Meeting Abstract
Lipids, the defining feature of biological membranes, allow cells to remain viable across varying temperatures through changes in membrane fluidity, the extent of disorder in the lipid bilayer. At high temperatures, lipid tails are long and saturated, stabilizing the membrane in a liquid-solid phase. As temperature decreases, double bonds in acyl chains produce kinks in lipid tails, stabilizing the membrane in a solid-liquid phase. Membrane fluidity further affects the functions of proteins in the bilayer, altering critical cellular functions. However, little research has addressed how temperature differences within and across species affects lipid composition and membrane fluidity in the brain. Here, we test whether lizards that experience similar temperatures maintain similar membrane fluidity by adjusting the ratio of specific membrane lipids. First, we performed a field study comparing brain lipid composition in seven Puerto Rican Anolis species in habitats of varying temperature. Next, we conducted a laboratory experiment in which Anolis carolinensis lizards were housed in a hot (34°C) or cool (26°C) room to directly determine how temperature influences brain lipid content. In both studies, we use qualitative mass spectroscopy analysis of cell membrane extracts from whole brains to describe lipid composition as a function of temperature. Lastly, we cultured astrocytes from A. carolinensis brains at 28°C and 35°C to measure differences in cell growth and lipid synthesis, and to directly quantify plasma membrane fluidity by fluorescent polarization. Results show that cells at 28°C grow more rapidly, and the abundance of lipid droplets in the cells varies with temperature. Together, these results will improve our understanding of how organisms respond to a rapidly changing environment.
