
Cover image: Confocal micrograph of Crenothrix polyspora detected by 16S rRNA-targeted fluorescence in situ hybridization. This uncultured filamentous bacterium is known for mass development in drinking water systems. Cultivation-independent molecular approaches reveal that C. polyspora is a novel methane-oxidizing bacterium. See the article by Stoecker et al. on pages 2363–2367.