Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.7.1.2 (nitrate reductase)
 3,861 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Chlorate, the chlorine analog of nitrate, is a herbicide that has been used to select mutants impaired in the process of nitrate assimilation. In Arabidopsis thaliana, mutations at any one of eight distinct loci confer resistance to chlorate. The molecular identities of the genes at these loci are not known; however, one of these loci--chl3--maps very near the nitrate reductase structural gene NIA2. Through the isolation, characterization, and genetic analysis of new chlorate-resistant mutants generated by gamma irradiation, we have been able to demonstrate that the CHL3 gene and the NIA2 gene are identical. Three new chlorate-resistant mutants were identified that had deletions of the entire NIA2 gene. These nia2 null mutants were viable and still retained 10% of wild-type nitrate reductase activity in the leaves of the plants. All three deletion mutations were found to be new alleles of chl3. Introduction of the NIA2 gene back into these chl3 mutants by Agrobacterium-mediated transformation partially complemented their mutant phenotype. From these data, we conclude that Arabidopsis has at least two functional nitrate reductase genes and that the NIA2 gene product accounts for the majority of the leaf nitrate reductase activity and chlorate sensitivity of Arabidopsis plants.
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PMID:Identification of the Arabidopsis CHL3 gene as the nitrate reductase structural gene NIA2. 184 Sep 22

Tap water is one of the causative factors of hospital infections. We examined the disinfective potential of electrolysis and mechanism of disinfection, and clarified the disinfective effect of electrolysis on tap water contaminated with bacteria, and discussed its clinical applications. Tap waters artificially contaminated with Pseudomonas aeruginosa, Escherichia coli, Legionella pneumophila, and Staphylococcus aureus could be sterilized by electrolysis at 20-30 mA for 5 min. A high-density suspension (10(6) CFU/ml) of a spore forming bacterium, Bacillus subtilis was not completely sterilized by electrolysis at 50 mA up to 30 min, but a low-density suspension (10(5) CFU/ml) was totally sterilized by electrolysis at 50 mA for 5 min. Electrolyzed P. aeruginosa changed morphologically, that is, there was bleb formation on the cell wall and irregular aggregation of cytoplasmic small granules. Moreover, cytoplasmic enzyme, nitrate reductase, was inactivated by the electrolysis. On the other hand, genomic DNA of the electrolyzed bacteria was not degenerated, therefore, their DNA polymerase activity was not completely inactivated. Consequently, the major agent in electrolysis for bactericidal action was considered to be free chlorine, and the possible bactericidal mechanism was by destruction of bacterial membranes, followed by the aggregation of peripheral cytoplasmic proteins. Electrolysis of tap water for both disinfecting contaminating bacteria and increasing the disinfectant capacity was considered effective with some limitations, particularly against high-density contamination by spore-forming bacteria. In clinical settings, electrolysis of tap water is considered effective to disinfect water for hand washing in operation theatres, and bathing water for immunocompromised hosts.
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PMID:Evaluation of disinfective potential of reactivated free chlorine in pooled tap water by electrolysis. 1506 56

Activity of nitrate reductase from Triticum aestivum L. seedlings was decreased by deficiencies of molybdenum, zinc, and chlorine. Nitrate accumulated in molybdenum-deficient seedlings, declined in zinc-deficient seedlings, and was unaffected by the other micronutrient treatments. Glutamic acid dehydrogenase activity was decreased by deficiency of molybdenum, the only nutrient that affected the enzyme. Glutamine synthetase activity was decreased only by copper deficiency, and glutamic-oxaloacetic transaminase was not affected by any micronutrient deficiencies. Incorporation of (14)C-leucine into protein by wheat seedlings was increased by molybdenum deficiency, apparently because of decreased inhibition from endogenous amino acids, and was decreased by copper deficiency. Protein content was not affected significantly by the micronutrient treatments.
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PMID:Nitrogen Assimilation and Protein Synthesis in Wheat Seedlings as Affected by Mineral Nutrition. II. Micronutrients. 1665 14

Initial rate studies of spinach (Spinacia oleracea L.) nitrate reductase showed that NADH:nitrate reductase activity was ionic strength dependent with elevated ionic concentration resulting in inhibition. In contrast, NADH:ferricyanide reductase was markedly less ionic strength dependent. At pH 7.0, NADH:nitrate reductase activity exhibited changes in the V(max) and K(m) for NO(3) (-) yielding V(max) values of 6.1 and 4.1 micromoles NADH per minute per nanomoles heme and K(m) values of 13 and 18 micromolar at ionic strengths of 50 and 200 millimolar, respectively. Control experiments in phosphate buffer (5 millimolar) yielded a single K(m) of 93 micromolar. Chloride ions decreased both NADH:nitrate reductase and reduced methyl viologen:nitrate reductase activities, suggesting involvement of the Mo center. Chloride was determined to act as a linear, mixed-type inhibitor with a K(i) of 15 millimolar for binding to the native enzyme and 176 millimolar for binding to the enzyme-NO(3) (-) complex. Binding of Cl(-) to the enzyme-NO(3) (-) complex resulted in an inactive E-S-I complex. Electron paramagnetic resonance spectra showed that chloride altered the observed Mo(V) lineshape, confirming Mo as the site of interaction of chloride with nitrate reductase.
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PMID:Chloride inhibition of spinach nitrate reductase. 1666 71

When grown anaerobically on a succinate+nitrate (SN) medium, Paracoccus denitrificans forms the membrane-bound, cytoplasmically oriented, chlorate-reducing nitrate reductase Nar, while the periplasmic enzyme Nap is expressed during aerobic growth on butyrate+oxygen (BO) medium. Preincubation of SN cells with chlorate produced a concentration-dependent decrease in nitrate utilization, which could be ascribed to Nar inactivation. Toluenization rendered Nar less sensitive to chlorate, but more sensitive to chlorite, suggesting that the latter compound may be the true inactivator. The Nap enzyme of BO cells was inactivated by both chlorate and chlorite at concentrations that were at least two orders of magnitude lower than those shown to affect Nar. Partial purification of Nap resulted in insensitivity to chlorate and diminished sensitivity to chlorite. Azide was specific for SN cells in protecting nitrate reductase against chlorate attack, the protective effect of nitrate being more pronounced in BO cells. The results are discussed in terms of different metabolic activation of chlorine oxoanions in both types of cells, and limited permeation of chlorite across the cell membrane.
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PMID:Interference of chlorate and chlorite with nitrate reduction in resting cells of Paracoccus denitrificans. 1715 4

The Chloride Channel (CLC) gene family is reported to be involved in vacuolar nitrate (NO3-) transport. Nitrate distribution to the cytoplasm is beneficial for enhancing NO3- assimilation and plays an important role in the regulation of nitrogen (N) use efficiency (NUE). In this study, genomic information, high-throughput transcriptional profiles, and gene co-expression analysis were integrated to identify the CLCs (BnaCLCs) in Brassica napus. The decreased NO3- concentration in the clca-2 mutant up-regulated the activities of nitrate reductase and glutamine synthetase, contributing to increase N assimilation and higher NUE in Arabidopsis thaliana. The genome-wide identification of 22BnaCLC genes experienced strong purifying selection. Segmental duplication was the major driving force in the expansion of the BnaCLC gene family. The most abundant cis-acting regulatory elements in the gene promoters, including DNA-binding One Zinc Finger, W-box, MYB, and GATA-box, might be involved in the transcriptional regulation of BnaCLCs expression. High-throughput transcriptional profiles and quantitative real-time PCR results showed that BnaCLCs responded differentially to distinct NO3- regimes. Transcriptomics-assisted gene co-expression network analysis identified BnaA7.CLCa-3 as the core member of the BnaCLC family, and this gene might play a central role in vacuolar NO3- transport in crops. The BnaCLC members also showed distinct expression patterns under phosphate depletion and cadmium toxicity. Taken together, our results provide comprehensive insights into the vacuolar BnaCLCs and establish baseline information for future studies on BnaCLCs-mediated vacuolar NO3- storage and its effect on NUE.
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PMID:Genome-scale characterization of the vacuole nitrate transporter Chloride Channel (CLC) genes and their transcriptional responses to diverse nutrient stresses in allotetraploid rapeseed. 3057 34