Editing Quorum sensing (section)

==Quorum quenching==

Quorum quenching is the process of preventing quorum sensing by disrupting signalling.<ref name=":12">{{cite journal | vauthors = Alagarasan G, Aswathy KS | title = Shoot the Message, Not the Messenger-Combating Pathogenic Virulence in Plants by Inhibiting Quorum Sensing Mediated Signaling Molecules | journal = Frontiers in Plant Science | volume = 8 | pages = 556 | year = 2017 | pmid = 28446917 | pmc = 5388769 | doi = 10.3389/fpls.2017.00556 | doi-access = free }}</ref> This 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.<ref name=":3" /><ref name=":12" /><ref name=":22">{{cite journal | vauthors = Chan KG, Atkinson S, Mathee K, Sam CK, Chhabra SR, Cámara M, Koh CL, Williams P, Makar AB, McMartin KE, Palese M, Tephly TR, Glenn JK, Goldman J | display-authors = 6 | title = Task delegation to physician extenders--some comparisons | journal = American Journal of Public Health | volume = 66 | issue = 1 | pages = 64–66 | date = January 1976 | pmid = 21385437 <!-- |access-date=1 May 2022 --> | pmc = 3062576 | doi = 10.1186/1471-2180-11-51 | doi-access = free }}</ref><ref name="isolation3">{{cite journal | vauthors = Chan KG, Yin WF, Sam CK, Koh CL | title = A novel medium for the isolation of N-acylhomoserine lactone-degrading bacteria | journal = Journal of Industrial Microbiology & Biotechnology | volume = 36 | issue = 2 | pages = 247–251 | date = February 2009 | pmid = 18946694 | doi = 10.1007/s10295-008-0491-x | s2cid = 28637950 | doi-access = free }}</ref>

===Inhibition===

[[Closantel]] and [[triclosan]] are known inhibitors of quorum sensing enzymes.<ref name=":32">{{cite journal | vauthors = Basavaraju M, Sisnity VS, Palaparthy R, Addanki PK | title = Quorum quenching: Signal jamming in dental plaque biofilms | journal = Journal of Dental Sciences | volume = 11 | issue = 4 | pages = 349–352 | date = December 2016 | pmid = 30894996 | pmc = 6395279 | doi = 10.1016/j.jds.2016.02.002 }}</ref> Closantel induces aggregation of the [[histidine kinase]] sensor in two-component signalling. The latter disrupts the synthesis of a class of signalling molecules known as [[N-Acyl homoserine lactone|''N''-acyl homoserine lactones]] (AHLs) by blocking the [[Enoyl-acyl carrier protein reductase|enoyl-acyl carrier protein (ACP) reductase]].<ref name=":32" /><ref>{{cite journal | vauthors = Zhang LH, Dong YH | title = Quorum sensing and signal interference: diverse implications | journal = Molecular Microbiology | volume = 53 | issue = 6 | pages = 1563–1571 | date = September 2004 | pmid = 15341639 | doi = 10.1111/j.1365-2958.2004.04234.x | s2cid = 39018931 | doi-access = free }}</ref>

===Mimicry===

Two groups of well-known mimicking molecules include [[halogenated furanone]]s, which mimic AHL molecules, and synthetic Al peptides (AIPs), which mimic naturally occurring AIPs. These groups inhibit receptors from binding substrate or decrease the concentration of receptors in the cell.<ref name=":32" /> Furanones have also been found to act on AHL-dependant transcriptional activity, whereby the half life of the [[autoinducer]]-binding LuxR protein is significantly shortened.<ref>{{cite journal | vauthors = Manefield M, Rasmussen TB, Henzter M, Andersen JB, Steinberg P, Kjelleberg S, Givskov M | title = Halogenated furanones inhibit quorum sensing through accelerated LuxR turnover | journal = Microbiology | volume = 148 | issue = Pt 4 | pages = 1119–1127 | date = April 2002 | pmid = 11932456 | doi = 10.1099/00221287-148-4-1119 | doi-access = free }}</ref>

===Degradation===

Recently, a well-studied quorum quenching bacterial strain (KM1S) was isolated and its AHL degradation kinetics were studied using rapid resolution liquid [[chromatography]] (RRLC).<ref name="Rapid degradation3">{{cite journal | vauthors = Chan KG, Wong CS, Yin WF, Sam CK, Koh CL | title = Rapid degradation of N-3-oxo-acylhomoserine lactones by a Bacillus cereus isolate from Malaysian rainforest soil | journal = Antonie van Leeuwenhoek | volume = 98 | issue = 3 | pages = 299–305 | date = October 2010 | pmid = 20376561 | doi = 10.1007/s10482-010-9438-0 | s2cid = 12407347 }}</ref> RRLC efficiently separates components of a mixture to a high degree of sensitivity, based on their affinities for different liquid phases.<ref name=":52">{{cite journal | vauthors = Yoshida T, Majors RE | title = High-speed analyses using rapid resolution liquid chromatography on 1.8-microm porous particles | journal = Journal of Separation Science | volume = 29 | issue = 16 | pages = 2421–2432 | date = November 2006 | pmid = 17154122 | doi = 10.1002/jssc.200600267 }}</ref> It was found that the genome of this strain encoded an inactivation enzyme with distinct motifs targeting the degradation of AHLs.<ref name="Rapid degradation3" />

===Modifications===
As mentioned before, N-acyl-homoserine lactones (AHL) are the quorum sensing signaling molecules of the [[gram-negative bacteria]]. However, these molecules may have different functional groups on their acyl chain, and also a different length of acyl chain. Therefore, there exist many different AHL signaling molecules, for example, 3-oxododecanoyl-L-homoserine lactone (3OC12-HSL) or 3-hydroxydodecanoyl-L-homoserine lactone (3OHC12-HSL). The modification of those quorum sensing (QS) signaling molecules is another sort of quorum quenching. This can be carried out by an [[oxidoreductase]] activity.<ref name=":3" /> As an example, we will discuss the interaction between a host, ''[[Hydra vulgaris]]'', and the main colonizer of its epithelial cell surfaces, ''[[Curvibacter]]'' spp. Those bacteria produce 3-oxo-HSL quorum sensing molecules.<ref name=":3" /> However, the oxidoreductase activity of the polyp ''Hydra'' is able to modify the 3-oxo-HSL into their 3-hydroxy-HSL counterparts.<ref name=":3" /> We can characterize this as quorum quenching since there is an interference with quorum sensing molecules. In this case, the outcomes differ from simple QS inactivation: the host modification results in a phenotypic switch of ''Curvibacter'', which modifies its ability to colonize the epithelial cell surfaces of ''H. vulgaris''.<ref name=":3" />

===Applications===

Applications of quorum quenching that have been exploited by humans include the use of AHL-degrading bacteria in aquacultures to limit the spread of diseases in aquatic populations of fish, mollusks and crustaceans.<ref name=":42">{{cite journal | vauthors = Grandclément C, Tannières M, Moréra S, Dessaux Y, Faure D | title = Quorum quenching: role in nature and applied developments | journal = FEMS Microbiology Reviews | volume = 40 | issue = 1 | pages = 86–116 | date = January 2016 | pmid = 26432822 | doi = 10.1093/femsre/fuv038 | doi-access = free }}</ref> This technique has also been translated to agriculture, to restrict the spread of pathogenic bacteria that use quorum sensing in plants.<ref name=":42" /><ref>{{cite journal | vauthors = Galloway WR, Hodgkinson JT, Bowden S, Welch M, Spring DR | title = Applications of small molecule activators and inhibitors of quorum sensing in Gram-negative bacteria | journal = Trends in Microbiology | volume = 20 | issue = 9 | pages = 449–458 | date = September 2012 | pmid = 22771187 | doi = 10.1016/j.tim.2012.06.003 }}</ref> Anti-[[biofouling]] is another process that exploits quorum quenching bacteria to mediate the dissociation of unwanted biofilms aggregating on wet surfaces, such as medical devices, transportation infrastructure and water systems.<ref name=":42" /><ref name=":62">{{Cite journal| vauthors = Liu CX, Zhang DR, He Y, Zhao XS, Bai R |title=Modification of membrane surface for anti-biofouling performance: Effect of anti-adhesion and anti-bacteria approaches|journal=[[Journal of Membrane Science]]|volume=346|issue=1|pages=121–130|doi=10.1016/j.memsci.2009.09.028|year=2010}}</ref> Quorum quenching is recently studied for the control of fouling and emerging contaminants in electro membrane bioreactors (eMBRs) for the advanced treatment of wastewater.<ref name=":43">{{cite journal | vauthors = Borea L, Naddeo V, Belgiorno V, Choo KH | title = Control of quorum sensing signals and emerging contaminants in electrochemical membrane bioreactors | journal = Bioresource Technology | volume = 269 | pages = 89–95 | date = December 2018 | pmid = 30153550 | doi = 10.1016/j.biortech.2018.08.041 | bibcode = 2018BiTec.269...89B | s2cid = 52134789 }}</ref>  Extracts of several traditional medicinal herbs display quorum quenching activity, and have potential antibacterial applications.<ref>{{cite journal | vauthors = Moradi F, Hadi N | title = Quorum-quenching activity of some Iranian medicinal plants | journal = New Microbes and New Infections | volume = 42 | pages = 100882 | date = July 2021 | pmid = 34094582 | pmc = 8165558 | doi = 10.1016/j.nmni.2021.100882 }}</ref><ref>{{cite journal | vauthors = Moradi F, Hadi N, Bazargani A | title = Evaluation of quorum-sensing inhibitory effects of extracts of three traditional medicine plants with known antibacterial properties | journal = New Microbes and New Infections | volume = 38 | pages = 100769 | date = November 2020 | pmid = 33194208 | pmc = 7644747 | doi = 10.1016/j.nmni.2020.100769 }}</ref>