Downs C A, Fauth John E, Halas John C, Dustan Phillip, Bemiss John, Woodley Cheryl M
EnVirtue Biotechnologies, Inc., Walnut Creek, CA, USA.
Free Radic Biol Med. 2002 Aug 15;33(4):533-43. doi: 10.1016/s0891-5849(02)00907-3.
During the past two decades, coral reefs have experienced extensive degradation worldwide. One etiology for this global degradation is a syndrome known as coral bleaching. Mass coral bleaching events are correlated with increased sea-surface temperatures, however, the cellular mechanism underlying this phenomenon is uncertain. To determine if oxidative stress plays a mechanistic role in the process of sea-surface temperature-related coral bleaching, we examined corals along a depth transect in the Florida Keys over a single season that was characterized by unusually high sea-surface temperatures. We observed strong positive correlations between accumulation of oxidative damage products and bleaching in corals over a year of sampling. High levels of antioxidant enzymes and small heat-shock proteins were negatively correlated with levels of oxidative damage products. Corals that experienced oxidative stress had higher chaperonin levels and protein turnover activity. Our results indicate that coral bleaching is tightly coupled to the antioxidant and cellular stress capacity of the symbiotic coral, supporting the mechanistic model that coral bleaching (zooxanthellae loss) may be a final strategy to defend corals from oxidative stress.
在过去二十年中，全球范围内的珊瑚礁都经历了广泛的退化。这种全球退化的一个病因是一种被称为珊瑚白化的综合征。大规模珊瑚白化事件与海表温度升高相关，然而，这一现象背后的细胞机制尚不确定。为了确定氧化应激在与海表温度相关的珊瑚白化过程中是否起作用，我们在佛罗里达群岛的一个深度断面沿着珊瑚进行了一个季节的观察，该季节的特点是海表温度异常高。在一年的采样过程中，我们观察到氧化损伤产物的积累与珊瑚白化之间存在强烈的正相关。高水平的抗氧化酶和小热休克蛋白与氧化损伤产物的水平呈负相关。经历氧化应激的珊瑚具有更高的伴侣蛋白水平和蛋白质周转活性。我们的结果表明，珊瑚白化与共生珊瑚的抗氧化和细胞应激能力紧密相关，支持了珊瑚白化（虫黄藻损失）可能是珊瑚抵御氧化应激的最终策略这一机制模型。
