FIG 5.

PspA is a negative regulator of the Psp response, and PspB, -C, and -F are positive regulators. Cultures were grown to mid-log phase (4 h). β-Galactosidase activity was produced from a chromosomal promoter fusion of lacZΩPpspA. (A) Loss of pspA leads to a large increase in PpspA activity, which can be reduced by complementation. (B) Loss of pspB, pspC, or pspF results in the inability to induce the Psp response. ***, P < 0.001 by Student’s t test. Error bars represent ± standard deviations.