Meeting Abstract
Temperate birds tend to have a fast pace of life, having short life-spans with high reproductive output and high metabolic rate, whereas tropical birds tend to have a slower pace of life, investing fewer resources in reproduction and having higher adult survival rates with lower metabolic rates. How these differences in life history at the organismal level are rooted in differences at the cellular level is a focus of current research. Increases in the saturation level of fatty acids in the phospholipids of cell membranes has been implicated in decreasing metabolic rate and oxidative stress, but this connection has been challenged and its validity may depend on which organelle the increase in saturation is in. Several studies have looked at the fatty acid content of phospholipids in whole cells and in mitochondria, but none have compared the effects of different saturation levels between mitochondrial and non-mitochondrial membranes on metabolic rate. Here, we cultured fibroblasts from phylogenetically-paired tropical and temperate bird species, isolated the mitochondria from the other organelles, and then compared mitochondrial and non-mitochondrial membrane lipids between tropical and temperate birds using high-performance liquid chromatography-mass spectrometry. Additionally, previous studies in our lab have measured the metabolic rate of the same cell lines, so we were also able to compare the effects of mitochondrial and non-mitochondrial phospholipid fatty acid composition on cellular metabolic rates.
