Aspects of the protein and the lipid composition of myelinoid Marchi-positive bodies from mammalian spinal cord.
The fraction floating on 0.32 M sucrose was isolated from normal mammalian spinal cord and analyzed with regard to protein and lipid composition. Comparisons were made with the myelin fraction isolated from the same spinal cord. A close relationship between the two fractions was indicated by a similar protein banding on SDS-polyacrylamide gel electrophoresis. The relative amounts of various proteins however were different and some high molecular weight proteins appeared unique to the floating fraction. The phospho- and galactolipid patterns, as revealed by thin-layer chromatography, were similar in the floating and the myelin fractions. The proportion of hydrophobic lipids, such as sterols and isoprenyl derivatives, was higher in the floating fraction. Bands co-migrating with cholesterol esters were detected only in the floating fraction from guinea pigs. Marchi-positive material of possible paranodal origin is enriched in the floating fraction. The present findings of a biochemical composition of the floating fraction closely resembling that of myelin is in line with the view that myelin turnover includes a step of degradation localized to the paranodal regions.
Corneliuson
O
O
Department of Anatomy, Gothenburg University, Sweden.
Berthold
C H
CH
Persson
H
H
Fredman
P
P
D000818:Animals; D002415:Cats; D002855:Chromatography, Thin Layer; D004591:Electrophoresis, Polyacrylamide Gel; D006168:Guinea Pigs; D008055:Lipids / Q000032:analysis*; D009185:Myelin Proteins / Q000032:analysis*; D009186:Myelin Sheath / Q000032:analysis* / Q000648:ultrastructure; D010743:Phospholipids / Q000032:analysis; D011817:Rabbits; D051381:Rats; D013116:Spinal Cord / Q000032:analysis*; D013194:Staining and Labeling
D008055:Lipids; D009185:Myelin Proteins; D010743:Phospholipids