FIG 4.

Roles of CdaA and CdaR in c-di-AMP biosynthesis, as demonstrated by intracellular c-di-AMP levels in the wild-type (wt) strain EGD-e and in strains LMJR46 (IcdaA), LMJR45 (ΔcdaR), BPL16 (IcdaR), and LMJR65 (ΔcdaR IcdaA). All strains were grown in BHI broth at 37°C to an optical density of 1.0. For depletion of CdaA and CdaR, the strains LMJR46 (IcdaA), LMJR65 (ΔcdaR IcdaA), and BPL16 (IcdaR) were pregrown overnight in the presence of 1 mM IPTG. The precultures were washed and used to start a depletion culture without IPTG, and the cultures were supplemented with 1 mM inducer. Data from three biological replicates are shown; standard deviations are indicated as error bars. *, P < 0.05, and **, P < 0.005, significant changes detected using unpaired t tests.