Figure 21. Human fibroblasts showing colocalization of mitochondria with lysosomes. The degree of colocalization of mitochondria with lysosomes in human fibroblasts was measured via live cell imaging microscopy at 37°C and 5% CO₂ atmosphere using the ApoTome^® technique. LysoTracker^® Red DND-99 staining was applied to mark lysosomal structures (red), and MitoTracker^® Green FM to visualize mitochondria (green). Hoechst 33342 dye was used to stain nuclei (blue). A positive colocalization is indicated by yellow signals (merge) due to the overlap of LysoTracker^® Red and MitoTracker^® Green staining (white arrows). Scale bar, 10 µm. Statistical evaluation is performed by calculating the Pearson’s coefficient for colocalizing pixels. Image provided by L. Burbulla and R. Krüger.