Figure 2. Summarized inhibitory activity of spermine conjugates on TTSS in P. aeruginosa.

Overnight grown culture was diluted with a ratio of 1:1000 in LB supplemented with specified compounds. Final concentration of the compounds were 50 μM except that R101SPM, R101SPD and RBSPM, whose were 20 μM in the medium. After 4 hr shaking at 37 °C, cells were harvested and washed with PBS once prior to the β-galactosidase activity assay. Culture in absence of compounds was included as controls and the activity (average ± SD) was presented as the percentage of β-galactosidase activity for tested compounds relative to the control. All experiments were repeated three times with duplicates.