Actinocatenispora comari sp. nov., an endophytic actinomycete isolated from aerial parts of Comarum salesowianum.

A novel actinomycete, designated NUM-2625T, was isolated as an endophytic bacterium in aerial parts of Comarum salesowianum, an endemic species in the Altai, Himalaya mountain chain area, collected from Khasagt Khairkhan Mountain in Mongolia. The 16S rRNA gene sequence of strain NUM-2625T showed the highest similarity to Actinocatenispora thailandica TT2-10T (99.4 %), Actinocatenispora sera KV-744T (99.3 %), and Actinocatenispora rupis CS5-AC17T (97.7 %). Chemotaxonomic properties of strain NUM-2625T were essentially consistent with those of the genus Actinocatenispora, such as the presence of meso-diaminopimelic acid as the diagnostic diamino acid of the peptidoglycan, MK-9(H4) and MK-9(H6) as the major menaquinones, and iso-C16 : 0, iso-C15 : 0, iso-C14 : 0 3-OH, and anteiso-C17 : 0 as the major fatty acids. Meanwhile, digital DNA-DNA hybridization and average nucleotide identity values revealed a low relatedness between strain NUM-2625T and the other type strains of the genus Actinocatenispora. In addition, strain NUM-2625T exhibited several phenotypic properties that could be used to distinguish it from its closest relatives. Based on the results of polyphasic analyses, strain NUM-2625T represents a novel species in the genus Actinocatenispora, for which the name Actinocatenispora comari sp. nov. is proposed. The type strain is NUM-2625T (=NBRC 114660T=TBRC 13496T).

Catellatospora sichuanensis sp. nov., a novel actinobacterium isolated from soil.

A novel actinobacterium, designated strain H14505T, was isolated from a soil sample collected in Hong Yuan, Sichuan, southwest PR China. The temperature, pH and NaCl ranges for growth were determined to be 15-35 °C (optimum, 28 °C), 6.0-8.0 (optimum, pH 7.0) and 0-2 % (w/v; optimum without NaCl), respectively. The polar lipdis detected for strain H14505T were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol, glycolipid and four unidentified lipids. The predominant menaquinones of strain H14505T were MK-9(H4) and MK-9(H6), and the prevalent fatty acids (>10 %) were C18 : 1 ω9c, C17 : 1 ω8c, summed feature 5 (anteiso-C18 : 0/ C18 : 2 ω6,9c) and C16 : 0. Phylogenetic analysis based on 16S rRNA gene and whole-genome sequences indicated that strain H14505T showed high similarity to Catellatospora vulcania NEAU-JM1T (99.0 %) and Catellatospora paridis NEAU-CL2T (99.0 %), and formed a monophyletic clade within the the genus Catellatospora in the phylogenetic trees. However, the average nucleotide indentity and DNA-DNA hybridization values between strain H14505T and closely related Catellatospora species showed that it belonged to a distinct species. Furthermore, the results of morphological, physiological and biochemical tests allowed further phenotypic differentiation of strain H14505T from its closest relatives. Thus, it is proposed that strain H14505T represents a novel species of the genus Catellatospora, for which the name Catellatospora sichuanensis sp. nov. is proposed. The type strain of Catellatospora sichuanensis is H14505T (=JCM 32394T=CICC 11042T).

Marine Sediment Recovered Salinispora sp. Inhibits the Growth of Emerging Bacterial Pathogens and other Multi-Drug-Resistant Bacteria.

Marine obligate actinobacteria produce a wide variety of secondary metabolites with biological activity, notably those with antibiotic activity urgently needed against multi-drug-resistant bacteria. Seventy-five marine actinobacteria were isolated from a marine sediment sample collected in Punta Arena de La Ventana, Baja California Sur, Mexico. The 16S rRNA gene identification, Multi Locus Sequence Analysis, and the marine salt requirement for growth assigned seventy-one isolates as members of the genus Salinispora, grouped apart but related to the main Salinispora arenicola species clade. The ability of salinisporae to inhibit bacterial growth of Staphylococcus epidermidis, Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacer baumannii, Pseudomonas aeruginosa, and Enterobacter spp. was evaluated by cross-streaking plate and supernatant inhibition tests. Ten supernatants inhibited the growth of eight strains of S. epidermidis from patients suffering from ocular infections, two out of the eight showed growth inhibition on ten S. epidermidis strains from prosthetic joint infections. Also, it inhibited the growth of the remaining six multi-drug-resistant bacteria tested. These results showed that some Salinispora strains could produce antibacterial compounds to combat bacteria of clinical importance and prove that studying different geographical sites uncovers untapped microorganisms with metabolic potential.

Allorhizocola rhizosphaerae gen. nov., sp. nov., a new member of Micromonosporaceae isolated from rhizosphere soil of the plant Calligonum mongolicum.

The taxonomic position of an actinobacterium, designated CPCC 204380T, which was isolated from a rhizosphere soil sample of the plant Calligonum mongolicum collected from Xinjiang Province, China, was established using a polyphasic approach. Vegetative hyphae developed well and globose bodies formed from aged hyphae. Spore chains that differentiated from the vegetative hyphae contained non-motile rod-shaped spores. The peptidoglycan contained meso-diaminopimelic acid and 3-hydroxydiaminopimelic acid as the diagnostic amino acids. The acyl type of the peptidoglycan was glycolyl. Glucose, mannose, ribose and xylose were detected in whole-cell hydrolysates. The predominant menaquinone was MK-10(H8), followed by MK-10(H6) and MK-10(H4). The polar lipid profile consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol and phosphatidylinositol mannoside. The major fatty acids were iso-C15 : 0, iso-C16 : 0 and C17 : 1ω9c. The genomic G+C content was 64.9 mol%. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain CPCC 204380T should be placed in the family Micromonosporaceae, in which it formed a distinct lineage next to the genera Rhizocola, Catellatospora, Catelliglobosispora, Hamadaea and Allocatelliglobosispora. It shared the highest 16S rRNA gene sequence similarities with Rhizocola hellebori K12-0602T (96.1 %), Catellatospora chokoriensis 2-25/1T (95.9 %), Catelliglobosispora koreensis DSM 44566T (95.9 %), Hamadaea tsunoensis DSM 44101T (95.3 %) and Allocatelliglobosispora scoriae Sco-B14 T (94.2 %), and less than 94.0 % sequence similarity with other validly described species. The combination of phylogenetic analysis and phenotypic characteristics supported the proposal of strain CPCC 204380T as representing a novel species of a new genus in the family Micromonosporaceae, for which the name Allorhizocola rhizosphaerae gen. nov., sp. nov. is proposed. CPCC 204380T (=DSM 102292T=KCTC 39746 T) is the type strain of the type species.

Jishengella zingiberis sp. nov., isolated from root tissue of Zingiber montanum.

A novel actinomycete, strain PLAI 1-1T, which formed spiny single spore directly on substrate mycelium was isolated from root tissue of Zingiber montanum. The isolate contained meso-diaminopimelic acid and 3-hydroxydiaminopimelic acid in the cell-wall peptidoglycan. The acyl type of the cell-wall muramic acid was glycolyl. The whole-cell sugars of strain PLAI 1-1T were glucose, arabinose, xylose, ribose and a trace amount of mannose. The membrane phospholipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylserine and phosphatidylinositol. The major menaquinone was MK-9 (H4). The main cellular fatty acids were iso-C15 : 0 and C17 : 1ω8c. The G+C content of the genomic DNA was 70.6 mol%. 16S rRNA gene sequence analysis revealed that strain PLAI 1-1T was a member of the genus Jishengella and had the highest 16S rRNA gene sequence similarity to Jishengella endophytica DSM 45430T (99.2 %). Based on the data of physiological and biochemical tests, including the result of DNA-DNA hybridization, strain PLAI 1-1T represents a novel species of the genus Jishengella, for which the name Jishengellazingiberis sp. nov. is proposed. The type strain is PLAI 1-1T (=TBRC 7644T=NBRC 113144T).

Actinoplanes deserti sp. nov., isolated from a desert soil sample.

A novel actinomycete, designated strain YIM CF22T, was isolated from a desert soil sample collected from Turpan in Xinjiang Uyghur Autonomous Region, north-western China. The taxonomic position of the strain YIM CF22T is described based on a polyphasic approach. Strain YIM CF22T was found to form irregular sporangia on agar media. It contains meso-diaminopimelic acid in the cell wall peptidoglycan. The major menaquinone was identified as MK-9(H4); the polar lipids were identified as diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol, two unidentified phospholipids and two unidentified glycolipids. The whole cell sugars were found to be ribose, mannose, galactose, glucose and xylose. The major cellular fatty acids were found to be (> 5%) iso-C16:0 (43.5%), anteiso-C17:0 (10.2%), iso-C15:0 (7.1%), C17:1 ω8c (6.3%) and iso H-C16:1 (5.9%). The G+C content was determined to be 70.8%. 16S rRNA gene sequence analysis of strain YIM CF22T showed high similarity (97.0%) to Actinoplanes rishiriensis NBRC 108556T. The strain also showed high 16S rRNA gene sequence similarities to Verrucosispora sediminis CGMCC 4.3550T (96.9%) and Micromonospora tulbaghiae DSM 45142T (96.8%). Phylogenetic analysis based on the 16S rRNA gene sequence indicated that strain YIM CF22T clusters with A. rishiriensis NBRC 108556T, Actinoplanes globisporus JCM 3186T and Actinoplanes rhizophilus NEAU-A-2T. Based on the differential phenotypic characteristics and the results of DNA-DNA relatedness and phylogenetic analysis, it is proposed that strain YIM CF22T represents a novel species of the genus Actinoplanes, for which the name Actinoplanes deserti sp. nov. is proposed. The type strain is YIM CF22T (= KCTC 39543T = CCTCC AB2018113T).

Actinoplanes sediminis sp. nov., isolated from marine sediment.

An actinomycete strain M4I47T was isolated from sediment from Megas Gialos, Syros, Greece. The results of phylogenetic analysis of the 16S rRNA gene sequence of M4I47T indicated that the highest similarity was with Actinoplanes atraurantiacus Y16T (98.9 %), Actinoplanes deccanensis IFO 13994T (98.8 %), Actinoplanes digitatis IFO 12512T (98.1 %) and Actinoplanes abujensis A4029T (98.0 %). The cell wall of the novel isolate contained meso-diaminopimelic acid and the whole-cell sugars were xylose, arabinose and glucose. The predominant menaquinones were MK-9(H4), MK-9(H6) and MK-9(H2). The phospholipid profile comprised phosphatidylethanolamine, phosphatidylmethylethanolamine, phosphatidylinositol, phosphatidylinositol mannosides and an unknown phospholipid. The DNA G+C content was 71.5 mol%. Furthermore, a combination of DNA-DNA relatedness and some physiological and biochemical properties indicated that the novel strain could be readily distinguished from the most closely related species. On the basis of these phenotypic and genotypic data, M4I47T represents a novel species of the genus Actinoplanes, for which the name Actinoplanessediminis sp. nov. is proposed. The type strain is M4I47T (=CCTCC AA 2016022T=DSM 100965T).

Verrucosispora endophytica sp. nov., isolated from the root of wild orchid (Grosourdya appendiculata (Blume) Rchb.f.).

A novel endophytic filamentous bacterium strain A-T 7972T, was isolated from wild orchid Grosourdya appendiculata (Blume) Rchb.f. collected in Thailand. The bacterium developed single non-motile spores with warty surface on substrate mycelia. The taxonomic position was described using a polyphasic approach. The 16S rRNA gene sequence and phylogenetic analysis indicated that strain A-T 7972T belonged to the genus Verrucosispora and shared the highest sequence similarity with V. lutea YIM 013T (98.71 %) and V. gifhornensis DSM 44337T (98.53 %). The values of DNA-DNA relatedness that distinguished this novel strain from its closest species were below 70 %. The cell-wall peptidoglycan contained meso-diaminopimelic acid. The whole-cell sugars were mannose, ribose, glucose and xylose. The predominant menaquinone was MK-9(H4). The predominant fatty acids were branched fatty acids iso-C15 : 0 and iso-C16 : 0. The diagnostic phospholipids profile consisted of phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylinositol and phosphatidylinositol mannosides. The G+C content of the genomic DNA was 70.5 mol%. Based on its phenotypic, chemotaxonomic and genotypic characteristics, the new isolate A-T 7972T (=BCC 50981T=TBRC 6031T=NBRC 112512T) is proposed to be the type strain of novel species, Verrucosispora endophytica sp. nov.

Longispora urticae sp. nov., isolated from rhizosphere soil of Urtica urens L., and emended descriptions of the species Longisporaalbida and Longisporafulva.

Two Gram-stain-positive, aerobic actinomycete strains, designated NEAU-PCY-3T and NEAU-PCY-4, were isolated from rhizosphere soil of Urtica urens L. collected from Anshan, Liaoning Province, northeast PR China. The 16S rRNA gene sequence analysis showed that the two strains exhibited 99.9 % 16S rRNA gene sequence similarity with each other and that they were most closely to Longispora fulva DSM 45356T (98.7, 98.9 %) and Longispora albida JCM 11711T (97.1, 97.2 %). Phylogenetic analysis based on the 16S rRNA gene sequences indicated that the two strains were located in the same lineage and formed a cluster with the genus Longispora. Both strains were observed to contain MK-10(H4) and MK-10(H6) as the predominant menaquinones. The cell wall peptidoglycan was found to contain meso-diaminopimelic acid, d-glutamic acid, glycine and l-alanine. Whole-cell hydrolysates mainly contained galactose, ribose and xylose. The phospholipid profile contained diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol, several glycolipids and several unknown lipids. The major cellular fatty acids for strain NEAU-PCY-3T were iso-C16 : 0, iso-C17 : 0, anteiso-C17 : 0 and C18 : 1ω5c. The DNA-DNA hybridization value between strains NEAU-PCY-3T and NEAU-PCY-4 was 83.6±0.4 %, and the values between the two strains and their closest phylogenetic relatives, belonging to the genus Longispora, were well below 70 %, supporting that they represented a distinct genomic species. An array of phenotypic characteristics also differentiated the strains from their closely related species, the only two validly published Longispora species. On the basis of the genetic, chemotaxonomic and phenotypic properties, strains NEAU-PCY-3T and NEAU-PCY-4 were classified as representatives of a novel species of the genus Longispora, for which the name Longispora urticae sp. nov. is proposed. The type strain is NEAU-PCY-3T (=DSM 105119T=CCTCC AA 2017017T).

Classification of Actinoplanes sp. ATCC 33076, an actinomycete that produces the glycolipodepsipeptide antibiotic ramoplanin, as Actinoplanes ramoplaninifer sp. nov.

Strain ATCC 33076, which produces the antibiotic ramoplanin, was isolated from a soil sample collected in India, and it was classified as a member of the genus Actinoplanes on the basis of morphology and cell-wall composition. A phylogenetic analysis based on 16S rRNA gene sequences indicated that the strain forms a distinct clade within the genus Actinoplanes, and it is most closely related to Actinoplanes deccanensis IFO 13994T (98.71 % similarity) and Actinoplanes atraurantiacus Y16T (98.33 %). The strain forms an extensively branched substrate mycelium; the sporangia are formed very scantily and are globose with irregular surface. Spores are oval and motile. The cell wall contains meso-diaminopimelic acid and the diagnostic sugars are xylose and arabinose. The predominant menaquinone is MK-9(H6), with minor amounts of MK-9(H4) and MK-9(H2). Mycolic acids are absent. The diagnostic phospholipids are phosphatidylethanolamine, hydroxyphosphatidylethanolamine and phosphatidylglycerol. The major cellular fatty acids are anteiso-C17 : 0 and iso-C16 : 0, followed by iso-C15 : 0 and moderate amounts of anteiso-C15 : 0, iso-C17 : 0 and C18 : 1ω9c. The genomic DNA G+C content is 71.4 mol%. Significant differences in the morphological, chemotaxonomic and biochemical data, together with DNA-DNA relatedness between strain ATCC 33076 and closely related type strains, clearly demonstrated that strain ATCC 33076 represents a novel species of the genus Actinoplanes, for which the name Actinoplanes ramoplaninifer sp. nov. is proposed. The type strain is ATCC 33076T (=DSM 105064T=NRRL B-65484T).

Virgisporangium myanmarense sp. nov., a novel motile actinomycete isolated from an anthill soil in Myanmar.

An actinomycete strain, designated MM04-1133T, was isolated from an anthill soil sample collected in Bagan, Myanmar. To establish the taxonomic status of this strain, the isolate was subjected to a polyphasic approach. Strain MM04-1133T was Gram-staining positive, aerobic, motile and formed long and narrow sporangia directly above the surface of the substrate mycelium. Whole-cell hydrolysates of the strain contained 3-OH-diaminopimelic acid, arabinose, glucose, galactose, mannose, rhamnose and xylose. The predominant menaquinones were MK-10(H6) and MK-10(H8). The major cellular fatty acids were iso-C16:0 and anteiso-C17:0. The diagnostic phospholipid was phosphatidylethanolamine. The G+C content of the DNA was 69.1 mol%. Phylogenetic analysis based on 16S rRNA gene sequence revealed that strain MM04-1133T clustered within the genus Virgisporangium, with the sequence exhibiting highest similarity (98.5% identity) with Virgisporangium ochraceum NBRC 16418T. The strain grew in the presence of 0-1% (w/v) NaCl, at pH 5-8 and at 20-40 °C, with optimal growth at 30-37 °C. Based on phylogenetic analysis and chemotaxonomic and phenotypic data, we propose classifying this isolate as a novel species of the genus Virgisporangium, to be designated as Virgisporangium myanmarense sp. nov. The type strain is MM04-1133T (=NBRC 112733T=VTCC 910008T).

Production of N-acyl homoserine lactones by the sponge-associated marine actinobacteria Salinispora arenicola and Salinispora pacifica.

The structures of acyl homoserine lactone (AHL) compounds and their quantification were accomplished using an integrated liquid chromatography-mass spectrometry approach. The precursor and product ions, along with retention times of peaks, were searched against an in-house database of AHLs and structures confirmed by accurate mass and by comparison with authentic AHL standards. The two compounds, N-(3-oxodecanoyl)-L-homoserine lactone and N-(3-oxododecanoyl)-L-homoserine lactone, were characterised and quantified in Salinispora sp. cultures.

Mangrovihabitans endophyticus gen. nov., sp. nov., a new member of the family Micromonosporaceae isolated from Bruguiera sexangula.

A novel endophytic actinobacterium, designated strain S3Cf-2T, was isolated from a surface-sterilized bark of Bruguiera sexangula collected from Dongzhaigang National Nature Reserve in Hainan Province, China. Phylogenetic analysis based on 16S rRNA gene sequences suggested that strain S3Cf-2T fell within the family Micromonosporaceae and formed a distinct clade in the Micromonosporaceae phylogenetic tree. The 16S rRNA gene sequence similarity values between strain S3Cf-2T and the type species of 30 genera in the family Micromonosporaceae were 91.55-97.45 %. Strain S3Cf-2T formed extensively branched substrate mycelia without fragmentation. An oval or rod-like spore with a smooth surface was borne singly at the end of substrate mycelium. The novel isolate possessed meso-diaminopimelic acid as the diamino acid of the peptidoglycan, and glucose, galactose, mannose, arabinose, xylose and ribose as whole-cell sugars. The acyl type of the cell-wall peptidoglycan was glycolyl and mycolic acids were absent. The major polar lipids included diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol and an unknown aminolipid, corresponding to phospholipid type PII. The major menaquinones were MK-9(H6) and MK-9(H8). The major cellular fatty acids were iso-C16 : 0, anteiso-C15 : 0, anteiso-C17 : 0 and iso-C15 : 0. The G+C content of the genomic DNA was 71.4 mol%. On the basis of phylogenetic, phenotypic and chemotaxonomic analyses, strain S3Cf-2T represents a novel species of a new genus within the family Micromonosporaceae, for which the name Mangrovihabitans endophyticus gen. nov., sp. nov. is proposed. The type strain of the type species is S3Cf-2T (=DSM 100693T=CGMCC 4.7299T).

Verrucosispora sonchi sp. nov., a novel endophytic actinobacterium isolated from the leaves of common sowthistle (Sonchus oleraceus L.).

A novel actinobacterium, designated strain NEAU-QY3T, was isolated from the leaves of Sonchus oleraceus L. and examined using a polyphasic taxonomic approach. The organism formed single spores with smooth surface on substrate mycelia. Phylogenetic analysis based on the 16S rRNA gene sequence indicated that the strain had a close association with the genus Verrucosispora and shared the highest sequence similarity with Verrucosispora qiuiae RtIII47T (99.17 %), an association that was supported by a bootstrap value of 94 % in the neighbour-joining tree and also recovered with the maximum-likelihood algorithm. The strain also showed high 16S rRNA gene sequence similarities to Xiangella phaseoli NEAU-J5T (98.78 %), Jishengella endophytica 202201T (98.51 %), Micromonospora eburnea LK2-10T (98.28 %), Verrucosispora lutea YIM 013T (98.23 %) and Salinispora pacifica CNR-114T (98.23 %). Furthermore, phylogenetic analysis based on the gyrB gene sequences supported the conclusion that strain NEAU-QY3T should be assigned to the genus Verrucosispora. However, the DNA-DNA hybridization relatedness values between strain NEAU-QY3T and V. qiuiae RtIII47T and V. lutea YIM 013T were below 70 %. With reference to phenotypic characteristics, phylogenetic data and DNA-DNA hybridization results, strain NEAU-QY3T was readily distinguished from its most closely related strains and classified as a new species, for which the name Verrucosispora sonchi sp. nov. is proposed. The type strain is NEAU-QY3T (=CGMCC 4.7312T=DSM 101530T).

Actinoplanes subglobosus sp. nov., isolated from mixed deciduous forest soil.

A novel filamentous bacterial strain, A-T 5400T, which developed subglobose sporangia at the end of sporangiophores on substrate mycelia, was isolated from mixed deciduous forest soil collected in Thailand. The taxonomic position of this micro-organism was described using a polyphasic approach. The 16S rRNA gene sequence and phylogenetic analysis indicated that strain A-T 5400T belonged to the genus Actinoplanes and was most closely related to 'Actinoplanes hulinensis' NEAU-M9 (98.82 % 16S rRNA gene sequence similarity) and Actinoplanes philippinensis NBRC 13878T (98.75 %). The DNA-DNA relatedness values that distinguished the novel strain from the closest species were below 70 %. The cell-wall peptidoglycan contained meso-diaminopimelic acid. The whole-cell sugars were ribose, galactose, glucose and xylose. The predominant menaquinone was MK-9(H4). The diagnostic phospholipids were phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol and phosphatidylinositol. The predominant cellular fatty acids were unsaturated fatty acids C16 : 1, branched fatty acids iso-C16 : 0 and iso-C15 : 0. The G+C content of the genomic DNA was 71 mol%. Following evidence from phenotypic, chemotaxonomic and genotypic studies, the new isolate is proposed to represent a novel species of the genus Actinoplanes named Actinoplanes subglobosus sp. nov. The type strain is A-T 5400T (=BCC 42734T=TBRC 5832T=NBRC 109645T).

Actinorhabdospora filicis gen. nov., sp. nov., a new member of the family Micromonosporaceae.

The actinomycete strains K12-0408T and K12-0792 were isolated on CM-cellulose agar from rhizosphere soil of a pteridophytic plant collected in Tokyo prefecture, Japan. Their taxonomic positions were determined using a polyphasic approach. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strains K12-0408T and K12-0792 were positioned within the family Micromonosporaceae. The strains formed extensively branched aerial and substrate mycelia. Long chains of cylindrical spores with smooth surfaces were formed on aerial hyphae. The cell wall contained meso-diaminopimelic acid, and galactose, glucose, mannose and ribose were detected in whole-cell hydrolysates. The predominant menaquinones were MK-10(H4) and MK-10(H6). The major cellular fatty acids were anteiso-C17 : 0 and anteiso-C17 : 0 2-OH. The DNA G+C contents of strains K12-0408T and K12-0792 were 69.6 and 69.7 mol%, respectively. Based on data from the present polyphasic taxonomic study, strains K12-0408T and K12-0792 represent a novel genus, for which the name Actinorhabdospora gen. nov. is proposed, with strain K12-0408T (=NBRC 111897T=TBRC 5327T) as the type strain of the type species, Actinorhabdosporafilicis sp. nov.

Synthesis of silver nanoparticles from two acidophilic strains of Pilimelia columellifera subsp. pallida and their antibacterial activities.

Biosynthesis of silver nanoparticles (AgNPs) is an eco-friendly approach by using different biological sources; for example, plants and microorganisms such as bacteria, fungi, and actinobacteria. In this report, we present the biological synthesis of silver nanoparticles (AgNPs) by acidophilic actinomycetes SL19 and SL24 strains isolated from pine forest soil (pH < 4.0). The isolates based on 16S rRNA gene sequence were identified as Pilimelia columellifera subsp. pallida. The synthesized AgNPs were characterized by visual observations of colour change from light-yellow to dark-brown. The UV-vis spectra of AgNPs were recorded at 425 and 430 nm. The AgNPs were further characterized by Nanoparticle tracking analysis (NTA), Zeta potential, Fourier transform infrared spectroscopy (FTIR) and Transmission electron microscopy (TEM). FTIR analysis revealed the presence of proteins as a capping agent. TEM analysis confirmed the formation of spherical and polydispersed NPs of 12.7 and 15.9 nm sizes. The in vitro antibacterial activity of AgNPs alone and in combination with antibiotics was evaluated against clinical bacteria viz., Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and uropathogens such as Enterobacter, S. aureus, P. aeruginosa, K. pneumoniae, and E. coli. The lowest MIC (40 µg ml(-1) ) was demonstrated by AgNPs synthesized from SL24 against E. coli. However, the AgNPs of SL19 showed lowest MIC (70 µg ml(-1) ) against S. aureus. The activity of antibiotic was enhanced, when tested in combination with silver nanoparticles synthesized from both actinobacterial strains.

Dactylosporangium solaniradicis sp. nov., a novel actinobacterium isolated from a root of tomato (Solanum lycopersicum L.).

A novel actinobacterium, designated strain NEAU-FJL2(T), was isolated from a tomato root (Solanum lycopersicum L.) and characterised using a polyphasic approach. Morphological and chemotaxonomic properties of strain NEAU-FJL2(T) are consistent with the description of the genus Dactylosporangium. Finger-shaped sporangia were observed to form on short sporangiophores branching from the substrate hyphae. The cell wall peptidoglycan was found to contain meso- and 3-hydroxy-diaminopimelic acids; arabinose, mannose, rhamnose and xylose were found as whole-cell sugars. The phospholipid profile was found to consist of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol and phosphatidylinositol. The predominant menaquinones were identified as MK-9(H8) and MK-9(H6). The major fatty acids were identified as iso-C16:0, C16:1 ω7c and iso-C15:0. Phylogenetic analysis based on 16S rRNA gene sequences demonstrated that strain NEAU-FJL2(T) belongs to the genus Dactylosporangium, with Dactylosporangium sucinum JCM 19831(T) (99.3 % 16S rRNA gene sequence similarity), Dactylosporangium darangshiense JCM 17441(T) (99.2 %), Dactylosporangium fulvum JCM 5631(T) (98.9 %) and Dactylosporangium roseum JCM 3364(T) (98.8 %) as the nearest phylogenetic relatives. However, a combination of DNA-DNA hybridization results and some phenotypic characteristics demonstrated that strain NEAU-FJL2(T) can be distinguished from them. Consequently, it is proposed that strain NEAU-FJL2(T) represents a novel species of the genus Dactylosporangium, for which the name Dactylosporangium solaniradicis sp. nov. is proposed. The type strain is NEAU-FJL2(T) (=CGMCC 4.7302(T) = DSM 100814(T)).

Plantactinosporasoyae sp. nov., an endophytic actinomycete isolated from soybean root [Glycine max (L.) Merr].

A novel actinomycete, designated strain NEAU-gxj3T, was isolated from soybean root [Glycine max (L.) Merr.] collected from Harbin, Heilongjiang Province, China, and characterized using a polyphasic approach. The 16S rRNA gene sequence of strain NEAU-gxj3T showed highest similarity to those of Micromonospora equina Y22T (98.2 %) and Plantactinospora endophytica YIM 68255T (98.0 %). Phylogenetic analysis based on the 16S rRNA gene and gyrB gene demonstrated that the isolate clustered with the members of the genus Plantactinospora. The chemotaxonomic properties of strain NEAU-gxj3Twere also consistent with those of members of the genus Plantactinospora. The cell wall contained meso-diaminopimelic acid and whole-cell sugars were xylose, glucose and galactose. The predominant menaquinones were MK-10(H6), MK-9(H8), MK-10(H2) and MK-10(H4). The polar lipid profile consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol and phosphatidylinositol mannoside. The major fatty acids were identified as anteiso-C17 : 0, iso-C16 : 0, iso-C15 : 0 and C15 : 0. A combination of DNA-DNA hybridization result and some phenotypic characteristics indicated that strain NEAU-gxj3Tcould be differentiated clearly from its closest phylogenetic relatives. Therefore, the strain is concluded to represent a novel species of the genus Plantactinospora, for which the name Plantactinospora soyae sp. nov. is proposed. The type strain is NEAU-gxj3T (=CGMCC 4.7221T=DSM 46832T).

Phytohabitans kaempferiae sp. nov., an endophytic actinomycete isolated from the leaf of Kaempferia larsenii.

A novel endophytic actinomycete, designated strain KK1-3T, which formed single spores and long chains of spores (more than 10 spores) was isolated from surface-sterilized Kaempferia larsenii leaf collected from Ubon Ratchathani province, Thailand. The isolate contained l-lysine, meso-diaminopimelic acid and hydroxyl diaminopimelic acid in the cell-wall peptidoglycan. The whole-cell sugars included glucose, mannose, rhamnose, ribose, galactose and xylose. The characteristic phospholipids were phosphatidylethanolamine, phosphatidylmethylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylinositol and phosphoglycolipids. The predominant menaquinones were MK-10(H8), MK-10(H6) and MK-10(H4). The predominant cellular fatty acids were anteiso-C17 : 0 and iso-C16 : 0. The G+C content of the genomic DNA was 71 mol%. Phylogenetic analysis using 16S rRNA gene sequences revealed that strain KK1-3T should be classified as representing a member of the genus Phytohabitans. The similarity values of sequences between this strain and those of the closely related species, Phytohabitans houttuyneae K11-0057T (99.0 %), Phytohabitans suffuscus K07-0523T (98.9 %), Phytohabitans flavus K09-0627T (98.6 %) and Phytohabitans rumicisK11-0047T (98.1 %) were observed. The DNA-DNA hybridization result and some physiological and biochemical properties indicated that KK1-3T could be readily distinguished from its closest phylogenetic relatives. On the basis of these phenotypic and genotypic data, this strain represents a novel species, for which the name Phytohabitans kaempferiae sp. nov. is proposed. The type strain is strain KK1-3T (=BCC 66360T =NBRC 110005T).