A Flavor Lactone Mimicking AHL Quorum-Sensing Signals Exploits the Broad Affinity of the QsdR Regulator to Stimulate Transcription of the Rhodococcal qsd Operon Involved in Quorum-Quenching and Biocontrol Activities

ABSTRACTSsoPox, a bifunctional enzyme with organophosphate hydrolase andN-acyl homoserine lactonase activities from the hyperthermophilic archaeonSulfolobus solfataricus, was overexpressed and purified from recombinantPseudomonas putidaKT2440 with a yield of 9.4 mg of protein per liter of culture. The enzyme has a preference forN-acyl homoserine lactones (AHLs) with acyl chain lengths of at least 8 carbon atoms, mainly due to lowerKmvalues for these substrates. The highest specificity constant obtained was forN-3-oxo-decanoyl homoserine lactone (kcat/Km= 5.5 × 103M−1·s−1), but SsoPox can also degradeN-butyryl homoserine lactone (C4-HSL) andN-oxo-dodecanoyl homoserine lactone (oxo-C12-HSL), which are important for quorum sensing in ourPseudomonas aeruginosamodel system. WhenP. aeruginosaPAO1 cultures were grown in the presence of SsoPox-immobilized membranes, the production of C4-HSL- and oxo-C12-HSL-regulated virulence factors, elastase, protease, and pyocyanin were significantly reduced. This is the first demonstration that immobilized quorum-quenching enzymes can be used to attenuate the production of virulence factors controlled by quorum-sensing signals.

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Cyclic Dipeptides Produced by Marine Sponge-Associated Bacteria as Quorum Sensing Signals

Natural Product Communications ◽

10.1177/1934578x1400900225 ◽

2014 ◽

Vol 9 (2) ◽

pp. 1934578X1400900

Author(s):

Gennaro Roberto Abbamondi ◽

Salvatore De Rosa ◽

Carmine Iodice ◽

Giuseppina Tommonaro

Keyword(s):

Quorum Sensing ◽

Quorum Quenching ◽

Marine Sponges ◽

Bacterial Strains ◽

Signal Molecule ◽

Associated Bacteria ◽

Cyclic Dipeptides ◽

Sponge Associated Bacteria ◽

Dysidea Avara ◽

Quorum Sensing Signals

Four bacterial strains belonging to the genera Vibrio, Pseudoalteromonas and Photobacterium were isolated from the marine sponges Dysidea avara and Geodia cynodium. A Bacillus strain was isolated from Ircinia variabilis. A screening of molecules involved in quorum sensing (QS) was carried out by TLC-overlay and a new “plate T-streak” test. To analyze quorum quenching (QQ), a plate T-streak was performed with Chromobacterium violaceum. Strains of Vibrio isolated from both marine sponges and a strain of Photobacterium isolated from G. cynodium, activated QS bioreporters. A strain of Pseudoalteromonas isolated from D. avara showed QQ activity. Finally, it is reported that cyclic dipeptides isolated from strains of Vibrio sp. and Bacillus sp. (isolated from D. avara and I. variabilis, respectively) were involved in the QS mechanism. The simultaneous presence of bacteria that showed contrasting responses in bioassays for QS signal molecule synthesis in marine sponges could add an interesting dimension to the signalling interactions which may be happening in sponges.

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Detection and Analysis of Quorum‐Quenching Enzymes Against Acyl Homoserine Lactone Quorum‐Sensing Signals

Current Protocols in Microbiology ◽

10.1002/9780471729259.mc01c03s05 ◽

2007 ◽

Vol 5 (1) ◽

Cited By ~ 11

Author(s):

Hai‐Bao Zhang ◽

Lian‐Hui Wang ◽

Lian‐Hui Zhang

Keyword(s):

Quorum Sensing ◽

Quorum Quenching ◽

Homoserine Lactone ◽

Acyl Homoserine Lactone ◽

Quorum Sensing Signals

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Where Does Current Quorum Sensing Research Stand

10.47496/sl.blog.16 ◽

2020 ◽

Author(s):

Spring Library

Keyword(s):

Enzyme Activity ◽

Quorum Sensing ◽

Quorum Quenching ◽

Signalling Molecules ◽

Quorum Sensing Signals

Quorum quenching is achieved by inactivating signalling enzymes, by introducing molecules that mimic signalling molecules and block their receptors, by degrading signalling molecules themselves, or by a modification of the quorum sensing signals due to an enzyme activity.

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