Cloning, expression and activity analysises of chalcone synthase genes in Carthamus tinctorius / 中草药·英文版

OBJECTIVE@#Flavonoids are the bioactive compounds in safflower (Carthamus tinctorius), in which chalcone synthase (CHS) is the first limiting enzyme. However, it is unclear that which chalcone synthase genes (CHSs) are participated in flavonoids biosynthesis in C. tinctorius. In this study, the CHSs in the molecular characterization and enzyme activities were investigated.@*METHODS@#Putative chalcone biosynthase genes were screened by the full-length transcriptome sequences data in C. tinctorius. Chalcone biosynthase genes in C. tinctorius (CtCHSs) were cloned from cDNA of flowers of C. tinctorius. The cloned gene sequences were analyzed by bioinformatics, and their expression patterns were analyzed by real-time PCR (RT-PCR). The protein of CtCHS in the development of flowers was detected by polyclonal antibody Western blot. A recombinant vector of CtCHS was constructed. The CtCHS recombinant protein was induced and purified to detect the enzyme reaction (catalyzing the reaction of p-coumaryl-CoA and malonyl-CoA to produce naringin chalcone). The reaction product was detected by HPLC and LC-MS.@*RESULTS@#Two full-length CtCHS genes were successfully cloned from the flowers of safflower (CtCHS1 and CtCHS3), with gene lengths of 1525 bp and 1358 bp, respectively. RT-PCR analysis showed that both genes were highly expressed in the flowers, but the expression of CtCHS1 was higher than that of CtCHS3 at each developmental stage of the flowers. WB analysis showed that only CtCHS1 protein could be detected at each developmental stage of the flowers. HPLC and LC-MS analyses showed that CtCHS1 could catalyze the conversion of p-coumaryl-CoA and malonyl-CoA substrates to naringin chalcone.@*CONCLUSION@#CtCHS1 is involved in the biosynthesis of naringin chalcone in safflower.

Comparison of catalytic functions and expression patterns of two pinene synthases from Wurfbainia villosa / 中国中药杂志

Wurfbainia villosa fruit is rich in volatile terpenoids, among which pinene is one of the main components and has anti-inflammatory, antibacterial, anti-tumor, and other pharmacological activities. This research group found that W. villosa fruits were rich in α-pinene by GC-MS, and terpene synthase(WvTPS63, formerly known as AvTPS1) with β-pinene as the main product was cloned and identified, but α-pinene synthase had not been identified. In this study, based on the genome data of W. villosa, we screened and found WvTPS66 with highly similar sequences to WvTPS63, identified enzyme functions of WvTPS66 in vitro, and performed a comparative analysis of sequence, catalytic function, expression pattern, and promoter with WvTPS63. Multiple sequence alignment showed that the amino acid sequences of WvTPS63 and WvTPS66 were highly similar and the conservative motif of terpene synthase was almost identical. In vitro enzymatic experiments on catalytic functions showed that both could produce pinene, and the main product of WvTPS63 was β-pinene, while that of WvTPS66 was α-pinene. Expression pattern analysis showed that WvTS63 was highly expressed in flowers, WvTPS66 was expressed in the whole plant, and the highest expression level was found in the pericarp, which indicated that it might be mainly responsible for the synthesis of α-pinene in fruits. In addition, promoter analysis revealed the presence of multiple regulatory elements related to stress response in the promoter regions of both genes. The findings of this study can provide a reference for the functional study of terpene synthase genes and new genetic elements for pinene biosynthesis.

Functional characterization of SsNES responsible for nerolidol biosynthesis in Senecio scandens / 中国中药杂志

A short terpene synthase gene was obtained by screening the transcriptome data of Senecio scandens. The phylogenetic tree and sequence alignment putatively identified this gene as a nerolidol synthase gene, named SsNES(GenBank MH518312). Protein homology modeling indicated that SsNES contained a complete conserved domain and folded correctly. SsNES was cloned and successfully expressed in Escherichia coli as soluble protein. The biochemical function of SsNES was characterized by E. coli metabolic engineering, which showed that SsNES catalyzed formation of trans-nerolidol with(E, E)-farnesyl diphosphate as the substrate. Nerolidol was also detected in stems and leaves of S. scandens, indicating that SsNES might act as the nerolidol synthase in plant. RT-PCR analysis indicated that SsNES was mainly expressed in stem, flowers and leaves, and no expression was observed in roots. After the treatment of SA, MeJA or Ala, SsNES was induced significantly at 6 h, indicating involvement in the defense response of S. scandens. The identification of SsNES not only clarified biosynthesis of nerolidol in S. scandens, but also provided diversity of sesquiterpene synthase, as well as theoretical basis for disease and pest defense mediated by the terpene metabolites.

Cloning and functional identification of a new NADPH-cytochrome P450 reductase in Andrographis paniculata / 中国中药杂志

Andrographolide is a main active ingredient in traditional Chinese medicine Andrographis paniculata，with a variety of pharmacological activity，widely used in clinical practice. However its biosynthetic pathway has not been resolved. Cytochrome P450 reductase provides electrons for CYP450 and plays an important role in the CYP450 catalytic process. In this study，the coding sequence of A. paniculata CPR was screened and cloned by homologous alignment，named ApCPR4. The ApCPR4 protein was obtained by prokaryotic expression. After isolation and purification，the enzyme activity was identified . The results showed that ApCPR4 could reduce the cytochrome c and ferricyanide in NADPH-dependent manner. In order to verify its function，ApCPR4 and CYP76AH1 were co-transformed into yeast engineering bacteria. The results showed that ApCPR4 could help CYP76AH1 catalyze the formation of rustols in yeast. Real-time quantitative PCR results showed that the expression of ApCPR4 increased gradually in leaves treated with methyl jasmonate (MeJA). The expression pattern was consistent with the trend of induction and accumulation of andrographolide by MeJA，suggesting that ApCPR4 was associated with biosynthesis of andrographolide.

Prokaryotic expression, functional identification of squalene synthase in Alisma orientale and its immunoassay study / 中国中药杂志

Squalene synthase of Alisma orientale catalyzes farnesyl diphosphate (FPP) to form squalene, which is the key regulatory enzyme of the carbon source flow to protostane triterpenes biosynthesis. For further research on the function and expression of AoSS gene, the open reading frame (ORF) of squalene synthase gene (accession no. JX866770) from A. orientale was subcloned into a prokaryotic expression vector pCzn1 and induced the expression of AoSS gene in Escherichia coli BL21(Roseta). The fusion protein was mainly in the form of inclusion bodies and purified to obtain high purity protein. By verifying its functionality through vitro enzymatic reaction, the results showed that the catalytic protein had the catalytic activity of FPP into squalene. In order to research the expression of AoSS in A. orientale, the purified protein was used to immunized rabbits to prepare polyclonal antibody which was then purified, the titer of the antibody was greater than 1∶51 200 by ELISA detection, and displayed good specificity by Western blotting. The prepared antibody was used for immunoassay of AoSS in different organs of A. orientale, and the results showed that the AoSS expression level was the highest in tubers, followed by leaves, and lowest in root. Successful construction of prokaryotic expression vector, validation of gene functions and establishment of rapid immunoassay lay the foundation for further researches on the function and regulation of AoSS gene, and also provide scientific basis on the application of the protostane triterpenes of A. orientale in the field of synthetic biology.

Culture and functional identification of macrophages from human peripheral blood / 中国免疫学杂志

Objective:To isolate monocytes from human peripheral blood mononuclear cells( PBMC) ,induce macrophages,and identify the function of macrophages.Methods:Monocytes were isolated from PBMC using magnetic activated cell sorting( MACS) anti-CD14 microbead.Sorted CD14+and CD14-cells were checked by flow cytometer to evaluate the efficiency of sorting.The sorted CD14+cells were cultured in IMDM media with 10%human AB serum and 10 ng/ml M-CSF for 7 days to generate macrophages,which were identified by morphological features and phagocytosis function.Results:A high purity of monocytes was obtained by MACS anti-CD14 microbead.The percentage of CD14+cells was 10% and 85.8% before and after sorting, respectively.The macrophages were approximately 40-45 μm in maximum diameter and had the fried egg colony morphological features after 7 days culture.The lymphoma ( Raji) cells were efficiently engulfed by macrophages.Conclusion: The high purity of CD14+monocytes is isolated from PBMC and monocyte-derived macrophages efficiently engulfed lymphoma cells.

Isolated culture and functional identification of mouse bone marrow derived tolerogenic dendritic cells / 中国免疫学杂志

Objective:To establish the methods of isolated culture and functional identification of mice bone marrow derived tolerogenic dendritic cells (CD11b+F4/80 +TDCs) in vitro.Methods: Mice bone marrow cells were isolated and cultured to obtain iDCs with the simulation of mouse rmGM-CSF and rmIL-4.CD11b+F4/80 +TDCs were purified by fluorescence-activated cell sorting on day 6.The morphological changes of TDCs were observed with the inverted microscope dynamically .The expression of CD11b+F4/80 +TDCs were analyzed by the flow cytometry .Tolerogenic function of CD11b+F4/80 +TDCs was evaluated by the expression of MHCⅡ, CD83, IDO, TLR-2, IL-10 and TGF-β1.The expression of MHCⅡ was analyzed by the flow cytometry , and the expression of CD83, IDO and TLR-2 were analyzed by immune-histochemistry.The levels of IL-10 and TGF-β1 in the supernatant of CD11b+F4/80 +TDC were analyzed by ELISA .Meanwhile mature DCs ( mDCs) induced by LPS were used as control .Results:The fresh isolated bone marrow cells look like round and small under microscope .After two days of culture , cells became big and formed into clusters . Five or six days later, cells clusters increased, and the morphology of cells became irregular .At the same time, more dendrite ap-peared on the surface of cells .The percentage of CD11b+F4/80 +TDCs induced by rmGM-CSF and rmIL-4 was about 23%, and the purity of the purified BM CD11b+F4/80 +iDC was about 99%.Compared with mDCs, CD11b+F4/80 +TDCs expressed low levels of MHCⅡand CD83 and high levels of IDO, TLR-2, IL-10 and TGF-β1.Conclusion:CD11b+F4/80 +TDCs derived from mouse bone marrow could be induced successfully by rmGM-CSF and rmIL-4 in vitro.CD11b+F4/80 +TDCs showed tolerogenic function by the expressions of IL-10, TGF-β1, IDO and TLR-2.