RNA expression of investigated target genes in A. castellanii strain Neff after challenge with 750 μM H₂O₂ for two (H2) and six (H6) hours and 2 mM diamide for two (D2) and six (D6) hours. (a) Thioredoxin 1 (Trx-1), peroxiredoxin 2 (Prx-2), peroxiredoxin 3 (Prx-3). (b) Glutaredoxin 1 (Grx-1), glutaredoxin 2 (Grx-2), glutathione peroxidase (Gpx); C: untreated control. The y-axis indicates – fold increase of RNA levels as compared to untreated controls. Error bars show the standard deviation of the mean (SEM). All values were obtained from at least three biological replicates in triplicate. *p < 0.05, **p < 0.01, and ***p < 0.0001 according to statistical analysis (multiple comparisons with a Kruskal–Wallis test on ranks followed by Dunn’s post hoc test).