In order to label the intermediate filaments in the log phase adherent FoLu culture illustrated above, the fixed and permeabilized cells were blocked and treated with mouse anti-vimentin (porcine eye lens) primary antibodies followed by goat anti-mouse secondary antibodies (IgG) conjugated to Alexa Fluor 488. Cell nuclei were counterstained with the red-absorbing dye TO-PRO-3. Images were recorded with a 60x oil immersion objective using a zoom factor of 2.5 and sequential scanning with the 488-nanometer spectral line of an argon-ion laser and the 633-nanometer line of a red helium-neon laser. During the processing stage, individual image channels were pseudocolored with RGB values corresponding to each of the fluorophore emission spectral profiles.