Influence of calcium, cholesterol, and unsaturation on lecithin monolayers

Shah, Dinesh O.; Schulman, J. H.

doi:10.1016/s0022-2275(20)40140-3

Cited by 263 publications

(43 citation statements)

References 12 publications

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“…Cholesterol can condense DPPC as well as unsaturated PC monolayers (17,32). This effect has been interpreted as that of cholesterol occupying cavities existing between fatty acyl chains of adjacent DPPC molecules (17). As a result, cholesterol cannot be squeezed out readily from mixed monolayers through repeated compression.…”

Section: Discussionmentioning

confidence: 99%

“…Although the same surfactant components were observed in spread and adsorbed monolayers using a simple surfactant model consisting of DPPC and SP-C (16), it is not known whether all the components of pulmonary surfactant are adsorbed into the monolayer or how the non-DPPC components are eliminated during compression. Several studies (17)(18)(19)(20) have demonstrated that cholesterol cannot be squeezed out readily from mixed monolayers through repeated compression. Previously using [ 14 C]cholesterol we have shown that cholesterol could be readily transported to the surface in bLES(chol) dispersions but not by itself, and SP-A suppressed the transport of cholesterol to the surface (19).…”

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confidence: 99%

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Interaction of pulmonary surfactant protein A with dipalmitoylphosphatidylcholine and cholesterol at the air/water interface

Possmayer

1998

Journal of Lipid Research

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Interaction of pulmonary surfactant protein A (SP-A) with pure and binary mixed dipalmitoylphosphatidylcholine (DPPC) and cholesterol (3.5 wt%) at the air/saline, 1.5 m m CaCl 2 interface was investigated using a rhomboid surface balance at 37 Њ C. Surface tension-area isotherms were measured to access the surface active properties of the monolayers. The organization of DPPC and cholesterol in DPPC and DPPC/cholesterol mixed monolayers with or without SP-A at equilibrium surface tension ( Ϸ 23 mN/N) was revealed by autoradiographs of Langmuir-Blodgett (L-B) films deposited from [ 14 C]DPPC or [ 14 C]cholesterol-labeled monolayers. The results showed that SP-A can interact with the polar head groups of DPPC monolayers and aggregate DPPC molecules. SP-A decreased the surface area reduction required for DPPC monolayers to achieve near zero surface tension from 30 to 25% of the area at equilibrium. SP-A also reduced the collapse surface tension of pure cholesterol from 27 to 23 mN/m. DPPC and cholesterol formed homogeneous mixed monolayers when both were dissolved in the spreading solvent prior to spreading, while separate cholesterol-rich domains appeared when DPPC and cholesterol were spread successively. Cholesterol resisted squeeze-out from either mixed monolayer through compression. Although SP-A could not promote the squeeze-out of cholesterol from homogeneous mixed monolayers, it facilitated that of cholesterol domains especially when SP-A had first interacted with DPPC. These results indicate that pulmonary surfactant protein A facilitates the squeeze-out of cholesterol domains from mixed monolayers by condensing DPPC and limiting lateral interactions of DPPC with cholesterol domains.-Yu, S-H., and F. Possmayer. Interaction of pulmonary surfactant protein A with dipalmitoylphosphatidylcholine and cholesterol at the air/water interface.

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Interaction of pulmonary surfactant protein A with dipalmitoylphosphatidylcholine and cholesterol at the air/water interface

Possmayer

1998

Journal of Lipid Research

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“…we still do not know enough about the molecular architecture of a functional biomembrane to be certain of the precise nature of the primary sites of reaction between agent and membrane component during cell lysis. The recent excellent work by Shah and Schulman (1967) has established the properties of mixed cholesterol-lecithin monolayers and suggested that the possession of the sterol would increase the flexibility of the membrane. To what extent this type of monolayer model would increase or decrease the accessibility of cholesterol in the erythrocyte membrane cannot be said at the present time.…”

Section: Physical Chemistry Of Hemolysismentioning

confidence: 99%

Lytic Agents, Cell Permeability, and Monolayer Penetrability

Saltón

1968

The Journal of General Physiology

144

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Cell lysis induced by lytic agents is the terminal phase of a series of events leading to membrane disorganization and breadkdown with the release of cellular macromolecules. Permeability changes following exposure to lytic systems may range from selective effects on ion fluxes to gross membrane damage and cell leakage. Lysis can be conceived as an interfacial phenomenon, and the action of surface-active agents on erythrocytes has provided a model in which to investigate relationships between hemolysis and chemical structure, ionic charge, surface tension lowering, and ability to penetrate monolayers of membrane lipid components. Evidence suggests that lysis follows the attainment of surface pressures exceeding a "critical collapse" level and could involve membrane cholesterol or phospholipid. Similarities of chemical composition of membranes from various cell types could account for lytic responses observed on interaction with surface-active agents. Cell membranes usually contain about 20-30 % lipid and 50-75 % protein. One or two major phospholipids are present in all cell membranes, but sterols are not detectable in bacterial membranes other than those of the Mycoplasma group. The rigid cell wall in bacteria has an important bearing on their response to treatment with lytic agents. Removal of the wall renders the protoplast membrane sensitive to rapid lysis with surfactants. Isolated membranes of erythrocytes and bacteria are rapidly dissociated by surface-active agents. Products of dissociation of bacterial membranes have uniform behavior in the ultracentrifuge (sedimentation coefficients 2-3S). Dissociation of membrane proteins from lipids and the isolation and characterization of these proteins will provide a basis for investigating the specificity of interaction of lytic agents with biomembranes.The lysis or clearing of cell suspensions by lytic agents and lytic systems is the terminal phase of what has long been regarded as an interfacial phenomenon and has been the subject of intensive investigations for many decades. Much valuable information about the nature of cell surfaces had been deduced from these studies, at a time when the cellular membranes and walls were not amenable to the techniques of isolation now commonly employed. With the tremendous growth of our knowledge of the chemistry and structural organization of cell surfaces during the past 10 years, we are in a position to 227 s

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“…It is of interest to note that the influence of these steroids on A(AV) appears to be unique, in that other compounds which have similar fused ring structures do not give the same type of results with insoluble lipid films. For example, cholesterol in mixed lipid films usually changes the surface potential approximately in proportion to its mole fraction in the surface film (31), while for the soluble steroids A (AV) appears to be independent of the surface concentration of the steroid. Another compound for comparison is the steroid alkaloid veratrine; at a concentration of 2 X 10 -5 M, veratrine will produce values of A(AV) which, unlike the steroid hormones, depend on the chemical nature of the surface film (N. L. Gershfeld, unpublished results).…”

Section: A Characteristics Of Steroid-lipid Monolayer Interactionsmentioning

confidence: 99%

The Interaction between Steroid Hormones and Lipid Monolayers on Water

Gershfeld

Muramatsu

1971

The Journal of General Physiology

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The interaction of progesterone, testosterone, androsterone, and etiocholanolone with insoluble lipid films (cholesterol and saturated hydrocarbons containing either alcohol, ester, acetamide, phosphate, amine, or carboxyl groups) was studied. In addition to surface pressure and surface potential measurements of the surface films, radioactive tracers were used to measure the concentration of adsorbed steroid in the lipid films. In general, steroids form mixed films with the insoluble lipid films. Compression of the insoluble lipid films to their most condensed state leads to complete ejection of adsorbed steroid from the surface in all cases except with the amine, for which a small amount of steroid is still retained in the surface. Interactions between the steroids and insoluble lipids are primarily due to van der Waals or dispersion forces; there were no significant contributions from dipole-dipole interactions (except possibly with the amine). Specific interactions between cholesterol and the soluble steroids were not observed. Evidence suggests that low steroid concentrations influence structure of lipid films by altering the hydration layer in the surface film. In contrast to a specific site of action, it is proposed that steroid hormones initiate structural changes in a variety of biological sites; this model of steroid action is consistent with the ubiquity of many steroid hormones.

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Influence of calcium, cholesterol, and unsaturation on lecithin monolayers

Cited by 263 publications

References 12 publications

Interaction of pulmonary surfactant protein A with dipalmitoylphosphatidylcholine and cholesterol at the air/water interface

Interaction of pulmonary surfactant protein A with dipalmitoylphosphatidylcholine and cholesterol at the air/water interface

Lytic Agents, Cell Permeability, and Monolayer Penetrability

The Interaction between Steroid Hormones and Lipid Monolayers on Water

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