Details of the vimentin intermediate filament network in a culture of PtK1 kidney epithelial cells (presented above) were visualized by treating the fixed and permeabilized culture with mouse anti-vimentin primary antibodies followed by goat anti-mouse secondary antibodies (IgG) conjugated to Texas Red-X. Cell nuclei were counterstained with SYTOX Green, a high-affinity nucleic acid probe. Images were recorded with a 60x oil immersion objective using a zoom factor of 1.5 and sequential scanning with the 488-nanometer spectral line of an argon-ion laser and the 543-nanometer line from a green helium-neon laser. During the processing stage, individual image channels were pseudocolored with RGB values corresponding to each of the fluorophore emission spectral profiles.