Temperature dependence of dipalmitoyl phosphatidylcholine monolayer stability

Goerke, Jon; Gonzales, Jonathan

doi:10.1152/jappl.1981.51.5.1108

Cited by 97 publications

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“…Since natural and lipid extract surfactants adsorb very rapidly, the other surfactant components appear critical for adsorption of DPPC into the surface film. The ability of surfactant films to attain low surface tension approaching 0 mN/m during compression (8,(34)(35)(36) has long been attributed to the formation of a monolayer highly enriched in DPPC [as reviewed in refs. (3-6, 33, 37, 38)].…”

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confidence: 99%

Lipid compositional analysis of pulmonary surfactant monolayers and monolayer-associated reservoirs

Possmayer

2003

Journal of Lipid Research

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Pulmonary surfactant is a lipid:protein complex containing dipalmitoyl-phosphatidylcholine (DPPC) as the major component. Recent studies indicate adsorbed surfactant films consist of a surface monolayer and a monolayerassociated reservoir. It has been hypothesized that the monolayer and its functionally contiguous reservoir may be enriched in DPPC relative to bulk phase surfactant. We investigated the compositional relationship between the monolayer and its reservoir using paper-supported wet bridges to transfer films from adsorbing dishes to clean surfaces on spreading dishes. Spreading films appear to form monolayers in the spreading dishes. We employed bovine lipid ex- It is generally agreed that the alveolar surface is covered by a continuous thin layer of water that supports a surface active film of pulmonary surfactant (1, 2) [for review see (3-7)]. Through its ability to reduce the surface tension of this air-water interface, pulmonary surfactant stabilizes the terminal air spaces. Considerable evidence has accumulated indicating that surfactant films are composed of more than a single monolayer. Pattle (8) first proposed that the surfactant film overlying the alveolar lining layer consists of a monomolecular layer and underlying material that serves as a reservoir. Using electron microscopy, Weibel and Gil (9) observed the presence of lamellar layers of phospholipids with three to six repeating distances of 38-51 Å on the alveolar epithelial surface of rat lungs. Studies by Manabe (2) and, more recently, Bastacky et al. (1) using scanning electron microscopic studies indicate that the alveolar lining layer is continuous and its surface contains many lipidic structures. In vitro studies involving surface films adsorbed from surfactant dispersions have also provided evidence indicating the surface monolayer is accompanied by a functional continuous reservoir (10-13). Surfactant reservoirs that can provide phospholipids to the air-water interface during surface area expansion can also be created during film compression (14)(15)(16)(17) [as reviewed in refs. (18, 19)].Pulmonary surfactant consists of ‫ف‬ 90% lipids and ‫ف‬ 10% protein. The phospholipid composition of bovine pulmonary surfactant, which is representative of mammalian species, consists of ‫ف‬ 80% total phosphatidylcholines (PCs), 10-15% phosphatidylglycerol (PG), 2-3% each of phosphatidylethanolamine, phosphatidylinositol, and sphingomyelin, and 1-2% lyso-bis -phosphatidic acid (20). Dipalmitoylphosphatidylcholine (DPPC) and 1-palmitoyl-2-oleoyl-phosphatidylcholine (POPC) are major molecular species, while dipalmitoylphosphatidylglycerol (DPPG) and 1-palmitoyl-2-oleoyl-phosphatidylglycerol (POPG) are present at significant levels (20)(21)(22). Bovine pulmonary surfactant also contains ‫ف‬ 4% neutral lipids, of which ‫ف‬ 90% is cholesterol. Pulmonary surfactant proteins (SPs) consist of two small hydrophobic proteins, SP-B and SP-C, and two hydrophilic complex glycoproteins, .

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confidence: 99%

Lipid compositional analysis of pulmonary surfactant monolayers and monolayer-associated reservoirs

Possmayer

2003

Journal of Lipid Research

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“…DPPC monolayers were present in liquid condensed phase and exhibited smooth surface topography on AFM imaging. The DPPC molecules have parallel and compactly packed hydrocarbon chains which endow upon them the property to form tightly packed films [35]. Addition of cord factor changed the physical state of DPPC film from liquid condensed to liquid expanded phase and altered the surface topography with appearance of clusters and aggregates.…”

Section: Discussionmentioning

confidence: 99%

Molecular interactions of cord factor with dipalmitoylphosphatidylcholine monolayers: Implications for lung surfactant dysfunction in pulmonary tuberculosis

Chimote

Banerjee

2008

Colloids and Surfaces B: Biointerfaces

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“…The absence of barriers eliminates a potential site at which collapse might nucleate, as well as a site for the leakage that inevitably occurs at high π in troughs. 9 The bubble can also attain faster rates of interfacial compression which allow the films to reach high π that are frequently difficult to achieve using Langmuir troughs. A captive bubble therefore allows a more in-depth study of the effects of π on rates of collapse.…”

Section: Methodsmentioning

confidence: 99%

“…Previous studies have focused on rates of area-decay at a single, constant π 2-4 and on the effects of increasing π. 2,[5][6][7][8] Although, according to those studies, rates of collapse should increase with greater Δπ = π − π e , phosphatidylcholine (PC) films show an unexpected variation, observed first with measurements in a Langmuir trough 9 and more recently on a captive bubble. 10,11 For at least some PC monolayers in the fluid liquid-expanded (LE) phase, rates of collapse first increase with greater Δπ but then slow ( Figure 1).…”

Section: Introductionmentioning

confidence: 94%

Transformation Diagrams for the Collapse of a Phospholipid Monolayer

2004

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The kinetics of phase transitions in three-dimensional bulk materials are commonly presented in transformation diagrams. Time-temperature transformation (TTT) and continuous-coolingtransformation (CCT) diagrams plot the time required to transform specific fractions of the material to the new phase by cooling below a transition temperature. Transformation occurs isothermally for the TTT diagrams and during continuous cooling through a range of temperatures for CCT curves. Here we present analogous transformation diagrams for two-dimensional monolayers, which collapse at the equilibrium spreading pressure (π e ) to form a three-dimensional bulk phase. Time-surface pressure-transformation (TπT) diagrams give the time required for specific fractions of the film to collapse when surface pressure is constant, and continuouscompression-transformation diagrams give the same information when surface pressure varies continuously. The diagrams, constructed here from previously reported data for 1-palmitoyl-2-oleoyl phosphatidylcholine, provide insights into the behavior of the films. The TπT diagrams successfully predict the existence and approximate magnitude of a threshold rate for compressing the films to high surface pressures above π e and the approximate shape of isotherms obtained with different rates of interfacial compression. The diagrams also caution that the behavior of mixed monolayers, explained previously in terms of compositional changes, can instead result from collapse that varies with surface pressure. Finally, the similarity between the shapes of the TTT and TπT diagrams, with the time for transformation passing through a minimum and then increasing as the systems deviate further from equilibrium, suggests that analogous mechanisms determine the behavior of both systems.

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Temperature dependence of dipalmitoyl phosphatidylcholine monolayer stability

Cited by 97 publications

References 0 publications

Lipid compositional analysis of pulmonary surfactant monolayers and monolayer-associated reservoirs

Lipid compositional analysis of pulmonary surfactant monolayers and monolayer-associated reservoirs

Molecular interactions of cord factor with dipalmitoylphosphatidylcholine monolayers: Implications for lung surfactant dysfunction in pulmonary tuberculosis

Transformation Diagrams for the Collapse of a Phospholipid Monolayer

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