scholarly journals Metabolic Changes Induced by Deletion of Transcriptional Regulator GCR2 in Xylose-Fermenting Saccharomyces cerevisiae

2020 ◽  
Vol 8 (10) ◽  
pp. 1499
Author(s):  
Minhye Shin ◽  
Soo Rin Kim
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Carbon Source ◽  
Pentose Phosphate Pathway ◽  
Carbon Metabolism ◽  
Transcriptional Regulator ◽  
Central Carbon Metabolism ◽  
Pentose Phosphate ◽  
Metabolic Changes ◽  
Regulatory Systems ◽  
Central Carbon

Glucose repression has been extensively studied in Saccharomyces cerevisiae, including the regulatory systems responsible for efficient catabolism of glucose, the preferred carbon source. However, how these regulatory systems would alter central metabolism if new foreign pathways are introduced is unknown, and the regulatory networks between glycolysis and the pentose phosphate pathway, the two major pathways in central carbon metabolism, have not been systematically investigated. Here we disrupted gcr2, a key transcriptional regulator, in S. cerevisiae strain SR7 engineered to heterologously express the xylose-assimilating pathway, activating genes involved in glycolysis, and evaluated the global metabolic changes. gcr2 deletion reduced cellular growth in glucose but significantly increased growth when xylose was the sole carbon source. Global metabolite profiling revealed differential regulation of yeast metabolism in SR7-gcr2Δ, especially carbohydrate and nucleotide metabolism, depending on the carbon source. In glucose, the SR7-gcr2Δ mutant showed overall decreased abundance of metabolites, such as pyruvate and sedoheptulose-7-phosphate, associated with central carbon metabolism including glycolysis and the pentose phosphate pathway. However, SR7-gcr2Δ showed an increase in metabolites abundance (ribulose-5-phosphate, sedoheptulose-7-phosphate, and erythrose-4-phosphate) notably from the pentose phosphate pathway, as well as alteration in global metabolism when compared to SR7. These results provide insights into how the regulatory system GCR2 coordinates the transcription of glycolytic genes and associated metabolic pathways.

scholarly journals The Metabolite Repair Enzyme Phosphoglycolate Phosphatase Regulates Central Carbon Metabolism and Fosmidomycin Sensitivity in Plasmodium falciparum

mBio ◽  
2019 ◽  
Vol 10 (6) ◽  
Author(s):  
Laure Dumont ◽  
Mark B. Richardson ◽  
Phillip van der Peet ◽  
Danushka S. Marapana ◽  
Tony Triglia ◽  
...  
Keyword(s):  
Pentose Phosphate Pathway ◽  
Carbon Metabolism ◽  
Central Carbon Metabolism ◽  
Pentose Phosphate ◽  
Repair Enzyme ◽  
Content Type ◽  
Phosphoglycolate Phosphatase ◽  
Central Carbon ◽  
Metabolite Repair ◽  
By Products

ABSTRACT Members of the haloacid dehalogenase (HAD) family of metabolite phosphatases play an important role in regulating multiple pathways in Plasmodium falciparum central carbon metabolism. We show that the P. falciparum HAD protein, phosphoglycolate phosphatase (PGP), regulates glycolysis and pentose pathway flux in asexual blood stages via detoxifying the damaged metabolite 4-phosphoerythronate (4-PE). Disruption of the P. falciparum pgp gene caused accumulation of two previously uncharacterized metabolites, 2-phospholactate and 4-PE. 4-PE is a putative side product of the glycolytic enzyme, glyceraldehyde-3-phosphate dehydrogenase, and its accumulation inhibits the pentose phosphate pathway enzyme, 6-phosphogluconate dehydrogenase (6-PGD). Inhibition of 6-PGD by 4-PE leads to an unexpected feedback response that includes increased flux into the pentose phosphate pathway as a result of partial inhibition of upper glycolysis, with concomitant increased sensitivity to antimalarials that target pathways downstream of glycolysis. These results highlight the role of metabolite detoxification in regulating central carbon metabolism and drug sensitivity of the malaria parasite. IMPORTANCE The malaria parasite has a voracious appetite, requiring large amounts of glucose and nutrients for its rapid growth and proliferation inside human red blood cells. The host cell is resource rich, but this is a double-edged sword; nutrient excess can lead to undesirable metabolic reactions and harmful by-products. Here, we demonstrate that the parasite possesses a metabolite repair enzyme (PGP) that suppresses harmful metabolic by-products (via substrate dephosphorylation) and allows the parasite to maintain central carbon metabolism. Loss of PGP leads to the accumulation of two damaged metabolites and causes a domino effect of metabolic dysregulation. Accumulation of one damaged metabolite inhibits an essential enzyme in the pentose phosphate pathway, leading to substrate accumulation and secondary inhibition of glycolysis. This work highlights how the parasite coordinates metabolic flux by eliminating harmful metabolic by-products to ensure rapid proliferation in its resource-rich niche.

scholarly journals Characterization of Mutations That Affect the Nonoxidative Pentose Phosphate Pathway in Sinorhizobium meliloti

2017 ◽  
Vol 200 (2) ◽  
Author(s):  
Justin P. Hawkins ◽  
Patricia A. Ordonez ◽  
Ivan J. Oresnik
Keyword(s):  
Nitrogen Fixation ◽  
Mutant Strain ◽  
Pentose Phosphate Pathway ◽  
Carbon Metabolism ◽  
Sinorhizobium Meliloti ◽  
Iron Acquisition ◽  
Central Carbon Metabolism ◽  
Pentose Phosphate ◽  
Content Type ◽  
Central Carbon

ABSTRACTSinorhizobium melilotiis a Gram-negative alphaproteobacterium that can enter into a symbiotic relationship withMedicago sativaandMedicago truncatula. Previous work determined that a mutation in thetkt2gene, which encodes a putative transketolase, could prevent medium acidification associated with a mutant strain unable to metabolize galactose. Since the pentose phosphate pathway inS. melilotiis not well studied, strains carrying mutations in eithertkt2andtal, which encodes a putative transaldolase, were characterized. Carbon metabolism phenotypes revealed that both mutants were impaired in growth on erythritol and ribose. This phenotype was more pronounced for thetkt2mutant strain, which also displayed auxotrophy for aromatic amino acids. Changes in pentose phosphate pathway metabolite concentrations were also consistent with a mutation in eithertkt2ortal. The concentrations of metabolites in central carbon metabolism were also found to shift dramatically in strains carrying atkt2mutation. While the concentrations of proteins involved in central carbon metabolism did not change significantly under any conditions, the levels of those associated with iron acquisition increased in the wild-type strain with erythritol induction. These proteins were not detected in either mutant, resulting in less observable rhizobactin production in thetkt2mutant. While both mutants were impaired in succinoglycan synthesis, only thetkt2mutant strain was unable to establish symbiosis with alfalfa. These results suggest thattkt2andtalplay central roles in regulating the carbon flow necessary for carbon metabolism and the establishment of symbiosis.IMPORTANCESinorhizobium melilotiis a model organism for the study of plant-microbe interactions and metabolism, especially because it effects nitrogen fixation. The ability to derive the energy necessary for nitrogen fixation is dependent on an organism's ability to metabolize carbon efficiently. The pentose phosphate pathway is central in the interconversion of hexoses and pentoses. This study characterizes the key enzymes of the nonoxidative branch of the pentose phosphate pathway by using defined genetic mutations and shows the effects the mutations have on the metabolite profile and on physiological processes such as the biosynthesis of exopolysaccharide, as well as the ability to regulate iron acquisition.

scholarly journals HexR Controls Glucose-Responsive Genes and Central Carbon Metabolism in Neisseria meningitidis

2015 ◽  
Vol 198 (4) ◽  
pp. 644-654 ◽  
Author(s):  
Ana Antunes ◽  
Giacomo Golfieri ◽  
Francesca Ferlicca ◽  
Marzia M. Giuliani ◽  
Vincenzo Scarlato ◽  
...  
Keyword(s):  
Energy Metabolism ◽  
Neisseria Meningitidis ◽  
Microarray Analysis ◽  
Carbon Metabolism ◽  
Tricarboxylic Acid Cycle ◽  
Transcriptional Regulator ◽  
Central Carbon Metabolism ◽  
Binding Motif ◽  
Content Type ◽  
Central Carbon

ABSTRACTNeisseria meningitidis, an exclusively human pathogen and the leading cause of bacterial meningitis, must adapt to different host niches during human infection.N. meningitidiscan utilize a restricted range of carbon sources, including lactate, glucose, and pyruvate, whose concentrations vary in host niches. Microarray analysis ofN. meningitidisgrown in a chemically defined medium in the presence or absence of glucose allowed us to identify genes regulated by carbon source availability. Most such genes are implicated in energy metabolism and transport, and some are implicated in virulence. In particular, genes involved in glucose catabolism were upregulated, whereas genes involved in the tricarboxylic acid cycle were downregulated. Several genes encoding surface-exposed proteins, including the MafA adhesins andNeisseriasurface protein A, were upregulated in the presence of glucose. Our microarray analysis led to the identification of a glucose-responsivehexR-like transcriptional regulator that controls genes of the central carbon metabolism ofN. meningitidisin response to glucose. We characterized the HexR regulon and showed that thehexRgene is accountable for some of the glucose-responsive regulation;in vitroassays with the purified protein showed that HexR binds to the promoters of the central metabolic operons of the bacterium. Based on DNA sequence alignment of the target sites, we propose a 17-bp pseudopalindromic consensus HexR binding motif. Furthermore,N. meningitidisstrains lackinghexRexpression were deficient in establishing successful bacteremia in an infant rat model of infection, indicating the importance of this regulator for the survival of this pathogenin vivo.IMPORTANCENeisseria meningitidisgrows on a limited range of nutrients during infection. We analyzed the gene expression ofN. meningitidisin response to glucose, the main energy source available in human blood, and we found that glucose regulates many genes implicated in energy metabolism and nutrient transport, as well as some implicated in virulence. We identified and characterized a transcriptional regulator (HexR) that controls metabolic genes ofN. meningitidisin response to glucose. We generated a mutant lacking HexR and found that the mutant was impaired in causing systemic infection in animal models. SinceN. meningitidislacks known bacterial regulators of energy metabolism, our findings suggest that HexR plays a major role in its biology by regulating metabolism in response to environmental signals.

scholarly journals YvcK of Bacillus subtilis is required for a normal cell shape and for growth on Krebs cycle intermediates and substrates of the pentose phosphate pathway

Microbiology ◽  
2005 ◽  
Vol 151 (11) ◽  
pp. 3777-3791 ◽  
Author(s):  
Boris Görke ◽  
Elodie Foulquier ◽  
Anne Galinier
Keyword(s):  
Bacillus Subtilis ◽  
Pentose Phosphate Pathway ◽  
Carbon Metabolism ◽  
Carbon Sources ◽  
Krebs Cycle ◽  
Normal Growth ◽  
Central Carbon Metabolism ◽  
Pentose Phosphate ◽  
Homologous Protein ◽  
Krebs Cycle Intermediates

The HPr-like protein Crh has so far been detected only in the bacillus group of bacteria. In Bacillus subtilis, its gene is part of an operon composed of six ORFs, three of which exhibit strong similarity to genes of unknown function present in many bacteria. The promoter of the operon was determined and found to be constitutively active. A deletion analysis revealed that gene yvcK, encoded by this operon, is essential for growth on Krebs cycle intermediates and on carbon sources metabolized via the pentose phosphate pathway. In addition, cells lacking YvcK acquired media-dependent filamentous or L-shape-like aberrant morphologies. The presence of high magnesium concentrations restored normal growth and cell morphology. Furthermore, suppressor mutants cured from these growth defects appeared spontaneously with a high frequency. Such suppressing mutations were identified in a transposon mutagenesis screen and found to reside in seven different loci. Two of them mapped in genes of central carbon metabolism, including zwf, which encodes glucose-6-phosphate dehydrogenase and cggR, the product of which regulates the synthesis of glyceraldehyde-3-phosphate dehydrogenase. All these results suggest that YvcK has an important role in carbon metabolism, probably in gluconeogenesis required for the synthesis of cell wall precursor molecules. Interestingly, the Escherichia coli homologous protein, YbhK, can substitute for YvcK in B. subtilis, suggesting that the two proteins have been functionally conserved in these different bacteria.

scholarly journals Comparative metabolomics of Phialemonium curvatum as an omnipotent fungus cultivated on crude palm oil versus glucose

2020 ◽  
Vol 19 (1) ◽  
Author(s):  
Arief Izzairy Zamani ◽  
Susann Barig ◽  
Sarah Ibrahim ◽  
Hirzun Mohd. Yusof ◽  
Julia Ibrahim ◽  
...  
Keyword(s):  
Carbon Source ◽  
Organic Acids ◽  
Vegetable Oil ◽  
Carbon Metabolism ◽  
Sole Carbon Source ◽  
Carbon Sources ◽  
Tca Cycle ◽  
Central Carbon Metabolism ◽  
Targeted Metabolomics ◽  
Central Carbon

Abstract Background Sugars and triglycerides are common carbon sources for microorganisms. Nonetheless, a systematic comparative interpretation of metabolic changes upon vegetable oil or glucose as sole carbon source is still lacking. Selected fungi that can grow in acidic mineral salt media (MSM) with vegetable oil had been identified recently. Hence, this study aimed to investigate the overall metabolite changes of an omnipotent fungus and to reveal changes at central carbon metabolism corresponding to both carbon sources. Results Targeted and non-targeted metabolomics for both polar and semi-polar metabolites of Phialemonium curvatum AWO2 (DSM 23903) cultivated in MSM with palm oil (MSM-P) or glucose (MSM-G) as carbon sources were obtained. Targeted metabolomics on central carbon metabolism of tricarboxylic acid (TCA) cycle and glyoxylate cycle were analysed using LC–MS/MS-TripleQ and GC–MS, while untargeted metabolite profiling was performed using LC–MS/MS-QTOF followed by multivariate analysis. Targeted metabolomics analysis showed that glyoxylate pathway and TCA cycle were recruited at central carbon metabolism for triglyceride and glucose catabolism, respectively. Significant differences in organic acids concentration of about 4- to 8-fold were observed for citric acid, succinic acid, malic acid, and oxaloacetic acid. Correlation of organic acids concentration and key enzymes involved in the central carbon metabolism was further determined by enzymatic assays. On the other hand, the untargeted profiling revealed seven metabolites undergoing significant changes between MSM-P and MSM-G cultures. Conclusions Overall, this study has provided insights on the understanding on the effect of triglycerides and sugar as carbon source in fungi global metabolic pathway, which might become important for future optimization of carbon flux engineering in fungi to improve organic acids production when vegetable oil is applied as the sole carbon source.

Rewiring central carbon metabolism for tyrosol and salidroside production in Saccharomyces cerevisiae

2020 ◽  
Vol 117 (8) ◽  
pp. 2410-2419 ◽  
Author(s):  
Wei Guo ◽  
Qiulan Huang ◽  
Yuhui Feng ◽  
Taicong Tan ◽  
Suhao Niu ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Carbon Metabolism ◽  
Central Carbon Metabolism ◽  
Central Carbon

scholarly journals IntracellularStaphylococcus aureusModulates Host Central Carbon Metabolism To Activate Autophagy

mSphere ◽  
2018 ◽  
Vol 3 (4) ◽  
pp. e00374-18 ◽  
Author(s):  
Natalia Bravo-Santano ◽  
James K. Ellis ◽  
Luis M. Mateos ◽  
Yolanda Calle ◽  
Hector C. Keun ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Host Cell ◽  
Carbon Metabolism ◽  
Central Carbon Metabolism ◽  
Metabolic Changes ◽  
Autophagic Flux ◽  
Content Type ◽  
Central Carbon ◽  
Infected Cells ◽  
Intracellular Proliferation

ABSTRACTStaphylococcus aureusis a facultative intracellular pathogen that invades and replicates within many types of phagocytic and nonphagocytic cells. During intracellular infection,S. aureusis capable of subverting xenophagy and escaping to the cytosol of the host cell. Furthermore, drug-induced autophagy facilitates the intracellular replication ofS. aureus, but the reasons behind this are unclear. Here, we have studied the host central carbon metabolism duringS. aureusintracellular infection. We found extensive metabolic rerouting and detected several distinct metabolic changes that suggested starvation-induced autophagic flux in infected cells. These changes included increased uptake but lower intracellular levels of glucose and low abundance of several essential amino acids, as well as markedly upregulated glutaminolysis. Furthermore, we show that AMP-activated protein kinase (AMPK) and extracellular signal-regulated kinase (ERK) phosphorylation levels are significantly increased in infected cells. Interestingly, while autophagy was activated in response toS. aureusinvasion, most of the autophagosomes detected in infected cells did not contain bacteria, suggesting thatS. aureusinduces the autophagic flux during cell invasion for energy generation and nutrient scavenging. Accordingly, AMPK inhibition haltedS. aureusintracellular proliferation.IMPORTANCEStaphylococcus aureusescapes from immune recognition by invading a wide range of human cells. Once the pathogen becomes intracellular, the most important last resort antibiotics are not effective. Therefore, novel anti-infective therapies against intracellularS. aureusare urgently needed. Here, we have studied the physiological changes induced in the host cells byS. aureusduring its intracellular proliferation. This is important, because the pathogen exploits the host cell’s metabolism for its own proliferation. We find thatS. aureusseverely depletes glucose and amino acid pools, which leads to increased breakdown of glutamine by the host cell in an attempt to meet its own metabolic needs. All of these metabolic changes activate autophagy in the host cell for nutrient scavenging and energy generation. The metabolic activation of autophagy could be used by the pathogen to sustain its own intracellular survival, making it an attractive target for novel anti-infectives.

scholarly journals Network Identification and Flux Quantification in the Central Metabolism of Saccharomyces cerevisiae under Different Conditions of Glucose Repression

2001 ◽  
Vol 183 (4) ◽  
pp. 1441-1451 ◽  
Author(s):  
Andreas Karoly Gombert ◽  
Margarida Moreira dos Santos ◽  
Bjarke Christensen ◽  
Jens Nielsen
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Growth Rate ◽  
Specific Growth Rate ◽  
Batch Culture ◽  
Network Structure ◽  
Carbon Metabolism ◽  
Specific Growth ◽  
Central Carbon Metabolism ◽  
Published Data ◽  
Central Carbon

ABSTRACT The network structure and the metabolic fluxes in central carbon metabolism were characterized in aerobically grown cells ofSaccharomyces cerevisiae. The cells were grown under both high and low glucose concentrations, i.e., either in a chemostat at steady state with a specific growth rate of 0.1 h−1 or in a batch culture with a specific growth rate of 0.37 h−1. Experiments were carried out using [1-13C]glucose as the limiting substrate, and the resulting summed fractional labelings of intracellular metabolites were measured by gas chromatography coupled to mass spectrometry. The data were used as inputs to a flux estimation routine that involved appropriate mathematical modelling of the central carbon metabolism ofS. cerevisiae. The results showed that the analysis is very robust, and it was possible to quantify the fluxes in the central carbon metabolism under both growth conditions. In the batch culture, 16.2 of every 100 molecules of glucose consumed by the cells entered the pentose-phosphate pathway, whereas the same relative flux was 44.2 per 100 molecules in the chemostat. The tricarboxylic acid cycle does not operate as a cycle in batch-growing cells, in contrast to the chemostat condition. Quantitative evidence was also found for threonine aldolase and malic enzyme activities, in accordance with published data. Disruption of the MIG1 gene did not cause changes in the metabolic network structure or in the flux pattern.

scholarly journals Metabolic Profiling from an Asymptomatic Ferret Model of SARS-CoV-2 Infection

2021 ◽  
Author(s):  
David J. Beale ◽  
Rohan Shah ◽  
Avinash V. Karpe ◽  
Katie E. Hillyer ◽  
Alexander J. McAuley ◽  
...  
Keyword(s):  
Carbon Metabolism ◽  
Impact Analysis ◽  
Metabolic Response ◽  
Central Carbon Metabolism ◽  
Pentose Phosphate ◽  
Nasal Wash ◽  
Viral Shedding ◽  
Central Carbon ◽  
Pentose Phosphate Pathways ◽  
The Impact

COVID-19 is a contagious respiratory disease that is causing significant global morbidity and mortality. Understanding the impact of a SARS-CoV-2 infection on the host metabolism is still in its infancy but of great importance. Herein, we investigated the metabolic response during viral shedding and post-shedding in an asymptomatic SARS-CoV-2 ferret model (n=6) challenged with two SARS-CoV-2 isolates. Virological and metabolic analyses were performed on (minimally invasive) collected oral swabs, rectal swabs, and nasal washes. Fragments of SARS-CoV-2 RNA were only found in the nasal wash samples in four of the six ferrets, and in the samples collected 3 to 9 days post-infection (referred to as viral shedding). Central carbon metabolism metabolites were analyzed during viral shedding and post-shedding periods using a dynamic MRM (dMRM) database and method. Subsequent untargeted metabolomics and lipidomics of the same samples were performed using an LC-QToF-MS methodology, building upon the identified differentiated central carbon metabolism metabolites. Multivariate analysis of the acquired data identified 29 significant metabolites and three lipids that were subjected to pathway enrichment and impact analysis. The presence of viral shedding coincided with the challenge dose administered and significant changes in the citric acid cycle, purine metabolism, and pentose phosphate pathways, amongst others, in the host nasal wash samples. An elevated immune response in the host was also observed between the two isolates studied. These results support other reported metabolomic-based findings found in clinical observational studies and indicate the utility of metabolomics applied to ferrets for further COVID-19 research that advances early diagnosis of asymptomatic and mild clinical COVID-19 infections, in addition to assessing the effectiveness of new or re-purposed drug therapies.

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