Synthetic Lipid Bilayer Membranes

Henn, Fritz A.; Thompson, T. E.

doi:10.1146/annurev.bi.38.070169.001325

Cited by 94 publications

(26 citation statements)

References 33 publications

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“…These activation energy values are close to the values obtained here with animals adapted to 20~ (about 10 kcal.mol-1). These values are also similar to those obtained for water permeation through artificial lipid membranes (Hanai & Haydon, 1966 ;Henn & Thompson, 1969).…”

Section: Discussionsupporting

confidence: 88%

Water permeability and lipid composition of toad urinary bladder: The influence of temperature

1976

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The water diffusional permeability, its activation energy and the lipid composition were studied in urinary bladders from toads adapted to different temperatures. It was observed that the unidirectional water flux greatly depends on the temperature at which the experiments are performed. This dependence is greater in the animals adapted to higher temperatures. Toads adapted to cold show strong reduction in the activation energy for water diffusion permeability (from 11.4+/-1.9 kcal-mol-1 to 4.4+/-1.1kcal-mol-1) and an increase of 30% in the amount of total lipids from bladder epithelial cells. There were no significant changes in the phospholipid/cholesterol ratio, composition of the parafinic chains or protein concentration between toads adapted to both temperatures. The possibility that water translocates through the mucosal border of the toad bladder by partitioning in the polar zone and diffusioning between the hydrocarbon chains of the membrane lipids and that cold adaptation would induce a stronger "packing" of lipids in the membrane is discussed.

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Section: Discussionsupporting

confidence: 88%

Water permeability and lipid composition of toad urinary bladder: The influence of temperature

1976

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“…The breakdown voltage of the membranes was 140 to 200 mV. These parameters are typical for bimolecular, or bilayer, membranes (Mueller et al, 1962;Henn & Thompson, 1969).…”

Section: Sterol-lipid Membranes and Water Permeability 277mentioning

confidence: 87%

Water permeability of bilayer lipid membranes: Sterol-lipid interaction

Graziani

Livné

1972

J. Membrain Biol.

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Bilayer lipid membranes were generated in an aqueous medium from synthetic, egg or plant phosphatidyl choline (PC) or from plant monogalactosyl diglyceride (MG). The water permeability of the black membranes was determined by measuring the net volume flux produced by a NaCl gradient. The osmotic permeability coefficient,P os, was markedly affected by the number of double bonds in the fatty acid conjugates of the lipids: the greater the degree of unsaturation, the higher the value ofP os. The temperature dependence ofP os of the lipid membranes was studied over a range of 29 to 40°C. The experimental activation energy,E a , estimated from the linear plots of log (P os)versus 1/T, was significantly higher for MG membranes (17 kcal/mole) than for the various PC membranes (11 to 13 kcal/mole), probably owing to hydrogen bonding between MG and water molecules. In comparison with PC membranes, the membranes generated from PC and cholesterol (1∶1 molar ratio) had lowerP os but similarE a values. Likewise, either stigmasterol or β-sitosterol decreasedP os of MG membranes, whileE a was not affected by the sterols. MG-cholesterol membranes were specifically characterized by a unique value ofE a (-36 kcal/mole) thus indicating temperature dependent structural changes.

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“…A number of results indicate slight or no selectivity by membranes formed fromuncharged lipids (Mueller et al, 1962;Lev & Buzinsky, 1967;Andreoli, Bangham & Tosteson, 1967;Hopfer, Lehninger & Lenarz, 1970) and cation selectivity for membranes formed from negatively charged lipids Hopfer et al, 1970). Henn, on the other hand, found only slight cation selectivity in membranes formed from the negatively charged phosphatidyl serine (Henn & Thompson, 1969) while Miyamoto and Thompson (1961) observed a small degree of selectivity for cations in membranes formed from the neutral lipid phosphatidyl choline. and Hopfer et al (1969) have pointed out that the surface charge must influence the permeability of these membranes, although they did not consider in detail the mechanism by which this influence is exerted.…”

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confidence: 99%

Comparison of double layer potentials in lipid monolayers and lipid bilayer membranes

MacDonald

Bangham

1972

J. Membrain Biol.

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It is shown that the Gouy-Chapman double layer analysis adequately describes the variation of the surface potential of monolayers of acidic natural lipids over a wide range of surface charge density and salt concentration. It is also shown that the potential which initially appears when an electrolyte gradient is rapidly imposed across a bilayer membrane is due to a difference in the double layer potentials on the two sides of the membrane. This conclusion follows from the fact that the observed bilayer potentials arise much more rapidly than can be accounted for by charge migration across the membrane and from the observation that the bilayer membrane concentration potentials, when measured immediately after establishment of a gradient, are equal to the surface potential change observed when the subphase concentration of a monolayer of the same lipid is changed by an amount equal to the gradient across the bilayer. The bilayer potential and monolayer potential changes, so measured, agree in a number of different electrolyte solutions over a wide range of electrolyte concentrations and surface charge densities. Because of this agreement and the applicability of the Gouy theory to monolayers, initial bilayer potentials may be calculated if the composition of the mixture used to form the membrane is known, provided that the pK's and areas of such components are available. In the absence of this information, membrane potentials may be calculated from electrophoretic data on the membrane lipid mixture; the conditions under which the latter approach is possible have been determined. The experimental results indicate that the composition of monolyers and bilayers spread from the same lipid mixture in decane are very similar, that the composition of the two types of film closely resembles the composition of the solution used to generate them, and that bilayer membranes are close-packed. The evidence further indicates that if any hydrocarbon solvent remains in these bilayers, it must be so situated that it contributes little, if anything, to the surface area. The steady state potential in the bilayer membrane system is frequently not identical with the initial potential which supports the hypothesis that in many cases only a fraction of the electrical conductance of unmodified membranes is caused by the ions which constitute the bulk electrolyte. An expression for the relationship between diffusion and double layer potentials has been derived which shows that, in the absence of any intrinsic selectivity of the hydrocarbon region of the membrane for hydrogen, hydroxyl, or impurity, the two potentials should be identical.

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Synthetic Lipid Bilayer Membranes

Cited by 94 publications

References 33 publications

Water permeability and lipid composition of toad urinary bladder: The influence of temperature

Water permeability and lipid composition of toad urinary bladder: The influence of temperature

Water permeability of bilayer lipid membranes: Sterol-lipid interaction

Comparison of double layer potentials in lipid monolayers and lipid bilayer membranes

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