About the Cover: Swarming of the bacterium Pseudomonas aeruginosa is impacted by exposure to the antibiotic tobramycin (added via a 10-mm diameter filter disc, left), which includes increased and spatially distinct production of Pseudomonas quinolone signal (PQS) and alkyl hydroxyquinoline (AQNO) subclasses of alkyl quinolones as analyzed using secondary ion mass spectrometry (SIMS).