title: Enzyme-Mediated Quenching of thePseudomonasQuinolone Signal (PQS) Promotes Biofilm Formation ofPseudomonas aeruginosaby Increasing Iron Availability.
abstract: The 2-alkyl-3-hydroxy-4(1H)-quinolone 2,4-dioxygenase HodC was previously described to cleave thePseudomonasquinolone signal, PQS, which is exclusively used in the complex quorum sensing (QS) system ofPseudomonas aeruginosa, an opportunistic pathogen employing QS to regulate virulence and biofilm development. Degradation of PQS by exogenous addition of HodC to planktonic cells ofP. aeruginosaattenuated production of virulence factors, and reduced virulencein planta. However, proteolytic cleavage reduced the efficacy of HodC. Here, we identified the secreted protease LasB ofP. aeruginosato be responsible for HodC degradation. In static biofilms of theP. aeruginosaPA14lasB::Tn mutant, the catalytic activity of HodC led to an increase in viable biomass in newly formed but also in established biofilms, and reduced the expression of genes involved in iron metabolism and siderophore production, such aspvdS, pvdL, pvdA, andpvdQ. This is likely due to an increase in the levels of bioavailable iron by degradation of PQS, which is able to sequester iron from the surrounding environment. Thus, HodC, despite its ability to quench the production of virulence factors, is contraindicated for combatingP. aeruginosabiofilms.
authors.affiliation: Karlsruhe Institute of Technology, Institute of Functional Interfaces Karlsruhe, Germany.
authors.forename: Beatrix
authors.initials: B
authors.lastname: Tettmann
authors.affiliation: Institute for Molecular Microbiology and Biotechnology, University of Münster Münster, Germany.
authors.forename: Christine
authors.initials: C
authors.lastname: Niewerth
authors.affiliation: Karlsruhe Institute of Technology, Institute of Functional Interfaces Karlsruhe, Germany.
authors.forename: Frank
authors.initials: F
authors.lastname: Kirschhöfer
authors.affiliation: Karlsruhe Institute of Technology, Institute of Functional Interfaces Karlsruhe, Germany.
authors.forename: Anke
authors.initials: A
authors.lastname: Neidig
authors.affiliation: Karlsruhe Institute of Technology, Institute of Functional Interfaces Karlsruhe, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Dötsch
authors.affiliation: Karlsruhe Institute of Technology, Institute of Functional Interfaces Karlsruhe, Germany.
authors.forename: Gerald
authors.initials: G
authors.lastname: Brenner-Weiss
authors.affiliation: Institute for Molecular Microbiology and Biotechnology, University of Münster Münster, Germany.
authors.forename: Susanne
authors.initials: S
authors.lastname: Fetzner
authors.affiliation: Karlsruhe Institute of Technology, Institute of Functional Interfaces Karlsruhe, Germany.
authors.forename: Joerg
authors.initials: J
authors.lastname: Overhage
keywords: PQS dioxygenase; Pseudomonas aeruginosa; Pseudomonas quinolone signal; biofilm; quorum quenching; quorum sensing