101
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Shin D, Nagarajan R. Enzymatic Assays to Investigate Acyl-Homoserine Lactone Autoinducer Synthases. Methods Mol Biol 2018; 1673:161-176. [PMID: 29130172 PMCID: PMC5766357 DOI: 10.1007/978-1-4939-7309-5_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Bacteria use chemical molecules called autoinducers as votes to poll their numerical strength in a colony. This polling mechanism, commonly referred to as quorum sensing, enables bacteria to build a social network and provide a collective response for fighting off common threats. In Gram-negative bacteria, AHL synthases synthesize acyl-homoserine lactone (AHL) autoinducers to turn on the expression of several virulent genes including biofilm formation, protease secretion, and toxin production. Therefore, inhibiting AHL signal synthase would limit quorum sensing and virulence. In this chapter, we describe four enzymatic methods that could be adopted to investigate a broad array of AHL synthases. The enzymatic assays described here should accelerate our mechanistic understanding of quorum-sensing signal synthesis that could pave the way for discovery of potent antivirulence compounds.
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Affiliation(s)
- Daniel Shin
- Department of Chemistry and Biochemistry, Boise State University, 1910 University Drive, Boise, ID, 83725, USA
| | - Rajesh Nagarajan
- Department of Chemistry and Biochemistry, Boise State University, 1910 University Drive, Boise, ID, 83725, USA.
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102
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张 晓. The Dynamical Modeling Studies of the Quorum Sensing Mechanism in Bacteria. Biophysics (Nagoya-shi) 2018. [DOI: 10.12677/biphy.2018.62002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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103
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Schaefer AL, Harwood CS, Greenberg EP. "Hot Stuff": The Many Uses of a Radiolabel Assay in Detecting Acyl-Homoserine Lactone Quorum-Sensing Signals. Methods Mol Biol 2018; 1673:35-47. [PMID: 29130162 DOI: 10.1007/978-1-4939-7309-5_3] [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] [Indexed: 02/02/2023]
Abstract
Many Proteobacteria synthesize acyl-homoserine lactone (AHL) molecules for use as signals in cell density-dependent gene regulation known as quorum sensing (QS) and response. AHL detection protocols are essential to QS researchers and several techniques are available, including a 14C-AHL radiolabel assay. This assay is based on the uptake of radiolabeled methionine by living cells and conversion of the radiolabel into S-adenosylmethionine (SAM). The radiolabeled SAM is then incorporated into AHL signal by an AHL synthase enzyme. Here we describe a methodology to perform the AHL radiolabel assay, which is unbiased, relatively fast, and very sensitive compared to other AHL detection protocols.
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Affiliation(s)
- Amy L Schaefer
- Department of Microbiology, University of Washington, Seattle, WA, USA.
| | | | - E Peter Greenberg
- Department of Microbiology, University of Washington, Seattle, WA, USA.
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104
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Nature to the natural rescue: Silencing microbial chats. Chem Biol Interact 2017; 280:86-98. [PMID: 29247642 DOI: 10.1016/j.cbi.2017.12.018] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Revised: 11/22/2017] [Accepted: 12/12/2017] [Indexed: 12/13/2022]
Abstract
Communication is the sole means by which effective networking and co-existence is accomplished amongst living beings. Microbes have their own chit-chats. Science has overheard these microbial gossips and have concluded that these aren't just informal communications, but carefully coordinated signals that plan their effective strategies. Tracking one such signal molecule, N-acyl homoserine lactone (AHL), led to a fundamental understanding to microbial quorum sensing (QS). Furtherance of research sought for ways to cut off communication between these virulent forms, so as to hinder their combinatorial attacks through quorum sensing inhibitors (QSIs). A clear understanding of the inhibitors of these microbial communication systems is vital to destroy their networking and co-working. The current review, consolidates the solutions for QSIs offered from natural sources against these micro components, that are capable of slaughtering even nature's most fit entity-man. The applications of effective out sourcing of this QSI technologies and the need for development are discussed. The importance of silencing this microbial chatter to various aspects of human life and their implications are discussed and elaborated.
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105
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Vázquez-Martínez J, Nieto-Álvarez E, Ramírez-Chávez E, Molina-Torres J. Enzymatic Method for N-Acyl Homoserine Lactones Synthesis Using Immobilized Candida antarctica Lipase. Catal Letters 2017. [DOI: 10.1007/s10562-017-2261-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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106
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Quorum Sensing in Burkholderia pseudomallei and Other Burkholderia species. CURRENT TROPICAL MEDICINE REPORTS 2017. [DOI: 10.1007/s40475-017-0127-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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107
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Engevik MA, Versalovic J. Biochemical Features of Beneficial Microbes: Foundations for Therapeutic Microbiology. Microbiol Spectr 2017; 5:10.1128/microbiolspec.BAD-0012-2016. [PMID: 28984235 PMCID: PMC5873327 DOI: 10.1128/microbiolspec.bad-0012-2016] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Indexed: 12/15/2022] Open
Abstract
Commensal and beneficial microbes secrete myriad products which target the mammalian host and other microbes. These secreted substances aid in bacterial niche development, and select compounds beneficially modulate the host and promote health. Microbes produce unique compounds which can serve as signaling factors to the host, such as biogenic amine neuromodulators, or quorum-sensing molecules to facilitate inter-bacterial communication. Bacterial metabolites can also participate in functional enhancement of host metabolic capabilities, immunoregulation, and improvement of intestinal barrier function. Secreted products such as lactic acid, hydrogen peroxide, bacteriocins, and bacteriocin-like substances can also target the microbiome. Microbes differ greatly in their metabolic potential and subsequent host effects. As a result, knowledge about microbial metabolites will facilitate selection of next-generation probiotics and therapeutic compounds derived from the mammalian microbiome. In this article we describe prominent examples of microbial metabolites and their effects on microbial communities and the mammalian host.
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Affiliation(s)
- Melinda A Engevik
- Department of Pathology & Immunology, Baylor College of Medicine, Houston, TX 77030 and Department of Pathology, Texas Children's Hospital, Houston, TX 77030
| | - James Versalovic
- Department of Pathology & Immunology, Baylor College of Medicine, Houston, TX 77030 and Department of Pathology, Texas Children's Hospital, Houston, TX 77030
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108
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Antibiofilm agents: A new perspective for antimicrobial strategy. J Microbiol 2017; 55:753-766. [PMID: 28956348 DOI: 10.1007/s12275-017-7274-x] [Citation(s) in RCA: 96] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 08/31/2017] [Accepted: 08/31/2017] [Indexed: 02/08/2023]
Abstract
Biofilms are complex microbial architectures that attach to surfaces and encase microorganisms in a matrix composed of self-produced hydrated extracellular polymeric substances (EPSs). In biofilms, microorganisms become much more resistant to antimicrobial treatments, harsh environmental conditions, and host immunity. Biofilm formation by microbial pathogens greatly enhances survival in hosts and causes chronic infections that result in persistent inflammation and tissue damages. Currently, it is believed over 80% of chronic infectious diseases are mediated by biofilms, and it is known that conventional antibiotic medications are inadequate at eradicating these biofilm-mediated infections. This situation demands new strategies for biofilm-associated infections, and currently, researchers focus on the development of antibiofilm agents that are specific to biofilms, but are nontoxic, because it is believed that this prevents the development of drug resistance. Here, we review the most promising antibiofilm agents undergoing intensive research and development.
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109
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Ramadan Y, Amro H, Nora F, Khaled AA. Quorum sensing signal production by sponge-associated bacteria isolated from the Red Sea, Egypt. ACTA ACUST UNITED AC 2017. [DOI: 10.5897/ajb2017.16078] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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110
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Molecular basis for the substrate specificity of quorum signal synthases. Proc Natl Acad Sci U S A 2017; 114:9092-9097. [PMID: 28784791 DOI: 10.1073/pnas.1705400114] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
In several Proteobacteria, LuxI-type enzymes catalyze the biosynthesis of acyl-homoserine lactones (AHL) signals using S-adenosyl-l-methionine and either cellular acyl carrier protein (ACP)-coupled fatty acids or CoA-aryl/acyl moieties as progenitors. Little is known about the molecular mechanism of signal biosynthesis, the basis for substrate specificity, or the rationale for donor specificity for any LuxI member. Here, we present several cocrystal structures of BjaI, a CoA-dependent LuxI homolog that represent views of enzyme complexes that exist along the reaction coordinate of signal synthesis. Complementary biophysical, structure-function, and kinetic analysis define the features that facilitate the unusual acyl conjugation with S-adenosylmethionine (SAM). We also identify the determinant that establishes specificity for the acyl donor and identify residues that are critical for acyl/aryl specificity. These results highlight how a prevalent scaffold has evolved to catalyze quorum signal synthesis and provide a framework for the design of small-molecule antagonists of quorum signaling.
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111
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Kalia M, Singh PK, Yadav VK, Yadav BS, Sharma D, Narvi SS, Mani A, Agarwal V. Structure based virtual screening for identification of potential quorum sensing inhibitors against LasR master regulator in Pseudomonas aeruginosa. Microb Pathog 2017; 107:136-143. [DOI: 10.1016/j.micpath.2017.03.026] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Revised: 02/21/2017] [Accepted: 03/24/2017] [Indexed: 10/19/2022]
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112
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Turan NB, Chormey DS, Büyükpınar Ç, Engin GO, Bakirdere S. Quorum sensing: Little talks for an effective bacterial coordination. Trends Analyt Chem 2017. [DOI: 10.1016/j.trac.2017.03.007] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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113
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Singh S, Singh SK, Chowdhury I, Singh R. Understanding the Mechanism of Bacterial Biofilms Resistance to Antimicrobial Agents. Open Microbiol J 2017; 11:53-62. [PMID: 28553416 PMCID: PMC5427689 DOI: 10.2174/1874285801711010053] [Citation(s) in RCA: 376] [Impact Index Per Article: 53.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Revised: 02/15/2017] [Accepted: 02/15/2017] [Indexed: 01/08/2023] Open
Abstract
A biofilm is a group of microorganisms, that causes health problems for the patients with indwelling medical devices via attachment of cells to the surface matrix. It increases the resistance of a microorganism for antimicrobial agents and developed the human infection. Current strategies are removed or prevent the microbial colonies from the medical devices, which are attached to the surfaces. This will improve the clinical outcomes in favor of the patients suffering from serious infectious diseases. Moreover, the identification and inhibition of genes, which have the major role in biofilm formation, could be the effective approach for health care systems. In a current review article, we are highlighting the biofilm matrix and molecular mechanism of antimicrobial resistance in bacterial biofilms.
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Affiliation(s)
- Shriti Singh
- Department of Kriya Sharir, Institute of Medical Sciences, Banaras Hindu University, Varanasi- 221 005 UP India
| | - Santosh Kumar Singh
- Department of Microbiology, Biochemistry and Immunology, Morehouse School of Medicine, Atlanta, GA, USA
| | - Indrajit Chowdhury
- Department of Obstetrics and Gynecology; Morehouse School of Medicine, Atlanta, GA, USA
| | - Rajesh Singh
- Department of Microbiology, Biochemistry and Immunology, Morehouse School of Medicine, Atlanta, GA, USA
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114
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Baumgardt K, Melior H, Madhugiri R, Thalmann S, Schikora A, McIntosh M, Becker A, Evguenieva-Hackenberg E. RNase E and RNase J are needed for S-adenosylmethionine homeostasis in Sinorhizobium meliloti. MICROBIOLOGY-SGM 2017; 163:570-583. [PMID: 28141492 DOI: 10.1099/mic.0.000442] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The ribonucleases (RNases) E and J play major roles in E. coli and Bacillus subtilis, respectively, and co-exist in Sinorhizobium meliloti. We analysed S. meliloti 2011 mutants with mini-Tn5 insertions in the corresponding genes rne and rnj and found many overlapping effects. We observed similar changes in mRNA levels, including lower mRNA levels of the motility and chemotaxis related genes flaA, flgB and cheR and higher levels of ndvA (important for glucan export). The acyl-homoserine lactone (AHL) levels were also higher during exponential growth in both RNase mutants, despite no increase in the expression of the sinI AHL synthase gene. Furthermore, several RNAs from both mutants migrated aberrantly in denaturing gels at 300 V but not under stronger denaturing conditions at 1300 V. The similarities between the two mutants could be explained by increased levels of the key methyl donor S-adenosylmethionine (SAM), since this may result in faster AHL synthesis leading to higher AHL accumulation as well as in uncontrolled methylation of macromolecules including RNA, which may strengthen RNA secondary structures. Indeed, we found that in both mutants the N6-methyladenosine content was increased almost threefold and the SAM level was increased at least sevenfold. Complementation by induced ectopic expression of the respective RNase restored the AHL and SAM levels in each of the mutants. In summary, our data show that both RNase E and RNase J are needed for SAM homeostasis in S. meliloti.
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Affiliation(s)
- Kathrin Baumgardt
- Institute of Microbiology and Molecular Biology, Heinrich-Buff-Ring 26-32, D-35392 Giessen, Germany.,Present address: CNRS, Institut de Biologie Physico-Chimique, 13 Rue Pierre et Marie Curie, 75005 Paris, France
| | - Hendrik Melior
- Institute of Microbiology and Molecular Biology, Heinrich-Buff-Ring 26-32, D-35392 Giessen, Germany
| | - Ramakanth Madhugiri
- Institute of Microbiology and Molecular Biology, Heinrich-Buff-Ring 26-32, D-35392 Giessen, Germany.,Present address: Institute of Medical Virology, Biomedical Research Center, Justus Liebig University, Schubertstr. 81, D 35392 Giessen, Germany
| | - Sebastian Thalmann
- Institute of Microbiology and Molecular Biology, Heinrich-Buff-Ring 26-32, D-35392 Giessen, Germany
| | - Adam Schikora
- Institute of Phytopathology and Applied Zoology, Heinrich-Buff-Ring 26-32, D-35392 Giessen, Germany.,Present address: Julius Kühn-Institut, Federal Research Centre for Cultivated Plants (JKI), Institute for Epidemiology and Pathogen Diagnostics, Messeweg 11/12, 38104, Brunswick, Germany
| | - Matthew McIntosh
- Centre of Synthetic Microbiology, Hans-Meerwein-Straße 6, D-35043 Marburg, Germany
| | - Anke Becker
- Centre of Synthetic Microbiology, Hans-Meerwein-Straße 6, D-35043 Marburg, Germany
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115
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Alagarasan G, Aswathy KS, Madhaiyan M. Shoot the Message, Not the Messenger-Combating Pathogenic Virulence in Plants by Inhibiting Quorum Sensing Mediated Signaling Molecules. FRONTIERS IN PLANT SCIENCE 2017; 8:556. [PMID: 28446917 PMCID: PMC5388769 DOI: 10.3389/fpls.2017.00556] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 03/28/2017] [Indexed: 06/07/2023]
Abstract
Immunity, virulence, biofilm formation, and survival in the host environment are regulated by the versatile nature of density dependent microbial cell signaling, also called quorum sensing (QS). The QS molecules can associate with host plant tissues and, at times, cause a change in its gene expression at the downstream level through inter-kingdom cross talking. Progress in controlling QS through fungicide/bactericide in pathogenic microscopic organisms has lead to a rise of antibiotic resistance pathogens. Here, we review the application of selective quorum quenching (QQ) endophytes to control phytopathogens that are shared by most, if not all, terrestrial plant species as well as aquatic plants. Allowing the plants to posses endophytic colonies through biotization will be an additional and a sustainable encompassing methodology resulting in attenuated virulence rather than killing the pathogens. Furthermore, the introduced endophytes could serve as a potential biofertilizer and bioprotection agent, which in turn increases the PAMP- triggered immunity and hormonal systemic acquired resistance (SAR) in plants through SA-JA-ET signaling systems. This paper discusses major challenges imposed by QS and QQ application in biotechnology.
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Affiliation(s)
- Ganesh Alagarasan
- Department of Plant Molecular Biology and Biotechnology, Indira Gandhi Krishi VishwavidyalayaRaipur, India
| | - Kumar S. Aswathy
- Department of Agricultural Microbiology, Tamilnadu Agricultural UniversityCoimbatore, India
| | - Munusamy Madhaiyan
- Biomaterials and Biocatalyst, Temasek Lifesciences Laboratory, National University of SingaporeSingapore, Singapore
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116
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Production of rhamnolipids-producing enzymes of Pseudomonas in E. coli and structural characterization. Front Chem Sci Eng 2017. [DOI: 10.1007/s11705-017-1637-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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117
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118
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Lentini R, Martín NY, Forlin M, Belmonte L, Fontana J, Cornella M, Martini L, Tamburini S, Bentley WE, Jousson O, Mansy SS. Two-Way Chemical Communication between Artificial and Natural Cells. ACS CENTRAL SCIENCE 2017; 3:117-123. [PMID: 28280778 PMCID: PMC5324081 DOI: 10.1021/acscentsci.6b00330] [Citation(s) in RCA: 151] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2016] [Indexed: 05/02/2023]
Abstract
Artificial cells capable of both sensing and sending chemical messages to bacteria have yet to be built. Here we show that artificial cells that are able to sense and synthesize quorum signaling molecules can chemically communicate with V. fischeri, V. harveyi, E. coli, and P. aeruginosa. Activity was assessed by fluorescence, luminescence, RT-qPCR, and RNA-seq. Two potential applications for this technology were demonstrated. First, the extent to which artificial cells could imitate natural cells was quantified by a type of cellular Turing test. Artificial cells capable of sensing and in response synthesizing and releasing N-3-(oxohexanoyl)homoserine lactone showed a high degree of likeness to natural V. fischeri under specific test conditions. Second, artificial cells that sensed V. fischeri and in response degraded a quorum signaling molecule of P. aeruginosa (N-(3-oxododecanoyl)homoserine lactone) were constructed, laying the foundation for future technologies that control complex networks of natural cells.
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Affiliation(s)
- Roberta Lentini
- CIBIO, University of Trento, via Sommarive 9, 38123 Povo, Italy
| | - Noël Yeh Martín
- CIBIO, University of Trento, via Sommarive 9, 38123 Povo, Italy
| | - Michele Forlin
- CIBIO, University of Trento, via Sommarive 9, 38123 Povo, Italy
| | - Luca Belmonte
- CIBIO, University of Trento, via Sommarive 9, 38123 Povo, Italy
| | - Jason Fontana
- CIBIO, University of Trento, via Sommarive 9, 38123 Povo, Italy
| | | | - Laura Martini
- CIBIO, University of Trento, via Sommarive 9, 38123 Povo, Italy
| | | | - William E. Bentley
- Institute
for Bioscience and Biotechnology Research, University of Maryland, College
Park, Maryland 20742, United States
| | - Olivier Jousson
- CIBIO, University of Trento, via Sommarive 9, 38123 Povo, Italy
| | - Sheref S. Mansy
- CIBIO, University of Trento, via Sommarive 9, 38123 Povo, Italy
- E-mail:
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119
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Tan KH, How KY, Tan JY, Yin WF, Chan KG. Cloning and Characterization of the Autoinducer Synthase Gene from Lipid-Degrading Bacterium Cedecea neteri. Front Microbiol 2017; 8:72. [PMID: 28197135 PMCID: PMC5281573 DOI: 10.3389/fmicb.2017.00072] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Accepted: 01/11/2017] [Indexed: 11/13/2022] Open
Abstract
The process of intercellular communication among bacteria, termed quorum sensing (QS), is mediated by small diffusible molecules known as the autoinducers. QS allows the population to react to the change of cell density in unison, in processes such as biofilm formation, plasmid conjugation, virulence, motility and root nodulation. In Gram-negative proteobacteria, N-acyl homoserine lactone (AHL) is the common "language" to coordinate gene expression. This signaling molecule is usually synthesized by LuxI-type proteins. We have previously discovered that a rare bacterium, Cedecea neteri, exhibits AHL-type QS activity. With information generated from genome sequencing, we have identified the luxIR gene pair responsible for AHL-type QS and named it cneIR. In this study, we have cloned and expressed the 636 bp luxI homolog in an Escherichia coli host for further characterization. Our findings show that E. coli harboring cneI produced the same AHL profile as the wild type C. neteri, with the synthesis of AHL known as N-butyryl-homoserine lactone. This 25 kDa LuxI homolog shares high similarity with other AHL synthases from closely related species. This work is the first documentation of molecular cloning and characterization of luxI homolog from C. neteri.
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Affiliation(s)
- Kian-Hin Tan
- Division of Genetic and Molecular Biology, Institute of Biological Sciences, Faculty of Science, University of Malaya Kuala Lumpur, Malaysia
| | - Kah-Yan How
- Division of Genetic and Molecular Biology, Institute of Biological Sciences, Faculty of Science, University of Malaya Kuala Lumpur, Malaysia
| | - Jia-Yi Tan
- Division of Genetic and Molecular Biology, Institute of Biological Sciences, Faculty of Science, University of Malaya Kuala Lumpur, Malaysia
| | - Wai-Fong Yin
- Division of Genetic and Molecular Biology, Institute of Biological Sciences, Faculty of Science, University of Malaya Kuala Lumpur, Malaysia
| | - Kok-Gan Chan
- Division of Genetic and Molecular Biology, Institute of Biological Sciences, Faculty of Science, University of Malaya Kuala Lumpur, Malaysia
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120
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Talagrand-Reboul E, Jumas-Bilak E, Lamy B. The Social Life of Aeromonas through Biofilm and Quorum Sensing Systems. Front Microbiol 2017; 8:37. [PMID: 28163702 PMCID: PMC5247445 DOI: 10.3389/fmicb.2017.00037] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 01/06/2017] [Indexed: 01/25/2023] Open
Abstract
Bacteria of the genus Aeromonas display multicellular behaviors herein referred to as “social life”. Since the 1990s, interest has grown in cell-to-cell communication through quorum sensing signals and biofilm formation. As they are interconnected, these two self-organizing systems deserve to be considered together for a fresh perspective on the natural history and lifestyles of aeromonads. In this review, we focus on the multicellular behaviors of Aeromonas, i.e., its social life. First, we review and discuss the available knowledge at the molecular and cellular levels for biofilm and quorum sensing. We then discuss the complex, subtle, and nested interconnections between the two systems. Finally, we focus on the aeromonad multicellular coordinated behaviors involved in heterotrophy and virulence that represent technological opportunities and applied research challenges.
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Affiliation(s)
- Emilie Talagrand-Reboul
- Équipe Pathogènes Hydriques Santé Environnements, UMR 5569 HSM, Université de MontpellierMontpellier, France; Département d'Hygiène Hospitalière, Centre Hospitalier Régional Universitaire (CHRU) de MontpellierMontpellier, France
| | - Estelle Jumas-Bilak
- Équipe Pathogènes Hydriques Santé Environnements, UMR 5569 HSM, Université de MontpellierMontpellier, France; Département d'Hygiène Hospitalière, Centre Hospitalier Régional Universitaire (CHRU) de MontpellierMontpellier, France
| | - Brigitte Lamy
- Équipe Pathogènes Hydriques Santé Environnements, UMR 5569 HSM, Université de MontpellierMontpellier, France; Département de Bactériologie, Centre Hospitalier Universitaire (CHU) de NiceNice, France
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121
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Kannan S, Ashokkumar K, Krishnamoorthy G, Dhasayan A, Marudhamuthu M. Monitoring surfactant mediated defence of gastrointestinal Proteus mirabilis DMTMMK1 against pathogenic consortia of Vibrio cholerae. RSC Adv 2017. [DOI: 10.1039/c7ra01934c] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Schematic representation of the biosurfactant production and evaluation of anti-pathogenic potential.
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Affiliation(s)
- Suganya Kannan
- Department of Microbial Technology
- School of Biological Sciences
- Madurai Kamaraj University
- Madurai-625021
- India
| | - Krithika Ashokkumar
- Department of Microbial Technology
- School of Biological Sciences
- Madurai Kamaraj University
- Madurai-625021
- India
| | - Govindan Krishnamoorthy
- Department of Microbial Technology
- School of Biological Sciences
- Madurai Kamaraj University
- Madurai-625021
- India
| | - Asha Dhasayan
- Aquatic Animal Health and Environment Division
- Central Institute of Brackish Water Aquaculture (ICAR-CIBA)
- Chennai 600 028
- India
| | - Murugan Marudhamuthu
- Department of Microbial Technology
- School of Biological Sciences
- Madurai Kamaraj University
- Madurai-625021
- India
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122
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Characterization of the Candida albicans Amino Acid Permease Family: Gap2 Is the Only General Amino Acid Permease and Gap4 Is an S-Adenosylmethionine (SAM) Transporter Required for SAM-Induced Morphogenesis. mSphere 2016; 1:mSphere00284-16. [PMID: 28028545 PMCID: PMC5177730 DOI: 10.1128/msphere.00284-16] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Accepted: 11/28/2016] [Indexed: 11/20/2022] Open
Abstract
Candida albicans is a commensal organism that can thrive in many niches in its human host. The environmental conditions at these different niches differ quite a bit, and this fungus must be able to sense these changes and adapt its metabolism to them. Apart from glucose and other sugars, the uptake of amino acids is very important. This is underscored by the fact that the C. albicans genome encodes 6 orthologues of the Saccharomyces. cerevisiae general amino acid permease Gap1 and many other amino acid transporters. In this work, we characterize these six permeases and we show that C. albicans Gap2 is the functional orthologue of ScGap1 and that C. albicans Gap4 is an orthologue of ScSam3, an S-adenosylmethionine (SAM) transporter. Furthermore, we show that Gap4 is required for SAM-induced morphogenesis, an important virulence factor of C. albicans. Amino acids are key sources of nitrogen for growth of Candida albicans. In order to detect and take up these amino acids from a broad range of different and changing nitrogen sources inside the host, this fungus must be able to adapt via its expression of genes for amino acid uptake and further metabolism. We analyzed six C. albicans putative general amino acid permeases based on their homology to the Saccharomyces cerevisiae Gap1 general amino acid permease. We generated single- and multiple-deletion strains and found that, based on growth assays and transcriptional or posttranscriptional regulation, Gap2 is the functional orthologue to ScGap1, with broad substrate specificity. Expression analysis showed that expression of all GAP genes is under control of the Csy1 amino acid sensor, which is different from the situation in S. cerevisiae, where the expression of ScGAP1 is not regulated by Ssy1. We show that Gap4 is the functional orthologue of ScSam3, the only S-adenosylmethionine (SAM) transporter in S. cerevisiae, and we report that Gap4 is required for SAM-induced morphogenesis. IMPORTANCECandida albicans is a commensal organism that can thrive in many niches in its human host. The environmental conditions at these different niches differ quite a bit, and this fungus must be able to sense these changes and adapt its metabolism to them. Apart from glucose and other sugars, the uptake of amino acids is very important. This is underscored by the fact that the C. albicans genome encodes 6 orthologues of the Saccharomyces. cerevisiae general amino acid permease Gap1 and many other amino acid transporters. In this work, we characterize these six permeases and we show that C. albicans Gap2 is the functional orthologue of ScGap1 and that C. albicans Gap4 is an orthologue of ScSam3, an S-adenosylmethionine (SAM) transporter. Furthermore, we show that Gap4 is required for SAM-induced morphogenesis, an important virulence factor of C. albicans.
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Abbas HA, Shaldam MA. Glyceryl trinitrate is a novel inhibitor of quorum sensing in Pseudomonas aeruginosa. Afr Health Sci 2016; 16:1109-1117. [PMID: 28479904 DOI: 10.4314/ahs.v16i4.29] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Targeting quorum sensing is an alternative approach to antibiotics.Targeting quorum sensing-regulated virulence will disarm the pathogen without exerting pressure on its growth. As a result, emergence of resistance is avoided and the immune system can easily eradicate bacteria. OBJECTIVES Investigation of the possible inhibition of quorum sensing-regulated virulence of Pseudomonas aeruginosa by glyceryltrinitrate. METHODS The quorum sensing inhibiting activity of glyceryl trinitrate was assessed by inhibition of violacein production in Chromobacterium violaceum ATCC 12472. Its ability to inhibit pyocyanin, protease, biofilm and tolerance to oxidative stress was evaluated. Docking study was performed to study the interference of glyceryl trinitrate with the binding of autoinducers with LasR and rhlR receptors. RESULTS Glyceryl trinitrate exerted a significant biofilm inhibiting and eradicating activities. It decreased the production of quorum-sensing dependent violacein production. It significantly inhibited the production of pyocyanin and protease and diminished the tolerance against oxidative stress. Molecular docking study showed that glyceryl trinitrate interferes with the binding of autoinducers to their receptors. It could bind to Las Rand rhlr receptors with binding energy of -93.47 and -77.23, respectively. CONCLUSION Glyceryl trinitrate can be an antivirulence agent in the treatment of Pseudomonas aeruginosa topical infections such as burn infections.
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Affiliation(s)
- Hisham A Abbas
- Department of Microbiology and Immunology, Faculty of Pharmacy, Zagazig University, Zagazig, Egypt
| | - Moutaz A Shaldam
- Department of Medicinal Chemistry, Faculty of Pharmacy, Delta University for Science and Technology, Gamasa, Egypt
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Huang YH, Lin JS, Ma JC, Wang HH. Functional Characterization of Triclosan-Resistant Enoyl-acyl-carrier Protein Reductase (FabV) in Pseudomonas aeruginosa. Front Microbiol 2016; 7:1903. [PMID: 27965638 PMCID: PMC5126088 DOI: 10.3389/fmicb.2016.01903] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 11/14/2016] [Indexed: 12/16/2022] Open
Abstract
Pseudomonas aeruginosa is extremely resistant to triclosan. Previous studies have shown that P. aeruginosa encodes a triclosan-resistant enoyl-acyl-carrier protein reductase (ENR), FabV, and that deletion of fabV causes P. aeruginosa to be extremely sensitive to triclosan. In this report, we complemented a P. aeruginosa fabV deletion strain with several triclosan-resistant ENR encoding genes, including Vibrio cholerae fabV, Bacillus subtilis fabL and Enterococcus faecalis fabK. All complemented strains restored triclosan resistance to the level of the wild-type strain, which confirmed that triclosan-resistant ENR allows P. aeruginosa to be extremely resistant to triclosan. Moreover, fabV exhibits pleiotropic effects. Deletion of fabV led P. aeruginosa to show attenuated swarming motility, decreased rhamnolipid, pyoverdine and acyl-homoserine lactones (AHLs) production. Complementation of the fabV mutant with any one ENR encoding gene could restore these features to some extent, in comparison with the wild-type strain. Furthermore, we found that addition of exogenous AHLs could restore the fabV mutant strain to swarm on semisolid plates and to produce more virulence factors than the fabV mutant strain. These findings indicate that deletion of fabV reduced the activity of ENR in P. aeruginosa, decreased fatty acid synthesis, and subsequently depressed the production of AHLs and other virulence factors, which finally may led to a reduction in the pathogenicity of P. aeruginosa. Therefore, fabV should be an ideal target for the control of P. aeruginosa infectivity.
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Affiliation(s)
- Yong-Heng Huang
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University Guangzhou, China
| | - Jin-Shui Lin
- Shaanxi Engineering and Technological Research Center for Conversation and Utilization of Regional Biological Resources, College of Life Sciences, Yan'an University Yan'an, China
| | - Jin-Cheng Ma
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University Guangzhou, China
| | - Hai-Hong Wang
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University Guangzhou, China
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Corral Lugo A, Daddaoua A, Ortega A, Morel B, Díez Peña AI, Espinosa-Urgel M, Krell T. Purification and characterization of Pseudomonas aeruginosa LasR expressed in acyl-homoserine lactone free Escherichia coli cultures. Protein Expr Purif 2016; 130:107-114. [PMID: 27756565 DOI: 10.1016/j.pep.2016.10.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 10/06/2016] [Accepted: 10/14/2016] [Indexed: 11/25/2022]
Abstract
Quorum sensing systems are essential for bacterial communication. We report here the purification and characterization of the Pseudomonas aeruginosa LasR quorum sensing regulator purified from lysates of E. coli cultures grown in the absence of added acyl-homoserine lactones (AHL). We show by isothermal titration calorimetry that LasR recognizes different AHLs with an affinity of approximately 1 μM. The affinity of LasR for its cognate 3-Oxo-C12-AHL was similar to that of other AHLs, indicating that this regulator has not evolved to preferentially recognize its cognate AHL. The α-helical content as determined by CD spectroscopy was found to be in agreement with the corresponding value derived from the homology model. Analytical ultracentrifugation studies show that LasR is a mixture of monomers and dimers and that AHL binding does not alter its oligomeric state. Thermal unfolding studies indicate that LasR has a significant thermal stability and that AHL binding does not significantly alter the unfolding temperature. Two LasR-DNA complexes were observed in electrophoretic mobility shift assays using the hcnABC promoter that has two lux boxes. Taken together, data indicate that the presence of AHLs is not a requisite for correct LasR protein folding. The protein is able to bind AHL ligands in a reversible manner, revising initial concepts of this regulator. The availability of AHL-free protein will permit further studies to determine more precisely its mode of action.
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Affiliation(s)
- Andrés Corral Lugo
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, C/ Prof. Albareda, 1, 18008 Granada, Spain
| | - Abdelali Daddaoua
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, C/ Prof. Albareda, 1, 18008 Granada, Spain
| | - Alvaro Ortega
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, C/ Prof. Albareda, 1, 18008 Granada, Spain
| | - Bertrand Morel
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, C/ Prof. Albareda, 1, 18008 Granada, Spain
| | - Ana Isabel Díez Peña
- Department of Physical Chemistry, Faculty of Chemistry, Regional Campus of International Excellence "Campus Mare Nostrum", University of Murcia, 30071 Murcia, Spain
| | - Manuel Espinosa-Urgel
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, C/ Prof. Albareda, 1, 18008 Granada, Spain
| | - Tino Krell
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, C/ Prof. Albareda, 1, 18008 Granada, Spain.
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Wei G, Lo C, Walsh C, Hiller NL, Marculescu R. In Silico Evaluation of the Impacts of Quorum Sensing Inhibition (QSI) on Strain Competition and Development of QSI Resistance. Sci Rep 2016; 6:35136. [PMID: 27734907 PMCID: PMC5062075 DOI: 10.1038/srep35136] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Accepted: 09/26/2016] [Indexed: 01/08/2023] Open
Abstract
As understanding of bacterial regulatory systems and pathogenesis continues to increase, QSI has been a major focus of research. However, recent studies have shown that mechanisms of resistance to quorum sensing (QS) inhibitors (QSIs) exist, calling into question their clinical value. We propose a computational framework that considers bacteria genotypes relative to QS genes and QS-regulated products including private, quasi-public, and public goods according to their impacts on bacterial fitness. Our results show (1) QSI resistance spreads when QS positively regulates the expression of private or quasi-public goods. (2) Resistance to drugs targeting secreted compounds downstream of QS for a mix of private, public, and quasi-public goods also spreads. (3) Changing the micro-environment during treatment with QSIs may decrease the spread of resistance. At fundamental-level, our simulation framework allows us to directly quantify cell-cell interactions and biofilm dynamics. Practically, the model provides a valuable tool for the study of QSI-based therapies, and the simulations reveal experimental paths that may guide QSI-based therapies in a manner that avoids or decreases the spread of QSI resistance.
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Affiliation(s)
- Guopeng Wei
- Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Chieh Lo
- Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Connor Walsh
- Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh, PA, USA
| | - N Luisa Hiller
- Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Radu Marculescu
- Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh, PA, USA
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127
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The fitness burden imposed by synthesising quorum sensing signals. Sci Rep 2016; 6:33101. [PMID: 27616328 PMCID: PMC5018880 DOI: 10.1038/srep33101] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 08/12/2016] [Indexed: 12/20/2022] Open
Abstract
It is now well established that bacterial populations utilize cell-to-cell signaling (quorum-sensing, QS) to control the production of public goods and other co-operative behaviours. Evolutionary theory predicts that both the cost of signal production and the response to signals should incur fitness costs for producing cells. Although costs imposed by the downstream consequences of QS have been shown, the cost of QS signal molecule (QSSM) production and its impact on fitness has not been examined. We measured the fitness cost to cells of synthesising QSSMs by quantifying metabolite levels in the presence of QSSM synthases. We found that: (i) bacteria making certain QSSMs have a growth defect that exerts an evolutionary cost, (ii) production of QSSMs negatively correlates with intracellular concentrations of QSSM precursors, (iii) the production of heterologous QSSMs negatively impacts the production of a native QSSM that shares common substrates, and (iv) supplementation with exogenously added metabolites partially rescued growth defects imposed by QSSM synthesis. These data identify the sources of the fitness costs incurred by QSSM producer cells, and indicate that there may be metabolic trade-offs associated with QS signaling that could exert selection on how signaling evolves.
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128
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Xanthomonas campestris FabH is required for branched-chain fatty acid and DSF-family quorum sensing signal biosynthesis. Sci Rep 2016; 6:32811. [PMID: 27595587 PMCID: PMC5011732 DOI: 10.1038/srep32811] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 08/16/2016] [Indexed: 11/24/2022] Open
Abstract
Xanthomonas campestris pv. campestris (Xcc), a Gram-negative phytopathogenic bacterium, causes black rot disease of cruciferous vegetables. Although Xcc has a complex fatty acid profile comprised of straight-chain fatty acids and branched-chain fatty acids (BCFAs), and encodes a complete set of genes required for fatty acid synthesis, there is still little known about the mechanism of BCFA synthesis. We reported that expression of Xcc fabH restores the growth of Ralstonia solanacearum fabH mutant, and this allows the R. solanacearum fabH mutant to produce BCFAs. Using in vitro assays, we demonstrated that Xcc FabH is able to condense branched-chain acyl-CoAs with malonyl-ACP to initiate BCFA synthesis. Moreover, although the fabH gene is essential for growth of Xcc, it can be replaced with Escherichia coli fabH, and Xcc mutants failed to produce BCFAs. These results suggest that Xcc does not have an obligatory requirement for BCFAs. Furthermore, Xcc mutants lost the ability to produce cis-11-methyl-2-dodecenoic acid, a diffusible signal factor (DSF) required for quorum sensing of Xcc, which confirms that the fatty acid synthetic pathway supplies the intermediates for DSF signal biosynthesis. Our study also showed that replacing Xcc fabH with E. coli fabH affected Xcc pathogenesis in host plants.
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Singh BN, Prateeksha, Upreti DK, Singh BR, Defoirdt T, Gupta VK, De Souza AO, Singh HB, Barreira JCM, Ferreira ICFR, Vahabi K. Bactericidal, quorum quenching and anti-biofilm nanofactories: a new niche for nanotechnologists. Crit Rev Biotechnol 2016; 37:525-540. [PMID: 27684212 DOI: 10.1080/07388551.2016.1199010] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Despite several conventional potent antibacterial therapies, bacterial infections pose a significant threat to human health because they are emerging as the leading cause of death worldwide. Due to the development of antibiotic resistance in bacteria, there is a pressing demand to discover novel approaches for developing more effective therapies to treat multidrug-resistant bacterial strains and biofilm-associated infections. Therefore, attention has been especially devoted to a new and emerging branch of science "nanotechnology" to design non-conventional antimicrobial chemotherapies. A range of nanomaterials and nano-sized carriers for conventional antimicrobial agents have fully justified their potential to combat bacterial diseases by reducing cell viability, by attenuating quorum sensing, and by inhibiting/or eradicating biofilms. This communication summarizes emerging nano-antimicrobial therapies in treating bacterial infections, particularly using antibacterial, quorum quenching, and anti-biofilm nanomaterials as new approaches to tackle the current challenges in combating infectious diseases.
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Affiliation(s)
- Brahma N Singh
- a Pharmacognosy & Ethnopharmacology Division , CSIR-National Botanical Research Institute , Lucknow , India
| | - Prateeksha
- a Pharmacognosy & Ethnopharmacology Division , CSIR-National Botanical Research Institute , Lucknow , India
| | - Dalip K Upreti
- b Lichenology laboratory , Plant Biodiversity and Conservation Biology Division, CSIR-National Botanical Research Institute , Lucknow , Uttar Pradesh , India
| | - Braj Raj Singh
- c TERI-Deakin Nanobiotechnology Centre, TERI Gram, The Energy and Resources Institute, Gurgaon , Haryana , India.,d Centre of Excellence in Materials Science (Nanomaterials), Z. H. College of Engineering and Technology , Aligarh Muslim University, Aligarh , Uttar Pradesh , India
| | - Tom Defoirdt
- d Centre of Excellence in Materials Science (Nanomaterials), Z. H. College of Engineering and Technology , Aligarh Muslim University, Aligarh , Uttar Pradesh , India.,e Laboratory of Aquaculture & Artemia Reference Center , Ghent University , Gent , Belgium
| | - Vijai K Gupta
- f Molecular Glyco-biotechnology Group, Discipline of Biochemistry , School of Natural Sciences, National University of Ireland Galway , Galway , Ireland
| | | | - Harikesh Bahadur Singh
- h Mycology & Plant Pathology, Institute of Agricultural Sciences, Banaras Hindu University , Varanasi , Uttar Pardesh , India
| | - João C M Barreira
- i Mountain Research Centre (CIMO), ESA, Polytechnic Institute of Bragança , Campus de Santa Apolónia , Bragança , Portugal
| | - Isabel C F R Ferreira
- i Mountain Research Centre (CIMO), ESA, Polytechnic Institute of Bragança , Campus de Santa Apolónia , Bragança , Portugal
| | - Khabat Vahabi
- j Biologisch-Pharmazeutische Fakultät , Institut für Allgemeine Botanik und Pflanzenphysiologie, Friedrich-Schiller Universität Jena , Jena , Germany
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Huang J, Shi Y, Zeng G, Gu Y, Chen G, Shi L, Hu Y, Tang B, Zhou J. Acyl-homoserine lactone-based quorum sensing and quorum quenching hold promise to determine the performance of biological wastewater treatments: An overview. CHEMOSPHERE 2016; 157:137-151. [PMID: 27213243 DOI: 10.1016/j.chemosphere.2016.05.032] [Citation(s) in RCA: 146] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Revised: 04/21/2016] [Accepted: 05/11/2016] [Indexed: 06/05/2023]
Abstract
Quorum sensing (QS) is a communication process between cells, in which bacteria secrete and sense the specific chemicals, and regulate gene expression in response to population density. Quorum quenching (QQ) blocks QS system, and inhibits gene expression mediating bacterial behaviors. Given the extensive research of acyl-homoserine lactone (AHL) signals, existences and effects of AHL-based QS and QQ in biological wastewater treatments are being subject to high concern. This review summarizes AHL structure, synthesis mode, degradation mechanisms, analytical methods, environmental factors, AHL-based QS and QQ mechanisms. The existences and roles of AHL-based QS and QQ in biomembrane processes, activated sludge processes and membrane bioreactors are summarized and discussed, and corresponding exogenous regulation strategy by selective enhancement of AHL-based QS or QQ coexisting in biological wastewater treatments is suggested. Such strategies including the addition of AHL signals, AHL-producing bacteria as well as quorum quenching enzyme or bacteria can effectively improve wastewater treatment performance without killing or limiting bacterial survival and growth. This review will present the theoretical and practical cognition for bacterial AHL-based QS and QQ, suggest the feasibility of exogenous regulation strategies in biological wastewater treatments, and provide useful information to scientists and engineers who work in this field.
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Affiliation(s)
- Jinhui Huang
- College of Environmental Science and Engineering, Hunan University, Changsha, Hunan, 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha, Hunan, 410082, China.
| | - Yahui Shi
- College of Environmental Science and Engineering, Hunan University, Changsha, Hunan, 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha, Hunan, 410082, China
| | - Guangming Zeng
- College of Environmental Science and Engineering, Hunan University, Changsha, Hunan, 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha, Hunan, 410082, China
| | - Yanling Gu
- College of Environmental Science and Engineering, Hunan University, Changsha, Hunan, 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha, Hunan, 410082, China
| | - Guiqiu Chen
- College of Environmental Science and Engineering, Hunan University, Changsha, Hunan, 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha, Hunan, 410082, China
| | - Lixiu Shi
- College of Environmental Science and Engineering, Hunan University, Changsha, Hunan, 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha, Hunan, 410082, China
| | - Yi Hu
- College of Environmental Science and Engineering, Hunan University, Changsha, Hunan, 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha, Hunan, 410082, China
| | - Bi Tang
- College of Environmental Science and Engineering, Hunan University, Changsha, Hunan, 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha, Hunan, 410082, China
| | - Jianxin Zhou
- College of Environmental Science and Engineering, Hunan University, Changsha, Hunan, 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha, Hunan, 410082, China
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Welsh MA, Blackwell HE. Chemical probes of quorum sensing: from compound development to biological discovery. FEMS Microbiol Rev 2016; 40:774-94. [PMID: 27268906 DOI: 10.1093/femsre/fuw009] [Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/06/2016] [Indexed: 01/20/2023] Open
Abstract
Bacteria can utilize chemical signals to coordinate the expression of group-beneficial behaviors in a method of cell-cell communication called quorum sensing (QS). The discovery that QS controls the production of virulence factors and biofilm formation in many common pathogens has driven an explosion of research aimed at both deepening our fundamental understanding of these regulatory networks and developing chemical agents that can attenuate QS signaling. The inherently chemical nature of QS makes studying these pathways with small molecule tools a complementary approach to traditional microbiology techniques. Indeed, chemical tools are beginning to yield new insights into QS regulation and provide novel strategies to inhibit QS. Here, we review the most recent advances in the development of chemical probes of QS systems in Gram-negative bacteria, with an emphasis on the opportunistic pathogen Pseudomonas aeruginosa We first describe reports of novel small molecule modulators of QS receptors and QS signal synthases. Next, in several case studies, we showcase how chemical tools have been deployed to reveal new knowledge of QS biology and outline lessons for how researchers might best target QS to combat bacterial virulence. To close, we detail the outstanding challenges in the field and suggest strategies to overcome these issues.
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Affiliation(s)
- Michael A Welsh
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave., Madison, WI 53706, USA
| | - Helen E Blackwell
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave., Madison, WI 53706, USA
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Nikolaev EV, Sontag ED. Quorum-Sensing Synchronization of Synthetic Toggle Switches: A Design Based on Monotone Dynamical Systems Theory. PLoS Comput Biol 2016; 12:e1004881. [PMID: 27128344 PMCID: PMC4851387 DOI: 10.1371/journal.pcbi.1004881] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2015] [Accepted: 03/23/2016] [Indexed: 11/22/2022] Open
Abstract
Synthetic constructs in biotechnology, biocomputing, and modern gene therapy interventions are often based on plasmids or transfected circuits which implement some form of “on-off” switch. For example, the expression of a protein used for therapeutic purposes might be triggered by the recognition of a specific combination of inducers (e.g., antigens), and memory of this event should be maintained across a cell population until a specific stimulus commands a coordinated shut-off. The robustness of such a design is hampered by molecular (“intrinsic”) or environmental (“extrinsic”) noise, which may lead to spontaneous changes of state in a subset of the population and is reflected in the bimodality of protein expression, as measured for example using flow cytometry. In this context, a “majority-vote” correction circuit, which brings deviant cells back into the required state, is highly desirable, and quorum-sensing has been suggested as a way for cells to broadcast their states to the population as a whole so as to facilitate consensus. In this paper, we propose what we believe is the first such a design that has mathematically guaranteed properties of stability and auto-correction under certain conditions. Our approach is guided by concepts and theory from the field of “monotone” dynamical systems developed by M. Hirsch, H. Smith, and others. We benchmark our design by comparing it to an existing design which has been the subject of experimental and theoretical studies, illustrating its superiority in stability and self-correction of synchronization errors. Our stability analysis, based on dynamical systems theory, guarantees global convergence to steady states, ruling out unpredictable (“chaotic”) behaviors and even sustained oscillations in the limit of convergence. These results are valid no matter what are the values of parameters, and are based only on the wiring diagram. The theory is complemented by extensive computational bifurcation analysis, performed for a biochemically-detailed and biologically-relevant model that we developed. Another novel feature of our approach is that our theorems on exponential stability of steady states for homogeneous or mixed populations are valid independently of the number N of cells in the population, which is usually very large (N ≫ 1) and unknown. We prove that the exponential stability depends on relative proportions of each type of state only. While monotone systems theory has been used previously for systems biology analysis, the current work illustrates its power for synthetic biology design, and thus has wider significance well beyond the application to the important problem of coordination of toggle switches. For the last decade, outstanding progress has been made, and considerable practical experience has accumulated, in the construction of elementary genetic circuits that perform various tasks, such as memory storage and logical operations, in response to both exogenous and endogenous stimuli. Using modern molecular “plug-and-play” technologies, various (re-)programmable cellular populations can be engineered, and they can be combined into more complex cellular systems. Among all engineered synthetic circuits, a toggle, a robust bistable switch leading to a binary response dynamics, is the simplest basic synthetic biology device, analogous to the “flip-flop” or latch in electronic design, and it plays a key role in biotechnology, biocomputing, and proposed gene therapies. However, despite many remarkable properties of the existing toggle designs, they must be tightly controlled in order to avoid spontaneous switching between different expression states (loss of long-term memory) or even the breakdown of stability through the generation of stable oscillations. To address this concrete challenge, we have developed a new design for quorum-sensing synthetic toggles, based on monotone dynamical systems theory. Our design is endowed with strong theoretical guarantees that completely exclude unpredictable chaotic behaviors in the limit of convergence, as well as undesired stable oscillations, and leads to robust consensus states.
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Affiliation(s)
- Evgeni V. Nikolaev
- Department of Mathematics and Center for Quantitative Biology, Rutgers, The State University of New Jersey, Piscataway, New Jersy, United States of America
| | - Eduardo D. Sontag
- Department of Mathematics and Center for Quantitative Biology, Rutgers, The State University of New Jersey, Piscataway, New Jersy, United States of America
- * E-mail:
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GcsR, a TyrR-Like Enhancer-Binding Protein, Regulates Expression of the Glycine Cleavage System in Pseudomonas aeruginosa PAO1. mSphere 2016; 1:mSphere00020-16. [PMID: 27303730 PMCID: PMC4894688 DOI: 10.1128/msphere.00020-16] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 04/06/2016] [Indexed: 02/01/2023] Open
Abstract
Glycine is required for various cellular functions, including cell wall synthesis, protein synthesis, and the biosynthesis of several important metabolites. Regulating levels of glycine metabolism allows P. aeruginosa to maintain the metabolic flux of glycine through several pathways, including the metabolism of glycine to produce other amino acids, entry into the trichloroacetic acid cycle, and the production of virulence factors such as hydrogen cyanide. In this study, we characterized GcsR, a transcriptional regulator that activates the expression of genes involved in P. aeruginosa PAO1 glycine metabolism. Our work reveals that GcsR is the founding member of a novel class of TyrR-like EBPs that likely regulate glycine metabolism in Pseudomonadales. Glycine serves as a major source of single carbon units for biochemical reactions within bacterial cells. Utilization of glycine is tightly regulated and revolves around a key group of proteins known as the glycine cleavage system (GCS). Our lab previously identified the transcriptional regulator GcsR (PA2449) as being required for catabolism of glycine in the opportunistic pathogen Pseudomonas aeruginosa PAO1. In an effort to clarify and have an overall better understanding of the role of GcsR in glycine metabolism, a combination of transcriptome sequencing and electrophoretic mobility shift assays was used to identify target genes of this transcriptional regulator. It was found that GcsR binds to an 18-bp consensus sequence (TGTAACG-N4-CGTTCCG) upstream of the gcs2 operon, consisting of the gcvH2, gcvP2, glyA2, sdaA, and gcvT2 genes. The proteins encoded by these genes, namely, the GCS (GcvH2-GcvP2-GcvT2), serine hydroxymethyltransferase (GlyA2), and serine dehydratase (SdaA), form a metabolic pathway for the conversion of glycine into pyruvate, which can enter the central metabolism. GcsR activates transcription of the gcs2 operon in response to glycine. Interestingly, GcsR belongs to a family of transcriptional regulators known as TyrR-like enhancer-binding proteins (EBPs). Until this study, TyrR-like EBPs were only known to function in regulating aromatic amino acid metabolism. GcsR is the founding member of a new class of TyrR-like EBPs that function in the regulation of glycine metabolism. Indeed, homologs of GcsR and its target genes are present in almost all sequenced genomes of the Pseudomonadales order, suggesting that this genetic regulatory mechanism is a common theme for pseudomonads. IMPORTANCE Glycine is required for various cellular functions, including cell wall synthesis, protein synthesis, and the biosynthesis of several important metabolites. Regulating levels of glycine metabolism allows P. aeruginosa to maintain the metabolic flux of glycine through several pathways, including the metabolism of glycine to produce other amino acids, entry into the trichloroacetic acid cycle, and the production of virulence factors such as hydrogen cyanide. In this study, we characterized GcsR, a transcriptional regulator that activates the expression of genes involved in P. aeruginosa PAO1 glycine metabolism. Our work reveals that GcsR is the founding member of a novel class of TyrR-like EBPs that likely regulate glycine metabolism in Pseudomonadales.
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Saurav K, Burgsdorf I, Teta R, Esposito G, Bar-Shalom R, Costantino V, Steindler L. Isolation of MarineParacoccussp. Ss63 from the SpongeSarcotragussp. and Characterization of its Quorum-Sensing Chemical-Signaling Molecules by LC-MS/MS Analysis. Isr J Chem 2016. [DOI: 10.1002/ijch.201600003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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135
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Shen Q, Gao J, Liu J, Liu S, Liu Z, Wang Y, Guo B, Zhuang X, Zhuang G. A New Acyl-homoserine Lactone Molecule Generated by Nitrobacter winogradskyi. Sci Rep 2016; 6:22903. [PMID: 26965192 PMCID: PMC4786786 DOI: 10.1038/srep22903] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 02/24/2016] [Indexed: 11/09/2022] Open
Abstract
It is crucial to reveal the regulatory mechanism of nitrification to understand nitrogen conversion in agricultural systems and wastewater treatment. In this study, the nwiI gene of Nitrobacter winogradskyi was confirmed to be a homoserine lactone synthase by heterologous expression in Escherichia coli that synthesized several acyl-homoserine lactone signals with 7 to 11 carbon acyl groups. A novel signal, 7, 8-trans-N-(decanoyl) homoserine lactone (C10:1-HSL), was identified in both N. winogradskyi and the recombined E. coli. Furthermore, this novel signal also triggered variances in the nitrification rate and the level of transcripts for the genes involved in the nitrification process. These results indicate that quorum sensing may have a potential role in regulating nitrogen metabolism.
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Affiliation(s)
- Qiuxuan Shen
- CAS Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Jie Gao
- CAS Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Jun Liu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Shuangjiang Liu
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Zijun Liu
- CAS Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Yinghuan Wang
- CAS Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Baoyuan Guo
- CAS Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Xuliang Zhuang
- CAS Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Guoqiang Zhuang
- CAS Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
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136
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Chen Y, Kim JK, Hirning AJ, Josić K, Bennett MR. SYNTHETIC BIOLOGY. Emergent genetic oscillations in a synthetic microbial consortium. Science 2016; 349:986-9. [PMID: 26315440 DOI: 10.1126/science.aaa3794] [Citation(s) in RCA: 172] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
A challenge of synthetic biology is the creation of cooperative microbial systems that exhibit population-level behaviors. Such systems use cellular signaling mechanisms to regulate gene expression across multiple cell types. We describe the construction of a synthetic microbial consortium consisting of two distinct cell types—an "activator" strain and a "repressor" strain. These strains produced two orthogonal cell-signaling molecules that regulate gene expression within a synthetic circuit spanning both strains. The two strains generated emergent, population-level oscillations only when cultured together. Certain network topologies of the two-strain circuit were better at maintaining robust oscillations than others. The ability to program population-level dynamics through the genetic engineering of multiple cooperative strains points the way toward engineering complex synthetic tissues and organs with multiple cell types.
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Affiliation(s)
- Ye Chen
- Department of Biosciences, Rice University, Houston, TX 77005, USA
| | - Jae Kyoung Kim
- Department of Mathematical Sciences, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Korea. Mathematical Biosciences Institute, The Ohio State University, Columbus, OH 43210, USA
| | - Andrew J Hirning
- Department of Biosciences, Rice University, Houston, TX 77005, USA
| | - Krešimir Josić
- Department of Mathematics, University of Houston, Houston, TX 77204, USA. Department of Biology and Biochemistry, University of Houston, Houston, TX 77204, USA
| | - Matthew R Bennett
- Department of Biosciences, Rice University, Houston, TX 77005, USA. Institute of Biosciences and Bioengineering, Rice University, Houston, TX 77005, USA.
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Wagner S, Sommer R, Hinsberger S, Lu C, Hartmann RW, Empting M, Titz A. Novel Strategies for the Treatment of Pseudomonas aeruginosa Infections. J Med Chem 2016; 59:5929-69. [DOI: 10.1021/acs.jmedchem.5b01698] [Citation(s) in RCA: 176] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Stefanie Wagner
- Chemical
Biology of Carbohydrates, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), D-66123 Saarbrücken, Germany
- Deutsches Zentrum für Infektionsforschung (DZIF), 30625 Standort Hannover-Braunschweig, Germany
| | - Roman Sommer
- Chemical
Biology of Carbohydrates, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), D-66123 Saarbrücken, Germany
- Deutsches Zentrum für Infektionsforschung (DZIF), 30625 Standort Hannover-Braunschweig, Germany
| | - Stefan Hinsberger
- Deutsches Zentrum für Infektionsforschung (DZIF), 30625 Standort Hannover-Braunschweig, Germany
- Drug
Design and Optimization, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), D-66123 Saarbrücken, Germany
| | - Cenbin Lu
- Deutsches Zentrum für Infektionsforschung (DZIF), 30625 Standort Hannover-Braunschweig, Germany
- Drug
Design and Optimization, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), D-66123 Saarbrücken, Germany
| | - Rolf W. Hartmann
- Deutsches Zentrum für Infektionsforschung (DZIF), 30625 Standort Hannover-Braunschweig, Germany
- Drug
Design and Optimization, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), D-66123 Saarbrücken, Germany
| | - Martin Empting
- Deutsches Zentrum für Infektionsforschung (DZIF), 30625 Standort Hannover-Braunschweig, Germany
- Drug
Design and Optimization, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), D-66123 Saarbrücken, Germany
| | - Alexander Titz
- Chemical
Biology of Carbohydrates, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), D-66123 Saarbrücken, Germany
- Deutsches Zentrum für Infektionsforschung (DZIF), 30625 Standort Hannover-Braunschweig, Germany
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Aybey A, Demirkan E. Inhibition of quorum sensing-controlled virulence factors in Pseudomonas aeruginosa by human serum paraoxonase. J Med Microbiol 2016; 65:105-113. [DOI: 10.1099/jmm.0.000206] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Affiliation(s)
- Aynur Aybey
- Department of Biology, Faculty of Arts and Science, Uludag University, 16059, Bursa, Turkey
| | - Elif Demirkan
- Department of Biology, Faculty of Arts and Science, Uludag University, 16059, Bursa, Turkey
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139
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Kang SY, Lee JK, Jang JH, Hwang BY, Hong YS. Production of phenylacetyl-homoserine lactone analogs by artificial biosynthetic pathway in Escherichia coli. Microb Cell Fact 2015; 14:191. [PMID: 26608135 PMCID: PMC4659178 DOI: 10.1186/s12934-015-0379-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Accepted: 11/06/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Quorum sensing (QS) networks are more commonly known as acyl homoserine lactone (HSL) networks. Recently, p-coumaroyl-HSL has been found in a photosynthetic bacterium. p-coumaroyl-HSL is derived from a lignin monomer, p-coumaric acid, rather than a fatty acyl group. The p-coumaroyl-HSL may serve an ecological role in diverse QS pathways between p-coumaroyl-HSL producing bacteria and specific plants. Interference with QS has been regarded as a novel way to control bacterial infections. Heterologous production of the QS molecule, p-coumaroyl-HSL, could provide a sustainable and controlled means for its large-scale production, in contrast to the restricted feedback regulation and extremely low productivity of natural producers. RESULTS We developed an artificial biosynthetic process for phenylacetyl-homoserine lactone analogs, including cinnamoyl-HSL, p-coumaroyl-HSL, caffeoyl-HSL, and feruloyl-HSL, using a bioconversion method via E. coli (CB1) in the co-expression of the codon-optimized LuxI-type synthase (RpaI) and p-coumaroyl-CoA ligase (4CL2nt). In addition to this, we show the de novo production of p-coumaroyl-HSL in heterologous host E. coli (DN1) and tyrosine overproducing E. coli (DN2), containing the rpaI gene in addition to p-coumaroyl-CoA biosynthetic genes. The yields for p-coumaroyl-HSL reached 93.4 ± 0.6 and 142.5 ± 1.0 mg/L in the S-adenosyl-L-methionine and L-methionine feeding culture in the DN2 strain, respectively. CONCLUSIONS This is the first report of a de novo biosynthesis in a heterologous host yielding a QS molecule, p-coumaroyl-HSL from a glucose medium using a single vector system combining p-coumaroyl-CoA biosynthetic genes and the LuxI-type synthase gene.
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Affiliation(s)
- Sun-Young Kang
- Chemical Biology Research Center, Korea Research Institute of Bioscience and Biotechnology, 30 Yeongudanji-ro, Ochang-eup, Chungbuk, 363-883, Republic of Korea.
- Department of Pharmacy Graduate School, Chungbuk National University, Cheongju, 361-763, Republic of Korea.
| | - Jae Kyoung Lee
- Chemical Biology Research Center, Korea Research Institute of Bioscience and Biotechnology, 30 Yeongudanji-ro, Ochang-eup, Chungbuk, 363-883, Republic of Korea.
- Department of Pharmacy Graduate School, Chungbuk National University, Cheongju, 361-763, Republic of Korea.
| | - Jae-Hyuk Jang
- Chemical Biology Research Center, Korea Research Institute of Bioscience and Biotechnology, 30 Yeongudanji-ro, Ochang-eup, Chungbuk, 363-883, Republic of Korea.
| | - Bang Yeon Hwang
- Department of Pharmacy Graduate School, Chungbuk National University, Cheongju, 361-763, Republic of Korea.
| | - Young-Soo Hong
- Chemical Biology Research Center, Korea Research Institute of Bioscience and Biotechnology, 30 Yeongudanji-ro, Ochang-eup, Chungbuk, 363-883, Republic of Korea.
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140
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Liu YC, Chan KG, Chang CY. Modulation of Host Biology by Pseudomonas aeruginosa Quorum Sensing Signal Molecules: Messengers or Traitors. Front Microbiol 2015; 6:1226. [PMID: 26617576 PMCID: PMC4637427 DOI: 10.3389/fmicb.2015.01226] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 10/20/2015] [Indexed: 12/21/2022] Open
Abstract
Bacterial cells sense their population density and respond accordingly by producing various signal molecules to the surrounding environments thereby trigger a plethora of gene expression. This regulatory pathway is termed quorum sensing (QS). Plenty of bacterial virulence factors are controlled by QS or QS-mediated regulatory systems and QS signal molecules (QSSMs) play crucial roles in bacterial signaling transduction. Moreover, bacterial QSSMs were shown to interfere with host cell signaling and modulate host immune responses. QSSMs not only regulate the expression of bacterial virulence factors but themselves act in the modulation of host biology that can be potential therapeutic targets.
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Affiliation(s)
- Yi-Chia Liu
- Division of Molecular Microbiology, School of Life Sciences, University of Dundee Dundee, UK
| | - Kok-Gan Chan
- Division of Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Science, University of Malaya Kuala Lumpur, Malaysia
| | - Chien-Yi Chang
- Centre for Bacterial Cell Biology, Medical School, Newcastle University Newcastle upon Tyne, UK ; Interdisciplinary Computing and Complex BioSystems (ICOS) Research Group, School of Computing Science, Newcastle University Newcastle upon Tyne, UK
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141
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Chan KG, Liu YC, Chang CY. Inhibiting N-acyl-homoserine lactone synthesis and quenching Pseudomonas quinolone quorum sensing to attenuate virulence. Front Microbiol 2015; 6:1173. [PMID: 26539190 PMCID: PMC4609879 DOI: 10.3389/fmicb.2015.01173] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 10/09/2015] [Indexed: 01/27/2023] Open
Abstract
Bacteria sense their own population size, tune the expression of responding genes, and behave accordingly to environmental stimuli by secreting signaling molecules. This phenomenon is termed as quorum sensing (QS). By exogenously manipulating the signal transduction bacterial population behaviors could be controlled, which may be done through quorum quenching (QQ). QS related regulatory networks have been proven their involvement in regulating many virulence determinants in pathogenic bacteria in the course of infections. Interfering with QS signaling system could be a novel strategy against bacterial infections and therefore requires more understanding of their fundamental mechanisms. Here we review the development of studies specifically on the inhibition of production of N-acyl-homoserine lactone (AHL), a common proteobacterial QS signal. The opportunistic pathogen, Pseudomonas aeruginosa, equips the alkylquinolone (AQ)-mediated QS which also plays crucial roles in its pathogenicity. The studies in QQ targeting on AQ are also discussed.
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Affiliation(s)
- Kok-Gan Chan
- Division of Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Science, University of Malaya Kuala Lumpur, Malaysia
| | - Yi-Chia Liu
- Division of Molecular Microbiology, School of Life Sciences, University of Dundee Dundee, UK
| | - Chien-Yi Chang
- Centre for Bacterial Cell Biology, Medical School, Newcastle University Newcastle upon Tyne, UK ; Interdisciplinary Computing and Complex BioSystems Research Group, School of Computing Science, Newcastle University Newcastle upon Tyne, UK
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142
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Shin D, Frane ND, Brecht RM, Keeler J, Nagarajan R. A Comparative Analysis of Acyl-Homoserine Lactone Synthase Assays. Chembiochem 2015; 16:2651-9. [PMID: 26456773 DOI: 10.1002/cbic.201500387] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Indexed: 11/10/2022]
Abstract
Quorum sensing is cell-to-cell communication that allows bacteria to coordinate attacks on their hosts by inducing virulent gene expression, biofilm production, and other cellular functions, including antibiotic resistance. AHL synthase enzymes synthesize N-acyl-l-homoserine lactones, commonly referred to as autoinducers, to facilitate quorum sensing in Gram-negative bacteria. Studying the synthases, however, has proven to be a difficult road. Two assays, including a radiolabeled assay and a colorimetric (DCPIP) assay are well-documented in literature to study AHL synthases. In this paper, we describe additional methods that include an HPLC-based, C-S bond cleavage and coupled assays to investigate this class of enzymes. In addition, we compare and contrast each assay for both acyl-CoA- and acyl-ACP-utilizing synthases. The expanded toolkit described in this study should facilitate mechanistic studies on quorum sensing signal synthases and expedite discovery of antivirulent compounds.
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Affiliation(s)
- Daniel Shin
- Department of Chemistry and Biochemistry, Boise State University, 1910 University Drive, Boise, ID, 83725, USA
| | - Nicole D Frane
- Department of Chemistry and Biochemistry, Boise State University, 1910 University Drive, Boise, ID, 83725, USA
| | - Ryan M Brecht
- Department of Chemistry and Biochemistry, Boise State University, 1910 University Drive, Boise, ID, 83725, USA.,Department of Molecular Biophysics and Biochemistry, Yale University, 260 Whitney Avenue, PO Box 208114, New Haven, CT, 06520-8114, USA
| | - Jesse Keeler
- Department of Chemistry, Northwest Nazarene University, Nampa, ID, 83686, USA.,Loma Linda School of Medicine, Coleman Pavilion, 11175 Campus Street, Loma Linda, CA, 92350, USA
| | - Rajesh Nagarajan
- Department of Chemistry and Biochemistry, Boise State University, 1910 University Drive, Boise, ID, 83725, USA.
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143
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Grandclément C, Tannières M, Moréra S, Dessaux Y, Faure D. Quorum quenching: role in nature and applied developments. FEMS Microbiol Rev 2015; 40:86-116. [PMID: 26432822 DOI: 10.1093/femsre/fuv038] [Citation(s) in RCA: 356] [Impact Index Per Article: 39.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/21/2015] [Indexed: 12/11/2022] Open
Abstract
Quorum sensing (QS) refers to the capacity of bacteria to monitor their population density and regulate gene expression accordingly: the QS-regulated processes deal with multicellular behaviors (e.g. growth and development of biofilm), horizontal gene transfer and host-microbe (symbiosis and pathogenesis) and microbe-microbe interactions. QS signaling requires the synthesis, exchange and perception of bacterial compounds, called autoinducers or QS signals (e.g. N-acylhomoserine lactones). The disruption of QS signaling, also termed quorum quenching (QQ), encompasses very diverse phenomena and mechanisms which are presented and discussed in this review. First, we surveyed the QS-signal diversity and QS-associated responses for a better understanding of the targets of the QQ phenomena that organisms have naturally evolved and are currently actively investigated in applied perspectives. Next the mechanisms, targets and molecular actors associated with QS interference are presented, with a special emphasis on the description of natural QQ enzymes and chemicals acting as QS inhibitors. Selected QQ paradigms are detailed to exemplify the mechanisms and biological roles of QS inhibition in microbe-microbe and host-microbe interactions. Finally, some QQ strategies are presented as promising tools in different fields such as medicine, aquaculture, crop production and anti-biofouling area.
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Affiliation(s)
- Catherine Grandclément
- Institut for Integrative Biology of the Cell, Department of Microbiology, CNRS CEA Paris-Sud University, Saclay Plant Sciences, Avenue de la Terrasse, 91198 Gif-sur-Yvette cedex, France
| | - Mélanie Tannières
- Institut for Integrative Biology of the Cell, Department of Microbiology, CNRS CEA Paris-Sud University, Saclay Plant Sciences, Avenue de la Terrasse, 91198 Gif-sur-Yvette cedex, France
| | - Solange Moréra
- Institut for Integrative Biology of the Cell, Department of Structural Biology, CNRS CEA Paris-Sud University, Avenue de la Terrasse, 91198 Gif-sur-Yvette cedex, France
| | - Yves Dessaux
- Institut for Integrative Biology of the Cell, Department of Microbiology, CNRS CEA Paris-Sud University, Saclay Plant Sciences, Avenue de la Terrasse, 91198 Gif-sur-Yvette cedex, France
| | - Denis Faure
- Institut for Integrative Biology of the Cell, Department of Microbiology, CNRS CEA Paris-Sud University, Saclay Plant Sciences, Avenue de la Terrasse, 91198 Gif-sur-Yvette cedex, France
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Holm A, Karlsson T, Vikström E. Pseudomonas aeruginosa lasI/rhlI quorum sensing genes promote phagocytosis and aquaporin 9 redistribution to the leading and trailing regions in macrophages. Front Microbiol 2015; 6:915. [PMID: 26388857 PMCID: PMC4558532 DOI: 10.3389/fmicb.2015.00915] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 08/21/2015] [Indexed: 12/11/2022] Open
Abstract
Pseudomonas aeruginosa controls production of its multiple virulence factors and biofilm development via the quorum sensing (QS) system. QS signals also interact with and affect the behavior of eukaryotic cells. Host water homeostasis and aquaporins (AQP) are essential during pathological conditions since they interfere with the cell cytoskeleton and signaling, and hereby affect cell morphology and functions. We investigated the contribution of P. aeruginosa QS genes lasI/rhlI to phagocytosis, cell morphology, AQP9 expression, and distribution in human macrophages, using immunoblotting, confocal, and nanoscale imaging. Wild type P. aeruginosa with a functional QS system was a more attractive prey for macrophages than the lasI/rhlI mutant lacking the production of QS molecules, 3O-C12-HSL, and C4-HSL, and associated virulence factors. The P. aeruginosa infections resulted in elevated AQP9 expression and relocalization to the leading and trailing regions in macrophages, increased cell area and length; bacteria with a functional QS system lasI/rhlI achieved stronger responses. We present evidence for a new role of water fluxes via AQP9 during bacteria–macrophage interaction and for the QS system as an important stimulus in this process. These novel events in the interplay between P. aeruginosa and macrophages may influence on the outcome of infection, inflammation, and development of disease.
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Affiliation(s)
- Angelika Holm
- Department of Clinical and Experimental Medicine, Faculty of Medicine and Health Sciences, Linköping University Linköping, Sweden
| | - Thommie Karlsson
- Department of Clinical and Experimental Medicine, Faculty of Medicine and Health Sciences, Linköping University Linköping, Sweden
| | - Elena Vikström
- Department of Clinical and Experimental Medicine, Faculty of Medicine and Health Sciences, Linköping University Linköping, Sweden
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145
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Effect of Cinnamon Oil on Quorum Sensing-Controlled Virulence Factors and Biofilm Formation in Pseudomonas aeruginosa. PLoS One 2015; 10:e0135495. [PMID: 26263486 PMCID: PMC4532483 DOI: 10.1371/journal.pone.0135495] [Citation(s) in RCA: 86] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Accepted: 07/22/2015] [Indexed: 11/19/2022] Open
Abstract
Quorum sensing (QS) is a system of stimuli and responses in bacterial cells governed by their population density, through which they regulate genes that control virulence factors and biofilm formation. Despite considerable research on QS and the discovery of new antibiotics, QS-controlled biofilm formation by microorganisms in clinical settings has remained a problem because of nascent drug resistance, which requires screening of diverse compounds for anti-QS activities. Cinnamon is a dietary phytochemical that is traditionally used to remedy digestive problems and assorted contagions, which suggests that cinnamon might contain chemicals that can hinder the QS process. To test this hypothesis, the anti-QS activity of cinnamon oil against P. aeruginosa was tested, measured by the inhibition of biofilm formation and other QS-associated phenomena, including virulence factors such as pyocyanin, rhamnolipid, protease, alginate production, and swarming activity. To this end, multiple microscopy analyses, including light, scanning electron and confocal microscopy, revealed the ability of cinnamon oil to inhibit P. aeruginosa PAO1 biofilms and their accompanying extracellular polymeric substances. This work is the first to demonstrate that cinnamon oil can influence various QS-based phenomena in P. aeruginosa PAO1, including biofilm formation.
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146
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Bordoy AE, Chatterjee A. Cis-Antisense Transcription Gives Rise to Tunable Genetic Switch Behavior: A Mathematical Modeling Approach. PLoS One 2015. [PMID: 26222133 PMCID: PMC4519249 DOI: 10.1371/journal.pone.0133873] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Antisense transcription has been extensively recognized as a regulatory mechanism for gene expression across all kingdoms of life. Despite the broad importance and extensive experimental determination of cis-antisense transcription, relatively little is known about its role in controlling cellular switching responses. Growing evidence suggests the presence of non-coding cis-antisense RNAs that regulate gene expression via antisense interaction. Recent studies also indicate the role of transcriptional interference in regulating expression of neighboring genes due to traffic of RNA polymerases from adjacent promoter regions. Previous models investigate these mechanisms independently, however, little is understood about how cells utilize coupling of these mechanisms in advantageous ways that could also be used to design novel synthetic genetic devices. Here, we present a mathematical modeling framework for antisense transcription that combines the effects of both transcriptional interference and cis-antisense regulation. We demonstrate the tunability of transcriptional interference through various parameters, and that coupling of transcriptional interference with cis-antisense RNA interaction gives rise to hypersensitive switches in expression of both antisense genes. When implementing additional positive and negative feed-back loops from proteins encoded by these genes, the system response acquires a bistable behavior. Our model shows that combining these multiple-levels of regulation allows fine-tuning of system parameters to give rise to a highly tunable output, ranging from a simple-first order response to biologically complex higher-order response such as tunable bistable switch. We identify important parameters affecting the cellular switch response in order to provide the design principles for tunable gene expression using antisense transcription. This presents an important insight into functional role of antisense transcription and its importance towards design of synthetic biological switches.
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Affiliation(s)
- Antoni E. Bordoy
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, CO, United States of America
| | - Anushree Chatterjee
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, CO, United States of America
- BioFrontiers institute, University of Colorado Boulder, Boulder, CO, United States of America
- * E-mail:
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147
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Yang C, Chowdhury MAK, Huo Y, Gong J. Phytogenic compounds as alternatives to in-feed antibiotics: potentials and challenges in application. Pathogens 2015; 4:137-56. [PMID: 25806623 PMCID: PMC4384076 DOI: 10.3390/pathogens4010137] [Citation(s) in RCA: 154] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Revised: 03/18/2015] [Accepted: 03/19/2015] [Indexed: 12/14/2022] Open
Abstract
This article summarizes current experimental knowledge on the efficacy, possible mechanisms and feasibility in the application of phytogenic products as feed additives for food-producing animals. Phytogenic compounds comprise a wide range of plant-derived natural bioactive compounds and essential oils are a major group. Numerous studies have demonstrated that phytogenic compounds have a variety of functions, including antimicrobial/antiviral, antioxidative and anti-inflammation effects and improvement in the palatability of feed and gut development/health. However, the mechanisms underlying their functions are still largely unclear. In the past, there has been a lack of consistency in the results from both laboratory and field studies, largely due to the varied composition of products, dosages, purities and growing conditions of animals used. The minimal inhibitory concentration (MIC) of phytogenic compounds required for controlling enteric pathogens may not guarantee the best feed intake, balanced immunity of animals and cost-effectiveness in animal production. The lipophilic nature of photogenic compounds also presents a challenge in effective delivery to the animal gut and this can partially be resolved by microencapsulation and combination with other compounds (synergistic effect). Interestingly, the effects of photogenic compounds on anti-inflammation, gut chemosensing and possible disruption of bacterial quorum sensing could explain a certain number of studies with different animal species for the better production performance of animals that have received phytogenic feed additives. It is obvious that phytogenic compounds have good potential as an alternative to antibiotics in feed for food animal production and the combination of different phytogenic compounds appears to be an approach to improve the efficacy and safety of phytogenic compounds in the application. It is our expectation that the recent development of high-throughput and "omics" technologies can significantly advance the studies on the mechanisms underlying phytogenic compounds' functions and, therefore, guide the effective use of the compounds.
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Affiliation(s)
- Chengbo Yang
- Jefo Nutrition Inc., 5020 Jefo Avenue, C.P. 325, Saint-Hyacinthe, QC J2S 7B6, Canada.
| | - M A Kabir Chowdhury
- Jefo Nutrition Inc., 5020 Jefo Avenue, C.P. 325, Saint-Hyacinthe, QC J2S 7B6, Canada.
| | - Yongqing Huo
- Hubei Key Laboratory of Animal Nutrition and Feed Science, Wuhan Polytechnic University, Wuhan 430023, China.
| | - Joshua Gong
- Guelph Food Research Centre, Agriculture and Agri-Food Canada, 93 Stone Road West, Guelph, ON N1G 5C9, Canada.
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148
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The dependence of quorum sensing in Serratia marcescens JG on the transcription of luxS gene. Arch Microbiol 2015; 197:715-21. [PMID: 25731898 DOI: 10.1007/s00203-015-1099-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2014] [Revised: 12/16/2014] [Accepted: 02/26/2015] [Indexed: 12/25/2022]
Abstract
Bacteria communicate with one another using chemical signal molecules. This phenomenon termed quorum sensing enables the bacteria to monitor the environment for other bacteria and to alter behavior on a population-wide scale in response to cell density. Serratia marcescens JG, a quorum sensing bacterium, can secrete a furanosyl borate diester autoinducer (AI-2) in the exponential phase of growth. In this study, to further investigate the regulation of AI-2 production in S. marcescens JG, the pfs and luxS promoter fusions to an operon luxCDABE reporter were constructed in a low-copy-number vector pBR322K, which allows an examination of transcription of the genes in the pathway for signal synthesis. The results show that the luxS expression is constitutive, and the transcription of luxS is tightly correlated with AI-2 production in S. marcescens JG because the peaks of AI-2 production and transcriptional level of luxS appear at the same time point. The close relation of the profiles of luxS transcription and AI-2 production was also confirmed with real-time PCR technology. These results support the hypothesis that the quorum sensing in S. marcescens JG is luxS dependent.
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149
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Abstract
Resistance of important bacterial pathogens to common antimicrobial therapies and the emergence of multidrug-resistant bacteria are increasing at an alarming rate and constitute one of our greatest challenges in the combat of bacterial infection and accompanied diseases. The current shortage of effective drugs, lack of successful prevention measures and only a few new antibiotics in the clinical pipeline demand the development of novel treatment options and alternative antimicrobial therapies. Our increasing understanding of bacterial virulence strategies and the induced molecular pathways of the infectious disease provides novel opportunities to target and interfere with crucial pathogenicity factors or virulence-associated traits of the bacteria while bypassing the evolutionary pressure on the bacterium to develop resistance. In the past decade, numerous new bacterial targets for anti-virulence therapies have been identified, and structure-based tailoring of intervention strategies and screening assays for small-molecule inhibitors of such pathways were successfully established. In this chapter, we will take a closer look at the bacterial virulence-related factors and processes that present promising targets for anti-virulence therapies, recently discovered inhibitory substances and their promises and discuss the challenges, and problems that have to be faced.
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150
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Chang CY, Krishnan T, Wang H, Chen Y, Yin WF, Chong YM, Tan LY, Chong TM, Chan KG. Non-antibiotic quorum sensing inhibitors acting against N-acyl homoserine lactone synthase as druggable target. Sci Rep 2014; 4:7245. [PMID: 25430794 PMCID: PMC4246208 DOI: 10.1038/srep07245] [Citation(s) in RCA: 101] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Accepted: 11/11/2014] [Indexed: 01/07/2023] Open
Abstract
N-acylhomoserine lactone (AHL)-based quorum sensing (QS) is important for the regulation of proteobacterial virulence determinants. Thus, the inhibition of AHL synthases offers non-antibiotics-based therapeutic potentials against QS-mediated bacterial infections. In this work, functional AHL synthases of Pseudomonas aeruginosa LasI and RhlI were heterologously expressed in an AHL-negative Escherichia coli followed by assessments on their AHLs production using AHL biosensors and high resolution liquid chromatography–mass spectrometry (LCMS). These AHL-producing E. coli served as tools for screening AHL synthase inhibitors. Based on a campaign of screening synthetic molecules and natural products using our approach, three strongest inhibitors namely are salicylic acid, tannic acid and trans-cinnamaldehyde have been identified. LCMS analysis further confirmed tannic acid and trans-cinnemaldehyde efficiently inhibited AHL production by RhlI. We further demonstrated the application of trans-cinnemaldehyde inhibiting Rhl QS system regulated pyocyanin production in P. aeruginosa up to 42.06%. Molecular docking analysis suggested that trans-cinnemaldehyde binds to the LasI and EsaI with known structures mainly interacting with their substrate binding sites. Our data suggested a new class of QS-inhibiting agents from natural products targeting AHL synthase and provided a potential approach for facilitating the discovery of anti-QS signal synthesis as basis of novel anti-infective approach.
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Affiliation(s)
- Chien-Yi Chang
- 1] Interdisciplinary Computing and Complex BioSystems (ICOS) research group, School of Computing Science, Claremont Tower, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK [2] The Centre for Bacterial Cell Biology, Medical School, Newcastle University, Richardson Road, Newcastle upon Tyne, NE2 4AX, UK
| | - Thiba Krishnan
- Division of Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Hao Wang
- School of Pharmacy, Ningxia Medical University, Yinchuan, P. R. China
| | - Ye Chen
- School of Life Sciences, Centre for Biomolecular Sciences, University of Nottingham, Nottingham NG7 2RD, UK
| | - Wai-Fong Yin
- Division of Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Yee-Meng Chong
- Division of Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Li Ying Tan
- Division of Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Teik Min Chong
- Division of Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Kok-Gan Chan
- Division of Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia
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