Design of Oxidative Capacities in Hymenopteran Flight Muscles

膜翅目飞行肌肉氧化能力的设计

• 批准号: 0075817
• 负责人: Raul Suarez
• 金额: --
• 依托单位: University of California-Santa Barbara
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-07-15 至 2005-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0075817&HistoricalAwards=false
• 关键词: Design; Oxidative; Capacities; Hymenopteran; Flight

Flying insects achieve the highest known mass-specific rates of aerobic metabolism in the Animal Kingdom. How these high metabolic flux rates are achieved to support flight is poorly understood. During flight, steady state rates of mechanical work define rates of ATP hydrolysis and resynthesis. The applicant asks how capacities for ATP synthesis are related to ATP requirements for flight. In previous studies using honeybees (Apis mellifera), the applicant found remarkably close matches between enzymatic capacities for glycolysis and glycolytic rates achieved during flight. As an extension of these studies, further research will beconducted to determine how closely mitochondrial oxidative capacities match requirements during flight. An important question is whether honeybee flight muscle mitochondria possess inherently higher capacities for respiration and oxidative phosphorylation than mitochondria from vertebrate homeotherm muscles. Honeybee mitochondria will be isolated and characterized to determine how oxidative capacities are related to the respiration rates achieved in flight. Further studies to investigate the basis for high respiration rates in honeybees will involve mechanistic studies of electron transfer reactions in isolated muscle mitochondria.The relationships between biochemical capacities and physiological flux rates will be further explored in a comparative study using various species of Euglossine (orchid) bees, which vary greatly in size and are known to display an inverse relationship between body mass and mass-specific metabolic rate during flight. It is proposed that in Euglossine bees, the inverse relationship between body mass and mass-specific aerobic metabolic rate is achieved partly through variation in mitochondrial content and structure, as well as higher enzyme turnover rates (electron transfer rate per enzyme molecule) with declining body mass. These unique studies will shed light upon how metabolic enzymes function in vivo and the principles governing the design of biochemical capacities. The rules that govern how much enzyme is "enough but not too much" are poorly understood. The applicant's research program is based on the belief that progress towards this goal is of fundamental importance to biology.

在动物王国中，飞行昆虫实现了最高的已知特定质量的有氧代谢率。这些高代谢通量率是如何实现的，以支持飞行是知之甚少。在飞行过程中，机械功的稳态速率决定了ATP水解和再合成的速率。申请人询问ATP合成能力与飞行ATP要求之间的关系。在先前使用蜜蜂（Apis mellifera）的研究中，申请人发现糖酵解的酶能力与飞行期间实现的糖酵解速率之间非常接近的匹配。作为这些研究的延伸，将进行进一步的研究，以确定线粒体氧化能力与飞行期间的需求有多接近。一个重要的问题是蜜蜂飞行肌线粒体是否具有固有的呼吸和氧化磷酸化能力比脊椎动物恒温肌肉线粒体更高。蜜蜂线粒体将被分离和表征，以确定氧化能力如何与飞行中实现的呼吸速率相关。进一步研究蜜蜂高呼吸速率的基础将涉及离体肌肉线粒体中电子转移反应的机制研究。生化能力和生理通量率之间的关系将在使用各种Euglossine（兰花）蜜蜂的比较研究中进一步探索，其尺寸变化很大，并且已知在飞行期间显示出身体质量和质量特异性代谢率之间的反比关系。有人提出，在Euglossine蜜蜂，体质量和特定质量的有氧代谢率之间的反比关系，部分是通过线粒体含量和结构的变化，以及较高的酶周转率（电子转移率每酶分子）与体质量下降。这些独特的研究将阐明代谢酶在体内的功能以及生物化学能力设计的原则。关于多少酶是“足够但不太多”的规则，人们知之甚少。申请人的研究计划基于这样的信念：实现这一目标的进展对生物学至关重要。