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Biomedical subjects

A A Simonian

Publications and source records attributed to A A Simonian.

At least 19 recordsLinked to original sources
PubMed1974

[Effect of cations and DNP on ATPase activity in different tissue fractions of birds' brains].

ATP-ase activity and the effect of cations (Na+, K+, Mg2+, Ca2+) and DNP on its activity have been studied in avian brain homogenates and mitochondrial and supernatant fractions (microsomes + hyaloplasma). Highest levels of Na+ + K+ -stimulated ATP-ase activity has been shown in avian brain crude mitochondrial fraction, next in supernatant and lowest in homogenates. Following three-fold freezing and thawing, enzyme activity in homogenates and mitochondrial fractions increases considerably and decreases in the supernatant. Highest Mg2+ -stimulated ATP-ase activity is found in avian brain homogenates, next in mitochondrial fractions and supernatants. Mg2+ -stimulated ATP-ase activity is not changed considerably following three-fold freezing and thawing of brain preparations. Highest Ca2+ -stimulated ATP-ase activity has been observed in the supernatant fraction and its activity is considerably reduced following freezing and thawing. Avian brain mitochondrial fractions have high DNP-stimulated ATP-ase activity. Following freezing and thawing of brain preparations DNP-stimulated ATP-ase activity is not changed considerably. The results obtained indicate that in avian brain homogenates and other preparations, cation and DNP-stimulated ATP-ase have different activities. Three-fold freezing and thawing of brain tissue preparations affect these activities differentially.

Adenosine Triphosphatases↗
PubMedDate not supplied

[Lipid peroxidation and oxidative phosphorylation in the heart and skeletal muscles of chickens developing under conditions of short-term cooling].

Studies have been made of the effects of short-term cooling of eggs at the second part of the incubation period on the intensity of oxidative phosphorylation and peroxidative oxidation of lipids in the mitochondria of skeletal muscles and heart from the developing chicks. It was shown that the intensity of respiration and phosphorylation increases in both tissues, being more significant in skeletal muscles. It is suggested that activation of peroxidative oxidation of lipids at the background of the increasing oxygen consumption and phosphate esterification during adaptation of animals to changes in the environment is one of the mechanisms accounting for the compensatory changes in fatty acid composition of lipids.

Animals↗
PubMedDate not supplied

[The effect of egg incubation temperature on the activity of cytochrome oxidase and anionic ATPase in chicken ontogenesis].

The short-term cooling of hen eggs under incubation was studied for its effect on the dynamics of the activity of cytochrome oxidase (CO) and anion ATPase in the brain and liver of 15- and 20-day hen embryos and 5-day chickens. The temperature fall in the embryonal period was established to stimulate the activity of bicarbonate-dependent ATPase in the brain and to suppress it in the liver tissue. The CO activity was also subjected to similar alterations.

Adenosine Triphosphatases↗
PubMedDate not supplied

[Changes in lactate dehydrogenase activity in chicken tissues in hyperthyreosis in ontogenesis].

The lactate dehydrogenase activity in reactions of lactate oxidation and synthesis was studied in subfractions of the chicken brain, heart and liver at the embryonal, early postembryonal and adult stages of development after thyroxine administration. It has been shown that during embryogenesis thyroxine predominantly enhanced the rate of lactate oxidation in the mitochondrial tissues. A marked increase in the lactate synthesis was found in cytoplasm of the adult chicken tissues. Specificity of enzyme activity alterations was detected in the chicken brain during ontogenesis after thyroxine administration.

Animals↗
PubMedDate not supplied

[Biochemical mechanisms of temperature adaptation in the chick embryo].

The effect of a short-term cooling of the incubated eggs has been investigated on the intensity of oxidative phosphorylation and the activity of ATPase in mitochondria from muscles and liver of chick embryos and chicks. It was found that the decrease of temperature increases oxygen consumption in muscle mitochondria decreasing esterification of inorganic phosphate. As a consequence, the value of P/O decreases. The activity of ATPase significantly increases. Uncoupling between oxidation and phosphorylation in liver mitochondria takes place more slowly. It is suggested that these changes account for realization of thermoregulation.

Adenosine Triphosphatases↗