Fluorescent Microscopy: Dyes which fluoresce different colors under microscope-generated UV light can be attached to different target materials in biological specimens making them easily visible. In this digital image, laboratory-cultured bovine endothelial cells have been treated with a green-fluorescing dye which attaches to the actin filaments of the cells' extensive cytoskeleton system. The lighter oval areas indicate the locations of cell nuclei surrounded by heavy concentrations of actin filaments.
