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:1.7.1.4 (nitrite reductase)
1,847 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Nitrogen-14 and nitrogen-15 nuclear magnetic resonance (NMR) spectra were recorded for freshly dissected buds of Picea glauca and for buds grown for 3, 6 and 9 weeks on shoot-forming medium. Resonances for Glu (and other alphaNH(2) groups), Pro, Ala, and the side chain groups in Gln, Arg, Orn, and gamma-aminobutyric acid could be detected in in vivo(15)N NMR spectra. Peaks for alpha-amino groups, Pro, NO(3) (-) and NH(4) (+) could also be identified in (14)N NMR spectra. Perfusion experiments performed for up to 20 hours in the NMR spectrometer showed that (15)N-labeled NH(4) (+) and NO(3) (-) are first incorporated into the amide group of Gln and then in the alphaNH(2) pool. Subsequently, it also emerges in Ala and Arg. These data suggest that the glutamine synthetase/ glutamate synthase pathway functions under these conditions. The assimilation of NH(4) (+) is much faster than that of NO(3) (-). Consequently after 10 days of growth more than 70% of the newly synthesized internal free amino acid pool derives its nitrogen from NH(4) (+) rather than NO(3) (-). If NH(4) (+) is omitted from the medium, no NO(3) (-) is taken up during 9 weeks and the buds support limited growth by utilizing their endogenous amino acid pools. It is concluded that NH(4) (+) and NO(3) (-) are both required for the induction of nitrate- and nitrite reductase.
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PMID:A N and N Nuclear Magnetic Resonance Study of Nitrogen Metabolism in Shoot-Forming Cultures of White Spruce (Picea glauca) Buds. 1666 96

Here, we study the effect caused by three trace elements--Al, Se, and Mo--applied at the same concentration (100 microM) and in their oxyanionic forms--NaAl(OH)(4), Na(2)SeO(4), and Na(2)MoO(4)--on NO(3)(-) assimilation (NO(3)(-), nitrate reductase (NR), nitrite reductase (NiR), glutamine synthetase (GS), and glutamate synthase (GOGAT) activities, and concentrations of amino acids and proteins) in sunflower (Helianthus annuus L. var. Kasol) plants. The most harmful element for sunflower plants proved to be selenate, followed by aluminate. On the contrary, the application of molybdate had no negative effect on the growth of this plant, suggesting the possibility of using sunflower for the phytoremediation of this metal, mainly in agricultural zones used for grazing where the excess of this element can provoke problems of molybdenosis in ruminants (particularly in cattle). In addition, we found that the alteration of NO(3)(-) assimilation by SeO(4)(2-) and Al(OH)(4)(-) directly influences the growth and development of plants, foliar inhibition of NR activity by SeO(4)(2-) being more harmful than the decrease in foliar availability of NO(3)(-) provoked by Al(OH)(4)(-).
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PMID:Comparative effect of Al, Se, and Mo toxicity on NO3(-) assimilation in sunflower (Helianthus annuus L.) plants. 1680 59

The Synechococcus sp. PCC 7942 nitrogen regulator PipX interacts in a 2-oxoglutarate-dependent manner with the global nitrogen transcription factor NtcA and the signal transduction protein P(II). In vivo, PipX is involved in the NtcA-dependent induction of glnB and glnN genes. To further investigate the extent to which PipX is involved in global nitrogen control, the effect of pipX inactivation on various nitrogen-regulated processes was determined. The PipX-deficient mutant was able to use nitrate as a nitrogen source and to efficiently inhibit the nitrate transport upon ammonium addition but showed decreased nitrate and nitrite reductase activities and a delay in the induction of nitrate utilization after transfer of cultures from ammonium- to nitrate-containing media. In contrast to the wild-type, glutamine synthetase activity was not upregulated upon depletion of combined nitrogen from cultures of the mutant strain. Inactivation of pipX impaired induction of nblA and delayed phycobilisome degradation, but did not affect recovery of nitrogen-deprived cultures. Taken together, the results indicate that PipX interacts with NtcA to facilitate efficient acclimation of cyanobacteria to conditions of nitrogen limitation.
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PMID:Role of the Synechococcus PCC 7942 nitrogen regulator protein PipX in NtcA-controlled processes. 1732 91

In this paper, the biological traits, physiological parameters, and enzyme activities related to N assimilation and metabolism of wheat varieties with different nitrogen (N) efficiency were studied under low and high N supply. The results showed that under low N supply, the dry mass of root, leaf, and stem as well as the accumulated N amount in plant were in the order of high N efficiency variety > mid N efficiency variety > low N efficiency variety. The variety with high N uptake efficiency (Ji 97-6360) under low N supply had the highest root active absorption area and TTC-reductive activity and the highest leaf nitrate reductase activity and NO3- content, while the variety with high N physiological efficiency (Shixin 5418) had higher nitrite reductase and glutamine synthetase activities but lower NO3- content and NR activity in its leaf. There was a significant positive correlation between nitrogen use efficiency (NUE) and nitrogen uptake index (NUI) under low N supply. The biological traits, physiological parameters, and enzyme activities related to nitrogen assimilation and metabolism of test wheat varieties were not always the same under high and low N supply.
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PMID:[Responses and corresponding physiological mechanisms of different wheat varieties in their nitrogen efficiency and nitrogen uptake to nitrogen supply]. 1761 76

Knowledge about nitrogen metabolism and control in the genus Mycobacterium is sparse, especially compared to the state of knowledge in related actinomycetes like Streptomyces coelicolor or the close relative Corynebacterium glutamicum. Therefore, we screened the published genome sequences of Mycobacterium smegmatis, Mycobacterium tuberculosis, Mycobacterium bovis, Mycobacterium avium ssp. paratuberculosis and Mycobacterium leprae for genes encoding proteins for uptake of nitrogen sources, nitrogen assimilation and nitrogen control systems, resulting in a detailed comparative genomic analysis of nitrogen metabolism-related genes for all completely sequenced members of the genus. Transporters for ammonium, nitrate, and urea could be identified, as well as enzymes crucial for assimilation of these nitrogen sources, i.e. glutamine synthetase, glutamate dehydrogenase, glutamate synthase, nitrate reductase, nitrite reductase, and urease proteins. A reduction of genes encoding proteins for nitrogen transport and metabolism was observed for the pathogenic mycobacteria, especially for M. leprae. Signal transduction components identified for the different species include adenylyl- and uridylyltransferase and a P(II)-type signal transduction protein. Exclusively for M. smegmatis, two homologs of putative nitrogen regulatory proteins were found, namely GlnR and AmtR, while in other mycobacteria, AmtR was absent and GlnR seems to be the nitrogen transcription regulator protein.
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PMID:A genomic view on nitrogen metabolism and nitrogen control in mycobacteria. 1882 37

The effects through which an alfalfa protein hydrolysate (EM) possessing gibberellin- and auxin-like activity may promote plant nitrogen (N) nutrition have been investigated in Zea mays L. Treatment with 0.01 or 0.1 mg L(-1) EM for 48 h resulted in enhanced plant growth and leaf sugar accumulation. Concomitantly, the level of nitrates decreased, whereas total N percentage was unchanged. The activity of a number of enzymes involved in carbon (C) metabolism (malate dehydrogenase, MDH; isocitrate dehydrogenase, IDH; citrate synthase, CS) and N reduction and assimilation (nitrate reductase, NR; nitrite reductase, NiR; glutamine synthetase, GS; glutamate synthase, GOGAT; aspartate aminotransferase, AspAT) was significantly induced by EM supply to plants, and the transcription pattern of MDH, IDH, CS, and NR strongly correlated with data of enzyme activity. The transcript accumulation of asparagine synthetase (AS) was also induced by EM in the roots. The results suggest that EM might promote nitrogen assimilation in plants through a coordinate regulation of C and N metabolic pathways and open the way for further research on protein hydrolysates as a valid tool to improve N use efficiency and, as a consequence, to reduce the intensive use of inorganic N fertilizers in agriculture.
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PMID:Effects of an alfalfa protein hydrolysate on the gene expression and activity of enzymes of the tricarboxylic acid (TCA) cycle and nitrogen metabolism in Zea mays L. 1905 64

The influences of 50 and 100muM Ni on growth, tissue Ni accumulation, concentrations of nitrate, ammonium, glutamate, and proline as well as the activities of nitrate reductase (NR), nitrite reductase (NiR), glutamine synthetase (GS), glutamate synthase (GOGAT), glutamate dehydrogenase (GDH), alanine aminotransferase (AlaAT), and aspartate aminotransferase (AspAT) were examined in the shoots of wheat seedlings cv. Zyta. Exposure of the seedlings to Ni resulted in a rapid accumulation of this metal in the shoots, which was accompanied by significant reduction in fresh weight of these organs. Tissue nitrate content decreased in response to Ni stress, while ammonium concentration increased substantially. Glutamate concentration was slightly lowered up to the 4th day of the metal exposure. In contrast, proline content increased significantly, starting from the first day after Ni treatment. NR activity showed a decline of up to 40% below the control level after Ni application; however, its activation state remained unaltered. Heavy metal treatment also resulted in a marked decrease in NiR activity, which after 7d of exposure to 100muM Ni was almost 80% lower than in the control. GS activity in wheat shoots was not influenced by Ni application. Contrary to Fd-GOGAT exhibiting reduced activity in the shoots of Ni-treated wheat seedlings, NADH-GOGAT activity was considerably enhanced, exceeding the control value even by 165%. After 7d of exposure to Ni, both NADH-GDH and NAD-GDH activities in wheat shoots were markedly induced; however, NAD-GDH activity showed a significant decrease at the early stage of the experiment. Both AlaAT and AspAT glutamate-producing activities were considerably stimulated by Ni treatment. Our results suggest that induction of NADH-GOGAT, NADH-GDH, AlaAT, and AspAT activities may compensate for the reduced Fd-GOGAT activity and serve as an alternative means of glutamate synthesis in wheat shoots under Ni stress.
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PMID:Nickel-induced changes in nitrogen metabolism in wheat shoots. 1918 88

Light perceived by phytochromes will induce genes of nitrogen assimilation, however, transducing components in the signaling cascades to these genes are hardly known. Recently the bZIP transcription factors HY5 (LONG HYPOCOTYL5) and HYH (HOMOLOG OF HY5) were identified as positive regulators in light activation of NIA2 (nitrate reductase 2). The bHLH transcription factor PIF4 (PHYTOCHROME INTERACTING FACTOR 4) was revealed as an inhibitor of NIA2 expression. In contrast to NIA2, expression of other genes of nitrogen assimilation, NRT1.1 (dual-affinity nitrate transporter 1.1), NIA1 (nitrate reductase 1), NIR (nitrite reductase), GLN2 (glutamine synthetase 2) and GLU1 (glutamate synthase 1) were not promoted by HY5/HYH or inhibited by PIF4. NIA2 as the outstanding gene of nitrate assimilation regarding HY5/HYH and PIFs may have evolved in connection with the cytosolic leaf localization of nitrate reductase, and adverse effects of the products, nitrite, nitric oxide and active oxygen species formed by the enzyme.
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PMID:Unique status of NIA2 in nitrate assimilation: NIA2 expression is promoted by HY5/HYH and inhibited by PIF4. 2000 59

Nitric oxide (NO) stimulated the activity of plasma membrane H+-ATPase, 5'-nucleotidase, peroxidase, ascorbate peroxidase and glutathione reductase in ultraviolet B (UV-B) irradiated Chlorella pyrenoidosa. It also boosted the activity of nitrogen-metabolism enzymes such as nitrate reductase, nitrite reductase, glutamine synthetase, which were inhibited by UV-B irradiation. The chlorophyll fluorescence ratio (Fv/Fm) of the UV-B irradiated algae and decreased continuously after the cells were transferred to UV-B irradiation. A continuing decrease of the Fv/Fm was observed even after the cells were transferred to photosynthetically active radiation (PAR). After adaptation for 8 h under PAR (after treatment with nitric oxide), Fv/Fm recovered to 55 % of normal levels--without NO the value approached zero. Exogenous NO stopped the decay of chlorophyll and thylakoid membrane in cells exposed to UV-B irradiation. NO plays probably a key role in damage induced by UV-B irradiation in green algae.
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PMID:Nitric oxide plays a role as second messenger in the ultraviolet-B irradiated green alga Chlorella pyrenoidosa. 2033 5

We analyzed the effect of omission of sulfur (S) from the nutrient solution and then restoration of S-source on the uptake and assimilation of nitrate in rapeseed. Incubation in nutrient solution without S for 1-6 days led to decline in uptake of nitrate, activities, and expression levels of nitrate reductase (NR) and glutamine synthetase (GS). The nitrite reductase (NiR) and glutamate synthase (GOGAT) activities were not considerably affected. There was significant enhancement in nitrate content and decline in sulfate content. Evaluation of amino acid profile under S-starvation conditions showed two- to fourfold enhancement in the contents of arginine, asparagine and O-acetyl-L-serine (OAS), whereas the contents of cysteine and methionine were reduced heavily. When the S-starved plants were subjected to restoration of S for 1, 3, 5, and 7 days, activities and expression levels of NR and GS recovered within the fifth and seventh days of restoration, respectively. Exogenous supply of metabolites (arginine, asparagine, cysteine, glutamine, OAS, and methionine) also affected the uptake and assimilation of nitrate, with a maximum for OAS. These results corroborate the tight interconnection of S-nutrition with nitrate assimilation and that OAS plays a major role in this regulation. The study must be helpful in developing a nutrient-management technology for optimization of crop productivity.
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PMID:Sulfur starvation and restoration affect nitrate uptake and assimilation in rapeseed. 2055 52


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