RUI: Oxygen Defense Mechanisms in Legume Root Nodules

固氮生物特别容易受到氧气的伤害 由于固氮酶的氧敏感性和 固氮所需的强还原条件。 在 豆科植物根瘤，氧毒性是最小化的行动 包括超氧化物歧化酶在内的特殊防御酶， 抗坏血酸过氧化物酶、单脱氢抗坏血酸还原酶和 抗坏血酸-谷胱甘肽循环的其他酶。 主要 这项研究的目的是表征酶 参与氧气防御，以确定亚细胞 定位这些酶，以确定这些酶是否 是特定于结核的，并检查 氧防御和固氮之间的联系。 酶学研究将涉及纯化和二维凝胶 电泳后进行免疫学检测。 纯化的酶将用于制备抗血清， 亚细胞定位免疫学检测 光学和电子显微镜。 无效结节将 检查是否缺乏氧防御酶。 具有有效根瘤的植物将在根部生长 不同氧浓度的大气及其响应 将监测的结节防御机制。% 豆类提供了世界蛋白质的很大一部分 而不需要氮肥。 加强 这些植物以及其他作物的固氮作用， 一个有吸引力的替代增加对氮的依赖 肥料. 为了实现这些改进，我们 必须了解生物化学和生理学， 氮根瘤生理学 这项研究调查了 负责最大限度地减少氧毒性的酶， 结节 更好地了解这些酶可能会使 因为他们的操纵可能会反过来增加产量 收益率 此外，今后可能需要这些资源， 作物中新固氮菌群的开发 物种。*//

Nitrogen-fixing organisms are especially vulnerable to oxygen damage due to the oxygen sensitivity of nitrogenase and to the strong reducing conditions required to fix nitrogen. In legume root nodules, oxygen toxicity is minimized by action of special defense enzymes including superoxide dismutase, ascorbate peroxidase, monodehydroascorbate reductase and other enzymes of the ascorbate-glutathione cycle. The main objectives of this research are to characterize the enzymes involved in oxygen defense, to determine the subcellular localization of these enzymes, to determine if these enzymes are nodule-specific, and to examine the criticality of the link between oxygen defense and nitrogen fixation. Enzymological studies will involve purification and 2-D gel electrophoresis followed by immunological detection. Purified enzymes will be used to prepare antisera for immunological detection of subcellular localization using both light and electron microscopy. Ineffective nodules will be examined for deficiencies in oxygen defense enzymes. Plants with effective nodules will be grown in root atmospheres of various oxygen concentrations and the response of nodule defense mechanisms will be monitored.%%% Legumes provide a substantial portion of the world's protein without requiring nitrogen fertilizer. The enhancement of nitrogen fixation in these, as well as other crop plants, is an attractive alternative to increasing reliance on nitrogen fertilizers. In order for such improvements to come about we must understand both the biochemistry and physiology of nitrogen nodule physiology. This research investigates the enzymes responsible for minimizing oxygen toxicity in these nodules. A better understanding of these enzymes may allow for their manipulation which may, in turn, increase crop yields. Furthermore, they may be required for the future development of new nitrogen-fixing associations in crop species.***//