Fig. 2.
(A) Lactate production of primary fibroblasts from humans, rats, humpback whales, and Weddell seals exposed to hypoxia (0.5% O2) for 6 hours. Relative lactate production is percent increase over the experimental period, normalized to absorbance of crystal violet stain in the same wells as a metric for number of cells present. Lactate production differed between species (F3,12 = 6.89, p = 0.006) with significant pairwise posthoc differences between the Weddell seal and both the human and the rat. (B) Relative cell proliferation in human, rat and Weddell seal fibroblasts after 18-h incubation at 37 °, 25 ° or 4 °C differed between species (F2,42 = 7.6, p = 0.0015) and across temperatures (F2,42 = 38.5, p < 0.0001) with a significant interaction term between these factors (F4,42 = 2.71, p < 0.04). Relative proliferation was detected as percent change in crystal violet stain, and plotted as normalized to human fibroblast proliferation at 37°C). # denotes a significant posthoc difference between Weddell seal and humant at 25 °C (p = 0.006), $ denotes a significant posthoc differences between Weddell seal and both human (p = 0.002) and rat (p = 0.01) at 4°C.