FIG 4.

Transcriptional activation of a malA-lacZ chromosomal fusion in B. thailandensis. Growth-adjusted β-galactosidase activity is shown as a percentage of wild-type control values. The open bars indicate activity in the absence of trimethoprim, and the solid bars indicate activity in the presence of 15 μg/ml trimethoprim. Parent, B. thailandensis with the malA-lacZ chromosomal reporter (BT01447); MalR⁻, BT01447 with a malR deletion (TT04); AHL⁻, BT01447 with deletions of all three of the AHL synthase genes (ΔbtaI1-3) (TT10); AHLs, 5 μM (each) C₈-HSL, 3OHC₈-HSL, and 3OHC₁₀-HSL; TpR, BT01447 with the dhfrII gene conferring trimethoprim resistance inserted in the neutral chromosomal attn7 site (TT05). The values are the means and ranges of the results from two independent experiments. Statistical analysis was done with a t test compared to the untreated parent; *, P ≤ 0.05.