Sources and Functions of Defenses Against Solar UV Radiationand Photooxidative Stress in Sea Urchins

海胆防御太阳紫外线辐射和光氧化应激的来源和功能

• 批准号: 9316426
• 负责人: J. Malcolm Shick
• 金额: $ 36.01万
• 依托单位: University of Maine
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-01-01 至 1998-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9316426&HistoricalAwards=false
• 关键词: Sources; Functions; Defenses; Against; Solar

9316426 Shick The regulation of defenses against solar ultraviolet radiation-induced photooxidative stress will be studied in sea urchins. Like other marine organisms, sea urchins contain mycosporine-like amino acids (MAAs) which absorb environmentally relevant wavelengths of UV. Various seaweeds eaten by sea urchins are rich in MAAs, and preliminary chromatographic analyses indicate concordance between the MAA levels in seaweed and in sea urchin tissues, especially ovaries. Controlled maintenance of sea urchins on seaweeds lacking or rich in MAAs confirms dietary accumulation of MAAs in the urchins' ovaries, and provides an experimental means to fortify the eggs with these presumptive UV defenses. Published documentation of a UV-protective effect of MAAs is largely circumstantial. Thus, a major objective of the proposed research is to test directly whether MAAs protect echinoid eggs and larvae from exposure to natural and simulated solar UV. If the hypothesis that MAAs do confer protection against UV radiation is correct, dietary fortification of sea urchin ovaries should confer a greater resistance to UV in eggs and larvae; therefore, effects of acute UV exposure on pyrimidine dimer formation in DNA, fertilization, development, and larval survival will be assessed in MAA-rich and MAA-deficient individuals. A comparative study in this project is aimed at determining whether different exposures to solar UV radiation are associated with qualitative and quantitative differences in MAA content. MAA composition and content in a Maine species of sea urchin will be compared with those in a sympatric sand dollar. The sea urchin species matures and spawns in late winter; thus gamete maturation and larval development take place under relatively low levels of UV exposure. In contrast, the sand dollar is mature and spawns repeatedly from June through October, so its eggs and larvae are exposed to higher seasonal UV radiation than the winter- spawning se a urchin and may require more robust photooxidative defenses. The results of this study will have implications for the mechanism of accumulation and effectiveness of natural photooxidative defenses in marine food chains. This is a genuine concern because of deterioration of the protective ozone layer, where boreal marine organisms have evolved under relatively low solar UV exposure. The research may also have importance in the search for natural (dietary) antioxidants, some of which may be active as inhibitors of tumor promotion in human cells. ***

小行星9316426 将研究海胆对太阳紫外线辐射诱导的光氧化应激的防御调节。像其他海洋生物一样，海胆含有类菌孢素氨基酸（MAA），可以吸收与环境相关的紫外线波长。海胆食用的各种海藻富含MAA，初步色谱分析表明海藻和海胆组织，特别是卵巢中的MAA水平一致。海胆在缺乏或富含MAA的海藻上的受控维持证实了海胆卵巢中MAA的饮食积累，并提供了一种实验手段来用这些假定的UV防御来强化卵。 已发表的关于甲基丙烯酸的紫外线防护作用的文献在很大程度上是间接的。因此，拟议研究的一个主要目标是直接测试MAAs是否保护海胆卵和幼虫免受自然和模拟太阳紫外线的照射。如果假设，MAAs确实赋予保护免受紫外线辐射是正确的，海胆卵巢的饮食强化应赋予更大的抵抗紫外线的鸡蛋和幼虫，因此，急性紫外线暴露对嘧啶二聚体形成的DNA，受精，发育和幼虫生存的影响将在MAA丰富和MAA缺乏的个人进行评估。 该项目的一项比较研究旨在确定不同的太阳紫外线辐射暴露是否与甲基丙烯酸含量的定性和定量差异有关。MAA的组成和含量在缅因州种海胆将进行比较，在同域的沙美元。海胆物种在冬季后期成熟和产卵;因此配子成熟和幼虫发育发生在相对低水平的紫外线照射下。相比之下，沙元是成熟的，从6月到10月反复产卵，所以它的卵和幼虫暴露在比冬季产卵的海胆更高的季节性紫外线辐射下，可能需要更强大的光氧化防御。 这项研究的结果将对 海洋食物链中天然光氧化防御的积累和有效性机制。这是一个真正令人关切的问题，因为保护臭氧层的恶化，北方海洋生物在相对较低的太阳紫外线照射下进化。这项研究在寻找天然（饮食）抗氧化剂方面也可能具有重要意义，其中一些抗氧化剂可能在人类细胞中作为肿瘤促进的抑制剂。 ***