Collaborative Research: Oxidative Stress, Telomere Dynamics and Aging in a Free-Living Organism

这项研究旨在确定组成衰老过程的机制，并证明其在自由生活的脊椎动物自然种群中的健康后果。值得注意的是，鸟类比类似大小的哺乳动物寿命更长。树燕子是使用的模型系统，因为大量已知年龄的个体可以年复一年地重复捕获和采样，而且它们的繁殖成功很容易在它们的一生中衡量。这项研究考察了与自由生活鸟类衰老相关的生理因素的自然变化。来自个别树燕子的纵向样本将被用来跟踪氧化应激、端粒(保护编码DNA的染色体帽，但随着细胞分裂而缩短)的失调，以及免疫功能的下降。生理机制中的个体差异在多大程度上解释了观察到的存活和生殖成功的差异，这将使研究人员能够确定这些可能发生衰老的替代途径的相对重要性。来自不同年龄鸟类的横截面样本将确定每个生理特征的种群平均值如何随年龄变化，纵向样本和横截面样本的比较将区分个体年龄的影响和具有不同特征值的个体之间的选择影响。这项研究将包括一项旨在提高个体燕子代谢率的实验，以检验氧化代谢和随之而来的自由基的产生对衰老和端粒缩短的进程具有重要意义的假设。它将为高中生、本科生和研究生提供实验室和实地培训，以及高中理科教师的参与。这项研究将使对衰老感兴趣的研究人员能够将表型特征值与死亡风险联系起来，并确定衰老在进化上的重要机制。此外，这项研究将提供新的工具，大大加强对生活史策略中权衡取舍的研究。

This research is designed to identify the mechanisms that comprise the process of aging and to demonstrate its fitness consequences within a natural population of free-living vertebrates. Birds are noteworthy for having longer life spans than similar sized mammals. Tree swallows are the model system used because a large number of known-aged individuals can be repeatedly captured and sampled from year to year, and their reproductive success is easily measured across their life span. This research examines natural variation in physiological factors associated with aging in free-living birds. Longitudinal samples from individual tree swallows will be used to track oxidative stress, dysregulation of telomeres (chromosomal caps that protect coding DNA but shorten with cell division), and immune function decline. The extent to which individual variation in physiological mechanisms accounts for observed differences in survival and reproductive success will allow the researchers to identify the relative importance of these alternative pathways through which aging may occur. Samples from a cross-section of birds of different ages will identify how population averages for each physiological trait change with age, and comparison of the longitudinal and cross sectional samples will separate effects of individual aging from effects of selection between individuals with different trait values. The research will include an experiment designed to increase metabolic rates of individual swallows to test the hypothesis that oxidative metabolism and the attendant production of free radicals is causally important to the progression of aging and telomere shortening. It will provide laboratory and field training of high school, undergraduate, and graduate students as well as involvement by high school science teachers. This research will enable researchers interested in aging to link phenotypic trait values and risks of mortality, and identify evolutionarily important mechanisms of aging. In addition, this research will provide new tools to substantially strengthen the study of trade-offs in life history strategies.