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Billot R, Plener L, Jacquet P, Elias M, Chabrière E, Daudé D. Engineering acyl-homoserine lactone-interfering enzymes toward bacterial control. J Biol Chem 2020; 295:12993-13007. [PMID: 32690609 DOI: 10.1074/jbc.rev120.013531] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 07/17/2020] [Indexed: 12/20/2022] Open
Abstract
Enzymes able to degrade or modify acyl-homoserine lactones (AHLs) have drawn considerable interest for their ability to interfere with the bacterial communication process referred to as quorum sensing. Many proteobacteria use AHL to coordinate virulence and biofilm formation in a cell density-dependent manner; thus, AHL-interfering enzymes constitute new promising antimicrobial candidates. Among these, lactonases and acylases have been particularly studied. These enzymes have been isolated from various bacterial, archaeal, or eukaryotic organisms and have been evaluated for their ability to control several pathogens. Engineering studies on these enzymes were carried out and successfully modulated their capacity to interact with specific AHL, increase their catalytic activity and stability, or enhance their biotechnological potential. In this review, special attention is paid to the screening, engineering, and applications of AHL-modifying enzymes. Prospects and future opportunities are also discussed with a view to developing potent candidates for bacterial control.
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Affiliation(s)
- Raphaël Billot
- Gene&GreenTK, Marseille, France; IRD, APHM, MEPHI, IHU-Méditerranée Infection, Aix-Marseille Université, Marseille, France
| | | | | | - Mikael Elias
- Molecular Biology and Biophysics and Biotechnology Institute, Department of Biochemistry, University of Minnesota, St. Paul, Minnesota, USA
| | - Eric Chabrière
- IRD, APHM, MEPHI, IHU-Méditerranée Infection, Aix-Marseille Université, Marseille, France.
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52
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Shrestha A, Grimm M, Ojiro I, Krumwiede J, Schikora A. Impact of Quorum Sensing Molecules on Plant Growth and Immune System. Front Microbiol 2020; 11:1545. [PMID: 32765447 PMCID: PMC7378388 DOI: 10.3389/fmicb.2020.01545] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 06/15/2020] [Indexed: 02/05/2023] Open
Abstract
Bacterial quorum-sensing (QS) molecules are one of the primary means allowing communication between bacterial cells or populations. Plants also evolved to perceive and respond to those molecules. N-acyl homoserine lactones (AHL) are QS molecules, of which impact has been extensively studied in different plants. Most studies, however, assessed the interactions in a bilateral manner, a nature of interactions, which occurs rarely, if at all, in nature. Here, we investigated how Arabidopsis thaliana responds to the presence of different single AHL molecules and their combinations. We assumed that this reflects the situation in the rhizosphere more accurately than the presence of a single AHL molecule. In order to assess those effects, we monitored the plant growth and defense responses as well as resistance to the plant pathogen Pseudomonas syringae pathovar tomato (Pst). Our results indicate that the complex interactions between multiple AHL and plants may have surprisingly similar outcomes. Individually, some of the AHL molecules positively influenced plant growth, while others induced the already known AHL-priming for induced resistance. Their combinations had a relatively low impact on the growth but seemed to induce resistance mechanisms. Very striking was the fact that all triple, the quadruple as well as the double combination(s) with long-chained AHL molecules increased the resistance to Pst. These findings indicate that induced resistance against plant pathogens could be one of the major outcomes of an AHL perception. Taken together, we present here the first study on how plants respond to the complexity of bacterial quorum sensing.
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Affiliation(s)
- Abhishek Shrestha
- Institute for Epidemiology and Pathogen Diagnostics, Federal Research Centre for Cultivated Plants, Julius Kühn-Institut, Braunschweig, Germany
| | - Maja Grimm
- Institute for Epidemiology and Pathogen Diagnostics, Federal Research Centre for Cultivated Plants, Julius Kühn-Institut, Braunschweig, Germany
| | - Ichie Ojiro
- Faculty of Agriculture, Shizuoka University, Shizuoka, Japan
| | - Johannes Krumwiede
- Institute for Epidemiology and Pathogen Diagnostics, Federal Research Centre for Cultivated Plants, Julius Kühn-Institut, Braunschweig, Germany
| | - Adam Schikora
- Institute for Epidemiology and Pathogen Diagnostics, Federal Research Centre for Cultivated Plants, Julius Kühn-Institut, Braunschweig, Germany
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Ortiz BJ, Boursier ME, Barrett KL, Manson DE, Amador-Noguez D, Abbott NL, Blackwell HE, Lynn DM. Liquid Crystal Emulsions That Intercept and Report on Bacterial Quorum Sensing. ACS APPLIED MATERIALS & INTERFACES 2020; 12:29056-29065. [PMID: 32484648 PMCID: PMC7343617 DOI: 10.1021/acsami.0c05792] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We report aqueous emulsions of thermotropic liquid crystals (LCs) that can intercept and report on the presence of N-acyl-l-homoserine lactones (AHLs), a class of amphiphiles used by pathogenic bacteria to regulate quorum sensing (QS), monitor population densities, and initiate group activities, including biofilm formation and virulence factor production. The concentration of AHL required to promote "bipolar" to "radial" transitions in micrometer-scale droplets of the nematic LC 4'-pentyl-cyanobiphenyl (5CB) decreases with increasing carbon number in the acyl tail, reaching a threshold concentration of 7.1 μM for 3-oxo-C12-AHL, a native QS signal in the pathogen Pseudomonas aeruginosa. The LC droplets in these emulsions also respond to biologically relevant concentrations of the biosurfactant rhamnolipid, a virulence factor produced by communities of P. aeruginosa under the control of QS. Systematic studies using bacterial mutants support the conclusion that these emulsions respond selectively to the production of rhamnolipid and AHLs and not to other products produced by bacteria at lower (subquorate) population densities. Finally, these emulsions remain configurationally stable in growth media, enabling them to be deployed either in bacterial supernatants or in situ in bacterial cultures to eavesdrop on QS and report on changes in bacterial group behavior that can be detected in real time using polarized light. Our results provide new tools to detect and report on bacterial QS and virulence and a materials platform for the rapid and in situ monitoring of bacterial communication and resulting group behaviors in bacterial communities.
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Affiliation(s)
- Benjamín J Ortiz
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, Wisconsin 53706, United States
| | - Michelle E Boursier
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Kelsey L Barrett
- Department of Bacteriology, University of Wisconsin-Madison, 1550 Linden Drive, Madison, Wisconsin 53706, United States
| | - Daniel E Manson
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Daniel Amador-Noguez
- Department of Bacteriology, University of Wisconsin-Madison, 1550 Linden Drive, Madison, Wisconsin 53706, United States
| | - Nicholas L Abbott
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, Wisconsin 53706, United States
| | - Helen E Blackwell
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - David M Lynn
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, Wisconsin 53706, United States
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
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54
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Panthee S, Kito N, Hayashi T, Shimizu T, Ishikawa J, Hamamoto H, Osada H, Takahashi S. β-carboline chemical signals induce reveromycin production through a LuxR family regulator in Streptomyces sp. SN-593. Sci Rep 2020; 10:10230. [PMID: 32576869 PMCID: PMC7311520 DOI: 10.1038/s41598-020-66974-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 05/27/2020] [Indexed: 12/21/2022] Open
Abstract
Actinomycetes bacteria produce diverse bioactive molecules that are useful as drug seeds. To improve their yield, researchers often optimize the fermentation medium. However, exactly how the extracellular chemicals present in the medium activate secondary metabolite gene clusters remains unresolved. BR-1, a β-carboline compound, was recently identified as a chemical signal that enhanced reveromycin A production in Streptomyces sp. SN-593. Here we show that BR-1 specifically bound to the transcriptional regulator protein RevU in the reveromycin A biosynthetic gene cluster, and enhanced RevU binding to its promoter. RevU belongs to the LuxR family regulator that is widely found in bacteria. Interestingly, BR-1 and its derivatives also enhanced the production of secondary metabolites in other Streptomyces species. Although LuxR-N-acyl homoserine lactone systems have been characterized in Gram-negative bacteria, we revealed LuxR-β-carboline system in Streptomyces sp. SN-593 for the production of secondary metabolites. This study might aid in understanding hidden chemical communication by β-carbolines.
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Affiliation(s)
- Suresh Panthee
- RIKEN Center for Sustainable Resource Science, Natural Product Biosynthesis Research Unit, Wako, Hirosawa 2-1, 351-0198, Saitama, Japan.,Teikyo University Institute of Medical Mycology, Otsuka 359, Hachioji, Tokyo, Japan
| | - Naoko Kito
- RIKEN Center for Sustainable Resource Science, Natural Product Biosynthesis Research Unit, Wako, Hirosawa 2-1, 351-0198, Saitama, Japan
| | - Teruo Hayashi
- RIKEN Center for Sustainable Resource Science, Chemical Biology Research Group, Wako, Hirosawa 2-1, 351-0198, Saitama, Japan
| | - Takeshi Shimizu
- RIKEN Center for Sustainable Resource Science, Chemical Biology Research Group, Wako, Hirosawa 2-1, 351-0198, Saitama, Japan
| | - Jun Ishikawa
- Department of Bioactive Molecules, National Institute of Infectious Diseases, Toyama 1-23-1, Shinjuku, Tokyo, 162-8640, Japan
| | - Hiroshi Hamamoto
- Teikyo University Institute of Medical Mycology, Otsuka 359, Hachioji, Tokyo, Japan
| | - Hiroyuki Osada
- RIKEN Center for Sustainable Resource Science, Chemical Biology Research Group, Wako, Hirosawa 2-1, 351-0198, Saitama, Japan.
| | - Shunji Takahashi
- RIKEN Center for Sustainable Resource Science, Natural Product Biosynthesis Research Unit, Wako, Hirosawa 2-1, 351-0198, Saitama, Japan.
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55
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Huang S, Zhang H, Albert Ng TC, Xu B, Shi X, Ng HY. Analysis of N-Acy-L-homoserine lactones (AHLs) in wastewater treatment systems using SPE-LLE with LC-MS/MS. WATER RESEARCH 2020; 177:115756. [PMID: 32294590 DOI: 10.1016/j.watres.2020.115756] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 03/03/2020] [Accepted: 03/26/2020] [Indexed: 06/11/2023]
Abstract
The occurrence and distribution of N-acyl homoserine lactones (AHLs) in membrane bioreactors (MBRs) treating wastewater has garnered much attention as they have been shown to play critical role in biofouling. There is a need to develop a single method capable of analysing AHLs in various wastewater with comparable and reliable performance. A novel and robust method was proposed for trace analysis of 11 AHLs in wastewater treatment systems treating domestic and industrial wastewater. This method utilised solid phase extraction (SPE) to extract AHLs from wastewater followed by liquid-liquid extraction (LLE) to extract AHLs from the SPE eluant, and used N-heptanoyl-dl-homoserine lactone (C7-HSL) as an internal standard. There was no need to prepare matrix-matched calibration curve for accurate quantification of AHLs in the liquid chromatography tandem mass chromatography (LC-MS/MS) analysis. The developed method was validated with six different types of domestic and industrial wastewater with regard to AHLs recoveries and matrix effects. For treated domestic and industrial wastewater, the relative recoveries ranged from 75% to 130% and the matrix effects ranged from 89% to 122%. This method exhibited remarkable improvement compared with single SPE. The results also indicated that inclusion of LLE after SPE could effectively alleviate matrix effects, which may be because of the removal of relatively hydrophilic interferences by using dichloromethane to extract AHLs from the SPE eluant composing of methanol and water. The limits of detection of the AHLs were all below 5 ng/L for the tested wastewater samples. The developed method of SPE-LLE with LC-MS/MS was applied to analyse AHLs in four lab-scale and one pilot-scale wastewater treatment systems. Wide spectrum of AHLs with alkanoyl chains ranging from C4 to C14 were detected with concentrations ranging from 2.7 to 299.2 ng/L. This method is capable of identifying and quantifying trace levels of AHLs in various wastewater treatment systems and can help us better understand the mechanisms of AHL-mediated quroum sensing in various wastewater treatment systems.
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Affiliation(s)
- Shujuan Huang
- Centre for Water Research, Department of Civil & Environmental Engineering, National University of Singapore, 1 Engineering Drive 2, 117576, Singapore
| | - Hui Zhang
- NUS Environmental Research Institute, National University of Singapore, #02-01, T-Lab Building, 5A Engineering Drive 1, 117411, Singapore
| | - Tze Chiang Albert Ng
- Centre for Water Research, Department of Civil & Environmental Engineering, National University of Singapore, 1 Engineering Drive 2, 117576, Singapore
| | - Boyan Xu
- Centre for Water Research, Department of Civil & Environmental Engineering, National University of Singapore, 1 Engineering Drive 2, 117576, Singapore
| | - Xueqing Shi
- School of Environmental and Municipal Engineering, Qingdao University of Technology, 11 Fushun Road, Qingdao, 266033, PR China
| | - How Yong Ng
- Centre for Water Research, Department of Civil & Environmental Engineering, National University of Singapore, 1 Engineering Drive 2, 117576, Singapore; NUS Environmental Research Institute, National University of Singapore, #02-01, T-Lab Building, 5A Engineering Drive 1, 117411, Singapore.
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56
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Covalently and ionically, dually crosslinked chitosan nanoparticles block quorum sensing and affect bacterial cell growth on a cell-density dependent manner. J Colloid Interface Sci 2020; 578:171-183. [PMID: 32526521 DOI: 10.1016/j.jcis.2020.05.075] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 05/16/2020] [Accepted: 05/18/2020] [Indexed: 01/16/2023]
Abstract
In our efforts to improve the quality and stability of chitosan nanoparticles (NPs), we describe here a new type of chitosan NPs dually crosslinked with genipin and sodium tripolyphosphate (TPP) that display quorum quenching activity. These NPs were created using a simplified and robust procedure that resulted in improved physicochemical properties and enhanced stability. This procedure involves the covalent crosslinking of chitosan with genipin, followed by the formation of chitosan NPs by ionic gelation with TPP. We have optimized the conditions to obtain genipin pre-crosslinked nanoparticles (PC-NPs) with positive ς-potential (~ +30 mV), small diameter (~130 nm), and low size distributions (PdI = 0.1-0.2). PC-NPs present physicochemical properties that are comparable to those of other dually crosslinked chitosan NPs fabricated with different protocols. In contrast to previously characterized NPs, however, we found that PC-NPs strongly reduce the acyl homoserine lactone (AHL)-mediated quorum sensing response of an Escherichia coli fluorescent biosensor. Thus, PC-NPs combine, in a single design, the stability of dually crosslinked chitosan NPs and the quorum quenching activity of ionically crosslinked NPs. Similar to other chitosan NPs, the mode of action of PC-NPs is consistent with the existence of a "stoichiometric ratio" of NP/bacterium, at which the positive charge of the NPs counteracts the negative ς-potential of the bacterial envelope. Notably, we found that the time of the establishment of the "stoichiometric ratio" is a function of the NP concentration, implying that these NPs could be ideal for applications aiming to target of bacterial populations at specific cell densities. We are confident that our PC-NPs are up-and-coming candidates for the design of efficient anti-quorum sensing and a new generation antimicrobial strategies.
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57
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Hayek M, Baraquet C, Lami R, Blache Y, Molmeret M. The Marine Bacterium Shewanella woodyi Produces C 8-HSL to Regulate Bioluminescence. MICROBIAL ECOLOGY 2020; 79:865-881. [PMID: 31741007 DOI: 10.1007/s00248-019-01454-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Accepted: 10/16/2019] [Indexed: 06/10/2023]
Abstract
Quorum sensing (QS), a cell-to-cell communication system involved in the synchronization of bacterial behavior in a cell-density-dependent manner has been shown to control phenotypes such as luminescence, virulence, and biofilm formation. The marine strain, Shewanella woodyi MS32 has been identified as a luminous bacterium. Very little information is known on this bacterium, in particular if its luminescence and biofilm formation are controlled by QS. In this study, we have demonstrated that S. woodyi MS32 emits luminescence in planktonic and sessile conditions. The putative QS regulatory genes homologous to luxI and luxR identified in the S. woodyi MS32 genome, named swoI and swoR, are divergently transcribed and are not genetically linked to the lux operon in contrast with its closest parent Shewanella hanedai and with Aliivibrio fischeri. Interestingly, the phylogenetic analysis based on the SwoI and SwoR sequences shows that a separate horizontal gene transfer (HGT) occurred for the regulatory genes and for the lux operon. Functional analyses demonstrate that the swoI and swoR mutants were non-luminescent. Expression of lux genes was impaired in the QS regulatory mutants. N-octanoyl-L-homoserine lactone (C8-HSL) identified using liquid chromatography mass spectrometry in the wild-type strain (but not in ΔswoI) can induce S. woodyi luminescence. No significant difference has been detected between the wild-type and mutants on adhesion and biofilm formation in the conditions tested. Therefore, we have demonstrated that the luxCDABEG genes of S. woodyi MS32 are involved in luminescence emission and that the swoR/swoI genes, originated from a separate HGT, regulate luminescence through C8-HSL production.
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Affiliation(s)
- Mahmoud Hayek
- Laboratoire MAPIEM, EA4323, Université de Toulon, Avenue de l'université, BP 20132, 83957, La Garde Cedex, France
| | - Claudine Baraquet
- Laboratoire MAPIEM, EA4323, Université de Toulon, Avenue de l'université, BP 20132, 83957, La Garde Cedex, France
| | - Raphaël Lami
- Sorbonne Universités, CNRS, Laboratoire de Biodiversité et Biotechnologies Microbiennes (LBBM), Observatoire Océanologique, Banyuls-sur-Mer, France
| | - Yves Blache
- Laboratoire MAPIEM, EA4323, Université de Toulon, Avenue de l'université, BP 20132, 83957, La Garde Cedex, France
| | - Maëlle Molmeret
- Laboratoire MAPIEM, EA4323, Université de Toulon, Avenue de l'université, BP 20132, 83957, La Garde Cedex, France.
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58
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An alternative strategy to detect bacterial contamination in milk and water: a newly designed electrochemical biosensor. Eur Food Res Technol 2020. [DOI: 10.1007/s00217-020-03491-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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59
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Manson DE, O’Reilly MC, Nyffeler KE, Blackwell HE. Design, Synthesis, and Biochemical Characterization of Non-Native Antagonists of the Pseudomonas aeruginosa Quorum Sensing Receptor LasR with Nanomolar IC 50 Values. ACS Infect Dis 2020; 6:649-661. [PMID: 32037806 DOI: 10.1021/acsinfecdis.9b00518] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Quorum sensing (QS), a bacterial cell-to-cell communication system mediated by small molecules and peptides, has received significant interest as a potential target to block infection. The common pathogen Pseudomonas aeruginosa uses QS to regulate many of its virulence phenotypes at high cell densities, and the LasR QS receptor plays a critical role in this process. Small molecule tools that inhibit LasR activity would serve to illuminate its role in P. aeruginosa virulence, but we currently lack highly potent and selective LasR antagonists, despite considerable research in this area. V-06-018, an abiotic small molecule discovered in a high-throughput screen, represents one of the most potent known LasR antagonists but has seen little study since its initial report. Herein, we report a systematic study of the structure-activity relationships (SARs) that govern LasR antagonism by V-06-018. We synthesized a focused library of V-06-018 derivatives and evaluated the library for bioactivity using a variety of cell-based LasR reporter systems. The SAR trends revealed by these experiments allowed us to design probes with 10-fold greater potency than that of V-06-018 and 100-fold greater potency than other commonly used N-acyl-l-homoserine lactone (AHL)-based LasR antagonists, along with high selectivities for LasR. Biochemical experiments to probe the mechanism of antagonism by V-06-018 and its analogues support these compounds interacting with the native ligand-binding site in LasR and, at least in part, stabilizing an inactive form of the protein. The compounds described herein are the most potent and efficacious antagonists of LasR known and represent robust probes both for characterizing the mechanisms of LuxR-type QS and for chemical biology research in general in the growing QS field.
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Affiliation(s)
- Daniel E. Manson
- Department of Chemistry, University of Wisconsin−Madison, 110 University Ave., Madison, Wisconsin 53706 United States
| | - Matthew C. O’Reilly
- Department of Chemistry, University of Wisconsin−Madison, 110 University Ave., Madison, Wisconsin 53706 United States
| | - Kayleigh E. Nyffeler
- Department of Chemistry, University of Wisconsin−Madison, 110 University Ave., Madison, Wisconsin 53706 United States
| | - Helen E. Blackwell
- Department of Chemistry, University of Wisconsin−Madison, 110 University Ave., Madison, Wisconsin 53706 United States
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60
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Mukherji R, Zhang S, Chowdhury S, Stallforth P. Chimeric LuxR Transcription Factors Rewire Natural Product Regulation. Angew Chem Int Ed Engl 2020; 59:6192-6195. [PMID: 31943579 PMCID: PMC7187462 DOI: 10.1002/anie.201914449] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 12/12/2019] [Indexed: 01/17/2023]
Abstract
LuxR-type transcriptional activator proteins frequently regulate the expression of biosynthetic gene clusters (BGCs). With only a fraction of bacterial BGCs being expressed under standard culturing conditions, modulation of LuxRs would provide a powerful approach to activate silent clusters. We show that by exploiting the modular nature of LuxR proteins, it is possible to construct functional chimeric LuxRs, which enables both the rewiring of quorum sensing systems and the activation of silent BGCs. Importantly, our strategy allowed us to identify the novel natural product pseudomonol from a bacterium of the genus Pseudomonas.
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Affiliation(s)
- Ruchira Mukherji
- Independent Junior Research Group Chemistry of Microbial CommunicationLeibniz Institute for Natural Product Research and Infection BiologyHans Knöll Institute (HKI)Beutenbergstrasse 11a07745JenaGermany
| | - Shuaibing Zhang
- Independent Junior Research Group Chemistry of Microbial CommunicationLeibniz Institute for Natural Product Research and Infection BiologyHans Knöll Institute (HKI)Beutenbergstrasse 11a07745JenaGermany
| | - Somak Chowdhury
- Independent Junior Research Group Chemistry of Microbial CommunicationLeibniz Institute for Natural Product Research and Infection BiologyHans Knöll Institute (HKI)Beutenbergstrasse 11a07745JenaGermany
| | - Pierre Stallforth
- Independent Junior Research Group Chemistry of Microbial CommunicationLeibniz Institute for Natural Product Research and Infection BiologyHans Knöll Institute (HKI)Beutenbergstrasse 11a07745JenaGermany
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61
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Mukherji R, Zhang S, Chowdhury S, Stallforth P. Chimeric LuxR Transcription Factors Rewire Natural Product Regulation. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.201914449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Ruchira Mukherji
- Independent Junior Research Group Chemistry of Microbial CommunicationLeibniz Institute for Natural Product Research and Infection BiologyHans Knöll Institute (HKI) Beutenbergstrasse 11a 07745 Jena Germany
| | - Shuaibing Zhang
- Independent Junior Research Group Chemistry of Microbial CommunicationLeibniz Institute for Natural Product Research and Infection BiologyHans Knöll Institute (HKI) Beutenbergstrasse 11a 07745 Jena Germany
| | - Somak Chowdhury
- Independent Junior Research Group Chemistry of Microbial CommunicationLeibniz Institute for Natural Product Research and Infection BiologyHans Knöll Institute (HKI) Beutenbergstrasse 11a 07745 Jena Germany
| | - Pierre Stallforth
- Independent Junior Research Group Chemistry of Microbial CommunicationLeibniz Institute for Natural Product Research and Infection BiologyHans Knöll Institute (HKI) Beutenbergstrasse 11a 07745 Jena Germany
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62
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Complete Genome Sequence of Pseudomonas putida Strain TS312, Harboring an HdtS-Type N-Acyl-Homoserine Lactone Synthase, Isolated from a Paper Mill. Microbiol Resour Announc 2020; 9:9/13/e00055-20. [PMID: 32217673 PMCID: PMC7098896 DOI: 10.1128/mra.00055-20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
We report the complete genome sequence of Pseudomonas putida strain TS312, in the class of Gammaproteobacteria. The strain, isolated from a paper mill, harbors the hdtS gene, encoding N-acyl-homoserine lactone synthase. Deciphering the genome contributes to revealing the mechanisms of quorum sensing and associated biofilm formation in engineered systems. We report the complete genome sequence of Pseudomonas putida strain TS312, in the class of Gammaproteobacteria. The strain, isolated from a paper mill, harbors the hdtS gene, encoding N-acyl-homoserine lactone synthase. Deciphering the genome contributes to revealing the mechanisms of quorum sensing and associated biofilm formation in engineered systems.
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63
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Zhang Q, Queneau Y, Soulère L. Biological Evaluation and Docking Studies of New Carbamate, Thiocarbamate, and Hydrazide Analogues of Acyl Homoserine Lactones as Vibrio fischeri-Quorum Sensing Modulators. Biomolecules 2020; 10:biom10030455. [PMID: 32183409 PMCID: PMC7175117 DOI: 10.3390/biom10030455] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 03/06/2020] [Accepted: 03/11/2020] [Indexed: 01/25/2023] Open
Abstract
A series of carbamate, thiocarbamate, and hydrazide analogues of acylhomoserine lactones (AHLs) were synthesized and their ability to modulate Vibrio fischeri-quorum sensing was evaluated. The compounds in the series exhibit variable side chain length and the possible presence of a diversely substituted phenyl substituent. Biological evaluation on the Vibrio fischeri quorum sensing system revealed that the ethyl substituted carbamate (1) display a weak agonistic activity whereas compounds with longer chain length or benzyl substituents display significant antagonistic activity. The most active compounds in the series were the 4-nitrobenzyl carbamate and thiocarbamate 7 and 11 which exhibited an IC50 value of about 20 µM. These activities are in the range of other reported of AHL-structurally related quorum sensing (QS) inhibitors. Docking experiments conducted on the LuxR model showed that, compared to the natural ligand OHHL, the additional heteroatom of the carbamate group induces a new hydrogen bond with Tyr70 leading to a different global hydrogen-bond network. Tyr70 is an important residue in the binding site and is strictly conserved in the LuxR family. For the 4-nitrobenzyl carbamate and thiocarbamate analogues, the docking results highlight an additional hydrogen bond between the nitro group and Lys178. For hydrazide analogues, which are deprived of any activity, docking shows that the orientation of the carbonyl group is opposite as compared with the natural ligand, leading to the absence of a H-bond between the C=O with Tyr62. This suggests that, either this later interaction, or the influence of the C=O orientation on the overall ligand conformation, are essential for the biological activity.
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64
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Vesty EF, Whitbread AL, Needs S, Tanko W, Jones K, Halliday N, Ghaderiardakani F, Liu X, Cámara M, Coates JC. Cross-kingdom signalling regulates spore germination in the moss Physcomitrella patens. Sci Rep 2020; 10:2614. [PMID: 32054953 PMCID: PMC7018845 DOI: 10.1038/s41598-020-59467-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 01/17/2020] [Indexed: 01/10/2023] Open
Abstract
Plants live in close association with microorganisms that can have beneficial or detrimental effects. The activity of bacteria in association with flowering plants has been extensively analysed. Bacteria use quorum-sensing as a way of monitoring their population density and interacting with their environment. A key group of quorum sensing molecules in Gram-negative bacteria are the N-acylhomoserine lactones (AHLs), which are known to affect the growth and development of both flowering plants, including crops, and marine algae. Thus, AHLs have potentially important roles in agriculture and aquaculture. Nothing is known about the effects of AHLs on the earliest-diverging land plants, thus the evolution of AHL-mediated bacterial-plant/algal interactions is unknown. In this paper, we show that AHLs can affect spore germination in a representative of the earliest plants on land, the Bryophyte moss Physcomitrella patens. Furthermore, we demonstrate that sporophytes of some wild isolates of Physcomitrella patens are associated with AHL-producing bacteria.
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Affiliation(s)
- Eleanor F Vesty
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, UK.,University Centre Shrewsbury, Guildhall, Frankwell Quay, Shrewsbury, Shropshire, UK
| | - Amy L Whitbread
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, UK.,Karlsruhe Institute of Technology, Karlsruhe, Baden-Württemberg, Germany
| | - Sarah Needs
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, UK.,School of Life, Health and Chemical Sciences, Open University, Walton Hall, Kents Hill, Milton Keynes, UK
| | - Wesal Tanko
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, UK
| | - Kirsty Jones
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, UK
| | - Nigel Halliday
- National Biofilm Innovations Centre, University of Nottingham Biodiscovery Institute, School of Life Sciences, University of Nottingham, University Park, Nottingham, UK
| | | | - Xiaoguang Liu
- National Biofilm Innovations Centre, University of Nottingham Biodiscovery Institute, School of Life Sciences, University of Nottingham, University Park, Nottingham, UK.,Institute of Life Sciences, Jiangsu University, Zhenjiang, China
| | - Miguel Cámara
- National Biofilm Innovations Centre, University of Nottingham Biodiscovery Institute, School of Life Sciences, University of Nottingham, University Park, Nottingham, UK.
| | - Juliet C Coates
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, UK.
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65
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Pathania AS, Jana AK. Improvement in Production of Rhamnolipids Using Fried Oil with Hydrophilic Co-substrate by Indigenous Pseudomonas aeruginosa NJ2 and Characterizations. Appl Biochem Biotechnol 2020; 191:1223-1246. [PMID: 32036539 DOI: 10.1007/s12010-019-03221-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 12/05/2019] [Indexed: 12/01/2022]
Abstract
Commercialization of biosurfactant remained a challenge due to lack of structural variation and economical process using low-cost materials and low productivity. Improvement in production of biosurfactant using fried oil with hydrophilic co-substrate by an indigenous strain was studied. Microbe isolated from exhaust chimney condensate was screened for utilization of mixed carbon source and then identified as Pseudomonas aeruginosa NJ2 by 16S rDNA gene sequence. FTIR, HPLC, and NMR analyses confirmed that biosurfactant was rhamnolipids. Batch fermentation using mixed substrates improved the cell growth yield to 1.48 g/L (2.34 times) and product yield to 4.28 g/L (3.4 times) with maximum specific growth rate 0.1 h-1 (two times) and specific production rate 0.5 h-1 (13 times) due to higher cell density and direct synthesis of lipid and rhamnose moieties through central metabolic pathways of the two substrates. Increase in carrying capacity and coefficient value (two times) of logistic equation confirmed the significance of mixed substrates. The biosurfactant showed excellent surface active and thermo-chemical stability properties. Economical production of biosurfactant with high yield and productivity could be possible by isolation of mixed carbon source utilizing strain and optimization of waste substrates from oil/soapstock and sugar/corn syrup industries in media.
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Affiliation(s)
- Arun Singh Pathania
- Department of Biotechnology, Dr. B R Ambedkar National Institute of Technology Jalandhar, Jalandhar, Punjab, 144011, India
| | - Asim Kumar Jana
- Department of Biotechnology, Dr. B R Ambedkar National Institute of Technology Jalandhar, Jalandhar, Punjab, 144011, India.
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66
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Jayaprada T, Hu J, Zhang Y, Feng H, Shen D, Geekiyanage S, Yao Y, Wang M. The interference of nonylphenol with bacterial cell-to-cell communication. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2020; 257:113352. [PMID: 31672371 DOI: 10.1016/j.envpol.2019.113352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 10/04/2019] [Accepted: 10/04/2019] [Indexed: 06/10/2023]
Abstract
The interference of nonylphenol (NP) with humans and animals, especially in hormone systems, has been well-studied. There is rarely any record of its effect on bacteria, which dominate in various environments. In our study, we employed Pseudomonas aeruginosa PAO1 as a model microorganism and took its common lifestyle biofilm, mainly regulated by quorum sensing (QS), as a cut-in point to investigate the effect of NP (1, 5, 10 mg L-1) on bacteria. The results showed that more than 5 mg L-1 of NP did interfere with biofilm formation and affected bacterial QS. In detail, the LasI/R circuit, but not the RhlI/R circuit, was considerably obstructed. The decrease in lasI and lasR expression resulted in a significant reduction in N-3-oxo-dodecanoyl homoserine lactone (3OC12-HSL) signals and the downstream production of elastases. Docking results indicated the binding of NP with LasR protein, simulating the binding of 3OC12-HSL with LasR protein, which explained the obstruction of the LasIR circuit. We concluded that NP competed with 3OC12-HSL and blocked 3OC12-HSL binding with the LasR protein, resulting in a direct interference in bacterial biofilm formation. This is the first report of NP interference with bacterial signaling, which is not only helpful to understand the effect of NP on various ecosystems, but is also beneficial to enrich our knowledge of inter-kingdom communication.
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Affiliation(s)
- Thilini Jayaprada
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310012, China
| | - Jingming Hu
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310012, China
| | - Yunyun Zhang
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310012, China
| | - Huajun Feng
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310012, China; Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, Hangzhou 310012, China
| | - Dongsheng Shen
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310012, China; Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, Hangzhou 310012, China
| | - Sudarshanee Geekiyanage
- Department of Agricultural Biology, University of Ruhuna, Mapalana, Kamburupitiya, 81100, Sri Lanka
| | - Yanlai Yao
- Institute of Environment Resource, Soil and Fertilizer, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China
| | - Meizhen Wang
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310012, China; Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, Hangzhou 310012, China.
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67
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Xu B, Albert Ng TC, Huang S, Shi X, Ng HY. Feasibility of isolated novel facultative quorum quenching consortiums for fouling control in an AnMBR. WATER RESEARCH 2020; 114:151-180. [PMID: 31706123 DOI: 10.1016/j.watres.2017.02.006] [Citation(s) in RCA: 478] [Impact Index Per Article: 119.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Revised: 01/10/2017] [Accepted: 02/02/2017] [Indexed: 05/06/2023]
Abstract
Anaerobic membrane bioreactor (AnMBR) technology is being recognized as an appealing strategy for wastewater treatment, however, severity of membrane fouling inhibits its widespread implementations. This study engineered novel facultative quorum quenching consortiums (FQQs) coping with membrane fouling in AnMBRs with preliminary analysis for their quorum quenching (QQ) performances. Herein, Acyl-homoserine lactones (AHLs)-based quorum sensing (QS) in a lab-scale AnMBR initially revealed that N-Hexanoyl-dl-homoserine lactone (C6-HSL), N-Octanoyl-dl-homoserine lactone (C8-HSL) and N-Decanoyl-dl-homoserine lactone (C10-HSL) were the dominant AHLs in AnMBRs in this study. Three FQQs, namely, FQQ-C6, FQQ-C8 and FQQ-C10, were harvested after anaerobic screening of aerobic QQ consortiums (AeQQs) which were isolated by enrichment culture, aiming to degrade C6-HSL, C8-HSL and C10-HSL, respectively. Growth of FQQ-C6 and FQQ-C10 using AHLs as carbon source under anaerobic condition was significantly faster than those using acetate, congruously suggesting that their QQ performance will not be compromised in AnMBRs. All FQQs degraded a wide range of AHLs pinpointing their extensive QQ ability. FQQ-C6, FQQ-C8 and FQQ-C10 remarkably alleviated extracellular polymeric substances (EPS) production in a lab-scale AnMBR by 72.46%, 35.89% and 65.88%, respectively, and FQQ-C6 retarded membrane fouling of the AnMBR by 2 times. Bioinformatics analysis indicated that there was a major shift in dominant species from AeQQs to FQQs where Comamonas sp., Klebsiella sp., Stenotrophomonas sp. and Ochrobactrum sp. survived after anaerobic screening and were the majority in FQQs. High growth rate utilizing AHLs under anaerobic condition and enormous EPS retardation efficiency in FQQ-C6 and FQQ-C10 could be attributed to Comamonas sp.. These findings demonstrated that FQQs could be leveraged for QQ under anaerobic systems. We believe that this was the first work proposing a bacterial pool of facultative QQ candidates holding biotechnological promises for membrane fouling control in AnMBRs.
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Affiliation(s)
- Boyan Xu
- Centre for Water Research, Department of Civil and Environmental Engineering, National University of Singapore, 1 Engineering Drive 2, Singapore, 117576
| | - Tze Chiang Albert Ng
- Centre for Water Research, Department of Civil and Environmental Engineering, National University of Singapore, 1 Engineering Drive 2, Singapore, 117576
| | - Shujuan Huang
- Centre for Water Research, Department of Civil and Environmental Engineering, National University of Singapore, 1 Engineering Drive 2, Singapore, 117576
| | - Xueqing Shi
- School of Environmental and Municipal Engineering, Qingdao University of Technology, 11 Fushun Road, Qingdao, 266033, PR China
| | - How Yong Ng
- Centre for Water Research, Department of Civil and Environmental Engineering, National University of Singapore, 1 Engineering Drive 2, Singapore, 117576; National University of Singapore Environmental Research Institute, 5A Engineering Drive 1, 117411, Singapore.
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68
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Computational prediction of active sites and ligands in different AHL quorum quenching lactonases and acylases. J Biosci 2020. [DOI: 10.1007/s12038-020-0005-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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69
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Posevins D, Li MB, Svensson Grape E, Inge AK, Qiu Y, Bäckvall JE. Highly Diastereoselective Palladium-Catalyzed Oxidative Cascade Carbonylative Carbocyclization of Enallenols. Org Lett 2020; 22:417-421. [PMID: 31895577 DOI: 10.1021/acs.orglett.9b04134] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A palladium-catalyzed oxidative cascade carbonylative carbocyclization of enallenols was developed. Under mild reaction conditions, a range of cis-fused [5,5] bicyclic γ-lactones and γ-lactams with a 1,3-diene motif were obtained in good yields with high diastereoselectivity. The obtained lactone/lactam products are viable substrates for a stereoselective Diels-Alder reaction with N-phenylmaleimide, providing polycyclic compounds with increased molecular complexity.
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Affiliation(s)
- Daniels Posevins
- Department of Organic Chemistry, Arrhenius Laboratory , Stockholm University , SE-106 91 Stockholm , Sweden
| | - Man-Bo Li
- Department of Organic Chemistry, Arrhenius Laboratory , Stockholm University , SE-106 91 Stockholm , Sweden
| | - Erik Svensson Grape
- Department of Materials and Environmental Chemistry, Arrhenius Laboratory , Stockholm University , SE-106 91 Stockholm , Sweden
| | - A Ken Inge
- Department of Materials and Environmental Chemistry, Arrhenius Laboratory , Stockholm University , SE-106 91 Stockholm , Sweden
| | - Youai Qiu
- Department of Organic Chemistry, Arrhenius Laboratory , Stockholm University , SE-106 91 Stockholm , Sweden
| | - Jan-E Bäckvall
- Department of Organic Chemistry, Arrhenius Laboratory , Stockholm University , SE-106 91 Stockholm , Sweden
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70
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Nain Z, Adhikari UK, Abdulla F, Hossain N, Barman NC, Mansur FJ, Azakami H, Karim MM. Computational prediction of active sites and ligands in different AHL quorum quenching lactonases and acylases. J Biosci 2020; 45:26. [PMID: 32020908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
With the emergence of multidrug-resistant 'superbug', conventional treatments become obsolete. Quorum quenching (QQ), enzyme-dependent alteration of quorum sensing (QS), is now considered as a promising antimicrobial therapy because of its potentiality to impede virulence gene expression without resulting in growth inhibition and antibiotic resistance. In our study, we intended to compare between two major QQ enzyme groups (i.e., AHL lactonases and AHL acylases) in terms of their structural and functional aspects. The amino acid composition-based principal component analysis (PCA) suggested that probably there is no structural and functional overlapping between the two groups of enzymes as well as within the lactonase enzymes but the acylases may functionally be affected by one another. In subcellular localization analysis, we also found that most lactonases are cytoplasmic while acylases are periplasmic. Investigation on the secondary structural features showed random coil dominates over alpha-helix and beta-sheet in all evaluated enzymes. For structural comparison, the tertiary structures of the selected proteins were modelled and submitted to the PMDB database (Accession ID: PM0081007 to PM0081018). Interestingly, sequence alignment revealed the presence of several conserved domains important for functions in both protein groups. In addition, three amino acid residues, namely aspartic acid, histidine, and isoleucine, were common in the active sites of all protein models while most frequent ligands were found to be 3C7, FEO, and PAC. Importantly, binding interactions of predicted ligands were similar to that of native QS signal molecules. Furthermore, hydrogen bonds analysis suggested six proteins are more stable than others. We believe that the knowledge of this comparative study could be useful for further research in the development of QSbased universal antibacterial strategies.
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Affiliation(s)
- Zulkar Nain
- Department of Biotechnology and Genetic Engineering, Faculty of Biological Sciences, Islamic University, Kushtia 7003, Bangladesh
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71
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Jiang W, Zhou J, Ma AJ, Li D, Ma YY, Zhao DG, Hou SH, Lin JB, Zhang SY. A dienamine-mediated deconjugative addition/cyclization cascade of γ,γ-disubstituted enals with carboxylic acid-activated enones: a rapid access to highly functionalized γ-lactones. Org Chem Front 2020. [DOI: 10.1039/c9qo01367a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
An aminocatalytic deconjugative addition/cyclization cascade of γ,γ-disubstituted enals with carboxylic acid-activated enones was realized, giving rise to highly functionalized γ-lactones with excellent enantioselectivities.
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Affiliation(s)
- Wei Jiang
- School of Biotechnology and Health Sciences
- International Healthcare Innovation Institute
- Wuyi University
- Jiangmen 529020
- China
| | - Jia Zhou
- Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs
- School of Chemistry and Chemical Engineering
- Shanghai Jiao Tong University
- Shanghai 200240
- China
| | - Ai-Jun Ma
- School of Biotechnology and Health Sciences
- International Healthcare Innovation Institute
- Wuyi University
- Jiangmen 529020
- China
| | - Dongli Li
- School of Biotechnology and Health Sciences
- International Healthcare Innovation Institute
- Wuyi University
- Jiangmen 529020
- China
| | - Yan-Yan Ma
- School of Biotechnology and Health Sciences
- International Healthcare Innovation Institute
- Wuyi University
- Jiangmen 529020
- China
| | - Deng-Gao Zhao
- School of Biotechnology and Health Sciences
- International Healthcare Innovation Institute
- Wuyi University
- Jiangmen 529020
- China
| | - Si-Hua Hou
- Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs
- School of Chemistry and Chemical Engineering
- Shanghai Jiao Tong University
- Shanghai 200240
- China
| | - Jun-Bing Lin
- Shaanxi Key Laboratory of Chemical Reaction Engineering
- College of Chemistry and Chemical Engineering
- Yan'an University
- Yan'an 716000
- China
| | - Shu-Yu Zhang
- School of Biotechnology and Health Sciences
- International Healthcare Innovation Institute
- Wuyi University
- Jiangmen 529020
- China
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72
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Ye T, Zhou T, Fan X, Bhatt P, Zhang L, Chen S. Acinetobacter lactucae Strain QL-1, a Novel Quorum Quenching Candidate Against Bacterial Pathogen Xanthomonas campestris pv. campestris. Front Microbiol 2019; 10:2867. [PMID: 31921047 PMCID: PMC6929412 DOI: 10.3389/fmicb.2019.02867] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2019] [Accepted: 11/27/2019] [Indexed: 11/16/2022] Open
Abstract
Quorum sensing (QS) is a cell–cell communication mechanism among bacterial populations that is regulated through gene expression in response to cell density. The pathogenicity of Xanthomonas campestris pv. campestris (Xcc) is modulated by the diffusible signal factor (DSF)-mediated QS system. DSF is widely conserved in a variety of gram-negative bacterial pathogens. In this study, DSF-degrading bacteria and their enzymes were thoroughly explored as a biocontrol agent against Xcc. The results indicated that a novel DSF-degrading bacterium, Acinetobacter lactucae QL-1, effectively attenuated Xcc virulence through quorum quenching. Lab-based experiments indicated that plants inoculated with QL-1 and Xcc had less tissue decay than those inoculated with Xcc alone. Co-inoculation of strains Xcc and QL-1 significantly reduced the incidence and severity of disease in plants. Similarly, the application of crude enzymes of strain QL-1 substantially reduced the disease severity caused by Xcc. The results showed that strain QL-1 and its enzymes possess promising potential, which could be further investigated to better protect plants from DSF-dependent pathogens.
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Affiliation(s)
- Tian Ye
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Integrative Microbiology Research Centre, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Laboratory of Lingnan Modern Agricultural Science and Technology, South China Agricultural University, Guangzhou, China
| | - Tian Zhou
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Integrative Microbiology Research Centre, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Laboratory of Lingnan Modern Agricultural Science and Technology, South China Agricultural University, Guangzhou, China
| | - Xinghui Fan
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Integrative Microbiology Research Centre, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Laboratory of Lingnan Modern Agricultural Science and Technology, South China Agricultural University, Guangzhou, China
| | - Pankaj Bhatt
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Integrative Microbiology Research Centre, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Laboratory of Lingnan Modern Agricultural Science and Technology, South China Agricultural University, Guangzhou, China
| | - Lianhui Zhang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Integrative Microbiology Research Centre, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Laboratory of Lingnan Modern Agricultural Science and Technology, South China Agricultural University, Guangzhou, China
| | - Shaohua Chen
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Integrative Microbiology Research Centre, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Laboratory of Lingnan Modern Agricultural Science and Technology, South China Agricultural University, Guangzhou, China
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73
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A CsrA-Binding, trans-Acting sRNA of Coxiella burnetii Is Necessary for Optimal Intracellular Growth and Vacuole Formation during Early Infection of Host Cells. J Bacteriol 2019; 201:JB.00524-19. [PMID: 31451541 DOI: 10.1128/jb.00524-19] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 08/17/2019] [Indexed: 11/20/2022] Open
Abstract
Coxiella burnetii is an obligate intracellular gammaproteobacterium and zoonotic agent of Q fever. We previously identified 15 small noncoding RNAs (sRNAs) of C. burnetii One of them, CbsR12 (Coxiella burnetii small RNA 12), is highly transcribed during axenic growth and becomes more prominent during infection of cultured mammalian cells. Secondary structure predictions of CbsR12 revealed four putative CsrA-binding sites in stem loops with consensus AGGA/ANGGA motifs. We subsequently determined that CbsR12 binds to recombinant C. burnetii CsrA-2, but not CsrA-1, proteins in vitro Moreover, through a combination of in vitro and cell culture assays, we identified several in trans mRNA targets of CbsR12. Of these, we determined that CbsR12 binds and upregulates translation of carA transcripts coding for carbamoyl phosphate synthetase A, an enzyme that catalyzes the first step of pyrimidine biosynthesis. In addition, CbsR12 binds and downregulates translation of metK transcripts coding for S-adenosylmethionine synthetase, a component of the methionine cycle. Furthermore, we found that CbsR12 binds to and downregulates the quantity of cvpD transcripts, coding for a type IVB effector protein, in mammalian cell culture. Finally, we found that CbsR12 is necessary for expansion of Coxiella-containing vacuoles and affects growth rates in a dose-dependent manner in the early phase of infecting THP-1 cells. This is the first characterization of a trans-acting sRNA of C. burnetii and the first example of a bacterial sRNA that regulates both CarA and MetK synthesis. CbsR12 is one of only a few identified trans-acting sRNAs that interacts with CsrA.IMPORTANCE Regulation of metabolism and virulence in C. burnetii is not well understood. Here, we show that C. burnetii small RNA 12 (CbsR12) is highly transcribed in the metabolically active large-cell variant compared to the nonreplicative small-cell variant. We show that CbsR12 directly regulates several genes involved in metabolism, along with a type IV effector gene, in trans In addition, we demonstrate that CbsR12 binds to CsrA-2 in vitro and induces autoaggregation and biofilm formation when transcribed ectopically in Escherichia coli, consistent with other CsrA-sequestering sRNAs. These results implicate CbsR12 in the indirect regulation of a number of genes via CsrA-mediated regulatory activities. The results also support CbsR12 as a crucial regulatory component early on in a mammalian cell infection.
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74
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Shin D, Gorgulla C, Boursier ME, Rexrode N, Brown EC, Arthanari H, Blackwell HE, Nagarajan R. N-Acyl Homoserine Lactone Analog Modulators of the Pseudomonas aeruginosa Rhll Quorum Sensing Signal Synthase. ACS Chem Biol 2019; 14:2305-2314. [PMID: 31545595 DOI: 10.1021/acschembio.9b00671] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Virulence in the Gram-negative pathogen Pseudomonas aeruginosa relies in part on the efficient functioning of two LuxI/R dependent quorum sensing (QS) cascades, namely, the LasI/R and RhlI/R systems that generate and respond to N-(3-oxo)-dodecanoyl-l-homoserine lactone and N-butyryl-l-homoserine lactone, respectively. The two acyl homoserine lactone (AHL) synthases, LasI and RhlI, use 3-oxododecanoyl-ACP and butyryl-ACP, respectively, as the acyl-substrates to generate the corresponding autoinducer signals for the bacterium. Although AHL synthases represent excellent targets for developing QS modulators in P. aeruginosa, and in other related bacteria, the identification of potent and signal synthase specific inhibitors has represented a significant technical challenge. In the current study, we sought to test the utility of AHL analogs as potential modulators of an AHL synthase and selected RhlI in P. aeruginosa as an initial target. We systematically varied the chemical functionalities of the AHL headgroup, acyl chain tail, and head-to-tail linkage to construct a small library of signal analogs and evaluated them for RhlI modulatory activity. Although the native N-butyryl-l-homoserine lactone did not inhibit RhlI, we discovered that several of our long-chain, unsubstituted acyl-d-homoserine lactones and acyl-d-homocysteine thiolactones inhibited while a few of the 3-oxoacyl-chain counterparts activated the enzyme. Additional mechanistic investigations with acyl-substrate analogs and docking experiments with AHL analogs revealed two distinct inhibitor and activator binding pockets in the enzyme. This study provides the first evidence of the yet untapped potential of AHL analogs as signal synthase modulators of QS pathways.
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Affiliation(s)
- Daniel Shin
- Department of Chemistry and Biochemistry, Boise State University, 1910 University Dr., Boise, Idaho 83725, United States
| | - Christoph Gorgulla
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Ave, Boston, Massachusetts 02115, United States
- Department of Physics, Harvard University, 17 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - Michelle E. Boursier
- Department of Chemistry, University of Wisconsin—Madison, 1101 University Ave, Madison, Wisconsin 53706, United States
| | - Neilson Rexrode
- Department of Chemistry and Biochemistry, Boise State University, 1910 University Dr., Boise, Idaho 83725, United States
| | - Eric C. Brown
- Department of Chemistry and Biochemistry, Boise State University, 1910 University Dr., Boise, Idaho 83725, United States
| | - Haribabu Arthanari
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Ave, Boston, Massachusetts 02115, United States
- Department of Cancer Biology, Dana Farber Cancer Institute, Boston, Massachusetts 02115, United States
| | - Helen E. Blackwell
- Department of Chemistry, University of Wisconsin—Madison, 1101 University Ave, Madison, Wisconsin 53706, United States
| | - Rajesh Nagarajan
- Department of Chemistry and Biochemistry, Boise State University, 1910 University Dr., Boise, Idaho 83725, United States
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75
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Gutiérrez‐Barranquero JA, Reen FJ, Parages ML, McCarthy R, Dobson ADW, O'Gara F. Disruption of N-acyl-homoserine lactone-specific signalling and virulence in clinical pathogens by marine sponge bacteria. Microb Biotechnol 2019; 12:1049-1063. [PMID: 29105344 PMCID: PMC6680641 DOI: 10.1111/1751-7915.12867] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 08/31/2017] [Indexed: 12/02/2022] Open
Abstract
In recent years, the marine environment has been the subject of increasing attention from biotechnological and pharmaceutical industries. A combination of unique physicochemical properties and spatial niche-specific substrates, in wide-ranging and extreme habitats, underscores the potential of the marine environment to deliver on functionally novel bioactivities. One such area of ongoing research is the discovery of compounds that interfere with the cell-cell signalling process called quorum sensing (QS). Described as the next generation of antimicrobials, these compounds can target virulence and persistence of clinically relevant pathogens, independent of any growth-limiting effects. Marine sponges are a rich source of microbial diversity, with dynamic populations in a symbiotic relationship. In this study, we have harnessed the QS inhibition (QSI) potential of marine sponge microbiota and through culture-based discovery have uncovered small molecule signal mimics that neutralize virulence phenotypes in clinical pathogens. This study describes for the first time a marine sponge Psychrobacter sp. isolate B98C22 that blocks QS signalling, while also reporting dual QS/QSI activity in the Pseudoalteromonas sp. J10 and ParacoccusJM45. Isolation of novel QSI activities has significant potential for future therapeutic development, of particular relevance in the light of the pending perfect storm of antibiotic resistance meeting antibiotic drug discovery decline.
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Affiliation(s)
- José A. Gutiérrez‐Barranquero
- BIOMERIT Research CentreSchool of MicrobiologyUniversity College CorkNational University of IrelandCorkIreland
- Present address:
Instituto de Hortofruticultura Subtropical y Mediterránea La MayoraDepartamento de MicrobiologíaFacultad de CienciasUniversidad de Málaga29071MálagaSpain
| | - F. Jerry Reen
- BIOMERIT Research CentreSchool of MicrobiologyUniversity College CorkNational University of IrelandCorkIreland
| | - María L. Parages
- BIOMERIT Research CentreSchool of MicrobiologyUniversity College CorkNational University of IrelandCorkIreland
- Present address:
Departamento de EcologíaFacultad de CienciasUniversidad de Málaga29071MálagaSpain
| | - Ronan McCarthy
- BIOMERIT Research CentreSchool of MicrobiologyUniversity College CorkNational University of IrelandCorkIreland
| | - Alan D. W. Dobson
- School of MicrobiologyUniversity College CorkNational University of IrelandCorkIreland
| | - Fergal O'Gara
- BIOMERIT Research CentreSchool of MicrobiologyUniversity College CorkNational University of IrelandCorkIreland
- Human Microbiome ProgrammeSchool of Biomedical SciencesCurtin Health Innovation Research InstituteCurtin UniversityPerthWAAustralia
- Curtin Health Innovation Research Institute (CHIRI)Curtin UniversityPerthWAAustralia
- School of Biomedical SciencesFaculty of Health SciencesCurtin UniversityPerthWAAustralia
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76
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Yu Z, Yu D, Mao Y, Zhang M, Ding M, Zhang J, Wu S, Qiu J, Yin J. Identification and characterization of a LuxI/R-type quorum sensing system in Pseudoalteromonas. Res Microbiol 2019; 170:243-255. [DOI: 10.1016/j.resmic.2019.07.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 07/04/2019] [Accepted: 07/09/2019] [Indexed: 12/30/2022]
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77
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Huang Y, Xu X, Song Y, Yuan N, Yu X, Ji Y, Liu J, Jiang T, Yu Z. Structure and product relationship analysis of acyl homoserine lactone synthases among Ensifer adhaerens reveals distinct chromosome and plasmid origins. Biochem Biophys Res Commun 2019; 516:907-913. [PMID: 31272719 DOI: 10.1016/j.bbrc.2019.06.131] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Accepted: 06/23/2019] [Indexed: 11/25/2022]
Abstract
Despite the conservative DNA sequences among LuxI (Acyl Homoserine Lactones synthase gene) homologs, structure-product relationship of AHL synthase remains to be elucidated. In this study, through degenerate primers and in vitro expression methods, we collected the information of the gene sequences and AHL profiles from nine LuxIs among Ensifer adhaerens strains. The chromosome-encoded LuxI (C-LuxI) distinguished themselves from the plasmid-encoded ones (P-LuxI) not only in the DNA sequences, but also in AHL profiles. The C-LuxIs produced only C14-HSL, while the P-LuxIs produced predominantly C8-HSL and 3-oxo-C8-HSL. Sequence-product relationship analysis updated our recognition of the role of T140 (EsaI) in the 3-oxo-HSL production. Computational calculation based on 3D structures of these LuxIs revealed the linear relationship between the chain length and the affinity of amides to AHL synthase in C-LuxI, which was not found in the P-LuxI. We hereby proposed the linear docking affinity as a criterion for the prediction of long-chain AHL production by an AHL synthase. This study extends our understanding on the structure-product relationship of AHL synthases and revealed the distinct chromosome and plasmid origin of this enzyme among E. adhaerens.
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Affiliation(s)
- Yili Huang
- Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Department of Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China.
| | - Xinyi Xu
- Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Department of Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China
| | - Yao Song
- Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Department of Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China
| | - Nate Yuan
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
| | - Xionghui Yu
- Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Department of Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China
| | - Yuqian Ji
- Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Department of Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China
| | - Jiang Liu
- Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Department of Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China
| | - Tingting Jiang
- Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Department of Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China
| | - Zhiliang Yu
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China.
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78
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Ortiz-Castro R, López-Bucio J. Review: Phytostimulation and root architectural responses to quorum-sensing signals and related molecules from rhizobacteria. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2019; 284:135-142. [PMID: 31084866 DOI: 10.1016/j.plantsci.2019.04.010] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 03/29/2019] [Accepted: 04/11/2019] [Indexed: 05/05/2023]
Abstract
Bacteria rely on chemical communication to sense the environment and to retrieve information on their population densities. Accordingly, a vast repertoire of molecules is released, which synchronizes expression of genes, coordinates behavior through a process termed quorum-sensing (QS), and determines the relationships with eukaryotic species. Already identified QS molecules from Gram negative bacteria can be grouped into two main classes, N-acyl-L-homoserine lactones (AHLs) and cyclodipeptides (CDPs), with roles in biofilm formation, bacterial virulence or symbiotic interactions. Noteworthy, plants detect each of these molecules, change their own gene expression programs, re-configurate root architecture, and activate defense responses, improving in this manner their adaptation to natural and agricultural ecosystems. AHLs may act as alarm signals, pathogen and/or microbe-associated molecular patterns, whereas CDPs function as hormonal mimics for plants via their putative interactions with the auxin receptor Transport Inhibitor Response1 (TIR1). A major challenge is to identify the molecular pathways of QS-mediated crosstalk and the plant receptors and interacting proteins for AHLs, CDPs and related signals.
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Affiliation(s)
- Randy Ortiz-Castro
- Red de Estudios Moleculares Avanzados, Instituto de Ecología A. C., Carretera Antigua a Coatepec 351, El Haya, C. P. 91070 Xalapa, Veracruz, Mexico
| | - José López-Bucio
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Edificio B3, Ciudad Universitaria, C. P. 58030, Morelia, Michoacán, Mexico.
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79
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Maddela NR, Sheng B, Yuan S, Zhou Z, Villamar-Torres R, Meng F. Roles of quorum sensing in biological wastewater treatment: A critical review. CHEMOSPHERE 2019; 221:616-629. [PMID: 30665091 DOI: 10.1016/j.chemosphere.2019.01.064] [Citation(s) in RCA: 94] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 12/23/2018] [Accepted: 01/09/2019] [Indexed: 06/09/2023]
Abstract
Quorum sensing (QS) and quorum quenching (QQ) are increasingly reported in biological wastewater treatment processes because of their inherent roles in biofilm development, bacterial aggregation, granulation, colonization, and biotransformation of pollutants. As such, the fundamentals and ubiquitous nature of QS bacteria are critical for fully understanding the process of the wastewater treatment system. In this article, the details of QS-based strategies related to community behaviors and phenotypes in wastewater treatment systems were reviewed. The molecular aspects and coexistence of QS and QQ bacteria were also mentioned, which provide evidence that future wastewater treatment will indispensably rely on QS-based strategies. In addition, recent attempts focusing on the use of QQ for biofilm or biofouling control were also summarized. Nevertheless, there are still several challenges and knowledge gaps that warrant future targeted research on the ecological niche, abundance, and community of QS- and QQ-bacteria in environmental settings or engineered systems.
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Affiliation(s)
- Naga Raju Maddela
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, PR China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Guangzhou 510275, PR China; Facultad de Ciencias de la Salud, Universidad Técnica de Manabí, Portoviejo 130105, Ecuador
| | - Binbin Sheng
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, PR China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Guangzhou 510275, PR China
| | - Shasha Yuan
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, PR China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Guangzhou 510275, PR China
| | - Zhongbo Zhou
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, PR China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Guangzhou 510275, PR China
| | - Ronald Villamar-Torres
- Université de Montpellier, CIRAD, INRA, Montpellier SupAgro, Montpellier 34090, France; Facultad de Ingeniería Agronómica, Universidad Técnica de Manabí, Campus Experimental "La Teodomira", Santa Ana 131301, Ecuador
| | - Fangang Meng
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, PR China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Guangzhou 510275, PR China.
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80
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Sawano T, Yamamoto H. Enantioselective Epoxidation of β,γ-Unsaturated Carboxylic Acids by a Cooperative Binuclear Titanium Complex. ACS Catal 2019. [DOI: 10.1021/acscatal.9b00840] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Takahiro Sawano
- Molecular Catalyst Research Center, Chubu University, 1200, Matsumoto-cho, Kasugai, Aichi 487-8501, Japan
| | - Hisashi Yamamoto
- Molecular Catalyst Research Center, Chubu University, 1200, Matsumoto-cho, Kasugai, Aichi 487-8501, Japan
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81
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Ahmed SAKS, Rudden M, Smyth TJ, Dooley JSG, Marchant R, Banat IM. Natural quorum sensing inhibitors effectively downregulate gene expression of Pseudomonas aeruginosa virulence factors. Appl Microbiol Biotechnol 2019; 103:3521-3535. [PMID: 30852658 PMCID: PMC6449319 DOI: 10.1007/s00253-019-09618-0] [Citation(s) in RCA: 120] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 01/02/2019] [Accepted: 01/04/2019] [Indexed: 12/02/2022]
Abstract
At present, anti-virulence drugs are being considered as potential therapeutic alternatives and/or adjuvants to currently failing antibiotics. These drugs do not kill bacteria but inhibit virulence factors essential for establishing infection and pathogenesis through targeting non-essential metabolic pathways reducing the selective pressure to develop resistance. We investigated the effect of naturally isolated plant compounds on the repression of the quorum sensing (QS) system which is linked to virulence/pathogenicity in Pseudomonas aeruginosa. Our results show that trans-cinnamaldehyde (CA) and salicylic acid (SA) significantly inhibit expression of QS regulatory and virulence genes in P. aeruginosa PAO1 at sub-inhibitory levels without any bactericidal effect. CA effectively downregulated both the las and rhl QS systems with lasI and lasR levels inhibited by 13- and 7-fold respectively compared to 3- and 2-fold reductions with SA treatment, during the stationary growth phase. The QS inhibitors (QSI) also reduced the production of extracellular virulence factors with CA reducing protease, elastase and pyocyanin by 65%, 22% and 32%, respectively. The QSIs significantly reduced biofilm formation and concomitantly with repressed rhamnolipid gene expression, only trace amount of extracellular rhamnolipids were detected. The QSIs did not completely inhibit virulence factor expression and production but their administration significantly lowered the virulence phenotypes at both the transcriptional and extracellular levels. This study shows the significant inhibitory effect of natural plant-derived compounds on the repression of QS systems in P. aeruginosa.
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Affiliation(s)
- Syed A K S Ahmed
- School of Biomedical Sciences, Ulster University, Coleraine, BT52 1SA, UK
| | - Michelle Rudden
- Department of Biology, University of York, Wentworth, York, YO10 5DD, UK
| | - Thomas J Smyth
- School of Science, Institute of Technology Sligo, Sligo, Ireland
| | - James S G Dooley
- School of Biomedical Sciences, Ulster University, Coleraine, BT52 1SA, UK.
| | - Roger Marchant
- School of Biomedical Sciences, Ulster University, Coleraine, BT52 1SA, UK
| | - Ibrahim M Banat
- School of Biomedical Sciences, Ulster University, Coleraine, BT52 1SA, UK
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82
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Structural determinants driving homoserine lactone ligand selection in the Pseudomonas aeruginosa LasR quorum-sensing receptor. Proc Natl Acad Sci U S A 2018; 116:245-254. [PMID: 30559209 DOI: 10.1073/pnas.1817239116] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Quorum sensing is a cell-cell communication process that bacteria use to orchestrate group behaviors. Quorum sensing is mediated by signal molecules called autoinducers. Autoinducers are often structurally similar, raising questions concerning how bacteria distinguish among them. Here, we use the Pseudomonas aeruginosa LasR quorum-sensing receptor to explore signal discrimination. The cognate autoinducer, 3OC12 homoserine lactone (3OC12HSL), is a more potent activator of LasR than other homoserine lactones. However, other homoserine lactones can elicit LasR-dependent quorum-sensing responses, showing that LasR displays ligand promiscuity. We identify mutants that alter which homoserine lactones LasR detects. Substitution at residue S129 decreases the LasR response to 3OC12HSL, while enhancing discrimination against noncognate autoinducers. Conversely, the LasR L130F mutation increases the potency of 3OC12HSL and other homoserine lactones. We solve crystal structures of LasR ligand-binding domains complexed with noncognate autoinducers. Comparison with existing structures reveals that ligand selectivity/sensitivity is mediated by a flexible loop near the ligand-binding site. We show that LasR variants with modified ligand preferences exhibit altered quorum-sensing responses to autoinducers in vivo. We suggest that possessing some ligand promiscuity endows LasR with the ability to optimally regulate quorum-sensing traits.
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83
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Characterization of LuxI/LuxR and their regulation involved in biofilm formation and stress resistance in fish spoilers Pseudomonas fluorescens. Int J Food Microbiol 2018; 297:60-71. [PMID: 30884254 DOI: 10.1016/j.ijfoodmicro.2018.12.011] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 12/11/2018] [Accepted: 12/13/2018] [Indexed: 12/22/2022]
Abstract
Quorum sensing (QS) is crucial for adaption and development of foodborne bacteria in diverse environments. Pseudomonas fluorescens PF07 with QS mediated acylated homoserine lactones (AHLs) activity was isolated from spoiled large yellow croaker (Pseudosciaena crocea). In this study AHL-mediated QS system was characterized and their roles in biofilm formation, motility, stress response and spoilage of P. fluorescens were evaluated. A LuxI/LuxR homolog consisting of a conserved AHL synthase gene (luxI) and a transcriptional regulator gene (luxR) was identified in the strain. Two in-frame deletion mutants of luxI and luxR, ∆luxI and ∆luxR, were constructed to explore their QS signaling function in P. fluorescens. Three types of AHLs were detected in PF07 culture by LC-MS/MS, and N-butanoyl-l-homoserine lactone (C4-HSL) was a major signal molecule. The C4-HSL activities was almost abolished in ∆luxI, and decreased greatly in ∆luxR. Compared with wild type (WT) strain, both ∆luxI and ∆luxR showed the significant decrease of biofilm biomass and expolysaccharide production, resulting in thinner and incompact biofilm structure, but promoted swimming motility. The resistance of P. fluorescens to H2O2, heat, NaCl and crystal violet apparently declined in two mutants compared to WT. Spoilage factors, siderophore and protease, apparently attenuated due to deletion of luxI or luxR gene, while the growth and TVB-N production did not differ. Furthermore, the changes of the biofilm formation, motility and protease in ∆luxI strain were partially restored by the exogenous C4-HSL. In agreement with the effect of two mutants on various phenotypes, the transcriptions of alg, lapA, flgA, rpoS, and aprX were significantly down-regulated, and flgA was up-regulated in ∆luxI and ∆luxR. Therefore, the present study highlighted that the co-operation of LuxI/LuxR homolog was an important QS regulator in biofilm formation, motility and spoilage potential, and hinted its positive regulation of stress resistance with RpoS in P. fluorescens.
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84
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Zhu Z, Wang Z, Li S, Yuan X. Antimicrobial strategies for urinary catheters. J Biomed Mater Res A 2018; 107:445-467. [PMID: 30468560 DOI: 10.1002/jbm.a.36561] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 09/03/2018] [Accepted: 10/04/2018] [Indexed: 01/12/2023]
Abstract
Over 75% of hospital-acquired or nosocomial urinary tract infections are initiated by urinary catheters, which are used during the treatment of 16% of hospitalized patients. Taking the United States as an example, the costs of catheter-associated urinary tract infections (CAUTI) are in excess of $451 million dollars/year. The biofilm formation by pathogenic microbes that protects pathogens from host immune defense and antimicrobial agents is the leading cause for CAUTI. Thus, tremendous efforts have been devoted to antimicrobial coating for urinary catheters in the past few decades, and it has been demonstrated to be one of the most direct and efficient strategies to reduce infections. In this article, we briefly summarize the current methods for preparation of antimicrobial coatings based on different stages in the biofilm formation, highlight recent progress in the urinary catheter coating material design and selection, discuss approaches to improving their long-term antimicrobial efficacy, biocompatibility, multidrug resistance and recurrent infections, and finally outline future requirements and prospects in antimicrobial coating material design. The scope of the works surveyed is confined to antimicrobial urinary catheters. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 445-467, 2019.
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Affiliation(s)
- Zhiling Zhu
- School of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao, Shandong 266042, China
| | - Ziping Wang
- Shandong Peninsula Engineering Research Center of Comprehensive Brine Utilization, Weifang University of Science and Technology, Weifang, Shandong 262700, China
| | - Siheng Li
- Department of Chemistry, University of Houston, Houston, Texas 77204, USA
| | - Xun Yuan
- School of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao, Shandong 266042, China
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85
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Recent developments in biofouling control in membrane bioreactors for domestic wastewater treatment. Sep Purif Technol 2018. [DOI: 10.1016/j.seppur.2018.06.004] [Citation(s) in RCA: 100] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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86
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Li MB, Inge AK, Posevins D, Gustafson KPJ, Qiu Y, Bäckvall JE. Chemodivergent and Diastereoselective Synthesis of γ-Lactones and γ-Lactams: A Heterogeneous Palladium-Catalyzed Oxidative Tandem Process. J Am Chem Soc 2018; 140:14604-14608. [DOI: 10.1021/jacs.8b09562] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Man-Bo Li
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
| | - A. Ken Inge
- Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Daniels Posevins
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Karl P. J. Gustafson
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Youai Qiu
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Jan-E. Bäckvall
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
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87
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Kher HL, Krishnan T, Letchumanan V, Hong KW, How KY, Lee LH, Tee KK, Yin WF, Chan KG. Characterization of quorum sensing genes and N-acyl homoserine lactones in Citrobacter amalonaticus strain YG6. Gene 2018; 684:58-69. [PMID: 30321658 DOI: 10.1016/j.gene.2018.10.031] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 07/27/2018] [Accepted: 10/11/2018] [Indexed: 11/26/2022]
Abstract
In the phylum of Proteobacteria, quorum sensing (QS) system is widely driven by synthesis and response of N-acyl homoserine lactone (AHL) signalling molecules. AHL is synthesized by LuxI homologue and sensed by LuxR homologue. Once the AHL concentration achieves a threshold level, it triggers the regulation of target genes. In this study, QS activity of Citrobacter amalonaticus strain YG6 which was isolated from clams was investigated. In order to characterise luxI/R homologues, the genome of C. amalonaticus strain YG6 (4.95 Mbp in size) was sequenced using Illumina MiSeq sequencer. Through in silico analysis, a pair of canonical luxI/R homologues and an orphan luxR homologue were identified and designated as camI, camR, and camR2, respectively. A putative lux box was identified at the upstream of camI. The camI gene was cloned and overexpressed in E. coli BL21 (DE3)pLysS. High-resolution triple quadrupole liquid chromatography mass spectrometry (LC-MS/MS) analysis verified that the CamI is a functional AHL synthase which produced multiple AHL species, namely N‑butyryl‑l‑homoserine lactone (C4-HSL), N‑hexanoyl‑l‑homoserine lactone (C6-HSL), N‑octanoyl‑l‑homoserine lactone (C8-HSL), N‑tetradecanoyl‑l‑homoserine lactone (C14-HSL) and N‑hexadecanoyl‑l‑homoserine lactone (C16-HSL) in C. amalonaticus strain YG6 and camI gene in recombinant E. coli BL21(DE3)pLysS. To our best knowledge, this is the first functional study report of camI as well as the first report describing the production of C14-HSL by C. amalonaticus.
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Affiliation(s)
- Heng-Leong Kher
- Institute of Graduate Studies, University of Malaya, Kuala Lumpur 50603, Malaysia
| | - Thiba Krishnan
- Division of Genetics and Molecular Biology, Institute of Biological Science, Faculty of Science, University of Malaya, Kuala Lumpur 50603, Malaysia
| | - Vengadesh Letchumanan
- Division of Genetics and Molecular Biology, Institute of Biological Science, Faculty of Science, University of Malaya, Kuala Lumpur 50603, Malaysia; Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Jalan Lagoon Selatan, 47500 Bandar Sunway, Selangor, Malaysia
| | - Kar-Wai Hong
- Division of Genetics and Molecular Biology, Institute of Biological Science, Faculty of Science, University of Malaya, Kuala Lumpur 50603, Malaysia
| | - Kah-Yan How
- Division of Genetics and Molecular Biology, Institute of Biological Science, Faculty of Science, University of Malaya, Kuala Lumpur 50603, Malaysia
| | - Learn-Han Lee
- Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Jalan Lagoon Selatan, 47500 Bandar Sunway, Selangor, Malaysia.
| | - Kok-Keng Tee
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia.
| | - Wai-Fong Yin
- Division of Genetics and Molecular Biology, Institute of Biological Science, Faculty of Science, University of Malaya, Kuala Lumpur 50603, Malaysia
| | - Kok-Gan Chan
- Division of Genetics and Molecular Biology, Institute of Biological Science, Faculty of Science, University of Malaya, Kuala Lumpur 50603, Malaysia; International Genome Centre, Jiangsu University, Zhenjiang, China.
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88
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The PqsE and RhlR proteins are an autoinducer synthase-receptor pair that control virulence and biofilm development in Pseudomonas aeruginosa. Proc Natl Acad Sci U S A 2018; 115:E9411-E9418. [PMID: 30224496 PMCID: PMC6176596 DOI: 10.1073/pnas.1814023115] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The human pathogen Pseudomonas aeruginosa is the leading cause of hospital-acquired infections and, moreover, is resistant to commonly used antibiotics. P. aeruginosa uses the cell-to-cell communication process called quorum sensing (QS) to control virulence. QS relies on production and response to extracellular signaling molecules called autoinducers. Here, we identify the PqsE enzyme as the synthase of an autoinducer that activates the QS receptor RhlR. We show that the PqsE-derived autoinducer is the key molecule driving P. aeruginosa biofilm formation and virulence in animal models of infection. We propose that PqsE and RhlR constitute a QS synthase–receptor pair, and that this system can be targeted for antimicrobial development. Pseudomonas aeruginosa is a leading cause of life-threatening nosocomial infections. Many virulence factors produced by P. aeruginosa are controlled by the cell-to-cell communication process called quorum sensing (QS). QS depends on the synthesis, release, and groupwide response to extracellular signaling molecules called autoinducers. P. aeruginosa possesses two canonical LuxI/R-type QS systems, LasI/R and RhlI/R, that produce and detect 3OC12-homoserine lactone and C4-homoserine lactone, respectively. Previously, we discovered that RhlR regulates both RhlI-dependent and RhlI-independent regulons, and we proposed that an alternative ligand functions together with RhlR to control the target genes in the absence of RhlI. Here, we report the identification of an enzyme, PqsE, which is the alternative-ligand synthase. Using biofilm analyses, reporter assays, site-directed mutagenesis, protein biochemistry, and animal infection studies, we show that the PqsE-produced alternative ligand is the key autoinducer that promotes virulence gene expression. Thus, PqsE can be targeted for therapeutic intervention. Furthermore, this work shows that PqsE and RhlR function as a QS-autoinducer synthase–receptor pair that drives group behaviors in P. aeruginosa.
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89
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Huang X, Zhu J, Cai Z, Lao Y, Jin H, Yu K, Zhang B, Zhou J. Profiles of quorum sensing (QS)-related sequences in phycospheric microorganisms during a marine dinoflagellate bloom, as determined by a metagenomic approach. Microbiol Res 2018; 217:1-13. [PMID: 30384903 DOI: 10.1016/j.micres.2018.08.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2018] [Revised: 08/26/2018] [Accepted: 08/29/2018] [Indexed: 01/09/2023]
Abstract
The complicated relationships among environmental microorganisms are regulated by quorum sensing (QS). Understanding QS-based signals could shed light on the interactions between microbial communities in certain environments. Although QS characteristics have been widely discussed, few studies have been conducted on the role of QS in phycospheric microorganisms. Here, we used metagenomics to examine the profile of AI-1 (AinS, HdtS, LuxI) and AI-2 (LuxS) autoinducers from a deeply sequenced microbial database, obtained from a complete dinoflagellate bloom. A total of 3001 putative AI-1 homologs and 130 AI-2 homologs were identified. The predominant member among the AI groups was HdtS. The abundance of HdtS, AinS, and LuxS increased as the bloom developed, whereas the abundance of LuxI showed the opposite trend. Phylogenetic analysis suggested that HdtS and LuxI synthase originated mainly from alpha-, beta-, and gamma-Proteobacteria, whereas AinS synthase originated solely from Vibrionales. In comparison to AI-1, the sequences related to AI-2 (LuxS) demonstrated a much wider taxonomic coverage. Some significant correlations were found between dominant species and QS signals. In addition to the QS, we also performed parallel analysis of the quorum quenching (QQ) sequences. In comparison to QS, the relative abundance of QQ signals was lower; however, an obvious frequency correlation was observed. These results suggested that QS and QQ signals co-participate in regulating microbial communities during an algal bloom. These data helped to reveal the characteristic behavior of algal symbiotic bacteria, and facilitated a better understanding of microbial dynamics during an algal bloom event from a chemical ecological perspective.
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Affiliation(s)
- Xinqing Huang
- Shenzhen Public Platform for Screening and Application of Marine Microbial Resources, The Graduate School at Shenzhen, Tsinghua University, Guangdong Province, Shenzhen, China
| | - Jianming Zhu
- Shenzhen Public Platform for Screening and Application of Marine Microbial Resources, The Graduate School at Shenzhen, Tsinghua University, Guangdong Province, Shenzhen, China
| | - Zhonghua Cai
- Shenzhen Public Platform for Screening and Application of Marine Microbial Resources, The Graduate School at Shenzhen, Tsinghua University, Guangdong Province, Shenzhen, China
| | - Yongmin Lao
- Shenzhen Public Platform for Screening and Application of Marine Microbial Resources, The Graduate School at Shenzhen, Tsinghua University, Guangdong Province, Shenzhen, China
| | - Hui Jin
- Shenzhen Public Platform for Screening and Application of Marine Microbial Resources, The Graduate School at Shenzhen, Tsinghua University, Guangdong Province, Shenzhen, China
| | - Ke Yu
- The Division of Environment and Energy, Graduate School at Shenzhen, Peking University, Guangdong Province, Shenzhen, China
| | - Boya Zhang
- The Division of Environment and Energy, Graduate School at Shenzhen, Peking University, Guangdong Province, Shenzhen, China
| | - Jin Zhou
- Shenzhen Public Platform for Screening and Application of Marine Microbial Resources, The Graduate School at Shenzhen, Tsinghua University, Guangdong Province, Shenzhen, China.
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90
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O'Reilly MC, Dong SH, Rossi FM, Karlen KM, Kumar RS, Nair SK, Blackwell HE. Structural and Biochemical Studies of Non-native Agonists of the LasR Quorum-Sensing Receptor Reveal an L3 Loop "Out" Conformation for LasR. Cell Chem Biol 2018; 25:1128-1139.e3. [PMID: 30033130 DOI: 10.1016/j.chembiol.2018.06.007] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Revised: 02/27/2018] [Accepted: 06/20/2018] [Indexed: 02/06/2023]
Abstract
Chemical strategies to block quorum sensing (QS) could provide a route to attenuate virulence in bacterial pathogens. Considerable research has focused on this approach in Pseudomonas aeruginosa, which uses the LuxR-type receptor LasR to regulate much of its QS network. Non-native ligands that antagonize LasR have been developed, yet we have little understanding of the mode by which these compounds interact with LasR and alter its function, as the receptor is unstable in their presence. Herein, we report an approach to circumvent this challenge through the study of a series of synthetic LasR agonists with varying levels of potency. Structural investigations of these ligands with the LasR ligand-binding domain reveal that certain agonists can enforce a conformation that deviates from that observed for other, often more potent agonists. These results, when combined with cell-based and biophysical analyses, suggest a functional model for LasR that could guide future ligand design.
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Affiliation(s)
- Matthew C O'Reilly
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706, USA
| | - Shi-Hui Dong
- Department of Biochemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, IL 61801, USA
| | - Francis M Rossi
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706, USA
| | - Kaleigh M Karlen
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706, USA
| | - Rohan S Kumar
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706, USA
| | - Satish K Nair
- Department of Biochemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, IL 61801, USA.
| | - Helen E Blackwell
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706, USA.
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91
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Potrykus M, Hugouvieux‐Cotte‐Pattat N, Lojkowska E. Interplay of classic Exp and specific Vfm quorum sensing systems on the phenotypic features of Dickeya solani strains exhibiting different virulence levels. MOLECULAR PLANT PATHOLOGY 2018; 19:1238-1251. [PMID: 28921772 PMCID: PMC6638156 DOI: 10.1111/mpp.12614] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 08/10/2017] [Accepted: 09/14/2017] [Indexed: 05/31/2023]
Abstract
Bacteria from the genus Dickeya cause severe symptoms on numerous economically important plants. Dickeya solani is the Dickeya species most frequently found on infected potato plants in Europe. D. solani strains from different countries show high genetic homogeneity, but significant differences in their virulence level. Dickeya species possess two quorum sensing (QS) mechanisms: the Exp system based on classic N-acyl-homoserine lactone (AHL) signals and a specific system depending on the production and perception of a molecule of unknown structure, Virulence Factor Modulating (VFM). To study the interplay between these two QS systems, five D. solani strains exhibiting different virulence levels were selected. Mutants were constructed by inactivating genes coding for each QS system. Double mutants were obtained by simultaneous inactivation of genes coding for both QS systems. Most of the D. solani mutants showed an attenuation of chicory maceration and a decreased production of plant cell wall-degrading enzymes (PCWDEs) and motility, but to different degrees depending on the strain. The VFM-QS system seems to regulate virulence in both D. solani and Dickeya dadantii, but the AHL-QS system has greater effects in D. solani than in D. dadantii. The inactivation of both QS systems in D. solani did not reveal any additive effect on the tested features. The inactivation of vfm genes generally has a more dominant effect relative to that of exp genes. Thus, VFM- and AHL-QS systems do not work in synergy to modulate the production of diverse virulence factors and the ability to macerate plant tissue.
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Affiliation(s)
- Marta Potrykus
- Department of Biotechnology, Intercollegiate Faculty of BiotechnologyUniversity of Gdansk and Medical University of Gdansk, Abrahama 58, 80–307GdanskPoland
| | - Nicole Hugouvieux‐Cotte‐Pattat
- UMR5240 Microbiologie Adaptation et PathogénieUniversité Lyon, CNRS, INSA Lyon, Université Claude Bernard Lyon 1F–69622 VilleurbanneFrance
| | - Ewa Lojkowska
- Department of Biotechnology, Intercollegiate Faculty of BiotechnologyUniversity of Gdansk and Medical University of Gdansk, Abrahama 58, 80–307GdanskPoland
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92
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Wysoczynski-Horita CL, Boursier ME, Hill R, Hansen K, Blackwell HE, Churchill MEA. Mechanism of agonism and antagonism of the Pseudomonas aeruginosa quorum sensing regulator QscR with non-native ligands. Mol Microbiol 2018; 108:240-257. [PMID: 29437248 DOI: 10.1111/mmi.13930] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/09/2018] [Indexed: 12/25/2022]
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen that uses the process of quorum sensing (QS) to coordinate the expression of many virulence genes. During quorum sensing, N-acyl-homoserine lactone (AHL) signaling molecules regulate the activity of three LuxR-type transcription factors, LasR, RhlR and QscR. To better understand P. aeruginosa QS signal reception, we examined the mechanism underlying the response of QscR to synthetic agonists and antagonists using biophysical and structural approaches. The structure of QscR bound to a synthetic agonist reveals a novel mode of ligand binding supporting a general mechanism for agonist activity. In turn, antagonists of QscR with partial agonist activity were found to destabilize and greatly impair QscR dimerization and DNA binding. These results highlight the diversity of LuxR-type receptor responses to small molecule agonists and antagonists and demonstrate the potential for chemical strategies for the selective targeting of individual QS systems.
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Affiliation(s)
- Christina L Wysoczynski-Horita
- Department of Pharmacology and Program in Structural Biology and Biochemistry, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | | | - Ryan Hill
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Kirk Hansen
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Helen E Blackwell
- Department of Chemistry, University of Wisconsin, Madison, WI 53706, USA
| | - Mair E A Churchill
- Department of Pharmacology and Program in Structural Biology and Biochemistry, University of Colorado School of Medicine, Aurora, CO 80045, USA
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93
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Flanagan ML, Arguello AE, Colman DE, Kim J, Krejci JN, Liu S, Yao Y, Zhang Y, Gorin DJ. A DNA-conjugated small molecule catalyst enzyme mimic for site-selective ester hydrolysis. Chem Sci 2018; 9:2105-2112. [PMID: 29732115 PMCID: PMC5911826 DOI: 10.1039/c7sc04554a] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Accepted: 01/10/2018] [Indexed: 12/19/2022] Open
Abstract
The challenge of site-selectivity must be overcome in many chemical research contexts, including selective functionalization in complex natural products and labeling of one biomolecule in a living system. Synthetic catalysts incorporating molecular recognition domains can mimic naturally-occurring enzymes to direct a chemical reaction to a particular instance of a functional group. We propose that DNA-conjugated small molecule catalysts (DCats), prepared by tethering a small molecule catalyst to a DNA aptamer, are a promising class of reagents for site-selective transformations. Specifically, a DNA-imidazole conjugate able to increase the rate of ester hydrolysis in a target ester by >100-fold compared with equimolar untethered imidazole was developed. Other esters are unaffected. Furthermore, DCat-catalyzed hydrolysis follows enzyme-like kinetics and a stimuli-responsive variant of the DCat enables programmable "turn on" of the desired reaction.
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Affiliation(s)
- Moira L Flanagan
- Smith College , Department of Chemistry , Northampton , MA 01063 , USA .
| | - A Emilia Arguello
- Smith College , Department of Chemistry , Northampton , MA 01063 , USA .
| | - Drew E Colman
- Smith College , Department of Chemistry , Northampton , MA 01063 , USA .
| | - Jiyeon Kim
- Smith College , Department of Chemistry , Northampton , MA 01063 , USA .
| | - Jesse N Krejci
- Smith College , Department of Chemistry , Northampton , MA 01063 , USA .
| | - Shimu Liu
- Smith College , Department of Chemistry , Northampton , MA 01063 , USA .
| | - Yueyu Yao
- Smith College , Department of Chemistry , Northampton , MA 01063 , USA .
| | - Yu Zhang
- Smith College , Department of Chemistry , Northampton , MA 01063 , USA .
| | - David J Gorin
- Smith College , Department of Chemistry , Northampton , MA 01063 , USA .
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94
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Nicol M, Alexandre S, Luizet JB, Skogman M, Jouenne T, Salcedo SP, Dé E. Unsaturated Fatty Acids Affect Quorum Sensing Communication System and Inhibit Motility and Biofilm Formation of Acinetobacter baumannii. Int J Mol Sci 2018; 19:ijms19010214. [PMID: 29320462 PMCID: PMC5796163 DOI: 10.3390/ijms19010214] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 01/07/2018] [Accepted: 01/08/2018] [Indexed: 02/07/2023] Open
Abstract
The increasing threat of Acinetobacter baumannii as a nosocomial pathogen is mainly due to the occurrence of multidrug-resistant strains that are associated with the real problem of its eradication from hospital wards. The particular ability of this pathogen to form biofilms contributes to its persistence, increases antibiotic resistance, and promotes persistent/device-related infections. We previously demonstrated that virstatin, which is a small organic compound known to decrease virulence of Vibrio cholera via an inhibition of T4-pili expression, displayed very promising activity to prevent A. baumannii biofilm development. Here, we examined the antibiofilm activity of mono-unsaturated chain fatty acids, palmitoleic (PoA), and myristoleic (MoA) acids, presenting similar action on V. cholerae virulence. We demonstrated that PoA and MoA (at 0.02 mg/mL) were able to decrease A. baumannii ATCC 17978 biofilm formation up to 38% and 24%, respectively, presented a biofilm dispersing effect and drastically reduced motility. We highlighted that these fatty acids decreased the expression of the regulator abaR from the LuxIR-type quorum sensing (QS) communication system AbaIR and consequently reduced the N-acyl-homoserine lactone production (AHL). This effect can be countered by addition of exogenous AHLs. Besides, fatty acids may have additional non-targeted effects, independent from QS. Atomic force microscopy experiments probed indeed that PoA and MoA could also act on the initial adhesion process in modifying the material interface properties. Evaluation of fatty acids effect on 22 clinical isolates showed a strain-dependent antibiofilm activity, which was not correlated to hydrophobicity or pellicle formation ability of the tested strains, and suggested a real diversity in cell-to-cell communication systems involved in A. baumannii biofilm formation.
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Affiliation(s)
- Marion Nicol
- Normandie University, Unirouen, 76000 Rouen, France.
- CNRS, UMR 6270, Polymers, Biopolymers, Surfaces Laboratory, F-76821 Mont-Saint-Aignan, France.
| | - Stéphane Alexandre
- Normandie University, Unirouen, 76000 Rouen, France.
- CNRS, UMR 6270, Polymers, Biopolymers, Surfaces Laboratory, F-76821 Mont-Saint-Aignan, France.
| | - Jean-Baptiste Luizet
- Laboratory of Molecular Microbiology and Structural Biochemistry, University of Lyon, Centre National de la Recherche Scientifique, F-69367 Lyon, France.
| | - Malena Skogman
- Department of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, Viikinkaari 5E, FI-00014 Helsinki, Finland.
| | - Thierry Jouenne
- Normandie University, Unirouen, 76000 Rouen, France.
- CNRS, UMR 6270, Polymers, Biopolymers, Surfaces Laboratory, F-76821 Mont-Saint-Aignan, France.
| | - Suzana P Salcedo
- Laboratory of Molecular Microbiology and Structural Biochemistry, University of Lyon, Centre National de la Recherche Scientifique, F-69367 Lyon, France.
| | - Emmanuelle Dé
- Normandie University, Unirouen, 76000 Rouen, France.
- CNRS, UMR 6270, Polymers, Biopolymers, Surfaces Laboratory, F-76821 Mont-Saint-Aignan, France.
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95
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Li SZ, Xu R, Ahmar M, Goux-Henry C, Queneau Y, Soulère L. Influence of the d/l configuration of N-acyl-homoserine lactones (AHLs) and analogues on their Lux-R dependent quorum sensing activity. Bioorg Chem 2018; 77:215-222. [PMID: 29367078 DOI: 10.1016/j.bioorg.2018.01.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Revised: 12/15/2017] [Accepted: 01/02/2018] [Indexed: 01/26/2023]
Abstract
Whereas l-3-oxo-hexanoyl homoserine lactone (OHHL) is the active enantiomer of the of LuxR-regulated quorum sensing (QS) autoinducer, its d isomer is implicitly considered as inactive. The present work aims to clarify this l-specificity and investigate whether it extends to some analogues in the acyl homoserine lactone (AHL) family. For this purpose, OHHL and a series of AHL analogs were synthesized in racemic and enantiomerically pure d and l forms and their ability to induce or attenuate bioluminescence in the LuxR-dependent QS system was evaluated. In this study, l-isomers are confirmed as either the only, or as the most active, enantiomers. However, in several cases, especially for the natural ligand of LuxR (OHHL) and the very similar AHL agonist analogue 2, the d-isomer cannot be considered as totally inactive on QS. Molecular modelling suggests that when the lactone moiety of the d-isomer is able to twist, enabling the lactone carbonyl group and the amide function to interact with the key residues in the binding site, then the d-isomer can exhibit some activity.
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Affiliation(s)
- Si-Zhe Li
- Univ Lyon, INSA Lyon, CNRS, Université Lyon 1, CPE Lyon, UMR 5246, ICBMS, Institut de Chimie et de Biochimie Moléculaires et Supramoléculaires, Laboratoire de Chimie Organique et Bioorganique Bât. J. Verne, 20 avenue A. Einstein, F-69621 Villeurbanne, France
| | - Rui Xu
- Univ Lyon, INSA Lyon, CNRS, Université Lyon 1, CPE Lyon, UMR 5246, ICBMS, Institut de Chimie et de Biochimie Moléculaires et Supramoléculaires, Laboratoire de Chimie Organique et Bioorganique Bât. J. Verne, 20 avenue A. Einstein, F-69621 Villeurbanne, France
| | - Mohammed Ahmar
- Univ Lyon, INSA Lyon, CNRS, Université Lyon 1, CPE Lyon, UMR 5246, ICBMS, Institut de Chimie et de Biochimie Moléculaires et Supramoléculaires, Laboratoire de Chimie Organique et Bioorganique Bât. J. Verne, 20 avenue A. Einstein, F-69621 Villeurbanne, France
| | - Catherine Goux-Henry
- Univ Lyon, Université Lyon 1, CNRS, INSA Lyon, CPE Lyon, UMR 5246, ICBMS, Institut de Chimie et de Biochimie Moléculaires et Supramoléculaires, CASYEN Bât Curien (CPE) 43, Bd du 11 Novembre 1918, 69622 Villeurbanne cedex, France
| | - Yves Queneau
- Univ Lyon, INSA Lyon, CNRS, Université Lyon 1, CPE Lyon, UMR 5246, ICBMS, Institut de Chimie et de Biochimie Moléculaires et Supramoléculaires, Laboratoire de Chimie Organique et Bioorganique Bât. J. Verne, 20 avenue A. Einstein, F-69621 Villeurbanne, France.
| | - Laurent Soulère
- Univ Lyon, INSA Lyon, CNRS, Université Lyon 1, CPE Lyon, UMR 5246, ICBMS, Institut de Chimie et de Biochimie Moléculaires et Supramoléculaires, Laboratoire de Chimie Organique et Bioorganique Bât. J. Verne, 20 avenue A. Einstein, F-69621 Villeurbanne, France.
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96
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Ó Muimhneacháin E, Reen FJ, O'Gara F, McGlacken GP. Analogues ofPseudomonas aeruginosasignalling molecules to tackle infections. Org Biomol Chem 2018; 16:169-179. [DOI: 10.1039/c7ob02395b] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The emergence of antibiotic resistance coupled with the lack of investment by pharmaceutical companies necessitates a new look at how we tackle bacterial infections.
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Affiliation(s)
- Eoin Ó Muimhneacháin
- School of Chemistry and Analytical and Biological Chemistry Research Facility
- University College Cork
- College Road
- Cork
- Ireland
| | - F. Jerry Reen
- School of Microbiology
- University College Cork
- Ireland
- BIOMERIT Research Centre
- School of Microbiology
| | - Fergal O'Gara
- BIOMERIT Research Centre
- School of Microbiology
- University College Cork
- Ireland
- School of Biomedical Sciences
| | - Gerard P. McGlacken
- School of Chemistry and Analytical and Biological Chemistry Research Facility
- University College Cork
- College Road
- Cork
- Ireland
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97
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Ma H, Wang X, Zhang Y, Hu H, Ren H, Geng J, Ding L. The diversity, distribution and function of N-acyl-homoserine lactone (AHL) in industrial anaerobic granular sludge. BIORESOURCE TECHNOLOGY 2018; 247:116-124. [PMID: 28946084 DOI: 10.1016/j.biortech.2017.09.043] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 09/05/2017] [Accepted: 09/06/2017] [Indexed: 06/07/2023]
Abstract
Although AHL-mediated quorum sensing (QS) signaling has been proved to be ecologically important in biofilm formation and aerobic granulation process, the biological role of AHL in anaerobic granule has not been experimentally investigated. In this paper, we explored the AHL level in 10 full-scale industrial anaerobic granular bioreactors and detected a total of 4 kinds of AHLs. C8-HSL and C10-HSL were indicated to be the potentially universal QS signal molecules in anaerobic granules and involved in extracellular polymeric substance (EPS) production and granulation process. The add-back experiments further supported the hypothesis that C8-HSL and C10-HSL might play an important role in facilitating anaerobic granulation through regulation of EPS synthesis. 12 Microorganisms might be regulated by AHL to play an important role in EPS production. This study provides a foundation for exploring the function of AHL in anaerobic granular systems, which may shed light on advanced AHL-based anaerobic granulation strategy.
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Affiliation(s)
- Haijun Ma
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, Jiangsu, PR China
| | - Xuezhu Wang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, Jiangsu, PR China
| | - Yan Zhang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, Jiangsu, PR China
| | - Haidong Hu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, Jiangsu, PR China
| | - Hongqiang Ren
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, Jiangsu, PR China.
| | - Jinju Geng
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, Jiangsu, PR China
| | - Lili Ding
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, Jiangsu, PR China
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98
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Abstract
Synthesizing spatial patterns with genetic networks is an ongoing challenge in synthetic biology. A successful demonstration of pattern formation would imply a better understanding of systems in the natural world and advance applications in synthetic biology. In developmental systems, transient patterning may suffice in order to imprint instructions for long-term development. In this paper we show that transient but persistent patterns can emerge from a realizable synthetic gene network based on a toggle switch. We show that a bistable system incorporating diffusible molecules can generate patterns that resemble Turing patterns but are distinctly different in the underlying mechanism: diffusion of mutually inhibiting molecules creates a prolonged "tug-of-war" between patches of cells at opposing bistable states. The patterns are transient but longer wavelength patterns persist for extended periods of time. Analysis of a representative small scale model implies the eigenvalues of the persistent modes are just above the threshold of stability. The results are verified through simulation of biologically relevant models.
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Affiliation(s)
- Marcella M. Gomez
- Electrical Engineering and Computer Sciences, UC Berkeley, Berkeley, CA, USA
| | - Murat Arcak
- Electrical Engineering and Computer Sciences, UC Berkeley, Berkeley, CA, USA
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99
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Parungao GG, Zhao M, Wang Q, Zano SP, Viola RE, Blumenthal RM. Complementation of a metK-deficient E. coli strain with heterologous AdoMet synthetase genes. MICROBIOLOGY-SGM 2017; 163:1812-1821. [PMID: 29111970 DOI: 10.1099/mic.0.000565] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
S-adenosyl-l-methionine (AdoMet) is an essential metabolite, playing a wide variety of metabolic roles. The enzyme that produces AdoMet from l-methionine and ATP (methionine adenosyltransferase, MAT) is thus an attractive target for anti-cancer and antimicrobial agents. It would be very useful to have a system that allows rapid identification of species-specific inhibitors of this essential enzyme. A previously generated E. coli strain, lacking MAT (∆metK) but containing a heterologous AdoMet transporter, was successfully complemented with heterologous metK genes from several bacterial pathogens, as well as with MAT genes from a fungal pathogen and Homo sapiens. The nine tested genes, which vary in both sequence and kinetic properties, all complemented strain MOB1490 well in rich medium. When these strains were grown in glucose minimal medium, growth delays or defects were observed with some specific metK genes, defects that were dramatically reduced if l-methionine was added to the medium.
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Affiliation(s)
- Gwenn G Parungao
- Department of Chemistry and Biochemistry, University of Toledo, Toledo, OH 43606, USA
| | - Mojun Zhao
- Department of Chemistry and Biochemistry, University of Toledo, Toledo, OH 43606, USA.,Present address: Department of Pathology, Valley Pathologists Inc., Miami Valley Hospital, Dayton, OH 45409, USA
| | - Qinzhe Wang
- Department of Chemistry and Biochemistry, University of Toledo, Toledo, OH 43606, USA
| | - Stephen P Zano
- Department of Chemistry and Biochemistry, University of Toledo, Toledo, OH 43606, USA
| | - Ronald E Viola
- Department of Chemistry and Biochemistry, University of Toledo, Toledo, OH 43606, USA
| | - Robert M Blumenthal
- Department of Medical Microbiology and Immunology and Program in Bioinformatics, University of Toledo Health Sciences Campus, Toledo, OH 43614, USA
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Xue W, Hao T, Mackey HR, Li X, Chan RC, Chen G. The role of sulfate in aerobic granular sludge process for emerging sulfate-laden wastewater treatment. WATER RESEARCH 2017; 124:513-520. [PMID: 28802136 DOI: 10.1016/j.watres.2017.08.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Revised: 08/01/2017] [Accepted: 08/03/2017] [Indexed: 06/07/2023]
Abstract
Sulfate-rich wastewaters pose a major threat to mainstream wastewater treatment due to the unpreventable production of sulfide and associated shift in functional bacteria. Aerobic granular sludge could mitigate these challenges in view of its high tolerance and resilience against changes in various environmental conditions. This study aims to confirm the feasibility of aerobic granular sludge in the treatment of sulfate containing wastewater, investigate the impact of sulfate on nutrient removal and granulation, and reveal metabolic relationships in the above processes. Experiments were conducted using five sequencing batch reactors with different sulfate concentrations operated under alternating anoxic/aerobic condition. Results showed that effect of sulfate on chemical oxygen demand (COD) removal is negligible, while phosphate removal was enhanced from 12% to 87% with an increase in sulfate from 0 to 200 mg/L. However, a long acclimatization of the biomass (more than 70 days) is needed at a sulfate concentration of 500 mg/L and a total deterioration of phosphate removal at 1000 mg/L. Batch tests revealed that sulfide promoted volatile fatty acids (VFAs) uptake, producing more energy for phosphate uptake when sulfate concentrations were beneath 200 mg/L. However, sulfide detoxification became energy dominating, leaving insufficient energy for Polyhydroxyalkanoate (PHA) synthesis and phosphate uptake when sulfate content was further increased. Granulation accelerated with increasing sulfate levels by enhanced production of N-Acyl homoserine lactones (AHLs), a kind of quorum sensing (QS) auto-inducer, using S-Adenosyl Methionine (SAM) as primer. The current study demonstrates interactions among sulfate metabolism, nutrients removal and granulation, and confirms the feasibility of using the aerobic granular sludge process for sulfate-laden wastewaters treatment with low to medium sulfate content.
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Affiliation(s)
- Weiqi Xue
- Department of Civil & Environmental Engineering, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Tianwei Hao
- Department of Civil & Environmental Engineering, The Hong Kong University of Science and Technology, Hong Kong, China; Institute for Advanced Study, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong.
| | - Hamish R Mackey
- Division of Sustainable Development, College of Science and Engineering, Hamad Bin Khalifa University, Qatar Foundation, Doha, Qatar
| | - Xiling Li
- Department of Civil & Environmental Engineering, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Richard C Chan
- Department of Civil & Environmental Engineering, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Guanghao Chen
- Department of Civil & Environmental Engineering, The Hong Kong University of Science and Technology, Hong Kong, China; Water Technology Center, The Hong Kong University of Science and Technology, Hong Kong, China; Hong Kong Branch of Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, The Hong Kong University of Science and Technology, Hong Kong, China; Wastewater Treatment Laboratory, FYT Graduate School, The Hong Kong University of Science and Technology, Nansha, Guangzhou, China
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