Cover photograph (Copyright © 2006, American Society for Microbiology. All Rights Reserved.): Confocal micrograph of Caenorhabditis elegans nematodes after ingesting GFP-expressing Pseudomonas aeruginosa. P. aeruginosa is localized to the intestine of the large nematode soon after feeding (left); however, the bacteria have disseminated from the gut in the three dead smaller nematodes (right). (Photo courtesy of K. P. Rumbaugh and J. A. Shaber.) (See related article on page 5135.)