Biochemical and molecular consequences of ethidium bromide treatment on Drosophila cells

KC167 Drosophila cells were incubated with low concentrations of ethidium b romide (200 ng/ml), causing changes in mitochondrial DNA (mtDNA) content (2 -184% of that of controls). SSCP (single strand conformational polymorphism ) analysis of mtDNA indicated that the incubation with ethidium bromide als o generated mutations. Compared with controls, there were marked reductions in the activities of respiratory complexes III and IV measured in these ce lls, and in respiration and ATP synthesis capacities measured in isolated m itochondria. These reductions matched that in mtDNA content, in contrast, n o link could be demonstrated between mtDNA content and steady-state concent rations of the transcripts of genes COIII and Cyt b. (C) 1999 Elsevier Scie nce Ltd. All rights reserved.