ANTIOXIDANT METABOLISM IN CHLAMYDOMONAS

衣藻中的抗氧化剂代谢

基本信息

批准号：
6490268
负责人：
KRISHNA K NIYOGI
金额：
$ 20.9万
依托单位：
UNIVERSITY OF CALIFORNIA BERKELEY
依托单位国家：
美国
项目类别：
财政年份：
1999
资助国家：
美国
起止时间：
1999-01-01 至 2003-12-31
项目状态：
已结题

项目摘要

Reactive oxygen species (ROS) are generated inevitably in cells of all aerobic organisms, from bacteria plants and animals. Coping with the potentially damaging consequences of ROS generation is a problem of broad biological significance. The involvement of excited and highly reactive intermediates in oxygenic photosynthesis poses unique problems for algae and plants with respect to the generation of ROS. The proposed research plan is focused on the question of how photosynthetic organisms prevent or minimize photo-oxidative damage caused by ROS. To dissect antioxidant defenses in the chloroplast, mutants of the unicellular green alga Chlamydomonas reinhardtii, have been isolated. Several mutants affect the metabolism of xanthophyll pigments, which have critical roles in photoprotection in all algae and plants. An npq1 lor1 double mutant, which is deficient in lutein and zeaxanthin, undergoes photo-oxidative bleaching in high light, presumably due to increased production and/or decreased quenching of ROS, especially singlet oxygen. The proposed research will examine the types of photo- oxidative damage and the responses of various antioxidant systems in npq1 lor1 cells. Isolation of the genes affected in the xanthophyll mutants will enable determination of the molecular basis for the mutant phenotypes and will provide a strong foundation for further genetic analysis, including isolation of suppressors of npq1 lor1. The generation and/or scavenging of other ROS is perturbed in another group of mutants, which will be characterized using a combination of molecular genetic, biochemical, and physiological approaches. Understanding the metabolism and function of xanthophylls and other antioxidants in algae and plants will provide insights into the important roles of these molecules in preventing age-related diseases such as macular degeneration in humans and will enable engineering of antioxidant metabolism in plants to benefit human nutrition and health.

所有细胞中都不可避免地产生活性氧（ROS）需氧生物，来自细菌、植物和动物。应对 ROS 生成的潜在破坏性后果是一个问题广泛的生物学意义。兴奋和高度参与含氧光合作用中的反应中间体带来了独特的问题对于藻类和植物来说，与 ROS 的产生有关。这拟议的研究计划重点关注光合作用如何进行的问题生物体可以预防或最大程度地减少由 ROS 引起的光氧化损伤。到剖析叶绿体中的抗氧化防御，突变体已分离出单细胞绿藻莱茵衣藻。几种突变体影响叶黄素色素的代谢，在所有藻类和植物的光保护中发挥着关键作用。一个npq1 lor1 双突变体，缺乏叶黄素和玉米黄质，在高光下发生光氧化漂白，可能是由于 ROS 的产生增加和/或猝灭减少，尤其是单线态氧。拟议的研究将检查照片的类型氧化损伤和各种抗氧化系统的反应 npq1 lor1 细胞。叶黄素中受影响的基因的分离突变体将能够确定突变体的分子基础表型，将为进一步的遗传提供坚实的基础分析，包括 npq1 lor1 抑制子的分离。这其他 ROS 的生成和/或清除在另一组中受到干扰突变体，将使用分子组合来表征遗传、生化和生理学方法。了解藻类中叶黄素和其他抗氧化剂的代谢和功能植物将提供对这些重要作用的见解预防黄斑等年龄相关疾病的分子人类的退化将使抗氧化剂工程成为可能植物的新陈代谢有利于人类的营养和健康。