Project: Investigating the effect of substrate upon the expression of proteins in the dioxin-degrading bacterium Sphingomonas wittichii strain RW1

Investigators: David R. Colquhoun, Ph.D. Cand. and Dr. Rolf U. Halden, Ph.D., P.E.

Collaborators: Dr. Robert Cole, Ph.D.

This study aims to harness the information contained within the RW1 genome to study the effects of growth substrate upon protein expression. In order to do this, 2 proteomes harvested from biomass grown on two different growth media are separately labeled, and then pooled and separated by 2-dimensional gel electrophoresis. Quantification is completed using DIGE technology, and proteins are identified using post-electrophoresis mass spectrometry techniques. The aims of this project are to (i) identify catabolic microbial biomarkers of degradation, and (ii) elucidate the mechanistic proteomic changes involved in pollutant degradation.

Figure 1. Proteome fraction separated by 2-dimensional electrophoresis. Bacteria were grown on two substrates and labeled with (A) Cy dyes and (B) post stained using standard silver staining techniques.

Mass spectrometry techniques are currently being utilized to identify proteins involved in the degradation of pollutants; to date we have identified several potential biomarkers of degradation. For further information, please refer to:

Halden, R. U., D. R. Colquhoun, and E. S. Wisniewski. 2005. Identification and phenotypic characterization of Sphingomonas wittichii strain RW1 by peptide mass fingerprinting using matrix-assisted laser desorption ionization-time of flight mass spectrometry. Appl Environ Microbiol 71:2442-51.