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Bacterial Nucleoside Catabolism Controls Quorum Sensing and Commensal-to-Pathogen Transition in the Drosophila Gut. Cell Host Microbe 2020; 27:345-357.e6. [DOI: 10.1016/j.chom.2020.01.025] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Revised: 01/03/2020] [Accepted: 01/29/2020] [Indexed: 02/08/2023]
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Saurav K, Borbone N, Burgsdorf I, Teta R, Caso A, Bar-Shalom R, Esposito G, Britstein M, Steindler L, Costantino V. Identification of Quorum Sensing Activators and Inhibitors in The Marine Sponge Sarcotragus spinosulus. Mar Drugs 2020; 18:md18020127. [PMID: 32093216 PMCID: PMC7074164 DOI: 10.3390/md18020127] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 02/11/2020] [Accepted: 02/18/2020] [Indexed: 12/27/2022] Open
Abstract
Marine sponges, a well-documented prolific source of natural products, harbor highly diverse microbial communities. Their extracts were previously shown to contain quorum sensing (QS) signal molecules of the N-acyl homoserine lactone (AHL) type, known to orchestrate bacterial gene regulation. Some bacteria and eukaryotic organisms are known to produce molecules that can interfere with QS signaling, thus affecting microbial genetic regulation and function. In the present study, we established the production of both QS signal molecules as well as QS inhibitory (QSI) molecules in the sponge species Sarcotragus spinosulus. A total of eighteen saturated acyl chain AHLs were identified along with six unsaturated acyl chain AHLs. Bioassay-guided purification led to the isolation of two brominated metabolites with QSI activity. The structures of these compounds were elucidated by comparative spectral analysis of 1HNMR and HR-MS data and were identified as 3-bromo-4-methoxyphenethylamine (1) and 5,6-dibromo-N,N-dimethyltryptamine (2). The QSI activity of compounds 1 and 2 was evaluated using reporter gene assays for long- and short-chain AHL signals (Escherichia coli pSB1075 and E. coli pSB401, respectively). QSI activity was further confirmed by measuring dose-dependent inhibition of proteolytic activity and pyocyanin production in Pseudomonas aeruginosa PAO1. The obtained results show the coexistence of QS and QSI in S. spinosulus, a complex signal network that may mediate the orchestrated function of the microbiome within the sponge holobiont.
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Affiliation(s)
- Kumar Saurav
- Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, Mt. Carmel 31905, Haifa, Israel; (K.S.); (I.B.); (R.B.-S.); (M.B.); (L.S.)
- The Blue Chemistry Lab, Dipartimento di Farmacia, Università degli Studi di Napoli Federico II, Via D. Montesano 49, 80131, Napoli, Italy; (N.B.); (R.T.); (A.C.); (G.E.)
- Laboratory of Algal Biotechnology-Centre Algatech, Institute of Microbiology of the Czech Academy of Sciences, Opatovickýmlýn, Novohradská 237, 379 81 Třeboň, Czech Republic
| | - Nicola Borbone
- The Blue Chemistry Lab, Dipartimento di Farmacia, Università degli Studi di Napoli Federico II, Via D. Montesano 49, 80131, Napoli, Italy; (N.B.); (R.T.); (A.C.); (G.E.)
| | - Ilia Burgsdorf
- Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, Mt. Carmel 31905, Haifa, Israel; (K.S.); (I.B.); (R.B.-S.); (M.B.); (L.S.)
| | - Roberta Teta
- The Blue Chemistry Lab, Dipartimento di Farmacia, Università degli Studi di Napoli Federico II, Via D. Montesano 49, 80131, Napoli, Italy; (N.B.); (R.T.); (A.C.); (G.E.)
| | - Alessia Caso
- The Blue Chemistry Lab, Dipartimento di Farmacia, Università degli Studi di Napoli Federico II, Via D. Montesano 49, 80131, Napoli, Italy; (N.B.); (R.T.); (A.C.); (G.E.)
| | - Rinat Bar-Shalom
- Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, Mt. Carmel 31905, Haifa, Israel; (K.S.); (I.B.); (R.B.-S.); (M.B.); (L.S.)
| | - Germana Esposito
- The Blue Chemistry Lab, Dipartimento di Farmacia, Università degli Studi di Napoli Federico II, Via D. Montesano 49, 80131, Napoli, Italy; (N.B.); (R.T.); (A.C.); (G.E.)
| | - Maya Britstein
- Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, Mt. Carmel 31905, Haifa, Israel; (K.S.); (I.B.); (R.B.-S.); (M.B.); (L.S.)
| | - Laura Steindler
- Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, Mt. Carmel 31905, Haifa, Israel; (K.S.); (I.B.); (R.B.-S.); (M.B.); (L.S.)
| | - Valeria Costantino
- The Blue Chemistry Lab, Dipartimento di Farmacia, Università degli Studi di Napoli Federico II, Via D. Montesano 49, 80131, Napoli, Italy; (N.B.); (R.T.); (A.C.); (G.E.)
- Correspondence: ; Tel.: +39-081-678-504
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Vogel J, Wakker-Havinga M, Setroikromo R, Quax WJ. Immobilized Acylase PvdQ Reduces Pseudomonas aeruginosa Biofilm Formation on PDMS Silicone. Front Chem 2020; 8:54. [PMID: 32117880 PMCID: PMC7012999 DOI: 10.3389/fchem.2020.00054] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 01/17/2020] [Indexed: 11/13/2022] Open
Abstract
The bacterial biofilm plays a key role in nosocomial infections, especially those related to medical devices in sustained contact with patients. The active dispersion of bacterial cells out of biofilms acts as a reservoir for infectious diseases. The formation of such biofilms is a highly complex process, which is coordinated by many regulatory mechanisms of the pathogen including quorum sensing (QS). Many bacteria coordinate the expression of key virulence factors dependent on their population density through QS. The inhibition of this system is called quorum quenching (QQ). Thus, preventing the development of biofilms is considered a promising approach to prevent the development of hard to treat infections. Enzymatic QQ is the concept of interfering with the QS system of bacteria outside the cell. PvdQ is an acylase with an N-terminal nucleophile (Ntn-hydrolase) that is a part of the pyoverdine gene cluster (pvd). It is able to cleave irreversibly the amide bond of long chain N-acyl homoserine lactones (AHL) rendering them inactive. Long chain AHLs are the main signaling molecule in the QS system of the gram-negative pathogen Pseudomonas aeruginosa PA01, which is known for surface-associated biofilms on indwelling catheters and is also the cause of catheter-associated urinary tract infections. Furthermore, PA01 is a well characterized pathogen with respect to QS as well as QQ. In this study, we immobilized the acylase PvdQ on polydimethylsiloxane silicone (PDMS), creating a surface with quorum quenching properties. The goal is to control infections by minimizing the colonization of indwelling medical devices such as urinary catheters or intravascular catheters. The enzyme activity was confirmed by testing the degradation of the main auto-inducer that mediates QS in P. aeruginosa. In this article we report for the first time a successful immobilization of the quorum quenching acylase PvdQ on PDMS silicone. We could show that immobilized PvdQ retained its activity after the coating procedure and showed a 6-fold reduction of the auto-inducer 3-oxo-C12 in a biosensor setup. Further we report significant reduction of a P. aeruginosa PA01 biofilm on a coated PDMS surface compared to the same untreated material.
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Affiliation(s)
- Jan Vogel
- Chemical and Pharmaceutical Biology Department, University of Groningen, Groningen, Netherlands
| | - Marijke Wakker-Havinga
- Chemical and Pharmaceutical Biology Department, University of Groningen, Groningen, Netherlands
| | - Rita Setroikromo
- Chemical and Pharmaceutical Biology Department, University of Groningen, Groningen, Netherlands
| | - Wim J Quax
- Chemical and Pharmaceutical Biology Department, University of Groningen, Groningen, Netherlands
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Ishaque NM, Burgsdorf I, Limlingan Malit JJ, Saha S, Teta R, Ewe D, Kannabiran K, Hrouzek P, Steindler L, Costantino V, Saurav K. Isolation, Genomic and Metabolomic Characterization of Streptomyces tendae VITAKN with Quorum Sensing Inhibitory Activity from Southern India. Microorganisms 2020; 8:E121. [PMID: 31963137 PMCID: PMC7023471 DOI: 10.3390/microorganisms8010121] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 01/12/2020] [Accepted: 01/13/2020] [Indexed: 01/11/2023] Open
Abstract
Streptomyces are among the most promising genera in terms of production ability to biosynthesize a variety of bioactive secondary metabolites with pharmaceutical interest. Coinciding with the increase in genomic sequencing of these bacteria, mining of their genomes for biosynthetic gene clusters (BGCs) has become a routine component of natural product discovery. Herein, we describe the isolation and characterization of a Streptomyces tendae VITAKN with quorum sensing inhibitory (QSI) activity that was isolated from southern coastal part of India. The nearly complete genome consists of 8,621,231bp with a GC content of 72.2%. Sequence similarity networks of the BGCs detected from this strain against the Minimum Information about a Biosynthetic Gene Cluster (MIBiG) database and 3365 BGCs predicted by antiSMASH analysis of publicly available complete Streptomyces genomes were generated through the BiG-SCAPE-CORASON platform to evaluate its biosynthetic novelty. Crude extract analysis using high-performance liquid chromatography connected to high resolution tandem mass spectrometry (HPLC-HRMS/MS) and dereplication through the Global Natural Product Social Molecular Networking (GNPS) online workflow resulted in the identification of cyclic dipeptides (2, 5-diketopiperazines, DKPs) in the extract, which are known to possess QSI activity. Our results highlight the potential of genome mining coupled with LC-HRMS/MS and in silico tools (GNPS) as a valid approach for the discovery of novel QSI lead compounds. This study also provides the biosynthetic diversity of BGCs and an assessment of the predicted chemical space yet to be discovered.
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Affiliation(s)
- Nabila Mohammed Ishaque
- Department of Biomedical Sciences, School of Biosciences and Technology, VIT University, Vellore 632014, India; (N.M.I.); (K.K.)
| | - Ilia Burgsdorf
- Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, Mt. Carmel, Haifa 31905, Israel; (I.B.); (L.S.)
| | - Jessie James Limlingan Malit
- Department of Ocean Science, Division of Life Science and Hong Kong, Branch of the Southern Marine Science and Engineering Guangdong Laboratory, The Hong Kong University of Science and Technology, Hong Kong, China;
| | - Subhasish Saha
- Laboratory of Algal Biotechnology-Centre Algatech, Institute of Microbiology of the Czech Academy of Sciences, Opatovickýmlýn, Novohradská 237, 37981 Třeboň, Czech Republic; (S.S.); (D.E.); (P.H.)
| | - Roberta Teta
- The Blue Chemistry Lab, Dipartimento di Farmacia, Università degli Studi di Napoli Federico II, Via D. Montesano 49, 80131 Napoli, Italy;
| | - Daniela Ewe
- Laboratory of Algal Biotechnology-Centre Algatech, Institute of Microbiology of the Czech Academy of Sciences, Opatovickýmlýn, Novohradská 237, 37981 Třeboň, Czech Republic; (S.S.); (D.E.); (P.H.)
| | - Krishnan Kannabiran
- Department of Biomedical Sciences, School of Biosciences and Technology, VIT University, Vellore 632014, India; (N.M.I.); (K.K.)
| | - Pavel Hrouzek
- Laboratory of Algal Biotechnology-Centre Algatech, Institute of Microbiology of the Czech Academy of Sciences, Opatovickýmlýn, Novohradská 237, 37981 Třeboň, Czech Republic; (S.S.); (D.E.); (P.H.)
| | - Laura Steindler
- Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, Mt. Carmel, Haifa 31905, Israel; (I.B.); (L.S.)
| | - Valeria Costantino
- The Blue Chemistry Lab, Dipartimento di Farmacia, Università degli Studi di Napoli Federico II, Via D. Montesano 49, 80131 Napoli, Italy;
| | - Kumar Saurav
- Department of Biomedical Sciences, School of Biosciences and Technology, VIT University, Vellore 632014, India; (N.M.I.); (K.K.)
- Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, Mt. Carmel, Haifa 31905, Israel; (I.B.); (L.S.)
- Laboratory of Algal Biotechnology-Centre Algatech, Institute of Microbiology of the Czech Academy of Sciences, Opatovickýmlýn, Novohradská 237, 37981 Třeboň, Czech Republic; (S.S.); (D.E.); (P.H.)
- The Blue Chemistry Lab, Dipartimento di Farmacia, Università degli Studi di Napoli Federico II, Via D. Montesano 49, 80131 Napoli, Italy;
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Mahan K, Martinmaki R, Larus I, Sikdar R, Dunitz J, Elias M. Effects of Signal Disruption Depends on the Substrate Preference of the Lactonase. Front Microbiol 2020; 10:3003. [PMID: 31993034 PMCID: PMC6971184 DOI: 10.3389/fmicb.2019.03003] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 12/12/2019] [Indexed: 12/19/2022] Open
Abstract
Many bacteria produce and use extracellular signaling molecules such as acyl homoserine lactones (AHLs) to communicate and coordinate behavior in a cell-density dependent manner, via a communication system called quorum sensing (QS). This system regulates behaviors including but not limited to virulence and biofilm formation. We focused on Pseudomonas aeruginosa, a human opportunistic pathogen that is involved in acute and chronic lung infections and which disproportionately affects people with cystic fibrosis. P. aeruginosa infections are becoming increasingly challenging to treat with the spread of antibiotic resistance. Therefore, QS disruption approaches, known as quorum quenching, are appealing due to their potential to control the virulence of resistant strains. Interestingly, P. aeruginosa is known to simultaneously utilize two main QS circuits, one based on C4-AHL, the other with 3-oxo-C12-AHL. Here, we evaluated the effects of signal disruption on 39 cystic fibrosis clinical isolates of P. aeruginosa, including drug resistant strains. We used two enzymes capable of degrading AHLs, known as lactonases, with distinct substrate preference: one degrading 3-oxo-C12-AHL, the other degrading both C4-AHL and 3-oxo-C12-AHL. Two lactonases were used to determine the effects of signal disruption on the clinical isolates, and to evaluate the importance of the QS circuits by measuring effects on virulence factors (elastase, protease, and pyocyanin) and biofilm formation. Signal disruption results in at least one of these factors being inhibited for most isolates (92%). Virulence factor activity or production were inhibited by up to 100% and biofilm was inhibited by an average of 2.3 fold. Remarkably, the treatments led to distinct inhibition profiles of the isolates; the treatment with the lactonase degrading both signaling molecules resulted in a higher fraction of inhibited isolates (77% vs. 67%), and the simultaneous inhibition of more virulence factors per strain (2 vs. 1.5). This finding suggests that the lactonase AHL preference is key to its inhibitory spectrum and is an essential parameter to improve quorum quenching strategies.
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Affiliation(s)
- Kathleen Mahan
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Medicine, University of Minnesota, Minneapolis, MN, United States
| | - Ryan Martinmaki
- Department of Biochemistry, Molecular Biology and Biophysics, Biotechnology Institute, University of Minnesota, Saint Paul, MN, United States
| | - Isabel Larus
- Department of Biochemistry, Molecular Biology and Biophysics, Biotechnology Institute, University of Minnesota, Saint Paul, MN, United States
| | - Rakesh Sikdar
- Department of Biochemistry, Molecular Biology and Biophysics, Biotechnology Institute, University of Minnesota, Saint Paul, MN, United States
| | - Jordan Dunitz
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Medicine, University of Minnesota, Minneapolis, MN, United States
- Department of Medicine, Minnesota Cystic Fibrosis Center and Adult CF Program, University of Minnesota, Minneapolis, MN, United States
| | - Mikael Elias
- Department of Biochemistry, Molecular Biology and Biophysics, Biotechnology Institute, University of Minnesota, Saint Paul, MN, United States
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O’Brien TJ, Welch M. A Continuous-Flow Model for in vitro Cultivation of Mixed Microbial Populations Associated With Cystic Fibrosis Airway Infections. Front Microbiol 2019; 10:2713. [PMID: 31824471 PMCID: PMC6883238 DOI: 10.3389/fmicb.2019.02713] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Accepted: 11/08/2019] [Indexed: 12/13/2022] Open
Abstract
The airways of people with cystic fibrosis (CF) provide a nutrient-rich environment which favours colonisation by a variety of bacteria and fungi. Although the dominant pathogen associated with CF airway infections is Pseudomonas aeruginosa, it is becoming increasingly clear that inter-species interactions between P. aeruginosa and other colonists in the airways may have a large impact on microbial physiology and virulence. However, there are currently no suitable experimental models that permit long-term co-culture of P. aeruginosa with other CF-associated pathogens. Here, we redress this problem by describing a "3R's-compliant" continuous-flow in vitro culture model which enables long-term co-culture of three representative CF-associated microbes: P. aeruginosa, Staphylococcus aureus and Candida albicans. Although these species rapidly out-compete one another when grown together or in pairs in batch culture, we show that in a continuously-fed setup, they can be maintained in a very stable, steady-state community. We use our system to show that even numerically (0.1%) minor species can have a major impact on intercellular signalling by P. aeruginosa. Importantly, we also show that co-culturing does not appear to influence species mutation rates, further reinforcing the notion that the system favours stability rather than divergence. The model is experimentally tractable and offers an inexpensive yet robust means of investigating inter-species interactions between CF pathogens.
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Affiliation(s)
| | - Martin Welch
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
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Deryabin D, Galadzhieva A, Kosyan D, Duskaev G. Plant-Derived Inhibitors of AHL-Mediated Quorum Sensing in Bacteria: Modes of Action. Int J Mol Sci 2019; 20:E5588. [PMID: 31717364 PMCID: PMC6888686 DOI: 10.3390/ijms20225588] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 11/02/2019] [Accepted: 11/06/2019] [Indexed: 12/15/2022] Open
Abstract
Numerous gram-negative phytopathogenic and zoopathogenic bacteria utilise acylated homoserine lactone (AHL) in communication systems, referred to as quorum sensing (QS), for induction of virulence factors and biofilm development. This phenomenon positions AHL-mediated QS as an attractive target for anti-infective therapy. This review focused on the most significant groups of plant-derived QS inhibitors and well-studied individual compounds for which in silico, in vitro and in vivo studies provide substantial knowledge about their modes of anti-QS activity. The current data about sulfur-containing compounds, monoterpenes and monoterpenoids, phenylpropanoids, benzoic acid derivatives, diarylheptanoids, coumarins, flavonoids and tannins were summarized; their plant sources, anti-QS effects and bioactivity mechanisms have also been summarized and discussed. Three variants of plant-derived molecules anti-QS strategies are proposed: (i) specific, via binding with LuxI-type AHL synthases and/or LuxR-type AHL receptor proteins, which have been shown for terpenes (carvacrol and l-carvone), phenylpropanoids (cinnamaldehyde and eugenol), flavonoid quercetin and ellagitannins; (ii) non-specific, by affecting the QS-related intracellular regulatory pathways by lowering regulatory small RNA expression (sulphur-containing compounds ajoene and iberin) or c-di-GMP metabolism reduction (coumarin); and (iii) indirect, via alteration of metabolic pathways involved in QS-dependent processes (vanillic acid and curcumin).
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Affiliation(s)
- Dmitry Deryabin
- Federal Scientific Center of Biological Systems and Agrotechnologies of RAS, Orenburg 460000, Russia; (A.G.); (D.K.); (G.D.)
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Liang X, Matthew S, Chen QY, Kwan JC, Paul VJ, Luesch H. Discovery and Total Synthesis of Doscadenamide A: A Quorum Sensing Signaling Molecule from a Marine Cyanobacterium. Org Lett 2019; 21:7274-7278. [PMID: 31414826 PMCID: PMC7325281 DOI: 10.1021/acs.orglett.9b02525] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Quorum sensing (QS) plays a critical role in the regulation of bacterial pathogenesis. Doscadenamide A (1a) was isolated from a marine cyanobacterium, its structure elucidated by NMR, and its activity linked to QS induction. The total synthesis of 1a was developed, and the absolute configuration confirmed through comparison of the isolated natural product with synthetic diastereomers. Our preliminary investigation indicated that 1a could activate QS signaling in a LasR-dependent manner.
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Affiliation(s)
- Xiao Liang
- Department of Medicinal Chemistry, University of Florida, Gainesville, Florida 32610, United States
- Center for Natural Products, Drug Discovery and Development (CNPD3), University of Florida, Gainesville, Florida 32610, United States
| | - Susan Matthew
- Department of Medicinal Chemistry, University of Florida, Gainesville, Florida 32610, United States
| | - Qi-Yin Chen
- Department of Medicinal Chemistry, University of Florida, Gainesville, Florida 32610, United States
- Center for Natural Products, Drug Discovery and Development (CNPD3), University of Florida, Gainesville, Florida 32610, United States
| | - Jason C. Kwan
- Department of Medicinal Chemistry, University of Florida, Gainesville, Florida 32610, United States
| | - Valerie J. Paul
- Smithsonian Marine Station, Fort Pierce, Florida 34949, United States
| | - Hendrik Luesch
- Department of Medicinal Chemistry, University of Florida, Gainesville, Florida 32610, United States
- Center for Natural Products, Drug Discovery and Development (CNPD3), University of Florida, Gainesville, Florida 32610, United States
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Interference with Pseudomonas aeruginosa Quorum Sensing and Virulence by the Mycobacterial Pseudomonas Quinolone Signal Dioxygenase AqdC in Combination with the N-Acylhomoserine Lactone Lactonase QsdA. Infect Immun 2019; 87:IAI.00278-19. [PMID: 31308081 DOI: 10.1128/iai.00278-19] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 06/26/2019] [Indexed: 11/20/2022] Open
Abstract
The nosocomial pathogen Pseudomonas aeruginosa regulates its virulence via a complex quorum sensing network, which, besides N-acylhomoserine lactones, includes the alkylquinolone signal molecules 2-heptyl-3-hydroxy-4(1H)-quinolone (Pseudomonas quinolone signal [PQS]) and 2-heptyl-4(1H)-quinolone (HHQ). Mycobacteroides abscessus subsp. abscessus, an emerging pathogen, is capable of degrading the PQS and also HHQ. Here, we show that although M. abscessus subsp. abscessus reduced PQS levels in coculture with P. aeruginosa PAO1, this did not suffice for quenching the production of the virulence factors pyocyanin, pyoverdine, and rhamnolipids. However, the levels of these virulence factors were reduced in cocultures of P. aeruginosa PAO1 with recombinant M. abscessus subsp. massiliense overexpressing the PQS dioxygenase gene aqdC of M. abscessus subsp. abscessus, corroborating the potential of AqdC as a quorum quenching enzyme. When added extracellularly to P. aeruginosa cultures, AqdC quenched alkylquinolone and pyocyanin production but induced an increase in elastase levels. When supplementing P. aeruginosa cultures with QsdA, an enzyme from Rhodococcus erythropolis which inactivates N-acylhomoserine lactone signals, rhamnolipid and elastase levels were quenched, but HHQ and pyocyanin synthesis was promoted. Thus, single quorum quenching enzymes, targeting individual circuits within a complex quorum sensing network, may also elicit undesirable regulatory effects. Supernatants of P. aeruginosa cultures grown in the presence of AqdC, QsdA, or both enzymes were less cytotoxic to human epithelial lung cells than supernatants of untreated cultures. Furthermore, the combination of both aqdC and qsdA in P. aeruginosa resulted in a decline of Caenorhabditis elegans mortality under P. aeruginosa exposure.
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Yu Z, Yu D, Mao Y, Zhang M, Ding M, Zhang J, Wu S, Qiu J, Yin J. Identification and characterization of a LuxI/R-type quorum sensing system in Pseudoalteromonas. Res Microbiol 2019; 170:243-255. [DOI: 10.1016/j.resmic.2019.07.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 07/04/2019] [Accepted: 07/09/2019] [Indexed: 12/30/2022]
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Degrassi G, Mortato V, Devescovi G, Hoshino R, Chatnaparat T, Kojic M, Carpentieri-Pipolo V, Zhao Y, Venturi V. Many plant pathogenic Pseudomonas savastanoi pv glycinea isolates possess an inactive quorum sensing ahlR gene via a point mutation. FEMS Microbiol Lett 2019; 366:fnz149. [PMID: 31271427 DOI: 10.1093/femsle/fnz149] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 07/03/2019] [Indexed: 01/14/2023] Open
Abstract
Many plant bacterial pathogens monitor their group behaviour and their population density via production of N-acyl homoserine lactone signals which regulate the expression of several genes via the LuxI/R homologs. This regulatory network, termed quorum sensing (QS), is present in the soybean bacterial pathogen Pseudomonas savastanoi pv glycinea (Psg). The sequenced genomes of two strains of Psg, race 4 and B076, contain an N-acyl homoserine lactone (AHL) based LuxI/R QS system named AhlI/R. While studying the QS system of Psg strains race 4 and B076 isolated in USA, LMG5066 in New Zealand and IBSBF355 in Brazil, we found that B076, LMG5066 and IBSBF355 possess a point mutation in the ahlR gene that causes a frameshift resulting in a truncated AhlR protein. Psg race 4 does not possess the mutation in ahlR and the QS system is functional. The same mutation in the ahlR gene was found to be also present in 9 of 19 Psg strains isolated from diseased soybean in Illinois. Phenotypic analysis of strains showed that swarming motility is repressed whereas phosphate solubilisation was activated by QS in Psg. Analysing the secretome, we also found that four proteins were under QS regulation.
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Affiliation(s)
- Giuliano Degrassi
- Industrial Biotechnology Group, IBioBA-ICGEB, Godoy Cruz 2390, Buenos Aires, Argentina
| | - Valentina Mortato
- Industrial Biotechnology Group, IBioBA-ICGEB, Godoy Cruz 2390, Buenos Aires, Argentina
| | - Giulia Devescovi
- Bacteriology Group, ICGEB, Padriciano 99, I-34149 Trieste, Italy
| | - Rodrigo Hoshino
- Agronomy Department, Londrina State University, Londrina 10.011, Parana, Brasil
| | - Tiyakhon Chatnaparat
- Department of Crop Sciences, 288 E R Madigan Laboratory, 1201 W. Gregory Dr., Urbana, IL 61801, USA
| | - Milan Kojic
- Institute of Molecular Genetics and Genetic Engineering (IMGGE), V. Stepe 444a, P.O. Box 23, 11010 Belgrade, Serbia
| | | | - Youfu Zhao
- Department of Crop Sciences, 288 E R Madigan Laboratory, 1201 W. Gregory Dr., Urbana, IL 61801, USA
| | - Vittorio Venturi
- Bacteriology Group, ICGEB, Padriciano 99, I-34149 Trieste, Italy
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Hansen MJ, Hille JI, Szymanski W, Driessen AJ, Feringa BL. Easily Accessible, Highly Potent, Photocontrolled Modulators of Bacterial Communication. Chem 2019. [DOI: 10.1016/j.chempr.2019.03.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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63
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Xu Z, Zhang H, Yu H, Dai Q, Xiong J, Sheng H, Qiu J, Jiang L, Peng J, He X, Xin R, Li D, Zhang K. Allicin inhibits Pseudomonas aeruginosa virulence by suppressing the rhl and pqs quorum-sensing systems. Can J Microbiol 2019; 65:563-574. [PMID: 31009577 DOI: 10.1139/cjm-2019-0055] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Pseudomonas aeruginosa is a virulent bacterium that secretes a variety of virulence factors that aid in establishing infections in individuals. Allicin, derived from garlic, has been shown to inhibit virulence factor production and biofilm formation in P. aeruginosa. However, the mechanisms underlying the allicin-mediated regulation of P. aeruginosa virulence remain unclear. In this study, we investigated the possible mechanisms underlying allicin-mediated virulence regulation in P. aeruginosa. The results showed that allicin attenuates the production of P. aeruginosa virulence-associated factors, such as elastase, pyocyanin, pyoverdine, and rhamnolipids, by inhibiting the rhl and pqs quorum-sensing systems. Further analysis revealed that the rhl and pqs systems play different roles during the allicin-mediated regulation process. Taken together, these results support the potential use of allicin as a therapeutic agent in controlling P. aeruginosa infection and associated mechanisms.
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Affiliation(s)
- Zhimin Xu
- Central Laboratory, Xinqiao Hospital, Army Medical University, Chongqing, China.,Central Laboratory, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Hong Zhang
- Central Laboratory, Xinqiao Hospital, Army Medical University, Chongqing, China.,Central Laboratory, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Hua Yu
- Central Laboratory, Xinqiao Hospital, Army Medical University, Chongqing, China.,Central Laboratory, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Qian Dai
- Central Laboratory, Xinqiao Hospital, Army Medical University, Chongqing, China.,Central Laboratory, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Junzhi Xiong
- Central Laboratory, Xinqiao Hospital, Army Medical University, Chongqing, China.,Central Laboratory, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Halei Sheng
- Central Laboratory, Xinqiao Hospital, Army Medical University, Chongqing, China.,Central Laboratory, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Jing Qiu
- Central Laboratory, Xinqiao Hospital, Army Medical University, Chongqing, China.,Central Laboratory, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Lu Jiang
- Central Laboratory, Xinqiao Hospital, Army Medical University, Chongqing, China.,Central Laboratory, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Jin Peng
- Central Laboratory, Xinqiao Hospital, Army Medical University, Chongqing, China.,Central Laboratory, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Xiaomei He
- Central Laboratory, Xinqiao Hospital, Army Medical University, Chongqing, China.,Central Laboratory, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Rong Xin
- Central Laboratory, Xinqiao Hospital, Army Medical University, Chongqing, China.,Central Laboratory, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Defeng Li
- Central Laboratory, Xinqiao Hospital, Army Medical University, Chongqing, China.,Central Laboratory, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Kebin Zhang
- Central Laboratory, Xinqiao Hospital, Army Medical University, Chongqing, China.,Central Laboratory, Xinqiao Hospital, Army Medical University, Chongqing, China
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64
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Al-Yousef HM, Sheikh IA. β-Sitosterol derived compound from onion husks non-polar fraction reduces quorum sensing controlled virulence and biofilm production. Saudi Pharm J 2019; 27:664-672. [PMID: 31297021 PMCID: PMC6598451 DOI: 10.1016/j.jsps.2019.04.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2018] [Accepted: 04/01/2019] [Indexed: 11/06/2022] Open
Abstract
Quorum sensing is an important regulatory factor of P. aeruginosa virulence induction such as BF, motility, formations of proteases, pyocyanin, and some toxins. The aim of the current study is to detect the effect of the pet.ether extract from onion husk and compound drive from it on quorum sensing and virulence formations of P. aeruginosa. Quorum sensing inhibiting effect of the pet.ether extract of onion husk and a compound drive from it, was evaluated by C. violaceum reporter using dilution method as well as an antioxidant by using DPPH. The efficacious of: Quorum sensing inhibiting on pet.ether fraction and compound derived from it, were investigated for their activities toward biofilm and pyocyanin synthesis as well as motility from P. aeruginosa. The pet.ether fraction and compound derived from it of onion husk exhibited potent antimicrobial, antioxidant and Quorum sensing inhibiting effects. The pet.ether fraction and compound derived from it possesses significant reduction on pyocyanin and biofilm induction of P. aeruginosa. Moreover, they significantly inhibited swimming motilities of P. aeruginosa. For the first time, our study showed the medical importance of Allium cepa L. as antimicrobial, antioxidant as well as Quorum sensing inhibiting and virulence suppressors of P. aeruginosa. Thus, these might emphasized on Allium cepa L as a natural source for attenuating toxins of the Pseudomonas.
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Affiliation(s)
- Hanan M Al-Yousef
- Department of Pharmacognosy, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Ishfaq Ahmad Sheikh
- King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia
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65
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Significantly improved production of Welan gum by Sphingomonas sp. WG through a novel quorum-sensing-interfering dipeptide cyclo(L-Pro-L-Phe). Int J Biol Macromol 2019; 126:118-122. [DOI: 10.1016/j.ijbiomac.2018.12.189] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 12/21/2018] [Accepted: 12/21/2018] [Indexed: 12/16/2022]
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66
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Maddela NR, Sheng B, Yuan S, Zhou Z, Villamar-Torres R, Meng F. Roles of quorum sensing in biological wastewater treatment: A critical review. CHEMOSPHERE 2019; 221:616-629. [PMID: 30665091 DOI: 10.1016/j.chemosphere.2019.01.064] [Citation(s) in RCA: 94] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 12/23/2018] [Accepted: 01/09/2019] [Indexed: 06/09/2023]
Abstract
Quorum sensing (QS) and quorum quenching (QQ) are increasingly reported in biological wastewater treatment processes because of their inherent roles in biofilm development, bacterial aggregation, granulation, colonization, and biotransformation of pollutants. As such, the fundamentals and ubiquitous nature of QS bacteria are critical for fully understanding the process of the wastewater treatment system. In this article, the details of QS-based strategies related to community behaviors and phenotypes in wastewater treatment systems were reviewed. The molecular aspects and coexistence of QS and QQ bacteria were also mentioned, which provide evidence that future wastewater treatment will indispensably rely on QS-based strategies. In addition, recent attempts focusing on the use of QQ for biofilm or biofouling control were also summarized. Nevertheless, there are still several challenges and knowledge gaps that warrant future targeted research on the ecological niche, abundance, and community of QS- and QQ-bacteria in environmental settings or engineered systems.
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Affiliation(s)
- Naga Raju Maddela
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, PR China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Guangzhou 510275, PR China; Facultad de Ciencias de la Salud, Universidad Técnica de Manabí, Portoviejo 130105, Ecuador
| | - Binbin Sheng
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, PR China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Guangzhou 510275, PR China
| | - Shasha Yuan
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, PR China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Guangzhou 510275, PR China
| | - Zhongbo Zhou
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, PR China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Guangzhou 510275, PR China
| | - Ronald Villamar-Torres
- Université de Montpellier, CIRAD, INRA, Montpellier SupAgro, Montpellier 34090, France; Facultad de Ingeniería Agronómica, Universidad Técnica de Manabí, Campus Experimental "La Teodomira", Santa Ana 131301, Ecuador
| | - Fangang Meng
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, PR China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Guangzhou 510275, PR China.
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67
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Aslanli A, Lyagin I, Efremenko E. Novel approach to quorum quenching: rational design of antibacterials in combination with hexahistidine-tagged organophosphorus hydrolase. Biol Chem 2019; 399:869-879. [PMID: 29870390 DOI: 10.1515/hsz-2018-0162] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Accepted: 05/02/2018] [Indexed: 11/15/2022]
Abstract
N-acyl homoserine lactones (AHLs) are quorum sensing (QS) signal molecules used by most Gram-negative pathogenic bacteria. In this article the lactonase activity of the preparations based on hexahistidine-tagged organophosphorus hydrolase (His6-OPH) towards AHLs was studied. Initially, three of the most interesting β-lactam antibiotics were selected from seven that were trialed during molecular docking to His6-OPH. Combinations of antibiotics (meropenem, imipenem, ceftriaxone) and His6-OPH taken in the native form or in the form of non-covalent enzyme-polyelectrolyte complexes (EPCs) with poly(glutamic acid) or poly(aspartic acid) were obtained and investigated. The lactonase activity of the preparations was investigated under different physical-chemical conditions in the hydrolysis of AHLs [N-butyryl-D,L-homoserine lactone, N-(3-oxooctanoyl)-D,L-homoserine lactone, N-(3-oxododecanoyl)-L-homoserine lactone]. An increased efficiency of catalytic action and stability of the lactonase activity of His6-OPH was shown for its complexes with antibiotics and was confirmed in trials with bacterial strains. The broadening of the catalytic action of the enzyme against AHLs was revealed in the presence of the meropenem. Results of molecular docking of AHLs to the surface of the His6-OPH dimer in the presence of antibiotics allowed proposing the mechanism of such interference based on a steric repulsion of the carbon chain of hydrolyzed AHLs by the antibiotics bounded to the enzyme surface.
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Affiliation(s)
- Aysel Aslanli
- Faculty of Chemistry, Lomonosov Moscow State University, Moscow 119991, Russia
| | - Ilya Lyagin
- Faculty of Chemistry, Lomonosov Moscow State University, Moscow 119991, Russia
| | - Elena Efremenko
- Faculty of Chemistry, Lomonosov Moscow State University, Moscow 119991, Russia
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68
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Monson RE, Apagyi K, Bowden SD, Simpson N, Williamson NR, Cubitt MF, Harris S, Toth IK, Salmond GPC. The rsmS (ybaM) mutation causes bypass suppression of the RsmAB post-transcriptional virulence regulation system in enterobacterial phytopathogens. Sci Rep 2019; 9:4525. [PMID: 30872786 PMCID: PMC6418279 DOI: 10.1038/s41598-019-40970-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 02/22/2019] [Indexed: 11/09/2022] Open
Abstract
Plant cell wall degrading enzymes (PCWDEs) are the primary virulence determinants of soft rotting bacteria such as the potato pathogen, Pectobacterium atrosepticum. The regulation of secondary metabolite (Rsm) system controls production of PCWDEs in response to changing nutrient conditions. This work identified a new suppressor of an rsmB mutation - ECA1172 or rsmS (rsmB suppressor). Mutants defective in rsmB (encoding a small regulatory RNA), show reduced elaboration of the quorum sensing molecule (N-3-oxohexanoyl-homoserine lactone; OHHL) and PCWDEs. However, OHHL and PCWDE production were partially restored in an rsmB, rsmS double mutant. Single rsmS mutants, overproduced PCWDEs and OHHL relative to wild type P. atrosepticum and exhibited hypervirulence in potato. RsmS overproduction also resulted in increased PCWDEs and OHHL. Homology searches revealed rsmS conservation across pathogens such as Escherichia coli (ybaM), Dickeya solani, Klebsiella pneumoniae and Shigella flexneri. An rsmS mutant of Pectobacterium carotovorum ATCC39048 showed bypass of rsmB-dependent repression of PCWDEs and OHHL production. P. carotovorum ATCC39048 produces the β-lactam antibiotic, 1-carbapen-2-em-3-carboxylic acid (a carbapenem). Production of the antibiotic was repressed in an rsmB mutant but partially restored in an rsmB, rsmS double mutant. This work highlights the importance of RsmS, as a conserved pleiotropic regulator of virulence and antibiotic biosynthesis.
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Affiliation(s)
- Rita E Monson
- Department of Biochemistry, Hopkins Building, Tennis Court Road, University of Cambridge, Cambridge, CB2 1QW, UK
| | - Katinka Apagyi
- Department of Biochemistry, Hopkins Building, Tennis Court Road, University of Cambridge, Cambridge, CB2 1QW, UK
- Faculty of Medicine, School of Public Health, Imperial College, London, St Mary's Campus, Norfolk Place, W2 1PG, UK
| | - Steven D Bowden
- Department of Biochemistry, Hopkins Building, Tennis Court Road, University of Cambridge, Cambridge, CB2 1QW, UK
- Department of Food Science and Nutrition, University of Minnesota-Twin Cities, St. Paul, Minnesota, USA
| | - Natalie Simpson
- Department of Biochemistry, Hopkins Building, Tennis Court Road, University of Cambridge, Cambridge, CB2 1QW, UK
| | - Neil R Williamson
- Department of Biochemistry, Hopkins Building, Tennis Court Road, University of Cambridge, Cambridge, CB2 1QW, UK
| | - Marion F Cubitt
- Department of Biochemistry, Hopkins Building, Tennis Court Road, University of Cambridge, Cambridge, CB2 1QW, UK
| | - Steve Harris
- Department of Biochemistry, Hopkins Building, Tennis Court Road, University of Cambridge, Cambridge, CB2 1QW, UK
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, LE11 3TU, UK
| | - Ian K Toth
- Cell and Molecular Sciences, James Hutton Institute, Invergowrie, Dundee, DD2 5DA, UK
| | - George P C Salmond
- Department of Biochemistry, Hopkins Building, Tennis Court Road, University of Cambridge, Cambridge, CB2 1QW, UK.
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69
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Srisanga K, Suthapot P, Permsirivisarn P, Govitrapong P, Tungpradabkul S, Wongtrakoongate P. Polyphosphate kinase 1 of Burkholderia pseudomallei controls quorum sensing, RpoS and host cell invasion. J Proteomics 2019; 194:14-24. [DOI: 10.1016/j.jprot.2018.12.024] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Revised: 12/16/2018] [Accepted: 12/25/2018] [Indexed: 12/18/2022]
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70
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Draft Genome Sequence of the Marine Bacterium
Alteromonas
sp. Strain KS69. Microbiol Resour Announc 2019; 8:MRA00022-19. [PMID: 30714027 PMCID: PMC6357633 DOI: 10.1128/mra.00022-19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Accepted: 01/10/2019] [Indexed: 11/22/2022] Open
Abstract
Alteromonas spp. are Gram-negative, aerobic, marine bacteria. Here, we report the draft genome sequence of Alteromonas sp. strain KS69, isolated from Narragansett Bay deep water samples. Unpublished preliminary data suggest that KS69 reduces expression of the 3-oxo-C12-HSL-dependent, virulence-associated gene lasB of Pseudomonas aeruginosa PAO1, suggesting that it produces a quorum sensing inhibitor. Alteromonas spp. are Gram-negative, aerobic, marine bacteria. Here, we report the draft genome sequence of Alteromonas sp. strain KS69, isolated from Narragansett Bay deep water samples. Unpublished preliminary data suggest that KS69 reduces expression of the 3-oxo-C12-HSL-dependent, virulence-associated gene lasB of Pseudomonas aeruginosa PAO1, suggesting that it produces a quorum sensing inhibitor.
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71
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Krzyżanowska DM, Maciąg T, Ossowicki A, Rajewska M, Kaczyński Z, Czerwicka M, Rąbalski Ł, Czaplewska P, Jafra S. Ochrobactrum quorumnocens sp. nov., a quorum quenching bacterium from the potato rhizosphere, and comparative genome analysis with related type strains. PLoS One 2019; 14:e0210874. [PMID: 30668584 PMCID: PMC6342446 DOI: 10.1371/journal.pone.0210874] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 01/03/2019] [Indexed: 01/09/2023] Open
Abstract
Ochrobactrum spp. are ubiquitous bacteria attracting growing attention as important members of microbiomes of plants and nematodes and as a source of enzymes for biotechnology. Strain Ochrobactrum sp. A44T was isolated from the rhizosphere of a field-grown potato in Gelderland, the Netherlands. The strain can interfere with quorum sensing (QS) of Gram-negative bacteria through inactivation of N-acyl homoserine lactones (AHLs) and protect plant tissue against soft rot pathogens, the virulence of which is governed by QS. Phylogenetic analysis based on 16S rRNA gene alone and concatenation of 16S rRNA gene and MLSA genes (groEL and gyrB) revealed that the closest relatives of A44T are O. grignonense OgA9aT, O. thiophenivorans DSM 7216T, O. pseudogrignonense CCUG 30717T, O. pituitosum CCUG 50899T, and O. rhizosphaerae PR17T. Genomes of all six type strains were sequenced, significantly expanding the possibility of genome-based analyses in Ochrobactrum spp. Average nucleotide identity (ANIb) and genome-to-genome distance (GGDC) values for A44T and the related strains were below the single species thresholds (95% and 70%, respectively), with the highest scores obtained for O. pituitosum CCUG 50899T (87.31%; 35.6%), O. rhizosphaerae PR17T (86.80%; 34.3%), and O. grignonense OgA9aT (86.30%; 33.6%). Distinction of A44T from the related type strains was supported by chemotaxonomic and biochemical analyses. Comparative genomics revealed that the core genome for the newly sequenced strains comprises 2731 genes, constituting 50–66% of each individual genome. Through phenotype-to-genotype study, we found that the non-motile strain O. thiophenivorans DSM 7216T lacks a cluster of genes related to flagella formation. Moreover, we explored the genetic background of distinct urease activity among the strains. Here, we propose to establish a novel species Ochrobactrum quorumnocens, with A44T as the type strain (= LMG 30544T = PCM 2957T).
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Affiliation(s)
- Dorota M Krzyżanowska
- Laboratory of Biological Plant Protection, Intercollegiate Faculty of Biotechnology of University of Gdansk and Medical University of Gdansk, University of Gdansk, Gdansk, Poland
| | - Tomasz Maciąg
- Laboratory of Biological Plant Protection, Intercollegiate Faculty of Biotechnology of University of Gdansk and Medical University of Gdansk, University of Gdansk, Gdansk, Poland
| | - Adam Ossowicki
- Laboratory of Biological Plant Protection, Intercollegiate Faculty of Biotechnology of University of Gdansk and Medical University of Gdansk, University of Gdansk, Gdansk, Poland
| | - Magdalena Rajewska
- Laboratory of Biological Plant Protection, Intercollegiate Faculty of Biotechnology of University of Gdansk and Medical University of Gdansk, University of Gdansk, Gdansk, Poland
| | - Zbigniew Kaczyński
- Laboratory of Structural Biochemistry, Faculty of Chemistry, University of Gdansk, Gdansk, Poland
| | - Małgorzata Czerwicka
- Laboratory of Structural Biochemistry, Faculty of Chemistry, University of Gdansk, Gdansk, Poland
| | - Łukasz Rąbalski
- Laboratory of Recombinant Vaccines, Intercollegiate Faculty of Biotechnology of University of Gdansk and Medical University of Gdansk, University of Gdansk, Gdansk, Poland
| | - Paulina Czaplewska
- Laboratory of Mass Spectrometry, Intercollegiate Faculty of Biotechnology of University of Gdansk and Medical University of Gdansk, University of Gdansk, Gdansk, Poland
| | - Sylwia Jafra
- Laboratory of Biological Plant Protection, Intercollegiate Faculty of Biotechnology of University of Gdansk and Medical University of Gdansk, University of Gdansk, Gdansk, Poland
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72
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The Probiotic Bacterium Phaeobacter inhibens Downregulates Virulence Factor Transcription in the Shellfish Pathogen Vibrio coralliilyticus by N-Acyl Homoserine Lactone Production. Appl Environ Microbiol 2019; 85:AEM.01545-18. [PMID: 30389771 DOI: 10.1128/aem.01545-18] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2018] [Accepted: 10/30/2018] [Indexed: 01/25/2023] Open
Abstract
Phaeobacter inhibens S4Sm acts as a probiotic bacterium against the oyster pathogen Vibrio coralliilyticus Here, we report that P. inhibens S4Sm secretes three molecules that downregulate the transcription of major virulence factors, metalloprotease genes, in V. coralliilyticus cultures. The effects of the S4Sm culture supernatant on the transcription of three genes involved in protease activity, namely, vcpA, vcpB, and vcpR (encoding metalloproteases A and B and their transcriptional regulator, respectively), were examined by reverse transcriptase quantitative PCR (qRT-PCR). The expression of vcpB and vcpR were reduced to 36% and 6.6%, respectively, compared to that in an untreated control. We constructed a V. coralliilyticus green fluorescent protein (GFP) reporter strain to detect the activity of inhibitory compounds. Using a bioassay-guided approach, the molecules responsible for V. coralliilyticus protease inhibition activity were isolated from S4Sm supernatant and identified as three N-acyl homoserine lactones (AHLs). The three AHLs are N-(3-hydroxydecanoyl)-l-homoserine lactone, N-(dodecanoyl-2,5-diene)-l-homoserine lactone, and N-(3-hydroxytetradecanoyl-7-ene)-l-homoserine lactone, and their half maximal inhibitory concentrations (IC50s) against V. coralliilyticus protease activity were 0.26 μM, 3.7 μM, and 2.9 μM, respectively. Our qRT-PCR data demonstrated that exposures to the individual AHLs reduced the transcription of vcpR and vcpB Combinations of the three AHLs (any two or all three AHLs) on V. coralliilyticus produced additive effects on protease inhibition activity. These AHL compounds may contribute to the host protective effects of S4Sm by disrupting the quorum sensing pathway that activates protease transcription of V. coralliilyticus IMPORTANCE Probiotics represent a promising alternative strategy to control infection and disease caused by marine pathogens of aquaculturally important species. Generally, the beneficial effects of probiotics include improved water quality, control of pathogenic bacteria and their virulence, stimulation of the immune system, and improved animal growth. Previously, we isolated a probiotic bacterium, Phaeobacter inhibens S4Sm, which protects oyster larvae from Vibrio coralliilyticus RE22Sm infection. We also demonstrated that both antibiotic secretion and biofilm formation play important roles in S4Sm probiotic activity. Here, we report that P. inhibens S4Sm, an alphaproteobacterium and member of the Roseobacter clade, also secretes secondary metabolites that hijack the quorum sensing ability of V. coralliilyticus RE22Sm, suppressing virulence gene expression. This finding demonstrates that probiotic bacteria can exert their host protection by using a multipronged array of behaviors that limit the ability of pathogens to become established and cause infection.
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73
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Franco AG, Cadavid LF, Arévalo-Ferro C. Biofilms and Extracts from Bacteria Producing " Quorum Sensing" Signaling Molecules Promote Chemotaxis and Settlement Behaviors in Hydractinia symbiolongicarpus (Cnidaria: Hydrozoa) Larvae. ACTA BIOLÓGICA COLOMBIANA 2019. [DOI: 10.15446/abc.v24n1.73642] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Many sessile marine invertebrates have life cycles involving the development of larvae that settle on specific substrates to initiate metamorphosis to juvenile forms. Although is recognized that bacterial biofilms play a role in this process, the responsible chemical cues are beginning to be investigated. Here, we tested the role of substrate-specific bacteria biofilms and their Quorum Sensing Signaling Molecule (QSSM) extracts on chemotaxis and settlement of larvae from Hydractinia symbiolongicarpus, a hydroid that grows on gastropod shells occupied by hermit crabs. We isolated and taxonomically identified by 16S rDNA sequencing, 14 bacterial strains from shells having H. symbiolongicarpus. Three isolates, Shigella flexneri, Microbacterium liquefaciens, and Kocuria erythromyxa, were identified to produce QSSMs using biosensors detecting N-acyl-L-homoserine lactones. Multispecies biofilms and QSSM extracts from these bacteria showed a positive chemotactic effect on H. symbiolongicarpus larvae, a phenomenon not observed with mutant strains of E. coli and Chromobacterium violaceum that are unable to produce QSSMs. These biofilms and QSSMs extracts induced high rates of larval attachment, although only 1 % of the attached larvae metamorphosed to primary polyps, in contrast to 99 % of larvae incubated with CsCl, an artificial inductor of attachment and metamorphosis. These observations suggest that bacterial QSSMs participate in H. symbiolongicarpus substrate selection by inducing larval chemotaxis and attachment. Furthermore, they support the notion that settlement in cnidarians is decoupled into two processes, attachment to the substrate and metamorphosis to a primary polyp, where QSSMs likely participate in the former but not in the latter.
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74
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Abstract
Bacterial cells use the quorum sensing system to communicate with each other. The gram-negative species very often use N-acyl homoserine lactones for this purpose. One of the easiest ways to detect these molecules is the use of particular reporter strains, which possess different kinds of reporter genes under the control of AHL-responsive promoters. Here we present some of the possibilities available today, even for not specialized researchers.
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Affiliation(s)
- Elke Stein
- Institute for Phytopathology, IFZ, Justus Liebig University Giessen, Gießen, Germany
| | - Adam Schikora
- Julius Kühn-Institut, Federal Research Centre for Cultivated Plants (JKI), Institute for Epidemiology and Pathogen Diagnostics, Braunschweig, Germany.
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75
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Fernández M, Corral-Lugo A, Krell T. The plant compound rosmarinic acid induces a broad quorum sensing response in Pseudomonas aeruginosa PAO1. Environ Microbiol 2018; 20:4230-4244. [PMID: 30051572 DOI: 10.1111/1462-2920.14301] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Accepted: 05/28/2018] [Indexed: 02/05/2023]
Abstract
The interference of plant compounds with bacterial quorum sensing (QS) is a major mechanism through which plants and bacteria communicate. However, little is known about the modes of action and effects on signal integrity during this type of communication. We have recently shown that the plant compound rosmarinic acid (RA) specifically binds to the Pseudomonas aeruginosa RhlR QS receptor. To determine the effect of RA on expression patterns, we carried out global RNA-seq analysis. The results show that RA induces the expression of 128 genes, amongst which many virulence factor genes. RA triggers a broad QS response because 88% of the induced genes are known to be controlled by QS, and because RA stimulated genes were found to be involved in all four QS signalling systems within P. aeruginosa. This finding was confirmed through the analysis of transcriptional fusions transferred to wt and a rhlI/lasI double mutant. RA did not induce gene expression in the rhlI/lasI/rhlR triple mutant indicating that the effects observed are due to the RA-RhlR interaction. Furthermore, RA induced seven sRNAs that were all encoded in regions close to QS and/or RA induced genes. This work significantly enhances our understanding of plant bacteria interaction.
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Affiliation(s)
- Matilde Fernández
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - Andrés Corral-Lugo
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain
- Institut de Biologie Intégrative de la Cellule (I2BC), CNRS, Gif-Sur-Yvette, France
| | - Tino Krell
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain
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Alcalde-Rico M, Olivares-Pacheco J, Alvarez-Ortega C, Cámara M, Martínez JL. Role of the Multidrug Resistance Efflux Pump MexCD-OprJ in the Pseudomonas aeruginosa Quorum Sensing Response. Front Microbiol 2018; 9:2752. [PMID: 30532741 PMCID: PMC6266676 DOI: 10.3389/fmicb.2018.02752] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 10/26/2018] [Indexed: 11/15/2022] Open
Abstract
Multidrug efflux pumps constitute a category of antibiotic resistance determinants that are a part of the core bacterial genomes. Given their conservation, it is conceivable that they present functions beyond the extrusion of antibiotics currently used for therapy. Pseudomonas aeruginosa stands as a relevant respiratory pathogen, with a high prevalence at hospitals and in cystic fibrosis patients. Part of its success relies on its low susceptibility to antibiotics and on the production of virulence factors, whose expression is regulated in several cases by quorum sensing (QS). We found that overexpression of the MexCD-OprJ multidrug efflux pump shuts down the P. aeruginosa QS response. Our results support that MexCD-OprJ extrudes kynurenine, a precursor of the alkyl-quinolone signal (AQS) molecules. Anthranilate and octanoate, also AQS precursors, do not seem to be extruded by MexCD-OprJ. Kynurenine extrusion is not sufficient to reduce the QS response in a mutant overexpressing this efflux pump. Impaired QS response is mainly due to the extrusion of 4-hydroxy-2-heptylquinoline (HHQ), the precursor of the Pseudomonas Quinolone Signal (PQS), leading to low PQS intracellular levels and reduced production of QS signal molecules. As the consequence, the expression of QS-regulated genes is impaired and the production of QS-regulated virulence factors strongly decreases in a MexCD-OprN P. aeruginosa overexpressing mutant. Previous work showed that MexEF-OprJ, another P. aeruginosa efflux pump, is also able of extruding kynurenine and HHQ. However, opposite to our findings, the QS defect in a MexEF-OprN overproducer is due to kynurenine extrusion. These results indicate that, although efflux pumps can share some substrates, the affinity for each of them can be different. Although the QS response is triggered by population density, information on additional elements able of modulating such response is still scarce. This is particularly important in the case of P. aeruginosa lung chronic infections, a situation in which QS-defective mutants are accumulated. If MexCD-OprJ overexpression alleviates the cost associated to triggering the QS response when un-needed, it could be possible that MexCD-OprJ antibiotic resistant overproducer strains might be selected even in the absence of antibiotic selective pressure, acting as antibiotic resistant cheaters in heterogeneous P. aeruginosa populations.
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Affiliation(s)
- Manuel Alcalde-Rico
- Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Jorge Olivares-Pacheco
- Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Carolina Alvarez-Ortega
- Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Miguel Cámara
- Centre for Biomolecular Sciences, School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - José Luis Martínez
- Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Madrid, Spain
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77
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Martins ML, Pinto UM, Riedel K, Vanetti MCD. Quorum Sensing and Spoilage Potential of Psychrotrophic Enterobacteriaceae Isolated from Milk. BIOMED RESEARCH INTERNATIONAL 2018; 2018:2723157. [PMID: 30426005 PMCID: PMC6217898 DOI: 10.1155/2018/2723157] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 09/25/2018] [Accepted: 10/02/2018] [Indexed: 12/03/2022]
Abstract
The 16S rDNA of six psychrotrophic Enterobacteriaceae isolated from cold raw milk were sequenced and the isolate 039 was identified as Pantoea sp., isolates 059, 068, and 071 were identified as Hafnia alvei, 067 was identified as Enterobacter sp., and 099 was identified as Aeromonas hydrophila. They presented different spoilage potentials in milk with A. hydrophila 099 being the most deteriorative. Only Pantoea sp. 039 was not able to induce the quorum sensing monitor strains of acyl homoserine lactones (AHLs). The halI gene, which encodes the AHL synthase in H. alvei, was identified in the isolates 059, 067, 068, and 071. After initial sequencing characterization and cloning, this gene showed its function by the heterologous synthesis of N-hexanoyl-DL-homoserine lactone and N-3-oxohexanoyl-L-homoserine lactone in Escherichia coli. In addition to producing AHLs, A. hydrophila 099 produced AI-2 in higher level than the assay's positive control Vibrio harveyi BB120. Therefore, Enterobacteriaceae strains isolated from cooled raw milk produce a rich array of signaling molecules that may influence bacterial traits in the milk environment.
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Affiliation(s)
- Maurilio Lopes Martins
- Department of Food Science and Technology, Federal Institute of Southeast of Minas Gerais, 36180-000 Rio Pomba, MG, Brazil
| | - Uelinton Manoel Pinto
- Food Research Center, Department of Food and Experimental Nutrition, Faculty of Pharmaceutical Sciences, University of São Paulo, 05508-000 São Paulo, SP, Brazil
| | - Katharina Riedel
- Institute of Microbiology, Ernst-Moritz-Arndt University of Greifswald, 17489, Germany
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78
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Zhou Y, Memelink J, Linthorst HJM. An E. coli biosensor for screening of cDNA libraries for isochorismate pyruvate lyase-encoding cDNAs. Mol Genet Genomics 2018; 293:1181-1190. [PMID: 29796759 PMCID: PMC6153503 DOI: 10.1007/s00438-018-1450-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Accepted: 05/17/2018] [Indexed: 01/24/2023]
Abstract
Salicylic acid (SA) is an essential hormone for development and induced defense against biotrophic pathogens in plants. The formation of SA mainly derives from chorismate via demonstrated isochorismate synthase (ICS) and presumed isochorismate pyruvate lyase (IPL)-mediated steps in Arabidopsis thaliana, but so far no plant enzyme displaying IPL activity has been identified. Here, we developed an E. coli SA biosensor to screen for IPL activity based on the SalR regulator/salA promoter combination from Acinetobacter sp ADP1, to control the expression of the reporter luxCDABE. The biosensor was responsive to micromolar concentrations of exogenous SA, and to endogenous SA produced after transformation with a plasmid permitting IPTG-inducible expression of bacterial IPL in this biosensor strain. After screening a cDNA library constructed from turnip crinkle virus (TCV)-infected Arabidopsis ecotype Di-17, we identified an enzyme, PRXR1, as a putative IPL that converts isochorismate into SA. Our results provide a new experimental approach to identify IPL and new insights into the SA biosynthesis pathway in Arabidopsis.
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Affiliation(s)
- Yingjie Zhou
- Institute of Biology, Leiden University, P.O. Box 9505, 2300 RA, Leiden, The Netherlands
| | - Johan Memelink
- Institute of Biology, Leiden University, P.O. Box 9505, 2300 RA, Leiden, The Netherlands
| | - Huub J M Linthorst
- Institute of Biology, Leiden University, P.O. Box 9505, 2300 RA, Leiden, The Netherlands.
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79
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Wynn D, Raut N, Joel S, Pasini P, Deo SK, Daunert S. Detection of bacterial contamination in food matrices by integration of quorum sensing in a paper-strip test. Analyst 2018; 143:4774-4782. [PMID: 30215084 DOI: 10.1039/c8an00878g] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
There are an estimated 48 million cases of foodborne illness in the United States every year. In general, these illnesses are the result of unintentional contamination and improper food handling. Because bacterial contamination plays a major role in food spoilage and, hence, in foodborne illnesses, it is important to design easy, portable methods to detect bacteria in food. Quorum sensing (QS) enables bacteria to communicate with one another and by doing so they can modulate their behavior in a cell-density dependent manner. In bacteria, quorum sensing molecules (QSMs) are known to control several factors such as virulence factor production, antibiotic production, biofilm formation, and gene regulation. Herein, we demonstrate the applicability of whole cell biosensing systems for the early identification of food contamination via detection of QSMs. Additionally, we have developed a portable system for detection of bacterial contamination using microdots of immobilized whole cell-based biosensors on paper that boast nanomolar level detection of QSMs in two different food matrices, namely beef and milk. Limits of detection ranged from 1 × 10-7 M to 1 × 10-9 M with relative standard deviations (RSDs) of 1-16%. This rapid, easy, and portable test could be a useful tool for use in the field and during all stages of food manipulation, i.e., from farms to distribution, storage, sales, and preparation prior to consumption, to ensure that food is free of bacterial contamination.
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Affiliation(s)
- Daniel Wynn
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, Florida 33136, USA.
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80
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Wang Y, Gao L, Rao X, Wang J, Yu H, Jiang J, Zhou W, Wang J, Xiao Y, Li M, Zhang Y, Zhang K, Shen L, Hua Z. Characterization of lasR-deficient clinical isolates of Pseudomonas aeruginosa. Sci Rep 2018; 8:13344. [PMID: 30190495 PMCID: PMC6127196 DOI: 10.1038/s41598-018-30813-y] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 08/06/2018] [Indexed: 01/24/2023] Open
Abstract
Pseudomonas aeruginosa is a prevalent opportunistic pathogen that causes fatal infections in immunocompromised individuals. Quorum sensing (QS) is a cell-to-cell communication process that controls virulence gene expression and biofilm formation in P. aeruginosa. Here, the QS systems and the relevant virulence traits in clinical P. aeruginosa isolates were characterized. Eleven out of the ninety-four P. aeruginosa isolates exhibited a biofilm-deficient phenotype. Two biofilm-deficient isolates, one from blood and the one from pleural effusion, appeared to carry a same mutation in lasR. These two isolates differed in the ability to produce QS-regulated virulence factors, but contained the same functionally deficient LasR with the truncated C-terminal domains and belonged to the same multilocus sequence type (ST227). Chromosomal lasR complementation in these lasR mutants verified that lasR inactivation was the sole cause of las deficiency. LasR was not absolutely required for rhl signal in these lasR mutants, suggesting the presence of lasR-independent QS systems. We provided evidence that the virulence gene expression are not regulated in the same manner in these isolates. These results support the hypothesis that conventional QS hierarchy can be smashed by naturally occurring lasR mutation in clinical P. aeruginosa isolates and that complex QS hierarchy may play a role in maintaining infection of this opportunistic pathogen.
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Affiliation(s)
- Yao Wang
- Department of Neonatology, Children's Hospital of Chongqing Medical University, Ministry of Education Key Laboratory of Child Development and Disorders, China International Science and Technology Cooperation base of Child development and Critical Disorders, Chongqing Key Laboratory of Child Infection and Immunity, Chongqing, 40014, China
| | - Leiqiong Gao
- Department of Neonatology, Children's Hospital of Chongqing Medical University, Ministry of Education Key Laboratory of Child Development and Disorders, China International Science and Technology Cooperation base of Child development and Critical Disorders, Chongqing Key Laboratory of Child Infection and Immunity, Chongqing, 40014, China.,Department of Microbiology, Immunology, and Parasitology, Louisiana State University Health Sciences Center, New Orleans, LA, 70112, USA
| | - Xiancai Rao
- Department of Microbiology, Army Medical University, Chongqing, 400038, China
| | - Jing Wang
- Department of Neonatology, Children's Hospital of Chongqing Medical University, Ministry of Education Key Laboratory of Child Development and Disorders, China International Science and Technology Cooperation base of Child development and Critical Disorders, Chongqing Key Laboratory of Child Infection and Immunity, Chongqing, 40014, China
| | - Hua Yu
- Department of Central Laboratory, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Junru Jiang
- Department of Neonatology, Children's Hospital of Chongqing Medical University, Ministry of Education Key Laboratory of Child Development and Disorders, China International Science and Technology Cooperation base of Child development and Critical Disorders, Chongqing Key Laboratory of Child Infection and Immunity, Chongqing, 40014, China
| | - Wei Zhou
- Department of Neonatology, Children's Hospital of Chongqing Medical University, Ministry of Education Key Laboratory of Child Development and Disorders, China International Science and Technology Cooperation base of Child development and Critical Disorders, Chongqing Key Laboratory of Child Infection and Immunity, Chongqing, 40014, China
| | - Jin Wang
- Phase I Clinical Centre, Beijing Shijitan Hospital, Capital Medical University, Beijing, 100038, China
| | - Yonghong Xiao
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China, 300013
| | - Mengwen Li
- Department of Neonatology, Children's Hospital of Chongqing Medical University, Ministry of Education Key Laboratory of Child Development and Disorders, China International Science and Technology Cooperation base of Child development and Critical Disorders, Chongqing Key Laboratory of Child Infection and Immunity, Chongqing, 40014, China
| | - Yan Zhang
- Department of Neonatology, Children's Hospital of Chongqing Medical University, Ministry of Education Key Laboratory of Child Development and Disorders, China International Science and Technology Cooperation base of Child development and Critical Disorders, Chongqing Key Laboratory of Child Infection and Immunity, Chongqing, 40014, China
| | - Kebin Zhang
- Department of Central Laboratory, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Li Shen
- Department of Microbiology, Immunology, and Parasitology, Louisiana State University Health Sciences Center, New Orleans, LA, 70112, USA.
| | - Ziyu Hua
- Department of Neonatology, Children's Hospital of Chongqing Medical University, Ministry of Education Key Laboratory of Child Development and Disorders, China International Science and Technology Cooperation base of Child development and Critical Disorders, Chongqing Key Laboratory of Child Infection and Immunity, Chongqing, 40014, China.
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81
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Priya K, Sulaiman J, How KY, Yin WF, Chan KG. Production of N-acyl homoserine lactones by Chromobacterium haemolyticum KM2 isolated from the river water in Malaysia. Arch Microbiol 2018; 200:1135-1142. [PMID: 29796703 DOI: 10.1007/s00203-018-1526-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2017] [Revised: 03/16/2018] [Accepted: 05/14/2018] [Indexed: 10/16/2022]
Abstract
Quorum sensing (QS) is a term used to describe cell-to-cell communication that enables bacteria to orchestrate group behaviours according to density of bacterial cells. In Gram-negative bacteria, this signalling system is widely known to regulate a variety of different phenotypes such as antibiotic production and biofilm formation. In this study, we report the production of N-acyl homoserine lactones produced by Chromobacterium haemolyticum strain KM2, a bacterium isolated from a river water of a reserved tropical national park. Preliminary screening of QS activity using biosensor reporter assays indicated that C. haemolyticum strain KM2 produces both short- and long-chain AHLs. Analysis with high-resolution liquid chromatography-mass spectrometry (LC-MS/MS) analysis revealed the production of three AHLs by strain KM2: N-octanoyl-L-homoserine lactone (C8-HSL), N-dodecanoyl-L-homoserine lactone (C12-HSL), and N-3-oxo-dodecanoyl-L-homoserine lactone (OC12-HSL). This bacterial isolate also exhibited strong β-haemolytic activity. To the best of our knowledge, this is the first documentation of QS activity and multiple AHLs production by C. haemolyticum strain KM2.
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Affiliation(s)
- Kumutha Priya
- International Genome Centre, Jiangsu University, Zhenjiang, China.,Division of Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, 50603, Malaysia
| | - Joanita Sulaiman
- Institute for Public Health, National Institutes of Health Malaysia, Jalan Bangsar, 50590, Kuala Lumpur, Malaysia
| | - Kah Yan How
- Division of Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, 50603, Malaysia
| | - Wai-Fong Yin
- International Genome Centre, Jiangsu University, Zhenjiang, China.,Division of Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, 50603, Malaysia
| | - Kok-Gan Chan
- International Genome Centre, Jiangsu University, Zhenjiang, China. .,Division of Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, 50603, Malaysia.
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82
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Yang Y, Zhou M, Hardwidge PR, Cui H, Zhu G. Isolation and Characterization of N-acyl Homoserine Lactone-Producing Bacteria From Cattle Rumen and Swine Intestines. Front Cell Infect Microbiol 2018; 8:155. [PMID: 29868511 PMCID: PMC5954215 DOI: 10.3389/fcimb.2018.00155] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 04/24/2018] [Indexed: 11/15/2022] Open
Abstract
Quorum sensing systems regulate gene expression in response to bacterial population density. Acyl-homoserine lactones are a class of quorum sensing molecules found in cattle rumen that are thought to regulate the gene expression of enterohemorrhagic Escherichia coli and thus help this pathogen survive in animal gastrointestinal tracts. However, the specific bacteria that produce these signaling molecules in bovine and porcine gastrointestinal tracts are unknown. Here we developed methods to concentrate gastrointestinal fluids and screen the bacteria that produce acyl-homoserine lactones. We isolated a Pseudomonas aeruginosa strain YZ1 from cattle rumen, and an Aeromonas hydrophila strain YZ2 from pig intestine. Mass spectrometry analysis of culture supernatants indicated at least three specific classes of acyl-homoserine lactones produced by YZ1, and a C4-acyl-homoserine lactone produced by YZ2. Transformation of E. coli with P. aeruginosa or A. hydrophila luxI homologs,which can produce short- or long-chain acyl-homoserine lactones conferred upon E. coli the ability to synthesize acyl-homoserine lactones and affected gene expression, motility, and acid tolerance of E. coli. This is the first study reporting the isolation and characterization of acyl-homoserine lactone synthase-positive bacteria from cattle rumen and swine intestines.
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Affiliation(s)
- Yang Yang
- Institute of Epigenetics and Epigenomics and College of Animal Science and Technology, Yangzhou University, Yangzhou, China.,Jiangsu Co-Innovation Center for Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, China.,College of Veterinary Medicine, Yangzhou University, Yangzhou, China
| | - Mingxu Zhou
- Jiangsu Co-Innovation Center for Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, China.,College of Veterinary Medicine, Yangzhou University, Yangzhou, China
| | - Philip R Hardwidge
- College of Veterinary Medicine, Kansas State University, Manhattan, KS, United States
| | - Hengmi Cui
- Institute of Epigenetics and Epigenomics and College of Animal Science and Technology, Yangzhou University, Yangzhou, China
| | - Guoqiang Zhu
- Jiangsu Co-Innovation Center for Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, China.,College of Veterinary Medicine, Yangzhou University, Yangzhou, China
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Potrykus M, Hugouvieux‐Cotte‐Pattat N, Lojkowska E. Interplay of classic Exp and specific Vfm quorum sensing systems on the phenotypic features of Dickeya solani strains exhibiting different virulence levels. MOLECULAR PLANT PATHOLOGY 2018; 19:1238-1251. [PMID: 28921772 PMCID: PMC6638156 DOI: 10.1111/mpp.12614] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 08/10/2017] [Accepted: 09/14/2017] [Indexed: 05/31/2023]
Abstract
Bacteria from the genus Dickeya cause severe symptoms on numerous economically important plants. Dickeya solani is the Dickeya species most frequently found on infected potato plants in Europe. D. solani strains from different countries show high genetic homogeneity, but significant differences in their virulence level. Dickeya species possess two quorum sensing (QS) mechanisms: the Exp system based on classic N-acyl-homoserine lactone (AHL) signals and a specific system depending on the production and perception of a molecule of unknown structure, Virulence Factor Modulating (VFM). To study the interplay between these two QS systems, five D. solani strains exhibiting different virulence levels were selected. Mutants were constructed by inactivating genes coding for each QS system. Double mutants were obtained by simultaneous inactivation of genes coding for both QS systems. Most of the D. solani mutants showed an attenuation of chicory maceration and a decreased production of plant cell wall-degrading enzymes (PCWDEs) and motility, but to different degrees depending on the strain. The VFM-QS system seems to regulate virulence in both D. solani and Dickeya dadantii, but the AHL-QS system has greater effects in D. solani than in D. dadantii. The inactivation of both QS systems in D. solani did not reveal any additive effect on the tested features. The inactivation of vfm genes generally has a more dominant effect relative to that of exp genes. Thus, VFM- and AHL-QS systems do not work in synergy to modulate the production of diverse virulence factors and the ability to macerate plant tissue.
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Affiliation(s)
- Marta Potrykus
- Department of Biotechnology, Intercollegiate Faculty of BiotechnologyUniversity of Gdansk and Medical University of Gdansk, Abrahama 58, 80–307GdanskPoland
| | - Nicole Hugouvieux‐Cotte‐Pattat
- UMR5240 Microbiologie Adaptation et PathogénieUniversité Lyon, CNRS, INSA Lyon, Université Claude Bernard Lyon 1F–69622 VilleurbanneFrance
| | - Ewa Lojkowska
- Department of Biotechnology, Intercollegiate Faculty of BiotechnologyUniversity of Gdansk and Medical University of Gdansk, Abrahama 58, 80–307GdanskPoland
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Utari PD, Setroikromo R, Melgert BN, Quax WJ. PvdQ Quorum Quenching Acylase Attenuates Pseudomonas aeruginosa Virulence in a Mouse Model of Pulmonary Infection. Front Cell Infect Microbiol 2018; 8:119. [PMID: 29755959 PMCID: PMC5932173 DOI: 10.3389/fcimb.2018.00119] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 04/03/2018] [Indexed: 01/24/2023] Open
Abstract
Pseudomonas aeruginosa is the predominant pathogen in pulmonary infections associated with cystic fibrosis. Quorum sensing (QS) systems regulate the production of virulence factors and play an important role in the establishment of successful P. aeruginosa infections. Inhibition of the QS system (termed quorum quenching) renders the bacteria avirulent thus serving as an alternative approach in the development of novel antibiotics. Quorum quenching in Gram negative bacteria can be achieved by preventing the accumulation of N-acyl homoserine lactone (AHL) signaling molecule via enzymatic degradation. Previous work by us has shown that PvdQ acylase hydrolyzes AHL signaling molecules irreversibly, thereby inhibiting QS in P. aeruginosa in vitro and in a Caenorhabditis elegans model of P. aeruginosa infection. The aim of the present study is to assess the therapeutic efficacy of intranasally instilled PvdQ acylase in a mouse model of pulmonary P. aeruginosa infection. First, we evaluated the deposition pattern of intranasally administered fluorochrome-tagged PvdQ (PvdQ-VT) in mice at different stages of pulmonary infection by in vivo imaging studies. Following intranasal instillation, PvdQ-VT could be traced in all lung lobes with 42 ± 7.5% of the delivered dose being deposited at 0 h post-bacterial-infection, and 34 ± 5.2% at 72 h post bacterial-infection. We then treated mice with PvdQ during lethal P. aeruginosa pulmonary infection and that resulted in a 5-fold reduction of lung bacterial load and a prolonged survival of the infected animals with the median survival time of 57 hin comparison to 42 h for the PBS-treated group. In a sublethal P. aeruginosa pulmonary infection, PvdQ treatment resulted in less lung inflammation as well as decrease of CXCL2 and TNF-α levels at 24 h post-bacterial-infection by 15 and 20%, respectively. In conclusion, our study has shown therapeutic efficacy of PvdQ acylase as a quorum quenching agent during P. aeruginosa infection.
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Affiliation(s)
- Putri D. Utari
- Department of Chemical and Pharmaceutical Biology, University of Groningen, Groningen, Netherlands
| | - Rita Setroikromo
- Department of Chemical and Pharmaceutical Biology, University of Groningen, Groningen, Netherlands
| | - Barbro N. Melgert
- Department of Pharmacokinetics, Toxicology and Targeting, University of Groningen, Groningen, Netherlands
| | - Wim J. Quax
- Department of Chemical and Pharmaceutical Biology, University of Groningen, Groningen, Netherlands
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85
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Chong YM, How KY, Yin WF, Chan KG. The Effects of Chinese Herbal Medicines on the Quorum Sensing-Regulated Virulence in Pseudomonas aeruginosa PAO1. Molecules 2018; 23:molecules23040972. [PMID: 29690523 PMCID: PMC6017394 DOI: 10.3390/molecules23040972] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Revised: 04/12/2018] [Accepted: 04/13/2018] [Indexed: 12/31/2022] Open
Abstract
The quorum sensing (QS) system has been used by many opportunistic pathogenic bacteria to coordinate their virulence determinants in relation to cell-population density. As antibiotic-resistant bacteria are on the rise, interference with QS has been regarded as a novel way to control bacterial infections. As such, many plant-based natural products have been widely explored for their therapeutic roles. These natural products may contain anti-QS compounds that could block QS signals generation or transmission to combat QS pathogens. In this study, we report the anti-QS activities of four different Chinese herbal plant extracts: Poria cum Radix pini, Angelica dahurica, Rhizoma cibotii and Schizonepeta tenuifolia, on Pseudomonas aeruginosa PAO1. All the plants extracted using hexane, chloroform and methanol were tested and found to impair swarming motility and pyocyanin production in P.aeruginosa PAO1, particularly by Poria cum Radix pini. In addition, all the plant extracts also inhibited violacein production in C.violaceum CV026 up to 50% while bioluminescence activities were reduced in lux-based E. coli biosensors, pSB401 and pSB1075, up to about 57%. These anti-QS properties of the four medicinal plants are the first documentation that demonstrates a potential approach to attenuate pathogens’ virulence determinants.
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Affiliation(s)
- Yee Meng Chong
- Division of Genetics and Molecular Biology, ISB, Faculty of Science, University of Malaya, Kuala Lumpur 50603, Malaysia.
| | - Kah Yan How
- Division of Genetics and Molecular Biology, ISB, Faculty of Science, University of Malaya, Kuala Lumpur 50603, Malaysia.
| | - Wai Fong Yin
- Division of Genetics and Molecular Biology, ISB, Faculty of Science, University of Malaya, Kuala Lumpur 50603, Malaysia.
| | - Kok Gan Chan
- Vice Chancellor Office, Jiangsu University, Zhenjiang 212013, China.
- Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur 50603, Malaysia.
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86
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de Grandi AZ, Pinto UM, Destro MT. Dual-species biofilm of Listeria monocytogenes and Escherichia coli on stainless steel surface. World J Microbiol Biotechnol 2018; 34:61. [PMID: 29651554 DOI: 10.1007/s11274-018-2445-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Accepted: 04/09/2018] [Indexed: 11/25/2022]
Abstract
Listeria monocytogenes is a Gram-positive bacterium commonly associated with foodborne diseases. Due its ability to survive under adverse environmental conditions and to form biofilm, this bacterium is a major concern for the food industry, since it can compromise sanitation procedures and increase the risk of post-processing contamination. Little is known about the interaction between L. monocytogenes and Gram-negative bacteria on biofilm formation. Thus, in order to evaluate this interaction, Escherichia coli and L. monocytogenes were tested for their ability to form biofilms together or in monoculture. We also aimed to evaluate the ability of L. monocytogenes 1/2a and its isogenic mutant strain (ΔprfA ΔsigB) to form biofilm in the presence of E. coli. We assessed the importance of the virulence regulators, PrfA and σB, in this process since they are involved in many aspects of L. monocytogenes pathogenicity. Biofilm formation was assessed using stainless steel AISI 304 #4 slides immersed into brain heart infusion broth, reconstituted powder milk and E. coli preconditioned medium at 25 °C. Our results indicated that a higher amount of biofilm was formed by the wild type strain of L. monocytogenes than by its isogenic mutant, indicating that prfA and sigB are important for biofilm development, especially maturation under our experimental conditions. The presence of E. coli or its metabolites in preconditioned medium did not influence biofilm formation by L. monocytogenes. Our results confirm the possibility of concomitant biofilm formation by L. monocytogenes and E. coli, two bacteria of major significance in the food industry.
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Affiliation(s)
- Aline Zago de Grandi
- Department of Food and Experimental Nutrition, Faculty of Pharmaceutical Sciences, University of São Paulo, Av. Prof. Lineu Prestes 580 B.14, 05508-900, São Paulo, SP, Brazil
| | - Uelinton Manoel Pinto
- Department of Food and Experimental Nutrition, Faculty of Pharmaceutical Sciences, University of São Paulo, Av. Prof. Lineu Prestes 580 B.14, 05508-900, São Paulo, SP, Brazil.
- Food Research Center (FoRC), Faculty of Pharmaceutical Sciences, University of São Paulo, Av. Prof. Lineu Prestes 580 B.14, 05508-900, São Paulo, SP, Brazil.
| | - Maria Teresa Destro
- Department of Food and Experimental Nutrition, Faculty of Pharmaceutical Sciences, University of São Paulo, Av. Prof. Lineu Prestes 580 B.14, 05508-900, São Paulo, SP, Brazil
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87
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Cheng HY, Masiello CA, Del Valle I, Gao X, Bennett GN, Silberg JJ. Ratiometric Gas Reporting: A Nondisruptive Approach To Monitor Gene Expression in Soils. ACS Synth Biol 2018; 7:903-911. [PMID: 29366321 DOI: 10.1021/acssynbio.7b00405] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Fluorescent proteins are ubiquitous tools that are used to monitor the dynamic functions of natural and synthetic genetic circuits. However, these visual reporters can only be used in transparent settings, a limitation that complicates nondisruptive measurements of gene expression within many matrices, such as soils and sediments. We describe a new ratiometric gas reporting method for nondisruptively monitoring gene expression within hard-to-image environmental matrices. With this approach, C2H4 is continuously synthesized by ethylene forming enzyme to provide information on viable cell number, and CH3Br is conditionally synthesized by placing a methyl halide transferase gene under the control of a conditional promoter. We show that ratiometric gas reporting enables the creation of Escherichia coli biosensors that report on acylhomoserine lactone (AHL) autoinducers used for quorum sensing by Gram-negative bacteria. Using these biosensors, we find that an agricultural soil decreases the bioavailable concentration of a long-chain AHL up to 100-fold. We also demonstrate that these biosensors can be used in soil to nondisruptively monitor AHLs synthesized by Rhizobium leguminosarum and degraded by Bacillus thuringiensis. Finally, we show that this new reporting approach can be used in Shewanella oneidensis, a bacterium that lives in sediments.
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88
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Nakayama T, Kawahara R, Kumeda Y, Yamamoto Y. Extended-spectrum β-lactamase-producing Escherichia coli contributes to the survival of cefotaxime-susceptible E. coli under high concentrations of cefotaxime by acquisition of increased AmpC expression. FEMS Microbiol Lett 2018; 365:4816729. [PMID: 29361027 DOI: 10.1093/femsle/fny009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Accepted: 01/17/2018] [Indexed: 12/11/2022] Open
Abstract
Extended-spectrum β-lactamase-producing Escherichia coli (ESBL-E) are becoming increasingly widespread in Vietnam. Antibiotics are detected in many Vietnamese foods; however, the effect of ESBL-E and antibiotic consumption on intestinal bacteria has not been studied sufficiently. Here, we investigated the effect of oral administration of ESBL-E (TB19) and cefotaxime on luminescence-emitting cefotaxime-sensitive E. coli (X14). Mice were given water containing TB19 and then received three injections of 1.0 × 108 CFU of X14 harboring a luciferase gene. The mice were administered 100 μg of cefotaxime and luminescent bacteria were monitored over 24 h, following which luminescent bacteria were isolated from mouse feces. Luminescence continued to be detected in mice administered TB19 24 h after cefotaxime ingestion. Fecal analysis revealed two types of luminescent colonies: cefoxitin-resistant E. coli (X14-R) and Pseudomonas aeruginosa. Pulse-field gel electrophoresis confirmed that X14-R was a clonal strain of X14, suggesting that X14 survived using ESBLs originating from TB19 and acquired cefoxitin resistance due to cefotaxime consumption. Moreover, in vitro analysis of X14 indicated that expression of the ampC gene was upregulated by cefotaxime. Overall, ESBL-E and cefotaxime promoted the expansion of cefoxitin-resistant E. coli in the absence of plasmid-mediated gene transfer.
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Affiliation(s)
- Tatsuya Nakayama
- Division of Biomedical Food Research, National Institute of Health Science, Tokyo 158-8501, Japan.,Center for Global Initiatives, Osaka University, Suita, Osaka 565-0871, Japan
| | - Ryuji Kawahara
- Department of Bacteriology, Osaka Institute of Public Health, Higashinari, Osaka 537-0025, Japan
| | - Yuko Kumeda
- Research Center for Microbial Control, Osaka Prefecture University, Osaka 565-8531, Japan
| | - Yoshimasa Yamamoto
- Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Osaka 565-0871, Japan
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89
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Oral Application of Recombinant Bacillus subtilis Spores to Dogs Results in a Humoral Response against Specific Echinococcus granulosus Paramyosin and Tropomyosin Antigens. Infect Immun 2018; 86:IAI.00495-17. [PMID: 29229735 DOI: 10.1128/iai.00495-17] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 12/05/2017] [Indexed: 01/01/2023] Open
Abstract
Bacillus subtilis is known as an endospore- and biofilm-forming bacterium with probiotic properties. We have recently developed a method for displaying heterologous proteins on the surface of B. subtilis biofilms by introducing the coding sequences of the protein of interest into the bacterial genome to generate a fusion protein linked to the C terminus of the biofilm matrix protein TasA. Although B. subtilis is a regular component of the gut microflora, we constructed a series of recombinant B. subtilis strains that were tested for their ability to be used to immunize dogs following oral application of the spores. Specifically, we tested recombinant spores of B. subtilis carrying either the fluorescent protein mCherry or else selected antigenic peptides (tropomyosin and paramyosin) from Echinococcus granulosus, a zoonotic intestinal tapeworm of dogs and other carnivores. The application of the recombinant B. subtilis spores led to the colonization of the gut with recombinant B. subtilis but did not cause any adverse effect on the health of the animals. As measured by enzyme-linked immunosorbent assay and immunoblotting, the dogs were able to develop a humoral immune response against mCherry as well as against E. granulosus antigenic peptides. Interestingly, the sera of dogs obtained after immunization with recombinant spores of E. granulosus peptides were able to recognize E. granulosus protoscoleces, which represent the infective form of the head of the tapeworms. These results represent an essential step toward the establishment of B. subtilis as an enteric vaccine agent.
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90
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A multi-step approach for testing non-toxic amphiphilic antifouling coatings against marine microfouling at different levels of biological complexity. J Microbiol Methods 2018; 146:104-114. [PMID: 29438719 DOI: 10.1016/j.mimet.2018.02.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 02/09/2018] [Accepted: 02/09/2018] [Indexed: 01/04/2023]
Abstract
Marine biofouling on artificial surfaces such as ship hulls or fish farming nets causes enormous economic damage. The time for the developmental process of antifouling coatings can be shortened by reliable laboratory assays. For designing such test systems, it is important that toxic effects can be excluded, that multiple parameters can be addressed simultaneously and that mechanistic aspects can be included. In this study, a multi-step approach for testing antifouling coatings was established employing photoautotrophic biofilm formation of marine microorganisms in micro- and mesoscoms. Degree and pattern of biofilm formation was determined by quantification of chlorophyll fluorescence. For the microcosms, co-cultures of diatoms and a heterotrophic bacterium were exposed to fouling-release coatings. For the mesocosms, a novel device was developed that permits parallel quantification of a multitude of coatings under defined conditions with varying degrees of shear stress. Additionally, the antifouling coatings were tested for leaching of potential compounds and finally tested in sea trials. This multistep-approach revealed that the individual steps led to consistent results regarding antifouling activity of the coatings. Furthermore, the novel mesocosm system can be employed for advanced antifouling analysis including metagenomic approaches for determination of microbial diversity attaching to different coatings under changing shear forces.
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91
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Lachish River event monitored for toxicity using bioluminescent reporter organisms. THE EUROBIOTECH JOURNAL 2018. [DOI: 10.2478/ebtj-2018-0008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Abstract
The Lachish River has suffered from recurring pollution incidents for the past decade. On October 11th, 2017, another contamination in the river was sighted, as thousands of dead fish were found floating. Samples from the river were retrieved and tested through a whole cell bioluminescent bacterial bioreporter system as well as conventional analytical methods, and the results from both methods were analyzed and compared, even though initially these two collecting events were not coordinated. The information acquired from the whole cell reporter was consistent with that obtained from conventional methods. Both approaches indicated a large concentration of microorganisms as deduced from K802NR E. coli strain reaction and coliforms count. The high water conductivity measured in collected samples were closer downstream, and attributed to the diffusion of salts from the Mediterranean Sea which affected bacterial viability as seen from the decreased reaction of E. coli strains TV1061 and DPD2794. In addition, the bacterial indicators’ kinetic patterns have shown indication for the presence of a genotoxic substance from only one of the collection sites, which was tested positive for the herbicide Metazachlor, itself known to have genotoxic effects. The correlation between both approaches, along with the biosensor’s ability to assess biological influences, suggests that the whole cell bioluminescent bacterial bioreporter bioassay as an easy, simple and efficient approach for water toxicity monitoring.
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92
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Li SZ, Xu R, Ahmar M, Goux-Henry C, Queneau Y, Soulère L. Influence of the d/l configuration of N-acyl-homoserine lactones (AHLs) and analogues on their Lux-R dependent quorum sensing activity. Bioorg Chem 2018; 77:215-222. [PMID: 29367078 DOI: 10.1016/j.bioorg.2018.01.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Revised: 12/15/2017] [Accepted: 01/02/2018] [Indexed: 01/26/2023]
Abstract
Whereas l-3-oxo-hexanoyl homoserine lactone (OHHL) is the active enantiomer of the of LuxR-regulated quorum sensing (QS) autoinducer, its d isomer is implicitly considered as inactive. The present work aims to clarify this l-specificity and investigate whether it extends to some analogues in the acyl homoserine lactone (AHL) family. For this purpose, OHHL and a series of AHL analogs were synthesized in racemic and enantiomerically pure d and l forms and their ability to induce or attenuate bioluminescence in the LuxR-dependent QS system was evaluated. In this study, l-isomers are confirmed as either the only, or as the most active, enantiomers. However, in several cases, especially for the natural ligand of LuxR (OHHL) and the very similar AHL agonist analogue 2, the d-isomer cannot be considered as totally inactive on QS. Molecular modelling suggests that when the lactone moiety of the d-isomer is able to twist, enabling the lactone carbonyl group and the amide function to interact with the key residues in the binding site, then the d-isomer can exhibit some activity.
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Affiliation(s)
- Si-Zhe Li
- Univ Lyon, INSA Lyon, CNRS, Université Lyon 1, CPE Lyon, UMR 5246, ICBMS, Institut de Chimie et de Biochimie Moléculaires et Supramoléculaires, Laboratoire de Chimie Organique et Bioorganique Bât. J. Verne, 20 avenue A. Einstein, F-69621 Villeurbanne, France
| | - Rui Xu
- Univ Lyon, INSA Lyon, CNRS, Université Lyon 1, CPE Lyon, UMR 5246, ICBMS, Institut de Chimie et de Biochimie Moléculaires et Supramoléculaires, Laboratoire de Chimie Organique et Bioorganique Bât. J. Verne, 20 avenue A. Einstein, F-69621 Villeurbanne, France
| | - Mohammed Ahmar
- Univ Lyon, INSA Lyon, CNRS, Université Lyon 1, CPE Lyon, UMR 5246, ICBMS, Institut de Chimie et de Biochimie Moléculaires et Supramoléculaires, Laboratoire de Chimie Organique et Bioorganique Bât. J. Verne, 20 avenue A. Einstein, F-69621 Villeurbanne, France
| | - Catherine Goux-Henry
- Univ Lyon, Université Lyon 1, CNRS, INSA Lyon, CPE Lyon, UMR 5246, ICBMS, Institut de Chimie et de Biochimie Moléculaires et Supramoléculaires, CASYEN Bât Curien (CPE) 43, Bd du 11 Novembre 1918, 69622 Villeurbanne cedex, France
| | - Yves Queneau
- Univ Lyon, INSA Lyon, CNRS, Université Lyon 1, CPE Lyon, UMR 5246, ICBMS, Institut de Chimie et de Biochimie Moléculaires et Supramoléculaires, Laboratoire de Chimie Organique et Bioorganique Bât. J. Verne, 20 avenue A. Einstein, F-69621 Villeurbanne, France.
| | - Laurent Soulère
- Univ Lyon, INSA Lyon, CNRS, Université Lyon 1, CPE Lyon, UMR 5246, ICBMS, Institut de Chimie et de Biochimie Moléculaires et Supramoléculaires, Laboratoire de Chimie Organique et Bioorganique Bât. J. Verne, 20 avenue A. Einstein, F-69621 Villeurbanne, France.
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93
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Abstract
One relevant aspect for understanding the bottlenecks that modulate the spread of resistance among bacterial pathogens consists in the effect that the acquisition of resistance may have on the microbial physiology . Whereas studies on the effect of acquiring resistance of bacterial growth are frequently performed, more detailed analyses aiming to understand in depth the cross talk between resistance and virulence, including bacterial communication are less frequent. The bacterial quorum sensing system, is an important intraspecific and interspecific communication system highly relevant for many physiological processes, including virulence and bacterial/host interactions. Some works have shown that the acquisition of antibiotic resistance may impair the quorum sensing response. In addition, some antibiotics as antimicrobial peptides can affect the production and accumulation of the quorum sensing signal molecules. Given the relevance that this system has in the bacterial behavior in the human host, it is important to study the effect that the acquisition of antibiotic resistance may have on the production of quorum sensing signals. In this chapter we present a set of methods for measuring quorum sensing signals based on the use of biosensor strains, either coupled to Thin Layer Chromatography or for performing automated luminometry/spectrophotometry assays. We use Pseudomonas aeruginosa as bacterial model because it has a complex quorum system than encloses different signals. Namely, P. aeruginosa quorum sensing system consists in three different interconnected regulatory networks, each one presenting a specific autoinducer molecule: the las system, which signal is N-(3-oxo-dodecanoyl)-L-homoserine lactone, the rhl system, which signal is N-butanoyl-homoserine lactone and the pqs system, which signals are 2-heptyl-3-hydroxy-4(1H)-quinolone together with its immediate precursor 2-heptyl-4-hydroxy-quinoline.
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94
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Kviatkovski I, Shushan S, Oron Y, Frumin I, Amir D, Secundo L, Livne E, Weissbrod A, Sobel N, Helman Y. Smelling Pseudomonas aeruginosa infections using a whole-cell biosensor - An alternative for the gold-standard culturing assay. J Biotechnol 2017; 267:45-49. [PMID: 29292129 DOI: 10.1016/j.jbiotec.2017.12.023] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Revised: 12/07/2017] [Accepted: 12/27/2017] [Indexed: 12/24/2022]
Abstract
Improved easy-to-use diagnostic tools for infections are in strong demand worldwide. Yet, despite dramatic advances in diagnostic technologies, the gold-standard remains culturing. Here we offer an alternative tool demonstrating that a bacterial biosensor can efficiently detect Pseudomonas aeruginosa infections in patients suffering from otitis externa. Detection was based on specific binding between the biosensor and 2-aminoacetophenone (2-AA), a volatile produced by P. aeruginosa in high amounts. We collected pus samples from ears of 26 subjects exhibiting symptoms of otitis externa. Detection of P. aeruginosa using the biosensor was compared to detection using gold-standard culturing assay and to gas-chromatograph-mass-spectrometry (GC-MS) analyses of 2-AA. The biosensor strain test matched the culture assay in 24 samples (92%) and the GC-MS analyses in 25 samples (96%). With this result in hand, we designed a device containing a whole-cell luminescent biosensor combined with a photo-multiplier tube. This device allowed detection of 2-AA at levels as low as 2 nmol, on par with detection level of GC-MS. The results of the described study demonstrate that the volatile 2-AA serves as an effective biomarker for P. aeruginosa in ear infections, and that activation of the biosensor strain by 2-AA provides a unique opportunity to design an easy-to-use device that can specifically detect P. aeruginosa infections.
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Affiliation(s)
- Igor Kviatkovski
- Department of Plant Pathology and Microbiology, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel
| | - Sagit Shushan
- Department of Neurobiology, Weizmann Institute of Science, Rehovot 76100, Israel; Department of Otolaryngology-Head and Neck Surgery, Edith Wolfson Hospital, Holon, Israel
| | - Yahav Oron
- Department of Otolaryngology-Head and Neck Surgery, Edith Wolfson Hospital, Holon, Israel; Tel-Aviv Sourasky Medical Center, Tel-Aviv University, Israel
| | - Idan Frumin
- Department of Neurobiology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Daniel Amir
- Department of Neurobiology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Lavi Secundo
- Department of Neurobiology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Eitan Livne
- Department of Neurobiology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Aharon Weissbrod
- Department of Neurobiology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Noam Sobel
- Department of Neurobiology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Yael Helman
- Department of Plant Pathology and Microbiology, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel.
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95
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Melkina OE, Koval VS, Ivanov AA, Zhuze AL, Zavilgelsky GB. DNA sequence-specific dimeric bisbenzimidazoles DBP(n) and DBPA(n) as inhibitors of H-NS silencing in bacterial cells. Microbiol Res 2017; 207:75-82. [PMID: 29458871 DOI: 10.1016/j.micres.2017.11.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 11/07/2017] [Accepted: 11/12/2017] [Indexed: 11/16/2022]
Abstract
DNA sequence-specific fluorescent dimeric bisbenzimidazoles DBP(n) and DBPA(n), noncovalently interacting with A-T pairs in the minor groove of double-stranded DNA were used for studying and monitoring the expression of histone-like H-NS-dependent promoters. Histone-like H-NS selectively binds to AT-rich segments of DNA and silences a large number of genes in bacterial chromosomes. The H-NS-dependent promoters of Quorum Sensing (QS)-regulated lux operons of the marine bacteria mesophilic Aliivibrio fischeri, psychrophilic Aliivibrio logei were used. Escherichia coli lux biosensors were constructed by cloning fragments bearing QS-regulated promoters into the vector, thereby placing each fragment upstream of the promoterless Photorhabdus luminescens luxCDABE genes. It was shown that the dimeric bisbenzimidazoles DBP(n) and DBPA(n) counteract the H-NS silencing activity. Thus, the presence of DBP(n) or DBPA(n) in the medium leads to an approximately 10-100-fold increase in the level of transcription of QS promoters in E. coli hns+. The largest decrease in the level of H-NS repression was observed using ligands containing a linker with a length of ca. 18Å, such as DBP(2) and DBPA(2). Ligands containing linkers with n=1 and 3 are an order of magnitude less active; ligands with n=4 are inactive. DBPA(2) exhibits activity starting with a concentration of 0.5μM; the minimum concentration of DBP(2) is 5-7 times higher. It is suggested that A-T pairs located at five nucleotide pair intervals, which correspond to the linker length in highly active ligands with n=2, play a key role in the structure of H-NS-binding sites in QS-regulated promoters.
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Affiliation(s)
- Olga E Melkina
- State Research Institute of Genetics and Selection of Industrial Microorganisms (GosNIIgenetika), Moscow, 117545, Russia
| | - Vasilii S Koval
- Engelhardt Institute of Molecular Biology, Moscow, 119991, Russia
| | - Alexander A Ivanov
- Emanuel Institute of Biochemical Physics RAS, Kosygin st., 4, Moscow, 119334, Russia
| | - Alexei L Zhuze
- Engelhardt Institute of Molecular Biology, Moscow, 119991, Russia
| | - Gennadii B Zavilgelsky
- State Research Institute of Genetics and Selection of Industrial Microorganisms (GosNIIgenetika), Moscow, 117545, Russia.
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96
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Host modification of a bacterial quorum-sensing signal induces a phenotypic switch in bacterial symbionts. Proc Natl Acad Sci U S A 2017; 114:E8488-E8497. [PMID: 28923926 DOI: 10.1073/pnas.1706879114] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Bacterial communities colonize epithelial surfaces of most animals. Several factors, including the innate immune system, mucus composition, and diet, have been identified as determinants of host-associated bacterial communities. Here we show that the early branching metazoan Hydra is able to modify bacterial quorum-sensing signals. We identified a eukaryotic mechanism that enables Hydra to specifically modify long-chain 3-oxo-homoserine lactones into their 3-hydroxy-HSL counterparts. Expression data revealed that Hydra's main bacterial colonizer, Curvibacter sp., responds differentially to N-(3-hydroxydodecanoyl)-l-homoserine lactone (3OHC12-HSL) and N-(3-oxododecanoyl)-l-homoserine lactone (3OC12-HSL). Investigating the impacts of the different N-acyl-HSLs on host colonization elucidated that 3OHC12-HSL allows and 3OC12-HSL represses host colonization of Curvibacter sp. These results show that an animal manipulates bacterial quorum-sensing signals and that this modification leads to a phenotypic switch in the bacterial colonizers. This mechanism may enable the host to manipulate the gene expression and thereby the behavior of its bacterial colonizers.
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97
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Al-Yousef HM, Ahmed AF, Al-Shabib NA, Laeeq S, Khan RA, Rehman MT, Alsalme A, Al-Ajmi MF, Khan MS, Husain FM. Onion Peel Ethylacetate Fraction and Its Derived Constituent Quercetin 4'- O-β-D Glucopyranoside Attenuates Quorum Sensing Regulated Virulence and Biofilm Formation. Front Microbiol 2017; 8:1675. [PMID: 28928721 PMCID: PMC5591837 DOI: 10.3389/fmicb.2017.01675] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 08/18/2017] [Indexed: 12/04/2022] Open
Abstract
The resistance and pathogenesis of bacteria could be related to their ability to sense and respond to population density, termed quorum sensing (QS). Inhibition of the QS system is considered as a novel strategy for the development of antipathogenic agents, especially for combating drug-resistant bacterial infections. In the present study, the anti-QS activity of Onion peel ethylacetate fraction (ONE) was tested against Chromobacterium violaceum CV12472 and Pseudomonas aeruginosa PAO1. ONE inhibit the QS-mediated virulence factors production such as violacein in C. violaceum and elastase, pyocyanin in P. aeruginosa. Further, the treatment with sub-MICs of ONE significantly inhibited the QS-mediated biofilm formation, EPS (Extracellular polymeric substances) production and swarming motility. Further, quercetin 4′-O-β-D glucopyranoside (QGP) was isolated from ONE and its anti-QS potential was confirmed after observing significant inhibition of QS-controlled virulence factors such as violacein, elastase, pyocyanin and biofilm formation in test pathogens. Molecular docking analysis predicted that QGP should be able to bind at the active sites of Vfr and LasR, and if so blocks the entry of active sites in Vfr and LasR.
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Affiliation(s)
- Hanan M Al-Yousef
- Department of Pharmacognosy, College of Pharmacy, King Saud UniversityRiyadh, Saudi Arabia
| | - Atallah F Ahmed
- Department of Pharmacognosy, College of Pharmacy, King Saud UniversityRiyadh, Saudi Arabia
| | - Nasser A Al-Shabib
- Department of Food Science and Nutrition, Faculty of Food and Agricultural Sciences, King Saud UniversityRiyadh, Saudi Arabia
| | - Sameen Laeeq
- Department of Applied Chemistry, Faculty of Engineering and Technology, Aligarh Muslim UniversityAligarh, India
| | - Rais A Khan
- Department of Chemistry, College of Sciences, King Saud UniversityRiyadh, Saudi Arabia
| | - Md T Rehman
- Department of Pharmacognosy, College of Pharmacy, King Saud UniversityRiyadh, Saudi Arabia
| | - Ali Alsalme
- Department of Chemistry, College of Sciences, King Saud UniversityRiyadh, Saudi Arabia
| | - Mohamed F Al-Ajmi
- Department of Pharmacognosy, College of Pharmacy, King Saud UniversityRiyadh, Saudi Arabia
| | - Mohammad S Khan
- Department of Agricultural Microbiology, Aligarh Muslim UniversityAligarh, India
| | - Fohad M Husain
- Department of Food Science and Nutrition, Faculty of Food and Agricultural Sciences, King Saud UniversityRiyadh, Saudi Arabia
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98
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Enhanced removal of Escherichia coli O157:H7 and Listeria innocua from fresh lettuce leaves using surfactants during simulated washing. Food Control 2017. [DOI: 10.1016/j.foodcont.2017.03.032] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Abdel-Latif HMR, Khashaba AMA. Subchronic toxicity of Nile tilapia with different exposure routes to Microcystis aeruginosa: Histopathology, liver functions, and oxidative stress biomarkers. Vet World 2017; 10:955-963. [PMID: 28919690 PMCID: PMC5591486 DOI: 10.14202/vetworld.2017.955-963] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2017] [Accepted: 07/28/2017] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Toxic cyanobacterial blooms (Microcystis aeruginosa contains microcystins [MCs]) have been reported to induce clinicopathological alterations as well as different oxidative stress in aquatic biota. AIM Three-week subchronic exposure experiment was carried out on Nile tilapia, to determine their effects on fish behavior, tissues, liver functions, antioxidant enzymes, and lipid peroxidation. MATERIALS AND METHODS Fish were exposed to four main treatments; orally fed diet plus toxic cells of M. aeruginosa (containing 3500 µg/g MC-LR), immersion in 500 µg MC-LR/L, intraperitoneal injection of M. aeruginosa MC-LR with a dose of 0.1 ml of extracted toxin at a dose of 200 μg/kg bwt, and the fourth one served as a control group, then the fish were sacrificed at the end of 3rd week of exposure. RESULTS The results revealed no recorded mortality with obvious behavioral changes and an enlarged liver with the congested gall bladder. Histopathology demonstrated fragmentation, hyalinization, and necrosis of the subcutaneous musculature marked fatty degeneration, and vacuolation of hepatopancreatic cells with adhesion of the secondary gill lamellae associated with severe leukocytic infiltration. Furthermore, liver functions enzymes (aspartate aminotransferase and alanine aminotransferase, and the activities of glutathione peroxidase, glutathione reductase, lipid peroxidase, and catalase enzymes) were significantly increased in all treatments starting from the 2nd week as compared to the control levels. CONCLUSION In this context, the study addresses the possible toxicological impacts of toxic M. aeruginosa contain MC-LR to Nile tilapia, and the results investigated that MC-LR is toxic to Nile tilapia in different routes of exposure as well as different doses.
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Affiliation(s)
- H M R Abdel-Latif
- Department of Poultry and Fish Diseases, Faculty of Veterinary Medicine, Alexandria University (Matrouh Branch), Fuka City, Box: 51744, Matrouh Province, Egypt
| | - A M Abou Khashaba
- Department of Food Inspection, Animal Health Research Institute, Dokki, Giza Province, Egypt
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Abstract
Polymicrobial interactions are complex and can influence the course of an infection, as is the case when two or more species exhibit a synergism that produces a disease state not seen with any of the individual species alone. Cell-to-cell signaling is key to many of these interactions, but little is understood about how the host environment influences polymicrobial interactions or signaling between bacteria. Chronic wounds are typically polymicrobial, with Staphylococcus aureus and Pseudomonas aeruginosa being the two most commonly isolated species. While P. aeruginosa readily kills S. aureusin vitro, the two species can coexist for long periods together in chronic wound infections. In this study, we investigated the ability of components of the wound environment to modulate interactions between P. aeruginosa and S. aureus We demonstrate that P. aeruginosa quorum sensing is inhibited by physiological levels of serum albumin, which appears to bind and sequester some homoserine lactone quorum signals, resulting in the inability of P. aeruginosa to produce virulence factors that kill S. aureus These data could provide important clues regarding the virulence of P. aeruginosa in albumin-depleted versus albumin-rich infection sites and an understanding of the nature of friendly versus antagonistic interactions between P. aeruginosa and S. aureus.
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