Comparative oxidation of erucic and oleic acids by mitochondria isolated from heart auricle of living man]

Mitochondria were isolated from fragments of heart auricles, that were cut off during surgical intracardiac operations. They were incubated with either [14 14C] erucic acid or [10 14C] oleic acid as a control. In the experimental conditions used, the radioactive products soluble in perchloric acid, that are issued from the beta-oxidation reactions in mitochondria, were formed in much lower amounts from erucic acid than from oleic acid. These results show the very low capacity of human heart mitochondria to use directly erucic acid as a substrate for energy requirements, as has been observed before with other animal species. Activation of fatty acids, the preliminary step of their beta-oxidation, was also observed to be very much lower with erucic acid.     

Depression by ethionine of phosphorylating oxidation in hepatic mitochondria

Induction of hepatic steatosis and suppression of hepatic ATP levels, protein synthesis and gluconeogenesis subsequent to administration of ethionine may be consequences of interference by this compound with mitochondrial phosphorylation of ADP. The mitochondrial dysfunction is not a direct action of ethionine on the organelle.     

Depression by ethionine of phosphorylating oxidation in hepatic mitochondria

Summary Induction of hepatic steatosis and suppression of hepatic ATP levels, protein synthesis and gluconeogenesis subsequent to administration of ethionine may be consequences of interference by this compound with mitochondrial phosphorylation of ADP. The mitochondrial dysfunction is not a direct action of ethionine on the organelle.     

Regulation of glutamate pyruvate transaminase in the amphibian (Rana hexadactyla) kidney and liver homogenates

Zusammenfassung Die Wirkung der Protein- und Aminosäurebelastung auf die Glutamat-Pyruvat-Transaminase in Niere und Leber vonRana hexadactyla wurde untersucht. Die Enzymaktivität war in der Niere höher als in der Leber.-Globulin und Lysin erhöhte die Leberenzyme und war ohne Einfluss auf die Nieren-Transaminase.     

Progesterone stimulates energy-dependent contraction of swollen heart mitochondria

Summary Progesterone stimulates the rate and efficiency of respiration-dependent contraction of heart mitochondria in nitrate salts at alkaline pH. Ion extrusion under these conditions is normally slow and inefficient due to the elevated permeability of the membrane to monovalent cations through a putative uniport pathway. Progesterone also inhibits passive swelling under these conditions and appears to act by restricting cation influx through the uniport pathway.This study was supported in part by United States Public Health Service grant No. HL09364.     

Some properties of external NADH oxidation by human placental mitochondria

Summary Isolated human term placenta mitochondria catalyse oxidation of external NADH in the presence of cytochrome c. This reaction is insensitive to the respiratory chain inhibitors such as rotenone and antimycin A, and is not coupled to phosphorylation. Comparison of the effect of Mg⁺⁺ ion on NADH plus cytochrome c oxidation by human term placental, human skeletal muscle and rat skeletal mitochondria showed that Mg⁺⁺ ion exerts an inhibitory effect in the case of human mitochondria and a stimulatory effect in the case of rat skeletal muscle mitochondria.This work has been supported by a grant from Ministry of Higher Education Science and Technology within the project No. 01.02.     

Proline synthesis from glutamate in the mitochondria isolated from a blowfly,Aldrichina grahami

Summary Proline biosynthesis from glutamate was demonstrated in a cell free system prepared from blowfly abdomen. The biosynthetic activity was found mainly in the mitochondrial fraction. The biosynthesis of proline from glutamate required ATP, NADPH and Mg⁺⁺ as cofactors.     

Enhancement of oxidation products of lipids in liver mitochondria of whole-body irradiated rats

Zusammenfassung Der Einfluss der ionisierenden Strahlung auf die Bildung der Oxydationsprodukte von ungesättigten Fettsäuren in Lebermitochondrien ganzkörperbestrahlter Tiere wurde untersucht. Die TBS-Chromogenwerte erhöhen sich in bestrahlten Mitochondrien statistisch signifikant und sinken in 12 h nach der Bestrahlung wieder zur Norm ab.     

Deoxyribonucleic acid synthesis in the heart mitochondria after acute and exhaustive exercise

Resumen Las mitocondrias del corazón de ratas sometidas a natación forzada muestran filamentos considerados morfológicamente como de ADN y captan timidina tritiada. Sobre la base de estas observaciones se sugiere que las mitocondrias miocárdicas con capaces de una activa síntesis de ADN como respuesta a requirimientos funcionales agudos.     

Some properties of external NADH oxidation by human placental mitochondria.

Isolated human term placenta mitochondria catalyse oxidation of external NADH in the presence of cytochrome c. This reaction is insensitive to the respiratory chain inhibitors such as rotenone and antimycin A, and is not coupled to phosphorylation. Comparison of the effect of Mg++ ion on NADH plus cytochrome c oxidation by human term placental, human skeletal muscle and rat skeletal mitochondria showed that Mg++ ion exerts an inhibitory effect in the case of human mitochondria and a stimulatory effect in the case of rat skeletal muscle mitochondria.     

Interaction between uncouplers of oxidative phosphorylation andStaphylococcus aureus infected liver mitochondria

Résumé Des microphotographies électroniques de mitochondries du foie de souris infectées par des staphilocoques montrent une décroissance de la population énergisée, ce qui suggère un découplement. Les mitochondries du foie des animaux infectés avaient un taux élevé d'absorption d'oxygène et indiquent une action de découplement de laS. aureus plus effective que celle du dinitrophenol employée in vitro dans une concentration optimale. Le découplement semble avoir lieu au stage de phosphorylation de l'oxydation.