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See detailThe inhibitor thiomandelic acid binds to both metal ions in metallo-beta-lactamase and induces positive cooperativity in metal binding.
Damblon, Christian ULg; Jensen, Mikael; Ababou, Abdessamad et al

in Journal of Biological Chemistry (2003), 278(31), 29240-51

Thiomandelic acid is a simple, broad spectrum, and reasonably potent inhibitor of metallo-beta-lactamases, enzymes that mediate resistance to beta-lactam antibiotics. We report studies by NMR and ... [more ▼]

Thiomandelic acid is a simple, broad spectrum, and reasonably potent inhibitor of metallo-beta-lactamases, enzymes that mediate resistance to beta-lactam antibiotics. We report studies by NMR and perturbed angular correlation (PAC) spectroscopy of the mode of binding of the R and S enantiomers of thiomandelic acid, focusing on their interaction with the two metal ions in cadmium-substituted Bacillus cereus metallo-beta-lactamase. The 113Cd resonances are specifically assigned to the metals in the two individual sites on the protein by using 113Cd-edited 1H NMR spectra. Each enantiomer of thiomandelate produces large downfield shifts of both 113Cd resonances and changes in the PAC spectra, which indicate that they bind such that the thiol of the inhibitor bridges between the two metals. For R-thiomandelate, this is unambiguously confirmed by the observation of scalar coupling between Halpha of the inhibitor and both cadmium ions. The NMR and PAC spectra reveal that the two chiral forms of the inhibitor differ in the details of their coordination geometry. The complex with R-thiomandelate, but not that with the S-enantiomer, shows evidence in the PAC spectra of a dynamic process in the nanosecond time regime, the possible nature of which is discussed. The thiomandelate complex of the mononuclear enzyme can be detected only at low metal to enzyme stoichiometry; the relative populations of mononuclear and binuclear enzyme as a function of cadmium concentration provide clear evidence for positive cooperativity in metal ion binding in the presence of the inhibitor, in contrast to the negative cooperativity observed in the free enzyme. [less ▲]

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See detailInhibitors of cannabinoid receptors and glucose metabolism.
Scheen, André ULg; Paquot, Nicolas ULg

in Current Opinion in Clinical Nutrition & Metabolic Care (2008), 11(4), 505-11

PURPOSE OF REVIEW: Abdominal obesity is closely related to type 2 diabetes and overactivity of the endocannabinoid system. The present review aims at evaluating the role of endocannabinoid system in ... [more ▼]

PURPOSE OF REVIEW: Abdominal obesity is closely related to type 2 diabetes and overactivity of the endocannabinoid system. The present review aims at evaluating the role of endocannabinoid system in glucose dysregulation and the effects of cannabinoid 1 receptor blockade on glucose metabolism in both animal models and overweight/obese humans, especially with type 2 diabetes. RECENT FINDINGS: Cannabinoid 1 receptors have been identified not only in the brain, but also in the adipose tissue, the gut, the liver, the skeletal muscle and even the pancreas, all organs playing a key role in glucose metabolism and type 2 diabetes. Rimonabant, the first selective cannabinoid 1 receptor blocker in clinical use, has been shown to reduce body weight, waist circumference, glycated haemoglobin, triglycerides, insulin resistance index, and to increase HDL cholesterol and adiponectin concentrations in patients with type 2 diabetes, confirming data on nondiabetic overweight/obese patients. Almost half of the metabolic changes, including glycated haemoglobin reduction, could not be explained by weight loss, in agreement with direct peripheral effects. SUMMARY: Cannabinoid 1 blockade reduces food intake and body weight and improves metabolic regulation beyond just weight loss. Because of its positive effect on glucose metabolism, rimonabant deserves consideration in the treatment of overweight/obese patients with type 2 diabetes. [less ▲]

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See detailInhibitors of glycosylhydrolases as potential insecticides : focus on aphid model
Bosquée, Emilie ULg; Vandermoten, Sophie; Richel, Aurore ULg et al

Poster (2014, June)

Beside conventional neurotoxic compounds, new kinds of insecticides are investigated and new specific targets are in current research. According to the energy metabolic pathway, several enzymes are ... [more ▼]

Beside conventional neurotoxic compounds, new kinds of insecticides are investigated and new specific targets are in current research. According to the energy metabolic pathway, several enzymes are interesting to bring potential specific control of arthropods. Indeed, glycosylhydrolase group is very diversified from glucanases to trehalases, until chitinases. Different kinds of inhibitors were here tested to determine their potential role as new targetted aphicides. After different assays using the selected inhibitors in artificial diets, the most efficient molecules at 50-100 μg ml-1were kept for further proteomic tasks. The proteome patterns of aphids related to different inhibitor treatments were determined by two dimension electrophoresis, 2D-Differencial In Gel Expression (2D-Dige) coupled with mass spectrometry (ESI-MS-MS and Maldi-Tof-MS-MS) and data bank investigations. Particular proteins of interest were selected and accurately characterised with both fundamental but also applied views. Not only the carbohydrate metabolic pathway was disturbed with the use of glycosylhydolases inhibitors, other primary functions were also modified (amino acid synthesis, stress response, etc). This proteomic approach was discussed as an interesting and reliable tool to study the biologically involved proteins from aphids in response to specific tested enzymatic inhibitors with further ideas to be promoted as new insecticides to control insect pests. [less ▲]

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See detailInhibitors of metallo-beta-lactamase generated from beta-lactam antibiotics.
Badarau, Adriana; Llinas, Antonio; Laws, Andrew P et al

in Biochemistry (2005), 44(24), 8578-89

The resistance of bacteria to the normally lethal action of beta-lactam antibiotics is largely due to the production of beta-lactamases that catalyze the hydrolysis of the beta-lactam. One class of these ... [more ▼]

The resistance of bacteria to the normally lethal action of beta-lactam antibiotics is largely due to the production of beta-lactamases that catalyze the hydrolysis of the beta-lactam. One class of these enzymes is a zinc-dependent metallo-beta-lactamase for which there are no clinically available inhibitors. The hydrolysis of cephalosporin beta-lactam antibiotics generates dihydrothiazines which subsequently undergo isomerization at C6 by C-S bond cleavage and through the intermediacy of a thiol. These thiols can be trapped by the beta-lactamase from Bacillus cereus, causing inhibition of the enzyme. The rate of production of the thiol corresponds to the rate of inhibition, and the inhibition constants are in the micromolar range but vary with the nature of the cephalosporin derivative. NMR studies have identified the structure of the thiols causing inhibition and also show that the thiol binds to the zinc ion, which in turn perturbs the metal-bound histidines. Inhibition is slowly removed as the thiol becomes oxidized or undergoes further degradation. The thiol intermediate generated from cephalothin is a slow binding inhibitor. There is no observed inhibition from the analogous degradation products from penicillins. [less ▲]

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See detailInhibitors of VIM-2 by screening pharmacologically active and click-chemistry compound libraries
Minond, D.; Saldanha, S. A.; Spaargaren, M. et al

in Bioorganic & Medicinal Chemistry (2009), 17

VIM-2 is an Ambler class B metallo-beta-lactamase (MBL) capable of hydrolyzing a broad-spectrum of beta-lactam antibiotics. Although the discovery and development of MBL inhibitors continue to be an area ... [more ▼]

VIM-2 is an Ambler class B metallo-beta-lactamase (MBL) capable of hydrolyzing a broad-spectrum of beta-lactam antibiotics. Although the discovery and development of MBL inhibitors continue to be an area of active research, an array of potent, small molecule inhibitors is yet to be fully characterized for VIM-2. In the presented research, a compound library screening approach was used to identify and characterize VIM-2 inhibitors from a library of pharmacologically active compounds as well as a focused 'click' chemistry library. The four most potent VIM-2 inhibitors resulting from a VIM-2 screen were characterized by kinetic studies in order to determine K(i) and mechanism of enzyme inhibition. As a result, two previously described pharmacologic agents, mitoxantrone (1,4-dihydroxy-5,8-bis([2-([2-hydroxyethyl]amino)ethyl]amino)-9,10-anthracenedione) and 4-chloromercuribenzoic acid (pCMB) were found to be active, the former as a non-competitive inhibitor (K(i)=K(i)(')=1.5+/-0.2microM) and the latter as a slowly reversible or irreversible inhibitor. Additionally, two novel sulfonyl-triazole analogs from the click library were identified as potent, competitive VIM-2 inhibitors: N-((4-((but-3-ynyloxy)methyl)-1H-1,2,3-triazol-5-yl)methyl)-4-iodobenzenesulfonamide (1, K(i)=0.41+/-0.03microM) and 4-iodo-N-((4-(methoxymethyl)-1H-1,2,3-triazol-5-yl)methyl)benzenesulfonamide (2, K(i)=1.4+/-0.10microM). Mitoxantrone and pCMB were also found to potentiate imipenem efficacy in MIC and synergy assays employing Escherichia coli. Taken together, all four compounds represent useful chemical probes to further investigate mechanisms of VIM-2 inhibition in biochemical and microbiology-based assays. [less ▲]

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See detailInhibitory Action Of A New Lectin From Xerocomus Chrysenteron On Cell-Substrate Adhesion
Marty-Detraves, C.; Francis, Frédéric ULg; Baricault, L. et al

in Molecular and Cellular Biochemistry (2004), 258(1-2), 49-55

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See detailInhibitory activity of lactobacillus curvatus CWBI-B28 against Listeria monocytogenes and ST2-verotoxin producing Escherichia coli O157
Ghalfi, H.; Thonart, Philippe ULg; Benkerroum, N.

in African Journal of Biotechnology (2006), 5(22), 2303-2306

A bacteriocin- producing strain of Lactobacillus curvatus CWBI- B28 isolated from raw meat was shown to inhibit Listeria monocytogenes and pathogenic strains of Escherichia coli by the well diffusion ... [more ▼]

A bacteriocin- producing strain of Lactobacillus curvatus CWBI- B28 isolated from raw meat was shown to inhibit Listeria monocytogenes and pathogenic strains of Escherichia coli by the well diffusion assay. To confirm whether the bacteriocin was involved in E. coli O157 inhibition, growth of the pathogen was monitored in the neutralized cell- free supernatant ( NCFS) pre- treated with pronase E or catalase. Alternatively, E. coli O157 ( VH21) was co- cultured with Lb. curvatus CWBI- B28 in MRS broth. The results of the well- diffusion assay suggested that the inhibition of E. coli O157 ( VH21) was partially due to the bacteriocin; however, growth monitoring indicated that such inhibition is exclusively due to hydrogen peroxide. In pronase- added NCFS ( i. e., absence of bacteriocin) the colony forming units ( cfus) of E. coli O157 ( VHA21) declined to below the detectable limit after 24 h of incubation at 37 C. However, in presence of catalase no inhibition of the pathogen was observed and the cfus increased steadily to reach 8 log units in 24 h. Moreover, in co- culture, a significantly accelerated inhibition of E. coli O157 ( VH21) was observed in MRS broth as compared to the NCFS without added catalase and the cfus decreased to below the detectable limit in 8 h instead of 24 h, respectively. [less ▲]

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See detailInhibitory control of memory in normal ageing: Dissociation between impaired intentional and preserved unintentional processes.
Collette, Fabienne ULg; Germain, Sophie ULg; Hogge, Michaël et al

in Memory (2009), 17(1), 104-122

The aim of this study was to compare the performance of elderly and young participants on a series of memory tasks involving either intentional or unintentional inhibitory control of memory content ... [more ▼]

The aim of this study was to compare the performance of elderly and young participants on a series of memory tasks involving either intentional or unintentional inhibitory control of memory content. Intentional inhibition processes in working and episodic memory were explored with directed forgetting tasks and in semantic memory with the Hayling task. Unintentional inhibitory processes in working memory, long-term memory, and semantic memory were explored with an interference resolution task, the retrieval practice paradigm, and the flanker task, respectively. The results indicate that elderly participants' performance on the two directed forgetting tasks and the Hayling task is lower than that of young ones, and that this impairment is not related to their initial memory capacity. This suggests that there is a specific dysfunction affecting intentional inhibitory control of memory contents in normal ageing. [less ▲]

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See detailInhibitory effect of curcuminoids and tetrahydrocurcuminoids on equine activated neutrophils and myeloperoxidase activity
Franck, Thierry ULg; Kohnen, Stephan ULg; Grulke, Sigrid ULg et al

in Physiological Research (2008), 57(4), 577-587

In the horse, the inflammation response to various pathologies (intestinal strangulations, laminitis, etc.) involves an excessive stimulation of the polymorphonuclear neutrophils releasing reactive oxygen ... [more ▼]

In the horse, the inflammation response to various pathologies (intestinal strangulations, laminitis, etc.) involves an excessive stimulation of the polymorphonuclear neutrophils releasing reactive oxygen species (ROS) and myeloperoxidase (MPO). The aim of the present work was to study the effect of natural polyphenols, curcuminoids and tetrahydrocurcuminoids (THC) on isolated stimulated equine neutrophils and on the activity of purified MPO. The ROS production and the release of MPO by activated neutrophils were measured by chemiluminescence and ELISA techniques, respectively. The activity of purified MPO was measured by studying its nitration, chlorination or oxidation capacity and by using an original method called SIEFED allowing the study of drug interaction with the enzyme without interferences of the medium. Curcuminoids and THC had dose-dependent inhibitory effects on ROS production and MPO release by activated neutrophils and on purified MPO activity. We suggest that the higher efficacy of curcuminoids versus THC could be explained, at least partially, by its chemical structure: the conjugated double bounds and the plane structure of curcuminoids made easier the neutralization of the radical species generated by activated neutrophils and the interaction of the drug with the active site of MPO. These inhibitory effects of curcuminoids on the oxidant activity of equine neutrophils and on MPO activity open therapeutic perspectives in equine pathologies with excessive inflammatory reactions. [less ▲]

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See detailInhibitory effect of tricyclic antidepressant drugs on spontaneous activity of noradrenergic neurons - relation with blood and brain concentrations
Scuvée-Moreau, Jacqueline ULg; Fischer, Paul; Dresse, Albert ULg

in Archives Internationales de Physiologie et de Biochimie (1979), 87(1), 134-141

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See detailInhibitory Effects of Proanthocyanidins from Ribes Nigrum Leaves on Carrageenin Acute Inflammatory Reactions Induced in Rats
Garbacki, Nancy ULg; Tits, Monique ULg; Angenot, Luc ULg et al

in BMC Pharmacology (2004), 4(1), 1-9

BACKGROUND: The anti-inflammatory effects of proanthocyanidins (PACs), isolated from blackcurrant (Ribes nigrum L.) leaves, were analysed using carrageenin-induced paw oedema and carrageenin-induced ... [more ▼]

BACKGROUND: The anti-inflammatory effects of proanthocyanidins (PACs), isolated from blackcurrant (Ribes nigrum L.) leaves, were analysed using carrageenin-induced paw oedema and carrageenin-induced pleurisy in rats. RESULTS: Pretreatment of the animals with PACs (10, 30, 60 and 100 mg/kg, i.p.) reduced paw oedema induced by carrageenin in a dose and time-dependent manner. PACs also inhibited dose-dependently carrageenin-induced pleurisy in rats. They reduced (A) lung injury, (B) pleural exudate formation, (C) polymorphonuclear cell infiltration, (D) pleural exudate levels of TNF-alpha, IL-1beta and CINC-1 but did not affect IL-6 and IL-10 levels. They reduced (E) pleural exudate levels of nitrite/nitrate (NOx). In indomethacin treated rats, the volume of pleural exudate was low, its content in leukocytes and its contents in TNF-alpha, IL-1beta, IL-6 and IL-10 but not in NOx were reduced. These data suggest that the anti-inflammatory properties of PACs are achieved through a different pattern from those of indomethacin. CONCLUSION: These results suggest that the main mechanism of the anti-inflammatory effect of PACs mainly lies in an interference with the migration of the leukocytes. Moreover, PACs inhibited in vivo nitric oxide release. [less ▲]

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See detailInhibitory influence of oxytocin infusion on contingent negative variation and some memory tasks in normal men
Geenen, Vincent ULg; Adam, Francine; Baro, Vincent et al

in Psychoneuroendocrinology (1988), 13

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See detailInhomogeneous and anisotropic deformation behavior and strain hardening of ultrafine-grained aluminium by ECAP
Poortmans, Stijn; El Houdaigui, Fouad; Habraken, Anne ULg et al

in Zhu, Y. T.; Langdon, T. G.; Horita, Z. (Eds.) et al Proceedings of the Ultrafine Grained Materials IV Conference (2006)

Hot-rolled AA1050 commercial pure aluminum was deformed by ECAP (Equal Channel Angular Pressing) at room temperature following route BC for 8 passes. Mechanical testing at room temperature on both hot ... [more ▼]

Hot-rolled AA1050 commercial pure aluminum was deformed by ECAP (Equal Channel Angular Pressing) at room temperature following route BC for 8 passes. Mechanical testing at room temperature on both hot-rolled aluminum and aluminum after ECAP consisted of uniaxial tension, axisymmetric compression and shear by torsion. The phenomenological Hill’s criterion identified from texture data accounts for the observed tension-compression asymmetry due to ECAP and predicts torsion yielding close to measurements. FE simulations of the compression tests are performed with a Hill model or a Minty micro-macro model and coupled with an isotropic Voce saturation hardening law. These simulations compute the inhomogeneous behavior due to barreling, the observed sample anisotropy and the force-displacement curve. Comparisons of numerical and experiments results provide a first identification of the hardening parameters and the friction coefficient during compression tests. [less ▲]

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See detailInhumanité de l'état de nature
Delruelle, Edouard ULg

in Allard, Julie; Berns, Thomas (Eds.) Humanités (2005)

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See detailIñigo de Brizuela et Andrés de Soto, deux regards sur la politique
Pirlet, Pierre-François ULg

in II ENCUENTRO DE JÓVENES INVESTIGADORES EN HISTORIA MODERNA - Actos [à préciser] (in press)

Iñigo de Brizuela and Andrés de Soto, both confessors of the Archdukes were key figures at Brussels' court. Each of them used to influence the policy, using different bias. But they weren't trying to ... [more ▼]

Iñigo de Brizuela and Andrés de Soto, both confessors of the Archdukes were key figures at Brussels' court. Each of them used to influence the policy, using different bias. But they weren't trying to reach similar goals: Brizuela carefully acted to preserve Spanish interests in the Catholic Netherlands, while de Soto struggled for a Catholic victory. Their political actions and its reasons will be covered by this paper. [less ▲]

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See detailInitial adherence of EPEC, EHEC and VTEC to host cells.
Bardiau, Marjorie ULg; Szalo, Ioan Mihai ULg; Mainil, Jacques ULg

in Veterinary Research (2010), 41(5), 57

Initial adherence to host cells is the first step of the infection of enteropathogenic Escherichia coli (EPEC), enterohaemorrhagic Escherichia coli (EHEC) and verotoxigenic Escherichia coli (VTEC) strains ... [more ▼]

Initial adherence to host cells is the first step of the infection of enteropathogenic Escherichia coli (EPEC), enterohaemorrhagic Escherichia coli (EHEC) and verotoxigenic Escherichia coli (VTEC) strains. The importance of this step in the infection resides in the fact that (1) adherence is the first contact between bacteria and intestinal cells without which the other steps cannot occur and (2) adherence is the basis of host specificity for a lot of pathogens. This review describes the initial adhesins of the EPEC, EHEC and VTEC strains. During the last few years, several new adhesins and putative colonisation factors have been described, especially in EHEC strains. Only a few adhesins (BfpA, AF/R1, AF/R2, Ral, F18 adhesins) appear to be host and pathotype specific. The others are found in more than one species and/or pathotype (EPEC, EHEC, VTEC). Initial adherence of EPEC, EHEC and VTEC strains to host cells is probably mediated by multiple mechanisms. [less ▲]

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See detailInitial Investigation of Chordwise Flexible Flat Aerofoil
Vio, Gareth A.; Worotynska, Jagoda; Berci, Marco et al

in Proceedings of the 53rd AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference (2012, April 25)

The size of small Unmanned Air Vehicles (UAVs) makes them susceptible to gusts, hence an evaluation of their aeroelastic performance is a necessary requirement. With advances in materials, new aircraft ... [more ▼]

The size of small Unmanned Air Vehicles (UAVs) makes them susceptible to gusts, hence an evaluation of their aeroelastic performance is a necessary requirement. With advances in materials, new aircraft are ever lighter and more flexible, both in the span-wise and chord-wise direction. An experiment is set up to evaluate the aeroelastic performance of a 2D chord-wise aerofoil structure under gust loading, where the wing of a small Unmanned Air Vehicle (UAV) is considered by coupling a Finite Element (FE) structural model with a Doublet-Lattice Method (DLM) aerodynamic model; a new semi-analytical modelling approach is also described. The flexible aerofoil structure is then optimised by means of a genetic algorithm (GA) framework for the minimum weight, subject to aeroelastic constraints of flutter, divergence and structural displacement. [less ▲]

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See detailAn initial investigation of the magnetosphere at a system level using auroral oval radius and ring current intensity as state variables
Milan, S. E.; Hutchinson, J.; Boakes, P. D. et al

Conference (2009, December 01)

One approach to understanding the magnetosphere at a system level is to select a number of magnetospheric state variables and to examine statistically their inter-relationships and the temporal evolution ... [more ▼]

One approach to understanding the magnetosphere at a system level is to select a number of magnetospheric state variables and to examine statistically their inter-relationships and the temporal evolution of the magnetosphere through state-space. This talk outlines a first attempt at such a study, using the radius of the auroral oval, a proxy for the open flux content of the magnetosphere, and the Sym-H index, a measure of the intensity of the ring current, as the primary state variables. Using observations from the two-year period June 2000 to May 2002, the response of the state of the magnetosphere to differing solar wind inputs, and the evolution of the system state during geomagnetic storms is investigated. Our main finding is a characteristic evolution of magnetospheric state through the initial, main, and recovery phases of geomagnetic storms. We discuss our findings within the context of the expanding/contracting polar cap paradigm, in terms of a modification of substorm onset conditions by the magnetic perturbation associated with the ring current. [less ▲]

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