Fig. 6

Nuclear dynamics related to cell division processes. Acridine orange (AO) fluorescence (a, b, c, e, f) micrographs of PEG-treated NIHs cells. In a and b, the punctuate red fluorescence of acidic vesicles after use of dilute AO solution is shown; in this staining condition, nuclei are marked with a weak green fluorescence. The arrows in a and b indicate trinucleated cells in which the distribution of aggregates of red puncta allows us to deduce the positioning of the Golgi area that appears to be mainly in the center of the cell in a (arrowhead) or more dispersed in aggregates in the cytoplasm in the cell in b (arrowheads). In the insert in a, tripolar mitosis is shown. In c, e, and f, AO staining, performed according to a standard protocol (see Methods section), allowed us to observe green nuclear DNA and red cytoplasmic RNA fluorescence. In the hexanuclear 24c cell in c, the arrows indicate areas of cytoplasm discontinuity; the arrowhead indicates a micronucleus. In e and f, chromatin internuclear bridges are visible after cytokinesis process completion; arrowheads in e indicate micronuclei. In d, Hoechst 33,342 fluorescence in a microscopic field with irregular tripolar mitosis (arrow), in the insert, a trinucleated cell with single nuclei synchronized in prophase is shown. Scale bars in a, b, c, and f: 10 µm, in d and e: 5 µm