Figure 4. Evaluation of the R101SPM inhibitory effect on P. aeruginosa.

(A) Determination of MIC₅₀ for growth inhibition of strain PCZ. Fresh PCZ cells were inoculated with the initial OD₆₀₀ of 0.03 in LB medium (blue circle) or LB medium containing 0.7mM spermidine (red square). R101SPM was added as indicated, and the cells were grown at 37 °C with shaking at 250 rpm for overnight. Bacterial growth was measured by reading OD₆₀₀. (B) Determination of MIC₅₀ for TTSS inhibition of PCZ. Overnight cells were inoculated with 0.1% dilution in LB medium (blue circle, left y-axis) or LB medium containing 0.7 mM spermidine (red square, right y-axis). Samples were collected at 4^th hour post inoculation for the β-galactosidase activity assay.