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  1. Article: Complex glutamate labeling from [U-13C]glucose or [U-13C]lactate in co-cultures of cerebellar neurons and astrocytes.

    Bak, Lasse K / Waagepetersen, Helle S / Melø, Torun M / Schousboe, Arne / Sonnewald, Ursula

    Neurochemical research

    2007  Volume 32, Issue 4-5, Page(s) 671–680

    Abstract: ... glutamatergic) and astrocytes. One set of cultures was superfused (90 min) in the presence of either [U-(13)C ... glucose (2.5 mM) and lactate (1 mM) or [U-(13)C]lactate (1 mM) and glucose (2.5 mM). Other sets ... of cultures were incubated in medium containing [U-(13)C]lactate (1 mM) and glucose (2.5 mM) for 4 h ...

    Abstract Glutamate metabolism was studied in co-cultures of mouse cerebellar neurons (predominantly glutamatergic) and astrocytes. One set of cultures was superfused (90 min) in the presence of either [U-(13)C]glucose (2.5 mM) and lactate (1 mM) or [U-(13)C]lactate (1 mM) and glucose (2.5 mM). Other sets of cultures were incubated in medium containing [U-(13)C]lactate (1 mM) and glucose (2.5 mM) for 4 h. Regardless of the experimental conditions cell extracts were analyzed using mass spectrometry and nuclear magnetic resonance spectroscopy. (13)C labeling of glutamate was much higher than that of glutamine under all experimental conditions indicating that acetyl-CoA from both lactate and glucose was preferentially metabolized in the neurons. Aspartate labeling was similar to that of glutamate, especially when [U-(13)C]glucose was the substrate. Labeling of glutamate, aspartate and glutamine was lower in the cells incubated with [U-(13)C]lactate. The first part of the pyruvate recycling pathway, pyruvate formation, was detected in singlet and doublet labeling of alanine under all experimental conditions. However, full recycling, detectable in singlet labeling of glutamate in the C-4 position was only quantifiable in the superfused cells both from [U-(13)C]glucose and [U-(13)C]lactate. Lactate and alanine were mostly uniformly labeled and labeling of alanine was the same regardless of the labeled substrate present and higher than that of lactate when superfused in the presence of [U-(13)C]glucose. These results show that metabolism of pyruvate, the precursor for lactate, alanine and acetyl-CoA is highly compartmentalized.
    MeSH term(s) Alanine/metabolism ; Astrocytes/cytology ; Astrocytes/metabolism ; Cerebellum/cytology ; Cerebellum/metabolism ; Chromatography, High Pressure Liquid ; Coculture Techniques ; Gas Chromatography-Mass Spectrometry ; Glucose/metabolism ; Glutamic Acid/metabolism ; Lactic Acid/metabolism ; Magnetic Resonance Spectroscopy ; Mass Spectrometry ; Neurons/metabolism ; Perfusion ; Pyruvic Acid/metabolism ; gamma-Aminobutyric Acid/metabolism
    Chemical Substances Lactic Acid (33X04XA5AT) ; Glutamic Acid (3KX376GY7L) ; gamma-Aminobutyric Acid (56-12-2) ; Pyruvic Acid (8558G7RUTR) ; Glucose (IY9XDZ35W2) ; Alanine (OF5P57N2ZX)
    Language English
    Publishing date 2007-04
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 199335-5
    ISSN 1573-6903 ; 0364-3190
    ISSN (online) 1573-6903
    ISSN 0364-3190
    DOI 10.1007/s11064-006-9161-4
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  2. Article ; Online: Brain [U-13 C]glucose metabolism in mice with decreased α-ketoglutarate dehydrogenase complex activity.

    Nilsen, Linn Hege / Shi, Qingli / Gibson, Gary E / Sonnewald, Ursula

    Journal of neuroscience research

    2011  Volume 89, Issue 12, Page(s) 1997–2007

    Abstract: ... DLST knockout mice (DLST+/-) and corresponding wild-type mice injected with [U-(13) C]glucose and ...

    Abstract The activity of the α-ketoglutarate dehydrogenase complex (KGDHC), a mitochondrial enzyme complex that mediates the oxidative decarboxylation of α-ketoglutarate in the TCA cycle, is reduced in Alzheimer's disease. We investigated the metabolic effects of a partial KGDHC activity reduction on brain glucose metabolism using mice with disrupted expression of dihydrolipoyl succinyltransferase (DLST; gene encoding the E2k subunit of KGDHC). Brain tissue extracts from cortex and cerebellum of 6-week-old heterozygote DLST knockout mice (DLST+/-) and corresponding wild-type mice injected with [U-(13) C]glucose and decapitated 15 min later were analyzed. An increase in the concentration of glucose in cortex suggested a decrease in the cortical utilization of glucose in DLST+/- mice. Furthermore, the concentration and (13) C labelling of aspartate in cortex were reduced in DLST+/- mice. This decline was likely caused by a decrease in the pool of oxaloacetate. In contrast to results from cell culture studies, no indications of altered glycolysis or GABA shunt activity were found. Glucose metabolism in the cerebellum was unaffected by the decrease in KGDHC activity. Among metabolites not related to glucose metabolism, the concentration of taurine was decreased in the cortex, and that of tyrosine was increased in the cerebellum. These results imply that diminished KGDHC activity has the potential to induce the reduction in glucose utilization that is seen in several neurodegenerative diseases.
    MeSH term(s) Animals ; Brain/metabolism ; Carbon Radioisotopes ; Chromatography, Gas ; Chromatography, High Pressure Liquid ; Glucose/metabolism ; Ketoglutarate Dehydrogenase Complex/metabolism ; Magnetic Resonance Spectroscopy ; Mass Spectrometry ; Mice ; Mice, Inbred C57BL ; Mice, Knockout ; Neurodegenerative Diseases/metabolism
    Chemical Substances Carbon Radioisotopes ; Ketoglutarate Dehydrogenase Complex (EC 1.2.4.2) ; Glucose (IY9XDZ35W2)
    Language English
    Publishing date 2011-03-03
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't
    ZDB-ID 195324-2
    ISSN 1097-4547 ; 0360-4012
    ISSN (online) 1097-4547
    ISSN 0360-4012
    DOI 10.1002/jnr.22606
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  3. Article ; Online: Unlocking dynamic root phenotypes for simultaneous enhancement of water and phosphorus uptake.

    Nasr Esfahani, Maryam / Sonnewald, Uwe

    Plant physiology and biochemistry : PPB

    2024  Volume 207, Page(s) 108386

    Abstract: Phosphorus (P) and water are crucial for plant growth, but their availability is challenged by climate change, leading to reduced crop production and global food security. In many agricultural soils, crop productivity is confronted by both water and P ... ...

    Abstract Phosphorus (P) and water are crucial for plant growth, but their availability is challenged by climate change, leading to reduced crop production and global food security. In many agricultural soils, crop productivity is confronted by both water and P limitations. The diminished soil moisture decreases available P due to reduced P diffusion, and inadequate P availability diminishes tissue water status through modifications in stomatal conductance and a decrease in root hydraulic conductance. P and water display contrasting distributions in the soil, with P being concentrated in the topsoil and water in the subsoil. Plants adapt to water- and P-limited environments by efficiently exploring localized resource hotspots of P and water through the adaptation of their root system. Thus, developing cultivars with improved root architecture is crucial for accessing and utilizing P and water from arid and P-deficient soils. To meet this goal, breeding towards multiple advantageous root traits can lead to better cultivars for water- and P-limited environments. This review discusses the interplay of P and water availability and highlights specific root traits that enhance the exploration and exploitation of optimal resource-rich soil strata while reducing metabolic costs. We propose root ideotype models, including 'topsoil foraging', 'subsoil foraging', and 'topsoil/subsoil foraging' for maize (monocot) and common bean (dicot). These models integrate beneficial root traits and guide the development of water- and P-efficient cultivars for challenging environments.
    MeSH term(s) Phosphorus/metabolism ; Water/metabolism ; Plant Roots/metabolism ; Plant Breeding ; Phenotype ; Soil
    Chemical Substances Phosphorus (27YLU75U4W) ; Water (059QF0KO0R) ; Soil
    Language English
    Publishing date 2024-01-24
    Publishing country France
    Document type Journal Article ; Review
    ZDB-ID 742978-2
    ISSN 1873-2690 ; 0981-9428
    ISSN (online) 1873-2690
    ISSN 0981-9428
    DOI 10.1016/j.plaphy.2024.108386
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  4. Article ; Online: Yield reduction caused by elevated temperatures and high nitrogen fertilization is mitigated by SP6A overexpression in potato (Solanum tuberosum L.).

    Koch, Lisa / Lehretz, Günter G / Sonnewald, Uwe / Sonnewald, Sophia

    The Plant journal : for cell and molecular biology

    2024  Volume 117, Issue 6, Page(s) 1702–1715

    Abstract: Potatoes (Solanum tuberosum L.) are a fundamental staple for millions of people worldwide. They provide essential amino acids, vitamins, and starch - a vital component of the human diet, providing energy and serving as a source of fiber. Unfortunately, ... ...

    Abstract Potatoes (Solanum tuberosum L.) are a fundamental staple for millions of people worldwide. They provide essential amino acids, vitamins, and starch - a vital component of the human diet, providing energy and serving as a source of fiber. Unfortunately, global warming is posing a severe threat to this crop, leading to significant yield losses, and thereby endangering global food security. Industrial agriculture traditionally relies on excessive nitrogen (N) fertilization to boost yields. However, it remains uncertain whether this is effective in combating heat-related yield losses of potato. Therefore, our study aimed to investigate the combinatory effects of heat stress and N fertilization on potato tuber formation. We demonstrate that N levels and heat significantly impact tuber development. The combination of high N and heat delays tuberization, while N deficiency initiates early tuberization, likely through starvation-induced signals, independent of SELF-PRUNING 6A (SP6A), a critical regulator of tuberization. We also found that high N levels in combination with heat reduce tuber yield rather than improve it. However, our study revealed that SP6A overexpression can promote tuberization under these inhibiting conditions. By utilizing the excess of N for accumulating tuber biomass, SP6A overexpressing plants exhibit a shift in biomass distribution towards the tubers. This results in an increased yield compared to wild-type plants. Our results highlight the role of SP6A overexpression as a viable strategy for ensuring stable potato yields in the face of global warming. As such, our findings provide insights into the complex factors impacting potato crop productivity.
    MeSH term(s) Humans ; Solanum tuberosum ; Temperature ; Nitrogen/metabolism ; Fertilization ; Plant Tubers ; Plant Proteins/genetics ; Plant Proteins/metabolism
    Chemical Substances Nitrogen (N762921K75) ; Plant Proteins
    Language English
    Publishing date 2024-02-09
    Publishing country England
    Document type Journal Article
    ZDB-ID 1088037-9
    ISSN 1365-313X ; 0960-7412
    ISSN (online) 1365-313X
    ISSN 0960-7412
    DOI 10.1111/tpj.16679
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  5. Article: GABA alters the metabolic fate of [U-13C]glutamate in cultured cortical astrocytes.

    McKenna, Mary C / Sonnewald, Ursula

    Journal of neuroscience research

    2005  Volume 79, Issue 1-2, Page(s) 81–87

    Abstract: ... magnetic resonance (NMR) spectroscopy. Cerebral cortical astrocytes were incubated with 0.5 mM [U-(13)C ... from the tricarboxylic acid (TCA) cycle were present in the cells. The consumption of [U-(13)C]glutamate and glucose was ... unchanged in the presence of GABA; however, the formation of [U-(13)C]lactate and [U-(13)C]aspartate ...

    Abstract The effect of gamma-aminobutyric acid (GABA) on glutamate metabolism was studied by (13)C-nuclear magnetic resonance (NMR) spectroscopy. Cerebral cortical astrocytes were incubated with 0.5 mM [U-(13)C]glutamate and 5 mM glucose in the presence or absence of 0.2 mM GABA for 2 hr. (13)C-labeled glutamate, glutamine, and aspartate were observed in cell extracts, and (13)C-labeled glutamine and lactate were present in the media. Both uniformly labeled glutamate and [1,2,3-(13)C]glutamate derived from the tricarboxylic acid (TCA) cycle were present in the cells. The consumption of [U-(13)C]glutamate and glucose was unchanged in the presence of GABA; however, the formation of [U-(13)C]lactate and [U-(13)C]aspartate from metabolism of [U-(13)C]glutamate was increased in cells incubated with GABA. The total concentration of aspartate was increased to the same extent as the (13)C-labeled aspartate, suggesting increased entry of [U-(13)C]glutamate into the TCA cycle to allow for the transamination of GABA. Although the concentrations of unlabeled glucose and lactate in the media were unchanged in the presence of GABA, the concentration of alanine was decreased, indicating that there was decreased transamination of the unlabeled pyruvate from glucose metabolism. The amount of [U-(13)C]glutamate converted to [U-(13)C]glutamine and [U-(13)C]lactate was increased in the presence of GABA. However, since the overall consumption of [U-(13)C]glutamate was not different, it can be concluded that the amount of [U-(13)C]glutamate used for energy was decreased. This suggests that exogenous GABA could substitute for glutamate as an energy source for astrocytes. The results indicate that the presence of GABA influences the metabolic fate of both glutamate and glucose in astrocytes, suggesting that fluctuations in the concentration of GABA in normal and pathological conditions can alter the compartmentation of glial metabolism in brain.
    MeSH term(s) Amino Acids/metabolism ; Animals ; Animals, Newborn ; Aspartic Acid/metabolism ; Astrocytes/drug effects ; Astrocytes/metabolism ; Carbon Isotopes/metabolism ; Cerebral Cortex/cytology ; Extracellular Space/drug effects ; Extracellular Space/metabolism ; Glutamic Acid/metabolism ; Lactic Acid/metabolism ; Magnetic Resonance Spectroscopy/methods ; Models, Biological ; Rats ; gamma-Aminobutyric Acid/pharmacology
    Chemical Substances Amino Acids ; Carbon Isotopes ; Aspartic Acid (30KYC7MIAI) ; Lactic Acid (33X04XA5AT) ; Glutamic Acid (3KX376GY7L) ; gamma-Aminobutyric Acid (56-12-2)
    Language English
    Publishing date 2005-01
    Publishing country United States
    Document type Comparative Study ; Journal Article ; Research Support, Non-U.S. Gov't ; Research Support, U.S. Gov't, P.H.S.
    ZDB-ID 195324-2
    ISSN 1097-4547 ; 0360-4012
    ISSN (online) 1097-4547
    ISSN 0360-4012
    DOI 10.1002/jnr.20309
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  6. Article: Jens Kossmann 1963-2023 - a scientist with a passion for plant biology and people.

    Lloyd, James R / Sonnewald, Uwe

    Frontiers in plant science

    2023  Volume 14, Page(s) 1266078

    Language English
    Publishing date 2023-08-23
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2613694-6
    ISSN 1664-462X
    ISSN 1664-462X
    DOI 10.3389/fpls.2023.1266078
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  7. Article ; Online: Metabolism and development.

    Fernie, Alisdair R / Sonnewald, Uwe / Sampathkumar, Arun

    Journal of plant physiology

    2024  Volume 295, Page(s) 154208

    Language English
    Publishing date 2024-02-28
    Publishing country Germany
    Document type Editorial
    ZDB-ID 283647-6
    ISSN 1618-1328 ; 0176-1617
    ISSN (online) 1618-1328
    ISSN 0176-1617
    DOI 10.1016/j.jplph.2024.154208
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  8. Article: Effect of the pyrrolopyrimidine lipid peroxidation inhibitor U-101033E on neuronal and astrocytic metabolism and infarct volume in rats with transient middle cerebral artery occlusion.

    Håberg, A / Qu, H / Hjelstuen, M H / Sonnewald, U

    Neurochemistry international

    2007  Volume 50, Issue 7-8, Page(s) 932–940

    Abstract: ... of the pyrrolopyrimidine lipid peroxidation inhibitor, U-101033E, on infarct volume and neuronal and astrocytic metabolism ... followed by 140 min of reperfusion and randomly assigned to control (n=17) or U-101033E treatment (n=16 ... representing penumbra and ischemic core were analyzed with 13C NMRS and HPLC. U-101033E did not affect ...

    Abstract The aim of the present study was to assess the effect of post ictal administration of the pyrrolopyrimidine lipid peroxidation inhibitor, U-101033E, on infarct volume and neuronal and astrocytic metabolism in rats with transient middle cerebral artery occlusion (MCAO). Rats were subjected to 120 min of MCAO followed by 140 min of reperfusion and randomly assigned to control (n=17) or U-101033E treatment (n=16). Drug infusion started 5 min after MCAO and lasted 220 min with a 15 min interruption during the reperfusion procedure. Sixteen rats underwent diffusion weighted imaging 260 min after ictus, from which the apparent diffusion coefficient (ADC) was determined. Seventeen rats received an iv bolus injection of [1-13C]glucose and [1,2-13C]acetate 245 min after ictus. Tissue extracts from two brain regions representing penumbra and ischemic core were analyzed with 13C NMRS and HPLC. U-101033E did not affect the volume of ischemic tissue estimated from the ADC maps. In the penumbra, U-101033E specifically decreased mitochondrial pyruvate metabolism via both pyruvate dehydrogenase and pyruvate carboxylase pathways. Thus, U-101033E impaired both neuronal and astrocytic mitochondrial pyruvate metabolism. At the same time anaerobic glucose usage was increased, leading to increased lactate labeling and content. Also alanine labeling was increased. The data do not support lactate as an important substrate for neuronal mitochondria in ischemia-reperfusion. A similar pattern of reduced mitochondrial pyruvate metabolism and increased cytosolic pyruvate metabolism was found in the irreversibly damaged ischemic core. The present study highlights the importance of other outcome measures than ischemic tissue volume for evaluation of drug efficacy in animal models, which in turn could increase the likelihood of success in clinical trials.
    MeSH term(s) Acetates/metabolism ; Animals ; Astrocytes/metabolism ; Cerebral Infarction/metabolism ; Cerebral Infarction/pathology ; Cerebral Infarction/prevention & control ; Disease Models, Animal ; Glucose/metabolism ; Glycolysis/drug effects ; Lipid Peroxidation/drug effects ; Magnetic Resonance Imaging ; Male ; Middle Cerebral Artery/drug effects ; Middle Cerebral Artery/pathology ; Nerve Tissue Proteins/metabolism ; Neurons/drug effects ; Neurons/metabolism ; Pyrimidines/metabolism ; Pyrimidines/pharmacology ; Pyrroles/metabolism ; Pyrrolidines/pharmacology ; Rats ; Rats, Wistar
    Chemical Substances Acetates ; Nerve Tissue Proteins ; Pyrimidines ; Pyrroles ; Pyrrolidines ; U 101033E ; Glucose (IY9XDZ35W2)
    Language English
    Publishing date 2007-06
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 283190-9
    ISSN 1872-9754 ; 0197-0186
    ISSN (online) 1872-9754
    ISSN 0197-0186
    DOI 10.1016/j.neuint.2006.12.005
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  9. Article ; Online: Plant synthetic biology: One answer to global challenges.

    Sonnewald, Uwe

    Journal of integrative plant biology

    2018  Volume 60, Issue 12, Page(s) 1124–1126

    MeSH term(s) Genetic Engineering ; Genome, Plant ; Internationality ; Plant Breeding ; Plants/genetics ; Synthetic Biology
    Language English
    Publishing date 2018-11-22
    Publishing country China (Republic : 1949- )
    Document type Editorial ; Introductory Journal Article
    ZDB-ID 2130095-1
    ISSN 1744-7909 ; 1672-9072
    ISSN (online) 1744-7909
    ISSN 1672-9072
    DOI 10.1111/jipb.12750
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  10. Article: Evaluation of the importance of transamination versus deamination in astrocytic metabolism of [U-13C]glutamate.

    Westergaard, N / Drejer, J / Schousboe, A / Sonnewald, U

    Glia

    1996  Volume 17, Issue 2, Page(s) 160–168

    Abstract: ... the significance of transamination for the oxidative metabolism of glutamate. Cultures were incubated with [U-13C ... and aspartate could only arise via metabolism of [U-13C]glutamate through the tricarboxylic acid (TCA ...

    Abstract Glutamate metabolism was studied in primary cultures of cerebral cortical astrocytes to determine the significance of transamination for the oxidative metabolism of glutamate. Cultures were incubated with [U-13C]glutamate (0.5 mM) in the presence and absence of the transaminase inhibitor aminooxyacetic acid (AOAA) and in some cases with methionine sulfoximine, an inhibitor of glutamine synthetase. Perchloric acid extracts of the cells as well as redissolved lyophilized incubation media were subjected to nuclear magnetic resonance spectroscopy to identify 13C-labeled metabolites. Additionally, biochemical analyses were performed to quantify amino acids, lactate, citrate, and ammonia. Glutamine released into the medium and intracellular glutamate were labeled uniformly to a large extent, but the C-3 position showed not only the expected apparent triplet but also a doublet due to 12C incorporation into the C-4 and C-5 positions. Incorporation of 12C into the C-4 and C-5 positions of glutamate and glutamine as well as labeling of lactate, citrate, malate, and aspartate could only arise via metabolism of [U-13C]glutamate through the tricarboxylic acid (TCA) cycle. Entry of the carbon skeleton of glutamate into the TCA cycle must proceed via 2-oxoglutarate. This conversion can occur as a transamination or an oxidative deamination. After blocking transamination with AOAA, metabolism of glutamate through the TCA cycle was still taking place since lactate labeling was only slightly reduced. Glutamate and glutamine synthesis from 2-oxoglutarate could, however, not be detected under this condition. It therefore appears that while glutamate dehydrogenase is important for glutamate degradation, glutamate biosynthesis occurs mainly as a transamination.
    MeSH term(s) Amino Acids/metabolism ; Animals ; Astrocytes/metabolism ; Cerebral Cortex/metabolism ; Deamination ; Glutamic Acid/metabolism ; Mice ; Mice, Inbred Strains
    Chemical Substances Amino Acids ; Glutamic Acid (3KX376GY7L)
    Language English
    Publishing date 1996-06
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 639414-0
    ISSN 1098-1136 ; 0894-1491
    ISSN (online) 1098-1136
    ISSN 0894-1491
    DOI 10.1002/(SICI)1098-1136(199606)17:2<160::AID-GLIA7>3.0.CO;2-6
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