Changes in protein composition and hydrolytic enzyme activity of Escherichia coli and Hafnia alvei grown in human fluids

Growing of Escherichia coli and Hafnia alvei cells in several cell-free human fluids, such as normal serum, serum from diabetic patients, pleural, ascitic and spinal fluid, revealed that various biochemical changes occurred. Protein profile on SDS-PAGE as well as acid and alkaline phosphohydrolytic enzymes on native gels of cell extracts were affected after culturing of bacteria in the above fluids. Gelatinolytic and hyaluronolytic activity was of interest because both of them are histolytic enzymes. Although there was a potential appearance of gelatinolytic bands on gelatin-SDS-PAGE in cells starved in seawater, none of these activities were expressed in cells grown in human fluids. A hyaluronolytic activity of approximately 45 KDa was present in cells cultured in Mueller Hinton broth. This enzyme was decreased either in cells starved in seawater or in cells grown in human fluids to an almost invisible band on hyaluronan-SDS-PAGE.