Pinocembrin, belonging to flavanons, was isolated from various plants. Pinocembrin has a variety of pharmacological activities, such as neuroprotective effect, antimicrobial activity, and antioxidant efficacy. Pinocembrin was approved as class I drugs to its phase II clinical trial by CFDA in 2009, mainly used for the treatment of ischemic stroke. As a promising compound, the manufacturing technologies of pinocembrin, including chemical synthesis, extraction from plant and synthetic biology, have attracted many attentions. Compared with the first two technologies, synthetic biology has many advantages, such as environment-friendly and low-cost. Construction of biosynthetic pathway in microorganism offers promising results for large scale pinocembrin production by fermentation after taking lots of effective strategies. This article reviews some of recent strategies in microorganisms to improve the yield, with focus on the selection of appropriate the key enzyme sources, the supply of precursors and cofactors by microorganisms, the choice of substance and the level of the key enzyme expression.
Biosynthetic Pathways ; Fermentation ; Flavanones ; biosynthesis ; Industrial Microbiology ; Plants ; Synthetic Biology

Abstract: The first-line drug artemisinin is widely used against malaria. Commercially available artemisinin is extracted from plants. However, the lack of sufficient raw material, artemisinin and the cost associated with the drug's manufacture have limited the supply of ACT to most malaria sufferers in the Developing World. As such, it is important to develop a low cost, fine to environment and high-quality method to supply sufficient and reliable quantities of artemisinin in the future. The field of synthetic biology, which utilizes cell factories to manipulate microbial metabolism to enhance the production of artemisinin and its intermediates, has a particularly strong impact by providing new platforms for chemical production. After a brief introduction of the artemisinin biosynthetic pathway, the present review focuses on the introduction of artemisinin biosynthetic genes, such as the genes encoding amorpha-4, 11-diene monooxygenase, NADPH: cytochrome P450 oxidoreductase, artemisinic aldehyde delta 11(13) reductase and aldehyde dehydrogenase. The review also addresses general considerations for potential contributions of synthetic biology to artemisinin production, with an emphasis on factors influencing interest compounds production in chassis cells.

Human enterovirus 71 (EV71) is one of the major etiological agents for the hand, foot, and month disease (HFMD) and is causing frequent, widespread occurrence in the mainland of China. The single positive-stranded RNA genome of EV71 is translated into a single polyprotein which is autocleavaged into structural and nonstructural proteins. The functions of many nonstructural proteins characterized in the life cycle of virus are potential targets for blocking viral replication. This article reviews the studies of the structures and functions of nonstructural proteins of EV71 and the anti-enterovirus 71 drugs targeting on these nonstructural proteins.

Influenza A/H1N1 virus-encoded nonstructural, or NS1, protein inhibits the 3'-end processing of cellular pre-mRNAs by binding the cellular protein: the 30-kDa subunit of CPSF (cleavage and polyadenylation specificity factor, CPSF30). CPSF30 binding site of the NS1 protein is a potential target for the development of drugs against influenza A/H1N1 virus. A yeast two-hybrid screening system was constructed and used for screening Chinese medicines that inhibit the interaction of the A/H1N1 flu NS1 protein and human CPSF30 protein. The NS1 gene of A/H1N1 virus was amplified by consecutive polymerase chain reaction (PCR), and the human CPSF30 gene of HeLa cell cloned by reverse transcriptase-polymerase chain reaction (RT-PCR). Then the two gene fragments confirmed by sequencing were subcloned into the yeast expression vectors pGBKT7 and pGADT7, respectively. The two constructs, bait vector pGBKNS1 and prey vector pGADCPSF, were co-transformed into yeast AH109. The eight individual yeast colonies were picked and subjected to verification by PCR/gel electrophoresis. The inhibition of the NS1-CPSF30 interaction was allowed the identification of selective inhibitors. The four of more than thirty identified Chinese medicines, including 'Shuanghuanglian oral liquid', showed the strong inhibition of the NS1-CPSF30 interaction.

Peptide cyclization, a pivotal approach to modifying linear precursors of proteins and pepticles, has been used to enhance their biological activities and serum stabilities. Recently, sortase A (SrtA) from Staphyloccus aureus becomes a promising new technology for efficiently incorporating site specific modifications into proteins, conjugating the cell surface and cyclizing the linear peptides. In this study, we constructed two recombinant expression systems, one with chitin binding domain and the other with six-histidine tag and chitin binding domain on the N-terminal of SrtA, separately. The results of enzymatic kinetics indicate that the two recombinant tags do not impair the transpeptidase activity of SrtA compared with the standard reaction reported under the same reaction condition. The two synthesized peptides with N-ternimal three glycines and C-terminal penta-amino acid motif, LPETG, were cyclized using immobilized and recycled SrtA. The SrtA-based cyclization promises to represent a simple method for easy and efficient enzymatic synthesis of large cyclic peptides.

The synthetic biology matures to promote the heterologous biosynthesis of the well-known drug paclitaxel that is one of the most important and active chemotherapeutic agents for the first-line clinical treatment of cancer. This review focuses on the construction and regulation of the biosynthetic pathway of paclitaxel intermediates in both Escherichia coli and Saccharomyces cerevisiae. In particular, the review also features the early efforts to design and overproduce taxadiene and the bottleneck of scale fermentation for producing the intermediates.

The cyclotides are a family of cyclic "mini" proteins that occur in Violaceae, Rubiaceae and Cucurbitaceae plant families and contain a head-to-tail cyclic backbone and a cystine knot arranged by three disulfide bonds. To study the natural cyclotides of V tianshanica, dried herb was extracted with 50% ethanol, and the concentrated aqueous extract was subjected to a solvent-solvent partitioning between water and hexane, ethyl acetate and n-butanol, separately. The n-butanol extract containing cyclotides was subjected to column chromatography over Sephadex LH-20, eluted with 30% methanol. The subfractions were directly reduced by DTT and analyzed by reverse-phase HPLC. The peaks with different retention times were shown on the profile of RP-HPLC and collected. The cyclotides were speculated based on masses range from 3 000 to 3 500 Da. The purified cyclotides were reduced with DTT, alkylated with iodoacetamide, and then were cleaved with endoproteinase Glu-C, endoproteinase Lys-C and Trypsin, separately. The digested peptides were purified on RP-HPLC and analyzed on MALDI TOF/TOF analyzer. A new cyclotide, cycloviolacin T1 and a reported cyclotide varv E were systemically determined using MALDI TOF/TOF system. So the method for the isolation and characterization of cyclotides was quickly built up in succession.

Three cyclotides were isolated from the whole plant of Viola yedoensis in this study. The two, vary peptide E and cycloviolacin Y5, were previously reported, and a novel cycloviolacin VY1 was characterized according to the interpretation of MS/MS fragmentation of peptides which were produced from the reduced and alkylated parent peptide with the digestion of Endo Lys-C, trypsin and chymotrypsin, separately. The stability of remarkable resistance to proteolytic degradation by trypsin and chymotrypsin, and that of thermal denaturation was confirmed again. Besides, the IC50 value of cycloviolacin VYI against influenza A H1N1 virus was (2.27 +/- 0.20) microg x mL(-1). It is the first cyclotide reported with anti-influenza A H1N1 virus activity in vitro assay.

Objective:Autoimmune mechanisms, including cellular and humoral immune, are likely to participate in the pathogenesis of at least a subgroup of idiopathic dilated cardiomyopathy(IDC), in which cellular immune-mediated one plays a more important role. Cytotoxic T lymphocyte associated antigen-4(CTLA-4) is the major negative regulatory factor of cellular immunity. This study was conducted to investigate the association of CTLA-4 gene promoter -318C/T polymorphism, exon 1 A/G polymorphism and 3′ untranslated region microsatellite polymorphism with susceptibility to IDC in Han Chinese.Methods:Polymerase chain reaction-restriction fragment length polymorphisms(PCR-RFLP) techniques were used to analyze the polymorphisms of CTLA-4 promoter -318, exon 1 A/G and 3′ untranslated region in the unrelated Han ethnic population in Heilongjiang Province(including 72 IDC patients and 100 normal controls). Serum sCTLA-4 was tested by ELISA. The relationship of CTLA-4 genotype and alleles frequencies with sCTLA-4 was evaluated by linear regression analysis.Results:Compared with controls, the frequencies of GG genotype(0.604 2 and 0.739 6, P=0.012) and the G allele(0.360 0 and 0.560 0, P=0.008) were significantly increased in patients with IDC. Increased serum sCTLA-4 was found in the IDC group compared with the controls[(1.87?1.06)?g/L vs (0.54?0.19)?g/L, P

Objective:To analyze the implementation effect of single disease payment policy for day surgery (hereinafter referred to as the policy), for references for the reform of medical insurance payment.Methods:By collecting the information of inpatients from 2017 to 2019 in a tertiary hospital, the research group took patients with colorectal benign tumor and nodular goitre as the policy implementation group and the control group respectively. 2017-2018 was the pre implementation stage of the policy, and 2019 was the post implementation stage of the policy. The difference-in-differences (DID) model was used to analyze the changes in indicators such as length of stay and hospitalization expenses after policy implementation, under whether the policy is implemented or not, as well as before or after policy implementation.Results:A total of 2 419 patients were included, including 927 patients with nodular goiter in the control group and 1 492 patients with colorectal benign tumors in the policy implementation group (688 patients before the policy implementation and 804 patients after the policy implementation). The results of DID showed that the hospital days for patients with colorectal benign tumor decreased by 56.53%, the hospitalization expenses decreased by 26.51%, the out-of-pocket expenses decreased by 26.66%, the treatment expenses increased by 11.96%, the drug expenses decreased by 50.29% and the consumables expenses decreased by 20.23% after the implementation of the policy.Conclusions:The implementation of the policy could reduce length of stay, hospitalization expenses and out-of-pocket expenses, optimize the structure of hospitalization expenses, improve the efficiency of hospital diagnosis and treatment, and help the hospital realize its transformation from a size expansion to a quality and benefit expansion.