Fig 1.

Modulation of c-di-GMP levels and phosphodiesterase activity over the course of biofilm development by P. aeruginosa wild-type and dipA mutant strains. c-di-GMP levels (A) and specific phosphodiesterase activity (B) were determined using cell extracts obtained from P. aeruginosa PA14 planktonic, dispersed, and biofilm cells and biofilms remaining attached following dispersion (“biofilms post dispersion”). c-di-GMP/mg refers to c-di-GMP levels per total cell pellet protein (in mg). *, significantly different from biofilms (P < 0.05), as determined by ANOVA and SigmaStat. Experiments were repeated at least 5 times. Similarly, specific phosphodiesterase activity (B) was determined using cell extracts obtained from ΔdipA mutants grown planktonically and as a biofilm prior to and following addition of glutamate. **, significantly different based on Student's t test (P < 0.01). Experiments were repeated at least 4 times. (C) Domain overview of DipA and RbdA. GAF, cGMP-specific phosphodiesterases, adenylyl cyclases, and FhlA domain; PAS, Per Arnt Sim sensory domain; EAL, phosphodiesterase domain; GGDEF, diguanylate cyclase domain; aa, amino acid.