Fitness Landscape of Antibiotic Tolerance in Pseudomonas aeruginosa Biofilms
Figure 5
Characterization of loci conferring biofilm-specific tobramycin tolerance.
(A) The MPAO1 strain with either an empty vector or a plasmid containing PA0614 under the control of an arabinose-inducible promoter was grown in M63 medium in the presence and absence of 0.2% arabinose (Ara). (B) A gfp promoter fusion was used to measure the expression of PA0614 in both biofilm and planktonic settings, in the presence and absence of 8 µg/ml tobramycin. Promoter activities are normalized by colony forming units (CFU). (C) Expression differences between exponentially growing cultures of wild-type and PA3726 mutant cells were sorted and partitioned into 20 equally populated bins, which were subjected to iPAGE analysis. The most informative functional categories are shown. (D) PA3726 promoter activity was measured as described in (B).