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Comprehensive gene deletion study to identify cell wall organisation and structure in Candida glabrata

 
: Stevens, R.; Hiller, E.; Dörflinger, M.; Gabaldon, T.; Schwarzmüller, T.; Kuchler, K.; Rupp, S.

Federation of European Biochemical Societies -FEBS-, Copenhagen; Federation of European Microbiological Societies -FEMS-:
3rd FEBS advanced lecture course Human Fungal Pathogens (HFP). Molecular mechanisms of host-pathogen interactions and virulence. Abstract book : May 2-8, 2009 La Colle sur Loup, France
La Colle sur Loup, 2009
pp.174
FEBS advanced lecture course Human Fungal Pathogens (HFP) <3, 2009, La Colle sur Loup>
English
Abstract
Fraunhofer IGB ()

Abstract
Although Candida glabrata has become the second most important pathogenic Candida
species, only few of its virulence mechanisms have been identified so far.
To get a more comprehensive idea of the virulence mechanisms of C. glabrata, we use
comprehensive gene deletion studies in order to elucidate the organisation and components of
its cell wall. These studies are undertaken within an ERA-Net consortium, FunPath. Genes
coding for putative proteins of the cell wall, known signalling pathways, membrane-bound
receptors, transporters and transcription factors were identified by comparative genome
analysis and subsequently deleted (about 500 deletion mutants at present). This library is
screened with biological assays for strains with altered cell wall stability, stress tolerance, or
adhesion.
Up to now, several strains were found in survival assays on plates to be more sensitive to
congo red, osmotic stress or increased temperature. The genes deleted in these mutants were
homologues to Saccharomyces cerevisiae genes that are involved in cell wall integrity and the
MapK-pathways.
The ability to adhere on a surface is tested by a series of tests with increasing complexity and
approximation to the host environment. To get a first hint of the adherence ability of the
mutants we analysed their adhesion on solid agar plates using wash tests. The genes we
identified to be important for adherence under these conditions were associated to the cell wall
or involved in cytokinesis. To verify our screening results we will investigate the adhesion and
invasion behaviour of the interesting mutant strains in in vitro experiments with a human
epithelial model. In addition to the screening we plan to analyse the adhesion ability of all
mutant strains in a comparative approach with pools of mutants on epithelial models. All
deletion strains are tagged with a specific barcode sequence that can be detected via an inhouse
barcode microarray. Experiments with in vivo models will be carried out by our project
partners (FunPath). Using genome wide transcription profiles, it will be possible, for instance,
to further characterize strains with reduced virulence. The results generated will allow
conclusions about basic pathogenicity mechanisms and possible targets for the therapy of
fungal infections.

: http://publica.fraunhofer.de/documents/N-154078.html