Mutants with a transposon insertion in the sypIJKL operon have enhanced qrr1 expression. (A) Levels of qrr1 expression in WT (ES114), ΔluxO (TIM306), sypI::Tn5 (DRO5F11), sypJ::Tn5 (DRO1B3), and sypI::Tn5 [NT] (DRO222) harboring the reporter plasmid pTM268. The nonfluorescent strain ES114 harboring pVSV105 was used to calculate cellular levels of GFP and mCherry. Graphical and error bars represent the averages and standard deviations of triplicate biological replicates, respectively. One-way ANOVA with Tukey's multiple comparisons test show significance (P-value <0.01) between columns, except for the comparison labeled not significant (n.s.). Experiment was performed three times, with similar results. (B) Transposon insertion sites of mutants examined in (A). Genes disrupted by a transposon are highlighted in gray. Arrows above transposon insertions indicate direction of erm gene transcription. (C) Luminescence levels of WT (ES114), Δlux (EVS102), sypI::Tn5 [NT] (DRO222), Δqrr1 (TIM305), ΔluxO (TIM306), and ΔlitR (TIM358) in response to 120 nmol/L 3-oxo-C6. Graphical and error bars represent the averages and standard deviations of triplicate biological replicates, respectively. One-way ANOVA with Tukey's multiple comparisons test on log-transformed data show significance (P-value <0.01) between columns, except for the comparison labeled not significant (n.s.). Experiment was performed three times, with similar results.