Martin Luther University Halle-Wittenberg

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Dr. Cornelia Große

Regulatory networks controlling heavy metal homeostasis

We focus on the heavy metal homeostasis of Cupriavidus metallidurans CH34 and Escherichia coli by large scale genomic analysis using DNA microarray technology. This technique allows to highlight differences in gene expression between cells originate from different environmental conditions. The aim is the identification of changes in the transcriptom of bacterial cells under influence of different heavy metals, like Co, Zn and Cd.

Sigma factors of the extracytoplasmic function family are part of the bacterial stress response and essential for the regulation of transcription initiation. They react to stress signals outside the cytoplasmic membrane by transcriptional activation of genes encoding products involved in defense or repair processes. Cupriavidus metallidurans strain CH34 is a highly metal resistant bacterium that contains 11 sigma factors of the ECF protein family, which can be subgrouped into four different clusters. One cluster is marked as the primary ECF sigma factor for siderophore-mediated iron uptake. We study the function of the sigmafactors of the other ECF-clusters and it´s regulons.


F. Reith, B. Etschmann, C. Große, H. Moors, M.A. Benotmane, P. Monsieurs, G. Grass, C. Doonan, S. Voigt, B. Lai, G. Martinez-Criado, G.N. George, D.H. Nies, M. Mergeay, A. Pring, G. Southam, J. Brugger. 2009. Mechanisms of gold biomineralization in the bacterium Cupriavidus metallidurans. PNAS. 106(42): 17757-17762.

S.H. Auda, Y. Mrestani, C. Große, D.H. Nies, R.H.H. Neubert. 2009. Preparation, physicochemical characterization and biological evaluation of cefodizime metal ion complexes. J. Phar. Pharm. 61(6): 753-8.

K. Helbig, C. Große, D.H. Nies. 2008. (contributed equally) Cadmium toxicity in glutathione mutants of Escherichia coli. J. Bacteriol. 190:5439-54.

C. Große, S. Friedrich, D.H. Nies. 2007. Contribution of extracytoplasmic function sigma factors to transition metal homeostasis in Cupriavidus metallidurans strain CH34. J. Mol. Microbiol. Biotechnol. 12:227-240.

C. Große, J. Scherer, D. Koch, M. Otto, N. Taudte, G. Grass. 2006. A new ferrous iron-uptake transporter, EfeU (YcdN), from Escherichia coli. Mol. Microbiol. 62(1):120-31.

D.H. Nies, G. Rehbein, T. Hoffmann, C. Baumann, C. Große. 2006. Paralogs of genes encoding metal resistance proteins in Cupriavidus metallidurans strain CH34. J. Mol. Micobiol. Biotechnol. 11:82-93.

C. Bleuel, C. Große, N. Taudte, J. Scherer, D. Wesenberg, G.J. Krauß, D.H. Nies, G. Grass. 2005. (contributed equally)TolC is involved in enterobactin efflux across the outer membrane of Escherichia coli. J. Bacteriol. 187:6701-6707.

M. Egler, C. Große, G. Grass, D.H. Nies. 2005. (contributed equally) Role of the extracytoplasmic function protein family sigma factor RpoE in metal resistance of Escherichia coli. J. Bacteriol. 187(7): 2297- 2307.

C. Große
, A. Anton, T. Hoffmann, S. Franke, G. Schleuder, D.H. Nies. 2004. Identification of a regulatory pathway that controls the heavy-metal resistance system Czc via promotor czcNp in Ralstonia metallidurans. Arch. Microbiol. 182 (2-3):109-18.