P3.169 Friday, Jan. 6 Lipids of mitochondria in fibroblasts and their nexus to life history in temperate and tropical birds CALHOON, E.A.*; HARPER, J.M.; JIMENEZ, A.G.; MILLER, R.A.; JURKOWITZ, M.S.; WILLIAMS, J.B.; Ohio State University; Michigan State University; Ohio State University; Michigan State University; Ohio State University; Ohio State University email@example.com
Life history attributes often fall along a “slow-fast” continuum. Temperate birds are thought to have a fast pace of life whereas tropical birds have a slow pace of life. In support of this idea, tropical birds have lower metabolic rate, invest fewer resources in reproduction, and have higher adult survival rates compared with temperate birds. These organismal differences may be rooted in differences in the cellular level, a hypothesis in need of testing. Here, we cultured fibroblasts of phylogenetically-paired tropical and temperate species, isolated mitochondria from each, and compared their mitochondrial membrane lipids. We found that mitochondria from tropical species had higher amounts of lipids that could serve as an antioxidant, especially plasmalogens. Additionally, multiple proxies for amount of mitochondria suggested that large tropical species have fewer mitochondria than large temperate ones, whereas small tropical and temperate species have similar amounts. We examined the lethal dose of xenobiotics required to kill 50% of fibroblast cells (LD50) from tropical and temperate species and related LD50 to lipid composition of mitochondrial membranes. We found that lipids associated with preventing oxidative damage, such as plasmalogens, or with anti-apoptotic signaling were correlated with increased cellular stress resistance, whereas lipids that were associated with pro-apoptotic signaling were correlated with decreased stress resistance. These findings suggest that mitochondrial lipid composition could play an important role in cellular stress resistance and senescence.