The HeLa carcinoma cell culture featured in the digital image above was transfected with an EGFP-peroxisomal targeting signal 1 (PTS1) fusion protein and stained with MitoTracker Red CMXRos. These fluorescent probes target the peroxisomes and intracellular microtubule network, respectively. Images were recorded with a 60x oil immersion objective using a zoom factor of 3.5 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.