Profile of expressed proteins of γ-irradiated foodborne pathogen Escherichia coli O157:H7 analysed by capillary electrophoresis

Abstract

The aim of this study was to evaluate the effects of gamma irradiation treatment at different doses on expressed proteins in Escherichia coli (E. coli) O157:H7. Bacterial samples were gamma irradiated at doses of 0.4 and 1.3 kGy to create damaged cells and to kill cells, respectively. The bacterial proteins were extracted and analyzed using a ProteomeLab sodium dodecyl sulfate gel molecular weight (MW) analysis kit and performed on a capillary electrophoresis system (ProteomeLab™ PA 800). The major peaks were calculated and expressed as equivalent MW and corrected peak areas. One protein named as bacteriophage N4 adsorption protein B with a MW of 85.2 kilodalton (kDa) was determined and its expression level was not significantly changed (p ≥ 0.05) at different doses of irradiation treatment. Seven proteins consisting of rhamnulokinase, glycerol kinase, hypothetical protein Z2695, preprotein translocase subunit SecD, DNA polymerase III subunits gamma and tau, choline transport protein-BetT and primosome assembly protein-PriA with the respective MW of 54.0, 56.8, 60.7, 66.5, 71.0, 75.7 and 81.5 kDa were statistically changed in their expressed level (p < 0.05) at different doses of irradiation treatment. The changes in expressed level of proteins could be related to the sensitivity or resistance of E. coli to gamma irradiation treatment.

Keywords: Capillary electrophoresis, Escherichia coli O157:H7, protein expression, gamma irradiation.