Primary Metabolism And Secondary Metabolism Of Taxus Sp. Cells Affected By Immobilization Microenvironment

The surface chemical composition on the cell wall, cell growth, fatty acid composition of lipid, reactive oxygen species, metal ions and taxol production of Taxus sp. cells immobilized on polyurethane foam were investigated, so the primary metabolism and secondary metabolism were studied in the immobilization microenvironment.The surface chemical composition on the cell wall was analyzed by X-ray photoelectron spectroscopy (XPS). the ratios of N/C, N/P and the weight percentage of peptides on the wall surface of cells immobilized the foam surface were significantly higher but the weight percentages of hydrocarbon-like substance and polysaccharides were obviously less than those of the wall surface of the cells immobilized inside the foam. The ratios of K/C, N/C and N/P on the wall surface of the immobilized cells decreased.The relationships between membrane fatty acid composition percentage and reactive oxygen species content and taxol production were investigated by the use of the two-phase separation, gas phase chromatography and H₂O₂ addition, respectively. The contents of linoleic acid and linolenic acid increased but the content of stearic acid decreased in the immobilization state. Meanwhile the fatty acid compositions of plasma membrane had a tendency of shifting towards unsaturation and the index of unsaturated fatty acid (IUFA) increased. There existed a good synchrony relationship between taxol and IUFA contents, while the relationship between taxol and stearic acid contents was negative. Intracelluar H₂O₂ and extracelluar H₂O₂ and O2-。increased significantly at late growth phase (after day 20) in the microenvironment. The addition of exogenous H₂O₂ (15μM and 20μM) led to an increase of PAL activity and an obvious accumulation of taxol, but had no effects on the MDA content and membrane permeability.Intracellular contents of K⁺, Mg²⁺ and Ca²⁺ were analyzed in the different foam layer by an inductively coupled plasma-optical emission spectrometry and the relationship between Distinct spatio-temporal distribution of K⁺, Mg²⁺ and Ca²⁺ and Taxol production were studied. The rule of metal ions content in the inner foam layer were Ca²⁺ > Mg²⁺ > K⁺. In contrast, the intracellular ion contents decreased in a sequence of K⁺, Ca²⁺ and Mg²⁺ in the outer foam layer and middle foam layer. Amongthe three foam layers, the Ca²⁺, Mg²⁺ and taxol contents reached the highest but the K+ content was the lowest in the inner foam layer.