Quinolone Signals Related to Pseudomonas Quinolone Signal-Quorum Sensing Inhibits the Predatory Activity of Bdellovibrio bacteriovorus

Bdellovibrio bacteriovorus is one of the predatory bacteria; therefore, it can act as a novel “living antibiotic,” unlike the current antibiotics. Here the predation of Escherichia coli by B. bacteriovorus was inhibited in the presence of Pseudomonas aeruginosa. This study investigated whether P. aeruginosa-induced predation inhibition is associated with bacterial quorum sensing (QS). Each las, rhl, or pqs QS mutant in P. aeruginosa was used to check the predatory activity of E. coli cells using B. bacteriovorus. As a result, the predatory activity of B. bacteriovorus increased in a mutant pqs QS system, whereas wild-type PA14 inhibited the predatory activity. Moreover, the addition of 4-hydroxy-2-heptylquinoline (HHQ) or the analog triggered the low predatory activity of B. bacteriovorus and killed B. bacteriovorus cells. Therefore, a defensive action of P. aeruginosa against B. bacteriovorus is activated by the pqs QS system, which produces some quinolone compounds such as HHQ.

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An investigation of the interactions between an E. coli bacterial quorum sensing biosensor and chitosan-based nanocapsules

Colloids and Surfaces B Biointerfaces ◽

10.1016/j.colsurfb.2016.10.031 ◽

2017 ◽

Vol 149 ◽

pp. 358-368 ◽

Cited By ~ 19

Author(s):

Xiaofei Qin ◽

Christoph Engwer ◽

Saaketh Desai ◽

Celina Vila-Sanjurjo ◽

Francisco M. Goycoolea

Keyword(s):

Quorum Sensing ◽

E Coli ◽

Bacterial Quorum Sensing ◽

Bacterial Quorum

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Synthesis and biological evaluation of novel acyclic and cyclic glyoxamide based derivatives as bacterial quorum sensing and biofilm inhibitors

Organic & Biomolecular Chemistry ◽

10.1039/c7ob01011g ◽

2017 ◽

Vol 15 (27) ◽

pp. 5743-5755 ◽

Cited By ~ 8

Author(s):

Shashidhar Nizalapur ◽

Onder Kimyon ◽

Eugene Yee ◽

Mohan M. Bhadbhade ◽

Mike Manefield ◽

...

Keyword(s):

Quorum Sensing ◽

Biofilm Formation ◽

Biological Evaluation ◽

Gram Negative Bacteria ◽

Gram Negative ◽

E Coli ◽

Sensing Mechanism ◽

Bacterial Quorum Sensing ◽

Bacterial Quorum ◽

Synthesis And Biological Evaluation

Novel acyclic and cyclic glyoxamides that inhibited quorum sensing mechanism and biofilm formation in Gram-negative bacteria such as P. aeruginosa and E. coli.

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Cross-kingdom signalling: exploitation of bacterial quorum sensing molecules by the green seaweed Ulva

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2007.2047 ◽

2007 ◽

Vol 362 (1483) ◽

pp. 1223-1233 ◽

Cited By ~ 95

Author(s):

Ian Joint ◽

Karen Tait ◽

Glen Wheeler

Keyword(s):

Quorum Sensing ◽

Calcium Influx ◽

Calcium Signalling ◽

Signal Molecules ◽

Wild Type ◽

Bacterial Quorum Sensing ◽

Green Seaweed ◽

Bacterial Quorum ◽

Lines Of Evidence

The green seaweed Ulva has been shown to detect signal molecules produced by bacteria. Biofilms that release N -acylhomoserine lactones (AHLs) attract zoospores—the motile reproductive stages of Ulva . The evidence for AHL involvement is based on several independent lines of evidence, including the observation that zoospores are attracted to wild-type bacteria that produce AHLs but are not attracted to mutants that do not produce signal molecules. Synthetic AHL also attracts zoospores and the attraction is lost in the presence of autoinducer inactivation (AiiA) protein. The mechanism of attraction is not chemotactic but involves chemokinesis. When zoospores detect AHLs, the swimming rate is reduced and this results in accumulation of cells at the source of the AHL. It has been demonstrated that the detection of AHLs results in calcium influx into the zoospore. This is the first example of a calcium signalling event in a eukaryote in response to bacterial quorum sensing molecules. The role of AHLs in the ecology of Ulva is discussed. It is probable that AHLs act as cues for the settlement of zoospores, rather than being directly involved as a signalling mechanism.

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Screening of Bacterial Quorum Sensing Inhibitors in a Vibrio fischeri LuxR-Based Synthetic Fluorescent E. coli Biosensor

Pharmaceuticals ◽

10.3390/ph13090263 ◽

2020 ◽

Vol 13 (9) ◽

pp. 263

Author(s):

Xiaofei Qin ◽

Celina Vila-Sanjurjo ◽

Ratna Singh ◽

Bodo Philipp ◽

Francisco M. Goycoolea

Keyword(s):

Quorum Sensing ◽

Bacterial Growth ◽

Vibrio Fischeri ◽

Caffeic Acid Phenethyl Ester ◽

Docking Studies ◽

Inhibition Activity ◽

E Coli ◽

Bacterial Quorum Sensing ◽

Pure Compounds ◽

Bacterial Quorum

A library of 23 pure compounds of varying structural and chemical characteristics was screened for their quorum sensing (QS) inhibition activity using a synthetic fluorescent Escherichia coli biosensor that incorporates a modified version of lux regulon of Vibrio fischeri. Four such compounds exhibited QS inhibition activity without compromising bacterial growth, namely, phenazine carboxylic acid (PCA), 2-heptyl-3-hydroxy-4-quinolone (PQS), 1H-2-methyl-4-quinolone (MOQ) and genipin. When applied at 50 µM, these compounds reduced the QS response of the biosensor to 33.7% ± 2.6%, 43.1% ± 2.7%, 62.2% ± 6.3% and 43.3% ± 1.2%, respectively. A series of compounds only showed activity when tested at higher concentrations. This was the case of caffeine, which, when applied at 1 mM, reduced the QS to 47% ± 4.2%. In turn, capsaicin, caffeic acid phenethyl ester (CAPE), furanone and polygodial exhibited antibacterial activity when applied at 1mM, and reduced the bacterial growth by 12.8% ± 10.1%, 24.4% ± 7.0%, 91.4% ± 7.4% and 97.5% ± 3.8%, respectively. Similarly, we confirmed that trans-cinnamaldehyde and vanillin, when tested at 1 mM, reduced the QS response to 68.3% ± 4.9% and 27.1% ± 7.4%, respectively, though at the expense of concomitantly reducing cell growth by 18.6% ± 2.5% and 16% ± 2.2%, respectively. Two QS natural compounds of Pseudomonas aeruginosa, namely PQS and PCA, and the related, synthetic compounds MOQ, 1H-3-hydroxyl-4-quinolone (HOQ) and 1H-2-methyl-3-hydroxyl-4-quinolone (MHOQ) were used in molecular docking studies with the binding domain of the QS receptor TraR as a target. We offer here a general interpretation of structure-function relationships in this class of compounds that underpins their potential application as alternatives to antibiotics in controlling bacterial virulence.

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