Figure 3

L-Tyr reduces M. marinum levels in adult zebrafish granulomas. (a) Adults were intraperitoneally infected with approximately 400 CFUs of wild-type M. marinum strain/fish for 14 days. Adults were orally administered daily with 20 amino acids (effective concentrations) for 1 week before infection and for 2 weeks after infection. As a positive control, at 7 days post-infection (dpi), fish were orally administered RFP (50 mg/kg) daily until 14 dpi. (b) Histopathology showing whole fish sections and bacterial titers. Hematoxylin and eosin or acid-fast staining shows zebrafish infected for 14 days and granuloma comparisons between M. marinum-infected adults treated with/without L-Tyr and scored for M. marinum burden (> or <10 bacteria) or (c) necrotic granuloma percentages in fish (d). Individual values are shown with scatter dot plots in Student’s t-tests (a), and Fisher’s exact tests (c,d) were used for analyses. Scale bar = 20 μm in (b).