Fig. 1.

Mitochondrial network connectivity depends on muscle fiber type. a 3D rendering of perpendicularly oriented glycolytic muscle mitochondrial network partially overlaid on raw serial block face scanning electron microscopy (SBF-SEM) data. b Grid-like oxidative muscle mitochondrial network partially overlaid on raw focused ion beam scanning electron microscopy (FIB-SEM) data. c Parallel cardiac muscle mitochondrial network partially overlaid on raw FIB-SEM data. d 3D rendering of connected subnetworks within the glycolytic muscle mitochondrial network. Each color represents a connected mitochondrial subnetwork. e Connected subnetworks within the oxidative muscle mitochondrial network. f Connected subnetworks within the cardiac muscle mitochondrial network. g Mitochondrial volume as a percent of total muscle volume. glycolytic, n = 5; oxidative, n = 4; cardiac, n = 4 datasets. h Quantification of mitochondrial network orientation. Dotted line represents parallel equal to perpendicular. glycolytic, n = 4; oxidative, n = 3; cardiac, n = 3. i Mitochondrial subnetwork volumes. glycolytic, n = 674 subnetworks, 4 datasets; oxidative, n = 1558 subnetworks, 4 datasets; cardiac, n = 522 subnetworks, 3 datasets. Points are means for each dataset. Bars represent muscle type overall mean ± SE. *Significantly different from glycolytic, ⁺significantly different from oxidative. Significance determined as p < 0.05 from one way ANOVA with Tukey’s HSD (variances not different) or Dunn’s multiple comparisons (variances different) post hoc tests. Scale bars – 5 µm