Document Detail


Relating domain size distribution to line tension and molecular dipole density in model cytoplasmic myelin lipid monolayers.
MedLine Citation:
PMID:  21606329     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
We fit the size distribution of liquid-ordered (L(o)) domains measured from fluorescence images of model cytoplasmic myelin monolayers with an equilibrium thermodynamic expression that includes the competing effects of line tension, λ, dipole density difference, Δm, and the mixing entropy. From these fits, we extract the line tension, λ, and dipole density difference, Δm, between the L(o) and liquid-disordered (L(d)) phases. Both λ and Δm decrease with increasing surface pressure, , although λ/Δm(2) remains roughly constant as the monolayer approaches the miscibility surface pressure. As a result, the mean domain size changed little with surface pressure, although the polydispersity increased significantly. The most probable domain radius was significantly smaller than that predicted by the energy alone, showing that the mixing entropy promotes a greater number of smaller domains. Our results also explain why domain shapes are stable; at equilibrium, only a small fraction of the domains are large enough to undergo theoretically predicted shape fluctuations. Monolayers based on the composition of myelin from animals with experimental allergic encephalomyelitis had slightly lower values of λ and Δm, and a higher area fraction of domains, than control monolayers at all . While it is premature to generalize these results to myelin bilayers, our results show that the domain distribution in myelin may be an equilibrium effect and that subtle changes in surface pressure and composition can alter the distribution of material in the monolayer, which will likely also alter the interactions between monolayers important to the adhesion of the myelin sheath.
Authors:
Dong Woog Lee; Younjin Min; Prajnaparamitra Dhar; Arun Ramachandran; Jacob N Israelachvili; Joseph A Zasadzinski
Related Documents :
9576019 - Lung diffusion estimated by oxygen and carbon monoxide.
22029489 - Evaluating the risk of eye injuries: intraocular pressure during high speed projectile ...
12721469 - Effects of pressure pulsation on oxygen transfer rate measured by sulfite method.
10579269 - Platelet-activating factor and arachidonic acid metabolites mediate tumor necrosis fact...
21762559 - Airway pressure release ventilation: what do we know?
19384199 - Glutaraldehyde-polymerized bovine hemoglobin and phosphodiesterase-5 inhibition.
15631279 - Automated office and home phone-transmitted blood pressure recordings in uncontrolled h...
6241889 - Aortic pressure, substrate utilization and protein synthesis.
9150959 - Vascular responses to acute vibration in the fingers of normal subjects.
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural     Date:  2011-05-23
Journal Detail:
Title:  Proceedings of the National Academy of Sciences of the United States of America     Volume:  108     ISSN:  1091-6490     ISO Abbreviation:  Proc. Natl. Acad. Sci. U.S.A.     Publication Date:  2011 Jun 
Date Detail:
Created Date:  2011-06-09     Completed Date:  2011-08-26     Revised Date:  2014-09-18    
Medline Journal Info:
Nlm Unique ID:  7505876     Medline TA:  Proc Natl Acad Sci U S A     Country:  United States    
Other Details:
Languages:  eng     Pagination:  9425-30     Citation Subset:  IM    
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Descriptor/Qualifier:
Algorithms
Animals
Cytoplasm / chemistry,  metabolism
Entropy
Humans
Hydrophobic and Hydrophilic Interactions
Image Processing, Computer-Assisted
Kinetics
Lipid Bilayers / chemistry*,  metabolism
Membrane Lipids / chemistry*,  metabolism
Membrane Microdomains / chemistry*,  metabolism
Membrane Proteins / chemistry,  metabolism
Microscopy, Fluorescence / methods
Models, Chemical
Models, Molecular
Myelin Sheath / chemistry*,  metabolism
Phosphatidylcholines / chemistry,  metabolism
Phosphatidylethanolamines / chemistry,  metabolism
Phosphatidylserines / chemistry,  metabolism
Sphingomyelins / chemistry,  metabolism
Grant Support
ID/Acronym/Agency:
GM076709/GM/NIGMS NIH HHS; HL051177/HL/NHLBI NIH HHS; R01 HL051177/HL/NHLBI NIH HHS
Chemical
Reg. No./Substance:
0/Lipid Bilayers; 0/Membrane Lipids; 0/Membrane Proteins; 0/Phosphatidylcholines; 0/Phosphatidylethanolamines; 0/Phosphatidylserines; 0/Sphingomyelins; 39382-08-6/phosphatidylethanolamine
Comments/Corrections

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


Previous Document:  Human telomerase model shows the role of the TEN domain in advancing the double helix for the next p...
Next Document:  Photosynthetic electron partitioning between [FeFe]-hydrogenase and ferredoxin:NADP+-oxidoreductase ...