Terminal respiration in minute mutants of Drosophila

Abstract

Oxidative phosphorylation was studied in mitochondria isolated from third instar larvae heterozygous for the following Minute mutations: M(2)S-10, M(2)12, M(2)1, M(3)y and M(3)l. The substrates utilized inculded a-ketoglutarate, pyruvate with malate, succinnte, a-glycerophosphate and ascorbate. Mitochondria from an additional mutant, M(2)z, were also tested for their ability to metabolize a-glycerophosphate. Abnormalities associated with the cytochrome b-c site of phosphorylation were evident in all mutant genotypes. Additional lesions at the substrate level and at the DPN-DPNH site of phosphorylation in the electron transport system were also identified in one or more of the mutants analyzed.