Xiu Chen

Violapyrones A–G, α-Pyrone Derivatives from Streptomyces violascens Isolated from Hylobates hoolock Feces

Seven new 3,4,6-trisubstituted α-pyrone derivatives, violapyrones A-G (1-7), were isolated from Streptomyces violascens obtained from Hylobates hoolock feces. Their structures were elucidated on the basis of detailed spectroscopic analysis. The antimicrobial activities of 1-7 were evaluated against Gram-positive and Gram-negative bacteria and against fungi. Compounds 1-3 showed moderate antibacterial activities against Bacillus subtilis and Staphylococcus aureus with MIC values of 4-32 μg/mL.

Bafilomycins and Odoriferous Sesquiterpenoids from Streptomyces albolongus Isolated from Elephas maximus Feces

From a fermentation broth of Streptomyces albolongus obtained from Elephas maximus feces, nine bafilomycins (1-9) and seven odoriferous sesquiterpenoids (10-16) were isolated. The structures of the new compounds, including three bafilomycins, 19-methoxybafilomycin C1 amide (1), 21-deoxybafilomycin A1 (2), and 21-deoxybafilomycin A2 (3), and two sesquiterpenoid degradation products, (1β,4β,4aβ,8aα)-4,8a-dimethyloctahydronaphthalene-1,4a(2H)-diol (10) and (1β,4β,4aβ,7α,8aα)-4,8a-dimethyloctahydronaphthalene-1,4a,7(2H)-triol (11), were elucidated by comprehensive spectroscopic data analysis. The cytotoxicity activity against four human cancer cell lines and antimicrobial activities against a panel of bacteria and fungi of all compounds isolated were evaluated. Compounds 1, 7, and 8 were cytotoxic, with IC50 values ranging from 0.54 to 5.02 μM. Compounds 2, 7, 8, and 10 showed strong antifungal activity against Candida parapsilosis, with MIC values of 3.13, 1.56, 1.56, and 3.13 μg/mL respectively.

Halopolyspora alba gen. nov., sp. nov., isolated from sediment.

A novel halophilic, filamentous actinomycete, designated strain AFM 10251(T), was isolated from a sediment sample collected from the Dead Sea, Israel. The isolate grew with 10-35% multi-salts, and did not grow without NaCl or MgCl2. The isolate formed a white aerial mycelium, and long chains of arthrospores with more than 10 spores per chain. The spores were spherical or oval with warty surfaces, and sterile mycelium was present between individual spores. The isolate contained meso-diaminopimelic acid and a small proportion of LL-diaminopimelic acid as cell-wall diamino acids, and galactose and arabinose as whole-cell sugars. The major menaquinone was MK-9(H4). The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol and three unknown phospholipids. Major fatty acids were iso-C(16 : 0), iso-C(17 : 0), iso-C(15 : 0) and anteiso-C(17 : 0). The DNA G+C content of strain AFM 10251(T) was 66.7 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain AFM 10251(T) and the genus Actinopolyspora formed a distinct lineage. Analysis of the secondary structures of variable areas of the 16S rRNA gene showed that strain AFM 10251(T) was different from all recognized species of the genus Actinopolyspora and members of the family Pseudonocardiaceae. Analysis of the signature nucleotides of the 16S rRNA gene showed that strain AFM 10251(T) and Actinopolyspora halophila formed a single group, but with base pair differences at positions 127 : 234 and 183 : 194. On the basis of analysis of chemical and molecular characteristics, strain AFM 10251(T) is considered to represent a novel species of a new genus in the family Actinopolysporaceae, for which the name Halopolyspora alba gen. nov., sp. nov. is proposed. The type strain of Halopolyspora alba is AFM 10251(T) ( = DSM 45976(T) = CGMCC 4.7114(T)).

Structure elucidation of four prenylindole derivatives from Streptomyces sp. isolated from Ailuropoda melanoleuca feces

Four new prenylindole derivatives, (R)‐6‐(2,3‐dihydroxy‐3‐methylbutyl)indole (1), (R)‐6‐(2,3‐dihydroxy‐3‐methylbutyl)indolin‐2‐one (2), and an unseparated mixture of (Z)‐6‐(4‐hydroxy‐3‐methylbut‐2‐en‐1‐yl)indolin‐2‐one (3a) and (E)‐6‐(4‐hydroxy‐3‐methylbut‐2‐en‐1‐yl)indolin‐2‐one (3b) with a ratio of 3 : 2, were isolated from the culture broth of a streptomycete isolated from Ailuropoda melanoleuca feces. Their structures were elucidated on the basis of 1D and 2D NMR spectroscopic techniques. The absolute configuration of 1 was determined by Moshers method. Copyright

Janibacter indicus sp. nov., isolated from hydrothermal sediment of the Indian Ocean.

A Gram-staining-positive, aerobic and non-motile strain, 0704P10-1(T), was isolated from hydrothermal sediment of the Indian Ocean. Phylogenetic, phenotypic and chemotaxonomic data for the organism supported that it belonged to the genus Janibacter. Strain 0704P10-1(T) showed 97.2-98.7% 16S rRNA gene sequence similarities to the type strains of recognized members of the genus Janibacter. It contained meso-diaminopimelic acid as the diagnostic diamino acid in the cell wall. MK-8(H4) was the only menaquinone detected. The major fatty acids were iso-C16 : 0, C17 : 1ω8c and 10-methyl C17 : 0. Meanwhile, the results of DNA-DNA hybridization studies and other physiological and biochemical tests allowed the genotypic and phenotypic differentiation of strain 0704P10-1(T) from closely related species. Thus, strain 0704P10-1(T) represents a novel species of the genus Janibacter, for which the name Janibacter indicus sp. nov. is proposed. The type strain is 0704P10-1(T) ( = LMG 27493(T) = CGMCC 1.12511(T)).

New anti-inflammatory metabolites produced by Streptomyces violaceoruber isolated from Equus burchelli feces

Three new metabolites (2–4), together with one known compound, GTRI-02, (1) were isolated from a fermentation broth of Streptomyces violaceoruber derived from Equus burchelli feces. The structures of the new compounds 2–4 were established using comprehensive NMR spectroscopic data analysis as well as UV, IR and MS data. The anti-inflammatory activity of compounds 1–4 was tested by examining their ability to inhibit nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophage cells. Compound 2 showed a moderate inhibition of NO production with IC50 value of 51.2 μm.

Allokutzneria multivorans sp nov., an actinomycete isolated from soil

An actinomycete with well-branched mycelia, designated strain YIM 120521(T), was isolated from soil collected from the banks of the Nujiang River, Yunnan Province, south-west China. Both aerial and substrate mycelia were white and non-pigmented. Growth was observed at 4-40 °C (optimum 28 °C), pH 6.0-9.0 (optimum 7.0) and in 0-4 % (w/v) NaCl (optimum 0 %). Analysis of the 16S rRNA gene sequence revealed that strain YIM 120521(T) belongs to the genus Allokutzneria with the highest sequence similarity to Allokutzneria albata DSM 44149(T) (98.4 %). However, the mean DNA-DNA relatedness value between the two strains was below 70 %. Chemotaxonomic characteristics supported the inclusion of strain YIM 120521(T) in the genus Allokutzneria, with rhamnose, arabinose, glucose, galactose and mannose as the whole-cell sugars, meso-diaminopimelic acid as the cell-wall diamino acid and MK-9(H4) as the predominant menaquinone. On the basis of physiological, biochemical and chemotaxonomic characteristics, strain YIM 120521(T) is considered to represent a novel species of the genus Allokutzneria, for which the name Allokutzneria multivorans sp. nov. is proposed. The type strain is YIM 120521(T) ( = JCM 17342(T) = DSM 45532(T)).

Effect of borrelidin on hepatocellular carcinoma cells in vitro and in vivo

Hepatocellular carcinoma (HCC) is the most common type of liver cancer with high prevalence and mortality. Borrelidin, produced by several actinomycete bacteria of Streptomycin sp. exhibited diversiform activities including anti-bacterial, anti-viral, anti-angiogenic, and anti-tumor. However, the effect of borrelidin on HCC cells has not been characterized. The present study demonstrated borrelidin exhibited great potential to inhibit the growth of HCC cells, HepG2 and SMMC7721 in vitro. Western blot and real-time qPCR analysis revealed that borrelidin decreased the expressions of cyclin D1, cyclin D3, cyclin E1, CDK2, CDK4, and CDK6 and increased the expression of p21, thereby inducing G0/G1 cell cycle arrest. Moreover, borrelidin down-regulated expression of Bcl-2, up-regulated expression of Bax and increased cleavages of caspase-9 and caspase-3 to activate caspase-dependent apoptosis in HCC cells. Borrelidin inhibited migration and invasion through suppressing the expression of MMP-2 and MMP-9 in HCC cells. Further investigation indicated that the anti-tumor effect of borrelidin was mediated by MAPKs signaling pathway. In addition, an in vivo experiment revealed that borrelidin suppressed tumor growth in SMMC7721 xenograft model mice with few side effects. Cell cycle arrest and induced apoptosis were also observed in tumor tissues of model mice treated with borrelidin.

Cytotoxic Fusicoccane-Type Diterpenoids from Streptomyces violascens Isolated from Ailuropoda melanoleuca Feces

Six new fusicoccane-type diterpenoids (2-7) were isolated from the fermentation broth of Streptomyces violascens, which was isolated from Ailuropoda melanoleuca (giant panda) feces. The structures of these new compounds were elucidated by a detailed spectroscopic data and X-ray crystallographic analysis. Compounds 5-7 demonstrated cytotoxicity against five human cancer cell lines, with IC50 values ranging from 3.5 ± 0.7 to 14.1 ± 0.8 μM. Cell adhesion, migration, and invasion assays showed that 6 inhibited the migration and invasion of human hepatocellular carcinoma SMMC7721 cells in a dose-dependent manner. Through further investigation, it was revealed that 6 inhibited the enzymatic activity of matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9), in addition to down-regulating the expressions of MMP-2 and MMP-9 at both the protein and mRNA levels to influence the migration and invasion of cancer cells.

Reclassification of Mzabimyces algeriensis Saker et al. 2015 as Halopolyspora algeriensis comb. nov.

Halopolyspora alba AFM10251T was proposed to represent a novel species of a new genus belonging to the family Actinopolysporaceae in a previous study. The family Mzabimycetaceae , containing one genus, Mzabimyces, was proposed subsequently and Mzabimyces algeriensis H195T was the type strain. However, analysis of 16S rRNA gene sequence similarity showed that the two strains were highly similar (99.2 %). Phenotypic and chemotaxonomic data, as well as DNA-DNA hybridization confirmed that the two strains are different genomic species of the same genus, Halopolyspora. Mzabimyces algeriensis should be classified in the genus Halopolyspora as Halopolysporaalgeriensis comb. nov. The type strain of Halopolysporaalgeriensis is H195T (=DSM 46680T=CECT 8575T).