FIG. 3.

Kinetics of permanent attachment. A series of coverslips were incubated for 4 h with MG1655 (A) or its isogenic csrA mutant, TR1-5 (B), and slides were assembled and inverted, as described in Fig. 2. Individual slides were inverted a second time at intervals of 20 to 60 min thereafter, as indicated, and the densities of bacterial cells attached to the upper surfaces of the slides were monitored over time. This allowed both the number of cells and the proportion of permanently attached cells to be determined at each time interval. (C) The proportion of permanently attached cells from panels A and B were plotted against the time that was permitted for the gravity-displaced cells to reattach. Cell density values were determined as in Fig. 2.