301
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Prajapati NP, Vekariya RH, Patel HD. Ceric Ammonium Nitrate (CAN)–Catalyzed Multicomponent Reactions: An Efficient Catalyst for Green Organic Synthesis. SYNTHETIC COMMUN 2015. [DOI: 10.1080/00397911.2015.1045986] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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302
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Phelan VV, Fang J, Dorrestein PC. Mass Spectrometry Analysis of Pseudomonas aeruginosa Treated with Azithromycin. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2015; 26:873-877. [PMID: 25801585 PMCID: PMC4425625 DOI: 10.1007/s13361-015-1101-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Revised: 02/09/2015] [Accepted: 02/09/2015] [Indexed: 06/04/2023]
Abstract
In microbiology, changes in specialized metabolite production (cell-to-cell signaling metabolites, virulence factors, and natural products) are measured using phenotypic assays. However, advances in mass spectrometry-based techniques including imaging mass spectrometry (IMS) now allow researchers to directly visualize the production of specialized metabolites from microbial colony biofilms. In this study, a combination of IMS and liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to visualize the effect of the macrolide antibiotic azithromycin (AZM) on colony biofilms of Pseudomonas aeruginosa. Although previous research suggested that AZM may inhibit cell-to-cell signaling of P. aeruginosa and thereby reduce pathogenicity, we observed no clear decrease in specialized metabolite production.
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Affiliation(s)
- Vanessa V Phelan
- Collaborative Mass Spectrometry Innovation Center, Skaggs School of Pharmacy and Pharmaceutical Sciences University of California, San Diego, La Jolla, CA, 92093, USA,
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303
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Husain FM, Ahmad I, Khan MS, Ahmad E, Tahseen Q, Khan MS, Alshabib NA. Sub-MICs of Mentha piperita essential oil and menthol inhibits AHL mediated quorum sensing and biofilm of Gram-negative bacteria. Front Microbiol 2015; 6:420. [PMID: 26029178 PMCID: PMC4429619 DOI: 10.3389/fmicb.2015.00420] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Accepted: 04/21/2015] [Indexed: 01/17/2023] Open
Abstract
Bacterial quorum sensing (QS) is a density dependent communication system that regulates the expression of certain genes including production of virulence factors in many pathogens. Bioactive plant extract/compounds inhibiting QS regulated gene expression may be a potential candidate as antipathogenic drug. In this study anti-QS activity of peppermint (Mentha piperita) oil was first tested using the Chromobacterium violaceum CVO26 biosensor. Further, the findings of the present investigation revealed that peppermint oil (PMO) at sub-Minimum Inhibitory Concentrations (sub-MICs) strongly interfered with acyl homoserine lactone (AHL) regulated virulence factors and biofilm formation in Pseudomonas aeruginosa and Aeromonas hydrophila. The result of molecular docking analysis attributed the QS inhibitory activity exhibited by PMO to menthol. Assessment of ability of menthol to interfere with QS systems of various Gram-negative pathogens comprising diverse AHL molecules revealed that it reduced the AHL dependent production of violacein, virulence factors, and biofilm formation indicating broad-spectrum anti-QS activity. Using two Escherichia coli biosensors, MG4/pKDT17 and pEAL08-2, we also confirmed that menthol inhibited both the las and pqs QS systems. Further, findings of the in vivo studies with menthol on nematode model Caenorhabditis elegans showed significantly enhanced survival of the nematode. Our data identified menthol as a novel broad spectrum QS inhibitor.
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Affiliation(s)
- Fohad M Husain
- Department of Agricultural Microbiology, Aligarh Muslim University Aligarh, India ; Department of Food Science and Nutrition, College of Food and Agricultural Sciences, King Saud University Riyadh, Saudi Arabia
| | - Iqbal Ahmad
- Department of Agricultural Microbiology, Aligarh Muslim University Aligarh, India
| | - Mohammad S Khan
- Department of Agricultural Microbiology, Aligarh Muslim University Aligarh, India
| | - Ejaz Ahmad
- School of Pharmaceutical Sciences, Sao Paulo State University Araraquara, Brazil
| | - Qudisa Tahseen
- Department of Zoology, Aligarh Muslim University Aligarh, India
| | - Mohd Shahnawaz Khan
- Department of Biochemistry, Protein Research Chair, College of Science, King Saud University Riyadh, Saudi Arabia
| | - Nasser A Alshabib
- Department of Food Science and Nutrition, College of Food and Agricultural Sciences, King Saud University Riyadh, Saudi Arabia
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304
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Drees SL, Fetzner S. PqsE of Pseudomonas aeruginosa Acts as Pathway-Specific Thioesterase in the Biosynthesis of Alkylquinolone Signaling Molecules. ACTA ACUST UNITED AC 2015; 22:611-8. [PMID: 25960261 DOI: 10.1016/j.chembiol.2015.04.012] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Revised: 04/02/2015] [Accepted: 04/07/2015] [Indexed: 01/18/2023]
Abstract
Pseudomonas aeruginosa uses the alkylquinolones PQS (2-heptyl-3-hydroxy-4(1H)-quinolone) and HHQ (2-heptyl-4(1H)-quinolone) as quorum-sensing signal molecules, controlling the expression of many virulence genes as a function of cell population density. The biosynthesis of HHQ is generally accepted to require the pqsABCD gene products. We now reconstitute the biosynthetic pathway in vitro, and demonstrate that in addition to PqsABCD, PqsE has a role in HHQ synthesis. PqsE acts as thioesterase, hydrolyzing the biosynthetic intermediate 2-aminobenzoylacetyl-coenzyme A to form 2-aminobenzoylacetate, the precursor of HHQ and 2-aminoacetophenone. The role of PqsE can be taken over to some extent by the broad-specificity thioesterase TesB, explaining why the pqsE deletion mutant of P. aeruginosa still synthesizes HHQ. Interestingly, the pqsE mutant produces increased levels of 2,4-dihydroxyquinoline, resulting from intramolecular cyclization of 2-aminobenzoylacetyl-coenzyme A. Overall, our data suggest that PqsE promotes the efficiency of alkylquinolone signal molecule biosynthesis in P. aeruginosa and balances the levels of secondary metabolites deriving from the alkylquinolone biosynthetic pathway.
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Affiliation(s)
- Steffen Lorenz Drees
- Institute of Molecular Microbiology and Biotechnology, University of Münster, Corrensstrasse 3, 48149 Münster, Germany
| | - Susanne Fetzner
- Institute of Molecular Microbiology and Biotechnology, University of Münster, Corrensstrasse 3, 48149 Münster, Germany.
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305
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Sams T, Baker Y, Hodgkinson J, Gross J, Spring D, Welch M. The Pseudomonas Quinolone Signal (PQS). Isr J Chem 2015. [DOI: 10.1002/ijch.201400128] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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306
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Metal-free intramolecular transannulation of N,3-diaryloxirane-2-carboxamides: a concise and versatile route to 3-arylquinolin-2(1H)-ones. Tetrahedron 2015. [DOI: 10.1016/j.tet.2015.03.038] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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307
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Soh EYC, Chhabra SR, Halliday N, Heeb S, Müller C, Birmes FS, Fetzner S, Cámara M, Chan KG, Williams P. Biotic inactivation of the Pseudomonas aeruginosa quinolone signal molecule. Environ Microbiol 2015; 17:4352-65. [PMID: 25809238 DOI: 10.1111/1462-2920.12857] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Revised: 03/06/2015] [Accepted: 03/06/2015] [Indexed: 11/29/2022]
Abstract
In Pseudomonas aeruginosa, quorum sensing (QS) regulates the production of secondary metabolites, many of which are antimicrobials that impact on polymicrobial community composition. Consequently, quenching QS modulates the environmental impact of P. aeruginosa. To identify bacteria capable of inactivating the QS signal molecule 2-heptyl-3-hydroxy-4(1H)-quinolone (PQS), a minimal medium containing PQS as the sole carbon source was used to enrich a Malaysian rainforest soil sample. This yielded an Achromobacter xylosoxidans strain (Q19) that inactivated PQS, yielding a new fluorescent compound (I-PQS) confirmed as PQS-derived using deuterated PQS. The I-PQS structure was elucidated using mass spectrometry and nuclear magnetic resonance spectroscopy as 2-heptyl-2-hydroxy-1,2-dihydroquinoline-3,4-dione (HHQD). Achromobacter xylosoxidans Q19 oxidized PQS congeners with alkyl chains ranging from C1 to C5 and also N-methyl PQS, yielding the corresponding 2-hydroxy-1,2-dihydroquinoline-3,4-diones, but was unable to inactivate the PQS precursor HHQ. This indicates that the hydroxyl group at position 3 in PQS is essential and that A. xylosoxidans inactivates PQS via a pathway involving the incorporation of oxygen at C2 of the heterocyclic ring. The conversion of PQS to HHQD also occurred on incubation with 12/17 A. xylosoxidans strains recovered from cystic fibrosis patients, with P. aeruginosa and with Arthrobacter, suggesting that formation of hydroxylated PQS may be a common mechanism of inactivation.
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Affiliation(s)
- Eliza Ye-Chen Soh
- Centre for Biomolecular Sciences, School of Life Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD, UK.,Division of Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, 50603, Malaysia
| | - Siri R Chhabra
- Centre for Biomolecular Sciences, School of Life Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - Nigel Halliday
- Centre for Biomolecular Sciences, School of Life Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - Stephan Heeb
- Centre for Biomolecular Sciences, School of Life Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - Christine Müller
- Institute of Molecular Microbiology and Biotechnology, University of Muenster, D-48149, Muenster, Germany
| | - Franziska S Birmes
- Institute of Molecular Microbiology and Biotechnology, University of Muenster, D-48149, Muenster, Germany
| | - Susanne Fetzner
- Institute of Molecular Microbiology and Biotechnology, University of Muenster, D-48149, Muenster, Germany
| | - Miguel Cámara
- Centre for Biomolecular Sciences, School of Life Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - Kok-Gan Chan
- Division of Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, 50603, Malaysia
| | - Paul Williams
- Centre for Biomolecular Sciences, School of Life Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
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308
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Iron Depletion Enhances Production of Antimicrobials by Pseudomonas aeruginosa. J Bacteriol 2015; 197:2265-75. [PMID: 25917911 DOI: 10.1128/jb.00072-15] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Accepted: 04/23/2015] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Cystic fibrosis (CF) is a heritable disease characterized by chronic, polymicrobial lung infections. While Staphylococcus aureus is the dominant lung pathogen in young CF patients, Pseudomonas aeruginosa becomes predominant by adulthood. P. aeruginosa produces a variety of antimicrobials that likely contribute to this shift in microbial populations. In particular, secretion of 2-alkyl-4(1H)-quinolones (AQs) contributes to lysis of S. aureus in coculture, providing an iron source to P. aeruginosa both in vitro and in vivo. We previously showed that production of one such AQ, the Pseudomonas quinolone signal (PQS), is enhanced by iron depletion and that this induction is dependent upon the iron-responsive PrrF small RNAs (sRNAs). Here, we demonstrate that antimicrobial activity against S. aureus during coculture is also enhanced by iron depletion, and we provide evidence that multiple AQs contribute to this activity. Strikingly, a P. aeruginosa ΔprrF mutant, which produces very little PQS in monoculture, was capable of mediating iron-regulated growth suppression of S. aureus. We show that the presence of S. aureus suppresses the ΔprrF1,2 mutant's defect in iron-regulated PQS production, indicating that a PrrF-independent iron regulatory pathway mediates AQ production in coculture. We further demonstrate that iron-regulated antimicrobial production is conserved in multiple P. aeruginosa strains, including clinical isolates from CF patients. These results demonstrate that iron plays a central role in modulating interactions of P. aeruginosa with S. aureus. Moreover, our studies suggest that established iron regulatory pathways of these pathogens are significantly altered during polymicrobial infections. IMPORTANCE Chronic polymicrobial infections involving Pseudomonas aeruginosa and Staphylococcus aureus are a significant cause of morbidity and mortality, as the interplay between these two organisms exacerbates infection. This is in part due to enhanced production of antimicrobial metabolites by P. aeruginosa when these two species are cocultured. Using both established and newly developed coculture techniques, this report demonstrates that iron depletion increases P. aeruginosa's ability to suppress growth of S. aureus. These findings present a novel role for iron in modulating microbial interaction and provide the basis for understanding how essential nutrients drive polymicrobial infections.
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309
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CysB Negatively Affects the Transcription of pqsR and Pseudomonas Quinolone Signal Production in Pseudomonas aeruginosa. J Bacteriol 2015; 197:1988-2002. [PMID: 25845844 DOI: 10.1128/jb.00246-15] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 03/27/2015] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Pseudomonas aeruginosa is a Gram-negative bacterium that is ubiquitous in the environment, and it is an opportunistic pathogen that can infect a variety of hosts, including humans. During the process of infection, P. aeruginosa coordinates the expression of numerous virulence factors through the production of multiple cell-to-cell signaling molecules. The production of these signaling molecules is linked through a regulatory network, with the signal N-(3-oxododecanoyl) homoserine lactone and its receptor LasR controlling the induction of a second acyl-homoserine lactone signal and the Pseudomonas quinolone signal (PQS). LasR-mediated control of PQS occurs partly by activating the transcription of pqsR, a gene that encodes the PQS receptor and is necessary for PQS production. We show that LasR interacts with a single binding site in the pqsR promoter region and that it does not influence the transcription of the divergently transcribed gene, nadA. Using DNA affinity chromatography, we identified additional proteins that interact with the pqsR-nadA intergenic region. These include the H-NS family members MvaT and MvaU, and CysB, a transcriptional regulator that controls sulfur uptake and cysteine biosynthesis. We show that CysB interacts with the pqsR promoter and that CysB represses pqsR transcription and PQS production. Additionally, we provide evidence that CysB can interfere with the activation of pqsR transcription by LasR. However, as seen with other CysB-regulated genes, pqsR expression was not differentially regulated in response to cysteine levels. These findings demonstrate a novel role for CysB in influencing cell-to-cell signal production by P. aeruginosa. IMPORTANCE The production of PQS and other 4-hydroxy-2-alkylquinolone (HAQs) compounds is a key component of the P. aeruginosa cell-to-cell signaling network, impacts multiple physiological functions, and is required for virulence. PqsR directly regulates the genes necessary for HAQ production, but little is known about the regulation of pqsR. We identified CysB as a novel regulator of pqsR and PQS production, but, unlike other CysB-controlled genes, it does not appear to regulate pqsR in response to cysteine. This implies that CysB functions as both a cysteine-responsive and cysteine-unresponsive regulator in P. aeruginosa.
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310
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Perron GG, Whyte L, Turnbaugh PJ, Goordial J, Hanage WP, Dantas G, Desai MM. Functional characterization of bacteria isolated from ancient arctic soil exposes diverse resistance mechanisms to modern antibiotics. PLoS One 2015; 10:e0069533. [PMID: 25807523 PMCID: PMC4373940 DOI: 10.1371/journal.pone.0069533] [Citation(s) in RCA: 124] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Accepted: 01/14/2015] [Indexed: 12/03/2022] Open
Abstract
Using functional metagenomics to study the resistomes of bacterial communities isolated from different layers of the Canadian high Arctic permafrost, we show that microbial communities harbored diverse resistance mechanisms at least 5,000 years ago. Among bacteria sampled from the ancient layers of a permafrost core, we isolated eight genes conferring clinical levels of resistance against aminoglycoside, β-lactam and tetracycline antibiotics that are naturally produced by microorganisms. Among these resistance genes, four also conferred resistance against amikacin, a modern semi-synthetic antibiotic that does not naturally occur in microorganisms. In bacteria sampled from the overlaying active layer, we isolated ten different genes conferring resistance to all six antibiotics tested in this study, including aminoglycoside, β-lactam and tetracycline variants that are naturally produced by microorganisms as well as semi-synthetic variants produced in the laboratory. On average, we found that resistance genes found in permafrost bacteria conferred lower levels of resistance against clinically relevant antibiotics than resistance genes sampled from the active layer. Our results demonstrate that antibiotic resistance genes were functionally diverse prior to the anthropogenic use of antibiotics, contributing to the evolution of natural reservoirs of resistance genes.
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Affiliation(s)
- Gabriel G. Perron
- FAS Center for Systems Biology, Harvard University, 52 Oxford Street, Cambridge, Massachusetts, 02138, United States of America
- Department of Evolutionary and Organismic Biology, Harvard University, 52 Oxford Street, Cambridge, Massachusetts, 02138, United States of America
- Biology Program, Bard College, 30 Campus Road, Annandale-on-Hudson, New York, 12504, United States of America
| | - Lyle Whyte
- Department of Natural Resource Sciences, McGill University, Macdonald Campus, 21,111 Lakeshore, Ste-Anne-de-Bellevue, Quebec, H9X 3V9, Canada
| | - Peter J. Turnbaugh
- FAS Center for Systems Biology, Harvard University, 52 Oxford Street, Cambridge, Massachusetts, 02138, United States of America
- Department of Microbiology and Immunology, Hooper Foundation, University of California San Francisco, 513 Parnassus Ave, San Francisco, California, 94143, United States of America
| | - Jacqueline Goordial
- Department of Natural Resource Sciences, McGill University, Macdonald Campus, 21,111 Lakeshore, Ste-Anne-de-Bellevue, Quebec, H9X 3V9, Canada
| | - William P. Hanage
- Department of Epidemiology, Harvard School of Public School, 677 Huntington Avenue, Boston, Massachusetts, 02115, United States of America
| | - Gautam Dantas
- Center for Genome Sciences and Systems Biology, Washington University School of Medicine, 4444 Forest Park Avenue, St. Louis, Missouri, 63108, United States of America
- Department of Pathology and Immunology, Washington University School of Medicine, 4444 Park Forest Avenue, St. Louis, Missouri, 63108, United States of America
| | - Michael M. Desai
- FAS Center for Systems Biology, Harvard University, 52 Oxford Street, Cambridge, Massachusetts, 02138, United States of America
- Department of Evolutionary and Organismic Biology, Harvard University, 52 Oxford Street, Cambridge, Massachusetts, 02138, United States of America
- Department of Physics, Harvard University, Cambridge, Massachusetts, 02138, United States of America
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311
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Spoils of war: iron at the crux of clinical and ecological fitness of Pseudomonas aeruginosa. Biometals 2015; 28:433-43. [DOI: 10.1007/s10534-015-9848-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Accepted: 03/13/2015] [Indexed: 01/07/2023]
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312
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Kim HS, Lee SH, Byun Y, Park HD. 6-Gingerol reduces Pseudomonas aeruginosa biofilm formation and virulence via quorum sensing inhibition. Sci Rep 2015; 5:8656. [PMID: 25728862 PMCID: PMC4345325 DOI: 10.1038/srep08656] [Citation(s) in RCA: 171] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Accepted: 01/29/2015] [Indexed: 02/01/2023] Open
Abstract
Pseudomonas aeruginosa is a well-known pathogenic bacterium that forms biofilms and produces virulence factors via quorum sensing (QS). Interfering with normal QS interactions between signal molecules and their cognate receptors is a developing strategy for attenuating its virulence. Here we tested the hypothesis that 6-gingerol, a pungent oil of fresh ginger, reduces biofilm formation and virulence by antagonistically binding to P. aeruginosa QS receptors. In silico studies demonstrated molecular binding occurs between 6-gingerol and the QS receptor LasR through hydrogen bonding and hydrophobic interactions. Experimentally 6-gingerol reduced biofilm formation, several virulence factors (e.g., exoprotease, rhamnolipid, and pyocyanin), and mice mortality. Further transcriptome analyses demonstrated that 6-gingerol successfully repressed QS-induced genes, specifically those related to the production of virulence factors. These results strongly support our hypothesis and offer insight into the molecular mechanism that caused QS gene repression.
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Affiliation(s)
- Han-Shin Kim
- School of Civil, Environmental and Architectural Engineering, Korea University, Anam-Dong, Seongbuk-Gu, Seoul 136-713, South Korea
| | - Sang-Hoon Lee
- School of Civil, Environmental and Architectural Engineering, Korea University, Anam-Dong, Seongbuk-Gu, Seoul 136-713, South Korea
| | - Youngjoo Byun
- College of Pharmacy, Korea University, Sejong-ro 2511, Jochiwon-eup, Sejong, 339-700, South Korea
| | - Hee-Deung Park
- School of Civil, Environmental and Architectural Engineering, Korea University, Anam-Dong, Seongbuk-Gu, Seoul 136-713, South Korea
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313
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Hochfellner C, Evangelopoulos D, Zloh M, Wube A, Guzman JD, McHugh TD, Kunert O, Bhakta S, Bucar F. Antagonistic effects of indoloquinazoline alkaloids on antimycobacterial activity of evocarpine. J Appl Microbiol 2015; 118:864-72. [PMID: 25604161 DOI: 10.1111/jam.12753] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Revised: 12/17/2014] [Accepted: 01/09/2015] [Indexed: 11/27/2022]
Abstract
AIMS The interaction of quinolone and indoloquinazoline alkaloids concerning their antimycobacterial activity was studied. METHODS AND RESULTS The antimycobacterial and modulating activity of evodiamine (1), rutaecarpine (2) and evocarpine (3) was tested on mycobacteria including three multidrug-resistant (MDR) clinical isolates of Mycobacterium tuberculosis. Antagonistic effects were concluded from fractional inhibitory concentration (FICI) values. Interaction energies of the compounds were calculated using GLUE docking module implemented in GRID. 1 and 2 exhibited weak inhibition of rapidly growing mycobacteria, however, 1 was active against Myco. tuberculosis H37Rv (MIC = 10 mg l(-1) ) while 2 was inactive. Both 1 and 2 showed a marked antagonistic effect on the susceptibility of different mycobacterial strains to 3 giving FICI values between 5 and 9. The interaction energies between compounds 1 and 2 with compound 3 suggested the possibility of complex formation in solution. CONCLUSIONS Indoloquinazoline alkaloids markedly reduce the antimycobacterial effect of the quinolone alkaloid evocarpine. Complex formation may play a role in the attenuation of its antimycobacterial activity. SIGNIFICANCE AND IMPACT OF THE STUDY This study gives a striking example of antagonism between compounds present in the same plant extract which should be considered in natural product based screening projects.
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Affiliation(s)
- C Hochfellner
- Institute of Pharmaceutical Sciences, Department of Pharmacognosy, University of Graz, Graz, Austria
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314
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Aksenov AV, Smirnov AN, Aksenov NA, Aksenova IV, Matheny JP, Rubin M. Metal-free ring expansion of indoles with nitroalkenes: a simple, modular approach to 3-substituted 2-quinolones. RSC Adv 2015. [DOI: 10.1039/c4ra14406f] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
3-Substituted 2-quinolones are obtained via a novel metal-free transannulation reaction of 2-nitroolefins with 2-substituted indoles in polyphosphoric acid.
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Affiliation(s)
- Alexander V. Aksenov
- Department of Chemistry
- North Caucasus Federal University
- Stavropol 355009
- Russian Federation
| | - Alexander N. Smirnov
- Department of Chemistry
- North Caucasus Federal University
- Stavropol 355009
- Russian Federation
| | - Nicolai A. Aksenov
- Department of Chemistry
- North Caucasus Federal University
- Stavropol 355009
- Russian Federation
| | - Inna V. Aksenova
- Department of Chemistry
- North Caucasus Federal University
- Stavropol 355009
- Russian Federation
| | | | - Michael Rubin
- Department of Chemistry
- North Caucasus Federal University
- Stavropol 355009
- Russian Federation
- Department of Chemistry
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315
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Jiménez-Sánchez A, Yatsimirsky AK. Acid–base and coordination properties of 2-phenyl-3-hydroxy-4-quinolones in aqueous media. RSC Adv 2015. [DOI: 10.1039/c5ra10217k] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
2-Phenyl-3-hydroxy-4-quinolones bind metal ions with selective fluorescence response in aqueous media.
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316
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Minovski N, Novic M, Solmajer T. The impact of Mycobacterium tuberculosis gyrB point mutations on 6-fluoroquinolones resistance profile: in silico mutagenesis and structure-based assessment. RSC Adv 2015. [DOI: 10.1039/c4ra16031b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The latest confirmedM. tuberculosis gyrBpoint mutations assembling thegyrBhot spot region strongly involved in 6-fluoroquinolones resistance for the first time enabled thein silicoconstruction and structure-based assays ongyrBmutant models.
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Affiliation(s)
- Nikola Minovski
- Laboratory for Chemometrics
- National Institute of Chemistry
- 1001 Ljubljana
- Slovenia
| | - Marjana Novic
- Laboratory for Chemometrics
- National Institute of Chemistry
- 1001 Ljubljana
- Slovenia
| | - Tom Solmajer
- Laboratory for Molecular Modeling
- National Institute of Chemistry
- 1001 Ljubljana
- Slovenia
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317
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Pezzoni M, Meichtry M, Pizarro RA, Costa CS. Role of the Pseudomonas quinolone signal (PQS) in sensitising Pseudomonas aeruginosa to UVA radiation. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2015; 142:129-40. [DOI: 10.1016/j.jphotobiol.2014.11.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Revised: 11/20/2014] [Accepted: 11/24/2014] [Indexed: 10/24/2022]
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318
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Vadekeetil A, Kaur G, Chhibber S, Harjai K. Applications of thin-layer chromatography in extraction and characterisation of ajoene from garlic bulbs. Nat Prod Res 2014; 29:768-71. [PMID: 25423012 DOI: 10.1080/14786419.2014.981815] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Novel and inexpensive methods of thin-layer chromatography (TLC) were employed for the extraction, characterisation and mechanism of quorum sensing inhibition by ajoene, a component from toluene garlic bulb (Allium sativum L.) extract (TGE). TLC profiling of TGE was carried out using ethyl acetate as solvent. Out of total spots extracted from TLC, four spots exhibited quorum sensing inhibitory (QSI) potential. Among those, spot 5 was identified as Z-ajoene by TLC and confirmed by NMR and MS. HPLC analysis indicated 97.7% purity for purified ajoene. TLC densitometric analysis quantified 221.08 μmol/g of ajoene in TGE and indicated that ajoene is stable at 4°C and at acidic pH. HPTLC profiling showed that ajoene exhibits QSI effect by inhibiting the production of both long-chain acyl homoserine lactones and Pseudomonas quinolone signal (PQS) by P. aeruginosa and also by inactivating PQS molecules.
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Affiliation(s)
- Anitha Vadekeetil
- a Department of Microbiology , Panjab University , Chandigarh 160014 , India
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319
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Yu YY, Ranade AR, Georg GI. Transition Metal-Free Direct Trifluoromethylation of 2,3-Dihydropyridin-4(1H)-ones at Room Temperature. Adv Synth Catal 2014. [DOI: 10.1002/adsc.201400417] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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320
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Aksenov AV, Smirnov AN, Aksenov NA, Aksenova IV, Bijieva AS, Rubin M. Highly efficient modular metal-free synthesis of 3-substituted 2-quinolones. Org Biomol Chem 2014; 12:9786-8. [DOI: 10.1039/c4ob02131b] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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321
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Inhibition of hepatitis C virus replication by chalepin and pseudane IX isolated from Ruta angustifolia leaves. Fitoterapia 2014; 99:276-83. [PMID: 25454460 DOI: 10.1016/j.fitote.2014.10.011] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Revised: 10/11/2014] [Accepted: 10/14/2014] [Indexed: 02/08/2023]
Abstract
Hepatitis C virus (HCV) infection is highly prevalent among global populations, with an estimated number of infected patients being 170 million. Approximately 70-80% of patients acutely infected with HCV will progress to chronic liver disease, such as liver cirrhosis and hepatocellular carcinoma, which is a substantial cause of morbidity and mortality worldwide. New therapies for HCV infection have been developed, however, the therapeutic efficacies still need to be improved. Medicinal plants are promising sources for antivirals against HCV. A variety of plants have been tested and proven to be beneficial as antiviral drug candidates against HCV. In this study, we examined extracts, their subfractions and isolated compounds of Ruta angustifolia leaves for antiviral activities against HCV in cell culture. We isolated six compounds, chalepin, scopoletin, γ-fagarine, arborinine, kokusaginine and pseudane IX. Among them, chalepin and pseudane IX showed strong anti-HCV activities with 50% inhibitory concentration (IC₅₀) of 1.7 ± 0.5 and 1.4 ± 0.2 μg/ml, respectively, without apparent cytotoxicity. Their anti-HCV activities were stronger than that of ribavirin (2.8 ± 0.4 μg/ml), which has been widely used for the treatment of HCV infection. Mode-of-action analyses revealed that chalepin and pseudane IX inhibited HCV at the post-entry step and decreased the levels of HCV RNA replication and viral protein synthesis. We also observed that arborinine, kokusaginine and γ-fagarine possessed moderate levels of anti-HCV activities with IC₅₀ values being 6.4 ± 0.7, 6.4 ± 1.6 and 20.4 ± 0.4 μg/ml, respectively, whereas scopoletin did not exert significant anti-HCV activities at 30 μg/ml.
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322
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Nolan MT, Bray JT, Eccles K, Cheung MS, Lin Z, Lawrence SE, Whitwood AC, Fairlamb IJ, McGlacken GP. Pd-catalysed intramolecular regioselective arylation of 2-pyrones, pyridones, coumarins and quinolones by C–H bond functionalization. Tetrahedron 2014. [DOI: 10.1016/j.tet.2014.04.029] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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323
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Conversion of the Pseudomonas aeruginosa Quinolone Signal and Related Alkylhydroxyquinolines by Rhodococcus sp. Strain BG43. Appl Environ Microbiol 2014; 80:7266-74. [PMID: 25239889 DOI: 10.1128/aem.02342-14] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Accepted: 09/11/2014] [Indexed: 11/20/2022] Open
Abstract
A bacterial strain, which based on the sequences of its 16S rRNA, gyrB, catA, and qsdA genes, was identified as a Rhodococcus sp. closely related to Rhodococcus erythropolis, was isolated from soil by enrichment on the Pseudomonas quinolone signal [PQS; 2-heptyl-3-hydroxy-4(1H)-quinolone], a quorum sensing signal employed by the opportunistic pathogen Pseudomonas aeruginosa. The isolate, termed Rhodococcus sp. strain BG43, cometabolically degraded PQS and its biosynthetic precursor 2-heptyl-4(1H)-quinolone (HHQ) to anthranilic acid. HHQ degradation was accompanied by transient formation of PQS, and HHQ hydroxylation by cell extracts required NADH, indicating that strain BG43 has a HHQ monooxygenase isofunctional to the biosynthetic enzyme PqsH of P. aeruginosa. The enzymes catalyzing HHQ hydroxylation and PQS degradation were inducible by PQS, suggesting a specific pathway. Remarkably, Rhodococcus sp. BG43 is also capable of transforming 2-heptyl-4-hydroxyquinoline-N-oxide to PQS. It thus converts an antibacterial secondary metabolite of P. aeruginosa to a quorum sensing signal molecule.
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324
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Fetzner S. Quorum quenching enzymes. J Biotechnol 2014; 201:2-14. [PMID: 25220028 DOI: 10.1016/j.jbiotec.2014.09.001] [Citation(s) in RCA: 192] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Revised: 08/29/2014] [Accepted: 09/04/2014] [Indexed: 01/12/2023]
Abstract
Bacteria use cell-to-cell communication systems based on chemical signal molecules to coordinate their behavior within the population. These quorum sensing systems are potential targets for antivirulence therapies, because many bacterial pathogens control the expression of virulence factors via quorum sensing networks. Since biofilm maturation is also usually influenced by quorum sensing, quenching these systems may contribute to combat biofouling. One possibility to interfere with quorum sensing is signal inactivation by enzymatic degradation or modification. Such quorum quenching enzymes are wide-spread in the bacterial world and have also been found in eukaryotes. Lactonases and acylases that hydrolyze N-acyl homoserine lactone (AHL) signaling molecules have been investigated most intensively, however, different oxidoreductases active toward AHLs or 2-alkyl-4(1H)-quinolone signals as well as other signal-converting enzymes have been described. Several approaches have been assessed which aim at alleviating virulence, or biofilm formation, by reducing the signal concentration in the bacterial environment. These involve the application or stimulation of signal-degrading bacteria as biocontrol agents in the protection of crop plants against soft-rot disease, the use of signal-degrading bacteria as probiotics in aquaculture, and the immobilization or entrapment of quorum quenching enzymes or bacteria to control biofouling in membrane bioreactors. While most approaches to use quorum quenching as antivirulence strategy are still in the research phase, the growing number of organisms and enzymes known to interfere with quorum sensing opens up new perspectives for the development of innovative antibacterial strategies.
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Affiliation(s)
- Susanne Fetzner
- Institute of Molecular Microbiology and Biotechnology, University of Muenster, Corrensstrasse 3, D-48149 Muenster, Germany.
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325
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Reznikov LR, Abou Alaiwa MH, Dohrn CL, Gansemer ND, Diekema DJ, Stoltz DA, Welsh MJ. Antibacterial properties of the CFTR potentiator ivacaftor. J Cyst Fibros 2014; 13:515-9. [PMID: 24618508 PMCID: PMC4718582 DOI: 10.1016/j.jcf.2014.02.004] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Revised: 01/29/2014] [Accepted: 02/06/2014] [Indexed: 11/22/2022]
Abstract
BACKGROUND Ivacaftor increases CFTR channel activity and improves pulmonary function for individuals bearing a G551D mutation. Because ivacaftor structurally resembles quinolone antibiotics, we tested the hypothesis that ivacaftor possesses antibacterial properties. METHODS Bioluminescence, colony forming unit, and minimal inhibitory concentration assays were used to assess viability of Staphylococcus aureus, Pseudomonas aeruginosa and multiple clinical microbial isolates. RESULTS Ivacaftor induced a dose-dependent reduction in bioluminescence of S. aureus and decreased the number of colony forming units. We observed a similar but less robust effect in P. aeruginosa following outer membrane permeabilization. Ivacaftor inhibited the growth of respiratory isolates of S. aureus and Streptococcus pneumoniae and exhibited positive interactions with antibiotics against lab and respiratory strains of S. aureus and S. pneumoniae. CONCLUSION These data indicate that ivacaftor exhibits antibacterial properties and raise the intriguing possibility that ivacaftor might have an antibiotic effect in people with CF.
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Affiliation(s)
- Leah R Reznikov
- Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, IA 52333, United States
| | - Mahmoud H Abou Alaiwa
- Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, IA 52333, United States
| | - Cassie L Dohrn
- Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, IA 52333, United States
| | - Nick D Gansemer
- Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, IA 52333, United States
| | - Daniel J Diekema
- Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, IA 52333, United States
| | - David A Stoltz
- Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, IA 52333, United States
| | - Michael J Welsh
- Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, IA 52333, United States; Howard Hughes Medical Institute (HHMI), University of Iowa Carver College of Medicine, Iowa City, IA 52333, United States; Department of Molecular Physiology and Biophysics, University of Iowa Carver College of Medicine, Iowa City, IA 52333, United States.
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326
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Starkey M, Lepine F, Maura D, Bandyopadhaya A, Lesic B, He J, Kitao T, Righi V, Milot S, Tzika A, Rahme L. Identification of anti-virulence compounds that disrupt quorum-sensing regulated acute and persistent pathogenicity. PLoS Pathog 2014; 10:e1004321. [PMID: 25144274 PMCID: PMC4140854 DOI: 10.1371/journal.ppat.1004321] [Citation(s) in RCA: 179] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Accepted: 07/08/2014] [Indexed: 02/06/2023] Open
Abstract
Etiological agents of acute, persistent, or relapsing clinical infections are often refractory to antibiotics due to multidrug resistance and/or antibiotic tolerance. Pseudomonas aeruginosa is an opportunistic Gram-negative bacterial pathogen that causes recalcitrant and severe acute chronic and persistent human infections. Here, we target the MvfR-regulated P. aeruginosa quorum sensing (QS) virulence pathway to isolate robust molecules that specifically inhibit infection without affecting bacterial growth or viability to mitigate selective resistance. Using a whole-cell high-throughput screen (HTS) and structure-activity relationship (SAR) analysis, we identify compounds that block the synthesis of both pro-persistence and pro-acute MvfR-dependent signaling molecules. These compounds, which share a benzamide-benzimidazole backbone and are unrelated to previous MvfR-regulon inhibitors, bind the global virulence QS transcriptional regulator, MvfR (PqsR); inhibit the MvfR regulon in multi-drug resistant isolates; are active against P. aeruginosa acute and persistent murine infections; and do not perturb bacterial growth. In addition, they are the first compounds identified to reduce the formation of antibiotic-tolerant persister cells. As such, these molecules provide for the development of next-generation clinical therapeutics to more effectively treat refractory and deleterious bacterial-human infections. Antibiotic resistant and tolerant bacterial pathogens are responsible for acute, chronic and persistent human infections recalcitrant to any current treatments. Therefore, there is an urgent need to identify new antimicrobial drugs that will help circumvent the current antibiotic resistance crisis. Bacterial pathogens often develop resistance to antibiotic drugs that target bacterial growth or viability. In contrast, strategies that specifically target virulence pathways non-essential for growth could limit selective resistance, and thus are candidates for the development of next-generation antimicrobial therapeutics. In this study we target the bacterial communication system MvfR (PqsR), which is known to control virulence of the opportunistic bacterial pathogen Pseudomonas aeruginosa. We identified and improved upon new small molecules that effectively silence the MvfR communication system, and as a result block P. aeruginosa virulence both in vitro and in vivo. Moreover, these new compounds are the first known to restrict the ability of bacteria to form antibiotic-tolerant cells and consequently proved to be very effective at preventing persistent infection in a mammalian infection model. Because of their ability to simultaneously block acute and persistent infections, these new molecules may provide a very strong basis for the development of next generation antimicrobials.
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Affiliation(s)
- Melissa Starkey
- Department of Surgery, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, United States of America
- Shriners Hospitals for Children Boston, Boston, Massachusetts, United States of America
| | | | - Damien Maura
- Department of Surgery, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, United States of America
- Shriners Hospitals for Children Boston, Boston, Massachusetts, United States of America
| | - Arunava Bandyopadhaya
- Department of Surgery, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, United States of America
- Shriners Hospitals for Children Boston, Boston, Massachusetts, United States of America
| | - Biljana Lesic
- Department of Surgery, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, United States of America
- Shriners Hospitals for Children Boston, Boston, Massachusetts, United States of America
| | - Jianxin He
- Department of Surgery, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, United States of America
- Shriners Hospitals for Children Boston, Boston, Massachusetts, United States of America
| | - Tomoe Kitao
- Department of Surgery, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, United States of America
- Shriners Hospitals for Children Boston, Boston, Massachusetts, United States of America
| | - Valeria Righi
- NMR Surgical Laboratory, Department of Surgery, Massachusetts General and Shriners Hospitals, Harvard Medical School, Boston, Massachusetts, United States of America
- Athinoula A. Martinos Center of Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Boston, Massachusetts, United States of America
| | - Sylvain Milot
- INRS-Institut Armand Frappier, Laval, Québec, Canada
| | - Aria Tzika
- NMR Surgical Laboratory, Department of Surgery, Massachusetts General and Shriners Hospitals, Harvard Medical School, Boston, Massachusetts, United States of America
- Athinoula A. Martinos Center of Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Boston, Massachusetts, United States of America
| | - Laurence Rahme
- Department of Surgery, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, United States of America
- Shriners Hospitals for Children Boston, Boston, Massachusetts, United States of America
- * E-mail:
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327
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Rampioni G, Leoni L, Williams P. The art of antibacterial warfare: Deception through interference with quorum sensing–mediated communication. Bioorg Chem 2014; 55:60-8. [DOI: 10.1016/j.bioorg.2014.04.005] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Revised: 04/09/2014] [Accepted: 04/11/2014] [Indexed: 01/02/2023]
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328
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Abstract
The study by Dulcey and colleagues in this issue of Chemistry & Biology changes our perception of the pathway of 2-alkyl-4-hydroxyquinoline biosynthesis by the opportunistic pathogen Pseudomonas aeruginosa and suggests that the biosynthetic protein complex PqsBC is a potential antibacterial target.
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329
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Dougherty K, Smith BA, Moore AF, Maitland S, Fanger C, Murillo R, Baltrus DA. Multiple phenotypic changes associated with large-scale horizontal gene transfer. PLoS One 2014; 9:e102170. [PMID: 25048697 PMCID: PMC4105467 DOI: 10.1371/journal.pone.0102170] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Accepted: 06/16/2014] [Indexed: 12/22/2022] Open
Abstract
Horizontal gene transfer often leads to phenotypic changes within recipient organisms independent of any immediate evolutionary benefits. While secondary phenotypic effects of horizontal transfer (i.e., changes in growth rates) have been demonstrated and studied across a variety of systems using relatively small plasmids and phage, little is known about the magnitude or number of such costs after the transfer of larger regions. Here we describe numerous phenotypic changes that occur after a large-scale horizontal transfer event (∼1 Mb megaplasmid) within Pseudomonas stutzeri including sensitization to various stresses as well as changes in bacterial behavior. These results highlight the power of horizontal transfer to shift pleiotropic relationships and cellular networks within bacterial genomes. They also provide an important context for how secondary effects of transfer can bias evolutionary trajectories and interactions between species. Lastly, these results and system provide a foundation to investigate evolutionary consequences in real time as newly acquired regions are ameliorated and integrated into new genomic contexts.
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Affiliation(s)
- Kevin Dougherty
- School of Plant Sciences, University of Arizona, Tucson, Arizona, United States of America
| | - Brian A. Smith
- School of Plant Sciences, University of Arizona, Tucson, Arizona, United States of America
| | - Autumn F. Moore
- School of Plant Sciences, University of Arizona, Tucson, Arizona, United States of America
| | - Shannon Maitland
- School of Plant Sciences, University of Arizona, Tucson, Arizona, United States of America
| | - Chris Fanger
- School of Plant Sciences, University of Arizona, Tucson, Arizona, United States of America
| | - Rachel Murillo
- School of Plant Sciences, University of Arizona, Tucson, Arizona, United States of America
| | - David A. Baltrus
- School of Plant Sciences, University of Arizona, Tucson, Arizona, United States of America
- * E-mail:
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330
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Alkaloids: an overview of their antibacterial, antibiotic-enhancing and antivirulence activities. Int J Antimicrob Agents 2014; 44:377-86. [PMID: 25130096 DOI: 10.1016/j.ijantimicag.2014.06.001] [Citation(s) in RCA: 336] [Impact Index Per Article: 33.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Accepted: 06/20/2014] [Indexed: 11/22/2022]
Abstract
With reports of pandrug-resistant bacteria causing untreatable infections, the need for new antibacterial therapies is more pressing than ever. Alkaloids are a large and structurally diverse group of compounds that have served as scaffolds for important antibacterial drugs such as metronidazole and the quinolones. In this review, we highlight other alkaloids with development potential. Natural, semisynthetic and synthetic alkaloids of all classes are considered, looking first at those with direct antibacterial activity and those with antibiotic-enhancing activity. Potent examples include CJ-13,136, a novel actinomycete-derived quinolone alkaloid with a minimum inhibitory concentration of 0.1 ng/mL against Helicobacter pylori, and squalamine, a polyamine alkaloid from the dogfish shark that renders Gram-negative pathogens 16- to >32-fold more susceptible to ciprofloxacin. Where available, information on toxicity, structure-activity relationships, mechanisms of action and in vivo activity is presented. The effects of alkaloids on virulence gene regulatory systems such as quorum sensing and virulence factors such as sortases, adhesins and secretion systems are also described. The synthetic isoquinoline alkaloid virstatin, for example, inhibits the transcriptional regulator ToxT in Vibrio cholerae, preventing expression of cholera toxin and fimbriae and conferring in vivo protection against intestinal colonisation. The review concludes with implications and limitations of the described research and directions for future research.
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331
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Salje J. A single-cell imaging screen reveals multiple effects of secreted small molecules on bacteria. Microbiologyopen 2014; 3:426-36. [PMID: 24910069 PMCID: PMC4287172 DOI: 10.1002/mbo3.176] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Revised: 03/25/2014] [Accepted: 04/04/2014] [Indexed: 12/14/2022] Open
Abstract
Bacteria cells exist in close proximity to other cells of both the same and different species. Bacteria secrete a large number of different chemical species, and the local concentrations of these compounds at the surfaces of nearby cells may reach very high levels. It is fascinating to imagine how individual cells might sense and respond to the complex mix of signals at their surface. However, it is difficult to measure exactly what the local environmental composition looks like, or what the effects of individual compounds on nearby cells are. Here, an electron microscopy imaging screen was designed that would detect morphological changes induced by secreted small molecules. This differs from conventional approaches by detecting structural changes in individual cells rather than gene expression or growth rate changes at the population level. For example, one of the changes detected here was an increase in outer membrane vesicle production, which does not necessarily correspond to a change in gene expression. This initial study focussed on Pseudomonas aeruginosa, Escherichia coli, and Burkholderia dolosa, and revealed an intriguing range of effects of secreted small molecules on cells both within and between species.
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Affiliation(s)
- Jeanne Salje
- Harvard Medical School, 200 Longwood Avenue, Boston, Massachusetts, 02115
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332
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Ye L, Cornelis P, Guillemyn K, Ballet S, Christophersen C, Hammerich O. Structure Revision of N-Mercapto-4-formylcarbostyril Produced by Pseudomonas fluorescens G308 to 2-(2-Hydroxyphenyl)thiazole-4-carbaldehyde [aeruginaldehyde]. Nat Prod Commun 2014. [DOI: 10.1177/1934578x1400900615] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
An antibiotic substance isolated from Pseudomonas fluorescens strain G308 was earlier assigned the structure of N-mercapto-4-formylcarbostyril, but computational predictions of the 1H and 13C NMR magnetic shielding tensors show this structure to be incompatible with the published spectroscopic data. The same is true for six quinoline derivatives related to N-mercapto-4-formylcarbostyril by permutation of the O and S atoms. In contrast, 2-(2-hydroxyphenyl)thiazole-4-carbaldehyde [aeruginaldehyde], isolated from Pseudomonas protegens Pf-5, together with the reduced derivative aeruginol, displays spectroscopic data identical with those of the alleged carbostyril derivative. In addition, the published 1H and 13C NMR data are in agreement with those calculated for aeruginaldehyde. We propose that aeruginaldehyde and aeruginol originate from the non-ribosomal peptide synthetase enzymes involved in the siderophores enantio-pyochelin (or pyochelin) biosynthetic pathways.
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Affiliation(s)
- Lumeng Ye
- VIB Structural Biology Brussels and Department of Bioengineering Sciences, Research Group Microbiology, Vrije Universiteit Brussel, Pleinlaan 2, B-1050, Brussels, Belgium
| | - Pierre Cornelis
- VIB Structural Biology Brussels and Department of Bioengineering Sciences, Research Group Microbiology, Vrije Universiteit Brussel, Pleinlaan 2, B-1050, Brussels, Belgium
| | - Karel Guillemyn
- Laboratory of Organic Chemistry, Vrije Universiteit Brussel, Pleinlaan 2, B-1050, Brussel, Belgium
| | - Steven Ballet
- Laboratory of Organic Chemistry, Vrije Universiteit Brussel, Pleinlaan 2, B-1050, Brussel, Belgium
| | - Carsten Christophersen
- Department of Systems Biology, Technical University of Denmark, Søltofts Plads, DK-2800, Lyngby, Denmark
| | - Ole Hammerich
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark
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333
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Elgorashe REE, Idris AM, Abdelrahman MA, Saeed AEM. Facile assay method for norfloxacin and ciprofloxacin by sequential injection chromatography. ACTA CHROMATOGR 2014. [DOI: 10.1556/achrom.26.2014.2.9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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334
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Hutter MC, Brengel C, Negri M, Henn C, Zimmer C, Hartmann RW, Empting M, Steinbach A. Mechanistic details for anthraniloyl transfer in PqsD: the initial step in HHQ biosynthesis. J Mol Model 2014; 20:2255. [PMID: 24842325 DOI: 10.1007/s00894-014-2255-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Accepted: 04/21/2014] [Indexed: 11/25/2022]
Abstract
PqsD mediates the conversion of anthraniloyl-coenzyme A (ACoA) to 2-heptyl-4-hydroxyquinoline (HHQ), a precursor of the Pseudomonas quinolone signal (PQS) molecule. Due to the role of the quinolone signaling pathway of Pseudomonas aeruginosa in the expression of several virulence factors and biofilm formation, PqsD is a potential target for controlling this nosocomial pathogen, which exhibits a low susceptibility to standard antibiotics. PqsD belongs to the β-ketoacyl-ACP synthase family and is similar in structure to homologous FabH enzymes in E. coli and Mycobacterium tuberculosis. Here, we used molecular dynamics simulations to obtain the structural position of the substrate ACoA in the binding pocket of PqsD, and semiempirical molecular orbital calculations to study the reaction mechanism for the catalytic cleavage of ACoA. Our findings suggest a nucleophilic attack of the deprotonated sulfur of Cys112 at the carbonyl carbon of ACoA and a switch in the protonation pattern of His257 whereby Nδ is protonated and the proton of Nε is shifted to the sulfur of CoA during the reaction. This is in agreement with the experimentally determined decreased catalytic activity of the Cys112Ser mutant, whereas the Cys112Ala, His257Phe, and Asn287Ala mutants are all inactive. ESI mass-spectrometric measurements of the Asn287Ala mutant show that anthraniloyl remains covalently bound to Cys112, thus further supporting the inference from our computed mechanism that Asn287 does not take part in the cleavage of ACoA. Since this mutant is inactive, we suggest instead that Asn287 must play an essential role in the subsequent formation of HHQ in vitro.
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Affiliation(s)
- Michael C Hutter
- Center for Bioinformatics, Saarland University, Campus Building E2.1, 66123, Saarbrücken, Germany,
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335
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Microbial biosynthesis of the anticoagulant precursor 4-hydroxycoumarin. Nat Commun 2014; 4:2603. [PMID: 24129598 DOI: 10.1038/ncomms3603] [Citation(s) in RCA: 108] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Accepted: 09/12/2013] [Indexed: 01/06/2023] Open
Abstract
4-Hydroxycoumarin (4HC) type anticoagulants (for example, warfarin) are known to have a significant role in the treatment of thromboembolic diseases--a leading cause of patient morbidity and mortality worldwide. 4HC serves as an immediate precursor of these synthetic anticoagulants. Although 4HC was initially identified as a naturally occurring product, its biosynthesis has not been fully elucidated. Here we present the design, validation, in vitro diagnosis and optimization of an artificial biosynthetic mechanism leading to the microbial biosynthesis of 4HC. Remarkably, function-based enzyme bioprospecting leads to the identification of a characteristic FabH-like quinolone synthase from Pseudomonas aeruginosa with high efficiency on the 4HC-forming reaction, which promotes the high-level de novo biosynthesis of 4HC in Escherichia coli (~500 mg l⁻¹ in shake flasks) and further in situ semisynthesis of warfarin. This work has the potential to be scaled-up for microbial production of 4HC and opens up the possibility of biosynthesizing diverse coumarin molecules with pharmaceutical importance.
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336
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Synthetic Interaction between the TipN Polarity Factor and an AcrAB-Family Efflux Pump Implicates Cell Polarity in Bacterial Drug Resistance. ACTA ACUST UNITED AC 2014; 21:657-65. [DOI: 10.1016/j.chembiol.2014.02.018] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Revised: 02/04/2014] [Accepted: 02/28/2014] [Indexed: 11/23/2022]
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337
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Impact of a transposon insertion in phzF2 on the specialized metabolite production and interkingdom interactions of Pseudomonas aeruginosa. J Bacteriol 2014; 196:1683-93. [PMID: 24532776 DOI: 10.1128/jb.01258-13] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
In microbiology, gene disruption and subsequent experiments often center on phenotypic changes caused by one class of specialized metabolites (quorum sensors, virulence factors, or natural products), disregarding global downstream metabolic effects. With the recent development of mass spectrometry-based methods and technologies for microbial metabolomics investigations, it is now possible to visualize global production of diverse classes of microbial specialized metabolites simultaneously. Using imaging mass spectrometry (IMS) applied to the analysis of microbiology experiments, we can observe the effects of mutations, knockouts, insertions, and complementation on the interactive metabolome. In this study, a combination of IMS and liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to visualize the impact on specialized metabolite production of a transposon insertion into a Pseudomonas aeruginosa phenazine biosynthetic gene, phzF2. The disruption of phenazine biosynthesis led to broad changes in specialized metabolite production, including loss of pyoverdine production. This shift in specialized metabolite production significantly alters the metabolic outcome of an interaction with Aspergillus fumigatus by influencing triacetylfusarinine production.
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338
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Ortori CA, Halliday N, Cámara M, Williams P, Barrett DA. LC-MS/MS quantitative analysis of quorum sensing signal molecules. Methods Mol Biol 2014; 1149:255-70. [PMID: 24818911 DOI: 10.1007/978-1-4939-0473-0_21] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Extracts taken from spent growth media from Pseudomonas aeruginosa can be analyzed for N-acyl-L-homoserine lactones and 2-alkyl-4-(1H)-quinolones (AQs), including the known quorum sensing signalling molecules of P. aeruginosa, in a specific and sensitive manner by liquid chromatography coupled with tandem mass spectrometric detection. This analysis can be conducted in a quantitative manner by comparison with matrix-matched calibration samples.
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Affiliation(s)
- Catharine A Ortori
- Centre for Analytical Bioscience, School of Pharmacy, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
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339
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Holm A, Vikström E. Quorum sensing communication between bacteria and human cells: signals, targets, and functions. FRONTIERS IN PLANT SCIENCE 2014; 5:309. [PMID: 25018766 PMCID: PMC4071818 DOI: 10.3389/fpls.2014.00309] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Accepted: 06/10/2014] [Indexed: 05/10/2023]
Abstract
Both direct and long-range interactions between pathogenic Pseudomonas aeruginosa bacteria and their eukaryotic hosts are important in the outcome of infections. For cell-to-cell communication, these bacteria employ the quorum sensing (QS) system to pass on information of the density of the bacterial population and collectively switch on virulence factor production, biofilm formation, and resistance development. Thus, QS allows bacteria to behave as a community to perform tasks which would be impossible for individual cells, e.g., to overcome defense and immune systems and establish infections in higher organisms. This review highlights these aspects of QS and our own recent research on how P. aeruginosa communicates with human cells using the small QS signal molecules N-acyl homoserine lactones (AHL). We focus on how this conversation changes the behavior and function of neutrophils, macrophages, and epithelial cells and on how the signaling machinery in human cells responsible for the recognition of AHL. Understanding the bacteria-host relationships at both cellular and molecular levels is essential for the identification of new targets and for the development of novel strategies to fight bacterial infections in the future.
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Affiliation(s)
| | - Elena Vikström
- *Correspondence: Elena Vikström, Division of Medical Microbiology, Department of Clinical and Experimental Medicine, Faculty of Health Sciences, Linköping University, Linköping SE-58185, Sweden e-mail:
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340
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Que YA, Hazan R, Strobel B, Maura D, He J, Kesarwani M, Panopoulos P, Tsurumi A, Giddey M, Wilhelmy J, Mindrinos MN, Rahme LG. A quorum sensing small volatile molecule promotes antibiotic tolerance in bacteria. PLoS One 2013; 8:e80140. [PMID: 24367477 PMCID: PMC3868577 DOI: 10.1371/journal.pone.0080140] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2013] [Accepted: 09/30/2013] [Indexed: 01/10/2023] Open
Abstract
Bacteria can be refractory to antibiotics due to a sub-population of dormant cells, called persisters that are highly tolerant to antibiotic exposure. The low frequency and transience of the antibiotic tolerant “persister” trait has complicated elucidation of the mechanism that controls antibiotic tolerance. In this study, we show that 2’ Amino-acetophenone (2-AA), a poorly studied but diagnostically important small, volatile molecule produced by the recalcitrant gram-negative human pathogen Pseudomonas aeruginosa, promotes antibiotic tolerance in response to quorum-sensing (QS) signaling. Our results show that 2-AA mediated persister cell accumulation occurs via alteration of the expression of genes involved in the translational capacity of the cell, including almost all ribosomal protein genes and other translation-related factors. That 2-AA promotes persisters formation also in other emerging multi-drug resistant pathogens, including the non 2-AA producer Acinetobacter baumannii implies that 2-AA may play an important role in the ability of gram-negative bacteria to tolerate antibiotic treatments in polymicrobial infections. Given that the synthesis, excretion and uptake of QS small molecules is a common hallmark of prokaryotes, together with the fact that the translational machinery is highly conserved, we posit that modulation of the translational capacity of the cell via QS molecules, may be a general, widely distributed mechanism that promotes antibiotic tolerance among prokaryotes.
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Affiliation(s)
- Yok-Ai Que
- Department of Surgery, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, United States of America
- Shriners Hospitals for Children Boston, Boston, Massachusetts, United States of America
| | - Ronen Hazan
- Department of Surgery, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, United States of America
- Shriners Hospitals for Children Boston, Boston, Massachusetts, United States of America
- IYAR, The Israeli Institute for Advanced Research, Israel
- Institute of Dental Sciences and School of Dental Medicine, Hebrew University, Jerusalem, Israel
| | - Benjamin Strobel
- Department of Surgery, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, United States of America
- Shriners Hospitals for Children Boston, Boston, Massachusetts, United States of America
| | - Damien Maura
- Department of Surgery, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, United States of America
- Shriners Hospitals for Children Boston, Boston, Massachusetts, United States of America
| | - Jianxin He
- Department of Surgery, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, United States of America
- Shriners Hospitals for Children Boston, Boston, Massachusetts, United States of America
| | - Meenu Kesarwani
- Department of Surgery, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, United States of America
- Shriners Hospitals for Children Boston, Boston, Massachusetts, United States of America
| | - Panagiotis Panopoulos
- Department of Surgery, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, United States of America
- Shriners Hospitals for Children Boston, Boston, Massachusetts, United States of America
| | - Amy Tsurumi
- Department of Surgery, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, United States of America
- Shriners Hospitals for Children Boston, Boston, Massachusetts, United States of America
| | - Marlyse Giddey
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Julie Wilhelmy
- Stanford Genome Technology Center, Stanford University, Palo Alto, California, United States of America
| | - Michael N. Mindrinos
- Stanford Genome Technology Center, Stanford University, Palo Alto, California, United States of America
| | - Laurence G. Rahme
- Department of Surgery, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, United States of America
- Shriners Hospitals for Children Boston, Boston, Massachusetts, United States of America
- * E-mail:
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341
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Dulcey CE, Dekimpe V, Fauvelle DA, Milot S, Groleau MC, Doucet N, Rahme LG, Lépine F, Déziel E. The end of an old hypothesis: the pseudomonas signaling molecules 4-hydroxy-2-alkylquinolines derive from fatty acids, not 3-ketofatty acids. ACTA ACUST UNITED AC 2013; 20:1481-91. [PMID: 24239007 DOI: 10.1016/j.chembiol.2013.09.021] [Citation(s) in RCA: 104] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Revised: 08/23/2013] [Accepted: 09/04/2013] [Indexed: 02/07/2023]
Abstract
Groups of pathogenic bacteria use diffusible signals to regulate their virulence in a concerted manner. Pseudomonas aeruginosa uses 4-hydroxy-2-alkylquinolines (HAQs), including 4-hydroxy-2-heptylquinoline (HHQ) and 3,4-dihydroxy-2-heptylquinoline (PQS), as unique signals. We demonstrate that octanoic acid is directly incorporated into HHQ. This finding rules out the long-standing hypothesis that 3-ketofatty acids are the precursors of HAQs. We found that HAQ biosynthesis, which requires the PqsABCD enzymes, proceeds by a two-step pathway: (1) PqsD mediates the synthesis of 2-aminobenzoylacetate (2-ABA) from anthraniloyl-coenzyme A (CoA) and malonyl-CoA, then (2) the decarboxylating coupling of 2-ABA to an octanoate group linked to PqsC produces HHQ, the direct precursor of PQS. PqsB is tightly associated with PqsC and required for the second step. This finding uncovers promising targets for the development of specific antivirulence drugs to combat this opportunistic pathogen.
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Affiliation(s)
- Carlos Eduardo Dulcey
- INRS-Institut Armand-Frappier, Université du Québec, 531 Boulevard des Prairies, Laval, QC H7V 1B7, Canada
| | - Valérie Dekimpe
- INRS-Institut Armand-Frappier, Université du Québec, 531 Boulevard des Prairies, Laval, QC H7V 1B7, Canada
| | - David-Alexandre Fauvelle
- INRS-Institut Armand-Frappier, Université du Québec, 531 Boulevard des Prairies, Laval, QC H7V 1B7, Canada
| | - Sylvain Milot
- INRS-Institut Armand-Frappier, Université du Québec, 531 Boulevard des Prairies, Laval, QC H7V 1B7, Canada
| | - Marie-Christine Groleau
- INRS-Institut Armand-Frappier, Université du Québec, 531 Boulevard des Prairies, Laval, QC H7V 1B7, Canada
| | - Nicolas Doucet
- INRS-Institut Armand-Frappier, Université du Québec, 531 Boulevard des Prairies, Laval, QC H7V 1B7, Canada
| | - Laurence G Rahme
- Department of Surgery, Massachusetts General Hospital, Harvard Medical School, 50 Blossom Street, Boston, MA 02114, USA
| | - François Lépine
- INRS-Institut Armand-Frappier, Université du Québec, 531 Boulevard des Prairies, Laval, QC H7V 1B7, Canada.
| | - Eric Déziel
- INRS-Institut Armand-Frappier, Université du Québec, 531 Boulevard des Prairies, Laval, QC H7V 1B7, Canada.
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342
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Aksenov AV, Smirnov AN, Aksenov NA, Aksenova IV, Frolova LV, Kornienko A, Magedov IV, Rubin M. Metal-free transannulation reaction of indoles with nitrostyrenes: a simple practical synthesis of 3-substituted 2-quinolones. Chem Commun (Camb) 2013; 49:9305-7. [PMID: 23999797 PMCID: PMC4945960 DOI: 10.1039/c3cc45696j] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
3-Substituted 2-quinolones are obtained via a novel, metal-free transannulation reaction of 2-substituted indoles with 2-nitroalkenes in polyphosphoric acid. The reaction can be used in conjunction with the Fisher indole synthesis offering a practical three-component heteroannulation methodology to produce 2-quinolones from arylhydrazines, 2-nitroalkenes and acetophenone.
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Affiliation(s)
- Alexander V. Aksenov
- Department of Chemistry, North Caucasus Federal University, 1a Pushkin St., Stavropol 355009, Russian Federation
| | - Alexander N. Smirnov
- Department of Chemistry, North Caucasus Federal University, 1a Pushkin St., Stavropol 355009, Russian Federation
| | - Nicolai A. Aksenov
- Department of Chemistry, North Caucasus Federal University, 1a Pushkin St., Stavropol 355009, Russian Federation
| | - Inna V. Aksenova
- Department of Chemistry, North Caucasus Federal University, 1a Pushkin St., Stavropol 355009, Russian Federation
| | - Liliya V. Frolova
- Department of Chemistry, New Mexico Institute of Mining and Technology, Socorro, NM 87801, USA
| | - Alexander Kornienko
- Department of Chemistry and Biochemistry, Texas State University, San Marcos, TX 78666, USA.
| | - Igor V. Magedov
- Department of Chemistry, New Mexico Institute of Mining and Technology, Socorro, NM 87801, USA
| | - Michael Rubin
- Department of Chemistry, University of Kansas, 1251 Wescoe Hall Dr., Lawrence, KS 66045, USA
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343
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Zhu J, Kaufmann GF. Quo vadis quorum quenching? Curr Opin Pharmacol 2013; 13:688-98. [DOI: 10.1016/j.coph.2013.07.003] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Revised: 06/26/2013] [Accepted: 07/01/2013] [Indexed: 01/27/2023]
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344
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O'Connell KMG, Hodgkinson JT, Sore HF, Welch M, Salmond GPC, Spring DR. Die Bekämpfung multiresistenter Bakterien: aktuelle Strategien zur Entdeckung neuer Antibiotika. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201209979] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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345
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O'Connell KMG, Hodgkinson JT, Sore HF, Welch M, Salmond GPC, Spring DR. Combating Multidrug-Resistant Bacteria: Current Strategies for the Discovery of Novel Antibacterials. Angew Chem Int Ed Engl 2013; 52:10706-33. [DOI: 10.1002/anie.201209979] [Citation(s) in RCA: 310] [Impact Index Per Article: 28.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Revised: 02/25/2013] [Indexed: 11/07/2022]
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346
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Schaadt NS, Steinbach A, Hartmann RW, Helms V. Rule-based regulatory and metabolic model for Quorum sensing in P. aeruginosa. BMC SYSTEMS BIOLOGY 2013; 7:81. [PMID: 23965312 PMCID: PMC3765737 DOI: 10.1186/1752-0509-7-81] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Accepted: 08/09/2013] [Indexed: 12/24/2022]
Abstract
Background In the pathogen P. aeruginosa, the formation of virulence factors is regulated via Quorum sensing signaling pathways. Due to the increasing number of strains that are resistant to antibiotics, there is a high interest to develop novel antiinfectives. In the combat of resistant bacteria, selective blockade of the bacterial cell–to–cell communication (Quorum sensing) has gained special interest as anti–virulence strategy. Here, we modeled the las, rhl, and pqs Quorum sensing systems by a multi–level logical approach to analyze how enzyme inhibitors and receptor antagonists effect the formation of autoinducers and virulence factors. Results Our rule–based simulations fulfill the behavior expected from literature considering the external level of autoinducers. In the presence of PqsBCD inhibitors, the external HHQ and PQS levels are indeed clearly reduced. The magnitude of this effect strongly depends on the inhibition level. However, it seems that the pyocyanin pathway is incomplete. Conclusions To match experimental observations we suggest a modified network topology in which PqsE and PqsR acts as receptors and an autoinducer as ligand that up–regulate pyocyanin in a concerted manner. While the PQS biosynthesis is more appropriate as target to inhibit the HHQ and PQS formation, blocking the receptor PqsR that regulates the biosynthesis reduces the pyocyanin level stronger.
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Affiliation(s)
- Nadine S Schaadt
- Center for Bioinformatics, Saarland University, Campus E2,1, 66123 Saarbrücken, Germany.
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347
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Morris ER, Hall G, Li C, Heeb S, Kulkarni RV, Lovelock L, Silistre H, Messina M, Cámara M, Emsley J, Williams P, Searle MS. Structural rearrangement in an RsmA/CsrA ortholog of Pseudomonas aeruginosa creates a dimeric RNA-binding protein, RsmN. Structure 2013; 21:1659-71. [PMID: 23954502 PMCID: PMC3791407 DOI: 10.1016/j.str.2013.07.007] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Revised: 07/11/2013] [Accepted: 07/14/2013] [Indexed: 12/20/2022]
Abstract
In bacteria, the highly conserved RsmA/CsrA family of RNA-binding proteins functions as global posttranscriptional regulators acting on mRNA translation and stability. Through phenotypic complementation of an rsmA mutant in Pseudomonas aeruginosa, we discovered a family member, termed RsmN. Elucidation of the RsmN crystal structure and that of the complex with a hairpin from the sRNA, RsmZ, reveals a uniquely inserted α helix, which redirects the polypeptide chain to form a distinctly different protein fold to the domain-swapped dimeric structure of RsmA homologs. The overall β sheet structure required for RNA recognition is, however, preserved with compensatory sequence and structure differences, allowing the RsmN dimer to target binding motifs in both structured hairpin loops and flexible disordered RNAs. Phylogenetic analysis indicates that, although RsmN appears unique to P. aeruginosa, homologous proteins with the inserted α helix are more widespread and arose as a consequence of a gene duplication event. Phenotypic complementation identifies a CsrA/RsmA family member from P. aeruginosa Crystallography reveals a dimeric fold for RsmN The RsmN complex was solved with a hairpin motif from the noncoding sRNA RsmZ-2 Details of binding affinity and specificity with target RNA 5′-ANGGAN motifs are revealed
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Affiliation(s)
- Elizabeth R Morris
- School of Chemistry, Centre for Biomolecular Sciences, University of Nottingham, Nottingham NG7 2RD, UK
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348
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Hsu CC, ElNaggar MS, Peng Y, Fang J, Sanchez LM, Mascuch SJ, Møller A, Alazzeh EK, Pikula J, Quinn RA, Zeng Y, Wolfe BE, Dutton RJ, Gerwick L, Zhang L, Liu X, Månsson M, Dorrestein PC. Real-time metabolomics on living microorganisms using ambient electrospray ionization flow-probe. Anal Chem 2013; 85:7014-8. [PMID: 23819546 PMCID: PMC3890442 DOI: 10.1021/ac401613x] [Citation(s) in RCA: 93] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Microorganisms such as bacteria and fungi produce a variety of specialized metabolites that are invaluable for agriculture, biological research, and drug discovery. However, the screening of microbial metabolic output is usually a time-intensive task. Here, we utilize a liquid microjunction surface sampling probe for electrospray ionization-mass spectrometry to extract and ionize metabolite mixtures directly from living microbial colonies grown on soft nutrient agar in Petri-dishes without any sample pretreatment. To demonstrate the robustness of the method, this technique was applied to observe the metabolic output of more than 30 microorganisms, including yeast, filamentous fungi, pathogens, and marine-derived bacteria, that were collected worldwide. Diverse natural products produced from different microbes, including Streptomyces coelicolor , Bacillus subtilis , and Pseudomonas aeruginosa are further characterized.
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Affiliation(s)
- Cheng-Chih Hsu
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA
| | | | - Yao Peng
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA
| | - Jinshu Fang
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA
| | - Laura M. Sanchez
- Skaggs School of Pharmacy and Pharmaceutical Science, University of California, San Diego, La Jolla, CA 92093, USA
| | | | - Amalie Møller
- Department of Systems Biology, Technical University of Denmark, Lyngby, Denmark
| | | | - Jiri Pikula
- University of Veterinary and Pharmaceutical Sciences, Palackeho 1/3, 612 42 Brno, Czech Republic
| | - Robert A. Quinn
- Biology Department, San Diego State University, San Diego, CA 92182, USA
| | - Yi Zeng
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA
| | - Benjamin E. Wolfe
- FAS Center for Systems Biology, Harvard University, Cambridge, MA 02138, USA
| | - Rachel J. Dutton
- FAS Center for Systems Biology, Harvard University, Cambridge, MA 02138, USA
| | - Lena Gerwick
- Scripps Institute of Oceanography, La Jolla, CA 92037, USA
| | - Lixin Zhang
- Institute of Microbiology, Chinese Academy of Science, Beijing 100101, China
| | - Xueting Liu
- Institute of Microbiology, Chinese Academy of Science, Beijing 100101, China
| | - Maria Månsson
- Department of Systems Biology, Technical University of Denmark, Lyngby, Denmark
| | - Pieter C. Dorrestein
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA
- Skaggs School of Pharmacy and Pharmaceutical Science, University of California, San Diego, La Jolla, CA 92093, USA
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349
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Ilangovan A, Fletcher M, Rampioni G, Pustelny C, Rumbaugh K, Heeb S, Cámara M, Truman A, Chhabra SR, Emsley J, Williams P. Structural basis for native agonist and synthetic inhibitor recognition by the Pseudomonas aeruginosa quorum sensing regulator PqsR (MvfR). PLoS Pathog 2013; 9:e1003508. [PMID: 23935486 PMCID: PMC3723537 DOI: 10.1371/journal.ppat.1003508] [Citation(s) in RCA: 151] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Accepted: 06/05/2013] [Indexed: 12/02/2022] Open
Abstract
Bacterial populations co-ordinate gene expression collectively through quorum sensing (QS), a cell-to-cell communication mechanism employing diffusible signal molecules. The LysR-type transcriptional regulator (LTTR) protein PqsR (MvfR) is a key component of alkyl-quinolone (AQ)-dependent QS in Pseudomonas aeruginosa. PqsR is activated by 2-alkyl-4-quinolones including the Pseudomonas quinolone signal (PQS; 2-heptyl-3-hydroxy-4(1H)-quinolone), its precursor 2-heptyl-4-hydroxyquinoline (HHQ) and their C9 congeners, 2-nonyl-3-hydroxy-4(1H)-quinolone (C9-PQS) and 2-nonyl-4-hydroxyquinoline (NHQ). These drive the autoinduction of AQ biosynthesis and the up-regulation of key virulence determinants as a function of bacterial population density. Consequently, PqsR constitutes a potential target for novel antibacterial agents which attenuate infection through the blockade of virulence. Here we present the crystal structures of the PqsR co-inducer binding domain (CBD) and a complex with the native agonist NHQ. We show that the structure of the PqsR CBD has an unusually large ligand-binding pocket in which a native AQ agonist is stabilized entirely by hydrophobic interactions. Through a ligand-based design strategy we synthesized and evaluated a series of 50 AQ and novel quinazolinone (QZN) analogues and measured the impact on AQ biosynthesis, virulence gene expression and biofilm development. The simple exchange of two isosteres (OH for NH2) switches a QZN agonist to an antagonist with a concomitant impact on the induction of bacterial virulence factor production. We also determined the complex crystal structure of a QZN antagonist bound to PqsR revealing a similar orientation in the ligand binding pocket to the native agonist NHQ. This structure represents the first description of an LTTR-antagonist complex. Overall these studies present novel insights into LTTR ligand binding and ligand-based drug design and provide a chemical scaffold for further anti-P. aeruginosa virulence drug development by targeting the AQ receptor PqsR. Populations of bacterial cells collectively co-ordinate their activities through cell-to-cell communication via the production and sensing of signal molecules. This is called quorum sensing (QS) and in many bacteria, QS controls the expression of virulence genes, the products of which damage host tissues. Consequently, QS systems are potential targets for antimicrobial agents which do not kill bacteria but instead block their ability to cause disease. Pseudomonas aeruginosa causes a wide range of human infections and produces an armoury of virulence factors. Since many of these are controlled by alkylquinolone (AQ)-dependent QS, we determined the crystal structure of the AQ receptor (PqsR) in order to visualize the shape of the AQ-binding site and better design PqsR inhibitors which compete for the AQ binding site and so block QS. This work in conjunction with the chemical synthesis of AQ analogues resulted in the discovery of potent quinazolinone inhibitors of PqsR. These blocked AQ and virulence factor production in P. aeruginosa as well as biofilm development. Our studies present novel insights into the structure of PqsR and create further opportunities for target-based antibacterial drug development.
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Affiliation(s)
- Aravindan Ilangovan
- Centre for Biomolecular Sciences, University of Nottingham, University Park, Nottingham, United Kingdom
- School of Molecular Medical Sciences, University of Nottingham, University Park, Nottingham, United Kingdom
- School of Pharmacy, University of Nottingham, University Park, Nottingham, United Kingdom
| | - Matthew Fletcher
- Centre for Biomolecular Sciences, University of Nottingham, University Park, Nottingham, United Kingdom
- School of Molecular Medical Sciences, University of Nottingham, University Park, Nottingham, United Kingdom
| | - Giordano Rampioni
- Centre for Biomolecular Sciences, University of Nottingham, University Park, Nottingham, United Kingdom
- School of Molecular Medical Sciences, University of Nottingham, University Park, Nottingham, United Kingdom
| | - Christian Pustelny
- Centre for Biomolecular Sciences, University of Nottingham, University Park, Nottingham, United Kingdom
- School of Molecular Medical Sciences, University of Nottingham, University Park, Nottingham, United Kingdom
| | - Kendra Rumbaugh
- Department of Surgery, University of Texas, Lubbock, Texas, United States of America
| | - Stephan Heeb
- Centre for Biomolecular Sciences, University of Nottingham, University Park, Nottingham, United Kingdom
- School of Molecular Medical Sciences, University of Nottingham, University Park, Nottingham, United Kingdom
| | - Miguel Cámara
- Centre for Biomolecular Sciences, University of Nottingham, University Park, Nottingham, United Kingdom
- School of Molecular Medical Sciences, University of Nottingham, University Park, Nottingham, United Kingdom
| | - Alex Truman
- Centre for Biomolecular Sciences, University of Nottingham, University Park, Nottingham, United Kingdom
- School of Molecular Medical Sciences, University of Nottingham, University Park, Nottingham, United Kingdom
| | - Siri Ram Chhabra
- Centre for Biomolecular Sciences, University of Nottingham, University Park, Nottingham, United Kingdom
- School of Molecular Medical Sciences, University of Nottingham, University Park, Nottingham, United Kingdom
| | - Jonas Emsley
- Centre for Biomolecular Sciences, University of Nottingham, University Park, Nottingham, United Kingdom
- School of Pharmacy, University of Nottingham, University Park, Nottingham, United Kingdom
| | - Paul Williams
- Centre for Biomolecular Sciences, University of Nottingham, University Park, Nottingham, United Kingdom
- School of Molecular Medical Sciences, University of Nottingham, University Park, Nottingham, United Kingdom
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Bala A, Gupta RK, Chhibber S, Harjai K. Detection and quantification of quinolone signalling molecule: A third quorum sensing molecule of Pseudomonas aeruginosa by high performance-thin layer chromatography. J Chromatogr B Analyt Technol Biomed Life Sci 2013; 930:30-5. [DOI: 10.1016/j.jchromb.2013.04.027] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2012] [Revised: 04/16/2013] [Accepted: 04/21/2013] [Indexed: 01/27/2023]
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