Physical studies on the membranes and lipids of plasmalogen-deficient Megasphaera elsdenii

• Published in: Chemistry and physics of lipids Vol. 55; no. 1; p. 41
• Main Authors: Kaufman, A E, Goldfine, H, Narayan, O, Gruner, S M
• Format: Journal Article
• Language: English
• Published: Ireland 01-07-1990
• Subjects: Cell Membrane - chemistry; Fluorescence Polarization; Magnetic Resonance Spectroscopy; Membrane Lipids - analysis; Plasmalogens - metabolism; Thermodynamics; Veillonellaceae - analysis; X-Ray Diffraction
• ISSN: 0009-3084
• DOI: 10.1016/0009-3084(90)90147-J

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.