scholarly journals Study of Resveratrol’s Interaction with Planar Lipid Models: Insights into Its Location in Lipid Bilayers

Membranes ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 132 ◽  
Author(s):  
Daniela Meleleo
Keyword(s):  
Lipid Bilayers ◽  
Lipid Membranes ◽  
Fruits And Vegetables ◽  
Water Solubility ◽  
Membrane Lipids ◽  
Biophysical Parameters ◽  
Beneficial Effects ◽  
Wide Range ◽  
Aging Properties ◽  
Electrophysiological Measurements

Resveratrol, a polyphenolic molecule found in edible fruits and vegetables, shows a wide range of beneficial effects on human health, including anti-microbial, anti-inflammatory, anti-cancer, and anti-aging properties. Due to its poor water solubility and high liposome-water partition coefficient, the biomembrane seems to be the main target of resveratrol, although the mode of interaction with membrane lipids and its location within the cell membrane are still unclear. In this study, using electrophysiological measurements, we study the interaction of resveratrol with planar lipid membranes (PLMs) of different composition. We found that resveratrol incorporates into palmitoyl-oleoyl-phosphatidylcholine (POPC) and POPC:Ch PLMs and forms conductive units unlike those found in dioleoyl-phosphatidylserine (DOPS):dioleoyl-phosphatidylethanolamine (DOPE) PLMs. The variation of the biophysical parameters of PLMs in the presence of resveratrol provides information on its location within a lipid double layer, thus contributing to an understanding of its mechanism of action.

scholarly journals Modulation of physiological and pathological activities of lysozyme by biological membranes

2012 ◽  
Vol 17 (3) ◽  
Author(s):  
Valeriya Trusova
Keyword(s):  
Lipid Bilayers ◽  
Lipid Membranes ◽  
Dynamic Properties ◽  
Biological Activities ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Lipid Vesicles ◽  
Bacterial Cells ◽  
Oligomeric Protein ◽  
Wide Range

AbstractThe molecular details of interactions between lipid membranes and lysozyme (Lz), a small polycationic protein with a wide range of biological activities, have long been the focus of numerous studies. The biological consequences of this process are considered to embrace at least two aspects: i) correlation between antimicrobial and membranotropic properties of this protein, and ii) lipid-mediated Lz amyloidogenesis. The mechanisms underlying the lipid-assisted protein fibrillogenesis and membrane disruption exerted by Lz in bacterial cells are believed to be similar. The present investigation was undertaken to gain further insight into Lz-lipid interactions and explore the routes by which Lz exerts its antimicrobial and amyloidogenic actions. Binding and Förster resonance energy transfer studies revealed that upon increasing the content of anionic lipids in lipid vesicles, Lz forms aggregates in a membrane environment. Total internal reflection fluorescence microscopy and pyrene excimerization reaction were employed to study the effect of Lz on the structural and dynamic properties of lipid bilayers. It was found that Lz induces lipid demixing and reduction of bilayer free volume, the magnitude of this effect being much more pronounced for oligomeric protein.

scholarly journals Dynamic “Molecular Portraits” of Biomembranes Drawn by Their Lateral Nanoscale Inhomogeneities

2021 ◽  
Vol 22 (12) ◽  
pp. 6250
Author(s):  
Roman G. Efremov
Keyword(s):  
Lipid Bilayers ◽  
Lipid Membranes ◽  
Rational Design ◽  
Cell Membranes ◽  
Molecular Mechanisms ◽  
Water Interface ◽  
Structural Dynamic ◽  
In Silico Studies ◽  
Wide Range ◽  
Component Cell

To date, it has been reliably shown that the lipid bilayer/water interface can be thoroughly characterized by a sophisticated so-called “dynamic molecular portrait”. The latter reflects a combination of time-dependent surface distributions of various physicochemical properties, inherent in both model lipid bilayers and natural multi-component cell membranes. One of the most important features of biomembranes is their mosaicity, which is expressed in the constant presence of lateral inhomogeneities, the sizes and lifetimes of which vary in a wide range—from 1 to 103 nm and from 0.1 ns to milliseconds. In addition to the relatively well-studied macroscopic domains (so-called “rafts”), the analysis of micro- and nanoclusters (or domains) that form an instantaneous picture of the distribution of structural, dynamic, hydrophobic, electrical, etc., properties at the membrane-water interface is attracting increasing interest. This is because such nanodomains (NDs) have been proven to be crucial for the proper membrane functioning in cells. Therefore, an understanding with atomistic details the phenomena associated with NDs is required. The present mini-review describes the recent results of experimental and in silico studies of spontaneously formed NDs in lipid membranes. The main attention is paid to the methods of ND detection, characterization of their spatiotemporal parameters, the elucidation of the molecular mechanisms of their formation. Biological role of NDs in cell membranes is briefly discussed. Understanding such effects creates the basis for rational design of new prospective drugs, therapeutic approaches, and artificial membrane materials with specified properties.

scholarly journals Determination of bending rigidity and tilt modulus of lipid membranes from real-space fluctuation analysis of molecular dynamics simulations

2017 ◽  
Vol 19 (25) ◽  
pp. 16806-16818 ◽  
Author(s):  
M. Doktorova ◽  
D. Harries ◽  
G. Khelashvili
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Lipid Bilayers ◽  
Lipid Membranes ◽  
Real Space ◽  
Fluctuation Analysis ◽  
Bending Rigidity ◽  
Wide Range ◽  
Dynamics Simulations

Computational methodology that allows to extract bending rigidity and tilt modulus for a wide range of single and multi-component lipid bilayers from real-space analysis of fluctuations in molecular dynamics simulations.

A Critical Analysis of Quercetin as the Attractive Target for the Treatment of Parkinson's Disease

2021 ◽  
Vol 20 ◽  
Author(s):  
Ozlem Bahadır Acıkara ◽  
Gökçe Şeker Karatoprak ◽  
Çiğdem Yücel ◽  
Esra Küpeli Akkol ◽  
Eduardo Sobarzo-Sánchez ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Fruits And Vegetables ◽  
Water Solubility ◽  
Neuroprotective Effect ◽  
Complementary Therapy ◽  
Neuroprotective Activity ◽  
Beneficial Effects ◽  
Neuroprotective Actions

: Parkinson's disease (PD) is a multifaceted disorder with various factors that have been suggested to play a synergistic pathophysiological role, such as oxidative stress, autophagy, pro-inflammatory events, and neurotransmitter abnormalities. While it is crucial to discover new treatments in addition to preventing PD, recent studies have focused on determining whether nutraceuticals will exert neuroprotective actions and pharmacological functions in PD. Quercetin, a flavonol- type flavonoid, is found in many fruits and vegetables and has been recognized as a complementary therapy for PD. The neuroprotective effect of quercetin is directly associated with its antioxidant activity, in addition to stimulating cellular defense against oxidative stress. Other related mechanisms are activating sirtuins (SIRT1) and inducing autophagy, in addition to induction of Nrf2-ARE and paraoxonase 2 (PON2). Quercetin, whose neuroprotective activity has been demonstrated in many studies, unfortunately, has a disadvantage because of its poor water solubility, chemical instability, and low oral bioavailability. It has been reported that the disadvantages of quercetin have been eliminated in studies with nanocarriers loaded with quercetin. The role of nanotechnology and nanodelivery systems in reducing oxidative stress during PD provides an indisputable advantage. Accordingly, the aim of the present review is to shed light on the beneficial effects and underlying mechanisms of quercetin in neuroprotection. In addition, the contribution of nanodelivery systems to the neuroprotective effect of quercetin will be discussed.

scholarly journals Direct proof of spontaneous translocation of lipid-covered hydrophobic nanoparticles through a phospholipid bilayer

2016 ◽  
Vol 2 (11) ◽  
pp. e1600261 ◽  
Author(s):  
Yachong Guo ◽  
Emmanuel Terazzi ◽  
Ralf Seemann ◽  
Jean Baptiste Fleury ◽  
Vladimir A. Baulin
Keyword(s):  
Lipid Bilayers ◽  
Lipid Membranes ◽  
Direct Proof ◽  
Phospholipid Bilayer ◽  
In Situ Observation ◽  
Threshold Size ◽  
Translocation Event ◽  
Electrophysiological Measurements ◽  
Translocation Mechanism ◽  
Optical Fluorescence

Hydrophobic nanoparticles introduced into living systems may lead to increased toxicity, can activate immune cells, or can be used as nanocarriers for drug or gene delivery. It is generally accepted that small hydrophobic nanoparticles are blocked by lipid bilayers and accumulate in the bilayer core, whereas big nanoparticles can only penetrate cells through slow energy-dependent processes, such as endocytosis, lasting minutes. In contrast to expectations, we demonstrate that lipid-covered hydrophobic nanoparticles may translocate through lipid membranes by direct penetration within milliseconds. We identified the threshold size for translocation: nanoparticles with diameters smaller than 5 nm stay trapped in the bilayer, whereas those with diameters larger than 5 nm insert into the bilayer, opening pores in the bilayer. The direct proof of this size-dependent translocation was provided by an in situ observation of a single event of a nanoparticle quitting the bilayer. This was achieved with a specially designed microfluidic device combining optical fluorescence microscopy with simultaneous electrophysiological measurements. A quantitative analysis of the kinetic pathway of a single nanoparticle translocation event demonstrated that the translocation is irreversible and that the nanoparticle can translocate only once. This newly discovered one-way translocation mechanism provides numerous opportunities for biotechnological applications, ranging from targeted biomaterial elimination and/or delivery to precise and controlled trapping of nanoparticles.

Investigating the Function of Ion Channels in Tethered Lipid Membranes by Impedance Spectroscopy

MRS Bulletin ◽  
2005 ◽  
Vol 30 (3) ◽  
pp. 207-210 ◽  
Author(s):  
Samuel Terrettaz ◽  
Horst Vogel
Keyword(s):  
Ion Channels ◽  
Impedance Spectroscopy ◽  
Ligand Binding ◽  
Lipid Bilayers ◽  
Lipid Membranes ◽  
Gold Electrodes ◽  
Channel Activity ◽  
Electrophysiological Measurements ◽  
Supported Lipid Membranes ◽  
Specific Ligand

AbstractThe function of biologically important ion channels can be measured in supported lipid membranes by impedance spectroscopy. This approach offers substantial advantages over traditional electrophysiological measurements. In this article, we present an overview of the field, with a special emphasis on the reconstitution of ion channels in lipid bilayers tethered to gold electrodes and the modulation of their channel activity by specific ligand binding.

High-Pressure Effects on the Structure and Phase Behavior of Model Membrane Systems

1996 ◽  
Author(s):  
Roland Winter ◽  
Anne Landwehr
Keyword(s):  
High Pressure ◽  
Phase Behavior ◽  
Lipid Bilayers ◽  
Lipid Membranes ◽  
Membrane Lipids ◽  
Pressure Effects ◽  
Scanning Calorimetry ◽  
Hydrocarbon Chains ◽  
Temperature And Pressure ◽  
Lipid Conformation

Phospholipids, which provide valuable model systems for lipid membranes, display a variety of polymorphic phases, depending on their molecular structure and on environmental conditions. High hydrostatic pressure has been used as a physical parameter to study the thermodynamic properties and phase behavior of these systems. High pressure is also a characteristic feature of certain natural membrane environments. In the first part of this article, we review our recent work on the temperature- and pressure-dependent phase behavior of phospholipid systems differing in lipid conformation and headgroup structure. In the second part, we report on the determination of the (T, x, p) phase diagrams of binary phospholipid mixtures. An additional section deals with effects of incorporating ions, small amphiphilic molecules, and steroids into the bilayer on the experimental temperature- and pressure-dependent phase behavior of lipid systems. Finally, we discuss lamellar to nonlamellar thermotropic and barotropic phase transformations, which occur for a number of lipids, such as phosphatidylethanolamines, monoacylglycerides, and lipid mixtures. It has been suggested that nonlamellar lipid structures might play an important role as transient and local intermediates in a number of biochemical processes. High-pressure smallangle x-ray (SAXS) and neutron (SANS) scattering, differential scanning calorimetry (DSC), high-pressure differential thermal analysis (DTA), and p, V, T measurements have been used as experimental methods for the investigation of these systems. Lipid bilayer dispersions, in particular the phosphatidylcholines and phosphatidylethanolamines, are the workhorses for the investigation of biophysical properties of membrane lipids because they constitute the basic structural component of biological membranes. They exhibit a rich lyotropic and thermotropic phase behavior (Cevc & Marsh, 1987; Marsh, 1991; Yeagle, 1992). Most fully hydrated saturated phospholipid bilayers exhibit two principal thermotropic lamellar phase transitions, corresponding to a gel to gel (Lβ′–Pβ′) transition and a gel to liquid-crystalline (Pβ′–Lα) main transition at a temperature Tm. In the fluid-like La phase, the hydrocarbon chains of the lipid bilayers are conformationally disordered, whereas in the gel phases the hydrocarbon chains are more extended and relatively ordered.

scholarly journals Use of Alginates as Food Packaging Materials

Foods ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 1440
Author(s):  
Michael G. Kontominas
Keyword(s):  
Food Packaging ◽  
Fruits And Vegetables ◽  
Water Solubility ◽  
Negative Impact ◽  
Whey Proteins ◽  
Mechanical Damage ◽  
Food Product ◽  
Packaging Materials ◽  
Renewable Materials ◽  
Wide Range

Packaging mainly functions by protecting and preserving its contents. In the case of food packaging, the package protects the contained food product from (i) physical/mechanical damage; (ii) physico-chemical changes due to the effect of light, oxygen, moisture and odors; and (iii) biological changes due to the presence of microorganisms and pests; all the above parameters result in the reduction in product quality and safety. Due to the negative impact of synthetic packaging materials on the environment, research organizations as well as the food industry are currently exploring the possibility of using biodegradable and renewable materials deriving from natural sources. Such biopolymers include: proteins (whey proteins, wheat, corn and soy proteins, gelatin), lipid derivatives (waxes, acetylated triglycerides) and carbohydrates (starch, cellulose and its derivatives, carrageenan, pectin, chitosan, alginates) used in food packaging applications. Alginates are natural hydrophilic polysaccharide biopolymers mainly extracted from marine brown algae. In the form of films or coatings, they exhibit: good film-forming properties, low permeability to O2 and vapors, flexibility, water solubility and gloss while being tasteless and odorless. When combined with additives such as organic acids, essential oils, plant extracts, bacteriocins and nanomaterials, they contribute to the retention of moisture, reduction in shrinkage, retardation of oxidation, inhibition of color and texture degradation, reduction in microbial load, enhancement of sensory acceptability and minimization of cooking losses. Alginates were initially used as a coating for perishable fresh fruits and vegetables to control respiration rate, but can be applied to a wide range of foods, such as meat, poultry, seafood and cheese products, resulting in the extension of product shelf life. When used as part of the principle of active, intelligent and green packaging technologies, alginates can work synergistically to yield a multi-function food packaging system comprising the ultimate goal of food packaging technology.

scholarly journals Fluorescence Approaches for Characterizing Ion Channels in Synthetic Bilayers

Membranes ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 857
Author(s):  
Md. Sirajul Islam ◽  
James P. Gaston ◽  
Matthew A. B. Baker
Keyword(s):  
Ion Channels ◽  
Membrane Proteins ◽  
Lipid Bilayers ◽  
Lipid Membranes ◽  
Protein Composition ◽  
Cellular Processes ◽  
Model Lipid Membranes ◽  
Wide Range ◽  
Lipid Environment

Ion channels are membrane proteins that play important roles in a wide range of fundamental cellular processes. Studying membrane proteins at a molecular level becomes challenging in complex cellular environments. Instead, many studies focus on the isolation and reconstitution of the membrane proteins into model lipid membranes. Such simpler, in vitro, systems offer the advantage of control over the membrane and protein composition and the lipid environment. Rhodopsin and rhodopsin-like ion channels are widely studied due to their light-interacting properties and are a natural candidate for investigation with fluorescence methods. Here we review techniques for synthesizing liposomes and for reconstituting membrane proteins into lipid bilayers. We then summarize fluorescence assays which can be used to verify the functionality of reconstituted membrane proteins in synthetic liposomes.

scholarly journals The Mechanisms of Action of Triindolylmethane Derivatives on Lipid Membranes

Acta Naturae ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 38-45 ◽  
Author(s):  
S. S. Efimova ◽  
T. E. Tertychnaya ◽  
S. N. Lavrenov ◽  
O. S. Ostroumova
Keyword(s):  
Lipid Bilayers ◽  
Lipid Membranes ◽  
Antibacterial Agents ◽  
Membrane Lipids ◽  
Mechanisms Of Action ◽  
Electrical Stability ◽  
Membrane Breakdown ◽  
Model Lipid Membranes ◽  
Transmembrane Pores ◽  
The Difference

The effects of new synthetic antibacterial agents - tris(1-pentyl-1H-indol-3-yl)methylium chloride (LCTA-1975) and (1-(4-(dimethylamino)-2,5-dioxo-2,5-dihydro-1H-pyrrol-3-yl)-1H-indol-3-yl)bis(1-propyl- 1H-indol-3-yl)methylium chloride (LCTA-2701 - on model lipid membranes were studied. The ability of the tested agents to form ion-conductive transmembrane pores, influence the electrical stability of lipid bilayers and the phase transition of membrane lipids, and cause the deformation and fusion of lipid vesicles was investigated. It was established that both compounds exert a strong detergent effect on model membranes. The results of differential scanning microcalorimetry and measuring of the threshold transmembrane voltage that caused membrane breakdown before and after adsorption of LCTA-1975 and LCTA-2701 indicated that both agents cause disordering of membrane lipids. Synergism of the uncoupling action of antibiotics and the alkaloid capsaicin on model lipid membranes was shown. The threshold concentration of the antibiotic that caused an increase in the ion permeability of the lipid bilayer depended on the membrane lipid composition. It was lower by an order of magnitude in the case of negatively charged lipid bilayers than for the uncharged membranes. This can be explained by the positive charge of the tested agents. At the same time, LCTA-2701 was characterized by greater efficiency than LCTA-1975. In addition to its detergent action, LCTA-2701 can induce ion-permeable transmembrane pores: step-like current fluctuations corresponding to the opening and closing of individual ion channels were observed. The difference in the mechanisms of action might be related to the structural features of the antibiotic molecules: in the LCTA-1975 molecule, all three substituents at the nitrogen atoms of the indole rings are identical and represent n-alkyl (pentyl) groups, while LCTA-2701 contains a maleimide group, along with two alkyl substituents (n-propyl). The obtained results might be relevant to our understanding of the mechanism of action of new antibacterial agents, explaining the difference in the selectivity of action of the tested agents on the target microorganisms and their toxicity to human cells. Model lipid membranes should be used in further studies of the trends in the modification and improvement of the structures of new antibacterial agents.

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