The effect of La, Ce was firstly tested on growth of the Taxus(T.) cuspidata cell suspensions, biosynthesis and release of taxol. The results indicate that the growth pattern of T.cuspidata cells is altered si...The effect of La, Ce was firstly tested on growth of the Taxus(T.) cuspidata cell suspensions, biosynthesis and release of taxol. The results indicate that the growth pattern of T.cuspidata cells is altered significantly by adding high concentration of rare earth in the medium. The lag and exponential phases of cell growth are shortened, the stationary phase disappears and the biomass fluctuates periodically during the decline phase. The rare earth compounds added in the exponential phase obviously increase the taxol biosyntheis and release yields of T.cuspidata cells, and the supplement of carbon source in the medium containing rare earth is also favorable to taxol biosynthesis.展开更多
Compound 1 as a key intermediate of 1, 7, 9-trideoxytaxol was synthesized in ten steps from a biosynthetically available taxane, Sinenxan A. The key steps in the synthesis were deoxygenation at C-14, allylic oxidatio...Compound 1 as a key intermediate of 1, 7, 9-trideoxytaxol was synthesized in ten steps from a biosynthetically available taxane, Sinenxan A. The key steps in the synthesis were deoxygenation at C-14, allylic oxidation at C-13 and construction of the oxetane ring.展开更多
The effects of survivin antisense RNA on proliferation of leukemia cell line HL-60 and taxol-induced chemotherapy was explored. A cDNA fragment of survivin obtained by RT-PCR was inserted into a plamid vector named pc...The effects of survivin antisense RNA on proliferation of leukemia cell line HL-60 and taxol-induced chemotherapy was explored. A cDNA fragment of survivin obtained by RT-PCR was inserted into a plamid vector named pcDNA3 in the reverse direction. The vector encoding antisense RNA of survivin was confirmed by restriction enzyme digestion and DNA sequencing. The recombinant plasmid was delivered into HL-60 cells by electroporation. Growth curves were plotted based on cell counting. Trypan blue dye exclusion assay and MTT assay were carried out after the cells were incubated with taxol. DNA gel electrophoresis and nuclear staining were performed for cell apoptosis assay. The correct construction of the recombinant plasmid has been identified by restriction enzyme digestion and DNA sequencing. A stable down-regulation has been achieved in HL-60 SVVas cells after G418 selection. Compared to HL-60 cells, the proliferation of HL-60 SVVas cells was significantly inhibited （P〈0.05）. Cytotoxicity assays indicated that IC50 of HL-60 SVVas for taxol was relatively lower than controls （P〈0.01）. Apoptosis assays revealed that taxol-induced apoptosis was detected in HL-60 SVVas cells incubated with 50 ng/ml taxol for 12 h, while in HL-60 cells incubated with 100 ng/ml taxol for 72 h. It was suggested that Survivin antisense RNA could inhibit the proliferation of HL-60 cells and enhance taxol-induced apoptosis in HL-60 cells, which may lay an experimental foundation for further research on gene therapy in leukemia.展开更多
The hallmark of apoptosis, in suspension cultures of Taxus spp. cells induced by fungal extractive or by abiotic means, was studied by total DNA agarose gel electrophoresis and in situ end-labeling. The cleavage of nu...The hallmark of apoptosis, in suspension cultures of Taxus spp. cells induced by fungal extractive or by abiotic means, was studied by total DNA agarose gel electrophoresis and in situ end-labeling. The cleavage of nuclear DNA (nDNA) into oligonucleosomal fragments(DNA laddering) was a characteristic of apoptosis, which involved cell shrinkage, condensation of cytoplasm and tracheary elements differentiation. Terminal deoxynucleotidy transferase-mediated dUTP nick end in situ labeling (TUNEL) assay of Taxus spp. cells showed that fungal extractive or abiotic elicltors (Ce4+, Taxol, H2O2) induced TUNEL positive. Also, the increase of the apoptotic cell ratio was accompanied by the increase of secondary metabolites (especially Taxol). These results suggest that apoptosis may have some coincidence with biosynthesis of Taxol. The implication of apoptosis for the production of secondary metabolites in plant cell cultures is discussed.展开更多
Aflatoxins are the potent toxic, mutagenic, heterogenic and carcinogenic metabolites produced by species of A. flavus and A. parasiticus. In the present study, an attempt has been made to prevent aflatoxin production ...Aflatoxins are the potent toxic, mutagenic, heterogenic and carcinogenic metabolites produced by species of A. flavus and A. parasiticus. In the present study, an attempt has been made to prevent aflatoxin production using an anticancerous drug taxol. Taxol (Paclitaxel) is a well known drug for its anticancerous property mainly to treat breast and ovarian cancers. It was obtained from Taxus brevifolia and it was also obtained from the endophytic fungi present in Taxus brefivolia [1]. Therefore, this drug is specifically selected to screen its activity on the control of A. flavus and AFB1 production at various concentrations. Among the 6 concentrations used, 3 μg of taxol was found to be suitable to control the growth and AFB1 production. The content of AFB1 found at this concentration was 6 ppm by TLC and 6.3 ppm by HPTLC. The complete elimination of AFB1 might require higher concentrations of taxol.展开更多
Homologation of protected taxol side chen 8 from 4 was accomplished stereospecifically through the key intermediate diazo ketone 5 which was actually isolated. The structures of 5 and 7 were identified by spectrometri...Homologation of protected taxol side chen 8 from 4 was accomplished stereospecifically through the key intermediate diazo ketone 5 which was actually isolated. The structures of 5 and 7 were identified by spectrometric methods, mainly 1H-NMR, 1R, 13C-NMR and DEPT techniques.展开更多
文摘The effect of La, Ce was firstly tested on growth of the Taxus(T.) cuspidata cell suspensions, biosynthesis and release of taxol. The results indicate that the growth pattern of T.cuspidata cells is altered significantly by adding high concentration of rare earth in the medium. The lag and exponential phases of cell growth are shortened, the stationary phase disappears and the biomass fluctuates periodically during the decline phase. The rare earth compounds added in the exponential phase obviously increase the taxol biosyntheis and release yields of T.cuspidata cells, and the supplement of carbon source in the medium containing rare earth is also favorable to taxol biosynthesis.
基金This research work was financially supported by NNSFC.
文摘Compound 1 as a key intermediate of 1, 7, 9-trideoxytaxol was synthesized in ten steps from a biosynthetically available taxane, Sinenxan A. The key steps in the synthesis were deoxygenation at C-14, allylic oxidation at C-13 and construction of the oxetane ring.
基金grants from the 863 program of China (No.2006AA02Z158)Wuhan Development Program of China (No. 2003500201628)
文摘The effects of survivin antisense RNA on proliferation of leukemia cell line HL-60 and taxol-induced chemotherapy was explored. A cDNA fragment of survivin obtained by RT-PCR was inserted into a plamid vector named pcDNA3 in the reverse direction. The vector encoding antisense RNA of survivin was confirmed by restriction enzyme digestion and DNA sequencing. The recombinant plasmid was delivered into HL-60 cells by electroporation. Growth curves were plotted based on cell counting. Trypan blue dye exclusion assay and MTT assay were carried out after the cells were incubated with taxol. DNA gel electrophoresis and nuclear staining were performed for cell apoptosis assay. The correct construction of the recombinant plasmid has been identified by restriction enzyme digestion and DNA sequencing. A stable down-regulation has been achieved in HL-60 SVVas cells after G418 selection. Compared to HL-60 cells, the proliferation of HL-60 SVVas cells was significantly inhibited （P〈0.05）. Cytotoxicity assays indicated that IC50 of HL-60 SVVas for taxol was relatively lower than controls （P〈0.01）. Apoptosis assays revealed that taxol-induced apoptosis was detected in HL-60 SVVas cells incubated with 50 ng/ml taxol for 12 h, while in HL-60 cells incubated with 100 ng/ml taxol for 72 h. It was suggested that Survivin antisense RNA could inhibit the proliferation of HL-60 cells and enhance taxol-induced apoptosis in HL-60 cells, which may lay an experimental foundation for further research on gene therapy in leukemia.
文摘The hallmark of apoptosis, in suspension cultures of Taxus spp. cells induced by fungal extractive or by abiotic means, was studied by total DNA agarose gel electrophoresis and in situ end-labeling. The cleavage of nuclear DNA (nDNA) into oligonucleosomal fragments(DNA laddering) was a characteristic of apoptosis, which involved cell shrinkage, condensation of cytoplasm and tracheary elements differentiation. Terminal deoxynucleotidy transferase-mediated dUTP nick end in situ labeling (TUNEL) assay of Taxus spp. cells showed that fungal extractive or abiotic elicltors (Ce4+, Taxol, H2O2) induced TUNEL positive. Also, the increase of the apoptotic cell ratio was accompanied by the increase of secondary metabolites (especially Taxol). These results suggest that apoptosis may have some coincidence with biosynthesis of Taxol. The implication of apoptosis for the production of secondary metabolites in plant cell cultures is discussed.
文摘Aflatoxins are the potent toxic, mutagenic, heterogenic and carcinogenic metabolites produced by species of A. flavus and A. parasiticus. In the present study, an attempt has been made to prevent aflatoxin production using an anticancerous drug taxol. Taxol (Paclitaxel) is a well known drug for its anticancerous property mainly to treat breast and ovarian cancers. It was obtained from Taxus brevifolia and it was also obtained from the endophytic fungi present in Taxus brefivolia [1]. Therefore, this drug is specifically selected to screen its activity on the control of A. flavus and AFB1 production at various concentrations. Among the 6 concentrations used, 3 μg of taxol was found to be suitable to control the growth and AFB1 production. The content of AFB1 found at this concentration was 6 ppm by TLC and 6.3 ppm by HPTLC. The complete elimination of AFB1 might require higher concentrations of taxol.
文摘Homologation of protected taxol side chen 8 from 4 was accomplished stereospecifically through the key intermediate diazo ketone 5 which was actually isolated. The structures of 5 and 7 were identified by spectrometric methods, mainly 1H-NMR, 1R, 13C-NMR and DEPT techniques.
