Genetic and biomedical studies of regulation of nitrate reductase in Ustilago maydis. by Cynthia May Lewis

Cover of: Genetic and biomedical studies of regulation of nitrate reductase in Ustilago maydis. | Cynthia May Lewis

Published by University of East Anglia in Norwich .

Written in English

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Thesis (Ph.D.) - University of East Anglia, School of Chemical Sciences, 1968.

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Open LibraryOL14507739M

Download Genetic and biomedical studies of regulation of nitrate reductase in Ustilago maydis.

Regulation of nitrate reductase in the basidiomycete Ustilago maydis. Lewis CM, Fincham JR. Nitrate reductase was induced in Ustilago maydis by growth in medium containing only nitrate as the nitrogen source.

Ammonium ions repressed the enzyme and led to a rapid loss of activity. The ability of UV-sensitive (uvs -) and wild type (uvs +) strains of Ustilago maydis to synthesize the inducible enzyme nitrate reductase (NR) was examined following UV-exposure.

Low doses of UV-irradiation prior to induction inhibit to a greater degree the first appearance of NR in uvs - as compared to uvs + strains; in addition, the exponentially increasing rates of NR synthesis are.

Studies were done measuring the nitrate uptake and nitrate reductase activity in anoxic conditions to see if there was a difference in activity level and tolerance to anoxia. These studies found that nitrate reductase, in anoxic conditions improves the.

Possible structural genes for nitrate reductase have also been identified in Ustilago maydis (Lewis and Fincham, ) and Chlamydomonas reinhardii (Nichols et al., ). In E. coli De Moss () established that a ts mutation in the chl C resulted in a temperature-sensitive nitrate reductase in vitro.

Prokaryotic nitrate reduction can serve a number of physiological roles and can be catalysed by a number of biochemically distinct nitrate reductases. Three distinct nitrate reductase classes can be indentified in prokaryotes, NAS, NAR and NAP. NAS is located in the cytoplasmic compartment and participates in nitrogen assimilation.

NAR is usually a three-subunit complex. Amino acid modulation of NADPH-nitrate reductase activity is discussed in relation to the conservation of energy (NADPH) by Neurospora when nitrate is the nitrogen source.

Full text Get a printable copy (PDF file) of the complete article (M), or click on a page image below to browse page by page. for NADH: Nitrate Reductase (NaR) activity. The enzyme Nitrate Reductase (NaR) catalyzes the reduction of Nitrate to Nitrite using the natural electron donor NADH.

The nitrite reacts with color reagents (dyes) under acidic conditions to produce a visible magenta color. The color produced is directly proportional to the nitrate concentration. Nitrite reductase and its regulation Nitrite reductase (NiR) is a stromal enzyme that catalyses a six-electron step reduction of nitrite to ammonium using reduced Fd as electron donor.

The holoenzyme is encoded by a single gene clustered with other nitrate assimilation genes. NITRATE REDUCTASE STRUCTURE, FUNCTION AND REGULATION: Bridging the Gap between Biochemistry and Physiology Wilbur H.

Campbell Phytotechnology Research Center and Department of Biological Sciences, Michigan Technological University, Houghton, Michigan ; e-mail: [email protected] Nitrate Induction of Gene Expression Is Defective innrg1 Our analysis of nrg1 showed that nitrate induction of the NRP-YFP transgene was greatly diminished.

To determine if regulation of endogenous genes was similarly affected, nitrate regulation of several nitrate-inducible genes (NiR, NIA1, and NRT) was examined. Simplified scheme for regulation of nitrate reductase activity. Nitrate reductase (NR) is generally active in the light, and the main reaction catalysed is the reduction of NO 3 – into NO 2 –.

Nitrite is then further reduced and assimilated in the chloroplasts. Nitrate reductase-based nitrate testing replaces these older methods, which have potential to harm the environment, with an environmentally friendly method that is.

nitrate reductase Z, is located in the chlZlocus located at minutes, a region which includes a narK homologue, narU, but no apparent homologue to the. Nitrate reductase (NR) activity can be directly assayed using cut leaf segments.

In a solution containing nitrate, phosphate buffer and propanol, nitrate can readily enter leaf cells. In this case, the leaf cell supplies NR and the reductant NADH. The propanol in the assay medium increases.

The nitrate reductase from plants - our first enzyme product - reduces nitrate to nitrite, a first step in the chain that turns the elements into proteins and DNA. We eat NaR every day. NaR replaces cadmium, zinc, or vanadium reagents for reliable and environmentally benign nitrate measurement, in any lab format and for on-site nitrate testing.

Studies examining the infection process of the basidiomycete corn smut fungus Ustilago maydis have suggested that phytohormone manipulation, by. (Ntr) and specific induction by nitrate or nitrite [18, 26].

In the photosynthesizing bacterium R. capsulatusassimi-latory NRase is induced by nitrate and repressed by low C/N ratio [27]. Positive regulation by nitrate requires nitrate reduction to nitrite, evidently the real activator of the nitrate assimilation gene transcription [28, 29].

Exercise 2. The effect of nitrate concentration on the level of nitrate reductase activity In this exercise you will determine the effect of different nitrate concentrations on the level of nitrate reductase activity.

Planting and maintenance of the plants until the day of the experiment is the same as in exercise 1. Fig. Simplified scheme for regulation of nitrate reductase activity.

Nitrate reductase (NR) is generally active in the light, and the main reaction catalysed is the reduction of NO3 – into NO 2 –. Nitrite is then further reduced and assimilated in the chloroplasts. Nitrate is partioned between an active metabolic pool in the cytosol and.

Enterosalivary circulation pathway (nitrate reductase activity of bacteria on the tongue generates nitrite and nitrite which is metabolized to NO in the stomach and circulation) [Hord ].

Approximately 5%% of the total nitrate intake is converted to nitrite by bacteria in the saliva, stomach, and small intestine [Hord ]. Genetics and Molecular Research 14 (4): () ©FUNPEC-RP Characterization of novel nitrate reductase-deficient mutants for transgenic Dunaliella salina systems L.J.

Gao 1, Y.L. Jia2, S.K. Li3 and L.L. Qiu 1School of Basic Medicine, Xinxiang Medical University, Xinxiang, Henan, China 2Pharmacy College, Xinxiang Medical. Add two nitrate tablets to the sample. If the bacterium produces nitrate reductase, the broth will turn a deep red within 5 minutes at this step.

If no color change is observed, then the result is inconclusive. Add a small amount of zinc to the broth. If the solution remains colorless, then both nitrate reductase and nitrite reductase are. A nitrate reductase (NR)-null mutant of Arabidopsis was constructed that had a deletion of the major NR gene NIA2 and an insertion in the NIA1 NR gene.

This mutant had no detectable NR activity and could not use nitrate as the sole nitrogen source. Starch mobilization was not induced by nitrate in this mutant but was induced by ammonium, indicating that nitrate was not the.

The assimilation of N involves the nitrate reductase (NR) enzyme, and its activity seems to be dependent on N supply.

Molybdenum (Mo) is also important because it is a cofactor of NR. In this study, the variables of an in vivo assay were optimized for measuring nitrate reductase activity (NRA) in the leaves and stem tissues. Nitrate Assimilation: The Role of In Vitro Nitrate Reductase Assay as Nutritional Predictor.

By Fungyi Chow. Submitted: February 14th Reviewed: July 14th Published: March 2nd DOI: / Nitrate assimilation is the major process by which the major- ity of the higher plant species obtain reduced nitrogen. In this process, nitrate, once taken up from the soil, is reduced to nitrite by nitrate reductase (NR) (EC ).

Nitrite is translocated to the chloroplasts, where it. The nitrate anion is a simple, abundant and relatively stable species, yet plays a significant role in global cycling of nitrogen, global climate change, and human health.

Although it has been known for quite some time that nitrate is an important species environmentally, recent studies. I.U.B.: C.A.S.: (Cytochrome) Ferrocytochrome: nitrate oxidoreductase. Enzymatic Reaction (image will open in a new window).

This respiratory or "anaerobic" nitrate reductase (NR) (Cytochrome) from E. coli catalyzes the following reaction. It is a membrane-bound enzyme closely associated with formate dehydrogenase which, along with NR contains.

• A solution of 20 U Nitrate reductase in 2 ml double dist. water is stable for one week when stored at +2 to +8°C; for longer periods it is recommended to freeze the solution in aliquots. Effect of nitrate on the in vivo regulation of nitrate reductase. Role of atrazine on the regulation of nitrate reductase.

The nitrate reductase assay system was improved up to 10 fold over that previously used (28). This improvement included the addition of oxalacetic acid and malic dehydrogenase to the.

Showing a negative nitrate reduction reaction. Clostridium difficile (ATCC ® ) colonies growing on Brucella Agar with H and K (Cat. A30) with a Nitrate HardyDisk™ (Cat. Z) aseptically placed on the plate prior to anaerobic incubation (24 hours at 35 deg.

C.). One drop of Nitrate Reagent A (Cat. Z71) and one drop of Nitrate Reagent B (Cat. Z72) were. Start studying Exercise Nitrate Reduction Test. Learn vocabulary, terms, and more with flashcards, games, and other study tools.

The functional size, quaternary structure, functional domains, active site residues and immunological, spectroscopic, thermodynamic and kinetic properties of nitrate reductase are reviewed and discussed. The localization of nitrate reductase within the cell, its induction, repression and modulation of activity are also considered.

The role of nitrate reductase (NR) in the regulation of the nitrate assimilation pathway was evaluated in the yeast Hansenula anscriptional regulation of NR in response to reduced nitrogen sources and the effect of a heterologous NR on the transcriptional regulation of nitrate‐assimilatory gene expression was examined.

HORT - Metabolic Plant Physiology Nitrate uptake and reduction. Nitrate and nitrite reductase structures. Ferredoxin-nitrite reductase (NiR) [EC ] catalyzes the six-electron reduction of nitrite to ammonia, using reduced ferredoxin (Fd) as the electron donor.

The Fd-dependent NiRs of plants, algae and cyanobacteria are monomeric proteins with molecular masses near 63. Start studying Induction of Nitrate Reductase. Learn vocabulary, terms, and more with flashcards, games, and other study tools.

Cayman’s Nitrate/Nitrite Colorimetric Assay Kit provides an accurate and convenient method for measurement of total nitrate/nitrite concentration in a simple two-step process. The first step is the conversion of nitrate to nitrite utilizing nitrate reductase.

The second step is. SUMMARY V Summary Background: In a previous study, nitrate reductase (NR, EC ) from leaves of Ricinus communis L. showed different regulatory properties from most other higher plants NR's by an unusually strong Mg2+-sensitivity, a different pH-activity profile and only little ATP-dependent inactivation.

The aim of this work was to elucidate the deviating properties of. Enzymatic Assay of NITRATE REDUCTASE (EC ) REFERENCES: Biochimica et Smarrelli, Jr., J. and Campbell, W.H. () Biophysica ActaNOTES: 1.

Perform the color development of the Test and Standards at the same time in order to prevent deviations in color development from the standard curve. This assay is based on the cited. Assimilatory nitrate reductase (NR) of higher plants is highly regulated in a very complex manner, and many recent reviews have highlighted different aspects of that regulation.

Here, current knowledge of the post‐translational regulation is briefly summarized, putting emphasis on new insights obtained recently by immunological techniques. ADVERTISEMENTS: Read this article to learn about the performance of nitrate reduction test on bacteria to find out their ability to reduce nitrates!

Principle: Some bacteria have the ability to reduce nitrates, as they can produce the enzyme ‘nitrate reductase’. ADVERTISEMENTS: This enzyme, in presence of suitable electron donor, reduces nitrates (N03–) to nitrites (N02–).Kinetin seems to modulate the effectivity of gibberellin on the determination of nitrate reductase activity: the larger the amount of kinetin added the smaller the concentration of GA 3 required to obtain maximal activity of nitrate reductase.

The effect of both growth substances on the enzyme is not due to a general protein synthesis stimulation.Publications by Athel Cornish-Bowden. This page lists the publications by Athel Cornish-Bowden on the kinetic properties of nitrite reductase () and nitrate reductase (present).

D: Nitrite reductase () and nitrate reductase (present).

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