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