Fig. 2: Reduced ATPase activity in hibernating muscle fibers.
From: Reduced ATP turnover during hibernation in relaxed skeletal muscle
a Average ATPase activity of skinned fibers taken from individual bears in winter and summer. Each point represents a single fiber taken from a specific biopsy (n = 8-27, Source data are provided as a Source Data file). On the right the average ATPase activity divided by season, in which a decrease in ATPase activity is measured in winter compared to summer (summer n = 9, winter n = 11. mean ± SEM, two-sided Mann-Whitney test P value < 0.0001). b Decaying fluorescence traces of mantATP chasing experiments in skinned fibers from summer and winter bear muscle biopsies (n = 19 single fibers for summer samples and n = 19 single fibers for winter samples, each fluorescence decay are fitted with the triple exponential decay shown in the material and methods). Fitted parameters are reported on the right, as winter biopsies showed a significant reduction in both DRX (T1. mean ± SEM. Two-sided Unpaired t-test, P value 0.0058) and SRX (T2. mean ± SEM. Two-sided Unpaired t-test, P value 0.0023) time constants, indicating a slower overall nucleotide release. All data related to summer samples are reported in orange/red color, while those related to winter are in light blue/blue.
