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Humphrey M, Abdelmesseh Nekhala I, Scheinpflug K, Krylova O, Schäfer AB, Buttress JA, Wenzel M, Strahl H. Tracking Global and Local Changes in Membrane Fluidity Through Fluorescence Spectroscopy and Microscopy. Methods Mol Biol 2023; 2601:203-229. [PMID: 36445586 DOI: 10.1007/978-1-0716-2855-3_11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Membrane fluidity is a critical parameter of cellular membranes, which cells continuously strive to maintain within a viable range. Interference with the correct membrane fluidity state can strongly inhibit cell function. Triggered changes in membrane fluidity and associated impacts on lipid domains have been postulated to contribute to the mechanism of action of membrane targeting antimicrobials, but the corresponding analyses have been hampered by the absence of readily available analytical tools. Here, we expand upon the protocols outlined in the first edition of this book, providing further and alternative protocols that can be used to measure changes in membrane fluidity. We provide detailed protocols, which allow straightforward in vivo and in vitro measurement of antibiotic compound-triggered changes in membrane fluidity and fluid membrane microdomains. Furthermore, we summarize useful strains constructed by us and others to characterize and confirm lipid specificity of membrane antimicrobials directly in vivo.
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Affiliation(s)
- Madeleine Humphrey
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle upon Tyne, UK
| | - Ireny Abdelmesseh Nekhala
- Division of Chemical Biology, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Kathi Scheinpflug
- Department of Chemical Biology, Leibniz-Institut für Molekulare Pharmakologie (FMP), Berlin, Germany
| | - Oxana Krylova
- Department of Chemical Biology, Leibniz-Institut für Molekulare Pharmakologie (FMP), Berlin, Germany
| | - Ann-Britt Schäfer
- Division of Chemical Biology, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Jessica A Buttress
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle upon Tyne, UK
| | - Michaela Wenzel
- Division of Chemical Biology, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden.
| | - Henrik Strahl
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle upon Tyne, UK.
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Koitabashi K, Nagumo H, Nakao M, Machida T, Yoshida K, Sakai-Kato K. Acidic pH-induced changes in lipid nanoparticle membrane packing. Biochim Biophys Acta Biomembr 2021; 1863:183627. [PMID: 33901441 DOI: 10.1016/j.bbamem.2021.183627] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 04/07/2021] [Accepted: 04/16/2021] [Indexed: 12/12/2022]
Abstract
To enable the release of the encapsulated nucleic acids into the cytosol of targeted cells, the interaction of lipid nanoparticles (LNPs) with endosomes is critical. We investigated changes in the physicochemical properties of LNPs containing ionizable cationic lipids that were induced by acidic pH, which reflects the conditions in the maturation of endosomes. We prepared a LNP containing an ionizable cationic lipid. The laurdan generalized polarization values, which are related to the hydration degree of the lipid membrane interface and are often used as an indicator of membrane packing, decreased with a decrease in pH value, showing that the membrane packing was decreased under acidic conditions. Furthermore, the pH-induced variation increased with an increasing percentage of ionizable cationic lipids in the LNPs. These results indicated that electrostatic repulsion between lipid molecules at acidic pH decreased the packing density of the lipids in the LNP membrane. Reducing the order of lipids could be a trigger to form a non-bilayer structure and allow fusion of the LNPs with the membrane of maturing endosomes in an acidic environment. The LNPs were used to incorporate and transport small interfering RNA (siRNA) into cells for knockdown of the expression of β-galactosidase. The knockdown efficiency of siRNA encapsulated in LNPs tended to increase with the ratio of KC2. These results, which demonstrate the underlying phenomena for the fusion of membranes, will help clarify the mechanism of the release of encapsulated nucleic acids.
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Affiliation(s)
- Kyoka Koitabashi
- School of Pharmacy, Kitasato University, Shirokane 5-9-1, Minato-ku, Tokyo 108-8641, Japan
| | - Hiroki Nagumo
- School of Pharmacy, Kitasato University, Shirokane 5-9-1, Minato-ku, Tokyo 108-8641, Japan
| | - Mizuka Nakao
- School of Pharmacy, Kitasato University, Shirokane 5-9-1, Minato-ku, Tokyo 108-8641, Japan
| | - Tomoko Machida
- School of Pharmacy, Kitasato University, Shirokane 5-9-1, Minato-ku, Tokyo 108-8641, Japan
| | - Kohki Yoshida
- School of Pharmacy, Kitasato University, Shirokane 5-9-1, Minato-ku, Tokyo 108-8641, Japan
| | - Kumiko Sakai-Kato
- School of Pharmacy, Kitasato University, Shirokane 5-9-1, Minato-ku, Tokyo 108-8641, Japan.
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Abstract
Bioactive omega-3 polyunsaturated fatty acids have been shown to reduce the risk of death in patients with cardiovascular disease and alleviate the symptoms of other inflammatory diseases. However, the mechanisms of action of these effects remain unclear. It has been postulated that omega-3 polyunsaturated fatty acids modify cell membranes by incorporation into the membrane and altering the signaling properties of cellular receptors. In this chapter, we explore the effects of omega-3 polyunsaturated fatty acids on cell membrane structure and function. We present a review of the current evidence for the health benefits of these compounds and explore the molecular mechanisms through which omega-3 polyunsaturated fatty acids interact with membrane lipids and modulate bilayer structure. Using computational models of multicomponent phospholipid bilayers, we assess the consequences of incorporation of these fatty acids on membrane lipid packing, water permeation, and membrane structure.
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Affiliation(s)
- Manuela A A Ayee
- Department of Engineering, Dordt University, Sioux Center, IA, United States.
| | - Brendan C Bunker
- Department of Engineering, Dordt University, Sioux Center, IA, United States
| | - Jordan L De Groot
- Department of Engineering, Dordt University, Sioux Center, IA, United States
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Efimova SS, Khaleneva DA, Litasova EV, Piotrovskiy LB, Ostroumova OS. The mechanisms of action of water-soluble aminohexanoic and malonic adducts of fullerene C 60 with hexamethonium on model lipid membranes. Biochim Biophys Acta Biomembr 2020; 1862:183433. [PMID: 32763244 DOI: 10.1016/j.bbamem.2020.183433] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 07/10/2020] [Accepted: 07/22/2020] [Indexed: 10/23/2022]
Abstract
In an attempt to understand the possibility of applications of the fullerene-based systems for transporting various polar compounds like hexamethonium through the blood-brain barrier, we studied the influence of a series of derivatives of fullerene C60 in the form of salts with hexamethonium bis-anion, namely the adducts of fullerenols with 6-aminohexanoic acid (IEM-2197), and two bis-adduct malonic acid derivatives of fullerene with addents bound in two hemispheres (IEM-2143) and in equatorial positions (IEM-2144), on model membranes. We showed that IEM-2197 induced the disintegration of the bilayers composed of DOPC at the concentrations more than 2 mg/ml. IEM-2144 and IEM-2143-induced ion-permeable pores at concentrations of 0.3 and 0.02 mg/ml, respectively; herewith, IEM-2143 was characterized by the greater efficiency than IEM-2144. IEM-2197 did not significantly affect the phase behavior of DPPC, while the melting temperature significantly decreased with addition of IEM-2144 and IEM-2143. The increase in the half-width of the main transition peaks by more than 2.0 °C in the presence of IEM-2144 and IEM-2143 was observed, along with the pronounced peak deconvolution. We proposed that the immersion of IEM-2144 and IEM-2143 into the polar region of the DOPC or DPPC bilayers led to an increase in the relative mobility of tails and formation of ion-permeable defects. IEM-2197 demonstrated the more pronounced effects on the melting and ion permeability of PG- and PS-containing bilayers compared to PC-enriched membranes. These results indicated that IEM-2197 preferentially interacts with the negatively charged lipids compared to neutral species.
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Affiliation(s)
- S S Efimova
- Institute of Cytology, Russian of the Academy of Science, Saint Petersburg, Russia.
| | - D A Khaleneva
- Institute of Cytology, Russian of the Academy of Science, Saint Petersburg, Russia
| | - E V Litasova
- Institute of Experimental Medicine, Saint Petersburg, Russia
| | - L B Piotrovskiy
- Institute of Experimental Medicine, Saint Petersburg, Russia.
| | - O S Ostroumova
- Institute of Cytology, Russian of the Academy of Science, Saint Petersburg, Russia
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Hsu WY, Masuda T, Afonin S, Sakai T, Arafiles JVV, Kawano K, Hirose H, Imanishi M, Ulrich AS, Futaki S. Enhancing the activity of membrane remodeling epsin-peptide by trimerization. Bioorg Med Chem Lett 2020; 30:127190. [PMID: 32317210 DOI: 10.1016/j.bmcl.2020.127190] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 04/08/2020] [Accepted: 04/11/2020] [Indexed: 12/13/2022]
Abstract
Modulating the structural dynamics of biomembranes by inducing bilayer curvature and lipid packing defects has been highlighted as a practical tool to modify membrane-dependent cellular processes. Previously, we have reported on an amphipathic helical peptide derived from the N-terminal segment (residues 1-18, EpN18) of epsin-1, which can promote membrane remodeling including lipid packing defects in cell membranes. However, a high concentration is required to exhibit a pronounced effect. In this study, we demonstrate a significant increase in the membrane-remodeling effect of EpN18 by constructing a branched EpN18 homotrimer. Both monomer and trimer could enhance cell internalization of octaarginine (R8), a cell-penetrating peptide. The EpN18 trimer, however, promoted the uptake of R8 at an 80-fold lower concentration than the monomer. Analysis of the generalized polarization of a polarity-sensitive dye (di-4-ANEPPDHQ) revealed a higher efficacy of trimeric EpN18 in loosening the lipid packing in the cell membrane. Circular dichroism measurements in the presence of lipid vesicles showed that the EpN18 trimer has a higher α-helix content compared with the monomer. The stronger ability of the EpN18 trimer to impede negative bilayer curvature is also corroborated by solid-state 31P NMR spectroscopy. Hence, trimerizing peptides can be considered a promising approach for an exponential enhancement of their membrane-remodeling performance.
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Affiliation(s)
- Wei-Yuan Hsu
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Toshihiro Masuda
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Sergii Afonin
- Institute of Biological Interfaces (IBG-2), Karlsruhe Institute of Technology (KIT), P.O.B. 3640, 76021 Karlsruhe, Germany
| | - Takayuki Sakai
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | | | - Kenichi Kawano
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Hisaaki Hirose
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Miki Imanishi
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Anne S Ulrich
- Institute of Biological Interfaces (IBG-2), Karlsruhe Institute of Technology (KIT), P.O.B. 3640, 76021 Karlsruhe, Germany; Institute of Organic Chemistry (IOC), KIT, Fritz-Haber-Weg 6, 76131 Karlsruhe, Germany
| | - Shiroh Futaki
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan.
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Steele HBB, Sydor MJ, Anderson DS, Holian A, Ross JBA. Using Time-Resolved Fluorescence Anisotropy of di-4-ANEPPDHQ and F2N12S to Analyze Lipid Packing Dynamics in Model Systems. J Fluoresc 2019; 29:347-352. [PMID: 30937610 DOI: 10.1007/s10895-019-02363-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Accepted: 03/10/2019] [Indexed: 11/29/2022]
Abstract
The fluorescence probes di-4-ANEPPDHQ and F2N12S have solvochromatic emission spectra and fluorescence lifetimes that are sensitive to order within the environment of lipid membranes. We show in this communication that the time-resolved fluorescence anisotropy of these probes, analyzed either by the wobble-in-a-cone model or by the model-independent order parameter S2, provides complementary information about dynamics and lipid packing in a variety of homogeneous lipid membranes systems.
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Affiliation(s)
- Harmen B B Steele
- Department of Chemistry & Biochemistry, University of Montana, Missoula, MT, 59812, USA.,Center for Biomolecular Structure & Dynamics, University of Montana, Missoula, MT, 59812, USA
| | - Matthew J Sydor
- Department of Biomedical and Pharmaceutical Sciences, Center for Environmental Health Sciences, University of Montana, Missoula, MT, 59812, USA
| | - Donald S Anderson
- Department of Biomedical and Pharmaceutical Sciences, Center for Environmental Health Sciences, University of Montana, Missoula, MT, 59812, USA
| | - Andrij Holian
- Department of Biomedical and Pharmaceutical Sciences, Center for Environmental Health Sciences, University of Montana, Missoula, MT, 59812, USA
| | - J B Alexander Ross
- Department of Chemistry & Biochemistry, University of Montana, Missoula, MT, 59812, USA. .,Center for Biomolecular Structure & Dynamics, University of Montana, Missoula, MT, 59812, USA.
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Kováčik A, Vogel A, Adler J, Pullmannová P, Vávrová K, Huster D. Probing the role of ceramide hydroxylation in skin barrier lipid models by 2H solid-state NMR spectroscopy and X-ray powder diffraction. Biochim Biophys Acta Biomembr 2018; 1860:1162-1170. [PMID: 29408487 DOI: 10.1016/j.bbamem.2018.02.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Revised: 01/30/2018] [Accepted: 02/01/2018] [Indexed: 10/18/2022]
Abstract
In this work, we studied model stratum corneum lipid mixtures composed of the hydroxylated skin ceramides N-lignoceroyl 6-hydroxysphingosine (Cer[NH]) and α-hydroxylignoceroyl phytosphingosine (Cer[AP]). Two model skin lipid mixtures of the composition Cer[NH] or Cer[AP], N-lignoceroyl sphingosine (Cer[NS]), lignoceric acid (C24:0) and cholesterol in a 0.5:0.5:1:1 molar ratio were compared. Model membranes were investigated by differential scanning calorimetry and 2H solid-state NMR spectroscopy at temperatures from 25 °C to 80 °C. Each component of the model mixture was specifically deuterated for selective detection by 2H NMR. Thus, the exact phase composition of the mixture at varying temperatures could be quantified. Moreover, using X-ray powder diffraction we investigated the lamellar phase formation. From the solid-state NMR and DSC studies, we found that both hydroxylated Cer[NH] and Cer[AP] exhibit a similar phase behavior. At physiological skin temperature of 32 °C, the lipids form a crystalline (orthorhombic) phase. With increasing temperature, most of the lipids become fluid and form a liquid-crystalline phase, which converts to the isotropic phase at higher temperatures (65-80 °C). Interestingly, lignoceric acid in the Cer[NH]-containing mixture has a tendency to form two types of fluid phases at 65 °C. This tendency was also observed in Cer[AP]-containing membranes at 80 °C. While Cer[AP]-containing lipid models formed a short periodicity phase featuring a repeat spacing of d = 5.4 nm, in the Cer[NH]-based model skin lipid membranes, the formation of unusual long periodicity phase with a repeat spacing of d = 10.7 nm was observed.
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Affiliation(s)
- Andrej Kováčik
- Institute for Medical Physics and Biophysics, Leipzig University, Härtelstrasse 16-18, 04107 Leipzig, Germany; Skin Barrier Research Group, Faculty of Pharmacy in Hradec Králové, Charles University, Akademika Heyrovského 1203, 50005 Hradec Králové, Czech Republic
| | - Alexander Vogel
- Institute for Medical Physics and Biophysics, Leipzig University, Härtelstrasse 16-18, 04107 Leipzig, Germany
| | - Juliane Adler
- Institute for Medical Physics and Biophysics, Leipzig University, Härtelstrasse 16-18, 04107 Leipzig, Germany
| | - Petra Pullmannová
- Skin Barrier Research Group, Faculty of Pharmacy in Hradec Králové, Charles University, Akademika Heyrovského 1203, 50005 Hradec Králové, Czech Republic
| | - Kateřina Vávrová
- Skin Barrier Research Group, Faculty of Pharmacy in Hradec Králové, Charles University, Akademika Heyrovského 1203, 50005 Hradec Králové, Czech Republic.
| | - Daniel Huster
- Institute for Medical Physics and Biophysics, Leipzig University, Härtelstrasse 16-18, 04107 Leipzig, Germany.
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Aron M, Browning R, Carugo D, Sezgin E, Bernardino de la Serna J, Eggeling C, Stride E. Spectral imaging toolbox: segmentation, hyperstack reconstruction, and batch processing of spectral images for the determination of cell and model membrane lipid order. BMC Bioinformatics 2017; 18:254. [PMID: 28494801 PMCID: PMC5427590 DOI: 10.1186/s12859-017-1656-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2016] [Accepted: 04/26/2017] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Spectral imaging with polarity-sensitive fluorescent probes enables the quantification of cell and model membrane physical properties, including local hydration, fluidity, and lateral lipid packing, usually characterized by the generalized polarization (GP) parameter. With the development of commercial microscopes equipped with spectral detectors, spectral imaging has become a convenient and powerful technique for measuring GP and other membrane properties. The existing tools for spectral image processing, however, are insufficient for processing the large data sets afforded by this technological advancement, and are unsuitable for processing images acquired with rapidly internalized fluorescent probes. RESULTS Here we present a MATLAB spectral imaging toolbox with the aim of overcoming these limitations. In addition to common operations, such as the calculation of distributions of GP values, generation of pseudo-colored GP maps, and spectral analysis, a key highlight of this tool is reliable membrane segmentation for probes that are rapidly internalized. Furthermore, handling for hyperstacks, 3D reconstruction and batch processing facilitates analysis of data sets generated by time series, z-stack, and area scan microscope operations. Finally, the object size distribution is determined, which can provide insight into the mechanisms underlying changes in membrane properties and is desirable for e.g. studies involving model membranes and surfactant coated particles. Analysis is demonstrated for cell membranes, cell-derived vesicles, model membranes, and microbubbles with environmentally-sensitive probes Laurdan, carboxyl-modified Laurdan (C-Laurdan), Di-4-ANEPPDHQ, and Di-4-AN(F)EPPTEA (FE), for quantification of the local lateral density of lipids or lipid packing. CONCLUSIONS The Spectral Imaging Toolbox is a powerful tool for the segmentation and processing of large spectral imaging datasets with a reliable method for membrane segmentation and no ability in programming required. The Spectral Imaging Toolbox can be downloaded from https://uk.mathworks.com/matlabcentral/fileexchange/62617-spectral-imaging-toolbox .
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Affiliation(s)
- Miles Aron
- Department of Engineering Science, Institute of Biomedical Engineering, University of Oxford, Oxford, OX3 7DQ UK
| | - Richard Browning
- Department of Engineering Science, Institute of Biomedical Engineering, University of Oxford, Oxford, OX3 7DQ UK
| | - Dario Carugo
- Department of Engineering Science, Institute of Biomedical Engineering, University of Oxford, Oxford, OX3 7DQ UK
- Faculty of Engineering and The Environment, University of Southampton, Southampton, SO17 1BJ UK
| | - Erdinc Sezgin
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Headley Way, Oxford, OX3 9DS UK
| | - Jorge Bernardino de la Serna
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Headley Way, Oxford, OX3 9DS UK
- Research Complex at Harwell, Central Laser Facility, Rutherford Appleton Laboratory, Science and Technology Facilities Council, Harwell-Oxford, OX11 0FA UK
| | - Christian Eggeling
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Headley Way, Oxford, OX3 9DS UK
| | - Eleanor Stride
- Department of Engineering Science, Institute of Biomedical Engineering, University of Oxford, Oxford, OX3 7DQ UK
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Abstract
Membrane fluidity is a critical parameter of cellular membranes which cells continuously strive to maintain within a viable range. An interference with the correct membrane fluidity state can strongly inhibit cell function. Triggered changes in membrane fluidity have been postulated to contribute to the mechanism of action of membrane targeting antimicrobials, but the corresponding analyses have been hampered by the absence of readily available analytical tools. Here, we provide detailed protocols that allow straightforward measurement of antibiotic compound-triggered changes in membrane fluidity both in vivo and in vitro.
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Hishida M, Endo A, Nakazawa K, Yamamura Y, Saito K. Effect of n-alkanes on lipid bilayers depending on headgroups. Chem Phys Lipids 2015; 188:61-7. [PMID: 25957868 DOI: 10.1016/j.chemphyslip.2015.05.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Revised: 04/28/2015] [Accepted: 05/04/2015] [Indexed: 10/23/2022]
Abstract
Phase behavior and structural properties were examined for phospholipid bilayers having different headgroups (DMPC, DMPS and DMPE) with added n-alkanes to study effect of flexible additives. Change in the temperatures of main transition of the lipid/alkane mixtures against the length of added alkanes depends largely on the headgroup. Theoretical analysis of the change of the temperature of transition indicates that the headgroup dependence is dominantly originated in the strong dependence of total enthalpy on the headgroups. The results of X-ray diffraction show that the enthalpic stabilization due to enhanced packing of acyl chains of the lipid by alkanes in the gel phase causes the headgroup-dependent change in the phase transition behavior. The enhanced packing in the gel phase also leads to easy emergence of the subgel phase with very short relaxation time at room temperature in the DMPE-based bilayers.
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Affiliation(s)
- Mafumi Hishida
- Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan
| | - Asami Endo
- Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan
| | - Koyomi Nakazawa
- Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan
| | - Yasuhisa Yamamura
- Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan
| | - Kazuya Saito
- Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan.
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