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See detailMetabolic enzymes from psychrophilic bacteria: Challenge of adaptation to low temperatures in ornithine carbamoyltransferase from Moritella abyssi
Xu, Y.; Feller, Georges ULg; Gerday, Charles ULg et al

in Journal of Bacteriology (2003), 185(7), 2161-2168

The enzyme ornithine carbamoyltransferase (OTCase) of Motitella abyssi (OTCase(Mab)), a new, strictly psychrophilic and piezophilic bacterial species, was purified. OTCase(Mab) displays maximal activity ... [more ▼]

The enzyme ornithine carbamoyltransferase (OTCase) of Motitella abyssi (OTCase(Mab)), a new, strictly psychrophilic and piezophilic bacterial species, was purified. OTCase(Mab) displays maximal activity at rather low temperatures (23 to 25degreesC) compared to other cold-active enzymes and is much less thermoresistant than its homologues from Escherichia coli or thermophilic procaryotes. In vitro the enzyme is in equilibrium between a trimeric state and a dodecameric, more stable state. The melting point and denaturation enthalpy changes for the two forms are considerably lower than the corresponding values for the dodecameric Pyrococcus furiosus OTCase and for a thermolabile trimeric mutant thereof. OTCase(Mab) displays higher K-m values for ornithine and carbamoyl phosphate than mesophilic and thermophilic OTCases and is only weakly inhibited by the bisubstrate analogue delta-N-phosphonoacetyl-L-ornithine (PALO). OTCase(Mab) differs from other, nonpsychrophilic OTCases by substitutions in the most conserved motifs, which probably contribute to the comparatively high K-m values and the lower sensitivity to PALO. The K. for ornithine, however, is substantially lower at low temperatures. A survey of the catalytic efficiencies (k(cat)/K-m) of OTCases adapted to different temperatures showed that OTCase(Mab) activity remains suboptimal at low temperature despite the 4.5-fold decrease in the K-m value for ornithine observed when the temperature is brought from 20 to 5degreesC. OTCase(Mab) adaptation to cold indicates a trade-off between affinity and catalytic velocity, suggesting that optimization of key metabolic enzymes at low temperatures may be constrained by natural limits. [less ▲]

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See detailMetabolic monitoring of chemosensitivity with 18FDG PET.
Jerusalem, Guy ULg; Belhocine, Tarik Z

in Methods in Molecular Medicine (2005), 111

Accurate and early evaluation of tumor response to chemotherapy is a growing clinical need for optimal management of oncology patients. This is even more warranted by the lack of appropriate response ... [more ▼]

Accurate and early evaluation of tumor response to chemotherapy is a growing clinical need for optimal management of oncology patients. This is even more warranted by the lack of appropriate response evaluation criteria to new molecularly targeted anticancer therapies. In the two last decades, new developments in the field of nuclear oncology have allowed the introduction of various radiopharmaceuticals to be used on dedicated imaging devices. In the present chapter, we report the added value that positron emission tomography (PET) with 18F-fluorodeoxyglucose (18FDG) may offer to assess tumor response to treatment. PET is a high-end imaging technology using 18FDG as metabolic tracer that mimics the biochemical behavior of the natural glucose molecule. Because most tumor types exhibit increased glucose metabolism, the imaging of 18FDG uptake within cancer tissues prior to any treatment enables the metabolic technique to follow tumor responsiveness sequentially after one or several courses of chemotherapy. Moreover, metabolic tumor response evaluated by 18FDG PET often precedes morphological tumor changes measured by computed tomography or magnetic resonance imaging. So far, the suboptimal proper ties of 18FDG tracer and the lack of standardized methodology in PET imaging remain objective limitations for qualitative and quantitative assessment of chemosensitivity using the metabolic method. [less ▲]

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See detailMetabolic Pathway Analysis and Reduction for Mammalian Cell Cultures-Towards Macroscopic Modeling
Niu, H; Amribt, Z; Fickers, Patrick ULg et al

in Chemical Engineering Science (2013), (102), 461-473

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See detailMetabolic plasticity of wild-type and AOX-deficient Chlamydomonas reinhardtii cells related to the inorganic nitrogen source (nitrate or ammonium), as revealed by a 2D-DIGE comparative proteomic analysis
Gerin, Stéphanie ULg; Mathy, Grégory; Franck, Fabrice ULg

Poster (2012, June 15)

In the model unicellular green alga Chlamydomonas reinhardtii, both nitrate and ammonium can be used as primary inorganic nitrogen sources. Interestingly, the expression of the mitochondrial alternative ... [more ▼]

In the model unicellular green alga Chlamydomonas reinhardtii, both nitrate and ammonium can be used as primary inorganic nitrogen sources. Interestingly, the expression of the mitochondrial alternative oxidase (AOX), an "energy-dissipating" ubiquinol-oxygen oxidoreductase of the mitochondrial electron transport chain, is under the control of the exogenous nitrogen source : it is activated in nitrate-grown cells and repressed in ammonium-grown cells at both transcriptional and translational levels. This regulation of AOX by nitrogen is Chlamydomonas-specific and currently its bioenergetic and metabolic significance is poorly understood. In order to get clues to this peculiar phenomenon, we characterized the global metabolic response of a wild-type strain (WT) and an AOX-deficient mutant (AOX-) obtained by RNA interference grown either on nitrate or ammonium. For this purpose, we used a highly accurate 2D electrophoresis-based comparative proteomic approach (2D-DIGE) to compare the cellular proteomes of nitrate and ammonium-grown WT and AOX- Chlamydomonas. The analysis was performed in the middle of the exponential growth phase in mixotrophic conditions. It revealed many proteomic modifications between WT and AOX- cells and a smaller number between nitrate and ammonium-grown cells. In nitrate-grown cells, we notably observed an important up-regulation of glutamine synthetase. Interestingly, in AOX- cells, we respectively detected a general down-regulation and a general up-regulation of mitochondrial and chloroplastic bioenergetic enzymes, and also an important up-regulation of glutathione-dependent oxidative stress defense systems together with a remarkable down-regulation of methionine synthase. Altogether these results and previous studies provide new features in understanding the metabolic adaptations occurring in response to the inorganic nitrogen source with emphasis on the role played by AOX. [less ▲]

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See detailMetabolic profile of mixed culture acidogenic fermentation of lignocellulosic residues and the effect of upstream substrate fractionation by steam explosion
Perimenis, Anastasios; van Aarle, Ingrid; Nicolay, Thomas et al

in Biomass Conversion and Biorefinery (in press)

Lignocellulosic biomass residues have attracted attention for the sustainable production of molecules for material and energetic use through biochemical conversion. Their recalcitrant structure prevents a ... [more ▼]

Lignocellulosic biomass residues have attracted attention for the sustainable production of molecules for material and energetic use through biochemical conversion. Their recalcitrant structure prevents a broader use and asks for the development of sustainable techniques that can efficiently separate, recover and valorize the constituting components. In a cascading concept, residual streams of such processes can be further exploited in an attempt to valorize the largest possible fraction of the initial material. Three lignocellulosic substrates, namely dried sugar beet pulp, wheat bran and miscanthus straw, were upstream fractionated by steam explosion to extract the hemicellulose fraction. This study evaluated the valorization of the residual solid fraction through mixed acidogenic fermentation for the production of volatile fatty acids (VFA) as platform chemicals. Batch experiments have been conducted for the reference material (non-treated) and the solid fraction remaining after steam explosion, with and without the addition of an external mixed inoculum. Steam explosion residues contained less hemicellulose than the initial materials. The difference in the fermentation profile between steam explosion residues and non-treated substrates is dependent on the substrate. Maximum total VFA (tVFA) concentration was 18.8 gCOD/kgmixed_liquor, and maximum yield of chemical oxygen demand (COD) conversion into tVFAwas 33 % for the case of non-treated inoculated beet pulp. [less ▲]

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See detailMetabolic profiling in pea seeds
Vigeolas, Hélène ULg

Conference (2005)

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See detailMetabolic properties of bovine muscles: regulation by genetic and nutritional factors.
Hocquette, J. F.; Cabaraux, Jean-François ULg; Jurie, C. et al

in Book of absracts of the 54th Annual Meeting of the European Association for Animal Production (2003)

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See detailMetabolic reprogramming in transformed mouse cortical astrocytes: a proteomic study.
Bentaib, Azeddine; De Tullio, Pascal ULg; Chneiweiss, Herve et al

in Journal of proteomics (2015), 113

Metabolic reprogramming is thought to play a key role in sustaining the survival and proliferation of cancer cells. These changes facilitate for example the uptake and release of nutrients required for ... [more ▼]

Metabolic reprogramming is thought to play a key role in sustaining the survival and proliferation of cancer cells. These changes facilitate for example the uptake and release of nutrients required for nucleotide, protein and lipid synthesis necessary for macromolecule assembly and tumor growth. We applied a 2D-DIGE (Two-Dimensional Differential in-Gel Electrophoresis) quantitative proteomic analysis to characterize the proteomes of mouse astrocytes that underwent in vitro cancerous transformation, and of their normal counterparts. Metabolic reprogramming effects on enzymatic and structural protein expression as well as associated metabolites abundance were quantified. Using enzymatic activity measurements and zymography, we documented and confirmed several changes in abundance and activity of various isoenzymes likely to participate in metabolic reprogramming. We found that after transformation, the cells increase their expression of glycolytic enzymes, thus augmenting their ability to use aerobic glycolysis (Warburg effect). An increased capacity to dispose of reducing equivalents through lactate production was also documented. Major effects on carbohydrates, amino acids and nucleotides metabolic enzymes were also observed. Conversely, the transformed cells reduced their enzymatic capacity for reactions of tricarboxylic acid oxidation, for neurotransmitter (glutamate) metabolism, for oxidative stress defense and their expression of astroglial markers. BIOLOGICAL SIGNIFICANCE: The use of a global approach based on a 2D DIGE analysis allows obtaining a comprehensive view of the metabolic reprogramming undergone by astrocytes upon cancerous transformation. Indeed, except for a few enzymes such as pyruvate carboxylase and glutaminase that were not detected in our initial analysis, pertinent information on the abundance of most enzymes belonging to pathways relevant to metabolic reprogramming was directly obtained. In this in vitro model, transformation causes major losses of astrocyte-specific proteins and functions and the acquisition of metabolic adaptations that favor intermediate metabolites production for increased macromolecule biosynthesis. Thus our approach appears to be readily applicable for the investigation of changes in protein abundance that determine various transformed cell phenotypes. It could similarly be applied to the evaluation of the effects of treatments aimed at correcting the consequences of cell transformation. [less ▲]

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See detailMetabolic responses to exercise and training
Votion, Dominique ULg

in Hinchcliff K.W; Kaneps A.J.; Geor R.J. (Eds.) Equine Sport Medicine and Surgery (2014)

This chapter reviews the whole-body and muscular metabolic responses and also describes the effects of training adaptation on these processes.

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See detailMetabolic stress as a paradigm to elucidate genotype-environment interaction in psychosis
Marcelis, Machteld; Cavalier, Etienne ULg; Gielen, Jacques et al

in Acta Psychiatrica Scandinavica (2002), 105(Suppl. 411), 91

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See detailThe metabolic syndrome in children of Province de Luxembourg Belgium.
Guillaume, Michèle ULg; Lapidus, L.; Beckers, F. et al

in Prog 29th Annual Meeting of the European Diabetes Epidemiology Study Group of the EASD (1994)

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See detailThe metabolic syndrome is a risk factor for postoperative obstructive apnoea and hypoxaemia in morbidly obese patients: 5AP3-1
Devillers, H.; HANS, Grégory ULg; Brichant, Jean-François ULg et al

in European Journal of Anaesthesiology (EJA) (2014), 31

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See detailMetabolic variability in bioprocessing : implications of microbial phenotypic heterogeneity
Delvigne, Frank ULg; Zune, Quentin ULg; Lara, Alvaro et al

in Trends in Biotechnology (in press)

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See detailMetabolically healthy overweight and obesity
Esser, Nathalie ULg; SCHEEN, André ULg; PAQUOT, Nicolas ULg

in Annals of Internal Medicine (2014), 160(7), 514

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See detail"Metaboliquement obeses" sans exces de poids: un phenotype interpellant.
Beck, Emmanuel ULg; Scheen, André ULg

in Revue Médicale de Liège (2009), 64(1), 14-22

Obesity, especially abdominal obesity, is the main risk factor of metabolic syndrome. However, there are obviously non obese individuals who are metabolically abnormal and therefore exposed to an ... [more ▼]

Obesity, especially abdominal obesity, is the main risk factor of metabolic syndrome. However, there are obviously non obese individuals who are metabolically abnormal and therefore exposed to an increased risk of cardiovascular complications. Unfortunately, those persons fail to be detected because of a falsely reassuring body weight. The present paper aims at better understanding the etiopathogenesis and pathophysiology of this particular phenotype, at evaluating its potential clinical consequences and at describing the main principles of its therapeutic management. [less ▲]

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See detailMetabolising risk: food scares and the un/re-making of Belgian beef
Stassart, Pierre M ULg; Whatmore, Sarah J.

in Environment & Planning A (2003), 35

In this paper we explore the event of foodscares as an example of what Callon calls 'hot situations', in which the landscape of competing knowledge claims is at its most molten, and alternative production ... [more ▼]

In this paper we explore the event of foodscares as an example of what Callon calls 'hot situations', in which the landscape of competing knowledge claims is at its most molten, and alternative production and consumption practices galvanise new modes of sense-making against the market and state-sanctioned rationalities of industrialisation. Through a case study of the Belgian cooperative Coprosain and its meat products, we examine the 'stuff' of food as a ready messenger of connectedness and affectivity in which 'risk' is transacted as a property both of the growing distance between the spaces of production and consumption and of the enduring metabolic intimacies between human and nonhuman bodies. [less ▲]

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See detailMetabolism of human articular chondrocytes cultured in alginate beads. Longterm effects of interleukin 1 beta and nonsteroidal antiinflammatory drugs
Sanchez, Christelle ULg; Mateus, Marguarita; Defresne, Marie-Paule ULg et al

in Journal of Rheumatology (2002), 29(4), 772-782

OBJECTIVES: To investigate the longterm effects (12 days) of nonsteroidal antiinflammatory drugs [NSAID: aceclofenac (ACECLO), sodium diclofenac (DICLO), indomethacin (INDO), nimesulide (NIM), rofecoxib ... [more ▼]

OBJECTIVES: To investigate the longterm effects (12 days) of nonsteroidal antiinflammatory drugs [NSAID: aceclofenac (ACECLO), sodium diclofenac (DICLO), indomethacin (INDO), nimesulide (NIM), rofecoxib (ROFE), celecoxib (CELE), piroxicam (PIROX), and ibuprofen (IBUP)] on the metabolism of human chondrocytes cultured in alginate beads. METHODS: Enzymatically isolated osteoarthritic (OA) chondrocytes were cultured in alginate beads in a well defined culture medium for 12 days. The DNA content was measured according to a fluorimetric method and cell proliferation was determined by the incorporation of 3H-thymidine in the newly synthesized DNA. Interleukin 6 (IL-6) and IL-8, stromelysin [matrix metalloproteinase-3 (MMP-3)], and aggrecan (AGG) production were assayed by specific enzyme amplified sensitivity immunoassays, and prostaglandin E2 (PGE2) production by specific radioimmunoassay. All NSAID were tested at the mean peak plasma concentration (Cmax) obtained after oral administration of a therapeutic dose. RESULTS: In alginate beads, chondrocytes synthesized high amounts of AGG, which were largely (98%) immobilized in the alginate matrix. A large amount (43%) of the IL-8 produced was stored in the alginate beads, whereas almost all IL-6 production (94%) was released in the culture supernatant. At the therapeutic concentration, all NSAID tested fully blocked PGE2 production. ACECLO, DICLO, INDO, NIM significantly inhibited basal and IL-1beta stimulated IL-6 production; CELE and IBUP only inhibited IL-1beta stimulated IL-6 production; and ROFE and PIROX had no significant effects. No NSAID showed significant effects on basal and IL-1beta stimulated IL-8 production, except CELE and IBUP, which slightly increased basal IL-8 production. ACECLO and INDO increased AGG content by 25% in the alginate beads, while the other NSAID were without significant effect. No NSAID were able to modify the inhibitory effect of IL-1beta on AGG production. NSAID did not modify MMP-3 production. CONCLUSION: The mechanism of action of NSAID seems to be multifactorial and not limited to the inhibition of cyclooxygenases. Further, in our culture conditions, at the Cmax and by comparison with other NSAID, ACECLO and INDO show an advantageous activity profile. They fully blocked PGE2 production, inhibited IL-6 synthesis, and increased aggrecan synthesis. These effects appear advantageous for the longterm treatment of chronic joint diseases such as osteoarthritis. [less ▲]

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See detailMetabolism of no carrier added 2-[18F]fluoro-L-tyrosine in free moving rats.
Aerts, Joël ULg; Plenevaux, Alain ULg; Lemaire, Christian ULg et al

in Journal of Labelled Compounds & Radiopharmaceuticals (1997), 40

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