Figure 6.

Characterization of complex I and CO activity in AD and control cybrids expressed as a rate for complex I (nmol⋅min⁻¹⋅mg⁻¹) and a relative rate for CO (min⁻¹⋅mg⁻¹). CO activity was significantly decreased in AD cybrids relative to control cybrids (t test, P < 0.001). In contrast, complex I activity, another complex encoded in part by the mitochondrial genome, was not different in a subset of AD and normal control cybrids. Each bar represents the mean group activity. Error bars are SEM. To confirm that cells were true cybrids and not hybrids, putative cybrid cells were cultured and harvested using standard cytogenetic techniques. They were then stained with the GTG (Giemsa–trypsin–Giemsa) technique, and chromosomes were counted.