Journal of Okayama Medical Association
Published by Okayama Medical Association

Full-text articles are available 3 years after publication.


奥 欽也 岡山大学医学部細菌学教室
Thumnail 92_749.pdf 3.22 MB
The ultrastructure of the phospholipid micells (Phosphatidylglycerol: PG, cardiolipin: CL and lysylphosphatidylglycerol: L-PG) from S. aureus were examined by negative staining and freeze-fracture to elucidate the role of each phospholipid in staphylococcal cell membrane. The width of lipid bilayer of each phospholipid was: PG: 40A, CL: 58A and L-PG: 65A, respectively, indicating that the hydration of each lipids was different. Ca(2+) caused the fusion of cardiolipin micell followed by hexagonal-cylindrical comformation. Ca(2+) seemed to give "rigidity" to the cardiolipin bilayer. Mg(2+) modified the cardiolipin lamella causing random-ripple form. Mg(2+) gave "fluidity" to the micellar structure. PG and L-PG were less affected by Ca(2+) or Mg(2+). Conversion of PG to CL was enhanced when S. aureus was exposed to stress condition or when the cell lost the wall. Molar ratio of PG/CL was 5/2 in normal condition, while 2/5 under stress. This adaptational changes of the lipid composition in the membrane may well correlate with the characteristics of cardiolipin micellar structure.
S. aureus
Ultrastructure of phospholipid micell
Calcium effect on phospholipid