FIG 5.

Acetaldehyde is an inducer of PA4022::lacZ and eat::lacZ in P. aeruginosa PAO1. (A) PA4022::lacZ and eat::lacZ were constructed by fusing the 5′-regulatory regions of each of these genes with lacZ. Fusions were individually cloned into a promoter-less plasmid ΔPlac-pBBR1MCS-5. (B) Expression of PA4022::lacZ increased with the addition of ethanolamine, acetaldehyde, acetoin, ethanol, or hydrazone. (C) Expression of eat::lacZ increased with the addition of ethanolamine, acetaldehyde or hydrazone. (D) Expression of the exaC::lacZ fusion did not significantly change with the addition of any substrate. P. aeruginosa PAO1 carrying the LacZ fusions was grown in acetate-minimal medium to an OD₆₀₀ of 0.3 and then challenged with a 2.0 mM concentration of the indicated substrate. LacZ activities were measured 90 min postaddition of substrate. Significant differences in LacZ activities were determined using an ANOVA with Dunnett's post hoc test (α-value, 0.05) and are indicated with asterisks. Data points represent mean values (n = 3) ± SD.