Fig. 4

Short-term heat acclimation induces mitochondrial fission and promotes heat resistance in zebrafish embryos. (A–C) Short-term heat acclimation experiment at 33°C. (A) Survival rate in each group of embryos was determined after the indicated period of heat acclimation. n = 100, repeat = 3. *indicates p < 0.05, and ns indicates p > 0.05. (B) Survival rates of the heat acclimation groups subjected to heat tolerance test at 39°C. n = 50 per experiment, repeat = 3. Statistical significance was determined between the control and the experimental groups, and the result was indicated above the experimental group. *indicates p < 0.05. (C) Representative images of liver mitochondrial morphology at 4 dpf in the heat acclimation groups as indicated. Scale bar = 5 µm. (D) Representative images of liver mitochondrial morphology in the indicated groups at 4 dpf. Scale bar = 5 µm. (E) Survival rate of embryos tested for heat tolerance in the indicated groups. n = 50 per experiment, repeat = 3. Statistical significance was determined between the control and the heat acclimation groups, and between the heat acclimation and the heat acclimation + Mdivi-1 groups as indicated. *indicates p < 0.05 and ns indicates p > 0.05. dpf, days postfertilization.