Protein patterns of gel-entrapped Escherichia coli cells differ from thoseof 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 bacter ia. Immobilized organisms rapidly produced a high level of dipeptide permea se and a single-strand binding protein, and progressively accumulated an al dehyde 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 imm obilized bacteria to stresses is discussed.