1
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Weimann A, Dinan AM, Ruis C, Bernut A, Pont S, Brown K, Ryan J, Santos L, Ellison L, Ukor E, Pandurangan AP, Krokowski S, Blundell TL, Welch M, Blane B, Judge K, Bousfield R, Brown N, Bryant JM, Kukavica-Ibrulj I, Rampioni G, Leoni L, Harrison PT, Peacock SJ, Thomson NR, Gauthier J, Fothergill JL, Levesque RC, Parkhill J, Floto RA. Evolution and host-specific adaptation of Pseudomonas aeruginosa. Science 2024; 385:eadi0908. [PMID: 38963857 DOI: 10.1126/science.adi0908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Accepted: 05/02/2024] [Indexed: 07/06/2024]
Abstract
The major human bacterial pathogen Pseudomonas aeruginosa causes multidrug-resistant infections in people with underlying immunodeficiencies or structural lung diseases such as cystic fibrosis (CF). We show that a few environmental isolates, driven by horizontal gene acquisition, have become dominant epidemic clones that have sequentially emerged and spread through global transmission networks over the past 200 years. These clones demonstrate varying intrinsic propensities for infecting CF or non-CF individuals (linked to specific transcriptional changes enabling survival within macrophages); have undergone multiple rounds of convergent, host-specific adaptation; and have eventually lost their ability to transmit between different patient groups. Our findings thus explain the pathogenic evolution of P. aeruginosa and highlight the importance of global surveillance and cross-infection prevention in averting the emergence of future epidemic clones.
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Affiliation(s)
- Aaron Weimann
- Victor Phillip Dahdaleh Heart & Lung Research Institute, University of Cambridge, Cambridge, UK
- University of Cambridge Molecular Immunity Unit, MRC Laboratory of Molecular Biology, Cambridge, UK
- Cambridge Centre for AI in Medicine, University of Cambridge, Cambridge, UK
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
| | - Adam M Dinan
- Victor Phillip Dahdaleh Heart & Lung Research Institute, University of Cambridge, Cambridge, UK
- University of Cambridge Molecular Immunity Unit, MRC Laboratory of Molecular Biology, Cambridge, UK
- Cambridge Centre for AI in Medicine, University of Cambridge, Cambridge, UK
| | - Christopher Ruis
- Victor Phillip Dahdaleh Heart & Lung Research Institute, University of Cambridge, Cambridge, UK
- University of Cambridge Molecular Immunity Unit, MRC Laboratory of Molecular Biology, Cambridge, UK
- Cambridge Centre for AI in Medicine, University of Cambridge, Cambridge, UK
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
| | - Audrey Bernut
- Laboratory of Pathogens and Host Immunity (LPHI), UMR5235, CNRS/Université de Montpellier, Montpellier, France
| | - Stéphane Pont
- Laboratory of Pathogens and Host Immunity (LPHI), UMR5235, CNRS/Université de Montpellier, Montpellier, France
| | - Karen Brown
- Victor Phillip Dahdaleh Heart & Lung Research Institute, University of Cambridge, Cambridge, UK
- University of Cambridge Molecular Immunity Unit, MRC Laboratory of Molecular Biology, Cambridge, UK
- Cambridge Centre for Lung Infection, Royal Papworth Hospital, Cambridge, UK
| | - Judy Ryan
- Victor Phillip Dahdaleh Heart & Lung Research Institute, University of Cambridge, Cambridge, UK
- University of Cambridge Molecular Immunity Unit, MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Lúcia Santos
- Department of Physiology, Bioscience Institute, University College Cork, Cork, Ireland
| | - Louise Ellison
- University of Cambridge Molecular Immunity Unit, MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Emem Ukor
- University of Cambridge Molecular Immunity Unit, MRC Laboratory of Molecular Biology, Cambridge, UK
- Cambridge Centre for Lung Infection, Royal Papworth Hospital, Cambridge, UK
| | - Arun P Pandurangan
- Victor Phillip Dahdaleh Heart & Lung Research Institute, University of Cambridge, Cambridge, UK
- Department of Biochemistry, University of Cambridge, Cambridge, UK
- Department of Medicine, University of Cambridge, Cambridge, UK
| | - Sina Krokowski
- Victor Phillip Dahdaleh Heart & Lung Research Institute, University of Cambridge, Cambridge, UK
- University of Cambridge Molecular Immunity Unit, MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Tom L Blundell
- Victor Phillip Dahdaleh Heart & Lung Research Institute, University of Cambridge, Cambridge, UK
- Department of Biochemistry, University of Cambridge, Cambridge, UK
- Department of Medicine, University of Cambridge, Cambridge, UK
| | - Martin Welch
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Beth Blane
- Department of Medicine, University of Cambridge, Cambridge, UK
| | - Kim Judge
- Wellcome Sanger Institute, Hinxton, UK
| | - Rachel Bousfield
- Department of Medicine, University of Cambridge, Cambridge, UK
- Cambridge University Hospitals Trust, Cambridge, UK
| | | | | | - Irena Kukavica-Ibrulj
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec City, Québec, Canada
| | - Giordano Rampioni
- Department of Science, University Roma Tre, Rome, Italy
- IRCCS Fondazione Santa Lucia, Rome, Italy
| | - Livia Leoni
- Department of Science, University Roma Tre, Rome, Italy
| | - Patrick T Harrison
- Department of Physiology, Bioscience Institute, University College Cork, Cork, Ireland
| | - Sharon J Peacock
- Department of Medicine, University of Cambridge, Cambridge, UK
- Cambridge University Hospitals Trust, Cambridge, UK
| | - Nicholas R Thomson
- Wellcome Sanger Institute, Hinxton, UK
- London School of Hygiene and Tropical Medicine, London, UK
| | - Jeff Gauthier
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec City, Québec, Canada
| | - Jo L Fothergill
- Department of Clinical Infection, Microbiology and Immunology, University of Liverpool, Liverpool, UK
| | - Roger C Levesque
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec City, Québec, Canada
| | - Julian Parkhill
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
| | - R Andres Floto
- Victor Phillip Dahdaleh Heart & Lung Research Institute, University of Cambridge, Cambridge, UK
- University of Cambridge Molecular Immunity Unit, MRC Laboratory of Molecular Biology, Cambridge, UK
- Cambridge Centre for AI in Medicine, University of Cambridge, Cambridge, UK
- Cambridge Centre for Lung Infection, Royal Papworth Hospital, Cambridge, UK
- Department of Medicine, University of Cambridge, Cambridge, UK
- Cambridge University Hospitals Trust, Cambridge, UK
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2
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Xiao Y, Xiang W, Ma X, Gao D, Bayram H, Lorimer GH, Ghiladi RA, Xie Z, Wang J. HemN2 Regulates the Virulence of Pseudomonas donghuensis HYS through 7-Hydroxytropolone Synthesis and Oxidative Stress. BIOLOGY 2024; 13:373. [PMID: 38927253 PMCID: PMC11200716 DOI: 10.3390/biology13060373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2024] [Revised: 05/21/2024] [Accepted: 05/21/2024] [Indexed: 06/28/2024]
Abstract
Compared to pathogens Pseudomonas aeruginosa and P. putida, P. donghuensis HYS has stronger virulence towards Caenorhabditis elegans. However, the underlying mechanisms haven't been fully understood. The heme synthesis system is essential for Pseudomonas virulence, and former studies of HemN have focused on the synthesis of heme, while the relationship between HemN and Pseudomonas virulence were barely pursued. In this study, we hypothesized that hemN2 deficiency affected 7-hydroxytropolone (7-HT) biosynthesis and redox levels, thereby reducing bacterial virulence. There are four hemN genes in P. donghuensis HYS, and we reported for the first time that deletion of hemN2 significantly reduced the virulence of HYS towards C. elegans, whereas the reduction in virulence by the other three genes was not significant. Interestingly, hemN2 deletion significantly reduced colonization of P. donghuensis HYS in the gut of C. elegans. Further studies showed that HemN2 was regulated by GacS and participated in the virulence of P. donghuensis HYS towards C. elegans by mediating the synthesis of the virulence factor 7-HT. In addition, HemN2 and GacS regulated the virulence of P. donghuensis HYS by affecting antioxidant capacity and nitrative stress. In short, the findings that HemN2 was regulated by the Gac system and that it was involved in bacterial virulence via regulating 7-HT synthesis and redox levels were reported for the first time. These insights may enlighten further understanding of HemN-based virulence in the genus Pseudomonas.
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Affiliation(s)
- Yaqian Xiao
- Cooperative Innovation Center of Industrial Fermentation, Ministry of Education & Hubei Province, Hubei University of Technology, Wuhan 430068, China; (Y.X.); (W.X.); (X.M.)
- International Center for Redox Biology & Precision Medicine of Hubei Province, Hubei University of Technology, Wuhan 430068, China
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan 430072, China;
| | - Wang Xiang
- Cooperative Innovation Center of Industrial Fermentation, Ministry of Education & Hubei Province, Hubei University of Technology, Wuhan 430068, China; (Y.X.); (W.X.); (X.M.)
- International Center for Redox Biology & Precision Medicine of Hubei Province, Hubei University of Technology, Wuhan 430068, China
| | - Xuerui Ma
- Cooperative Innovation Center of Industrial Fermentation, Ministry of Education & Hubei Province, Hubei University of Technology, Wuhan 430068, China; (Y.X.); (W.X.); (X.M.)
- International Center for Redox Biology & Precision Medicine of Hubei Province, Hubei University of Technology, Wuhan 430068, China
| | - Donghao Gao
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan 430072, China;
| | - Hasan Bayram
- Department of Pulmonary Medicine, School of Medicine, Koc University, 34010 Istanbul, Turkey;
| | - George H. Lorimer
- Department of Chemistry, University of Maryland, College Park, MD 20742, USA;
| | - Reza A. Ghiladi
- Department of Chemistry, North Carolina State University, Raleigh, NC 27695, USA;
| | - Zhixiong Xie
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan 430072, China;
| | - Jun Wang
- Cooperative Innovation Center of Industrial Fermentation, Ministry of Education & Hubei Province, Hubei University of Technology, Wuhan 430068, China; (Y.X.); (W.X.); (X.M.)
- International Center for Redox Biology & Precision Medicine of Hubei Province, Hubei University of Technology, Wuhan 430068, China
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3
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Chowdhury-Paul S, Martínez-Ortíz IC, Pando-Robles V, Moreno S, Espín G, Merino E, Núñez C. The Azotobacter vinelandii AlgU regulon during vegetative growth and encysting conditions: A proteomic approach. PLoS One 2023; 18:e0286440. [PMID: 37967103 PMCID: PMC10651043 DOI: 10.1371/journal.pone.0286440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 10/24/2023] [Indexed: 11/17/2023] Open
Abstract
In the Pseduomonadacea family, the extracytoplasmic function sigma factor AlgU is crucial to withstand adverse conditions. Azotobacter vinelandii, a closed relative of Pseudomonas aeruginosa, has been a model for cellular differentiation in Gram-negative bacteria since it forms desiccation-resistant cysts. Previous work demonstrated the essential role of AlgU to withstand oxidative stress and on A. vinelandii differentiation, particularly for the positive control of alginate production. In this study, the AlgU regulon was dissected by a proteomic approach under vegetative growing conditions and upon encystment induction. Our results revealed several molecular targets that explained the requirement of this sigma factor during oxidative stress and extended its role in alginate production. Furthermore, we demonstrate that AlgU was necessary to produce alkyl resorcinols, a type of aromatic lipids that conform the cell membrane of the differentiated cell. AlgU was also found to positively regulate stress resistance proteins such as OsmC, LEA-1, or proteins involved in trehalose synthesis. A position-specific scoring-matrix (PSSM) was generated based on the consensus sequence recognized by AlgU in P. aeruginosa, which allowed the identification of direct AlgU targets in the A. vinelandii genome. This work further expands our knowledge about the function of the ECF sigma factor AlgU in A. vinelandii and contributes to explains its key regulatory role under adverse conditions.
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Affiliation(s)
- Sangita Chowdhury-Paul
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Morelos, México
| | - Iliana C. Martínez-Ortíz
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Morelos, México
| | - Victoria Pando-Robles
- Instituto Nacional de Salud Pública, Centro de Investigación Sobre Enfermedades Infecciosas, Cuernavaca, Morelos, México
| | - Soledad Moreno
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Morelos, México
| | - Guadalupe Espín
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Morelos, México
| | - Enrique Merino
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Morelos, México
| | - Cinthia Núñez
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Morelos, México
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4
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Salvà-Serra F, Jaén-Luchoro D, Marathe NP, Adlerberth I, Moore ERB, Karlsson R. Responses of carbapenemase-producing and non-producing carbapenem-resistant Pseudomonas aeruginosa strains to meropenem revealed by quantitative tandem mass spectrometry proteomics. Front Microbiol 2023; 13:1089140. [PMID: 36845973 PMCID: PMC9948630 DOI: 10.3389/fmicb.2022.1089140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Accepted: 12/08/2022] [Indexed: 02/11/2023] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen with increasing incidence of multidrug-resistant strains, including resistance to last-resort antibiotics, such as carbapenems. Resistances are often due to complex interplays of natural and acquired resistance mechanisms that are enhanced by its large regulatory network. This study describes the proteomic responses of two carbapenem-resistant P. aeruginosa strains of high-risk clones ST235 and ST395 to subminimal inhibitory concentrations (sub-MICs) of meropenem by identifying differentially regulated proteins and pathways. Strain CCUG 51971 carries a VIM-4 metallo-β-lactamase or 'classical' carbapenemase; strain CCUG 70744 carries no known acquired carbapenem-resistance genes and exhibits 'non-classical' carbapenem-resistance. Strains were cultivated with different sub-MICs of meropenem and analyzed, using quantitative shotgun proteomics based on tandem mass tag (TMT) isobaric labeling, nano-liquid chromatography tandem-mass spectrometry and complete genome sequences. Exposure of strains to sub-MICs of meropenem resulted in hundreds of differentially regulated proteins, including β-lactamases, proteins associated with transport, peptidoglycan metabolism, cell wall organization, and regulatory proteins. Strain CCUG 51971 showed upregulation of intrinsic β-lactamases and VIM-4 carbapenemase, while CCUG 70744 exhibited a combination of upregulated intrinsic β-lactamases, efflux pumps, penicillin-binding proteins and downregulation of porins. All components of the H1 type VI secretion system were upregulated in strain CCUG 51971. Multiple metabolic pathways were affected in both strains. Sub-MICs of meropenem cause marked changes in the proteomes of carbapenem-resistant strains of P. aeruginosa exhibiting different resistance mechanisms, involving a wide range of proteins, many uncharacterized, which might play a role in the susceptibility of P. aeruginosa to meropenem.
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Affiliation(s)
- Francisco Salvà-Serra
- Department of Infectious Diseases, Institute for Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden,Department of Clinical Microbiology, Sahlgrenska University Hospital, Gothenburg, Sweden,Culture Collection University of Gothenburg (CCUG), Department of Clinical Microbiology, Sahlgrenska University Hospital and Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden,Centre for Antibiotic Resistance Research (CARe), University of Gothenburg, Gothenburg, Sweden,Microbiology, Department of Biology, University of the Balearic Islands, Palma de Mallorca, Spain,*Correspondence: Francisco Salvà-Serra, ✉
| | - Daniel Jaén-Luchoro
- Department of Infectious Diseases, Institute for Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden,Culture Collection University of Gothenburg (CCUG), Department of Clinical Microbiology, Sahlgrenska University Hospital and Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden,Centre for Antibiotic Resistance Research (CARe), University of Gothenburg, Gothenburg, Sweden
| | | | - Ingegerd Adlerberth
- Department of Infectious Diseases, Institute for Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden,Department of Clinical Microbiology, Sahlgrenska University Hospital, Gothenburg, Sweden,Centre for Antibiotic Resistance Research (CARe), University of Gothenburg, Gothenburg, Sweden
| | - Edward R. B. Moore
- Department of Infectious Diseases, Institute for Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden,Department of Clinical Microbiology, Sahlgrenska University Hospital, Gothenburg, Sweden,Culture Collection University of Gothenburg (CCUG), Department of Clinical Microbiology, Sahlgrenska University Hospital and Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden,Centre for Antibiotic Resistance Research (CARe), University of Gothenburg, Gothenburg, Sweden
| | - Roger Karlsson
- Department of Infectious Diseases, Institute for Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden,Department of Clinical Microbiology, Sahlgrenska University Hospital, Gothenburg, Sweden,Centre for Antibiotic Resistance Research (CARe), University of Gothenburg, Gothenburg, Sweden,Nanoxis Consulting AB, Gothenburg, Sweden,Roger Karlsson, ✉
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5
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Chagas MDS, Medeiros F, dos Santos MT, de Menezes MA, Carvalho-Assef APD, da Silva FAB. An updated gene regulatory network reconstruction of multidrug-resistant Pseudomonas aeruginosa CCBH4851. Mem Inst Oswaldo Cruz 2022; 117:e220111. [PMID: 36259790 PMCID: PMC9565603 DOI: 10.1590/0074-02760220111] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 09/09/2022] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND Healthcare-associated infections due to multidrug-resistant (MDR) bacteria such as Pseudomonas aeruginosa are significant public health issues worldwide. A system biology approach can help understand bacterial behaviour and provide novel ways to identify potential therapeutic targets and develop new drugs. Gene regulatory networks (GRN) are examples of in silico representation of interaction between regulatory genes and their targets. OBJECTIVES In this work, we update the MDR P. aeruginosa CCBH4851 GRN reconstruction and analyse and discuss its structural properties. METHODS We based this study on the gene orthology inference methodology using the reciprocal best hit method. The P. aeruginosa CCBH4851 genome and GRN, published in 2019, and the P. aeruginosa PAO1 GRN, published in 2020, were used for this update reconstruction process. FINDINGS Our result is a GRN with a greater number of regulatory genes, target genes, and interactions compared to the previous networks, and its structural properties are consistent with the complexity of biological networks and the biological features of P. aeruginosa. MAIN CONCLUSIONS Here, we present the largest and most complete version of P. aeruginosa GRN published to this date, to the best of our knowledge.
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Affiliation(s)
- Márcia da Silva Chagas
- Fundação Oswaldo Cruz-Fiocruz, Programa de Computação Científica, Rio de Janeiro, RJ, Brasil,+ Corresponding authors: /
| | - Fernando Medeiros
- Fundação Oswaldo Cruz-Fiocruz, Instituto Nacional de Infectologia, Laboratório de Pesquisa Clínica em Doenças Febris Agudas, Rio de Janeiro, RJ, Brasil
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6
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Gheorghita AA, Wolfram F, Whitfield GB, Jacobs HM, Pfoh R, Wong SSY, Guitor AK, Goodyear MC, Berezuk AM, Khursigara CM, Parsek MR, Howell PL. The Pseudomonas aeruginosa homeostasis enzyme AlgL clears the periplasmic space of accumulated alginate during polymer biosynthesis. J Biol Chem 2022; 298:101560. [PMID: 34990713 PMCID: PMC8829089 DOI: 10.1016/j.jbc.2021.101560] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 12/27/2021] [Accepted: 12/28/2021] [Indexed: 11/24/2022] Open
Abstract
Pseudomonas aeruginosa is an opportunistic human pathogen and a leading cause of chronic infection in the lungs of individuals with cystic fibrosis. After colonization, P. aeruginosa often undergoes a phenotypic conversion to mucoidy, characterized by overproduction of the alginate exopolysaccharide. This conversion is correlated with poorer patient prognoses. The majority of genes required for alginate synthesis, including the alginate lyase, algL, are located in a single operon. Previous investigations of AlgL have resulted in several divergent hypotheses regarding the protein’s role in alginate production. To address these discrepancies, we determined the structure of AlgL and, using multiple sequence alignments, identified key active site residues involved in alginate binding and catalysis. In vitro enzymatic analysis of active site mutants highlights R249 and Y256 as key residues required for alginate lyase activity. In a genetically engineered P. aeruginosa strain where alginate biosynthesis is under arabinose control, we found that AlgL is required for cell viability and maintaining membrane integrity during alginate production. We demonstrate that AlgL functions as a homeostasis enzyme to clear the periplasmic space of accumulated polymer. Constitutive expression of the AlgU/T sigma factor mitigates the effects of an algL deletion during alginate production, suggesting that an AlgU/T-regulated protein or proteins can compensate for an algL deletion. Together, our study demonstrates the role of AlgL in alginate biosynthesis, explains the discrepancies observed previously across other P. aeruginosa ΔalgL genetic backgrounds, and clarifies the existing divergent data regarding the function of AlgL as an alginate degrading enzyme.
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Affiliation(s)
- Andreea A Gheorghita
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada; Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Francis Wolfram
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Gregory B Whitfield
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada; Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Holly M Jacobs
- Molecular and Cellular Biology Graduate Program, University of Washington, Seattle, Washington, USA
| | - Roland Pfoh
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Steven S Y Wong
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada; Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Allison K Guitor
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Mara C Goodyear
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Alison M Berezuk
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Cezar M Khursigara
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Matthew R Parsek
- Department of Microbiology, University of Washington, Seattle, Washington, USA
| | - P Lynne Howell
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada; Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada.
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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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Kim SK, Ngo HX, Dennis EK, Thamban Chandrika N, DeShong P, Garneau-Tsodikova S, Lee VT. Inhibition of Pseudomonas aeruginosa Alginate Synthesis by Ebselen Oxide and Its Analogues. ACS Infect Dis 2021; 7:1713-1726. [PMID: 33871968 DOI: 10.1021/acsinfecdis.1c00045] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen that is frequently found in the airways of cystic fibrosis (CF) patients due to the dehydrated mucus that collapses the underlying cilia and prevents mucociliary clearance. During this life-long chronic infection, P. aeruginosa cell accumulates mutations that lead to inactivation of the mucA gene that results in the constitutive expression of algD-algA operon and the production of alginate exopolysaccharide. The viscous alginate polysaccharide further occludes the airways of CF patients and serves as a protective matrix to shield P. aeruginosa from host immune cells and antibiotic therapy. Development of inhibitors of alginate production by P. aeruginosa would reduce the negative impact from this viscous polysaccharide. In addition to transcriptional regulation, alginate biosynthesis requires allosteric activation by bis (3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP) binding to an Alg44 protein. Previously, we found that ebselen (Eb) and ebselen oxide (EbO) inhibited diguanylate cyclase from synthesizing c-di-GMP. In this study, we show that EbO, Eb, ebsulfur (EbS), and their analogues inhibit alginate production. Eb and EbS can covalently modify the cysteine 98 (C98) residue of Alg44 and prevent its ability to bind c-di-GMP. However, P. aeruginosa with Alg44 C98 substituted with alanine or serine was still inhibited for alginate production by Eb and EbS. Our results indicate that EbO, Eb, and EbS are lead compounds for reducing alginate production by P. aeruginosa. Future development of these inhibitors could provide a potential treatment for CF patients infected with mucoid P. aeruginosa.
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Affiliation(s)
- Soo-Kyoung Kim
- Department of Cell Biology and Molecular Genetics, University of Maryland at College Park, College Park, Maryland 20742, United States
| | - Huy X. Ngo
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, Kentucky 40536, United States
| | - Emily K. Dennis
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, Kentucky 40536, United States
| | - Nishad Thamban Chandrika
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, Kentucky 40536, United States
| | - Philip DeShong
- Department of Chemistry and Biochemistry, University of Maryland at College Park, College Park, Maryland 20742, United States
| | - Sylvie Garneau-Tsodikova
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, Kentucky 40536, United States
| | - Vincent T. Lee
- Department of Cell Biology and Molecular Genetics, University of Maryland at College Park, College Park, Maryland 20742, United States
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9
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Schofield MC, Rodriguez DQ, Kidman AA, Cassin EK, Michaels LA, Campbell EA, Jorth PA, Tseng BS. The anti-sigma factor MucA is required for viability in Pseudomonas aeruginosa. Mol Microbiol 2021; 116:550-563. [PMID: 33905139 PMCID: PMC10069406 DOI: 10.1111/mmi.14732] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 04/21/2021] [Accepted: 04/21/2021] [Indexed: 12/16/2022]
Abstract
During decades-long infections in the cystic fibrosis (CF) airway, Pseudomonas aeruginosa undergoes selection. One bacterial genetic adaptation often observed in CF isolates is mucA mutations. MucA inhibits the sigma factor AlgU. Mutations in mucA lead to AlgU misregulation, resulting in a mucoid phenotype that is associated with poor CF disease outcomes. Due to its ability to be mutated, mucA is assumed to be dispensable for bacterial viability. Here we show that, paradoxically, a portion of mucA is essential in P. aeruginosa. We demonstrate that mucA is no longer required in a strain lacking algU, that mucA alleles encoding for proteins that do not bind to AlgU are insufficient for viability, and that mucA is no longer essential in mutant strains containing AlgU variants with reduced sigma factor activity. Furthermore, we found that overexpression of algU prevents cell growth in the absence of MucA, and that this phenotype can be rescued by the overproduction of RpoD, the housekeeping sigma factor. Together, these results suggest that in the absence of MucA, the inability to regulate AlgU activity results in the loss of bacterial viability. Finally, we speculate that the essentiality of anti-sigma factors that regulate envelope function may be a widespread phenomenon in bacteria.
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Affiliation(s)
| | | | - Amanda A Kidman
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV, USA
| | - Erin K Cassin
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV, USA
| | - Lia A Michaels
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV, USA
| | - Elizabeth A Campbell
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY, USA
| | - Peter A Jorth
- Departments of Pathology and Laboratory Medicine, Medicine, and Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Boo Shan Tseng
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV, USA
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10
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Wicke L, Ponath F, Coppens L, Gerovac M, Lavigne R, Vogel J. Introducing differential RNA-seq mapping to track the early infection phase for Pseudomonas phage ɸKZ. RNA Biol 2020; 18:1099-1110. [PMID: 33103565 PMCID: PMC8244752 DOI: 10.1080/15476286.2020.1827785] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
As part of the ongoing renaissance of phage biology, more phage genomes are becoming available through DNA sequencing. However, our understanding of the transcriptome architecture that allows these genomes to be expressed during host infection is generally poor. Transcription start sites (TSSs) and operons have been mapped for very few phages, and an annotated global RNA map of a phage – alone or together with its infected host – is not available at all. Here, we applied differential RNA-seq (dRNA-seq) to study the early, host takeover phase of infection by assessing the transcriptome structure of Pseudomonas aeruginosa jumbo phage ɸKZ, a model phage for viral genetics and structural research. This map substantially expands the number of early expressed viral genes, defining TSSs that are active ten minutes after ɸKZ infection. Simultaneously, we record gene expression changes in the host transcriptome during this critical metabolism conversion. In addition to previously reported upregulation of genes associated with amino acid metabolism, we observe strong activation of genes with functions in biofilm formation (cdrAB) and iron storage (bfrB), as well as an activation of the antitoxin ParD. Conversely, ɸKZ infection rapidly down-regulates complexes IV and V of oxidative phosphorylation (atpCDGHF and cyoABCDE). Taken together, our data provide new insights into the transcriptional organization and infection process of the giant bacteriophage ɸKZ and adds a framework for the genome-wide transcriptomic analysis of phage–host interactions.
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Affiliation(s)
- Laura Wicke
- Institute for Molecular Infection Biology (IMIB), Medical Faculty, University of Würzburg, Würzburg, Germany.,Department of Biosystems, Laboratory of Gene Technology, KU Leuven, Leuven, Belgium
| | - Falk Ponath
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), Würzburg, Germany
| | - Lucas Coppens
- Department of Biosystems, Laboratory of Gene Technology, KU Leuven, Leuven, Belgium
| | - Milan Gerovac
- Institute for Molecular Infection Biology (IMIB), Medical Faculty, University of Würzburg, Würzburg, Germany
| | - Rob Lavigne
- Department of Biosystems, Laboratory of Gene Technology, KU Leuven, Leuven, Belgium
| | - Jörg Vogel
- Institute for Molecular Infection Biology (IMIB), Medical Faculty, University of Würzburg, Würzburg, Germany.,Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), Würzburg, Germany
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11
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Luo J, Li X, Zhang J, Feng A, Xia M, Zhou M. Global regulator engineering enhances bioelectricity generation in Pseudomonas aeruginosa-inoculated MFCs. Biosens Bioelectron 2020; 163:112269. [PMID: 32568691 DOI: 10.1016/j.bios.2020.112269] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2020] [Revised: 04/21/2020] [Accepted: 04/30/2020] [Indexed: 01/24/2023]
Abstract
The electricigens with high-electroactivity is essential for resolving the low electricity power output (EPT) of microbial fuel cells (MFCs). However, the manipulation by single functional genes shows limitation because electroactivity is a complex phenotype controlled by multiple genes. Herein, global regulator engineering (GRE) was developed to optimize the electroactivity of an isolated strain (Pseudomonas aeruginosa P3-A-11) using an exogenous global regulator IrrE (ionizing radiation resistance E linkage group) as an object. The GRE was implemented through in vitro random mutagenesis by error-prone PCR and in vivo high-through screening comprised of cultures color assay, PYO measurement and MFCs operation. Four mutants with higher electroactivity were obtained, among which, the mutant 11/M2-59 not only displayed the maximal power density, but also exhibited stronger salt tolerance, consequently showing good performance of MFCs in the presence of salt. Apart from the reduced internal resistance, the increase in phenazines amounts primarily contributed to EPT improvement, which was realized by enhancing the core biosynthesis pathway and affecting other pathways (such as central metabolism pathway, quorum sensing system, regulatory network). Notably, IrrE exerted its positive effect on electroactivity even without native regulators (such as PmpR and RpoS). In addition, the significant fluctuations in expression levels of stress-responsive genes mediated by GRE were closely associated with the enhanced salt tolerance. This work demonstrated that GRE was an effective approach for simultaneously optimizing multiple phenotypes (such as electroactivity and stress tolerance), and thus would provide more opportunities to create high-efficiency electricigens and further promoted the practical application of MFCs.
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Affiliation(s)
- Jianmei Luo
- Key Laboratory of Industrial Fermentation Microbiology (Tianjin University of Science &Technology), Ministry of Education, Tianjin Key Lab of Industrial Microbiology, College of Biotechnology, Tianjin University of Science and Technology, Tianjin, 300457, PR China.
| | - Xiao Li
- Key Laboratory of Industrial Fermentation Microbiology (Tianjin University of Science &Technology), Ministry of Education, Tianjin Key Lab of Industrial Microbiology, College of Biotechnology, Tianjin University of Science and Technology, Tianjin, 300457, PR China
| | - Jingmei Zhang
- Key Laboratory of Industrial Fermentation Microbiology (Tianjin University of Science &Technology), Ministry of Education, Tianjin Key Lab of Industrial Microbiology, College of Biotechnology, Tianjin University of Science and Technology, Tianjin, 300457, PR China
| | - An Feng
- Key Laboratory of Industrial Fermentation Microbiology (Tianjin University of Science &Technology), Ministry of Education, Tianjin Key Lab of Industrial Microbiology, College of Biotechnology, Tianjin University of Science and Technology, Tianjin, 300457, PR China
| | - Menglei Xia
- Key Laboratory of Industrial Fermentation Microbiology (Tianjin University of Science &Technology), Ministry of Education, Tianjin Key Lab of Industrial Microbiology, College of Biotechnology, Tianjin University of Science and Technology, Tianjin, 300457, PR China
| | - Minghua Zhou
- Key Laboratory of Pollution Process and Environmental Criteria, Ministry of Education, Tianjin Key Laboratory of Urban Ecology Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin, 300350, PR China.
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12
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Abstract
In this issue of Journal of Bacteriology, Price et al. show that the Pseudomonas aeruginosa-produced exopolysaccharide alginate protects Staphylococcus aureus by dampening the expression of P. aeruginosa virulence products that usually inhibit S. aureus respiration and cell membrane integrity when the two organisms compete in other environments (C. E. Price, D. G. Brown, D. H. Limoli, V. V. Phelan, and G. A. O'Toole, J Bacteriol 202:e00559-19, 2020, https://doi.org/10.1128/jb.00559-19). This is the first report that exogenously added alginate affects P. aeruginosa competition and provides a partial explanation for S. aureus and P. aeruginosa coinfections in cystic fibrosis.
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13
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Guła G, Dorotkiewicz-Jach A, Korzekwa K, Valvano MA, Drulis-Kawa Z. Complex Signaling Networks Controlling Dynamic Molecular Changes in Pseudomonas aeruginosa Biofilm. Curr Med Chem 2019; 26:1979-1993. [PMID: 30207213 DOI: 10.2174/0929867325666180912110151] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 07/11/2018] [Accepted: 08/31/2018] [Indexed: 02/06/2023]
Abstract
The environment exerts strong influence on microbes. Adaptation of microbes to changing conditions is a dynamic process regulated by complex networks. Pseudomonas aeruginosa is a life-threating, versatile opportunistic and multi drug resistant pathogen that provides a model to investigate adaptation mechanisms to environmental changes. The ability of P. aeruginosa to form biofilms and to modify virulence in response to environmental changes is coordinated by various mechanisms including two-component systems (TCS), and secondary messengers involved in quorum sensing (QS) and c-di-GMP networks (diguanylate cyclase systems, DGC). In this review, we focus on the role of c-di-GMP during biofilm formation. We describe TCS and QS signal cascades regulated by c-di-GMP in response to changes in the external environment. We present a complex signaling network dynamically changing during the transition of P. aeruginosa from the free-living to sessile mode of growth.
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Affiliation(s)
- Grzegorz Guła
- Department of Pathogen Biology and Immunology, Institute of Genetics and Microbiology, University of Wroclaw, Przybyszewskiego 63/77, 51-148 Wroclaw, Poland
| | - Agata Dorotkiewicz-Jach
- Department of Pathogen Biology and Immunology, Institute of Genetics and Microbiology, University of Wroclaw, Przybyszewskiego 63/77, 51-148 Wroclaw, Poland
| | - Kamila Korzekwa
- Department of Microbiology, Institute of Genetics and Microbiology, University of Wroclaw, Przybyszewskiego 63/77, 51-148 Wroclaw, Poland
| | - Miguel A Valvano
- Wellcome- Wolfson Institute for Experimental Medicine, Queen's University Belfast, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7BL, United Kingdom
| | - Zuzanna Drulis-Kawa
- Department of Pathogen Biology and Immunology, Institute of Genetics and Microbiology, University of Wroclaw, Przybyszewskiego 63/77, 51-148 Wroclaw, Poland
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14
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Malhotra S, Hayes D, Wozniak DJ. Cystic Fibrosis and Pseudomonas aeruginosa: the Host-Microbe Interface. Clin Microbiol Rev 2019; 32:e00138-18. [PMID: 31142499 PMCID: PMC6589863 DOI: 10.1128/cmr.00138-18] [Citation(s) in RCA: 244] [Impact Index Per Article: 48.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
In human pathophysiology, the clash between microbial infection and host immunity contributes to multiple diseases. Cystic fibrosis (CF) is a classical example of this phenomenon, wherein a dysfunctional, hyperinflammatory immune response combined with chronic pulmonary infections wreak havoc upon the airway, leading to a disease course of substantial morbidity and shortened life span. Pseudomonas aeruginosa is an opportunistic pathogen that commonly infects the CF lung, promoting an accelerated decline of pulmonary function. Importantly, P. aeruginosa exhibits significant resistance to innate immune effectors and to antibiotics, in part, by expressing specific virulence factors (e.g., antioxidants and exopolysaccharides) and by acquiring adaptive mutations during chronic infection. In an effort to review our current understanding of the host-pathogen interface driving CF pulmonary disease, we discuss (i) the progression of disease within the primitive CF lung, specifically focusing on the role of host versus bacterial factors; (ii) critical, neutrophil-derived innate immune effectors that are implicated in CF pulmonary disease, including reactive oxygen species (ROS) and antimicrobial peptides (e.g., LL-37); (iii) P. aeruginosa virulence factors and adaptive mutations that enable evasion of the host response; and (iv) ongoing work examining the distribution and colocalization of host and bacterial factors within distinct anatomical niches of the CF lung.
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Affiliation(s)
- Sankalp Malhotra
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, Ohio, USA
- The Ohio State University College of Medicine, Columbus, Ohio, USA
| | - Don Hayes
- The Ohio State University College of Medicine, Columbus, Ohio, USA
- Department of Pediatrics, The Ohio State University, Columbus, Ohio, USA
- Section of Pulmonary Medicine, Nationwide Children's Hospital, Columbus, Ohio, USA
| | - Daniel J Wozniak
- The Ohio State University College of Medicine, Columbus, Ohio, USA
- Section of Pulmonary Medicine, Nationwide Children's Hospital, Columbus, Ohio, USA
- Department of Microbiology, The Ohio State University, Columbus, Ohio, USA
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15
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Ethanol Stimulates Trehalose Production through a SpoT-DksA-AlgU-Dependent Pathway in Pseudomonas aeruginosa. J Bacteriol 2019; 201:JB.00794-18. [PMID: 30936375 DOI: 10.1128/jb.00794-18] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 03/26/2019] [Indexed: 01/06/2023] Open
Abstract
Pseudomonas aeruginosa frequently resides among ethanol-producing microbes, making its response to the microbially produced concentrations of ethanol relevant to understanding its biology. Our transcriptome analysis found that genes involved in trehalose metabolism were induced by low concentrations of ethanol, and biochemical assays showed that levels of intracellular trehalose increased significantly upon growth with ethanol. The increase in trehalose was dependent on the TreYZ pathway but not other trehalose-metabolic enzymes (TreS or TreA). The sigma factor AlgU (AlgT), a homolog of RpoE in other species, was required for increased expression of the treZ gene and trehalose levels, but induction was not controlled by the well-characterized proteolysis of its anti-sigma factor, MucA. Growth with ethanol led to increased SpoT-dependent (p)ppGpp accumulation, which stimulates AlgU-dependent transcription of treZ and other AlgU-regulated genes through DksA, a (p)ppGpp and RNA polymerase binding protein. Ethanol stimulation of trehalose also required acylhomoserine lactone (AHL)-mediated quorum sensing (QS), as induction was not observed in a ΔlasR ΔrhlR strain. A network analysis using a model, eADAGE, built from publicly available P. aeruginosa transcriptome data sets (J. Tan, G. Doing, K. A. Lewis, C. E. Price, et al., Cell Syst 5:63-71, 2017, https://doi.org/10.1016/j.cels.2017.06.003) provided strong support for our model in which treZ and coregulated genes are controlled by both AlgU- and AHL-mediated QS. Consistent with (p)ppGpp- and AHL-mediated quorum-sensing regulation, ethanol, even when added at the time of culture inoculation, stimulated treZ transcript levels and trehalose production in cells from post-exponential-phase cultures but not in cells from exponential-phase cultures. These data highlight the integration of growth and cell density cues in the P. aeruginosa transcriptional response to ethanol.IMPORTANCE Pseudomonas aeruginosa is often found with bacteria and fungi that produce fermentation products, including ethanol. At concentrations similar to those produced by environmental microbes, we found that ethanol stimulated expression of trehalose-biosynthetic genes and cellular levels of trehalose, a disaccharide that protects against environmental stresses. The induction of trehalose by ethanol required the alternative sigma factor AlgU through DksA- and SpoT-dependent (p)ppGpp. Trehalose accumulation also required AHL quorum sensing and occurred only in post-exponential-phase cultures. This work highlights how cells integrate cell density and growth cues in their responses to products made by other microbes and reveals a new role for (p)ppGpp in the regulation of AlgU activity.
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16
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Polymorphonuclear Leukocytes or Hydrogen Peroxide Enhance Biofilm Development of Mucoid Pseudomonas aeruginosa. Mediators Inflamm 2018; 2018:8151362. [PMID: 30116152 PMCID: PMC6079396 DOI: 10.1155/2018/8151362] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Revised: 03/13/2018] [Accepted: 04/16/2018] [Indexed: 01/05/2023] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogenic bacterium involved in many human infections, including pneumonia, diabetic foot ulcers, and ventilator-associated pneumonia. P. aeruginosa cells usually undergo mucoid conversion during chronic lung infection in patients with cystic fibrosis (CF) and resist destruction by polymorphonuclear leukocytes (PMNs), which release free oxygen radicals (ROS), such as H2O2. PMNs are the main leucocytes in the CF sputum of patients who are infected with P. aeruginosa, which usually forms biofilms. Here, we report that PMNs or H2O2 can promote biofilm formation by mucoid P. aeruginosa FRD1 with the use of the hanging-peg method. The mucoid strain infecting CF patients overproduces alginate. In this study, PMNs and H2O2 promoted alginate production, and biofilms treated with PMNs or H2O2 exhibited higher expression of alginate genes. Additionally, PMNs increased the activity of GDP-mannose dehydrogenase, which is the key enzyme in alginate biosynthesis. Our results demonstrate that PMNs or H2O2 can enhance mucoid P. aeruginosa biofilms.
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17
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Chevalier S, Bouffartigues E, Bazire A, Tahrioui A, Duchesne R, Tortuel D, Maillot O, Clamens T, Orange N, Feuilloley MGJ, Lesouhaitier O, Dufour A, Cornelis P. Extracytoplasmic function sigma factors in Pseudomonas aeruginosa. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2018; 1862:706-721. [PMID: 29729420 DOI: 10.1016/j.bbagrm.2018.04.008] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Revised: 03/06/2018] [Accepted: 04/30/2018] [Indexed: 01/26/2023]
Abstract
The opportunistic pathogen Pseudomonas aeruginosa, like all members of the genus Pseudomonas, has the capacity to thrive in very different environments, ranging from water, plant roots, to animals, including humans to whom it can cause severe infections. This remarkable adaptability is reflected in the number of transcriptional regulators, including sigma factors in this bacterium. Among those, the 19 to 21 extracytoplasmic sigma factors (ECFσ) are endowed with different regulons and functions, including the iron starvation σ (PvdS, FpvI, HasI, FecI, FecI2 and others), the cell wall stress ECFσ AlgU, SigX and SbrI, and the unorthodox σVreI involved in the expression of virulence. Recently published data show that these ECFσ have separate regulons although presenting some cross-talk. We will present evidence that these different ECFσ are involved in the expression of different phenotypes, ranging from cell-wall stress response, production of extracellular polysaccharides, formation of biofilms, to iron acquisition.
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Affiliation(s)
- Sylvie Chevalier
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, Normandy University, University of Rouen, 27000 Evreux, France.
| | - Emeline Bouffartigues
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, Normandy University, University of Rouen, 27000 Evreux, France
| | - Alexis Bazire
- IUEM, Université de Bretagne-Sud (UBL), Laboratoire de Biotechnologie et Chimie Marines EA 3884, Lorient, France
| | - Ali Tahrioui
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, Normandy University, University of Rouen, 27000 Evreux, France
| | - Rachel Duchesne
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, Normandy University, University of Rouen, 27000 Evreux, France
| | - Damien Tortuel
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, Normandy University, University of Rouen, 27000 Evreux, France
| | - Olivier Maillot
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, Normandy University, University of Rouen, 27000 Evreux, France
| | - Thomas Clamens
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, Normandy University, University of Rouen, 27000 Evreux, France
| | - Nicole Orange
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, Normandy University, University of Rouen, 27000 Evreux, France
| | - Marc G J Feuilloley
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, Normandy University, University of Rouen, 27000 Evreux, France
| | - Olivier Lesouhaitier
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, Normandy University, University of Rouen, 27000 Evreux, France
| | - Alain Dufour
- IUEM, Université de Bretagne-Sud (UBL), Laboratoire de Biotechnologie et Chimie Marines EA 3884, Lorient, France
| | - Pierre Cornelis
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, Normandy University, University of Rouen, 27000 Evreux, France
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18
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Hudson J, Gardiner M, Deshpande N, Egan S. Transcriptional response of Nautella italica R11 towards its macroalgal host uncovers new mechanisms of host-pathogen interaction. Mol Ecol 2017; 27:1820-1832. [PMID: 29215165 DOI: 10.1111/mec.14448] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 11/21/2017] [Accepted: 11/24/2017] [Indexed: 12/14/2022]
Abstract
Macroalgae (seaweeds) are essential for the functioning of temperate marine ecosystems, but there is increasing evidence to suggest that their survival is under threat from anthropogenic stressors and disease. Nautella italica R11 is recognized as an aetiological agent of bleaching disease in the red alga, Delisea pulchra. Yet, there is a lack of knowledge surrounding the molecular mechanisms involved in this model host-pathogen interaction. Here we report that mutations in the gene encoding for a LuxR-type quorum sensing transcriptional regulator, RaiR, render N. italica R11 avirulent, suggesting this gene is important for regulating the expression of virulence phenotypes. Using an RNA sequencing approach, we observed a strong transcriptional response of N. italica R11 towards the presence of D. pulchra. In particular, genes involved in oxidative stress resistance, carbohydrate and central metabolism were upregulated in the presence of the host, suggesting a role for these functions in the opportunistic pathogenicity of N. italica R11. Furthermore, we show that RaiR regulates a subset of genes in N. italica R11, including those involved in metabolism and the expression of phage-related proteins. The outcome of this research reveals new functions important for virulence of N. italica R11 and contributes to our greater understanding of the complex factors mitigating microbial diseases in macroalgae.
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Affiliation(s)
- Jennifer Hudson
- School of Biological, Earth and Environmental Sciences, Centre for Marine Bio-Innovation, UNSW Sydney, Sydney, NSW, Australia
| | - Melissa Gardiner
- School of Biological, Earth and Environmental Sciences, Centre for Marine Bio-Innovation, UNSW Sydney, Sydney, NSW, Australia
| | - Nandan Deshpande
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, NSW, Australia
| | - Suhelen Egan
- School of Biological, Earth and Environmental Sciences, Centre for Marine Bio-Innovation, UNSW Sydney, Sydney, NSW, Australia
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19
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Regulation of ribonucleotide synthesis by the Pseudomonas aeruginosa two-component system AlgR in response to oxidative stress. Sci Rep 2017; 7:17892. [PMID: 29263410 PMCID: PMC5738425 DOI: 10.1038/s41598-017-17917-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Accepted: 12/04/2017] [Indexed: 11/11/2022] Open
Abstract
Ribonucleotide reductases (RNR) catalyze the last step of deoxyribonucleotide synthesis, and are therefore essential to DNA-based life. Three forms of RNR exist: classes I, II, and III. While eukaryotic cells use only class Ia RNR, bacteria can harbor any combination of classes, granting them adaptability. The opportunistic pathogen Pseudomonas aeruginosa surprisingly encodes all three classes, allowing it to thrive in different environments. Here we study an aspect of the complex RNR regulation whose molecular mechanism has never been elucidated, the well-described induction through oxidative stress, and link it to the AlgZR two-component system, the primary regulator of the mucoid phenotype. Through bioinformatics, we identify AlgR binding locations in RNR promoters, which we characterize functionally through EMSA and physically through AFM imaging. Gene reporter assays in different growth models are used to study the AlgZR-mediated control on the RNR network under various environmental conditions and physiological states. Thereby, we show that the two-component system AlgZR, which is crucial for bacterial conversion to the mucoid phenotype associated with chronic disease, controls the RNR network and directs how the DNA synthesis pathway is modulated in mucoid and non-mucoid biofilms, allowing it to respond to oxidative stress.
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20
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Woods EC, McBride SM. Regulation of antimicrobial resistance by extracytoplasmic function (ECF) sigma factors. Microbes Infect 2017; 19:238-248. [PMID: 28153747 DOI: 10.1016/j.micinf.2017.01.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 01/20/2017] [Accepted: 01/21/2017] [Indexed: 11/27/2022]
Abstract
Extracytoplasmic function (ECF) sigma factors are a subfamily of σ70 sigma factors that activate genes involved in stress-response functions. In many bacteria, ECF sigma factors regulate resistance to antimicrobial compounds. This review will summarize the ECF sigma factors that regulate antimicrobial resistance in model organisms and clinically relevant pathogens.
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Affiliation(s)
- Emily C Woods
- Department of Microbiology and Immunology, Emory Antibiotic Resistance Center, Emory University School of Medicine, Atlanta, GA, USA
| | - Shonna M McBride
- Department of Microbiology and Immunology, Emory Antibiotic Resistance Center, Emory University School of Medicine, Atlanta, GA, USA.
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21
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Affiliation(s)
- J.W. Costerton
- Center for Biofilm Engineering Montana State University 409 Cobleigh Hall Bozeman, Montana 59717
| | - Zbigniew Lewandowski
- Center for Biofilm Engineering Montana State University 409 Cobleigh Hall Bozeman, Montana 59717
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22
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Schulz S, Eckweiler D, Bielecka A, Nicolai T, Franke R, Dötsch A, Hornischer K, Bruchmann S, Düvel J, Häussler S. Elucidation of sigma factor-associated networks in Pseudomonas aeruginosa reveals a modular architecture with limited and function-specific crosstalk. PLoS Pathog 2015; 11:e1004744. [PMID: 25780925 PMCID: PMC4362757 DOI: 10.1371/journal.ppat.1004744] [Citation(s) in RCA: 105] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Accepted: 02/11/2015] [Indexed: 12/31/2022] Open
Abstract
Sigma factors are essential global regulators of transcription initiation in bacteria which confer promoter recognition specificity to the RNA polymerase core enzyme. They provide effective mechanisms for simultaneously regulating expression of large numbers of genes in response to challenging conditions, and their presence has been linked to bacterial virulence and pathogenicity. In this study, we constructed nine his-tagged sigma factor expressing and/or deletion mutant strains in the opportunistic pathogen Pseudomonas aeruginosa. To uncover the direct and indirect sigma factor regulons, we performed mRNA profiling, as well as chromatin immunoprecipitation coupled to high-throughput sequencing. We furthermore elucidated the de novo binding motif of each sigma factor, and validated the RNA- and ChIP-seq results by global motif searches in the proximity of transcriptional start sites (TSS). Our integrated approach revealed a highly modular network architecture which is composed of insulated functional sigma factor modules. Analysis of the interconnectivity of the various sigma factor networks uncovered a limited, but highly function-specific, crosstalk which orchestrates complex cellular processes. Our data indicate that the modular structure of sigma factor networks enables P. aeruginosa to function adequately in its environment and at the same time is exploited to build up higher-level functions by specific interconnections that are dominated by a participation of RpoN. Pseudomonas aeruginosa is well known for its high adaptability to a large range of environmental conditions, including those encountered within the human host. Transcription initiation represents a major regulatory target which drives versatility, and enables bacterial adaptation to challenging conditions and expression of virulence and pathogenicity. In bacteria, this process is largely orchestrated by sigma factors. Here, we performed an integrative approach, and by the combined use of three global profiling technologies uncovered the networks of 10 alternative sigma factors in the opportunistic pathogen P. aeruginosa. We demonstrate that these networks largely represent self-contained functional modules which exhibit a limited but highly specific crosstalk to build up higher-level functions. Our results do not only give extensive information on sigma factor binding sites throughout the P. aeruginosa genome, but also advance the understanding of sigma factor network architecture which provides bacteria with a framework to function adequately in their environment.
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Affiliation(s)
- Sebastian Schulz
- Institute for Molecular Bacteriology, TWINCORE GmbH, Center for Clinical and Experimental Infection Research, a joint venture of the Hannover Medical School and the Helmholtz Centre for Infection Research, Hannover, Germany
- Department of Molecular Bacteriology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Denitsa Eckweiler
- Institute for Molecular Bacteriology, TWINCORE GmbH, Center for Clinical and Experimental Infection Research, a joint venture of the Hannover Medical School and the Helmholtz Centre for Infection Research, Hannover, Germany
- Department of Molecular Bacteriology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Agata Bielecka
- Institute for Molecular Bacteriology, TWINCORE GmbH, Center for Clinical and Experimental Infection Research, a joint venture of the Hannover Medical School and the Helmholtz Centre for Infection Research, Hannover, Germany
- Department of Molecular Bacteriology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Tanja Nicolai
- Department of Molecular Bacteriology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Raimo Franke
- Department of Chemical Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Andreas Dötsch
- Institute for Molecular Bacteriology, TWINCORE GmbH, Center for Clinical and Experimental Infection Research, a joint venture of the Hannover Medical School and the Helmholtz Centre for Infection Research, Hannover, Germany
- Department of Molecular Bacteriology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Klaus Hornischer
- Institute for Molecular Bacteriology, TWINCORE GmbH, Center for Clinical and Experimental Infection Research, a joint venture of the Hannover Medical School and the Helmholtz Centre for Infection Research, Hannover, Germany
- Department of Molecular Bacteriology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Sebastian Bruchmann
- Institute for Molecular Bacteriology, TWINCORE GmbH, Center for Clinical and Experimental Infection Research, a joint venture of the Hannover Medical School and the Helmholtz Centre for Infection Research, Hannover, Germany
- Department of Molecular Bacteriology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Juliane Düvel
- Institute for Molecular Bacteriology, TWINCORE GmbH, Center for Clinical and Experimental Infection Research, a joint venture of the Hannover Medical School and the Helmholtz Centre for Infection Research, Hannover, Germany
- Department of Molecular Bacteriology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Susanne Häussler
- Institute for Molecular Bacteriology, TWINCORE GmbH, Center for Clinical and Experimental Infection Research, a joint venture of the Hannover Medical School and the Helmholtz Centre for Infection Research, Hannover, Germany
- Department of Molecular Bacteriology, Helmholtz Centre for Infection Research, Braunschweig, Germany
- * E-mail:
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Expression analysis of the Pseudomonas aeruginosa AlgZR two-component regulatory system. J Bacteriol 2014; 197:736-48. [PMID: 25488298 DOI: 10.1128/jb.02290-14] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pseudomonas aeruginosa virulence components are subject to complex regulatory control primarily through two-component regulatory systems that allow for sensing and responding to environmental stimuli. In this study, the expression and regulation of the P. aeruginosa AlgZR two-component regulatory system were examined. Primer extension and S1 nuclease protection assays were used to identify two transcriptional initiation sites for algR within the algZ coding region, and two additional start sites were identified upstream of the algZ coding region. The two algR transcriptional start sites, RT1 and RT2, are directly regulated by AlgU, consistent with previous reports of increased algR expression in mucoid backgrounds, and RpoS additionally plays a role in algR transcription. The expression of the first algZ promoter, ZT1, is entirely dependent upon Vfr for expression, whereas Vfr, RpoS, or AlgU does not regulate the second algZ promoter, ZT2. Western blot, real-time quantitative PCR (RT-qPCR), and transcriptional fusion analyses show that algZR expression is Vfr dependent. The algZ and algR genes also are cotranscribed in both nonmucoid and mucoid backgrounds. Furthermore, algZR was found to be cotranscribed with hemCD by RT-PCR. RT-qPCR confirmed that hemC transcription in the PAO1 ΔalgZ mutant was 40% of the level of the wild-type strain. Taken together, these results indicate that algZR transcription involves multiple factors at multiple start sites that control individual gene expression as well as coexpression of this two-component system with heme biosynthetic genes.
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Ferrara S, Carloni S, Fulco R, Falcone M, Macchi R, Bertoni G. Post-transcriptional regulation of the virulence-associated enzyme AlgC by the σ(22) -dependent small RNA ErsA of Pseudomonas aeruginosa. Environ Microbiol 2014; 17:199-214. [PMID: 25186153 DOI: 10.1111/1462-2920.12590] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Accepted: 07/29/2014] [Indexed: 11/30/2022]
Abstract
The small RNA ErsA of Pseudomonas aeruginosa, transcribed from the same genomic context of the well-known Escherichia coli Spot 42, has been characterized. We show that, different from Spot 42, ErsA is under the transcriptional control of the envelope stress response, which is known to impact the pathogenesis of P. aeruginosa through the activity of the alternative sigma factor σ(22) . The transcriptional responsiveness of ErsA RNA also spans infection-relevant cues that P. aeruginosa can experience in mammalian hosts, such as limited iron availability, temperature shifts from environmental to body temperature and reduced oxygen conditions. Another difference between Spot 42 and ErsA is that ErsA does not seem to be involved in the regulation of carbon source catabolism. Instead, our results suggest that ErsA is linked to anabolic functions for the synthesis of exoproducts from sugar precursors. We show that ErsA directly operates in the negative post-transcriptional regulation of the algC gene that encodes the virulence-associated enzyme AlgC, which provides sugar precursors for the synthesis of several P. aeruginosa polysaccharides. Like ErsA, the activation of algC expression is also dependent on σ(22) . Altogether, our results suggest that ErsA and σ(22) combine in an incoherent feed-forward loop to fine-tune AlgC enzyme expression.
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Affiliation(s)
- Silvia Ferrara
- Department of Biosciences, Università degli Studi di Milano, Milano, Italy
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Okkotsu Y, Little AS, Schurr MJ. The Pseudomonas aeruginosa AlgZR two-component system coordinates multiple phenotypes. Front Cell Infect Microbiol 2014; 4:82. [PMID: 24999454 PMCID: PMC4064291 DOI: 10.3389/fcimb.2014.00082] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Accepted: 06/02/2014] [Indexed: 01/28/2023] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen that causes a multitude of infections. These infections can occur at almost any site in the body and are usually associated with a breach of the innate immune system. One of the prominent sites where P. aeruginosa causes chronic infections is within the lungs of cystic fibrosis patients. P. aeruginosa uses two-component systems that sense environmental changes to differentially express virulence factors that cause both acute and chronic infections. The P. aeruginosa AlgZR two component system is one of its global regulatory systems that affects the organism's fitness in a broad manner. This two-component system is absolutely required for two P. aeruginosa phenotypes: twitching motility and alginate production, indicating its importance in both chronic and acute infections. Additionally, global transcriptome analyses indicate that it regulates the expression of many different genes, including those associated with quorum sensing, type IV pili, type III secretion system, anaerobic metabolism, cyanide and rhamnolipid production. This review examines the complex AlgZR regulatory network, what is known about the structure and function of each protein, and how it relates to the organism's ability to cause infections.
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Affiliation(s)
- Yuta Okkotsu
- Department of Microbiology, University of Colorado School of Medicine Aurora, CO, USA
| | - Alexander S Little
- Department of Microbiology, University of Colorado School of Medicine Aurora, CO, USA
| | - Michael J Schurr
- Department of Microbiology, University of Colorado School of Medicine Aurora, CO, USA
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Ryall B, Carrara M, Zlosnik JEA, Behrends V, Lee X, Wong Z, Lougheed KE, Williams HD. The mucoid switch in Pseudomonas aeruginosa represses quorum sensing systems and leads to complex changes to stationary phase virulence factor regulation. PLoS One 2014; 9:e96166. [PMID: 24852379 PMCID: PMC4031085 DOI: 10.1371/journal.pone.0096166] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Accepted: 04/03/2014] [Indexed: 01/04/2023] Open
Abstract
The opportunistic pathogen Pseudomonas aeruginosa chronically infects the airways of Cystic Fibrosis (CF) patients during which it adapts and undergoes clonal expansion within the lung. It commonly acquires inactivating mutations of the anti-sigma factor MucA leading to a mucoid phenotype, caused by excessive production of the extracellular polysaccharide alginate that is associated with a decline in lung function. Alginate production is believed to be the key benefit of mucA mutations to the bacterium in the CF lung. A phenotypic and gene expression characterisation of the stationary phase physiology of mucA22 mutants demonstrated complex and subtle changes in virulence factor production, including cyanide and pyocyanin, that results in their down-regulation upon entry into stationary phase but, (and in contrast to wildtype strains) continued production in prolonged stationary phase. These findings may have consequences for chronic infection if mucoid P. aeruginosa were to continue to make virulence factors under non-growing conditions during infection. These changes resulted in part from a severe down-regulation of both AHL-and AQ (PQS)-dependent quorum sensing systems. In trans expression of the cAMP-dependent transcription factor Vfr restored both quorum sensing defects and virulence factor production in early stationary phase. Our findings have implications for understanding the evolution of P. aeruginosa during CF lung infection and it demonstrates that mucA22 mutation provides a second mechanism, in addition to the commonly occurring lasR mutations, of down-regulating quorum sensing during chronic infection this may provide a selection pressure for the mucoid switch in the CF lung.
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Affiliation(s)
- Ben Ryall
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, Sir Alexander Fleming Building, London, United Kingdom
| | - Marta Carrara
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, Sir Alexander Fleming Building, London, United Kingdom
| | - James E. A. Zlosnik
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, Sir Alexander Fleming Building, London, United Kingdom
| | - Volker Behrends
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, Sir Alexander Fleming Building, London, United Kingdom
- Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, Sir Alexander Fleming Building, London, United Kingdom
| | - Xiaoyun Lee
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, Sir Alexander Fleming Building, London, United Kingdom
| | - Zhen Wong
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, Sir Alexander Fleming Building, London, United Kingdom
| | - Kathryn E. Lougheed
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, Sir Alexander Fleming Building, London, United Kingdom
| | - Huw D. Williams
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, Sir Alexander Fleming Building, London, United Kingdom
- * E-mail:
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Park SH, Bao Z, Butcher BG, D'Amico K, Xu Y, Stodghill P, Schneider DJ, Cartinhour S, Filiatrault MJ. Analysis of the small RNA spf in the plant pathogen Pseudomonas syringae pv. tomato strain DC3000. MICROBIOLOGY-SGM 2014; 160:941-953. [PMID: 24600027 DOI: 10.1099/mic.0.076497-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Bacteria contain small non-coding RNAs (ncRNAs) that are typically responsible for altering transcription, translation or mRNA stability. ncRNAs are important because they often regulate virulence factors and susceptibility to various stresses. Here, the regulation of a recently described ncRNA of Pseudomonas syringae DC3000, spot 42 (now referred to as spf), was investigated. A putative RpoE binding site was identified upstream of spf in strain DC3000. RpoE is shown to regulate the expression of spf. Also, deletion of spf results in increased sensitivity to hydrogen peroxide compared with the wild-type strain, suggesting that spf plays a role in susceptibility to oxidative stress. Furthermore, expression of alg8 is shown to be influenced by spf, suggesting that this ncRNA plays a role in alginate biosynthesis. Structural and comparative genomic analyses show this ncRNA is well conserved among the pseudomonads. The findings provide new information on the regulation and role of this ncRNA in P. syringae.
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Affiliation(s)
- So Hae Park
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY 14853, USA
| | - Zhongmeng Bao
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY 14853, USA
| | - Bronwyn G Butcher
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY 14853, USA
| | - Katherine D'Amico
- Plant-Microbe Interactions Research Unit, Robert W. Holley Center for Agriculture and Health, Agricultural Research Service, United States Department of Agriculture, Ithaca, NY 14853, USA.,Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY 14853, USA
| | - Yun Xu
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY 14853, USA
| | - Paul Stodghill
- Plant-Microbe Interactions Research Unit, Robert W. Holley Center for Agriculture and Health, Agricultural Research Service, United States Department of Agriculture, Ithaca, NY 14853, USA
| | - David J Schneider
- Plant-Microbe Interactions Research Unit, Robert W. Holley Center for Agriculture and Health, Agricultural Research Service, United States Department of Agriculture, Ithaca, NY 14853, USA.,Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY 14853, USA
| | - Samuel Cartinhour
- Plant-Microbe Interactions Research Unit, Robert W. Holley Center for Agriculture and Health, Agricultural Research Service, United States Department of Agriculture, Ithaca, NY 14853, USA.,Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY 14853, USA
| | - M J Filiatrault
- Plant-Microbe Interactions Research Unit, Robert W. Holley Center for Agriculture and Health, Agricultural Research Service, United States Department of Agriculture, Ithaca, NY 14853, USA.,Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY 14853, USA
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Yin Y, Damron FH, Withers TR, Pritchett CL, Wang X, Schurr MJ, Yu HD. Expression of mucoid induction factor MucE is dependent upon the alternate sigma factor AlgU in Pseudomonas aeruginosa. BMC Microbiol 2013; 13:232. [PMID: 24138584 PMCID: PMC3819740 DOI: 10.1186/1471-2180-13-232] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Accepted: 10/09/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Alginate overproduction in P. aeruginosa, also referred to as mucoidy, is a poor prognostic marker for patients with cystic fibrosis (CF). We previously reported the construction of a unique mucoid strain which overexpresses a small envelope protein MucE leading to activation of the protease AlgW. AlgW then degrades the anti-sigma factor MucA thus releasing the alternative sigma factor AlgU/T (σ(22)) to initiate transcription of the alginate biosynthetic operon. RESULTS In the current study, we mapped the mucE transcriptional start site, and determined that P(mucE) activity was dependent on AlgU. Additionally, the presence of triclosan and sodium dodecyl sulfate was shown to cause an increase in P(mucE) activity. It was observed that mucE-mediated mucoidy in CF isolates was dependent on both the size of MucA and the genotype of algU. We also performed shotgun proteomic analysis with cell lysates from the strains PAO1, VE2 (PAO1 with constitutive expression of mucE) and VE2ΔalgU (VE2 with in-frame deletion of algU). As a result, we identified nine algU-dependent and two algU-independent proteins that were affected by overexpression of MucE. CONCLUSIONS Our data indicates there is a positive feedback regulation between MucE and AlgU. Furthermore, it seems likely that MucE may be part of the signal transduction system that senses certain types of cell wall stress to P. aeruginosa.
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Affiliation(s)
| | | | | | | | | | | | - Hongwei D Yu
- Department of Biochemistry and Microbiology, Joan C, Edwards School of Medicine at Marshall University, Huntington, WV 25755, USA.
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29
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Which bacterial biofilm exopolysaccharide is preferred, Psl or alginate? J Bacteriol 2013; 195:1623-6. [PMID: 23417492 DOI: 10.1128/jb.00173-13] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Nambu T, Yamane K, Yamanaka T, Mashimo C, Maruyama H, Yoshida M, Hayashi H, Leung KP, Fukushima H. Identification of disulphide stress-responsive extracytoplasmic function sigma factors in Rothia mucilaginosa. Arch Oral Biol 2013; 58:681-9. [PMID: 23399044 DOI: 10.1016/j.archoralbio.2012.10.017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2012] [Revised: 08/21/2012] [Accepted: 10/23/2012] [Indexed: 11/17/2022]
Abstract
Rothia mucilaginosa is known as a member of commensal bacterial flora in the oral cavity and has received attention as a potential opportunistic pathogen. We previously determined the genomic sequence of R. mucilaginosa DY-18, a clinical strain with biofilm-like structures isolated from an infected root canal of a tooth with persistent apical periodontitis. We found that the DY-18 genome had only two sigma factor genes that encoded the primary and extracytoplasmic function (ECF) sigma factors. Genomic analysis on the available database of R. mucilaginosa ATCC 25296 (a type strain for R. mucilaginosa) revealed that ATCC 25296 has three sigma factors: one primary sigma factor and two ECF sigma factors, one of which was highly homologous to that of DY-18. ECF sigma factors play an important role in the response to environmental stress and to the production of virulence factors. Therefore, we first examined gene-encoding sigma factors on R. mucilaginosa genome in silico. The homologous ECF sigma factors found in strains DY-18 and ATCC 25296 formed a distinct SigH (SigR) clade in a phylogenetic tree and their cognate anti-sigma factor has a HXXXCXXC motif known to respond against disulphide stress. Quantitative reverse transcription polymerase chain reaction (PCR) and microarray analysis showed that the transcriptional levels of sigH were markedly up-regulated under disulphide stress in both strains. Microarray data also demonstrated that several oxidative-stress-related genes (thioredoxin, mycothione reductase, reductase and oxidoreductase) were significantly up-regulated under the diamide stress. On the basis of these results, we conclude that the alternative sigma factor SigH of R. mucilaginosa is a candidate regulator in the redox state.
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Affiliation(s)
- Takayuki Nambu
- Department of Bacteriology, Osaka Dental University, 8-1 Kuzuha-Hanazono, Hirakata, 573-1121 Japan.
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Giacani L, Denisenko O, Tompa M, Centurion-Lara A. Identification of the Treponema pallidum subsp. pallidum TP0092 (RpoE) regulon and its implications for pathogen persistence in the host and syphilis pathogenesis. J Bacteriol 2013; 195:896-907. [PMID: 23243302 PMCID: PMC3562100 DOI: 10.1128/jb.01973-12] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Accepted: 12/06/2012] [Indexed: 12/16/2022] Open
Abstract
Bacteria often respond to harmful environmental stimuli with the induction of extracytoplasmic function (ECF) sigma (σ) factors that in turn direct RNA polymerase to transcribe specific groups of response genes (or regulons) to minimize cellular damage and favor adaptation to the changed extracellular milieu. In Treponema pallidum subsp. pallidum, the agent of syphilis, the TP0092 gene is predicted to code for the pathogen's only annotated ECF σ factor, homologous to RpoE, known in Escherichia coli to control a key transduction pathway for maintenance of envelope homeostasis in response to external stress and cell growth. Here we have shown that TP0092 is highly transcribed during experimental syphilis. Furthermore, TP0092 transcription levels significantly increase as infection progresses toward immune clearance of the pathogen, suggesting a role for TP0092 in helping T. pallidum respond to harmful stimuli in the host environment. To investigate this hypothesis, we determined the TP0092 regulon at two different time points during infection using chromatin immunoprecipitation followed by high-throughput sequencing. A total of 22 chromosomal regions, all containing putative TP0092-binding sites and corresponding to as many T. pallidum genes, were identified. Noteworthy among them are the genes encoding desulfoferrodoxin and thioredoxin, involved in detoxification of reactive oxygen species (ROS). Because T. pallidum does not possess other enzymes for ROS detoxification, such as superoxide dismutase, catalase, or glutathione peroxidase, our results suggest that the TP0092 regulon is important in protecting the syphilis spirochete from damage caused by ROS produced at the site of infection during the inflammatory response.
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Affiliation(s)
- Lorenzo Giacani
- Departments of Medicine, University of Washington, Seattle, WA, USA.
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Folkesson A, Jelsbak L, Yang L, Johansen HK, Ciofu O, Høiby N, Molin S. Adaptation of Pseudomonas aeruginosa to the cystic fibrosis airway: an evolutionary perspective. Nat Rev Microbiol 2012; 10:841-51. [DOI: 10.1038/nrmicro2907] [Citation(s) in RCA: 513] [Impact Index Per Article: 42.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Balasubramanian D, Schneper L, Kumari H, Mathee K. A dynamic and intricate regulatory network determines Pseudomonas aeruginosa virulence. Nucleic Acids Res 2012; 41:1-20. [PMID: 23143271 PMCID: PMC3592444 DOI: 10.1093/nar/gks1039] [Citation(s) in RCA: 317] [Impact Index Per Article: 26.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Pseudomonas aeruginosa is a metabolically versatile bacterium that is found in a wide range of biotic and abiotic habitats. It is a major human opportunistic pathogen causing numerous acute and chronic infections. The critical traits contributing to the pathogenic potential of P. aeruginosa are the production of a myriad of virulence factors, formation of biofilms and antibiotic resistance. Expression of these traits is under stringent regulation, and it responds to largely unidentified environmental signals. This review is focused on providing a global picture of virulence gene regulation in P. aeruginosa. In addition to key regulatory pathways that control the transition from acute to chronic infection phenotypes, some regulators have been identified that modulate multiple virulence mechanisms. Despite of a propensity for chaotic behaviour, no chaotic motifs were readily observed in the P. aeruginosa virulence regulatory network. Having a ‘birds-eye’ view of the regulatory cascades provides the forum opportunities to pose questions, formulate hypotheses and evaluate theories in elucidating P. aeruginosa pathogenesis. Understanding the mechanisms involved in making P. aeruginosa a successful pathogen is essential in helping devise control strategies.
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Affiliation(s)
- Deepak Balasubramanian
- Department of Biological Sciences, College of Arts and Science, Florida International University, Miami, FL 33199, USA
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Balasubramanian D, Schneper L, Merighi M, Smith R, Narasimhan G, Lory S, Mathee K. The regulatory repertoire of Pseudomonas aeruginosa AmpC ß-lactamase regulator AmpR includes virulence genes. PLoS One 2012; 7:e34067. [PMID: 22479525 PMCID: PMC3315558 DOI: 10.1371/journal.pone.0034067] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2011] [Accepted: 02/27/2012] [Indexed: 01/19/2023] Open
Abstract
In Enterobacteriaceae, the transcriptional regulator AmpR, a member of the LysR family, regulates the expression of a chromosomal β-lactamase AmpC. The regulatory repertoire of AmpR is broader in Pseudomonas aeruginosa, an opportunistic pathogen responsible for numerous acute and chronic infections including cystic fibrosis. In addition to regulating ampC, P. aeruginosa AmpR regulates the sigma factor AlgT/U and production of some quorum sensing (QS)-regulated virulence factors. In order to better understand the ampR regulon, we compared the transcriptional profile generated using DNA microarrays of the prototypic P. aeruginosa PAO1 strain with its isogenic ampR deletion mutant, PAOΔampR. Transcriptome analysis demonstrates that the AmpR regulon is much more extensive than previously thought, with the deletion of ampR influencing the differential expression of over 500 genes. In addition to regulating resistance to β-lactam antibiotics via AmpC, AmpR also regulates non-β-lactam antibiotic resistance by modulating the MexEF-OprN efflux pump. Other virulence mechanisms including biofilm formation and QS-regulated acute virulence factors are AmpR-regulated. Real-time PCR and phenotypic assays confirmed the microarray data. Further, using a Caenorhabditis elegans model, we demonstrate that a functional AmpR is required for P. aeruginosa pathogenicity. AmpR, a member of the core genome, also regulates genes in the regions of genome plasticity that are acquired by horizontal gene transfer. Further, we show differential regulation of other transcriptional regulators and sigma factors by AmpR, accounting for the extensive AmpR regulon. The data demonstrates that AmpR functions as a global regulator in P. aeruginosa and is a positive regulator of acute virulence while negatively regulating biofilm formation, a chronic infection phenotype. Unraveling this complex regulatory circuit will provide a better understanding of the bacterial response to antibiotics and how the organism coordinately regulates a myriad of virulence factors in response to antibiotic exposure.
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Affiliation(s)
- Deepak Balasubramanian
- Department of Biological Sciences, College of Arts and Science, Florida International University, Miami, Florida, United States of America
| | - Lisa Schneper
- Molecular Microbiology and Infectious Diseases (Herbert Werthiem College of Medicine), Florida International University, Miami, Florida, United States of America
| | - Massimo Merighi
- Microbiology and Molecular Genetics, Harvard Medical School, Boston, Massachussetts, United States of America
| | - Roger Smith
- Microbiology and Molecular Genetics, Harvard Medical School, Boston, Massachussetts, United States of America
| | - Giri Narasimhan
- School of Computing and Information Science, College of Engineering and Computing, Florida International University, Miami, Florida, United States of America
| | - Stephen Lory
- Microbiology and Molecular Genetics, Harvard Medical School, Boston, Massachussetts, United States of America
| | - Kalai Mathee
- Molecular Microbiology and Infectious Diseases (Herbert Werthiem College of Medicine), Florida International University, Miami, Florida, United States of America
- * E-mail:
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Sautter R, Ramos D, Schneper L, Ciofu O, Wassermann T, Koh CL, Heydorn A, Hentzer M, Høiby N, Kharazmi A, Molin S, Devries CA, Ohman DE, Mathee K. A complex multilevel attack on Pseudomonas aeruginosa algT/U expression and algT/U activity results in the loss of alginate production. Gene 2011; 498:242-53. [PMID: 22088575 DOI: 10.1016/j.gene.2011.11.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2011] [Revised: 09/27/2011] [Accepted: 11/01/2011] [Indexed: 11/18/2022]
Abstract
Infection by the opportunistic pathogen Pseudomonas aeruginosa is a leading cause of morbidity and mortality seen in cystic fibrosis (CF) patients. This is mainly due to the genotypic and phenotypic changes of the bacteria that cause conversion from a typical nonmucoid to a mucoid form in the CF lung. Mucoid conversion is indicative of overproduction of a capsule-like polysaccharide called alginate. The alginate-overproducing (Alg(+)) mucoid phenotype seen in the CF isolates is extremely unstable. Low oxygen tension growth of mucoid variants readily selects for nonmucoid variants. The switching off mechanism has been mapped to the algT/U locus, and the molecular basis for this conversion was partially attributed to mutations in the algT/U gene itself. To further characterize molecular changes resulting in the unstable phenotype, an isogenic PAO1 derivative that is constitutively Alg(+) due to the replacement of the mucA with mucA22 (PDO300) was used. The mucA22 allele is common in mucoid CF isolates. Thirty-four spontaneous nonmucoid variants, or sap (suppressor of alginate production) mutants, of PDO300 were isolated under low oxygen tension. About 40% of the sap mutants were rescued by a plasmid carrying algT/U (Group A). The remaining sap mutants were not (Group B). The members of Group B fall into two subsets: one similar to PAO1, and another comparable to PDO300. Sequence analysis of the algT/U and mucA genes in Group A shows that mucA22 is intact, whereas algT/U contains mutations. Genetic complementation and sequencing of one Group B sap mutant, sap22, revealed that the nonmucoid phenotype was due to the presence of a mutation in PA3257. PA3257 encodes a putative periplasmic protease. Mutation of PA3257 resulted in decreased algT/U expression. Thus, inhibition of algT/U is a primary mechanism for alginate synthesis suppression.
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Affiliation(s)
- Robert Sautter
- Department of Biological Sciences, College of Arts and Sciences, Florida International University, Miami, FL 33199, USA
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Franklin MJ, Nivens DE, Weadge JT, Howell PL. Biosynthesis of the Pseudomonas aeruginosa Extracellular Polysaccharides, Alginate, Pel, and Psl. Front Microbiol 2011; 2:167. [PMID: 21991261 PMCID: PMC3159412 DOI: 10.3389/fmicb.2011.00167] [Citation(s) in RCA: 343] [Impact Index Per Article: 26.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2011] [Accepted: 07/19/2011] [Indexed: 12/30/2022] Open
Abstract
Pseudomonas aeruginosa thrives in many aqueous environments and is an opportunistic pathogen that can cause both acute and chronic infections. Environmental conditions and host defenses cause differing stresses on the bacteria, and to survive in vastly different environments, P. aeruginosa must be able to adapt to its surroundings. One strategy for bacterial adaptation is to self-encapsulate with matrix material, primarily composed of secreted extracellular polysaccharides. P. aeruginosa has the genetic capacity to produce at least three secreted polysaccharides; alginate, Psl, and Pel. These polysaccharides differ in chemical structure and in their biosynthetic mechanisms. Since alginate is often associated with chronic pulmonary infections, its biosynthetic pathway is the best characterized. However, alginate is only produced by a subset of P. aeruginosa strains. Most environmental and other clinical isolates secrete either Pel or Psl. Little information is available on the biosynthesis of these polysaccharides. Here, we review the literature on the alginate biosynthetic pathway, with emphasis on recent findings describing the structure of alginate biosynthetic proteins. This information combined with the characterization of the domain architecture of proteins encoded on the Psl and Pel operons allowed us to make predictive models for the biosynthesis of these two polysaccharides. The results indicate that alginate and Pel share certain features, including some biosynthetic proteins with structurally or functionally similar properties. In contrast, Psl biosynthesis resembles the EPS/CPS capsular biosynthesis pathway of Escherichia coli, where the Psl pentameric subunits are assembled in association with an isoprenoid lipid carrier. These models and the environmental cues that cause the cells to produce predominantly one polysaccharide over the others are subjects of current investigation.
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Abstract
Gram-negative bacterial pathogens have evolved a number of virulence-promoting strategies including the production of extracellular polysaccharides such as alginate and the injection of effector proteins into host cells. The induction of these virulence mechanisms can be associated with concomitant downregulation of the abundance of proteins that trigger the host immune system, such as bacterial flagellin. In Pseudomonas syringae, we observed that bacterial motility and the abundance of flagellin were significantly reduced under conditions that induce the type III secretion system. To identify genes involved in this negative regulation, we conducted a forward genetic screen with P. syringae pv. maculicola ES4326 using motility as a screening phenotype. We identified the periplasmic protease AlgW as a key negative regulator of flagellin abundance that also positively regulates alginate biosynthesis and the type III secretion system. We also demonstrate that AlgW constitutes a major virulence determinant of P. syringae required to dampen plant immune responses. Our findings support the conclusion that P. syringae co-ordinately regulates virulence strategies through AlgW in order to effectively suppress host immunity.
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Affiliation(s)
- Karl J Schreiber
- Department of Cell & Systems Biology, University of Toronto, Toronto, ON M5S 3B2, Canada
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Roberts DP, Lohrke SM, McKenna L, Lakshman DK, Kong H, Lydon J. Mutation of a degS homologue in Enterobacter cloacae decreases colonization and biological control of damping-off on cucumber. PHYTOPATHOLOGY 2011; 101:271-280. [PMID: 20942652 DOI: 10.1094/phyto-03-10-0076] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We have been using mutagenesis to determine how biocontrol bacteria such as Enterobacter cloacae 501R3 deal with complex nutritional environments found in association with plants. E. cloacae C10, a mutant of 501R3 with a transposon insertion in degS, was diminished in growth on synthetic cucumber root exudate (SRE), colonization of cucumber seed and roots, and control of damping-off of cucumber caused by Pythium ultimum. DegS, a periplasmic serine protease in the closely related bacterium Escherichia coli K12, is required for the RpoE-mediated stress response. C10 containing wild-type degS from 501R3 or from E. coli K12 on pBeloBAC11 was significantly increased in growth on SRE, colonization of cucumber roots, and control of P. ultimum relative to C10 containing pBeloBAC11 alone. C10 and 501R3 were similar in sensitivity to acidic conditions, plant-derived phenolic compounds, oxidative stress caused by hydrogen peroxide, dessication, and high osmoticum; stress conditions potentially associated with plants. This study demonstrates a role for degS in the spermosphere and rhizosphere during colonization and disease control by Enterobacter cloacae. This study implicates, for the first time, the involvement of DegS and, by extension, the RpoE-mediated stress response, in reducing stress on E. cloacae resulting from the complex nutritional environments in the spermosphere and rhizosphere.
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Affiliation(s)
- Daniel P Roberts
- United States Department of Agriculture - Agriculture Research Service, Beltsville, MD, USA.
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Activation of the Pseudomonas aeruginosa AlgU regulon through mucA mutation inhibits cyclic AMP/Vfr signaling. J Bacteriol 2010; 192:5709-17. [PMID: 20817772 DOI: 10.1128/jb.00526-10] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen that causes acute, invasive infections in immunocompromised individuals and chronic, persistent respiratory infections in individuals with cystic fibrosis (CF). The differential progression of acute or chronic infections involves the production of distinct sets of virulence factors. P. aeruginosa strains isolated from patients with acute respiratory infection are generally nonencapsulated and express a variety of invasive virulence factors, including flagella, the type III secretion system (T3SS), type IV pili (TFP), and multiple secreted toxins and degradative enzymes. Strains isolated from chronically infected CF patients, however, typically lack expression of invasive virulence factors and have a mucoid phenotype due to the production of an alginate capsule. The mucoid phenotype results from loss-of-function mutations in mucA, which encodes an anti-sigma factor that normally prevents alginate synthesis. Here, we report that the cyclic AMP/Vfr-dependent signaling (CVS) pathway is defective in mucA mutants and that the defect occurs at the level of vfr expression. The CVS pathway regulates the expression of multiple invasive virulence factors, including T3SS, exotoxin A, protease IV, and TFP. We further demonstrate that mucA-dependent CVS inhibition involves the alternative sigma factor AlgU (AlgT) and the response regulator AlgR but does not depend on alginate production. Our findings show that a single naturally occurring mutation leads to inverse regulation of virulence factors involved in acute and persistent infections. These results suggest that mucoid conversion and inhibition of invasive virulence determinants may both confer a selective advantage to mucA mutant strains of P. aeruginosa in the CF lung.
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Sodium nitrite-mediated killing of the major cystic fibrosis pathogens Pseudomonas aeruginosa, Staphylococcus aureus, and Burkholderia cepacia under anaerobic planktonic and biofilm conditions. Antimicrob Agents Chemother 2010; 54:4671-7. [PMID: 20696868 DOI: 10.1128/aac.00379-10] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
A hallmark of airways in patients with cystic fibrosis (CF) is highly refractory, chronic infections by several opportunistic bacterial pathogens. A recent study demonstrated that acidified sodium nitrite (A-NO(2)(-)) killed the highly refractory mucoid form of Pseudomonas aeruginosa, a pathogen that significantly compromises lung function in CF patients (S. S. Yoon et al., J. Clin. Invest. 116:436-446, 2006). Therefore, the microbicidal activity of A-NO(2)(-) (pH 6.5) against the following three major CF pathogens was assessed: P. aeruginosa (a mucoid, mucA22 mutant and a sequenced nonmucoid strain, PAO1), Staphylococcus aureus USA300 (methicillin resistant), and Burkholderia cepacia, a notoriously antibiotic-resistant organism. Under planktonic, anaerobic conditions, growth of all strains except for P. aeruginosa PAO1 was inhibited by 7.24 mM (512 μg ml(-1) NO(2)(-)). B. cepacia was particularly sensitive to low concentrations of A-NO(2)(-) (1.81 mM) under planktonic conditions. In antibiotic-resistant communities known as biofilms, which are reminiscent of end-stage CF airway disease, A-NO(2)(-) killed mucoid P. aeruginosa, S. aureus, and B. cepacia; 1 to 2 logs of cells were killed after a 2-day incubation with a single dose of ∼15 mM A-NO(2)(-). Animal toxicology and phase I human trials indicate that these bactericidal levels of A-NO(2)(-) can be easily attained by aerosolization. Thus, in summary, we demonstrate that A-NO(2)(-) is very effective at killing these important CF pathogens and could be effective in other infectious settings, particularly under anaerobic conditions where bacterial defenses against the reduction product of A-NO(2)(-), nitric oxide (NO), are dramatically reduced.
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Hopman CTP, Speijer D, van der Ende A, Pannekoek Y. Identification of a novel anti-sigmaE factor in Neisseria meningitidis. BMC Microbiol 2010; 10:164. [PMID: 20525335 PMCID: PMC2893595 DOI: 10.1186/1471-2180-10-164] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2010] [Accepted: 06/04/2010] [Indexed: 08/30/2023] Open
Abstract
Background Fine tuning expression of genes is a prerequisite for the strictly human pathogen Neisseria meningitidis to survive hostile growth conditions and establish disease. Many bacterial species respond to stress by using alternative σ factors which, in complex with RNA polymerase holoenzyme, recognize specific promoter determinants. σE, encoded by rpoE (NMB2144) in meningococci, is known to be essential in mounting responses to environmental challenges in many pathogens. Here we identified genes belonging to the σE regulon of meningococci. Results We show that meningococcal σE is part of the polycistronic operon NMB2140-NMB2145 and autoregulated. In addition we demonstrate that σE controls expression of methionine sulfoxide reductase (MsrA/MsrB). Moreover, we provide evidence that the activity of σE is under control of NMB2145, directly downstream of rpoE. The protein encoded by NMB2145 is structurally related to anti-sigma domain (ASD) proteins and characterized by a zinc containing anti-σ factor (ZAS) motif, a hall mark of a specific class of Zn2+-binding ASD proteins acting as anti-σ factors. We demonstrate that Cys residues in ZAS, as well as the Cys residue on position 4, are essential for anti-σE activity of NMB2145, as found for a minority of members of the ZAS family that are predicted to act in the cytoplasm and responding to oxidative stimuli. However, exposure of cells to oxidative stimuli did not result in altered expression of σE. Conclusions Together, our results demonstrate that meningococci express a functional transcriptionally autoregulated σE factor, the activity of which is controlled by a novel meningococcal anti-σ factor belonging to the ZAS family.
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Affiliation(s)
- Carla Th P Hopman
- Academic Medical Center, Center for Infection and Immunity Amsterdam (CINIMA), Department of Medical Microbiology, Amsterdam, the Netherlands
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Crabbé A, Pycke B, Van Houdt R, Monsieurs P, Nickerson C, Leys N, Cornelis P. Response of Pseudomonas aeruginosa PAO1 to low shear modelled microgravity involves AlgU regulation. Environ Microbiol 2010; 12:1545-64. [PMID: 20236169 DOI: 10.1111/j.1462-2920.2010.02184.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
As a ubiquitous environmental organism that is occasionally part of the human flora, Pseudomonas aeruginosa could pose a health hazard for the immunocompromised astronauts during long-term missions. Therefore, insights into the behaviour of P. aeruginosa under spaceflight conditions were gained using two spaceflight-analogue culture systems: the rotating wall vessel (RWV) and the random position machine (RPM). Microarray analysis of P. aeruginosa PAO1 grown in the low shear modelled microgravity (LSMMG) environment of the RWV, compared with the normal gravity control (NG), revealed an apparent regulatory role for the alternative sigma factor AlgU (RpoE-like). Accordingly, P. aeruginosa cultured in LSMMG exhibited increased alginate production and upregulation of AlgU-controlled transcripts, including those encoding stress-related proteins. The LSMMG increased heat and oxidative stress resistance and caused a decrease in the oxygen transfer rate of the culture. This study also showed the involvement of the RNA-binding protein Hfq in the LSMMG response, consistent with its previously identified role in the Salmonella LSMMG and spaceflight response. The global transcriptional response of P. aeruginosa grown in the RPM was highly similar to that in NG. Fluid mixing was assessed in both systems and is believed to be a pivotal factor contributing to transcriptional differences between RWV- and RPM-grown P. aeruginosa. This study represents the first step towards the identification of virulence mechanisms of P. aeruginosa activated in response to spaceflight-analogue conditions, and could direct future research regarding the risk assessment and prevention of Pseudomonas infections during spaceflight and in immunocompromised patients.
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Affiliation(s)
- Aurélie Crabbé
- Laboratory of Microbial Interactions, Department of Molecular and Cellular Interactions, Flanders Institute for Biotechnology (VIB), Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium
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Mirpuri R, Jones W, Bryers JD. Toluene degradation kinetics for planktonic and biofilm-grown cells of Pseudomonas putida 54G. Biotechnol Bioeng 2009; 53:535-46. [PMID: 18634054 DOI: 10.1002/(sici)1097-0290(19970320)53:6<535::aid-bit1>3.0.co;2-n] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Toluene degradation kinetics by biofilm and planktonic cells of Pseudomonas putida 54G were compared in this study. Batch degradation of (14)C toluene was used to evaluate kinetic parameters for planktonic cells. The kinetic parameters determined for toluene degradation were: specific growth rate, micro(max) = 10.08 +/- 1.2/day; half-saturation constant, K(S) = 3.98 +/- 1.28 mg/L; substrate inhibition constant, K(I) = 42.78 +/- 3.87 mg/L. Biofilm cells, grown on ceramic rings in vapor phase bioreactors, were removed and suspended in batch cultures to calculate (14)C toluene degradation rates. Specific activities measured for planktonic and biofilm cells were similar based on toluene degrading cells and total biomass. Long-term toluene exposure reduced specific activities that were based on total biomass for both biofilm and planktonic cells. These results suggest that long-term toluene exposure caused a large portion of the biomass to become inactive, even though the biofilm was not substrate limited. Conversely, specific activities based on numbers of toluene-culturable cells were comparable for both biofilm and planktonically grown cultures. Planktonic cell kinetics are often used in bioreactor models to model substrate degradation and growth of bacteria in biofilms, a procedure we found to be appropriate for this organism. For superior bioreactor design, however, changes in cellular activity that occur during biofilm development should be investigated under conditions relevant to reactor operation before predictive models for bioreactor systems are developed.
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Affiliation(s)
- R Mirpuri
- Center for Biofilm Engineering, Montana State University, Bozeman, Montana 59717-3980, USA
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Martha B, Croisier D, Fanton A, Astruc K, Piroth L, Huet F, Chavanet P. Factors associated with mucoid transition of Pseudomonas aeruginosa in cystic fibrosis patients. Clin Microbiol Infect 2009; 16:617-23. [PMID: 20002106 DOI: 10.1111/j.1469-0691.2009.02786.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Although the mucoid form of Pseudomonas aeruginosa (Pa) is largely responsible for the progression of lung disease in cystic fibrosis (CF), the relationship between factors relating daily-care regimes to mucoidy acquisition are as yet poorly investigated. Fifty-two CF patients registered at the CF centre of Dijon, France, were retrospectively evaluated from the date of Pa colonization either to the first positive sputum culture for mucoid Pa (n = 26) or to the last culture in which the Pa remained non-mucoid (n = 26). All clinical, pathological and therapeutic events were recorded. The association between the parameters collected and mucoid transition of Pa was assessed in a Cox model with time-dependant covariables. The mean follow-up was 4.7 + or - 4.3 years. Three independent parameters were associated with the higher risk of mucoid transition of Pa: persistence of Pa in sputum (OR 7.89; p <0.01), use of inhaled bronchodilators (OR 3.40; p = 0.04), and the use of inhaled colimycin (OR 4.04; p = 0.02). Isolation of Staphylococcus aureus, Haemophilus influenzae or Streptococcus pneumoniae in sputum was associated with a lower risk (OR 0.24; p < 0.01). Mucoid transition of Pa was associated with variables that reflected the severity of both lung disease and Pa colonization. Although they do not lead to prophylactic measures, these results corroborate the need to avoid Pa persistence.
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Affiliation(s)
- B Martha
- Service des Maladies Infectieuses, Centre Hospitalier Universitaire, Dijon, France.
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Regulated intramembrane proteolysis in the control of extracytoplasmic function sigma factors. Res Microbiol 2009; 160:696-703. [DOI: 10.1016/j.resmic.2009.08.019] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2009] [Revised: 08/24/2009] [Accepted: 08/25/2009] [Indexed: 11/18/2022]
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Shi XY, Dumenyo CK, Hernandez-Martinez R, Azad H, Cooksey DA. Characterization of regulatory pathways in Xylella fastidiosa: genes and phenotypes controlled by gacA. Appl Environ Microbiol 2009; 75:2275-83. [PMID: 19218414 PMCID: PMC2675201 DOI: 10.1128/aem.01964-08] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2008] [Accepted: 02/03/2009] [Indexed: 11/20/2022] Open
Abstract
The xylem-limited, insect-transmitted bacterium Xylella fastidiosa causes Pierce's disease in grapes through cell aggregation and vascular clogging. GacA controls various physiological processes and pathogenicity factors in many gram-negative bacteria, including biofilm formation in Pseudomonas syringae pv. tomato DC3000. Cloned gacA of X. fastidiosa was found to restore the hypersensitive response and pathogenicity in gacA mutants of P. syringae pv. tomato DC3000 and Erwinia amylovora. A gacA mutant of X. fastidiosa (DAC1984) had significantly reduced abilities to adhere to a glass surface, form biofilm, and incite disease symptoms on grapevines, compared with the parent (A05). cDNA microarray analysis identified 7 genes that were positively regulated by GacA, including xadA and hsf, predicted to encode outer membrane adhesion proteins, and 20 negatively regulated genes, including gumC and an antibacterial polypeptide toxin gene, cvaC. These results suggest that GacA of X. fastidiosa regulates many factors, which contribute to attachment and biofilm formation, as well as some physiological processes that may enhance the adaptation and tolerance of X. fastidiosa to environmental stresses and the competition within the host xylem.
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Affiliation(s)
- Xiang Yang Shi
- Department of Plant Pathology and Microbiology, University of California, Riverside, California 92521, USA
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Pseudomonas aeruginosa AlgR controls cyanide production in an AlgZ-dependent manner. J Bacteriol 2009; 191:2993-3002. [PMID: 19270096 DOI: 10.1128/jb.01156-08] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen that causes chronic infections in individuals suffering from the genetic disorder cystic fibrosis. In P. aeruginosa, the transcriptional regulator AlgR controls a variety of virulence factors, including alginate production, twitching motility, biofilm formation, quorum sensing, and hydrogen cyanide (HCN) production. In this study, the regulation of HCN production was examined. Strains lacking AlgR or the putative AlgR sensor AlgZ produced significantly less HCN than did a nonmucoid isogenic parent. In contrast, algR and algZ mutants showed increased HCN production in an alginate-producing (mucoid) background. HCN production was optimal in a 5% O2 environment. In addition, cyanide production was elevated in bacteria grown on an agar surface compared to bacteria grown in planktonic culture. A conserved AlgR phosphorylation site (aspartate at amino acid position 54), which is required for surface-dependent twitching motility but not alginate production, was found to be critical for cyanide production. Nuclease protection mapping of the hcnA promoter identified a new transcriptional start site required for HCN production. A subset of clinical isolates that lack this start site produced small amounts of cyanide. Taken together, these data show that the P. aeruginosa hcnA promoter contains three transcriptional start sites and that HCN production is regulated by AlgZ and AlgR and is maximal under microaerobic conditions when the organism is surface attached.
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Cezairliyan BO, Sauer RT. Control of Pseudomonas aeruginosa AlgW protease cleavage of MucA by peptide signals and MucB. Mol Microbiol 2009; 72:368-79. [PMID: 19298369 DOI: 10.1111/j.1365-2958.2009.06654.x] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The ability of a pathogen to survive the defensive attacks of its host requires the detection of and response to perturbations in its own physiology. Activation of the extracytoplasmic stress response in the pathogen Pseudomonas aeruginosa results in higher tolerance against immune defences as well as in the production of alginate, a surface polysaccharide that also confers resistance to many host defences and antibiotic treatments. The alginate response is regulated by proteolytic cleavage of MucA, a transmembrane protein that inhibits the transcription factor AlgU, and by the periplasmic protein MucB. Here we show that specific peptides bind to the periplasmic AlgW protease and activate its cleavage of MucA. We demonstrate that tight binding of MucB to MucA strongly inhibits this cleavage. We also probe the roles of structural features of AlgW, including a key regulatory loop and its PDZ domain, in regulating substrate binding and cleavage.
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Affiliation(s)
- Brent O Cezairliyan
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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49
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50
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Schenk A, Weingart H, Ullrich MS. The alternative sigma factor AlgT, but not alginate synthesis, promotes in planta multiplication of Pseudomonas syringae pv. glycinea. MICROBIOLOGY (READING, ENGLAND) 2008; 154:413-421. [PMID: 18227245 DOI: 10.1099/mic.0.2007/012864-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2023]
Abstract
The phytopathogen Pseudomonas syringae pv. glycinea produces the exopolysaccharide (EPS) alginate, which is thought to function in epiphytic fitness and virulence. A key regulator for alginate biosynthesis in Pseudomonas aeruginosa and P. syringae is the alternative sigma factor AlgT (sigma(22)). In this study, the contribution of alginate synthesis and AlgT to in planta epiphytic fitness and virulence of P. syringae was examined. Alginate biosynthesis mutants were generated for the P. syringae pv. glycinea strains PG4180 and PG4180.muc, representing a comprehensive set of alginate- and AlgT-positive or -negative derivatives. Analysis of in vitro and in planta phenotypes revealed that AlgT strongly promoted in planta growth, survival and symptom development, but decreased the ability to grow in vitro. In contrast, alginate biosynthesis had only marginal impact. Quantitative in vitro and in planta gene expression analyses for alginate biosynthesis and algT were carried out at two temperatures in AlgT-negative and -positive backgrounds. algT as well as algD gene expression was AlgT-dependent, plant-inducible and temperature-dependent, with higher expression at 18 compared to 28 degrees C; however, no temperature dependence was observed in vitro. Our data suggest that AlgT may act as a global regulator for virulence and in planta fitness traits of P. syringae independent of its role in EPS biosynthesis.
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Affiliation(s)
- Alexander Schenk
- Jacobs University Bremen, School of Engineering and Sciences, Campus Ring 1, 28759 Bremen, Germany
| | - Helge Weingart
- Jacobs University Bremen, School of Engineering and Sciences, Campus Ring 1, 28759 Bremen, Germany
| | - Matthias S Ullrich
- Jacobs University Bremen, School of Engineering and Sciences, Campus Ring 1, 28759 Bremen, Germany
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