| dc.description.abstract | The structure of cholesterol and ergosterol are similar, whereas the effect of cholesterol and ergosterol on lipid bilayer is different. Some cell membranes contain both cholesterol and ergosterol, such as the mitochondria of Saccharomyces cerevisiae. How ergosterol affects the properties cholesterol-containing lipid bilayers is of interest. In this work, we have studied the physical properties of model membranes containing unsaturated lipid, saturated lipid, cholesterol, and ergosterol using deuterium nuclear magnetic resonance (2H-NMR) and fluorescence microscopy.In the NMR experiment, unsaturated lipids were deuterium labeled. The phase behavior and membrane order then can be observed.The morphology of model membranes was observed by fluorescence microscopy. The fluorescent probe NBD-DOPE, presumably participate into the disordered phases, is used.The measurements were performed as a function of cholesterol/ergosterol molar ratio by fixing the molar ratio of unsaturated to saturated lipids.The measurements were also performed as a function of temperature. Addition of ergosterol to the cholesterol-containing lipid bilayers, which is in the lo phase for a given temperature,produces the ld phase. The fraction of the ld phase increases as the ergosterol increases, resulting in the decrease of membrane order. Furthermore, it is observed that for each membrane composition, the membrane order decreases with increasing temperature. | en_US |