SOS-inducible biofilms

Bacteria infecting eukaryotic hosts often encounter therapeutic antimicrobial and DNA damaging agents. They respond to these agents by forming biofilms. While mechanisms of the biofilm response are incompletely understood, it has been proposed that they involve the bacterial second messenger bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP) signaling and the SOS response. With Pseudomonas aeruginosa as a biofilm model, these mechanisms were investigated, and the findings are presented here. The results show that P. aeruginosa under DNA replication inhibition tends to form biofilms via Arr—a c-di-GMP phosphodiesterase. As DNA replication inhibition triggers SOS, the culprit of SOS is implicated in biofilm induction. Such a connection was examined. The data suggest that the stress-inducible biofilm formation is regulated by the interplay of the SOS regulators RecA and LexA.