The second main area of research is centered around the influence of oxygen deprivation on P. aeruginosa virulence. During infection of deeper tissue or the lung of cystic fibrosis patients for example, P. aeruginosa is exposed to low oxygen tensions. However, the effect of hypoxic and anaerobic conditions on virulence traits of P. aeruginosa is not well understood. In particular, we focus on proteins whose secretion is stimulated under anoxic conditions. We identified several proteins with predicted enzymatic activity and aim to characterize their activity and role in virulence. In another project we study the mechanisms underlying the oxygen- and c-di-GMP-dependent production of alginate, an exopolysaccharide that provides protection against host immune defenses and antibiotics.