[The growth dynamics of nucleoli and their silver stainability in the cell cycle of ESK cells in a monolayer culture].

The cell cycle progression of individual pig embryo kidney (PK) cells was followed by time-lapse microphotography. Evidence has been presented that every detachment of cells from the substrate for subculturing leads to nearly a twofold decrease in the average number of nucleoli per nucleus. However, this number is progressively increased with every generation of flattened cells on the substrate. It appears that these nucleolar alterations reflect the nucleolar fusion in the suspended cells and the disruption of fused nucleoli during mitosis in the cells on the substrate. The configuration of nucleoli within the nuclei of cells on the substrate remains very stable through interphase, despite the movements of the nucleus, as a whole, in the plane of monolayer. The nucleoli grow through all the stages of interphase. The increase in the nucleolar size is highly coordinated with the increase in nuclear size and in the silver stainability of the nucleoli.