Cytoplasmic induction of changes in the ultrastructure of the Acetabularia nucleus and perinuclear cytoplasm.

The ultrasturcture of the cell nucleus and perinuclear cytoplasm in Acetabularia is quite different in young and old cells. When a nucleus of an old cell was implanted into the cytoplasm of a young cell the nucleus assumed the morphology typical of a young cell within less than 10 days. The cytoplasm of an old cell was able to induce the reverse change in an implanted nucleus from a young cell. This cytoplasmic induction of nuclear ageing appeared to proceed more rapidly than rejuvenation.