Catalase knockdown in the midgut.

<p>(A) Two-day-old females were injected with dsRNA against catalase (dsCat) or an unrelated control gene (dsLac). Two days after the dsRNA injection, a group of mosquitoes were fed blood, while others were fed exclusively with sugar. Twenty-four hours later, RNA was extracted for qPCR analysis. (B) Catalase activity in the epithelia was measured 24 h after a blood meal in dsRNA-treated mosquitoes. (C) Hydrogen peroxide leakage was measured in the midgut epithelia of SF mosquitoes injected with dsCat or dsLacZ. (A) *** <i>p <</i> 0.001 (t-test). (B) **** <i>p <</i> 0.0001 (t-test). (C) * <i>p</i> = 0.0404 (t-test).</p

Catalase knockdown in the midgut.

<p>(A) Two-day-old females were injected with dsRNA against catalase (dsCat) or an unrelated control gene (dsLac). Two days after the dsRNA injection, a group of mosquitoes were fed blood, while others were fed exclusively with sugar. Twenty-four hours later, RNA was extracted for qPCR analysis. (B) Catalase activity in the epithelia was measured 24 h after a blood meal in dsRNA-treated mosquitoes. (C) Hydrogen peroxide leakage was measured in the midgut epithelia of SF mosquitoes injected with dsCat or dsLacZ. (A) *** <i>p <</i> 0.001 (t-test). (B) **** <i>p <</i> 0.0001 (t-test). (C) * <i>p</i> = 0.0404 (t-test).</p

Catalase mRNA and activity increased in the midgut epithelia of blood-fed mosquitoes.

<p><i>Aedes aegypti</i> females were fed sugar (SF) or blood (BF) and dissected at the indicated time points after a blood meal. (A) Catalase mRNA expression in the epithelia was evaluated using qPCR analysis of SF and BF mosquitoes. (B) Enzymatic activity was measured as described in the Materials and Methods section. (C) Catalase inhibition by AT <i>in vitro</i>. Midgut epithelia was collected from blood-fed mosquitoes 24 h after feeding and was incubated with AT and H₂O₂ for 30 min at 4°C; then, catalase activity was assayed. (D) Mosquitoes were fed blood supplemented with 15 mM AT and assayed for catalase activity in the epithelia *** <i>p <</i> 0.001. Figure 1A-B–ANOVA followed by Dunnett's multiple comparison test.</p

Catalase silencing impacted Dengue but not Zika midgut infection prevalence.

<p>(A) Females were fed blood contaminated with 10⁷ PFU/mL of Zika virus, and 7 days after feeding the number of PFU was determined in the midgut. (B) The percentage of infected midguts (infection prevalence) was scored from the same set of data as in A. (C) Mosquitoes were fed a lower dose of Zika-infected blood (10⁵/mL), and PFU/midgut was determined 7 days post-infection. (D) Infection prevalence of mosquitoes from C. (E) Mosquitoes were fed blood contaminated with 10⁶ PFU/mL of Dengue 4 virus, and PFU/midgut was counted 7 DPI. (F) Infection prevalence was determined from the same group of mosquitoes. Mann-Whitney <i>U</i>-tests were used for infection intensity (A, C, E), and chi-square tests were performed to determine the significance of infection prevalence analysis (B, D, F). Statistical values and number of replicates are depicted in the corresponding figures.</p

Catalase knockdown affected both resistance to H₂O₂ and oviposition.

<p>Catalase was silenced as described, and two days after dsRNA injection, SF (A) or BF (immediately after feeding) (B) mosquitoes were transferred to cages containing 5% sucrose supplemented with 1 M H₂O₂ <i>ad libitum</i> (day 0). A fresh H₂O₂ solution was provided daily. Survival was scored every 24 h. *** <i>p</i> < 0.0001 for the comparison between dsLacZ–H₂O₂ vs dsCat–H₂O₂ (log-rank test). (C) Catalase-silenced mosquitoes were blood-fed and allowed to lay eggs. Each dot represents an individual mosquito. LacZ–n = 21. Catalase–n = 25. * <i>p =</i> 0.37 (t-test).</p