Figure 3. Schematic representation of a skeletonised mitochondrial network.

(a) The mitochondrion (magenta) is shown as acquired by epifluorescence microscopy. The cell outlines as detected by CellMask are depicted by the dashed, green line. (b) A topological skeleton was extracted from (a). The mitochondrial main branch is depicted in red and the outgrowths are shown in blue. The white squares indicate endpoints, and the yellow circles indicate junctions. Outgrowth can be assigned into three major types: Shown here are (i) isolated branches, (ii) isolated loops, and (iii) complex structures, which can either be nested loops (multiple loops without endpoints) or complexes containing both, loops and branches (one or more loops with one or more endpoints). (c) Loops (blue, red, and green) are treated as shapes and can be measured accordingly. Scale bar 5 μm.