1. DAPI is frequently used for staining nuclei.
2. Wash and harvest cells.
3. Fix cells. For example, mammalian cells can be fixed in
buffered paraformaldehyde. Yeast cells may be fixed in 70% ethanol
(and sonicate for 5 seconds).
4. Wash cells with PBS.
5. Stain cells in 0.1-1 mg/ml of DAPI in PBS
for 20 minutes to 2 hours.
6. Wash cells with PBS.
7. Mount, seal with nail polish and keep in dark before viewing under
a fluorescence microscope.