Membrane vesicles containing the Sendai virus binding glycoprotein, but not the viral fusion protein, fuse with phosphatidylserine liposomes at low pH.
AuthorsChejanovsky N, Zakai N, Amselem S, Barenholz Y, Loyter A
JournalBiochemistry
PubMed ID3021204
Membrane vesicles containing the Sendai virus hemagglutinin/neuraminidase (HN) glycoprotein were able to induce carboxyfluorescein (CF) release from loaded phosphatidylserine (PS) but not loaded phosphatidylcholine (PC) liposomes. Similarly, fluorescence dequenching was observed only when HN vesicles, bearing self-quenched N-(7-nitro-2,1,3-benzoxadiazol-4-yl)phosphatidylethanolamine (N-NBD-PE), were incubated with PS but not PC liposomes. Thus, fusion between ... More
Receptor-mediated endocytosis of antibody-opsonized liposomes by tumor cells.
AuthorsLeserman LD, Weinstein JN, Blumenthal R, Terry WD
JournalProc Natl Acad Sci U S A
PubMed ID7001454
'Specific receptor-mediated delivery of the contents of small, sonicated liposomes was studied with three murine tumor cell types: an IgG Fc receptor-negative nonphagocytic line (EL4); an Fc receptor-positive phagocytic line (P388D1); and an Fc receptor-positive nonphagocytic line (P388). The liposomes (formed from phosphatidylcholines, cholesterol, and dinitrophenyl-substituted phosphatidylethanolamine) contained carboxyfluorescein as ... More
Reconstitution of functional water channels in liposomes containing purified red cell CHIP28 protein.
AuthorsZeidel ML, Ambudkar SV, Smith BL, Agre P
JournalBiochemistry
PubMed ID1510932
'Water rapidly crosses the plasma membranes of red blood cells (RBCs) and renal tubules through highly specialized channels. CHIP28 is an abundant integral membrane protein in RBCs and renal tubules, and Xenopus laevis oocytes injected with CHIP28 RNA exhibit high osmotic water permeability, Pf [Preston et al. (1992) Science 256, ... More
Mechanistic studies of lantibiotic-induced permeabilization of phospholipid vesicles.
AuthorsDriessen AJ, van den Hooven HW, Kuiper W, van de Kamp M, Sahl HG, Konings RN, Konings WN
JournalBiochemistry
PubMed ID7849020
'Nisin is a cationic polycyclic bacteriocin secreted by some lactic acid bacteria. Nisin has previously been shown to permeabilize liposomes. The interaction of nisin was analyzed with liposomes prepared of the zwitterionic phosphatidylcholine (PC) and the anionic phosphatidylglycerol (PG). Nisin induces the release of 6-carboxyfluorescein and other small anionic fluorescent ... More
Luminal pH regulated calcium release kinetics in sarcoplasmic reticulum vesicles.
AuthorsDonoso P, Beltrán M, Hidalgo C
JournalBiochemistry
PubMed ID8873610
'Calcium binding to triads isolated from rabbit skeletal muscle followed a single hyperbolic function in the pH range 5.5-8.0. Maximal binding was obtained at pH 8.0; decreasing the pH decreased the binding capacity and, at pH < or = 6.0, increased Kd 2-fold. These results indicate that lowering the pH ... More
Functional water channels and proton pumps are in separate populations of endocytic vesicles in toad bladder granular cells.
AuthorsWang YX, Shi LB, Verkman AS
JournalBiochemistry
PubMed ID1901021
'Functional water channels are retrieved by endocytosis from the apical membrane of toad bladder granular cells in response to vasopressin [Shi, L.-B., & Verkman, A.S. (1989) J. Gen. Physiol. 94, 1101-1115]. To examine whether endocytic vesicles which contain the vasopressin-sensitive water channel fuse with acidic vesicles for entry into a ... More
Oriented reconstitution of red cell membrane proteins and assessment of their transmembrane disposition by immunoquenching of fluorescence.
AuthorsDarmon A, Bar-Noy S, Ginsburg H, Cabantchik ZI
JournalBiochim Biophys Acta
PubMed ID3893545
'The two major membrane glycoproteins of human red cells, glycophorin and band 3, the anion exchange protein, were isolated from cells exofacially labeled with fluorescein and reconstituted into vesicles with defined transmembrane disposition. Uniform orientation of polypeptides was accomplished by two procedures: Vesicles with single protein units were obtained by ... More
Neuronal coupling in the developing mammalian retina.
AuthorsPenn AA, Wong RO, Shatz CJ
JournalJ Neurosci
PubMed ID8207489
'During the first 3 weeks of postnatal development in the ferret retina, cells in the ganglion cell layer spontaneously generate waves of electrical activity that travel across the retina in the absence of mature photoreceptors (Meister et al., 1991; Wong et al., 1993). Since few chemical synapses are present at ... More
Functional analysis of nodulin 26, an aquaporin in soybean root nodule symbiosomes.
AuthorsRivers RL, Dean RM, Chandy G, Hall JE, Roberts DM, Zeidel ML
JournalJ Biol Chem
PubMed ID9195927
'Upon infection of soybean roots, nitrogen-fixing bacteria become enclosed in a specific organelle known as the symbiosome. The symbiosome membrane (SM) is a selectively permeable barrier that controls metabolite flux between the plant cytosol and the symbiotic bacterium inside. Nodulin 26 (NOD 26), a member of the aquaporin (AQP) water ... More
Turning of nerve growth cones induced by neurotransmitters.
AuthorsZheng JQ, Felder M, Connor JA, Poo MM
JournalNature
PubMed ID8139655
'Pathfinding by growing nerve processes in the developing nervous system depends on the turning response of the growing tip, the growth cone, to extracellular guidance cues. There is evidence in vivo and in cell culture that some growth cones exhibit chemotropic behaviour, but the identity of endogenous chemoattractants remains elusive. ... More
Lipids favoring inverted phase enhance the ability of aerolysin to permeabilize liposome bilayers.
AuthorsAlonso A, Goñi FM, Buckley JT
JournalBiochemistry
PubMed ID11087349
'Channel formation by the bacterial toxin aerolysin follows oligomerization of the protein to produce heptamers that are capable of inserting into lipid bilayers. How insertion occurs is not understood, not only for aerolysin but also for other proteins that can penetrate membranes. We have studied aerolysin channel formation by measuring ... More
Focusing of nitric oxide mediated nitrosation and oxidative nitrosylation as a consequence of reaction with superoxide.
AuthorsEspey MG, Thomas DD, Miranda KM, Wink DA
JournalProc Natl Acad Sci U S A
PubMed ID12177414
'The impact of nitric oxide (NO) synthesis on different biological cascades can rapidly change dependent on the rate of NO formation and composition of the surrounding milieu. With this perspective, we used diaminonaphthalene (DAN) and diaminofluorescein (DAF) to examine the nitrosative chemistry derived from NO and superoxide (O2-) simultaneously generated ... More
Mass action kinetics of phosphatidylserine vesicle fusion as monitored by coalescence of internal vesicle volumes.
AuthorsNir S, Bentz J, Wilschut J
JournalBiochemistry
PubMed ID7470447
'The kinetics of Ca2+-induced fusion of sonicated phosphatidylserine vesicles is analyzed by means of the mass action model. The results of calculations are shown to simulate the experimental results for the mixing of aqueous vesicle volumes, release of vesicle contents and for the observed increase in light scattering [Wilschut, J., ... More
Communication compartments in the gastrulating mouse embryo.
AuthorsKalimi GH, Lo CW
JournalJ Cell Biol
PubMed ID3392100
'We characterized the pattern of gap junctional communication in the 7.5-d mouse embryo (at the primitive streak or gastrulation stage). First we examined the pattern of dye coupling by injecting the fluorescent tracers, Lucifer Yellow or carboxyfluorescein, and monitoring the extent of dye spread. These studies revealed that cells within ... More
Cell-to-cell diffusion of fluorescent dyes in paired ventricular cells.
AuthorsImanaga I, Kameyama M, Irisawa H
JournalAm J Physiol
PubMed ID3812712
'The intracellular and cell-to-cell diffusion of fluorescent dyes of various molecular sizes were studied in enzymatically isolated paired ventricular cells of the guinea pig heart. Fluorescein sodium (mol wt 332), 6-carboxyfluorescein (mol wt 376), Lucifer yellow CH (mol wt 457), lissamine rhodamine B-200 (mol wt 559), and tetraglycine-conjugated lissamine rhodamine ... More
Liposomes increase skin penetration of entrapped and non-entrapped hydrophilic substances into human skin: a skin penetration and confocal laser scanning microscopy study.
AuthorsVerma DD, Verma S, Blume G, Fahr A
JournalEur J Pharm Biopharm
PubMed ID12754000
'Liposomes have been extensively studied and suggested as a vehicle for topical drug delivery systems. However, the mechanism by which liposomes deliver drugs into intact skin is not fully understood. In the present study, we have tried to understand the mechanism of transport of hydrophilic drugs into the skin using ... More
Fusion of sphingomyelin vesicles induced by proteins from Taiwan cobra (Naja naja atra) venom. Interactions of zwitterionic phospholipids with cardiotoxin analogues.
AuthorsChien KY, Huang WN, Jean JH, Wu WG
JournalJ Biol Chem
PubMed ID1993698
'Egg sphingomyelin vesicles were used to assay aggregation/fusion activities of proteins from Taiwan (Naja naja atra) venom to avoid the problem of phospholipase A2 contamination during protein purification. It led to the identification of a new cardiotoxin (CTX) analogue protein (CTX V) with major aggregation/fusion, but few hemolysis, activities. On ... More
Continuous measurement of mitochondrial pH gradients in isolated hepatocytes by difference ratio spectroscopy.
AuthorsThomas PJ, Gaspers LD, Pharr C, Thomas JA
JournalArch Biochem Biophys
PubMed ID1898020
'The pH gradient, delta pH, present across the inner mitochondrial membrane in isolated rat hepatocytes was continuously monitored with a novel spectroscopic technique that utilizes the weak acid fluorescein. Unlike most cytosolic pH indicators, such as 2'',7''-bis(carboxyethyl)-5,(6)-carboxyfluorescein (BCECF), fluorescein freely distributes between the cytosolic and mitochondrial compartments. As is typical ... More
Interaction of partially structured states of acidic fibroblast growth factor with phospholipid membranes.
AuthorsMach H, Middaugh CR
JournalBiochemistry
PubMed ID7543282
'Although acidic fibroblast growth factor (aFGF) lacks a conventional signal sequence, it is often found complexed to sulfated proteoglycans on the external surface of cells. The protein also forms a "molten globule"-like state at neutral pH and physiological temperatures as well as at acidic pH in the presence of physiological ... More
Factors affecting the stability of dry liposomes.
AuthorsCrowe JH, Crowe LM
JournalBiochim Biophys Acta
PubMed ID3355821
'Previous studies have shown that liposomes can be preserved in the dry state in the presence of certain sugars, of which trehalose is particularly effective. There have been some discrepancies in results obtained by the various laboratories in which this phenomenon has been studied, both with respect to the efficacy ... More
Fusion of phospholipid vesicles with planar phospholipid bilayer membranes. I. Discharge of vesicular contents across the planar membrane.
AuthorsZimmerberg J, Cohen FS, Finkelstein A
JournalJ Gen Physiol
PubMed ID6247417
'Multilamellar phospholipid vesicles are introduced into the cis compartment on one side of a planar phospholipid bilayer membrane. The vesicles contain a water-soluble fluorescent dye trapped in the aqueous phases between the lamellae. If a vesicle containing n lamellae fuses with a planar membrane, an n-1 lamellar vesicle should be ... More
Photoinactivation of neurones axonally filled with the fluorescent dye 5(6)-carboxyfluorescein in the pond snail, Lymnaea stagnalis.
AuthorsKemenes G, Daykin K, Elliott CJ
JournalJ Neurosci Methods
PubMed ID1787741
'We describe a new, simple and reliable technique to fill molluscan neurones from their cut axons with sufficient fluorescent dye for photoinactivation experiments. The fluorescent dye 5(6)-carboxyfluorescein (5-CF) travels quickly up the nerves of the gastropod mollusc, Lymnaea stagnalis into the buccal ganglia and fills the cell bodies in 1-3 ... More
Plant sterol inhibition of abscisic acid-induced perturbations in phospholipid bilayers.
AuthorsStillwell W, Cheng YF, Wassall SR
JournalBiochim Biophys Acta
PubMed ID2141283
'Abscisic acid (ABA)-induced phospholipid bilayer perturbations (permeability and lipid vesicle aggregation) are shown to be reversed by incorporation of a commercially available mixture of plant sterols (60% beta-sitosterol, 27% campesterol and 13% dihydrobrassicasterol) into the membranes. As little and 5 membrane mol% plant sterol inhibits ABA-stimulated permeability of both saturated ... More
Cyclic AMP effects on cell-to-cell junctional membrane permeability during adipocyte differentiation of 3T3-L1 fibroblasts.
AuthorsAzarnia R, Russell TR
JournalJ Cell Biol
PubMed ID2981232
'Mouse 3T3-L1 fibroblast cells, also know as preadipocytes, differentiate in vitro into adipocytes when treated with promoting agents and acquire numerous properties characteristic of mature fat cells. We studied junctional cell-to-cell communication by measuring the incidence of electrical coupling and transfer of carboxy-fluorescein among these cells. When 3T3-L1 cells were ... More
Structural organization of interphase 3T3 fibroblasts studied by total internal reflection fluorescence microscopy.
AuthorsLanni F, Waggoner AS, Taylor DL
JournalJ Cell Biol
PubMed ID3980580
'We studied the laminar organization of 3T3 fibroblast cells growing on glass slides by use of total internal reflection illumination to excite fluorescence emission (TIRF) from labeled molecules and stained cellular compartments that are very close to the cell-substrate contact region. Mitochondria, distant from the contact regions and stained with ... More
Effect of covalent attachment of immunoglobulin fragments on liposomal integrity.
'Liposome stability during and after covalent coupling of Fab'' antibody fragments was investigated. Large unilamellar vesicles containing entrapped 5(6)-carboxyfluorescein (CF) as a marker for liposomal integrity were prepared by extrusion through polycarbonate membranes. N-[4-(p-Maleimidophenyl)-butyryl]phosphatidylethanolamine (MPB-PE) was employed as a liposomal anchor for the covalent coupling of Fab'' fragments. We observed ... More
Quantification of uptake of liposomal carboxyfluorescein by professional phagocytes in-vitro. A flow microfluorimetric study on the J774 murine macrophage cell line.
AuthorsStevenson M, Baillie AJ, Richards RM
JournalJ Pharm Pharmacol
PubMed ID6151975
'Unilamellar egg phosphatidylcholine/cholesterol liposomes containing carboxyfluorescein were prepared by an ether injection method. The ability of cells of the J774.2 murine macrophage cell line to incorporate the liposomal fluorophore during incubation at 37 degrees C was measured by flow microfluorimetry. Liposomes incorporating additional phosphatidylserine or phosphatidic acid were taken up ... More
Hydrolysis of fluorescent pyrene-acyl esters by human pancreatic carboxylic ester hydrolase and bile salt-stimulated lipase.
AuthorsNegre-Salvayre A, Abouakil N, Lombardo D, Salvayre R
JournalLipids
PubMed ID2215086
'Fluorescent esters containing pyrenedecanoic acid (P10) or pyrenebutanoic (P4) acid (P4cholesterol, P10cholesterol, P4- and P10-containing triacylglycerols) were synthesized and used as substrates for human pancreatic carboxylic ester hydrolase and bile salt-stimulated lipase from human milk. Both enzymes were purified by immunoaffinity chromatography. All fluorescent pyrene derivatives were hydrolyzed by pancreatic ... More
Fluorescence study on the interaction of a multiple antigenic peptide from hepatitis A virus with lipid vesicles.
AuthorsOrtiz A, Cajal Y, Haro I, Reig F, Alsina MA
JournalBiopolymers
PubMed ID10775061
'The interaction of the multiple antigenic peptide MAP4VP3 with lipid membranes has been studied by spectroscopic techniques. MAP4VP3 is a multimeric peptide that corresponds to four units of the sequence 110-121 of the capsid protein VP3 of hepatitis A virus. In order to evaluate the electrostatic and hydrophobic components on ... More
Molecular mechanisms of water and solute transport across archaebacterial lipid membranes.
AuthorsMathai JC, Sprott GD, Zeidel ML
JournalJ Biol Chem
PubMed ID11373291
'Archaebacteria thrive in environments characterized by anaeobiosis, saturated salt, and both high and low extremes of temperature and pH. The bulk of their membrane lipids are polar, characterized by the archaeal structural features typified by ether linkage of the glycerol backbone to isoprenoid chains of constant length, often fully saturated, ... More
Cell death-associated translocation of plasma membrane components induced by CTL.
AuthorsKawasaki Y, Saito T, Shirota-Someya Y, Ikegami Y, Komano H, Lee MH, Froelich CJ, Shinohara N, Takayama H
JournalJ Immunol
PubMed ID10779768
'In the very early stages of target cell apoptosis induced by CTL, we found that fluorescence of labeling probes of the target plasma membrane, such as N-(3-triethylammoniumpropyl)-4-(p-dibutylaminostyryl)pyridin ium dibromide (FM1-43), was translocated into intracellular membrane structures including nuclear envelope and mitochondria. This translocation was associated with the execution of CTL-mediated ... More
Na,K-ATPase and carboxyfluorescein distinctly alter vesicle formation in vitro.
AuthorsVolet B, Lacotte D, Moosmayer M, Anner BM
JournalBiochim Biophys Acta
PubMed ID8155663
'The mechanism of vesicle formation as well as the precise reasons for their stability are not known. Thus, it is necessary to simulate the process in vitro for studying its mechanism. If phospholipids are suspended in physiological solution by means of cholate and the detergent is then removed by dialysis, ... More
Effect of average phospholipid curvature on supported bilayer formation on glass by vesicle fusion.
AuthorsHamai C, Yang T, Kataoka S, Cremer PS, Musser SM
JournalBiophys J
PubMed ID16299084
'The adsorption of large unilamellar vesicles composed of various combinations of phosphatidylcholine, phosphatidylethanolamine (PE), monomethyl PE, and dimethyl PE (PE-Me2) onto a glass surface was studied using fluorescence microscopy. The average lipid geometry within the vesicles, described mathematically by the average intrinsic curvature, C(0,ave), was methodically altered by changing the ... More
Reconstituted aquaporin 1 water channels transport CO2 across membranes.
AuthorsPrasad GV, Coury LA, Finn F, Zeidel ML
JournalJ Biol Chem
PubMed ID9837877
'Biological membranes provide selective barriers to a number of molecules and gases. However, the factors that affect permeability to gases remain unclear because of the difficulty of accurately measuring gas movements. To determine the roles of lipid composition and the aquaporin 1 (AQP1) water channel in altering CO2 flux across ... More
Lipid composition determines the effects of arbutin on the stability of membranes.
AuthorsHincha DK, Oliver AE, Crowe JH
JournalBiophys J
PubMed ID10512822
'Arbutin (hydroquinone-beta-D-glucopyranoside) is an abundant solute in the leaves of many freezing- or desiccation-tolerant plants. Its physiological role in plants, however, is not known. Here we show that arbutin protects isolated spinach (Spinacia oleracea L.) thylakoid membranes from freeze-thaw damage. During freezing of liposomes, the presence of only 20 mM ... More
Dye tracers define differential endothelial and smooth muscle coupling patterns within the arteriolar wall.
AuthorsLittle TL, Xia J, Duling BR
JournalCirc Res
PubMed ID7859395
'Dye tracers were chosen, based on net charge, chemical structure, and reactive groups, to test for the existence of and to provide novel insight into channel selectivities of junctional pathways connecting smooth muscle and endothelial cells of the arteriolar wall. Dyes were injected into individual smooth muscle or endothelial cells ... More
Weak acid-induced release of liposome-encapsulated carboxyfluorescein.
AuthorsBarbet J, Machy P, Truneh A, Leserman LD
JournalBiochim Biophys Acta
PubMed ID6326829
'Leakage of the entrapped anionic fluorophore carboxyfluorescein was used as a measure of the permeability of liposomes to several different acids. Carboxyfluorescein leakage increased with increasing buffer concentration at a given pH and depended on its chemical nature: apolar weak acids such as acetic or pyruvic acids induced fast leakage ... More
Temperature dependence of membrane ion conductance analyzed by using the amphiphilic anion 5/6-carboxyfluorescein.
AuthorsBramhall J, Hofmann J, DeGuzman R, Montestruque S, Schell R
JournalBiochemistry
PubMed ID3427008
'The rate of efflux of trapped 5/6-carboxyfluorescein from sealed lipid vesicles showed a marked dependence on (a) temperature, (b) phospholipid acyl chain composition, and (c) the nature of co-trapped counterions. When the dye was salted with sodium, at pH greater than 7, the rate of dye permeation showed a discrete ... More
Differential endocytosis of T and B lymphocyte surface molecules evaluated with antibody-bearing fluorescent liposomes containing methotrexate.
AuthorsMachy P, Barbet J, Leserman LD
JournalProc Natl Acad Sci U S A
PubMed ID7051006
'Antibody-bearing fluorescent liposomes containing methotrexate became bound to cells expressing determinants recognized by the antibody. The number of bound liposomes could be evaluated by fluorometry, and the internalization of liposomes was evaluated by the methotrexate-mediated inhibition of radio-labeled deoxyuridine incorporation. The effect of methotrexate transferred from the liposomes into the ... More
The effects of gap junction blockage on neuronal differentiation of human NTera2/clone D1 cells.
AuthorsBani-Yaghoub M, Bechberger JF, Underhill TM, Naus CC
JournalExp Neurol
PubMed ID10192774
'Gap junctions are intercellular channels which provide for the passage of small ions and molecules (MW <1200 D) among adjacent cells. The NTera2/clone D1 (NT2/D1) cells are CNS precursors which differentiate into NT2-N neurons upon treatment with retinoic acid (RA) and antiproliferative agents. In this study, the effects of gap ... More
Solubilizing effects caused by the nonionic surfactant dodecylmaltoside in phosphatidylcholine liposomes.
Authorsde la Maza A, Parra JL
JournalBiophys J
PubMed ID9083670
'The interaction of the nonionic surfactant dodecylmaltoside (DM) with phosphatidylcholine liposomes was investigated. Permeability alterations were detected as a change in 5(6)-carboxyfluorescein released from the interior of vesicles and bilayer solubilization as a decrease in the static light scattered by liposome suspensions. This surfactant showed higher capacity to saturate and ... More
Aminoglycoside antibiotics preferentially increase permeability in phosphoinositide-containing membranes: a study with carboxyfluorescein in liposomes.
AuthorsAu S, Weiner ND, Schacht J
JournalBiochim Biophys Acta
PubMed ID3038190
'The rate of release from multilamellar liposomes of the fluorescent probe carboxyfluorescein was determined as a measure of membrane permeability. Liposomes of phosphatidylcholine and different anionic phospholipids were incubated with low (1 microM) and high (3 mM) concentrations of calcium in the absence or presence of aminoglycoside antibiotics. The leakage ... More
Analysis of the feeding motor pattern in the pond snail, Lymnaea stagnalis: photoinactivation of axonally stained pattern-generating interneurons.
AuthorsKemenes G, Elliott CJ
JournalJ Neurosci
PubMed ID8283231
'We have photoinactivated identified feeding interneurons known as N1 and N2 neurons. These are pattern-generating neurons that are active in the protraction of the radula and rasping phases, respectively, of the feeding cycle of the pond snail. The N1 or N2 feeding interneurons in the buccal ganglia were filled with ... More
Anomalous driving force for renal brush border H+/OH-transport characterized by using 6-carboxyfluorescein.
AuthorsVerkman AS, Ives HE
JournalBiochemistry
PubMed ID3013286
'The pH, delta pH, and membrane potential dependences of H+/OH-permeability in renal brush border membrane vesicles (BBMV) were studied by using the entrapped pH indicator 6-carboxyfluorescein (6CF). Quantitative H+/OH-fluxes (JH) were obtained from a calibration of the fluorescence response of 6CF to intravesicular pH using vesicles prepared with varying intravesicular ... More
Liposomes as targets for granule cytolysin from cytotoxic large granular lymphocyte tumors.
AuthorsBlumenthal R, Millard PJ, Henkart MP, Reynolds CW, Henkart PA
JournalProc Natl Acad Sci U S A
PubMed ID6591203
'Purified cytoplasmic granules from rat large granular lymphocyte tumors having natural killer activity and/or antibody-dependent cell-mediated cytotoxicity induced a rapid, dose-dependent release of the water-soluble marker carboxyfluorescein from liposomes made of phosphatidylcholine. A solubilized, partially purified cytolytic preparation termed "cytolysin" from these granules showed identical properties. Marker release induced by ... More
Protein-independent lead permeation through myelin lipid liposomes.
AuthorsDíaz RS, Monreal J
JournalMol Pharmacol
PubMed ID7723737
'We have investigated the permeability of protein-free myelin lipid liposomes to inorganic lead by using the fluorescent probes fura-2, oxonol V, pyranine, and carboxyfluorescein. Inorganic lead readily crossed the lipid bilayer, as detected with fura-2, to an extent that depended on the external pH and the total nominal lead concentration ... More
Aplysia cell adhesion molecules and serotonin regulate sensory cell-motor cell interactions during early stages of synapse formation in vitro.
AuthorsZhu H, Wu F, Schacher S
JournalJ Neurosci
PubMed ID7965085
'Long-term facilitation of sensorimotor synapses of Aplysia in culture by serotonin (5-HT) is accompanied by two changes: an increase in the number of sensory cell branches and varicosities contacting the major axons of the target motor cell L7, and a downregulation of Aplysia cell adhesion molecules (apCAM) from the surface ... More
Investigation of membrane disruption in the reaction catalyzed by cholesterol oxidase.
AuthorsGhoshroy KB, Zhu W, Sampson NS
JournalBiochemistry
PubMed ID9166784
'Dye leakage experiments were undertaken to investigate the membrane disruption properties of cholesterol oxidase. Inspection of the X-ray crystal structures of cholesterol oxidase suggested that an active-site "lid" opens in order to bind substrate [Li, J., Vrielink, A., Brick, P., & Blow, D. M. (1993) Biochemistry 32, 11507-11515]. We tested ... More
The effects of pH and intraliposomal buffer strength on the rate of liposome content release and intracellular drug delivery.
AuthorsLee RJ, Wang S, Turk MJ, Low PS
JournalBiosci Rep
PubMed ID9743475
'Targeted liposomal drug formulations may enter cells by receptor-mediated endocytosis and then traffick by membrane flow into acidic intracellular compartments. In order to understand the impact of these intracellular pH changes on liposomal drug unloading, the effect of pH on the release from folate-targeted liposomes of three model compounds with ... More
Negative cooperativity exhibited by the lytic amino-terminal domain of human perforin: implications for perforin-mediated cell lysis.
AuthorsRochel N, Cowan J
JournalChem Biol
PubMed ID8807825
'BACKGROUND: Cytolytic effector cells of the immune system recognize and lyse cells that carry non-self epitopes. One mechanism of cell lysis involves release of a 67-kDa pore-forming protein, perforin. The amino-terminal domain of perforin (>/= 19 residues) can account for most of the lysis activity, by a mechanism that is ... More
Measurement of glutathione levels in intact roots of Arabidopsis.
AuthorsFricker MD, May M, Meyer AJ, Sheard N, White NS
JournalJ Microsc
PubMed ID10849194
'Levels of glutathione were measured for different cell types in roots of intact Arabidopsis seedlings after labelling with monochlorobimane to give fluorescent glutathione S-bimane (GSB) and imaging using confocal laser scanning microscopy with excitation at 442 nm. Labelling increased to a plateau in most cell types after about 15-20 min ... More
Novel fluorescein-based flow-cytometric method for detection of lipid peroxidation.
AuthorsMakrigiorgos GM, Kassis AI, Mahmood A, Bump EA, Savvides P
JournalFree Radic Biol Med
PubMed ID8958133
'The novel property of fluorescein to detect peroxyl radicals is demonstrated. On the basis of this observation, a fluorescein-based, flow-cytometric method to directly and continuously detect free radicals generated in cell membranes during lipid peroxidation has been developed. 5- and 6-Carboxyfluorescein (5-/6-CF) free in solution and fluorescein-labeled polylysine lose their ... More
The interaction of Sendai virus with negatively charged liposomes: virus-induced lysis of carboxyfluorescein-loaded small unilamellar vesicles.
AuthorsAmselem S, Loyter A, Lichtenberg D, Barenholz Y
JournalBiochim Biophys Acta
PubMed ID2996597
'The interaction of Sendai virus with small, unilamellar vesicles, lacking virus receptors and loaded with self-quenched 6-carboxyfluorescein, was studied. Sendai virions induced release of carboxyfluorescein from vesicles composed of negative charged phospholipids, despite the fact that they did not contain virus receptors. Preliminary experiments indicate that the carboxyfluorescein release is ... More
Mechanism of the cell-penetrating peptide transportan 10 permeation of lipid bilayers.
AuthorsYandek LE, Pokorny A, Florén A, Knoelke K, Langel U, Almeida PF
JournalBiophys J
PubMed ID17218466
'The mechanism of the interaction between the cell-penetrating peptide transportan 10 (tp10) and phospholipid membranes was investigated. Tp10 induces graded release of the contents of phospholipid vesicles. The kinetics of peptide association with vesicles and peptide-induced dye efflux from the vesicle lumen were examined experimentally by stopped-flow fluorescence. The experimental ... More
Differential roles of ionic, aliphatic, and aromatic residues in membrane-protein interactions: a surface plasmon resonance study on phospholipases A2.
AuthorsStahelin RV, Cho W
JournalBiochemistry
PubMed ID11294634
'The roles of cationic, aliphatic, and aromatic residues in the membrane association and dissociation of five phospholipases A(2) (PLA(2)), including Asp-49 PLA(2) from the venom of Agkistrodon piscivorus piscivorus, acidic PLA(2) from the venom of Naja naja atra, human group IIa and V PLA(2)s, and the C2 domain of cytosolic ... More
Low permeability of liposomal membranes composed of bipolar tetraether lipids from thermoacidophilic archaebacterium Sulfolobus acidocaldarius.
AuthorsKomatsu H, Chong PL
JournalBiochemistry
PubMed ID9425030
'The physical origin of the extremely high thermal stability of tetraether liposomes composed of the polar lipid fraction E (PLFE) from the thermoacidophilic archaebacterium Sulfolobus acidocaldarius has been investigated. The leakage rate of trapped 5, 6-carboxyfluorescein (5(6)CF) and the proton permeability in PLFE liposomes have been measured using fluorescence probe ... More
Liposome-mediated transfer of macromolecules into flagellated cell envelopes from bacteria.
AuthorsLelkes PI, Klein L, Marikovsky Y, Eisenbach M
JournalBiochemistry
PubMed ID6367823
'We have studied the interaction between flagellated cell envelopes from Escherichia coli and liposomes. Oligolamellar liposomes of ca. 0.45-micron diameter, composed of azolectin, phosphatidylserine, and cholesterol at a molar ratio of 7:1:2, were prepared by freezing and thawing and subsequent extrusion through polycarbonate filters. These liposomes exhibited high entrapment capacity ... More
Multiplexed capillary zone electrophoresis and micellar electrokinetic chromatography with internal standardization.
AuthorsXue G, Pang HM, Yeung ES
JournalAnal Chem
PubMed ID10424161
'Although liquid chromatography and gas chromatography are the main workhorses in the analytical laboratory, samples can only be analyzed consecutively in an instrument. In this study, capillary zone electrophoresis and micellar electrokinetic chromatography separations are performed in a 96-capillary array system with laser-induced fluorescence detection. Migration times of four kinds ... More
Endocytosis of water channels in rat kidney: cell specificity and correlation with in vivo antidiuresis.
AuthorsLencer WI, Brown D, Ausiello DA, Verkman AS
JournalAm J Physiol
PubMed ID1701969
'Vasopressin action in the renal collecting duct is believed to be mediated by the cycling of water channels in principal and, possibly, intercalated cells. We used 6-carboxyfluorescein (6-CF) or fluorescein-labeled dextran (FITC-dextran) to determine the location and water permeability of endocytic vesicles from papilla and inner stripe of Brattleboro rats ... More
Extending the applicability of carboxyfluorescein in solid-phase synthesis.
AuthorsFischer R, Mader O, Jung G, Brock R
JournalBioconjug Chem
PubMed ID12757391
'Optimized coupling protocols are presented for the efficient and automated generation of carboxyfluorescein-labeled peptides. Side products, generated when applying earlier protocols for the in situ activation of carboxyfluorescein, were eliminated by a simple procedure, yielding highly pure fluorescent peptides and minimizing postsynthesis workup. For the cost-efficient labeling of large compound ... More
Spontaneous fusion of phosphatidylcholine small unilamellar vesicles in the fluid phase.
AuthorsLentz BR, Carpenter TJ, Alford DR
JournalBiochemistry
PubMed ID3676258
'Using a high-sensitivity differential scanning microcalorimeter capable of performing cooling scans, we have examined the phase behavior of small unilamellar vesicles (SUV) as a function of time of storage above their order-disorder phase transition. Vesicles composed of dipalmitoylphosphatidylcholine (DPPC) and dimyristoylphosphatidylcholine (DMPC) were examined. Cooling scans on fresh (5-7-h postsonication) ... More
GPI-anchored influenza hemagglutinin induces hemifusion to both red blood cell and planar bilayer membranes.
AuthorsMelikyan GB, White JM, Cohen FS
JournalJ Cell Biol
PubMed ID7593189
'Under fusogenic conditions, fluorescent dye redistributed from the outer monolayer leaflet of red blood cells (RBCs) to cells expressing glycophosphatidylinositol-anchored influenza virus hemagglutinin (GPI-HA) without transfer of aqueous dye. This suggests that hemifusion, but not full fusion, occurred (Kemble, G. W., T. Danieli, and J. M. White. 1994. Cell. 76:383-391). ... More
Flow cytometric analysis of liposome-nuclei interaction: transfer and intranuclear release of carboxyfluorescein.
AuthorsPapa S, Caramelli E, Allegri G, Billi AM, Manzoli FA, Capitani S
JournalCytometry
PubMed ID3731959
'Flow cytometric analysis of the transfer of liposome-encapsulated carboxyfluorescein to isolated rat liver nuclei indicated that the fluorophore is actively taken up in this form, while negligible amounts are transferred when the dye is free in the reaction medium. The kinetic analysis of the uptake indicated a time- and dose-dependent ... More
Stimulation by target cell membrane lipid of actin polymerization and phagocytosis by Entamoeba histolytica.
AuthorsBailey GB, Day DB, Nokkaew C, Harper CC
JournalInfect Immun
PubMed ID2886434
'The identity of molecules of mammalian target cells that stimulate contact-dependent attack by Entamoeba histolytica was sought using human erythrocytes (RBC) as a model. Protein-free liposomes prepared from RBC membrane lipids stimulated the same rapid E. histolytica actin polymerization and phagocytosis as did whole target cells. Liposomes constructed from the ... More
Functional characterization of pediocin PA-1 binding to liposomes in the absence of a protein receptor and its relationship to a predicted tertiary structure.
AuthorsChen Y, Shapira R, Eisenstein M, Montville TJ
JournalAppl Environ Microbiol
PubMed ID9023932
'The physicochemical interaction of pediocin PA-1 with target membranes was characterized using lipid vesicles made from the total lipids extracted from Listeria monocytogenes. Pediocin PA-1 caused the time- and concentration-dependent release of entrapped carboxyfluorescein (CF) from the vesicles. The pediocin-induced CF efflux rates were higher under acidic conditions than under ... More
Novel fluorescence sensing methods for high throughput screening.
AuthorsLakowicz JR, Gryczynski I, Gryczynski Z
JournalJ Biomol Screen
PubMed ID10894755
'We describe two new methods of fluorescence sensing for use in high throughput screening (HTS). Modulation sensing transforms analyte-dependent intensity changes into a change in the low-frequency modulation signal. Polarization sensing transforms an intensity change into a change in polarization. Both methods are internally calibrated by using a reference film ... More
Interactions of cationic lipid vesicles with negatively charged phospholipid vesicles and biological membranes.
AuthorsStamatatos L, Leventis R, Zuckermann MJ, Silvius JR
JournalBiochemistry
PubMed ID3415963
'Lipid vesicles with a positive surface charge have been prepared by using mixtures of phosphatidylethanolamine (PE) and phosphatidylcholine (PC) together with low mole fractions of a cationic lipid analogue, 1,2-bis(oleoyloxy)-3-(trimethylammonio)propane (DOTAP). We have used measurements of vesicle aggregation, lipid mixing, contents mixing, and contents leakage to examine the interactions between ... More
Gap junctional intercellular communication contributes to hormonal responsiveness in osteoblastic networks.
Authors Vander Molen M A; Rubin C T; McLeod K J; McCauley L K; Donahue H J;
JournalJ Biol Chem
PubMed ID8647809
'To evaluate whether intercellular coupling via connexin43 gap junction channels modulates hormonal responsiveness of cells in contact, we have created osteoblastic cell lines deficient in connexin43. Osteoblastic ROS 17/2.8 cells were transfected with a plasmid containing an antisense cDNA construct to rat connexin43. Control transfection did not alter cell-to-cell coupling ... More
Immobilized liposome layers for drug delivery applications: inhibition of angiogenesis.
AuthorsVermette P, Meagher L, Gagnon E, Griesser HJ, Doillon CJ
JournalJ Control Release
PubMed ID11943397
'Liposomes were immobilized onto the surface of perfluorinated polymer tape samples and tissue culture polystyrene well-plates using a multilayer immobilization strategy. In the first step, a thin interfacial bonding layer with surface aldehyde groups was deposited from a glow discharge struck in acetaldehyde vapour. Polyethylenimine was then covalently bound onto ... More
Staphylococcal alpha-toxin increases the permeability of lipid vesicles by cholesterol- and pH-dependent assembly of oligomeric channels.
AuthorsForti S, Menestrina G
JournalEur J Biochem
PubMed ID2471641
'alpha-Toxin, a lethal hemolytic toxin secreted by Staphylococcus aureus, forms ionic channels of large size in lipid membranes. To investigate the mechanism of channel assembly we have studied the kinetics of pore formation on small unilamellar vesicles. We have used two assays of vesicle permeabilization: one is the release of ... More
Mechanism of magainin 2a induced permeabilization of phospholipid vesicles.
AuthorsGrant E, Beeler TJ, Taylor KM, Gable K, Roseman MA
JournalBiochemistry
PubMed ID1390773
'The magainins, peptide antibiotics secreted by the frog Xenopus laevis, have previously been shown to permeabilize phospholipid vesicles. To elucidate the mechanism of permeabilization, we have conducted detailed kinetic studies of magainin 2 amide (mgn2a)-induced release of 6-carboxyfluorescein from vesicles of phosphatidylserine. The results show that dye release occurs in ... More
Interaction of liver clathrin coat protein with lipid model membranes.
AuthorsSteer CJ, Klausner RD, Blumenthal R
JournalJ Biol Chem
PubMed ID7085681
'Coated vesicles were prepared from rat liver homogenates by sucrose density gradient centrifugation and the clathrin coat, dissociated by mild treatment with Tris-Cl, was characterized by sodium dodecyl sulfate gel electrophoresis. At pH 6.5 and below, the soluble clathrin preparations induced a voltage-dependent increase in ion conductance across a black ... More
Acousto-optical deflection-based laser beam scanning for fluorescence detection on multichannel electrophoretic microchips.
AuthorsHuang Z, Munro N, Hühmer AF, Landers JP
JournalAnal Chem
PubMed ID10596211
'Laser beam scanning driven by an acousto-optical deflector (AOD) is presented for multimicrochannel laser-induced fluorescence (LIF) detection during microchip-based electrophoresis. While fast laser beam scanning for LIF detection on capillary or microchannel arrays can been achieved with galvanometric scanning or a translating stage, it can also be accomplished by using ... More
The effect of general anesthetics on the proton and potassium permeabilities of liposomes.
AuthorsBarchfeld GL, Deamer DW
JournalBiochim Biophys Acta
PubMed ID2994733
'The pump-leak hypothesis of general anesthesia proposes that anesthetics act by increasing the functional proton permeability of membranes, particularly those of synaptic vesicles. Since transmembrane proton gradients are required for neurotransmitter accumulation, decay of such gradients by an uncompensated anesthetic-induced leak would result in loss of neurotransmitter from the vesicles, ... More
Lipid II is an intrinsic component of the pore induced by nisin in bacterial membranes.
AuthorsBreukink E, van Heusden HE, Vollmerhaus PJ, Swiezewska E, Brunner L, Walker S, Heck AJ, de Kruijff B
JournalJ Biol Chem
PubMed ID12663672
'The peptidoglycan layers surrounding bacterial membranes are essential for bacterial cell survival and provide an important target for antibiotics. Many antibiotics have mechanisms of action that involve binding to Lipid II, the prenyl chain-linked donor of the peptidoglycan building blocks. One of these antibiotics, the pore-forming peptide nisin uses Lipid ... More
Gene transfer from targeted liposomes to specific lymphoid cells by electroporation.
AuthorsMachy P, Lewis F, McMillan L, Jonak ZL
JournalProc Natl Acad Sci U S A
PubMed ID3186704
'Large unilamellar liposomes, coated with protein A and encapsulating the gene that confers resistance to mycophenolic acid, were used as a model system to demonstrate gene transfer into specific lymphoid cells. Protein A, which selectively recognizes mouse IgG2a antibodies, was coupled to liposomes to target them specifically to defined cell ... More
Enhanced fluorescence in indirect immunophenotyping by the use of fluorescent liposomes.
AuthorsGray AG, Morgan J, Linch DC, Huehns ER
JournalJ Immunol Methods
PubMed ID2502576
'Small unilamellar liposomes were optimised for cell phenotyping by indirect immunofluorescence. This involved selection and covalent attachment to the liposome of a polyspecific ligand for cell-bound antibody. For this purpose sheep anti-mouse antibody was preferred to protein A because of its ability to attach to cell-bound IgG1 as well as ... More
Construction and evaluation of a frequency-domain epifluorescence microscope for lifetime and anisotropy decay measurements in subcellular domains.
AuthorsVerkman AS, Armijo M, Fushimi K
JournalBiophys Chem
PubMed ID1873470
'The measurement of time-resolved fluorescence parameters in living cells provides a powerful approach to study cell structure and dynamics. An epifluorescence microscope was constructed to resolve multi-component fluorescence lifetimes and complex anisotropy decay rapidly in labile biological samples. The excitation source consisted of focused, polarized laser light modulated by an ... More
A sensitive, versatile microfluidic assay for bacterial chemotaxis.
AuthorsMao H, Cremer PS, Manson MD
JournalProc Natl Acad Sci U S A
PubMed ID12704234
'We have developed a microfluidic assay for bacterial chemotaxis in which a gradient of chemoeffectors is established inside a microchannel via diffusion between parallel streams of liquid in laminar flow. The random motility and chemotactic responses to L-aspartate, L-serine, L-leucine, and Ni(2+) of WT and chemotactic-mutant strains of Escherichia coli ... More
Fluorescent labeling of endocytic compartments.
AuthorsSwanson J
JournalMethods Cell Biol
PubMed ID2464119
Transition of a liquid crystalline phosphatidylcholine bilayer to the gel phase in a vesicle reduces the internal aqueous volume.
AuthorsLichtenberg D, Felgner PL, Thompson TE
JournalBiochim Biophys Acta
PubMed ID6895700
'The liquid crystalline to gel phase transition in phospholipid bilayers is associated with a marked reduction in the area per phospholipid molecule. Geometric considerations based on published data suggest that this decrease in molecular area is accompanied by a reduction in the internal aqueous volume trapped within a unilamellar bilayer ... More
Hydrophilic fluorescein derivatives: useful reagents for liposome immunolytic assays.
AuthorsFiechtner M, Wong M, Bieniarz C, Shipchandler MT
JournalAnal Biochem
PubMed ID2817337
'Hydrophilic derivatives of fluorescein containing hydroxyalkyl substituents were synthesized and encapsulated within liposomes. The fluorophores showed significantly more retention with time than did fluorescein, carboxyfluorescein, or calcein. Unlike calcein, the fluorophores are minimally susceptible to fluorescence quenching by Co2+. The utility of these compounds as immunodiagnostic reagents was demonstrated by ... More
Expression and localisation analysis of the wheat sucrose transporter TaSUT1 in vegetative tissues.
AuthorsAoki N, Scofield GN, Wang XD, Patrick JW, Offler CE, Furbank RT
JournalPlanta
PubMed ID15014993
'Previously we reported the isolation of three sucrose transporter genes, TaSUT1A, 1B and 1D, all expressed at high levels in the developing grains of hexaploid wheat ( Triticum aestivum L.), but also in a variety of other tissues. In order to further characterise the expression of the TaSUT1 genes in ... More
Effects of humidified and dry air on corneal endothelial cells during vitreal fluid-air exchange.
AuthorsCekiç O, Ohji M, Hayashi A, Fang XY, Kusaka S, Tano Y
JournalAm J Ophthalmol
PubMed ID12095811
'PURPOSE: To report the immediate anatomic and functional alterations in corneal endothelial cells following use of humidified air and dry air during vitreal fluid-air exchange in rabbits. DESIGN: Experimental study. METHODS: Rabbits undergoing pars plana vitrectomy and lensectomy were perfused with either dry or humidified air during fluid-air exchange for ... More
Antibody-directed targeting of liposomes to human cell lines: role of binding and internalization on growth inhibition.
AuthorsBerinstein N, Matthay KK, Papahadjopoulos D, Levy R, Sikic BI
JournalCancer Res
PubMed ID3664498
'Small unilamellar liposomes containing methotrexate or methotrexate-gamma-aspartate were conjugated to Staphylococcus aureus protein A and were thus able to bind cell-specific immunoglobulins for targeting to malignant human B- and T-cell lines. We were able to demonstrate enhanced protein A liposome uptake and growth inhibition by targeting with an anti-major histocompatibility ... More
The stability and functional properties of proteoliposomes mixed with dextran derivatives bearing hydrophobic anchor groups.
AuthorsElferink MG, de Wit JG, In 't Veld G, Reichert A, Driessen AJ, Ringsdorf H, Konings WN
JournalBiochim Biophys Acta
PubMed ID1374644
'Liposomes composed of Escherichia coli phospholipid were coated with polysaccharides bearing hydrophobic palmitoyl anchors. The effect on the stability of liposomes without or with integral membrane proteins was investigated. A high concentration of hydrophobized dextrans protected the liposomes against detergent degradation, decreased the fluidity of the membranes, prevented fusion of ... More
In vitro pore-forming activity of the lantibiotic nisin. Role of protonmotive force and lipid composition.
'Nisin is a lantibiotic produced by some strains of Lactococcus lactis subsp. lactis. The target for nisin action is the cytoplasmic membrane of Gram-positive bacteria. Nisin dissipates the membrane potential (delta psi) and induces efflux of low-molecular-mass compounds. Evidence has been presented that a delta psi is needed for nisin ... More
Polar fluorescein derivatives as improved substrate probes for flow cytoenzymological assay of cellular esterases.
AuthorsDive C, Cox H, Watson JV, Workman P
JournalMol Cell Probes
PubMed ID3173358
'Fluorescein esters are employed in assays of cell viability, membrane permeability and esterase activity. The ester most widely used, fluorescein diacetate (FDA), has the disadvantage of rapid cellular efflux of its hydrolysis product fluorescein. This is particularly problematic for flow cytoenzymology (FCE), where fluorescence is measured in individual cells allowing ... More
Membrane interactions of synthetic peptides corresponding to amphipathic helical segments of the human immunodeficiency virus type-1 envelope glycoprotein.
'The human and simian immunodeficiency virus envelope glycoproteins, which mediate virus-induced cell fusion, contain two putative amphipathic helical segments with large helical hydrophobic moments near their carboxyl-terminal ends. In an attempt to elucidate the biological role of these amphipathic helical segments, we have synthesized peptides corresponding to residues 768-788 and ... More
Use of lectins and polyethylene glycol for fusion of glycolipid-containing liposomes with eukaryotic cells.
AuthorsSzoka F, Magnusson KE, Wojcieszyn J, Hou Y, Derzko Z, Jacobson K
JournalProc Natl Acad Sci U S A
PubMed ID6940182
'Efficient fusion of phospholipid vesicles with monolayer cultures of eukaryotic cells was accomplished by attaching glycolipid-containing vesicles to the cell surface by using a lectin displaying binding for both the cell surface and the glycolipid, followed by treatment with polyethylene glycol. Fusion was inferred from the transfer of fluorescent lipid ... More
Lipoprotein lipase- and phospholipase A2-catalyzed hydrolysis of phospholipid vesicles with an encapsulated fluorescent dye. Effects of apolipoproteins.
AuthorsFugman DA, Shirai K, Jackson RL, Johnson JD
JournalBiochim Biophys Acta
PubMed ID6548158
'The self-quenching dye, 6-carboxyfluorescein, has been encapsulated into sonicated vesicles of egg phosphatidylcholine. Porcine pancreatic phospholipase A2 and bovine milk lipoprotein lipase catalyze the hydrolysis of the phosphatidylcholine resulting in the release of the encapsulated dye and a large increase in 6-carboxyfluorescein fluorescence. The fluorescence increase occurs in parallel with ... More
Comparison of two liposome fusion assays monitoring the intermixing of aqueous contents and of membrane components.
AuthorsRosenberg J, Düzgünes N, Kayalar C
JournalBiochim Biophys Acta
PubMed ID6626546
'Divalent cation-induced fusion of large unilamellar vesicles (approx. 0.1 micron diameter) made of phosphatidylserine (PS) or phosphatidylglycerol (PG) has been studied. Intermixing of aqueous contents during fusion was followed by the Tb/dipicolinic acid fluorescence assay, and intermixing of membrane components by resonance energy transfer between fluorescent lipid probes. Both assays ... More
A model for the diffusion of fluorescent probes in the septate giant axon of earthworm. Axoplasmic diffusion and junctional membrane permeability.
AuthorsBrink PR, Ramanan SV
JournalBiophys J
PubMed ID4052564
'The diffusion of the three fluorescent probes dichlorofluorescein, carboxyfluorescein, and Lucifer Yellow within the septate median giant axon of the earthworm was monitored using fluorometric methods. A diffusion model was derived that allowed computation of the apparent axoplasmic diffusion coefficient, junctional membrane permeability (septal membranes), and plasma membrane permeability for ... More
Carboxyfluorescein. A probe of the blood-ocular barriers with lower membrane permeability than fluorescein.
AuthorsGrimes PA, Stone RA, Laties AM, Li W
JournalArch Ophthalmol
PubMed ID7073583
'We have examined the permeability of the blood-ocular barriers to carboxyfluorescein, a dye similar in spectral properties but more polar than fluorescein. Octanol-buffer partition ratios of carboxyfluorescein, measured as an indication of lipid solubility, were approximately 1,000 times lower than those of fluorescein at pH values between 6.40 and 8.03. ... More
Mechanisms of delivery of liposome-encapsulated cytosine arabinoside to CV-1 cells in vitro. Fluorescence-microscopic and cytotoxicity studies.
AuthorsBrown PM, Silvius JR
JournalBiochim Biophys Acta
PubMed ID2110480
'Fluorescence microscopy and assays of the cytotoxicity of liposome-encapsulated cytosine arabinoside (araC) have been used to examine the interactions of CV-1 cells with pH-sensitive liposomes, combining phosphatidylethanolamine (PE) with oleic acid or with double-chain protonatable amphiphiles, and with pH-insensitive liposomes combining phosphatidylcholine (PC) and phosphatidylglycerol (PG). Fluorescence-microscopic observations indicate that ... More
Macromolecule entrapment in human placental microvillous membrane vesicles.
AuthorsIllsley NP, Goodman JG, Verkman AS, Davis B
JournalAnal Biochem
PubMed ID2469349
'An osmotic lysis technique was developed to induce transient permeability in human placental microvillous membrane vesicles. The degree of vesicle opening and resealing was quantitated using the fluorescent markers, 6-carboxyfluorescein and fluorescein dextran. Compared to freeze-thaw and sonication methods, hypotonic lysis was significantly more efficient, causing greater than 90% lysis ... More
Plant fructans stabilize phosphatidylcholine liposomes during freeze-drying.
AuthorsHincha DK, Hellwege EM, Heyer AG, Crowe JH
JournalEur J Biochem
PubMed ID10632723
'Fructans have been implicated as protective agents in the drought and freezing tolerance of many plant species. A direct proof of their ability to stabilize biological structures under stress conditions, however, is still lacking. Here we show that inulins (linear fructose polymers) isolated from chicory roots and dahlia tubers stabilize ... More
A fluorometric method for measurement of oxygen radical-scavenging activity of water-soluble antioxidants.
AuthorsNaguib YM
JournalAnal Biochem
PubMed ID10933861
'The relative activities of the antioxidants Trolox, ascorbic acid, uric acid, quercetin, and rutin, and the activities of total antioxidants in serum samples were determined using a fluorometric assay based on the dye 6-carboxyfluoroscein (6C-Fl) as a fluorescent indicator; 2,2''-azobis-2-amidinopropane hydrochloride (AAPH) as a peroxyl radical generator; 6-hydroxy-2,5,7, 8-tetramethyl-1-chroman-2-carboxylic acid ... More
Raman spectroscopy of synthetic antimicrobial frog peptides magainin 2a and PGLa.
AuthorsWilliams RW, Starman R, Taylor KM, Gable K, Beeler T, Zasloff M, Covell D
JournalBiochemistry
PubMed ID2350550
'Magainin and PGLa are 23- and 21-residue peptides isolated from the skin of the African clawed frog Xenopus laevis. They protect the frog from infection and exhibit a broad-spectrum antimicrobial activity in vitro. The mechanism of this activity involves the interaction of magainin with microbial membranes. We have measured the ... More
Fusion of coated vesicles with lysosomes: measurement with a fluorescence assay.
AuthorsAltstiel L, Branton D
JournalCell
PubMed ID6131746
'A fluorescence assay was developed to measure the rate of fusion of highly purified clathrin-coated vesicles isolated from bovine brain with purified lysosomes isolated from bovine kidney. Coated vesicles and stripped vesicles, prepared by removal of clathrin from coated vesicles with dilute alkaline buffer, were labeled with the nonfluorescent dye ... More