A Quorum Sensing Regulated Small Volatile Molecule Reduces Acute Virulence and Promotes Chronic Infection Phenotypes
Figure 2
2-AA silences MvfR regulon in a subpopulation of cells and restricts HAQ mediated QS signaling relevant in acute infection.
(A) Quantification of pqsA-GFP(ASV) expression in PA14 cells in response to increasing 2-AA concentration (µg/ml); the error bar represents the standard deviation of the 6 replicates. The difference in fluorescence intensity at the peak was statistically significant at all concentrations with p values <0.005. (B) Expression of pqsA-GFP(ASV) in response to 2-AA (µg/ml). Images of total number of cells in the optical field as assessed by membrane staining (red) and bacterial cells expressing pqsA-GFP(ASV)(green). (C) Quantification of pqsA expressing cells (percentage of green/red) in response to each 2-AA concentration. (D) Production of HHQ in supernatants collected from PA14 cells (OD 2.0) with exogenously added 2-AA at 0–200 µg/ml HHQ levels were quantified in triplicate by LC/MS. The error bars represent the standard deviation from triplicate samples. (E) Levels of pyocyanin in PA14 cultures grown (to OD 3.0) in LB and LB supplemented with varying (0–200 µg/ml) concentrations of 2-AA. Error bars represent standard deviation of the triplicate samples. These experiments were repeated at least three times with similar results. (F) Kinetics of pyoverdine production in the presence of 100 and 200 µg/ml of 2-AA. (-) indicates no exogenously added 2-AA.