Protein patterns of gel-entrapped Escherichia coli cells differ from those of free-floating organisms

The two‐dimensional electrophoretic patterns of cellular proteins from gel‐entrapped Escherichia coli cells were compared to those of exponential‐ and stationary‐phase free‐floating organisms. The amounts of several proteins in immobilized cells were significantly different from those in free bacteria. Immobilized organisms rapidly produced a high level of dipeptide permease and a single‐strand binding protein, and progressively accumulated an aldehyde dehydrogenase. Immobilization also induced a decrease in the levels of two proteins, i.e., the YFID protein and a DNA‐binding, stationary‐phase protein. The possible role of these proteins in the high resistance of immobilized bacteria to stresses is discussed.