Mechanistic Linkages for the Pace of Life, Life History, and Environment in Birds

点击翻译按钮获取中文摘要

Joseph B. WilliamsProposal # IOS-1036914Mechanistic linkages for the pace of life, life-history, and environment in birdsIn comparison with a similar sized mammal, birds are remarkable in that they have a higher rate of metabolism, higher body temperature, higher blood glucose levels, and higher life-time energy expenditure, all traits thought to reduce life span. Yet, birds live longer than a similar-sized mammal. This proposal investigates how the metabolic rate of birds and of their cells relates to their longevity. The authors will study underlying mechanisms for differences that they have identified in whole-animal metabolism between tropical and temperate birds, species assemblages with well-documented, distinct, life-histories including life-span. They show that tropical birds have low rates of basal and peak metabolism and that this is related to long life span and low rates of reproduction, which contrasts with temperate birds which have high rates of metabolism, high rates of reproduction, all associated with high rates of mortality. The authors use an integrated approach that focuses on identifying mechanisms at the whole-organism, cellular, and molecular levels that can account for the differences in life-histories such as longevity. The project employs phylogenetically-paired comparisons of tropical and temperate birds, which factors out phylogeny and body mass from analyses, to investigate differences in intrinsic properties of cells between tropical and temperate birds, such as their cellular metabolic rates, their resistance to oxidative stress and heavy metal toxicity, and membrane lipid peroxidation. Further the investigators examine the kinds of lipids and their degree of unsaturation in cell membranes using mass spectrometry because lipid unsaturation has been related to the aging process. This investigation will train a postdoctoral fellow, and will yield insights into how cell membranes might be altered to influence life-span.