Fig. 2. CfaD slows the proliferation of cells growing in liquid shaking culture. (A) Cells were diluted to 2x10⁵ cells/ml in HL5 and the cell density was measured daily. Values are the mean ± s.e.m. from six independent experiments. The absence of error bars indicates that the error was smaller than the plot symbol. WT, wild-type. At day 9, all of the cfaD^– cells appeared to be dead. The saturation densities (in units of 10⁷ cells/ml) were 2.4±0.1 for wild type, 3.6±0.3 for cfaD^–, 1.5±0.1 for cfaD^OE, and 2.2±0.1 for cfaD^–/cfaD^OE. The differences between all values are significant (P<0.05) except WT versus cfaD^–/cfaD^OE, which was not significant (1-way ANOVA, Tukey's test). (B) The data from the first 3 days were plotted using a log scale for the density. (C) Proliferation of cells growing on a lawn of bacteria was measured by plating 10³ cells on bacteria and counting the number of cells at the indicated times. Values are the mean ± s.e.m. from three independent experiments.