L-Glutamine metabolism and its regulation in C. glutamicum
Ontology highlight
ABSTRACT:
ORGANISM(S): Corynebacterium glutamicum ATCC 13032
PROVIDER: GSE19779 | GEO | 2010/10/05
SECONDARY ACCESSION(S): PRJNA121865
REPOSITORIES: GEO
Similar Datasets
Project description:Corynebacterium glutamicum, a gram-positive soil bacterium used for the industrial production of amino acids such as L-glutamate and L-lysine, is able to use a number of different nitrogen sources, such as ammonium, urea, or creatinine. In this communication, we show that L-glutamine serves as an excellent nitrogen source for C. glutamicum and allows similar growth rates in glucose minimal medium as ammonium. A transcriptome comparison revealed a strong induction of the nitrogen starvation response when glutamine was used as nitrogen source. Subsequent growth experiments with a variety of mutants defective in nitrogen metabolism showed that glutamate synthase is crucial for glutamine utilization, while a putative glutaminase is dispensable under the experimental conditions used. The fact that the glutamate synthase encoding gltBD operon is under strict nitrogen control explains the necessity for induction of the nitrogen starvation response. The paradox situation that the nitrogen starvation response is induced although intracellular L-glutamine levels are high has implications on nitrogen sensing. In contrast to other gram-positive and gram-negative bacteria such as Bacillus subtilis, Salmonella typhimurium, and Klebsiella pneumoniae, a drop in glutamine concentration obviously does not serve as a nitrogen starvation signal in C. glutamicum. Three biological replicates were performed. To analyse how L-glutamine influences global gene expression when used as sole nitrogen source instead of ammonium, DNA microarray analyses were performed. For this purpose RNA was isolated from exponentially growing cells cultivated in CgXII medium containing glucose as carbon source and either L-glutamine or ammonium sulphate as nitrogen source.
2010-10-05 | E-GEOD-19779 | biostudies-arrayexpress
Project description:The influence of different nitrogen sources on transcriptome of Purple non sulfur bacterium R. Capsulatus was investigated by comparing expression profile on 5mM ammonium chloride and 2 mM glutamate. Carbon source was 40mM acetate on both conditions. To study the effect of different acetate concentrations, 40mM and 80mM acetate were used with 2 mM glutamate as nitrogen source.
2013-12-14 | GSE53303 | GEO
Project description:Transcriptional profiling of Haloferax mediterranei in three culture media with different nitrogen sources: a) cells were grown stationary and exponentially on ammonium, b) cells were grown exponentially on nitrate, and c) cells were shifted to nitrogen starvation conditions. The main differences in the transcriptional profiles have been identified between the cultures with ammonium as nitrogen source and the cultures with nitrate or nitrogen starvation, supporting previous results which indicate the absence of ammonium as the factor causing the expression of genes involved in nitrate assimilation pathway.
2016-07-01 | GSE59551 | GEO
Project description:Several genes involved in nitrogen metabolism are known to contribute to the virulence of pathogenic bacteria. Here, we studied the function of the nitrogen regulatory protein GlnR in the Gram-positive human pathogen Streptococcus pneumoniae. We demonstrate that GlnR mediates transcriptional repression of genes involved in glutamine synthesis and uptake (glnA, glnPQ), glutamate synthesis (gdhA), and the gene encoding the pentose phosphate pathway enzyme Zwf, which forms an operon with glnPQ. Moreover, the expression of gdhA is also repressed by the pleiotropic regulator CodY. The GlnR-dependent regulation occurs through a conserved operator sequence and is responsive to the concentration of glutamate, glutamine and ammonium in the growth medium. By means of in vitro binding studies and transcriptional analyses we show that the regulatory function of GlnR is dependent on GlnA. Mutants of glnA and glnP displayed significantly reduced adhesion to Detroit 562 human pharyngeal epithelial cells, suggesting a role for these genes in the colonization of the host by S. pneumoniae. Thus, our results provide a thorough insight into the regulation of glutamine and glutamate metabolism of S. pneumoniae as mediated by both GlnR and GlnA. Keywords: genetic modification
2006-06-23 | GSE5088 | GEO
Project description:Rice grown in paddy fields prefers to use ammonium ions as a major source of inorganic nitrogen. Glutamine synthetase (GS) catalyzes the conversion of ammonium ions to glutamine. In three cytosolic GS in rice, OsGS1;1 has the critical role for normal growth and grain filling. To understand a role of GS1;1, we performed transcriptional profiling of wild type Nipponbare and GS1;1 mutant plants in seedling using the Agilent Rice Oligo Microarray.
2010-03-01 | GSE15122 | GEO
Project description:Algal biofuel production requires an input of synthetic nitrogen fertilizer. Fertilizer synthesized via the Haber-Bosch process produces CO2 as a waste by-product and represents a substantial financial and energy investment. Reliance on synthetic fertilizer attenuates the environmental significance and economic viability of algae production systems. To lower fertilizer input, the waste streams of algal production systems can be recycled to provide alternative sources of nitrogen such as amino acids to the algae. The halophytic green alga Dunaliella viridis can use ammonium (NH4+) derived from the abiotic degradation of amino acids, and previously, supplementation of NH4+ from glutamine (GLN) degradation was shown to support acceptable levels of growth and increased neutral lipid production compared to nitrate. To understand the effect of glutamine-released NH4+ on algae growth and physiology, metabolite levels, growth parameters, and transcript profiles of D. viridis cultures were observed in a time course after transition from media containing nitrate as a sole N source to medium containing GLN, glutamate (GLU), or a N-depleted medium. Growth parameters were similar between GLN (NH4+) and nitrate supplemented cultures, however, metabolite data showed that the GLN supplemented cultures (NH4+) more closely resembled cultures under nitrogen starvation (N-depleted and GLU supplementation). Neutral lipid accumulation was the same in nitrate and glutamine-derived NH4+ cultures. However, glutamine-derived NH4+ caused a transcriptional response in the immediate hours after inoculation of the culture. The strong initial response of cultures to NH4+ changed over the course of days to closely resemble that of nitrogen starvation. These observations suggest that release of NH4+ from glutamine was sufficient to maintain growth, but not high enough to trigger a cell transition to a nitrogen replete state. Comparative transcript profiling of the nitrogen-starved and nitrate-supplied cultures show an overall downregulation of fatty acid synthesis and a shift to starch synthesis and accumulation. The results indicate that a continuous, amino acid derived slow release of NH4+ to algae cultures could reduce the amount of synthetic nitrogen needed for growth, but optimization is needed to balance nitrogen starvation and cell division.
2018-03-30 | GSE111548 | GEO
Project description:This a model from the article:
The multifarious short-term regulation of ammonium assimilation of Escherichia coli: dissection using an in silico replica.
Bruggeman FJ, Boogerd FC, Westerhoff HV. FEBS J.
2005 Apr;272(8):1965-85. 15819889
,
Abstract:
Ammonium assimilation in Escherichia coli is regulated through multiple mechanisms (metabolic, signal transduction leading to covalent modification, transcription, and translation), which (in-)directly affect the activities of its two ammonium-assimilating enzymes, i.e. glutamine synthetase (GS) and glutamate dehydrogenase (GDH). Much is known about the kinetic properties of the components of the regulatory network that these enzymes are part of, but the ways in which, and the extents to which the network leads to subtle and quasi-intelligent regulation are unappreciated. To determine whether our present knowledge of the interactions between and the kinetic properties of the components of this network is complete - to the extent that when integrated in a kinetic model it suffices to calculate observed physiological behaviour - we now construct a kinetic model of this network, based on all of the kinetic data on the components that is available in the literature. We use this model to analyse regulation of ammonium assimilation at various carbon statuses for cells that have adapted to low and high ammonium concentrations. We show how a sudden increase in ammonium availability brings about a rapid redirection of the ammonium assimilation flux from GS/glutamate synthase (GOGAT) to GDH. The extent of redistribution depends on the nitrogen and carbon status of the cell. We develop a method to quantify the relative importance of the various regulators in the network. We find the importance is shared among regulators. We confirm that the adenylylation state of GS is the major regulator but that a total of 40% of the regulation is mediated by ADP (22%), glutamate (10%), glutamine (7%) and ATP (1%). The total steady-state ammonium assimilation flux is remarkably robust against changes in the ammonium concentration, but the fluxes through GS and GDH are completely nonrobust. Gene expression of GOGAT above a threshold value makes expression of GS under ammonium-limited conditions, and of GDH under glucose-limited conditions, sufficient for ammonium assimilation.
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2024-09-02 | BIOMD0000000217 | BioModels
Project description:To screen the genes related to nitrogen use efficiency, a Chinese fir clone named X6 was subjected to low nitrogen (LN) stress and was used along with control (CK) plants for de novo RNA sequencing of root transcriptomes. The differences in the expression of genes under both conditions were determined. A total of 4,300 significant differentially expressed genes (SDEGs) were obtained by comparing the transcriptomes of the plants in the LN and CK groups. Among these genes, 2,970 were upregulated, and 1,330 were downregulated. All the SDEGs obtained from the LN and CK samples were subjected to KEGG annotation and classification. Using classification and statistical analysis with WEGO software, KEGG pathway annotations were obtained for 980 SDEGs, which were related to 222 metabolic pathways, and the pathway for nitrogen metabolism was determined. Twenty-four unigenes related to nitrogen metabolism in the Chinese fir were screened. They were found to encode seven enzymes: nitrate reductase (NADH, NR1), ferredoxin-nitrite reductase (NIR1), glutamine synthetase (GS), glutamate synthase (ferredoxin; Fd-GOGAT), glutamate synthase (NADPH/NADH, NADH-GOGAT), glutamate dehydrogenase (NADP+, GDH1), and glutamate dehydrogenase (NAD(P)+,GDH2), as well as two transporters, namely, ammonium transporter (AMT) and nitrate transporter (NRT). Under nitrogen-deficient conditions, AMT, NRT, NR1, and GS were significantly upregulated, whereas NIR1, NADH-GOGAT, and GDH2 were significantly downregulated; the other genes showed no significant changes. This is the first report on the global transcriptome response of the Chinese fir to nitrogen deficiency. Our results might help illustrate the preference of the Chinese fir for NH4+ rather than for NO3−. Our data provide insights into the coordinated system of nitrogen metabolism in this valuable tree species.
2019-04-03 | GSE117392 | GEO
Project description:The tumor microenvironment (TME) contains a rich source of nutrients that sustain cell growth and ultimately facilitate tumor progression. The availability of glucose and glutamine in the TME are essential for the development and activation of effector T cells that exert anti-tumor function. Recently, inhibition of glutaminase, the enzyme that hydrolyzes glutamine to glutamate, has garnered interest as an approach to both decrease tumor metabolism and growth, while increasing available glutamine in the TME for effector T cells. Checkpoint blockade immunotherapy unleashes anti-tumor effector capabilities of T cells, and although there are good responses in many solid tumors, a significant proportion of patients respond poorly. In lung adenocarcinoma, response to immunotherapy is reported to be impaired in KRAS-mutant patients harboring concurrent KEAP1 and STK11/Lkb1 mutations. To investigate the metabolism and immune microenvironment of KRAS-mutant lung adenocarcinoma, we generated a series of murine models that reflect the KEAP1 and STK11/Lkb1 mutational landscape seen in patients. Here we show increased glutamate abundance in the Lkb1-deficient TME associated with CD8 T cell activation in response to anti-PD1 checkpoint immunotherapy. Combination treatment with the glutaminase inhibitor CB-839 inhibited clonal expansion and cytotoxic activation of tumor-infiltrating CD8 T cells. Thus, CD8 T cells exposed to checkpoint immunotherapy have a dependence on glutamine and reliance on glutaminase activity and are negatively impacted by the glutaminase inhibitor in this highly activated state. Therefore, we discern that the combination of immunotherapy and glutaminase inhibition is not efficacious for CD8 T cell activation in the tumor microenvironment.
2022-05-02 | GSE193895 | GEO
Project description:Several genes involved in nitrogen metabolism are known to contribute to the virulence of pathogenic bacteria. Here, we studied the function of the nitrogen regulatory protein GlnR in the Gram-positive human pathogen Streptococcus pneumoniae. We demonstrate that GlnR mediates transcriptional repression of genes involved in glutamine synthesis and uptake (glnA, glnPQ), glutamate synthesis (gdhA), and the gene encoding the pentose phosphate pathway enzyme Zwf, which forms an operon with glnPQ. Moreover, the expression of gdhA is also repressed by the pleiotropic regulator CodY. The GlnR-dependent regulation occurs through a conserved operator sequence and is responsive to the concentration of glutamate, glutamine and ammonium in the growth medium. By means of in vitro binding studies and transcriptional analyses we show that the regulatory function of GlnR is dependent on GlnA. Mutants of glnA and glnP displayed significantly reduced adhesion to Detroit 562 human pharyngeal epithelial cells, suggesting a role for these genes in the colonization of the host by S. pneumoniae. Thus, our results provide a thorough insight into the regulation of glutamine and glutamate metabolism of S. pneumoniae as mediated by both GlnR and GlnA. Each amplicon was spotted twice (technical replicates) on the DNA microarray. These replicates are indicated in the platforms and DNA microarray data by the addition of _rep1, _rep2, etc. The RNA for wild-type and mutant strains was isolated in 3 independent biological replicates which were hybridized in (partly dye-swap) to the 3 slides for glnA and 3 slides for glnR.
2010-07-01 | E-GEOD-5088 | biostudies-arrayexpress