Comparative Proteomic Analysis of Differentially Expressed Proteins in the Earthworm Eisenia fetida during Escherichia coli O157 H7 Stress

Escherichia coli O157 H7 is an intestine-inhabiting bacterium associated with many severe disease outbreaks worldwide It may enter the soil environment with the excreta of infected animals (e g, horses, cattle, chickens) and humans Earthworms can protect themselves against invading pathogens because of their efficient innate defense system Identification of differential proteomic responses to E coli 0157 H7 may provide a better understanding of the survival mechanisms of the earthworm Eisenia fetida that lives in E coli O157 H7-polluted environments Whole earthworm extracts collected at days 7 14, 21, and 28 after E coli O157 H7 stress were analyzed by two-dimensional gel electrophoresis and quantitative image analysis In total 124 proteins demonstrated significant regulation at least at one time point, and 52 proteins were identified by matrix-assisted laser desorption/ionization tandem time-of-flight mass spectrometry and database searching Compared with control samples, 11 protein spots were up-regulated and 41 were down-regulated for at least one time point The identified proteins, including heat shock protein 90, fibrinolytic protease 0, gelsolin-like protein, lombricine kinase, coelomic cytolytic factor-1, manganous superoxide dismutase catalase, triosephosphate isomerase, extracellular globin-4, lysenin, intermediate filament protein, and glyceraldehyde-3-phosphate dehydrogenase are involved in several processes, including transcription, translation, the tricarboxylic acid cycle, and the glucose metabolic process Thus our study provides a functional profile of the E coli O157 H7-responsive proteins in earthworms We suggest that the variable levels and trends in these spots on the gel may be useful as biomarker profiles to investigate E coli O157 H7 contamination levels in soils