Gas chromatography-mass spectrometric analysis of Jatropha curcas leaf extracts prepared by supercritical fluid CO2 extraction / 南方医科大学学报

<p><b>OBJECTIVE</b>To analyze the bioactive components in Jatropha curcas leaves using gas chromatography-mass spectrometry (GC-MS).</p><p><b>METHODS</b>The bioactive components were extracted from J. curcas leaves by supercritical fluid CO2 extraction and analyzed by using GC-MS.</p><p><b>RESULTS</b>Seventy peaks were detected by GC-MS, and 43 compounds were identified (61.43%). Among the identified compounds, 16 had a content of more than 1%, and the total contents of these 16 compounds reached 81.36%. The four most abundant components were 22,23-dihydro-stigmasterol (16.14%), alpha-tocopherol (15.18%), beta-amylin (7.73%) and dotriacontanol (7.02%). The content of gamma-tocopherol reached 2.88% and vitamin E reached 18.06% in the extract.</p><p><b>CONCLUSION</b>J. curcas leaves contain multiple compounds with anti-tumor, anti-virus and antimicrobial activities.</p>

Tumor-specific T cell recptor gene transfection promotes memory T cell differentiation in vitro / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate effect of tumor-specific T cell receptor gene transfection on memory T cell differentiation in vitro.</p><p><b>METHODS</b>TCRVbeta7.1 gene was transferred into peripheral blood mononuclear cells (PBMCs) obtained from healthy adults, and the expression of Vbeta7.1 was detected by flow cytometry before and after the transfection. Memory T cell differentiation was induced by stimulation with the hepatocarcinoma cell line BEL-7402 in vitro. The expression of surface molecules CD45RO, CD45RA and CCR7 was analyzed by flow cytometry to identify the phenotype and subsets of the memory T cells. Fluorescence-activated cell sorting was performed to detect the apoptosis of the tumor cells, and enzyme-linked immunoabsorbent assay was used to determine the production of interferon-gamma (IFN-gamma) for assessing the immune function of the memory T cells.</p><p><b>RESULTS</b>Flow cytometry showed that TCRVbeta7.1 gene was efficiently expressed after transfection. After stimulation by the tumor cells in vitro, the expression of CD45RO in TCRVbeta7.1 gene-modified T cells increased gradually, and analysis of the coexpression of CD45RA and CCR7 revealed that the effector memory T cells constituted the majority of the differentiated memory T cells. The apoptotic rate of the tumor cells induced by the T cells increased significantly with also obviously increased INF-gamma secretion in the memory T cells.</p><p><b>CONCLUSION</b>Tumor-specific TCRVbeta7.1 gene transfection can promote the differentiation of the memory T cells, the majority of which belongs to effector memory T cells that perform immune functions by inducing apoptosis and cytokine secretion.</p>

Effect of Paraformaldehyde Fixation on the FRET Efficiency Calculation between Fluorescent Proteins / 中国生物工程杂志

Objective:To investigate the effect of paraformaldehyde fixation on measuring the protein-protein interaction by fluorescence resonance energy transfer(FRET)to resolve the problem of FRET efficiency calculation in excess-movement cells.Methods:The C terminals of TCR ? chain(TRA)and TCR ? chain(TRB)genes,which were ideal for protein-protein interaction research,were fused with ECFP and EYFP gene respectively by fusion PCR and transferred into target cell.A grou Pcells were fixed in paraformaldehyde(0.5%)for 0.5~1h and another left alive,then these cells were subject to ECFP/EYFP FRET calculation with confocal laser scanning microscope.The ECFP/EYFP FRET efficiencies in live and fixed cell were analyzed and compared.Results:There is no significant statistical difference between the ECFP/EYFP FRET efficiencies of live cell and cell fixed with lower paraformaldehyde concentration and shorter incubation time.Conclusion:fixation with low-concentration paraformaldehyde and short-time incubation has no distinct influence on measuring protein-protein interaction,and facilitated the FRET calculation in excess-movement cells.