Physical studies on the membranes and lipids of plasmalogen-deficient Megasphaera elsdenii.
Membrane fluidity and thermotropic phase behavior in the wild-type and plasmalogen-deficient strains of Megasphaera elsdenii have been studied by means of diphenylhexatiene steady state fluorescence anisotropy in isolated membranes, and by 31P-NMR and X-ray diffraction of the isolated phospholipids. Compared to the wild-type plasmalogen content of greater than 75%, plasmalogen-deficient strains had less than 5% plasmalogen, consisting largely of phosphatidylethanolamine and phosphatidylserine. Steady state fluorescence anisotropy measurements yielded an order parameter which was 6% lower in the plasmalogen-deficient membranes from 10 degrees to 40 degrees C, indicating higher membrane lipid mobilities. Both 31P-NMR and X-ray diffraction revealed the formation of a hexagonal phase in the lipids from the wild-type strain starting above 30 degrees C. In general the transition was not complete by 80 degrees C. In contrast, phospholipids from plasmalogen-deficient strains appeared to form a relatively stable lamellar phase.
Department of Microbiology, University of Pennsylvania School of Medicine, Philadelphia 19104-6076.
A E
AE
Kaufman
H
H
Goldfine
O
O
Narayan
S M
SM
Gruner
D002462:Cell Membrane / Q000737:chemistry; D005454:Fluorescence Polarization; D009682:Magnetic Resonance Spectroscopy; D008563:Membrane Lipids / Q000032:analysis*; D010955:Plasmalogens / Q000378:metabolism*; D013816:Thermodynamics; D045854:Veillonellaceae / Q000032:analysis*; D014961:X-Ray Diffraction
D008563:Membrane Lipids; D010955:Plasmalogens