Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:Q8NEX9 (reductase)
 26,410 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Muscle tissue samples were obtained from vastus lateralis muscle of elite weight/power lifters (WL/PL, n = 8), endurance athletes (EA, n = 8), and nonathletes (NA, n = 8). Histochemical stainings for myofibrillar ATPase, NADH-tetrazolium reductase, and amylase-periodic acid-Schiff, respectively, were undertaken to assess relative distribution of fast-twitch (FT) and slow-twitch (ST) muscle fiber types, fiber size, and capillary supply [capillaries per fiber (cap X fib-1) and capillaries per mm2 (cap X mm-2)]. Fiber type distribution in WL/PL, EA, and NA averaged 59 +/- 6 (SD), 40 +/- 11, and 61 +/- 10% FT. Values for mean fiber area and FT/ST area were significantly greater in WL/PL compared with values obtained in EA and NA. Similar values for cap X fib-1 were observed WL/PL (2.06 +/- 0.74) and NA (2.16 +/- 0.34). EA exhibited greater cap X fib-1 (3.11 +/- 0.73) than WL/PL (NS) and NA (P less than 0.01). However, cap X mm-2 in WL/PL (199 +/- 29) was lower than in EA (401 +/- 61, P less than 0.001) and NA (306 +/- 29, P less than 0.01). It is suggested that heavy resistance training in contrast to endurance training does not result in increased capillary density. Instead, as a consequence of fiber hypertrophy induced by muscle overloading, capillary density is decreased.
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PMID:Muscle capillary supply and fiber type characteristics in weight and power lifters. 669 33

The temperature dependence of various activities related to the energy metabolism of isolated membranes and whole cells of the thermophilic bacterium Chloroflexus aurantiacus was determined after phototrophic growth at either 40, 50, or 60 degrees C. The data obtained were expressed by use of Arrhenius plots. Maximum activities were determined at about 65 degrees C for succinate 2,4-dichlorophenol-indophenol reductase as well as NADH oxidase and at about 70 degrees C for Mg-ATPase and for light-induced proton extrusion by cells. Activation energies for Mg-ATPase and light-induced proton extrusion were about 40 kJ mol-1 from 30 degrees C to about 50 degrees C and they increased significantly at higher temperatures. Essentially the same dependency was detectable with NADH oxidase, except for an increase in activation energy below 41 degrees C. All of these responses were independent of growth temperature. Succinate-2,4-dichlorophenol-indophenol reductase showed a change in activation energy around 41 degrees C only with cells grown at 60 degrees C. Differences in the responses of cells grown at different temperatures were identified on the basis of changes from sigmoidal to hyperbolic kinetics for light saturation of proton extrusion. Moreover, the thermostability of proton extrusion was maximal when assayed at the corresponding growth temperatures. In any case, thermostability was lowest at the 65 and 68 degrees C assay temperatures. Differential scanning calorimetry with membranes revealed irreversible heat uptake from about 60 to 72 degrees C. The results are discussed in light of the activation energy for the specific growth rate, which is lowest at temperatures from 40 degrees C to the optimum at 60 degrees C.
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PMID:Temperature dependence of growth and membrane-bound activities of Chloroflexus aurantiacus energy metabolism. 686 22

The purpose of the present study was to investigate the structure of muscle mitochondria for a possible early response to electrically induced short- and medium-term activity. Rats were anesthetized with Na-pentobarbital. Both parts of the triceps surae muscle were stimulated by direct electrical impulses for periods between 2 and 60 min. Biopsies were taken and prepared for histological, enzyme-histochemical, and electron-microscopic examinations. Enzyme histochemistry demonstrated an increase of oxidative activity and an increase of RNA by NADH-tetrazolium reductase and modified Gomori's trichrome staining or acridine orange-induced fluorescence, respectively. These changes appeared especially within type I fibers, as shown by ATPase reactions, and corresponded to an increase in number and size of muscle mitochondria, followed by alterations of the mitochondrial structure. The mitochondria reacted immediately to the electrical stimulation of the muscle, and the degree of alteration depended on the duration of the experiments. These results suggest that mitochondria have a certain capacity for adapting rapidly to changes in the energy metabolism. Beginning energetic decompensation may be responsible for the alterations of the mitochondrial structure.
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PMID:Mitochondrial reaction in skeletal muscle to induced activity. 687 72

1. Lantana intoxication of guinea-pig caused a decrease in hepatic microsomal protein content, the phospholipid: protein ratio, and the cholesterol: protein ratio. 2. Activities of aniline hydroxylase, aminopyrine N-demethylase, NADH-cytochrome c reductase, NADH-ferricyanide reductase, UDP-glucuronosyl transferase, cytochrome P-450 and glucose 6-phosphatase were decreased. 3. Activities of Mg2+ -ATPase and Na+ -K+ -ATPase were increased. However, activities of 5-nucleotides and NADPH-cytochrome c reductase were unaffected. 4. The liver endoplasmic reticulum is an important target organelle during lantana poisoning of guinea-pigs.
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PMID:Biochemical changes in hepatic microsomes of guinea-pig under lantana toxicity. 711 63

Skeletal muscle and fibroblast biopsies obtained from a normal dog and an old English sheep dog with exertional myopathy and lactic acidosis were examined for mitochondrial enzyme activities and mitochondrially coded mRNAs. The fibroblast cultures of the affected dog showed reduced cytochrome c oxidase (COX) I+II mRNA content (25% of control) and COX enzyme activities (23% of control). The skeletal muscle of the affected dog was similarly affected and showed not only decreased COX I+II mRNA content, but also decreased ATPase6 mRNA level. Apart from COX enzyme activity (62% of control), the oligomycin sensitive ATPase and NADH-Ferricyanide reductase activities were also reduced in the skeletal muscle of the affected dog (12-20% of control). These results suggest that a mitochondrial dysfunction may be the causative factor of the exertional metabolic myopathy with lactic acidosis in this affected old English sheep dog. These animals may serve as an excellent model for mitochondrial myopathies.
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PMID:Canine mitochondrial myopathy associated with reduced mitochondrial mRNA and altered cytochrome c oxidase activities in fibroblasts and skeletal muscle. 753 Jan 57

The ars (arsenical resistance) operon cloned from R-factor R773 has five genes that encode two repressor proteins, ArsR and ArsD, and three structural proteins, ArsA, ArsB, and ArsC. The ArsA and ArsB proteins form a membrane-bound pump that functions as an oxyanion-translocating ATPase. The substrates of the pump are the oxyanions arsenite or antimonite. The ArsC protein is an arsenate reductase that reduces arsenate to arsenite, which is subsequently pumped out of the cell. This review deals with the mechanism of transcriptional regulation by the ArsR repressor and allosteric regulation of the ArsA protein, the catalytic subunit of the pump. The chemical nature of the inducer plays an important role in regulation. In solution arsenite or antimonite exist as oxyanions and reacts with the cysteines in proteins. In both transcriptional regulation by the ArsR repressor and allosteric regulation of the ArsA ATPase, the ability of As(III) and Sb(III) to interact with the cysteines of the proteins, involves their action as effector.
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PMID:Mechanisms of metalloregulation of an anion-translocating ATPase. 762 56

1. The goal of this study was to characterize the fatigability, contractile relaxation properties, electrophysiological responses, and histochemical properties of the human paralyzed soleus muscle to determine its relative plasticity. 2. Acute (< 6 wk, n = 3) and chronic (> 1 yr, n = 10) paralyzed individuals had the tibial nerve activated with a 20-Hz square wave delivered for 330 ms every second for 4 min. The soleus muscle peak torque, one-half relaxation time (1/2RT), normalized maximum rate of relaxation (nMRR), and mass muscle action-potential amplitude (M wave) were computed every 30 s. A soleus muscle biopsy was evaluated for myosin adenosine triphosphatase enzyme (ATPase; pH 9.4, 4.6, and 4.2) and nicotinamide adenine dinucleotide tetrazolium reductase (NADH-TR). 3. In the chronically paralyzed group the torque was significantly reduced within 30 s of the fatigue protocol. The 1/2RT and nMRR were also significantly changed within 30 s, supporting that muscle relaxation was prolonged. No significant changes were present at comparable times during the same 4-min fatigue protocol applied to the acutely paralyzed soleus muscle. M-wave amplitude was significantly reduced in the chronic group, but only at 3 min of the fatigue protocol. Conversely, no significant changes occurred to the M waves of the acute group. 4. The correlation was high between torque and nMRR (r = 0.88-0.97) and torque and 1/2RT (r = 0.88-0.96) for each chronic subject. A close association was also found between 1/2RT and nMRR (r = 0.88-0.92) for each chronic subject. Because these variables changed minimally in the acutely paralyzed group, a lower correlation was present (r = 0.45-0.52). 5. Torque was weakly correlated to M-wave amplitude (r = 0.55) for the chronically paralyzed group. The greatest change in torque occurred at a time (0-65 s) when the least amount of change occurred in the M-wave amplitude, suggesting that the source of fatigue was within the contractile mechanism and not attributable to neuromuscular transmission compromise. 6. Despite a close association between torque and relaxation properties during fatigue of the chronically paralyzed soleus muscle, there was a significant dissociation after 5 min of recovery. Torque recovered to 60%, whereas the relaxation properties were consistently fully recovered. This suggests that the mechanism causing torque reduction covaried with the mechanism leading to prolonged relaxation during fatigue, but during recovery the two mechanisms no longer covaried. M-wave amplitude was also completely recovered at 5 min despite continued torque depression.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Fatigability, relaxation properties, and electromyographic responses of the human paralyzed soleus muscle. 766 32

Muscle cell fiber types in gracilis, rectus femoris, and long head of triceps brachii muscles of ferrets and dogs were identified on serial sections stained for myosin ATPase after preincubation at pH values of 9.8, 4.6, and 4.3 and for NADH-tetrazolium reductase (NADH-TR) activity. Although fiber types I and II were identified, the ATPase stain did not demonstrate classic type IIA/IIB fiber differences in either species. However, two type II fiber subtypes could be distinguished in the ferret because they differed slightly in staining intensity with ATPase at pH 4.3 and markedly with NADH-TR. One ferret type II fiber (designated II dark or IID) was smaller, slightly darker on ATPase, more oxidative on NADH-TR, and comprised more muscle volume than the other type II fiber (designated II light IIL). The IID fibers of ferret may represent the IID/X fibers of other authors. Both ferret type II fiber subtypes stained darker at pH 4.3 than canine II fibers. The NADH-TR staining indicated high oxidative activity in canine and ferret type I fibers. In contrast, type II fibers in the dog and IIL fibers in the ferret were moderately oxidative. Canine type IIC fibers were intermediate between type I and type II, whereas in the ferret, type IIC fibers were highly oxidative, as were type IID fibers. Ferret muscles are more oxidative than canine muscles according to NADH-TR staining. Also, ferret muscles possess 40-100% higher citrate synthase activity as compared to canine muscles.
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PMID:Comparison of muscle cell fiber types and oxidative capacity in gracilis, rectus femoris, and triceps brachii muscles in the ferret (Mustela putorius furo) and the domestic dog (Canis familiaris). 769 Oct 36

The effects of dietary supplementation with eicosapentaenoic acid (EPA) on ventricular arrhythmias during myocardial infarction were examined in a canine model. EPA was incorporated into cellular membranes after ingestion of EPA-ester (100 mg/kg body weight/day) for 8 weeks. The ratio of EPA to arachidonic acid (AA) in platelet cell membranes and myocardial microsomes was significantly increased (7% to 37% in platelet cell membranes; p < 0.01, 3% to 12% in non-infarcted cardiac microsomes; p < 0.01, and from 2% to 8% in infarcted cardiac microsomes; p < 0.01). Dietary supplementation with EPA significantly reduced the incidence and severity of arrhythmias during coronary artery occlusion. Immediately after coronary artery occlusion, all of the animals in the control group that were given a toxic dose of digitalis developed ventricular tachycardia (VT) or ventricular fibrillation (Vf), whereas none of the animals in the EPA-supplement group developed VT or Vf within 15 min after administration of digitalis. Regardless of the presence of an infarcted area, the specific activity of the Ca(2+)-pump enzyme ((Ca(2+)-Mg2+)-ATPase) within the myocardial microsomal fraction of the EPA-supplemented group was significantly higher than in that of the control group (Vmax: 140.5 +/- 19.1 vs 94.8 +/- 28.9 nmol/mg/min in non-infarcted cardiac microsomes, p < 0.01, 130.9 +/- 18.4 vs 90.2 +/- 26.4 nmol/mg/min in infarcted cardiac microsomes, p < 0.01, EPA vs control group, respectively). The specific activities of the Na(+)-pump enzyme ((Na(+)-K+)-ATPase) and NADPH-dependent cytochrome C reductase in infarcted and non-infarcted cardiac microsomes did not differ between these groups. These results indicate that EPA supplementation increases the (Ca(2+)-Mg2+)-ATPase activity within myocardial membranes that is involved in Ca2+ metabolism in myocardial cells by increasing the ratio of EPA to AA within cellular membranes. These cellular alterations are likely to reduce the severity of ventricular arrhythmias by inhibiting the rapid accumulation of intracellular Ca2+ following ischemia.
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PMID:Antiarrhythmic effects of eicosapentaenoic acid during myocardial infarction--enhanced cardiac microsomal (Ca(2+)-Mg2+)-ATPase activity. 769 37

Infection of golden hamsters with Ancylostoma ceylanicum caused significant decrease in body weight, liver weight and the protein content of liver plasma membrane. Significant inhibition of liver plasma membrane enzymes activities-5'Nucleotidase, gamma-glutamyl transpeptidase, NADHK3Fe (CN)6 reductase, Na+/K(+)-ATPase, CA(2+)-ATPase and Mg(2+)-ATPase was observed in infected animals compared to corresponding controls. Sialic acid content and phospholipid/cholesterol ratio in liver plasma membrane of the infected group were significantly reduced. The study suggests that changes in both the structural and functional organization of membrane may be a biochemical basis of the hepatotoxic effects.
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PMID:Liver plasma membrane-bound enzymes and lipids in golden hamsters infected with Ancylostoma ceylanicum. 791 86


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