FIGURE 4.

Exogenous ammonia inhibits the transformation from glycine to 5,10-methylene-THF. (A) Expression of gcvP1 and gcvP2 by the w.t. in a co-culture with 10% LasR mutants. Hollow bars indicate PM-casein without ammonium sulfate and black bars indicate PM-casein with ammonium sulfate. proC was used as a housekeeping gene. (B) PAO1 generates ammonia faster in the absence of ammonium sulfate (hollow circles) than in its presence (black circles). (C) Model of the flux between exogenous ammonia and cyanide production in P. aeruginosa. In panel C, red stars indicate ROS. The red NH₄⁺ indicates exogenous ammonia in media, and black text indicates released ammonia by metabolism. Experiments were performed in triplicate. ^∗ indicates p < 0.05 by paired Student’s t-test (panel A) or one-way ANOVA (panel B).