Table 2.

P. aeruginosa PAO1 cellular and external AI concentrations

CompoundExternal concnaCellular concnbRatio of cellular to external concnc
[3H]3OC12-HSL69.1 ± 6.03 nM231 ± 16.8 nM3.35
[3H]C4-HSL56.4 ± 6.93 nM51.9 ± 11.4 nM0.92
[14C]ethylene glycol2.10 ± 0.07 mM2.00 ± 0.06 mM0.96
  • a Calculated from the amount of radioactivity remaining above the silicone fluid after centrifugation. Values are the averages ± SDs from three or four experiments.

  • b Calculated from the amount of radioactivity centrifuged through silicone fluid and the cell volume, with a correction for the small amount of extracellular material carried through the silicone fluid (measured with [14C]dextran). Values are the averages ± SDs from four independent experiments.

  • c An unpaired t test determined that the ratio of 4.4 for 3OC12-HSL was significantly higher than the ratio of 0.92 for C4-HSL (P < 0.001) and the ratio of 0.96 for ethylene glycol (P < 0.001).