A technique which incorporates a brief blending step to disperse callus tissue into small clumps of cells was developed, and the effects of cytokinins on respiration of soybean (Glycine max [L.] Merrill var. Acme) callus tissue prepared in this way were studied. Adenine alone did not affect respiration, but kinetin and zeatin showed effects correlating with their reported effects on growth of t...

The Bcl-2-related protein Bax is toxic when expressed either in yeast or in mammalian cells. Although the mechanism of this toxicity is unknown, it appears to be similar in both cell types and dependent on the localization of Bax to the outer mitochondrial membrane. To investigate the role of mitochondrial respiration in Bax-mediated toxicity, a series of yeast mutant strains was created, each ...

Energy metabolism in gastrobiopsy specimens of the antral and corpus mucosa, treated with saponin to permeabilize the cells, was studied in patients with gastric diseases. The results show twice lower oxidative capacity in the antral mucosa than in the corpus mucosa and the relative deficiency of antral mitochondria in complex I. The mucosal cells expressed mitochondrial and cytosolic isoforms ...

The role of cardiolipin in mitochondrial energy transformation was studied by comparing oxidative phosphorylation in the Saccharomyces cerevisiae cardiolipin synthase null mutant crd1Delta, and in isogenic wild type. Oxygen consumption experiments and membrane potential kinetics during the phosphorylation cycle in isolated mitochondria indicated that the absence of cardiolipin causes only a mod...

Oxidative phosphorylation and photophosphorylation have been found to respond differently to various inhibitors. Ammonia inhibits photophosphorylation at low concentrations (I), whereas high concentrations are required to uncouple oxidative phosphorylation (2). Dinitrophenol, on the other hand, is a more potent uncoupler of oxidative phosphorylation than of photophosphorylation (3). Oligomycin ...

The dynamic computer model of oxidative phosphorylation developed previously and successfully tested for large-scale changes in fluxes and metabolite concentrations was used to study the question of how the rate of ATP production by oxidative phosphorylation is adjusted to meet the energy demand during muscle contraction, which causes a great increase in ATP consumption in relation to the resti...

When the rate of respiration of mitochrondria in the presence of inorganic phosphate cannot be increased by adding adenosine diphosphate (A.D.P.) but these particles can still couple respiration to phosphorylation of A.D.P. to adenosine triphosphate (A.T.P.), the state of respiration is called 'loosely coupled'. The first patient in whom such a loosely coupled state of oxidative phosphorylation...

To study the mechanisms of mitochondrial dysfunction due to ischemia-reperfusion (I/R) injury, rat hearts were subjected to 20 or 30 min of global ischemia followed by 30 min of reperfusion. After recording both left ventricular developed pressure (LVDP) and end-diastolic pressure (LVEDP) to monitor the status of cardiac performance, mitochondria from these hearts were isolated to determine res...

Oxidative phosphorylation requires assembly of the protein products of both mitochondrial and of nuclear genomes into functional respiratory complexes. Cellular respiration can be compromised when mitochondrial DNA (mtDNA) sequences are corrupted. Oxidative damage resulting from reactive oxygen species (ROS) produced during respiration is probably a major source of mitochondrial genomic instabi...