Sphingomyelin Favors. Precipitation of Negatively Charged Liposomes in 1 mM Ca2

  title={Sphingomyelin Favors. Precipitation of Negatively Charged Liposomes in 1 mM Ca2},
  author={Norma L. Yoss and M. Mahfouz and Hongling Diao and Fred A. Kummerow},
  journal={Journal of Liposome Research},
AbstractEarlier studies showed that calcium and sphingomyelin increase in aortic intimal tissue with age. Liposomes having different aortic phospholipid concentrations were prepared to ascertain if the increase in calcium might have arisen from increased permeability to calcium. None of these liposomes were permeable to calcium, however, liposomes that contained sphingomyelin and carried an excess negative charge imparted by dicetylphosphate aggregatively precipitated out of suspension in 1 mM… 
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Failure of phosphatidic acid to translocate Ca2+ across phosphatidylcholine membranes
It is reported that PA is not able to demonstrate facilitation by PA of Ca2+ fluxes across liposomal membranes, which does not seem compatible with known features of biological membranes or the properties of ionophores known to translocate ions across membranes.
Interaction of cholesterol with synthetic sphingomyelin derivatives in mixed monolayers.
It was observed that replacement of the 3-hydroxy group of sphingomyelin with a hydrogen atom or its substitution with a methoxy or ethoxy group did not affect the ability of cholesterol to condense the molecular packing in monolayers, while the condensing effect of cholesterol on derivatives of N-stearoyl-SPMs was significantly larger.
Structure and dynamics of the phosphatidylcholine and the phosphatidylethanolamine head group in L‐M fibroblasts as studied by deuterium nuclear magnetic resonance.
Mouse fibroblast L‐M cells were grown in tissue culture medium containing selectively deuterated choline or ethanolamine leading to a selective deuteration of these phospholipid head groups, and the phosphocholine head group conformation appeared to sense an electrically neutral environment in spite of the fact that L‐ M cell membranes contain 10‐20% negatively charged lipids.
A general method, employing arsenazo III in liposomes, for study of calcium ionophores: results with A23187 and prostaglandins.
It is demonstrated not only that liposomes containing arsenazo III may be employed in a sensitive asssay for agents that translocate divalent cations, but that a water-soluble derivative of a naturally occurring fatty acid, PGBx, is a potent ionophore.
Headgroup interactions in mixed phospholipid bilayers.
  • F. Sixl, A. Watts
  • Chemistry
    Proceedings of the National Academy of Sciences of the United States of America
  • 1983
The large changes in the deuterium quadrupole splittings for the zwitterionic lipids after addition of a charged lipid suggest that either a strong perturbation in the hydrogen bonding occurs or changes take place in the water structure at the membrane surface, or possibly both.
A general method for the introduction of enzymes, by means of immunoglobulin-coated liposomes, into lysosomes of deficient cells.
Uptake at 30 degrees of aggregated IgM-coated liposomes containing trapped horseradish peroxidase exceeded that of free enzyme of 100-fold, and was more efficient than uptake of horser Somalia peroxIDase presented in uncoatedliposomes or in liposome coated with native IgM.