Corrigendum to: Ammonium metabolism in Selaginella bryopteris in response to dehydration-rehydration and characterisation of desiccation tolerant, thermostable, cytosolic glutamine synthetase from plant

2021 ◽  
Vol 48 (3) ◽  
pp. 358
Author(s):  
Kamal K. Singh ◽  
Shyamaprasad Saha ◽  
Ram C. Kadiravana ◽  
Deepika Mazumdar ◽  
Vijeta Rai ◽  
...  
Keyword(s):  
Glutamine Synthetase ◽  
Metabolic Regulation ◽  
Specific Activity ◽  
Higher Plants ◽  
Glutamate Synthase ◽  
Immunoblot Analysis ◽  
Primary Metabolism ◽  
Ammonium Metabolism ◽  
Free Ammonium ◽  
Selaginella Bryopteris

Water deficit (WD) has adverse effects on plant growth, and acclimation requires responses allowing primary metabolism to continue. Resurrection plants can serve as model system to gain insight into metabolic regulation during WD. We herein report the response of a resurrection lycophyte, Selaginella bryopteris, to dehydration-rehydration cycle with emphasis on ammonium metabolism. Dehydration of S. bryopteris fronds resulted in decrease of total protein and increase of free ammonium levels and the effect was reversed on rehydration. The proline content increased twice after 24 h of dehydration, which again recovered to background levels comparable to that at full turgor state. The specific activity of glutamine synthetase (GS) didn’t change significantly till 6 h and then declined by 21% after 24 h of dehydration, whereas specific activities of glutamate synthase (GOGAT) and aminating glutamate dehydrogenase (GDH) were enhanced significantly during dehydration. The deaminating activity of GDH also increased during dehydration albeit at a slower rate. Immunoblot analysis indicated overexpression of GS and GDH polypeptides during dehydration and their levels declined on rehydration. The results suggested significant role of GDH along with GS/GOGAT in production of nitrogen-rich amino acids for desiccation tolerance. Unlike higher plants S. bryopteris expressed GS only in cytosol. The enzyme had pH and temperature optima of 5.5 and 60°C, respectively, and it retained 96% activity on preincubation at 60°C for 30 min indicating thermostability. Hence, like higher plants the cytosolic GS from S. bryopteris has a conserved role in stress tolerance.

Ammonia, glutamine, and asparagine: a carbon–nitrogen interface

1988 ◽  
Vol 66 (10) ◽  
pp. 2103-2109 ◽  
Author(s):  
K. W. Joy
Keyword(s):  
Glutamine Synthetase ◽  
Glutamate Dehydrogenase ◽  
Higher Plants ◽  
Amino Nitrogen ◽  
Glutamate Synthase ◽  
Dinitrogen Fixation ◽  
Similar Function ◽  
Metabolic Processes ◽  
Organic Form ◽  
Primary Input

In plants, the primary input of nitrogen (obtained from the soil or from symbiotic dinitrogen fixation) occurs through the assimilation of ammonia into organic form. Synthesis of glutamine (via glutamine synthetase) is the major, and possibly exclusive, route for this process, and there is little evidence for the participation of glutamate dehydrogenase. A variety of reactions distribute glutamine nitrogen to other compounds, including transfer to amino nitrogen through glutamate synthase. In many plants asparagine is a major recipient of glutamine nitrogen and provides a mobile reservoir for transport to sites of growth; ureides perform a similar function in some legumes. Utilisation of transport forms of nitrogen, and a number of other metabolic processes, involves release of ammonia, which must be reassimilated. In illuminated leaves, there is an extensive flux of ammonia released by the photorespiratory cycle, requiring continuous efficient reassimilation. Aspects of ammonia recycling and related amide metabolism in higher plants are reviewed.

Influence of nitrogen source and growth status on glutamine synthetase and glutamate synthase activity in Mycobacterium avium

1985 ◽  
Vol 31 (3) ◽  
pp. 211-213
Author(s):  
Charlotte M. McCarthy ◽  
Maria E. Alvarez
Keyword(s):  
Glutamine Synthetase ◽  
Ammonium Chloride ◽  
Mycobacterium Avium ◽  
Cultured Cells ◽  
Specific Activity ◽  
Glutamate Synthase ◽  
Ammonia Concentration ◽  
Apparent Difference ◽  
Growth Status ◽  
Chloride Concentrations

An investigation was made of the activity of glutamine synthetase and glutamate synthase from batch-cultured cells of Mycobacterium avium. The bacteria were grown in medium with ammonium chloride concentrations of 0, 0.1, 0.25, 1, 5, or 25 μmol/mL or with glutamine at 0.1 or 1 μmol/mL. The specific activity of the two enzymes was determined at 0, 22, 45, and 70 h of incubation. Regardless of the ammonia concentration in the medium, glutamate synthase specific activity was two to five times higher in extracts from elongating cells, incubated 22 h, than in those from shortened cells, incubated 45 or 70 h. In contrast, there was no apparent difference in glutamine synthetase specific activity with regard to culture age; however, glutamine synthetase specific activity varied inversely with the concentration of ammonium chloride in the medium. Cells grown in glutamine had high activity of glutamine synthetase.

Osmoregulation in Rhizobium meliloti: characterization of enzymes involved in glutamate synthesis

1990 ◽  
Vol 36 (7) ◽  
pp. 469-474 ◽  
Author(s):  
Rigoberto Gonzalez-Gonzalez ◽  
James L. Botsford ◽  
Thomas Lewis
Keyword(s):  
Glutamine Synthetase ◽  
Osmotic Stress ◽  
Specific Activity ◽  
Rhizobium Meliloti ◽  
Glutamate Synthase ◽  
The Other ◽  
Glutamine Synthetase Activity ◽  
Biochemical Basis ◽  
Glutamic Dehydrogenase ◽  
Glutamate Synthesis

Rhizobium meliloti, like many bacteria, accumulates elevated levels of glutamate when osmotically stressed. The biochemical basis for this increase in glutamate production was investigated. Enzymes involved in glutamate synthesis, including glutamine synthetase, glutamate synthase, and glutamic dehydrogenase, were characterized in dialyzed crude cell-free extracts. A transaminase activity, which uses branched chain amino acids for the amination of 2-ketoglutaric acid, was also characterized. With the exception of glutamic dehydrogenase, the specific activity of the enzymes did not vary more than 4-fold in response to the available source of nitrogen or supplemental glutamate. Glutamic dehydrogenase activity was 13-fold greater when cells grew with 10 mM [Formula: see text] than when cells grew with 0.5 mM [Formula: see text]. Glutamate synthase was repressed 2-fold when cells grew with supplemental glutamate. Conversely, this enzyme was derepressed 2× when cells grew with 0.5 mM [Formula: see text] or nitrate. Growing cells in minimal defined medium with 400 mM NaCl to cause osmotic stress had little effect on the specific activity of any of the enzymes. The addition of K+ to the reactions stimulated heat-stable glutamine synthetase activity, but inhibited the other enzymes. Glutamate synthase was inhibited to a limited extent by several intermediates in the Krebs' cycle and very severely by glyoxylate. The addition of 10 mM glutamate to the reaction inhibited glutamate synthase 20%, but had no effect on the other enzymes. Key words: enzymes, glutamate synthesis, osmotic stress.

scholarly journals Purification and partial characterization of glutamate synthase from Rhodospirillum rubrum grown under nitrogen-fixing conditions

1991 ◽  
Vol 279 (1) ◽  
pp. 151-154 ◽  
Author(s):  
I Carlberg ◽  
S Nordlund
Keyword(s):  
Metabolic Regulation ◽  
Rhodospirillum Rubrum ◽  
Specific Activity ◽  
Gel Filtration ◽  
Glutamate Synthase ◽  
Photosynthetic Bacterium ◽  
Exchange Chromatography ◽  
Ammonia Assimilation ◽  
Key Enzyme ◽  
Molecular Masses

Glutamate synthase, a key enzyme in ammonia assimilation, has been purified from the photosynthetic bacterium Rhodospirillum rubrum. The purification procedure involves ion-exchange chromatography, affinity chromatography and gel filtration. The recovery in the procedure is high (62%) and the specific activity is 21 mumol of NADPH oxidized/min per mg. The enzyme is specific for its substrates, and no activity was demonstrated with NADH or NH4+ ions substituting for NADPH and glutamine respectively. The enzyme is composed of two dissimilar subunits with molecular masses of 53 and 152 kDa, and it is shown that Cl- ions have an effect on the aggregation of the enzyme. Km values for the substrates are: NADPH, 16 microM; 2-oxoglutarate, 10 microM; and glutamine, 65 microM. The enzyme is inhibited by amidotransferase inhibitors at micromolar concentrations. The role of the enzyme in the metabolic regulation of nitrogenase is discussed.

scholarly journals Physiological and Molecular Osmotic Stress Responses in Three Durum Wheat (Triticum Turgidum ssp Durum) Genotypes

Agronomy ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 550 ◽  
Author(s):  
Salma Jallouli ◽  
Sawsen Ayadi ◽  
Simone Landi ◽  
Giorgia Capasso ◽  
Giorgia Santini ◽  
...  
Keyword(s):  
Glutamine Synthetase ◽  
Osmotic Stress ◽  
Durum Wheat ◽  
Stress Responses ◽  
Triticum Turgidum ◽  
Growth Traits ◽  
Glutamate Synthase ◽  
Dry Weight ◽  
Transcript Abundance ◽  
Primary Metabolism

This study aims to investigate the activities and expression of enzymes of primary metabolism and relate these data with the growth performance of three different durum wheat genotypes (Maali; YT13; and ON66) under osmotic stress. Growth traits—including plant height, dry weight (DW) and relative water content (RWC)—were measured to classify genotypes depending on their tolerance to stress. Several enzymes were investigated: Ascorbate peroxidase (APX), Glutamine Synthetase (GS), Glutamine dehydrogenase (GDH), Glutamate synthase (GOGAT), Glucose 6-phosphate dehydrogenase (G6PDH), and Phosphoenolpyruvate Carboxylase (PEPC). The expression of the cytosolic and plastidic glutamine synthetase (TaGS1 and TaGS2), high affinity nitrate transporters (TaNRT2.3) and Glutamate dehydrogenase (TaGDH) were also detected by qRT-PCR. The results indicated different growth performances among genotypes, indicating Maali and YT13 as tolerant genotypes and ON66 as a drought-susceptible variety. Data showed a decrease in PEPC and increase in APX activities under osmotic stress; a slight decrease in GS activity was observed, together with an increase in G6PDH in all genotypes; GS and NRT2 expressions changed in a similar pattern in the different genotypes. Interestingly, Maali and YT13 showed higher transcript abundance for GDH under stress compared to ON66, suggesting the implication of GDH in protective phenomena upon osmotic stress.

scholarly journals A Tale of Two Families: Whole Genome and Segmental Duplications Underlie Glutamine Synthetase and Phosphoenolpyruvate Carboxylase Diversity in Narrow-Leafed Lupin (Lupinus angustifolius L.)

2020 ◽  
Vol 21 (7) ◽  
pp. 2580 ◽  
Author(s):  
Katarzyna B. Czyż ◽  
Michał Książkiewicz ◽  
Grzegorz Koczyk ◽  
Anna Szczepaniak ◽  
Jan Podkowiński ◽  
...  
Keyword(s):  
Glutamine Synthetase ◽  
Phosphoenolpyruvate Carboxylase ◽  
Higher Plants ◽  
Gene Families ◽  
Lupinus Angustifolius ◽  
Phylogenetic Position ◽  
Primary Metabolism ◽  
Whole Genome ◽  
Segmental Duplications ◽  
The Impact

Narrow-leafed lupin (Lupinus angustifolius L.) has recently been supplied with advanced genomic resources and, as such, has become a well-known model for molecular evolutionary studies within the legume family—a group of plants able to fix nitrogen from the atmosphere. The phylogenetic position of lupins in Papilionoideae and their evolutionary distance to other higher plants facilitates the use of this model species to improve our knowledge on genes involved in nitrogen assimilation and primary metabolism, providing novel contributions to our understanding of the evolutionary history of legumes. In this study, we present a complex characterization of two narrow-leafed lupin gene families—glutamine synthetase (GS) and phosphoenolpyruvate carboxylase (PEPC). We combine a comparative analysis of gene structures and a synteny-based approach with phylogenetic reconstruction and reconciliation of the gene family and species history in order to examine events underlying the extant diversity of both families. Employing the available evidence, we show the impact of duplications on the initial complement of the analyzed gene families within the genistoid clade and posit that the function of duplicates has been largely retained. In terms of a broader perspective, our results concerning GS and PEPC gene families corroborate earlier findings pointing to key whole genome duplication/triplication event(s) affecting the genistoid lineage.

scholarly journals PEPC of sugarcane regulated glutathione S-transferase and altered carbon–nitrogen metabolism under different N source concentrations in Oryza sativa

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Ling Lian ◽  
Yuelong Lin ◽  
Yidong Wei ◽  
Wei He ◽  
Qiuhua Cai ◽  
...  
Keyword(s):  
Nitrogen Metabolism ◽  
Transgenic Rice ◽  
Citrate Synthase ◽  
Higher Plants ◽  
Soluble Sugar ◽  
Glutamate Synthase ◽  
Tca Cycle ◽  
Primary Metabolism ◽  
The Tca Cycle ◽  
Crown Roots

Abstract Background Phosphoenolpyruvate carboxylase (PEPC) plays an important role in the primary metabolism of higher plants. Several studies have revealed the critical importance of PEPC in the interaction of carbon and nitrogen metabolism. However, the function mechanism of PEPC in nitrogen metabolism is unclear and needs further investigation. Results This study indicates that transgenic rice expressing the sugarcane C4-PEPC gene displayed shorter primary roots and fewer crown roots at the seedling stage. However, total nitrogen content was significantly higher in transgenic rice than in wild type (WT) plants. Proteomic analysis revealed that there were more differentially expressed proteins (DEPs) responding to nitrogen changes in transgenic rice. In particular, the most enriched pathway “glutathione (GSH) metabolism”, which mainly contains GSH S-transferase (GST), was identified in transgenic rice. The expression of endogenous PEPC, GST and several genes involved in the TCA cycle, glycolysis and nitrogen assimilation changed in transgenic rice. Correspondingly, the activity of enzymes including GST, citrate synthase, 6-phosphofructokinase, pyruvate kinase and ferredoxin-dependent glutamate synthase significantly changed. In addition, the levels of organic acids in the TCA cycle and carbohydrates including sucrose, starch and soluble sugar altered in transgenic rice under different nitrogen source concentrations. GSH that the substrate of GST and its components including glutamic acid, cysteine and glycine accumulated in transgenic rice. Moreover, the levels of phytohormones including indoleacetic acid (IAA), zeatin (ZT) and isopentenyladenosine (2ip) were lower in the roots of transgenic rice under total nutrients. Taken together, the phenotype, physiological and biochemical characteristics of transgenic rice expressing C4-PEPC were different from WT under different nitrogen levels. Conclusions Our results revealed the possibility that PEPC affects nitrogen metabolism through regulating GST, which provide a new direction and concepts for the further study of the PEPC functional mechanism in nitrogen metabolism.

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