No abstract

We have examined the ultrastructure of mitochondria as it relates to energy metabolism in the intact cell . Oxidative phosphorylation was induced in ultrastructurally intact Ehrlich ascites tumor cells by rapidly generating intracellular adenosine diphosphate from endogenous adenosine triphosphate by the addition of 2-deoxyglucose . The occurrence of oxidative phosphorylation was ascertained indirectly by continuous and synchronous monitoring of respiratory rate, fluorescence of pyridine nucleotide, and 90° light-scattering . Oxidative phosphorylation was confirmed by direct enzymatic analysis of intracellular adenine nucleotides and by determination of intracellular inorganic orthophosphate . Microsamples of cells rapidly fixed for electron microscopy revealed that, in addition to oxidative phosphorylation, an orthodox -> condensed ultrastructural transformation occurred in the mitochondria of all cells in less than 6 sec after the generation of adenosine diphosphate by 2-deoxyglucose . A 90° light-scattering increase, which also occurs at this time, showed a t 12 of only 25 sec which agreed temporally with a slower orthodox ---> maximally condensed mitochondrial transformation . Neither oxidative phosphorylation nor ultrastructural transformation could be initiated in mitochondria in intact cells by the intracellular generation of adenosine diphosphate in the presence of uncouplers of oxidative phosphorylation . Partial and complete inhibition of oxidative phosphorylation by oligomycin resulted in a positive relationship to partial and complete inhibition of 2-deoxyglucose-induced ultrastructural transformation in the mitochondria in these cells . The data presented reveal that an orthodox -* condensed ultrastructural transformation is linked to induced oxidative phosphorylation in mitochondria in the intact ascites tumor cell.