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Taxus Chinensis (taxus + chinensi)
Selected AbstractsThe Effects of Oligosaccharide and Spores from Aspergillus niger on the Defence Responses of Taxus chinensis Leaves In vitroJOURNAL OF PHYTOPATHOLOGY, Issue 10 2003M. Y. Li Abstract Spores and oligosaccharide of a strain of Aspergillus niger, which had been isolated from the inner bark of Taxus chinensis, were used to treat T. chinensis leaves. The spores decreased the dry weight and chlorophyll content of the leaves, but increased their malondialdehyde content; oligosaccharide induced similar but more moderate changes. The changes in soluble protein, phenolic content, and peroxidase and phenylalanine ammonia-lyase activity were also analysed. Oligosaccharide significantly increased all these, whereas the spores had contrary effects. Results indicate that oligosaccharide, but not the fungal spores, elicited a defence reaction in T. chinensis. Possible reasons for these different effects on T. chinensis leaves in vitro are discussed. [source] Highly efficient strategy for enhancing taxoid production by repeated elicitation with a newly synthesized jasmonate in fed-batch cultivation of Taxus chinensis cellsBIOTECHNOLOGY & BIOENGINEERING, Issue 4 2005Zhi-Gang Qian Abstract A highly efficient bioprocessing strategy was developed for enhancing the production of plant secondary metabolites by repeatedly eliciting a fed-batch culture with a newly synthesized powerful jasmonate analog, 2,3-dihydroxypropyl jasmonate (DHPJA). In suspension cultures of a high taxuyunnanine C (Tc)-producing cell line of Taxus chinensis, 100 ,M DHPJA was added on day 7 to fed-batch cultures with feeding of 20 g L,1 sucrose on the same day. The synergistic effect of elicitation and substrate feeding on Tc biosynthesis was observed, which resulted in higher Tc accumulation than that by elicitation or sucrose feeding alone. More interestingly, both specific Tc yield (i.e., Tc content) and volumetric yield was further improved by a second addition of 100 ,M DHPJA (on day 12) to the fed-batch cultures. In particular, with repeated elicitation and sucrose feeding the Tc volumetric yield was increased to 827 ± 29 mg L,1, which was 5.4-fold higher than that of the nonelicited batch culture. Furthermore, the above novel strategy was successfully applied from shake flask to a 1-L airlift bioreactor. A high Tc production and productivity of 738 ± 41 mg L,1 and 33.2 ± 1.9 mg L,1 d,1, respectively, was achieved, which is higher than previous reports on Tc production in bioreactors. The results suggest that the aforementioned bioprocessing strategy may potentially be applied to other cell culture systems for efficient production of plant secondary metabolites. © 2005 Wiley Periodicals, Inc. [source] Enzymatic Synthesis of Enantiopure ,- and ,-Amino Acids by Phenylalanine Aminomutase-Catalysed Amination of Cinnamic Acid DerivativesCHEMBIOCHEM, Issue 2 2009Bian Wu Abstract The phenylalanine aminomutase (PAM) from Taxus chinensis catalyses the conversion of ,-phenylalanine to ,-phenylalanine, an important step in the biosynthesis of the N -benzoyl phenylisoserinoyl side-chain of the anticancer drug taxol. Mechanistic studies on PAM have suggested that (E)-cinnamic acid is an intermediate in the mutase reaction and that it can be released from the enzyme's active site. Here we describe a novel synthetic strategy that is based on the finding that ring-substituted (E)-cinnamic acids can serve as a substrate in PAM-catalysed ammonia addition reactions for the biocatalytic production of several important ,-amino acids. The enzyme has a broad substrate range and a high enantioselectivity with cinnamic acid derivatives; this allows the synthesis of several non-natural aromatic ,- and ,-amino acids in excellent enantiomeric excess (ee >99,%). The internal 5-methylene-3,5-dihydroimidazol-4-one (MIO) cofactor is essential for the PAM-catalysed amination reactions. The regioselectivity of amination reactions was influenced by the nature of the ring substituent. [source] Isolation and structure of I-deoxybaccatin VI from the root of taxus chinensis, rehd. var. maireiCHINESE JOURNAL OF CHEMISTRY, Issue 7 2004Hai-Xia Lin Abstract Deoxybaccatin VI (4,,7,,9,,10,,13,-penta-acetoxy-2a-benzoyloxy-5,,20-epoxytax-11-ene) was isolated from the roots of Taxus chinensis, Rehd. var mairei. The structural assignments of the compound were based on their spectral data, including 2D NMR experiments and chemical correlation. The X-ray crystallographic analysis of 1-deoxybaccatin VI provided unambiguous characterization for the structures. In the structure, the six-membered A ring exhibits boat conformation, the eight-membered B ring adopts boat-chair conformation, and the six-membered C ring exhibits a sofa conformation. [source] | |||||||||||||