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Excessive Copper Induces the Production of Reactive Oxygen Species, which is Mediated by Phospholipase D, Nicotinamide Adenine Dinucleotide Phosphate Oxidase and Antioxidant Systems
Author(s) -
Yu ZhongLian,
Zhang JinGuang,
Wang XueChen,
Chen Jia
Publication year - 2008
Publication title -
journal of integrative plant biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.734
H-Index - 83
eISSN - 1744-7909
pISSN - 1672-9072
DOI - 10.1111/j.1744-7909.2007.00609.x
Subject(s) - nicotinamide adenine dinucleotide phosphate , tbars , reactive oxygen species , antioxidant , phosphatidic acid , chemistry , nadph oxidase , biochemistry , oxidase test , phospholipase d , thiobarbituric acid , ascorbic acid , enzyme , lipid peroxidation , food science , phospholipid , membrane
Tobacco BY‐2 suspension cells were used to study the chemical damage and its associated mechanisms caused by Cu 2+ . Treatment with 100 μmol/L Cu 2+ generated a large amount of H 2 O 2 and thiobarbituric acid‐reactive substances (TBARS) in cells. Using phospholipase D (PLD) specific inhibitor (1‐butanol) or phosphatidic acid (PA), we demonstrated that PLD plays an important role in the generation of H 2 O 2 and TBARS. Semi‐quantitative reverse‐transcriptase polymerase chain reaction and enzyme activity assays with wild type and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase‐overexpressing BY‐2 cells revealed that PLD and PA are the key factors leading to NADPH oxidase activation, which is responsible for H 2 O 2 and TBARS production induced by Cu 2+ . Moreover, the content of ascorbic acid (AsA), an effective antioxidant, was sharply reduced in BY‐2 cells exposed to excessive Cu 2+ . Furthermore, a significant downregulation of the enzymes of AsA biosynthesis and the antioxidant system was found. This evidence suggests that excessive Cu 2+ ‐elevated reactive oxygen species (ROS) production is caused by upregulated PLD that elevates the activity of NADPH oxidase and its collapsed antioxidant systems that scavenges ROS.