Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:1.9.3.1 (cytochrome oxidase)
8,822 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To study the possible hepatotoxicity of vitamin A supplementation and its potentiation by ethanol, rats were fed diets with either normal or fivefold increased vitamin A content, both with or without ethanol. Ethanol with a normal vitamin A diet produced the expected proliferation of the smooth endoplasmic reticulum and moderate mitochondrial lesions. Vitamin A supplementation by itself produced endoplasmic reticulum proliferation, slight enlargement of mitochondria, and moderate decrease in cytochrome oxidase activity and cytochrome aa3 content. The combination of high vitamin A and ethanol resulted in much more striking lesions, with giant mitochondria containing paracrystalline inclusions and depression of oxygen consumption in state-3 respiration with five different substrates, including palmitate and palmitoyl coA. The depression of fatty acid oxidation may have contributed to the lipid accumulation. The blood levels of vitamin A were unaffected whereas liver levels of vitamin A were increased by vitamin A supplementation and decreased by ethanol. As a net result the liver vitamin A content of the high-A-ethanol groups was not greater than that of the normal-A-control group, suggesting that a metabolite of vitamin A rather than vitamin A itself may have been responsible for the potentiation of vitamin A toxicity by ethanol. Mitochondrial toxicity reflected itself also in decreased content of various cytochromes and reduced activity of enzymes, including glutamate dehydrogenase. The activity of the latter was increased in the serum. Implications of these findings for the routine treatment of alcoholics with vitamin A and the monitoring for possible signs of toxicity are discussed.
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PMID:Hepatotoxicity of vitamin A and ethanol in the rat. 627 29

The specific activity and content of cytochrome oxidase in the rough endoplasmic reticulum--mitochondrion complex are higher than in the mitochondrial fraction. Radiolabelling studies with the use of hepatocytes and isolated microsomal and rough endoplasmic reticulum--mitochondrion fractions, followed by immunoprecipitation with anti-(cytochrome oxidase) antibody, reveal that the nuclear-coded cytoplasmic subunits of cytochrome oxidase are preferentially synthesized in the latter fraction. The results have a bearing on the mechanism of transport of these subunits into mitochondria.
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PMID:Cytochrome c oxidase is preferentially synthesized in the rough endoplasmic reticulum--mitochondrion complex in rat liver. 629 69

Functional integrity of liver cell organelles in rats given the model abrupt cytotoxin 1,1-dichloroethylene (1,1-DCE) was examined by enzymatic histochemistry. Fasted 200-gm. male Sprague-Dawley rats were sacrificed 1, 2, 4, or 6 hours after an oral dose of 200 mg. of 1,1-DCE per kg. (in mineral oil) and 6 hours after 50, 100, or 150 mg. of 1,1-DCE per kg. Cubes of liver were quick frozen for histochemistry. Stage or degree of liver injury was assessed by histology and by measuring serum transaminase activities and liver ion levels. We found both early injury (2 hours following the 200-mg. per kg. dose) and slight injury (6 hours following the 50-mg. per kg. dose) characterized by: increases in liver sodium levels and striking decreases in the central area staining patterns of bile canaliculi membrane Mg++-ATPase, as well as of outer mitochondrial membrane monoamine oxidase and inner mitochondrial membrane succinate dehydrogenase and cytochrome oxidase. As injury progressed with time or increased in severity with dose, aberrations in the levels of other liver cell ions occurred, serum transaminase activities rose, and decreased staining of plasma membrane and mitochondrial membrane components were evident in progressively wider areas around the central vein. Glutathione depletion was panlobular. In contrast, only at later times (4 and 6 hours) and after the larger doses did alterations to functional components of the mitochondrial matrix, endoplasmic reticulum, lysosomes, and cytosol become evident in a narrow area around the central vein, which became necrotic. We consider these later appearing alterations secondary consequences of the midzonal necrosis and sinusoidal congestion produced by 1,1-DCE, whereas the plasma membranes and mitochondrial membranes appear to be primary foci of injury.
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PMID:Histochemical evidence that plasma and mitochondrial membranes are primary foci of hepatocellular injury caused by 1,1-dichloroethylene. 646 95

Lymph node cell homogenates were fractionated by differential or isopycnic centrifugation and the fractions analyzed for biochemical markers with particular focus on plasma membrane constituents. Markers for the nucleus (DNA), mitochondria (cytochrome oxidase), and lysosomes (acid hydrolases) showed the expected distributions which were different from those of membrane-bound enzymes. 5'-Nucleotidase, alkaline phosphodiesterase, gamma-glutamyltranspeptidase, and cholesterol were membrane-bound and distributed identically after isopycnic centrifugation with peaks at 1.15. The distributions of the enzymes were all shifted to higher densities by digitonin treatment, confirming their association with plasma membrane-derived elements. The distribution of galactosyltransferase (ovalbumin acceptor), largely overlapped those of plasma membrane markers but it was only slightly shifted by digitonin, suggesting its localization in Golgi apparatus. The distribution of mannosyltransferase (dolichyl phosphate acceptor) also overlapped those of plasma membrane and Golgi markers but it was centered at higher density (1.18) and was unaffected by digitonin. It is a useful marker for endoplasmic reticulum. 50% of the activity was in low speed "nuclear" sediments where it was associated with the nuclear membrane. A number of other putative and previously used markers for the endoplasmic reticulum of lymphocytes were shown not to be localized in these membranes. In particular, NADH-cytochrome c reductase was only partly associated with the endoplasmic reticulum (56%) and the remainder of the activity was in mitochondria (44%). The results show the heterogeneity in equilibrium density of plasma membrane vesicles and the considerable overlap of their distribution with those of other cellular membranes; they should provide a basis for the more rational design of preparative procedures for the lymphocyte plasma membrane.
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PMID:Characterization of rat lymphocyte cell membranes by analytical isopycnic centrifugation. 660 29

With the diaminobenzidine method, endogenous peroxidase activity was demonstrated in the nuclear envelope and in the endoplasmic reticulum of non-keratinized keratinocytes and Langerhans cells of the epidermis of the newborn mouse, adult guinea pig and man. In the guinea pig all non-keratinized layers of keratinocytes showed this enzyme activity, whereas in the two other species examined peroxidase activity was limited to the suprabasal layers. The most pronounced activity was found in the Langerhans cells. The melanocytes were negative. With the same method, cytochrome c/cytochrome oxidase activity could be localized in the mitochondria of all epidermal cells of mouse and man, but not in the guinea pig.
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PMID:Ultrastructural demonstration of endogeneous peroxidase activity in mammalian epidermis. 661 14

Endogenous peroxidatic activity has been demonstrated at the ultrastructural level in large arteries of rabbit and rat using diaminobenzidine. The reaction was positive in endothelial cells of both species and also in the smooth muscle cells of rat arteries. The reaction product was localized in the nuclear envelope and endoplasmic reticulum of the reactive cells. Since the enzymatic activity was extremely sensitive to fixation, best visualization was obtained in unfixed, directly incubated tissues in which additional mitochondrial staining occurred due to the activity of endogenous cytochrome c/cytochrome oxidase system. The peroxidatic activity was partially sensitive to cyanide and could be completely abolished by azide and aminotriazole. It has been suggested that the observed endogenous peroxidatic activity of the arterial wall components reflects the activity of prostaglandin endoperoxide synthetase and, indirectly, production of prostacyclin (PGI2).
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PMID:Ultrastructural demonstration of endogenous peroxidatic activity in mammalian arterial wall. 679 54

The subcellular site of oxidation of [1-14C]phytanic acid to pristanic acid and CO2 was examined by measurement of the release of 14CO2 in different organelles from human and rat tissues prepared by isopycnic density gradient centrifugation in Nycodenz. The activity of phytanic acid oxidation in human tissues (liver and cultured skin fibroblasts) paralleled that of the peroxisomal marker catalase. We also observed that Nycodenz (commonly used gradient material for isolation of subcellular organelles) has a strong inhibitory effect on the alpha-oxidation of phytanic acid. This inhibition is reversible and can be decreased or eliminated by dialysis of isolated organelles against isotonic solution. The dialysis of endoplasmic reticulum, mitochondrial, and peroxisomal fractions from human liver and cultured skin fibroblasts for 2 h against isotonic solution increased the specific activity of phytanic acid oxidation by 1.3-, 1.3-, and 5-21-fold, respectively, after removal of Nycodenz as compared with nondialyzed samples. After dialysis, the rate of oxidation of phytanic acid in peroxisomes from human liver and cultured skin fibroblasts was 4-26 times higher than that in mitochondria and 43-130 times than that in the endoplasmic reticulum, suggesting that, in human tissues, phytanic acid is oxidized to pristanic acid in peroxisomes. On the other hand, the oxidation of phytanic acid in rat liver paralleled the distribution of the mitochondrial marker cytochrome-c oxidase. The 18-fold higher rate of oxidation in dialyzed mitochondria (198.6 +/- 4.20 pmol/h/mg of protein) than in peroxisomes (11.0 +/- 0.5 pmol/h/mg of protein) demonstrates that, in rodents, phytanic acid is oxidized in mitochondria. 2-[5-(4-Chlorophenyl)pentyl]oxiran-2-carboxylic acid, an inhibitor of carnitine palmitoyltransferase I and mitochondrial fatty acid oxidation, inhibits the oxidation of phytanic acid in rat tissues (liver and cultured skin fibroblasts), whereas it has no effect on the oxidation of phytanic acid in human tissues (liver and cultured skin fibroblasts). The higher specific activity of phytanic acid oxidation in peroxisomes compared with that in mitochondria and the endoplasmic reticulum from human tissues and the inhibition of phytanic acid oxidation by 2-[5-(4-chlorophenyl)pentyl]oxiran-2-carboxylic acid in rat tissues (but not human tissues) demonstrate clearly that, in human tissues, phytanic acid is predominantly oxidized in peroxisomes.
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PMID:Phytanic acid alpha-oxidation. Differential subcellular localization in rat and human tissues and its inhibition by nycodenz. 848 24

Thick biological specimens prepared as whole mount cultured cells stained with histochemical reactions, such as thiamine pyrophosphatase, glucose-6-phosphatase, cytochrome oxidase, acid phosphatase, DAB reactions demonstrating specific cell organelles such as Golgi apparatus, endoplasmic reticulum, mitochondria, lysosomes, peroxisomes and pinocytotic vesicles, were observed by ultrahigh voltage electron microscopy at accelerating voltages of 400-1000 kV producing stereo-pairs. As a result, those cell organelles were observed 3-dimensionally and the relative relationships between these organelles demonstrated.
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PMID:Three dimensional observation of whole mount cultured cells stained with histochemical reactions by ultrahigh voltage electron microscopy. 853 71

The highly regulated intracellular concentration of calcium (Ca2+) is a well-described regulator of diverse cellular events, including cell cycle control. In the present study we have addressed the regulation of cytosolic Ca2+ in differentiation events in the life cycle of the protozoan parasite Trypanosoma brucei. Bloodstream form (BSF) trypanosomes include the mitotically active long slender forms (LS) which differentiate to two nondividing stages--intermediate (INT) which transform into short stumpy (SS) forms. An axenic in vitro culture system was used to cultivate LS to a density greater than 1.0 x 10(6) cells/ml/day. Populations of the intermediate BSF (INT) and SS were derived from cultured LS by treatment with difluoromethyl ornithine (DFMO, 100 microM) for 2 and 4 days, respectively. A semiquantitative reverse transcriptase-coupled polymerase chain reaction protocol (SQ-RT-PCR) was developed to objectively distinguish the three BSF by monitoring the relative levels of stage-specific mRNAs--cytochrome oxidase II (COXII), variant surface glycoprotein, and procyclin during the differentiation of LS to SS, showing an increase in COXII and procyclin mRNA expression during this process of differentiation. Basal cytosolic Ca2+ levels [Ca2+]i of populations of LS, INT, and SS were studied using Indo-1 dual emission fluorometry. [Ca2+]i was maximal in dividing LS cells and was shown to decrease coincidentally with early events in the process of differentiation to INT and SS. Thapsigargin (1 microM), reported to cause the release of Ca2+ from the endoplasmic reticulum, elevated [Ca2+]i by about 30-60 nM in all BSF; however, the total thapsigargin-releasable stores decreased in parallel with the decrease in basal [Ca2+]i. Control treatments verified that elevations in [Ca2+]i in response to thapsigargin were intracellular in origin. These results may reflect the cessation of cytosolic Ca2+ transients involved in the regulation of mitosis as the parasite exits from the cell cycle and differentiates from rapidly dividing LS to the nondividing SS.
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PMID:Trypanosoma brucei: analysis of cytoplasmic Ca2+ during differentiation of bloodstream stages in vitro. 865 42

The neuron cell bodies and microvessels in sections of the nodose (vagal sensory) ganglion (NG) of Wistar rats of 4- and 24-months of age have been examined morphometrically and by quantitative enzyme histochemistry. The range of neuronal somata areas was similar at the two ages and distributed unimodally, ranging approximately from 200-1500 microns 2 with the largest somata occurring in the older age group. The range of microvessel diameters was also comparable but the largest microvessels were seen in the older animals. The histological arrangement of the ganglion permitted analyses to be made of 'neuronal' and 'axonal' areas independently. The number of microvessels per unit area was less in regions of the ganglion occupied by axons at both ages. Random transects indicated that the percentage area occupied by neuron somata decreases and that of axons increases with age. Overall, however, the results suggest that the histological organization, the size of vagal sensory neurons, the ganglionic microvessels, and the relationship between them, does not change greatly in Wistar rats of up to 2 years of age. Ultrastructural features of the aged sensory neurons included the presence of secondary lysosomes, disrupted rough endoplasmic reticulum, swollen Golgi cisternae, and the presence of much filamentous material in the perikaryon similar to that seen in chromatolytic neurons. However, analysis of electron micrographs did not reveal significant changes in the numbers of mitochondria or Golgi bodies. There was an overall increased thickness in the microvascular wall in the older animals with the endothelium and pericyte covering being significantly increased, but the thickness of the basal lamina was unchanged. The activities of neuronal NADH tetrazolium reductase, succinate dehydrogenase and cytochrome oxidase were all increased with age. The results suggest that vagal sensory neurons are not greatly affected by age in the rat.
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PMID:Neurons and microvessels of the nodose (vagal sensory) ganglion in young adult and aged rats: morphometric and enzyme histochemical studies. 885 85


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