Change in embryonic TCDD concentration over time. Zebrafish were exposed to either a 50 ppt (grey boxes), 1 ppb (green dimonds), or 10 ppb (black circles) solution of TCDD for 1 hour at 4 h post-fertilization (hpf). Samples were fixed at 24, 48, and 72 hpf and TCDD was quantified at each time point. The 10 ppb and 1 ppb exposures were best modeled by exponential decay while the 50 ppt was best described by linear elimination. The asterisk (*) denotes a statistically significant difference between the 10 ppb and 1 pbb exposure groups (t-test). At 24 and 72 hpf, there was significantly more TCDD present per embryo in the 10 ppb exposure group (p = 0.1167 and p = 0.0001) when compared to the 1 ppb exposure group.

Manhattan plots of the negative ionization mode log10 transformed p-values describing the association between m/z features and the 50 ppt (A, B, & C)) and 10 ppb (D, E, & F) TCDD exposures at 24, 48, and 72 hpf. Blue circles represent features that were downregulated in comparsion to the control group, whereas orange triangles represent features that were upregulated . The black line indicates the p-value corresponding to a false discovery rate (FDR) threshold of 0.2.

Manhattan plots of positivelog10 transformed p-values describing the association between m/z features and the 50 ppt TCDD exposure (A, B, & C) as well as the 10 ppb TCDD exposure (D, E, & F) at 24, 48, and 72 hpf. . Blue circles represent features that were downregulated in comparsion to the control group, whereas orange triangles represent features that were upregulated . The black line indicates the p-value corresponding to a false discovery rate (FDR) threshold of 0.2.

Venn diagram displaying the overlap of significant features in each ionization mode. Depicted are the total number of features determined to be significant (FDR>20%) in negative (A) and positive (B) ionization. The overlap represents features that were significant at multiple time points (24, 48, and/or 72 hpf). The number in the white box represents the total number of significant features found in samples at the labeled time point.

Enriched pathways associated with the 10 ppb TCDD exposure group. Results are shown for pathways that had at least 5 significant metabolites in both the negative and positive ionization mode . The size of the dot represents the number of overlapping metabolites in the pathway. The position of the dot is determined by the -log p-value obtained from 10,000 permutations. The black vertical line indicates significance