Modulation of the Belousov–Zhabotinsky Reaction with Lipid Bilayers: Effects of Lipid Head Groups and Membrane Properties

Langmuir ◽  
2021 ◽  
Author(s):  
Michael S. Chern ◽  
Nozomi Watanabe ◽  
Keishi Suga ◽  
Yukihiro Okamoto ◽  
Hiroshi Umakoshi
Keyword(s):  
Lipid Bilayers ◽  
Membrane Properties ◽  
Head Groups ◽  
Belousov Zhabotinsky Reaction

Influence of Brain Gangliosides on the Formation and Properties of Supported Lipid Bilayers for Binding Kinetics Studies

2018 ◽  
Author(s):  
Luke Jordan ◽  
Nathan Wittenberg
Keyword(s):  
Lipid Bilayers ◽  
Binding Kinetics ◽  
Supported Lipid Bilayers ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Supported Lipid Bilayer ◽  
Head Groups ◽  
Lipid Diffusion ◽  
Kinetics Of ◽  
Brain Gangliosides

This is a comprehensive study of the effects of the four major brain gangliosides (GM1, GD1b, GD1a, and GT1b) on the adsorption and rupture of phospholipid vesicles on SiO2 surfaces for the formation of supported lipid bilayer (SLB) membranes. Using quartz crystal microbalance with dissipation monitoring (QCM-D) we show that gangliosides GD1a and GT1b significantly slow the SLB formation process, whereas GM1 and GD1b have smaller effects. This is likely due to the net ganglioside charge as well as the positions of acidic sugar groups on ganglioside glycan head groups. Data is included that shows calcium can accelerate the formation of ganglioside-rich SLBs. Using fluorescence recovery after photobleaching (FRAP) we also show that the presence of gangliosides significantly reduces lipid diffusion coefficients in SLBs in a concentration-dependent manner. Finally, using QCM-D and GD1a-rich SLB membranes we measure the binding kinetics of an anti-GD1a antibody that has similarities to a monoclonal antibody that is a hallmark of a variant of Guillain-Barre syndrome.

scholarly journals The Structural Integrity of the Model Lipid Membrane during Induced Lipid Peroxidation: The Role of Flavonols in the Inhibition of Lipid Peroxidation

Antioxidants ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 430 ◽  
Author(s):  
Anja Sadžak ◽  
Janez Mravljak ◽  
Nadica Maltar-Strmečki ◽  
Zoran Arsov ◽  
Goran Baranović ◽  
...  
Keyword(s):  
Lipid Peroxidation ◽  
Lipid Bilayers ◽  
Lipid Membranes ◽  
Structural Changes ◽  
Structural Integrity ◽  
Lipid Membrane ◽  
Membrane Properties ◽  
Structural Reorganization ◽  
Unsaturated Lipids ◽  
Oxidative Attack

The structural integrity, elasticity, and fluidity of lipid membranes are critical for cellular activities such as communication between cells, exocytosis, and endocytosis. Unsaturated lipids, the main components of biological membranes, are particularly susceptible to the oxidative attack of reactive oxygen species. The peroxidation of unsaturated lipids, in our case 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), induces the structural reorganization of the membrane. We have employed a multi-technique approach to analyze typical properties of lipid bilayers, i.e., roughness, thickness, elasticity, and fluidity. We compared the alteration of the membrane properties upon initiated lipid peroxidation and examined the ability of flavonols, namely quercetin (QUE), myricetin (MCE), and myricitrin (MCI) at different molar fractions, to inhibit this change. Using Mass Spectrometry (MS) and Fourier Transform Infrared Spectroscopy (FTIR), we identified various carbonyl products and examined the extent of the reaction. From Atomic Force Microscopy (AFM), Force Spectroscopy (FS), Small Angle X-Ray Scattering (SAXS), and Electron Paramagnetic Resonance (EPR) experiments, we concluded that the membranes with inserted flavonols exhibit resistance against the structural changes induced by the oxidative attack, which is a finding with multiple biological implications. Our approach reveals the interplay between the flavonol molecular structure and the crucial membrane properties under oxidative attack and provides insight into the pathophysiology of cellular oxidative injury.

Different Effects of Di- and Triphenyltin Compounds on Lipid Bilayer Dithionite Permeabilization

2000 ◽  
Vol 55 (9-10) ◽  
pp. 758-763 ◽  
Author(s):  
Janina Gabrielska ◽  
Teresa Kral ◽  
Marek Langner ◽  
Stanislaw Przestalski
Keyword(s):  
Molecular Structure ◽  
Lipid Bilayer ◽  
Lipid Bilayers ◽  
Membrane Properties ◽  
Human Environment ◽  
Vesicle Size ◽  
Phenyl Rings ◽  
Positively Charged ◽  
Steric Constraints ◽  
Quenching Assay

Abstract Phenyltins are chemicals widely used in industry, hence their occurrence in the human environment is frequent and widespread. Such compounds include hydrophobic phenyl rings bonded to positively charged tin. This molecular structure makes them capable of adsorbing onto and penetrating through biological membranes, hence they are potentially hazardous. Two such compounds, diphenyltin and triphenyltin, show different steric constraints when interacting with the lipid bilayer. It has been demonstrated that these compounds are positioned at different locations within model lipid bilayers, causing dissimilarity in their ability to affect membrane properties. In this paper we present a study regarding the ability of these two phenyltins to facilitate the transport of S2O4-2 ions across the lipid bilayer, evaluated by a fluorescence quenching assay. In concentration range of up-to 60 μm those compounds do not affect lipid bilayer topology, when evaluated by vesicle size distribution. Both phenyltins facilitate the transfer of S2O4-2 across the model lipid bilayer, but the dependence of dithionite transport on phenyltin concentration is different for both. In principle, above 20 μm triphenyltin is more efficient in transfering ions across the lipid bilayer than diphenyltin.

scholarly journals Characterization of Lipid Membrane Properties for Tunable Electroporation

2012 ◽  
Author(s):  
H. Jeremy Cho ◽  
Shalabh C. Maroo ◽  
Evelyn N. Wang
Keyword(s):  
Lipid Bilayers ◽  
Lipid Membrane ◽  
Contact Angle Measurement ◽  
Angle Measurement ◽  
Membrane Properties ◽  
Force Microscopy ◽  
Packing Structure ◽  
Atomic Force ◽  
Dynamics Simulations

Lipid bilayers form nanopores on the application of an electric field. This process of electroporation can be utilized in different applications ranging from targeted drug delivery in cells to nano-gating membrane for engineering applications. However, the ease of electroporation is dependent on the surface energy of the lipid layers and thus directly related to the packing structure of the lipid molecules. 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) lipid monolayers were deposited on a mica substrate using the Langmuir-Blodgett (LB) technique at different packing densities and analyzed using atomic force microscopy (AFM). The wetting behavior of these monolayers was investigated by contact angle measurement and molecular dynamics simulations. It was found that an equilibrium packing density of liquid-condensed (LC) phase DPPC likely exists and that water molecules can penetrate the monolayer displacing the lipid molecules. The surface tension of the monolayer in air and water was obtained along with its breakthrough force.

scholarly journals Purification, characterization and influence on membrane properties of the plant-specific sphingolipids GIPC

2020 ◽  
Author(s):  
Adiilah Mamode Cassim ◽  
Yotam Navon ◽  
Yu Gao ◽  
Marion Decossas ◽  
Laetitia Fouillen ◽  
...  
Keyword(s):  
Fluid Phase ◽  
Membrane Properties ◽  
Neutron Reflectivity ◽  
Temperature Variations ◽  
Signal Perception ◽  
H Nmr ◽  
Lipidomic Analysis ◽  
Outer Leaflet ◽  
Head Groups ◽  
Plant Plasma Membrane

AbstractThe plant plasma membrane (PM) is an essential barrier between the cell and the external environment. The PM is crucial for signal perception and transmission. It consists of an asymmetrical lipid bilayer made up of three different lipid classes: sphingolipids, sterols and phospholipids. The most abundant sphingolipids in the plant PM are the Glycosyl Inositol Phosphoryl Ceramides (GIPCs), representing up to 40% of total sphingolipids, assumed to be almost exclusively in the outer leaflet of the PM. In this study, we investigated the structure of GIPCs and their role in membrane organization. Since GIPCs are not commercially available, we developed a protocol to extract and isolate GIPC-enriched fractions from eudicots (cauliflower and tobacco) and monocots (leek and rice). Lipidomic analysis confirmed the presence of different long chain bases and fatty acids. The glycan head groups of the different GIPC series from monocots and dicots were analysed by GC-MS showing different sugar moieties. Multiple biophysics tools namely Langmuir monolayer, ζ-Potential, light scattering, neutron reflectivity, solid state 2H-NMR and molecular modelling were used to investigate the physical properties of the GIPCs, as well as their interaction with free and conjugated phytosterols. We showed that GIPCs increase the thickness and electronegativity of model membranes, interact differentially with the phytosterols species and regulate the gel-to-fluid phase transition during temperature variations.

scholarly journals Correlative microscopy reveals the nanoscale morphology of E. coli-derived supported lipid bilayers

2021 ◽  
Author(s):  
Karan Bali ◽  
Zeinab Mohamed ◽  
Anna-Maria Pappa ◽  
Susan Daniel ◽  
Clemens F. Kaminski ◽  
...  
Keyword(s):  
Lipid Bilayers ◽  
Lipid Membrane ◽  
Lipid Vesicles ◽  
Outer Membrane Vesicles ◽  
Atomic Scale ◽  
Membrane Properties ◽  
Supported Lipid Bilayers ◽  
Structured Illumination ◽  
Structured Illumination Microscopy ◽  
Natural And Synthetic

Supported lipid bilayers (SLBs) made from reconstituted lipid vesicles are an important tool in molecular biology. A breakthrough in the field has come with the use of vesicles derived from cell membranes to form SLBs. These new supported bilayers, consisting both of natural and synthetic components, provide a physiologically relevant system on which to study protein-protein interactions as well as protein-ligand interactions and other lipid membrane properties. These complex bilayer systems hold promise but have not yet been fully characterised in terms of their composition, ratio of natural to synthetic component and membrane protein content. Here, we describe a method of correlative atomic force (AFM) with structured illumination microscopy (SIM) for the accurate mapping of complex lipid bilayers that consist of a synthetic fraction and a fraction of lipids derived from Escherichia coli outer membrane vesicles (OMVs). We exploit the enhanced resolution and molecular specificity that SIM can offer to identify areas of interest in these bilayers and the atomic scale resolution that the AFM provides to create detailed topography maps of the bilayers. We are thus able to understand the way in which the two different lipid fractions (natural and synthetic) mix within the bilayers, quantify the amount of bacterial membrane incorporated in the bilayer and directly visualise the interaction of these bilayers with bacteria-specific, membrane-binding proteins. Our work sets the foundation for accurately understanding the composition and properties of OMV-derived SLBs and establishes correlative AFM/ SIM as a method for characterising complex systems at the nanoscale.

Influence of Brain Gangliosides on the Formation and Properties of Supported Lipid Bilayers for Binding Kinetics Studies

2018 ◽  
Author(s):  
Luke Jordan ◽  
Nathan Wittenberg
Keyword(s):  
Lipid Bilayers ◽  
Binding Kinetics ◽  
Supported Lipid Bilayers ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Supported Lipid Bilayer ◽  
Head Groups ◽  
Lipid Diffusion ◽  
Kinetics Of ◽  
Brain Gangliosides

This is a comprehensive study of the effects of the four major brain gangliosides (GM1, GD1b, GD1a, and GT1b) on the adsorption and rupture of phospholipid vesicles on SiO2 surfaces for the formation of supported lipid bilayer (SLB) membranes. Using quartz crystal microbalance with dissipation monitoring (QCM-D) we show that gangliosides GD1a and GT1b significantly slow the SLB formation process, whereas GM1 and GD1b have smaller effects. This is likely due to the net ganglioside charge as well as the positions of acidic sugar groups on ganglioside glycan head groups. Data is included that shows calcium can accelerate the formation of ganglioside-rich SLBs. Using fluorescence recovery after photobleaching (FRAP) we also show that the presence of gangliosides significantly reduces lipid diffusion coefficients in SLBs in a concentration-dependent manner. Finally, using QCM-D and GD1a-rich SLB membranes we measure the binding kinetics of an anti-GD1a antibody that has similarities to a monoclonal antibody that is a hallmark of a variant of Guillain-Barre syndrome.

scholarly journals Terminal lipophilization of a unique DNA dodecamer by various nucleolipid headgroups: Their incorporation into artificial lipid bilayers and hydrodynamic properties

2015 ◽  
Vol 11 ◽  
pp. 913-929 ◽  
Author(s):  
Emma Werz ◽  
Helmut Rosemeyer
Keyword(s):  
Lipid Bilayer ◽  
Lipid Bilayers ◽  
Single Molecule ◽  
Head Group ◽  
Artificial Lipid Bilayers ◽  
Decisive Importance ◽  
Head Groups ◽  
Single Molecule Fluorescence Spectroscopy ◽  
Dna Dodecamer ◽  
And Diffusion

A series of six cyanine-5-labeled oligonucleotides (LONs 10–15), each terminally lipophilized with different nucleolipid head groups, were synthesized using the recently prepared phosphoramidites 4b–9b. The insertion of the LONs within an artificial lipid bilayer, composed of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE), was studied by single molecule fluorescence spectroscopy and microscopy with the help of an optically transparent microfluidic sample carrier with perfusion capabilities. The incorporation of the lipo-oligonucleotides into the bilayer was studied with respect to efficiency (maximal bilayer brightness) as well as stability against perfusion (final stable bilayer brightness). Attempts to correlate these parameters with the log P values of the corresponding nucleolipid head groups failed, a result which clearly demonstrates that not only the lipophilicity but mainly the chemical structure and topology of the head group is of decisive importance for the optimal interaction of a lipo-oligonucleotide with an artificial lipid bilayer. Moreover, fluorescence half-live and diffusion time values were measured to determine the diffusion coefficients of the lipo-oligonucleotides.

scholarly journals Receptor-independent membrane mediated pathways of serotonin action

2020 ◽  
Author(s):  
Simli Dey ◽  
Dayana Surendran ◽  
Oskar Enberg ◽  
Ankur Gupta ◽  
Sashaina E. Fanibunda ◽  
...  
Keyword(s):  
Lipid Bilayers ◽  
Pancreatic Beta Cells ◽  
Serotonin Receptor ◽  
Lipid Membrane ◽  
Neuronal Cell ◽  
Membrane Properties ◽  
Islet Amyloid ◽  
Cellular Effects ◽  
Cellular Processes ◽  
Artificial Lipid Bilayers

AbstractSerotonin is a neurotransmitter as well as a somatic signaling molecule, and the serotonergic system is a major target for psychotropic drugs. Serotonin, together with a few related neurotransmitters, has recently been found to exhibit an unexpectedly high lipid membrane affinity1–3. It has been conjectured that extrasynaptic serotonin can diffuse in the lipid membrane to efficiently reach remote receptors (and receptors with buried ligand-binding sites)4, providing a mechanism for the diffuse ‘volume’ neurotransmission that serotonin is capable of5–10. Here we show that membrane binding by serotonin can directly modulate membrane properties and cellular function, independent of its receptor-mediated actions. Atomic force microscopy shows that serotonin binding makes artificial lipid bilayers softer. It induces nucleation of liquid disordered domains inside the raft-like liquid-ordered domains in a ternary bilayer displaying phase separation. Solid-state NMR spectroscopy corroborates this data, revealing a rather homogeneous decrease in the order parameter of the lipid chains in the presence of serotonin. In the RN46A immortalized serotonergic neuronal cell line, extracellular serotonin enhances transferrin receptor endocytosis, an action exerted even in the presence of both broad-spectrum serotonin receptor and transporter inhibitors. Similarly, it increases the binding and internalization of Islet Amyloid Polypeptide (IAPP) oligomers, suggesting a connection between serotonin, which is co-secreted with IAPP by pancreatic beta cells, and the cellular effects of IAPP. Our results uncover a hitherto unknown serotonin-bilayer interaction that can potentiate key cellular processes in a receptor-independent fashion. Therefore, some pathways of serotonergic action may escape potent pharmaceutical agents designed for serotonin transporters or receptors. Conversely, bio-orthogonal serotonin-mimetics may provide a new class of cell-membrane modulators.

scholarly journals Investigating the Lipid Selectivity of the Ammonium Transporter AmtB in Heterogeneous Nanodiscs

2021 ◽  
Author(s):  
James E. Keener ◽  
Michael T Marty
Keyword(s):  
Lipid Bilayers ◽  
Tight Binding ◽  
Native Mass Spectrometry ◽  
Ammonium Transporter ◽  
Lipid Interactions ◽  
Head Groups ◽  
Bound Lipids ◽  
Lipid Environment ◽  
And Function ◽  
Triton X

The structure and function of membrane proteins can be significantly impacted by the surrounding lipid environment, but membrane protein-lipid interactions in lipid bilayers are often difficult to study due to their transient and polydisperse nature. Here, we used two native mass spectrometry (MS) approaches to investigate how the Escherichia coli ammonium transporter (AmtB) selectively remodels its local lipid environment in heterogeneous lipoprotein nanodiscs. First, we used gas-phase ejection to isolate AmtB with bound lipids from heterogeneous nanodiscs with different combinations of lipids. Second, we used solution-phase detergent flash extraction as an orthogonal approach to study AmtB remodeling with native MS. Flash extraction of AmtB showed that Triton X-100 retains lipid selectivity, but C8E4 distorts preferential lipid interactions. Both approaches reveal that AmtB has a few tight binding sites for PC, is selective for binding PG over-all, and is nonselective for PE, providing a detailed picture of how AmtB binds different lipid head groups in the context of mixed lipid bilayers.

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