Cover photograph (Copyright © 2005, American Society for Microbiology. All Rights Reserved.): Toluene catabolic plasmid pWW0 carries genes (rulAB genes) encoding an error-prone DNA polymerase Pol V homologue which confers resistance to UV irradiation on Pseudomonas putida. The picture shows colony formation of rulAB-carrying P. putida cells irradiated with UV-C at 50 J/m² and incubated 9 h on solid medium. Bacteria were stained in situ with a LIVE/DEAD kit and visualized by epifluorescent microscopy (magnification, ×100). Green cells are live, while red cells are dead. (See related article on page 5203).