Submitted to: Journal of Proteomic Research American Chemical Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/13/2008
Publication Date: 1/20/2009
Citation: Lippolis, J.D., Bayles, D.O., Reinhardt, T.A. 2009. Proteomic changes in Escherichia coli when grown in fresh milk versus laboratory media. Journal of Proteome Research. 8(1):149-158.
Interpretive Summary: Infection of the udder (mastitis) is a major economic problem for the dairy industry. In the dairy industry, this disease alone accounts for $2 billion a year in losses to the industry. Bacteria, such as Escherichia coli (E. coli) are the major cause of mastitis in dairy cows. Milk is the environment that bacteria must be grown in to establish an infection of the mammary gland. However, milk is not a rich growth media for bacteria. In fact, milk naturally contains many mechanisms to inhibit bacterial growth. Our goal was to determine the changes in protein expression when E. coli was grown in milk using proteomics. Proteomics is the identification of proteins made in a cell. Previous protein identification techniques did so one at a time, where proteomics can identify hundreds of proteins in a sample. We have identified 1,000 proteins in E. coli, of which hundreds show changes in their expression levels when the bacteria was grown in milk. The next stage of this research will focus on the proteins that changed and whether these changes enable bacteria grown in the mammary gland. This information will help us better understand bacteria infections and may lead to new antibiotic strategies and fight mastitis in the dairy industry.
Technical Abstract: In order to establish an infection, bacteria must first adapt to the host environment and grow. For mastitis, the media in which bacteria must adapt to is milk. Growth of a mammary pathogenic Escherichia coli in milk results in the up and down regulation of hundreds of proteins, some of which may be important to the pathogenesis of this organism.