Okamoto O K, Colepicolo P
Departamento de Bioquímica, Universidade de São Paulo, Brazil.
Comp Biochem Physiol C Pharmacol Toxicol Endocrinol. 1998 Jan;119(1):67-73. doi: 10.1016/s0742-8413(97)00192-8.
The response of superoxide dismutase (SOD) activity in the marine dinoflagellate Gonyaulax polyedra to chronic (5.0 ppb Hg, 0.5 ppm Cd, 2.0 ppm Pb and 0.1 ppm Cu, during 30 days) and acute (10.0 ppb Hg, 1.0 ppm Cd, 5.0 ppm Pb and 0.25 ppm Cu, during 48 hours) exposure to metals was investigated. Under chronic exposure to Hg, Cd, Pb, and Cu, total SOD activity of metal-treated cells increased during the first day of exposure to plateau levels of 134, 148, 127, and 139% of control values respectively. Under acute metal exposure, SOD activity increases were of similar magnitude but much more rapid (within several hours) and of shorter duration. In addition, assays for oxidative damage to lipids revealed high levels of lipid peroxidation in cells kept in either chronic or acute exposure to metals reaching values 2-fold greater than the control group. Changes in SOD activity were dependent on the metal, its concentration, and the time of exposure. Non-denaturing polyacrylamide gels revealed induction of Fe-SOD and Mn-SOD but not Cu-Zn-SOD isoforms in cells kept under acute exposure to metals. These results suggest that oxidative stress may be an important mediator of metal toxicity in algal systems, with SOD providing antioxidant protection.
研究了海洋甲藻多甲藻（Gonyaulax polyedra）中超氧化物歧化酶（SOD）活性对长期（30天内，汞5.0 ppb、镉0.5 ppm、铅2.0 ppm和铜0.1 ppm）和急性（48小时内，汞10.0 ppb、镉1.0 ppm、铅5.0 ppm和铜0.25 ppm）金属暴露的响应。在长期暴露于汞、镉、铅和铜的情况下，金属处理细胞的总SOD活性在暴露的第一天增加，分别达到对照值的134%、148%、127%和139%的稳定水平。在急性金属暴露下，SOD活性的增加幅度相似，但速度更快（数小时内）且持续时间更短。此外，脂质氧化损伤检测显示，长期或急性暴露于金属的细胞中脂质过氧化水平很高，达到对照组的两倍。SOD活性的变化取决于金属、其浓度和暴露时间。非变性聚丙烯酰胺凝胶显示，急性暴露于金属的细胞中诱导了Fe-SOD和Mn-SOD同工型，但未诱导Cu-Zn-SOD同工型。这些结果表明，氧化应激可能是藻类系统中金属毒性的重要介质，SOD提供抗氧化保护。
