FITC Staining in C. elegans

1. A stock dye solution containing 20 mg/ml 5-fluorescein isothiocyanate in dimethylformamide can be stored at -20°C indefinitely.
2. 50 µl of this stock solution is then mixed with 200 µl of M9 buffer and applied evenly to the surface of a 10 ml NGM plate preseeded with a lawn of E. coli.
3. After 2 hr to allow the dye to diffuse into the agar, (final concentration 0.1 mg/ml), live animals are transferred to the plate.
4. After staining for 2 hr to overnight, the animals are transferred to a plate devoid of the dye for at least 10 min to remove free FITC from the intestine before viewing under the microscope.