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Li Y, Wang H, Xu C, Sun SH, Xiao K, Huang X. Two strategies of stubborn biofouling strains surviving from NaClO membrane cleaning: EPS shielding and/or quorum sensing. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 838:156421. [PMID: 35660590 DOI: 10.1016/j.scitotenv.2022.156421] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 05/26/2022] [Accepted: 05/30/2022] [Indexed: 06/15/2023]
Abstract
The declined performance of repeated chemically-enhanced-backwashing (CEB) seriously hampered the sustainable operation of membrane bioreactor (MBR) in long-term, and could be partially attributed to the strengthened anti-cleaning properties of residual stubborn microbes. Although plenty of research has been done towards either the model strains or the whole post-CEB microbial community, little was known about the resisting behavior of practical stubborn strains when confronting oxidative stresses induced by NaClO. Hence, this study isolated 21 strains from samples in a large-scale MBR plant with routine CEB treatment. To unravel how they survive and affect membrane fouling, their anti-oxidation ability, fouling potential and quorum sensing (QS) effect before and after NaClO stimuli were evaluated. The composition and molecular weight distribution of extracellular polymeric substance (EPS) were also investigated to understand their roles during the anti-CEB process. It was found that typical stubborn strains tended to secrete more EPS as protective shields, where polysaccharides (especially the ones >1 kDa) made major contribution. However, sometimes EPS could not well resist the stimuli, with consequent low survival rate and high intracellular ROS level. Under such circumstances, stubborn strains would rather choose to be sensitive with surged QS level and quick population regrowth to maintain vitality under the oxidative stresses. Both strategies aggravated biofouling and eventually enhanced the anti-cleaning properties of biofilm.
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Affiliation(s)
- Yufang Li
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Han Wang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China; Beijing OriginWater Membrane Technology Co., Ltd., Product and Technology Center, Beijing 101407, China
| | - Chenyang Xu
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Shih-Han Sun
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Kang Xiao
- Beijing Yanshan Earth Critical Zone National Research Station, College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 101408, China.
| | - Xia Huang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China; Research and Application Center for Membrane Technology, School of Environment, Tsinghua University, Beijing 100084, China.
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2
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Abstract
The nasopharynx and the skin are the major oxygen-rich anatomical sites for colonization by the human pathogen Streptococcus pyogenes (group A Streptococcus [GAS]). To establish infection, GAS must survive oxidative stress generated during aerobic metabolism and the release of reactive oxygen species (ROS) by host innate immune cells. Glutathione is the major host antioxidant molecule, while GAS is glutathione auxotrophic. Here, we report the molecular characterization of the ABC transporter substrate binding protein GshT in the GAS glutathione salvage pathway. We demonstrate that glutathione uptake is critical for aerobic growth of GAS and that impaired import of glutathione induces oxidative stress that triggers enhanced production of the reducing equivalent NADPH. Our results highlight the interrelationship between glutathione assimilation, carbohydrate metabolism, virulence factor production, and innate immune evasion. Together, these findings suggest an adaptive strategy employed by extracellular bacterial pathogens to exploit host glutathione stores for their own benefit.
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3
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Baty JJ, Huffines JT, Stoner SN, Scoffield JA. A Commensal Streptococcus Dysregulates the Pseudomonas aeruginosa Nitrosative Stress Response. Front Cell Infect Microbiol 2022; 12:817336. [PMID: 35619650 PMCID: PMC9127344 DOI: 10.3389/fcimb.2022.817336] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 02/28/2022] [Indexed: 11/13/2022] Open
Abstract
Chronic infections in the cystic fibrosis (CF) airway are composed of both pathogenic and commensal bacteria. However, chronic Pseudomonas aeruginosa infections are the leading cause of lung deterioration in individuals with CF. Interestingly, oral commensals can translocate to the CF lung and their presence is associated with improved lung function, presumably due to their ability to antagonize P. aeruginosa. We have previously shown that one commensal, Streptococcus parasanguinis, produces hydrogen peroxide that reacts with nitrite to generate reactive nitrogen intermediates (RNI) which inhibit P. aeruginosa growth. In this study, we sought to understand the global impact of commensal-mediated RNI on the P. aeruginosa transcriptome. RNA sequencing analysis revealed that S. parasanguinis and nitrite-mediated RNI dysregulated expression of denitrification genes in a CF isolate of P. aeruginosa compared to when this isolate was only exposed to S. parasanguinis. Further, loss of a nitric oxide reductase subunit (norB) rendered an acute P. aeruginosa isolate more susceptible to S. parasanguinis-mediated RNI. Additionally, S. parasanguinis-mediated RNI inactivated P. aeruginosa aconitase activity. Lastly, we report that P. aeruginosa isolates recovered from CF individuals are uniquely hypersensitive to S. parasanguinis-mediated RNI compared to acute infection or environmental P. aeruginosa isolates. These findings illustrate that S. parasanguinis hinders the ability of P. aeruginosa to respond to RNI, which potentially prevents P. aeruginosa CF isolates from resisting commensal and host-induced RNI in the CF airway.
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Xie Y, Chen J, Wang B, Peng AY, Mao ZW, Xia W. Inhibition of Quorum-Sensing Regulator from Pseudomonas aeruginosa Using a Flavone Derivative. Molecules 2022; 27:molecules27082439. [PMID: 35458637 PMCID: PMC9031925 DOI: 10.3390/molecules27082439] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 03/31/2022] [Accepted: 04/06/2022] [Indexed: 01/19/2023] Open
Abstract
Quorum sensing (QS) is a cell-to-cell communication process that controls bacterial collective behaviors. The QS network regulates and coordinates bacterial virulence factor expression, antibiotic resistance and biofilm formation. Therefore, inhibition of the QS system is an effective strategy to suppress the bacterial virulence. Herein, we identify a phosphate ester derivative of chrysin as a potent QS inhibitor of the human pathogen Pseudomonas aeruginosa (P. aeruginosa) using a designed luciferase reporter assay. In vitro biochemical analysis shows that the chrysin derivative binds to the bacterial QS regulator LasR and abrogates its DNA-binding capability. In particular, the derivative exhibits higher anti-virulence activity compared to the parent molecule. All the results reveal the potential application of flavone derivative as an anti-virulence compound to combat the infectious diseases caused by P. aeruginosa.
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Affiliation(s)
- Yanxuan Xie
- School of Chemistry, Sun Yat-Sen University, Guangzhou 510275, China; (Y.X.); (J.C.); (B.W.); (A.-Y.P.)
- MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, Sun Yat-Sen University, Guangzhou 510275, China
| | - Jingxin Chen
- School of Chemistry, Sun Yat-Sen University, Guangzhou 510275, China; (Y.X.); (J.C.); (B.W.); (A.-Y.P.)
- MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, Sun Yat-Sen University, Guangzhou 510275, China
| | - Bo Wang
- School of Chemistry, Sun Yat-Sen University, Guangzhou 510275, China; (Y.X.); (J.C.); (B.W.); (A.-Y.P.)
| | - Ai-Yun Peng
- School of Chemistry, Sun Yat-Sen University, Guangzhou 510275, China; (Y.X.); (J.C.); (B.W.); (A.-Y.P.)
| | - Zong-Wan Mao
- School of Chemistry, Sun Yat-Sen University, Guangzhou 510275, China; (Y.X.); (J.C.); (B.W.); (A.-Y.P.)
- MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, Sun Yat-Sen University, Guangzhou 510275, China
- Correspondence: (Z.-W.M.); (W.X.)
| | - Wei Xia
- School of Chemistry, Sun Yat-Sen University, Guangzhou 510275, China; (Y.X.); (J.C.); (B.W.); (A.-Y.P.)
- MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, Sun Yat-Sen University, Guangzhou 510275, China
- Correspondence: (Z.-W.M.); (W.X.)
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5
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OFF-switching property of quorum sensor LuxR via As(III)-induced insoluble form. J Biosci Bioeng 2022; 133:335-339. [PMID: 35120813 DOI: 10.1016/j.jbiosc.2021.12.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 12/23/2021] [Accepted: 12/26/2021] [Indexed: 11/21/2022]
Abstract
Whole-cell sensors for arsenite detection have been developed exclusively based on the natural arsenite (As(III)) sensory protein ArsR for arsenic metabolism. This study reports that the quorum-sensing LuxR/Plux system from Vibrio fischeri, which is completely unrelated to arsenic metabolism, responds to As(III) in a dose-dependent manner. Due to as many as 9 cysteine residues, which has a high binding affinity with As(III), LuxR underwent As(III)-induced insoluble form, thereby reducing its effective cellular concentration. Accordingly, the expression level of green fluorescent protein under the control of Plux gradually decreased with increasing As(III) concentration in the medium. This is a novel As(III)-detection system that has never been proposed before, with a unique ON-to-OFF transfer function.
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6
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Xuan G, Lv C, Xu H, Li K, Liu H, Xia Y, Xun L. Sulfane Sulfur Regulates LasR-Mediated Quorum Sensing and Virulence in Pseudomonas aeruginosa PAO1. Antioxidants (Basel) 2021; 10:antiox10091498. [PMID: 34573130 PMCID: PMC8469610 DOI: 10.3390/antiox10091498] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Revised: 09/10/2021] [Accepted: 09/18/2021] [Indexed: 12/18/2022] Open
Abstract
Sulfane sulfur, such as inorganic and organic polysulfide (HSn- and RSn-, n > 2), is a common cellular component, produced either from hydrogen sulfide oxidation or cysteine metabolism. In Pseudomonas aeruginosa PAO1, LasR is a quorum sensing master regulator. After binding its autoinducer, LasR binds to its target DNA to activate the transcription of a suite of genes, including virulence factors. Herein, we report that the production of hydrogen sulfide and sulfane sulfur were positively correlated in P. aeruginosa PAO1, and sulfane sulfur was able to modify LasR, which generated Cys188 persulfide and trisulfide and produced a pentasulfur link between Cys201 and Cys203. The modifications did not affect LasR binding to its target DNA site, but made it several-fold more effective than unmodified LasR in activating transcription in both in vitro and in vivo assays. On the contrary, H2O2 inactivates LasR via producing a disulfide bond between Cys201 and Cys203. P. aeruginosa PAO1 had a high cellular sulfane sulfur and high LasR activity in the mid log phase and early stationary phase, but a low sulfane sulfur and low LasR activity in the declination phase. Thus, sulfane sulfur is a new signaling factor in the bacterium, adding another level of control over LasR-mediated quorum sensing and turning down the activity in old cells.
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Affiliation(s)
- Guanhua Xuan
- State Key Laboratory of Microbial Technology, Shandong University, 72 Binhai Road, Qingdao 266237, China; (G.X.); (C.L.); (H.X.); (K.L.); (H.L.)
| | - Chuanjuan Lv
- State Key Laboratory of Microbial Technology, Shandong University, 72 Binhai Road, Qingdao 266237, China; (G.X.); (C.L.); (H.X.); (K.L.); (H.L.)
| | - Huangwei Xu
- State Key Laboratory of Microbial Technology, Shandong University, 72 Binhai Road, Qingdao 266237, China; (G.X.); (C.L.); (H.X.); (K.L.); (H.L.)
| | - Kai Li
- State Key Laboratory of Microbial Technology, Shandong University, 72 Binhai Road, Qingdao 266237, China; (G.X.); (C.L.); (H.X.); (K.L.); (H.L.)
| | - Huaiwei Liu
- State Key Laboratory of Microbial Technology, Shandong University, 72 Binhai Road, Qingdao 266237, China; (G.X.); (C.L.); (H.X.); (K.L.); (H.L.)
| | - Yongzhen Xia
- State Key Laboratory of Microbial Technology, Shandong University, 72 Binhai Road, Qingdao 266237, China; (G.X.); (C.L.); (H.X.); (K.L.); (H.L.)
- Correspondence: (Y.X.); (L.X.); Tel.: +86-532-5863-1572 (Y.X.); +1-509-335-2787 (L.X.)
| | - Luying Xun
- State Key Laboratory of Microbial Technology, Shandong University, 72 Binhai Road, Qingdao 266237, China; (G.X.); (C.L.); (H.X.); (K.L.); (H.L.)
- School of Molecular Biosciences, Washington State University, Pullman, WA 99164-7520, USA
- Correspondence: (Y.X.); (L.X.); Tel.: +86-532-5863-1572 (Y.X.); +1-509-335-2787 (L.X.)
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7
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Oxidative Stress Response in Pseudomonas aeruginosa. Pathogens 2021; 10:pathogens10091187. [PMID: 34578219 PMCID: PMC8466533 DOI: 10.3390/pathogens10091187] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 09/06/2021] [Accepted: 09/08/2021] [Indexed: 12/17/2022] Open
Abstract
Pseudomonas aeruginosa is a Gram-negative environmental and human opportunistic pathogen highly adapted to many different environmental conditions. It can cause a wide range of serious infections, including wounds, lungs, the urinary tract, and systemic infections. The high versatility and pathogenicity of this bacterium is attributed to its genomic complexity, the expression of several virulence factors, and its intrinsic resistance to various antimicrobials. However, to thrive and establish infection, P. aeruginosa must overcome several barriers. One of these barriers is the presence of oxidizing agents (e.g., hydrogen peroxide, superoxide, and hypochlorous acid) produced by the host immune system or that are commonly used as disinfectants in a variety of different environments including hospitals. These agents damage several cellular molecules and can cause cell death. Therefore, bacteria adapt to these harsh conditions by altering gene expression and eliciting several stress responses to survive under oxidative stress. Here, we used PubMed to evaluate the current knowledge on the oxidative stress responses adopted by P. aeruginosa. We will describe the genes that are often differently expressed under oxidative stress conditions, the pathways and proteins employed to sense and respond to oxidative stress, and how these changes in gene expression influence pathogenicity and the virulence of P. aeruginosa. Understanding these responses and changes in gene expression is critical to controlling bacterial pathogenicity and developing new therapeutic agents.
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8
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Vetrivel A, Natchimuthu S, Subramanian V, Murugesan R. High-Throughput Virtual Screening for a New Class of Antagonist Targeting LasR of Pseudomonas aeruginosa. ACS OMEGA 2021; 6:18314-18324. [PMID: 34308062 PMCID: PMC8296597 DOI: 10.1021/acsomega.1c02191] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 06/16/2021] [Indexed: 05/28/2023]
Abstract
Pseudomonas aeruginosa, an opportunistic human pathogen, causes fatal effects in patients with cystic fibrosis and immunocompromised individuals and leads to around 1000 deaths annually. The quorum sensing mechanism of P. aeruginosa plays a major role in promoting biofilm formation and expression of virulent genes. Hence, quorum sensing inhibition is a promising novel approach to treat these bacterial infections as these organisms show a wide range of antibiotic resistance. Among the interconnected quorum sensing network of P. aeruginosa, targeting the las system is of increased interest as its principal receptor protein LasR is the earliest activated gene. It is also shown to be involved in the regulation of other virulence-associated genes. In this study, we have applied high-throughput virtual screening, an in silico computational method to identify a new class of LasR inhibitors that could serve as potent antagonists to treat P. aeruginosa-associated infections. Three-tire structure-based virtual screening was performed on the Schrödinger small molecule database, which resulted in 12 top hit compounds with docking scores lesser than -11.0 kcal/mol. Three of these best-scored compounds CACPD2011a-0001928786 (C1), CACPD2011a-0001927437 (C2), and CACPD2011a-0000896051 (C3) were further analyzed. The binding free energies of these compounds in complex with the target protein LasR (3IX4) were evaluated, and the pharmacokinetic properties were determined. The stability of the docked complexes was assessed by running a molecular dynamics simulation for 100 ns. Molecular dynamics simulation analysis revealed that all three compounds were found to be in stable contact with the protein over the entire simulation period. The antagonistic effect of these compounds was validated using the LasR reporter gene assay in the presence of acyl homoserine lactone. Significant reduction in the β-galactosidase enzyme activity was achieved at 100 nM concentration for all three compounds pursued. Hence, the present study provides strong evidence that these three compounds could serve as quorum sensing inhibitors of P. aeruginosa LasR protein and can be a probable candidate to treat Pseudomonas-associated infections.
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Affiliation(s)
- Aishwarya Vetrivel
- Department
of Biochemistry, Biotechnology and Bioinformatics, Avinashilingam Institute for Home Science and Higher Education for
Women, Coimbatore 641043, Tamil Nadu, India
| | - Santhi Natchimuthu
- Department
of Biochemistry, Biotechnology and Bioinformatics, Avinashilingam Institute for Home Science and Higher Education for
Women, Coimbatore 641043, Tamil Nadu, India
| | | | - Rajeswari Murugesan
- Department
of Biochemistry, Biotechnology and Bioinformatics, Avinashilingam Institute for Home Science and Higher Education for
Women, Coimbatore 641043, Tamil Nadu, India
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9
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Shah M, Taylor VL, Bona D, Tsao Y, Stanley SY, Pimentel-Elardo SM, McCallum M, Bondy-Denomy J, Howell PL, Nodwell JR, Davidson AR, Moraes TF, Maxwell KL. A phage-encoded anti-activator inhibits quorum sensing in Pseudomonas aeruginosa. Mol Cell 2021; 81:571-583.e6. [PMID: 33412111 DOI: 10.1016/j.molcel.2020.12.011] [Citation(s) in RCA: 64] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 11/19/2020] [Accepted: 12/03/2020] [Indexed: 11/28/2022]
Abstract
The arms race between bacteria and phages has led to the evolution of diverse anti-phage defenses, several of which are controlled by quorum-sensing pathways. In this work, we characterize a quorum-sensing anti-activator protein, Aqs1, found in Pseudomonas phage DMS3. We show that Aqs1 inhibits LasR, the master regulator of quorum sensing, and present the crystal structure of the Aqs1-LasR complex. The 69-residue Aqs1 protein also inhibits PilB, the type IV pilus assembly ATPase protein, which blocks superinfection by phages that require the pilus for infection. This study highlights the remarkable ability of small phage proteins to bind multiple host proteins and disrupt key biological pathways. As quorum sensing influences various anti-phage defenses, Aqs1 provides a mechanism by which infecting phages might simultaneously dampen multiple defenses. Because quorum-sensing systems are broadly distributed across bacteria, this mechanism of phage counter-defense may play an important role in phage-host evolutionary dynamics.
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Affiliation(s)
- Megha Shah
- Department of Biochemistry, University of Toronto, MaRS West Tower, 661 University Avenue, Toronto, ON M5G 1M1, Canada
| | - Véronique L Taylor
- Department of Biochemistry, University of Toronto, MaRS West Tower, 661 University Avenue, Toronto, ON M5G 1M1, Canada
| | - Diane Bona
- Department of Biochemistry, University of Toronto, MaRS West Tower, 661 University Avenue, Toronto, ON M5G 1M1, Canada
| | - Yvonne Tsao
- Department of Biochemistry, University of Toronto, MaRS West Tower, 661 University Avenue, Toronto, ON M5G 1M1, Canada
| | - Sabrina Y Stanley
- Department of Molecular Genetics, University of Toronto, MaRS West Tower, 661 University Avenue, Toronto, ON M5G 1M1, Canada
| | - Sheila M Pimentel-Elardo
- Department of Biochemistry, University of Toronto, MaRS West Tower, 661 University Avenue, Toronto, ON M5G 1M1, Canada
| | - Matthew McCallum
- Department of Biochemistry, University of Toronto, MaRS West Tower, 661 University Avenue, Toronto, ON M5G 1M1, Canada; Program in Molecular Structure & Function, Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - Joseph Bondy-Denomy
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94143, USA
| | - P Lynne Howell
- Department of Biochemistry, University of Toronto, MaRS West Tower, 661 University Avenue, Toronto, ON M5G 1M1, Canada; Program in Molecular Structure & Function, Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - Justin R Nodwell
- Department of Biochemistry, University of Toronto, MaRS West Tower, 661 University Avenue, Toronto, ON M5G 1M1, Canada
| | - Alan R Davidson
- Department of Biochemistry, University of Toronto, MaRS West Tower, 661 University Avenue, Toronto, ON M5G 1M1, Canada; Department of Molecular Genetics, University of Toronto, MaRS West Tower, 661 University Avenue, Toronto, ON M5G 1M1, Canada
| | - Trevor F Moraes
- Department of Biochemistry, University of Toronto, MaRS West Tower, 661 University Avenue, Toronto, ON M5G 1M1, Canada.
| | - Karen L Maxwell
- Department of Biochemistry, University of Toronto, MaRS West Tower, 661 University Avenue, Toronto, ON M5G 1M1, Canada.
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10
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Azimi S, Roberts AEL, Peng S, Weitz JS, McNally A, Brown SP, Diggle SP. Allelic polymorphism shapes community function in evolving Pseudomonas aeruginosa populations. ISME JOURNAL 2020; 14:1929-1942. [PMID: 32341475 DOI: 10.1038/s41396-020-0652-0] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 03/23/2020] [Accepted: 03/31/2020] [Indexed: 12/31/2022]
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen that chronically infects the lungs of individuals with cystic fibrosis (CF) by forming antibiotic-resistant biofilms. Emergence of phenotypically diverse isolates within CF P. aeruginosa populations has previously been reported; however, the impact of heterogeneity on social behaviors and community function is poorly understood. Here we describe how this heterogeneity impacts on behavioral traits by evolving the strain PAO1 in biofilms grown in a synthetic sputum medium for 50 days. We measured social trait production and antibiotic tolerance, and used a metagenomic approach to analyze and assess genomic changes over the duration of the evolution experiment. We found that (i) evolutionary trajectories were reproducible in independently evolving populations; (ii) over 60% of genomic diversity occurred within the first 10 days of selection. We then focused on quorum sensing (QS), a well-studied P. aeruginosa trait that is commonly mutated in strains isolated from CF lungs. We found that at the population level, (i) evolution in sputum medium selected for decreased the production of QS and QS-dependent traits; (ii) there was a significant correlation between lasR mutant frequency, the loss of protease, and the 3O-C12-HSL signal, and an increase in resistance to clinically relevant β-lactam antibiotics, despite no previous antibiotic exposure. Overall, our findings provide insights into the effect of allelic polymorphism on community functions in diverse P. aeruginosa populations. Further, we demonstrate that P. aeruginosa population and evolutionary dynamics can impact on traits important for virulence and can lead to increased tolerance to β-lactam antibiotics.
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Affiliation(s)
- Sheyda Azimi
- Center for Microbial Dynamics & Infection, Georgia Institute of Technology, Atlanta, GA, USA.,School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - Aled E L Roberts
- Microbiology & Infectious Diseases Group, Institute of Life Science, Swansea University Medical School, Swansea, UK
| | - Shengyun Peng
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - Joshua S Weitz
- Center for Microbial Dynamics & Infection, Georgia Institute of Technology, Atlanta, GA, USA.,School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA.,School of Physics, Georgia Institute of Technology, Atlanta, GA, USA
| | - Alan McNally
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Samuel P Brown
- Center for Microbial Dynamics & Infection, Georgia Institute of Technology, Atlanta, GA, USA.,School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - Stephen P Diggle
- Center for Microbial Dynamics & Infection, Georgia Institute of Technology, Atlanta, GA, USA. .,School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA.
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11
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Modulation of Pseudomonas aeruginosa Quorum Sensing by Glutathione. J Bacteriol 2019; 201:JB.00685-18. [PMID: 30782628 DOI: 10.1128/jb.00685-18] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Accepted: 02/07/2019] [Indexed: 01/24/2023] Open
Abstract
Pseudomonas aeruginosa uses quorum sensing (QS) to regulate the production of a battery of secreted products. At least some of these products are shared among the population and serve as public goods. When P. aeruginosa is grown on casein as the sole carbon and energy source, the QS-induced extracellular protease elastase is required for growth. We isolated a P. aeruginosa variant, which showed increased production of QS-induced factors after repeated transfers in casein broth. This variant, P. aeruginosa QS*, had a mutation in the glutathione synthesis gene gshA We describe several experiments that show a gshA coding variant and glutathione affect the QS response. The P. aeruginosa QS transcription factor LasR has a redox-sensitive cysteine (C79). We report that GshA variant cells with a LasR C79S substitution show a similar QS response to that of wild-type P. aeruginosa Surprisingly, it is not LasR but the QS transcription factor RhlR that is more active in bacteria containing the variant gshA Our results demonstrate that QS integrates information about cell density and the cellular redox state via glutathione levels.IMPORTANCE Pseudomonas aeruginosa and other bacteria coordinate group behaviors using a chemical communication system called quorum sensing (QS). The QS system of P. aeruginosa is complex, with several regulators and signals. We show that decreased levels of glutathione lead to increased gene activation in P. aeruginosa, which did not occur in a strain carrying the redox-insensitive variant of a transcription factor. The ability of P. aeruginosa QS transcription factors to integrate information about cell density and cellular redox state shows these transcription factors can fine-tune levels of the gene products they control in response to at least two types of signals or cues.
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12
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de Almeida FA, Carneiro DG, de Oliveira Mendes TA, Barros E, Pinto UM, de Oliveira LL, Vanetti MCD. N-dodecanoyl-homoserine lactone influences the levels of thiol and proteins related to oxidation-reduction process in Salmonella. PLoS One 2018; 13:e0204673. [PMID: 30304064 PMCID: PMC6179229 DOI: 10.1371/journal.pone.0204673] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 09/12/2018] [Indexed: 01/09/2023] Open
Abstract
Quorum sensing is a cell-cell communication mechanism mediated by chemical signals that leads to differential gene expression in response to high population density. Salmonella is unable to synthesize the autoinducer-1 (AI-1), N-acyl homoserine lactone (AHL), but is able to recognize AHLs produced by other microorganisms through SdiA protein. This study aimed to evaluate the fatty acid and protein profiles of Salmonella enterica serovar Enteritidis PT4 578 throughout time of cultivation in the presence of AHL. The presence of N-dodecanoyl-homoserine lactone (C12-HSL) altered the fatty acid and protein profiles of Salmonella cultivated during 4, 6, 7, 12 and 36 h in anaerobic condition. The profiles of Salmonella Enteritidis at logarithmic phase of growth (4 h of cultivation), in the presence of C12-HSL, were similar to those of cells at late stationary phase (36 h). In addition, there was less variation in both protein and fatty acid profiles along growth, suggesting that this quorum sensing signal anticipated a stationary phase response. The presence of C12-HSL increased the abundance of thiol related proteins such as Tpx, Q7CR42, Q8ZP25, YfgD, AhpC, NfsB, YdhD and TrxA, as well as the levels of free cellular thiol after 6 h of cultivation, suggesting that these cells have greater potential to resist oxidative stress. Additionally, the LuxS protein which synthesizes the AI-2 signaling molecule was differentially abundant in the presence of C12-HSL. The NfsB protein had its abundance increased in the presence of C12-HSL at all evaluated times, which is a suggestion that the cells may be susceptible to the action of nitrofurans or that AHLs present some toxicity. Overall, the presence of C12-HSL altered important pathways related to oxidative stress and stationary phase response in Salmonella.
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Affiliation(s)
| | | | | | - Edvaldo Barros
- Núcleo de Análise de Biomoléculas, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil
| | - Uelinton Manoel Pinto
- Food Research Center, Department of Food and Experimental Nutrition, Faculty of Pharmaceutical Sciences, Universidade de São Paulo, São Paulo, São Paulo, Brazil
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Suneby EG, Herndon LR, Schneider TL. Pseudomonas aeruginosa LasR·DNA Binding Is Directly Inhibited by Quorum Sensing Antagonists. ACS Infect Dis 2017; 3:183-189. [PMID: 28075113 DOI: 10.1021/acsinfecdis.6b00163] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Inhibition of quorum sensing in Pseudomonas aeruginosa is of interest as a possible antivirulence strategy for this pathogenic bacterium. The LasR regulator protein is important in coordinating gene expression in response to quorum sensing signaling molecules. One predominant strategy for LasR inhibition is the development of small-molecule antagonists that mimic the native autoinducer, though the mechanism by which they inactivate LasR is not known. This work reveals that multiple antagonists function by binding to and stabilizing LasR in a conformation that renders it unable to bind DNA. Further analysis of purified LasR complexed with known antagonists indicates that DNA binding can be recovered with the addition of native autoinducer, providing insights into the reversibility of ligand binding for this transcription factor. This in vitro assay could be used to assess future promising antagonists and complements existing cell-based reporter assays.
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Affiliation(s)
- Emma G. Suneby
- Department of Chemistry, Connecticut College, New London, Connecticut 06320, United States
| | - Leslie R. Herndon
- Department
of Chemistry, Smith College, Northampton, Massachusetts 01063, United States
| | - Tanya L. Schneider
- Department of Chemistry, Connecticut College, New London, Connecticut 06320, United States
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14
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Chen Z, Wang X, Yang F, Hu Q, Tong H, Dong X. Molecular Insights into Hydrogen Peroxide-sensing Mechanism of the Metalloregulator MntR in Controlling Bacterial Resistance to Oxidative Stresses. J Biol Chem 2017; 292:5519-5531. [PMID: 28223356 DOI: 10.1074/jbc.m116.764126] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Revised: 01/28/2017] [Indexed: 11/06/2022] Open
Abstract
Manganese contributes to anti-oxidative stress particularly in catalase-devoid bacteria, and DtxR family metalloregulators, through sensing cellular Mn2+ content, regulate its homeostasis. Here, we show that metalloregulator MntR (So-MntR) functions dually as Mn2+ and H2O2 sensors in mediating H2O2 resistance by an oral streptococcus. H2O2 disrupted So-MntR binding to Mn2+ transporter mntABC promoter and induced disulfide-linked dimerization of the protein. Mass spectrometry identified Cys-11/Cys-156 and Cys-11/Cys-11 disulfide-linked peptides in H2O2-treated So-MntR. Site mutagenesis of Cys-11 and Cys-156 and particularly Cys-11 abolished H2O2-induced disulfide-linked dimers and weakened H2O2 damage on So-MntR binding, indicating that H2O2 inactivates So-MntR via disulfide-linked dimerization. So-MntR C123S mutant was extremely sensitive to H2O2 oxidization in dimerization/oligomerization, probably because the mutagenesis caused a conformational change that facilitates Cys-11/Cys-156 disulfide linkage. Intermolecular Cys-11/Cys-11 disulfide was detected in C123S/C156S double mutant. Redox Western blot detected So-MntR oligomers in air-exposed cells but remarkably decreased upon H2O2 pulsing, suggesting a proteolysis of the disulfide-linked So-MntR oligomers. Remarkably, elevated C11S and C156S but much lower C123S proteins were detected in H2O2-pulsed cells, confirming Cys-11 and Cys-156 contributed to H2O2-induced oligomerization and degradation. Accordingly, in the C11S and C156S mutants, expression of mntABC and cellular Mn2+ decreased, but H2O2 susceptibility increased. In the C123S mutant, increased mntABC expression, cellular Mn2+ content, and manganese-mediated H2O2 survival were determined. Given the wide distribution of Cys-11 in streptococcal DtxR-like metalloregulators, the disclosed redox regulatory function and mechanism of So-MntR can be employed by the DtxR family proteins in bacterial resistance to oxidative stress.
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Affiliation(s)
- Zhaoyuan Chen
- From the State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, No.1 Beichen West Road, Chaoyang District, Beijing 100101, China.,School of Life Sciences, University of Chinese Academy of Sciences, No.19A Yuquan Road, Shijingshan District, Beijing 100049, China, and
| | - Xinhui Wang
- From the State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, No.1 Beichen West Road, Chaoyang District, Beijing 100101, China.,School of Life Sciences, University of Chinese Academy of Sciences, No.19A Yuquan Road, Shijingshan District, Beijing 100049, China, and
| | - Fan Yang
- MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Qingqing Hu
- From the State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, No.1 Beichen West Road, Chaoyang District, Beijing 100101, China.,School of Life Sciences, University of Chinese Academy of Sciences, No.19A Yuquan Road, Shijingshan District, Beijing 100049, China, and
| | - Huichun Tong
- From the State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, No.1 Beichen West Road, Chaoyang District, Beijing 100101, China, .,School of Life Sciences, University of Chinese Academy of Sciences, No.19A Yuquan Road, Shijingshan District, Beijing 100049, China, and
| | - Xiuzhu Dong
- From the State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, No.1 Beichen West Road, Chaoyang District, Beijing 100101, China, .,School of Life Sciences, University of Chinese Academy of Sciences, No.19A Yuquan Road, Shijingshan District, Beijing 100049, China, and
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