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Journal of Biomedicine and Biotechnology
Volume 2012, Article ID 408690, 9 pages
Research Article

Proteomic Profiling of the Dioxin-Degrading Bacterium Sphingomonas wittichii RW1

1Retrovirus Laboratory, Department of Molecular and Comparative Pathobiology, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
2Center for Environmental Security, Biodesign Institute, Arizona State University, Tempe, AZ 85287-5904, USA
3Security and Defense Systems Initiative, Arizona State University, Tempe, AZ 85287-5904, USA
4Department of Environmental Health Sciences, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA

Received 10 May 2012; Revised 29 July 2012; Accepted 30 July 2012

Academic Editor: Andre Van Wijnen

Copyright © 2012 David R. Colquhoun et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Sphingomonas wittichii RW1 is a bacterium of interest due to its ability to degrade polychlorinated dioxins, which represent priority pollutants in the USA and worldwide. Although its genome has been fully sequenced, many questions exist regarding changes in protein expression of S. wittichii RW1 in response to dioxin metabolism. We used difference gel electrophoresis (DIGE) and matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) to identify proteomic changes induced by growth on dibenzofuran, a surrogate for dioxin, as compared to acetate. Approximately 10% of the entire putative proteome of RW1 could be observed. Several components of the dioxin and dibenzofuran degradation pathway were shown to be upregulated, thereby highlighting the utility of using proteomic analyses for studying bioremediation agents. This is the first global protein analysis of a microorganism capable of utilizing the carbon backbone of both polychlorinated dioxins and dibenzofurans as the sole source for carbon and energy.