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Magnesium Trimethoxyphenylporphyrin Chain Controls Energy Dissipation in the presence of Cholesterol. J CHEM SCI 2017. [DOI: 10.1007/s12039-017-1251-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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2
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Bagatolli LA, Needham D. Quantitative optical microscopy and micromanipulation studies on the lipid bilayer membranes of giant unilamellar vesicles. Chem Phys Lipids 2014; 181:99-120. [PMID: 24632023 DOI: 10.1016/j.chemphyslip.2014.02.009] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Revised: 02/25/2014] [Accepted: 02/26/2014] [Indexed: 12/01/2022]
Abstract
This manuscript discusses basic methodological aspects of optical microscopy and micromanipulation methods to study membranes and reviews methods to generate giant unilamellar vesicles (GUVs). In particular, we focus on the use of fluorescence microscopy and micropipet manipulation techniques to study composition-structure-property materials relationships of free-standing lipid bilayer membranes. Because their size (∼5-100 μm diameter) that is well above the resolution limit of regular light microscopes, GUVs are suitable membrane models for optical microscopy and micromanipulation experimentation. For instance, using different fluorescent reporters, fluorescence microscopy allows strategies to study membrane lateral structure/dynamics at the level of single vesicles of diverse compositions. The micropipet manipulation technique on the other hand, uses Hoffman modulation contrast microscopy and allows studies on the mechanical, thermal, molecular exchange and adhesive-interactive properties of compositionally different membranes under controlled environmental conditions. The goal of this review is to (i) provide a historical perspective for both techniques; (ii) present and discuss some of their most important contributions to our understanding of lipid bilayer membranes; and (iii) outline studies that would utilize both techniques simultaneously on the same vesicle thus bringing the ability to characterize structure and strain responses together with the direct application of well-defined stresses to a single membrane or observe the effects of adhesive spreading. Knowledge gained by these studies has informed several applications of lipid membranes including their use as lung surfactants and drug delivery systems for cancer.
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Affiliation(s)
- Luis A Bagatolli
- Membrane Biophysics and Biophotonics Group/MEMPHYS - Center for Biomembrane Physics, Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark.
| | - David Needham
- DNRF Niels Bohr Professorship, Center for Single Particle Science and Engineering, Institute for Physics, Chemistry and Pharmacy, University of Southern Denmark, Odense, Denmark; Department of Mechanical Engineering and Material Science, Duke University, Durham, NC, USA
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Garidel P, Johann C, Blume A. Non-ideal mixing and fluid–fluid immiscibility in phosphatidic acid–phosphatidylethanolamine mixed bilayers. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2011; 40:891-905. [DOI: 10.1007/s00249-011-0707-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2010] [Revised: 04/08/2011] [Accepted: 04/27/2011] [Indexed: 01/12/2023]
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4
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Luisetti J, Galla HJ, Möhwald H. Energy Transfer and Fluorescence Quenching in Chlorophyll Containing Vesicles. ACTA ACUST UNITED AC 2010. [DOI: 10.1002/bbpc.19780820930] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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5
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Akbarieh M, Besner JG, Galal A, Tawashi R. Liposomal delivery system for the targeting and controlled release of praziquantel. Drug Dev Ind Pharm 2008. [DOI: 10.3109/03639049209043701] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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6
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Garidel P, Johann C, Blume A. Thermodynamics of Lipid Organization and Domain Formation in Phospholipid Bilayers. J Liposome Res 2008. [DOI: 10.3109/08982100009029383] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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7
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Ford WE, Tollin G. CHLOROPHYLL PHOTOSENSITIZED ELECTRON TRANSFER IN PHOSPHOLIPID BILAYER VESICLE SYSTEMS: EFFECTS OF CHOLESTEROL ON RADICAL YIELDS AND KINETIC PARAMETERS*. Photochem Photobiol 2008. [DOI: 10.1111/j.1751-1097.1984.tb04583.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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8
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Nibu Y, Inoue T, Motoda I. Effect of headgroup type on the miscibility of homologous phospholipids with different acyl chain lengths in hydrated bilayer. Biophys Chem 2007; 56:273-80. [PMID: 17023328 DOI: 10.1016/0301-4622(95)00041-u] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/1994] [Revised: 02/27/1995] [Accepted: 02/28/1995] [Indexed: 11/21/2022]
Abstract
The miscibility of homologous phosphatidylcholines with different acyl chain lengths in hydrated bilayer was examined through the binary phase diagram constructed by differential scanning calorimetry. By analyzing the phase diagram according to a thermodynamic model based on the Bragg-Williams approximation to evaluate the excess free energy of mixing, the non-ideality parameter of mixing, rho(0), was estimated, which allows one to interpret the mixing behavior of the two lipid components in terms of the difference in the pair-interaction energies between like-pairs and mixed-pairs formed in the mixture. By summarizing the rho(0) values obtained previously for other classes of phospholipids, it was found that rho(0) increases in the order of phosphatidylglycerol (PG) approximately phosphatidylcholine (PC) < phosphatidylethanolamine (PE) < phosphatidic acid (PA). Since the difference in the pair-interaction energies is considered to be determined by the relative contribution of inter-headgroup interaction to the overall intermolecular interaction, this sequence of rho(0) value suggests that the headgroup interaction in hydrated bilayer increases in the order of PA < PE < PC approximately PG.
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Affiliation(s)
- Y Nibu
- Department of Chemistry, Faculty of Science, Fukuoka University, Nanakuma, Jonan-ku, Fukuoka 814-01, Japan
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9
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Bagatolli LA. To see or not to see: Lateral organization of biological membranes and fluorescence microscopy. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2006; 1758:1541-56. [PMID: 16854370 DOI: 10.1016/j.bbamem.2006.05.019] [Citation(s) in RCA: 283] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2006] [Revised: 05/14/2006] [Accepted: 05/19/2006] [Indexed: 12/15/2022]
Abstract
In the last few years several experimental strategies based on epi-, confocal and two photon excitation fluorescence microscopy techniques have been employed to study the lateral structure of membranes using giant vesicles as model systems. This review article discusses the methodological aspects of the aforementioned experimental approaches, particularly stressing the information obtained by the use of UV excited fluorescent probes using two-photon excitation fluorescence microscopy. Additionally, the advantages of utilizing visual information, to correlate the lateral structure of compositionally simple membranes with complex situations, i.e., biological membranes, will be addressed.
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Affiliation(s)
- Luis A Bagatolli
- MEMPHYS - Center for Biomembrane Physics, Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark.
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10
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Veatch SL, Keller SL. Seeing spots: Complex phase behavior in simple membranes. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2005; 1746:172-85. [PMID: 16043244 DOI: 10.1016/j.bbamcr.2005.06.010] [Citation(s) in RCA: 561] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2005] [Revised: 05/27/2005] [Accepted: 06/20/2005] [Indexed: 12/11/2022]
Abstract
Liquid domains in model lipid bilayers are frequently studied as models of raft domains in cell plasma membranes. Micron-scale liquid domains are easily produced in vesicles composed of ternary mixtures of a high melting temperature lipid, a low melting temperature lipid, and cholesterol. Here, we describe the rich phase behavior observed in binary and ternary systems. We then discuss experimental challenges inherent in mapping phase diagrams of even simple lipid systems. For example, miscibility behavior varies with lipid type, lipid ratio, lipid oxidation, and level of impurity. Liquid domains are often circular, but can become noncircular when membranes are near critical points. Finally, we reflect on applications of phase diagrams in model systems to rafts in cell membranes.
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Affiliation(s)
- Sarah L Veatch
- Department of Physics, University of Washington, Seattle WA 98195, USA.
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11
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Bagatolli LA, Sanchez SA, Hazlett T, Gratton E. Giant vesicles, Laurdan, and two-photon fluorescence microscopy: evidence of lipid lateral separation in bilayers. Methods Enzymol 2003; 360:481-500. [PMID: 12622164 DOI: 10.1016/s0076-6879(03)60124-2] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Luis A Bagatolli
- Department of Physics, MEMPHYS-Center for Biomembrane Physics, University of Southern Denmark, Odense
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12
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Bagatolli LA. Thermotropic behavior of lipid mixtures studied at the level of single vesicles: giant unilamellar vesicles and two-photon excitation fluorescence microscopy. Methods Enzymol 2003; 367:233-53. [PMID: 14611068 DOI: 10.1016/s0076-6879(03)67015-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Luis A Bagatolli
- Center for Biomembrane Physics, Department of Biochemistry and Molecular Biology, Campusvej 55, DK-5230 Odense M, Denmark
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13
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Bagatolli LA, Gratton E. A correlation between lipid domain shape and binary phospholipid mixture composition in free standing bilayers: A two-photon fluorescence microscopy study. Biophys J 2000; 79:434-47. [PMID: 10866969 PMCID: PMC1300947 DOI: 10.1016/s0006-3495(00)76305-3] [Citation(s) in RCA: 185] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Giant unilamellar vesicles (GUVs) composed of different phospholipid binary mixtures were studied at different temperatures, by a method combining the sectioning capability of the two-photon excitation fluorescence microscope and the partition and spectral properties of 6-dodecanoyl-2-dimethylamino-naphthalene (Laurdan) and Lissamine rhodamine B 1,2-dihexadecanoyl-sn-glycero-3-phosphoethanolamine (N-Rh-DPPE). We analyzed and compared fluorescence images of GUVs composed of 1,2-dilauroyl-sn-glycero-3-phosphocholine/1, 2-dipalmitoyl-sn-glycero-3-phosphocholine (DLPC/DPPC), 1, 2-dilauroyl-sn-glycero-3-phosphocholine/1, 2-distearoyl-sn-glycero-3-phosphocholine (DLPC/DSPC), 1, 2-dilauroyl-sn-glycero-3-phosphocholine/1, 2-diarachidoyl-sn-glycero-3-phosphocholine (DLPC/DAPC), 1, 2-dimyristoyl-sn-glycero-3-phosphocholine/1, 2-distearoyl-sn-glycero-3-phosphocholine (DMPC/DSPC) (1:1 mol/mol in all cases), and 1,2-dimyristoyl-sn-glycero-3-phosphoethanolamine/1, 2-dimyristoyl-sn-glycero-3-phosphocholine (DMPE/DMPC) (7:3 mol/mol) at temperatures corresponding to the fluid phase and the fluid-solid phase coexistence. In addition, we studied the solid-solid temperature regime for the DMPC/DSPC and DMPE/DMPC mixtures. From the Laurdan intensity images the generalized polarization function (GP) was calculated at different temperatures to characterize the phase state of the lipid domains. We found a homogeneous fluorescence distribution in the GUV images at temperatures corresponding to the fluid region for all of the lipid mixtures. At temperatures corresponding to phase coexistence we observed concurrent fluid and solid domains in the GUVs independent of the lipid mixture. In all cases the lipid solid domains expanded and migrated around the vesicle surface as we decreased the temperature. The migration of the solid domains decreased dramatically at temperatures close to the solid-fluid-->solid phase transition. For the DLPC-containing mixtures, the solid domains showed line, quasicircular, and dendritic shapes as the difference in the hydrophobic chain length between the components of the binary mixture increases. In addition, for the saturated PC-containing mixtures, we found a linear relationship between the GP values for the fluid and solid domains and the difference between the hydrophobic chain length of the binary mixture components. Specifically, at the phase coexistence temperature region the difference in the GP values, associated with the fluid and solid domains, increases as the difference in the chain length of the binary mixture component increases. This last finding suggests that in the solid-phase domains, the local concentration of the low melting temperature phospholipid component increases as the hydrophobic mismatch decreases. At the phase coexistence temperature regime and based on the Laurdan GP data, we observe that when the hydrophobic mismatch is 8 (DLPC/DAPC), the concentration of the low melting temperature phospholipid component in the solid domains is negligible. This last observation extends to the saturated PE/PC mixtures at the phase coexistence temperature range. For the DMPC/DSPC we found that the nonfluorescent solid regions gradually disappear in the solid temperature regime of the phase diagram, suggesting lipid miscibility. This last result is in contrast with that found for DMPE/DMPC mixtures, where the solid domains remain on the GUV surface at temperatures corresponding to that of the solid region. In all cases the solid domains span the inner and outer leaflets of the membrane, suggesting a strong coupling between the inner and outer monolayers of the lipid membrane. This last finding extends previous observations of GUVs composed of DPPE/DPPC and DLPC/DPPC mixtures (, Biophys. J. 78:290-305).
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Affiliation(s)
- L A Bagatolli
- Laboratory for Fluorescence Dynamics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801-3080, USA.
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14
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Stillwell W, Jenski LJ, Zerouga M, Dumaual AC. Detection of lipid domains in docasahexaenoic acid-rich bilayers by acyl chain-specific FRET probes. Chem Phys Lipids 2000; 104:113-32. [PMID: 10669305 DOI: 10.1016/s0009-3084(99)00122-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
A major problem in defining biological membrane structure is deducing the nature and even existence of lipid microdomains. Lipid microdomains have been defined operationally as heterogeneities in the behavior of fluorescent membrane probes, particularly the fluorescence resonance energy transfer (FRET) probes 7-nitrobenz-2-oxa-1,3-diazol-4-yl-diacyl-sn-glycero-3-phosphoethan olamine (N-NBD-PE) and (N-lissamine rhodamine B sulfonyl)-diacyl-snglycero-3-phosphoethanolamine (N-Rh-PE). Here we test a variety of N-NBD-PEs and N-Rh-PEs containing: (a) undefined acyl chains, (b) liquid crystalline- and gel-state acyl chains, and (c) defined acyl chains matching those of phase separated membrane lipids. The phospholipid bilayer systems employed represent a liquid crystalline/gel phase separation and a cholesterol-driven fluid/fluid phase separation; phase separation is confirmed by differential scanning calorimetry. We tested the hypothesis that acyl chain affinities may dictate the phase into which N-NBD-PE and N-Rh-PE FRET probes partition. While these FRET probes were largely successful at tracking liquid crystalline/gel phase separations, they were less useful in following fluid/fluid separations and appeared to preferentially partition into the liquid-disordered phase. Additionally, partition measurements indicate that the rhodamine-containing probes are substantially less hydrophobic than the analogous NBD probes. These experiments indicate that acyl chain affinities may not be sufficient to employ acyl chain-specific N-NBD-PE/N-Rh-PE FRET probes to investigate phase separations into biologically relevant fluid/fluid lipid microdomains.
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Affiliation(s)
- W Stillwell
- Department of Biology, Indiana University-Purdue University at Indianapolis, 46202-5132, USA.
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15
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Bagatolli LA, Gratton E. Two photon fluorescence microscopy of coexisting lipid domains in giant unilamellar vesicles of binary phospholipid mixtures. Biophys J 2000; 78:290-305. [PMID: 10620293 PMCID: PMC1300637 DOI: 10.1016/s0006-3495(00)76592-1] [Citation(s) in RCA: 297] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
Images of giant unilamellar vesicles (GUVs) formed by different phospholipid mixtures (1,2-dipalmitoyl-sn-glycero-3-phosphocholine/1, 2-dilauroyl-sn-glycero-3-phosphocholine (DPPC/DLPC) 1:1 (mol/mol), and 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine/1, 2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPE/DPPC), 7:3 and 3:7 (mol/mol) at different temperatures were obtained by exploiting the sectioning capability of a two-photon excitation fluorescence microscope. 6-Dodecanoyl-2-dimethylamino-naphthalene (LAURDAN), 6-propionyl-2-dimethylamino-naphthalene (PRODAN), and Lissamine rhodamine B 1,2-dihexadecanoyl-sn-glycero-3-phosphoethanolamine (N-Rh-DPPE) were used as fluorescent probes to reveal domain coexistence in the GUVs. We report the first characterization of the morphology of lipid domains in unsupported lipid bilayers. From the LAURDAN intensity images the excitation generalized polarization function (GP) was calculated at different temperatures to characterize the phase state of the lipid domain. On the basis of the phase diagram of each lipid mixture, we found a homogeneous fluorescence distribution in the GUV images at temperatures corresponding to the fluid region in all lipid mixtures. At temperatures corresponding to the phase coexistence region we observed lipid domains of different sizes and shapes, depending on the lipid sample composition. In the case of GUVs formed by DPPE/DPPC mixture, the gel DPPE domains present different shapes, such as hexagonal, rhombic, six-cornered star, dumbbell, or dendritic. At the phase coexistence region, the gel DPPE domains are moving and growing as the temperature decreases. Separated domains remain in the GUVs at temperatures corresponding to the solid region, showing solid-solid immiscibility. A different morphology was found in GUVs composed of DLPC/DPPC 1:1 (mol/mol) mixtures. At temperatures corresponding to the phase coexistence, we observed the gel domains as line defects in the GUV surface. These lines move and become thicker as the temperature decreases. As judged by the LAURDAN GP histogram, we concluded that the lipid phase characteristics at the phase coexistence region are different between the DPPE/DPPC and DLPC/DPPC mixtures. In the DPPE/DPPC mixture the coexistence is between pure gel and pure liquid domains, while in the DLPC/DPPC 1:1 (mol/mol) mixture we observed a strong influence of one phase on the other. In all cases the domains span the inner and outer leaflets of the membrane, suggesting a strong coupling between the inner and outer monolayers of the lipid membrane. This observation is also novel for unsupported lipid bilayers.
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Affiliation(s)
- L A Bagatolli
- Laboratory for Fluorescence Dynamics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 USA.
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16
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Inoue T, Nibu Y. Phase behavior of hydrated lipid bilayer composed of binary mixture of phospholipids with different head groups. Chem Phys Lipids 1999. [DOI: 10.1016/s0009-3084(99)00061-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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17
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Garidel P, Blume A. Miscibility of phospholipids with identical headgroups and acyl chain lengths differing by two methylene units: effects of headgroup structure and headgroup charge. BIOCHIMICA ET BIOPHYSICA ACTA 1998; 1371:83-95. [PMID: 9565658 DOI: 10.1016/s0005-2736(98)00005-4] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
We have investigated the influence of the chemical structure and charge of the hydrophillic headgroup on the miscibility of saturated phospholipids with acyl chain lengths differing by two methylene units, namely DMPA/DPPA, DMPC/DPPC, DMPE/DPPE and DMPG/DPPG (0.1 M NaCl). All four mixtures were analysed by DSC at pH 7. To study the influence of a change in headgroup charge, we additionally investigated DMPA/DPPA mixtures at pH 4 and 12, and DMPG/DPPG mixtures at pH 2. The experimental DSC thermograms were fitted using methods described before [Johann et al., Biophys. J. 71 (1996), 3215-3228] to obtain the temperatures of onset and end of melting and first approximations for the non-ideality parameters as a function of composition. The resulting phase diagrams were then fitted using a four non-ideality parameter model for non-ideal, non-symmetric mixing in both phases. The phase diagram of the system DMPG/DPPG has a lens-like shape, the non-ideality parameters rhog and rhol for the gel and the liquid-crystalline phase, respectively, are zero, indicating ideal mixing in both phases. For the other mixtures, differences in miscibility are observed depending on the structure of the headgroup. At pH 7, rhog > rhol, i.e., the miscibility in the liquid-crystalline phase is more ideal than in the gel state. All rhog values are positive and the sequence for rhog observed is PA>PE>PC>PG. Partial protonation of PA at pH 4 or complete deprotonation at pH 12 leads to negative non-ideality parameters for both phases, indicating a preference for mixed pair formation. Protonation of PG in DMPG/DPPG mixtures at pH 2 leads to positive non-ideality parameters for both phases, indicating a tendency for demixing. The results show, that the miscibility of phospholipids with identical headgroups but chain lengths differing by two methylene groups is dependent on headgroup structure and on headgroup charge.
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Affiliation(s)
- P Garidel
- Fachbereich Chemie, Universität Kaiserslautern, D-67653 Kaiserslautern, Germany
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Polozov IV, Polozova AI, Molotkovsky JG, Epand RM. Amphipathic peptide affects the lateral domain organization of lipid bilayers. BIOCHIMICA ET BIOPHYSICA ACTA 1997; 1328:125-39. [PMID: 9315610 DOI: 10.1016/s0005-2736(97)00080-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Using lipid-specific fluorescent probes, we studied the effects of amphipathic helical, membrane active peptides of the A- and L-type on membrane domain organization. In zwitterionic binary systems composed of mixtures of phosphatidylcholine and phosphatidylethanolamine, both types of peptides associated with the fluid phase. While binding with high affinity to fluid membranes, peptides were unable to penetrate into the lipid membrane in the gel state. If trapped kinetically by cooling from the fluid phase, peptides dissociated from the gel membrane on the time scale of several hours. While the geometrical shape of the alpha-helical peptides determines their interactions with membranes with non-bilayer phase propensity, the shape complementarity mechanism by itself is unable to induce lateral phase separation in a fluid membrane. Charge-charge interactions are capable of inducing lateral domain formation in fluid membranes. Both peptides had affinity for anionic lipids which resulted in about 30% enrichment of acidic lipids within several nanometers of the peptide's tryptophan, but there was no long-range order in peptide-induced lipid demixing. Peptide insertion in fluid acidic membranes was accompanied by only a small increase in bilayer surface and a decrease in polarity in the membrane core. Peptide-lipid charge-charge interactions were also capable of modulating existing domain composition in the course of the main phase transition in mixtures of anionic phosphatidylglycerol with zwitterionic phosphatidylcholine.
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Affiliation(s)
- I V Polozov
- Department of Biochemistry, McMaster University, Hamilton, Ont., Canada
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Garidel P, Johann C, Blume A. Nonideal mixing and phase separation in phosphatidylcholine-phosphatidic acid mixtures as a function of acyl chain length and pH. Biophys J 1997; 72:2196-210. [PMID: 9129822 PMCID: PMC1184414 DOI: 10.1016/s0006-3495(97)78863-5] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The miscibilities of phosphatidic acids (PAs) and phosphatidylcholines (PCs) with different chain lengths (n = 14, 16) at pH 4, pH 7, and pH 12 were examined by differential scanning calorimetry. Simulation of heat capacity curves was performed using a new approach that incorporates changes of cooperativity of the transition in addition to nonideal mixing in the gel and the liquid-crystalline phase as a function of composition. From the simulations of the heat capacity curves, first estimates for the nonideality parameters for nonideal mixing as a function of composition were obtained, and phase diagrams were constructed using temperatures for onset and end of melting, which were corrected for the broadening effect caused by a decrease in cooperativity. In all cases the composition dependence of the nonideality parameters indicated nonsymmetrical mixing behavior. The phase diagrams were therefore further refined by simulations of the coexistence curves using a four-parameter approximation to account for nonideal and nonsymmetrical mixing in the gel and the liquid-crystalline phase. The mixing behavior was studied at three different pH values to investigate how changes in headgroup charge of the PA influences the miscibility. The experiments showed that at pH 7, where the PA component is negatively charged, the nonideality parameters are in most cases negative, indicating that electrostatic effects favor a mixing of the two components. Partial protonation of the PA component at pH 4 leads to strong changes in miscibility; the nonideality parameters for the liquid-crystalline phase are now in most cases positive, indicating clustering of like molecules. The phase diagram for 1,2-dimyristoyl-sn-glycero-3-phosphatidic acid:1,2-dipalmitoyl-sn-glycero-3-phosphorylcholine mixtures at pH 4 indicates that a fluid-fluid immiscibility is likely. The results show that a decrease in ionization of PAs can induce large changes in mixing behavior. This occurs because of a reduction in electrostatic repulsion between PA headgroups and a concomitant increase in attractive hydrogen bonding interactions.
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Miscibility of binary phospholipid mixtures under hydrated and non-hydrated conditions. IV. Phosphatidylglycerols with different acyl chain length. Chem Phys Lipids 1995. [DOI: 10.1016/0009-3084(95)02442-l] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Inoue T, Nibu Y. Miscibility of binary phospholipid mixtures under hydrated and non-hydrated conditions. III. Reinvestigation of phosphatidic acids with different acyl chain length. Chem Phys Lipids 1995. [DOI: 10.1016/0009-3084(95)02441-k] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Nibu Y, Inoue T. Miscibility, of binary phospholipid mixtures under hydrated and non-hydrated conditions. II. Phosphatidylethanolamines with different acyl chain length. Chem Phys Lipids 1995. [DOI: 10.1016/0009-3084(95)02440-t] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Abstract
The physical concepts underlying the lateral distribution of the components forming a lamellar assembly of amphiphiles are discussed in this review. The role of amphiphiles' molecular structure and/or aqueous environment (ionic strength, water soluble substances) on formation and stability of lateral patterns is investigated. A considerable effort is devoted to the analysis of the properties of patterned structure which can be different from those of randomly mixed multi-component lamellae. Examples include adhesion and fusion among laterally inhomogeneous bilayers, enhanced interfacial adsorption of ions and polymers, enhanced transport across the bilayer, modified mechanical properties, local stabilization of non-planar geometries (pores, edges) and related phenomena (electroporation, budding transition and so on). Furthermore, an analysis of chemical reactivity within or at the water interface of a laterally inhomogeneous bilayer is briefly discussed. A link between these concepts and experimental findings taken from the biological literature is attempted throughout the review.
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Affiliation(s)
- A Raudino
- Dipartimento di Scienze Chimiche, Università di Catania, Italy
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24
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Polozov IV, Molotkovsky JG, Bergelson LD. Anthrylvinyl-labeled phospholipids as membrane probes: the phosphatidylcholine-phosphatidylethanolamine system. Chem Phys Lipids 1994; 69:209-18. [PMID: 8194157 DOI: 10.1016/0009-3084(94)90002-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The phase behavior of mixtures of phosphatidylcholine (PC) with phosphatidylethanolamine (PE) identical or differing in their fatty acid composition has been investigated by using the steady-state fluorescence anisotropy of anthrylvinyl-labeled PC and PE (APC and APE) as well as of the non-lipid probe 1,6-diphenyl-1,3,5-hexatriene (DPH) to detect temperature-dependent changes in multilayer liposomes. APC, but not APE, was able to detect the pretransition of dimyristoyl-PC. The phospholipid probes APC and APE showed the main phase transition of their unlabeled disaturated analogues at temperatures almost identical with those revealed by differential scanning calorimetry, whereas the onset of the PE phase transition recorded by DPH was several degrees higher. In PC-PE mixtures with high content of PE the phase transitions shown by APC and APE were broader than those recorded by DPH. Comparison of phase diagrams constructed on the basis of fluorescence anisotropy and calorimetric data led to the conclusion that in biphasic PE and PC-PE systems DPH tends to partition into solid regions, whereas the anthrylvinyl-labeled phospholipids distribute more evenly between coexisting phases or prefer fluid domains. The use of anthrylvinyl phospholipid probes made it possible to demonstrate that PEs and PCs identical in their fatty acids are not miscible completely, not only below but also well above Tm of the higher melting component. Generally, APC and APE fluorescence anisotropy measurements correctly reflect headgroup-dependent phase segregations in mixtures of PC with PE, but may lead to ambiguous conclusions if demixing is caused by differences in the hydrocarbon chains.
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Affiliation(s)
- I V Polozov
- M.M. Shemyakin Institute of Bio-organic Chemistry, Russian Academy of Sciences, Moscow
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25
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Marassi FM, Djukic S, Macdonald PM. Influence of lipid lateral distribution on the surface charge response of the phosphatidylcholine headgroup as detected using 2H nuclear magnetic resonance. BIOCHIMICA ET BIOPHYSICA ACTA 1993; 1146:219-28. [PMID: 8452858 DOI: 10.1016/0005-2736(93)90359-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The effect of lipid lateral distribution on the surface charge response of the phosphatidylcholine headgroup, in bilayers composed of binary mixtures of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and 1,2-dimyristoyl-sn-glycero-3-phosphate (DMPA), was investigated by monitoring the deuterium nuclear magnetic resonance (2H-NMR) spectrum of choline-deuterated phosphatidylcholine as a function of temperature and DMPA concentration. Addition of DMPA at temperatures corresponding to fully liquid-crystalline membranes caused a progressive increase (decrease) in the 2H-NMR quadrupole splitting from POPC-alpha-d2 (POPC-beta-d2), in agreement with the known response of phosphatidylcholine to negative membrane surface charge (Seelig, J., Macdonald, P.M. and Scherer, P.G. (1987) Biochemistry 26, 7535-7541). Lateral phase separation of DMPA-rich domains was induced in these mixtures by lowering the temperature in the range from 60 degrees C to -15 degrees C, and was accompanied by a reversal of the original effects of DMPA on the quadrupole splitting. Analysis of the 2H-NMR spectral response allows one to generate a temperature/composition phase diagram for the POPC/DMPA system. We conclude that 2H-NMR of headgroup-deuterated phosphatidylcholine can be employed to sense and to quantify inhomogeneities in the lateral distribution of charged membrane components.
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Affiliation(s)
- F M Marassi
- Department of Chemistry, University of Toronto, Ontario, Canada
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26
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Inoue T, Tasaka T, Shimozawa R. Miscibility of binary phospholipid mixtures under hydrated and unhydrated conditions. I. Phosphatidic acids with different acyl chain length. Chem Phys Lipids 1992. [DOI: 10.1016/0009-3084(92)90036-o] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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27
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Bradshaw JP, Edenborough MS, Sizer PJ, Watts A. A description of the phospholipid arrangement intermediate to the humidity produced Lα and HII phases in dioleoylphosphatidylcholine and its modification by dioleoylphosphatidylethanolamine as studied by X-ray diffraction. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 1989. [DOI: 10.1016/0005-2736(89)90460-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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28
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Quinn PJ. Principles of membrane stability and phase behavior under extreme conditions. J Bioenerg Biomembr 1989; 21:3-19. [PMID: 2651426 DOI: 10.1007/bf00762209] [Citation(s) in RCA: 64] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Biological membranes consist of a complex assortment of lipids and proteins. The arrangement of the components, particularly in regard to their lateral disposition in the plane of the membrane under physiological conditions, is dependent on the phase behavior of the different membrane lipids and the way that this behavior is modified by interaction with other membrane components and electrolytes in the aqueous medium. Irreversible phase separation of components within the membrane may result from exposure to extreme environmental conditions including temperature, pressure, or electrolyte concentration. The principles underlying the phase-mixing behavior of model membrane systems can be used to provide useful information about the factors that determine the stability of biomembranes under physiological and non-physiological conditions. These data are reviewed and used to predict events that take place when membranes are exposed to environmental stress.
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Affiliation(s)
- P J Quinn
- Department of Biochemistry, King's College London, United Kingdom
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29
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Ipsen JH, Mouritsen OG. Modelling the phase equilibria in two-component membranes of phospholipids with different acyl-chain lengths. BIOCHIMICA ET BIOPHYSICA ACTA 1988; 944:121-34. [PMID: 3179284 DOI: 10.1016/0005-2736(88)90425-7] [Citation(s) in RCA: 79] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
A phenomenological model is proposed to describe the membrane phase equilibria in binary mixtures of saturated phospholipids with different acyl-chain lengths. The model is formulated in terms of thermodynamic and thermomechanic properties of the pure lipid bilayers, specifically the chain-melting transition temperature and enthalpy, the hydrophobic bilayer thickness, and the lateral area compressibility modulus. The model is studied using a regular solution theory made up of a set of interaction parameters which directly identify that part of the lipid-lipid interaction which is due to hydrophobic mismatch of saturated chains of different lengths. It is then found that there is effectively a single universal interaction parameter which, in the full composition range, describes the phase equilibria in mixtures of DMPC/DPPC, DPPC/DSPC, DMPC/DSPC, and DLPC/DSPC, in excellent agreement with experimental measurements. The model is used to predict the variation with temperature and composition of the specific heat, as well as of the average membrane thickness and area in each of the phases. Given the value of the universal interaction parameter, the model is then used to predict the phase diagrams of binary mixtures of phospholipids with different polar head groups, e.g., DPPC/DPPE, DMPC/DPPE and DMPE/DSPC. By comparison with experimental results for these mixtures, it is shown that difference in acyl-chain lengths gives the major contribution to deviation from ideal mixing. Application of the model to mixtures with non-saturated lipids is also discussed.
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Affiliation(s)
- J H Ipsen
- Department of Structural Properties of Materials, Technical University, Lyngby, Denmark
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30
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Cunningham B, Tamura-Lis W, Lis L, Quinn P. Time-resolved X-ray diffraction measurements of phosphatidylcholine-phosphatidylethanolamine mixtures: Effect of phosphatidylethanolamine acyl chain length. J Colloid Interface Sci 1988. [DOI: 10.1016/0021-9797(88)90422-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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31
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Boyanov AI, Koynova RD, Tenchov BG. Effect of lipid admixtures on the L-dipalmitoylphosphatidylcholine subtransition. Chem Phys Lipids 1986; 39:155-63. [PMID: 3753903 DOI: 10.1016/0009-3084(86)90109-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The effect of lipid admixtures on the properties of the L-dipalmitoylphosphatidylcholine (L-DPPC) subtransition is investigated by using high-sensitivity differential scanning calorimetry. The four admixtures used are D-DPPC, L-dipalmitoylphosphatidylethanolamine (L-DPPE), cholesterol, and palmitic acid. In all cases the subtransition decreases in enthalpy until disappearance with increase of the admixture concentrations. About 5-7 mol% of D-DPPC or palmitic acid are sufficient for abolishment (without position shifts) of the subtransition, while, on addition of L-DPPE or cholesterol, it persists up to about 20 mol% of the admixture and its disappearance is accompanied by a slight shift to higher temperatures. These data are tentatively interpreted in terms of lateral mixing of L-DPPC and admixture as indicating compound formation with D-DPPC and palmitic acid, and clustering of L-DPPE and cholesterol.
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33
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Smith GJ. THE EFFECTS OF AGGREGATION ON THE FLUORESCENCE and THE TRIPLET STATE YIELD OF HEMATOPORPHYRIN. Photochem Photobiol 1985. [DOI: 10.1111/j.1751-1097.1985.tb03459.x] [Citation(s) in RCA: 72] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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34
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Stelzer KJ, Gordon MA. Interactions of pyrethroids with phosphatidylcholine liposomal membranes. BIOCHIMICA ET BIOPHYSICA ACTA 1985; 812:361-8. [PMID: 3967018 DOI: 10.1016/0005-2736(85)90310-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Interactions of several pyrethroids with membrane lipids in the form of dipalmitoylphosphatidylcholine (DPPC) liposomes have been studied using fluorescent membrane probes. Fluorescence anisotropy values and lifetimes (determined by phase-shift and demodulation techniques) of the fluorescent probe, 1,6-diphenyl-1,3,5-hexatriene, were decreased in gel phase liposomes by pyrethroids at concentrations on the order of 10 microM. The pyrethroids containing a cyano substituent were also observed to cause collisional quenching of diphenylhexatriene fluorescence. Pyrethroids differed in their effectiveness at lowering the phase transition temperature of DPPC, and in their ability to broaden the temperature range of this transition. The fluorescence intensity of DPPC-incorporated chlorophyll a was used to monitor the pretransition of DPPC and the lateral diffusion of a membrane component located in the polar headgroup region. Permethrin did not affect chlorophyll a fluorescence intensity at any temperature. It may be concluded from these results that pyrethroids are preferentially located in the interior hydrophobic regions of the lipid bilayer, and that these compounds can disorder hydrocarbon packing in the bilayer core. However, polar headgroups were not disordered, and diffusion of membrane components in the polar headgroup region was not altered.
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35
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Kapitza HG, Rüppel DA, Galla HJ, Sackmann E. Lateral diffusion of lipids and glycophorin in solid phosphatidylcholine bilayers. The role of structural defects. Biophys J 1984; 45:577-87. [PMID: 6713070 PMCID: PMC1434885 DOI: 10.1016/s0006-3495(84)84195-8] [Citation(s) in RCA: 64] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The lateral mobility of the lipid analog N-4-nitrobenzo-2-oxa-1,3 diazole phosphatidylethanolamine and of the integral protein glycophorin in giant dimyristoylphosphatidylcholine vesicles was studied by the photobleaching technique. Above the temperature of the chain-melting transition (Tm = 23 degrees C), the diffusion coefficient, Dp, of the protein [Dp = (4 +/- 2) X 10(-8) cm2/s at 30 degrees C] was within the experimental errors equal to the corresponding values DL of the lipid analog. In the P beta 1 phase the diffusion of lipid and glycophorin was studied as a function of the probe and the protein concentration. (a) At low lipid-probe content (cL less than 5 mmol/mol of total lipid), approximately 20% of the probe diffuses fast (D approximately equal to 10(-8) - 10(-9) cm2/s), while the mobility of the rest is strongly reduced (D less than 10(-10) cm2/s). At a higher concentration (cp approximately 20 mmol), all probe is immobilized (D less than 10(-10) cm2/s). (b) Incorporation of glycophorin up to cp = 0.4 mmol/mol of total lipid leads to a gradual increase of the fraction of mobile lipid probe due to the lateral-phase separation into a pure P beta 1 phase and a fraction of lipid that is fluidized by strong hydrophilic lipid-protein interaction. (c) The diffusion of the glycophorin molecules is characterized by a slow and a fast fraction. The latter increases with increasing protein content, which is again due to the lateral-phase separation caused by the hydrophilic lipid-protein interaction. The results are interpreted in terms of a fast transport along linear defects in the P beta 1 phase, which form quasi-fluid paths for a nearly one dimensional and thus very effective transport. Evidence for this interpretation of the diffusion measurements is provided by freeze-fracture electron microscopy.
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36
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Sugár IP, Monticelli G. Landau theory of two-component phospholipid bilayers. I. Phosphatidylcholine/phosphatidylethanolamine mixtures. Biophys Chem 1983; 18:281-9. [PMID: 6661496 DOI: 10.1016/0301-4622(83)80041-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Priest's phenomenological model (Mol. Cryst. Liq. Cryst. 60 (1980) 167.) on one- and two-component PC bilayers is extended here. We constructed a new excess free energy term in the state function to describe the thermodynamic properties of the two-component phospholipid bilayers where the chain lengths and the polar heads of the components can be different simultaneously. By means of this generalized state function, we can calculate the phase diagrams of DPPC/DPPE, DMPC/DMPE, DMPC/DPPE, DPPC/DMPE and DSPC/DMPE mixtures. We obtained complete miscibility both in the liquid crystalline and in the gel phase if the chain lengths of the components were the same. If the chain length of the PE component was longer than that of the PC component, we obtained a peritectic system. A eutectic system was obtained in the reverse case. The results of the model were compared with the experimental data available. Applying the quasichemical approximation, we determined the molecular meaning of the phenomenological model parameters. Namely, sigma and gamma are proportional to the sublimation heat of the CH2 group in the long-chain alkanes and to the hydrogen-bonding energy between the polar heads of the ethanolamines; otherwise the model resulted in--1.94 kcal/mol per CH2 for the sublimation heat and --1.4 kcal/mol for the hydrogen-bond energy.
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37
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Gordon LM, Mobley PW, Esgate JA, Hofmann G, Whetton AD, Houslay MD. Thermotropic lipid phase separations in human platelet and rat liver plasma membranes. J Membr Biol 1983; 76:139-49. [PMID: 6315947 DOI: 10.1007/bf02000614] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Electron spin resonance (ESR) studies were conducted on human platelet plasma membranes using 5-nitroxide stearate, I(12,3). The polarity-corrected order parameter S and polarity-uncorrected order parameters S(T parallel) and S(T perpendicular) were independent of probe concentration at low I(12.3)/membrane protein ratios. At higher ratios, S and S(T perpendicular) decreased with increasing probe concentration while S(T parallel) remained unchanged. This is the result of enhanced radical interactions due to probe clustering. A lipid phase separation occurs in platelet membranes that segregates I(12,3) for temperatures less than 37 degrees C. As Arrhenius plots of platelet acid phosphatase activity exhibit a break at 35 to 36 degrees C, this enzyme activity may be influenced by the above phase separation. Similar experiments were performed on native [cholesterol/phospholipid ratio (C/P) = 0.71] and cholesterol-enriched [C/P = 0.85] rat liver plasma membranes. At 36 degrees C, cholesterol loading reduces I(12,3) flexibility and decreases the probe ratio at which radical interactions are apparent. The latter effects are attributed to the formation of cholesterol-rich lipid domains, and to the inability of I(12,3) to partition into these domains because of steric hinderance. Cholesterol enrichment increases both the high temperature onset of the phase separation occurring in liver membranes from 28 degrees to 37 degrees C and the percentage of probe-excluding, cholesterol-rich lipid domains at elevated temperatures. A model is discussed attributing the lipid phase separation in native liver plasma membranes to cholesterol-rich and -poor domains. As I(12,3) behaves similarly in cholesterol-enriched liver and human platelet plasma membranes, cholesterol-rich and -poor domains probably exist in both systems at physiologic temperatures.
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Presti FT, Pace RJ, Chan SI. Cholesterol-phospholipid interaction in membranes. 2. Stoichiometry and molecular packing of cholesterol-rich domains. Biochemistry 1982; 21:3831-5. [PMID: 7138808 DOI: 10.1021/bi00259a017] [Citation(s) in RCA: 147] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
A model for the molecular interaction between cholesterol and phospholipid in bilayer membranes is presented. We propose that cholesterol forms associations with phospholipids with stoichiometries of both 1:1 and 1:2. A hydrogen bond between the beta-OH of cholesterol and the glycerol ester oxygen of a phospholipid is suggested as a likely mechanism for tight binding in a 1:1 complex. A second phospholipid molecule is loosely associated with the complex to form domains of 1:2 stoichiometry, which may coexist with pure phospholipid domains. Interfacial boundary phospholipid separates these two domains. Under conditions in which interfacial phospholipid is maximal, the perturbed phospholipid assumes a composition of 20 mol % cholesterol. To account for the phase behavior and surface properties of cholesterol-lipid membranes, we propose a molecular packing model for linear arrays within the cholesterol-rich domains. In this arrangement, two rows of 1:1 complex run antiparallel with loosely associated phospholipid intercalated between them. The loosely associated phospholipid can pack in the nearly hexagonal manner in which pure crystalline phospholipid is known to pack. The model provides maximal van der Waals contact in the hydrocarbon region of the bilayer and can maintain phospholipids as cholesterol's nearest neighbors at all concentrations up to 50 mol % cholesterol. The model is compatible with the diverse experimental observations compiled by many investigators over the past decade.
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40
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Wittebort RJ, Blume A, Huang TH, Das Gupta SK, Griffin RG. Carbon-13 nuclear magnetic resonance investigations of phase transitions and phase equilibria in pure and mixed phospholipid bilayers. Biochemistry 1982; 21:3487-502. [PMID: 7115682 DOI: 10.1021/bi00257a036] [Citation(s) in RCA: 75] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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41
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McElhaney RN. The use of differential scanning calorimetry and differential thermal analysis in studies of model and biological membranes. Chem Phys Lipids 1982; 30:229-59. [PMID: 7046969 DOI: 10.1016/0009-3084(82)90053-6] [Citation(s) in RCA: 261] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Differential scanning calorimetry (DSC), and to a lesser extent differential thermal analysis (DTA), are powerful yet relatively rapid and inexpensive thermodynamic techniques for studying the thermotropic phase behavior of lipids in model and biological membranes, without the introduction of exogenous probe molecules. In this review the principles as well as the scope and limitations of DSC and DTA are discussed first. The application of these techniques to the study of the thermotropic phase behavior of aqueous dispersions of various single synthetic phospholipids are then summarized, and the effects of cholesterol, free fatty acids, lysophospholipids, drugs, anesthetics and proteins on the gel to liquid-crystalline phase transitions exhibited by these model systems are discussed. The phase mixing properties of model membranes consisting of mixtures of two or more synthetic or natural phospholipids are considered next. Finally, the thermotropic phase behavior of prokaryotic plasma membranes and of the plasma, microsomal and mitochondrial membranes of eukaryotic cells are reviewed, and the applications of DSC and DTA to study the thermal behavior of specific membrane proteins, as well as the physical properties of the membrane lipid phase, are summarized.
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Arnold K, Lösche A, Gawrisch K. 31p-NMR investigations of phase separation in phosphatidylcholine/phosphatidylethanolamine mixtures. BIOCHIMICA ET BIOPHYSICA ACTA 1981; 645:143-8. [PMID: 7260080 DOI: 10.1016/0005-2736(81)90522-8] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
A phase diagram of DPPC-DPPE mixture is constructed by an analysis of the temperature dependence of the anisotropy of chemical shift of the 31P-NMR signals of the individual components. At each temperature the phase state of the individual phospholipids is described. Thus 31P-NMR is more informative than other methods such as ESR, DSC and fluorescence. The measurements confirm the conclusion of other authors that there is a phase separation in the gel state. In the temperature range of the phase transition the molecules are exchanged rapidly between liquid-crystalline and solid regions. In addition to the phase diagram a theoretical approach is applied to estimate the relative distribution of like and unlike molecules in the liquid-crystalline state and a nonrandom distribution is found.
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Leonards KS, Haug A. Potassium- and calcium-induced alterations in lipid interactions of isolated plasma membranes from blastocladiella emersonii. Evidence for an adenosine 5'-triphosphate requirement. Biochemistry 1981; 20:1784-9. [PMID: 6261805 DOI: 10.1021/bi00510a012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The physical-chemical properties of the isolated plasma membranes from zoospores of the chytridiomycete Blastocladiella emersonii were investigated, with electron spin resonance (ESR) spectroscopy, using the spin-label 5-nitroxystearate (5-NS). Both isolated plasma membranes and aqueous dispersion of the lipids extracted from the plasma membranes were spin-labeled and analyzed. Plots of the hyperfine splitting parameter (2T) vs. temperature indicated that the middle break point, TM, initially observed in experiments with spin-labeled zoospores in vivo [Leonards, K. S., & Haug, A. (1980) Biochim. Biophys. Acta 600, 805-816], was the result of a lipid-lipid interaction (glycolipid-glycolipid or glycolipid-neutral lipid) rather than a lipid-protein interaction. This interaction was markedly affected by Ca2+ ions, which interacted directly with the lipid components, increasing TM from 11 +/- 1 (Ca2+ removed by EDTA) to 21 +/- 1 degree C (10 mM Ca2+) in the lipid dispersions and from 12 +/- 1 to 23 +/- 1 degree C in the plasma membrane preparations. The initial ESR studies on spin-labeled zoospores in vivo had also demonstrated that the addition of K+ ions could reverse the Ca2+ ion effect, downshifting TM from 22 +/- 1 to 10 +/- 1 degree C. The addition of of K+ ions to the isolated plasma membrane had no affect on TM, indicating that K+ ions do not simply replace Ca2+ ions but exert their effect indirectly on the membrane. However, after the inclusion of ATP, K+ ions could reverse the Ca2+ ion effect. it was determined that the ATp generated an "energized membrane" state which permitted the K+ ions to reverse the Ca2+ effect. Since K+ ions have been shown to depolarize the membrane potential in both zoospores and isolated zoospore plasma membrane preparations (generated by ATP), were suggest that the K+ ion induced reversal of the Ca2+ ion effect, and therefore the change in the lipid-lipid interactions responsible for TM, is a consequence of the K+ ion induced depolarization of the membrane potential.
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Phase Transitions in Two-Dimensional Amphiphilic Systems. ACTA ACUST UNITED AC 1981. [DOI: 10.1016/b978-0-12-571814-1.50010-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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45
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Strauss G, Ingenito EP. Stabilization of liposome bilayers to freezing and thawing: effects of cryoprotective agents and membrane proteins. Cryobiology 1980; 17:508-15. [PMID: 7438768 DOI: 10.1016/0011-2240(80)90062-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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46
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Cheng WH. A theoretical description of phase diagrams for nonideal lipid mixtures. BIOCHIMICA ET BIOPHYSICA ACTA 1980; 600:358-66. [PMID: 7407119 DOI: 10.1016/0005-2736(80)90439-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
A theoretical description of phase diagrams for nonideal lipid mixtures is presented. The phase diagrams in this model are constructed by a quasi-chemical approach for the calculations of enthalpies of the regular solutions and by van der Waals attractive energy of lipids which described the degree of nonideality in the solid and fluid phases. The results of theoretical calculations of phase diagrams for dimyristoyl phsophatidylcholine/dipalmitoyl phosphatidylcholine dimyristoyl phosphatidylcholine/distearoyl phosphatidylcholine, and dipalmitoyl phosphatidylcholine/distearoyl phosphatidylcholine mixtures are in good agreement with experimental data.
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Hurley JK, Castelli F, Tollin G. CHLOROPHYLL PHOTOCHEMISTRY IN CONDENSED MEDIA—II. TRIPLET STATE QUENCHING AND ELECTRON TRANSFER TO QUINONE IN LIPOSOMES. Photochem Photobiol 1980. [DOI: 10.1111/j.1751-1097.1980.tb03989.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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48
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Abstract
We have studied platelet adhesion to phospholipid model membranes in vitro. Our results showed that films made of egg lecithin, dioleoyllecithin or phosphatidylethanolamine from two different sources (egg yolk and E. coli) are unadhesive for platelets. Platelets adhered to films made of distearoyllecithin, dipalmitoyllecithin and N--stearoylsphingomyelin. According to electron spin resonance measurements, the former lipids were present during incubation with platelet-rich plasma above the phase transition temperature, whereas the latter were present below this temperature. Cross-linking of phosphatidylethanolamine films with glutaraldehyde or egg lecithin, as well as dioleoyllecithin with OsO4, abolishes the phase transition of the lipids in these films, transforming them to the solid state. After such treatment the films become adhesive for platelets. Thus fluid liquid crystalline phospholipid membranes are unadhesive for platelets; solid crystalline (gel) films are adhesive for these cells. We suggest that the fluidity of the plasma membrane has an essential role in making the endothelium unadhesive for platelets in vivo.
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49
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Partition of a fluorescent molecule between liquid-crystalline and crystalline regions of membranes. J Membr Biol 1979. [DOI: 10.1007/bf01869298] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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50
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Dijkmans H, Leblanc RM, Cogniaux F, Aghion J. PROPERTIES OF CHLOROPH'YLL-LECITHIN VESICLES: ULTRACENTRIFUGATION, ABSORBANCE, EMISSION AND PHOTOBLEACHING. Photochem Photobiol 1979. [DOI: 10.1111/j.1751-1097.1979.tb07060.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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