scholarly journals Nitrogen Metabolism of an Anoxygenic Filamentous Phototrophic Bacterium Oscillocholris trichoides Strain DG-6

Microbiology ◽  
2021 ◽  
Vol 90 (4) ◽  
pp. 428-434
Author(s):  
R. N. Ivanovsky ◽  
N. V. Lebedeva ◽  
O. I. Keppen ◽  
T. P. Tourova
Keyword(s):  
Glutamine Synthetase ◽  
Nitrogen Source ◽  
Glutamate Dehydrogenase ◽  
Molecular Nitrogen ◽  
Single Gene ◽  
Nitrogen Sources ◽  
Entire Family ◽  
Ammonium N ◽  
Expression Product ◽  
Typical Strain

Abstract— The possible nitrogen sources for Osc. trichoides DG6, a typical strain of the Oscillochloridaceae family, are ammonium, N2, glutamate, asparagine, glycine, and glutamine. The assimilation of molecular nitrogen occurs with the participation of nitrogenase, the structural gene of which, nifH, is located in the gene cluster which also includes the genes of the nifD and nifK nitrogenase subunits and the auxiliary nifB gene. Considering that nifHBDK clusters have been also annotated in the genomes of other members of the Oscillochloridaceae family, including uncultured and candidate taxa, it can be assumed that the ability to fix nitrogen is a property immanent for this entire family. The pathways for assimilating ammonium in the cells grown using different nitrogen sources may differ. Osc. trichoides DG6 growing in a medium containing ammonium assimilated it with the participation of glutamate dehydrogenase, which is determined by a single gene. The expression product of this gene has dual functionality and can be used to implement the reaction with both NAD and NADP. With the growth of Osc. trichoides DG6 on a medium with glutamate as the only nitrogen source all the enzymes necessary for the implementation of the GS‑GOGAT pathway were found in the cells. However, for the glutamine synthetase reaction, ammonium, which was absent in the growth medium, was required. The source of ammonium may be glutamate metabolized through glutamate dehydrogenase.

scholarly journals Role of the complex upstream region of the GDH2 gene in nitrogen regulation of the NAD-linked glutamate dehydrogenase in Saccharomyces cerevisiae.

1991 ◽  
Vol 11 (12) ◽  
pp. 6229-6247 ◽  
Author(s):  
S M Miller ◽  
B Magasanik
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Glutamine Synthetase ◽  
Nitrogen Source ◽  
Glutamate Dehydrogenase ◽  
Regulatory System ◽  
Sole Source ◽  
Lacz Fusion ◽  
Upstream Region ◽  
In Cells

We analyzed the upstream region of the GDH2 gene, which encodes the NAD-linked glutamate dehydrogenase in Saccharomyces cerevisiae, for elements important for the regulation of the gene by the nitrogen source. The levels of this enzyme are high in cells grown with glutamate as the sole source of nitrogen and low in cells grown with glutamine or ammonium. We found that this regulation occurs at the level of transcription and that a total of six sites are required to cause a CYC1-lacZ fusion to the GDH2 gene to be regulated in the same manner as the NAD-linked glutamate dehydrogenase. Two sites behaved as upstream activation sites (UASs). The remaining four sites were found to block the effects of the two UASs in such a way that the GDH2-CYC1-lacZ fusion was not expressed unless the cells containing it were grown under conditions favorable for the activity of both UASs. This complex regulatory system appears to account for the fact that GDH2 expression is exquisitely sensitive to glutamine, whereas the expression of GLN1, coding for glutamine synthetase, is not nearly as sensitive.

Nitrogen Fixation and the Utilization of Other Inorganic Nitrogen Sources in a Subarctic Lake

1968 ◽  
Vol 25 (10) ◽  
pp. 2101-2110 ◽  
Author(s):  
Vera A. Billaud
Keyword(s):  
Nitrogen Source ◽  
Nitrate Uptake ◽  
Inorganic Nitrogen ◽  
Molecular Nitrogen ◽  
Nitrogen Sources ◽  
Lake Surface ◽  
Interior Alaska ◽  
Uptake Rates ◽  
Tracer Methods ◽  
Subarctic Lake

A year-round limnological study of the biological utilization of molecular nitrogen, ammonia, and nitrate in Smith Lake, a small subarctic lake in interior Alaska, showed that ammonia was consistently the most important nitrogen source. Of the two main algal production periods, the first took place under the ice in May, and depended on ammonia accumulated during the winter for a nitrogen source. The population at this time consisted largely of microflagellates. Chlamydomonas, Euglena, Chlorella, and Mellamonas were among the identified algae present. Immediately after the ice melted from the lake surface, a second population developed. These algae, consisting almost exclusively of Anabaena flos-aquae, used ammonia, nitrate, and molecular nitrogen simultaneously. During the remainder of the summer, uptake rates remained relatively low, with ammonia the most important nitrogen source; during the fall, nitrate uptake briefly approached the magnitude of ammonia uptake. 15N tracer methods were used to measure the uptake rates in this work.

scholarly journals Regulation of synthesis of glutamate dehydrogenase and glutamine synthetase in micro-organisms

1969 ◽  
Vol 115 (4) ◽  
pp. 769-775 ◽  
Author(s):  
J. A. Pateman
Keyword(s):  
Escherichia Coli ◽  
Glutamine Synthetase ◽  
Glutamate Dehydrogenase ◽  
Nitrogen Sources ◽  
Sole Source ◽  
Synthetase Activity ◽  
Glutamine Synthetase Activity ◽  
Escherichia Coli Cells ◽  
High Concentrations ◽  
Micro Organisms

1. Aspergillus nidulans, Neurospora crassa and Escherichia coli were grown on media containing a range of concentrations of nitrate, or ammonia, or urea, or l-glutamate, or l-glutamine as the sole source of nitrogen and the glutamate dehydrogenate and glutamine synthetase of the cells measured. 2. Aspergillus, Neurospora and Escherichia coli cells, grown on l-glutamate or on high concentrations of ammonia or on high concentrations of urea, possessed low glutamate dehydrogenase activity compared with cells grown on other nitrogen sources. 3. Aspergillus, Neurospora and Escherichia coli cells grown on l-glutamate possessed high glutamine synthetase activity compared with cells grown on other nitrogen sources. 4. The hypothesis is proposed that in Aspergillus, Neurospora and Escherichia colil-glutamate represses the synthesis of glutamate dehydrogenase and l-glutamine represses the synthesis of glutamine synthetase. 5. A comparison of the glutamine-synthesizing activity and the γ-glutamyltransferase activity of glutamine synthetase in Aspergillus and Neurospora gave no indication that these fungi produce different forms of glutamine synthetase when grown on ammonia or l-glutamate as nitrogen sources.

Boron deficiency increases expressions of asparagine synthetase, glutamate dehydrogenase and glutamine synthetase genes in tobacco roots irrespective of the nitrogen source

2014 ◽  
Vol 60 (3) ◽  
pp. 314-324 ◽  
Author(s):  
Víctor M. Beato ◽  
Jesús Rexach ◽  
M. Teresa Navarro-Gochicoa ◽  
Juan J. Camacho-Cristóbal ◽  
M. Begoña Herrera-Rodríguez ◽  
...  
Keyword(s):  
Glutamine Synthetase ◽  
Nitrogen Source ◽  
Glutamate Dehydrogenase ◽  
Asparagine Synthetase ◽  
Boron Deficiency ◽  
Tobacco Roots

scholarly journals Effects of Nitrogen and Carbon Sources on Transcription of Soluble Methyltransferases in Methanosarcina mazei Strain Gö1

2005 ◽  
Vol 187 (17) ◽  
pp. 6147-6154 ◽  
Author(s):  
Katharina Veit ◽  
Claudia Ehlers ◽  
Ruth A. Schmitz
Keyword(s):  
Nitrogen Source ◽  
Degradation Products ◽  
Molecular Nitrogen ◽  
Carbon Sources ◽  
Nitrogen Sources ◽  
Initial Step ◽  
Conclusive Evidence ◽  
Carbon And Nitrogen ◽  
Methanosarcina Mazei ◽  
Or Genes

ABSTRACT The methanogenic archaeon Methanosarcina mazei strain Gö1 uses versatile carbon sources and is able to fix molecular nitrogen with methanol as carbon and energy sources. Here, we demonstrate that when growing on trimethylamine (TMA), nitrogen fixation does not occur, indicating that ammonium released during TMA degradation is sufficient to serve as a nitrogen source and represses nif gene induction. We further report on the transcriptional regulation of soluble methyltransferases, which catalyze the initial step of methylamine consumption by methanogenesis, in response to different carbon and nitrogen sources. Unexpectedly, we obtained conclusive evidence that transcription of the mtmB2C2 operon, encoding a monomethylamine (MMA) methyltransferase and its corresponding corrinoid protein, is highly increased under nitrogen limitation when methanol serves as a carbon source. In contrast, transcription of the homologous mtmB1C1 operon is not affected by the nitrogen source but appears to be increased when TMA is the sole carbon and energy source. In general, transcription of operons encoding dimethylamine (DMA) and TMA methyltransferases and methylcobalamine:coenzyme M methyltransferases is not regulated in response to the nitrogen source. However, in all cases transcription of one of the homologous operons or genes is increased by TMA or its degradation products DMA and MMA.

scholarly journals Effect of Nitrogen Source on Growth and Trichloroethylene Degradation by Methane-Oxidizing Bacteria

1998 ◽  
Vol 64 (9) ◽  
pp. 3451-3457 ◽  
Author(s):  
Kung-Hui Chu ◽  
Lisa Alvarez-Cohen
Keyword(s):  
Nitrogen Source ◽  
Chemostat Culture ◽  
Molecular Nitrogen ◽  
Nitrogen Sources ◽  
Cellular Growth ◽  
Nitrogen Fixing ◽  
External Energy ◽  
Oxidation Rates ◽  
Methane Oxidizing Bacteria ◽  
Tce Degradation

ABSTRACT The effect of nitrogen source on methane-oxidizing bacteria with respect to cellular growth and trichloroethylene (TCE) degradation ability were examined. One mixed chemostat culture and two pure type II methane-oxidizing strains, Methylosinus trichosporium OB3b and strain CAC-2, which was isolated from the chemostat culture, were used in this study. All cultures were able to grow with each of three different nitrogen sources: ammonia, nitrate, and molecular nitrogen. Both M. trichosporium OB3b and strain CAC-2 showed slightly lower net cellular growth rates and cell yields but exhibited higher methane uptake rates, levels of poly-β-hydroxybutyrate (PHB) production, and naphthalene oxidation rates when grown under nitrogen-fixing conditions. The TCE-degrading ability of each culture was measured in terms of initial TCE oxidation rates and TCE transformation capacities (mass of TCE degraded/biomass inactivated), measured both with and without external energy sources. Higher initial TCE oxidation rates and TCE transformation capacities were observed in nitrogen-fixing mixed, M. trichosporium OB3b, and CAC-2 cultures than in nitrate- or ammonia-supplied cells. TCE transformation capacities were found to correlate with cellular PHB content in all three cultures. The results of this study suggest that the nitrogen-fixing capabilities of methane-oxidizing bacteria can be used to select for high-activity TCE degraders for the enhancement of bioremediation in fixed-nitrogen-limited environments.

Regulation of ammonia-assimilating enzymes by various nitrogen sources in cultured Ipomoea spp.

1989 ◽  
Vol 67 (11) ◽  
pp. 3127-3133 ◽  
Author(s):  
M. W. Zink
Keyword(s):  
Glutamine Synthetase ◽  
Glutamate Dehydrogenase ◽  
Growth Medium ◽  
Glutamate Synthase ◽  
Nitrogen Sources ◽  
Defined Medium ◽  
Morning Glory ◽  
Synthetase Activity ◽  
Glutamine Synthetase Activity ◽  
Chemically Defined Medium

The levels of ammonia-assimilating enzymes of Ipomoea spp. (morning glory) grown in suspension culture on a chemically defined medium are affected by various nitrogen sources. An increase in nitrate or ammonium concentrations in the growth medium elevated the levels of glutamate dehydrogenase, glutamine synthetase, and glutamate synthase. The levels of the enzymes varied in a manner similar to the growth pattern of the cells. When the growth rate of Ipomoea was maximal, high levels of enzymes were obtained; when cell growth was poor, a low yield of enzymes was obtained. Glutamine, whether used as the sole nitrogen source or as a supplement in media containing ammonium plus nitrate, increased the level of glutamate dehydrogenase and decreased the level of the other two enzymes. The developmental pattern of glutamine synthetase activity with culture age in Ipomoea differed with different nitrogen sources in the growth medium.

Role of the complex upstream region of the GDH2 gene in nitrogen regulation of the NAD-linked glutamate dehydrogenase in Saccharomyces cerevisiae

1991 ◽  
Vol 11 (12) ◽  
pp. 6229-6247
Author(s):  
S M Miller ◽  
B Magasanik
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Glutamine Synthetase ◽  
Nitrogen Source ◽  
Glutamate Dehydrogenase ◽  
Regulatory System ◽  
Sole Source ◽  
Lacz Fusion ◽  
Upstream Region ◽  
In Cells

We analyzed the upstream region of the GDH2 gene, which encodes the NAD-linked glutamate dehydrogenase in Saccharomyces cerevisiae, for elements important for the regulation of the gene by the nitrogen source. The levels of this enzyme are high in cells grown with glutamate as the sole source of nitrogen and low in cells grown with glutamine or ammonium. We found that this regulation occurs at the level of transcription and that a total of six sites are required to cause a CYC1-lacZ fusion to the GDH2 gene to be regulated in the same manner as the NAD-linked glutamate dehydrogenase. Two sites behaved as upstream activation sites (UASs). The remaining four sites were found to block the effects of the two UASs in such a way that the GDH2-CYC1-lacZ fusion was not expressed unless the cells containing it were grown under conditions favorable for the activity of both UASs. This complex regulatory system appears to account for the fact that GDH2 expression is exquisitely sensitive to glutamine, whereas the expression of GLN1, coding for glutamine synthetase, is not nearly as sensitive.

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