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:1.3.5.1 (succinate dehydrogenase)
8,177 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Chlorella protothecoides cultures grown in a nitrogen-free bleaching medium (BM-N) in the dark rapidly degraded chlorophyll (Chl) to red catabolites. This degreening process was investigated under different growth conditions. Supply of nitrogen to the culture medium (BM+N) inhibited bleaching and the synthesis of catabolites as did the addition to BM-N of cycloheximide or a chelator, 2,2'-bipyridyl. In contrast, chloramphenicol or the protease inhibitor E64 had no effect. During bleaching, Chl breakdown was accompanied by the degradation of cellular proteins such as light-harvesting complex II, cytochrome f and protochlorophyllide oxido-reductase. During growth in BM-N, protease activity increased and proteins immunologically detectable with an antibody against a senescence-enhanced cysteine protease accumulated. cDNAs from BM-N and BM+N cells were used for differential and subtractive screening to isolate cDNAs representing genes with degreening-enhanced expression (dee) in C. protothecoides. Several different dees were identified with different patterns of expression during Chlorella growth but which were all expressed at higher levels during bleaching. Among these, dee4 was most abundant and its expression was exclusive in BM-N cultures. Analysis of the dee sequences showed that they encode different proteins including a novel amino acid carrier (dee4), ferritin, ATP-dependent citrate lyase, a Ca2+-binding protein, MO25, ubiquinone-cytochrome c-reductase and several new proteins.
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PMID:Chlorophyll breakdown in Chlorella protothecoides: characterization of degreening and cloning of degreening-related genes. 1079 14

Low-temperature 15N and 13C CP/MAS (cross-polarization/magic angle spinning) NMR has been used to analyze BChl-histidine interactions and the electronic structure of histidine residues in the light-harvesting complex II (LH2) of Rhodopseudomonas acidophila. The histidines were selectively labeled at both or one of the two nitrogen sites of the imidazole ring. The resonances of histidine nitrogens that are interacting with B850 BChl a have been assigned. Specific 15N labeling confirmed that it is the tau-nitrogen of histidines which is ligated to Mg2+ of B850 BChl molecules (beta-His30, alpha-His31). The pi-nitrogens of these Mg2+-bound histidines were found to be protonated and may be involved in hydrogen bond interactions. Comparison of the 2-D MAS NMR homonuclear (13C-13C) dipolar correlation spectrum of [13C6,15N3]-histidines in the LH2 complex with model systems in the solid state reveals two different classes of electronic structures from the histidines in the LH2. In terms of the 13C isotropic shifts, one corresponds to the neutral form of histidine and the other resembles a positively charged histidine species. 15N-13C double-CP/MAS NMR data provide evidence that the electronic structure of the histidines in the neutral BChl a/His complexes resembles the positive charge character form. While the Mg...15N isotropic shift confirms a partial positive charge transfer, its anisotropy is essentially of the lone pair type. This provides evidence that the hybridization structure corresponding to the neutral form of the imidazole is capable of "buffering" a significant amount of positive charge.
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PMID:Ultrahigh field MAS NMR dipolar correlation spectroscopy of the histidine residues in light-harvesting complex II from photosynthetic bacteria reveals partial internal charge transfer in the B850/His complex. 1145 90

The ultimate objective of PhIMED, in which two European (Germany, Italy) and two Mediterranean (Morocco, Egypt) countries collaborate, is to improve the cultivation of French bean (Phaseolus vulgaris) under arid and semi-arid conditions by analysing and enhancing stress tolerance of the nitrogen fixing rhizobial microsymbionts. Rhizobial strains nodulating P. vulgaris (RP strains) isolated from areas in Morocco frequently subjected to drought were analysed for their salt and pH tolerance and their phylogenetic relationship. Strain RP163, exhibiting high nodulation efficiency and a broad pH tolerance was mutagenised by Tn5 and mutants unable to grow on extreme pH media were isolated. Some of the mutants affected in low pH tolerance were found to be mutated in genes related to cobalmin biosynthesis and in succinate dehydrogenase (sdhA). In a parallel approach, promoters and genes inducible under extreme pH values were identified in Rhizobium leguminosarum bv. viciae VF39, among them gabT, which encodes the GABA transaminase and which is induced under acidic conditions. The same gene is present and similarly regulated in RP163. The actSR gene region was cloned from VF39, sequenced and mutants generated in this region were found to be impaired in growth at low pH, but also under neutral conditions. The Agrobacterium rhizogenes 'promintron' promoter, reported to be activated in stationary phase, was found to be also strongly induced under acidic conditions in rhizobia and it is currently being characterised to construct a system allowing the expression of stress tolerance genes in bacteroids and free-living bacteria.
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PMID:Characterisation of Phaseolus symbionts isolated from Mediterranean soils and analysis of genetic factors related to pH tolerance. 1156 93

Histochemical staining of alkaline phosphatase (ALP) and succinate dehydrogenase (SDH) activities in four arbuscular mycorrhizal fungi (Glomus intraradices, G. fasciculatum, G. monosporum and G. mosseae) and their relation to growth and metabolic activities of soybean plants were investigated in a greenhouse experiment. In general, mycorrhizal inoculation significantly increased the growth responses, phosphorus and nitrogen contents, acid and alkaline phosphatases as well as total soluble protein of soybean compared to non-mycorrhizal plants. Stimulation was related to the viability of each mycorrhizal fungus. The localization of succinate dehydrogenase (as a vital stain of metabolically active fungus) and alkaline phosphatase activity (as a potential marker of efficiency of the symbiosis) in the arbuscular mycorrhizal fungi were variable. The activity appeared in young arbuscles and intercellular hyphae, whereas the collapsed arbuscules were inactive. The histochemical staining results demonstrated that the activity of alkaline phosphatase fungi was lower than succinate dehydrogenase. The use of nitroblue tetrazolium chloride as a vital stain for SDH activity showed that all mycorrhizal infection revealed by trypan blue staining was not physiologically active. Thus, the possible utilization of these enzymes to assess the activity of mycorrhizal fungi and its relation with effectively for plant growth and mineral contents is discussed.
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PMID:Measurement of the viability of arbuscular-mycorrhizal fungi using three different stains; relation to growth and metabolic activities of soybean plants. 1177 Aug 54

Intracellular signal transfer in bacteria is dominated by phosphoryl transfer between conserved transmitter and receiver domains in regulatory proteins of so-called two-component systems. Escherichia coli contains 30 such systems, which allow it to modulate gene expression, enzyme activity and the direction of flagellar rotation. The authors have investigated whether, and to what extent, these separate systems form (an) interacting network(s) in vivo, focussing on interactions between four major systems, involved in the responses to the availability of phosphorylated sugars (Uhp), phosphate (Pho), nitrogen (Ntr) and oxygen (Arc). Significant cross-talk was not detectable in wild-type cells. Decreasing expression levels of succinate dehydrogenase (reporting Arc activation), upon activation of the Pho system, appeared to be independent of signalling through PhoR. Cross-talk towards NtrC did occur, however, in a ntrB deletion strain, upon joint activation of Pho, Ntr and Uhp. UhpT expression was demonstrated when cells were grown on pyruvate, through non-cognate phosphorylation of UhpA by acetyl phosphate.
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PMID:Investigation of in vivo cross-talk between key two-component systems of Escherichia coli. 1178

Malonate is a three-carbon dicarboxylic acid. It is well known as a competitive inhibitor of succinate dehydrogenase. It occurs naturally in biological systems, such as legumes and developing rat brains, which indicates that it may play an important role in symbiotic nitrogen metabolism and brain development. Recently, enzymes that are related to malonate metabolism were discovered and characterized. The genes that encode the enzymes were isolated, and the regulation of their expression was also studied. The mutant bacteria, in which the malonate-metabolizing gene was deleted, lost its primary function, symbiosis, between Rhizobium leguminosarium bv trifolii and clover. This suggests that malonate metabolism is essential in symbiotic nitrogen metabolism, at least in clover nodules. In addition to these, the genes matB and matC have been successfully used for generation of the industrial strain of Streptomyces for the production of antibiotics.
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PMID:Malonate metabolism: biochemistry, molecular biology, physiology, and industrial application. 1235 84

The present study was designed to determine if changes in function and metabolism of heart muscle induce alterations in characteristics of skeletal muscle. We investigated the histochemical and biochemical properties of soleus (SOL) and extensor digitorum longus (EDL) muscles in Wistar rats at the chronic phase after coronary artery occlusion/reperfusion. The size of myocardial infarct region was evaluated using a high resolution pinhole single photo emission computed tomography (SPECT) system. 4 wk after left coronary artery occlusion/reperfusion, the SOL and EDL of hindlimb were dissected out and immersed in isopentane cooled with liquid nitrogen for subsequent histochemical and biochemical analysis. From SPECT imaging, the blood circulation was recovered, but the recovery of fatty acid metabolism was not observed in infarct region of heart. Citrate synthase (CS) and 3-hydroxyacyl-CoA dehydrogenase (HAD) activities in infarct region of heart were lower in the myocardial infarction (MI, n = 6) group compared with that of age-matched sham-operated (Sham, n = 6) group. In addition, heart muscle hypertrophy caused by the dysfunction in MI group was observed. In skeletal muscle, the atrophy and transition of fiber type distribution in MI group, reported in previous studies of heart failure, were not observed. However, the succinate dehydrogenase (SDH) activity in the slow twitch oxidative (SO) from SOL of MI group decreased by 9.8% and in the fast twitch oxidative glycolytic fibers (FOG), 8.0% as compared with sham group. Capillary density of the SO fibers from SOL of MI group also reduced by 18.5% and in the FOG fibers, 18.2% as compared with Sham group. Decreased capillary density in this study related significantly to decreased SDH activity of single muscle fibers in chronic phase of perfusion after surgical infarction. Our results make it clear that there is a difference in the reaction of skeletal muscle to coronary artery occlusion/reperfusion compared with chronic heart failure. However, our data would support the notion that there is a linkage between the function of heart and physiological properties of skeletal muscle.
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PMID:[Adaptation in properties of skeletal muscle to coronary artery occlusion/reperfusion in rats]. 1250 Apr 16

The structure, composition, and function of membranes from organelles of mammalian spermatozoa differ from each other and from the sperm's plasma membrane. Avian sperm studies have suffered from the lack of a technique to isolate these various membranes, which the current study now provides. Nitrogen cavitation and differential centrifugation separated head plasma membranes (HPM) of rooster sperm from sperm debris, acrosomal membranes, and mitochondrial membranes and characterized these membranes enzymatically and microscopically. The HPM was enriched in acid phosphatase (marker enzyme for HPM; 1,814.81 +/- 470.43 micromol phosphate released/microg protein vs. 868.53 +/- 75.55 for whole semen; a 202.5 +/- 37.8% enrichment, mean +/- SE, P < 0.001), with less (P < 0.001) mitochondrial and acrosomal enzyme activity. The mitochondrial fraction had 515.1 +/- 167.6% more succinate dehydrogenase activity (marker for mitochondria, P < 0.001) and the acrosomal fraction had 315.4 +/- 61.2% more acetylglucosaminidase activity (marker for acrosome, P < 0.0001) than whole semen. Thin layer and gas chromatography showed that HPM lipids had more (P < 0.05) sphingomyelin and phosphatidylserine, and less phosphatidylcholine and phosphatidylethanolamine than did the sperm body membranes (SBM). Overall, HPM had less polyunsaturated fatty acids than SBM (36.8 +/- 3.4 vs. 44.5 +/- 1.7% of total phospholipids, P < 0.05). HPM had slightly more n3 (3.2 +/- 0.5 vs. 1.3 +/- 0.2%, P < 0.01) but much less n6 (33.6 +/- 3.3 vs. 43.3 +/- 1.9%, P < 0.01), specifically less C22:4n6. Future study of avian sperm will be able to reliably characterize the structure-function relationships of specific sperm membranes.
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PMID:Isolation and unique composition of purified head plasma membrane from rooster sperm. 1251 81

The utilization of some agro-industrial wastes as soil conditioners to provide free-living nitrogen-fixing bacterial populations (e.g. Azospirillum spp.) with carbon and energy sources, may be an interesting perspective for agriculture. However, the presence of ammonium nitrogen in cultivated soils and/or various wastes could inhibit the growth of the nitrogen-fixing populations. The present investigation shows that growth of Azospirillum lipoferum was restricted at a dissolved oxygen (DO) concentration equal to 135 microM, when the initial NH4Cl concentration increased from 0.5 to 0.9 g/l. The activities of both citrate synthase (CS) and isocitrate dehydrogenase were significantly decreased in the presence of 0.9 g/l NH4Cl (e.g., 40% and 66%, respectively, in cells incubated for 95 h), while ammonium assimilation occurred via the glutamate dehydrogenase reaction. Furthermore, growth limitation occurred even in the presence of 0.5 g/l NH4Cl, when the DO concentration decreased from 135 to 30 microM. The activities of both CS and succinate dehydrogenase were dramatically decreased in cells grown at the lower DO concentration (e.g., 90% and 93% respectively, in a 95 h incubation), while ammonium assimilation was limited due to the low activities of both glutamate dehydrogenase and glutamate synthase. It is concluded that the threshold of ammonium concentration at which growth of A. lipoferum is limited, depends on the DO concentration in the medium.
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PMID:Metabolic activities in Azospirillum lipoferum grown in the presence of NH4+. 1276 47

NMR isotopic filiation of 13C-labelled aspartate and glutamate was used to explore the tricarboxylic acid (TCA) pathway in Saccharomyces cerevisiae during anaerobic glucose fermentation. The assimilation of [3-13C]aspartate led to the formation of [2,3-13C]malate and [2,3-13C]succinate, with equal levels of 13C incorporation, whereas site-specific enrichment on C-2 and C-3 of succinate was detected only with [3-13C]glutamate. The non-random distribution of 13C labelling in malate and succinate demonstrates that the TCA pathway operates during yeast fermentation as both an oxidative and a reductive branch. The observed 13C distribution suggests that the succinate dehydrogenase (SDH) complex is not active during glucose fermentation. This hypothesis was tested by deleting the SDH1 gene encoding the flavoprotein subunit of the SDH complex. The growth, fermentation rate and metabolite profile of the sdh1 mutant were similar to those of the parental strain, demonstrating that SDH was indeed not active. Filiation experiments indicated the reductive branch of the TCA pathway was the main pathway for succinate production if aspartate was used as the nitrogen source, and that a surplus of succinate was produced by oxidative decarboxylation of 2-oxoglutarate if glutamate was the sole nitrogen source. Consistent with this finding, a kgd1 mutant displayed lower levels of succinate production on glutamate than on other nitrogen sources, and higher levels of oxoglutarate dehydrogenase activity were observed on glutamate. Thus, the reductive branch generating succinate via fumarate reductase operates independently of the nitrogen source. This pathway is the main source of succinate during fermentation, unless glutamate is the sole nitrogen source, in which case the oxidative decarboxylation of 2-oxoglutarate generates additional succinate.
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PMID:Investigation by 13C-NMR and tricarboxylic acid (TCA) deletion mutant analysis of pathways for succinate formation in Saccharomyces cerevisiae during anaerobic fermentation. 1294 91


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