Figure 2.

Cold acclimation preserves paracellular barrier function before and during chilling stress. (A) The gut of a cold-acclimated female Drosophila melanogaster adult after feeding on FITC-dextran for 24 h. Note that FITC-dextran is distributed through the entire gut. (B) representative samples of hemolymph taken from warm- and cold-acclimated flies prior to any cold exposure. Images were taken with identical microscope settings. (C) Mean ± sem concentrations of FITC-dextran (log₁₀ scale) in the hemolymph of warm- (red) and cold-acclimated (blue) flies (n = 5–9 samples per group × exposure duration) before and following exposure to 0 °C for up to 24 h. Warm-acclimated flies had higher levels of FITC-dextran leak into the hemolymph prior to cold stress, and chilling caused FITC-dextran to leak at greater rates into the hemolymph of both acclimation groups.