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See detailESR evidence of superoxide anion, hydroxyl radical and singlet oxygen generation during photosensitization of PPME in HCT-116 cells
Quoilin, Caroline ULg; Guelluy, Pierre-Henri ULg; Grammenos, Angeliki ULg et al

Poster (2010, March)

Pyropheophorbide-a methyl ester (PPME), a derivative of chlorophyll a, is a second-generation photosensitizer and is studying largely in vitro for nearly a decade on cancerous cells. It has been ... [more ▼]

Pyropheophorbide-a methyl ester (PPME), a derivative of chlorophyll a, is a second-generation photosensitizer and is studying largely in vitro for nearly a decade on cancerous cells. It has been previously established on HCT-116 (human colon carcinoma cell line) that PPME is a molecule able to create apoptotic and necrotic death (Matroule et al). The cytotoxicity of PPME is presumed to be induced by reactive oxygen species (ROS) generated by the photoexcited molecule. Actually, to the best of our knowledge, no experimental evidence enables to confirm this supposition in an indubitable manner. Electron spin resonance (ESR) associated with spin trapping technique is a powerful method to detect, quantify and identify the ROS produced after photoactivation of PPME. Previous results indicate that PPME penetrates inside cells and localizes inside specific organelles (endothelial reticulum, Golgi apparatus and lysosome) (Matroule et al). The recent researches of Guelluy et al have also clearly demonstrated the presence of PPME inside mitochondrion. Consequently, ESR experiments were performed using an intracellular located spin trap, POBN (4-pyridyl 1-oxide-N-tert-butylnitrone), in order to detect in situ the ROS production. It has been shown that PPME is able to generate superoxide anions and hydroxyl radicals. Irradiation of the dye in HCT-116 cells in the presence of POBN spin trap and ethanol scavenger (2%, a non-toxic concentration) leads to the apparition of the ESR spectrum characteristics of POBN/ethoxy adduct. To assess the extent of contribution of ROS and to determine a possible reaction mechanism, competition experiments with specific quencher agents were carried out. Addition of catalase (CAT), a hydrogen peroxide quencher, or superoxide dismutase (SOD), a superoxide anion quencher, inhibits 30% of the signal. The parallel effect of SOD and CAT suggest that superoxide anion and hydrogen peroxide are involved in the generation of hydroxyl radicals via a Fenton reaction. This assertion is reinforced by the 20% reduction of signal intensity when adding desferroxamine, a Fe3+ chelator also implicated in Fenton reaction. Addition of DABCO, a quencher of singlet oxygen, to cells reduces 70% of the POBN/ethoxy adduct signal intensity. [less ▲]

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See detailStudy of the role of miR-21 in the regulation of angiogenesis
Sabatel, Céline; Malvaux, Ludovic; Bovy, Nicolas ULg et al

Poster (2010, March)

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See detail16K human prolactin is an anti-lymphangiogenic factor in vitro and in vivo
Kinet, Virginie; Castermans, Karolien; Blacher, Silvia ULg et al

Poster (2010, March)

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See detailHYPERINSULINISM-HYPERAMMONEMIA: AN UNUSUAL CAUSE OF HYPOKETOTIC HYPOGLYCEMIA
HARVENGT, Julie ULg; LEBRETHON, Marie-Christine ULg; leroy, patricia et al

Poster (2010, March)

BACKGROUND Etiological diagnosis of hypoglycaemia in infancy is a complex process, requiring careful integration of detailed history, clinical and laboratory data. The causes of recurrent infant ... [more ▼]

BACKGROUND Etiological diagnosis of hypoglycaemia in infancy is a complex process, requiring careful integration of detailed history, clinical and laboratory data. The causes of recurrent infant hypoglycaemia include excessive insulin secretion, surreptitious insulin administration, deficiency of counter-regulatory hormones and inborn errors of metabolism. CLINICAL CASE A 10 month old girl was admitted at our emergency unit for generalized seizures without fever. Routine laboratory investigations were normal but blood glucose level was at 31 mg/dl. No ketone bodies were found in the urine. Past medical history revealed failure to thrive. A first seizure episode at 8 months of age during family’s holiday is reported. Tests performed in a foreign hospital revealed glycaemia at 36mg/dl. During her stay in our paediatric unit, several hypoglycaemias (31-45 mg/dl) were documented related to irritability as initial symptom of neuroglucopaenia. Detailed medical history revealed that fast tolerance was shorten with hypoglycaemia documented between one to three hours after eating. Clinical examination showed absence of hepatomegaly and failure to thrive: weight, -3SD; height, -2SD, and cranial circumference -2SD. At the time of hypoglycaemia, urinary tests revealed absence of ketonuria, that basically evokes hyperinsulinism or fatty acid oxidation deficiencies but these deficiencies were rapidly excluded by the very short fast state. Blood acylcarnitine profile was normal. Hyperinsulinism is defined by a ratio glycaemia/insulin below 4 with insulin values not necessary high. Since hyperinsulinism can not be excluded with only one blood measure, series of taking were performed during 24 hours. One of these tests was clearly positive with ratio equal to 2.3 (glycaemia at 41 mg/dl, insulin at 18µU/ml). For this patient, ammonemia was also tested with values ranged from 242 to 275 µg/dl (normal < 125) and the diagnosis of hyperinsulinism/hyperammoniemia (hi/ha) was made and confirmed by molecular analysis (mutation c.965G>A (p.R269H) in the GLUD1 gene). The treatment consists in this case by diazoxide and reduction of leucine intakes (< 200 mg of leucine/meal). DISCUSSION Differential diagnosis of hypoglycaemia with absence of ketonuria and absence of hepatomegaly include fatty acids β-oxidation defects, ketogenesis defects and hyperinsulinisms. Short fasting and post-prandial induced hypoglycaemia pointed to hyperinsulinism in our patient. Congenital hyperinsulinism includes KATP, glucokinase or glutamate deshydrogenase mutations. Hi/ha syndrome is due to activating mutations in the GLUD1 gene, coding for the glutamate dehydrogenase (GDH). Such mutations reduce the sensitivity of the enzyme to allosteric inhibition by GTP and consequently increase its sensitivity to allosteric activation by L-leucine. Hyperactivity of the GDH is responsible for over-oxidation of glutamate in β-pancreatic cells, increase of the ATP/ADP ratio and insulin release. Hyperactivity of GDH in liver is also responsible for hyperammonemia, which is usually mild and considered harmless for the brain. Nevertheless, recent studies have shown an increased epilepsy risk in cohorts of patients with hi/ha. CONCLUSION This case points out the importance of necessity for first investigations of infant documented case of hypoglycaemia. Patient history must focus on symptoms such as shorten fast tolerance periods and neurological symptoms of glucose deprivation. Blood samples should be taken at the time of hypoglycaemia and urine samples as soon as possible after the episode of hypoglycaemia. Initial normal insulin values do not allow the exclusion of the diagnosis of hyperinsulinism. [less ▲]

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See detailThe Hydrogen Electrode in Ionic Liquids: Acidity Measurements and Titrations
Robert, Thierry ULg; Malherbe, Cédric ULg; Magna, lionel et al

Poster (2010, March)

The acidity level in ILs containing acid was first determined using the Hammett acidity function (H0)1-2 in our laboratory. It was demonstrated that this attainable acidity, extending from -3 to -8, is ... [more ▼]

The acidity level in ILs containing acid was first determined using the Hammett acidity function (H0)1-2 in our laboratory. It was demonstrated that this attainable acidity, extending from -3 to -8, is exclusively depending of the nature of anion and follow the order: PF6 > BF4 > NTf2 > OTf. Nevertheless, the Hammett acidity function is an apparent function in this media and must then be corrected for. Consequently, in a second step, we tried to evaluate directly the proton activity from the determination of a potentiometric acidity function (R0) based on the extrathermodynamic Strehlow assumption.3 Therefore, the equilibrium potential of the H+/H2 couple was measured with an hydrogen electrode versus the ferricinium/ferrocene couple for which the potential is considered as independent of the solvent. [less ▲]

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See detailQuantitative Evaluation of Imputities in Ionic Liquids
Robert, Thierry ULg; Olivier-Bourbigou, Hélène; Gilbert, Bernard ULg

Poster (2010, March)

Since several years, our laboratory is studying the acidity in ionic liquids and showed that very acidic levels can be reached in these media when a strong acid is added. These acidity levels were ... [more ▼]

Since several years, our laboratory is studying the acidity in ionic liquids and showed that very acidic levels can be reached in these media when a strong acid is added. These acidity levels were determined using Hammett acidity1 (spectroscopic method) and Strehlow acidity2 (potentiometric method) measurements. Considering the attainable acidity levels, it turns out that the purity of these ionic solvents is very critical because all impurities (i.e methylimidazole, water, acetone, chloride …) can act as (strong) bases. Therefore, it is imperative to quantify these impurities to obtain reproducible results. [less ▲]

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See detailFaraday instability on a network
Delon, Giles ULg; Terwagne, Denis ULg; Adami, Nicolas ULg et al

Poster (2010, March)

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See detailComparing deviancy training in three groups of adolescents : qualitative and quantitative data
Mathys, Cécile ULg; Born, Michel; Shaw, Daniel

Poster (2010, March)

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See detailAn analytical method to determine the composition of cryolitic melts involved in the Hall-Heroult process by Raman spectroscopy
Malherbe, Cédric ULg; Gilbert, Bernard ULg

Poster (2010, March)

The Hall-Héroult process involves the metallic aluminium production from electroreduction of aluminium oxide in cryolitic melt (mostly composed of cryolite and aluminium fluoride) around 1000°C. In order ... [more ▼]

The Hall-Héroult process involves the metallic aluminium production from electroreduction of aluminium oxide in cryolitic melt (mostly composed of cryolite and aluminium fluoride) around 1000°C. In order to reduce the energy loss during this process, controlling the melt composition turns out to be critical. Unfortunately, no in situ analytical method allows measuring the melt composition yet. Since the Raman spectrum of the melt depends on both the cryolitic ratio (molar NaF/AlF3 ratio, CR) and the aluminium oxide content, our laboratory proposed in the past to apply Raman spectroscopy for direct melt composition determination by recording the spectrum from the top. However, experimental problems made the practical application difficult. Nowadays, the method is becoming more feasible because of new instrumental developments such as new sensitive CCD, fiber optics and new optical filters. [less ▲]

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See detailInvolvement of miR-125b in in vitro and in vivo angiogenesis
Malvaux, Ludovic; Pendeville, Hélène; Sabatel, Céline et al

Poster (2010, March)

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See detailMultifractality in quantum maps
Martin, John ULg; Garcia-Mata, Ignacio; Giraud, Olivier et al

Poster (2010, March)

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See detailAnalyse et évaluation des incidents médicamenteux au CHU de Liège
Bottari, Ludovic; Maesen, Didier ULg; Gerard, Xavier ULg et al

Poster (2010, February 27)

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See detailEnquête sur les besoins et les attentes pour la pharmacie clinique au CHU de Liège
Gerard, Xavier ULg; Lerusse, Thomas ULg; Van Hees, Thierry ULg

Poster (2010, February 27)

Résultats d'un enquête auprès des médecins et des infirmiers chef d'unité sur la perception, les besoins et les attentes à propos de la pharmacie clinique au CHU de Liège.

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See detailPoleward front of upwelling filaments generates subsurface anticyclonic eddies (FEDDY): a CAIBEX Project contribution
Sangrà, Pablo; Arístegui, Javier; Troupin, Charles ULg et al

Poster (2010, February 25)

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See detailModeling and observation of an upwelling filament off Cape Ghir (NW Africa) during the CAIBEX survey
Troupin, Charles ULg; Sangrà, Pablo; Arístegui, Javier et al

Poster (2010, February 22)

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See detailEnzymatic process development for the extraction of ferulic acid from wheat bran
Giet, Jean-Michel ULg; Roiseux, O.; Blecker, Christophe ULg

Poster (2010, February 16)

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See detailBrushes of Polymers Bearing Negatively Charged Side Groups: Mimicking Natural Molecular Velcros
Hou, W.; Fustin, C.-A; Theato, P. et al

Poster (2010, February 05)

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See detailPretreatments and enzymatic hydrolysis of Miscanthus x giganteus for oligosaccharides production: delignification degree and characterisation of the hydrolysis products
Vanderghem, Caroline ULg; Jacquet, Nicolas ULg; Blecker, Christophe ULg et al

Poster (2010, February 04)

The aim of the present study is to compare two delignification methods (formic/acetic acid1 and soaking in aqueous ammonia) on Miscanthus x giganteus and to assess the suitability to produce cellobiose ... [more ▼]

The aim of the present study is to compare two delignification methods (formic/acetic acid1 and soaking in aqueous ammonia) on Miscanthus x giganteus and to assess the suitability to produce cellobiose and other oligosaccharides after enzymatic hydrolysis. Oligosaccharides have recently gotten attention for their health benefits. Two methods were compared in order to quantify lignin: the acid detergent lignin method (procedure of Van Soest most commonly employed by animal scientist and agronomists for analysis of forages) and the Klason lignin procedure. Lignin concentrations in raw material determined by both methods were different; Klason lignin value (23.5%) was greater than the acid detergent lignin concentration (12.9%). Possible reasons of these results will be discussed. Pretreatment by the formic/acid mixture showed a better deliginification rate compared to the soaking in aqueous ammonia method. Results were based on Klason lignin. Analysis of the structural carbohydrates revealed that untreated miscanthus was mainly composed of glucose and xylose. Extracted pulps by both delignification methods were hydrolysed by commercial cellulases and hemicellulases. A major challenge is the characterisation of complex mixtures of lignocellulosic hydrolysates. In this study, the hydrolysis products were separated and quantified by highperformance anion exchange chromatography with pulsed amperometric detection (HPAECPAD). This method was successfully applied to the quantitative analysis of monosaccharides (glucose and xylose) and disaccharides (cellobiose and xylobiose) formed by the enzymatic hydrolysis of pretreated miscanthus. The influence of the pretreatments on the oligosaccharides yields will be presented. [less ▲]

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See detailLife cycle environmental performance of using substitution fuels in cement production
Belboom, Sandra ULg; Halleux, Hubert; Léonard, Angélique ULg et al

Poster (2010, February 01)

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See detailA life-cycle assessment of injectable drug primary packaging : comparing the traditional process in glass vials with the new Closed Vial technology (polymer vials)
Belboom, Sandra ULg; Renzoni, Roberto ULg; Verjans, Benoît et al

Poster (2010, February 01)

This study based on the life cycle assessment methodology compares environmental impacts of two packaging alternatives used for injectable drugs: the traditional method based on glass vials and the new ... [more ▼]

This study based on the life cycle assessment methodology compares environmental impacts of two packaging alternatives used for injectable drugs: the traditional method based on glass vials and the new method developed by Aseptic Technologies based on polymer vials. [less ▲]

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See detailTranscriptomic analysis of Arabidopsis roots during flowering
D'Aloia, Maria ULg; Tocquin, Pierre ULg; Périlleux, Claire ULg

Poster (2010, February)

Contribution of the root system to the flowering process remains poorly studied. Part of the problem resides in its difficult isolation from the substrate, especially on adult plants. Taking advantage of ... [more ▼]

Contribution of the root system to the flowering process remains poorly studied. Part of the problem resides in its difficult isolation from the substrate, especially on adult plants. Taking advantage of an hydroponic device that allows synchronous growth and flowering of Arabidopsis thaliana (Tocquin et al., 2003), we performed global transcript profiling of roots during induction of flowering by a single long day (LD). Results were validated by real-time RT-PCR, and the expression patterns of selected probes were further analyzed in shoots and roots. Some of the genes that were identified in the microarray experiment were already known to be involved in the photoperiodic pathway of flowering in Arabidopsis, and hence were activated in both roots and shoots during the LD. These genes include, for example, components of light signaling or circadian machinery (e.g. GIGANTEA). Other genes providing new insights into the control of flowering at the whole plant level will be presented. Tocquin et al., (2003). BMC Plant Biology, 3: 2. [less ▲]

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See detailAN NMR INVESTIGATION OF THE ACTINIDE IONS AND THEIR COMPLEXES
Vidick, Geoffrey ULg; Bouslimani, Nouri; Desreux, Jean-François ULg

Poster (2010, January 28)

We currently use several advanced NMR techniques in order to fully characterize actinide ions and their complexes in water or in organic solvents. The dispersion of the longitudinal relaxation time T1 of ... [more ▼]

We currently use several advanced NMR techniques in order to fully characterize actinide ions and their complexes in water or in organic solvents. The dispersion of the longitudinal relaxation time T1 of solvent nuclei with the magnetic field (NMRD) yields information on the magnetic properties and on the dynamic behavior of paramagnetic species. 17O NMR allows the measurement of the water exchange times and 1H and 13C spectra yield information on the solution structures of the complexes and on the covalency of their coordination bonds. The application of NMR in actinide science will be illustrated with studies on the U, Np, Pu and Cm ions in different oxidation states and on their complexes. For instance, Cm3+ ion is the actinide analogue of Gd3+ but is not in a pure 8S state as indicated by much lower relaxation rates and much shortened electronic relaxation rates. In keeping with EPR studies1, Cm3+ does not have a perfectly spherical distribution of its unpaired electronic spins because of a much stronger spin-orbit coupling. Moreover, the Cm3+ relaxivity originates from three different processes: a dipolar coupling between the nuclear and electronic spins, a delocalization of unpaired electronic spins into the solvent orbitals (contact interaction) and a Curie contribution. Each process gives rise to an inflection point in the NMRD curves and the contact interaction reflects the partial covalency of the coordination bonds formed by Cm3+. A contact contribution is also observed in the NMR spectra of Cm3+ complexes. The sensitivity of NMR to the exact nature of the ground state of actinide ions is also illustrated by detailed studies on the U, Np and Pu ions in different oxidation states. For instance, a comparison of the NMRD curves of the 5f2 ions U4+, NpO2+ and PuO22+ indicates that the two dioxo cations have abnormally long electronic relaxation times. However, well-resolved 1H NMR spectra of their complexes can be obtained provided the solution species are sufficiently rigid. It will be shown that NpO2+ and PuO22+ induce dipolar paramagnetic shifts from which the solution structure can be deduced. [less ▲]

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See detailNOD2 interactome
Lecat, Aurore ULg; Di Valentin, Emmanuel ULg; Fillet, Marianne ULg et al

Poster (2010, January 28)

Detailed reference viewed: 31 (12 ULg)
See detailFunctional study of Arabidopsis thaliana ASF/SF2-like pre-mRNA SR splicing factors
Stankovic, Nancy ULg; Tillemans, Vinciane; Hanikenne, Marc et al

Poster (2010, January 26)

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See detailExpression of the metal homeostasis gene FRD3 in two Arabidopsis species
Charlier, Jean-Benoit ULg; Polese, Catherine; Motte, Patrick ULg et al

Poster (2010, January 26)

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See detailIdentification, characterization and expression profiling of the tomato gene TomLoxF
Mariutto, Martin ULg; Duby, Franceline ULg; Adam, Akram et al

Poster (2010, January 26)

Detailed reference viewed: 32 (10 ULg)
See detailFood and feeding of Limnothrissa miodon and Lamprichthys tanganicanus in Lake Kivu
Masilya, M Pascal; Isumbisho, Mwapu Pascal; Darchambeau, François ULg et al

Poster (2010, January 13)

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See detailModelling total soil respiration in agricultural soils.
Buysse, Pauline ULg; Goffin, Stéphanie; Carnol, Monique ULg et al

Poster (2010, January 12)

Soil respiration is a process which results in CO2 release from the soil to the atmosphere. It comprises two main components. The first one is heterotrophic respiration: CO2 is produced by soil ... [more ▼]

Soil respiration is a process which results in CO2 release from the soil to the atmosphere. It comprises two main components. The first one is heterotrophic respiration: CO2 is produced by soil microorganisms while decomposing the substrate. The second one is autotrophic respiration in which CO2 originates from roots and rhizospheric organisms. All the CO2 is then transported to the surface by diffusion (see Goffin et al., this session). Many biotic and abiotic factors play a role in soil respiration, making this process complex to analyze and understand. Temperature often appears as the most important driving variable. Besides that, interest in the future CO2 emissions from agricultural soils has been growing. Indeed, these ecosystems are a major concern from environmental, economic and social points of view. In particular, the choice of cultural practices and residue management techniques has a strong influence on CO2 emissions from agricultural systems. This work aims at getting to a better understanding of soil respiration in agricultural soils. To reach this goal, many semi-mechanistic models have been previously developed at very different spatio-temporal scales. We intend to adapt such an existing model to crop soils, within a spatial scale of a cultivated field and an annual temporal scale. The model will be validated by using flux measurements carried out at three different crop sites situated in the Hesbaye region in Belgium (Lonzée) and in the South West of France (Lamasquère, Auradé). The study was focused first on soil heterotrophic respiration. Within this part, short term sensitivity of this component to temperature was studied by means of a laboratory incubation experiment. This one was performed with soil samples taken at the Lonzée site. Among the many interesting results we got, it showed a clear sensitivity of soil heterotrophic respiration to short term temperature changes. In parallel, the soil heterotrophic model was calibrated on soil chamber measurements taken at the Lonzée site (Belgium). Next steps in this part of the work will be to calibrate the model using the data from the French sites, and finally to validate the model on the three sites. Afterwards, an autotrophic respiration submodel will be implemented and the results compared to field measurements carried out at the three sites. A further development could consist in simulating agricultural practices to take their impacts on CO2 emissions from crops into account. [less ▲]

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See detailCan an Electronic Nose Assess the Biomethanation Process?
Adam, Gilles ULg; Nicolas, Jacques ULg

Poster (2010, January 12)

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See detailElectrical resistivity tomography and self-potential methods as a tool for fractured aquifer characterization and monitoring
Robert, Tanguy ULg; Nguyen, Frédéric ULg

Poster (2010, January 12)

Electrical resistivity tomography (ERT) and self-potential (SP) investigations are currently conducted in carboniferous limestones in Belgium. The aims of this study are (1) to characterize and (2) to ... [more ▼]

Electrical resistivity tomography (ERT) and self-potential (SP) investigations are currently conducted in carboniferous limestones in Belgium. The aims of this study are (1) to characterize and (2) to monitor the groundwater flow in fractured or karstic area and (3) to use these geophysical data as a help for groundwater flow model conceptualisation and inverse calibration. Large ERT profiles (320 meters) allow us to image the electrical resistivity distribution of the first 60 meters of the subsurface and to detect and characterize (in terms of direction, width and depth) some fractured and/or karstic zones expected to be less resistive. Data errors as well as indicators of resolution (resolution matrix, sensitivity matrix and DOI index) are analysed in order to calculate the depth of investigation of ERT and to avoid the misinterpretation of the resulting images. Self-potential measurements are performed along the electrical profiles and permit us to find some negative anomalies possibly related with groundwater preferential flow pathways. Since SP signals are related with the groundwater flow when taking into account the electrokinetic effect, we are able to estimate a first distribution of the water table along our profiles. These geophysical data concurrently with ‘ground truth’ geological and hydrogeological data give us a way to better understand the groundwater flow in limestone synclines of the Dinant Synclinorium geological structure. Still, further efforts are needed (1) to fully cover the syncline area and (2) to couple the SP, ERT and hydrogeological data through a more complex forward model of the electrokinetic effect of the self-potential method. [less ▲]

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See detailImage Appraisal Tools for Electrical Resistivity Tomography
Caterina, David ULg; Beaujean, Jean ULg; Robert, Tanguy ULg et al

Poster (2010, January 12)

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See detailModelling of Forest Trees Autecology. An applied research at the Walloon Region scale (Belgium)
Ridremont, François ULg; Claessens, Hugues ULg; Lejeune, Philippe ULg et al

Poster (2010, January 12)

Three reasons have urged the Walloon Forest Administration (Walloon Public Service) on to solicit the help of forest researchers to bring practical responses to the adaptation of its current forests ... [more ▼]

Three reasons have urged the Walloon Forest Administration (Walloon Public Service) on to solicit the help of forest researchers to bring practical responses to the adaptation of its current forests management: (i) the progression of research in applied autecology, (ii) the development of software for the management and the analysis of georeferenced data (GIS technologies) and, (iii) the awareness of the potential negative impacts of climate change on forests. To answer to this request, this research aims to model the autecology of the main forest tree species at the Walloon Region scale (Beech, Oak, Norway Spruce, Douglas-fir and valuable broadleaves species). The results will be used to update current practical tools to assess the adequacy of forest tree species on sites, especially in the climate change context. The research is built into three main steps: • update the autecology knowledge for the targeted forest tree species through a state of the art; • compile and create different ecological parameters that can explain the major part of trees growth such as climatic, topographic, geologic, edaphic and phytosociological data gathered from forest plots or geodatabases. In the context of climate change, a particular attention will be brought on bioclimatic and soil moisture conditions because of their narrow link with the potential risk of trees ecophysiological stress; • model tree species reaction to environmental conditions with tree growth indicators. Three types of indicators with different spatio-temporal scales are foreseen: stand site index (30-50 years), periodic diameter growth (5-10 years) and tree-ring growth (1-3 years). The use of these three scales is justified by the interest presented by their cross-validations which are necessary for an accurate extrapolation of results to the entire region. Results should indicate the tree species behaviour, especially towards stress conditions. The integration of climatic data, provided by global climate models based on IPCC's climate scenarios, in autecological models could be used to assess the behaviour of forest stands in future climate conditions. From those results, we expect to identify and assess accurately the risky “sites-species pairs” to avoid in the context of a sustainable silviculture. Finally, results will be used to provide autecological synthesis and practical tools to help forest managers and foresters to identify the best “site-species pairs” (tree-site adequacy maps, sites catalogue and computer platform). [less ▲]

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See detailAnalysis of aldehydes relaesed by rice flour using sorbent adsorption and thermal desorption - gas chromatography/mass spectrometry: Development and validation
Mertens, Cécile ULg; Marlet, Christelle ULg; Blecker, Christophe ULg et al

Poster (2010, January)

Odor is an essential characteristic and a quality marker in baby foodstuff, like a partially hydrolyzed and pregelatinized rice flour. The rice flour study by active sampling and TD-GC/MS highlighted the ... [more ▼]

Odor is an essential characteristic and a quality marker in baby foodstuff, like a partially hydrolyzed and pregelatinized rice flour. The rice flour study by active sampling and TD-GC/MS highlighted the presence of three aldehydes: Hexanal, Octanal, Nonanal. These compounds are known to be caused by lipid oxidation, one of the major alteration reactions in food. The Method was developed and valited on a large range for the three aldehydes. It was then applied to the rice fllour to determine if it can be used to follow the effect of ageing on the aldehydes production. [less ▲]

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See detailHarmonia axyridis (Pallas) secondary metabolites quantification in relation with aposematism : Part II : Pyrazine quantification
Fischer, Christophe ULg; Heuskin, Stéphanie ULg; Marlet, Christelle ULg et al

Poster (2010, January)

The main objective of this study is to investigate the presence of links between chemical defences and warning signals presented by Harmonia axyridis (Pallas), the multicoloured Asian ladybird (Insects ... [more ▼]

The main objective of this study is to investigate the presence of links between chemical defences and warning signals presented by Harmonia axyridis (Pallas), the multicoloured Asian ladybird (Insects: Coleoptera: Coccinellidae). This second part describes an original quantification method for 2-isopropyl-3-methoxypyrazine (IPMP) by active sampling on thermally desorbed adsorbent (TD) coupled with GC-MS analysis. This highly odorous compound is supposed to be implicated in intra- and interspecific communication. In order to allow harmonine quantification (a defence alkaloid, see Part 1), this method avoid any hemolymph loses by the ladybird (Coccinellids can emit hemolymph when stressed). This method is non-lethal and applicable on one single insect. The quantification method has been validated from 37,5pg to 10 000 pg per adsorbent cartridge. On this range, there is no breakthrough and desorption is complete (>99.4%). At the LOQ (37.5pg/cartridge), the bias is of 20%, but rapidly decreased to less than 5% on the rest of the validated range (100 to 10 000 pg/cartridge). According to AOAC (2006) norm, this method is repeatable but not reproducible. The IPMP emission rate following a stress has been quantified on 80 H. axyridis grouped in four classes on basis of the morph type and the elytra hue. Males and females emission rates did not significantly differ. The mean emission rate is of 707 pg/4h with an extremely high standard deviation of 1766pg/4h due to a great individual variability and a strongly asymmetric distribution of the results. These results and those of the harmonine and colour analysis have been statistically analyzed in order to show potential correlations between these factors. It seems that elytra colour is linked with the insect IPMP emission rate. Individuals with a melanic red colour presented IPMP emission rate significantly lower than other studied colours. The harmonine content does not seem linked to the pyrazine emission rate. [less ▲]

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See detailA fast gas chromatographic method for the study of semiochemical slow release formulations
Heuskin, Stéphanie ULg; Lorge, Stéphanie; Leroy, Pascal ULg et al

Poster (2010, January)

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See detailADDICTION AU MMORPG : QUAND LE REEL EST SOUS L’EMPRISE DU VIRTUEL
Bataille, Stéphanie; Triffaux, Jean-Marc ULg

Poster (2010, January)

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See detailHarmonia axyridis (Pallas) secondary metabolites quantification in relation with aposematism : Part I : Harmonine quantification
Fischer, Christophe ULg; Heuskin, Stéphanie ULg; Laurent, Pascal ULg et al

Poster (2010, January)

These last few years, the multicoloured Asian ladybird, Harmonia axyridis Pallas (Insects: Coleoptera: Coccinellidae), an invasive species, has swiftly spread out in Europe. This aposematic and highly ... [more ▼]

These last few years, the multicoloured Asian ladybird, Harmonia axyridis Pallas (Insects: Coleoptera: Coccinellidae), an invasive species, has swiftly spread out in Europe. This aposematic and highly polymorphic insect is problematic in several ways. It seems to outcompete native coccinellid species; they can group on fruits in vineyards and spoil wine when crushed with grapes; they can aggregate by hundreds in houses to winter. This study aims to investigate the relations between the chemical defences of H. axyridis and warning signals expressed by this bug. To achieve this goal, two original quantification methods of H. axyridis secondary metabolites have been undertaken. The first one allows Fast-GC quantifying harmonine, its main defence alkaloid. The other one permits to determine its emission rate of 2-isopropyl-3-methoxypyrazine, a highly odorous compound probably involved in the communication between individuals and in the aposematism of this insect. This last point will be detailed in another poster. Firstly, a method of extraction, acetylation and purification of harmonine from H. axyridis has been devised to obtain a calibration standard because this molecule is not commercially available. The identity of the extracted compound has been confirmed by mass spectrometry and multidimensional NMR. The GC purity of this N,N-diacetylharmonine is of 100%. During the experiments, its stability in acetone solution at 4°C has been verified. Using this purified molecule, an original method of harmonine quantification has been developed by fast gas chromatography and validated using accuracy profile. The method has been validated for concentrations ranging from 28µg/ml to more than 264µg/ml, with a maximal error risk of 20%. From about 100µg/ml, peaks symmetry decreased, but did not influence the quantification. That accuracy profile validation has been compared with a more classical validation using AOAC (2006) norm, which confirmed the first validation. This method allows quantifying harmonine in one single insect. Harmonine has been quantified in 80 H. axyridis divided into four groups of at least 15 individuals on basis of the morph type and the elytra hue. Males and females harmonine contents did not significantly differ. The mean harmonine content was of 106.6µg/individual with a standard deviation of 80.2µg/individual. The results distribution obtained was not normal and a strong variability between individuals was observed, which explains the high standard deviation. These results and those of the pyrazine and colour analysis have been statistically analyzed in order to show potential correlations between these factors. It would appear that elytra colour is linked with the insect harmonine content. Individuals with a non-melanic orange colour presented harmonine content significantly higher than other studied colours. The harmonine content does not seem linked to the pyrazine emission rate. [less ▲]

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See detailLow detection HPLC – DAD analysis of aldehydes and ketones in indoor air : Development and validation by accuracy profile
Marlet, Christelle ULg; Haesen, Charlotte ULg; Lognay, Georges ULg

Poster (2010, January)

Aliphatic aldehydes and ketones like formaldehyde are reactive volatile compounds and common indoor pollutants. The main sources are tobacco smoke, combustion gases, painting and materials. Theses ... [more ▼]

Aliphatic aldehydes and ketones like formaldehyde are reactive volatile compounds and common indoor pollutants. The main sources are tobacco smoke, combustion gases, painting and materials. Theses compounds also arise from the reaction between unsaturated compounds and oxidative agents. The toxic potential of formaldehyde and other aliphatic/aromatic carbonyl compounds requires the determination of even low amounts of these compounds in indoor air. The present method for indoor monitoring uses adsorption at 2,4-dinitrophenylhydrazine (DNPH)-coated sorbents followed by HPLC-UV/DAD analysis of the extract. Detection limits of 0.1μg/m3 were reached by this method which is sufficient for indoor air monitoring. Three DNPH-derivatives could be separated well on a RP-Amide column followed by UV/DAD-detection at 360 nm. Recovery rates of 70-100 % were determined using liquid spiking method. Validation strategy was intentionally oriented towards the ease of use in routine and the liability of the method rather than extreme performances. For that, the validation by accuracy profile was chosen. The accuracy profile, based on the concept of total error (bias + standard deviation), allows to correctly conclude about the validity of a procedure and thus, guarantees that a known proportion of future results obtained with the method will be included within acceptance limits. For the three tested compounds, formaldehyde, acetaldehyde and acetone, the accuracy profile gave the guarantee that at least 95% of the future results obtained with the validated method will be within the ±25% acceptance limits over the whole concentration range defined. The HPLC parameters were also determinated. The performance of the method was finally evaluated by the analysis of indoor air from new timber frame construction. [less ▲]

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See detailIDENTIFICATION OF METABOLITES IN A HUMAN PLASMA STANDARD REFERENCE MATERIAL BY MULTIPLE GC/MS APPROACHES
Eppe, Gauthier ULg; Benner, Bruce; White, Edward et al

Poster (2010, January)

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See detailImportance of pigtailed macaques (Macaca nemestrina leonina) in seed dispersal: impact on the ecological balance of the tropical rainforest at Khao Yai National Park, Thailand
Albert, Aurélie ULg; Huynen, Marie-Claude ULg; Savini, Tommaso ULg

Poster (2010)

Today, many countries of South-East Asia know about the alarming state of the forests existing on their territory and all agree that it is essential to save the remaining primary forest but also to enable ... [more ▼]

Today, many countries of South-East Asia know about the alarming state of the forests existing on their territory and all agree that it is essential to save the remaining primary forest but also to enable the regeneration of degraded areas, through natural or artificial reforestation. The conservation of tropical rainforests thus passes by the necessity to better understand the plant-animal interactions, and in particular, the seed dispersal process. While following a troop of pigtailed macaques (Macaca nemestrina leonina) accustomed to Man in Khao Yai National park (2 168 km ²), Thailand, we will bring important data relating to these seed dispersers potentially necessary but unfortunately vulnerable. Indeed, this vulnerable but little known species, seems to be essential to maintain forest diversity by dispersing many plant species, particularly those inaccessible to smaller frugivores. First results already show that they disperse many seed species, of all kind of size, in all forest types, from primary forest to secondary forest, thanks to various handling techniques. They also seem to show an adaptation in their daily travels according to resources availability. The next fieldworks will enable us to bring more precision in these results and their temporal variations and thus to conclude on the potential role of Macaca nemestrina in the tropical rainforest regeneration. [less ▲]

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See detailModeling Microbial Cross-contamination in Quick Service Restaurants by Means of Experimental Simulations With Bacillus Spores
Baptista Rodrigues, Ana Lúcia ULg; Crevecoeur, Sébastien ULg; Dure, Remi et al

Poster (2010)

Cross contamination has been frequently mentioned as being in the origin of a wide range of food borne outbreaks. Handling of food is one of the ways through which cross contamination may occur. For many ... [more ▼]

Cross contamination has been frequently mentioned as being in the origin of a wide range of food borne outbreaks. Handling of food is one of the ways through which cross contamination may occur. For many different reasons, quick service restaurants are particularly at risk. Due to its importance, cross contamination via the hands should be taken into consideration when carrying out a quantitative risk assessment. The main goal of this study was to determine transfer rates of bacteria to and via the hands, reduction rates of two hand sanitizing procedures and to apply the results to a quantitative microbial risk assessment model. According to our results, handling of a portion of raw minced meat contaminated at 4.104 cfu leads to the presence of 24 cfu on both hands, 3 cfu on ready-to-eat product (RTE) manipulated with unwashed hands, 1 cfu on RTE manipulated with wiped hands and absence on RTE manipulated with washed hands. This study provides adequate quantitative data for quantitative microbial risk assessment. [less ▲]

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See detailMorphology of the suspensory ligament (interosseous muscle III) of the horse
Shikh Al Sook, Mohamad Khir ULg; Espinosa, Jennifer; Piret, Joëlle ULg et al

Poster (2010)

Introduction: The injuries of the suspensory ligament (SL) are important causes of lameness and financial losses in the equine industry. Ultrasound examination permitted to visualize some parts of the SL ... [more ▼]

Introduction: The injuries of the suspensory ligament (SL) are important causes of lameness and financial losses in the equine industry. Ultrasound examination permitted to visualize some parts of the SL. The significance of “abnormal” findings is however not sufficiently known. Until now, few studies described the relationship between the ultrasonographic appearance and the exact morphology in histological sections. The aim of this study is to develop good techniques for cutting and staining the SL and to improve knowledge about the normal morphology of the SL. Methods: In this study, the SL of eight <sound> horses were collected. The body of the SL was divided in 3 thirds and sampling was realised within each third and between the thirds. The samples were embedded in paraffin or in Tissue-Tek for cryosections. The sections were stained with hematoxylin/eosin or Masson's trichrome. For 3 SL, ultrasounds were performed before sampling. The digital tip was maintained in physiological position owing to a press. Results: Most of the paraffin sections were shredded because of the hardness of the tissue. Cryosection revealed a better preservation of tissues. Only some freezing artifacts (holes) appeared on a few sections. Muscles fibers surrounded by adipose tissue containing blood vessels were present mainly in the proximal and medium third of the SL whereas they were not found in the distal third. The remaining structure look like a tendon and was composed of collagen fibers, stained in green with the Masson's trichrome coloration. Conclusions: This study permitted to develop cutting and staining techniques for the SL and helped to map the adipose, muscular and tendinous parts within the SL. It lays down the bases of subsequent studies that will concern ultrasonographically examined digital tips of sound and pathological horses of different breeds and ages. [less ▲]

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See detailComparison of two drainage flow situations on a gentle forested slope
Heinesch, Bernard ULg; Yernaux, Michel ULg; Aubinet, Marc ULg

Poster (2010)

Drainage flows generated on a gentle slope in stable conditions were analysed at the forested site of Vielsalm (Belgium). Two distinct situations were encountered, one corresponding to vertical ... [more ▼]

Drainage flows generated on a gentle slope in stable conditions were analysed at the forested site of Vielsalm (Belgium). Two distinct situations were encountered, one corresponding to vertical convergence, characterised by a negative vertical velocity at the canopy top, the other corresponding to an equilibrium situation without any vertical movement. The causes of these two distinct flow patterns were analysed. Moreover, combined measurements of vertical velocity above the canopy and horizontal velocity divergence below the canopy were found to comply with the continuity equation: an acceleration of the horizontal flow was indeed observed in the trunk-space in convergence situations while not in equilibrium conditions. These measurements combined with those of the horizontal [CO2] gradient below the canopy were found to met the dilution hypothesis suggested by Aubinet et al.(2003): the horizontal [CO2] gradient was negative in convergence situations while slightly positive in equilibrium conditions. The existence of such patterns allows us to confirm the coherence of advection observations made at the site and help to better understand the mechanisms responsible of night flux exchanges at work in stable conditions in complex terrains. Nevertheless, difficulties were met when trying to obtain reliable estimates of the advection transport terms. The estimation of the vertical velocity in the trunk-space obtained by using the divergence measurements refuted the hypothesis of linearity of the vertical profile of vertical velocity, assumption usually used when computing vertical advection. This problem resulted in a great uncertainty on vertical advection which did not allowed to improve the night-flux estimation by adding advection terms to the turbulent flux and the storage. [less ▲]

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See detailNovel HDAC/DNMT twin inhibitors interfere with angiogenesis
Shiva Shankar, Thammadihalli Veerasangaiah ULg; Sulka, Béatrice; Blacher, Silvia ULg et al

Poster (2010)

DNA methylation and histone deacetylation are two key epigenetic modifications that play central role in regulation of gene expression. Several studies have shown that histone deacetylases (HDAC) and DNA ... [more ▼]

DNA methylation and histone deacetylation are two key epigenetic modifications that play central role in regulation of gene expression. Several studies have shown that histone deacetylases (HDAC) and DNA methyltransferases (DNMT) inhibitors are potent antiangiogenic compounds. Though combination of HDAC and DNMT inhibitors are now being examined in clinical trials of hematological malignancies, very little work has been done to understand the effect of this combination on normal and tumoral angiogenesis. We have designed and tested a family of twin drugs with intrinsic HDAC and DNMT inhibitory activities in relevant models of angiogenesis in vitro (endothelial cells, pericytes and the 3D aortic ring assay) and in vivo (the chick chorioallantoic membrane assay). We have identified a lead compound having quantifiable antiangiogenic effect without cytotoxicity associated with increased global acetylation and decreased DNA methylation levels. This compound is presently used to develop effective approaches to treat cancer by modulating the process of angiogenesis. [less ▲]

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See detailTraces metal inputs in the Misten bog (East Belgium): Level of contamination and spatial variability
Allan, Mohammed ULg; Fagel, Nathalie ULg; De Vleeschouwer, François et al

Poster (2010)

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See detailStudy of mechanical, physical and chemical properties of a-C:H films deposited by reactive magnetron sputtering in DC pulsed mode
Colaux, J. L.; Dumont, D.; Delwigne, T. et al

Poster (2010)

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See detailFeasibility study of a Software Defined Radio and its adaptation to space
Heukemes, Mirko; Rainaut, Laurent; Denis, Amandine ULg et al

Poster (2010)

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See detailObservations of nebulae ejected by massive stars with PACS
Vamvatira-Nakou, Chloi ULg; Royer, P.; Hutsemekers, Damien ULg et al

Poster (2010)

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See detailThe HelpED Study: Degree of Agreement Between Patients, Partners, and Physicians on
Claes, Hubert; Andrianne, Robert ULg; Opsomer, Reinier

Poster (2010)

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See detailCellular engineering of Bacillus subtilis to enhance the biosynthesis of highly active anti fungal lipopeptides
Guy, J.; Guez, Jean-Sébastien; Coucheny, F. et al

Poster (2010)

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See detailThe HelpED Study: Impact of Change in Erection Hardness on the Self-Esteem,
Opsomer, Reinier; Claes, Hubert; Andrianne, Robert ULg

Poster (2010)

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See detailOperational multipartite entanglement classes for symmetric photonic qubit states
Kiesel, N.; Wieczorek, W.; Krins, Stéphanie ULg et al

Poster (2010)

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See detailDesign, implementation, and test of a digitally-controlled electrical power supply for the OUFTI-1 nanosatellite
Kolodziej, Marie; Ledent, Philippe; Thirion, Pierre et al

Poster (2010)

Detailed reference viewed: 31 (2 ULg)
See detailNanobodies as structural probes to investigate the mechanism of fibril formation by the amyloidogenic variants of human lysozyme.
Dumont, Janice ULg; Menzer, Linda ULg; Pardon, Els et al

Poster (2010)

Six variants of human lysozyme (single-point mutations I56T, F57I, W64R, D67H and double mutations F57I/T70N, W112R/T70N) are associated with a hereditary non-neuropathic systemic amyloidose. These ... [more ▼]

Six variants of human lysozyme (single-point mutations I56T, F57I, W64R, D67H and double mutations F57I/T70N, W112R/T70N) are associated with a hereditary non-neuropathic systemic amyloidose. These proteins form extracellular amyloid fibrils that deposit in a wide range of tissues and organs such as liver, spleen and kidneys where they cause damages [1]. It was shown that the D67H and I56T mutations cause a loss in stability and more particularly a loss of global cooperativity of protein [1]. Consequently, under physiologically relevant conditions, these variants can transiently populate a partially unfolded state in which the beta-domain and the C-helix are cooperatively unfolded while the rest of the protein remains native like [1]. The formation of intermolecular interactions between the regions that are unfolded in this intermediate state is likely to be a fundamental trigger of the aggregation process that ultimately leads to the formation and deposition of fibrils in tissues. The binding of three variable domain of camelid antibodies – also named nanobodies - (cAb-HuL 6 [2], cAb-HuL 5 and cAb-HuL 22 [3]) raised against the wild type human lysozyme inhibit in vitro the formation of amyloid fibrils by the lysozyme variants. These three nanobodies bind on different regions of lysozyme and act as Amyloid fibrils inhibitor through different mechanisms. On one hand, cAb-HuL 6 and cAb-HuL 22 stabilize the native state of the lysozyme variants thus restoring the global cooperativity characteristic of the wild-type protein. On the other, cAb-HuL 5 probably acts by binding soluble prefibrillar aggregates. In the present work, sixteen other nanobodies specific of human lysozyme have been generated. Competition experiments have shown that they bind to five non overlapping epitopes. The effects of the binding of these nanobodies on the stability of the D67H variant of human lysozyme and on its aggregation into amyloid fibrils will be discussed. [less ▲]

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See detailDesign, implementation, and tests of the architecture of the radiocommunication system of the OUFTI-1 CubeSat
Marchal, Nicolas; Broun, Valéry; Denis, Amandine ULg et al

Poster (2010)

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See detailCA1838, A NANOBODY INHIBITING THE METALLO-β-LACTAMASE VIM-4.
Sohier, Jean ULg; Laurent, Clémentine ULg; Pardon, Els et al

Poster (2010)

Detailed reference viewed: 20 (17 ULg)
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See detailPathogenicity of Pseudomonas cichorii isolates causing midrib rot on greenhouse butterhead lettuce
Pauwelyn, E.; Braekevelt, S.; Ongena, Marc ULg et al

Poster (2010)

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See detailVapor phase doping for ultra shallow junction formation in advanced Si CMOS devices
Shimizu, Yasuo; Nguyen, Ngoc Duy ULg; Jiang, Sijia et al

Poster (2010)

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See detailThermodynamic and Kinetic Contributions to Stability Adaptation in a Psychrophilic Alpha-amylase
Cipolla, Alexandre; D'Amico, Salvino; Feller, Georges ULg

Poster (2010)

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See detailMassive stars, a lifetime of influence
Nazé, Yaël ULg

Poster (2010)

Detailed reference viewed: 6 (4 ULg)
See detailCamelid single-domain antibody fragments as structural probes to study the mechanism of human lysozyme fibrils formation
Dumont, Janice ULg; Pardon, Els; Menzer, Linda ULg et al

Poster (2010)

Six variants of human lysozyme (single-point mutations I56T, F57I, W64R, D67H and double mutations F57I/T70N, W112R/T70N) are associated with a hereditary non-neuropathic systemic amyloidosis. These ... [more ▼]

Six variants of human lysozyme (single-point mutations I56T, F57I, W64R, D67H and double mutations F57I/T70N, W112R/T70N) are associated with a hereditary non-neuropathic systemic amyloidosis. These proteins form extracellular amyloid fibrils that deposit in a wide range of tissues and organs such as liver, spleen and kidneys where they cause damages [1]. It was shown that the D67H and I56T mutations cause a loss in stability and more particularly a loss of global cooperativity of protein [1]. Consequently, under physiologically relevant conditions, these variants can transiently populate a partially unfolded state in which the beta-domain and the C-helix are cooperatively unfolded while the rest of the protein remains native like [1]. The formation of intermolecular interactions between the regions that are unfolded in this intermediate state is likely to be a fundamental trigger of the aggregation process that ultimately leads to the formation and deposition of fibrils in tissues. The binding of three variable domain of camelid antibodies – also named nanobodies - (cAb-HuL 6 [2], cAb-HuL 5 and cAb-HuL 22 [3]) raised against the wild type human lysozyme inhibit in vitro the formation of amyloid fibrils by the lysozyme variants. These three nanobodies bind on different regions of lysozyme and act as amyloid fibrils inhibitor through different mechanisms. On one hand, cAb-HuL 6 and cAb-HuL 22 stabilize the native state of the lysozyme variants thus restoring the global cooperativity characteristic of the wild-type protein. On the other, cAb-HuL 5 probably acts by binding soluble prefibrillar aggregates. In the present work, sixteen other nanobodies specific of human lysozyme have been generated. Competition experiments have shown that they bind to five non overlapping epitopes. The effects of the binding of these nanobodies on the stability of the D67H variant of human lysozyme and on its aggregation into amyloid fibrils will be discussed. References [1] Dumoulin et al, (2006) Acc. Chem. Res, 39, 603-610. [2] Dumoulin et al, (2003) Nature, 424, 783-788. [3] Chan et al. (2008) Biochemistry, 47,11041-11054. [less ▲]

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