Interaction of membrane surface charges with the reconstituted ADP/ATP-carrier from mitochondria.
AuthorsKrämer R
JournalBiochim Biophys Acta
PubMed ID6313053
'Various modulating influences of negative and positive membrane charges on binding and transport properties of the reconstituted ADP/ATP carrier from mitochondria were investigated. The results are interpreted in terms of functional and structural asymmetries of the adenine nucleotide carrier embedded in the liposomal membrane. The surface potential of liposomes was ... More
Interaction of trans-parinaric acid with phosphatidylcholine bilayers: comparison with the effect of other fluorophores.
AuthorsBen Yashar V, Menashe M, Biltonen RL, Johnson ML, Barenholz Y
JournalBiochim Biophys Acta
PubMed ID3663661
'The effect of the fluorophore trans-parinaric acid on the structure of lipid bilayer was studied and compared with the effect of other ''perturbants''. These include commonly used fluorophores (diphenylhexatriene, heptadecylhydroxycoumarin, cis-parinaric acid and two fatty acids, palmitic and oleic acids). Differential scanning calorimetry (DSC) and proton nuclear magnetic resonance techniques ... More
Hypoxic modulation of manganese superoxide dismutase promoter activity and gene expression in lung epithelial cells.
AuthorsOhman T, Parish G, Jackson RM
JournalAm J Respir Cell Mol Biol
PubMed ID10385600
'We investigated the effects of hypoxia (< 2.5% O2) on rat manganese superoxide dismutase (MnSOD) gene promoter-luciferase reporter constructs in transiently transfected lung epithelial cells (A549, L2, and E1A-T2) and fibroblasts (R9Ab). We cloned MnSOD promoter-luciferase reporter constructs (numbers refer to length in base pairs [bp] in the 5'' direction ... More
Interaction of alpha-tocopherol with model human high-density lipoproteins.
AuthorsMassey JB, Pownall HJ
JournalBiophys J
PubMed ID9826613
'The effects of alpha-tocopherol on the properties of model high-density lipoproteins (HDLs), composed of human apolipoprotein A-I and dimyristoylphosphatidylcholine, were investigated by physicochemical methods. The intrinsic fluorescence of alpha-tocopherol and its effects on the polarization of fluorescence of 1,6-diphenyl-1,3,5-hexatriene, which probes the hydrocarbon region of the lipids, and 4-heptadecyl-7-hydroxycoumarin, which ... More
Lipid and protein contributions to the membrane surface potential of vesicular stomatitis virus probed by a fluorescent pH indicator, 4-heptadecyl-7-hydroxycoumarin.
AuthorsPal R, Petri WA, Barenholz Y, Wagner RR
JournalBiochim Biophys Acta
PubMed ID6299350
'The surface potential of membranes of vesicular stomatitis virus and liposomes was determined by shift of ionization over a wide pH range of the membrane-inserted fluorophore, 4-heptadecyl-7-hydroxycoumarin. Incorporation into sonicated vesicles of negatively charged phosphatidylserine markedly increased the surface potential of uncharged phosphatidylcholine, but no significant effect on surface potential ... More
Structure, stability, and thermodynamics of lamellar DNA-lipid complexes.
AuthorsHarries D, May S, Gelbart WM, Ben-Shaul A
JournalBiophys J
PubMed ID9649376
'We develop a statistical thermodynamic model for the phase evolution of DNA-cationic lipid complexes in aqueous solution, as a function of the ratios of charged to neutral lipid and charged lipid to DNA. The complexes consist of parallel strands of DNA intercalated in the water layers of lamellar stacks of ... More
Lipid coumarin dye as a probe of interfacial electrical potential in biomembranes.
AuthorsFromherz P
JournalMethods Enzymol
PubMed ID2593847
Surface properties of native human plasma lipoproteins and lipoprotein models.
AuthorsMassey JB, Pownall HJ
JournalBiophys J
PubMed ID9533698
'Plasma lipoprotein surface properties are important but poorly understood determinants of lipoprotein catabolism. To elucidate the relation between surface properties and surface reactivity, the physical properties of surface monolayers of native lipoproteins and lipoprotein models were investigated by fluorescent probes of surface lipid fluidity, surface lateral diffusion, and interfacial polarity, ... More
Characterization of liposomes and other lipid assemblies by multiprobe fluorescence polarization.
AuthorsBorenstain V, Barenholz Y
JournalChem Phys Lipids
PubMed ID8242830
'This minireview describes the use of fluorescence polarization to characterize the dynamics and organization of biological membranes, lipoproteins, liposomes and other lipid-based assemblies. The advantages, disadvantages and limitations of this method are discussed. There is special emphasis on the multiprobe approach, which can monitor various parts of the lipid membrane ... More
A new method for investigation of lipid assemblies with a lipoid pH indicator in monomolecular films.
AuthorsFromherz P
JournalBiochim Biophys Acta
PubMed ID4752288
Interfacial pH at electrically charged lipid monolayers investigated by the lipoid pH-indicator method.
AuthorsFromherz P, Masters B
JournalBiochim Biophys Acta
PubMed ID4844172
Membrane surface potential of Spiroplasma floricola.
AuthorsSchummer U, Schiefer HG
JournalFEBS Lett
PubMed ID3410045
Anionic charges, cytochemically identified as lipid phosphate groups, cover the outer membrane surface of Spiroplasma floricola. They induce a negative membrane surface potential which affects the distribution of ions, including protons. Accordingly, the pH at the interface differs from the bulk pH. By using the fluorescent lipoid pH indicator 4-heptadecyl-7-hydroxycoumarin, ... More
Fluorescence studies of dipalmitoylphosphatidylcholine vesicles reconstituted with the glycoprotein of vesicular stomatitis virus.
AuthorsPetri WA, Pal R, Barenholz Y, Wagner RR
JournalBiochemistry
PubMed ID6264945
The vesicular stomatitis virus glycoprotein (G) was reconstituted into dipalmitoylphosphatidylcholine (DPPC) vesicles by detergent dialysis. The DPPC gel to liquid-crystalline phase transition of the DPPC-G protein vesicles was monitored by the fluorescence anisotrophy of trans-paranaric acid, 16-(9-anthroyloxy)palmitoylglucocerebroside, 1,6-diphenyl-1,3,5-hexatriene, and 4-heptadecyl-7-hydroxycoumarin. The DPPC transition temperature measured by all four fluorescent probes ... More
Synergy between cationic lipid and co-lipid determines the macroscopic structure and transfection activity of lipoplexes.
AuthorsFerrari ME, Rusalov D, Enas J, Wheeler CJ
JournalNucleic Acids Res
PubMed ID11937635
The large number of cytofectin and co-lipid combinations currently used for lipoplex-mediated gene delivery reflects the fact that the optimal cytofectin/co-lipid combination varies with the application. The effects of structural changes in both cytofectin and co-lipid were systematically examined to identify structure-activity relationships. Specifically, alkyl chain length, degree of unsaturation ... More
External calcium, intrasynaptosomal free calcium and neurotransmitter release.
AuthorsAshley RH
JournalBiochim Biophys Acta
PubMed ID2867783
In a physiological medium the resting membrane potential of synaptosomes from guinea-pig cerebral cortex, estimated from rhodamine 6G fluorescence measurements, was nearly -50mV. This agreed with calculations using the Goldman-Hodgkin-Katz equation. With external [Ca2+] less than or equal to 3 mM veratridine depolarisation (to -30 mV) was accompanied by increases ... More
Thermodynamics of cationic lipid-DNA complex formation as studied by isothermal titration calorimetry.
AuthorsPozharski E, MacDonald RC
JournalBiophys J
PubMed ID12080142
The detailed analysis of the cationic lipid-DNA complex formation by means of isothermal titration calorimetry is presented. Most experiments were done using 1,2-dioleyl-sn-glycero-3-ethylphosphocholine (EDOPC), but basic titrations were also done using DOTAP, DOTAP:DOPC, and DOTAP:DOPE mixtures. Complex formation was endothermic with less than 1 kcal absorbed per mole of lipid ... More
Electrostatic and structural properties of complexes involving plasmid DNA and cationic lipids commonly used for gene delivery.
AuthorsZuidam NJ, Barenholz Y
JournalBiochim Biophys Acta
PubMed ID9459590
The present study is aimed to characterize the interactions between plasmid DNA and cationic, large unilamellar vesicles, 110+/-20nm in size, composed of lipids commonly used for transfections including DOTAP/DOPE (mole ratio 1/1), DOTAP/DOPC (mole ratio 1/1), 100% DOTAP, or DC-CHOL/DOPE (mole ratio 1/1). [Abbreviations:DOTAP, N-(1-(2,3-dioleoyloxy)propyl)-N,N,N-trimethylammonium chloride; DOPE, 1,2-dioleoyl-sn-glycero-3-phosphatidylethanolamine; DOPC, 1,2-dioleoyl-sn-glycero-3-phosphatidylcholine; ... More
Characterization of DNA/lipid complexes by fluorescence resonance energy transfer.
AuthorsMadeira C, Loura LM, Aires-Barros MR, Fedorov A, Prieto M
JournalBiophys J
PubMed ID14581211
Fluorescence resonance energy transfer (FRET) is a potential method for the characterization of DNA-cationic lipid complexes (lipoplexes). In this work, we used FRET models assuming a multilamellar lipoplex arrangement. The application of these models allows the determination of the distance between the fluorescent intercalator on the DNA and a membrane ... More
Location of functional centers in the microsomal cytochrome P450 system.
AuthorsCenteno F, Gutiérrez-Merino C
JournalBiochemistry
PubMed ID1390631
Fluorescence quenching and energy-transfer studies have been carried out to determine the position of FAD and FMN groups of NADPH-cytochrome P450 reductase and of the heme and substrate groups of cytochrome P450 with respect to the lipid/water interphase. Quenching by iodine of the fluorescence of the flavins of the reductase ... More
Fluorescent probes DPH, TMA-DPH and C17-HC induce erythrocyte exovesiculation.
AuthorsSaldanha C, Santos NC, Martins-Silva J
JournalJ Membr Biol
PubMed ID12422273
An experimental approach has been developed to study human erythrocyte vesiculation, using the fluorescent probes diphenylhexatriene (DPH), trimethylamino-diphenylhexatriene (TMA-DPH) and heptadecyl-hydroxycoumarin (C17-HC). Acetylcholinesterase (AChE) enzyme activity measurements confirmed the presence of exovesicles released from erythrocyte membranes labeled with DPH, TMA-DPH or C17-HC. The fluorescence intensity and anisotropy values obtained showed ... More
The interaction of cholesterol and cholest-4-en-3-one with dipalmitoylphosphatidylcholine. Comparison based on the use of three fluorophores.
AuthorsBen-Yashar V, Barenholz Y
JournalBiochim Biophys Acta
PubMed ID2804109
This study compares cholesterol-phospholipid and cholest-4-en-3-one-phospholipid interactions by their effect on thermotropic behavior of dipalmitoylphosphatidylcholine bilayers. This was approached by determining the temperature-dependent steady-state fluorescence anisotropy of three fluorophores; diphenylhexatriene (DPH), hydroxy-coumarin (HC) and trans-parinaric acid (TPA). The fluorophores monitor different lateral and vertical locations of the lipid bilayers; DPH ... More
Characterization of the core and surface of human plasma lipoproteins. A study based on the use of five fluorophores.
AuthorsBen-Yashar V, Barenholz Y
JournalChem Phys Lipids
PubMed ID1813177
The physical properties of the core and the surface of five classes of human plasma lipoproteins were investigated using five fluorescent probes. The location of the fluorescence probes in the lipoprotein assembly was determined using collisional quenching and resonance energy transfer. The fluorophores monitor different regions of the lipoproteins, as ... More
Lamellarity of cationic liposomes and mode of preparation of lipoplexes affect transfection efficiency.
AuthorsZuidam NJ, Hirsch-Lerner D, Margulies S, Barenholz Y
JournalBiochim Biophys Acta
PubMed ID10407072
Transfection of NIH-3T3 cells by a human growth hormone expression vector complexed with liposomes composed of N-(1-(2, 3-dioleoyloxy)propyl)-N,N,N-trimethylammonium chloride (DOTAP) with or without helper lipids was studied. The transfection efficiency was dependent on the lamellarity of the liposomes used to prepare the lipoplexes. Multilamellar vesicles (MLV) were more effective than ... More
Characterization of the fluorophore 4-heptadecyl-7-hydroxycoumarin: a probe for the head-group region of lipid bilayers and biological membranes.
AuthorsPal R, Petri WA, Ben-Yashar V, Wagner RR, Barenholz Y
JournalBiochemistry
PubMed ID2986680
The fluorophore 4-heptadecyl-7-hydroxycoumarin was used as a probe to study the properties of phospholipid bilayers at the lipid-water interface. To this end, the steady-state fluorescence anisotropy, the differential polarized phase fluorometry, and the emission lifetime of the fluorophore were measured in isotropic viscous medium, in lipid vesicles, and in the ... More
Effect of various detergents on protein migration in the second dimension of two-dimensional gels.
AuthorsLopez MF, Patton WF, Utterback BL, Chung-Welch N, Barry P, Skea WM, Cambria RP
JournalAnal Biochem
PubMed ID1807160
Two-dimensional gel electrophoresis (2D)1 is a powerful technique used to separate complex protein mixtures. The technique involves the separation of proteins by charge in the first dimension and by molecular weight in the second dimension. The effect of substituting various detergents for sodium dodecyl sulfate (SDS) in the second dimension ... More
Interaction of oligonucleotides with cationic lipids: the relationship between electrostatics, hydration and state of aggregation.
AuthorsMeidan VM, Cohen JS, Amariglio N, Hirsch-Lerner D, Barenholz Y
JournalBiochim Biophys Acta
PubMed ID10727612
Lipoplexes, which are spontaneously formed complexes between oligonucleotide (ODN) and cationic lipid, can be used to deliver ODNs into cells, both in vitro and in vivo. The present study was aimed at characterizing the interactions associated with the formation of lipoplexes, specifically in terms of electrostatics, hydration and particle size. ... More
The role of organ vascularization and lipoplex-serum initial contact in intravenous murine lipofection.
AuthorsSimberg D, Weisman S, Talmon Y, Faerman A, Shoshani T, Barenholz Y
JournalJ Biol Chem
PubMed ID12869564
Following intravenous administration of cationic lipid-DNA complexes (lipoplexes) into mice, transfection (lipofection) occurs predominantly in the lungs. This was attributed to high entrapment of lipoplexes in the extended lung vascular tree. To determine whether lipofection in other organs could be enhanced by increasing the degree of vascularization, we used a ... More
Characterization of DNA-lipid complexes commonly used for gene delivery.
AuthorsZuidam NJ, Barenholz Y
JournalInt J Pharm
PubMed ID10361152
Cationic liposomes are used to deliver genes into cells. Here we describe some poorly understood basic features of DNA-lipid complexes (lipoplexes), especially the electrostatics, stability and DNA structure of lipoplexes, and their effects on transfection (lipofection). Use of the lipophilic, pH-sensitive fluorophore 4-heptadecyl-7-hydroxycoumarin, in combination with Gouy-Chapman calculations, showed that ... More
Electrostatic parameters of cationic liposomes commonly used for gene delivery as determined by 4-heptadecyl-7-hydroxycoumarin.
AuthorsZuidam NJ, Barenholz Y
JournalBiochim Biophys Acta
PubMed ID9371413
Cationic liposomes are used to deliver genes into cells in vitro and in vivo. The present study is aimed to characterize the electrostatic parameters of cationic, large unilamellar vesicles, 110 +/- 20 nm in size, composed of DOTAP/DOPE (mole ratio 1/1), DOTAP/DOPC (mole ratio 1/1), 100% DOTAP, DMRIE/DOPE 1/1, or ... More