[The cytochrome c oxidase activity in mitochondria of cardiomyocytes of isolated cardiac tissue under long-term hypoxic incubation].

Using method of electron microscopic histochemistry based upon the oxidative polymerization of 3,3'-diaminobenzidine (DAB) to reveal cytochrome c oxidase activity we identified that long hypoxic incubation of isolated small pieces of cardiac tissue during 72 h caused changes in mitochondrial ultrastructure followed by a breach of functional activities of mitochondria, and, in particular, complex IV of the respiratory chain. But for all that, small electron-dense mitochondria appearing inside electron-light mitochondria ("mitochondria inside mitochondria") stained positively for cytochrome c oxidase activity along the full length of cristaes. The results obtained are discussed in connection with conception of changes in the mitochondrial reticulum ultrastructure during mitoptosis.

[Dynamics of mitochondrial ultrastructure in small pieces of cardiac tissue under long-term anoxic incubation].

Anoxic incubation of isolated small pieces of cardiac tissue for 72 h caused emergence of an unusual population of mitochondria, referred to as "mitochondrion inside mitochondrion". We studied dynamics of the origin of this event. In the most part of a mitochondrial population after a 6 h anoxic incubation of myocardial tissue, a local increase in some region of the intermembrane space was observed.

[Local coupling of respiration processes and phosphorylation in rat liver mitochondria].

One variant of the model of the local coupling of phosphorylation and respiration in intact mitochondria was experimentally verified. The model is based on the following postulates: (1). Upon the functioning of H+ pumps, hydrogen ions bound to the outer membrane surface do not enter the aqueous phase but are utilized for ATP synthesis in the membrane supercomplex respiratory H+ pump--ATP synthetase.

Functional activity and ultrastructure of mitochondria isolated from myocardial apoptotic tissue.

Apoptosis in myocardial tissue slices was induced by extended incubation under anoxic conditions. Mitochondria were isolated from the studied tissue. A new method of isolation of mitochondria in special conditions by differential centrifugation at 1700, 10,000, and 17,000 g resulted in three fractions of mitochondria.

[Detection and functional role of local gradients of H+-ions on the intracellular mitochondrial membrane with covalently linked pH-probe].

The study is devoted to the registration of local H+ gradients on the inner membrane of mitochondria under conditions of H+ pump functioning were recorded. By using a covalently linked pH probe (fluorescein isothiocyanate), a local increase in the activity of hydrogen ions on the outer face of the inner mitochondrial membrane in the presence of the respiration substrate at increased permeability of the membrane for K+ was registered. It was also found that the buffer capacity of medium affects the respiration rate of completely uncoupled mitochondria; a change in respiration rate strictly correlates with changes in local H+ gradients on the mitochondrial membrane.