives and represents a novel species of the genus Nonomuraea , for which the name Nonomuraea aurantiaca sp. nov. is proposed. The type strain is NEAU-L178T (=JCM 34799T=CGMCC 4.7741T).

Nonomuraea montanisoli sp. nov., isolated from mountain forest soil

A novel actinomycete, strain SMC 257^T, was isolated from a soil sample collected from mountain forest, Nan Province, Thailand. Strain SMC 257^T formed tightly closed spiral spore chains on aerial mycelia. A polyphasic approach was used for the taxonomic study of this strain. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain SMC 257^T belonged to the genus Nonomuraea, and the closest phylogenetically related species were Nonomuraea roseoviolacea subsp. carminata JCM 9946^T (98.9 % 16S rRNA gene sequence similarity), Nonomuraea rhodomycinica TBRC 6557^T (98.4 %), and Nonomuraea roseoviolacea subsp. roseoviolacea JCM 3145^T (98.3 %). Genome sequencing revealed a genome size of 9.76 Mbp and a G+C content of 72.3 mol%. The genome average nucleotide identity (ANI) and the digital DNA-DNA hybridization (dDDH) values that distinguished this novel strain from its closest related species were species boundary of 95-96 % and 70 %, respectively. The cell wall peptidoglycan contained meso-diaminopimelic acid. The whole-cell sugars were glucose, ribose, madurose and mannose. The major menaquinone was MK-9(H₄). The polar lipid profile consisted of phosphatidylethanolamine, hydroxyphosphatidylethanolamine, lysophosphatidylethanolamine, diphosphatidylglycerol, N-phosphatidylglycerol, phosphatidylinositol and phosphatidylinositol mannosides. The predominant cellular fatty acids were C_17 : 0 10-methyl and iso-C_16 : 0. Based on comparative analysis of phenotypic, chemotaxonomic and genotypic data, strain SMC 257^T is considered to represent a novel species of the genus Nonomuraea, for which the name Nonomuraea montanisoli is proposed. The type strain is SMC 257^T (=TBRC 13065^T=NBRC 114772^T).

Nonomuraea typhae sp. nov., an endophytic actinomycete isolated from the root of cattail pollen (Typha angustifolia L.)

A novel endophytic actinomycete, designated strain p1410^T, was isolated from the root of cattail pollen (Typha angustifolia L.) and characterized using a polyphasic approach. The strain had morphological characteristics and chemotaxonomic properties identical to those of members of the genus Nonomuraea. It produced spiral chains of spores on aerial mycelium as well as forming a pseudosporangium. Whole-cell hydrolysates contained meso-diaminopimelic acid, glucose, ribose and madurose. The menaquinones detected were MK-9(H₂), MK-9(H₄) and MK-9(H₀). The major fatty acids were 10-methyl C_17 : 0, iso-C_16 : 0 and C_17 : 0. The polar lipids were diphosphatidylglycerol, phosphatidylmethylethanolamine, phosphatidylethanolamine, hydroxyphosphatidylethanolamine, phosphatidylinositol mannoside and an unknown glycolipid. The DNA G+C content of the draft genome sequence, consisting of 11.4 Mbp, was 70.9 mol%. Phylogenetic analysis of 16S rRNA gene sequences showed that strain p1410^T belongs to the genus Nonomuraea with the highest sequence similarity to Nonomuraea candida HMC10^T (98.6 %), but phylogenetically clustered with Nonomuraea endophytica YIM 65601^T (98.4 %) and Nonomuraea longicatena NRRL 15532^T (98.3 %). Based on its phenotypic characteristics, DNA-DNA relatedness and average nucleotide identity, the strain is considered to represent a novel species of the genus Nonomuraea, for which the name Nonomuraea typhae sp. nov. is proposed. The type strain is p1410^T (=CCTCC AA 2019044^T=JCM 33461^T).

Nonomuraea basaltis sp. nov., a siderophore-producing actinobacteria isolated from surface soil of basaltic parent material

A Gram-stain-positive, aerobic, spore-forming actinobacterial strain, designated 160415^T, was isolated from a surface soil sample, which was formed on basaltic parent material, collected from Samsun, Turkey. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain 160415^T clustered closely with species of the genus Nonomuraea, and showed the highest sequence similarity to Nonomuraea zeae NEAU-ND5^T, Nonomuraea candida HMC10^T and Nonomuraea turkmeniaca DSM 43926^T with 99.1%, 98.9% and 98.7%, respectively. Chemotaxonomic properties including major menaquinones, diaminopimelic acid, sugar and phospholipid profiles also confirmed the affiliation of the strain to the genus Nonomuraea. The DNA G+C content of strain 160415^T was 69.6 mol%. DNA-DNA hybridization and average nucleotide identity values between the strain and closely related type strains were less than the recommended cut-off values. On the basis of phylogenetic relationships, genotypic and phenotypic characterizations, strain 160415^T represents a novel species of the genus Nonomuraea, for which the name Nonomuraea basaltis sp. nov. is proposed. The type strain is 160415^T (= KCTC 39875^T = DSM 104309^T).

Genome sequence and comparative analysis of DRQ-2, the type strain of Nonomuraea indica

Strain DRQ-2^T (type strain of Nonomuraea indica) is worthy for genome sequencing, due to its ability to produce a wide variety of industrially important enzymes such as amylase, asparaginase, cellulase, gelatinase, glutaminase, and protease. Genome sequencing and comparison of strain DRQ-2^T is described in the present work. The genome size was estimated to be 8,288,417 (bp) that consisted of 59 contigs. The G + C content of the genome was 72.4%. A total of 7730 genes were predicted with two rRNAs and 64 tRNAs. The genome analysis of the strain DRQ-2^T showed the presence of a wide range of secondary metabolite gene clusters. Pan-Genomes Analysis Pipeline (PGAP) indicated that strain DRQ-2^T had large numbers of unique genes. The majority of N. indica DRQ-2^T genes encode for hypothetical proteins, indicating the functions of these ortholog clusters were still remain to be determined.

Polyphasic classification of Nonomuraea strains isolated from the Karakum Desert and description of Nonomuraea deserti sp. nov., Nonomuraea diastatica sp. nov., Nonomuraea longispora sp. nov. and Nonomuraea mesophila sp. nov

Five actinobacteria isolates, KC201^T, KC401, KC310^T, KC712^T and 6K102^T, were recovered from the Karakum Desert during an investigation of novel actinobacteria with biotechnological potential. A polyphasic approach confirmed the affiliation of the strains to the genus Nonomuraea. The strains showed chemotaxonomic and morphological properties consistent with their classification in the genus Nonomuraea. Furthermore, these strains clearly distinguished and formed well supperted clades in phylogenetic and phylogenomic trees. Low ANI and dDDH values and distinguishing phenotypic properties between isolates KC201^T, KC310^T, KC712^T and 6K102^T showed that these strains belonged to novel Nonomuraea species, the names proposed for these taxa are Nonomuraea deserti sp. nov., Nonomuraea diastatica sp. nov., Nonomuraea longispora sp. nov. and Nonomuraea mesophila sp. nov., with the type strains KC310^T (=CGMCC 4.7331^T =DSM 102919^T =KCTC 39774^T), KC712^T (=CGMCC 4.7334^T =DSM 102925^T =KCTC 39776), KC201^T (=CGMCC 4.7339^T =DSM 102917^T =KCTC 39781^T) and 6K102^T (=CGMCC 4.7541^T =JCM 32916), respectively.

Nonomuraea phyllanthi sp. nov., an endophytic actinomycete isolated from the leaf of Phyllanthus amarus

A novel actinomycete, strain PA1-10^T, isolated from the leaf of Phyllanthus amarus collected from Bangkok, Thailand, was characterized taxonomically using a polyphasic approach. This strain contained the characteristics consistent with those of members of the genus Nonomuraea. It formed short rugose spore chain on aerial mycelium. The diamino acid in cell wall peptidoglycan was meso-diaminopimelic acid. Galactose, glucose, madurose, mannose, and ribose were found in whole-cell hydrolysates. Predominant menaquinones were MK-9 (H₂), MK-9 (H₄), and MK-9 (H₆). Major cellular fatty acids were iso-C_16:0 and C_17:0 10-methyl. Phospholipid profiles were composed of phosphatidylinositol mannoside (PIM), lyso-phosphatidylethanolamine (lyso-PE), phosphatidylethanolamine (PE), methylphosphatidylethanolamine (PME), diphosphatidylglycerol (DPG), and phosphatidylglycerol (PG). The G + C content of DNA was 71.2 mol%. Strain PA1-10^T showed the highest 16S rRNA gene sequence similarity with Nonomuraea candida JCM 15928^T (98.35%) and shared the same node with Nonomuraea maritima JCM 18321^T in the phylogenetic tree analysis. Based on the phenotypic characteristics, DNA-DNA relatedness, and average nucleotide identity (ANI), the strain is considered to represent a novel species of the genus Nonomuraea, for which the name Nonomuraea phyllanthi is proposed. The type strain is PA1-10^T (= JCM 33073^T = NBRC 112774^T = TISTR 2497^T).

Nonomuraea lactucae sp. nov., a novel actinomycete isolated from rhizosphere soil of lettuce (Lactuca sativa)

A novel actinobacterium, designated strain NEAU-YG30T, was isolated from the rhizosphere soil of lettuce collected in Heilongjiang province, north-east China. The taxonomic position of the strain was investigated using a polyphasic approach. On the basis of 16S rRNA gene sequence analysis, strain NEAU-YG30T belongs to the genus Nonomuraea, and shared highest sequence similarity to Nonomuraea muscovyensis KCTC 29233T (97.9 %) and Nonomuraea indica CCTCC AA 209050T (97.6 %). The major menaquinone was identified as MK-9(H4). The major fatty acids were 10-methyl C17 : 0, C17 : 0, iso-C16 : 0 2-OH, iso-C16 : 0 and C16 : 0. The polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, hydroxyl-phosphatidylethanolamine, phosphatidylinositol, an unidentified phospholipid and three unidentified lipids. The genomic DNA G+C content of strain NEAU-YG30T was 70.5 mol%. DNA-DNA hybridization values between them were less than 70 %. On the basis of phenotypic, genotypic and phylogenetic data, strain NEAU-YG30T can be characterized to represent a novel species of the genus Nonomuraea, for which the name Nonomuraealactucae sp. nov. is proposed. The type strain is NEAU-YG30T (=JCM 32549T=CGMCC 4.7506T).

Nonomuraea rhizosphaerae sp. nov., an actinomycete isolated from the rhizosphere soil of a rubber tree (Hevea brasiliensis Muell. Arg)

A novel actinomycete, designated strain NEAU-mq18^T, was isolated from the rhizosphere soil of a rubber tree (Hevea brasiliensis Muell. Arg) collected from Xianglu Mountain in Heilongjiang Province, northeast China, and subjected to a polyphasic taxonomic study. The 16S rRNA gene sequence analysis showed that the isolate belongs to the genus Nonomuraea with high sequence similarity to Nonomuraea guangzhouensis NEAU-ZJ3^T (98.5%). Phylogenetic analysis based on 16S rRNA gene sequences indicated that the strain clusters phylogenetically with N. guangzhouensis NEAU-ZJ3^T and Nonomuraea glycinis NEAU-BB2C19^T. Moreover, key chemotaxonomic properties including the major menaquinones, fatty acid composition and phospholipid profile also confirmed the affiliation of the strain to the genus Nonomuraea. However, some physiological, morphological and biochemical properties, and low DNA-DNA relatedness values, enabled the strain to be differentiated from closely related species of the genus Nonomuraea. Thus, strain NEAU-mq18^T is concluded to represent a novel species of the genus Nonomuraea, for which the name Nonomuraea rhizosphaerae sp. nov. is proposed. The type strain is NEAU-mq18^T (=CGMCC 4.7431^T=DSM 105761^T).

Antimicrobial substances from the rare actinomycete Nonomuraea rhodomycinica NR4-ASC07T

Nonomuraea rhodomycinica NR4-ASC07^T is a rare actinomycete isolated from soil in Sirindhorn peat swamp forest. The crude extract of its culture broth exhibited antimicrobial and anticancer against diverse human pathogens and cancer cells. The chemical investigation of the crude extract led to the isolation of two new metabolites named nonomuric acid (1) and 3-hydroxy deoxydaunorubicinol aglycone (2), along with two known bioactive compounds [ε-rhodomycinone (3) and 7-deoxy-13-dihydrocarminomycinone (4)]. Compounds 1 and 3 showed antimalarial activity with the half maximal inhibitory concentration (IC₅₀) of 8.00 and 8.88 μg mL^-1, respectively. Compound 4 inhibited growth of Mycobacterium tuberculosis and Bacillus cereus at the minimum inhibitory concentrations of 50.0 and 12.50 μg mL^-1, respectively. Every compound exhibited cytotoxicity against cancer cells tested at IC₅₀ ≥ 6.34 μg mL^-1. These finding are the first report of bioactive metabolites produced by strain NR4-ASC07^T, suggesting that rare actinomycetes are yet promising sources for novel drug discovery.

Nonomuraea lycopersici sp. nov., isolated from the root of tomato plants (Solanum lycopersicum L.)

Two novel bacterial strains were isolated from the roots of tomato plants (Solanum lycopersicum L.) from Dengfeng, Henan Province, China. Phylogenetic analysis of 16S rRNA gene sequences showed that the isolates NEAU-DE8(1)^T and NEAU-HE1(2) are closely related to one another (99.6% similarity) and are closely relate to Nonomuraea zeae NEAU-ND5^T (98.3, 98.3%) and Nonomuraea gerenzanensis DSM 100948^T (98.3, 98.0%). Phylogenetic trees constructed based on 16S rRNA gene sequences revealed that both strains grouped with N. zeae NEAU-ND5^T within the clade comprising the members of the genus Nonomuraea. Moreover, key chemotaxonomic properties including major menaquinones, fatty acid composition and phospholipid profiles also confirmed the affiliation of the two strains to the genus Nonomuraea. However, DNA-DNA hybridization data, together with physiological and morphological properties, showed that two isolates could be readily distinguished from their close phylogenetic relatives. Thus, on the basis of these phenotypic and genotypic data, strains NEAU-DE8(1)^T and NEAU-HE1(2) are concluded to represent a novel species of the genus Nonomuraea, for which the name Nonomuraea lycopersici sp. nov. is proposed. The type strain is NEAU-DE8(1)^T (= CGMCC 4.7412^T = DSM 104642^T).

Nonomuraea glycinis sp. nov., a novel actinomycete isolated from the root of black soya bean [Glycine max (L.) Merr]

A novel actinomycete, designated strain NEAU-BB2C19T, was isolated from the root of black soya bean [Glycine max (L.) Merr] collected from Harbin, Heilongjiang Province, China, and characterized using a polyphasic approach. The strain was an aerobic, Gram-stain-positive actinomycete that formed extensively branched substrate mycelium and aerial hyphae. The predominant menaquinones were MK-9(H2) and MK-9(H0). The major cellular fatty acid profile consisted of iso-C16 : 0, 10-methyl C17 : 0 and 10-methyl C18 : 0. The polar lipid profile consisted of diphosphatidylglycerol, phosphatidylethanolamine, hydroxy-phosphatidylethanolamine, phosphatidylinositol, phosphatidylinositol mannoside, phosphatidylglycerol and glycolipid. The DNA G+C content was 68.2±0.4 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain NEAU-BB2C19T should be assigned to the genus Nonomuraea and formed a distinct branch with its closest neighbour Nonomuraea guangzhouensis NEAU-ZJ3T (98.75 % 16S rRNA gene sequence similarity). The morphological and chemotaxonomic properties of the strain were also consistent with those of members of the genus Nonomuraea. A combination of DNA-DNA hybridization results and some phenotypic characteristics indicated that strain NEAU-BB2C19T could be clearly differentiated from its closest phylogenetic relative. Thus, the strain is concluded to represent a novel species of the genus Nonomuraea, for which the name Nonomuraea glycinis sp. nov. is proposed. The type strain is NEAU-BB2C19T (=CGMCC 4.7430T=DSM 104838T).

Nonomuraea cavernae sp. nov., a novel actinobacterium isolated from a karst cave sample

A novel actinobacterial strain, designated SYSU K10005^T, was isolated from a soil sample collected from a karst cave in Xingyi county, Guizhou province, south-west China. The taxonomic position of the strain was investigated using a polyphasic approach. Cells of the strain were aerobic and Gram-stain-positive. On the basis of 16S rRNA gene sequence analysis, strain SYSU K10005^T was most closely related to the type strains of the genus Nonomuraea, and shared highest sequence similarity of 98.4 % with Nonomuraea candida HMC10^T. DNA-DNA hybridization values between the two strains were less than 70 %. The whole-cell hydrolysates of strain SYSU K10005^T contained meso-diaminopimelic acid (diagnostic diamino acid), and arabinose, madurose and rhamnose (whole-cell sugars). The major isoprenoid quinone was MK-9(H4), while the major fatty acids were iso-C16 : 0, 10-methyl C17 : 0, C17 : 1ω8c and C17 : 0. The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, hydroxyl-phosphatidylethanolamine, lyso-phosphatidylethanolamine, phosphatidylinositol, phosphatidylinositol mannosides, an unidentified lipid, two unidentified ninhydrin-positive phosphoglycolipids and two unidentified phospholipids. The genomic DNA G+C content of strain SYSU K10005^T was 64.2 mol%. On the basis of phenotypic, genotypic and phylogenetic data, strain SYSU K10005^T can be characterized to represent a novel species of the genus Nonomuraea, for which the name Nonomuraea cavernae sp. nov. is proposed. The type strain is SYSU K10005^T (=KCTC 39805^T=CGMCC 4.7368^T).