Oxidative stress causes coral bleaching during exposure to elevated temperatures
Oxidative stress causes coral bleaching during exposure to elevated temperatures
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DOI：
10.1007/s003380050073
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发表时间：
1997-07-01
期刊：
影响因子：
3.5
通讯作者：
Lesser, MP
中科院分区：
文献类型：
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作者：
Lesser, MP
气温升高和太阳紫外线（UV）辐射被认为是珊瑚和其他具有光合自养共生体的无脊椎动物中共生藻类丧失（即白化）的最新原因。珊瑚白化的一种假设机制涉及在甲藻共生体和损失的组织中产生还原氧中间体或有毒氧，随后导致细胞损伤和共生体排出。在温度引起的应激和暴露在充分的太阳辐射下，对加勒比珊瑚细叶姬松茸的光合作用进行了测量，结果显示光合作用性能下降，随后出现白化。将珊瑚暴露于在温度引起的应激期间清除活性氧的外源抗氧化剂，可以提高最大光合作用能力，使其与在采集地点环境温度下测量的珊瑚无法区分。此外，这些抗氧化剂可以防止珊瑚“白化”并影响珊瑚宿主共生体丧失的机制。这些观察结果证实了氧化应激在漂白现象中的作用，无论是由升高的温度还是暴露于紫外线辐射引起的。
Elevated temperatures and solar ultraviolet (UV) radiation have been implicated as recent causes for the loss of symbiotic algae (i.e., bleaching) in corals and other invertebrates with photoautotrophic symbionts. One hypothesized mechanism of coral bleaching involves the production of reduced oxygen intermediates, or toxic oxygen, in the dinoflagellate symbionts and]lost tissues that subsequently causes cellular damage and expulsion of symbionts. Measurements of photosynthesis in the Caribbean coral Agaricia tenuifolia, taken during temperature-induced stress and exposure to full solar radiation, showed a decrease in photosynthetic performance followed by bleaching. Exposure of corals to exogenous antioxidants that scavenge reactive oxygen species during temperature-induced stress improves maximum photosynthetic capacity to rates indistinguishable from corals measured at the ambient temperature of their site of collection. Additionally, these antioxidants prevent the coral from ''bleaching'' and affect the mechanism of symbiont loss from the coral host. These observations confirm a role for oxidative stress, whether caused by elevated temperatures or exposure to UV radiation, in the bleaching phenomenon.