The Role of phosphoenolpyruvate carboxykinase and reactive oxygen species in the

描述（由申请人提供）：地球上几乎所有的生物体都有支持厌氧代谢的基本代谢途径，但许多生物体，包括大多数脊椎动物，在没有分子氧的情况下无法长期生存。摘要一年生南极鱼胚胎是研究脊椎动物缺氧耐受性和缺氧敏感性机制的理想模型。A. Limnaeus经历一个独特的发育休眠期，称为滞育。最近的证据表明，A. Limnaeus有一些非常独特的生理适应，与长期缺氧的耐受性有关。休眠和活跃发育的A. Limnaeus可以在250摄氏度的无氧环境中存活数月。A. Limnaeus在缺氧暴露的最初几个小时内显示出ATP的大量消耗，并在同一时间范围内失去它们的线粒体膜电位。这两个事件通常与其他脊椎动物细胞的细胞死亡有关，但A。limnaeus很快从这些线粒体生理和能量学的剧烈变化中恢复过来。这些观察结果表明，A.与其他脊椎动物相比，甚至与其他对缺氧表现出相当耐受性的脊椎动物相比，Limnaeus胚胎具有一些非凡的特征。我将确定代谢途径，支持缺氧耐受性在孤立的细胞A。Limnaeus，评估缺氧和缺氧恢复期间的线粒体功能和能量学，并检验由磷酸烯醇式丙酮酸羧激酶支持的替代代谢途径对缺氧存活至关重要的假设。通过使用该提案中概述的综合方法，我们有望创建一个更完整的图片缺氧耐受细胞的细胞生理学，如果这种特殊的脊椎动物极端微生物。 公共卫生相关性：心脏病和中风是发达国家绝大多数死亡的原因。人类心脏和脑组织对缺氧的极端敏感性在细胞水平上知之甚少。通过了解支持一年生鳉鱼（Austrofundulus limnaeus）胚胎极端缺氧耐受性的细胞机制，我们可能能够开发治疗方法来调解或预防心脏病发作和中风对人类的破坏性影响。

DESCRIPTION (provided by applicant): Almost all organisms on Earth share the basic metabolic pathways that support anaerobic metabolism, and yet many organisms, including most vertebrates, cannot survive for long without molecular oxygen. Embryos of the annual killifish Austrofundulus limnaeus are an excellent model for investigating the mechanistic basis of anoxia-tolerance and anoxia-sensitivity in vertebrates. Embryos of A. limnaeus undergo a unique period of developmental dormancy called diapause. Recent evidence suggests that embryos of A. limnaeus have some very unique physiological adaptations that are associated with tolerance of long-term anoxia. Both dormant and actively developing embryos of A. limnaeus can survive for months without oxygen at 250C. Embryos of A. limnaeus display a massive depletion of ATP during the initial hours of anoxic exposure and lose their mitochondrial membrane potential during this same time frame. These two events are typically associated with cell death in other vertebrate cells, but embryos of A. limnaeus quickly recover from these drastic changes in mitochondrial physiology and energetics. These observations imply that cells of A. limnaeus embryos have some extraordinary characteristics compared to other vertebrates, and even to other vertebrates that exhibit substantial tolerance of anoxia. I will identify the metabolic pathways that support anoxia tolerance in isolated cells of A. limnaeus, assess mitochondrial function and energetics during anoxia and recovery from anoxia, and test the hypothesis that an alternate metabolic pathways supported by the enzyme phosphoenolpyruvate carboxykinase is critical for the survival of anoxia. By using the integrative approaches outlined in the proposal we can hopefully create a more complete picture of the cellular physiology of anoxia-tolerance in the cells if this exceptional vertebrate extremophile. PUBLIC HEALTH RELEVANCE: Heart disease and stroke are responsible for the vast majority of deaths in the developed world. The extreme sensitivity of human heart and brain tissue to lack of oxygen is poorly understood at the cellular level. By understanding the cellular mechanisms that support extreme anoxia tolerance in embryos of the annual killifish, Austrofundulus limnaeus, we may be able to develop treatments to mediate or prevent the damaging effects of heart attacks and strokes to humans.