Cover photograph (Copyright © 2006, American Society for Microbiology. All Rights Reserved.): Fluorescence micrograph of a colony of the PCB degrader Comamonas testosteroni strain TK102 stained with Oregon Green 488 carboxylic acid and propidium iodide. Live cells emit green fluorescence, and dead cells emit red fluorescence. Some TK102 cells in the colony that were incubated with vapor-phase biphenyl exhibited filamentous morphology and eventually died. Magnification, ×400. (See related article in the July 2006 issue: vol. 72, pages 5037-5042.)