Intrinsic electric fields and membrane bending

Doulah, F. A.; Coakley, W. Terence; Tilley, Drew C.

doi:10.1007/bf01858252

Cited by 14 publications

(13 citation statements)

References 25 publications

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“…was decreased with decreasing chloride concentration in order to maintain constant volume (Doulah et al, 1984).…”

Section: Journal Of Biological Physics Volume 12 1984mentioning

confidence: 99%

“…The fragmentation of cells heated in suspension, in pyrex glass microcapillaries 5 cm long at 0.50C/s, was video recorded as previously described (Doulah et al, 1984).…”

Section: Heating Of Cells and Observation Of Fragmentationmentioning

confidence: 99%

“…The proportion of heated cells fragmenting by membrane externalization at the cell rim or internalization at the cell dimple, together with the average number (~ of waves per cell rim, varies in a manner consistent with a dependence of cell fragmentation on transmembrane potential and on the membrane surface potentials (Doulah et al, 1984).…”

Section: Introductionmentioning

confidence: 97%

“…The sensitivity of the fragmentation pattern of heated erythrocytes to surface charge depletion (Coakley and Deeley, 1980;Doulah et al, 1984) suggested that the system might provide a sensitive index of the influence of extracellular divalent cations on the fragmentation pattern and hence on the induced stress in the erythrocyte membrane.…”

Section: Introductionmentioning

confidence: 99%

“…Our earlier studies of heated cell fragmentation were carried out on cells suspended in monovalent electrolytes (Coakley and Deeley, 1980;Deeley and Coakley, 1983;Doulah et al, 1984).…”

Section: Introductionmentioning

confidence: 99%

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Divalent cation effects on membrane bending in heated erythrocytes

Coakley

Doulah

1984

J Biol Phys

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ABSTRACT:The thermal fragmentation of human erythroeytes involves either surface wave growth and membrane externalization at the cell rim or membrane internalization at the cell dimple.In symmetrical monovalent electrolytes an increase in membrane internalization at the cell dimple correlates with the decrease in zeta potential arising from surface charge (sialic acid residue) depletion.The influence of divalent cations on thermal fragmentation is examined in this work.The erythrocyte zeta potential decreased when divalent cations replaced some Na + in the cell-suspending phase.The incidence of membrane internalization increased in rank order Ca 2+ > Ba 2+ > Mg ~+ ~ Sr 2+. Calcium continued to influence the thermal fragmentation of cells highly depleted of sialic acid, suggesting that the ion also interacted with membrane sites other than sialic acid.The divalent cation influence on cell fragmentation was shown to be greater than that due to zeta potential decrease alone.This conclusion was supported by the observation that the divalent cation-induced changes in zeta potential showed much less cation specificity than did the changes induced in the thermal fragmentation pattern. The result implies that the specificity of the divalent cation effects was due to interactions within the erythrocyte shear layer.The possibility that the interaction is with membrane lipids is examined.

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“…was decreased with decreasing chloride concentration in order to maintain constant volume (Doulah et al, 1984).…”

Section: Journal Of Biological Physics Volume 12 1984mentioning

confidence: 99%

“…The fragmentation of cells heated in suspension, in pyrex glass microcapillaries 5 cm long at 0.50C/s, was video recorded as previously described (Doulah et al, 1984).…”

Section: Heating Of Cells and Observation Of Fragmentationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

“…Our earlier studies of heated cell fragmentation were carried out on cells suspended in monovalent electrolytes (Coakley and Deeley, 1980;Deeley and Coakley, 1983;Doulah et al, 1984).…”

Section: Introductionmentioning

confidence: 99%

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Divalent cation effects on membrane bending in heated erythrocytes

Coakley

Doulah

1984

J Biol Phys

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Interfacial stability

Coakley

Gallez

1990

Springer Series in Biophysics

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The human erythrocyte membrane skeleton may be an ionic gel

1986

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In the first paper in this series (Stokke et al. Eur Biophys J 1986, 13:203-218) we developed the general theory of the mechanochemical properties and the elastic free energy of the protein gel--lipid bilayer membrane model. Here we report on an extensive numerical analysis of the human erythrocyte shapes and shape transformations predicted by this new cell membrane model. We have calculated the total elastic free energy of deformation of four different cell shape classes: disc-shaped cells, cup-shaped cells, crenated cells, and cells with membrane invaginations. We find that which of these shape classes is favoured depends strongly on the spectrin gel osmotic tension, IIGu, and the surface tensions, IIEu and IIPu, of the extracellular and protoplasmic halves of the membrane lipid bilayer, respectively. For constant ratio IIEu/IIPu greater than O large negative or positive values of IIGu favour respectively the crenated and invaginated cell shape classes. For small absolute values of IIGu, IIEu, and IIPu, biconcave or cup-shaped cells are the stable ones. Our numerical analysis shows that the higher the membrane skeleton compressibility is, the smaller are the values of IIGu needed to induce cell shape transformation. We find that the stable and metastable shapes of discocytes and stomatocytes generally depend both on the shape of the stressfree membrane skeleton and the membrane skeleton compressibility.

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Intrinsic electric fields and membrane bending

Abstract: ABSTRACT:The fragmentation of human erythrocytes heated in a range of ionic environments has been examined by video microscopy.

Cited by 14 publications

References 25 publications

Divalent cation effects on membrane bending in heated erythrocytes

Divalent cation effects on membrane bending in heated erythrocytes

Interfacial stability

The human erythrocyte membrane skeleton may be an ionic gel

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