Interaction of liposomes with black lipid membranes

Pohl, G.; Stark, G.; Trissl, H.‐W.

doi:10.1016/0005-2736(73)90214-9

Cited by 23 publications

(5 citation statements)

References 5 publications

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“…Fusion of vesicles to planar bilayer membranes, on the other hand, has presented until now its own drawbacks. Previously reported attempts to study the fusion of phospholipid vesicles to planar membranes have relied on monitoring the incorporation into the planar membrane of some membraneassociated marker from the vesicular membrane such as phospholipids (Cohen and Moronne, 1976), antibiotics (Moore, 1976), and fluorescent probes (Pohl et al, 1973). Nonfusion exchange of marker, however, can also lead to its transfer into the planar membrane.…”

Section: Introductionmentioning

confidence: 99%

Fusion of phospholipid vesicles with planar phospholipid bilayer membranes. I. Discharge of vesicular contents across the planar membrane.

Zimmerberg

Cohen

Finkelstein

1980

The Journal of General Physiology

131

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Multilamellar phospholipid vesicles are introduced into the as 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-I lamellar vesicle should be discharged into the opposite trans compartment, where it would appear as a discernible fluorescent particle. Thus, fusion events can be assayed by counting the number of fluorescent particles appearing in the trans compartment. In the absence of divalent cation, fusion does not occur, even after vesicles have been in the cis compartment for 40 min. When CaCI2 is introduced into the cis compartment to a concentration of -->20 mM, fusion occurs within the next 20 min; it generally ceases thereafter because of vesicle aggregation in the cis compartment. With approximately 3 • l0 s vesicles/cm 3 in the cis compartment, about 25-50 fusion events occur following CaCl2 addition. The discharge of vesicular contents across the planar membrane is the most convincing evidence of vesicle-membrane fusion and serves as a model for that ubiquitous biological phenomenon--exocytosis.

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Section: Introductionmentioning

confidence: 99%

Fusion of phospholipid vesicles with planar phospholipid bilayer membranes. I. Discharge of vesicular contents across the planar membrane.

Zimmerberg

Cohen

Finkelstein

1980

The Journal of General Physiology

131

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“…Photocurrents across phospholipid bilayers doped with magnesium octaethylporphyrin (MgOEP) have been observed by serveral workers Mauzerall, 1972a, b, 1974;Mauzerall and Hong, 1975;Hong, 1976;Pohl et al, 1973;Lutz et al, 1974). The underlying photoprocess is the excitation of the ground-state porphyrin (P) to an excited state, probably the triplet, pT, which would be considerably longer lived than the excited singlet, P* (Hopf and Whitten, 1975):…”

Section: Introductionmentioning

confidence: 99%

“…1 V vs. NHE. In the presence of an electron acceptor (ferricyanide Mauzerall, 1972a,b, 1974;Mauzerall and Hong, 1975;Hong, 1976] or oxygen [Pohl et al, 1973;Lutz et al, 1974]) the triplet will be oxidized:…”

Section: Introductionmentioning

confidence: 99%

Photoinitiated mediated transport of H3O+ and/or OH- across glycerol monooleate bilayers doped with magnesium octaethylporphyrin

Young¹,

Feldberg²

1979

Biophysical Journal

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“…Papahadjopoulos et al (1974b), Prestegard and Fellmeth (1974), and Kantor and Prestegard (1975) have provided additional evidence in favor of fusion. Membrane fusion has also been proposed to account for the transfer of proteins (Drachev et al, 1974) and fluorescent probes (Pohl et al, 1973) from liposomes to planar bilayers. However, much of the evidence in favor of a fusion mechanism is indirect and can just as reasonably be interpreted in terms of simple molecular exchange of the type described by Pagano and Huang (1975).…”

mentioning

confidence: 99%

Phospholipid exchange between bilayer membrane vesicles

Martin¹,

MacDonald²

1976

Biochemistry

173

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The turbidity of lipid vesicles, freshly prepared by sonicating purified dimyristoyllecithin (DML) in dilute KCl solutions, was measured as a function of time at various temperatures. A sharp maximum in the rate of increase of turbidity is found just above the crystal:liquid-crystal phase transition temperature (Tm). The initial rate of turbidity increase is first order with respect to DML concentration. Electron and light microscopy reveal large vesicles which are not present before incubation or after incubation at temperatures far from the Tm. When temperature, rather than time, is the independent variable, a sharp drop in turbidity is seen at the Tm. The magnitude of this drop and the temperature at which it occurs were used to measure the rate of lipid transfer between vesicles composed of different lipids. A mixture of DML vesicles and dipalmitoyllecithin (DPL) vesicles exhibits sharp drops in turbidity at 24 and 41 degrees, the corresponding Tm's. With time, the magnitude of the transition at 24 degrees decreases while that which was originally at 41 degrees moves to lower temperatures and increases in magnitude. At equilibrium there is a single transition at 32.5 degrees characteristic of vesicles composed of equimolar DPL and DML. The rate at which equilibrium is approached increases at around 24 degrees and again around 41 degrees. These observations indicate that vesicles are in equilibrium with monomolecular lipid, the concentration of the latter being higher the shorter the lipid acyl group or the smaller the vesicle. DML molecules are therefore lost from small vesicles to large vesicles (DML system) or lost from DML vesicles to DML-DPL vesicles (mixed system). When DML vesicles containing a few percent brain gangliosides were studied, different behavior was observed; the initial rate of increase of turbidity becomes second order in lipid concentration, and the rate constant increases with increasing concentrations of KCl. The kinetic order, coupled with the fact that electrolyte reduces intervesicle electrostatic repulsion, argues that in this situation the mechanism of vesicle growth requires vesicle collision.

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Interaction of liposomes with black lipid membranes

Cited by 23 publications

References 5 publications

Fusion of phospholipid vesicles with planar phospholipid bilayer membranes. I. Discharge of vesicular contents across the planar membrane.

Fusion of phospholipid vesicles with planar phospholipid bilayer membranes. I. Discharge of vesicular contents across the planar membrane.

Photoinitiated mediated transport of H3O+ and/or OH- across glycerol monooleate bilayers doped with magnesium octaethylporphyrin

Phospholipid exchange between bilayer membrane vesicles

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