When bacteria grow in multicellular communities called biofilms, they benefit from increased protection in the face of environmental stress. However, the biofilm mode of growth presents challenges of its own, including restricted access to resources such as oxygen. Without oxygen to accept electrons from central metabolism, cellular redox homeostasis is disrupted. Using the pathogen Pseudomonas aeruginosa, a major cause of biofilm-based infections, the Dietrich lab studies the relationships between bacterial metabolism and biofilm development. P. aeruginosa is well-adapted to the biofilm lifestyle: it has a variety of efficient respiratory enzymes called terminal oxidases that are able to scavenge oxygen that is available at low concentrations, and it also produces redox-active molecules called phenazines that can substitute for oxygen to enable cellular redox balancing. In a recent study, the Dietrich lab uncovered roles for specific terminal oxidase complexes in optimal survival within a biofilm, pathogenicity in a nematode host, and utilization of phenazines. The image shows the unique colony biofilm morphology of a mutant lacking P. aeruginosa’s major terminal oxidases.
Reference: An orphan cbb3-type cytochrome oxidase subunit supports Pseudomonas aeruginosa biofilm growth and virulence
Columbia News: Researchers identify how bacterium survives in oxygen-poor environments
