Search results for "phospholipids"
showing 10 items of 197 documents
Plant virus cell-to-cell movement is not dependent on the transmembrane disposition of its movement protein
2009
ABSTRACT The cell-to-cell transport of plant viruses depends on one or more virus-encoded movement proteins (MPs). Some MPs are integral membrane proteins that interact with the membrane of the endoplasmic reticulum, but a detailed understanding of the interaction between MPs and biological membranes has been lacking. The cell-to-cell movement of the Prunus necrotic ringspot virus (PNRSV) is facilitated by a single MP of the 30K superfamily. Here, using a myriad of biochemical and biophysical approaches, we show that the PNRSV MP contains only one hydrophobic region (HR) that interacts with the membrane interface, as opposed to being a transmembrane protein. We also show that a proline resi…
Double layer potential and degree of dissociation in charged lipid monolayers
2000
Abstract One of the contributions to the surface potential in charged phospholipid monolayers at air–water interfaces is the double layer potential. In this note several misconceptions found in the literature concerning the relationship between the double layer potential and the degree of dissociation of the lipid polar headgroups are critically analyzed. The deviations of the double layer potential measurements from the Gouy–Chapman theory observed by several authors are explained by taking into account the dependence of the degree of dissociation with concentration, area per lipid molecule and pH.
Release of choline in the isolated heart, an indicator of ischemic phospholipid degradation and its protection by ischemic preconditioning: No eviden…
2003
Abstract The release of choline as a water-soluble product of phospholipid hydrolysis was measured in the perfusate of rat hearts to monitor ischemic membrane degradation and its protection by ischemic preconditioning (IPC). Hearts were subjected to global ischemia (GI; 30 min of no-flow) followed by 60 min of reperfusion. To induce IPC, GI was preceded by four no-flow episodes of 5 min each. Deleterious consequences of GI and reperfusion, namely coronary flow reduction, incidence of arrhythmias and release of cardiac troponin T, were significantly attenuated by IPC. The release of choline increased during reperfusion in a biphasic manner: a first phase peaked immediately after GI and was f…
Thymus essential oil extraction, characterization and incorporation in phospholipid vesicles for the antioxidant/antibacterial treatment of oral cavi…
2018
The aim of the work was to extract, characterize, and formulate Thymus capitatus (Tymbra capitata) essential oil in phospholipid vesicles: liposomes, glycerosomes and Penetration Enhancer-containing Vesicles (PEVs). The steam-distilled essential oil was mainly composed of carvacrol. The oil was mixed with lecithin and water to produce liposomes, or different ratios of water/glycerol or water/propylene glycol (PG) to produce glycerosomes and PG-PEVs, respectively. Cryo-TEM showed the formation of unilamellar, spherical vesicles, and light scattering disclosed that their size increased in the presence of glycerol or PG, which improved long-term stability. The formulations were highly biocompa…
Scanning electrochemical microscopy as a probe of Ag+ binding kinetics at Langmuir phospholipid monolayers
2005
A new method has been developed for measuring local adsorption rates of metal ions at interfaces based on scanning electrochemical microscopy (SECM). The technique is illustrated with the example of Ag+ binding at Langmuir phospholipid monolayers formed at the water/air interface. Specifically, an inverted 25 microm diameter silver disc ultramicroelectrode (UME) was positioned in the subphase of a Langmuir trough, close to a dipalmitoyl phosphatidic acid (DPPA) monolayer, and used to generate Ag+ via Ag electro-oxidation. The method involved measuring the transient current-time response at the UME when the electrode was switched to a potential to electrogenerate Ag+. Since the Ag+/Ag couple…
Pulmonary surfactant protein C containing lipid films at the air-water interface as a model for the surface of lung alveoli.
1995
The pulmonary surfactant lines as a complex monolayer of lipids and proteins the alveolar epithelial surface. The monolayer dynamically adapts the surface tension of this interface to the varying surface areas during inhalation and exhalation. Its presence in the alveoli is thus a prerequisite for a proper lung function. The lipid moiety represents about 90% of the surfactant and contains mainly dipalmitoylphosphatidylcholine (DPPC) and phosphatidylglycerol (PG). The surfactant proteins involved in the surface tension adaption are called SP-A, SP-B and SP-C. The aim of the present investigation is to analyse the properties of monolayer films made from pure SP-C and from mixtures of DPPC, DP…
Exploring the co-loading of lidocaine chemical forms in surfactant/phospholipid vesicles for improved skin delivery
2015
Abstract Objectives The present study was aimed at targeting the skin to deliver lidocaine loaded in surfactant/phospholipid vesicles tailored for improved local delivery. The influence of different formulation parameters was explored to maximise drug efficacy. Methods The vesicles were prepared using a mixture of soy lipids (Phospholipon 50) and a surfactant with penetration-enhancing properties (Oramix CG110, Labrasol, Labrafac PG or Labrafac CC), and loaded with lidocaine. The formulations were analysed in detail by cryo-TEM, SAXS, Turbiscan Lab, and tested in permeation experiments through new born pig skin, as a function of the chemical form and concentration of lidocaine (i.e. free ba…
Spectrophotometric evidence for the solubilization site of betalain pigments in membrane biomimetic systems.
2007
The solubilization site of two betalain pigments, namely, betanin and indicaxantin, into l-alpha-dipalmitoyl-phosphatidylcholine (DPPC) and dimyristoylphosphatidylcholine (DMPC) vesicles was investigated by a spectrophotometric study. Pigment absorbance was monitored by varying phospholipid concentration, at a constant temperature that was varied in a range including the main phase transition temperature (Tm) of the relevant phospholipid bilayer. Maximum betanin absorption increased with the increase of DPPC concentration within the entire temperature range, reaching a plateau. The binding constant (Kb) of the pigment, calculated according to a pseudo-two-phase model, varied with the temper…
In situ synthesis of lipopeptides as versatile receptors for the specific binding of nanoparticles and liposomes to solid-supported membranes.
2008
A detailed study of the in situ coupling of small peptides such as CGGH6 (H6) and CGWK8 (K8) to maleimide functionalized phospholipid bilayers is presented. Individually addressable microstructured membranes are employed to unequivocally probe the conjugation. The in situ coupling of peptides via a terminal cysteine moiety to maleimide functionalized phospholipids is shown to be a convenient and versatile way to selectively fabricate peptide-modified phospholipid bilayers serving as specific receptor platforms for functionalized vesicles and nanoparticles. Specific binding of functional vesicles to the peptide-modified bilayers is achieved by either histidine complexation with Ni-NTA-DOGS c…
Evaluation of the toxicity of mussels from 2 sites of the Moroccan Atlantic Coast (Jorf Lasfar and Oualidia) used as bioindicators of contamination :…
2012
Toxic substances generated by various human activities are spilled on different area of the Moroccan coast. Shellfishes can concentrate pollutants and have some adverse effects on human health through the food chain. Despite the strengthening of food safety rules, the involvement of chemical pollution of food on metabolic disorders is not known. To predict the impact of pollutants on the aquatic ecosystem and human health, the development of appropriate biomonitoring tools is required.We quantified heavy metals (Cd, Cr and Pb) in mussels (Mytilus galloprovincialis) from two sites of Moroccan Atlantic coast (industrial site Jorf Lasfar (JL) and touristic site Oualidia (OL)) due to the proxim…