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Kokgan Chan - One of the best experts on this subject based on the ideXlab platform.
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AidP, a novel N-Acyl Homoserine lactonase gene from Antarctic Planococcus sp.
Scientific Reports, 2017Co-Authors: Wah Seng See-too, Wai-fong Yin, Peter Convey, David A. Pearce, Yan-lue Lim, Kokgan ChanAbstract:Planococcus is a Gram-positive halotolerant bacterial genus in the phylum Firmicutes, commonly found in various habitats in Antarctica. Quorum quenching (QQ) is the disruption of bacterial cell-to-cell communication (known as quorum sensing), which has previously been described in mesophilic bacteria. This study demonstrated the QQ activity of a psychrotolerant strain, Planococcus versutus strain L10.15^T, isolated from a soil sample obtained near an elephant seal wallow in Antarctica. Whole genome analysis of this bacterial strain revealed the presence of an N -acyl Homoserine lactonase, an enzyme that hydrolyzes the ester bond of the Homoserine Lactone of N -acyl Homoserine Lactone (AHLs). Heterologous gene expression in E. coli confirmed its functions for hydrolysis of AHLs, and the gene was designated as aidP ( a uto i nducer d egrading gene from P lanococcus sp.). The low temperature activity of this enzyme suggested that it is a novel and uncharacterized class of AHL lactonase. This study is the first report on QQ activity of bacteria isolated from the polar regions.
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n acyl Homoserine Lactone mediated quorum sensing in aeromonas veronii biovar sobria strain 159 identification of luxri homologs
Frontiers in Cellular and Infection Microbiology, 2016Co-Authors: Xin Yue Chan, Wai-fong Yin, Kah Yan How, Kokgan ChanAbstract:16 Quorum sensing (QS) is a mechanism that plays important roles in gene expression in response to an 17 expanding bacterial population. In many Gram-negative bacteria, N-Acyl Homoserine Lactone is mainly 18 secreted as the diffusible signalling molecules. This QS system has been shown to control diverse array 19 of virulence and secondary metabolism. Recently, whole genome sequencing of Aeromonas veronii 20 biovar sobria strain 159 was performed. Genome comparison with closely-related Aeromonas species 21 showed that A. veronii strain 159 shares a high degree of genome synteny with A. hydrophila ATCC 22 7966. A detailed genome analysis and gene annotation led us to the findings that A. veronii strain 159 23 harbors QS system which relies on its signal generator, AveI and the transcriptional regulator, AveR. 24 This Aeromonas strain was found to secrete N-butanoylacyl Homoserine Lactone (C4-HSL). Its LuxIR 25 homologs are similar to proteins of LuxIR famililies among Aeromonas species. This study aims to 26 gain further insights into AveIR system and to compare with AhyIR from A. hydrophila ATCC 7966 27 and AsaIR from A. salmonicida. 28 29 30 31
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non antibiotic quorum sensing inhibitors acting against n acyl Homoserine Lactone synthase as druggable target
Scientific Reports, 2015Co-Authors: Chienyi Chang, Wai-fong Yin, Thiba Krishnan, Hao Wang, Ye Chen, Yee Meng Chong, Li Ying Tan, Teik Min Chong, Kokgan ChanAbstract:N-AcylHomoserine Lactone (AHL)-based quorum sensing (QS) is important for the regulation of proteobacterial virulence determinants. Thus, the inhibition of AHL synthases offers non-antibiotics-based therapeutic potentials against QS-mediated bacterial infections. In this work, functional AHL synthases of Pseudomonas aeruginosa LasI and RhlI were heterologously expressed in an AHL-negative Escherichia coli followed by assessments on their AHLs production using AHL biosensors and high resolution liquid chromatography–mass spectrometry (LCMS). These AHL-producing E. coli served as tools for screening AHL synthase inhibitors. Based on a campaign of screening synthetic molecules and natural products using our approach, three strongest inhibitors namely are salicylic acid, tannic acid and trans-cinnamaldehyde have been identified. LCMS analysis further confirmed tannic acid and trans-cinnemaldehyde efficiently inhibited AHL production by RhlI. We further demonstrated the application of trans-cinnemaldehyde inhibiting Rhl QS system regulated pyocyanin production in P. aeruginosa up to 42.06%. Molecular docking analysis suggested that trans-cinnemaldehyde binds to the LasI and EsaI with known structures mainly interacting with their substrate binding sites. Our data suggested a new class of QS-inhibiting agents from natural products targeting AHL synthase and provided a potential approach for facilitating the discovery of anti-QS signal synthesis as basis of novel anti-infective approach.
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quorum sensing activity in pandoraea pnomenusa rb38
Sensors, 2014Co-Authors: Yan-lue Lim, Wai-fong Yin, Linxin Kin, Kokgan ChanAbstract:Strain RB38 was recovered from a former dumping area in Malaysia. MALDI-TOF mass spectrometry and genomic analysis identified strain RB-38 as Pandoraea pnomenusa. Various biosensors confirmed its quorum sensing properties. High resolution triple quadrupole liquid chromatography-mass spectrometry analysis was subsequently used to characterize the N-Acyl Homoserine Lactone production profile of P. pnomenusa strain RB38, which validated that this isolate produced N-octanoyl Homoserine Lactone as a quorum sensing molecule. This is the first report of the production of N-octanoyl Homoserine Lactone by P. pnomenusa strain RB38.
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Characterisation of a Marine Bacterium Vibrio Brasiliensis T33 Producing N-Acyl Homoserine Lactone Quorum Sensing Molecules
MDPI AG, 2014Co-Authors: Wen-si Tan, Wai-fong Yin, Nina Yusrina Muhamad Yunos, Pui-wan Tan, Nur Izzati Mohamad, Tan-guan-sheng Adrian, Kokgan ChanAbstract:N-AcylHomoserine Lactones (AHL) plays roles as signal molecules in quorum sensing (QS) in most Gram-negative bacteria. QS regulates various physiological activities in relation with population density and concentration of signal molecules. With the aim of isolating marine water-borne bacteria that possess QS properties, we report here the preliminary screening of marine bacteria for AHL production using Chromobacterium violaceum CV026 as the AHL biosensor. Strain T33 was isolated based on preliminary AHL screening and further identified by using 16S rDNA sequence analysis as a member of the genus Vibrio closely related to Vibrio brasiliensis. The isolated Vibrio sp. strain T33 was confirmed to produce N-hexanoyl-l-Homoserine Lactone (C6-HSL) and N-(3-oxodecanoyl)-l-Homoserine Lactone (3-oxo-C10 HSL) through high resolution tandem mass spectrometry analysis. We demonstrated that this isolate formed biofilms which could be inhibited by catechin. To the best of our knowledge, this is the first report that documents the production of these AHLs by Vibrio brasiliensis strain T33
Wai-fong Yin - One of the best experts on this subject based on the ideXlab platform.
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AidP, a novel N-Acyl Homoserine lactonase gene from Antarctic Planococcus sp.
Scientific Reports, 2017Co-Authors: Wah Seng See-too, Wai-fong Yin, Peter Convey, David A. Pearce, Yan-lue Lim, Kokgan ChanAbstract:Planococcus is a Gram-positive halotolerant bacterial genus in the phylum Firmicutes, commonly found in various habitats in Antarctica. Quorum quenching (QQ) is the disruption of bacterial cell-to-cell communication (known as quorum sensing), which has previously been described in mesophilic bacteria. This study demonstrated the QQ activity of a psychrotolerant strain, Planococcus versutus strain L10.15^T, isolated from a soil sample obtained near an elephant seal wallow in Antarctica. Whole genome analysis of this bacterial strain revealed the presence of an N -acyl Homoserine lactonase, an enzyme that hydrolyzes the ester bond of the Homoserine Lactone of N -acyl Homoserine Lactone (AHLs). Heterologous gene expression in E. coli confirmed its functions for hydrolysis of AHLs, and the gene was designated as aidP ( a uto i nducer d egrading gene from P lanococcus sp.). The low temperature activity of this enzyme suggested that it is a novel and uncharacterized class of AHL lactonase. This study is the first report on QQ activity of bacteria isolated from the polar regions.
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n acyl Homoserine Lactone mediated quorum sensing in aeromonas veronii biovar sobria strain 159 identification of luxri homologs
Frontiers in Cellular and Infection Microbiology, 2016Co-Authors: Xin Yue Chan, Wai-fong Yin, Kah Yan How, Kokgan ChanAbstract:16 Quorum sensing (QS) is a mechanism that plays important roles in gene expression in response to an 17 expanding bacterial population. In many Gram-negative bacteria, N-Acyl Homoserine Lactone is mainly 18 secreted as the diffusible signalling molecules. This QS system has been shown to control diverse array 19 of virulence and secondary metabolism. Recently, whole genome sequencing of Aeromonas veronii 20 biovar sobria strain 159 was performed. Genome comparison with closely-related Aeromonas species 21 showed that A. veronii strain 159 shares a high degree of genome synteny with A. hydrophila ATCC 22 7966. A detailed genome analysis and gene annotation led us to the findings that A. veronii strain 159 23 harbors QS system which relies on its signal generator, AveI and the transcriptional regulator, AveR. 24 This Aeromonas strain was found to secrete N-butanoylacyl Homoserine Lactone (C4-HSL). Its LuxIR 25 homologs are similar to proteins of LuxIR famililies among Aeromonas species. This study aims to 26 gain further insights into AveIR system and to compare with AhyIR from A. hydrophila ATCC 7966 27 and AsaIR from A. salmonicida. 28 29 30 31
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non antibiotic quorum sensing inhibitors acting against n acyl Homoserine Lactone synthase as druggable target
Scientific Reports, 2015Co-Authors: Chienyi Chang, Wai-fong Yin, Thiba Krishnan, Hao Wang, Ye Chen, Yee Meng Chong, Li Ying Tan, Teik Min Chong, Kokgan ChanAbstract:N-AcylHomoserine Lactone (AHL)-based quorum sensing (QS) is important for the regulation of proteobacterial virulence determinants. Thus, the inhibition of AHL synthases offers non-antibiotics-based therapeutic potentials against QS-mediated bacterial infections. In this work, functional AHL synthases of Pseudomonas aeruginosa LasI and RhlI were heterologously expressed in an AHL-negative Escherichia coli followed by assessments on their AHLs production using AHL biosensors and high resolution liquid chromatography–mass spectrometry (LCMS). These AHL-producing E. coli served as tools for screening AHL synthase inhibitors. Based on a campaign of screening synthetic molecules and natural products using our approach, three strongest inhibitors namely are salicylic acid, tannic acid and trans-cinnamaldehyde have been identified. LCMS analysis further confirmed tannic acid and trans-cinnemaldehyde efficiently inhibited AHL production by RhlI. We further demonstrated the application of trans-cinnemaldehyde inhibiting Rhl QS system regulated pyocyanin production in P. aeruginosa up to 42.06%. Molecular docking analysis suggested that trans-cinnemaldehyde binds to the LasI and EsaI with known structures mainly interacting with their substrate binding sites. Our data suggested a new class of QS-inhibiting agents from natural products targeting AHL synthase and provided a potential approach for facilitating the discovery of anti-QS signal synthesis as basis of novel anti-infective approach.
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quorum sensing activity in pandoraea pnomenusa rb38
Sensors, 2014Co-Authors: Yan-lue Lim, Wai-fong Yin, Linxin Kin, Kokgan ChanAbstract:Strain RB38 was recovered from a former dumping area in Malaysia. MALDI-TOF mass spectrometry and genomic analysis identified strain RB-38 as Pandoraea pnomenusa. Various biosensors confirmed its quorum sensing properties. High resolution triple quadrupole liquid chromatography-mass spectrometry analysis was subsequently used to characterize the N-Acyl Homoserine Lactone production profile of P. pnomenusa strain RB38, which validated that this isolate produced N-octanoyl Homoserine Lactone as a quorum sensing molecule. This is the first report of the production of N-octanoyl Homoserine Lactone by P. pnomenusa strain RB38.
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Characterisation of a Marine Bacterium Vibrio Brasiliensis T33 Producing N-Acyl Homoserine Lactone Quorum Sensing Molecules
MDPI AG, 2014Co-Authors: Wen-si Tan, Wai-fong Yin, Nina Yusrina Muhamad Yunos, Pui-wan Tan, Nur Izzati Mohamad, Tan-guan-sheng Adrian, Kokgan ChanAbstract:N-AcylHomoserine Lactones (AHL) plays roles as signal molecules in quorum sensing (QS) in most Gram-negative bacteria. QS regulates various physiological activities in relation with population density and concentration of signal molecules. With the aim of isolating marine water-borne bacteria that possess QS properties, we report here the preliminary screening of marine bacteria for AHL production using Chromobacterium violaceum CV026 as the AHL biosensor. Strain T33 was isolated based on preliminary AHL screening and further identified by using 16S rDNA sequence analysis as a member of the genus Vibrio closely related to Vibrio brasiliensis. The isolated Vibrio sp. strain T33 was confirmed to produce N-hexanoyl-l-Homoserine Lactone (C6-HSL) and N-(3-oxodecanoyl)-l-Homoserine Lactone (3-oxo-C10 HSL) through high resolution tandem mass spectrometry analysis. We demonstrated that this isolate formed biofilms which could be inhibited by catechin. To the best of our knowledge, this is the first report that documents the production of these AHLs by Vibrio brasiliensis strain T33
Yinyue Deng - One of the best experts on this subject based on the ideXlab platform.
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disruption of quorum sensing and virulence in burkholderia cenocepacia by a structural analogue of the cis 2 dodecenoic acid signal
Applied and Environmental Microbiology, 2019Co-Authors: Shihao Song, Chunxi Yang, Yutong Huang, Kang Li, Shuo Zhao, Yongliang Zhang, Yinyue DengAbstract:Quorum sensing (QS) signals are widely used by bacterial pathogens to control biological functions and virulence in response to changes in cell population densities. Burkholderia cenocepacia employs a molecular mechanism in which the cis -2-dodecenoic acid (named B urkholderia d iffusible s ignal f actor, abbreviated as BDSF) QS system regulates N -acyl Homoserine Lactone (AHL) signal production and virulence by modulating intracellular levels of cyclic diguanosine monophosphate (c-di-GMP). Thus, inhibition of BDSF signaling may offer a non-antibiotic-based therapeutic strategy against BDSF-regulated bacterial infections. In this study, we report the synthesis of small molecule mimics of the BDSF signal and evaluate their ability to inhibit BDSF QS signaling in B. cenocepacia . A novel structural analogue of BDSF, 14-Me-C16:Δ 2 ( cis -14-methylpentadec-2-enoic acid), was observed to inhibit BDSF production and impair BDSF-regulated phenotypes in B. cenocepacia , including motility, biofilm formation and virulence, while it did not inhibit the growth rate of this pathogen. 14-Me-C16:Δ 2 also reduced AHL signal production. Genetic and biochemical analyses showed that 14-Me-C16:Δ 2 inhibited the production of the BDSF and AHL signals by decreasing the expression of their synthase-encoding genes. Notably, 14-Me-C16:Δ 2 attenuated BDSF-regulated phenotypes in various Burkholderia species. These findings suggest that 14-Me-C16:Δ 2 could potentially be developed as a new therapeutic agent against pathogenic Burkholderia species by interfering with their QS signaling. IMPORTANCE Burkholderia cenocepacia is an important opportunistic pathogen which can cause life-threatening infections in susceptible individuals, particularly in cystic fibrosis and immunocompromised patients. It usually employs two type quorum sensing (QS) systems, including the cis -2-dodecenoic acid (BDSF) system and N -acyl Homoserine Lactone (AHL) system, to regulate virulence. In this study, we have designed and identified an unsaturated fatty acid compound ( cis -14-methylpentadec-2-enoic acid, named as 14-Me-C16:Δ 2 ) that is capable of interfering with B. cenocepacia QS signaling and virulence. We demonstrate that 14-Me-C16:Δ 2 reduced BDSF and AHL signal production in B. cenocepacia . It also impaired QS-regulated phenotypes in various Burkholderia species. These results suggest that 14-Me-C16:Δ 2 could interfere with QS signaling in many Burkholderia species and might be developed as a new antibacterial agent.
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cis 2 dodecenoic acid quorum sensing system modulates n acyl Homoserine Lactone production through rpfr and cyclic di gmp turnover in burkholderia cenocepacia
BMC Microbiology, 2013Co-Authors: Yinyue Deng, Amy Lim, Jing Wang, Tielin Zhou, Shaohua Chen, Jasmine Lee, Yihu Dong, Lianhui ZhangAbstract:Background Burkholderia cenocepacia employs both N-Acyl Homoserine Lactone (AHL) and cis-2-dodecenoic acid (BDSF) quorum sensing (QS) systems in regulation of bacterial virulence. It was shown recently that disruption of BDSF synthase RpfFBc caused a reduction of AHL signal production in B. cenocepacia. However, how BDSF system influences AHL system is still not clear.
Lianhui Zhang - One of the best experts on this subject based on the ideXlab platform.
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cis 2 dodecenoic acid quorum sensing system modulates n acyl Homoserine Lactone production through rpfr and cyclic di gmp turnover in burkholderia cenocepacia
BMC Microbiology, 2013Co-Authors: Yinyue Deng, Amy Lim, Jing Wang, Tielin Zhou, Shaohua Chen, Jasmine Lee, Yihu Dong, Lianhui ZhangAbstract:Background Burkholderia cenocepacia employs both N-Acyl Homoserine Lactone (AHL) and cis-2-dodecenoic acid (BDSF) quorum sensing (QS) systems in regulation of bacterial virulence. It was shown recently that disruption of BDSF synthase RpfFBc caused a reduction of AHL signal production in B. cenocepacia. However, how BDSF system influences AHL system is still not clear.
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specificity and enzyme kinetics of the quorum quenching n acyl Homoserine Lactone lactonase ahl lactonase
Journal of Biological Chemistry, 2004Co-Authors: Lian-hui Wang, Yihu Dong, Lixing Weng, Lianhui ZhangAbstract:Abstract N-Acyl Homoserine Lactone (AHL) quorum-sensing signals are the vital elements of bacterial quorum-sensing systems, which regulate diverse biological functions, including virulence. The AHL-lactonase, a quorumquenching enzyme encoded by aiiA from Bacillus sp., inactivates AHLs by hydrolyzing the Lactone bond to produce corresponding N-Acyl Homoserines. To characterize the enzyme, the recombinant AHL-lactonase and its four variants were purified. Kinetic and substrate specificity analysis showed that AHL-lactonase had no or little residue activity to noN-Acyl Lactones and noncyclic esters, but displayed strong enzyme activity toward all tested AHLs, varying in length and nature of the substitution at the C3 position of the acyl chain. The data also indicate that the amide group and the ketone at the C1 position of the acyl chain of AHLs could be important structural features in enzyme-substrate interaction. Surprisingly, although carrying a 104HX- HXDH109 short sequence identical to the zinc-binding motif of several groups of metallohydrolytic enzymes, AHL-lactonase does not contain or require zinc or other metal ions for enzyme activity. Except for the amino acid residue His-104, which was shown previously to not be required for catalysis, kinetic study and conformational analysis using circular dichroism spectrometry showed that substitution of the other key residues in the motif (His-106, Asp-108, and His-109), as well as His-169 with serine, respectively, caused conformational changes and significant loss of enzyme activity. We conclude that AHL-lactonase is a highly specific enzyme and that the 106HXDH109∼H169 of AHL-lactonase represents a novel catalytic motif, which does not rely on zinc or other metal ions for activity.
Michael Givskov - One of the best experts on this subject based on the ideXlab platform.
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gfp based n acyl Homoserine Lactone sensor systems for detection of bacterial communication
Applied and Environmental Microbiology, 2001Co-Authors: Jens Bo Andersen, Arne Heydorn, Morten Hentzer, Leo Eberl, Otto Geisenberger, Bjarke Bak Christensen, Soren Molin, Michael GivskovAbstract:In recent years it has become apparent that bacteria coordinate their interaction and association with higher organisms by intercellular communication systems. In gram-negative bacteria, one type of communication system functions via small, diffusible N-Acyl Homoserine Lactone (AHL) signal molecules. The signals are synthesized from precursors by a synthase protein, “I,” and once they have reached a certain threshold concentration, they interact with a transcriptional activating “R” protein to induce expression of different target genes (for reviews see references 11, 13, and 43). Such regulatory systems operate as a quorum-sensing mechanism that allows bacteria to sense and express target genes in relation to their cell density. Several methods to detect the presence of AHL have been described. AHLs can be extracted from liquid cultures, purified to homogeneity by semipreparative high-performance liquid chromatography (HPLC), and identified by mass spectrometry and 1H nuclear magnetic resonance (NMR) spectroscopy (10). A number of bacterial sensor systems such as the pigment-developing Chromobacterium violaceum (30) and luxAB- and lacZ-based systems have been described (36, 50). Bioluminescent sensor systems have been conveniently used in Escherichia coli and have enabled the isolation and cloning of a number of I genes (31, 41, 42). A simple and convincing method for separation and tentative identification of AHL molecules in extracts of whole cultures has been developed; it consists of thin-layer chromatography (TLC) followed by detection of AHL molecules by means of agar overlay with sensor bacteria (36). Although these methods are very useful and highly sensitive, they do not allow for detection at the single-cell level or at the local environment. Furthermore, investigation of AHL expression based on population level analysis does not give information about local concentrations. A live bacterial AHL sensor that signals the presence of AHL molecules by expressing a reporter such as green fluorescent protein (GFP) can fulfil these requirements. GFP, obtained from the jellyfish Aequorea victoria, requires only trace amounts of oxygen to mature, i.e., no external compounds need to be added to organisms expressing GFP in order to detect green fluorescence (3). Previous work has demonstrated that GFP works well as a reporter for monitoring gene expression at the single-cell level in biofilms (4, 32, 39). Unfortunately, once formed, GFP is extremely stable (1, 47). Consequently, the GFP version used for monitoring fluctuations in AHL concentration should possess a species-independent instability. Previously, we have constructed a number of gfp genes (derived from gfpmut3 [6]) each of which encodes proteins with different half-lives ranging from 40 min to a few hours (1). Briefly, this was done by manipulating the gfp gene in such a way that the resultant protein carried C-terminal peptide tags which are recognized and to various extent rapidly degraded by housekeeping/intracellular tail-specific proteases (ClpP) (1, 17, 22, 23). In the present constructs the product of the luxR gene derived from Vibrio fischeri comprises the quorum sensor. In the presence of exogenous AHL molecules, LuxR positively affects the expression of the luxI promoter (PluxI), which then in turn controls expression of the gfp reporter. LuxR functions in a number of different bacterial strains (10, 19, 34, 41) and is responsive to a variety of AHL molecules (35, 50). Here we describe the construction and application of GFP-based AHL sensors.
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gfp based n acyl Homoserine Lactone sensor systems for detection of bacterial communication
Applied and Environmental Microbiology, 2001Co-Authors: Jens Bo Andersen, Arne Heydorn, Morten Hentzer, Leo Eberl, Otto Geisenberger, Bjarke Bak Christensen, Soren Molin, Michael GivskovAbstract:ABSTRACT In order to perform single-cell analysis and online studies ofN-Acyl Homoserine Lactone (AHL)-mediated communication among bacteria, components of the Vibrio fischeri quorum sensor encoded by luxR-PluxI have been fused to modified versions of gfpmut3∗ genes encoding unstable green fluorescent proteins. Bacterial strains harboring this green fluorescent sensor detected a broad spectrum of AHL molecules and were capable of sensing the presence of 5 nMN-3-oxohexanoyl-l-Homoserine Lactone in the surroundings. In combination with epifluorescent microscopy, the sensitivity of the sensor enabled AHL detection at the single-cell level and allowed for real-time measurements of fluctuations in AHL concentrations. This green fluorescent AHL sensor provides a state-of-the-art tool for studies of communication between the individuals present in mixed bacterial communities.
