Mitochondrial perturbation due to overproduction of AtWhy2. A. Activity of mitochondrial respiratory chain complexes in plants with altered expression of atwhy2. BN-PAGE was used to separate membrane protein complexes from crude mitochondrial fraction taken from plants of the indicated genotypes. Activity of the different complexes was evaluated by in-gel enzymatic assays using equivalent protein amounts for all plants. B. Mitochondria ultrastructure was evaluated using transmission electron microscopy. In the upper panel, representative mitochondria from the indicated genotypes were photographed at 25000 × magnification. The bar represents 0.5 μm. In the lower panel, organelles were observed at 100000 × magnification. The bar represents 100 nm. Black arrows point to invaginations of the inner membrane (cristae).