Mining and identification of a biosynthetic gene cluster producing xanthocillin analogues from Penicillium chrysogenum MT-40, an endophytic fungus of Huperzia serrata / 生物工程学报

Xanthocillin is a unique natural product with an isonitrile group and shows remarkable antibacterial activity. In this study, the genome of an endophytic fungus Penicillium chrysogenum MT-40 isolated from Huperzia serrata was sequenced, and the gene clusters with the potential to synthesize xanthocillin analogues were mined by local BLAST and various bioinformatics analysis tools. As a result, a biosynthetic gene cluster (named for) responsible for the biosynthesis of xanthocillin analogues was identified by further heterologous expression of the key genes in Aspergillus oryzae NSAR1. Specifically, the ForB catalyzes the synthesis of 2-formamido-3-(4-hydroxyphenyl) acrylic acid, and the ForG catalyzes the dimerization of 2-formamido-3-(4-hydroxyphenyl) acrylic acid to produce the xanthocillin analogue N, N'-(1, 4-bis (4-hydroxyphenyl) buta-1, 3-diene-2, 3-diyl) diformamide. The results reported here provide a reference for further discovery of xanthocillin analogues from fungi.

Advances of the novel immunosuppressant brasilicardin A / 生物工程学报

Brasilicardin A (BraA) is a natural diterpene glycoside isolated from the pathogenic actinomycete Nocardia brasiliensis IFM 0406 with highly potent immunosuppressive activity (IC50=0.057 μg/mL). BraA potently inhibits the uptake of amino acids that are substrates for amino acid transport system L of T cells, which is different from the existing clinical immunosuppressants. BraA is more potent in a mouse mixed lymphocyte reaction and less toxic against various human cell lines compared with the known clinical immunosuppressants, such as cyclosporin A, ascomycin and tacrolimus. Therefore, BraA attracted more attention as a new promising immunosuppressant. However, the development of this promising immunosuppressant as drug for medical use is so far hindered because BraA has the unusual and synthetically challenging skeleton and shows the low-yield production in the natural pathogenic producer. This review introduces the molecular structure of BraA, its activity, mechanism of action, chemical synthesis of BraA analogs, heterologous expression of gene cluster, and an application of combining microbial and chemical synthesis for production of BraA, with the aim to facilitate the efficient production of BraA and its analogs.

Seven new 3,4-dihydro-furanocoumarin derivatives from Angelica dahurica / 中草药·英文版

OBJECTIVE@#To study the chemical constituents of the roots of Angelica dahurica, a well-known Chinese herbal medicine named Baizhi in Chinese.@*METHODS@#Compounds were separated by various chromatographies, and the structures of new compounds were elucidated based on the analysis of their spectroscopic and spectrometric data (1D, 2D NMR, HRESI MS, IR, and UV). The absolute configurations of new compounds were determined by the calculated electronic circular dichroism and chemical derivatization. The inhibitory activities of all isolates against nitric oxide (NO) production were evaluated using lipopolysaccharide-activated RAW 264.7 macrophage cells.@*RESULTS@#Seven new 3,4-dihydro-furanocoumarin derivatives ( 1a/ 1b, 2a/ 2b, 3a/ 3b, 4) together with a known furanocoumarin ( 5) were isolated from the roots of A. dahurica. The new compounds included three pairs of enantiomers, (4S, 2''R)-angelicadin A ( 1a)/(4R, 2''S)-angelicadin A ( 1b), (4S, 2''S)-angelicadin A ( 2a)/(4R, 2''R)-angelicadin A ( 2b), and (4S, 2''S)-secoangelicadin A ( 3a)/(4R, 2''R)-secoangelicadin A ( 3b), together with (4R, 2''R)-secoangelicadin A methyl ester ( 4). The known xanthotoxol ( 5) inhibited the NO production with the half-maximal inhibitory concentration (IC50) value of (32.8 ± 0.8) µmol/L, but all the new compounds showed no inhibitory activities at the concentration of 100 µmol/L.@*CONCLUSION@#This is the first report of the discovery of 3,4-dihydro-furanocoumarins from A. dahurica. The results are not only meaningful for the understanding of the chemical constituents of A. dahurica, but also enrich the reservoir of natural products.

Production of curcumin by engineered Escherichia coli / 生物工程学报

Curcumin is exclusively isolated from Zingiberaceae plants with a broad spectrum of bioactivities. In the present study, we used the diketide-CoA synthase (DCS) and curcumin synthase (CURS) genes to construct a non-natural fusion gene encoding diketide-CoA synthase::curcumin synthase (DCS::CURS). This fusion protein, together with the acetyl coenzyme A carboxylase (ACC) and the 4-coumarate coenzyme A ligase (4CL), were introduced into Escherichia coli for the production of curcumin from ferulic acid. The process is divided into two stages, the growth stage using LB medium and the fermentation stage using the modified M9 medium. The yield of curcumin reached 386.8 mg/L by optimizing the induction of protein expression in the growth stage, and optimizing the inoculum volume, medium composition and fermentation time in the fermentation stage, as well as the addition of macroporous resin AB-8 into the second medium to attenuate the toxicity of the end product. The exploitation of the non-natural fusion protein DCS::CURS for the production of curcumin provides a new alternative to further promoting the production of curcumin and the related analogues.

Chemical constituents of Clematis manshurica / 中草药

Objective To study the chemical constituents of Clematis manshurica. MethodsThe extract from the roots and rhizomes of C. manshurica was subjected to chromatography on silica gel and Sephadex LH-20 column. The compounds obtained were identified on the basis of their physicochemical and spectroscopic evidences. ResultsEleven compounds were isolated and their structures were elucidated as squalene (Ⅰ), friedelin (Ⅱ), hexacosoic acid (Ⅲ), ?-sitosterol (Ⅳ), stigmasterol (Ⅴ), oleanolic acid (Ⅵ), ?-daucosterol (Ⅶ), 5-hydroxymethyl-2-furaldehyde (Ⅷ), methyl 3, 4-dihydroxy-phenyl lactate (Ⅸ), 5R-dihydro-5-hydroxymethyl-2(3H)-furanone (Ⅹ), 5R-5-hydroxymethyl-2(5H)-furanone (Ⅺ). ConclusionAll the compounds except for ?-sitosterol are isolated from the plant for the first time.