| Summary: | 碩士 === 國立中央大學 === 生物物理研究所 === 100 === The biological membrane has a feature of lateral heterogeneities. The feature is proposed to be a coexistence of domains which termed lipid rafts with different physical and chemical properties. Lipid rafts are enriched in cholesterol, sphingolipid, and GPI-anchored proteins. Recent evidence suggests that several sterols such as cholesterol and ergosterol are important to form liquid ordered phase (lo phase) in the lipid bilayer. Also, there are seven kinds of phases and coexistence phases are observed by the giant unilamellar vesicles (GUV) composed of DOPC, DPPC, and cholesterol. We investigate the membrane morphology and phase behavior of GUVs composed of DOPC, DPPC, and ergosterol using fluorescence microscopy. The NBD-DOPE is used to be a fluorescent probe to label the liquid disordered phase (ld phase). The fluorescent images of GUVs were studied as a function of temperature and composition. By analyzing the shape of dark-phase domains in the fluorescent image, we generalize the dark micro and dark macro regions are both in the lo phase, however the lo phase in the dark macro region is slightly ordered than that in the dark micro region. Our data shows that addition of ergosterol promotes the formation of lo phase. Moreover, coexistence of ld + lo1 + lo2 phase is observed.
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