Two-photon fluorescence microscopy observation of shape changes at the phase transition in phospholipid giant unilamellar vesicles.
AuthorsBagatolli LA, Gratton E
JournalBiophys J
PubMed ID10512829
'Using the sectioning effect of the two-photon fluorescence microscope, we studied the behavior of phospholipid giant unilamellar vesicles (GUVs) composed of pure diacylphosphatidylcholine phospholipids during the gel-to-liquid crystalline phase transition. We used the well-characterized excitation generalized polarization function (GP(ex)) of 6-dodecanoyl-2-dimethylamine-naphthalene (LAURDAN), which is sensitive to the changes in water ... More
Physical properties of erythrocyte ghosts that determine susceptibility to secretory phospholipase A2.
AuthorsHarris FM, Smith SK, Bell JD
JournalJ Biol Chem
PubMed ID11294853
'Artificial membranes may be resistant or susceptible to catalytic attack by secretory phospholipase A(2) (sPLA(2)) depending on the physical properties of the membrane. Living cells are normally resistant but become susceptible during trauma, apoptosis, and/or a significant elevation of intracellular calcium. Intact erythrocytes and ghosts were studied to determine whether ... More
Comparative benzene-induced fatty acid changes in a Rhodococcus species and its benzene-sensitive mutant: possible role of myristic and oleic acids in tolerance.
AuthorsGutiérrez T, Learmonth RP, Nichols PD, Couperwhite I
JournalJ Chem Ecol
PubMed ID14682518
'A Gram positive bacterium of the genus Rhodococcus was isolated from a contaminated site in Sydney, Australia, for its ability to tolerate and degrade high concentrations of benzene. To identify fatty acids that may impart this Rhodococcus sp. with tolerance to toxic solvents, a benzene-sensitive strain, labeled M2b, was isolated ... More
Interactions of Laurdan with phosphatidylcholine liposomes: a high pressure FTIR study.
AuthorsChong PL, Wong PT
JournalBiochim Biophys Acta
PubMed ID8323945
'The interactions of 6-lauroyl-2-dimethylaminonaphthalene (Laurdan) with L-alpha-dimyristoylphosphatidylcholine (DMPC) have been studied isothermally at 28 degrees C by Fourier-transform infrared spectroscopy (FTIR) at two pH values (6.8 and 3.0) and over the pressure range of 0.001-25 kbar. The results obtained with Laurdan are compared with those previously obtained with 6-propionyl-2-dimethylaminonaphthalene (Prodan) ... More
Lipid rafts reconstituted in model membranes.
AuthorsDietrich C, Bagatolli LA, Volovyk ZN, Thompson NL, Levi M, Jacobson K, Gratton E
JournalBiophys J
PubMed ID11222302
'One key tenet of the raft hypothesis is that the formation of glycosphingolipid- and cholesterol-rich lipid domains can be driven solely by characteristic lipid-lipid interactions, suggesting that rafts ought to form in model membranes composed of appropriate lipids. In fact, domains with raft-like properties were found to coexist with fluid ... More
Fluorescence properties of Laurdan in cochleate phases.
AuthorsRamani K, Balasubramanian SV
JournalBiochim Biophys Acta
PubMed ID14643935
'Cochleates are lipid-based delivery system that have found application in drug and gene delivery. They are precipitates, formed as a result of interaction between cations (e.g. Ca2+) and negatively charged phospholipids such as phosphatidylserine (PS). In the present study, we investigated the utility of fluorescent probe Laurdan (6-dodecanoyl-2-dimethylamino naphthalene) to ... More
Fluorescence generalized polarization of cell membranes: a two-photon scanning microscopy approach.
AuthorsYu W, So PT, French T, Gratton E
JournalBiophys J
PubMed ID8789081
'We use the lipophilic fluorescence probe Laurdan to study cell membranes. The generalized polarization (GP) of Laurdan-labeled cells contains useful information about membrane fluidity and polarity. A high GP is usually associated with low fluidity, low polarity, or high cholesterol content of the membranes, and a low GP is the ... More
Prodan as a membrane surface fluorescence probe: partitioning between water and phospholipid phases.
AuthorsKrasnowska EK, Gratton E, Parasassi T
JournalBiophys J
PubMed ID9545057
'Fluorescence spectral features of 6-propionyl-2-dimethylaminonaphthalene (Prodan) in phospholipid vesicles of different phase states are investigated. Like the spectra of 6-lauroyl-2-dimethylaminonaphthalene (Laurdan), the steady-state excitation and emission spectra of Prodan are sensitive to the polarity of the environment, showing a relevant shift due to the dipolar relaxation phenomenon. Because of the ... More
Interaction between artificial membranes and enflurane, a general volatile anesthetic: DPPC-enflurane interaction.
AuthorsHauet N, Artzner F, Boucher F, Grabielle-Madelmont C, Cloutier I, Keller G, Lesieur P, Durand D, Paternostre M
JournalBiophys J
PubMed ID12719242
'The structural modifications of the dipalmitoylphosphatidylcholine (DPPC) organization induced by increasing concentration of the volatile anesthetic enflurane have been studied by differential scanning calorimetry, small-angle, and wide-angle x-ray scattering. The interaction of enflurane with DPPC depends on at least two factors: the enflurane-to-lipid concentration ratio and the initial organization of ... More
AuthorsGaus K, Le Lay S, Balasubramanian N, Schwartz MA
JournalJ Cell Biol
PubMed ID16943184
'The properties of cholesterol-dependent domains (lipid rafts) in cell membranes have been controversial. Because integrin-mediated cell adhesion and caveolin both regulate trafficking of raft components, we investigated the effects of adhesion and caveolin on membrane order. The fluorescent probe Laurdan and two-photon microscopy revealed that focal adhesions are highly ordered; ... More
Comparison of the effects of surface tension and osmotic pressure on the interfacial hydration of a fluid phospholipid bilayer.
'The effects of three so-called kosmotropic solutes, namely, betaine, sucrose, and choline chloride on 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine large unilamellar vesicles, were studied by measuring the generalized polarization (GP) for the fluorescence emission of the membrane partitioning probe Laurdan. The latter has been shown to be sensitive to the depth of water penetration ... More
The use of exogenous fluorescent probes for temperature measurements in single living cells.
AuthorsChapman CF, Liu Y, Sonek GJ, Tromberg BJ
JournalPhotochem Photobiol
PubMed ID8570701
'The fluorescent membrane probes 7-nitrobenz-2-oxa-1,3-diazol-4-yl (NBD) and 6-dodecanoyl-2-dimethylamino-naphthalene (laurdan) have been studied for use as optical thermometers in living cells. The thermal sensitivity of NBD is primarily a consequence of rapid, heat-induced electronic changes, which increase the observed fluorescence decay rate. As a result, fluorescence intensity and lifetime variations of ... More
Fluorescence studies of red blood cell membranes from individuals with Huntington's disease.
AuthorsSumbilla C, Lakowicz JR
JournalJ Neurochem
PubMed ID6210762
'Fluorescence spectroscopic methods were used to investigate and compare the properties of erythrocyte membranes from individuals with Huntington''s Disease (HD) and from normal individuals. Erythrocyte ghosts were labeled with four different fluorescent probes: 1,6-diphenylhexatriene (DPH); 6-lauroyl-2-(dimethylamino)-naphthalene (Laurdan); 2-(4-maleimide anilino)-naphthalene-6-sulfonic acid (MIANS) and 5-(iodoacetamidoethyl)aminoaphthalene-1-sulfonic acid (IAEDANS). DPH is sensitive to the ... More
Membrane binding of phospholipases C-beta 1 and C-beta 2 is independent of phosphatidylinositol 4,5-bisphosphate and the alpha and beta gamma subunits of G proteins.
AuthorsRunnels LW, Jenco J, Morris A, Scarlata S
JournalBiochemistry
PubMed ID8988021
'We have measured the membrane binding affinities of purified phosphatidylinositol-specific phospholipases C-beta 1 and C-beta 2 to membranes of varying lipid composition using fluorescence methods. Our studies show that these proteins bind with affinities of 10(-5)-10(-4) M, with a small dependence on lipid type. Binding was relatively insensitive to the ... More
Fluorescence spectroscopic studies of Huntington fibroblast membranes.
AuthorsLakowicz JR, Sheppard JR
JournalAm J Hum Genet
PubMed ID6452057
'Using fluorescence spectroscopic methods, we compared the membrane properties of intact fibroblasts from both normal subjects and patients with Huntington disease (HD). Cells were stained with various fluorophores, including 1-anilino-8-naphthalene sulfonic acid (ANS), 2-toluidinyl-6-naphthalene sulfonic acid (TNS), 1,6-diphenyl-1,3,5-hexatriene (DPH), and 6-lauroyl-2-(dimethylamino)-naphthalene (LAURDAN). Using these labeled cells, we measured fluorescence yields ... More
Membrane binding and self-association of alpha-synucleins.
AuthorsNarayanan V, Scarlata S
JournalBiochemistry
PubMed ID11502187
'Although its function is unknown, alpha-synuclein is widely distributed in neural tissue and is the major component in the pathological aggregates found in patients with Parkinson''s disease, Alzheimer''s disease, Down''s syndrome, and multiple system atrophy. In this report, we have quantified the binding alpha-synucleins to lipid membranes. In contrast to ... More
Different modulation of phospholipase A2 activity by saturated and monounsaturated N-acylethanolamines.
AuthorsZolese G, Wozniak M, Mariani P, Saturni L, Bertoli E, Ambrosini A
JournalJ Lipid Res
PubMed ID12562826
'The physiological functions of N-acylethanolamines (NAEs) are poorly understood, although many functions were suggested for these naturally occurring membrane components of plants and animals. The binding with cannabinoid receptors CB1 and CB2 was demonstrated for some NAEs, such as anandamide. However, the chemical nature of these molecules suggests that some ... More
On the importance of anandamide structural features for its interactions with DPPC bilayers: effects on PLA2 activity.
AuthorsAmbrosi S, Ragni L, Ambrosini A, Paccamiccio L, Mariani P, Fiorini R, Bertoli E, Zolese G
JournalJ Lipid Res
PubMed ID15961786
'The acylethanolamide anandamide (AEA) occurs in a variety of mammalian tissues and, as a result of its action on cannabinoid receptors, exhibits several cannabimimetic activities. Moreover, some of its effects are mediated through interaction with an ion channel-type vanilloid receptor. However, the chemical features of AEA suggest that some of ... More
Phase fluctuation in phospholipid membranes revealed by Laurdan fluorescence.
AuthorsParasassi T, De Stasio G, d'Ubaldo A, Gratton E
JournalBiophys J
PubMed ID2393703
'The organization of lipids surrounding membrane proteins can influence their properties. We have used 6-dodecanoyl-2-dimethylaminonaphthalene (Laurdan) to study phase coexistence and phase interconversion in membrane model systems. The fluorescence properties of Laurdan provide a unique possibility to study lipid domains because of the different excitation and emission spectra of this ... More
Two-photon fluorescence microscopy of laurdan generalized polarization domains in model and natural membranes.
AuthorsParasassi T, Gratton E, Yu WM, Wilson P, Levi M
JournalBiophys J
PubMed ID9168019
'Two-photon excitation microscopy shows coexisting regions of different generalized polarization (GP) in phospholipid vesicles, in red blood cells, in a renal tubular cell line, and in purified renal brushborder and basolateral membranes labeled with the fluorescent probe laurdan. The GP function measures the relative water content of the membrane. In ... More
Plasma membrane polarization during mating in yeast cells.
AuthorsProszynski TJ, Klemm R, Bagnat M, Gaus K, Simons K
JournalJ Cell Biol
PubMed ID16769822
'The yeast mating cell provides a simple paradigm for analyzing mechanisms underlying the generation of surface polarity. Endocytic recycling and slow diffusion on the plasma membrane were shown to facilitate polarized surface distribution of Snc1p (Valdez-Taubas, J., and H.R. Pelham. 2003. Curr. Biol. 13:1636-1640). Here, we found that polarization of ... More
Unique effects of different fatty acid species on the physical properties of the torpedo acetylcholine receptor membrane.
AuthorsAntollini SS, Barrantes FJ
JournalJ Biol Chem
PubMed ID11682474
'To study the effects produced by free fatty acids (FFA) on the biophysical properties of Torpedo marmorata nicotinic acetylcholine receptor-rich native membranes and to investigate the topology of their binding site(s), fluorescence measurements were carried out using the fluorescent probe Laurdan (6-dodecanoyl-2-(dimethylamino) naphthalene) and ADIFAB, an Acrylodan-derivatized intestinal fatty acid-binding ... More
Time-gated total internal reflection fluorescence spectroscopy (TG-TIRFS): application to the membrane marker laurdan.
AuthorsSchneckenburger H, Stock K, Strauss WS, Eickholz J, Sailer R
JournalJ Microsc
PubMed ID12839548
'A novel setup for total internal reflection fluorescence microscopy with spectral and temporal (nanosecond) resolution was used to measure the emission spectra of the membrane marker laurdan either selectively within the plasma membrane or in whole living cells, depending on the incident angle of the excitation light. With increasing temperature, ... More
Mechanisms by which intracellular calcium induces susceptibility to secretory phospholipase A2 in human erythrocytes.
AuthorsSmith SK, Farnbach AR, Harris FM, Hawes AC, Jackson LR, Judd AM, Vest RS, Sanchez S, Bell JD
JournalJ Biol Chem
PubMed ID11294854
'Exposure of human erythrocytes to the calcium ionophore ionomycin rendered them susceptible to the action of secretory phospholipase A(2) (sPLA(2)). Analysis of erythrocyte phospholipid metabolism by thin-layer chromatography revealed significant hydrolysis of both phosphatidylcholine and phosphatidylethanolamine during incubation with ionomycin and sPLA(2). Several possible mechanisms for the effect of ionomycin ... More
Agrin elicits membrane lipid condensation at sites of acetylcholine receptor clusters in C2C12 myotubes.
AuthorsStetzkowski-Marden F, Gaus K, Recouvreur M, Cartaud A, Cartaud J
JournalJ Lipid Res
PubMed ID16816402
'The formation of the neuromuscular junction is characterized by the progressive accumulation of nicotinic acetylcholine receptors (AChRs) in the postsynaptic membrane facing the nerve terminal, induced predominantly through the agrin/muscle-specific kinase (MuSK) signaling cascade. However, the cellular mechanisms linking MuSK activation to AChR clustering are still poorly understood. Here, we ... More
Relationships between bilayer structure and phospholipase A2 activity: interactions among temperature, diacylglycerol, lysolecithin, palmitic acid, and dipalmitoylphosphatidylcholine.
AuthorsBell JD, Burnside M, Owen JA, Royall ML, Baker ML
JournalBiochemistry
PubMed ID8664287
'Bilayers composed of phosphatidylcholine initially resist catalysis by phospholipase A2. However, after a latency period, they become susceptible when sufficient reaction products (lysolecithin and fatty acid) accumulate in the membrane. Temperatures near the main bilayer phase transition and saturated long-chain diacylglycerol in the bilayer modulate the effectiveness of the reaction ... More
Cholesterol modifies water concentration and dynamics in phospholipid bilayers: a fluorescence study using Laurdan probe.
AuthorsParasassi T, Di Stefano M, Loiero M, Ravagnan G, Gratton E
JournalBiophys J
PubMed ID8011908
'The effect of cholesterol on the gel, the liquid-crystalline, and mixed phospholipid phases has been studied using the fluorescence properties of 2-dimethylamino-6-lauroylnaphthalene (Laurdan). Laurdan sensitivity to the polarity and to the dynamics of its environment reveals that cholesterol affects phospholipid bilayers in the gel phase by expelling water and by ... More
Definition of the specific roles of lysolecithin and palmitic acid in altering the susceptibility of dipalmitoylphosphatidylcholine bilayers to phospholipase A2.
AuthorsHenshaw JB, Olsen CA, Farnbach AR, Nielson KH, Bell JD
JournalBiochemistry
PubMed ID9692961
'Bilayers composed of phosphatidylcholine initially resist catalysis by phospholipase A2. However, after a latency period, they become susceptible when sufficient reaction products (lysolecithin and fatty acid) accumulate in the membrane. Temperature near the main bilayer phase transition and calcium concentration modulate the effectiveness of the reaction products. The purpose of ... More
Acute and chronic changes in cholesterol modulate Na-Pi cotransport activity in OK cells.
AuthorsBreusegem SY, Halaihel N, Inoue M, Zajicek H, Lederer E, Barry NP, Sorribas V, Levi M
JournalAm J Physiol Renal Physiol
PubMed ID15769937
'We previously showed an inverse correlation between membrane cholesterol content and Na-P(i) cotransport activity during the aging process and adaptation to alterations in dietary P(i) in the rat (Levi M, Jameson DM, and van der Meer BW. Am J Physiol Renal Fluid Electrolyte Physiol 256: F85-F94, 1989). The purpose of ... More
Influence of cholesterol on phospholipid bilayers phase domains as detected by Laurdan fluorescence.
AuthorsParasassi T, Di Stefano M, Loiero M, Ravagnan G, Gratton E
JournalBiophys J
PubMed ID8130331
'Coexisting gel and liquid-crystalline phospholipid phase domains can be observed in synthetic phospholipid vesicles during the transition from one phase to the other and, in vesicles of mixed phospholipids, at intermediate temperatures between the transitions of the different phospholipids. The presence of cholesterol perturbs the dynamic properties of both phases ... More
Lipid-protein interactions in rat renal subcellular membranes: a biophysical and biochemical study.
AuthorsD'Antuono C, Fernández-Tomé MC, Sterin-Speziale N, Bernik DL
JournalArch Biochem Biophys
PubMed ID11051095
'The phase behavior of plasma membrane (PM), endoplasmic reticulum (ER), and nuclear membranes (NM) isolated from adult rat papillary cells was studied using the molecular probe Laurdan. The steady-state fluorescence data analysis was correlated with the lipid composition obtained by biochemical assays. The comparison between intact membranes and protein-free reconstituted ... More
Perturbation of the chain melting transition of DPPC by galactose, agarose and Laurdan as determined by differential scanning calorimetry.
AuthorsAbrams SB, Yager P
JournalBiochim Biophys Acta
PubMed ID8443219
'Differential scanning calorimetry was used to determine the effects of agarose hydrogel, galactose and the fluorophore Laurdan on the thermal behavior of multilamellar liposomes of DPPC. Although the effect of agarose on the phase transition was found to be negligible at low concentrations (< or = 2.5%), higher concentrations result ... More
Physicochemical and functional modifications induced by obesity on human erythrocyte membranes.
AuthorsFaloia E, Garrapa GG, Martarelli D, Camilloni MA, Lucarelli G, Staffolani R, Mantero F, Curatola G, Mazzanti L
JournalEur J Clin Invest
PubMed ID10354200
'BACKGROUND: Na+,K(+)-ATPase activity was evaluated in relation to membrane composition and molecular organization in erythrocyte membranes from obese patients by the amphyphylic molecule 6-dodecanoyl-2-dimethylamino-naphthalene (Laurdan). Its possible relationship with fat distribution and hyperinsulinaemia was also investigated. DESIGN: Subjects were 10 obese men (OM), 12 women with subcutaneous obesity (FSO), 10 ... More
Myelin basic protein-dependent plasma membrane reorganization in the formation of myelin.
AuthorsFitzner D, Schneider A, Kippert A, Möbius W, Willig KI, Hell SW, Bunt G, Gaus K, Simons M
JournalEMBO J
PubMed ID17036049
'During vertebrate development, oligodendrocytes wrap their plasma membrane around axons to produce myelin, a specialized membrane highly enriched in galactosylceramide (GalC) and cholesterol. Here, we studied the formation of myelin membrane sheets in a neuron-glia co-culture system. We applied different microscopy techniques to visualize lipid packing and dynamics in the ... More
Al(3+)-mediated changes on membrane fluidity affects the activity of PI-PLC but not of PLC.
AuthorsVerstraeten SV, Villaverde MS, Oteiza PI
JournalChem Phys Lipids
PubMed ID12598047
'We investigated whether Al(3+)-mediated changes in membrane fluidity can affect the activity of prokaryotic enzymes phospholipase C (PLC) and phospholipase C-phosphatidyl inositol specific (PI-PLC) in liposomes of phosphatidyl choline (PC), PC:phosphatidyl inositol (PI), or PC and polyphosphoinositides (PPI). Al(3+) (10-100 microM) promoted membrane rigidification, evaluated with the probes 1,6-diphenyl-1,3,5-hexatriene and ... More
Flexible loop of beta 2-glycoprotein I domain V specifically interacts with hydrophobic ligands.
AuthorsHong DP, Hagihara Y, Kato H, Goto Y
JournalBiochemistry
PubMed ID11434778
'Beta2-glycoprotein I (beta2-GPI), which consists of four complement control protein modules and a distinctly folded fifth C-terminal domain, is an essential cofactor for the binding to phospholipids of anti-cardiolipin antibodies, isolated from patients with anti-phospholipid antibody syndrome, and its fifth domain has attracted attention as a specific phospholipid-binding site. We ... More
Bimodal distribution and fluorescence response of environment-sensitive probes in lipid bilayers.
AuthorsKlymchenko AS, Duportail G, Demchenko AP, Mély Y
JournalBiophys J
PubMed ID15111409
'A remarkable heterogeneity is often observed in the spectroscopic properties of environment-sensitive fluorescence probes in phospholipid bilayers. To explain its origin, we provided a detailed investigation of the fluorescence excitation and emission spectra of 4''-dimethylamino-3-hydroxyflavone (probe F) in bilayer vesicles with the variations of fatty acid composition, polar heads, temperature, ... More
Osmotic response in Lactobacillus casei ATCC 393: biochemical and biophysical characteristics of membrane.
AuthorsMachado MC, López CS, Heras H, Rivas EA
JournalArch Biochem Biophys
PubMed ID14725858
'The biochemical and biophysical properties of the membrane and some general characteristics of the response of Lactobacillus casei ATCC 393 (reclassified Lactobacillus zeae) to hyperosmotic conditions were studied. Under hypertonic conditions, the hydrophobicity and the bile salt sensitivity of the cultures were increased. The glycolipid AcylH3DG is only present in ... More
Synthesis and spectral properties of a hydrophobic fluorescent probe: 6-propionyl-2-(dimethylamino)naphthalene.
AuthorsWeber G, Farris FJ
JournalBiochemistry
PubMed ID465454
'Environmentally sensitive fluorescent probes involve two groups, an electron donor and an electron acceptor, attached to an aromatic ring system, and maximal effects may be expected when these groups are as far apart as feasible. The syntheisis, characterization, and spectroscopic properties of 6-propionyl-2-(dimethylamino)naphthalene (PRODAN), a compound that fulfills these conditions, ... More
Modulation and dynamics of phase properties in phospholipid mixtures detected by Laurdan fluorescence.
AuthorsParasassi T, Ravagnan G, Rusch RM, Gratton E
JournalPhotochem Photobiol
PubMed ID8475171
'Steady-state and dynamic fluorescence properties of 6-lauroyl-2-dimethylaminonaphthalene (Laurdan) have been used to ascertain the coexistence of separate phase domains and their dynamic properties in phospholipid vesicles composed of different mole ratios of dilauroyl- and dipalmitoyl-phosphatidylcholine (DLPC and DPPC, respectively). The recently introduced generalized polarization together with time-resolved emission spectra have ... More
Effect of genistein against copper-induced lipid peroxidation of human high density lipoproteins (HDL).
AuthorsFerretti G, Bacchetti T, Menanno F, Curatola G
JournalAtherosclerosis
PubMed ID14709357
'Several studies have demonstrated that the isoflavone genistein exerts a protective effect against lipid peroxidation of low density lipoproteins (LDL). Aim of our study was to investigate whether genistein protects high density lipoproteins (HDL), isolated from normolipemic subjects, against Cu(++)-induced lipid peroxidation. Our results demonstrated that genistein exerts an inhibitory ... More
Partition coefficient of a surfactant between aggregates and solution: application to the micelle-vesicle transition of egg phosphatidylcholine and octyl beta-D-glucopyranoside.
AuthorsPaternostre M, Meyer O, Grabielle-Madelmont C, Lesieur S, Ghanam M, Ollivon M
JournalBiophys J
PubMed ID8599654
'The mechanism of the solubilization of egg phosphatidylcholine containing 10% (M/M) of egg phosphatidic acid unilamellar vesicles by the nonionic detergent, octyl beta-D-glucopyranoside, has been investigated at both molecular and supramolecular levels by using fluorescence and turbidity measurements. In the lamellar region of the transition, the solubilization process has been ... More
Direct observation of lipid domains in free standing bilayers: from simple to complex lipid mixtures.
AuthorsBagatolli LA
JournalChem Phys Lipids
PubMed ID12598044
'The direct observation of temperature-dependent lipid phase equilibria, using two-photon excitation fluorescence microscopy on giant unilamellar vesicles (GUVs) composed of different lipid mixtures, provides novel information about the physical characteristics of lipid domain coexistence. Physical characteristics such as shape, size, and time evolution of different lipid domains are not directly ... More
A model for the interaction of 6-lauroyl-2-(N,N-dimethylamino)naphthalene with lipid environments: implications for spectral properties.
AuthorsBagatolli LA, Parasassi T, Fidelio GD, Gratton E
JournalPhotochem Photobiol
PubMed ID10546552
'Although 6-lauroyl-2-(N,N-dimethylamino)naphthalene (LAURDAN) is now widely used as a probe for lipid systems, most studies focus on the effect of the lipid environment on its emission properties but not on the excitation properties. The present study is intended to investigate the excitation properties of LAURDAN in diverse lipid environments. To ... More
Time-resolved fluorescence emission spectra of Laurdan in phospholipid vesicles by multifrequency phase and modulation fluorometry.
AuthorsParasassi T, Conti F, Gratton E
JournalCell Mol Biol
PubMed ID3753899
Demonstration of nanosecond dipolar relaxation in biopolymers by inversion of apparent fluorescence phase shift and demodulation lifetimes.
AuthorsLakowicz JR, Cherek H, Bevan DR
JournalJ Biol Chem
PubMed ID7372582
Fluorophores in a polar medium: time dependence of emission spectra detected by multifrequency phase and modulation fluorometry.
AuthorsParasassi T, Conti F, Gratton E
JournalCell Mol Biol
PubMed ID3948209
Inclusion complexes of ploy-beta-cyclodextrin: a model for pressure effects upon ligand-protein complexes.
AuthorsTorgerson PM, Drickamer HG, Weber G
JournalBiochemistry
PubMed ID465455
Fluorescence analysis of lipoprotein peroxidation.
AuthorsDousset N, Ferretti G, Taus M, Valdiguiè P, Curatola G
JournalMethods Enzymol
PubMed ID8015481
Giant vesicles, Laurdan, and two-photon fluorescence microscopy: evidence of lipid lateral separation in bilayers.
AuthorsBagatolli LA, Sanchez SA, Hazlett T, Gratton E
JournalMethods Enzymol
PubMed ID12622164
Abstract
Spectroscopic techniques in the study of membrane solubilization, reconstitution and permeabilization by detergents.
AuthorsGoñi FM, Alonso A
JournalBiochim Biophys Acta
PubMed ID11090818
This review focuses on the use of spectroscopic techniques for the study of membrane solubilization, reconstitution, and permeabilization by detergents. Turbidity and light scattering, visible and infrared spectroscopic methods, fluorescence, nuclear magnetic resonance, electron spin resonance and X-ray diffraction are examined from the point of view of their applicability to ... More
Monitoring biophysical properties of lipid membranes by environment-sensitive fluorescent probes.
AuthorsDemchenko AP, Mély Y, Duportail G, Klymchenko AS,
JournalBiophys J
PubMed ID19413953
We review the main trends in the development of fluorescence probes to obtain information about the structure, dynamics, and interactions in biomembranes. These probes are efficient for studying the microscopic analogs of viscosity, polarity, and hydration, as well as the molecular order, environment relaxation, and electrostatic potentials at the sites ... More
The pleckstrin homology domain of phospholipase C-beta(2) links the binding of gbetagamma to activation of the catalytic core.
AuthorsWang T, Dowal L, El-Maghrabi MR, Rebecchi M, Scarlata S
JournalJ Biol Chem
PubMed ID10713048
Pleckstrin homology (PH) domains are membrane tethering devices found in many signal transducing proteins. These domains also couple to the betagamma subunits of GTP binding proteins (G proteins), but whether this association transmits allosteric information to the catalytic core is unclear. To address this question, we constructed protein chimeras in ... More
Use of Laurdan fluorescence in studying plasma membrane organization of polymorphonuclear leukocytes during the respiratory burst.
AuthorsFiorini R, Curatola G, Kantar A, Giorgi PL, Gratton E
JournalPhotochem Photobiol
PubMed ID8475176
The changes in plasma membrane polarity of polymorphonuclear leukocytes (PMN) during the activation of the respiratory burst were investigated by measuring the steady-state fluorescence emission spectra of 2-dimethylamino(6-lauroyl) naphthalene (Laurdan), which is known to be incorporated at the hydrophobic-hydrophilic interface of the bilayer, displaying spectral sensitivity to the polarity of ... More
Lipid phases in renal brush border membranes revealed by Laurdan fluorescence.
AuthorsLevi M, Wilson PV, Cooper OJ, Gratton E
JournalPhotochem Photobiol
PubMed ID8475174
Steady-state fluorescence properties of 6-dodecanoyl-2-dimethylaminonapththalene (Laurdan) have been used to determine the coexistence of separate lipid-phase domains in apical brush border membrane vesicles isolated from the rat renal cortex. The temperature dependence of generalized polarization has been utilized to quantitate the lipid phases. Finally, the effect of cholesterol enrichment on ... More
A study of quercetin effects on phospholipid membranes containing cholesterol using Laurdan fluorescence.
AuthorsIonescu D, Ganea C,
JournalEur Biophys J
PubMed ID22302013
Quercetin (QCT) is an important bioactive natural compound found in numerous edible plants. Since the lipid bilayer represents an essential compound of the cell membrane, QCT's direct interaction with this structure is of great interest. Therefore, we proposed to study the effects of QCT on DMPC liposomes containing cholesterol (Chol), ... More
Limited cholesterol depletion causes aggregation of plasma membrane lipid rafts inducing T cell activation.
AuthorsMahammad S, Dinic J, Adler J, Parmryd I,
JournalBiochim Biophys Acta
PubMed ID20153839
Acute cholesterol depletion is generally associated with decreased or abolished T cell signalling but it can also cause T cell activation. This anomaly has been addressed in Jurkat T cells using progressive cholesterol depletion with methyl-beta-cyclodextrin (MBCD). At depletion levels higher than 50% there is substantial cell death, which explains ... More
Laurdan and di-4-ANEPPDHQ do not respond to membrane-inserted peptides and are good probes for lipid packing.
AuthorsDinic J, Biverståhl H, Mäler L, Parmryd I,
JournalBiochim Biophys Acta
PubMed ID20937246
Laurdan and di-4-ANEPPDHQ are used as probes for membrane order, with a blue shift in emission for membranes in liquid-ordered (lo) phase relative to membranes in liquid-disordered (ld) phase. Their use as membrane order probes requires that their spectral shifts are unaffected by membrane proteins, which we have examined by ... More
Clustering and lateral concentration of raft lipids by the MAL protein.
AuthorsMagal LG, Yaffe Y, Shepshelovich J, Aranda JF, de Marco Mdel C, Gaus K, Alonso MA, Hirschberg K,
JournalMol Biol Cell
PubMed ID19553470
MAL, a compact hydrophobic, four-transmembrane-domain apical protein that copurifies with detergent-resistant membranes is obligatory for the machinery that sorts glycophosphatidylinositol (GPI)-anchored proteins and others to the apical membrane in epithelia. The mechanism of MAL function in lipid-raft-mediated apical sorting is unknown. We report that MAL clusters formed by two independent ... More
Relationship between membrane physical properties and secretory phospholipase A2 hydrolysis kinetics in S49 cells during ionophore-induced apoptosis.
AuthorsBailey RW, Olson ED, Vu MP, Brueseke TJ, Robertson L, Christensen RE, Parker KH, Judd AM, Bell JD,
JournalBiophys J
PubMed ID17545239
During apoptosis, changes occur in lymphocyte membranes that render them susceptible to hydrolysis by secretory phospholipase A(2) (sPLA(2)). To study the relevant mechanisms, a simplified model of apoptosis using a calcium ionophore was applied. Kinetic and flow cytometry experiments provided key observations regarding ionophore treatment: the initial rate of hydrolysis ... More
FAPP2, cilium formation, and compartmentalization of the apical membrane in polarized Madin-Darby canine kidney (MDCK) cells.
We have analyzed the role of the phosphatidylinositol-4-phosphate adaptor protein-2 (FAPP2), a component of the apical transport machinery, in cilium formation in polarized Madin-Darby canine kidney (MDCK) cells. We show that ciliogenesis is defective in FAPP2 knockdown cells. Furthermore, by using fluorescence recovery after photobleaching studies of domain connectivity and ... More
Probing the structure of diacetylenic phospholipid tubules with fluorescent lipophiles.
AuthorsPlant AL, Benson DM, Trusty GL
JournalBiophys J
PubMed ID2340344
Novel lipid structures called tubules can be prepared from diacetylenic phospholipids. We have prepared fluorescent tubules from mixtures of 1,2-bis(10,12-tricosadiynoyl)-sn-glycero-3-phosphatidylcholine and 1 mol% fluorescent lipophiles to study the characteristics of the tubule lipid matrix. We have found that once formed, tubules do not incorporate lipophiles from the aqueous phase into ... More
Laurdan fluorescence spectroscopy reveals a single liquid-crystalline lipid phase and lack of thermotropic phase transitions in the plasma membrane of living human sperm.
AuthorsPalleschi S, Silvestroni L
JournalBiochim Biophys Acta
PubMed ID8603087
Membrane lipid phase(s), phase coexistence, and thermotropic phase transitions have been investigated in viable human spermatozoa using Laurdan fluorescence spectroscopy. Generalized polarization (GP) values derived from Laurdan excitation and emission spectra confirm that the sperm plasma membrane is a low polar, highly rigid (liquid-ordered) structure, and give evidence that, in ... More
Visualizing lipid structure and raft domains in living cells with two-photon microscopy.
AuthorsGaus K, Gratton E, Kable EP, Jones AS, Gelissen I, Kritharides L, Jessup W
JournalProc Natl Acad Sci U S A
PubMed ID14673117
The lateral organization of cellular membranes is formed by the clustering of specific lipids, such as cholesterol and sphingolipids, into highly condensed domains (termed lipid rafts). Hence such domains are distinct from the remaining membrane by their lipid structure (liquid-ordered vs. -disordered domains). Here, we directly visualize membrane lipid structure ... More
Membrane/water partition of oligo(ethylene oxide) dodecyl ethers and its relevance for solubilization.
AuthorsHeerklotz H, Binder H, Lantzsch G, Klose G
JournalBiochim Biophys Acta
PubMed ID7841174
Mixed aqueous dispersions containing palmitoyloleoylphosphatidylcholine and oligo(ethylene oxide) dodecyl ethers C12EOn with n = 2-8 have been investigated. The aggregates composition has been determined as a function of the aqueous detergent concentration using Laurdan fluorescence spectroscopy. The partition of the detergent between the membranes and the aqueous phase has been ... More
Peroxyl radicals promoted changes in water permeability through gramicidin channels in DPPC and lecithin-PC vesicles.
AuthorsSoto MA, Sotomayor CP, Lissi EA
JournalChem Phys Lipids
PubMed ID12637166
Gramicidin incorporation to DPPC or lecithin-PC large unilamellar vesicles (LUVs) leads to pore formation that, under hyper-osmotic conditions, produces a noticeable increase in the rate of trans-membrane water flow. This pore formation is more efficient in the more fluid lecithin-PC LUVs. Exposure of these vesicles to peroxyl radicals generated in ... More
Cutting edge: optical microspectrophotometry supports the existence of gel phase lipid rafts at the lamellipodium of neutrophils: apparent role in calcium signaling.
AuthorsKindzelskii AL, Sitrin RG, Petty HR
JournalJ Immunol
PubMed ID15067042
Although much progress has been made in elucidating the biochemical properties of lipid rafts, there has been less success in identifying these structures within living cell membranes, which has led to some concern regarding their existence. One difficulty in analyzing lipid rafts using optical microscopy is their small size. We ... More
Condensation of the plasma membrane at the site of T lymphocyte activation.
AuthorsGaus K, Chklovskaia E, Fazekas de St Groth B, Jessup W, Harder T
JournalJ Cell Biol
PubMed ID16203859
After activation, T lymphocytes restructure their cell surface to form membrane domains at T cell receptor (TCR)-signaling foci and immunological synapses (ISs). To address whether these rearrangements involve alteration in the structure of the plasma membrane bilayer, we used the fluorescent probe Laurdan to visualize its lipid order. We observed ... More
Quantitation of lipid phases in phospholipid vesicles by the generalized polarization of Laurdan fluorescence.
AuthorsParasassi T, De Stasio G, Ravagnan G, Rusch RM, Gratton E
JournalBiophys J
PubMed ID1883937
The sensitivity of Laurdan (6-dodecanoyl-2-dimethylaminonaphthalene) excitation and emission spectra to the physical state of the membrane arises from dipolar relaxation processes in the membrane region surrounding the Laurdan molecule. Experiments performed using phospholipid vesicles composed of phospholipids with different polar head groups show that this part of the molecule is ... More
Idiopathic infertility: susceptibility of spermatozoa to in-vitro capacitation, in the presence and the absence of palmitylethanolamide (a homologue of anandamide), is strongly correlated with membrane polarity studied by Laurdan fluorescence.
AuthorsAmbrosini A, Zolese G, Wozniak M, Genga D, Boscaro M, Mantero F, Balercia G
JournalMol Hum Reprod
PubMed ID12802044
Capacitation is a widely investigated process, which induces sperm plasma membrane changes resulting in its increased affinity for the zona pellucida. The fluorescent probe Laurdan, localized only within the plasma membrane of spermatozoa, is particularly useful to evaluate bilayer polarity in this part of the cell. According to a previous ... More
Two photon fluorescence microscopy of coexisting lipid domains in giant unilamellar vesicles of binary phospholipid mixtures.
AuthorsBagatolli LA, Gratton E
JournalBiophys J
PubMed ID10620293
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) ... More
A correlation between lipid domain shape and binary phospholipid mixture composition in free standing bilayers: A two-photon fluorescence microscopy study.
AuthorsBagatolli LA, Gratton E
JournalBiophys J
PubMed ID10866969
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 ... More
Fluorescence study on rat epithelial cells and liposomes exposed to aromatic nitroxides.
AuthorsGabbianelli R, Falcioni G, Lupidi G, Greci L, Damiani E
JournalComp Biochem Physiol C Toxicol Pharmacol
PubMed ID15228954
This study was performed to evaluate the effects, if any, of aromatic nitroxides, namely, indolinic nitroxides, on membrane fluidity of rat epithelial cells using steady-state fluorescence. These nitroxides are being increasingly considered as new and versatile compounds to reduce oxidative stress in biological systems. Hence, the results obtained in this ... More
Fluorescence studies of lipid regular distribution in membranes.
AuthorsChong PL, Sugár IP
JournalChem Phys Lipids
PubMed ID12093540
This article reviews the use of fluorescent lipids and free probes in the studies of lipid regular distribution in model membranes. The first part of this article summarizes the evidence and physical properties for lipid regular distribution in pyrene-labeled phosphatidylcholine (PC)/unlabeled PC binary mixtures as revealed by the fluorescence of ... More
Loss of apoB-100 secondary structure and conformation in hydroperoxide rich, electronegative LDL(-).
AuthorsParasassi T, Bittolo-Bon G, Brunelli R, Cazzolato G, Krasnowska EK, Mei G, Sevanian A, Ursini F
JournalFree Radic Biol Med
PubMed ID11425493
A subpopulation of low-density lipoproteins (LDL) is present in human plasma that contains lipid hydroperoxides and is more negatively charged (LDL(-)) than normal native LDL. By circular dichroism and tryptophan lifetime measurements we found that apoB-100 secondary structure is markedly decreased and its conformation is severely altered in LDL(-). The ... More
Hexagonal phase forming propensity detected in phospholipid bilayers with fluorescent probes.
AuthorsEpand RM, Leon BT
JournalBiochemistry
PubMed ID1737012
The fluorescence emission spectrum of N epsilon-dansyl-L-Lys undergoes a marked blue shift when incorporated from aqueous solution into phospholipid bilayers. This shift is greater for membranes composed of dipalmitoleoylphosphatidylcholine than for membranes of dipalmitoleoylphosphatidylethanolamine. With the latter but not the former lipid, the fluorescence emission from N epsilon-dansyl-L-Lys is markedly ... More
Surface properties of cholesterol-containing membranes detected by Prodan fluorescence.
AuthorsKrasnowska EK, Bagatolli LA, Gratton E, Parasassi T
JournalBiochim Biophys Acta
PubMed ID11286976
The fluorescent membrane probe 6-propionyl-2-dimethylaminonaphthalene (Prodan) displays a high sensitivity to the polarity and packing properties of lipid membrane. Contrary to 6-lauroyl-2-dimethylaminonaphthalene (Laurdan), Prodan can also monitor the properties of the membrane surface, i.e., the polar-head pretransition. In bilayers composed of coexisting gel and liquid-crystalline phases, Prodan shows a preferential ... More
Partition of the organochlorine insecticide lindane into the human sperm surface induces membrane depolarization and Ca2+ influx.
AuthorsSilvestroni L, Fiorini R, Palleschi S
JournalBiochem J
PubMed ID9032455
The effects of the insecticide lindane (the gamma-isomer of 1,2,3,4,5,6-hexachlorocyclohexane) on membrane potential, cytosolic free Ca2+ concentration ([Ca2+]i) and surface biophysical properties were studied in human spermatozoa. The insecticide induces rapid, transient and reproducible membrane depolarization and opening of voltage-dependent Ca2+ channels leading to an increase in [Ca2+]i. In contrast ... More
Effect of sodium dodecyl sulfate and palmitic acid on the equilibrium unfolding of bovine beta-lactoglobulin.
AuthorsCreamer LK
JournalBiochemistry
PubMed ID7766627
The unfolding of bovine beta-lactoglobulin, a small globular protein that unfolds reversibly at low pH in the presence of urea or guanidine hydrochloride, has been studied at pH 6.72 in phosphate buffer at 21 degrees C. The midpoint urea concentration for the loss of CD intensity at 220 nm, loss ... More
Membrane aging during cell growth ascertained by Laurdan generalized polarization.
AuthorsParasassi T, Di Stefano M, Ravagnan G, Sapora O, Gratton E
JournalExp Cell Res
PubMed ID1397095
The sensitivity of the fluorescent probe Laurdan to the phase state of lipids has been utilized to detect modifications in the composition and physical state of cell membranes during cell growth. In phospholipid vesicles, the Laurdan emission spectrum shows a 50-nm red shift by passing from the gel to the ... More
Absence of lipid gel-phase domains in seven mammalian cell lines and in four primary cell types.
AuthorsParasassi T, Loiero M, Raimondi M, Ravagnan G, Gratton E
JournalBiochim Biophys Acta
PubMed ID8274484
Fluorescence properties of 6-lauroyl-2-dimethylaminonaphthalene (Laurdan) are used to explore gel and liquid-crystalline phase domains coexistence in membranes of various cell types and in erythrocyte ghosts. Experiments and simulations were performed using liposomes composed of equimolar gel and liquid-crystalline phases in the absence and in the presence of 30 mol% cholesterol. ... More
Spectral properties of environmentally sensitive probes associated with horseradish peroxidase.
AuthorsLasagna M, Vargas V, Jameson DM, Brunet JE
JournalBiochemistry
PubMed ID8547280
The environmentally sensitive fluorescent probes 6-propionyl-2-(N,N-dimethylamino)naphthalene (PRODAN) and 2'-(N,N-dimethylamino)-6-naphthoyl-4-trans-cyclohexanioc acid (DANCA) form complexes with the heme binding site of apohorseradish peroxidase. The dissociation constants of the PRODAN and DANCA complexes were determined from anisotropy titration data to be approximately 8.7 x 10(-5) and 3.3 x 10(-4) M, respectively. From comparison ... More
Enhancement of Agkistrodon piscivorus piscivorus venom phospholipase A2 activity toward phosphatidylcholine vesicles by lysolecithin and palmitic acid: studies with fluorescent probes of membrane structure.
AuthorsSheffield MJ, Baker BL, Li D, Owen NL, Baker ML, Bell JD
JournalBiochemistry
PubMed ID7794890
The activity of phospholipase A2 from snake venom to hydrolyze bilayers of phosphatidylcholines is greatly enhanced by the presence of the hydrolysis products, lysolecithin and fatty acid, in the bilayer. The fluorescence of several probes of membrane structure was used to monitor changes in bilayer physical properties during vesicle hydrolysis. ... More
Giant phospholipid vesicles: comparison among the whole lipid sample characteristics using different preparation methods: a two photon fluorescence microscopy study.
AuthorsBagatolli LA, Parasassi T, Gratton E
JournalChem Phys Lipids
PubMed ID10823462
Several methods for the preparation of giant unilamellar vesicles (GUVs) using synthetic phosphatidylcholine phospholipids were evaluated. We compared the physical characteristics--in terms of lamellarity and morphology--of the whole lipid sample for each different lipid preparation using the sectioning capability of the two-photon excitation fluorescence microscope. From the evaluation of the ... More
Laurdan properties in glycosphingolipid-phospholipid mixtures: a comparative fluorescence and calorimetric study.
AuthorsBagatolli LA, Maggio B, Aguilar F, Sotomayor CP, Fidelio GD
JournalBiochim Biophys Acta
PubMed ID9106485
Laurdan (6-dodecanoyl-2-dimethylamine-naphthalene) is a fluorescent membrane probe of recent characterization. It was shown that this probe discriminates between phase transitions, phase fluctuations and the coexistence of phase domains in phospholipid multilamellar aggregates. We measured the excitation and emission generalized polarization (GP(ex) and GP(em)) of Laurdan in aggregates of complex glycosphingolipids ... More
Phospholipid-cationic lipid interactions: influences on membrane and vesicle properties.
Liposomes composed of synthetic dialkyl cationic lipids and zwitterionic phospholipids such as dioleoylphosphatidylethanolamine have been studied extensively as vehicles for gene delivery, but the broader potentials of these cationic liposomes for drug delivery have not. An understanding of phospholipid-cationic lipid interactions is essential for rational development of this potential. We ... More
Divalent cations increase lipid order in erythrocytes and susceptibility to secretory phospholipase A2.
AuthorsVest RS, Gonzales LJ, Permann SA, Spencer E, Hansen LD, Judd AM, Bell JD
JournalBiophys J
PubMed ID15041664
Elevated concentrations of intracellular calcium in erythrocytes increase membrane order and susceptibility to secretory phospholipase A2. We hypothesize that calcium aids the formation of domains of ordered lipids within erythrocyte membranes by interacting directly with the inner leaflet of the cell membrane. The interface of these domains with regions of ... More
Phospholipid phase transitions in homogeneous nanometer scale bilayer discs.
AuthorsShaw AW, McLean MA, Sligar SG
JournalFEBS Lett
PubMed ID14706860
Nanoscale protein supported phospholipid bilayer discs, or Nanodiscs, were produced for the purpose of studying the phase transition behavior of the incorporated lipids. Nanodiscs and vesicles were prepared with two phospholipids, dipalmitoyl phosphatidylcholine and dimyristoyl phosphatidylcholine, and the phase transition of each was analyzed using laurdan fluorescence and differential scanning ... More
Interactions of thionin from Pyrularia pubera with dipalmitoylphosphatidylglycerol large unilamellar vesicles.
AuthorsHuang W, Vernon LP, Hansen LD, Bell JD
JournalBiochemistry
PubMed ID9062115
The peptide toxin thionin from Pyrularia pubera binds to dipalmitoylphosphatidylglycerol (DPPG) large unilamellar vesicles as shown by an increase in the intensity and blue-shift of the fluorescence emission spectrum of the single tryptophan residue of the protein. The magnitude of these fluorescence changes increased with temperature near the thermotropic phase ... More
Estradiol enhances the resistance of LDL to oxidation by stabilizing apoB-100 conformation.
AuthorsBrunelli R, Mei G, Krasnowska EK, Pierucci F, Zichella L, Ursini F, Parasassi T
JournalBiochemistry
PubMed ID11076531
Among different proposed mechanisms to account for the protection exerted by estrogens against cardiovascular diseases, the antioxidant effect has attracted considerable attention. We confirmed that 17-beta-estradiol (E2), when added to human LDL at a 6:1 ratio to apoB-100, markedly delays the phase of massive LDL lipid peroxidation induced by Cu(2+). ... More
Properties of palmitoyl phosphatidylcholine, sphingomyelin, and dihydrosphingomyelin bilayer membranes as reported by different fluorescent reporter molecules.
AuthorsNyholm T, Nylund M, Söderholm A, Slotte JP
JournalBiophys J
PubMed ID12547780
The properties of vesicle membranes prepared from 16:0-SM, 16:0-DHSM, or DPPC were characterized using steady-state and time-resolved fluorescence spectroscopy and different fluorescent reporter molecules. The acyl-chain region was probed using free and phospholipid-bound 1,6-diphenyl-1,3,5-hexatriene. 16:0-DHSM was found to be the more ordered than both DPPC and 16:0-SM 5 degrees C ... More
Phototoxic effect of fluoroquinolones on two human cell lines.
AuthorsTrisciuoglio D, Krasnowska E, Maggi A, Pozzi R, Parasassi T, Sapora O
JournalToxicol In Vitro
PubMed ID12110285
Photosensitization induced by the fluoroquinolone ofloxacin (OFLX) has been studied using two human cell lines, HL60 and K562, two UV wavelengths, 290 and 330 nm, and two different exposure protocols, acute and protracted. The examined endpoints are the cellular lethality and recovery and the membrane changes produced by the oxidative ... More
Binding of alpha-synuclein affects the lipid packing in bilayers of small vesicles.
AuthorsKamp F, Beyer K
JournalJ Biol Chem
PubMed ID16455667
The intracellular deposition of fibrillar aggregates of alpha-synuclein is a characteristic feature of Parkinson disease. Alternatively, as a result of its unusual conformational plasticity, alpha-synuclein may fold into an amphipathic helix upon contact with a lipid-water interface. Using spin label ESR and fluorescence spectroscopy, we show here that alpha-synuclein affects ... More
Domain-specific lipid distribution in macrophage plasma membranes.
AuthorsGaus K, Rodriguez M, Ruberu KR, Gelissen I, Sloane TM, Kritharides L, Jessup W
JournalJ Lipid Res
PubMed ID15863834
Lipid rafts, defined as cholesterol- and sphingolipid-rich domains, provide specialized lipid environments understood to regulate the organization and function of many plasma membrane proteins. Growing evidence of their existence, protein cargo, and regulation is based largely on the study of isolated lipid rafts; however, the consistency and validity of common ... More
Plasma membrane polarity of polymorphonuclear leucocytes from children with primary ciliary dyskinesia.
AuthorsFiorini R, Littarru GP, Coppa GV, Kantar A
JournalEur J Clin Invest
PubMed ID10849021
BACKGROUND: Polymorphonuclear leucocytes (PMN) from subjects with primary ciliary dyskinesia (PCD) can have abnormal locomotory systems. The locomotory activity of PMN is the result of biochemical events mediated by the plasma membrane. In this study we investigated plasma membrane polarity of PMN from children with PCD. DESIGN: Membrane polarity was ... More
Determination of the contact energies between a regulator of G protein signaling and G protein subunits and phospholipase C beta 1.
AuthorsDowal L, Elliott J, Popov S, Wilkie TM, Scarlata S
JournalBiochemistry
PubMed ID11148035
Cell signaling proteins may form functional complexes that are capable of rapid signal turnover. These contacts may be stabilized by either scaffolding proteins or multiple interactions between members of the complex. In this study, we have determined the affinities between a regulator of G protein signaling protein, RGS4, and three ... More
Mechanisms by which elevated intracellular calcium induces S49 cell membranes to become susceptible to the action of secretory phospholipase A2.
AuthorsWilson HA, Waldrip JB, Nielson KH, Judd AM, Han SK, Cho W, Sims PJ, Bell JD
JournalJ Biol Chem
PubMed ID10206954
Exposure of S49 lymphoma cells to exogenous group IIA or V secretory phospholipase A2 (sPLA2) caused an initial release of fatty acid followed by resistance to further hydrolysis by the enzyme. This refractoriness was overcome by exposing cells to palmitoyl lysolecithin. This effect was specific in terms of lysophospholipid structure. ... More
Variable-angle total internal reflection fluorescence microscopy (VA-TIRFM): realization and application of a compact illumination device.
AuthorsStock K, Sailer R, Strauss WS, Lyttek M, Steiner R, Schneckenburger H
JournalJ Microsc
PubMed ID12839547
A novel compact illumination device in variable-angle total internal reflection fluorescence microscopy (VA-TIRFM) is described. This device replaces the standard condensor of an upright microscope. Light from different laser sources is delivered via a monomode fibre and focused onto identical parts of a sample under variable angles of total internal ... More
A two-photon view of an enzyme at work: Crotalus atrox venom PLA2 interaction with single-lipid and mixed-lipid giant unilamellar vesicles.
AuthorsSanchez SA, Bagatolli LA, Gratton E, Hazlett TL
JournalBiophys J
PubMed ID11916878
We describe the interaction of Crotalus atrox-secreted phospholipase A2 (sPLA2) with giant unilamellar vesicles (GUVs) composed of single and binary phospholipid mixtures visualized through two-photon excitation fluorescent microscopy. The GUV lipid compositions that we examined included 1-palmitoyl-2-oleoyl-phosphatidylcholine, 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), and 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) (above their gel-liquid crystal transition temperatures) and two ... More
Inhibition of phospholipase C-delta 1 catalytic activity by sphingomyelin.
We measured the ability of sphingomyelin (SPM) to inhibit phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] hydrolysis catalyzed by human phospholipase C-delta 1 (PLC-delta 1) in model membranes and detergent phospholipid mixed micelles. SPM strongly inhibited PLC-delta 1 catalytic activity measured in large unilamellar vesicles (LUVs) composed of egg phosphatidylcholine (PC), PI(4,5)P2, and SPM ... More