title: Antioxidant responses to oleic acid in two-liquid-phase suspension cultures of Taxus cuspidata.
abstract: Two-liquid-phase plant cell cultures employ the use of a partitioning system to redirect extracellular product into a second phase. After the addition of organic solvent, in order to understand the defense system of Taxus cuspidata cells to organic solvent in two-liquid-phase suspension cultures, we investigated cells' antioxidant metabolism. The results showed that T. cuspidata cells responded to oleic acid with oxidative bursts in both intracellular H2O2 and extracellular O2-* production. Inhibition studies with diphenylene iodonium suggested that the key enzyme responsible for oxidative bursts was primarily NADPH oxidase. Investigation of the relationship between reactive oxygen species (ROS) and defense responses induced by oleic acid indicated that 4% (v/v) oleic acid increased the levels of antioxidant enzymes of superoxide dismutase, ascorbate peroxidase, and catalase and the antioxidant capacity of reduced ascorbate and glutathione. However, when oleic acid content reached a critical value (6% [v/v]), no further increase in antioxidant enzymes and antioxidant capacity was observed, indicating that the defense responses played a role in a certain range of oleic acid content, beyond which the overall ROS scavenging machinery was not induced and the peroxidation of membrane lipids emerged.
authors.affiliation: Department of Pharmaceutical Engineering, School of Chemical Engineering & Technology, Tianjin University, PO Box 6888, Tianjin 300072, PR China.
authors.forename: Qiu-Man
authors.initials: QM
authors.lastname: Xu
authors.forename: Jing-Sheng
authors.initials: JS
authors.lastname: Cheng
authors.forename: Zhi-Qiang
authors.initials: ZQ
authors.lastname: Ge
authors.forename: Ying-Jin
authors.initials: YJ
authors.lastname: Yuan
mesh_terms: D000975:Antioxidants / Q000378:metabolism*; D060387:Ascorbate Peroxidases; D001205:Ascorbic Acid / Q000378:metabolism; D002374:Catalase / Q000378:metabolism; D002478:Cells, Cultured; D005978:Glutathione / Q000378:metabolism; D015227:Lipid Peroxidation / Q000187:drug effects; D008315:Malondialdehyde / Q000032:analysis; D019255:NADPH Oxidases / Q000378:metabolism; D019301:Oleic Acid / Q000494:pharmacology*; D018384:Oxidative Stress / Q000187:drug effects; D010544:Peroxidases / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism; D020946:Taxus / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D013997:Time Factors
chemical_list: D000975:Antioxidants; D017382:Reactive Oxygen Species; D019301:Oleic Acid; D008315:Malondialdehyde; D010544:Peroxidases; D060387:Ascorbate Peroxidases; D002374:Catalase; D013482:Superoxide Dismutase; D019255:NADPH Oxidases; D005978:Glutathione; D001205:Ascorbic Acid