Age-related Variation in Metabolism and Temperature Sensitivity in Muscle: Mechanisms and Evolutionary Implications

肌肉代谢和温度敏感性与年龄相关的变化：机制和进化意义

• 批准号: 9317969
• 负责人: James Marden
• 金额: $ 21.3万
• 依托单位: Pennsylvania State Univ University Park
• 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 1997-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9317969&HistoricalAwards=false
• 关键词: Age; related; Variation; Metabolism; Temperature

9317969 Marden Physiological processes in animal tissues are strongly affected by temperature, with resultant effects on whole- organism performance and fitness. The precise manner in which tissue and organismal performance are affected by temperature is called "thermal sensitivity". Studies of lower vertebrates have led to an understanding of some of the molecular and cellular mechanisms that determine thermal sensitivity, and to an appreciation of how variation in thermal sensitivity among species affects their geographic distribution and ecology. However, current evolutionary models lack consensus regarding fitness of variation in thermal sensitivity, with competing models concentrating on how thermal sensitivity affects niche breadth, aerobic performance capacity, high-temperature tolerance during peak activity, and compromises between high- and low- temperature performance capacity. Ability to distinguish among these competing hypotheses is hampered by the scarcity of species in which there is both i) variation in thermal sensitivity among individuals, and ii) ability to observe and measure fitness variation among animals possessing different thermal sensitivities. This project takes advantage of the presence of large-scale variation in thermal sensitivity among different-aged individuals in a dragonfly, and the ability to manipulate and observe these abundant and highly active animals in a field setting. Results of these experiments will allow critical tests of the competing models for the evolution of thermal sensitivity. This project will also make a detailed examination of the cellular and molecular mechanisms that affect variation in thermal sensitivity of muscle performance. Preliminary data indicate that a switch from anaerobic to aerobic metabolism accompanies the age-related change in thermal sensitivity, and that variation in expression of a calcium regulatory protein, troponin-t, may be particularly important in determining how mu scle functions in changing thermal and pH conditions. An opportunity to enhance our understanding of the basic physiology of troponin-t is particularly significant, since presence of this molecule in the blood stream has recently become the most sensitive clinical indicator of severe myocardial infraction in humans(i.e. heart attack). In summary, this project will examine physiology and ecology of a model organism in order to provide new data and perspectives that will influence our understanding of both basic evolutionary processes and muscle physiology. ***

9317969马登动物组织的生理过程受温度的强烈影响，从而影响整个生物体的生产性能和适应性。组织和机体性能受温度影响的精确方式被称为“热敏性”。对低等脊椎动物的研究使我们了解了一些决定热敏性的分子和细胞机制，并使我们认识到物种间热敏性的变化如何影响它们的地理分布和生态。然而，目前的进化模型对热敏性变异的适应度缺乏共识，竞争模型集中在热敏性如何影响生态位宽度、有氧运动能力、高峰活动时的高温耐受性以及高低温性能能力之间的折衷。区分这些相互竞争的假说的能力受到物种稀缺性的阻碍，这些物种既存在个体之间的热敏性差异，也存在ii)观察和测量具有不同热敏性的动物之间的适合度差异的能力。该项目利用了蜻蜓不同年龄个体在热敏性方面存在的大规模差异，以及在野外环境中操纵和观察这些数量丰富且高度活跃的动物的能力。这些实验的结果将允许对热敏度演化的竞争模型进行关键测试。该项目还将详细研究影响肌肉表现热敏性变化的细胞和分子机制。初步数据表明，从无氧代谢到有氧代谢的转变伴随着与年龄相关的热敏性变化，钙调节蛋白肌钙蛋白-t表达的变化可能在决定肌肉在变化的温度和pH条件下的功能方面特别重要。加强我们对肌钙蛋白-t基本生理学的理解的机会尤其重要，因为这种分子在血液中的存在最近已成为人类严重心肌梗死（即心肌梗死）最敏感的临床指标。心脏病)。总之，该项目将研究模式生物的生理学和生态学，以提供新的数据和观点，这将影响我们对基本进化过程和肌肉生理学的理解。＊＊＊