Hypersalinity and Hydrogen Peroxide Upregulation of Gene Expression of Antioxidant Enzymes in Ulva fasciata Against Oxidative Stress

• Published in: Marine biotechnology (New York, N.Y.) N.Y.), 2009-04, Vol.11 (2), p.199-209
• Main Authors: Sung, Ming-Shiuan, Hsu, Yi-Ting, Hsu, Yuan-Ting, Wu, Tzure-Meng, Lee, Tse-Min
• Format: Article
• Language: English
• Subjects: Acids; Algae; Antioxidant enzyme; Antioxidants; Antioxidants - metabolism; Ascorbic acid; Biomedical and Life Sciences; Carbonyl compounds; Carbonyl groups; Carbonyls; Catalase; Defense; Engineering; Enzymatic activity; Enzyme activity; Enzymes; Enzymes - metabolism; Freshwater & Marine Ecology; Gene expression; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Plant; Glutathione; Glutathione reductase; Hydrogen peroxide; Hydrogen Peroxide - analysis; Hydrogen Peroxide - pharmacology; Hypersalinity; L-Ascorbate peroxidase; Life Sciences; Lipid peroxidation; Lipids; Manganese; Marine; Microbiology; Original Article; Oxidants - pharmacology; Oxidation; Oxidative stress; Oxidative Stress - drug effects; Peroxidase; Peroxidation; Protein Carbonylation; Proteins; Reactive oxygen species; Real-time quantitative RCR; Reductases; Saline water; Salinity; Scavenging; Sodium Chloride - pharmacology; Studies; Superoxide dismutase; Thalli; Thiobarbituric Acid Reactive Substances; Time Factors; Ulva - drug effects; Ulva - enzymology; Ulva fasciata; Up-regulation; Up-Regulation - drug effects; Zoology
• ISSN: 1436-2228; 1436-2236
• DOI: 10.1007/s10126-008-9134-5

The modulation of manganese superoxide dismutase (MnSOD), FeSOD, ascorbate peroxidase (APX), glutathione reductase (GR), and catalase (CAT) gene expression and activities and antioxidants in Ulva fasciata against hypersalinity (90[per thousand])-induced oxidative stress was studied. Increases in H₂O₂ contents but no changes in lipid peroxidation and protein carbonyl group contents suggest oxidative damage did not occur in 90[per thousand] condition. Antioxidants were consumed for reactive oxygen species (ROS) scavenging indicated by decreased ascorbate and glutathione contents by 90[per thousand]. Antioxidant enzymes were differently expressed by 90[per thousand] for ROS removal. MnSOD activity and transcript increased 1 h after 90[per thousand] treatment with a peak at hour 3, while FeSOD activity increased fast to the plateau after 1 h and its transcript increased after 3 h. APX activity increased 1 h after 90[per thousand] but its transcript rose till 3 h, and GR activity increased after 1 h with a peak at hour 3 but its transcript increased till 3 h. CAT activity and transcript increased after 12 h. Enzyme activity is transcriptionally regulated by 90[per thousand] except a fast increase in FeSOD, APX, and GR activities during 1 h. APX is responsible for early H₂O₂ decomposition while CAT scavenges H₂O₂ in the later period. The inhibition of 90[per thousand] induced increase of H₂O₂ content and FeSOD activity and transcript by treatment of a H₂O₂ scavenger, dimethylthiourea, and the increase of FeSOD transcript of 30[per thousand] grown thalli by H₂O₂ treatment suggest that H₂O₂ mediates the upregulation of FeSOD by hypersalinity while other enzymes is modulated by factors other than H₂O₂.