Ca2+/Calmodulin regulate UV-B induction of antioxidant enzyme activity and gene expression in Ulva fasciata Delile (Chlorophyta, Ulvales)

• Main Authors: Shih-Hung Wu Huang, 吳黃世宏
• Other Authors: Tse-Min Lee
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/66794799600465275096

碩士 === 國立臺灣海洋大學 === 水產養殖學系 === 94 === The role of Ca2+/Calmodulin in the induction of the antioxidant enzymes activity and their gene expression in a marine macroalga Ulva fasciata Delile exposed to Ultraviolet-B(2.5W/m2)-induced oxidative stress was investigated. The activities of SOD (superoxide dismutase), CAT (catalase) and APX (ascorbate peroxidase) were assessed by exposing Ulva fasciata segments to calcium (10 mM)-containing, ethyleneglycol- bis-(2-aminoethyl ether) N, N, N’-tetraacetic acid (EGTA) (15 mM)- containing, both Ca2+and EGTA-containing artificial seawater with UV-B (2.5 W/m2) radiation for 4 or 9 h. The results show that calcium would inhibit the SOD activity, more significant for 9-h UV-B radiation. Besides, the treatment of EGTA and verapamil (5 μM), a voltage-dependent Ca2+ channel blocker, would decrease the Ca2+ availability and enhance the SOD activity. The CAT activity would increase in treatment of EGTA whether UV-B (2.5 W/m2) was radiated or not. Without UV-B (2.5W/m2) radiation, treatment of EGTA would conspicuously decrease the APX activity, however, it is worthy of notice that the APX activity is independent of the calcium concentration after the UV-B radiation. On the other hand, treatment of calmodulin inhibitors, chlorpromazine (CP，0.1-0.5 μM), trifluorperazine (TFP，0.5-1.0 μM) or N-(6-aminohexyl)-5-chloro-1- naphthalene-sulfonamide (W7，20 μM), the activities of SOD and APX would enhance and the activity of CAT would conversely decrease with UV-B radiation for nine hours. The analog of W7, N-(6-aminohexyl)-1- naphthalene-sulfonamide (W5，20 μM), has no significant effects on APX activity. Based on the data of northern blotting is in accordance with the activities of APX and CAT. Therefore, we suggested that Ca2+/Calmodulin are involved in the response of UV-B-induced stress in Ulva fasciata.