In order to detect the viruses in the hot spring water, researchers treated the viruses with a dye that makes their DNA glow with fluoresce and allows the organisms to be seen with a microscope designed to view this fluorescence. In the image on the left, the viruses appear as small dots compared to the two larger microbial cells. This imaging method is used during virus purification to check for the complete removal of bacterial and other cells from the virus preparation. The shapes of the viruses can be seen using an electron microscope (right). The viruses in the hot springs assume a variety of different physical shapes (rods, filaments, spheres, tailed icosahedrons), some of which are only seen in hot springs. Credit: Thomas Schoenfeld, Lucigen Corp.