Reduction of nucleolar size in reaggregated Dictyostelium cells

The ultra-structure of the nucleolus in Dictyostelium discoideum cells was studied by electron microscopy. Large nucleoli on the periphery of the nucleus in cells of the multi-cellular pseudoplasmodium (slug) were maintained during long migration. Disaggregation of the slug cells induced a reduction in the size of the large nucleoli. The size of the reduced nucleoli in the reaggregated cells were maintained during the long migration and culmination of reconstructed slug. The electron density of the cytoplasm clearly distinguishes the prespore from the prestalk region, and it takes about 6 h for the complete recovery of cell-to-cell contact after reaggregation.