The culture of GeLu fibroblast cells shown in this confocal image was labeled for mitochondria with MitoTracker Orange CMTMRos (pseudocolored red), a derivative of tetramethylrosamine. The cells were also treated with the green-fluorescent nuclear and chromosome counterstain SYTOX Green. Images were recorded with a 60x oil immersion objective using a zoom factor of 5.0 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 unless otherwise noted above.