AhR Modulation during M. marinum Infection and RFB Treatment In Vivo (A) Cyp1a enzymatic activity (EROD) in 2 dpf embryos exposed to M. marinum for 24 h in E3 medium, in the presence or absence of 10 μM CH-223191. 1 representative of n = 3 independent experiments. Mean ± SD shown. (B and C) Bacterial loads in zebrafish embryos at 4 d post-systemic infection with Wasabi-expressing M. marinum (200 CFU), untreated or treated with RFB for 3 d, in the presence or absence of 10 μM CH-223191. 1 representative of n = 2 independent experiments. Mean ± SEM shown. (B) Representative micrographs. (C) Quantification of Wasabi-expressing M. marinum pixels per whole embryo. (A and C) Each data point depicts an individual zebrafish embryo, (C) while orange symbols indicate the individuals that were chosen as representative micrograph. Unpaired t test. ∗p ≤ 0.05, ∗∗p ≤ 0.01, ∗∗∗∗p ≤ 0.0001. See also Figures S7 and S8.