Simultaneous visualization of nucleous (To-Pro3), mitochondria (GFP) and microtubules (Alexa594) in a rat liver cell line (C9). The image was obtained in a Radiance 2000 BioRad confocal on a Zeiss Axiovert S100 TV microscope . (Image contributed by Prof. J. M. Cuezva. Centro Biología Molecular Severo Ochoa. Madrid. Spain.).