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Analysis of the quorum sensing circuitry of Burkholderia cenocepacia H111

Applicant Eberl Leo
Number 122013
Funding scheme Project funding (Div. I-III)
Research institution Institut für Pflanzen- und Mikrobiologie Universität Zürich
Institution of higher education University of Zurich - ZH
Main discipline Experimental Microbiology
Start/End 01.05.2009 - 31.12.2012
Approved amount 538'735.00
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All Disciplines (2)

Discipline
Experimental Microbiology
Molecular Biology

Keywords (6)

Quorum sensing; Burkholderia cepacia; Biofilm; Caenorhabditis elegans; non-mammalian pathogenesis models; Galleria mellonella

Lay Summary (English)

Lead
Lay summary
Taxonomic studies have shown that Burkholderia cenocepacia is a member of the Burkholderia cepacia complex (Bcc), a group of at least 17 distinct, but closely related species. Strains of the Bcc are ubiquitously distributed in nature and have been isolated from soil, water, the rhizosphere of plants, industrial settings, hospital environments, and from infected humans. Bcc strains have an enormous biotechnological potential and have been used for bioremediation of recalcitrant xenobiotics, plant growth promotion, and biocontrol purposes. At the same time, however, Bcc strains have emerged as problematic opportunistic pathogens in both, cystic fibrosis patients, chronic granulomatous disease and nosocomial outbreaks. The inherent pathogenic potential of biotechnologically interesting strains is preventive of their wide-spread application. Like many Gram-negative bacteria, Bcc strains employ cell-to-cell communication ("quorum sensing"; QS) systems to express various functions in a population density-dependent manner. Previous work has demonstrated that the production of proteases, chitinases, and siderophores, motility, biofilm formation and virulence is QS-regulated in Bcc strains. This project aims at identifying those QS-dependent functions that are important for biofilm formation and pathogenicity. The specific aims are:o To define the QS regulon of B. cenocepacia H111 by the aid of a combined transcriptomic and proteomic approacho To identify regulators affecting the CepIR signaling systemo To identify QS-regulated genes required for biofilm formation and to determine their role in biofilm developmento To identify QS-regulated virulence factors and to assess their importance in different infection modelsTo address these questions we will employ classic genetic methods in combination with transcriptomics, proteomics as well as wit transcriptome and proteome data with phenotypic microarrays. Biofilms will be cultivated in artificial flow chambers and virulence of strains will be assayed in two non-mammalian infection models, using the nematode Caenorhabditis elegans and the larvae of the greater wax moth Galleria mellonella. The proposed work program aims at the identification of global regulators affecting QS and QS-regulated factors required for biofilm formation and pathogenicity. This line of research may therefore also lead to the identification of novel targets for the development of antibacterial drugs. Furthermore, knowledge of the virulence factors of Burkholderia is a crucial prerequisite for the assessment of the potential risks associated with strains showing promise in biotechnological applications.
Direct link to Lay Summary Last update: 21.02.2013

Responsible applicant and co-applicants

Employees

Publications

Publication
Identification of Burkholderia cenocepacia Strain H111 Virulence Factors Using Nonmammalian Infection Hosts.
Schwager Stephan, Agnoli Kirsty, Köthe Manuela, Feldmann Friederike, Givskov Michael, Carlier Aurelien, Eberl Leo (2013), Identification of Burkholderia cenocepacia Strain H111 Virulence Factors Using Nonmammalian Infection Hosts., in Infection and Immunity, 81(1), 143-53.
Dynamics of AHL mediated quorum sensing under flow and non-flow conditions
Meyer A, Megerle JA, Kuttler C, Muller J, Aguilar C, Eberl L, Hense BA, Radler JO (2012), Dynamics of AHL mediated quorum sensing under flow and non-flow conditions, in PHYSICAL BIOLOGY, 9(2), 1-10.
Exposing the third chromosome of Burkholderia cepacia complex strains as a virulence plasmid
Agnoli K, Schwager S, Uehlinger S, Vergunst A, Viteri DF, Nguyen DT, Sokol PA, Carlier A, Eberl L (2012), Exposing the third chromosome of Burkholderia cepacia complex strains as a virulence plasmid, in MOLECULAR MICROBIOLOGY, 83(2), 362-378.
Identification of functions linking quorum sensing with biofilm formation in Burkholderia cenocepacia H111.
Inhülsen Silja, Aguilar Claudio, Schmid Nadine, Suppiger Angela, Riedel Kathrin, Eberl Leo (2012), Identification of functions linking quorum sensing with biofilm formation in Burkholderia cenocepacia H111., in MicrobiologyOpen, 1(2), 225-42.
The genetic basis of cadmium resistance of Burkholderia cenocepacia
Schwager S, Lumjiaktase P, Stockli M, Weisskopf L, Eberl L (2012), The genetic basis of cadmium resistance of Burkholderia cenocepacia, in ENVIRONMENTAL MICROBIOLOGY REPORTS, 4(5), 562-568.
A Burkholderia cenocepacia orphan LuxR homolog is involved in quorum-sensing regulation.
Malott Rebecca J, O'Grady Eoin P, Toller Jessica, Inhülsen Silja, Eberl Leo, Sokol Pamela A (2010), A Burkholderia cenocepacia orphan LuxR homolog is involved in quorum-sensing regulation., in Journal of bacteriology, 191(8), 2447-60.
Identification of specific and universal virulence factors in Burkholderia cenocepacia strains by using multiple infection hosts.
Uehlinger Susanne, Schwager Stephan, Bernier Steve P, Riedel Kathrin, Nguyen David T, Sokol Pamela A, Eberl Leo (2009), Identification of specific and universal virulence factors in Burkholderia cenocepacia strains by using multiple infection hosts., in Infection and immunity, 77(9), 4102-10.

Collaboration

Group / person Country
Types of collaboration
M. Aebi, ETH Zürich Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Exchange of personnel
Lian-Hui Zhang,Institute of Molecular and Cell Biology, A*STAR Singapore Singapore (Asia)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
P. A. Sokol, Faculty of Medicine, University of Calgary Canada (North America)
- in-depth/constructive exchanges on approaches, methods or results
- Publication

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
ISME14 (14th international symposium on microbial ecology) Talk given at a conference Quorum sensing triggers asocial behavior in the early phase of biofilm development of Pseudomonas putida IsoF 24.08.2012 Copenhagen, Denmark, Denmark Eberl Leo;
35th European Cystic Fibrosis Conference Talk given at a conference Animal Models for Drug Development 07.06.2012 Dublin, Ireland, Ireland Eberl Leo;
The British Society of Plant Pathology, University of Cambridge Talk given at a conference Bacterial cell-to-cell communication in the rhizosphere 16.12.2011 Cambridge, UK, Great Britain and Northern Ireland Eberl Leo;
4th FEMS Congress of European Microbiologists Talk given at a conference Cell-to-cell communication in members of the genus Burkholderia: a regulatory system that controls the production of various biotechnologically valuable secondary metabolites 30.06.2011 Geneva, Switzerland, Switzerland Eberl Leo;
Biolloquium der TU München Individual talk Cell-to-cell communication in Burkholderia: Friends and foes speaking the same language 14.12.2010 Freising, Germany, Germany Eberl Leo;
ÖGMBT annual meeting Talk given at a conference Cell-to-cell communication in Burkholderia: Friends and foes speaking the same language”. ÖGMBT annual meeting 29.09.2010 Vienna, Austria, Austria Eberl Leo;
Jahrestagung der Vereinigung für Allgemeine und Angewandte Mikrobiologie (VAAM) Talk given at a conference The role of quQorum sensing in the pathogenesis of Burkholderia cenocepacia in multiple infection hosts 29.03.2010 Hannover, Germany, Germany Eberl Leo;
34th FEBS Congress Talk given at a conference Biofilm formation of members of the genus Burkholderia is dependent on cell-to-cell communication 08.07.2009 Prague, Czech Republic, Czech Republic Eberl Leo;


Awards

Title Year
FEBS National Lecturer 2010

Associated projects

Number Title Start Funding scheme
143773 Analysis of the quorum sensing circuitry of Burkholderia cenocepacia H111: The role of the Burkholderia diffusible signal factor (BDSF) 01.01.2013 Project funding (Div. I-III)
104215 Investigations on the role of quorum sensing for biofilm formation, plant colonization and biocontrol activity in Burkholderia cepacia complex strains 01.04.2004 Project funding (Div. I-III)

Abstract

Polyphasic taxonomic studies have shown that Burkholderia cenocepacia is a member of the Burkholderia cepacia complex (Bcc), a group of nine distinct, but closely related species. Strains of the Bcc are ubiquitously distributed in nature and have been isolated from soil, water, the rhizosphere of plants, industrial settings, hospital environments, and from infected humans. Bcc strains have an enormous biotechnological potential and have been used for bioremediation of recalcitrant xenobiotics, plant growth promotion, and biocontrol purposes. At the same time, however, Bcc strains have emerged as problematic opportunistic pathogens in both, cystic fibrosis patients, chronic granulomatous disease and nosocomial outbreaks. The inherent pathogenic potential of biotechnologically interesting strains is preventive of their wide-spread application. Like many Gram-negative bacteria, Bcc strains employ cell-to-cell communication (“quorum sensing”; QS) systems to express various functions in a population density-dependent manner. Previous work has demonstrated that the production of extracellular proteases, chitinases, and siderophores, swarming motility, biofilm formation and expression of pathogenic traits is QS-regulated in the large majority of Bcc strains. The present proposal aims at characterizing the QS circuitry in B. cenocepacia H111 in better detail and at identifying those QS-regulated functions that are important for biofilm formation and pathogenicity. The specific aims are:1) To define the QS regulon of B. cenocepacia H111 by the aid of a combined transcriptomic and proteomic approach2) To identify regulators affecting the CepIR signaling system3) To identify QS-regulated genes required for biofilm formation and to determine their role in biofilm development4) To identify QS-regulated virulence factors and to assess their importance in different infection modelsTo address these questions we will employ a combination of classic genetic methods and functional genomics (transcriptomics and proteomics), as not only the genome sequences of five B. cenocepacia strains but also a Burkholderia gene array has become available. We will also use phenotypic microarrays to identify novel QS regulated functions and to link the transcriptome and proteome data with phenotypic traits. Biofilms will be cultivated in artificial flow chambers and virulence of strains will be assayed in two non-mammalian infection models, using the nematode Caenorhabditis elegans and the larvae of the greater wax moth Galleria mellonella. For the visualization of cells in biofilms and during infection we will employ strains marked with different fluorescent proteins in combination with confocal laser scanning microscopy.The proposed work program aims at the identification of both global regulators affecting QS and QS-regulated factors required for biofilm formation and pathogenicity. This line of research may therefore also lead to the identification of novel targets for the development of antibacterial drugs. Furthermore, knowledge of the virulence factors of Burkholderia is a crucial prerequisite for the assessment of the potential risks associated with strains showing promise in biotechnological applications.
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