Broad-Spectrum Anti-biofilm Peptide That Targets a Cellular Stress Response (original) (raw)
Figure 5
Modulation of relA expression impacts on biofilm development.
(A) relA expression modulated biofilm formation and disassembly. The relA gene under the control of an arabinose-inducible promoter was introduced into a P. aeruginosa PAO1 Δ_relAspoT_ background. Induction of relA led to biofilm formation in flow cells after 3 days. On the other hand, induction of relA for 2 days followed by 24 h of non-induction led to biofilm dispersal. Biofilm biovolume was calculated using Imaris software from Bitplane AG. Experiments were performed at least in triplicate. Student's t test was used (****, P<0.0001). (B) Repression of relA expression (after 2 days of induction) led to biofilm dispersal in a P. aeruginosa PAO1 Δ_relAspoT_ strain, while continuous induction of relA expression during the 3 days of the experiment resulted in significantly fewer cells dispersed from biofilms. Dispersed cells from 2-day old biofilms were collected and viable cell counts performed 3 and 6 h after induction of relA expression was either stopped or continued. Statistical significance was determined using Student's t test (*, P<0.05).