TMRE assay

For the TMRE staining experiments, C. elegans were grown until the early L4 larval stage and UVB-treated. TMRE staining at the indicated time points was done on NGM agar plates at a concentration of 30 μM dissolved with heat inactivated OP50 (30 min, 65°C). Once the plates were dry, animals were added via picking and left to take up the dye for 2 h. After staining, the animals were washed with M9 and moved to NGM plates spread with heat inactivated OP50 to avoid active bacteria from taking up the dye and staining the intestines of the worm. After 1 h crawling on the plates without the dye, the animals were washed and prepared for imaging as described in the mitochondrial mass assay. For large particle flow quantification the worms were washed into 50 ml falcons and fluorescence intensity levels were measured via the biosorter.