References of "De Pauw, Edwin"
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See detailDépérissement de nos abeilles?
Nguyen, Bach Kim ULg; Widart, Joëlle ULg; De Pauw, Edwin ULg et al

Article for general public (2007)

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See detailMercury in the blood of free ranging pinnipeds: levels, sources of variation, toxicocinetic and potential impact using an in vitro model
Das, Krishna ULg; De Pauw-Gillet, Marie-Claire ULg; Habran, Sarah ULg et al

Conference (2007)

Despite 30 years of international regulations, Hg levels in marine mammals have not decreased. Various environmental models even suggest a rise of mercury in the biota during the next decades, linked to ... [more ▼]

Despite 30 years of international regulations, Hg levels in marine mammals have not decreased. Various environmental models even suggest a rise of mercury in the biota during the next decades, linked to climate change. The objective of this study is (1) to assess Hg levels in blood samples of free-ranging pinnipeds, (2) to understand level variation during different periods of life (gestation, lactation, fasting) and potential impact on lymphocytes using a preliminary in vitro model (peripheral blood mononuclear cells, PBMC). Blood samples were collected from harbour seals (Phoca vitulina n= 22) from the North Sea and from elephant seals from the Californian coast (Mirounga angustirostris 12 females and 12 pups). Harbour seal PBMC were isolated, set in medium culture and contaminated with methyl-Hg (1 µM). Biological tests and proteomic assay were realized on control and contaminated PBMC. Hg levels were from the same order of magnitude for the two species despite two different lifestyles and habitats: from 40 to 590 ng.g-1 fw in harbour seal and from 63 to 919 ng.g-1 fw in elephant seal. Hg concentrations in the blood depend upon several factors such as body weight, fasting and lactation duration for mothers and pups. After 21 days of lactation, female elephant seals doubled their blood Hg levels (from 308 to 593 ng.g-1fw) while a decrease is observed for pups. This increase is linked to mobilization from blubber and muscle during fasting associated to lactation. Cell model revealed an in vitro effect of Hg even at low concentration (1µM). Number of PBMC, viability, metabolic activity, DNA and RNA synthesis were reduced in vitro suggesting deleterious effects of Hg in concentrations encountered in free-ranging pinnipeds. Knowing that Hg methylation in the ocean is linked to temperature, one can wonder on Hg levels (and effects) in pinnipeds during the next decades. [less ▲]

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See detailAdvances in immunoproteomics for serological characterization of microbial antigens
Falisse-Poirier, Nandini; Ruelle, Virginie ULg; Elmoualij, Benaïssa ULg et al

in Journal of Microbiological Methods (2006), 67(3), 593-596

We propose a multi-dimensional strategy, associating immunodetection to a protein fractionating two-dimensional liquid chromatography tool, for serological characterization of microbial antigens. The ... [more ▼]

We propose a multi-dimensional strategy, associating immunodetection to a protein fractionating two-dimensional liquid chromatography tool, for serological characterization of microbial antigens. The originality of such immunoproteomic approaches resides in their application in large-scale studies for rapid serotyping of micro-organisms, evaluation of immunomes and could be proposed in the development and monitoring of vaccines. (c) 2006 Elsevier B.V. All rights reserved. [less ▲]

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See detailHigh-throughput biomonitoring of dioxins and polychlorinated biphenyls at the sub-picogram level in human serum
Focant, Jean-François ULg; Eppe, Gauthier ULg; Massart, Anne-Cécile ULg et al

in Journal of Chromatography. A (2006), 1130(1), 97-107

We report on the use of a state-of-the-art method for the measurement of selected polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans and polychlorinated biphenyls in human serum specimens ... [more ▼]

We report on the use of a state-of-the-art method for the measurement of selected polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans and polychlorinated biphenyls in human serum specimens. The sample preparation procedure is based on manual small size solid-phase extraction (SPE) followed by automated clean-up and fractionation using multi-sorbent liquid chromatography columns. SPE cartridges and all clean-up columns are disposable. Samples are processed in batches of 20 units, including one blank control (BC) sample and one quality control (QC) sample. The analytical measurement is performed using gas chromatography coupled to isotope dilution high-resolution mass spectrometry. The sample throughput corresponds to one series of 20 samples per day, from sample reception to data quality cross-check and reporting, once the procedure has been started and series of samples keep being produced. Four analysts are required to ensure proper performances of the procedure. The entire procedure has been validated under International Organization for Standardization (ISO) 17025 criteria and further tested over more than 1500 unknown samples during various epidemiological studies. The method is further discussed in terms of reproducibility, efficiency and long-term stability regarding the 35 target analytes. Data related to quality control and limit of quantification (LOQ) calculations are also presented and discussed. (c) 2006 Elsevier B.V. All rights reserved. [less ▲]

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See detailStudy of the effect of exposition of MCF-7/bos cells to 17-ß-estradiol by 2D DIGE
Collodoro, Mike; Dobson, Rowan ULg; Bertrand, Virginie ULg et al

Poster (2006, October)

The aim of this work is to identify biomarkers following exposition to 17ß-estradiol in MCF7/bos (hormonal dependent epithelial mammary cancer) cells. The application is to optimise screening tests that ... [more ▼]

The aim of this work is to identify biomarkers following exposition to 17ß-estradiol in MCF7/bos (hormonal dependent epithelial mammary cancer) cells. The application is to optimise screening tests that will enable the detection (and eventual quantification but not identification) of numerous compounds having an estrogenic activity in a single rapid test. [less ▲]

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See detailFormation de radicaux anions d'ADN par irradiation laser UV et visible et nouveaux canaux de dissociation
Gabelica, Valérie ULg; Tabarin, Thibault; Kinet, Catherine ULg et al

Conference (2006, September 13)

Nous avons exploré récemment les effets de l'irradiation laser dans l'UV ou le visible de polyanions d'ADN dans un piège à ions quadripolaire. Lors de l'irradiation de simple brins ou de double hélices d ... [more ▼]

Nous avons exploré récemment les effets de l'irradiation laser dans l'UV ou le visible de polyanions d'ADN dans un piège à ions quadripolaire. Lors de l'irradiation de simple brins ou de double hélices d'ADN en UV autour de 260 nm, nous avons observé un détachement d'électrons, donnant lieu à des radicaux anions. L'étude de la dépendence de l'efficacité de ce photodétachement d'électrons en fonction de la séquence des brins a révélé que ce phénomène était corrélé au potentiel d'ionisation des bases nucléiques. La guanine est la base la plus facilement oxydée, suivie de l'adénine, de la cytosine et de la thymine. En pratique, plus un brin contient de guanines, plus la formation de radicaux par photodétachement d'électrons est efficace. L'efficacité du photodétachement montre également une dépendence envers l'état de charge du brin (les plus chargés ont une efficacité de détachement plus élevée) et en fonction de la longueur d'onde (avec un maximum d'efficacité autour de 265 nm), montrant que la transition vers un état électronique excité des bases facilite le détachement d'électrons. Plus surprenant encore, des complexes avec des chromophores (ligands du sillon de l'ADN et intercalants) montrent également un photodétachement d'électrons, et ce avec des énergies de photons encore plus basses, correspondant à une absorption dans le visible (i.e. 550 nm pour l'éthidium). Ceci montre que les énergies de liaisons des électrons sont relativement faibles, puisqu'ils peuvent être détachés par des photons de 2.25 eV. Nous avons également étudié la fragmentation des radiaux ainsi produits, par CID dans le piège. Dans le cas des complexes avec les chromophores, les canaux de fragmentation principaux sont des pertes de neutres, y compris des morceaux de ligands. Il est intéressant de constater que les radicaux se fragmentent de la même manière, quel que soit le chromophore irradié qui a donné lieu à sa formation. Cecis suggère que les radicaux se réorganisent rapidement par rapport au temps de l'expérience. Dans le cas de simples brins (12-mères à 20-mères), nous avons constaté une fragmentation plus efficace des radicaux comparés aux ions à couches complètes de même charge. Plus intéressant, les canaux de dissociation sont très particuliers : alors que la CID sur ions à couches complètes donne majoritairement des ions 'w' et 'a-Base', la CID sur les radicaux donne des ions 'w', 'd', 'a radicalaires', et 'z radicalaires'. Il est aisé d'obtenir une bonne couverture de séquence à des énergies de collision faibles. A nouveau, bien que le détachement d'électrons soit initié par les bases guanines, la couverture de séquence est indépendante de la composition, suggérant une redistribution dans les radicaux. L'avantage principal de la fragmentation des radicaux est l'absence de fragments internes (ou 'double fragments'), ce qui facilite le séquencage de novo. De plus, selon notre expérience, la formation des radicaux est plus aisée par irradiation laser que par EDD. [less ▲]

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See detailSuitability of tandem-in-time mass spectrometry for polybrominated diphenylether measurement in fish and shellfish samples: Comparison with high resolution mass spectrometry
PIRARD, Catherine ULg; De Pauw, Edwin ULg; Focant, Jean-François ULg

in Journal of Chromatography. A (2006), 1115(1-2), 125-132

The first part of the present study focused on the development of an alternative automated sample preparation method for the measurement of selected polybrominated diphenyl ethers (PBDEs) in fish and ... [more ▼]

The first part of the present study focused on the development of an alternative automated sample preparation method for the measurement of selected polybrominated diphenyl ethers (PBDEs) in fish and shellfish. A previously developed automated method has been further optimized and simplified to decrease blank levels and cost. Sorbent and solvent quantities have been significantly reduced without altering extract quality. The second part of the study consisted of comparing tandem-in-time quadrupole ion storage mass spectrometry (QISTMS/MS) to high resolution mass spectrometry (HRMS) for the isotope dilution (ID) measurement step after gas chromatography (GC) separation. Both mass spectrometric methods performed similarly in terms of accuracy but better precision was observed for HRMS. Although better sensitivity can be attained with the high resolution sector instrument, method limits of quantification (mLOQs) were very similar for both approaches as they were dependent on the procedural blanks levels. The mLOQ values ranged between 0.04 and 3.56 ng/g fat, depending on the congener. They allowed the unambiguous identification and quantification of all target analytes, except for BDE-183, in most considered fish extracts. An analytical procedure based on rapid automated sample preparation and QISTMS/MS appeared to be suitable for the measurement of PBDEs in fish and shellfish speciment under quality assurance/quality control (QA/QC) criteria. (c) 2006 Elsevier B.V. All rights reserved. [less ▲]

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See detailSaccharomyces cerevisiae mitoproteome plasticity in response to recombinant alternative ubiquinol oxidase
Mathy, Grégory ULg; Navet, Rachel ULg; Gerkens, Pascal et al

in Journal of Proteome Research (2006), 5(2), 339-348

The energy-dissipating alternative oxidase (AOX) from Hansenula anomala, was expressed in Saccharomyces cerevisiae. The recombinant AOX was functional. A comparative analysis by two-dimensional ... [more ▼]

The energy-dissipating alternative oxidase (AOX) from Hansenula anomala, was expressed in Saccharomyces cerevisiae. The recombinant AOX was functional. A comparative analysis by two-dimensional differential in-gel electrophoresis (2D-DIGE) of mitochondrial protein patterns found in wild-type and recombinant AOX strains was performed. 60 proteins exhibiting a significant difference in their abundance were identified. Interestingly, proteins implicated in major metabolic pathways such as Krebs cycle and amino acid biosynthesis were up-regulated. Surprisingly, an up-regulation of the respiratory-chain complex III was associated with a down-regulation of the ATP synthase complex. [less ▲]

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See detailUncoupling protein 1 affects the yeast mitoproteome and oxygen free radical production
Douette, Pierre ULg; Gerkens, Pascal; Navet, Rachel ULg et al

in Free Radical Biology & Medicine (2006), 40(2), 303-315

Uncoupling protein I (UCP1) is a mitochondrial inner membrane protein that dissipates the proton electrochemical gradient built up by the respiratory chain. its activity is stimulated by free fatty acids ... [more ▼]

Uncoupling protein I (UCP1) is a mitochondrial inner membrane protein that dissipates the proton electrochemical gradient built up by the respiratory chain. its activity is stimulated by free fatty acids and inhibited by purine nucleotides. Here we investigated how active and regulated recombinant UCP1 expressed in yeast at similar to 1 and similar to 10 mu g/mg of total mitochondrial proteins induced changes in the mitochondrial proteome and in oxygen free radical production. Using two-dimensional differential in-gel electrophoresis (2D-DIGE), we found that most of the proteins involved in the response to ectopically expressed UCP1 are related to energy metabolism. We also quantified the cellular H2O2 release in the absence or in the presence of UCP1. Our results suggest that UCP1 has a dual influence on free radical generation. On one side, FFA-activated UCP1 was able to decrease the superoxide anion production, demonstrating that a decrease in the generation of reactive oxygen species is an obligatory outcome of UCP1 activity even in a heterologous context. On the other side, an increase in UCP1 content was concomitant with an increase in the basal release of superoxide anion by mitochondria as a side consequence of the overall increase in oxidative metabolism. (c) 2005 Elsevier Inc. All rights reserved. [less ▲]

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See detailStrategy for DR-CALUX dioxin screening in feed under EC regulation
Scippo, Marie-Louise ULg; Rybertt, M. S.; Focant, Jean-François ULg et al

in Organohalogen Compounds (2006), 68

Detailed reference viewed: 42 (7 ULg)