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Peter J Quinn - One of the best experts on this subject based on the ideXlab platform.
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The effect of dolichol on the structure and phase behaviour of phospholipid model membranes.
Molecular Membrane Biology, 2008Co-Authors: Xiaoyuan Wang, Azad Reza Mansourian, Peter J QuinnAbstract:The effect of dolichol C95 on the structure and thermotropic phase behaviour of dipalmitoylphosphatidylcholine, Dipalmitoylphosphatidylethanolamine and stearoyloleoylphosphatidylethanolamine has been examined by synchrotron X-ray diffraction and differential scanning calorimetry. The presence of dolichol C95 had no detectible effects on the temperature of either the gel to ripple or the ripple to liquid-crystal phase transition of dipalmitoylphosphatidylcholine. A proportionate increase of a few degrees in the temperature of the gel to lamellar liquid-crystal phase transition is observed in dispersions of Dipalmitoylphosphatidylethanolamine and significantly there is a decrease in the temperature of the lamellar to non-lamellar phase transition of stearoyloleoylphosphatidylethanolamine. There was no significant change in the bilayer repeat spacing of all three mixed dispersions in gel phase in the presence of up to 20 mol% dolichol C95. Electron density calculations showed that there was no change of bila...
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phase behavior of Dipalmitoylphosphatidylethanolamine in dimethylsulfoxide water mixture
Thermochimica Acta, 2004Co-Authors: Lin Chen, Zhiwu Yu, Ying Feng, Peter J QuinnAbstract:Abstract The phase behaviors of Dipalmitoylphosphatidylethanolamine (DPPE) dispersed in dimethyl sulfoxide (DMSO) aqueous solutions were studied by using differential scanning calorimetry and X-ray diffraction methods. At low concentration of DMSO (mole fraction, x −1 . The formation of the stable lamellar-crystal phase from the metastable lamellar-gel phase needs long time incubation. At moderate concentration of DMSO (0.2 x x >0.37), DMSO promotes remarkably the formation of lamellar-crystal phase of the lipid, resulting in phase transitions between lamellar-crystal phase and liquid-crystal phase during heating/cooling cycling. A phase diagram has been constructed over the entire concentration range of the mixed solvent. In addition, it was found that DMSO could decrease the lamellar repeat spacing of crystalline and liquid crystalline phase.
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Phase behavior of Dipalmitoylphosphatidylethanolamine in dimethylsulfoxide–water mixture ☆
Thermochimica Acta, 2004Co-Authors: Lin Chen, Zhiwu Yu, Ying Feng, Peter J QuinnAbstract:Abstract The phase behaviors of Dipalmitoylphosphatidylethanolamine (DPPE) dispersed in dimethyl sulfoxide (DMSO) aqueous solutions were studied by using differential scanning calorimetry and X-ray diffraction methods. At low concentration of DMSO (mole fraction, x −1 . The formation of the stable lamellar-crystal phase from the metastable lamellar-gel phase needs long time incubation. At moderate concentration of DMSO (0.2 x x >0.37), DMSO promotes remarkably the formation of lamellar-crystal phase of the lipid, resulting in phase transitions between lamellar-crystal phase and liquid-crystal phase during heating/cooling cycling. A phase diagram has been constructed over the entire concentration range of the mixed solvent. In addition, it was found that DMSO could decrease the lamellar repeat spacing of crystalline and liquid crystalline phase.
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the kinetics and mechanism of the formation of crystalline phase of Dipalmitoylphosphatidylethanolamine dispersed in aqueous dimethyl sulfoxide solutions
Chemistry and Physics of Lipids, 2004Co-Authors: Lin Chen, Zhiwu Yu, Peter J QuinnAbstract:The phase transition kinetics and mechanism of formation of a lamellar-crystalline phase of Dipalmitoylphosphatidylethanolamine (DPPE) dispersed in different concentrations of aqueous dimethyl sulfoxide (DMSO) during cooling have been examined by differential scanning calorimetry and synchrotron X-ray diffraction techniques. In dispersions containing mole fractions of DMSO ( x 0.5 resulted in a direct transition from liquid-crystal phase to lamellar crystal phase with no detectable intermediate gel phase. A temperature versus DMSO concentration phase diagram was constructed based on calorimetric data with phase assignments made using synchrotron X-ray diffraction measurements. The non-isothermal formation kinetics of the lamellar crystal phase, which is expressed as the half time of the transformation process, was found to depend on DMSO concentration. The inducement of lamellar crystal phase in DPPE by DMSO is discussed in terms of the dehydration effect of DMSO and competitive molecular interactions between DMSO, water, and the phospholipid. © 2003 Elsevier Ireland Ltd. All rights reserved.
Lin Chen - One of the best experts on this subject based on the ideXlab platform.
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phase behavior of Dipalmitoylphosphatidylethanolamine in dimethylsulfoxide water mixture
Thermochimica Acta, 2004Co-Authors: Lin Chen, Zhiwu Yu, Ying Feng, Peter J QuinnAbstract:Abstract The phase behaviors of Dipalmitoylphosphatidylethanolamine (DPPE) dispersed in dimethyl sulfoxide (DMSO) aqueous solutions were studied by using differential scanning calorimetry and X-ray diffraction methods. At low concentration of DMSO (mole fraction, x −1 . The formation of the stable lamellar-crystal phase from the metastable lamellar-gel phase needs long time incubation. At moderate concentration of DMSO (0.2 x x >0.37), DMSO promotes remarkably the formation of lamellar-crystal phase of the lipid, resulting in phase transitions between lamellar-crystal phase and liquid-crystal phase during heating/cooling cycling. A phase diagram has been constructed over the entire concentration range of the mixed solvent. In addition, it was found that DMSO could decrease the lamellar repeat spacing of crystalline and liquid crystalline phase.
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Phase behavior of Dipalmitoylphosphatidylethanolamine in dimethylsulfoxide–water mixture ☆
Thermochimica Acta, 2004Co-Authors: Lin Chen, Zhiwu Yu, Ying Feng, Peter J QuinnAbstract:Abstract The phase behaviors of Dipalmitoylphosphatidylethanolamine (DPPE) dispersed in dimethyl sulfoxide (DMSO) aqueous solutions were studied by using differential scanning calorimetry and X-ray diffraction methods. At low concentration of DMSO (mole fraction, x −1 . The formation of the stable lamellar-crystal phase from the metastable lamellar-gel phase needs long time incubation. At moderate concentration of DMSO (0.2 x x >0.37), DMSO promotes remarkably the formation of lamellar-crystal phase of the lipid, resulting in phase transitions between lamellar-crystal phase and liquid-crystal phase during heating/cooling cycling. A phase diagram has been constructed over the entire concentration range of the mixed solvent. In addition, it was found that DMSO could decrease the lamellar repeat spacing of crystalline and liquid crystalline phase.
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the kinetics and mechanism of the formation of crystalline phase of Dipalmitoylphosphatidylethanolamine dispersed in aqueous dimethyl sulfoxide solutions
Chemistry and Physics of Lipids, 2004Co-Authors: Lin Chen, Zhiwu Yu, Peter J QuinnAbstract:The phase transition kinetics and mechanism of formation of a lamellar-crystalline phase of Dipalmitoylphosphatidylethanolamine (DPPE) dispersed in different concentrations of aqueous dimethyl sulfoxide (DMSO) during cooling have been examined by differential scanning calorimetry and synchrotron X-ray diffraction techniques. In dispersions containing mole fractions of DMSO ( x 0.5 resulted in a direct transition from liquid-crystal phase to lamellar crystal phase with no detectable intermediate gel phase. A temperature versus DMSO concentration phase diagram was constructed based on calorimetric data with phase assignments made using synchrotron X-ray diffraction measurements. The non-isothermal formation kinetics of the lamellar crystal phase, which is expressed as the half time of the transformation process, was found to depend on DMSO concentration. The inducement of lamellar crystal phase in DPPE by DMSO is discussed in terms of the dehydration effect of DMSO and competitive molecular interactions between DMSO, water, and the phospholipid. © 2003 Elsevier Ireland Ltd. All rights reserved.
Shoji Kaneshina - One of the best experts on this subject based on the ideXlab platform.
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Effect of pressure on the bilayer phase transitions of N-methylated Dipalmitoylphosphatidylethanolamines
Progress in Biotechnology, 2014Co-Authors: Hitoshi Matsuki, Masataka Kusube, Hayato Ichimori, Shoji KaneshinaAbstract:The main-transition temperatures between gel and liquid crystalline phases for dipalmitoylphosphatidylmonomethylethanolamine (DPMePE) and dipalmitoylphosphatidyldimethylethanolamine (DPMe2PE) under high pressure were determined from differential scanning calorimetry (DSC) and optical methods. The thermodynamic quantities of main transition (enthalpy, entropy, and volume) were calculated and the results were compared with those of Dipalmitoylphosphatidylethanolamine (DPPE) and dipalmitoylphosphatidylcholine (DPPC) to clarify the effect of N-methylation of DPPE on the main transition. The main-transition temperatures of N-methylated DPPEs increased linearly by applying pressure while they decreased with increasing the size of head group by stepwise N-methylation. On the other hand, there was no significant difference in thermodynamic quantities between the phospholipids. The difference in hydrophilic interactions between the different-sized polar head groups produces a great difference on the main-transition temperature and the packing arrangement of bilayer membrane in the gel phase.
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thermotropic and barotropic phase transitions of n methylated Dipalmitoylphosphatidylethanolamine bilayers
Biochimica et Biophysica Acta, 2005Co-Authors: Masataka Kusube, Hitoshi Matsuki, Shoji KaneshinaAbstract:: In order to understand the effect of polar head group modification on the thermotropic and barotropic phase behavior of phospholipid bilayer membranes, the phase transitions of Dipalmitoylphosphatidylethanolamine (DPPE), dipalmitoylphosphatidyl-N-methylethanolamine (DPMePE), dipalmitoylphosphatidyl-N,N-dimethylethanolamine (DPMe2PE) and dipalmitoylphosphatidylcholine (DPPC) bilayer membranes were observed by differential scanning calorimetry and high-pressure optical methods. The temperatures of the so-called main transition from the gel (L(beta)) or ripple gel (P(beta)') phase to the liquid crystalline (L(alpha)) phase were almost linearly elevated by applying pressure. The slope of the temperature-pressure boundary, dT/dp, was in the range of 0.220-0.264 K MPa(-1) depending on the number of methyl groups in the head group of lipids. The main-transition temperatures of N-methylated DPPEs decreased with increasing size of head group by stepwise N-methylation. On the other hand, there was no significant difference in thermodynamic quantities of the main transition between the phospholipids. With respect to the transition from the subgel (L(c)) phase to the lamellar gel (L(beta) or L(beta)') phase, the transition temperatures were also elevated by applying pressure. In the case of DPPE bilayer the L(c)/L(beta) transition appeared at a pressure higher than 21.8 MPa. At a pressure below 21.8 MPa the L(c)/L(alpha) transition was observed at a temperature higher than the main-transition temperature. The main (L(beta)/L(alpha)) transition can be recognized as the transformation between metastable phases in the range from ambient pressure to 21.8 MPa. Polymorphism in the gel phase is characteristic of DPPC bilayer membrane unlike other lipid bilayers used in this study: the L(beta)', P(beta)' and pressure-induced interdigitated gel (L(beta)I) phases were observed only in the DPPC bilayer. Regarding the bilayers of DPPE, DPMePE and DPMe2PE, the interdigitation of acyl chain did not appear even at pressures as high as 200 MPa.
Zhiwu Yu - One of the best experts on this subject based on the ideXlab platform.
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phase behavior of Dipalmitoylphosphatidylethanolamine in dimethylsulfoxide water mixture
Thermochimica Acta, 2004Co-Authors: Lin Chen, Zhiwu Yu, Ying Feng, Peter J QuinnAbstract:Abstract The phase behaviors of Dipalmitoylphosphatidylethanolamine (DPPE) dispersed in dimethyl sulfoxide (DMSO) aqueous solutions were studied by using differential scanning calorimetry and X-ray diffraction methods. At low concentration of DMSO (mole fraction, x −1 . The formation of the stable lamellar-crystal phase from the metastable lamellar-gel phase needs long time incubation. At moderate concentration of DMSO (0.2 x x >0.37), DMSO promotes remarkably the formation of lamellar-crystal phase of the lipid, resulting in phase transitions between lamellar-crystal phase and liquid-crystal phase during heating/cooling cycling. A phase diagram has been constructed over the entire concentration range of the mixed solvent. In addition, it was found that DMSO could decrease the lamellar repeat spacing of crystalline and liquid crystalline phase.
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Phase behavior of Dipalmitoylphosphatidylethanolamine in dimethylsulfoxide–water mixture ☆
Thermochimica Acta, 2004Co-Authors: Lin Chen, Zhiwu Yu, Ying Feng, Peter J QuinnAbstract:Abstract The phase behaviors of Dipalmitoylphosphatidylethanolamine (DPPE) dispersed in dimethyl sulfoxide (DMSO) aqueous solutions were studied by using differential scanning calorimetry and X-ray diffraction methods. At low concentration of DMSO (mole fraction, x −1 . The formation of the stable lamellar-crystal phase from the metastable lamellar-gel phase needs long time incubation. At moderate concentration of DMSO (0.2 x x >0.37), DMSO promotes remarkably the formation of lamellar-crystal phase of the lipid, resulting in phase transitions between lamellar-crystal phase and liquid-crystal phase during heating/cooling cycling. A phase diagram has been constructed over the entire concentration range of the mixed solvent. In addition, it was found that DMSO could decrease the lamellar repeat spacing of crystalline and liquid crystalline phase.
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the kinetics and mechanism of the formation of crystalline phase of Dipalmitoylphosphatidylethanolamine dispersed in aqueous dimethyl sulfoxide solutions
Chemistry and Physics of Lipids, 2004Co-Authors: Lin Chen, Zhiwu Yu, Peter J QuinnAbstract:The phase transition kinetics and mechanism of formation of a lamellar-crystalline phase of Dipalmitoylphosphatidylethanolamine (DPPE) dispersed in different concentrations of aqueous dimethyl sulfoxide (DMSO) during cooling have been examined by differential scanning calorimetry and synchrotron X-ray diffraction techniques. In dispersions containing mole fractions of DMSO ( x 0.5 resulted in a direct transition from liquid-crystal phase to lamellar crystal phase with no detectable intermediate gel phase. A temperature versus DMSO concentration phase diagram was constructed based on calorimetric data with phase assignments made using synchrotron X-ray diffraction measurements. The non-isothermal formation kinetics of the lamellar crystal phase, which is expressed as the half time of the transformation process, was found to depend on DMSO concentration. The inducement of lamellar crystal phase in DPPE by DMSO is discussed in terms of the dehydration effect of DMSO and competitive molecular interactions between DMSO, water, and the phospholipid. © 2003 Elsevier Ireland Ltd. All rights reserved.
Francoise Nepveu - One of the best experts on this subject based on the ideXlab platform.
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edta and dtpa analogues of Dipalmitoylphosphatidylethanolamine as lipopphilic chelating agents for metal labeling of ldl
Tetrahedron Letters, 1996Co-Authors: Pascale Urizzi, Jeanpierre Souchard, Francoise NepveuAbstract:Abstract Two lipophilic chelating agents (L) prepared by reaction of Dipalmitoylphosphatidylethanolamine with the bis(anhydride) form of ethylenediaminetetraacetic acid (EDTA) or diethylenetriaminepentaacetic acid (DTPA) were characterized. L, indium-L or gadolinium-L complexes are soluble in buffered solutions and may be used for metal labeling of LDL.