Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.4.3.11 (glutamate dehydrogenase)
 4,437 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of toluene on Escherichia coli has been examined. In the presence of Mg2+, toluene removes very little protein, phospholipid, or lipopolysacharide from E. coli. In the absence of Mg2+, or in the presence of EDTA, toluene removes considerably more cell material, including several specific cytoplasmic proteins such as malate dehydrogenase (EC 1.1.1.37). In contrast, glucose-6-phosphate dehydrogenase (EC 1.1.1.49) and glutamate dehydrogenase (EC 1.4.1.4) are not released at all under the same conditions. Cells treated with toluene in the presence of Mg2+ remain relatively impermeable to pyridne nucleotides, while cells treated with toluene in the presence of EDTA become permeable to these compounds. Freeze-fracture electron microscopy shows that toluene causes considerable damage to the cytoplasmic membrane, while the outer membrane remains relatively intact. These results indicate that the permeability characteristics of toluene-treated cells depend at least partly on the state of the outer membrane after the toluene treatment.
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PMID:The effect of toluene on the structure and permeability of the outer and cytoplasmic membranes of Escherichia coli. 41 78

The realtionship between growth rate and the metabolic activity of certain liver enzymes was studied using two strains of White Plymouth Rock chickens which had been selected in divergent directions for eight-week body weight. The activities of hexokinase, glucokinase, phosphofructokinase, glucose-6-phosphate dehydrogenase, citrate synthase, glycogen synthetase, glutamate dehydrogenase and aspartate transaminase were measured at 4, 8 and 20 weeks of age. The mean percentage rate of growth of the birds selected for high eight-week body weight exceeded that of the birds selected for low eight-week body weight only during the early growth period. Thereafter, and until sexual maturity, the low-line birds grew at a faster rate, relative to body size. The mature body weight of the high-line birds exceeded that of the low-line birds by a factor of approximately 1.5. A close similarity was noted between the metabolic activity of certain liver enzymes and the growth rate (relative to body size) of the birds studied. At four and eight weeks of age, the faster-growing birds (whether high- or low-line) generally exhibited a greater capacity for glucose phosphorylation and glycolysis, but a poorer capacity for glycogen synthesis, than the slower-growing birds. At twenty weeks, growth rate and metabolic activity were similar in both strains.
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PMID:Activity of certain liver enzymes in fast- and slow-growing lines of chickens. 118 17

Freeze-substituted rat liver embedded in glycol methacrylate (GMA) has been used to demonstrate the activities of several enzymes. The following enzymes could be detected in GMA-sections by the indicated histochemical procedure(s): 5'-nucleotidase (lead salt, cerium-diaminobenzidine), alkaline phosphatase (indoxyl-tetrazolium salt), catalase (diaminobenzidine), acid phosphatase (diazonium salt), lactate dehydrogenase (tetrazolium salt) and glutamate dehydrogenase (tetrazolium salt). The activities of all these enzymes were dramatically decreased compared with the activities demonstrated in unfixed cryostat sections, with the exception of catalase. The activities of the following enzymes could not be detected in GMA-sections: glucose-6-phosphate dehydrogenase (tetrazolium salt), xanthine oxidoreductase (tetrazolium salt), D-amino acid oxidase (cerium-diaminobenzidine-cobalt-hydrogen peroxide) and glucose-6-phosphatase (cerium-diaminobenzidine). The possible role of restricted penetration of reagents into the resin was studied by measuring cytophotometrically the enzyme activities in GMA-sections of 3 and 6 microns in thickness. For all the enzymes that could be detected, the 6 microns:3 microns ratio varied from 1.4 to 2.7. An eventual retarded penetration of reagents into the resin was investigated by measuring cytophotometrically the amount of final reaction product during incubation for acid phosphatase and glutamate dehydrogenase activities. In both cases linear relationships without a lag phase were found for the specific enzyme activities with incubation time. Chemical denaturation of proteins or masking of active sites in proteins due to embedding in the resin monomer may be considered to be the main cause of decreased enzyme activities.
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PMID:Quantitative aspects of enzyme histochemistry on sections of freeze-substituted glycol methacrylate-embedded rat liver. 827 44

The metabolic cross-talk associated with re-assimilation of photorespiratory NH4+ was analysed in transformed tobacco (Nicotiana tabacum L.) plants with low activities of ferredoxin-dependent glutamine-alpha-ketoglutarate aminotransferase (Fd-GOGAT; EC 1.4.7.1). Amounts of ribulose-1,5-bisphosphate carboxylase-oxygenase (Rubisco; EC 4.1.1.39) protein and Rubisco transcripts were similar in all lines whether photorespiration rates were low (4,000 microl l(-1) CO2) or high (air). Leaf sucrose, hexose and starch contents were similar in all lines. In contrast, there was evidence that anaplerotic carbon flow was stimulated in the transformed lines with less than 60% Fd-GOGAT, since phospho enolpyruvate carboxylase (PEPc) activity and (PEPc) protein were increased. A strong positive correlation between leaf PEPc activity and glutamine accumulation was observed, suggesting that the increase in PEPc was related to the accumulation of glutamine. A modest stimulation of total NADP-isocitrate dehydrogenase (ICDH; EC 1.1.1.42) activity was also observed in the transformed lines with less than 60% Fd-GOGAT. This was accompanied by increases in both the cytosolic ICDH and mitochondrial NAD-isocitrate dehydrogenases (IDH; EC 1.1.1.41). IDH protein was also increased in the transformed plants with low Fd-GOGAT, suggesting that both IDH and ICDH are involved in the production of carbon skeletons (and ultimately alpha-ketoglutarate) necessary for the re-assimilation of NH4+. In contrast, PEPc, ICDH and IDH transcripts were similar in all lines. The aminating (but not the de-aminating) activity of NAD(H)-glutamate dehydrogenase (NAD(H)-GDH; EC 1.4.1.2) was greatly increased in plants with less than 60% of Fd-GOGAT after transfer to air. The data confirm that NH4+ or glutamine are involved in signalling, leading to modified gene expression and enzyme activity required for enhanced production of the C skeletons, to accommodate increases in the assimilation of photorespiratory NH4+. In addition, we provide the first demonstration of a compensatory role for NAD(H)-GDH in stabilising the leaf glutamic acid pool when Fd-GOGAT becomes limiting.
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PMID:Photorespiration-dependent increases in phospho enolpyruvate carboxylase, isocitrate dehydrogenase and glutamate dehydrogenase in transformed tobacco plants deficient in ferredoxin-dependent glutamine-alpha-ketoglutarate aminotransferase. 1194 64

The effect of various day temperatures on NADH-nitrate reductase, NADH- and NADPH-glutamate dehydrogenases, nitrate, protein and leaf area, measured at intervals during the ontogeny of the first trifoliolate soybean leaf, was determined. At 32.5 C and 25 C, nitrate concentration, nitrate reductase, and NADPH-glutamate dehydrogenase activities increased concurrently with leaf development and then decreased as leaf maturation progressed. At 40 C, these three components showed no initial increase and the concentration or activities decreased throughout the development of the leaf. The effects of temperature on NADH-glutamate dehydrogenase were the reverse. Rates of protein accumulation were higher at 40 C during the first 2 days of leaf development while higher rates were measured the first 5 days of leaf growth at 32.5 C. At 25 C, protein accumulation was low during the first 3 days of leaf growth, increased in the period of 3 to 5 days, and then declined up to 8 days of leaf development. Leaf expansion progressed at faster rates at 32.5 C and 25 C and at a much slower rate at 40 C. Leaf growth was essentially complete after the fifth day regardless of temperature.In crude leaf homogenates, apparent irreversible inactivation temperatures were 36 C for nitrate reductase and 65 C for NADPH-glutamate dehydrogenase. In vivo studies indicated a lower inactivation temperature for NADPH-glutamate dehydrogenase; however, it was still more heat-tolerant than nitrate reductase.We envisaged that reduced nitrogen supplied by NO(3) (-) assimilation is a factor in leaf expansion.
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PMID:Influence of Temperature on Nitrate Metabolism and Leaf Expansion in Soybean (Glycine max L. Merr.) Seedlings. 1665 11

The metabolism of vegetative organs in plants changes during the development of the reproductive organs. The regulation of this metabolism is important in the control of crop productivity. However, the complexity of the regulatory systems makes it difficult to elucidate their mechanisms. To examine these mechanisms, we constructed model experiments using Arabidopsis to analyze metabolic and gene expression changes during leaf-stage progression and after removal of the reproductive organs. Leaf gene expression levels and content of major amino acids, both of which decreased during leaf-stage progression, increased after removal of the reproductive organs. In particular, the levels of expression of cytokinin biosynthesis genes and cytokinin-responsive genes and the cytokinin content increased after removal of the reproductive organs. Analysis of plants with knockout of a cytokinin-biosynthetic gene (AtIPT3) and a cytokinin receptor gene (AHK3) indicated that glutamate dehydrogenase genes (GDH3) were regulated by cytokinin signaling. These data suggest that cytokinins regulate communication between reproductive and vegetative organs, and that GDH3 is one target of the cytokinin-mediated regulation of nitrogen metabolism.
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PMID:Reproductive organs regulate leaf nitrogen metabolism mediated by cytokinin signal. 1904 87

Boron (B) toxicity has become important in areas close to the Mediterranean Sea where intensive agriculture has been developed. The objective of this research was to study the effects of B toxicity (0.5 mM and 2.0 mM B) on nitrogen (N) assimilation of two tomato cultivars that are often used in these areas. Leaf biomass, relative leaf growth rate (RGR(L)), concentration of B, nitrate (NO(3) (-)), ammonium (NH(4) (+)), organic N, amino acids and soluble proteins, as well as nitrate reductase (NR), nitrite reductase (NiR), glutamine synthase (GS), glutamate synthetase (GOGAT) and glutamate dehydrogenase (GDH) activities were analysed in leaves. Boron toxicity significantly decreased leaf biomass, RGR(L), organic N, soluble proteins, and NR and NiR activities. The lowest NO(3) (-) and NH(4) (+) concentration in leaves was recorded when plants were supplied with 2.0 mM B in the root medium. Total B, amino acids, activities of GS, GOGAT and GDH increased under B toxicity. Data from the present study prove that B toxicity causes inhibition of NO(3) (-) reduction and increases NH(4) (+) assimilation in tomato plants.
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PMID:Response of nitrogen metabolism to boron toxicity in tomato plants. 1968 74

Leaf senescence is a highly regulated final phase of leaf development preceding massive cell death. It results in the coordinated degradation of macromolecules and the subsequent nutrient relocation to other plant parts. Very little is still known about early stages of leaf senescence during normal leaf ontogeny that is not triggered by stress factors. This paper comprises an integrated study of natural leaf senescence in tobacco plants grown in vitro, using molecular, structural, and physiological information. We determined the time sequence of ultrastructural changes in mesophyll cells during leaf senescence, showing that the degradation of chloroplast ultrastructure fully correlated with changes in chlorophyll content. The earliest degenerative changes in chloroplast ultrastructure coinciding with early chromatin condensation were observed already in mature green leaves. A continuum of degradative changes in chloroplast ultrastructure, chromatin condensation and aggregation, along with progressive decrease in cytoplasm organization and electron density were observed in the course of mesophyll cells ageing. Although the total amounts of endogenous cytokinins gradually increased during leaf ontogenesis, the proportion of bioactive cytokinin forms, as well as their phosphate precursors, in total cytokinin content rapidly declined with ageing. Endogenous indole-3-acetic acid (IAA) levels were strongly reduced in senescent leaves, and a decreasing tendency was also observed for abscisic acid (ABA) levels. Senescence-associated tobacco cysteine proteases (CP, E.C. 3.4.22) CP1 and CP23 genes were induced in the initial phase of senescence. Genes encoding glutamate dehydrogenase (GDH, E.C. 1.4.1.2) and one isoform of cytosolic glutamine synthetase (GS1, E.C. 6.3.1.2) were induced in the late stage of senescence, while chloroplastic GS (GS2) gene showed a continuous decrease with leaf ageing.
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PMID:Characterization of natural leaf senescence in tobacco (Nicotiana tabacum) plants grown in vitro. 2583 9

Nitrogen (N) is a key element for the production of potato. The N uptake efficiency, N use efficiency and increased N utilization efficiency can be decreased by N deficiency treatment. We performed this study to investigate the association between transcriptomic profiles and the efficiencies of N in potato. Potato cultivars "Yanshu 4" (short for Y), "Xiabodi" (cv. Shepody, short for X) and "Chunshu 4" (short for C) were treated with sufficient N fertilizer and deficient N fertilizer. Then, the growth parameters and tuber yield were recorded; the contents of soluble sugar and protein were measured; and the activities of enzymes were detected. Leaf and root transcriptomes were analyzed and differentially expressed genes (DEGs) in response to N deficiency were identified. The results showed that N deficiency decreased the nitrate reductase (NR), glutamine synthetase (GS) and root activity. Most of the DEGs between N-treated and N-deficiency participate the processes of transport, nitrate transport, nitrogen compound transport and N metabolism in C and Y, not in X, indicating the cultivar-dependent response to N deficiency. DEGs like glutamate dehydrogenase (StGDH), glutamine synthetase (StGS) and carbonic anhydrase (StCA) play key roles in these processes mentioned above. DEGs related to N metabolism showed a close relationship with the N utilization efficiency (UTE), but not with N use efficiency (NUE). The Major Facilitator Superfamily (MFS) members, like nitrate transporter 2.4 (StNRT2.4), 2.5 (StNRT2.5) and 2.7 (StNRT2.7), were mainly enriched in the processes associated with response to stresses and defense, indicating that N deficiency induced stresses in all cultivars.
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PMID:Transcriptome analysis reveals Nitrogen deficiency induced alterations in leaf and root of three cultivars of potato (Solanum tuberosum L.). 3311 30