Wensheng Xiang

Genome Sequence of the Milbemycin-Producing Bacterium Streptomyces bingchenggensis

Streptomyces bingchenggensis is a soil-dwelling bacterium producing the commercially important anthelmintic macrolide milbemycins. Besides milbemycins, the insecticidal polyether antibiotic nanchangmycin and some other antibiotics have also been isolated from this strain. Here we report the complete genome sequence of S. bingchenggensis. The availability of the genome sequence of S. bingchenggensis should enable us to understand the biosynthesis of these structurally intricate antibiotics better and facilitate rational improvement of this strain to increase their titers.

Nonomuraea solani sp. nov., an actinomycete isolated from eggplant root (Solanum melongena L.)

A novel actinomycete, designated strain NEAU-Z6(T), was isolated from eggplant (Solanum melongena L.) root. Phylogenetic analysis based on the 16S rRNA gene sequence showed that strain NEAU-Z6(T) belonged to the genus Nonomuraea, with highest sequence similarity to Nonomuraea monospora PT 708(T) (98.83 %), Nonomuraea rosea GW 12687(T) (98.55 %) and Nonomuraea rhizophila YIM 67092(T) (98.02 %). Sequence similarities between strain NEAU-Z6(T) and other species of the genus Nonomuraea ranged from 97.94 % (Nonomuraea candida HMC10(T)) to 96.30 % (Nonomuraea wenchangensis 210417(T)). Key morphological, physiological and chemotaxonomic characteristics of strain NEAU-Z6(T) were congruent with the description of the genus Nonomuraea. The G+C content of the genomic DNA was 64.51 mol%. DNA-DNA relatedness and comparative analysis of physiological, biochemical and chemotaxonomic data allowed genotypic and phenotypic differentiation of strain NEAU-Z6(T) from closely related species. Thus, strain NEAU-Z6(T) represents a novel species of the genus Nonomuraea, for which the name Nonomuraea solani sp. nov. is proposed. The type strain is NEAU-Z6(T) ( = CGMCC 4.7037(T) = DSM 45729(T)).

A new prenylated indole derivative from endophytic actinobacteria Streptomyces sp. neau-D50

A new prenylated indole derivative 3-acetonylidene-7-prenylindolin-2-one (1) was isolated from the endophytic actinobacterium Streptomyces sp. neau-D50, together with four known hybrid isoprenoids, 7-isoprenylindole-3-carboxylic acid (2), 3-cyanomethyl-6-prenylindole (3), 6-isoprenylindole-3-carboxylic acid (4) and 7,4′-dihydroxy-5-methoxy-8-(γ,γ-dimethylallyl)-flavanone (5). The structures of these compounds were elucidated on the basis of extensive spectroscopic analysis and comparison with data from the literature. Compounds 1 and 2 demonstrated strong cytotoxic activities against human lung adenocarcinoma cell line A549 with an IC50 of 3.3 and 5.1 μg mL− 1, respectively, which are comparable to that of the positive control doxorubicin (4.2 μg mL− 1). Furthermore, compounds 1–4 exhibited potent antifungal activity against phytopathogenic fungi Colletotrichum orbiculare, Phytophthora capsici, Corynespora cassiicola and Fusarium oxysporum.

Cycloheximide and actiphenol production in Streptomyces sp. YIM56141 governed by single biosynthetic machinery featuring an acyltransferase-less type I polyketide synthase.

Cycloheximide (1) and actiphenol (2) have been isolated from numerous Streptomyces species. Cloning, sequencing, and characterization of a gene cluster from Streptomyces sp. YIM65141 now establish that 1 and 2 production is governed by single biosynthetic machinery. Biosynthesis of 1 features an acyltransferase-less type I polyketide synthase to construct its carbon backbone but may proceed via 2 as a key intermediate, invoking a provocative reduction of a phenol to a cyclohexanone moiety in natural product biosynthesis.

A novel macrolide compound from Streptomyces bingchenggensis: fermentation, isolation, structure elucidation and biological properties

A novel macrolide compound from Streptomyces bingchenggensis : fermentation, isolation, structure elucidation and biological properties

Isolation and Identification of Novel Macrocyclic Lactones from Streptomyces avermitilis NEAU1069 with Acaricidal and Nematocidal Activity

Bioactivity-guided fractionation of Streptomyces avermitilis NEAU1069 fermentation broth was used to isolate and determine the chemical identity of bioactive constituents with acaricidal and nemotocidal activity. The structures of novel compounds 1 and 2 were determined on the basis of spectroscopic analysis, including 1D and 2D NMR as well as HRESI-MS, ESI-MS of spectrometry analysis, UV and IR spectroscopic analyses, and comparison with data from the literature. The acaricidal activities of the isolated compounds against adult mites and mite eggs were evaluated by mortality and unhatched eggs. The nematocidal activity of the isolated compounds against Caenorhabditis elegans was calculated according to the immobilized rates against the total number of tested nematodes. The results indicated that compounds 1 and 2 exhibited potent acaricidal activity against adult mites, with a mortality of >90% at a concentration of 30 microg/mL. However, compounds 1 and 2 showed only weak acaricidal activity against mite eggs, with unhatched mite egg rates of <60% at a concentration of 100 microg/mL. Compound 2, a hydroxylated derivative at C-23 of 1, possessed a high nematocidal activity against C. elegans, with an immobility of >90% at a concentration of 10 microg/mL. These results demonstrate that compounds 1 and 2, especially compound 2, have potential as pesticides with acaricidal and nematocidal activity.

Micromonospora zeae sp. nov., a novel endophytic actinomycete isolated from corn root (Zea mays L.).

A novel actinomycete, designated strain NEAU-gq9T, was isolated from corn root (Zea mays L.) and characterized using a polyphasic approach. The organism was found to have morphological and chemotaxonomic characteristics typical of the genus Micromonospora. On the basis of 16S rRNA gene sequence similarity studies, strain NEAU-gq9T was most closely related to Micromonospora zamorensis CR38T (99.3%), Micromonospora jinlongensis NEAU-GRX11T (99.2%), Micromonospora saelicesensis Lupac 09T (99.2%), Micromonospora chokoriensis 2-19(6)T (98.9%), Micromonospora coxensis 2-30-b(28)T (98.6%) and Micromonospora lupini Lupac 14NT (98.5%). Phylogenetic analysis based on the 16S rRNA gene and gyrB gene demonstrated that strain NEAU-gq9T is a member of the genus Micromonospora and supported the closest phylogenetic relationship to M. zamorensis CR38T, M. jinlongensis NEAU-GRX11T, M. saelicesensis Lupac 09T, M. chokoriensis 2-19(6)T and M. lupini Lupac 14NT. A combination of DNA–DNA hybridization, morphological and physiological characteristics indicated that the novel strain could be readily distinguished from the closest phylogenetic relatives. Therefore, it is proposed that strain NEAU-gq9T represents a novel species of the genus Micromonospora, for which the name Micromonospora zeae sp. nov. is proposed. The type strain is NEAU-gq9T (=CGMCC 4.7092T=DSM 45882T).

Streptomyces harbinensis sp. nov., an endophytic, ikarugamycin-producing actinomycete isolated from soybean root [Glycine max (L.) Merr].

A novel ikarugamycin-producing actinomycete, designated strain NEAU-Da3(T), was isolated from soybean root [Glycine max (L.) Merr.] and characterized using a polyphasic approach. 16S rRNA gene sequence similarity studies showed that strain NEAU-Da3(T) belonged to the genus Streptomyces, and was most closely related to Streptomyces carpaticus NRRL B-16359(T) (99.5 %), Streptomyces cheonanensis VC-A46(T) (99.3 %) and Streptomyces xiamenensis MCCC 1A01550(T) (97.2 %); similarities to other type strains of species of the genus Streptomyces were lower than 97.1 %. The maximum-likelihood phylogenetic tree based on 16S rRNA gene sequences showed that the isolate formed a distinct phyletic line with S. carpaticus NRRL B-16359(T), S. cheonanensis VC-A46(T) and S. xiamenensis MCCC 1A01550(T). This branching pattern was also supported by the tree reconstructed with the neighbour-joining method. A comparative study between strain NEAU-Da3(T) and the type strains of the closest related species of the genus Streptomyces revealed that it differed from them in morphological, physiological and biochemical characteristics. Therefore, it is proposed that strain NEAU-Da3(T) represents a novel species of the genus Streptomyces, for which the name Streptomyces harbinensis sp. nov. is proposed. The type strain is NEAU-Da3(T) ( = CGMCC 4.7047(T) = DSM 42076(T)).

Streptomyces zhaozhouensis sp. nov., an actinomycete isolated from candelabra aloe (Aloe arborescens Mill).

A novel endophytic actinomycete, designated strain NEAU-LZS-5(T), was isolated from the leaf of candelabra aloe (Aloe arborescens Mill) and characterized using a polyphasic approach. Analysis of the 16S rRNA gene sequence showed that strain NEAU-LZS-5(T) belongs to the genus Streptomyces and exhibited 99.51 and 97.37 % similarity to Streptomyces sedi YIM 65188(T) and Streptomyces specialis GW41-1564(T), respectively, whereas low similarity values (<97 %) distinguished strain NEAU-LZS-5(T) from all other species of the genus Streptomyces with validly published names. Two tree-making algorithms also supported the position that strain NEAU-LZS-5(T) formed a distinct clade with Streptomyces sedi YIM 65188(T) and Streptomyces specialis GW41-1564(T). However, levels of DNA-DNA relatedness between strain NEAU-LZS-5(T) and Streptomyces sedi YIM 65188(T) and Streptomyces specialis GW41-1564(T) were 45.59 and 31.90 %, respectively. A comparative study between strain NEAU-LZS-5(T) and the type strains of closest related species of the genus Streptomyces revealed that it differed from them in morphological, physiological and biochemical characteristics. Therefore, strain NEAU-LZS-5(T) represents a novel species of the genus Streptomyces, for which the name Streptomyces zhaozhouensis sp. nov. is proposed. The type strain is NEAU-LZS-5(T) ( = CGMCC 4.7095(T) = DSM 42101(T)).

Xiangella phaseoli gen. nov., sp. nov., a member of the family Micromonosporaceae

A novel endophytic actinomycete, designated strain NEAU-J5(T) was isolated from roots of snap bean (Phaseolus vulgaris L.). Comparative analysis of the 16S rRNA gene sequence indicated that NEAU-J5(T) is phylogenetically related to members of the family Micromonosporaceae. The whole-cell sugars were galactose, mannose and glucose. The predominant menaquinones were MK-9(H4) and MK-9(H6). The major fatty acids were C16:0, C18:0, C17:1ω7c, iso-C15:0 and C17:0. The phospholipids were phosphatidylmethylethanolamine, phosphatidylethanolamine, phosphatidylcholine, phosphatidylinositol and phosphatidylinositol mannoside. The DNA G+C content was 72.2 mol%. On the basis of the morphological and chemotaxonomic characteristics, phylogenetic analysis and characteristic patterns of 16S rRNA gene signature nucleotides, strain NEAU-J5(T) represents a novel species of a new genus within the family Micromonosporaceae, for which the name Xiangella phaseoli gen. nov., sp. nov. is proposed. The type strain of Xiangella phaseoli is strain NEAU-J5(T) (=CGMCC 4.7038(T)=DSM 45730(T)).