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United States Department of Agriculture

Agricultural Research Service

Research Project: MOLECULAR CHARACTERIZATION OF PATHOGENS AND THEIR RESPONSES TO ENVIRONMENTAL FACTORS Title: Comparative Proteomic Approaches to Understanding the Responses of Food-borne Pathogens to Environmental Factors

Author
item Gunther, Nereus

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: October 12, 2006
Publication Date: N/A

Technical Abstract: An understanding of how food-borne bacterial pathogens respond to environmental stress conditions enhances the ability to control these pathogens. A popular method for understanding bacterial stress responses is through the measurement of global gene expression under various growth conditions, commonly referred to as a genomic approach. More recently methods that measure the relative protein amounts produced by bacteria under different growth conditions have gained in popularity. These are referred to as proteomic methods and have an advantage over genomic methods because the end-products of bacterial responses are measured directly, and therefore, there is less risk of being misled by post-translational events that can occur after initial gene expression. A commonly used method for performing bacterial proteomic research is two-dimensional (2D) gel electrophoresis. However, in recent years, a new procedure for protein separation was introduced, which utilizes column-based liquid chromatography separation. We utilized both of these proteomic techniques to compare the proteomes of Escherichia coli O157:H7 strain EDL933 against a variant containing a point mutation in the promoter region of the csgD transcriptional regulator. The variant strain produces curli fibers and forms significantly thicker biofilms as compared to the parent strain. A number of differences in protein expression were observed to occur between the two strains. Many of the proteins observed to be differentially expressed between the two organisms were known stress response genes, as well as purely hypothetical genes. In addition, certain advantages and disadvantages were identified for each of the two proteomic separation techniques, specifically in the areas of cost, system maintenance, sample identification, and reproducibility. In addition the advantages/disadvantages of these comparative proteomic techniques are considered alongside genomic techniques also used to determine bacterial expression profiles. Finally a procedure is suggested to integrate each of these techniques, both proteomic and genomic, to create a more complete and reliable comparison of bacterial expression.

Last Modified: 11/23/2014
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