1
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Novak JK, Gardner JG. Current models in bacterial hemicellulase-encoding gene regulation. Appl Microbiol Biotechnol 2024; 108:39. [PMID: 38175245 PMCID: PMC10766802 DOI: 10.1007/s00253-023-12977-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 12/06/2023] [Accepted: 12/07/2023] [Indexed: 01/05/2024]
Abstract
The discovery and characterization of bacterial carbohydrate-active enzymes is a fundamental component of biotechnology innovation, particularly for renewable fuels and chemicals; however, these studies have increasingly transitioned to exploring the complex regulation required for recalcitrant polysaccharide utilization. This pivot is largely due to the current need to engineer and optimize enzymes for maximal degradation in industrial or biomedical applications. Given the structural simplicity of a single cellulose polymer, and the relatively few enzyme classes required for complete bioconversion, the regulation of cellulases in bacteria has been thoroughly discussed in the literature. However, the diversity of hemicelluloses found in plant biomass and the multitude of carbohydrate-active enzymes required for their deconstruction has resulted in a less comprehensive understanding of bacterial hemicellulase-encoding gene regulation. Here we review the mechanisms of this process and common themes found in the transcriptomic response during plant biomass utilization. By comparing regulatory systems from both Gram-negative and Gram-positive bacteria, as well as drawing parallels to cellulase regulation, our goals are to highlight the shared and distinct features of bacterial hemicellulase-encoding gene regulation and provide a set of guiding questions to improve our understanding of bacterial lignocellulose utilization. KEY POINTS: • Canonical regulatory mechanisms for bacterial hemicellulase-encoding gene expression include hybrid two-component systems (HTCS), extracytoplasmic function (ECF)-σ/anti-σ systems, and carbon catabolite repression (CCR). • Current transcriptomic approaches are increasingly being used to identify hemicellulase-encoding gene regulatory patterns coupled with computational predictions for transcriptional regulators. • Future work should emphasize genetic approaches to improve systems biology tools available for model bacterial systems and emerging microbes with biotechnology potential. Specifically, optimization of Gram-positive systems will require integration of degradative and fermentative capabilities, while optimization of Gram-negative systems will require bolstering the potency of lignocellulolytic capabilities.
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Affiliation(s)
- Jessica K Novak
- Department of Biological Sciences, University of Maryland - Baltimore County, Baltimore, MD, USA
| | - Jeffrey G Gardner
- Department of Biological Sciences, University of Maryland - Baltimore County, Baltimore, MD, USA.
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2
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Li C, Wu J, Wang P, Zhang D, Zhu L, Gao Y, Wang W, Sun H. Effect of Halomonas titanicae on fluctuating water-line corrosion of EH40 steel. Bioelectrochemistry 2024; 158:108703. [PMID: 38599139 DOI: 10.1016/j.bioelechem.2024.108703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2024] [Revised: 02/28/2024] [Accepted: 04/03/2024] [Indexed: 04/12/2024]
Abstract
The fluctuating water-line corrosion of EH40 steel in sterile and biotic media was investigated with a wire beam electrode. When the coupons were partially immersed in the sterile medium, the position of the low water-line acted as the cathodic zone and the area below the low water-line constantly served as the main anodic zone. The thin electrolyte layers with uneven thickness promoted the galvanic current of the region below the low water-line. Different from the sterile environment, the metabolism of Halomonas titanica with oxygen as the final electron acceptor reduced the dissolved oxygen concentration, which resulted in the position of the low water-line acting as the anodic zone.
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Affiliation(s)
- Ce Li
- Key Laboratory of Marine Environmental Corrosion and Biofouling, Institute of Oceanology, Chinese Academy of Science, Qingdao 266071, China; Laoshan Laboratory, Qingdao 266237, China; Center for Ocean Mega-Science, Chinese Academic of Sciences, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jiajia Wu
- Key Laboratory of Marine Environmental Corrosion and Biofouling, Institute of Oceanology, Chinese Academy of Science, Qingdao 266071, China; Laoshan Laboratory, Qingdao 266237, China; Center for Ocean Mega-Science, Chinese Academic of Sciences, Qingdao 266071, China.
| | - Peng Wang
- Key Laboratory of Marine Environmental Corrosion and Biofouling, Institute of Oceanology, Chinese Academy of Science, Qingdao 266071, China; Laoshan Laboratory, Qingdao 266237, China; Center for Ocean Mega-Science, Chinese Academic of Sciences, Qingdao 266071, China.
| | - Dun Zhang
- Key Laboratory of Marine Environmental Corrosion and Biofouling, Institute of Oceanology, Chinese Academy of Science, Qingdao 266071, China; Laoshan Laboratory, Qingdao 266237, China; Center for Ocean Mega-Science, Chinese Academic of Sciences, Qingdao 266071, China.
| | - Liyang Zhu
- Key Laboratory of Marine Environmental Corrosion and Biofouling, Institute of Oceanology, Chinese Academy of Science, Qingdao 266071, China; Laoshan Laboratory, Qingdao 266237, China; Center for Ocean Mega-Science, Chinese Academic of Sciences, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yaohua Gao
- Key Laboratory of Marine Environmental Corrosion and Biofouling, Institute of Oceanology, Chinese Academy of Science, Qingdao 266071, China; Laoshan Laboratory, Qingdao 266237, China; Center for Ocean Mega-Science, Chinese Academic of Sciences, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wenkai Wang
- Key Laboratory of Marine Environmental Corrosion and Biofouling, Institute of Oceanology, Chinese Academy of Science, Qingdao 266071, China; Laoshan Laboratory, Qingdao 266237, China; Center for Ocean Mega-Science, Chinese Academic of Sciences, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hanzhe Sun
- Key Laboratory of Marine Environmental Corrosion and Biofouling, Institute of Oceanology, Chinese Academy of Science, Qingdao 266071, China; Laoshan Laboratory, Qingdao 266237, China; Center for Ocean Mega-Science, Chinese Academic of Sciences, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China
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3
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Huang J, Xu Z, Zhou T, Zhang LH, Xu Z. Suppression of Pseudomonas aeruginosa type III secretion system by a novel calcium-responsive signaling pathway. iScience 2024; 27:109690. [PMID: 38660402 PMCID: PMC11039405 DOI: 10.1016/j.isci.2024.109690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 01/31/2024] [Accepted: 04/05/2024] [Indexed: 04/26/2024] Open
Abstract
Expression of the type III secretion system (T3SS) in Pseudomonas aeruginosa is exquisitely controlled by diverse environmental or host-related signals such as calcium (Ca2+), however, the signal transduction pathways remain largely elusive. In this study, we reported that FleR, the response regulator of the two-component system FleS/FleR, inhibits T3SS gene expression and virulence of P. aeruginosa uncoupled from its cognate histidine kinase FleS. Interestingly, FleR was found to repress T3SS gene expression under Ca2+-rich conditions independently of its DNA-binding domain. FleR activates the elevation of intracellular c-di-GMP contents and FleQ serves as the c-di-GMP effector to repress T3SS gene expression through the Gac/Rsm pathway. Remarkably, we found that AmrZ, a member of the FleR regulon, inhibits T3SS gene expression by directly targeting the promoter of exsCEBA in an expression level-dependent manner. This study revealed an intricate regulatory network that connects P. aeruginosa T3SS gene expression to the Ca2+ signal.
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Affiliation(s)
- Jiahui Huang
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
| | - Zirui Xu
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
| | - Tian Zhou
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
| | - Lian-Hui Zhang
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
- Guangdong Laboratory for Lingnan Modern Agriculture, South China Agricultural University, Guangzhou, China
| | - Zeling Xu
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
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4
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Conaway A, Todorovic I, Mould DL, Hogan DA. Loss of LasR function leads to decreased repression of Pseudomonas aeruginosa PhoB activity at physiological phosphate concentrations. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.27.586856. [PMID: 38585852 PMCID: PMC10996656 DOI: 10.1101/2024.03.27.586856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
While the Pseudomonas aeruginosa LasR transcription factor plays a role in quorum sensing (QS) across phylogenetically-distinct lineages, isolates with loss-of-function mutations in lasR (LasR- strains) are commonly found in diverse settings including infections where they are associated with worse clinical outcomes. In LasR- strains, the transcription factor RhlR, which is controlled by LasR, can be alternately activated in low inorganic phosphate (Pi) concentrations via the two-component system PhoR-PhoB. Here, we demonstrate a new link between LasR and PhoB in which the absence of LasR increases PhoB activity at physiological Pi concentrations and raises the Pi concentration necessary for PhoB inhibition. PhoB activity was also less repressed by Pi in mutants lacking different QS regulators (RhlR and PqsR) and in mutants lacking genes required for the production of QS-regulated phenazines suggesting that decreased phenazine production was one reason for decreased PhoB repression by Pi in LasR- strains. In addition, the CbrA-CbrB two-component system, which is elevated in LasR- strains, was necessary for reduced PhoB repression by Pi and a Δcrc mutant, which lacks the CbrA-CbrB-controlled translational repressor, activated PhoB at higher Pi concentrations than the wild type. The ΔlasR mutant had a PhoB-dependent growth advantage in a medium with no added Pi and increased virulence-determinant gene expression in a medium with physiological Pi, in part through reactivation of QS. This work suggests PhoB activity may contribute to the virulence of LasR- P. aeruginosa and subsequent clinical outcomes.
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Affiliation(s)
- Amy Conaway
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, NH USA
| | - Igor Todorovic
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, NH USA
| | - Dallas L. Mould
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, NH USA
| | - Deborah A. Hogan
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, NH USA
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5
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Gentile R, Modric M, Thiele B, Jaeger KE, Kovacic F, Schott-Verdugo S, Gohlke H. Molecular Mechanisms Underlying Medium-Chain Free Fatty Acid-Regulated Activity of the Phospholipase PlaF from Pseudomonas aeruginosa. JACS AU 2024; 4:958-973. [PMID: 38559719 PMCID: PMC10976570 DOI: 10.1021/jacsau.3c00725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 01/08/2024] [Accepted: 01/09/2024] [Indexed: 04/04/2024]
Abstract
PlaF is a membrane-bound phospholipase A1 from Pseudomonas aeruginosa that is involved in remodeling membrane glycerophospholipids (GPLs) and modulating virulence-associated signaling and metabolic pathways. Previously, we identified the role of medium-chain free fatty acids (FFAs) in inhibiting PlaF activity and promoting homodimerization, yet the underlying molecular mechanism remained elusive. Here, we used unbiased and biased molecular dynamics simulations and free energy computations to assess how PlaF interacts with FFAs localized in the water milieu surrounding the bilayer or within the bilayer and how these interactions regulate PlaF activity. Medium-chain FFAs localized in the upper bilayer leaflet can stabilize inactive dimeric PlaF, likely through interactions with charged surface residues, as has been experimentally validated. Potential of mean force (PMF) computations indicate that membrane-bound FFAs may facilitate the activation of monomeric PlaF by lowering the activation barrier for changing into a tilted, active configuration. We estimated that the coupled equilibria of PlaF monomerization-dimerization and tilting at the physiological concentration of PlaF lead to the majority of PlaF forming inactive dimers when in a cell membrane loaded with decanoic acid (C10). This is in agreement with a suggested in vivo product feedback loop and gas chromatography-mass spectrometry profiling results, indicating that PlaF catalyzes the release of C10 from P. aeruginosa membranes. Additionally, we found that C10 in the water milieu can access the catalytic site of active monomeric PlaF, contributing to the competitive component of C10-mediated PlaF inhibition. Our study provides mechanistic insights into how medium-chain FFAs may regulate the activity of PlaF, a potential bacterial drug target.
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Affiliation(s)
- Rocco Gentile
- Institute
for Pharmaceutical and Medicinal Chemistry, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany
| | - Matea Modric
- Institute
of Molecular Enzyme Technology, Heinrich
Heine University Düsseldorf, Forschungszentrum Jülich
GmbH, 52425 Jülich, Germany
| | - Björn Thiele
- Institute
of Bio- and Geosciences (IBG-2: Plant Sciences and IBG-3: Agrosphere), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Karl-Erich Jaeger
- Institute
of Molecular Enzyme Technology, Heinrich
Heine University Düsseldorf, Forschungszentrum Jülich
GmbH, 52425 Jülich, Germany
- Institute
of Bio- and Geosciences (IBG-1: Biotechnology), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Filip Kovacic
- Institute
of Molecular Enzyme Technology, Heinrich
Heine University Düsseldorf, Forschungszentrum Jülich
GmbH, 52425 Jülich, Germany
| | - Stephan Schott-Verdugo
- Institute
of Bio- and Geosciences (IBG-4: Bioinformatics), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Holger Gohlke
- Institute
for Pharmaceutical and Medicinal Chemistry, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany
- Institute
of Bio- and Geosciences (IBG-4: Bioinformatics), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
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6
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Sahoo PK, Sheenu, Jain D. REC domain stabilizes the active heptamer of σ 54-dependent transcription factor, FleR from Pseudomonas aeruginosa. iScience 2023; 26:108397. [PMID: 38058307 PMCID: PMC10696123 DOI: 10.1016/j.isci.2023.108397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2023] [Revised: 09/12/2023] [Accepted: 11/02/2023] [Indexed: 12/08/2023] Open
Abstract
Motility in Pseudomonas aeruginosa is mediated through a single, polar flagellum, which is essential for virulence, colonization, and biofilm formation. FleSR, a two-component system (TCS), serves as a critical checkpoint in flagellar assembly. FleR is a σ54-dependent response regulator that undergoes phosphorylation via cognate sensor kinase FleS for the assembly of the functionally active form. The active form remodels the σ54-RNAP complex to initiate transcription. Small-angle X-ray scattering, crystallography, and negative staining electron microscopy reconstructions of FleR revealed that it exists predominantly as a dimer in the inactive form with low ATPase activity and assembles into heptamers upon phosphorylation with amplified ATPase activity. We establish that receiver (REC) domain stabilizes the heptamers and is indispensable for assembly of the functional phosphorylated form of FleR. The structural, biochemical, and in vivo complementation assays provide details of the phosphorylation-mediated assembly of FleR to regulate the expression of flagellar genes.
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Affiliation(s)
- Pankaj Kumar Sahoo
- Transcription Regulation Lab, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad 121001, India
| | - Sheenu
- Transcription Regulation Lab, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad 121001, India
| | - Deepti Jain
- Transcription Regulation Lab, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad 121001, India
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7
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Kolodkin-Gal I, Parsek MR, Patrauchan MA. The roles of calcium signaling and calcium deposition in microbial multicellularity. Trends Microbiol 2023; 31:1225-1237. [PMID: 37429751 PMCID: PMC10772221 DOI: 10.1016/j.tim.2023.06.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 06/07/2023] [Accepted: 06/12/2023] [Indexed: 07/12/2023]
Abstract
Calcium signaling is an essential mediator of signal-controlling gene expression in most developmental systems. In addition, calcium has established extracellular functions as a structural component of biogenic minerals found in complex tissues. In bacteria, the formation of calcium carbonate structures is associated with complex colony morphology. Genes promoting the formation of biogenic minerals are essential for proper biofilm development and protection against antimicrobial solutes and toxins. Here we review recent findings on the role of calcium and calcium signaling as emerging regulators of biofilm formation in beneficial bacteria, as well as essential mediators of biofilm formation and virulence in human pathogens. The presented analysis concludes that the new understanding of calcium signaling may help to improve the performance of beneficial strains for sustainable agriculture, microbiome manipulation, and sustainable construction. Unraveling the roles of calcium may also promote the development of novel therapies against biofilm infections that target calcium uptake, calcium sensors, and calcium carbonate deposition.
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Affiliation(s)
- Ilana Kolodkin-Gal
- Department of Plant Pathology and Microbiology, Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel.
| | - Matthew R Parsek
- Department of Microbiology, University of Washington, Seattle, WA, USA.
| | - Marianna A Patrauchan
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, USA.
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8
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Kaur M, Buyck JM, Goormaghtigh F, Decout JL, Mozaheb N, Mingeot-Leclercq MP. Deficient Pseudomonas aeruginosa in MlaA/VacJ outer membrane lipoprotein shows decrease in rhamnolipids secretion, motility, and biofilm formation, and increase in fluoroquinolones susceptibility and innate immune response. Res Microbiol 2023; 174:104132. [PMID: 37660742 DOI: 10.1016/j.resmic.2023.104132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 08/23/2023] [Accepted: 08/29/2023] [Indexed: 09/05/2023]
Abstract
Pseudomonas aeruginosa, a Gram-negative bacterium that causes severe hospital acquired infections poses threat by its ability for adaptation to various growth modes and environmental conditions and by its intrinsic resistance to antibiotics. The latter is mainly due to the outer membrane (OM) asymmetry which is maintained by the Mla pathway resulting in the retrograde transport of glycerophospholipids from the OM to the inner membrane. It comprises six Mla proteins, including MlaA, an OM lipoprotein involved in the removal of glycerophospholipids mislocalized at the outer leaflet of OM. To investigate the role of P. aeruginosa OM asymmetry especially MlaA, this study investigated the effect of mlaA deletion on (i) the susceptibility to antibiotics, (ii) the secretion of virulence factors, the motility, biofilm formation, and (iii) the inflammatory response. mlaA deletion in P. aeruginosa ATCC27853 results in phenotypic changes including, an increase in fluoroquinolones susceptibility and in PQS (Pseudomonas Quinolone Signal) and TNF-α release and a decrease in rhamnolipids secretion, motility and biofilm formation. Investigating how the mlaA knockout impacts on antibiotic susceptibility, bacterial virulence and innate immune response will help to elucidate the biological significance of the Mla system and contribute to the understanding of MlaA in P. aeruginosa OM asymmetry.
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Affiliation(s)
- M Kaur
- Université catholique de Louvain, Louvain Drug Research Institute, Pharmacologie Cellulaire et Moléculaire, Avenue E. Mounier 73, UCL B1.73.05, 1200 Brussels, Belgium.
| | - J M Buyck
- University of Poitiers, INSERM U1070, Poitiers, France.
| | - F Goormaghtigh
- Université catholique de Louvain, Louvain Drug Research Institute, Pharmacologie Cellulaire et Moléculaire, Avenue E. Mounier 73, UCL B1.73.05, 1200 Brussels, Belgium.
| | - J-L Decout
- Université Grenoble Alpes, CNRS, Département de Pharmacochimie Moléculaire, Rue de la Chimie, F-38041 Grenoble, France.
| | - N Mozaheb
- Université catholique de Louvain, Louvain Drug Research Institute, Pharmacologie Cellulaire et Moléculaire, Avenue E. Mounier 73, UCL B1.73.05, 1200 Brussels, Belgium.
| | - M-P Mingeot-Leclercq
- Université catholique de Louvain, Louvain Drug Research Institute, Pharmacologie Cellulaire et Moléculaire, Avenue E. Mounier 73, UCL B1.73.05, 1200 Brussels, Belgium.
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9
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Zhao NL, Zhu ZQ, Feng HZ, Song YJ, Huang Q, Mou XY, Nong C, He YX, Bao R. Host-derived peptide signals regulate Pseudomonas aeruginosa virulence stress via the ParRS and CprRS two-component systems. JOURNAL OF HAZARDOUS MATERIALS 2023; 460:132512. [PMID: 37703740 DOI: 10.1016/j.jhazmat.2023.132512] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 08/30/2023] [Accepted: 09/07/2023] [Indexed: 09/15/2023]
Abstract
Pseudomonas aeruginosa, a versatile bacterium, has dual significance because of its beneficial roles in environmental soil processes and its detrimental effects as a nosocomial pathogen that causes clinical infections. Understanding adaptability to environmental stress is essential. This investigation delves into the complex interplay of two-component system (TCS), specifically ParRS and CprRS, as P. aeruginosa interprets host signals and navigates stress challenges. In this study, through phenotypic and proteomic analyses, the nuanced contributions of ParRS and CprRS to the pathogenesis and resilience mechanisms were elucidated. Furthermore, the indispensable roles of the ParS and CprS extracellular sensor domains in orchestrating signal perception remain unknown. Structural revelations imply a remarkable convergence of TCS sensors in interacting with host peptides, suggesting evolutionary strategies for bacterial adaptation. This pioneering work not only established links between cationic antimicrobial peptide (CAMP) resistance-associated TCSs and virulence modulation in nosocomial bacteria, but also transcended conventional boundaries. These implications extend beyond clinical resistance, permeating into the realm of soil revitalization and environmental guardianship. As it unveils P. aeruginosa intricacies, this study assumes a mantle of guiding strategies to mitigate clinical hazards, harness environmental advantages, and propel sustainable solutions forward.
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Affiliation(s)
- Ning-Lin Zhao
- Center of Infectious Diseases, Division of Infectious Diseases in State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Zi-Qi Zhu
- Center of Infectious Diseases, Division of Infectious Diseases in State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Han-Zhong Feng
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Ying-Jie Song
- College of Life Science, Sichuan Normal University, Chengdu 610101, China
| | - Qin Huang
- Center of Infectious Diseases, Division of Infectious Diseases in State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Xing-Yu Mou
- Center of Infectious Diseases, Division of Infectious Diseases in State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Cheng Nong
- Center of Infectious Diseases, Division of Infectious Diseases in State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Yong-Xing He
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China.
| | - Rui Bao
- Center of Infectious Diseases, Division of Infectious Diseases in State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu 610041, China.
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10
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Sánchez-Jiménez A, Llamas MA, Marcos-Torres FJ. Transcriptional Regulators Controlling Virulence in Pseudomonas aeruginosa. Int J Mol Sci 2023; 24:11895. [PMID: 37569271 PMCID: PMC10418997 DOI: 10.3390/ijms241511895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 07/21/2023] [Accepted: 07/22/2023] [Indexed: 08/13/2023] Open
Abstract
Pseudomonas aeruginosa is a pathogen capable of colonizing virtually every human tissue. The host colonization competence and versatility of this pathogen are powered by a wide array of virulence factors necessary in different steps of the infection process. This includes factors involved in bacterial motility and attachment, biofilm formation, the production and secretion of extracellular invasive enzymes and exotoxins, the production of toxic secondary metabolites, and the acquisition of iron. Expression of these virulence factors during infection is tightly regulated, which allows their production only when they are needed. This process optimizes host colonization and virulence. In this work, we review the intricate network of transcriptional regulators that control the expression of virulence factors in P. aeruginosa, including one- and two-component systems and σ factors. Because inhibition of virulence holds promise as a target for new antimicrobials, blocking the regulators that trigger the production of virulence determinants in P. aeruginosa is a promising strategy to fight this clinically relevant pathogen.
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Affiliation(s)
| | - María A. Llamas
- Department of Biotechnology and Environmental Protection, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas, 18008 Granada, Spain;
| | - Francisco Javier Marcos-Torres
- Department of Biotechnology and Environmental Protection, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas, 18008 Granada, Spain;
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11
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Harris KB, Flynn KM, Cooper VS. Polygenic Adaptation and Clonal Interference Enable Sustained Diversity in Experimental Pseudomonas aeruginosa Populations. Mol Biol Evol 2021; 38:5359-5375. [PMID: 34410431 PMCID: PMC8662654 DOI: 10.1093/molbev/msab248] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
How biodiversity arises and can be maintained in asexual microbial populations growing on a single resource remains unclear. Many models presume that beneficial genotypes will outgrow others and purge variation via selective sweeps. Environmental structure like that found in biofilms, which are associated with persistence during infection and other stressful conditions, may oppose this process and preserve variation. We tested this hypothesis by evolving Pseudomonas aeruginosa populations in biofilm-promoting arginine media for 3 months, using both a bead model of the biofilm life cycle and planktonic serial transfer. Surprisingly, adaptation and diversification were mostly uninterrupted by fixation events that eliminate diversity, with hundreds of mutations maintained at intermediate frequencies. The exceptions included genotypes with mutator alleles that also accelerated genetic diversification. Despite the rarity of hard sweeps, a remarkable 40 genes acquired parallel mutations in both treatments and often among competing genotypes within a population. These incomplete soft sweeps include several transporters (including pitA, pntB, nosD, and pchF) suggesting adaptation to the growth media that becomes highly alkaline during growth. Further, genes involved in signal transduction (including gacS, aer2, bdlA, and PA14_71750) reflect likely adaptations to biofilm-inducing conditions. Contrary to evolution experiments that select mutations in a few genes, these results suggest that some environments may expose a larger fraction of the genome and select for many adaptations at once. Thus, even growth on a sole carbon source can lead to persistent genetic and phenotypic variation despite strong selection that would normally purge diversity.
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Affiliation(s)
- Katrina B Harris
- Department of Microbiology and Molecular Genetics, and Center for Evolutionary Biology and Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Kenneth M Flynn
- Department of Molecular, Cellular, and Biomedical Sciences, University of New Hampshire, Durham, NH, USA
| | - Vaughn S Cooper
- Department of Microbiology and Molecular Genetics, and Center for Evolutionary Biology and Medicine, University of Pittsburgh, Pittsburgh, PA, USA
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12
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Trouillon J, Imbert L, Villard AM, Vernet T, Attrée I, Elsen S. Determination of the two-component systems regulatory network reveals core and accessory regulations across Pseudomonas aeruginosa lineages. Nucleic Acids Res 2021; 49:11476-11490. [PMID: 34718721 PMCID: PMC8599809 DOI: 10.1093/nar/gkab928] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 08/24/2021] [Accepted: 09/28/2021] [Indexed: 01/01/2023] Open
Abstract
Pseudomonas aeruginosa possesses one of the most complex bacterial regulatory networks, which largely contributes to its success as a pathogen. However, most of its transcription factors (TFs) are still uncharacterized and the potential intra-species variability in regulatory networks has been mostly ignored so far. Here, we used DAP-seq to map the genome-wide binding sites of all 55 DNA-binding two-component systems (TCSs) response regulators (RRs) across the three major P. aeruginosa lineages. The resulting networks encompass about 40% of all genes in each strain and contain numerous new regulatory interactions across most major physiological processes. Strikingly, about half of the detected targets are specific to only one or two strains, revealing a previously unknown large functional diversity of TFs within a single species. Three main mechanisms were found to drive this diversity, including differences in accessory genome content, as exemplified by the strain-specific plasmid in IHMA87 outlier strain which harbors numerous binding sites of conserved chromosomally-encoded RRs. Additionally, most RRs display potential auto-regulation or RR-RR cross-regulation, bringing to light the vast complexity of this network. Overall, we provide the first complete delineation of the TCSs regulatory network in P. aeruginosa that will represent an important resource for future studies on this pathogen.
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Affiliation(s)
- Julian Trouillon
- Université Grenoble Alpes, CNRS, CEA, IBS UMR 5075, Team Bacterial Pathogenesis and Cellular Responses, 38044 Grenoble, France
| | - Lionel Imbert
- Université Grenoble Alpes, CNRS, CEA, IBS UMR 5075, 38044 Grenoble, France
- Université Grenoble Alpes, CNRS, CEA, EMBL, ISBG UAR 3518, 38044 Grenoble, France
| | - Anne-Marie Villard
- Université Grenoble Alpes, CNRS, CEA, IBS UMR 5075, 38044 Grenoble, France
| | - Thierry Vernet
- Université Grenoble Alpes, CNRS, CEA, IBS UMR 5075, 38044 Grenoble, France
| | - Ina Attrée
- Université Grenoble Alpes, CNRS, CEA, IBS UMR 5075, Team Bacterial Pathogenesis and Cellular Responses, 38044 Grenoble, France
| | - Sylvie Elsen
- Université Grenoble Alpes, CNRS, CEA, IBS UMR 5075, Team Bacterial Pathogenesis and Cellular Responses, 38044 Grenoble, France
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13
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Sultan M, Arya R, Kim KK. Roles of Two-Component Systems in Pseudomonas aeruginosa Virulence. Int J Mol Sci 2021; 22:12152. [PMID: 34830033 PMCID: PMC8623646 DOI: 10.3390/ijms222212152] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 11/01/2021] [Accepted: 11/02/2021] [Indexed: 12/28/2022] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen that synthesizes and secretes a wide range of virulence factors. P. aeruginosa poses a potential threat to human health worldwide due to its omnipresent nature, robust host accumulation, high virulence, and significant resistance to multiple antibiotics. The pathogenicity of P. aeruginosa, which is associated with acute and chronic infections, is linked with multiple virulence factors and associated secretion systems, such as the ability to form and utilize a biofilm, pili, flagella, alginate, pyocyanin, proteases, and toxins. Two-component systems (TCSs) of P. aeruginosa perform an essential role in controlling virulence factors in response to internal and external stimuli. Therefore, understanding the mechanism of TCSs to perceive and respond to signals from the environment and control the production of virulence factors during infection is essential to understanding the diseases caused by P. aeruginosa infection and further develop new antibiotics to treat this pathogen. This review discusses the important virulence factors of P. aeruginosa and the understanding of their regulation through TCSs by focusing on biofilm, motility, pyocyanin, and cytotoxins.
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Affiliation(s)
| | - Rekha Arya
- Department of Precision Medicine, Graduate School of Basic Medical Science (GSBMS), Institute for Antimicrobial Resistance Research and Therapeutics, Sungkyunkwan University School of Medicine, Suwon 16419, Korea;
| | - Kyeong Kyu Kim
- Department of Precision Medicine, Graduate School of Basic Medical Science (GSBMS), Institute for Antimicrobial Resistance Research and Therapeutics, Sungkyunkwan University School of Medicine, Suwon 16419, Korea;
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14
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Two-Component Signaling Systems Regulate Diverse Virulence-Associated Traits in Pseudomonas aeruginosa. Appl Environ Microbiol 2021; 87:AEM.03089-20. [PMID: 33771779 DOI: 10.1128/aem.03089-20] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 03/18/2021] [Indexed: 12/30/2022] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen that can cause problematic infections at different sites throughout the human body. P. aeruginosa encodes a large suite of over 60 two-component signaling systems that enable cells to rapidly sense and respond to external signals. Previous work has shown that some of these sensory systems contribute to P. aeruginosa pathogenesis, but the virulence-associated processes and phenotypic traits that each of these systems controls are still largely unclear. To aid investigations of these sensory systems, we have generated deletion strains for each of 64 genes encoding histidine kinases and one histidine phosphotransferase in P. aeruginosa PA14. We carried out initial phenotypic characterizations of this collection by assaying these mutants for over a dozen virulence-associated traits, and we found that each of these phenotypes is regulated by multiple sensory systems. Our work highlights the usefulness of this collection for further studies of P. aeruginosa two-component signaling systems and provides insight into how these systems may contribute to P. aeruginosa infection.IMPORTANCE Pseudomonas aeruginosa can grow and survive under a wide range of conditions, including as a human pathogen. As such, P. aeruginosa must be able to sense and respond to diverse signals and cues in its environment. This sensory capability is endowed in part by the hundreds of two-component signaling proteins encoded in the P. aeruginosa genome, but the precise roles of each remain poorly defined. To facilitate systematic study of the signaling repertoire of P. aeruginosa PA14, we generated a library of deletion strains, each lacking one of the 64 histidine kinases. By subjecting these strains to a battery of phenotypic assays, we confirmed the functions of many and unveiled roles for dozens of previously uncharacterized histidine kinases in controlling various traits, many of which are associated with P. aeruginosa virulence. Thus, this work provides new insight into the functions of two-component signaling proteins and provides a resource for future investigations.
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15
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Eng T, Banerjee D, Lau AK, Bowden E, Herbert RA, Trinh J, Prahl JP, Deutschbauer A, Tanjore D, Mukhopadhyay A. Engineering Pseudomonas putida for efficient aromatic conversion to bioproduct using high throughput screening in a bioreactor. Metab Eng 2021; 66:229-238. [PMID: 33964456 DOI: 10.1016/j.ymben.2021.04.015] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Revised: 04/30/2021] [Accepted: 04/30/2021] [Indexed: 12/18/2022]
Abstract
Pseudomonas putida KT2440 is an emerging biomanufacturing host amenable for use with renewable carbon streams including aromatics such as para-coumarate. We used a pooled transposon library disrupting nearly all (4,778) non-essential genes to characterize this microbe under common stirred-tank bioreactor parameters with quantitative fitness assays. Assessing differential fitness values by monitoring changes in mutant strain abundance identified 33 gene mutants with improved fitness across multiple stirred-tank bioreactor formats. Twenty-one deletion strains from this subset were reconstructed, including GacA, a regulator, TtgB, an ABC transporter, and PP_0063, a lipid A acyltransferase. Thirteen deletion strains with roles in varying cellular functions were evaluated for conversion of para-coumarate, to a heterologous bioproduct, indigoidine. Several mutants, such as the ΔgacA strain improved fitness in a bioreactor by 35 fold and showed an 8-fold improvement in indigoidine production (4.5 g/L, 0.29 g/g, 23% of maximum theoretical yield) from para-coumarate as the carbon source.
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Affiliation(s)
- Thomas Eng
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, 5885, Hollis Street, Emeryville, CA, USA; Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Rd, Berkeley, CA, USA
| | - Deepanwita Banerjee
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, 5885, Hollis Street, Emeryville, CA, USA; Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Rd, Berkeley, CA, USA
| | - Andrew K Lau
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, 5885, Hollis Street, Emeryville, CA, USA; Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Rd, Berkeley, CA, USA
| | - Emily Bowden
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, 5885, Hollis Street, Emeryville, CA, USA; Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Rd, Berkeley, CA, USA
| | - Robin A Herbert
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, 5885, Hollis Street, Emeryville, CA, USA; Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Rd, Berkeley, CA, USA
| | - Jessica Trinh
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, 5885, Hollis Street, Emeryville, CA, USA; Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Rd, Berkeley, CA, USA
| | - Jan-Philip Prahl
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Rd, Berkeley, CA, USA; Advanced Biofuels and Bioproducts Process Development Unit, Lawrence Berkeley National Laboratory, Hollis Street, Emeryville, CA, 5885, USA
| | - Adam Deutschbauer
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Rd, Berkeley, CA, USA
| | - Deepti Tanjore
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Rd, Berkeley, CA, USA; Advanced Biofuels and Bioproducts Process Development Unit, Lawrence Berkeley National Laboratory, Hollis Street, Emeryville, CA, 5885, USA
| | - Aindrila Mukhopadhyay
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, 5885, Hollis Street, Emeryville, CA, USA; Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Rd, Berkeley, CA, USA; Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Rd, Berkeley, CA, USA.
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16
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Pseudomonas aeruginosa as a Model To Study Chemosensory Pathway Signaling. Microbiol Mol Biol Rev 2021; 85:85/1/e00151-20. [PMID: 33441490 DOI: 10.1128/mmbr.00151-20] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Bacteria have evolved a variety of signal transduction mechanisms that generate different outputs in response to external stimuli. Chemosensory pathways are widespread in bacteria and are among the most complex signaling mechanisms, requiring the participation of at least six proteins. These pathways mediate flagellar chemotaxis, in addition to controlling alternative functions such as second messenger levels or twitching motility. The human pathogen Pseudomonas aeruginosa has four different chemosensory pathways that carry out different functions and are stimulated by signal binding to 26 chemoreceptors. Recent research employing a diverse range of experimental approaches has advanced enormously our knowledge on these four pathways, establishing P. aeruginosa as a primary model organism in this field. In the first part of this article, we review data on the function and physiological relevance of chemosensory pathways as well as their involvement in virulence, whereas the different transcriptional and posttranscriptional regulatory mechanisms that govern pathway function are summarized in the second part. The information presented will be of help to advance the understanding of pathway function in other organisms.
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17
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Badal D, Jayarani AV, Kollaran MA, Kumar A, Singh V. Pseudomonas aeruginosa biofilm formation on endotracheal tubes requires multiple two-component systems. J Med Microbiol 2020; 69:906-919. [PMID: 32459613 DOI: 10.1099/jmm.0.001199] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Introduction. Indwelling medical devices such as endotracheal tubes (ETTs), urinary catheters, vascular access devices, tracheostomies and feeding tubes are often associated with hospital-acquired infections. Bacterial biofilm formed on the ETTs in intubated patients is a significant risk factor associated with ventilator-associated pneumonia. Pseudomonas aeruginosa is one of the four frequently encountered bacteria responsible for causing pneumonia, and the biofilm formation on ETTs. However, understanding of biofilm formation on ETT and interventions to prevent biofilm remains lagging. The ability to sense and adapt to external cues contributes to their success. Thus, the biofilm formation is likely to be influenced by the two-component systems (TCSs) that are composed of a membrane-associated sensor kinase and an intracellular response regulator.Aim. This study aims to establish an in vitro method to analyse the P. aeruginosa biofilm formation on ETTs, and identify the TCSs that contribute to this process.Methodology. In total, 112 P. aeruginosa PA14 TCS mutants were tested for their ability to form biofilm on ETTs, their effect on quorum sensing (QS) and motility.Results. Out of 112 TCS mutants studied, 56 had altered biofilm biomass on ETTs. Although the biofilm formation on ETTs is QS-dependent, none of the 56 loci controlled quorum signal. Of these, 18 novel TCSs specific to ETT biofilm were identified, namely, AauS, AgtS, ColR, CopS, CprR, NasT, KdpD, ParS, PmrB, PprA, PvrS, RcsC, PA14_11120, PA14_32580, PA14_45880, PA14_49420, PA14_52240, PA14_70790. The set of 56 included the GacS network, TCS proteins involved in fimbriae synthesis, TCS proteins involved in antimicrobial peptide resistance, and surface-sensing. Additionally, several of the TCS-encoding genes involved in biofilm formation on ETTs were found to be linked to flagellum-dependent swimming motility.Conclusions. Our study established an in vitro method for studying P. aeruginosa biofilm formation on the ETT surfaces. We also identified novel ETT-specific TCSs that could serve as targets to prevent biofilm formation on indwelling devices frequently used in clinical settings.
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Affiliation(s)
- Divakar Badal
- Department of Biosystems Sciences and Engineering, Indian Institute of Science, Bangalore, Karnataka, INDIA
| | - Abhijith Vimal Jayarani
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore, Karnataka, INDIA
| | - Mohammed Ameen Kollaran
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore, Karnataka, INDIA
| | - Aloke Kumar
- Department of Mechanical Engineering, Indian Institute of Science, Bangalore, Karnataka, INDIA.,Department of Biosystems Sciences and Engineering, Indian Institute of Science, Bangalore, Karnataka, INDIA
| | - Varsha Singh
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore, Karnataka, INDIA.,Department of Biosystems Sciences and Engineering, Indian Institute of Science, Bangalore, Karnataka, INDIA
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18
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Alford MA, Baghela A, Yeung ATY, Pletzer D, Hancock REW. NtrBC Regulates Invasiveness and Virulence of Pseudomonas aeruginosa During High-Density Infection. Front Microbiol 2020; 11:773. [PMID: 32431676 PMCID: PMC7214821 DOI: 10.3389/fmicb.2020.00773] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Accepted: 03/31/2020] [Indexed: 12/21/2022] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen that is a major cause of nosocomial and chronic infections contributing to morbidity and mortality in cystic fibrosis patients. One of the reasons for its success as a pathogen is its ability to adapt to a broad range of circumstances. Here, we show the involvement of the general nitrogen regulator NtrBC, which is structurally conserved but functionally diverse across species, in pathogenic and adaptive states of P. aeruginosa. The role of NtrB and NtrC was examined in progressive or chronic infections, which revealed that mutants (ΔntrB, ΔntrC, and ΔntrBC) were reduced in their ability to invade and cause damage in a high-density abscess model in vivo. Progressive infections were established with mutants in the highly virulent PA14 genetic background, whereas chronic infections were established with mutants in the less virulent clinical isolate LESB58 genetic background. Characterization of adaptive lifestyles in vitro confirmed that the double ΔntrBC mutant demonstrated >40% inhibition of biofilm formation, a nearly complete inhibition of swarming motility, and a modest decrease and altered surfing motility colony appearance; with the exception of swarming, single mutants generally had more subtle or no changes. Transcriptional profiles of deletion mutants under swarming conditions were defined using RNA-Seq and unveiled dysregulated expression of hundreds of genes implicated in virulence in PA14 and LESB58 chronic lung infections, as well as carbon and nitrogen metabolism. Thus, transcriptional profiles were validated by testing responsiveness of mutants to several key intermediates of central metabolic pathways. These results indicate that NtrBC is a global regulatory system involved in both pathological and physiological processes relevant to the success of Pseudomonas in high-density infection.
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Affiliation(s)
- Morgan A Alford
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada
| | - Arjun Baghela
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada
| | | | - Daniel Pletzer
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada.,Department of Microbiology, University of Otago, Dunedin, New Zealand
| | - Robert E W Hancock
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada.,Wellcome Sanger Institute, Hinxton, United Kingdom
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19
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Kollaran AM, Joge S, Kotian HS, Badal D, Prakash D, Mishra A, Varma M, Singh V. Context-Specific Requirement of Forty-Four Two-Component Loci in Pseudomonas aeruginosa Swarming. iScience 2019; 13:305-317. [PMID: 30877999 PMCID: PMC6423354 DOI: 10.1016/j.isci.2019.02.028] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Revised: 12/18/2018] [Accepted: 02/26/2019] [Indexed: 11/30/2022] Open
Abstract
Swarming in Pseudomonas aeruginosa is a coordinated movement of bacteria over semisolid surfaces (0.5%-0.7% agar). On soft agar, P. aeruginosa exhibits a dendritic swarm pattern, with multiple levels of branching. However, the swarm patterns typically vary depending upon the experimental design. In the present study, we show that the pattern characteristics of P. aeruginosa swarm are highly environment dependent. We define several quantifiable, macroscale features of the swarm to study the plasticity of the swarm, observed across different nutrient formulations. Furthermore, through a targeted screen of 113 two-component system (TCS) loci of the P. aeruginosa strain PA14, we show that forty-four TCS genes regulate swarming in PA14 in a contextual fashion. However, only four TCS genes-fleR, fleS, gacS, and PA14_59770-were found essential for swarming. Notably, many swarming-defective TCS mutants were found highly efficient in biofilm formation, indicating opposing roles for many TCS loci.
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Affiliation(s)
- Ameen M Kollaran
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Shubham Joge
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Harshitha S Kotian
- Centre for Nano Science and Engineering, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Divakar Badal
- Biosystems Science and Engineering, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Deep Prakash
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Ayushi Mishra
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Manoj Varma
- Centre for Nano Science and Engineering, Indian Institute of Science, Bangalore, Karnataka 560012, India; Robert Bosch Centre for Cyber Physical Systems, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Varsha Singh
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore, Karnataka 560012, India; Biosystems Science and Engineering, Indian Institute of Science, Bangalore, Karnataka 560012, India.
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