Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.3.5.1 (succinate dehydrogenase)
 8,177 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Combined methodologies of immunohistochemistry, histochemistry and photometric image analysis were applied: (1) to characterise control equine skeletal muscle fibres according to their myosin heavy chain (MyHC) composition and (2) to determine on a fibre-to-fibre basis the correlation between contractile [i.e. MyHC(s), myofibrillar ATPase (mATPase) and sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA) isoforms], metabolic [i.e. succinate dehydrogenase (SDH) and alpha-glycerophosphate dehydrogenase (GPD) activities, glycogen and phospholamban (PLB) contents], and morphological [i.e. cross-sectional area (CSA), capillary and nuclear densities] features of individual myofibres. An accurate delineation of MyHC-based fibre types was obtained with the immunohistochemical method developed. This protocol showed a high sensitivity and objectivity to delineate hybrid fibres with overwhelming dominance of one MyHC isoform and, furthermore, it allowed a semiquantitative delineation of fast hybrid fibres according to the predominant MyHC isoform expressed. The phenotypic differences in contractile, metabolic and morphological properties seen between fibre types were related to MyHC content. Slow fibres had the lowest mATPase activity (related to shortening velocity), the highest SDH activity (oxidative capacity), the lowest GPD activity (glycolytic metabolism) and glycogen content, the smallest CSA, the greatest capillary and nuclear densities, and expressed slow SERCA isoform and PLB, but not the fast SERCA isoform. The reverse pattern was true for pure IID/X fibres, and type IIA fibres had intermediate properties. Hybrid IIAD/X fibres had mean values intermediate to those of their respective pure phenotypes. Discrimination of fibres according to their MyHC content was possible on the basis of their contractile and non-contractile profiles. These intrafibre interdependencies suggest that, even when controlled by different mechanisms, myofibres of control horses exhibit a high degree of co-ordination in their physiological, biochemical and anatomical features.
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PMID:Co-ordinated expression of contractile and non-contractile features of control equine muscle fibre types characterised by immunostaining of myosin heavy chains. 1170 88

Nitric oxide synthase-1 (NOS-1) is found in high concentrations in skeletal muscles, where its synthesis product nitric oxide (NO) is reported to be involved in a number of processes, including the modulation of the oxidative metabolism of myofibers. Performing immunoblot analysis and quantification of formazan produced by its specific NADPH diaphorase activity, we found NOS-1 to be enriched in rat skeletal muscles with a high proportion of fast-twitch myofibers. Since these myofibers represent a metabolically heterogeneous subpopulation, we extended our investigation to the level of individual myofibers. Using serial sections we combined myosin heavy chain-based fiber-typing with quantitative succinate dehydrogenase histochemistry to determine three groups of fiber-types, comprising fast-oxidative, fast-glycolytic and slow-oxidative myofibers. Image analysis showed that NOS-1 diaphorase activity is significantly enriched in fast-oxidative myofibers compared with fast-glycolytic and slow-oxidative ones. In order to characterize potential biological effects of the fiber-type-specific enrichment of NOS-1, we performed cytochrome oxidase histochemistry in the presence of the NO donors NOC-9 and SNAP. Both NO donors reduced cytochrome oxidase activity in all myofibers investigated with almost identical semi-maximal inhibition rates, although fast-oxidative and slow-oxidative myofibers contained twice as much basal catalytic activity than fast-glycolytic ones. In summary, we suggest that the NOS-1/NO system of skeletal muscles exerts its biological role especially in fast-oxidative myofibers, since these myofibers express more NOS-1 than fast-glycolytic or slow-oxidative ones and also contain the highest concentrations of cytochrome oxidases as potential target molecules of NO.
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PMID:Nitric oxide synthase-1 is enriched in fast-twitch oxidative myofibers. 1170 44

The role of mitochondrial proteins as antigens to antibodies of anti-M7 sera was analysed by flavin fluorescence, one- and two-dimensional Western blots and blue native gel electrophoresis. Flavin fluorescence of succinate dehydrogenase (SucDH, complex II of the respiratory chain) of rat liver inner mitochondrial membranes correlated with the immunoreactivity of a representative anti-M7 myocarditis serum. Antigens of isolated bovine heart mitochondria reacting with antibodies of myocarditis serum on two-dimensional Western blots were identified by MALDI-TOF and NanoESI mass spectrometry as myosin heavy chain beta and as dihydrolipoamide dehydrogenase of the mitochondrial 2-oxoacid dehydrogenase complexes. The SucDH-flavoprotein was not resolved as a discrete protein spot on two-dimensional polyacrylamide gels. However, separation of the rat liver inner mitochondrial membrane complexes by blue native gel electrophoresis followed by Western blotting, and Western blots of purified Escherichia coli SucDH complex revealed that anti-M7 sera contained antibodies directed against the SucDH-flavoprotein subunit.
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PMID:Analysis of mitochondrial antigens reveals inner membrane succinate dehydrogenase flavoprotein subunit as autoantigen to antibodies in anti-M7 sera. 1198 94

The purpose of this study was to determine whether induced expression of the Ca2+ buffering protein parvalbumin (PV) in slow-twitch fibres would lead to alterations in physiological, biochemical and molecular properties reflective of a fast fibre phenotype. Transgenic (TG) mice were generated that overexpressed PV in slow (type I) muscle fibres. In soleus muscle (SOL; 58 % type I fibres) total PV expression was 2- to 6-fold higher in TG compared to wild-type (WT) mice. Maximum twitch and tetanic tensions were similar in WT and TG but force at subtetanic frequencies (30 and 50 Hz) was reduced in TG SOL. Twitch time-to-peak tension and half-relaxation time were significantly decreased in TG SOL (time-to-peak tension: 39.3 +/- 2.6 vs. 55.1 +/- 4.7 ms; half-relaxation time: 42.1 +/- 3.5 vs. 68.1 +/- 9.6 ms, P < 0.05 for TG vs. WT, respectively; n = 8-10). There was a significant increase in expression of type IIa myosin heavy chain (MHC) and ryanodine receptor at the mRNA level in TG SOL but there were no differences in MHC expression at the protein level and thus no difference in fibre type. Whole muscle succinate dehydrogenase activity was reduced by 12 +/- 0.4 % in TG SOL and single fibre glycerol-3-phosphate dehydrogenase activity was decreased in a subset of type IIa fibres. These differences were associated with a 64 % reduction in calcineurin activity in TG SOL. These data show that overexpression of PV, resulting in decreased calcineurin activity, can alter the functional and metabolic profile of muscle and influence the expression of key marker genes in a predominantly slow-twitch muscle with minimal effects on the expression of muscle contractile proteins.
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PMID:Alterations in slow-twitch muscle phenotype in transgenic mice overexpressing the Ca2+ buffering protein parvalbumin. 1256 45

Muscle is a permanent tissue, and in the adult pronounced changes can occur in pre-existing fibres without the formation of new fibres. Thus, the mechanisms responsible for phenotype transformation in the adult might be distinct from mechanisms regulating muscle differentiation during muscle formation and growth. Myogenin is a muscle-specific, basic helix-loop-helix transcription factor that is important during early muscle differentiation. It is also expressed in the adult, where its role is unknown. In this study we have overexpressed myogenin in glycolytic fibres of normal adult mice by electroporation and single-cell intracellular injection of expression vectors. Myogenin had no effects on myosin heavy chain fibre type, but induced a considerable increase in succinate dehydrogenase and NADH dehydrogenase activity, with some type IIb fibres reaching the levels observed histochemically in normal type IIx and IIa fibres. mRNA levels for malate dehydrogenase were similarly altered. The size of the fibres overexpressing myogenin was reduced by 30-50 %. Thus, the transfected fibres acquired a phenotype reminiscent of the phenotype obtained by endurance training in man and other animals, with a higher oxidative capacity and smaller size. We conclude that myogenin can alter pre-existing glycolytic fibres in the intact adult animal.
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PMID:Myogenin induces higher oxidative capacity in pre-existing mouse muscle fibres after somatic DNA transfer. 1259 90

A spinal cord injury usually leads to an increase in contractile speed and fatigability of the paralysed quadriceps muscles, which is probably due to an increased expression of fast myosin heavy chain (MHC) isoforms and reduced oxidative capacity. Sometimes, however, fatigue resistance is maintained in these muscles and also contractile speed is slower than expected. To obtain a better understanding of the diversity of these quadriceps muscles and to determine the effects of training on characteristics of paralysed muscles, fibre characteristics and whole muscle function were assessed in six subjects with spinal cord lesions before and after a 12-week period of daily low-frequency electrical stimulation. Relatively high levels of MHC type I were found in three subjects and this corresponded with a high degree of fusion in 10-Hz force responses (r=0.88). Fatigability was related to the activity of succinate dehydrogenase (SDH) (r=0.79). Furthermore, some differentiation between fibre types in terms of metabolic properties were present, with type I fibres expressing the highest levels of SDH and lowest levels of alpha-glycerophosphate dehydrogenase. After training, SDH activity increased by 76+/-26% but fibre diameter and MHC expression remained unchanged. The results indicate that expression of contractile proteins and metabolic properties seem to underlie the relatively normal functional muscle characteristics observed in some paralysed muscles. Furthermore, training-induced changes in fatigue resistance seem to arise, in part, from an improved oxidative capacity.
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PMID:Variability in fibre properties in paralysed human quadriceps muscles and effects of training. 1263 95

To determine whether long-term reductions in neuromuscular activity result in alterations in metabolic capacity, the activities of oxidative, i.e., succinate dehydrogenase (SDH) and citrate synthase (CS), and glycolytic, i.e., alpha-glycerophosphate dehydrogenase (GPD), enzyme markers were quantified in rat soleus muscles 1, 3, and 6 mo after a complete spinal cord transection (ST). In addition, the proportional content of lactate dehydrogenase (LDH) isozymes was used as a marker for oxidative and glycolytic capacities. The myosin heavy chain (MHC) isoform content of a fiber served as a marker of phenotype. In general, MHC isoforms shifted from MHC1 toward MHC2, particularly MHC2x, after ST. Mean SDH and CS activities were higher in ST than control at all time points. The elevated SDH and CS activities were indicative of an enhanced oxidative capacity. GPD activities were higher in ST than control rats at all time points. The increase in activity of SDH was larger than GPD. Thus the GPD-to-SDH (glycolytic-to-oxidative) ratio was decreased after ST. Compared with controls, total LDH activity increased transiently, and the LDH isozyme profile shifted from LDH-1 toward LDH-5, indicative of an enhanced glycolytic capacity. Combined, these results indicate that 1) the metabolic capacities of soleus fibers were not compromised, but the interrelationships among oxidative and glycolytic capacity and MHC content were apparently dissociated after ST; 2) enhancements in oxidative and glycolytic enzyme activities are not mutually exclusive; and 3) chronic reductions in skeletal muscle activity do not necessarily result in a reduced oxidative capacity.
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PMID:Adaptations in metabolic capacity of rat soleus after paralysis. 1456 62

We hypothesize that high intensity training for Thoroughbred horses that have been subjected to conventional training could further improve the metabolic properties of the middle gluteal muscle. Nine well-trained horses were subjected to high intensity (80-100% Vdot;O(2)max, 5 minx2) training for 12 weeks. Biopsy samples were obtained from the muscle before and after 4 and 12 weeks of training. Three of the 9 horses did not complete the training programme. In the remaining 6 horses, activities of succinic dehydrogenase (SDH), phosphofructokinase (PFK) and 3-hydroxy acyl CoA dehydrogenase (HAD), and the composition of myosin heavy chain isoforms were analyzed by biochemical techniques. After 12 weeks of training, a significant increase was found in PFK activity but not in the SDH and HAD activities. There were no significant changes in the composition of myosin heavy chain isoforms. The high intensity training in this study was effective at increasing glycolytic enzyme activity, indicating the possibility to improve anaerobic capacity, which potentially could contribute greatly to performance in Thoroughbred horses. This study also highlighted a fact that high intensity training should be given with the great care to prevent the skeletal muscle injuries.
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PMID:Effect of high intensity training on anaerobic capacity of middle gluteal muscle in Thoroughbred horses. 1467 57

Myostatin (Mstn) is a member of the transforming growth factor-beta family that negatively regulates skeletal muscle mass. Mstn knockout mice have greater skeletal muscle mass than wild-type littermates. We investigated the effect of Mstn on fiber type by comparing adult muscles from the murine Mstn knockout with wild-type controls. Based on myofibrillar ATPase staining, the soleus of Mstn knockout mice displays a larger proportion of fast type II fibers and a reduced proportion of slow type I fibers compared with wild-type animals. Based on staining for succinate dehydrogenase (SDH) activity, a larger proportion of glycolytic fibers and a reduced proportion of oxidative fibers occur in the extensor digitorum longus (EDL) of Mstn knockouts. These differences in distribution of fiber types are accompanied by differences in the expression of myosin heavy chain (MHC) isoforms. In both Mstn knockout soleus and EDL, larger numbers of faster MHC isoforms are expressed at the expense of slower isoforms when compared with wild-type littermates. Thus, the absence of Mstn in the knockout mouse leads to an overall faster and more glycolytic muscle phenotype. This muscle phenotype is likely a consequence of developmental processes, and inhibition of Mstn in adults does not cause a transformation to a more fast and glycolytic phenotype. Our findings suggest that myostatin has a critical role in regulating the formation, proliferation, or differentiation of fetal myoblasts and postnatal fibers.
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PMID:Loss of myostatin expression alters fiber-type distribution and expression of myosin heavy chain isoforms in slow- and fast-type skeletal muscle. 1546 12

The potential of two interventions, alone or in combination, to restore chronic spinal cord transection-induced changes in skeletal muscles of adult Sprague-Dawley rats was studied. Hind limb skeletal muscles were examined in the following groups of animals: rats with a complete spinal cord transection (Tx) for 8 weeks; Tx with a 4-week delay before initiation of a 4-week motor-assisted cycling exercise (Ex) program; Tx with a 4-week delay before transplantation (Tp) of fetal spinal cord tissue into the lesion cavity; Tx with a 4-week delay before Tp and Ex; and uninjured control animals. Muscle mass, muscle to body mass ratios, and mean myofiber cross-sectional areas were significantly reduced 8 weeks after transection. Whereas transplantation of fetal spinal cord tissue did not reverse this atrophy and exercise alone had only a modest effect in restoring lost muscle mass, the combination of exercise and transplantation significantly increased muscle mass, muscle to body mass ratios, and mean myofiber cross-sectional areas in both soleus and plantaris muscles. Spinal cord injury (SCI) also caused changes in myosin heavy chain (MyHC) expression toward faster isoforms in both soleus and plantaris and increased soleus myofiber succinate dehydrogenase (SDH) activity. Combined exercise and transplantation led to a change in the expression of the fastest MyHC isoform in soleus but had no effect in the plantaris. Exercise alone and in combination with transplantation reduced SDH activity to control levels in the soleus. These results suggest a synergistic action of exercise and transplantation of fetal spinal cord tissue on skeletal muscle properties following SCI, even after an extended post-injury period before intervention.
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PMID:Cycling exercise and fetal spinal cord transplantation act synergistically on atrophied muscle following chronic spinal cord injury in rats. 1547 Aug 19


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