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<OL> <LI> Determine the cellular sensors responsible for induction of bacterial responses to stress; <LI> Determine the practical significance of bacterial adaptation to protection from stress; <LI> identify molecular markers expressed as a result of stress and develop methods for detection of stressed/injured pathogens in foods; <LI> Determine the mechanism of acquisition of antimicrobial resistance genes in pathogens.
Determine how environments affect transcription and translation of stress and virulence proteins, by changes in protein synthesis using 35S-methionine labeling, 2-D gel electrophoresis and autoradiography. Cold, acid and drying-induced cross-protection against other stresses will be investigated. Immunocompromised mice will be used for virulence assessment. Wild-type and mutant strains will be used to determine genetics of global stress responses. Ribosome disruption for the molecular induction of cold shock will be studied. <P> Thermosensitivity induced by cold shock will be evaluated for use in ready-to-eat foods. E. coli 0157:H7 curli protein will be investigated to show how environment affects attach- ment to meats. Improved detection methods will be developed using pulsed field gel electrophoresis, subtractive hybridization, and reverse transcriptase PCR. Genetic relatedness of various E. coli serotypes will be evaluated in terms of stress response genes, virulence factors and virulence.