151
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Cai S, Shen Y, Zou Y, Sun P, Wei W, Zhao J, Zhang C. Engineering highly sensitive whole-cell mercury biosensors based on positive feedback loops from quorum-sensing systems. Analyst 2018; 143:630-634. [PMID: 29271434 DOI: 10.1039/c7an00587c] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Mercury contamination represents a global threat. A simple, sensitive, and rapid means of detecting trace mercury is urgently needed. Herein, we have developed a series of mercury biosensors by combining quorum sensing-based positive feedback systems with a mercury-specific operon, merR. Our results have demonstrated that the sensitivity and fluorescence intensity of the engineered E. coli cells were greatly improved thanks to the positive feedback system. In addition, by fitting the fluorescence signals to the classic Hill equation, we discovered that the responses of the engineered E. coli cells were close to ultrasensitive curves. Our work highlights quorum-sensing systems as a powerful tool in biosensor designs.
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Affiliation(s)
- Sheng Cai
- State Key Laboratory of Coordination Chemistry, Institute of Chemistry and BioMedical Sciences, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Chemistry for Life Sciences, Nanjing University, Nanjing 210093, China.
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152
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The role of LasR active site amino acids in the interaction with the Acyl Homoserine Lactones (AHLs) analogues: A computational study. J Mol Graph Model 2018; 86:113-124. [PMID: 30352386 DOI: 10.1016/j.jmgm.2018.10.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 09/14/2018] [Accepted: 10/13/2018] [Indexed: 01/29/2023]
Abstract
The present work combines molecular docking calculations, 3D-QSAR, molecular dynamics simulations and free binding energy calculations (MM/PBSA and MM/GBSA) in a set of 28 structural analogues of acyl homoserine lactones with Quorum Sensing antagonist activity. The aim of this work is to understand how ligand binds and is affected by the molecular microenvironment in the active site of the LasR receptor for pseudomonas aeruginosa. We also study the stability of the interaction to find key structural characteristics that explain the antagonist activities of this set of ligands. This information is relevant for the rational modification or design of molecules and their identification as powerful LasR modulators. The analysis of molecular docking simulations shows that the 28 analogues have a similar binding mode compared to the native ligand. The carbonyl groups belonging to the lactone ring and the amide group of the acyl chain are oriented towards the amino acids forming hydrogen bond like interactions. The difference in antagonist activity is due to location and orientation of the LasR side chains within the hydrophobic pocket in its binding site. Additionally, we carried out molecular dynamics simulations to understand the conformational changes in the ligand-receptor interaction and the stability of each complex. Results show a direct relationship among the interaction energies of the ligands and the activities as an antagonist of the LasR receptor.
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153
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Laing B, Barnett MPG, Marlow G, Nasef NA, Ferguson LR. An update on the role of gut microbiota in chronic inflammatory diseases, and potential therapeutic targets. Expert Rev Gastroenterol Hepatol 2018; 12:969-983. [PMID: 30052094 DOI: 10.1080/17474124.2018.1505497] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The human microbiome plays a critical role in human health, having metabolic, protective, and trophic functions, depending upon its' exact composition. This composition is affected by a number of factors, including the genetic background of the individual, early life factors (including method of birth, length of breastfeeding) and nature of the diet and other environmental exposures (including cigarette smoking) and general life habits. It plays a key role in the control of inflammation, and in turn, its' composition is significantly influenced by inflammation. Areas covered: We consider metabolic, protective, and trophic functions of the microbiome and influences through the lifespan from post-partum effects, to diet later in life in healthy older adults, the effects of aging on both its' composition, and influence on health and potential therapeutic targets that may have anti-inflammatory effects. Expert commentary: The future will see the growth of more effective therapies targeting the microbiome particularly with respect to the use of specific nutrients and diets personalized to the individual.
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Affiliation(s)
- Bobbi Laing
- a Discipline of Nutrition and Dietetics, Faculty of Medical Health Sciences , The University of Auckland , Auckland , New Zealand.,b School of Nursing, Faculty of Medical and Health Sciences , The University of Auckland , Auckland , New Zealand
| | - Matthew P G Barnett
- c Food Nutrition & Health Team, Food & Bio-Based Products Group , AgResearch Limited , Palmerston North , New Zealand.,d Liggins Institute , The High-Value Nutrition National Science Challenge , Auckland , New Zealand.,e Riddet Institute , Massey University , Palmerston North , New Zealand
| | - Gareth Marlow
- f Institute of Medical Genetics , Cardiff University , Cardiff , Wales , UK
| | - Noha Ahmed Nasef
- e Riddet Institute , Massey University , Palmerston North , New Zealand.,g College of Health, Massey Institute of Food Science and Technology , Palmerston North , New Zealand
| | - Lynnette R Ferguson
- a Discipline of Nutrition and Dietetics, Faculty of Medical Health Sciences , The University of Auckland , Auckland , New Zealand.,h Auckland Cancer Research Society, Faculty of Medical and Health Sciences, Grafton Campus , The University of Auckland , Auckland , New Zealand
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154
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Preparation and Use of a General Solid-Phase Intermediate to Biomimetic Scaffolds and Peptide Condensations. Molecules 2018; 23:molecules23071762. [PMID: 30021979 PMCID: PMC6100553 DOI: 10.3390/molecules23071762] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2018] [Revised: 07/11/2018] [Accepted: 07/14/2018] [Indexed: 11/18/2022] Open
Abstract
The Distributed Drug Discovery (D3) program develops simple, powerful, and reproducible procedures to enable the distributed synthesis of large numbers of potential drugs for neglected diseases. The synthetic protocols are solid-phase based and inspired by published work. One promising article reported that many biomimetic molecules based on diverse scaffolds with three or more sites of variable substitution can be synthesized in one or two steps from a common key aldehyde intermediate. This intermediate was prepared by the ozonolysis of a precursor functionalized at two variable sites, restricting their presence in the subsequently formed scaffolds to ozone compatible functional groups. To broaden the scope of the groups available at one of these variable sites, we developed a synthetic route to an alternative, orthogonally protected key intermediate that allows the incorporation of ozone sensitive groups after the ozonolysis step. The utility of this orthogonally protected intermediate is demonstrated in the synthesis of several representative biomimetic scaffolds containing ozonolytically labile functional groups. It is compatible with traditional Fmoc peptide chemistry, permitting it to incorporate peptide fragments for use in fragment condensations with peptides containing cysteine at the N-terminus. Overall yields for its synthesis and utilization (as many as 13 steps) indicate good conversions at each step.
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155
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Lv L, Li W, Zheng Z, Li D, Zhang N. Exogenous acyl-homoserine lactones adjust community structures of bacteria and methanogens to ameliorate the performance of anaerobic granular sludge. JOURNAL OF HAZARDOUS MATERIALS 2018; 354:72-80. [PMID: 29729601 DOI: 10.1016/j.jhazmat.2018.04.075] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 04/26/2018] [Accepted: 04/28/2018] [Indexed: 06/08/2023]
Abstract
Quorum sensing (QS) signalling has been extensively studied in single species populations, activated sludge, biofilm and aerobic granular sludge. However, ecological roles of QS in anaerobic granular sludge, particularly in the content of the relationship between QS signalling and microbial community composition and function, have been rarely reported. Herein, five acyl-homoserine lactones (AHLs) molecules were added in the anaerobic granular sludge system for treating traditional Chinese medicine (TCM) wastewater respectively. The results indicated that the introduction of specific AHLs could enhance the abilities of organic matters removal and methanation in anaerobic granular sludge, and meanwhile, exogenous AHLs played an important role to regulate the concentration of EPS. Sequencing analysis indicated that microbial community structures of bacteria and methanogens changed to varying degrees by adding AHLs. This study suggested that exogenous AHLs could play a role in mediating microbial community structure, thereby enhancing the performance of anaerobic granular sludge. The regulatory mechanism of AHLs on community structure was discussed, and a speculative action model was established. Exogenous regulation by selective enhancement of AHLs-mediated QS in anaerobic granular sludge provided an innovative and attractive strategy for strengthening wastewater treatments.
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Affiliation(s)
- Longyi Lv
- School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin, 150090, PR China
| | - Weiguang Li
- State Key Laboratory of Urban Water Resource and Environment, Harbin, 150090, PR China; School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin, 150090, PR China.
| | - Zejia Zheng
- School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin, 150090, PR China
| | - Donghui Li
- School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin, 150090, PR China
| | - Ning Zhang
- School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin, 150090, PR China
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156
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Devi KR, Srinivasan S, Ravi AV. Inhibition of quorum sensing-mediated virulence in Serratia marcescens by Bacillus subtilis R-18. Microb Pathog 2018; 120:166-175. [DOI: 10.1016/j.micpath.2018.04.023] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2017] [Revised: 04/12/2018] [Accepted: 04/12/2018] [Indexed: 10/17/2022]
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157
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Sun Y, He K, Yin Q, Echigo S, Wu G, Guan Y. Determination of quorum-sensing signal substances in water and solid phases of activated sludge systems using liquid chromatography-mass spectrometry. J Environ Sci (China) 2018; 69:85-94. [PMID: 29941272 DOI: 10.1016/j.jes.2017.04.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Revised: 04/18/2017] [Accepted: 04/19/2017] [Indexed: 06/08/2023]
Abstract
The detection of acyl homoserine lactones (AHLs) in activated sludge is essential for clarifying their function in wastewater treatment processes. An LC-MS/MS method was developed for the detection of AHLs in both the aqueous and solid phases of activated sludge. In addition, the effects of proteases and extracellular polymeric substances (EPS) on the detection of AHLs were evaluated by adding protease inhibitors and extracting EPS, respectively. Recoveries of each AHL were improved by adding 50μL of protease inhibitor, and recoveries were also improved from 0 to 56.9% to 24.2%-105.8% by EPS extraction. Applying the developed method to determine the type and concentration of AHLs showed that C4-HSL, C6-HSL, C8-HSL and 3-oxo-C8-HSL were widely detected in a suspended activated sludge system. The dominant AHL was C8-HSL, with a highest concentration of 304.3ng/L. C4-HSL was mainly distributed in the aqueous phase, whereas C6-HSL, C8-HSL and 3-oxo-C8-HSL were preferentially distributed in the sludge phase.
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Affiliation(s)
- Yuepeng Sun
- Key Laboratory of Microorganism Application and Risk Control (MARC) of Shenzhen, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, China
| | - Kai He
- Department of Environmental Engineering, Graduate School of Engineering, Kyoto University, Kyoto 615-8540, Japan
| | - Qidong Yin
- Key Laboratory of Microorganism Application and Risk Control (MARC) of Shenzhen, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, China
| | - Shinya Echigo
- Department of Environmental Engineering, Graduate School of Engineering, Kyoto University, Kyoto 615-8540, Japan
| | - Guangxue Wu
- Key Laboratory of Microorganism Application and Risk Control (MARC) of Shenzhen, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, China.
| | - Yuntao Guan
- Key Laboratory of Microorganism Application and Risk Control (MARC) of Shenzhen, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, China
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158
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Two rsaM Homologues Encode Central Regulatory Elements Modulating Quorum Sensing in Burkholderia thailandensis. J Bacteriol 2018; 200:JB.00727-17. [PMID: 29507087 DOI: 10.1128/jb.00727-17] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 02/20/2018] [Indexed: 01/05/2023] Open
Abstract
The bacterium Burkholderia thailandensis possesses three N-acyl-l-homoserine lactone (AHL) quorum sensing (QS) systems designated BtaI1/BtaR1 (QS-1), BtaI2/BtaR2 (QS-2), and BtaI3/BtaR3 (QS-3). These QS systems are associated with the biosynthesis of N-octanoyl-homoserine lactone (C8-HSL), N-3-hydroxy-decanoyl-homoserine lactone (3OHC10-HSL), and N-3-hydroxy-octanoyl-homoserine lactone (3OHC8-HSL), which are produced by the LuxI-type synthases BtaI1, BtaI2, and BtaI3 and modulated by the LuxR-type transcriptional regulators BtaR1, BtaR2, and BtaR3. The btaR1-btaI1 and btaR2-btaI2 gene clusters each carry an additional gene encoding a homologue of the QS repressor RsaM originally identified in the phytopathogen Pseudomonas fuscovaginae and thus here named rsaM1 and rsaM2, respectively. We have characterized the functions of these two conserved rsaM homologues and demonstrated their involvement in the regulation of AHL biosynthesis in B. thailandensis strain E264. We quantified the production of C8-HSL, 3OHC10-HSL, and 3OHC8-HSL by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) in the wild-type strain and in the rsaM1 and rsaM2 mutants, and we monitored btaI1, btaI2, and btaI3 expression using chromosomal mini-CTX-lux transcriptional reporters. The transcription of btaR1, btaR2, and btaR3 was also measured by quantitative reverse transcription-PCR (qRT-PCR). We observed that RsaM1 mainly represses the QS-1 system, whereas RsaM2 principally represses the QS-2 system. We also found that both rsaM1 and rsaM2 are QS controlled and negatively autoregulated. We conclude that RsaM1 and RsaM2 are an integral part of the QS circuitry of B. thailandensis and play a major role in the hierarchical and homeostatic organization of the QS-1, QS-2, and QS-3 systems.IMPORTANCE Quorum sensing (QS) is commonly involved in the coordination of gene transcription associated with the establishment of host-pathogen interactions and acclimatization to the environment. We present the functional characterization of two rsaM homologues in the regulation of the multiple QS systems coexisting in the nonpathogenic bacterium Burkholderia thailandensis, which is widely used as a model system for the study of the human pathogen Burkholderia pseudomallei We found that inactivation of these rsaM homologues, which are clustered with the other QS genes, profoundly affects the QS circuitry of B. thailandensis We conclude that they constitute essential regulatory components of the QS modulatory network and provide additional layers of regulation to modulate the transcription of QS-controlled genes, particularly those linked to environmental adaptation.
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159
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Lee K, Pletcher SD, Lynch SV, Goldberg AN, Cope EK. Heterogeneity of Microbiota Dysbiosis in Chronic Rhinosinusitis: Potential Clinical Implications and Microbial Community Mechanisms Contributing to Sinonasal Inflammation. Front Cell Infect Microbiol 2018; 8:168. [PMID: 29876323 PMCID: PMC5974464 DOI: 10.3389/fcimb.2018.00168] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Accepted: 05/02/2018] [Indexed: 12/27/2022] Open
Abstract
Recent studies leveraging next-generation sequencing and functional approaches to understand the human microbiota have demonstrated the presence of diverse, niche-specific microbial communities at nearly every mucosal surface. These microbes contribute to the development and function of physiologic and immunological features that are key to host health status. Not surprisingly, several chronic inflammatory diseases have been attributed to dysbiosis of microbiota composition or function, including chronic rhinosinusitis (CRS). CRS is a heterogeneous disease characterized by inflammation of the sinonasal cavity and mucosal microbiota dysbiosis. Inflammatory phenotypes and bacterial community compositions vary considerably across individuals with CRS, complicating current studies that seek to address causality of a dysbiotic microbiome as a driver or initiator of persistent sinonasal inflammation. Murine models have provided some experimental evidence that alterations in local microbial communities and microbially-produced metabolites influence health status. In this perspective, we will discuss the clinical implications of distinct microbial compositions and community-level functions in CRS and how mucosal microbiota relate to the diverse inflammatory endotypes that are frequently observed. We will also describe specific microbial interactions that can deterministically shape the pattern of co-colonizers and the resulting metabolic products that drive or exacerbate host inflammation. These findings are discussed in the context of CRS-associated inflammation and in other chronic inflammatory diseases that share features observed in CRS. An improved understanding of CRS patient stratification offers the opportunity to personalize therapeutic regimens and to design novel treatments aimed at manipulation of the disease-associated microbiota to restore sinus health.
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Affiliation(s)
- Keehoon Lee
- Department of Biological Sciences, Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, AZ, United States
| | - Steven D Pletcher
- Department of Otolaryngology Head and Neck Surgery, University of California, San Francisco, San Francisco, CA, United States
| | - Susan V Lynch
- Division of Medicine, Department of Gastroenterology, University of California, San Francisco, San Francisco, CA, United States
| | - Andrew N Goldberg
- Department of Otolaryngology Head and Neck Surgery, University of California, San Francisco, San Francisco, CA, United States
| | - Emily K Cope
- Department of Biological Sciences, Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, AZ, United States
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160
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Andrea A, Molchanova N, Jenssen H. Antibiofilm Peptides and Peptidomimetics with Focus on Surface Immobilization. Biomolecules 2018; 8:E27. [PMID: 29772735 PMCID: PMC6022873 DOI: 10.3390/biom8020027] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 05/12/2018] [Accepted: 05/14/2018] [Indexed: 12/17/2022] Open
Abstract
Bacterial biofilms pose a major threat to public health, as they are associated with at least two thirds of all infections. They are highly resilient and render conventional antibiotics inefficient. As a part of the innate immune system, antimicrobial peptides have drawn attention within the last decades, as some of them are able to eradicate biofilms at sub-minimum inhibitory concentration (MIC) levels. However, peptides possess a number of disadvantages, such as susceptibility to proteolytic degradation, pH and/or salinity-dependent activity and loss of activity due to binding to serum proteins. Hence, proteolytically stable peptidomimetics were designed to overcome these drawbacks. This paper summarizes the current peptide and peptidomimetic strategies for combating bacteria-associated biofilm infections, both in respect to soluble and surface-functionalized solutions.
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Affiliation(s)
- Athina Andrea
- Department of Science and Environment, Roskilde University, Universitetsvej 1, 4000 Roskilde, Denmark.
| | - Natalia Molchanova
- Department of Science and Environment, Roskilde University, Universitetsvej 1, 4000 Roskilde, Denmark.
| | - Håvard Jenssen
- Department of Science and Environment, Roskilde University, Universitetsvej 1, 4000 Roskilde, Denmark.
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161
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Peng P, Huang H, Ren H, Ma H, Lin Y, Geng J, Xu K, Zhang Y, Ding L. Exogenous N-acyl homoserine lactones facilitate microbial adhesion of high ammonia nitrogen wastewater on biocarrier surfaces. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 624:1013-1022. [PMID: 29929218 DOI: 10.1016/j.scitotenv.2017.12.248] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Revised: 12/17/2017] [Accepted: 12/21/2017] [Indexed: 06/08/2023]
Abstract
Startup of biofilm process triggered by initial adhesion of bacteria is difficult in high ammonia nitrogen wastewater treatment. In this study, the influence of two commonly used N-acyl homoserine lactones (AHLs), N-Hexanoyl-l-homoserine lactone (C6-HSL) and N-Octanoyl-l-homoserine lactone (C8-HSL), on the adhesion of soluble macromolecules and bacteria in four types of high ammonia nitrogen wastewater to surfaces of model biocarriers (i.e. polystyrene, polyamide and polyethylene terephthalate) was investigated by using a quartz crystal microbalance with dissipation (QCM-D) monitoring technology. Results showed that the adhesion was enhanced by the addition of exogenous AHLs and there was more microbial retention attributed by C8-HSL. Greater deposition amount was generally found on PS and better enhanced performances of the adhesion were found on PA surface. Furthermore, viscoelastic film formed under synchronous high-low salinity and organic content and dominant bacteria of real wastewater determined the role of exogenous AHLs. The method of adding moderate amount of exogenous AHLs into bioreactors has important implications for accelerating the startup process treating high ammonia nitrogen wastewater by biofilm process.
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Affiliation(s)
- Pengcheng Peng
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, Jiangsu, PR China
| | - Hui Huang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, Jiangsu, PR China.
| | - Hongqiang Ren
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, Jiangsu, PR China
| | - Haijun Ma
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, Jiangsu, PR China
| | - Yuan Lin
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, Jiangsu, PR China
| | - Jinju Geng
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, Jiangsu, PR China
| | - Ke Xu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, Jiangsu, PR China
| | - Yan Zhang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, Jiangsu, PR China
| | - Lili Ding
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, Jiangsu, PR China
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162
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Boursier ME, Manson DE, Combs JB, Blackwell HE. A comparative study of non-native N-acyl l-homoserine lactone analogs in two Pseudomonas aeruginosa quorum sensing receptors that share a common native ligand yet inversely regulate virulence. Bioorg Med Chem 2018; 26:5336-5342. [PMID: 29793752 DOI: 10.1016/j.bmc.2018.05.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 05/07/2018] [Accepted: 05/13/2018] [Indexed: 10/16/2022]
Abstract
Certain bacteria can coordinate group behaviors via a chemical communication system known as quorum sensing (QS). Gram-negative bacteria typically use N-acyl l-homoserine lactone (AHL) signals and their cognate intracellular LuxR-type receptors for QS. The opportunistic pathogen Pseudomonas aeruginosa has a relatively complex QS circuit in which two of its LuxR-type receptors, LasR and QscR, are activated by the same natural signal, N-(3-oxo)-dodecanoyl l-homoserine lactone. Intriguingly, once active, LasR activates virulence pathways in P. aeruginosa, while activated QscR can inactivate LasR and thus repress virulence. We have a limited understanding of the structural features of AHLs that engender either agonistic activity in both receptors or receptor-selective activity. Compounds with the latter activity profile could prove especially useful tools to tease out the roles of these two receptors in virulence regulation. A small collection of AHL analogs was assembled and screened in cell-based reporter assays for activity in both LasR and QscR. We identified several structural motifs that bias ligand activation towards each of the two receptors. These findings will inform the development of new synthetic ligands for LasR and QscR with improved potencies and selectivities.
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Affiliation(s)
- Michelle E Boursier
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave., Madison, WI 53706, USA
| | - Daniel E Manson
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave., Madison, WI 53706, USA
| | - Joshua B Combs
- 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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163
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Almohaywi B, Taunk A, Wenholz DS, Nizalapur S, Biswas NN, Ho KKK, Rice SA, Iskander G, Black DS, Griffith R, Kumar N. Design and Synthesis of Lactams Derived from Mucochloric and Mucobromic Acids as Pseudomonas aeruginosa Quorum Sensing Inhibitors. Molecules 2018; 23:molecules23051106. [PMID: 29735954 PMCID: PMC6100351 DOI: 10.3390/molecules23051106] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Revised: 05/04/2018] [Accepted: 05/05/2018] [Indexed: 11/24/2022] Open
Abstract
Bacterial infections, particularly hospital-acquired infections caused by Pseudomonas aeruginosa, have become a global threat with a high mortality rate. Gram-negative bacteria including P. aeruginosa employ N-acyl homoserine lactones (AHLs) as chemical signals to regulate the expression of pathogenic phenotypes through a mechanism called quorum sensing (QS). Recently, strategies targeting bacterial behaviour or QS have received great attention due to their ability to disarm rather than kill pathogenic bacteria, which lowers the evolutionary burden on bacteria and the risk of resistance development. In the present study, we report the design and synthesis of N-alkyl- and N-aryl 3,4 dichloro- and 3,4-dibromopyrrole-2-one derivatives through the reductive amination of mucochloric and mucobromic acid with aliphatic and aromatic amines. The quorum sensing inhibition (QSI) activity of the synthesized compounds was determined against a P. aeruginosa MH602 reporter strain. The phenolic compounds exhibited the best activity with 80% and 75% QSI at 250 µM and were comparable in activity to the positive control compound Fu-30. Computational docking studies performed using the LasR receptor protein of P. aeruginosa suggested the importance of hydrogen bonding and hydrophobic interactions for QSI.
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Affiliation(s)
- Basmah Almohaywi
- School of Chemistry, UNSW Australia, Sydney, NSW 2052, Australia.
- School of Pharmacy, King Khalid University, Abha 62529, Saudi Arabia.
| | - Aditi Taunk
- School of Chemistry, UNSW Australia, Sydney, NSW 2052, Australia.
| | - Daniel S Wenholz
- School of Chemistry, UNSW Australia, Sydney, NSW 2052, Australia.
| | | | | | - Kitty K K Ho
- School of Chemistry, UNSW Australia, Sydney, NSW 2052, Australia.
| | - Scott A Rice
- The Singapore Centre of Environmental Life Sciences Engineering, Nanyang Technological University, Singapore 639798, Singapore.
| | - George Iskander
- School of Chemistry, UNSW Australia, Sydney, NSW 2052, Australia.
| | - David StC Black
- School of Chemistry, UNSW Australia, Sydney, NSW 2052, Australia.
| | - Renate Griffith
- School of Medical Science, UNSW Australia, Sydney, NSW 2052, Australia.
| | - Naresh Kumar
- School of Chemistry, UNSW Australia, Sydney, NSW 2052, Australia.
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164
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Kim TH, Lee I, Yeon KM, Kim J. Biocatalytic membrane with acylase stabilized on intact carbon nanotubes for effective antifouling via quorum quenching. J Memb Sci 2018. [DOI: 10.1016/j.memsci.2018.03.020] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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165
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Utari PD, Setroikromo R, Melgert BN, Quax WJ. PvdQ Quorum Quenching Acylase Attenuates Pseudomonas aeruginosa Virulence in a Mouse Model of Pulmonary Infection. Front Cell Infect Microbiol 2018; 8:119. [PMID: 29755959 PMCID: PMC5932173 DOI: 10.3389/fcimb.2018.00119] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 04/03/2018] [Indexed: 01/24/2023] Open
Abstract
Pseudomonas aeruginosa is the predominant pathogen in pulmonary infections associated with cystic fibrosis. Quorum sensing (QS) systems regulate the production of virulence factors and play an important role in the establishment of successful P. aeruginosa infections. Inhibition of the QS system (termed quorum quenching) renders the bacteria avirulent thus serving as an alternative approach in the development of novel antibiotics. Quorum quenching in Gram negative bacteria can be achieved by preventing the accumulation of N-acyl homoserine lactone (AHL) signaling molecule via enzymatic degradation. Previous work by us has shown that PvdQ acylase hydrolyzes AHL signaling molecules irreversibly, thereby inhibiting QS in P. aeruginosa in vitro and in a Caenorhabditis elegans model of P. aeruginosa infection. The aim of the present study is to assess the therapeutic efficacy of intranasally instilled PvdQ acylase in a mouse model of pulmonary P. aeruginosa infection. First, we evaluated the deposition pattern of intranasally administered fluorochrome-tagged PvdQ (PvdQ-VT) in mice at different stages of pulmonary infection by in vivo imaging studies. Following intranasal instillation, PvdQ-VT could be traced in all lung lobes with 42 ± 7.5% of the delivered dose being deposited at 0 h post-bacterial-infection, and 34 ± 5.2% at 72 h post bacterial-infection. We then treated mice with PvdQ during lethal P. aeruginosa pulmonary infection and that resulted in a 5-fold reduction of lung bacterial load and a prolonged survival of the infected animals with the median survival time of 57 hin comparison to 42 h for the PBS-treated group. In a sublethal P. aeruginosa pulmonary infection, PvdQ treatment resulted in less lung inflammation as well as decrease of CXCL2 and TNF-α levels at 24 h post-bacterial-infection by 15 and 20%, respectively. In conclusion, our study has shown therapeutic efficacy of PvdQ acylase as a quorum quenching agent during P. aeruginosa infection.
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Affiliation(s)
- Putri D. Utari
- Department of Chemical and Pharmaceutical Biology, University of Groningen, Groningen, Netherlands
| | - Rita Setroikromo
- Department of Chemical and Pharmaceutical Biology, University of Groningen, Groningen, Netherlands
| | - Barbro N. Melgert
- Department of Pharmacokinetics, Toxicology and Targeting, University of Groningen, Groningen, Netherlands
| | - Wim J. Quax
- Department of Chemical and Pharmaceutical Biology, University of Groningen, Groningen, Netherlands
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McGivney E, Jones KE, Weber B, Valentine AM, VanBriesen JM, Gregory KB. Quorum Sensing Signals Form Complexes with Ag + and Cu 2+ Cations. ACS Chem Biol 2018; 13:894-899. [PMID: 29508988 DOI: 10.1021/acschembio.7b01000] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Quorum sensing (QS) regulates important bacterial behaviors such as virulent protein production and biofilm formation. QS requires that molecular signals are exchanged between cells, extracellularly, where environmental conditions influence signal stability. In this work, we present a novel complexation between metal cations (Ag+ and Cu2+) and a QS autoinducer signal, N-hexanoyl- L-homoserine lactone (HHL). The molecular interactions were investigated using mass spectrometery, attenuated total reflectance-Fourier transform infrared spectroscopy, and computational simulations. Results show that HHL forms predominantly 1:1 complexes with Ag+ ( Kd = 3.41 × 10-4 M) or Cu2+ ( Kd = 1.40 × 10-5 M), with the coordination chemistry occurring on the oxygen moieties. In vivo experiments with Chromobacterium violaceum CV026 show that sublethal concentrations of Ag+ and Cu2+ decreased HHL-regulated QS activity. Furthermore, when Ag+ was preincubated with HHL, Ag+ toxicity to CV026 decreased by an order of magnitude, suggesting HHL:metal complexes alter the bioavailability of the individual constituents.
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Affiliation(s)
- Eric McGivney
- Department of Civil and Environmental Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States
- Center for the Environmental Implications of NanoTechnology (CEINT), Durham, North Carolina, United States
| | | | - Bandrea Weber
- Department of Civil and Environmental Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States
| | | | - Jeanne M. VanBriesen
- Department of Civil and Environmental Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States
- Center for the Environmental Implications of NanoTechnology (CEINT), Durham, North Carolina, United States
| | - Kelvin B. Gregory
- Department of Civil and Environmental Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States
- Center for the Environmental Implications of NanoTechnology (CEINT), Durham, North Carolina, United States
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Saraiva RG, Huitt-Roehl CR, Tripathi A, Cheng YQ, Bosch J, Townsend CA, Dimopoulos G. Chromobacterium spp. mediate their anti-Plasmodium activity through secretion of the histone deacetylase inhibitor romidepsin. Sci Rep 2018; 8:6176. [PMID: 29670144 PMCID: PMC5906607 DOI: 10.1038/s41598-018-24296-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Accepted: 03/19/2018] [Indexed: 12/03/2022] Open
Abstract
The Chromobacterium sp. Panama bacterium has in vivo and in vitro anti-Plasmodium properties. To assess the nature of the Chromobacterium-produced anti-Plasmodium factors, chemical partition was conducted by bioassay-guided fractionation where different fractions were assayed for activity against asexual stages of P. falciparum. The isolated compounds were further partitioned by reversed-phase FPLC followed by size-exclusion chromatography; high resolution UPLC and ESI/MS data were then collected and revealed that the most active fraction contained a cyclic depsipeptide, which was identified as romidepsin. A pure sample of this FDA-approved HDAC inhibitor allowed us to independently verify this finding, and establish that romidepsin also has potent effect against mosquito stages of the parasite's life cycle. Genomic comparisons between C. sp. Panama and multiple species within the Chromobacterium genus further demonstrated a correlation between presence of the gene cluster responsible for romidepsin production and effective antiplasmodial activity. A romidepsin-null Chromobacterium spp. mutant loses its anti-Plasmodium properties by losing the ability to inhibit P. falciparum HDAC activity, and romidepsin is active against resistant parasites to commonly deployed antimalarials. This independent mode of action substantiates exploring a chromobacteria-based approach for malaria transmission-blocking.
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Affiliation(s)
- Raúl G Saraiva
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | | | - Abhai Tripathi
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - Yi-Qiang Cheng
- UNT System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, TX, USA
| | - Jürgen Bosch
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
- InterRayBio, LLC, Baltimore, Maryland, USA
| | - Craig A Townsend
- Department of Chemistry, Johns Hopkins University, Baltimore, MD, USA
| | - George Dimopoulos
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA.
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168
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Bacterial interspecies quorum sensing in the mammalian gut microbiota. C R Biol 2018; 341:297-299. [PMID: 29631889 DOI: 10.1016/j.crvi.2018.03.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Accepted: 03/13/2018] [Indexed: 02/08/2023]
Abstract
The mammalian gastrointestinal tract harbors a diverse and complex resident bacterial community, which interacts with the host in many beneficial processes required for optimal host health. We are studying the importance of bacterial cell-cell communication mediated by the interspecies quorum-sensing signal autoinducer-2 (AI-2) in the beneficial properties of the gut microbiota. Our recent work provided the first evidence that AI-2 produced by Escherichia coli can influence the species composition of this community in the mouse gut. We showed that, under conditions of microbiota imbalances induced by antibiotic treatments, E. coli, which increases intestinal AI-2 levels, not only had an effect on the overall structure of the microbiota community, but specifically favored the expansion of the Firmicutes phylum. Because the Firmicutes are very important for many gut functions and were the group of bacteria most severely affected by antibiotic treatment with streptomycin, we are addressing the possibility that AI-2 can influence the balance of the major bacterial groups in the gut and promote recovery of gut homeostasis. Overall, we want to understand how bacterial chemical signaling shapes the multi-species bacterial communities in the mammalian gut and how these communities affect host physiology.
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169
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Chagas FO, Pessotti RDC, Caraballo-Rodríguez AM, Pupo MT. Chemical signaling involved in plant-microbe interactions. Chem Soc Rev 2018; 47:1652-1704. [PMID: 29218336 DOI: 10.1039/c7cs00343a] [Citation(s) in RCA: 91] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Microorganisms are found everywhere, and they are closely associated with plants. Because the establishment of any plant-microbe association involves chemical communication, understanding crosstalk processes is fundamental to defining the type of relationship. Although several metabolites from plants and microbes have been fully characterized, their roles in the chemical interplay between these partners are not well understood in most cases, and they require further investigation. In this review, we describe different plant-microbe associations from colonization to microbial establishment processes in plants along with future prospects, including agricultural benefits.
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Affiliation(s)
- Fernanda Oliveira Chagas
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo (FCFRP-USP), Avenida do Café, s/n, 14040-903, Ribeirão Preto-SP, Brazil.
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170
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Synergistic activity of cosecreted natural products from amoebae-associated bacteria. Proc Natl Acad Sci U S A 2018; 115:3758-3763. [PMID: 29592954 DOI: 10.1073/pnas.1721790115] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Investigating microbial interactions from an ecological perspective is a particularly fruitful approach to unveil both new chemistry and bioactivity. Microbial predator-prey interactions in particular rely on natural products as signal or defense molecules. In this context, we identified a grazing-resistant Pseudomonas strain, isolated from the bacterivorous amoeba Dictyostelium discoideum. Genome analysis of this bacterium revealed the presence of two biosynthetic gene clusters that were found adjacent to each other on a contiguous stretch of the bacterial genome. Although one cluster codes for the polyketide synthase producing the known antibiotic mupirocin, the other cluster encodes a nonribosomal peptide synthetase leading to the unreported cyclic lipopeptide jessenipeptin. We describe its complete structure elucidation, as well as its synergistic activity against methicillin-resistant Staphylococcus aureus, when in combination with mupirocin. Both biosynthetic gene clusters are regulated by quorum-sensing systems, with 3-oxo-decanoyl homoserine lactone (3-oxo-C10-AHL) and hexanoyl homoserine lactone (C6-AHL) being the respective signal molecules. This study highlights the regulation, richness, and complex interplay of bacterial natural products that emerge in the context of microbial competition.
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171
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Meyer N, Bigalke A, Kaulfuß A, Pohnert G. Strategies and ecological roles of algicidal bacteria. FEMS Microbiol Rev 2018; 41:880-899. [PMID: 28961821 DOI: 10.1093/femsre/fux029] [Citation(s) in RCA: 92] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Accepted: 05/31/2017] [Indexed: 12/21/2022] Open
Abstract
In both freshwater and marine ecosystems, phytoplankton are the most dominant primary producers, contributing substantially to aquatic food webs. Algicidal bacteria that can associate to microalgae from the phytoplankton have the capability to control the proliferation and even to lyse them. These bacteria thus play an important role in shaping species composition in pelagic environments. In this review, we discuss and categorise strategies used by algicidal bacteria for the attack on microalgae. We highlight the complex regulation of algicidal activity and defence responses that govern alga-bacteria interactions. We also discuss how algicidal bacteria impact algal physiology and metabolism and survey the existing algicidal metabolites and enzymes. The review illustrates that the ecological role of algicidal bacteria is not yet fully understood and critically discusses the challenges in obtaining ecologically relevant data.
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Affiliation(s)
- Nils Meyer
- Institute for Inorganic and Analytical Chemistry, Bioorganic Analytics, Friedrich-Schiller-Universität Jena, Lessingstrasse 8, D-07743 Jena, Germany
| | - Arite Bigalke
- Institute for Inorganic and Analytical Chemistry, Bioorganic Analytics, Friedrich-Schiller-Universität Jena, Lessingstrasse 8, D-07743 Jena, Germany
| | - Anett Kaulfuß
- Institute for Inorganic and Analytical Chemistry, Bioorganic Analytics, Friedrich-Schiller-Universität Jena, Lessingstrasse 8, D-07743 Jena, Germany
| | - Georg Pohnert
- Institute for Inorganic and Analytical Chemistry, Bioorganic Analytics, Friedrich-Schiller-Universität Jena, Lessingstrasse 8, D-07743 Jena, Germany.,Max Planck Institute for Chemical Ecology, Hans Knöll Str. 8, D-07745 Jena, Germany
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172
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173
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Peng H, Ouyang Y, Bilal M, Wang W, Hu H, Zhang X. Identification, synthesis and regulatory function of the N-acylated homoserine lactone signals produced by Pseudomonas chlororaphis HT66. Microb Cell Fact 2018; 17:9. [PMID: 29357848 PMCID: PMC5776774 DOI: 10.1186/s12934-017-0854-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Accepted: 12/20/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Pseudomonas chlororaphis HT66 isolated from the rice rhizosphere is an important plant growth-promoting rhizobacteria that produce phenazine-1-carboxamide (PCN) in high yield. Phenazine production is regulated by a quorum sensing (QS) system that involves the N-acylated homoserine lactones (AHLs)-a prevalent type of QS molecule. RESULTS Three QS signals were detected by thin layer chromatography (TLC) and high-performance liquid chromatography-mass spectrometry (HPLC-MS/MS), which identified to be N-(3-hydroxy hexanoyl)-L-homoserine lactone (3-OH-C6-HSL), N-(3-hydroxy octanoyl)-L-homoserine lactone (3-OH-C8-HSL) and N-(3-hydroxy decanoyl)-L-homoserine lactone (3-OH-C10-HSL). The signal types and methods of synthesis were different from that in other phenazine-producing Pseudomonas strains. By non-scar deletion and heterologous expression techniques, the biosynthesis of the AHL-signals was confirmed to be only catalyzed by PhzI, while other AHLs synthases i.e., CsaI and HdtS were not involved in strain HT66. In comparison to wild-type HT66, PCN production was 2.3-folds improved by over-expression of phzI, however, phzI or phzR mutant did not produce PCN. The cell growth of HT66∆phzI mutant was significantly decreased, and the biofilm formation in phzI or phzR inactivated strains of HT66 decreased to various extents. CONCLUSION In conclusion, the results demonstrate that PhzI-PhzR system plays a critical role in numerous biological processes including phenazine production.
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Affiliation(s)
- Huasong Peng
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, People's Republic of China.
| | - Yi Ouyang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, People's Republic of China
| | - Muhammad Bilal
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, People's Republic of China
| | - Wei Wang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, People's Republic of China
| | - Hongbo Hu
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, People's Republic of China
| | - Xuehong Zhang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, People's Republic of China
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174
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Naik SP, Scholin J, Ching S, Chi F, Herpfer M. Quorum Sensing Disruption in Vibrio harveyi Bacteria by Clay Materials. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2018; 66:40-44. [PMID: 29231719 DOI: 10.1021/acs.jafc.7b03918] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
This work describes the use of clay minerals as catalysts for the degradation of quorum sensing molecule N-(3-oxooctanoyl)-dl-homoserine lactone. Certain clay minerals as a result of their surface properties and porosity can catalytically degrade the quorum sensing molecule into smaller fragments. The disruption of quorum sensing by clay in a growing Gram-negative Vibrio harveyi bacteria culture was also studied by monitoring luminescence and population density of the bacteria, wherein quenching of bacterial quorum sensing activity was observed by means of luminescence reduction. The results of this study show that food-grade clays can be used as biocatalysts in disrupting bacterial activity in various media.
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Affiliation(s)
- Sajo P Naik
- Innovation Center, Oil-Dri Corporation of America , 777 Forest Edge Road, Vernon Hills, Illinois 60061-3197, United States
| | - Jonathon Scholin
- Innovation Center, Oil-Dri Corporation of America , 777 Forest Edge Road, Vernon Hills, Illinois 60061-3197, United States
| | - San Ching
- Innovation Center, Oil-Dri Corporation of America , 777 Forest Edge Road, Vernon Hills, Illinois 60061-3197, United States
| | - Fang Chi
- Innovation Center, Oil-Dri Corporation of America , 777 Forest Edge Road, Vernon Hills, Illinois 60061-3197, United States
| | - Marc Herpfer
- Innovation Center, Oil-Dri Corporation of America , 777 Forest Edge Road, Vernon Hills, Illinois 60061-3197, United States
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175
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Mariam J, Anand R. Fluorescence Quenching Studies of γ-Butyrolactone-Binding Protein (CprB) from Streptomyces coelicolor A3(2). Methods Mol Biol 2018; 1673:131-143. [PMID: 29130170 DOI: 10.1007/978-1-4939-7309-5_11] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Fluorescence spectroscopy is an important analytical tool which is widely employed to study biological systems. This technique can be applied to qualitatively and quantitatively probe protein-ligand interactions primarily because of its sensitivity, selectivity, nondestructive and rapid form of analysis. In this chapter we describe the utility of this technique to establish a label-free, universal screening protocol for putative γ-butyrolactone (GBL) receptors by exploiting the intrinsic fluorescence of a highly conserved tryptophan residue that constitutes the hydrophobic pocket for GBL binding, a unique feature possessed by this family of receptors. Here we demonstrate this technique using a combination of steady-state fluorescence quenching methods and fluorescence lifetime decay kinetics using CprB protein from Streptomyces coelicolor A3(2) as a model system. Interaction data between CprB and two chemically synthesized GBLs involved in quorum sensing, Cp1 and Cp2, have been used as example.
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Affiliation(s)
- Jessy Mariam
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai, Maharashtra, 400076, India
| | - Ruchi Anand
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai, Maharashtra, 400076, India.
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176
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Hudson J, Gardiner M, Deshpande N, Egan S. Transcriptional response of Nautella italica R11 towards its macroalgal host uncovers new mechanisms of host-pathogen interaction. Mol Ecol 2017; 27:1820-1832. [PMID: 29215165 DOI: 10.1111/mec.14448] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 11/21/2017] [Accepted: 11/24/2017] [Indexed: 12/14/2022]
Abstract
Macroalgae (seaweeds) are essential for the functioning of temperate marine ecosystems, but there is increasing evidence to suggest that their survival is under threat from anthropogenic stressors and disease. Nautella italica R11 is recognized as an aetiological agent of bleaching disease in the red alga, Delisea pulchra. Yet, there is a lack of knowledge surrounding the molecular mechanisms involved in this model host-pathogen interaction. Here we report that mutations in the gene encoding for a LuxR-type quorum sensing transcriptional regulator, RaiR, render N. italica R11 avirulent, suggesting this gene is important for regulating the expression of virulence phenotypes. Using an RNA sequencing approach, we observed a strong transcriptional response of N. italica R11 towards the presence of D. pulchra. In particular, genes involved in oxidative stress resistance, carbohydrate and central metabolism were upregulated in the presence of the host, suggesting a role for these functions in the opportunistic pathogenicity of N. italica R11. Furthermore, we show that RaiR regulates a subset of genes in N. italica R11, including those involved in metabolism and the expression of phage-related proteins. The outcome of this research reveals new functions important for virulence of N. italica R11 and contributes to our greater understanding of the complex factors mitigating microbial diseases in macroalgae.
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Affiliation(s)
- Jennifer Hudson
- School of Biological, Earth and Environmental Sciences, Centre for Marine Bio-Innovation, UNSW Sydney, Sydney, NSW, Australia
| | - Melissa Gardiner
- School of Biological, Earth and Environmental Sciences, Centre for Marine Bio-Innovation, UNSW Sydney, Sydney, NSW, Australia
| | - Nandan Deshpande
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, NSW, Australia
| | - Suhelen Egan
- School of Biological, Earth and Environmental Sciences, Centre for Marine Bio-Innovation, UNSW Sydney, Sydney, NSW, Australia
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Chen H, Li A, Cui D, Wang Q, Wu D, Cui C, Ma F. N-Acyl-homoserine lactones and autoinducer-2-mediated quorum sensing during wastewater treatment. Appl Microbiol Biotechnol 2017; 102:1119-1130. [DOI: 10.1007/s00253-017-8697-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Revised: 12/04/2017] [Accepted: 12/06/2017] [Indexed: 12/16/2022]
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178
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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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179
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The Complex Quorum Sensing Circuitry of Burkholderia thailandensis Is Both Hierarchically and Homeostatically Organized. mBio 2017; 8:mBio.01861-17. [PMID: 29208745 PMCID: PMC5717390 DOI: 10.1128/mbio.01861-17] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The genome of the bacterium Burkholderia thailandensis encodes three complete LuxI/LuxR-type quorum sensing (QS) systems: BtaI1/BtaR1 (QS-1), BtaI2/BtaR2 (QS-2), and BtaI3/BtaR3 (QS-3). The LuxR-type transcriptional regulators BtaR1, BtaR2, and BtaR3 modulate the expression of target genes in association with various N-acyl-l-homoserine lactones (AHLs) as signaling molecules produced by the LuxI-type synthases BtaI1, BtaI2, and BtaI3. We have systematically dissected the complex QS circuitry of B. thailandensis strain E264. Direct quantification of N-octanoyl-homoserine lactone (C8-HSL), N-3-hydroxy-decanoyl-homoserine lactone (3OHC10-HSL), and N-3-hydroxy-octanoyl-homoserine lactone (3OHC8-HSL), the primary AHLs produced by this bacterium, was performed by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) in the wild-type strain and in QS deletion mutants. This was compared to the transcription of btaI1, btaI2, and btaI3 using chromosomal mini-CTX-lux transcriptional reporters. Furthermore, the levels of expression of btaR1, btaR2, and btaR3 were monitored by quantitative reverse transcription-PCR (qRT-PCR). We observed that C8-HSL, 3OHC10-HSL, and 3OHC8-HSL are differentially produced over time during bacterial growth and correlate with the btaI1, btaI2, and btaI3 gene expression profiles, revealing a successive activation of the corresponding QS systems. Moreover, the transcription of the btaR1, btaR2, and btaR3 genes is modulated by cognate and noncognate AHLs, showing that their regulation depends on themselves and on other QS systems. We conclude that the three QS systems in B. thailandensis are interdependent, suggesting that they cooperate dynamically and function in a concerted manner in modulating the expression of QS target genes through a successive regulatory network. Quorum sensing (QS) is a widespread bacterial communication system coordinating the expression of specific genes in a cell density-dependent manner and allowing bacteria to synchronize their activities and to function as multicellular communities. QS plays a crucial role in bacterial pathogenicity by regulating the expression of a wide spectrum of virulence/survival factors and is essential to environmental adaptation. The results presented here demonstrate that the multiple QS systems coexisting in the bacterium Burkholderia thailandensis, which is considered the avirulent version of the human pathogen Burkholderia pseudomallei and thus commonly used as an alternative study model, are hierarchically and homeostatically organized. We found these QS systems to be finely integrated into a complex regulatory network, including transcriptional and posttranscriptional interactions, and further incorporating growth stages and temporal expression. These results provide a unique, comprehensive illustration of a sophisticated QS network and will contribute to a better comprehension of the regulatory mechanisms that can be involved in the expression of QS-controlled genes, in particular those associated with the establishment of host-pathogen interactions and acclimatization to the environment.
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Burkholderia cenocepacia integrates cis-2-dodecenoic acid and cyclic dimeric guanosine monophosphate signals to control virulence. Proc Natl Acad Sci U S A 2017; 114:13006-13011. [PMID: 29158389 DOI: 10.1073/pnas.1709048114] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Quorum sensing (QS) signals are used by bacteria to regulate biological functions in response to cell population densities. Cyclic diguanosine monophosphate (c-di-GMP) regulates cell functions in response to diverse environmental chemical and physical signals that bacteria perceive. In Burkholderia cenocepacia, the QS signal receptor RpfR degrades intracellular c-di-GMP when it senses the QS signal cis-2-dodecenoic acid, also called Burkholderia diffusible signal factor (BDSF), as a proxy for high cell density. However, it was unclear how this resulted in control of BDSF-regulated phenotypes. Here, we found that RpfR forms a complex with a regulator named GtrR (BCAL1536) to enhance its binding to target gene promoters under circumstances where the BDSF signal binds to RpfR to stimulate its c-di-GMP phosphodiesterase activity. In the absence of BDSF, c-di-GMP binds to the RpfR-GtrR complex and inhibits its ability to control gene expression. Mutations in rpfR and gtrR had overlapping effects on both the B. cenocepacia transcriptome and BDSF-regulated phenotypes, including motility, biofilm formation, and virulence. These results show that RpfR is a QS signal receptor that also functions as a c-di-GMP sensor. This protein thus allows B. cenocepacia to integrate information about its physical and chemical surroundings as well as its population density to control diverse biological functions including virulence. This type of QS system appears to be widely distributed in beta and gamma proteobacteria.
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181
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Involvement of cyclodipeptides in the competition of bacterial communities in the oligotrophic Churince aquatic system of Cuatro Ciénegas Basin dominated by Gammaproteobacteria. Extremophiles 2017; 22:73-85. [DOI: 10.1007/s00792-017-0978-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 11/03/2017] [Indexed: 01/10/2023]
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182
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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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183
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Yavuztürk Gül B, Koyuncu I. Assessment of new environmental quorum quenching bacteria as a solution for membrane biofouling. Process Biochem 2017. [DOI: 10.1016/j.procbio.2017.05.030] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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184
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Jayathilake PG, Jana S, Rushton S, Swailes D, Bridgens B, Curtis T, Chen J. Extracellular Polymeric Substance Production and Aggregated Bacteria Colonization Influence the Competition of Microbes in Biofilms. Front Microbiol 2017; 8:1865. [PMID: 29021783 PMCID: PMC5623813 DOI: 10.3389/fmicb.2017.01865] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 09/12/2017] [Indexed: 11/25/2022] Open
Abstract
The production of extracellular polymeric substance (EPS) is important for the survival of biofilms. However, EPS production is costly for bacteria and the bacterial strains that produce EPS (EPS+) grow in the same environment as non-producers (EPS-) leading to competition between these strains for nutrients and space. The outcome of this competition is likely to be dependent on factors such as initial attachment, EPS production rate, ambient nutrient levels and quorum sensing. We use an Individual-based Model (IbM) to study the competition between EPS+ and EPS- strains by varying the nature of initial colonizers which can either be in the form of single cells or multicellular aggregates. The microbes with EPS+ characteristics obtain a competitive advantage if they initially colonize the surface as smaller aggregates and are widely spread-out between the cells of EPS-, when both are deposited on the substratum. Furthermore, the results show that quorum sensing-regulated EPS production may significantly reduce the fitness of EPS producers when they initially deposit as aggregates. The results provide insights into how the distribution of bacterial aggregates during initial colonization could be a deciding factor in the competition among different strains in biofilms.
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Affiliation(s)
| | - Saikat Jana
- School of Engineering, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Steve Rushton
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - David Swailes
- School of Mathematics, Statistics and Physics, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Ben Bridgens
- School of Engineering, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Tom Curtis
- Centre for Synthetic Biology and the Bioeconomy, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Jinju Chen
- School of Engineering, Newcastle University, Newcastle upon Tyne, United Kingdom
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185
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Engstrom MD, Pfleger BF. Transcription control engineering and applications in synthetic biology. Synth Syst Biotechnol 2017; 2:176-191. [PMID: 29318198 PMCID: PMC5655343 DOI: 10.1016/j.synbio.2017.09.003] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 09/26/2017] [Accepted: 09/26/2017] [Indexed: 12/18/2022] Open
Abstract
In synthetic biology, researchers assemble biological components in new ways to produce systems with practical applications. One of these practical applications is control of the flow of genetic information (from nucleic acid to protein), a.k.a. gene regulation. Regulation is critical for optimizing protein (and therefore activity) levels and the subsequent levels of metabolites and other cellular properties. The central dogma of molecular biology posits that information flow commences with transcription, and accordingly, regulatory tools targeting transcription have received the most attention in synthetic biology. In this mini-review, we highlight many past successes and summarize the lessons learned in developing tools for controlling transcription. In particular, we focus on engineering studies where promoters and transcription terminators (cis-factors) were directly engineered and/or isolated from DNA libraries. We also review several well-characterized transcription regulators (trans-factors), giving examples of how cis- and trans-acting factors have been combined to create digital and analogue switches for regulating transcription in response to various signals. Last, we provide examples of how engineered transcription control systems have been used in metabolic engineering and more complicated genetic circuits. While most of our mini-review focuses on the well-characterized bacterium Escherichia coli, we also provide several examples of the use of transcription control engineering in non-model organisms. Similar approaches have been applied outside the bacterial kingdom indicating that the lessons learned from bacterial studies may be generalized for other organisms.
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Affiliation(s)
- Michael D. Engstrom
- Genetics-Biotechnology Center, University of Wisconsin-Madison School of Medicine and Public Health, USA
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison College of Engineering, USA
| | - Brian F. Pfleger
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison College of Engineering, USA
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, USA
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186
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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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187
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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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188
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Bauer M, Knebel J, Lechner M, Pickl P, Frey E. Ecological feedback in quorum-sensing microbial populations can induce heterogeneous production of autoinducers. eLife 2017; 6. [PMID: 28741470 PMCID: PMC5526673 DOI: 10.7554/elife.25773] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2017] [Accepted: 06/15/2017] [Indexed: 12/11/2022] Open
Abstract
Autoinducers are small signaling molecules that mediate intercellular communication in microbial populations and trigger coordinated gene expression via ‘quorum sensing’. Elucidating the mechanisms that control autoinducer production is, thus, pertinent to understanding collective microbial behavior, such as virulence and bioluminescence. Recent experiments have shown a heterogeneous promoter activity of autoinducer synthase genes, suggesting that some of the isogenic cells in a population might produce autoinducers, whereas others might not. However, the mechanism underlying this phenotypic heterogeneity in quorum-sensing microbial populations has remained elusive. In our theoretical model, cells synthesize and secrete autoinducers into the environment, up-regulate their production in this self-shaped environment, and non-producers replicate faster than producers. We show that the coupling between ecological and population dynamics through quorum sensing can induce phenotypic heterogeneity in microbial populations, suggesting an alternative mechanism to stochastic gene expression in bistable gene regulatory circuits. DOI:http://dx.doi.org/10.7554/eLife.25773.001 Bacteria and other microbes can communicate with each other using chemical languages. They release small signaling molecules called autoinducers into their surroundings and sense the levels of the autoinducers in the environment. The response to these autoinducers – known as quorum sensing – can regulate how whole communities of microbes grow and behave; for example, autoinducers can alter the ability of microbes to infect humans or enable the microbes to collectively switch on light production. Recent experiments suggest that, in a population of genetically identical microbes, some individuals may produce autoinducers while others do not. The coexistence of these different “phenotypes” in one population may enable different individuals to perform different roles, or act as a “bet-hedging” strategy that helps the population to survive if it is later exposed to a stressful situation. It is not clear how microbes regulate autoinducer production so that only some individuals produce these molecules. Bauer, Knebel et al. developed a theoretical model to address this question. In the model, the microbes shape their environment by producing autoinducers and can respond to this self-shaped environment by changing their level of autoinducer production. Bauer, Knebel et al. found that this establishes a feedback loop that can result in autoinducers being produced by some individuals but not others. The next step following on from this work is to carry out experiments to test the assumptions and predictions made by the theoretical model. These findings may help to understand how the coexistence of different phenotypes affects collective behaviors, and vice versa, in populations of microbes that use quorum-sensing. DOI:http://dx.doi.org/10.7554/eLife.25773.002
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Affiliation(s)
- Matthias Bauer
- Arnold Sommerfeld Center for Theoretical Physics and Center for NanoScience, Department of Physics, Ludwig-Maximilians-Universität München, München, Germany
| | - Johannes Knebel
- Arnold Sommerfeld Center for Theoretical Physics and Center for NanoScience, Department of Physics, Ludwig-Maximilians-Universität München, München, Germany
| | - Matthias Lechner
- Arnold Sommerfeld Center for Theoretical Physics and Center for NanoScience, Department of Physics, Ludwig-Maximilians-Universität München, München, Germany
| | - Peter Pickl
- Department of Mathematics, Ludwig-Maximilians-Universität München, München, Germany
| | - Erwin Frey
- Arnold Sommerfeld Center for Theoretical Physics and Center for NanoScience, Department of Physics, Ludwig-Maximilians-Universität München, München, Germany
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189
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Mukherjee S, Moustafa D, Smith CD, Goldberg JB, Bassler BL. The RhlR quorum-sensing receptor controls Pseudomonas aeruginosa pathogenesis and biofilm development independently of its canonical homoserine lactone autoinducer. PLoS Pathog 2017; 13:e1006504. [PMID: 28715477 PMCID: PMC5531660 DOI: 10.1371/journal.ppat.1006504] [Citation(s) in RCA: 117] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Revised: 07/27/2017] [Accepted: 07/01/2017] [Indexed: 12/22/2022] Open
Abstract
Quorum sensing (QS) is a bacterial cell-to-cell communication process that relies on the production, release, and response to extracellular signaling molecules called autoinducers. QS controls virulence and biofilm formation in the human pathogen Pseudomonas aeruginosa. P. aeruginosa possesses two canonical LuxI/R-type QS systems, LasI/R and RhlI/R, which produce and detect 3OC12-homoserine lactone and C4-homoserine lactone, respectively. Here, we use biofilm analyses, reporter assays, RNA-seq studies, and animal infection assays to show that RhlR directs both RhlI-dependent and RhlI-independent regulons. In the absence of RhlI, RhlR controls the expression of genes required for biofilm formation as well as genes encoding virulence factors. Consistent with these findings, ΔrhlR and ΔrhlI mutants have radically different biofilm phenotypes and the ΔrhlI mutant displays full virulence in animals whereas the ΔrhlR mutant is attenuated. The ΔrhlI mutant cell-free culture fluids contain an activity that stimulates RhlR-dependent gene expression. We propose a model in which RhlR responds to an alternative ligand, in addition to its canonical C4-homoserine lactone autoinducer. This alternate ligand promotes a RhlR-dependent transcriptional program in the absence of RhlI.
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Affiliation(s)
- Sampriti Mukherjee
- Princeton University, Department of Molecular Biology, Princeton, NJ, United States of America
| | - Dina Moustafa
- Emory University School of Medicine, Children’s Healthcare of Atlanta, Inc., Department of Pediatrics, and Center for Cystic Fibrosis and Airway Diseases Research, Atlanta, GA, United States of America
| | - Chari D. Smith
- Princeton University, Department of Molecular Biology, Princeton, NJ, United States of America
| | - Joanna B. Goldberg
- Emory University School of Medicine, Children’s Healthcare of Atlanta, Inc., Department of Pediatrics, and Center for Cystic Fibrosis and Airway Diseases Research, Atlanta, GA, United States of America
| | - Bonnie L. Bassler
- Princeton University, Department of Molecular Biology, Princeton, NJ, United States of America
- Howard Hughes Medical Institute, Chevy Chase, MD, United States of America
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190
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Zúñiga A, Donoso RA, Ruiz D, Ruz GA, González B. Quorum-Sensing Systems in the Plant Growth-Promoting Bacterium Paraburkholderia phytofirmans PsJN Exhibit Cross-Regulation and Are Involved in Biofilm Formation. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2017; 30:557-565. [PMID: 28548604 DOI: 10.1094/mpmi-01-17-0008-r] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Quorum-sensing systems play important roles in host colonization and host establishment of Burkholderiales species. Beneficial Paraburkholderia species share a conserved quorum-sensing (QS) system, designated BraI/R, that controls different phenotypes. In this context, the plant growth-promoting bacterium Paraburkholderia phytofirmans PsJN possesses two different homoserine lactone QS systems BpI.1/R.1 and BpI.2/R.2 (BraI/R-like QS system). The BpI.1/R.1 QS system was previously reported to be important to colonize and produce beneficial effects in Arabidopsis thaliana plants. Here, we analyzed the temporal variations of the QS gene transcript levels in the wild-type strain colonizing plant roots. The gene expression patterns showed relevant differences in both QS systems compared with the wild-type strain in the unplanted control treatment. The gene expression data were used to reconstruct a regulatory network model of QS systems in P. phytofirmans PsJN, using a Boolean network model. Also, we examined the phenotypic traits and transcript levels of genes involved in QS systems, using P. phytofirmans mutants in homoserine lactone synthases genes. We observed that the BpI.1/R.1 QS system regulates biofilm formation production in strain PsJN and this phenotype was associated with the lower expression of a specific extracytoplasmic function sigma factor ecf26.1 gene (implicated in biofilm formation) in the bpI.1 mutant strain.
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Affiliation(s)
- Ana Zúñiga
- Facultad de Ingeniería y Ciencias, Universidad Adolfo Ibáñez, Millennium Nucleus Center for Plant Systems and Synthetic Biology, and Center of Applied Ecology and Sustainability (CAPES), Santiago, Chile
| | - Raúl A Donoso
- Facultad de Ingeniería y Ciencias, Universidad Adolfo Ibáñez, Millennium Nucleus Center for Plant Systems and Synthetic Biology, and Center of Applied Ecology and Sustainability (CAPES), Santiago, Chile
| | - Daniela Ruiz
- Facultad de Ingeniería y Ciencias, Universidad Adolfo Ibáñez, Millennium Nucleus Center for Plant Systems and Synthetic Biology, and Center of Applied Ecology and Sustainability (CAPES), Santiago, Chile
| | - Gonzalo A Ruz
- Facultad de Ingeniería y Ciencias, Universidad Adolfo Ibáñez, Millennium Nucleus Center for Plant Systems and Synthetic Biology, and Center of Applied Ecology and Sustainability (CAPES), Santiago, Chile
| | - Bernardo González
- Facultad de Ingeniería y Ciencias, Universidad Adolfo Ibáñez, Millennium Nucleus Center for Plant Systems and Synthetic Biology, and Center of Applied Ecology and Sustainability (CAPES), Santiago, Chile
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191
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Nandakumar N, Dandela R, Gopas J, Meijler MM. Quorum sensing modulators exhibit cytotoxicity in Hodgkin’s lymphoma cells and interfere with NF-κB signaling. Bioorg Med Chem Lett 2017; 27:2967-2973. [DOI: 10.1016/j.bmcl.2017.05.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 05/01/2017] [Accepted: 05/03/2017] [Indexed: 01/06/2023]
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192
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Post-secretional activation of Protease IV by quorum sensing in Pseudomonas aeruginosa. Sci Rep 2017; 7:4416. [PMID: 28667333 PMCID: PMC5493658 DOI: 10.1038/s41598-017-03733-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 05/02/2017] [Indexed: 11/08/2022] Open
Abstract
Protease IV (PIV), a key virulence factor of Pseudomonas aeruginosa is a secreted lysyl-endopeptidase whose expression is induced by quorum sensing (QS). We found that PIV expressed in QS mutant has severe reduction of activity in culture supernatant (CS), even though it is overexpressed to high level. PIV purified from the QS mutant (M-PIV) had much lower activity than the PIV purified from wild type (P-PIV). We found that the propeptide cleaved from prepro-PIV was co-purified with M-PIV, but never with P-PIV. Since the activity of M-PIV was restored by adding the CS of QS-positive and PIV-deficient strain, we hypothesized that the propeptide binds to and inhibits PIV, and is degraded to activate PIV by a QS-dependent factor. In fact, the CS of the QS-positive and PIV-deficient strain was able to degrade the propeptide. Since the responsible factor should be a QS-dependently expressed extracellular protease, we tested QS-dependent proteases of P. aeruginosa and found that LasB (elastase) can degrade the propeptide and activate M-PIV. We purified the propeptide of PIV and confirmed that the propeptide can bind to and inhibit PIV. We suggest that PIV is post-secretionally activated through the extracellular degradation of the propeptide by LasB, a QS-dependent protease.
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193
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Doberva M, Stien D, Sorres J, Hue N, Sanchez-Ferandin S, Eparvier V, Ferandin Y, Lebaron P, Lami R. Large Diversity and Original Structures of Acyl-Homoserine Lactones in Strain MOLA 401, a Marine Rhodobacteraceae Bacterium. Front Microbiol 2017; 8:1152. [PMID: 28690598 PMCID: PMC5479921 DOI: 10.3389/fmicb.2017.01152] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 06/07/2017] [Indexed: 01/01/2023] Open
Abstract
Quorum sensing (QS) is a density-dependent mechanism allowing bacteria to synchronize their physiological activities, mediated by a wide range of signaling molecules including N-acyl-homoserine lactones (AHLs). Production of AHL has been identified in various marine strains of Proteobacteria. However, the chemical diversity of these molecules still needs to be further explored. In this study, we examined the diversity of AHLs produced by strain MOLA 401, a marine Alphaproteobacterium that belongs to the ubiquitous Rhodobacteraceae family. We combined an original biosensors-based guided screening of extract microfractions with liquid chromatography coupled to mass spectrometry (MS), High Resolution MS/MS and Nuclear Magnetic Resonance. This approach revealed the unsuspected capacity of a single Rhodobacteraceae strain to synthesize 20 different compounds, which are most likely AHLs. Also, some of these AHLs possessed original features that have never been previously observed, including long (up to 19 carbons) and poly-hydroxylated acyl side chains, revealing new molecular adaptations of QS to planktonic life and a larger molecular diversity than expected of molecules involved in cell–cell signaling within a single strain.
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Affiliation(s)
- Margot Doberva
- Sorbonne Universités, UPMC Univ Paris 6, CNRS, Laboratoire de Biodiversité et Biotechnologies Microbiennes (LBBM), Observatoire OcéanologiqueBanyuls/Mer, France
| | - Didier Stien
- Sorbonne Universités, UPMC Univ Paris 6, CNRS, Laboratoire de Biodiversité et Biotechnologies Microbiennes (LBBM), Observatoire OcéanologiqueBanyuls/Mer, France
| | - Jonathan Sorres
- Sorbonne Universités, UPMC Univ Paris 6, CNRS, Laboratoire de Biodiversité et Biotechnologies Microbiennes (LBBM), Observatoire OcéanologiqueBanyuls/Mer, France
| | - Nathalie Hue
- CNRS, Institut de Chimie des Substances Naturelles (ICSN), Université Paris-SudGif-sur-Yvette, France
| | - Sophie Sanchez-Ferandin
- Sorbonne Universités, UPMC Univ Paris 6, CNRS, Biologie Intégrative des Organismes Marins (BIOM), Observatoire OcéanologiqueBanyuls/Mer, France
| | - Véronique Eparvier
- CNRS, Institut de Chimie des Substances Naturelles (ICSN), Université Paris-SudGif-sur-Yvette, France
| | - Yoan Ferandin
- Sorbonne Universités, UPMC Univ Paris 6, CNRS, Laboratoire de Biodiversité et Biotechnologies Microbiennes (LBBM), Observatoire OcéanologiqueBanyuls/Mer, France
| | - Philippe Lebaron
- Sorbonne Universités, UPMC Univ Paris 6, CNRS, Laboratoire de Biodiversité et Biotechnologies Microbiennes (LBBM), Observatoire OcéanologiqueBanyuls/Mer, France
| | - Raphaël Lami
- Sorbonne Universités, UPMC Univ Paris 6, CNRS, Laboratoire de Biodiversité et Biotechnologies Microbiennes (LBBM), Observatoire OcéanologiqueBanyuls/Mer, France
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194
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Bodelón G, Montes-García V, Costas C, Pérez-Juste I, Pérez-Juste J, Pastoriza-Santos I, Liz-Marzán LM. Imaging Bacterial Interspecies Chemical Interactions by Surface-Enhanced Raman Scattering. ACS NANO 2017; 11:4631-4640. [PMID: 28460167 DOI: 10.1021/acsnano.7b00258] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Microbes produce bioactive chemical compounds to influence the physiology and growth of their neighbors, and our understanding of their biological activities may be enhanced by our ability to visualize such molecules in vivo. We demonstrate here the application of surface-enhanced Raman scattering spectroscopy for simultaneous detection of quorum-sensing-regulated pyocyanin and violacein, produced respectively by Pseudomonas aeruginosa and Chromobacterium violaceum bacterial colonies, grown as a coculture on agar-based plasmonic substrates. Our plasmonic approach allowed us to visualize the expression and spatial distribution of the microbial metabolites in the coculture taking place as a result of interspecies chemical interactions. By combining surface-enhanced Raman scattering spectroscopy with analysis of gene expression we provide insight into the chemical interplay occurring between the interacting bacterial species. This highly sensitive, cost-effective, and easy to implement approach allows spatiotemporal imaging of cellular metabolites in live microbial colonies grown on agar with no need for sample preparation, thereby providing a powerful tool for the analysis of microbial chemotypes.
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Affiliation(s)
- Gustavo Bodelón
- Departamento de Química Física and Biomedical Research Center (CINBIO), Universidade de Vigo , 36310 Vigo, Spain
| | - Verónica Montes-García
- Departamento de Química Física and Biomedical Research Center (CINBIO), Universidade de Vigo , 36310 Vigo, Spain
| | - Celina Costas
- Departamento de Química Física and Biomedical Research Center (CINBIO), Universidade de Vigo , 36310 Vigo, Spain
| | - Ignacio Pérez-Juste
- Departamento de Química Física and Biomedical Research Center (CINBIO), Universidade de Vigo , 36310 Vigo, Spain
| | - Jorge Pérez-Juste
- Departamento de Química Física and Biomedical Research Center (CINBIO), Universidade de Vigo , 36310 Vigo, Spain
| | - Isabel Pastoriza-Santos
- Departamento de Química Física and Biomedical Research Center (CINBIO), Universidade de Vigo , 36310 Vigo, Spain
| | - Luis M Liz-Marzán
- Departamento de Química Física and Biomedical Research Center (CINBIO), Universidade de Vigo , 36310 Vigo, Spain
- Bionanoplasmonics Laboratory, CIC biomaGUNE , Paseo de Miramón 182, 20014 Donostia-San Sebastián, Spain
- Ikerbasque, Basque Foundation for Science , 48013 Bilbao, Spain
- Biomedical Research Networking Center in Bioengineering, Biomaterials, and Nanomedicine (CIBER-BBN) , 20014 Donostia-San Sebastián, Spain
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195
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Lee J, Lee I, Nam J, Hwang DS, Yeon KM, Kim J. Immobilization and Stabilization of Acylase on Carboxylated Polyaniline Nanofibers for Highly Effective Antifouling Application via Quorum Quenching. ACS APPLIED MATERIALS & INTERFACES 2017; 9:15424-15432. [PMID: 28414213 DOI: 10.1021/acsami.7b01528] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Acylase (AC) was immobilized and stabilized on carboxylated polyaniline nanofibers (cPANFs) for the development of antifouling nanobiocatalysts with high enzyme loading and stability. AC was immobilized via three different approaches: covalent attachment (CA), enzyme coating (EC), and magnetically separable enzyme precipitate coating (Mag-EPC). The enzyme activity per unit weight of cPANFs with Mag-EPC was 75 and 300 times higher than that of those with CA and EC, respectively, representing improved enzyme loading in the form of Mag-EPC. After incubation under shaking at 200 rpm for 20 days, Mag-EPC maintained 55% of its initial activity, whereas CA and EC showed 3 and 16% of their initial activities, respectively. The antifouling of highly loaded and stable Mag-EPC against the biofouling/biofilm formation of Pseudomonas aeruginosa was tested under static- and continuous-flow conditions. Biofilm formation in the presence of 40 μg/mL Mag-EPC under static condition was 5 times lower than that under control condition with no addition of Mag-EPC. Under continuous membrane filtration, Mag-EPC delayed the increase of transmembrane pressure (TMP) more effectively as the concentration of added Mag-EPC increased. When separating Mag-EPC and membranes in two different vessels under internal circulation of the culture solution, Mag-EPC maintained a higher permeability than the control with no Mag-EPC addition. It was also confirmed that the addition of Mag-EPC reduced the generation of N-acyl homoserine lactone (AHL) autoinducers. This result reveals that the inhibition of biofilm formation and biofouling in the presence of Mag-EPC is due to the hydrolysis of AHL autoinducers, catalyzed by the immobilized and stabilized AC in the form of Mag-EPC. Mag-EPC of AC with high enzyme loadings and improved stability has demonstrated its great potential as an antifouling agent by reducing biofilm formation and membrane biofouling based on "enzymatic quorum quenching" of autoinducers.
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Affiliation(s)
| | | | | | | | - Kyung-Min Yeon
- Construction Technology Team, Samsung C&T Corporation , Alpharium Bldg 1. 606-10, Daewang pangyo-Ro, Seongnam-si, Gyunggi-Do 13530, Republic of Korea
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196
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Uzelac G, Patel HK, Devescovi G, Licastro D, Venturi V. Quorum sensing and RsaM regulons of the rice pathogen Pseudomonas fuscovaginae. MICROBIOLOGY-SGM 2017; 163:765-777. [PMID: 28530166 DOI: 10.1099/mic.0.000454] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Pseudomonas fuscovaginae (Pfv) is an emerging plant pathogen causing sheath brown rot in rice, as well as diseases in other gramineae food crops including maize, sorghum and wheat. Pfv possesses two conserved N-acyl homoserine lactone (AHL) quorum sensing (QS) systems called PfvI/R and PfsI/R, which are repressed by RsaL and RsaM, respectively. The two systems are not hierarchically organized and are involved in plant virulence. In this study the AHL QS PfsI/R, PfvI/R and RsaM regulons were determined by transcriptomic analysis. The PfsI/R system regulates 98 genes, whereas 26 genes are regulated by the PfvI/R AHL QS system; only two genes are regulated by both systems. RsaM, on the other hand, regulates over 400 genes: 206 are negatively regulated and 260 are positively regulated. More than half of the genes controlled by the PfsI/R system and 65 % by the PfvI/R system are also part of the RsaM regulon; this is due to RsaM being involved in the regulation of both systems. It is concluded that the two QS systems regulate a unique set of genes and that RsaM is a global regulator mediating the expression of different genes through the two QS systems as well as genes independently of QS.
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Affiliation(s)
- Gordana Uzelac
- International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
| | - Hitendra Kumar Patel
- International Centre for Genetic Engineering and Biotechnology, Trieste, Italy.,Present address: CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad, India
| | - Giulia Devescovi
- International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
| | | | - Vittorio Venturi
- International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
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197
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González O, Ortíz-Castro R, Díaz-Pérez C, Díaz-Pérez AL, Magaña-Dueñas V, López-Bucio J, Campos-García J. Non-ribosomal Peptide Synthases from Pseudomonas aeruginosa Play a Role in Cyclodipeptide Biosynthesis, Quorum-Sensing Regulation, and Root Development in a Plant Host. MICROBIAL ECOLOGY 2017; 73:616-629. [PMID: 27900439 DOI: 10.1007/s00248-016-0896-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2016] [Accepted: 11/06/2016] [Indexed: 06/06/2023]
Abstract
Diverse molecules mediate cross-kingdom communication between bacteria and their eukaryotic partners and determine pathogenic or symbiotic relationships. N-acyl-L-homoserine lactone-dependent quorum-sensing signaling represses the biosynthesis of bacterial cyclodipeptides (CDPs) that act as auxin signal mimics in the host plant Arabidopsis thaliana. In this work, we performed bioinformatics, biochemical, and plant growth analyses to identify non-ribosomal peptide synthase (NRPS) proteins of Pseudomonas aeruginosa, which are involved in CDP synthesis. A reverse genetics strategy allowed the identification of the genes encoding putative multi-modular-NRPS (MM-NRPS). Mutations in these genes affected the synthesis of the CDPs cyclo(L-Pro-L-Val), cyclo(L-Pro-L-Leu), and cyclo(L-Pro-L-Tyr), while showing wild-type-like levels of virulence factors, such as violacein, elastase, and pyocyanin. When analyzing the bioactivity of purified, naturally produced CDPs, it was found that cyclo(L-Pro-L-Tyr) and cyclo(L-Pro-L-Val) were capable of antagonizing quorum-sensing-LasR (QS-LasR)-dependent signaling in a contrasting manner in the cell-free supernatants of the selected NRPS mutants, which showed QS induction. Using a bacteria-plant interaction system, we further show that the pvdJ, ambB, and pchE P. aeruginosa mutants failed to repress primary root growth, but improved root branching in A. thaliana seedlings. These results indicated that the CDP production in P. aeruginosa depended on the functional MM-NRPS, which influences quorum-sensing of bacteria and plays a role in root architecture remodeling.
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Affiliation(s)
- Omar González
- Laboratorio de Biotecnología Microbiana, Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Edif. B-3, Ciudad Universitaria, 58030, Morelia, Michoacán, México
| | - Randy Ortíz-Castro
- Laboratorio de Biología del Desarrollo Vegetal, Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Edif. A1´, Ciudad Universitaria, 58030, Morelia, Michoacán, México
- Instituto de Ecología A.C., Xalapa, Ver., México
| | - César Díaz-Pérez
- Depto. Ingeniería Agroindustrial, División de Ciencias de la Salud e Ingenierías, Universidad de Guanajuato, Salvatierra, Gto., México
| | - Alma L Díaz-Pérez
- Laboratorio de Biotecnología Microbiana, Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Edif. B-3, Ciudad Universitaria, 58030, Morelia, Michoacán, México
| | - Viridiana Magaña-Dueñas
- Laboratorio de Biología del Desarrollo Vegetal, Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Edif. A1´, Ciudad Universitaria, 58030, Morelia, Michoacán, México
| | - José López-Bucio
- Laboratorio de Biología del Desarrollo Vegetal, Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Edif. A1´, Ciudad Universitaria, 58030, Morelia, Michoacán, México
| | - Jesús Campos-García
- Laboratorio de Biotecnología Microbiana, Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Edif. B-3, Ciudad Universitaria, 58030, Morelia, Michoacán, México.
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198
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Zhou L, Zhang LH, Cámara M, He YW. The DSF Family of Quorum Sensing Signals: Diversity, Biosynthesis, and Turnover. Trends Microbiol 2017; 25:293-303. [DOI: 10.1016/j.tim.2016.11.013] [Citation(s) in RCA: 105] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Revised: 11/09/2016] [Accepted: 11/22/2016] [Indexed: 01/18/2023]
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199
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Bofinger M, de Sousa LS, Fontes JE, Marsaioli AJ. Diketopiperazines as Cross-Communication Quorum- Sensing Signals between Cronobacter sakazakii and Bacillus cereus. ACS OMEGA 2017; 2:1003-1008. [PMID: 30023625 PMCID: PMC6044783 DOI: 10.1021/acsomega.6b00513] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Accepted: 03/06/2017] [Indexed: 06/08/2023]
Abstract
Herein, we reveal a second quorum-sensing system produced by Cronobacter sakazakii. A cyclo(l-Pro-l-Leu) diketopiperazine, detected in pure and mixed cultures of C. sakazakii and Bacillus cereus explains the coexistence of both in the same industrial environments. The molecule was identified by gas chromatography-mass spectrometry (GC-MS), 1H, and 13C NMR, including 2D NMR (correlation spectroscopy, heteronuclear multiple bond correlation, and heteronuclear single quantum correlation), and the absolute configuration was compared with that of four synthetic standards produced by solid phase peptide synthesis using a chiral column on a GC-flame ionization detection. This article provides a new method to determine the absolute configuration of cyclo(Pro-Leu) diketopiperazine replacing the joint use of 1H NMR and Marfey's method.
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200
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Discovery of scmR as a global regulator of secondary metabolism and virulence in Burkholderia thailandensis E264. Proc Natl Acad Sci U S A 2017; 114:E2920-E2928. [PMID: 28320949 DOI: 10.1073/pnas.1619529114] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Bacteria produce a diverse array of secondary metabolites that have been invaluable in the clinic and in research. These metabolites are synthesized by dedicated biosynthetic gene clusters (BGCs), which assemble architecturally complex molecules from simple building blocks. The majority of BGCs in a given bacterium are not expressed under normal laboratory growth conditions, and our understanding of how they are silenced is in its infancy. Here, we have addressed this question in the Gram-negative model bacterium Burkholderia thailandensis E264 using genetic, transcriptomic, metabolomic, and chemical approaches. We report that a previously unknown, quorum-sensing-controlled LysR-type transcriptional regulator, which we name ScmR (for secondary metabolite regulator), serves as a global gatekeeper of secondary metabolism and a repressor of numerous BGCs. Transcriptionally, we find that 13 of the 20 BGCs in B. thailandensis are significantly (threefold or more) up- or down-regulated in a scmR deletion mutant (ΔscmR) Metabolically, the ΔscmR strain displays a hyperactive phenotype relative to wild type and overproduces a number of compound families by 18- to 210-fold, including the silent virulence factor malleilactone. Accordingly, the ΔscmR mutant is hypervirulent both in vitro and in a Caenorhabditis elegans model in vivo. Aside from secondary metabolism, ScmR also represses biofilm formation and transcriptionally activates ATP synthesis and stress response. Collectively, our data suggest that ScmR is a pleiotropic regulator of secondary metabolism, virulence, biofilm formation, and other stationary phase processes. A model for how the interplay of ScmR with pathway-specific transcriptional regulators coordinately silences virulence factor production is proposed.
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