Use of fluorescent probes in the study of phospholipid–sterol bilayers

Wharton, Steve; Martinez, S G De; Green, C

doi:10.1042/bj1910785

Cited by 10 publications

(5 citation statements)

References 39 publications

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“…These effects may be rationalized by assuming phase separation of the bilayer components into cholesterol-rich and cholesterol-poor regions either laterally (Shimshick & McConnell, 1973) or trans-versely (Huang et al, 1974;de Kruijff, 1976) and preferential partitioning of the DPH into one of these phases, giving rise, at high enough labeling ratios, to concentrations of DPH for which appreciable inter-DPH ("self-") transfer can occur, thus leading to an enhanced donor-acceptor transfer efficiency. This hypothesis is at variance with the conclusion drawn from studies on lateral energy transfer between DPH and fluorescent sterol analogues in dimyristoyllecithin and EL vesicles that no segregation of sterols occurs in such systems in the liquid-crystalline state (Wharton et al, 1980). An explanation of the discrepancy may lie in lack of consideration of orientational effects in that study.…”

Section: Discussionmentioning

confidence: 73%

“…Fluorescence quenching and resonance energy transfer methods have been used to investigate the distribution of fluorophores in both the lateral [e.g., see Fung & Stryer (1978), Wharton et al (1980), and Holowka & Baird (1983a)] and transverse planes of the lipid bilayer. In the latter application, a series of n-(9-anthroyloxy) fatty acids synthesized to position the fluorophore at graded depths within the lipid bilayer has been examined (Haigh et al, 1979;Eisinger & Flores, 1983).…”

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confidence: 99%

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Transverse location of the fluorescent probe 1,6-diphenyl-1,3,5-hexatriene in model lipid bilayer membrane systems by resonance excitation energy transfer

Davenport¹,

Dale²,

Bisby³

et al. 1985

Biochemistry

184

110

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A fluorescent phospholipid derivative, the fluoresceinthiocarbamyl adduct of a natural phosphatidylethanolamine, has been synthesized and incorporated into sonicated single-bilayer vesicles of egg lecithin and dipalmitoyllecithin. The surface location of this probe has been confirmed by using extrinsic fluorescence quenching studies together with steady-state emission anisotropy measurements. Electronic excitation energy transfer between 1,6-diphenyl-1,3,5-hexatriene incorporated within the hydrophobic core of the bilayer and the novel derivative has been investigated to estimate the depth within the bilayer at which the former is located. Efficiencies have been measured for two different phospholipids, egg lecithin and dipalmitoyllecithin, in the latter case both above and below the phospholipid phase transition, with and without added cholesterol. The observed dependence of the transfer efficiency on the acceptor concentration was compared with that calculated according to Förster theory applied to random two-dimensional distributions of donor and acceptor molecules in parallel planes for various interplanar separations, taking into account orientational effects. The Förster R0 of about 45 A for this donor-acceptor pair is particularly well suited to such studies since it is of the order of the width of the bilayer. The experiments showed that energy-transfer spectroscopy can provide useful quantitative information as to the transverse location of diphenylhexatriene in homogeneous phospholipid bilayers and may also reflect lateral partitioning of donor or of both donor and acceptor into different phases in systems exhibiting phase separations.

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Section: Discussionmentioning

confidence: 73%

mentioning

confidence: 99%

Transverse location of the fluorescent probe 1,6-diphenyl-1,3,5-hexatriene in model lipid bilayer membrane systems by resonance excitation energy transfer

Davenport¹,

Dale²,

Bisby³

et al. 1985

Biochemistry

184

110

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“…Additionally, it is known that the incorporation of Chol into liposomes makes them more rigid (30,37). However, the presence of Chol in liposomes has also been associated with fluorescence quenching of molecules within the bilayer (38–40). It is known that the presence of Chol affects the microfluidity of the bilayer and the level of exposure to water of hydrophobic molecules embedded in the bilayer (41).…”

Section: Resultsmentioning

confidence: 99%

Association of Acenaphthoporphyrins with Liposomes for the Photodynamic Treatment of Leishmaniasis

Gardner

Taylor

Cedeño

et al. 2010

Photochem & Photobiology

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Acenaphthoporphyrins are potential photosensitizers for photodynamic therapy, but their hydrophobicity limits their potential. Liposomes have been widely investigated as delivery vehicles that can transport hydrophobic drugs in biological systems. Here we study the association of acenaphthoporphyrins with liposomes made up of dimyristoyl phosphatidylcholine (DMPC), and to liposomes made up of a mixture of DMPC, cholesterol (Chol) and distearoyl phosphatidylglycerol (DSPG) in a 2:1:0.8 molar ratio to evaluate how liposome composition affects association constants. In liposomes consisting only of DMPC, the smaller monoacenaphthoporphyrin had the largest association constant of 5.5 x 10(4) m(-1) while the larger adj-diacenaphthoporphyrin and opp-diacenaphthoporphyrin (ODP) had smaller association constants at 1.8 x 10(4) and 1.5 x 10(4) m(-1), respectively. The addition of liposomal Chol and DSPG has little effect on the magnitudes of the association constants. Polarization studies show that the acenaphthoporphyrins are driven far into the lipid bilayer to minimize polar-nonpolar interactions. Confocal microscopy confirms that the DMPC liposomes transport the porphyrins into promastigotes of Leishmania tarentolae. The compounds associated with DMPC:Chol:DSPG liposomes are effective in vitro against axenic and intracellular amastigotes of the pathogenic Leishmania panamensis. The effectiveness of the compounds is enhanced upon exposure of cultures to visible light.

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“…Complete haemolysis was taken as the value obtained upon diluting the cells or microvesicles with distilled water. Lipid extraction and determination of phospholipid and cholesterol were as previously described (Wharton et al, 1980). Individual classes of phospholipid were separated by t.l.c.…”

Section: Methodsmentioning

confidence: 99%

Lipid organization in erythrocyte membrane microvesicles

Scott¹,

Pendlebury²,

Green³

1984

Biochemical Journal

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The aminophospholipids of microvesicles released from human erythrocytes on storage or prepared from erythrocyte ghosts by shearing under pressure are susceptible to the action of 2,4,6-trinitrobenzenesulphonic acid. The aminophospholipids of the former vesicles are also susceptible to attack by phospholipase A2. Under the same conditions, the aminophospholipids of erythrocytes undergo little reaction. This suggests that the phospholipids in microvesicle membranes are more randomly distributed than those in erythrocyte membranes. Measurements have also been made of the ability of filipin to react with the cholesterol of sealed and unsealed erythrocyte ghosts and of microvesicles prepared from them. From the initial rates of reaction, it was concluded that there is no preferential transfer of cholesterol molecules from one side of the bilayer to the other during the formation of the microvesicles.

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Use of fluorescent probes in the study of phospholipid–sterol bilayers

Cited by 10 publications

References 39 publications

Transverse location of the fluorescent probe 1,6-diphenyl-1,3,5-hexatriene in model lipid bilayer membrane systems by resonance excitation energy transfer

Transverse location of the fluorescent probe 1,6-diphenyl-1,3,5-hexatriene in model lipid bilayer membrane systems by resonance excitation energy transfer

Association of Acenaphthoporphyrins with Liposomes for the Photodynamic Treatment of Leishmaniasis

Lipid organization in erythrocyte membrane microvesicles

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