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
Effects of lindane on membrane fluidity: intramolecular excimerization of a pyrene derivative and polarization of diphenylhexatriene.
AuthorsAntunes-Madeira MC, Almeida LM, Madeira VM
JournalBiochim Biophys Acta
PubMed ID1689182
'Fluorescence polarization studies of 1,6-diphenyl-1,3,5-hexatriene (DPH) have been compared with the excimer/monomer fluorescence intensity ratio (I''/I) of 1,3-di(2-pyrenyl)propane, (2Py(3)2Py). This ratio permits evaluation of changes in fluidity of the outer regions of the bilayer, where 2Py(3)2Py preferentially distributes. On the other hand, fluorescence polarization of DPH reports the structural order ... More
Effects of DDE on the fluidity of model and native membranes: implications for the mechanisms of toxicity.
AuthorsAntunes-Madeira Mdo C, Madeira VM
JournalBiochim Biophys Acta
PubMed ID8318533
'2,2-Bis(p-chlorophenyl)-1,1-dichloroethylene (DDE) interaction with model and native membranes was studied by means of fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene (DPH), probing the bilayer core, and by intramolecular excimerization of 1,3-di(1-pyrenyl) propane (Py(3)Py), probing the outer regions of the bilayer. In the gel phase of DMPC bilayers, DDE induces concentration-dependent fluidizing effects into ... More
The active metabolite hydroxytamoxifen of the anticancer drug tamoxifen induces structural changes in membranes.
AuthorsCustódio JB, Almeida LM, Madeira VM
JournalBiochim Biophys Acta
PubMed ID8274502
'The effects of hydroxytamoxifen (OHTAM) on lipid organization of pure phospholipid liposomes, native sarcoplasmic reticulum (SR) membranes and liposomes of SR lipids were evaluated by intramolecular excimer formation of 1,3-di(1-pyrenyl)propane (Py(3)Py) and by fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene (DPH) and its derivative 3-[p-(6-phenyl)-1,3,5-hexatrienyl]phenylpropionic acid (DPH-PA). OHTAM promotes alterations in the thermotropic ... More
Escherichia coli membrane fluidity as detected by excimerization of dipyrenylpropane: sensitivity to the bacterial fatty acid profile.
AuthorsMejía R, Gómez-Eichelmann MC, Fernández MS
JournalArch Biochem Biophys
PubMed ID10415123
'A coordinated study of membrane fluidity and fatty acid composition has been carried out in Escherichia coli W3110. The lipid acyl chain profile of the bacteria, altered by growing cells in steady state at 30, 37, 42, or 45 degrees C, was determined by gas chromatography of the fatty acid ... More
Fluidity of sarcoplasmic reticulum membranes investigated with dipyrenylpropane, an intramolecular excimer probe.
AuthorsAlmeida LM, Vaz WL, Zachariasse KA, Madeira VM
JournalBiochemistry
PubMed ID7150540
'Intramolecular excimer formation with 1,3-di(1-pyrenyl)propane was used to probe the fluidity of sarcoplasmic reticulum (SR) membranes where the probe could be incorporated (in a probe/lipid molar ratio of 1/2000 or less) without inducing any detectable damage. The temperature was varied between -1 and 40 degrees C. The fluidity of the ... More
Pyrene eximer mapping in cultured fibroblasts by ratio imaging and time-resolved microscopy.
AuthorsDix JA, Verkman AS
JournalBiochemistry
PubMed ID2331474
'The kinetics of pyrene eximer formation provide a measure of lateral diffusibility in bilayer membranes. Swiss 3T3 fibroblasts were labeled with pyrene, pyrenedecanoic acid (PDA) and 1,3-bis(1 pyrene) propane (BPP) by incubation in the presence of Pluronic F127. Single-cell emission spectra obtained by epifluorescence microscopy (excitation 350 nm) with photodiode ... More
Investigation of human erythrocyte ghost membranes with intramolecular excimer probes.
AuthorsZachariasse KA, Vaz WL, Sotomayor C, Kühnle W
JournalBiochim Biophys Acta
PubMed ID7104326
'Human erythrocyte ghost membranes have been investigated using two intramolecular excimer probes, di(1-pyrenyl)propane and di(1-pyrenylmethyl) ether. Values for the viscosity of the direct probe environment in the ghost membranes range from 76 cP at 37 degrees C to 570 cP at 5 degrees C, as reported for di(1-pyrenyl(propane, with liquid ... More
Fluidity of bacterial membrane lipids monitored by intramolecular excimerization of 1.3-di(2-pyrenyl)propane.
AuthorsJurado AS, Almeida LM, Madeira VM
JournalBiochem Biophys Res Commun
PubMed ID2018528
'Intramolecular excimer formation of 1,3-di(2-pyrenyl)propane was used to study the fluidity of liposomes prepared from membrane polar lipids of Bacillus stearothermophilus. On the basis of spectral data, local polarity and polarizability parameters were established suggesting that the probe molecules are located well inside the membranes, but displaced towards the polar ... More
Effect of short-chain primary alcohols on fluidity and activity of sarcoplasmic reticulum membranes.
AuthorsAlmeida LM, Vaz WL, Stümpel J, Madeira VM
JournalBiochemistry
PubMed ID2945592
'Intramolecular excimer formation with the fluorescent probe 1,3-di(1-pyrenyl)propane, differential scanning calorimetry, and X-ray diffraction were used to assess the effect of ethanol, 1-butanol, and 1-hexanol on the bilayer organization in model membranes, sarcoplasmic reticulum (SR) lipids and native SR membranes. These alcohols have fluidizing effects on membranes and lower the ... More
An intramolecular excimer forming probe used to study the interaction of alpha-lactalbumin with model membranes.
AuthorsDangreau H, Joniau M, De Cuyper M, Hanssens I
JournalBiochemistry
PubMed ID7150417
'The nonconjugated bichromophoric molecule 1,3-di(1-pyrenyl)propane shows, besides the pyrene monomer fluorescence, a structureless emission due to an intramolecular excited dimer (excimer). In the case of intramolecular excimer forming systems, the ratio of the emission intensities of excimer vs. monomer (IE/IM) is sensitive to changes in membrane structure as will be ... More
Perturbation of the fluidity of the erythrocyte membrane with ionophoric antibiotics and lipophilic anaesthetics.
AuthorsAbu-Salah KM
JournalBiochem Pharmacol
PubMed ID1741772
'The fluidity of the rat erythrocyte membrane was evaluated by measurement of excimer fluorescence of an intra-molecular forming fluorophore, 1,3-di(1-pyrenyl)propane. The polyene ionophoric antibiotics, amphotericin B and nystatin, were found to fluidize the erythrocyte membrane, as assessed by the increase in the excimer/monomer fluorescence intensity ratio, by 42 and 13%, ... More
Physical studies on membrane lipids of Bacillus stearothermophilus temperature and calcium effects.
AuthorsJurado AS, Pinheiro TJ, Madeira VM
JournalArch Biochem Biophys
PubMed ID1898060
'Bacillus stearothermophilus was grown at the optimal temperature range (center, 65 degrees C), below it (48 and 55 degrees C), and above it (68 degrees C), in a complex medium with or without 2.5 mM Ca2+. The Ca(2+)-supplement improves growth at sub- and supraoptimal temperatures and extends it to higher ... More
Methyl-beta-cyclodextrins and liposomes as water-soluble carriers for cholesterol incorporation into membranes and its evaluation by a microenzymatic fluorescence assay and membrane fluidity-sensitive dyes.
AuthorsHärtel S, Diehl HA, Ojeda F
JournalAnal Biochem
PubMed ID9570841
'A variety of methods to incorporate cholesterol into lipid membrane systems have been applied with varying success. We tested an incorporation method based on cholesterol-loaded methyl-beta-cyclodextrins and compared it to a method that uses cholesterol-loaded liposomes. With methyl-beta-cyclodextrin, we increased the cholesterol content in microsomal membranes to almost the fourfold ... More
Investigation of human blood platelets with fluorescence spectroscopy.
AuthorsViriot ML, Collin T, Gaillard S, Stoltz JF, Andre JC
JournalBiorheology Suppl
PubMed ID6591993
Intramolecular excimer formation of dipyrenylpropane was investigated in human blood platelets. The ratio of the emission intensities of excimer to monomer (IE/IM) is sensitive to changes in lipidic membrane structure, induced by external perturbations, such as cholesteryl hemisuccinate introduction and temperature. Lack of reliable "microviscosities" determinations could be due to ... More
Alterations in lipid composition and fluidity of liver plasma membranes in copper-deficient rats.
AuthorsLei KY, Rosenstein F, Shi F, Hassel CA, Carr TP, Zhang J
JournalProc Soc Exp Biol Med
PubMed ID2969111
In view of the importance of membrane fluidity on cell functions, the influence of phospholipid acyl groups on membrane fluidity, and the changes in lipid metabolism induced by copper (Cu) deficiency, this study was designed to examine the influence of dietary Cu on the lipid composition and fluidity of liver ... 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
Dietary induction of acyl chain desaturases alters the lipid composition and fluidity of rat hepatocyte plasma membranes.
AuthorsStorch J, Schachter D
JournalBiochemistry
PubMed ID6324863
Rats were maintained on a regimen of intermittent starvation followed by refeeding a fat-free diet in order to induce hepatic acyl desaturase activities and other enzymes involved in lipid synthesis. The effects of the dietary regimen on the lipid composition and fluidity of isolated hepatocyte plasma membranes were compared to ... 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
Lipid peroxidation in sarcoplasmic reticulum membranes: effect on functional and biophysical properties.
AuthorsDinis TC, Almeida LM, Madeira VM
JournalArch Biochem Biophys
PubMed ID8384829
The fluorescent polyunsaturated parinaric acid (PnA) incorporated in sarcoplasmic reticulum membranes (SR) was used to probe the initial stages of membrane lipid peroxidation. The experimental set up of the PnA assay was investigated by means of several peroxidation initiators to ascertain peroxidation conditions. This assay in SR is particularly useful ... More
The anticancer drug tamoxifen induces changes in the physical properties of model and native membranes.
AuthorsCustódio JB, Almeida LM, Madeira VM
JournalBiochim Biophys Acta
PubMed ID8347666
The interactions of tamoxifen with lipid bilayers of model and native membranes were investigated by fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene (DPH) and by intramolecular excimer formation of 1,3-di(1-pyrenyl)propane (Py(3)Py). The effects of TAM of liposomes of DMPC, DPPC and DSPC are temperature dependent. In the fluid phase, TAM reduces dynamics of ... More
Modulation of sarcoplasmic reticulum Ca2+-pump activity by membrane fluidity.
AuthorsAlmeida LM, Vaz WL, Zachariasse KA, Madeira VM
JournalBiochemistry
PubMed ID6238620
Intramolecular excimerization of 1,3-di-1-pyrenylpropane [Py(3)Py] was used to assess the fluidity of sarcoplasmic reticulum membranes (SR); on the basis of the spectral data, the probe incorporates completely inside the membrane probably somewhere close to the polar head groups of phospholipid molecules, however not in the very hydrophobic core. The excimerization ... More
Use of fluorescent probes that form intramolecular excimers to monitor structural changes in model and biological membranes.
AuthorsMelnick RL, Haspel HC, Goldenberg M, Greenbaum LM, Weinstein S
JournalBiophys J
PubMed ID7248471
1,3-dipyrenylpropane (PC3P) and bis(4-biphenylmethyl)ether, two molecules that form intramolecular excimers, were embedded in phospholipid vesicles and biological membranes to monitor dynamic properties of membrane lipids. Excimer formation was evaluated from determinations of excimer to monomer emission intensity ratios (ID/IM). ID/IM values of PC3P and bis(4-biphenylmethyl)ether were reduced when cholesterol was ... More