Under the microscope, an E. coli cell lights up like a fireball. Each bright dot marks a surface protein that tells the bacteria to move toward or away from nearby food and toxins. Using a new imaging technique, researchers can map the proteins one at a time and combine them into a single image. This lets them study patterns within and among protein clusters in bacterial cells, which don't have nuclei or organelles like plant and animal cells. Seeing how the proteins arrange themselves will help researchers better understand how cell signaling works. Courtesy of UC Berkeley biophysicists Derek Greenfield and Ann McEvoy.

Featured in the August 19, 2009, issue of Biomedical Beat.