title: Biotic inactivation of the Pseudomonas aeruginosa quinolone signal molecule.
abstract: In Pseudomonas aeruginosa, quorum sensing (QS) regulates the production of secondary metabolites, many of which are antimicrobials that impact on polymicrobial community composition. Consequently, quenching QS modulates the environmental impact of P. aeruginosa. To identify bacteria capable of inactivating the QS signal molecule 2-heptyl-3-hydroxy-4(1H)-quinolone (PQS), a minimal medium containing PQS as the sole carbon source was used to enrich a Malaysian rainforest soil sample. This yielded an Achromobacter xylosoxidans strain (Q19) that inactivated PQS, yielding a new fluorescent compound (I-PQS) confirmed as PQS-derived using deuterated PQS. The I-PQS structure was elucidated using mass spectrometry and nuclear magnetic resonance spectroscopy as 2-heptyl-2-hydroxy-1,2-dihydroquinoline-3,4-dione (HHQD). Achromobacter xylosoxidans Q19 oxidized PQS congeners with alkyl chains ranging from C1 to C5 and also N-methyl PQS, yielding the corresponding 2-hydroxy-1,2-dihydroquinoline-3,4-diones, but was unable to inactivate the PQS precursor HHQ. This indicates that the hydroxyl group at position 3 in PQS is essential and that A. xylosoxidans inactivates PQS via a pathway involving the incorporation of oxygen at C2 of the heterocyclic ring. The conversion of PQS to HHQD also occurred on incubation with 12/17 A. xylosoxidans strains recovered from cystic fibrosis patients, with P. aeruginosa and with Arthrobacter, suggesting that formation of hydroxylated PQS may be a common mechanism of inactivation.
authors: Centre for Biomolecular Sciences, School of Life Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD, UK.|Division of Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, 50603, Malaysia.
authors: Eliza Ye-Chen
authors: EY
authors: Soh
authors: Centre for Biomolecular Sciences, School of Life Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD, UK.
authors: Siri R
authors: SR
authors: Chhabra
authors: Centre for Biomolecular Sciences, School of Life Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD, UK.
authors: Nigel
authors: N
authors: Halliday
authors: Centre for Biomolecular Sciences, School of Life Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD, UK.
authors: Stephan
authors: S
authors: Heeb
authors: Institute of Molecular Microbiology and Biotechnology, University of Muenster, D-48149, Muenster, Germany.
authors: Christine
authors: C
authors: Müller
authors: Institute of Molecular Microbiology and Biotechnology, University of Muenster, D-48149, Muenster, Germany.
authors: Franziska S
authors: FS
authors: Birmes
authors: Institute of Molecular Microbiology and Biotechnology, University of Muenster, D-48149, Muenster, Germany.
authors: Susanne
authors: S
authors: Fetzner
authors: Centre for Biomolecular Sciences, School of Life Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD, UK.
authors: Miguel
authors: M
authors: Cámara
authors: Division of Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, 50603, Malaysia.
authors: Kok-Gan
authors: KG
authors: Chan
authors: Centre for Biomolecular Sciences, School of Life Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD, UK.
authors: Paul
authors: P
authors: Williams
mesh_terms: D042441:Achromobacter denitrificans / Q000378:metabolism*; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D011550:Pseudomonas aeruginosa / Q000378:metabolism*; D015363:Quinolones / Q000378:metabolism*; D053038:Quorum Sensing / Q000502:physiology*; D065947:Rainforest; D064210:Secondary Metabolism / Q000502:physiology*; D015398:Signal Transduction; D012987:Soil / Q000737:chemistry; D012988:Soil Microbiology
chemical_list: C407944:2-heptyl-3-hydroxy-4-quinolone; D015363:Quinolones; D012987:Soil