Lean mass dynamics during flight and refueling in migratory birds: causes, consequences, and mechanisms

候鸟飞行和加油过程中的瘦质量动力学：原因、后果和机制

基本信息

批准号：
1656726
负责人：
Alexander Gerson
金额：
$ 75.67万
依托单位：
University of Massachusetts Amherst
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2017
资助国家：
美国
起止时间：
2017-02-01 至 2022-01-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1656726&HistoricalAwards=false
关键词：
Lean mass dynamics during flight

项目摘要

Migratory birds complete long journeys between the breeding and wintering grounds. This journey is comprised of a series of long-distance non-stop flights that can be 6-8 hours in duration for most songbirds, but could last for days in some shorebirds. During flight, metabolic rate is very high and migratory birds primarily fuel these long flights with stored fat. However, protein breakdown also occurs during flight resulting in dramatic organ and muscle mass reductions. Such dramatic reductions in muscle and organ mass could result in significant functional losses of organ systems but this has not been thoroughly investigated. This project proposes to investigate the causes, consequences, and mechanisms of protein breakdown during flight in migratory birds. This research will further our insight into the unique metabolism of migratory birds in flight, deepen our understanding of how migratory birds maintain homeostasis despite dramatic reductions in critical organ systems, and will provide novel insight into the molecular and biochemical mechanisms involved in muscle and organ degeneration and regeneration. Additionally, this project will provide a platform to engage many undergraduate and graduate students from diverse backgrounds in integrative research, providing exposure and training in a broad range of cutting edge techniques that will be applicable to many STEM fields. These students will also develop and implement science communication and outreach programming for middle school students in a local low-income school district.During flight, metabolic rate is 10-fold higher than at rest and rates of water loss are very high, placing extreme demands on the ability of birds to manage water and energy budgets. Migratory birds fuel long-duration flight primarily by the oxidation of fat, but a large amount of protein is also catabolized, resulting in reductions in muscle and organ mass of 20% - 40% from pre-flight levels. However, the functional limits and underlying mechanisms of lean mass catabolism during flight remain unclear. Migratory birds will be flown in a climatically controlled wind tunnel for extended periods to evaluate hypotheses for the causes of protein catabolism, while the consequences and mechanisms of protein catabolism will be assessed by measuring whole animal and tissue level changes in key physiological processes, and by investigating transcriptional differences that occur during flight. This will provide insight into physiological mechanisms that allow the maintenance of homeostasis despite dramatic organ and muscle remodeling, and will further our understanding of the basic mechanisms controlling phenotypic flexibility in vertebrates. Graduate and undergraduate students will receive integrative training in many cutting-edge techniques as part of this project, which will be broadly applicable to many STEM careers. This research will provide genuine research experiences for many undergraduates with emphasis on providing mentorship and training to encourage women and students from underrepresented groups to further pursue careers in STEM disciplines.

候鸟在繁殖和越冬地之间完成了长途旅行。这次旅程包括一系列长途不停的航班，对于大多数鸣鸟来说，持续时间可能为6-8小时，但在某些shore鸟中可以持续数天。在飞行过程中，代谢率很高，候鸟主要用储存的脂肪为这些长途飞行燃料。但是，在飞行过程中也会发生蛋白质分解，从而导致器官和肌肉质量降低。这种肌肉和器官质量的急剧减少可能会导致器官系统的重大功能损失，但尚未对此进行彻底的研究。该项目建议研究候鸟飞行过程中蛋白质破裂的原因，后果和机制。这项研究将进一步洞悉飞行中迁徙鸟类的独特代谢，加深我们对候鸟如何维持体内平衡的理解，尽管关键器官系统的大幅降低，并将为涉及肌肉和器官变性和再生的分子和生化机制提供新的见解。此外，该项目将提供一个平台，以吸引许多来自不同背景的本科生和研究生在综合研究中，从而在广泛的尖端技术中提供曝光和培训，这些技术将适用于许多STEM领域。这些学生还将为当地低收入学区的中学生开发和实施科学传播和外展计划。在飞行中，代谢率比静止时高10倍，水损失率很高，对鸟类管理水和能量预算的能力非常有要求。候鸟燃料长期飞行主要是由于脂肪的氧化而进行的，但是大量蛋白质也被分解代谢，导致肌肉和器官质量的减少20％至40％，40％至40％。但是，飞行过程中瘦质量分解代谢的功能极限和基本机制尚不清楚。迁徙鸟类将在气候控制的风洞中长期飞行，以评估蛋白质分解代谢原因的假设，而蛋白质分解代谢的后果和机制将通过测量整个动物和组织水平的关键生理过程中的变化以及研究飞行过程中发生的转录差异来评估。这将为您提供生理机制的洞察力，尽管器官和肌肉重塑了戏剧性，但可以维持体内平衡，并将进一步了解我们对控制脊椎动物表型灵活性的基本机制的理解。作为该项目的一部分，研究生和本科生将接受许多尖端技术的综合培训，这将广泛适用于许多STEM职业。这项研究将为许多本科生提供真正的研究经验，重点是提供指导和培训，以鼓励来自人数不足的群体的妇女和学生进一步从事STEM学科的职业。