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2 edition of inhibition of nitrogen assimilation in Lemna minor L.. found in the catalog.

inhibition of nitrogen assimilation in Lemna minor L..

Jonathan Andrew Goodchild

inhibition of nitrogen assimilation in Lemna minor L..

by Jonathan Andrew Goodchild

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  • 21 Currently reading

Published by University of East Anglia in Norwich .
Written in English


Edition Notes

Thesis (Ph.D.), School of Biological Sciences, University of East Anglia, 1985.

ID Numbers
Open LibraryOL14509073M

When Lemna is deprived of nitrogen, growth and respiration decrease and the pattern of 14 CO 2 release from [ C]glucose and [ C]glucose is consistent with a relatively strong inhibition of glycolysis. Protein degradation is enhanced but the concentration of free amino acid decreases. It is argued that the biological significance of the increased protein degradation .   Plants can suffer ammonium (NH4 +) toxicity, particularly when NH4 + is supplied as the sole nitrogen source. However, our knowledge about the underlying mechanisms of NH4 + toxicity is still largely unknown. Lemna minor, a model duckweed species, can grow well in high NH4 + environment but to some extent can also suffer toxic effects. The transcriptomic and physiological analysis of L. minor.

Abstract. Prior to , glutamate dehydrogenase (GDH; EC ) was considered to be the major route of ammonia assimilation in higher plants, 1–3 as in yeast, where clear kinetic evidence (specifically, the direct incorporation of 15 NH 4 + into glutamic acid) exists for the operation of a GDH pathway of glutamate biosynthesis. 4,5 However, since the discovery of . The regulation of ammonia assimilating enzymes in Lemna minor L. Planta (). Rhodes D, Sims AP, Stewart GR. Glutamine synthetase and the control of nitrogen assimilation in Lemna minor L. In "Nitrogen Assimilation of Plants", (Hewitt EJ, Cutting CV, ed), Academic Press, London & New York, pp ().

Lemna gibba L. G3, L. minor L. and L. paucicostata Hegelm. were initially cultured in a nitrogen-sufficient nutrient medium, where they maintained . Methionine sulfoximine (MSX), an inhibitor of GS, has little effect on cell division and nitrogen assimilation of cells growing on NH 4 +. Cells growing on NO 3-, however, show marked inhibition (65%) in nitrogen assimilation in the presence of 5 mM MSX. This MSX concentration also causes growth retardation and a progressive decrease in cell.


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Inhibition of nitrogen assimilation in Lemna minor L. by Jonathan Andrew Goodchild Download PDF EPUB FB2

Abstract. In L. minor grown in sterile culture, the primary enzymes of nitrate assimilation, nitrate reductase (NR), nitrite reductase (NiR) and glutamate dehydrogenase (GDH) change in response to nitrogen source. NR and NiR levels are low when grown on amino acids (hydrolyzed casein) or ammonia; both enzymes are rapidly induced on addition of nitrate, while addition of nitrite Cited by:   Lemna minor grown in sterile culture on a minerals-sucrose medium can utilize as nitrogen source, in order of increasing growth rate: ammonia, nitrate, a mixture of glutamic and aspartic acids plus arginine, or a balanced mixture of amino acids (hydrolyzed casein).

Maximum growth is found with nitrate plus hydrolyzed casein. Many synthetic mixtures of amino acids Cited by: Abstract. Aminooxyacetate, a known inhibitor of transaminase reactions and glycine decarboxylase, promotes rapid depletion of the free pools of serine and aspartate in nitrate grown Lemna minor L.

This compound markedly inhibits the methionine sulfoximine-induced accumulation of free ammonium ions and greatly restricts the methionine sulfoximine-induced Cited by: Abstract. When Lemna minor L. is supplied with the potent inhibitor of glutamine synthetase, methionine sulfoximine, rapid changes in free amino acid levels occur.

Glutamine, glutamate, asparagine, aspartate, alanine, and serine levels decline concomitantly with ammonia accumulation. However, not all free amino acid pools deplete in response to this by: Platnt I'l-Pysiol.

('Q) 44 Nitrogen Inhibition of nitrogen assimilation in Lemna minor L. book of Lemna minor. Enzymes of Nitrate Assimilation and Some Aspects of Their Regulation' K.

Joy Department of Biology, Carleton University, Ottawa, Canada Received Janu Abstract. In L. minor grown in sterile culture, the primary enzymes of nitrate assimilation,Cited by:   Azaserine is an analogue of glutamine and is an inhibitor of glutamine amide transfer reactions [6], including the glutamate synthase of Lemna minor [4].

The responses to these two inhibitors suggest that glutamine synthetase is the principal enzyme for ammonia assimilation and that the synthesis of glutamate occurs via glutamate synthase.

The effect of nitrate and ammonium on the extractable activity of two enzymes of assimilatory sulfate reduction, ATP sulfurylase (EC [][1]) and adenosine 5′-phosphosulfate sulfotransferase (APSSTase), was examined in Lemna minor L. cultivated under steady state conditions.

Nitrate reductase (EC [][1]) was measured for comparison. Low nitrate. The high affinity of Lemna minor glutamine synthetase for ammonium (K app m – × 10 −5 M) and its strong inhibition by ADP and 5‐AMP contrasts with the low affinity (K app m 3 × 10 −2 M) for ammonium and lack of inhibition by ATP shown by glutamate dehydrogenase.

Glutamine synthetase was inhibited by alanine, aspartate, glycine and serine while glutamate. Regulation of Sulfate Assimilation by Nitrogen Nutrition in the Duckweed Lemna minor L Article (PDF Available) in Plant physiology 76(3) December with 38.

Nitrogen Metabolism of Lemna minor. Growth, Nitrogen Sources and Amino Acid Inhibition' K. Joy Biology Department, Carleton University, Ottawa. Canada Received January Abstract. Lemna minor grown in sterile culture on a minerals-sucrose medium can utilize as nitrogen source, in order of increasing growth rate: ammonia, nitrate.

LEMNA MINOR L. BY G. STEWART and DAVID RHODES* Department of Botany, The University, Manchester Ml 3 09PL, U.K. (Received 18 February ) SUMMARY The high affinity of Lemna minor glutamine synthetase for ammonium (K app — x M) and its strong inhibition by ADP and 5-AMP contrasts with the low affinity (1.

Abstract. Ammonium assimilation was followed in N-starved mycelia from the ectomycorrhizal Ascomycete Cenococcum graniforme. The evaluation of free amino acid pool levels after the addition of 5 millimolar NH 4 + indicated that the absorbed ammonium was assimilated rapidly.

Post-feeding nitrogen content of amino acids was very different from the initial values. Inhibition of TOR increases nitrogen assimilation. In cells with active TOR, as part of the TORC1 complex, nitrogen import and assimilation occur normally. In cells where TORC1 function has been inhibited by rapamycin, increased nitrogen import (via the ammonium transporter AMT) and assimilation causes an increase in free amino acids.

The high affinity of Lemna minor glutamine synthetase for ammonium (Kappm – × 10−5 M) and its strong inhibition by ADP and 5-AMP contrasts with the. Rhodes D, Rendon GA, Stewart GR The regulation of ammonia assimilating enzymes in Lemna minor L. Planta Rhodes D, Sims AP, Stewart GR Glutamine synthetase and the control of nitrogen assimilation in Lemna minor L.

In "Nitrogen Assimilation of Plants", (EJ Hewitt, CV Cutting eds), Academic Press, London & New York. Abstract. Lemna minor grown in sterile culture on a minerals-sucrose medium can utilize as nitrogen source, in order of increasing growth rate: ammonia, nitrate, a mixture of glutamic and aspartic acids plus arginine, or a balanced mixture of amino acids (hydrolyzed casein).

Maximum growth is found with nitrate plus hydrolyzed casein. Many synthetic mixtures of amino acids. Cultures of Lemna gibba L. G3 were maintained at a constant, N-limited growth rate by adding nitrate daily in amounts calculated to sustain a rate of culture N increment of day(-1). The inhibition of nitrogen assimilation in Lemna minor L Author: Goodchild, J.

ISNI: Awarding Body: University of East Anglia Current Institution: University of East Anglia Date of Award: Availability of Full Text: Access from EThOS. Net K-efflux from duckweed (Lemna minor L.) was initiated by the addition of NH 4 Cl to nutrient medium with NO 3 as the only nitrogen NH 4-salts (sulfate or nitrate) were also effective, while LiCl, NaCl, RbCl or CsCl caused no major K-release under the sameRb and Cs ions lowered the net K-uptake observed in controls with.

Rhodes D, Sims AP, Folkes BF Pathway of ammonia assimilation in illuminated Lemna minor. Phytochem. Phytochem.

Robinson SA, Slade AP, Fox GG, Phillips R, Ratcliffe RG, Stewart GR The role of glutamate dehydrogenase in plant nitrogen. Lemna minor, the common duckweed or lesser duckweed, is an aquatic freshwater plant of the genus belong to the subfamily of Lemnaceae, which are monophyletic to the family Araceae.

L. minor is used as animal fodder, bioremediator, for wastewater nutrient recovery, and other applications.Cysteine synthesis from sulfide and O -acetyl-l-serine (OAS) is a reaction interconnecting sulfate, nitrogen, and carbon assimilation.

Using Lemna minor, we analyzed the effects of omission of CO2 from the atmosphere and simultaneous application of alternative carbon sources on adenosine 5′-phosphosulfate reductase (APR) and nitrate reductase (NR), the key enzymes of .The presence of ammonium is shown to inhibit the nitrate-promoted formation of nitrate reductase in Lemna minor L.

The ammonium inhibition does not result from an inhibition of nitrate accumulation. The kinetics of the ammonium inhibition suggest it is not a direct effect of ammonium. The inhibition could result from the build up of a product of ammonium assimilation .