Lipid rafts are a dynamic microdomain structure found in recent years, enriched in sphin- golipids, cholesterol and particular proteins. The change of structure and function of lipid rafts could result in many disease...Lipid rafts are a dynamic microdomain structure found in recent years, enriched in sphin- golipids, cholesterol and particular proteins. The change of structure and function of lipid rafts could result in many diseases. In this work, the monolayer miscibility behavior of mixed systems of Egg-Sphingomyelin （ESM） with 1, 2-dioleoyl-sn-glycero-3-phosphocholine was in- vestigated in terms of mean surface area per molecule and excess molecular area AAex at certain surface pressure, surface pressure and excess surface pressure Arcex at certain mean molecular area. The stability and compressibility of the mixed monolayers was assessed by the parameters of surface excess Gibbs free energy AGex, excess Helmholtz energy AHex and elasticity. Thermodynamic analysis indicates AAex and ATrex in the binary systems with positive deviations from the ideal behavior, suggesting repulsive interaction. The max- imum of AGex and AHex was at the molar fraction of ESM of 0.6, demonstrating the mixed monolayer was more unstable. The repulsive interaction induced phase separation in the monolayer.展开更多
Aim To explore interaction mode between amphoteric molecules with the orderedphospholipid membrane. Methods Membrane interactions were determined by immobilized artificialmembrane (IAM) chromatography and solutes'...Aim To explore interaction mode between amphoteric molecules with the orderedphospholipid membrane. Methods Membrane interactions were determined by immobilized artificialmembrane (IAM) chromatography and solutes' hydrophobicity was measured by n-octanol/buffer system.Results The ampholytes, similar to bases, generally exhibited higher membrane affinity than expectedfrom their hydrophobicity, resulting from the attractive polar interaction with phospholipidmembrane. Furthermore, the strength of additional polar interaction with membrane (Δlg k_(IAM)) wasthen calculated. The Δlg k_(IAM) values were far greater for bases and ampholytes ranging from0.50 - 1.39, than those for acids and neutrals with the scope from - 0.55 - 0.44. ConclusionConsidering the microspecies distribution of amphoteric molecules, it was assumed that not onlyneutral and positive but also zwitterionic microspecies are capable of partitioning into orderedamphoteric lipid membrane with complementarily conformational and energetically favorableinteractions.展开更多
The analysis of cellular lipids and phospholipids has been of continuously increasing research interest due to the importance of these molecules in psychological process.In this work,a mass spectrometry-based method f...The analysis of cellular lipids and phospholipids has been of continuously increasing research interest due to the importance of these molecules in psychological process.In this work,a mass spectrometry-based method for direct,in situ analysis of lipids in cells was reported.Mammalian cells were directly cultured on ITO-coated glass and then analyzed by matrix-assisted laser desorption ionization-mass spectrometry(MALDI-MS).The matrix application process was achieved by electrospray coating,which produced a homogenous layer of matrix crystal on the sample.The detection results and reproducibility are satisfactory.With this method,a profile of abundant membrane lipids is generated,which is characteristic of cell type.In conclusion,this in situ MALDI-MS cellular lipid analysis method provides a platform for sensitive and robust molecular profiling of mammalian cells.展开更多
N-budding lipid vesicles with single holes were analyzed theoretically by taking into account the line tension of membrane with a hole and the bending energy of membranes based on the Spontaneous-Curvature (SC) model....N-budding lipid vesicles with single holes were analyzed theoretically by taking into account the line tension of membrane with a hole and the bending energy of membranes based on the Spontaneous-Curvature (SC) model. We solved numerically the Euler-Lagrange equation and the boundary conditions holding on the membrane edge to obtain axisymmetric vesicle shapes, which minimize the total energy. The numerical results show that the size of the opening-up vesicle is larger when the line tension is lower. In other words, additive protein molecules reduce the line tension of lipid membranes, such as talin dose.展开更多
文摘Lipid rafts are a dynamic microdomain structure found in recent years, enriched in sphin- golipids, cholesterol and particular proteins. The change of structure and function of lipid rafts could result in many diseases. In this work, the monolayer miscibility behavior of mixed systems of Egg-Sphingomyelin （ESM） with 1, 2-dioleoyl-sn-glycero-3-phosphocholine was in- vestigated in terms of mean surface area per molecule and excess molecular area AAex at certain surface pressure, surface pressure and excess surface pressure Arcex at certain mean molecular area. The stability and compressibility of the mixed monolayers was assessed by the parameters of surface excess Gibbs free energy AGex, excess Helmholtz energy AHex and elasticity. Thermodynamic analysis indicates AAex and ATrex in the binary systems with positive deviations from the ideal behavior, suggesting repulsive interaction. The max- imum of AGex and AHex was at the molar fraction of ESM of 0.6, demonstrating the mixed monolayer was more unstable. The repulsive interaction induced phase separation in the monolayer.
文摘Aim To explore interaction mode between amphoteric molecules with the orderedphospholipid membrane. Methods Membrane interactions were determined by immobilized artificialmembrane (IAM) chromatography and solutes' hydrophobicity was measured by n-octanol/buffer system.Results The ampholytes, similar to bases, generally exhibited higher membrane affinity than expectedfrom their hydrophobicity, resulting from the attractive polar interaction with phospholipidmembrane. Furthermore, the strength of additional polar interaction with membrane (Δlg k_(IAM)) wasthen calculated. The Δlg k_(IAM) values were far greater for bases and ampholytes ranging from0.50 - 1.39, than those for acids and neutrals with the scope from - 0.55 - 0.44. ConclusionConsidering the microspecies distribution of amphoteric molecules, it was assumed that not onlyneutral and positive but also zwitterionic microspecies are capable of partitioning into orderedamphoteric lipid membrane with complementarily conformational and energetically favorableinteractions.
基金supported by the National Natural Science Foundation of China(21227006,21275088)
文摘The analysis of cellular lipids and phospholipids has been of continuously increasing research interest due to the importance of these molecules in psychological process.In this work,a mass spectrometry-based method for direct,in situ analysis of lipids in cells was reported.Mammalian cells were directly cultured on ITO-coated glass and then analyzed by matrix-assisted laser desorption ionization-mass spectrometry(MALDI-MS).The matrix application process was achieved by electrospray coating,which produced a homogenous layer of matrix crystal on the sample.The detection results and reproducibility are satisfactory.With this method,a profile of abundant membrane lipids is generated,which is characteristic of cell type.In conclusion,this in situ MALDI-MS cellular lipid analysis method provides a platform for sensitive and robust molecular profiling of mammalian cells.
基金supported by the National Natural Science Foundation of China (Grant no.10374063)
文摘N-budding lipid vesicles with single holes were analyzed theoretically by taking into account the line tension of membrane with a hole and the bending energy of membranes based on the Spontaneous-Curvature (SC) model. We solved numerically the Euler-Lagrange equation and the boundary conditions holding on the membrane edge to obtain axisymmetric vesicle shapes, which minimize the total energy. The numerical results show that the size of the opening-up vesicle is larger when the line tension is lower. In other words, additive protein molecules reduce the line tension of lipid membranes, such as talin dose.
