Nuclear envelope - plasma membrane - compaction domain in malaria parasites.

A novel compaction domain between the nuclear envelope and the plasma membrane is observed in intraerythrocytic Plasmodium knowlesi and Plasmodium chabaudi. The plasma membrane and the two nuclear membranes stick very closely together thus forming a heptalamina domain. This has an outer diameter of 14.3 +/- 1.1 nm and can be as long as 2/um. Fracture faces in this region appear to be devoid of the typical membrane-intercalating-particles. This compaction domain occurs only in ring-stages and early to mid trophozoites, but never in schizonts.