ABSTRACT
Pyran- and furanocoumarins are key representatives of tetrahydropyrans and tetrahydrofurans, respectively, exhibiting diverse physiological and medical bioactivities. However, the biosynthetic mechanisms for their core structures remain poorly understood. Here we combined multiomics analyses of biosynthetic enzymes in Peucedanum praeruptorum and in vitro functional verification and identified two types of key enzymes critical for pyran and furan ring biosynthesis in plants. These included three distinct P. praeruptorum prenyltransferases (PpPT1-3) responsible for the prenylation of the simple coumarin skeleton 7 into linear or angular precursors, and two novel CYP450 cyclases (PpDC and PpOC) crucial for the cyclization of the linear/angular precursors into either tetrahydropyran or tetrahydrofuran scaffolds. Biochemical analyses of cyclases indicated that acid/base-assisted epoxide ring opening contributed to the enzyme-catalyzed tetrahydropyran and tetrahydrofuran ring refactoring. The possible acid/base-assisted catalytic mechanisms of the identified cyclases were theoretically investigated and assessed using site-specific mutagenesis. We identified two possible acidic amino acids Glu303 in PpDC and Asp301 in PpOC as vital in the catalytic process. This study provides new enzymatic tools in the epoxide formation/epoxide-opening mediated cascade reaction and exemplifies how plants become chemically diverse in terms of enzyme function and catalytic process.
ABSTRACT
Objective To investigate the feasibility of lymphokine activated killer(LAK) cells induced from cord blood used as adoptive cellular immunotherapy for human cancer.Methods Mononuclear cells were separated from umbilical blood(UBMC) by Ficoll,and stimulated by IL-2.The phenotypes(CD3/ CD4/ CD8) of the mononuclear cells were assayed by Flow cytometry,and their lethal activity on K562 or SKOV6 assayed by MTT colometric.The peripheral blood mononuclear cells were used as the control.Results The in vitro anti-tumor effect of LAK from cord blood was significant.Conclusion LAK from cord blood can be a source of adoptive cellular immunotherapy in the treatment of human cancer.
ABSTRACT
Objective To study the immune function of gynecologic malignant tumor patients with chemotherapy and the influence of cord blood transfusion.Methods Thirty cases of gynecologic malignant tumor patients with chemotherapy and 30 of healthy women were divided into three groups,MTT colorimetry and flow cytometry was used to determine the change of immune function.Results ①The number of CD4 + T cell in patients was lower than that in healthy women and CD8 + was much higher.The ratio of CD4 +/CD8 + was inverted( t=2.56,P