FIG. 1.

Expression patterns of E. coli W3110 proteins at various growth phases. (A) An early-stationary-phase culture of E. coli W3110 (A type) in LB medium at 37°C was diluted 170-fold with fresh LB medium, and the shaking culture was continued at 37°C. The total number of cells per milliliter (solid circles) and the average volume of cells (open squares) were measured with a Coulter Multisizer II. The protein concentration of cell lysates (open circles) was determined by staining with a Bio-Rad protein assay kit. (B) The same E. coli W3110 (A type) culture for the indicated times was stained with DAPI and observed for cell morphology. The bar in the 2.3-h sample represents 1 μm. (C) At the indicated time points (above the lane markers), aliquots of the culture were removed for the preparation of cell lysates. Portions of the cell lysates containing 15 μg of total proteins were subjected to SDS–15% PAGE. Gels were stained with Coomassie brilliant blue. The molecular mass markers (M, standard markers; PM, prestained markers) used were as follows: phosphorylase b, 97.4 kDa; bovine serum albumin, 66.2 kDa; ovalbumin, 45.0 kDa; carbonic anhydrase, 31.0 kDa; soybean trypsin inhibitor, 21.5 kDa; and lysozyme, 14.4 kDa.