Research Paper Volume 5, Issue 4 pp 234—269

Figure 3. Under CR conditions,the atg32Δ-dependent mutational block of macromito-phagy alters the age-related dynamics of changes in mitochondrial size, number, shape, morphology and network appearance.

WT and atg32Δ strains were cultured in the nutrient-rich YP medium initially containing 0.2% glucose. (A) Transmission electron micrographs of WT and atg32Δ cells recovered on day 1, 2 or 4 of cell culturing. M, mitochondrion. Bar, 1 μm. (B) Percentage of mitochondria in WT and atg32Δ cells having the indicated relative area of mitochondrion section. The relative area of mitochondrion section was calculated as (area of mitochondrion section/area of cell section) × 100. Data are presented as means ± SEM (at least 100 cells of each strain were used for morphometric analysis at each time-point). (C) Numbers of mitochondria in WT and atg32Δ cells. The data of morphometric analysis are expressed as the number of mitochondria per μm³ of cell section ± SEM (at least 100 cells of each strain were used for morphometric analysis at each time-point). (D) Morphology of mitochondria in WT and atg32Δ cells recovered on day 1, 2 or 4 of cell culturing. Mitochondria were visualized by indirect immunofluorescence microscopy using monoclonal anti-porin primary antibodies and Alexa Fluor 568-conjugated goat anti-mouse IgG secondary antibodies. (E) The percentage of cells exhibiting fragmented mitochondria was calculated. At least 800 cells of each strain were used for quantitation at each time-point. Data are presented as mean ± SEM (n = 3).