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Phospholipid-cholesterol bilayers under osmotic stress

Sparr, Emma LU ; Hallin, L; Markova, N and Wennerström, Håkan LU (2002) In Biophysical Journal 83(4). p.2015-2025
Abstract
Isothermal (27degreesC) phase behavior of dimyristoyl phosphatidyl choline-cholesterol mixtures at various Osmotic pressures and cholesterol contents was investigated by means of isothermal sorption microcalorimetry and H-2-nuclear magnetic resonance. The calorimetric method allows for simultaneous measurement of the partial molar enthalpy and the chemical potential (the osmotic pressure) of water, thus providing an almost complete thermodynamic description of the sorption process. From the experimental results, the Pi(osm) - X-chol and the ternary composition phase diagrams are constructed. We note that there are strong similarities between the Pi(osm) - X-chol phase diagram and the previously reported T - X-chol phase diagram at excess... (More)
Isothermal (27degreesC) phase behavior of dimyristoyl phosphatidyl choline-cholesterol mixtures at various Osmotic pressures and cholesterol contents was investigated by means of isothermal sorption microcalorimetry and H-2-nuclear magnetic resonance. The calorimetric method allows for simultaneous measurement of the partial molar enthalpy and the chemical potential (the osmotic pressure) of water, thus providing an almost complete thermodynamic description of the sorption process. From the experimental results, the Pi(osm) - X-chol and the ternary composition phase diagrams are constructed. We note that there are strong similarities between the Pi(osm) - X-chol phase diagram and the previously reported T - X-chol phase diagram at excess water. At high cholesterol contents a single liquid ordered (L-alpha(o)) phase is present over the whole range of water contents, implying that this phase has a remarkable stability not only at decreasing temperature but also at increasing osmotic pressure. At low cholesterol contents, the microcalorimetric experiments confirm the extraordinary property of cholesterol not to cause any substantial melting point depression. One important conclusion in the present study is that the P-beta phase can dissolve cholesterol more readily than the L-beta phase and that the addition of cholesterol induces the P-beta phase. Finally, the putative P-beta - L-alpha(o) periodic modulated structure is discussed. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Biophysical Journal
volume
83
issue
4
pages
2015 - 2025
publisher
Cell Press
external identifiers
  • pmid:12324420
  • wos:000178572500024
  • scopus:0036787585
ISSN
1542-0086
language
English
LU publication?
yes
id
4c6e4254-214e-4086-8589-26714c4df134 (old id 325784)
alternative location
http://www.biophysj.org/cgi/content/abstract/83/4/2015
date added to LUP
2007-11-14 13:31:59
date last changed
2017-05-21 03:30:19
@article{4c6e4254-214e-4086-8589-26714c4df134,
  abstract     = {Isothermal (27degreesC) phase behavior of dimyristoyl phosphatidyl choline-cholesterol mixtures at various Osmotic pressures and cholesterol contents was investigated by means of isothermal sorption microcalorimetry and H-2-nuclear magnetic resonance. The calorimetric method allows for simultaneous measurement of the partial molar enthalpy and the chemical potential (the osmotic pressure) of water, thus providing an almost complete thermodynamic description of the sorption process. From the experimental results, the Pi(osm) - X-chol and the ternary composition phase diagrams are constructed. We note that there are strong similarities between the Pi(osm) - X-chol phase diagram and the previously reported T - X-chol phase diagram at excess water. At high cholesterol contents a single liquid ordered (L-alpha(o)) phase is present over the whole range of water contents, implying that this phase has a remarkable stability not only at decreasing temperature but also at increasing osmotic pressure. At low cholesterol contents, the microcalorimetric experiments confirm the extraordinary property of cholesterol not to cause any substantial melting point depression. One important conclusion in the present study is that the P-beta phase can dissolve cholesterol more readily than the L-beta phase and that the addition of cholesterol induces the P-beta phase. Finally, the putative P-beta - L-alpha(o) periodic modulated structure is discussed.},
  author       = {Sparr, Emma and Hallin, L and Markova, N and Wennerström, Håkan},
  issn         = {1542-0086},
  language     = {eng},
  number       = {4},
  pages        = {2015--2025},
  publisher    = {Cell Press},
  series       = {Biophysical Journal},
  title        = {Phospholipid-cholesterol bilayers under osmotic stress},
  volume       = {83},
  year         = {2002},
}