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Ten compounds (1–10) were obtained from soil-derived Penicillium cremeogriseum W1-1 with the antimicrobial guided isolation procedure. Among them, 4 presented broad-spectrum antimicrobial activities and its preliminary mechanisms were evaluated. Compound 4 showed growth inhibition on drug-resistant pathogenic strains Escherichia coli and Candida albicans with post-contact effect (PCE), changed the morphology and membrane structure, killed cells with leakage, inhibited the growth of C. albicans by eradicating biofilms. Interestingly, the fraction containing 4 presented in vivo anti-pathogenic activities in mice, indicating this indole diterpenoid alkaloid could been used as potential antimicrobial agent.

Three new phenazine metabolites, strepphenazine A-C (1-3), along with a known compound baraphenazine E 4 were isolated from the culture broth of a Streptomyces strain YIM PH20095. The structures were elucidated based on the spectral data. Compounds 1-4 showed different antifungal activity against Fusarium oxysporum, Plectosphaerella cucumerina, Alternaria panax, and Phoma herbarum, which caused root-rot disease of Panax notoginseng with minimal inhibitory concentrations (MICs) of 16-64 μg/mL; compared with compound 4, compounds 1-3 showed better antifungal activity against some of these pathogenic fungi with MICs of 16-32 μg/mL, while compound 4 showed antifungal activity against F. oxysporum, P. cucumerina, and A. panax with the same MICs of 64 μg/mL. Thus, strain YIM PH20095 provides new sources for the development of biological control agents to prevent the infection of pathogenic fungi of P. notoginseng.

Acyltransferase (AT)-less type I polyketide synthases (PKSs) produce complex natural products due to the presence of many unique tailoring enzymes. The 3-hydroxy-3-methylglutaryl coenzyme A synthases (HCSs) are responsible for β-alkylation of the growing polyketide intermediates in AT-less type I PKSs. In this study, we discovered a large group of HCSs, closely associated with the characterized and orphan AT-less type I PKSs through in silico genome mining, sequence and genome neighbourhood network analyses. Using HCS-based probes, the survey of 1207 in-house strains and 18 soil samples from different geographic locations revealed the vast diversity of HCS-containing AT-less type I PKSs. The presence of HCSs in many AT-less type I PKSs suggests their co-evolutionary relationship. This study provides a new probe to study the abundance and diversity of AT-less type I PKSs in the environment and microbial strain collections. Our study should inspire future efforts to discover new polyketide natural products from AT-less type I PKSs.

Lymphatic filariasis and onchocerciasis diseases caused by filarial parasite infections can lead to profound disability and affect millions of people worldwide. Standard mass drug administration campaigns require repetitive delivery of anthelmintics for years to temporarily block parasite transmission but do not cure infection because long-lived adult worms survive the treatment. Depletion of the endosymbiont Wolbachia, present in most filarial nematode species, results in death of adult worms and therefore represents a promising target for the treatment of filariasis. Here, we used a high-content imaging assay to screen the pure compounds collection of the natural products library at The Scripps Research Institute for anti- Wolbachia activity, leading to the identification of kirromycin B (1) as a lead candidate. Two additional congeners, kirromycin (2) and kirromycin C (3), were isolated and characterized from the same producing strain Streptomyces sp. CB00686. All three kirromycin congeners depleted Wolbachia in LDW1 Drosophila cells in vitro with half-maximal inhibitory concentrations (IC

Endophytic fungi play important roles for host's stress tolerance including invasion by pathogenic microbes. Small molecules are common weapons in the microbe-microbe interactions. Panax notoginseng is a widely used traditional Chinese medicinal plant and harbors many endophytes, some exert functions against pathogens. Here, we report six new compounds named myrothins A-F (1-6) produced by Myrothecium sp. BS-31, an endophyte isolated from P. notoginseng, and their antifungal activities against pathogenic fungi causing host root-rot disease. Their structures were elucidated with analysis of spectroscopic data including 1D and 2D NMR, HR-ESI-MS. Myrothins B (2) and E (5) showed the weak activity against Fusarium oxysporum and Phoma herbarum, and myrothins F (6) showed weak activity against F. oxysporum.

Actinomycete strain YIM PH20520, isolated from the rhizosphere soil sample of Panax notoginseng collected in Wenshang, Yunnan Province, China, exhibited antifungal activity against root-rot pathogens of the Panax notoginseng. The structures of bioactive molecules, isolated from the ethyl acetate extract of the fermentation broth of the strain, were identified as echinosporin (1) and 7-deoxyechinosporin (2) based on extensive spectroscopic analyses. 1 exhibited antifungal activity against four tested root-rot pathogens of Panax notoginseng include Fusarium oxysporum, Fusarium solani, Alternaria panax, and Phoma herbarum with the MIC value at 64, 64, 32, and 64 μg/mL, respectively. 2 exhibited antifungal activities against F. oxysporum, F. solani, A. panax, and P. herbarum with the MIC value at 128, 128, 64, and 128 μg/mL, respectively. Based on the phylogenetic analyses, the closest phylogenetic relative of strain YIM PH20520 is Amycolatopsis speibonae JS72T (97.69%), so strain YIM PH20520 was identified as Amycolatopsis strain. To the best of our knowledge, this is the first report of echinosporin antibiotics isolated from Amycolatopsis strain besides Streptomyces strain and their antifungal activity against four tested root-rot pathogens of the Panax notoginseng. The results provide a reliable evidence for the following related biosynthetic investigations on Amycolatopsis strain YIM PH20520 due to echinosporins antibiotics’ unique tricyclic acetal-lactone structures.

A high-content imaging assay was used to screen the fraction collection of the Natural Product Library at The Scripps Research Institute for inhibitors of Cryptosporidium parvum. A chemical investigation of one strain, Streptomyces sp. CB01388, resulted in the isolation of six herbicidins (1-6), one of which is new (herbicidin L, 1). Five of the six herbicidins (1-3, 5, 6) showed moderate inhibitory activity against C. parvum, with 1 and 6 comparable to the FDA-approved drug nitazoxanide, and 2-6 showed no toxicity to the host HCT-8 cells and human HEK293T and HepG2 cells. These findings highlight the herbicidin scaffold for anti- Cryptosporidium drug development.

Strain YIM PH21724T was isolated from the rhizosphere of Panax notoginseng. Phylogenetic analyses based on 16S rRNA gene sequences showed that the strain exhibits close phylogenetic relatedness to Nocardia kroppenstedtii N1286T (97.70%), Nocardia farcinica NCTC 11134T (97.67%) and Nocardia puris DSM 44599T (97.40%). The menaquinones were identified as MK-9 (H4), MK-8 (H4, ω-cyclo) and MK-8 (H4), and the major fatty acids (> 10%) were identified as C16:0, C18:1 ω9c and C18:0 10-methyl. The polar lipids were found to be composed of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol, phosphatidylinositol mannosides and an unidentified lipid. The G + C content of the genomic DNA was determined to be 67.01 mol%. The phenotypic, chemotaxonomic, phylogenetic and genomic results clearly show strain YIM PH21724T should be classified in the genus Nocardia and represents a novel species, for which the name Nocardia panacis sp. nov. is proposed. The type strain is YIM PH21724T (= DSM 105904T = KCTC 49030T = CCTCC AA 2017043T).

Two new phenazine metabolites, 6-hydroxyphenazine-1-carboxamide (1) and methyl 6-carbamoylphenazine-1-carboxylate (2), were isolated from a soil-derived Streptomyces diastaticus subsp. ardesiacus strain YIM PH20246, and their structures were elucidated by extensive spectroscopic data analysis. The antimicrobial activities of the isolates were assayed. Compound 1 showed moderate antifungal and antibacterial activities against Fusarium oxysporum (ATCC 7808), Fusarium solani (ATCC 36031) and Plectosphaerella cucumerina (local isolate), Staphylococcus aureus (ATCC 25923) and Staphylococcus albus (ATCC 10231), respectively. Compound 2 exhibited moderate antifungal and antibacterial activities against F. oxysporum, F. solani, and Phoma herbarum, S. aureus, S. albus, and Bacillus subtilis, respectively.

Two new N-benzoylamino acids, peniginseng A-B (1–2), and two new fatty acids, peniciginseng A-B (5–6), were isolated during the fermentation of Penicillium sp. YIM PH30003, an endophytic fungus associated with Panax notoginseng (Burk.) F.H. Chen. Their structures were assigned based on a combination of 1D and 2D NMR and mass spectral data. The N-benzoylamino acids (1–4) might share similar biosynthetic pathways with the rare siderophore pistillarin. Compounds 1–10 showed antifungal activities (MICs 16–128 μg/mL) against Fusarium solani, the pathogenic fungus of P. notoginseng.

The potent cytotoxicity and unique mode of action make the enediyne antitumor antibiotic C-1027 an exquisite drug candidate for anticancer chemotherapy. However, clinical development of C-1027 has been hampered by its low titer from the original producer Streptomyces globisporus C-1027. Here we report three new C-1027 alternative producers, Streptomyces sp. CB00657, CB02329, and CB03608, from The Scripps Research Institute actino-mycetes strain collection. Together with the previously disclosed Streptomyces sp. CB02366 strain, four C-1027 alternative producers with C-1027 titers of up to 11-fold higher than the original producer have been discovered. The five C-1027 producers, isolated from distant geographic locations, are distinct Streptomyces strains based on morphology and taxonomy. Pulsed-field gel electrophoresis and Southern analysis of the five C-1027 producers reveal that their C-1027 biosynthetic gene clusters (BGCs) are all located on giant plasmids of varying sizes. The high nucleotide sequence similarity among the five C-1027 BGCs implies that they most likely have evolved from a common ancestor.

Soil microbiota represents one of the ancient evolutionary origins of antibiotic resistance and has been increasingly recognized as a potentially vast unstudied reservoir of resistance genes with possibilities to exchange with pathogens. Tetracycline resistance is one of the most abundant antibiotic resistances that may transfer among clinical and commensal microorganisms. To investigate tetracycline resistance genes from soil bacteria in different habitats, we performed functional analysis of three metagenomic libraries derived from soil samples collected from Yunnan, Sichuan, and Tibet, respectively, in China. We found efflux transporter genes form all the libraries, including 21 major facilitator superfamily efflux pump genes and one multidrug and toxic compound extrusion (MATE) transporter gene. Interestingly, we also identified two tetracycline destructase genes, belonging to a newly described family of tetracycline-inactivating enzymes that scarcely observed in clinical pathogens, from the Tibet library. The inactivation activity of the putative enzyme was confirmed in vitro by biochemical analysis. Our results indicated that efflux pumps distributed predominantly across habitats. Meanwhile, the mechanism of enzymatic inactivation for tetracycline resistance should not be neglected and merits further investigation.

A novel endophytic actinobacterium, designated strain YIM 68236T, was isolated from healthy leaves of Camptotheca acuminata. and characterized by using a polyphasic approach. Cells of this strain occurred singly, in pairs or in tetrads. It grew at 10–45 °C, at pH 5.0–8.0 (optimum pH 7.0) and in the presence of 0–3 % (w/v) NaCl. The DNA G+C content was 71.6 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain YIM 68236T belongs to the genus Blastococcus . However, it differed from its closest relatives, Blastococcus aggregatus DSM 4725T, Blastococcus saxobsidens DSM 44509T and Blastococcus jejuensis DSM 19597T in many phenotypic characteristics. Moreover, the DNA–DNA relatedness values between the novel isolate and the three above-mentioned type strains were 49.0±1.6 %, 46.1±3.2 % and 39.8±1.5 %, respectively. Based on comparative analysis of physiological and chemotaxonomic data, strain YIM 68236T represents a novel species of the genus Blastococcus , for which the name Blastococcus endophyticus sp. nov. is proposed. The type strain is YIM 68236T ( = CCTCC AA 209045T = DSM 45413T = KCTC 19998T).

Since current antifungal drugs have not kept pace with the escalating medical demands of fungal infections, new, effective medications are required. However, antifungal drug discovery is hindered by the evolutionary similarity of mammalian and fungal cells, which results in fungal drug targets having human homologs and drug non-selectivity. The group III hybrid histidine kinases (HHKs) are an attractive drug target since they are conserved in fungi and absent in mammals. We used a Saccharomyces cerevisiae reporter strain that conditionally expresses HHK to establish a high-throughput bioassay to screen microbial extracts natural products for antifungals. We identifi ed macrotetrolides, a group of related ionophores thought to exhibit restricted antifungal activity. In addition to confi rming the use of this bioassay for the discovery of antifungal natural products, we demonstrated broader, more potent fungistatic activity of the macrotetrolides against multiple Candida spp., Cryptococcus spp., and Candida albicans in biofi lms. Macrotetrolides were also active in an animal model of C. albicans biofi lm, but were found to have inconsistent activity against fl uconazole-resistant C. albicans , with most isolates resistant to this natural product. The macrotetrolides do not directly target HHKs, but their selective activity against S. cerevisiae grown in galactose (regardless of Drk1 expression) revealed potential new insight into the role of ion transport in the mode of action of these promising antifungal compounds. Thus, this simple, high-throughput bioassay permitted us to screen microbial extracts, identify natural products as antifungal drugs, and expand our understanding of the activity of macrotetrolides.

The enediyne family of natural products has had a profound impact on modern chemistry, biology, and medicine, and yet only 11 enediynes have been structurally characterized to date. Here we report a genome survey of 3,400 actinomycetes, identifying 81 strains that harbor genes encoding the enediyne polyketide synthase cassettes that could be grouped into 28 distinct clades based on phylogenetic analysis. Genome sequencing of 31 representative strains confirmed that each clade harbors a distinct enediyne biosynthetic gene cluster. A genome neighborhood network allows prediction of new structural features and biosynthetic insights that could be exploited for enediyne discovery. We confirmed one clade as new C-1027 producers, with a significantly higher C-1027 titer than the original producer, and discovered a new family of enediyne natural products, the tiancimycins (TNMs), that exhibit potent cytotoxicity against a broad spectrum of cancer cell lines. Our results demonstrate the feasibility of rapid discovery of new enediynes from a large strain collection., IMPORTANCE Recent advances in microbial genomics clearly revealed that the biosynthetic potential of soil actinomycetes to produce enediynes is underappreciated. A great challenge is to develop innovative methods to discover new enediynes and produce them in sufficient quantities for chemical, biological, and clinical investigations. This work demonstrated the feasibility of rapid discovery of new enediynes from a large strain collection. The new C-1027 producers, with a significantly higher C-1027 titer than the original producer, will impact the practical supply of this important drug lead. The TNMs, with their extremely potent cytotoxicity against various cancer cells and their rapid and complete cancer cell killing characteristics, in comparison with the payloads used in FDA-approved antibody-drug conjugates (ADCs), are poised to be exploited as payload candidates for the next generation of anticancer ADCs. Follow-up studies on the other identified hits promise the discovery of new enediynes, radically expanding the chemical space for the enediyne family.

Two new metabolites named koninginins R-S (1–2) were isolated from the culture of Trichoderma koningiopsis YIM PH30002. Their chemical structures were elucidated by the extensive spectroscopic analysis. These isolated compounds showed certain antifungal activities against phytopathogens, Fusarium flocciferum and Fusarium oxysporum.

A novel endophytic actinomycete, designated strain YIM 68255T, was isolated from healthy leaves of Camptotheca acuminata Decne. collected in Yunnan province, south-west China and characterized by using a polyphasic approach. The strain formed well-developed substrate mycelium, but no aerial mycelium. It grew at 10–45 °C, at pH 5–10 (optimum pH 7) and in the presence of 0–3 % (w/v) NaCl. The DNA G+C content was 73.0 mol%. Phylogenetic analyses showed that strain YIM 68255T belonged to the genus Plantactinospora . However, it exhibited some differences from Plantactinospora mayteni YIM 61359T and the level of DNA–DNA relatedness was 42.7±1.3 %. Based on comparative analysis of physiological and chemotaxonomic data, it is proposed that strain YIM 68255T represents a novel species of the genus Plantactinospora , Plantactinospora endophytica sp. nov., with strain YIM 68255T ( = DSM 45387T = CCTCC AA 209047T) as the type strain. In addition, it is also proposed that Actinaurispora siamensis Thawai et al. 2010 be transferred to the genus Plantactinospora as Plantactinospora siamensis comb. nov. [type strain CM2-8T ( = JCM 15677T = BCC 34762T)] based on chemotaxonomic characteristics and phylogenetic analysis. Emended descriptions of the genus Plantactinospora and Plantactinospora mayteni are also provided.

A Gram-positive, non-motile actinobacterium, designated YIM 65754T, was isolated from the stem of Artemisia annua L., collected from Yunnan province, south-west China. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain YIM 65754T comprised an evolutionary lineage within the genus Rhodococcus . The isolate clustered with Rhodococcus pyridinivorans PDB9T, Rhodococcus gordoniae W 4937T and Rhodococcus rhodochrous DSM 43241T, with which it shared 98.4, 97.9 and 97.8 % 16S rRNA gene sequence similarities, respectively. However, DNA–DNA relatedness demonstrated that strain YIM 65754T was distinct from its closest phylogenetic neighbours. The cell-wall peptidoglycan contained meso-diaminopimelic acid, arabinose, galactose, mannose and glucose (cell-wall chemotype IV). The major menaquinone was MK-8(H2) and the predominant fatty acids were C16 : 0 (27.83 %), iso-C15 : 0 2-OH and/or C16 : 1ω7c (20.21 %) and 10-methyl C18 : 0 (17.50 %). The DNA G+C content was 66.2 mol%. On the basis of phenotypic, chemotaxonomic and phylogenetic evidence, the isolate represents a novel species of the genus Rhodococcus , for which the name Rhodococcus artemisiae sp. nov. is proposed; the type strain is YIM 65754T ( = CCTCC AA 209042T = DSM 45380T).

Cycloheximide and congeners as inhibitors of eukaryotic protein synthesis from endophytic actinomycetes Streptomyces sps. YIM56132 and YIM56141

Fourteen metabolites with various structure types were isolated from endophytic Chaetomium globosum. Five compounds were separated from genus Chaetomium for the first time. Some compounds exhibited remarkable inhibition against phytopathogenic fungi causing root rot of Panax notoginseng. Compounds 1–5 had significant DPPH-free radical-scavenging activity. Compounds 3 and 5 indicated significant inhibitions against the acetylcholinesterase (AChE). From preliminary structure–activity relationship, it was found that the oxygenic five-membered ring of 3 and 5 was crucial in the anti-AChE activity. These structures provide new templates for the potential treatment and management of plant diseases and Alzheimer disease.

A novel endophytic actinobacterium, designated strain YIM 64602T, was isolated from healthy stems of Tripterygium wilfordii. It grew at 15–40 °C, pH 6.0–9.0 and in the presence of 0–3 % (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequence showed that strain YIM 64602T belongs to the genus Stackebrandtia . Whole-cell hydrolysates of strain YIM 64602T contained the amino acid meso-diaminopimelic acid with the sugars mannose, rhamnose and glucose, and a trace of ribose. The major polar lipids were diphosphatidylglycerol, phosphatidylmethylethanolamine and phosphatidylethanolamine. MK-10(H6), MK-10(H4) and MK-11(H4) were the predominant components in the quinone system. The fatty-acid pattern was mainly composed of the saturated branched-chain acids iso-C16 : 0, anteiso-C17 : 0, iso-C15 : 0 and iso-C17 : 0. The DNA G+C content was 72.4 mol%. 16S rRNA gene sequence analysis showed the highest pairwise sequence identity (96.0–98.5 %) with the members of the genus Stackebrandtia . Strain YIM 64602T displayed a DNA–DNA relatedness of 43.9±0.4 % with the type strain Stackebrandtia albiflava YIM 45751T. Based on evidence from this polyphasic study, strain YIM 64602T ( = BCRC 16954T = DSM 45928T) is considered to represent a novel species of the genus Stackebrandtia , for which the name Stackebrandtia endophytica is proposed.

Many thermophilic actinomycetes were isolated from samples collected from a hot-spring, lake and soil in Yunnan, China. Chemical and molecular classification of four selected strains of thermophilic Streptomyces with an upper limited growth temperature of 65-68 degrees C and autolytic characteristics was carried out. A new species, Streptomyces thermogriseus sp. nov. is described. The type strain is Y-14046T (= CCTCC AA97014T).

Eight anthraquinones (1–8), three xanthones (11–13) and two phenols (9–10) were isolated from Aspergillus sp. associated with Panax notoginseng, and their structures were determined as ziganein-1-methyl ether (1), 8-O-methylchrysophanol (2), averythrin (3), averufin (4), 8-O-methyl averufin (5), versicolorin B (6), averantin (7), methyl-averantin (8), arugosin C (9), diorcinol (10), sterigmatocystin (11), demethylsterigmatocystin (12) and dihydrosterigmatocystin (13) by spectroscopic analyses. Compounds 1, 2 and 5 were the novel isolates from genus Aspergillus. Compounds 3, 6 and 7 exhibited antifungal activity against Fusariumsolani, pathogenic fungus of P. notoginseng, with minimum inhibitory concentrations (MICs) of 16–32 μg/mL, and compounds 1, 3, 4, 7 and 9 showed antibacterial activity against Bacillussubtilis with MICs of 64–128 μg/mL, 16–32 μg/mL, 8–16 μg/mL, 16–32 μg/mL and 64–128 μg/mL, respectively. The metabolites showed the potential value in the research of antifungal agents, especially in searching for a biocontrol of diseases of P. notoginseng. The preliminary structure–activity relationships have been discussed for some of the compounds.

A novel endophytic actinobacterium, designated strain YIM 67072T, was isolated from healthy roots of Dysophylla stellata (Lour.) Benth. Cells of this aerobic, cream–yellow-coloured strain occurred singly, in pairs or in tetrads, were Gram-stain-positive and ovoid- to spherical-shaped. Strain YIM 67072T grew at 4–45 °C, pH 5.0–10.0 and in the presence of 0–7 % (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain YIM 67072T belonged to the genus Rothia . The isolate contained MK-7 as the major component of the quinone system. The peptidoglycan type was A3α. The polar lipid profile consisted predominantly of diphosphatidylglycerol and glycolipids. The major fatty acids were anteiso-C15 : 0, iso-C15 : 0, anteiso-C17 : 0 and iso-C16 : 0. The DNA G+C content was 53.2 mol%. However, strain YIM 67072T differed from its closest relatives Rothia nasimurium CCUG 35957T (98.5 % 16S rRNA gene sequence similarity), Rothia amarae JCM 11375T (97.6 %) and Rothia terrae L-143T (97.3 %) in many phenotypic characteristics. Moreover, the levels of DNA–DNA relatedness between the novel isolate and the three above-mentioned type strains were 28.7±1.3 %, 36.5±1.2 %, 46.8±1.5 %, respectively. Based on comparative analysis of physiological and chemotaxonomic data, strain YIM 67072T represents a novel species of the genus Rothia , for which the name Rothia endophytica sp. nov. is proposed. The type strain is YIM 67072T ( = DSM 26247T = JCM 18541T).

Endophytic actinobacteria colonize internal tissues of their host plants and are considered as a rich and reliable source of diverse species and functional microorganisms. In this study, endophytic actinobacterial strain YIM 63111 was isolated from surface-sterilized tissue of the medicinal plant Artemisia annua. We identified strain YIM 63111 as a member of the genus Pseudonocardia. A. annua seedlings grown under both sterile and greenhouse conditions were inoculated with strain YIM 63111. The growth of A. annua seedlings was strongly reduced when YIM 63111 was inoculated at higher concentrations under sterile conditions. However, no growth inhibition was observed when A. annua was grown under greenhouse conditions. Using an enhanced green fluorescent protein (EGFP) expressing YIM 63111 strain, we also observed the endophytic colonization of A. annua seedling using confocal laser-scanning microscopy. The transcription levels of the key genes involved in artemisinin biosynthesis were investigated using real time RT-PCR, revealing that cytochrome P450 monooxygenase (CYP71AV1) and cytochrome P450 oxidoreductase (CPR) expression were up-regulated in A. annua upon inoculation with strain YIM 63111 under certain conditions. The up-regulation of these genes was associated with the increased accumulation of artemisinin. These results suggest that endophytic actinobacteria effectively stimulate certain plant defense responses. Our data also demonstrate the use of Pseudonocardia sp. strain YIM 63111 as a promising means to enhance artemisinin production in plants.

Endophytic actinobacteria isolated from Artemisia annua were characterized and evaluated for their bioactivities. A total of 228 isolates representing at least 19 different genera of actinobacteria were obtained and several of them seemed to be novel taxa. An evaluation of antimicrobial activity showed that more isolates possessed activity towards plant pathogens than activity against other pathogenic bacteria or yeasts. High frequencies of PCR amplification were obtained for type I polyketide synthases (PKS-I, 21.1%), type II polyketide synthases (PKS-II, 45.2%) and nonribosomal peptide synthetases (NRPS, 32.5%). The results of herbicidal activity screening indicated that 19 out of 117 samples of fermentation broths completely inhibited the germination of Echinochloa crusgalli. This study indicated that endophytic actinobacteria associated with A. annua are abundant and have potentially beneficial and diverse bioactivities which should be pursued for their biotechnical promise.

isolation, structure determination and cytotoxicity of two new bafilomycins, 9-hydroxybafilomycin D (Ia) and 29-hydroxybafilomycin D (Ib), together with nine known bafilomycins

A novel xylan-degrading actinomycete, strain YIM 61515T, was isolated from surface-sterilized leaves of the medicinal plant Maytenus austroyunnanensis. Cells were Gram-positive and non-spore-forming, produced primary branches and formed white to yellowish white colonies on the media tested. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain YIM 61515T was most similar to Promicromonospora aerolata V54AT and Promicromonospora vindobonensis V45T (99.4 and 99.1 % sequence similarity, respectively). The isolate formed a separate lineage in a cluster containing P. aerolata V54AT. 16S rRNA gene sequence similarity between the isolate and other members of the genus Promicromonospora ranged from 96.3 to 98.4 %. Chemotaxonomic data, including major menaquinones, fatty acid compositions and polar lipid profiles, supported the placement of strain YIM 61515T in the genus Promicromonospora. DNA–DNA relatedness, physiological and biochemical data showed that strain YIM 61515T could be distinguished from members of all known species of the genus Promicromonospora and therefore represented a novel species. The name Promicromonospora xylanilytica sp. nov. is proposed, with YIM 61515T ( = DSM 21603T = CCTCC AA 208046T) as type strain.

During the course of our research on new actinobacterial sources, a novel actinomycete strain YIM 63101(T) was isolated from the surface-sterilized roots of Artemisia annua L. collected from Xishuangbanna, Yunnan province, south-west China and characterized by using a polyphasic approach. The strain formed well-differentiated aerial and substrate mycelia. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain YIM 63101(T) belongs to the genus Pseudonocardia, with highest similarity to "Pseudonocardia artemisiae YIM 63587(T)" (99.4%). Sequence similarities between strain YIM 63101(T) and the other Pseudonocardia species ranged from 97.0 (Pseudonocardia saturnea IMSNU 20052(T)) to 94.0% (Pseudonocardia compacta IMSNU 20111(T)). The chemotaxonomic characteristics, such as cell wall diaminopimelic acid, whole-cell sugars, fatty acid components and the major menaquinones suggested that the organism belonged to the genus Pseudonocardia. The G + C content of the genomic DNA was 69.4 mol%. Based on comparative analysis of physiological, biochemical and chemotaxonomic data, including low DNA-DNA hybridization results, it is proposed that strain YIM 63101(T) represents a novel species of the genus Pseudonocardia, named Pseudonocardia bannaensis sp. nov. The type strain is YIM 63101(T) (= CCTCC AA 208077 (T) = DSM 45300(T)).

A novel actinomycete strain, designated YIM 63587T, was isolated from surface-sterilized roots of Artemisia annua L. collected from Yunnan province, south-west China. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain YIM 63587T was affiliated to the genus Pseudonocardia. 16S rRNA gene sequence similarities between strain YIM 63587T and type strains of species of the genus Pseudonocardia were 96.6–93.8 %. The diagnostic cell-wall diamino acid in the peptidoglycan layer of strain YIM 63587T was meso-diaminopimelic acid and the whole-cell sugars were arabinose, galactose, mannose and ribose. The predominant menaquinone was MK-8(H4) (97.7 %). The phospholipids were diphosphatidylglycerol, phosphatidylmethylethanolamine, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, phosphatidylinositol mannosides, phosphatidylinositol and an unknown phospholipid. The major cellular fatty acids (>5 %) were iso-C16 : 0 (44.7 %), iso-C14 : 0 (10.3 %), iso-C16 : 1 H (9.8 %) and iso-C15 : 0 (7.7 %). The G+C content of the genomic DNA was 68.2 mol%. On the basis of phylogenetic, physiological and chemotaxonomic data, strain YIM 63587T represents a novel species of the genus Pseudonocardia, for which the name Pseudonocardia artemisiae sp. nov. is proposed. The type strain is YIM 63587T ( = DSM 45313T = CCTCC AA 208081T).

Four new fungal polyketides named koninginins N-Q (1–4), together with four known analogues (5–8), were isolated from the endophytic fungus Trichoderma koningiopsis YIM PH30002 harbored in Panax notoginseng. Their structures were determined on the basis of spectral data interpretation. These compounds were evaluated for their antifungal activity, nitric oxide inhibition, and anticoagulant activity. Graphical Abstract Electronic supplementary material The online version of this article (doi:10.1007/s13659-015-0085-z) contains supplementary material, which is available to authorized users.