title: Structure of membrane holes in osmotic and saponin hemolysis.
abstract: Serial section electron microscopy of hemolysing erythrocytes (fixed at 12 s after the onset of osmotic hemolysis) revealed long slits and holes in the membrane, extending to around 1 microm in length. Many but not all of the slits and holes (about 100-1000 A wide) were confluent with one another. Ferritin and colloidal gold (added after fixation) only permeated those cells containing membrane defects. No such large holes or slits were seen in saponin-treated erythrocytes, and the membrane was highly invaginated, giving the ghost a scalloped outline. Freeze-etch electron microscopy of saponin-treated membranes revealed 40-50 A-wide pits in the extracellular surface of the membrane. If these pits represent regions from which cholesterol was extracted, then cholesterol is uniformly distributed over the entire erythrocyte membrane.
mesh_terms: D000447:Aldehydes; D002462:Cell Membrane / Q000032:analysis / Q000187:drug effects; D002463:Cell Membrane Permeability; D002784:Cholesterol / Q000302:isolation & purification; D004912:Erythrocytes / Q000166:cytology* / Q000187:drug effects; D005293:Ferritins / Q000302:isolation & purification; D005613:Freeze Etching; D006046:Gold / Q000302:isolation & purification; D006461:Hemolysis / Q000187:drug effects*; D006651:Histocytochemistry; D006652:Histological Techniques; D006801:Humans; D008854:Microscopy, Electron; D009996:Osmotic Fragility; D012503:Saponins / Q000494:pharmacology*
chemical_list: D000447:Aldehydes; D012503:Saponins; D006046:Gold; D005293:Ferritins; D002784:Cholesterol