ScienceDaily (Dec. 16, 2008) — The redox-active pigments responsible for the blue-green stain of the mucus that clogs the lungs of children and adults with cystic fibrosis (CF) are primarily signaling molecules that allow large clusters of the opportunistic infection agent, Pseudomonas aeruginosa, to organize themselves into structured communities, report Massachusetts Institute of Technology geobiologists at American Society for Cell Biology (ASCB) 48th Annual Meeting, Dec. 13-17, 2008 in San Francisco.