References of "Eppe, Gauthier"
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See detailDietary early-life exposure to contaminated eels does not impair spatial cognitive performances in adult offspring mice as assessed in the Y-maze and the Morris water maze
Dridi, ImenI; Leroy, Delphine; Guignard, Cedric et al

in Nutrition Research (in press)

Many environmental contaminants are introduced via the diet and may act as neurotoxins and endocrine disrupters, especially influencing growing organisms in early life. The purpose of this study was to ... [more ▼]

Many environmental contaminants are introduced via the diet and may act as neurotoxins and endocrine disrupters, especially influencing growing organisms in early life. The purpose of this study was to examine whether dietary exposure of dams to fish naturally contaminated with xenobiotics, especially with polychlorinated biphenyls (PCBs) and heavy metals (e.g. mercury and lead), resulted in cognitive function deficits in adult offspring mice. Daily, four groups of dams (n = 10/group) ingested standard diet plus paste with/without eels, during gestation and lactation, from gestational day (GD) six until post natal day (PND) 21 (weaning). Dams orally ingested a standardized amount of eel (0.8 mgkg-1 d-1) containing the six non-dioxin-like (NDL) PCBs (σ6 NDL-PCBs: 28, 52, 101, 138, 153, and 180) at 0, 85, 216, and 400 ngkg-1 d-1. Results showed that early-life exposure to contaminated eels did not (compared to non-exposed controls) impair immediate working memory in the Y-maze in the offspring assessed at PND 38. Furthermore, it did not significantly impact spatial learning and retention memory as measured in the Morris water maze in adult offspring mice (PND 120-123). Our results suggest that perinatal exposure to contaminated eels does not affect spatial cognitive performances, as assessed by the Y-maze and Morris water maze at adult age. Adverse effects of xenobiotics reported earlier might be camouflaged by beneficial eel constituents, such as n-3 fatty acids. However, additional studies are needed to differentiate between potential positive and negative effects following consumption of food items both rich in nutrients and contaminants. © 2014 Elsevier Inc. [less ▲]

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See detailContribution of ion mobility for structural analysis and analytical chemistry: Use of selective IMS shift reagents (SSR)
Kune, Christopher ULg; Far, Johann ULg; Delvaux, Cédric ULg et al

Poster (2014, June 19)

Ion mobility is a gas phase separation technique based on the Collisional Cross Section (CCS) of ions. It discriminates isobaric and isomeric ions provided their CCS difference is larger than the ... [more ▼]

Ion mobility is a gas phase separation technique based on the Collisional Cross Section (CCS) of ions. It discriminates isobaric and isomeric ions provided their CCS difference is larger than the instrumental resolution. This work proposes a new method to overcome this limitation while providing additional structural information. A Selective Shift Reagent (SSR) is a ligand specifically modifying the CCS of ions. Indeed specific non-covalent complexes can be form with a suitable SSR to reach the required selectivity and the CCS induced shift. A CID dissociation of the complex may be used after IMS separation to produce specific MS/MS spectra of the targeted analyte. This concept paves the way for new analytical strategies by ion mobility based on non-covalent complex formation. [less ▲]

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See detailInnovative analytical strategies for small molecules analysis by ion-mobility mass spectrometry
Eppe, Gauthier ULg; Goscinny, Séverine; Far, Johann ULg et al

Conference (2014, January)

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See detailMatrix ‐ assisted laser desorption/ionization mass spectrometry and Raman spectroscopy: An interesting complementary approach for lipid detection in biological tissues
Jadoul, Laure ULg; Malherbe, Cédric ULg; calligaris, David et al

in European Journal of Lipid Science and Technology [=EJLST] (2014)

Recently, matrix‐assisted laser desorption/ionization mass spectrometry imaging (MALDI MSI) has emerged as a powerful technique to study the distribution of lipids. However, quantification still remains a ... [more ▼]

Recently, matrix‐assisted laser desorption/ionization mass spectrometry imaging (MALDI MSI) has emerged as a powerful technique to study the distribution of lipids. However, quantification still remains a challenge because the MALDI signal is strongly affected by ion suppression effects. On the contrary, Raman spectroscopy is recognized as a non‐destructive analysis method and spectral images can also be acquired. The combination of these two techniques was applied for lipids detection in tissue sections. In MALDI, two lipids families (glycerophosphocholine, PC; gycerophosphoethanolamine, PE), three MALDI matrices (1,5‐diaminonapthalene, 1,5‐DAN; 2,5‐dihydroxybenzoic acid, 2,5‐DHB; a‐4‐hydroxicinammic acid, CHCA), and various mixtures of lipids were investigated. The nature of the lipid, as well as the nature of the matrix and the composition of the sample influences the signal of a given lipid. In Raman, despite a strong overlap with the spectrum of the native tissue, an intensity profile constructed along the diameter of the section clearly shows that the signature of one given lipid (a glycerophosphocholine) can be detected on a doped biological sample. [less ▲]

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See detailDetermination of the Al2O3 content in NaF-AlF 3-CaF2-Al2O3 melts at 950 °c by raman spectroscopy
Malherbe, Cédric ULg; Eppe, Gauthier ULg; Gilbert, Bernard ULg

in Analytical Chemistry (2014)

Thein situ control of the chemical composition of industrial aluminum smelter is a challenge mainly for physicochemical reasons: high temperature, high surrounding electromagnetic field, and the highly ... [more ▼]

Thein situ control of the chemical composition of industrial aluminum smelter is a challenge mainly for physicochemical reasons: high temperature, high surrounding electromagnetic field, and the highly corrosive molten salt electrolyte to deal with. In previous works, we proposed that Raman spectroscopy is a method of choice that could be adapted to real smelters. The laboratory study presented here relies on reproducible Raman spectra recorded on molten mixtures whose compositions are identical to those used during the production of aluminum. A normalization procedure for the Raman spectra is proposed based on the equilibria taking place in the bath. In addition, we discuss two quantitative models to determine the alumina content from the Raman spectra of the molten NaF−AlF3−CaF2−Al2O3 electrolytes. Univariate and multivariate approaches are applied to determine both theCOx (alumina content) and the CR (NaF/AlF3 molar ratio) by Raman spectroscopy without referring to an additional internal reference of intensity. The procedure was successfully tested and validated on industrial samples. [less ▲]

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See detailLack of isocitrate lyase in Chlamydomonas leads to changes in carbon metabolism and in the response to oxidative stress under mixotrophic growth.
Plancke, Charlotte; Vigeolas, Hélène ULg; Hohner, Ricarda et al

in The Plant journal : for cell and molecular biology (2014), 77(3), 404-417

Isocitrate lyase is a key enzyme of the glyoxylate cycle. This cycle plays an essential role in cell growth on acetate, and is important for gluconeogenesis as it bypasses the two oxidative steps of the ... [more ▼]

Isocitrate lyase is a key enzyme of the glyoxylate cycle. This cycle plays an essential role in cell growth on acetate, and is important for gluconeogenesis as it bypasses the two oxidative steps of the tricarboxylic acid (TCA) cycle in which CO2 is evolved. In this paper, a null icl mutant of the green microalga Chlamydomonas reinhardtii is described. Our data show that isocitrate lyase is required for growth in darkness on acetate (heterotrophic conditions), as well as for efficient growth in the light when acetate is supplied (mixotrophic conditions). Under these latter conditions, reduced acetate assimilation and concomitant reduced respiration occur, and biomass composition analysis reveals an increase in total fatty acid content, including neutral lipids and free fatty acids. Quantitative proteomic analysis by 14 N/15 N labelling was performed, and more than 1600 proteins were identified. These analyses reveal a strong decrease in the amounts of enzymes of the glyoxylate cycle and gluconeogenesis in parallel with a shift of the TCA cycle towards amino acid synthesis, accompanied by an increase in free amino acids. The decrease of the glyoxylate cycle and gluconeogenesis, as well as the decrease in enzymes involved in beta-oxidation of fatty acids in the icl mutant are probably major factors that contribute to remodelling of lipids in the icl mutant. These modifications are probably responsible for the elevation of the response to oxidative stress, with significantly augmented levels and activities of superoxide dismutase and ascorbate peroxidase, and increased resistance to paraquat. [less ▲]

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See detailDevelopment of a Standard Reference Material for Metabolomics Research
Phinney, K; Ballihaut, G; Bedner, M et al

in Analytical Chemistry (2013), 85(24), 11732-11738

The National Institute of Standards and Technology (NIST), in collaboration with the National Institutes of Health (NIH), has developed a Standard Reference Material (SRM) to support technology ... [more ▼]

The National Institute of Standards and Technology (NIST), in collaboration with the National Institutes of Health (NIH), has developed a Standard Reference Material (SRM) to support technology development in metabolomics research. SRM 1950 Metabolites in Human Plasma is intended to have metabolite concentrations that are representative of those found in adult human plasma. The plasma used in the preparation of SRM 1950 was collected from both male and female donors, and donor ethnicity targets were selected based upon the ethnic makeup of the U.S. population. Metabolomics research is diverse in terms of both instrumentation and scientific goals. This SRM was designed to apply broadly to the field, not towards specific applications. Therefore, concentrations of approximately 100 analytes, including amino acids, fatty acids, trace elements, vitamins, hormones, selenoproteins, clinical markers, and perfluorinated compounds (PFCs), were determined. Value assignment measurements were performed by NIST and the Centers for Disease Control and Prevention (CDC). SRM 1950 is the first reference material developed specifically for metabolomics research. [less ▲]

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See detailInnovative analytical strategy using ion-mobility shifting additive for isobaric selenium compound identification in selenomethionine standards by IMS
Kune, Christopher ULg; Far, Johann ULg; Eppe, Gauthier ULg et al

Conference (2013, July 09)

Selenium (Se) is a trace element which is both essential and toxic depending on its concentration and its chemical form. Selenomethionine (SeMet) is one of the widely used selenium standard during ... [more ▼]

Selenium (Se) is a trace element which is both essential and toxic depending on its concentration and its chemical form. Selenomethionine (SeMet) is one of the widely used selenium standard during Selenium speciation studies. This work was focused on the elaboration of an analytical strategy for the detection and the structural elucidation of an isobaric Se interference, which is found in standard solutions of SeMet by high resolution mass spectrometry (Rm/Δm > 20.000). The structural elucidation of these compounds requires the isolation of the respective parent ion. Nevertheless, the mass difference between SeMet and its interference is less than 0.02Da which is well below the window selection of conventional techniques in mass spectrometry (Quadripole, ion trap). The empirical formula and double bound equivalent (DBE) of these ions suggest different tridimensional structures which lead to a discrimination depending on the ion mobility. This separation is observed, both in gaseous and liquid phase, by Ion Mobility Spectrometry (IMS), Capillary Electrophoresis (CE) and Liquid Chromatography (LC) which are hyphenated to mass spectrometry as detector. The separation efficiency of these ions by IMS and CE is improved by using specific shifting agents (18-Crown-6 Ether) selective to only one of these ions. This strategy has successfully separated the two isobaric ions present and leads to the structural elucidation of the isobar contaminant of SeMet. [less ▲]

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See detailInnovative analytical strategy using ion-mobility for structural or functional selenium isomers identification by ion mobility spectrometry
Far, Johann ULg; Kune, Christopher ULg; Lobinski, Ryszard et al

Poster (2013, July)

Selenium (Se) is a trace element which is both essential and toxic depending on its concentration and its chemical form. Se-rich yeast is one of the most popular Se source for supplementation. The ... [more ▼]

Selenium (Se) is a trace element which is both essential and toxic depending on its concentration and its chemical form. Se-rich yeast is one of the most popular Se source for supplementation. The classical method of speciation is related to multidimensional liquid chromatography (LC) hyphenated to mass spectrometry (MS) Recent advances in Se speciation led to greatly improve the Se speciation in these samples but isomers identification and quantification remain challenging. This work focuses on the elaboration of an innovative analytical strategy for the detection and the structural elucidation of isobaric selenium compounds present in Se-rich yeast. A specific complex formation agent acts as a chemical probe for the detection of chemical function. The addition of a complexing agent can improve the discrimination between structural or functional Se isomers using ion mobility techniques as Ion Mobility Spectrometry (IMS) by increasing the molecular weight (i.e. the m/z ratio in MS) and the collision cross section of a target ion after selective complexation. This Ion Mobility orthogonal separation improves the structural elucidation. Crown ethers used as shifting agents can specifically form complexes with primary amines. The addition of crown ether to different low molecular weight fractions obtained by multidimensional LC of a water extract from Se-rich yeast permitted to detect Se isomers and confirmed their structure using IMS. [less ▲]

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See detailDevelopment of an analytical strategy to measure major selenium-containing species in juvenile turtles (Trachemys scripta scripta) by SAX-HPLC-ICP MS
Far, Johann ULg; Dyc, Christelle; Das, Krishna ULg et al

Poster (2013, July)

Sea turtles are exposed to many environmental elements such as selenium (Se). Sea turtles are listed under the Red List of threatened species by the International Union for Conservation of Nature. It is ... [more ▼]

Sea turtles are exposed to many environmental elements such as selenium (Se). Sea turtles are listed under the Red List of threatened species by the International Union for Conservation of Nature. It is thus mandatory to use low-invasive tissue collection (skin, carapace, blood ) for estimating Se exposure in these highly protected turtles. For this purpose, a biological modal Trachemys scripta scripta (or slider turtle) was selected. For two months, juvenile turtles were dietary exposed to Se by spiking the food with Selenomethionine (SeMet) or Methionine as control groups. Individuals were sacrificed after different time of exposure and tissues (skin, liver, muscle, carapace and blood) collected to perform Se speciation and determine some biological endpoints. An analytical strategy was developed to cope with the very low amount of available sample. It is briefly consisting by reduction, alkylation and proteolysis of the entire freeze-dried tissues followed by sample clean-up using ultra-filtration membrane. Then anion exchange HPLC using salt and pH gradient was developed to prevent the introduction of organic solvents, which cause severe fooling of ICP MS and avoid ultra-trace analyses of sea water in routine analysis. This method successfully achieved the detection and quantification at ppm level of expected species (i.e SeMet, selenocysteine, inorganic Se) and also unknown species but their relative amounts were time and tissues dependent. [less ▲]

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See detailDevelopment of a quantitative approach to measure phospholipids in dried drops by Raman spectroscopy
Malherbe, Cédric ULg; Jadoul, Laure ULg; Gilbert, Bernard ULg et al

Poster (2013, May 24)

Phospholipids, PL, such as the phosphatidylcholine PC(18:0/18:1), play a role in the structure of living cells and are suspected to be part of the development of some diseases, for example cancers. Mass ... [more ▼]

Phospholipids, PL, such as the phosphatidylcholine PC(18:0/18:1), play a role in the structure of living cells and are suspected to be part of the development of some diseases, for example cancers. Mass spectrometry enables the structural analysis of PL in complex biological media but imaging mass spectrometry by MALDI-MS is rather limited for quantification purposes. Complementarily, Raman spectroscopy as a non invasive and non destructive method is a potential candidate to quantify and visualise the spatial distribution of the PL by molecular imaging. Unfortunately, the lack of specific chemical function in PL, compared to others biomolecules, limits the use of Raman spectroscopy in the identification process of those PL in complex biological samples. The results presented here belong to a first study of the application of the Raman analyses on dried residues of PL and mice brain tissue performed in the lab. [less ▲]

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See detailPreliminary assessment of the risk linked to furan ingestion by babies consuming only ready-to-eat food
Scholl, Georges ULg; Humblet, Marie-France ULg; Scippo, Marie-Louise ULg et al

in Food Additives & Contaminants. Part A. Chemistry, Analysis, Control, Exposure & Risk Assessment (2013), 30(4), 654-659

The risk linked to furan ingestion has been assessed in previous papers for Belgian adults and children (Scholl et al., 2012b; Scholl et al., 2012c). The present paper focuses on infants consuming only ... [more ▼]

The risk linked to furan ingestion has been assessed in previous papers for Belgian adults and children (Scholl et al., 2012b; Scholl et al., 2012c). The present paper focuses on infants consuming only ready-to-eat baby food. As there is no Belgian baby dietary database, the furan exposure assessment was carried out by using Italian infant consumption database and Belgian contamination data. The estimated daily intake (EDI) was calculated according to a deterministic methodology. It involved 42 commercially available ready-to-eat baby food and 36 baby consumption records. The mean EDI was 1,460 ng * (kgb.w.*day)-1 which is 3.8 times higher than the 381 ng * (kgb.w.*day)-1 reported for Belgian adults, and 3.5 times higher than the 419 ng * (kgb.w. * day)-1 measured for Belgian children. To assess and characterize the risk for babies exposure the Margin of Exposure (MoE) was calculated. It highlighted that 74% of infants have a MoE below 1,000, with a minimum of 140. However, these are only preliminary results as they were calculated from a very small dataset and the infant cytochrome P450 activity is significantly different compared to the adult. Therefore, the risk linked to furan ingestion by babies should be assessed in a different manner. To this end, additional data regarding a baby diet as well as a better understanding of furan toxicity for babies are needed to characterize more accurately the risk for infants. [less ▲]

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See detailRelationships between in vitro lymphoproliferative responses and levels of contaminants in blood of free-ranging adult harbour seals (Phoca vitulina) from the North Sea
Dupont, Aurélie ULg; Siebert, Ursula; Covaci, Adrian et al

in Aquatic Toxicology (2013), 142-143

tIn vitro culture of peripheral blood leucocytes (PBLs) is currently used in toxicological studies of marinemammals. However, blood cells of wild individuals are exposed in vivo to environmental ... [more ▼]

tIn vitro culture of peripheral blood leucocytes (PBLs) is currently used in toxicological studies of marinemammals. However, blood cells of wild individuals are exposed in vivo to environmental contaminantsbefore being isolated and exposed to contaminants in vitro. The aim of this study was to highlightpotential relationships between blood contaminant levels and in vitro peripheral blood lymphocyteproliferation in free-ranging adult harbour seals (Phoca vitulina) from the North Sea. Blood samplesof 18 individuals were analyzed for trace elements (Fe, Zn, Se, Cu, Hg, Pb, Cd) and persistent organiccontaminants and metabolites ( PCBs, HO-PCBs, PBDEs, 2-MeO-BDE68 and 6-MeO-BDE47, DDXs,hexachlorobenzene, oxychlordane, trans-nonachlor, pentachlorophenol and tribromoanisole). The samesamples were used to determine the haematology profiles, cell numbers and viability, as well as thein vitro ConA-induced lymphocyte proliferation expressed as a stimulation index (SI). Correlation tests(Bravais-Pearson) and Principal Component Analysis with multiple regression revealed no statisticallysignificant relationship between the lymphocyte SI and the contaminants studied. However, the numberof lymphocytes per millilitre of whole blood appeared to be negatively correlated to pentachlorophenol(r = −0.63, p = 0.005). In adult harbour seals, the interindividual variations of in vitro lymphocyte pro-liferation did not appear to be directly linked to pollutant levels present in the blood, and it is likelythat other factors such as age, life history, or physiological parameters have an influence. In a generalmanner, experiments with in vitro immune cell cultures of wild marine mammals should be designed soas to minimize confounding factors in which case they remain a valuable tool to study pollutant effectsin vitro. [less ▲]

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See detailHigh accumulation of PCDD, PCDF, and PCB congeners in marine mammals from Brazil: a serious PCB problem
Dorneles, Paulo R; Sanz, Paloma; Eppe, Gauthier ULg et al

in Science of the Total Environment (2013), 463-464

Blubber samples from three delphinid species (false killer whale, Guiana and rough-toothed dolphin), as well as liver samples from franciscana dolphins were analyzed for dioxins and related compounds ... [more ▼]

Blubber samples from three delphinid species (false killer whale, Guiana and rough-toothed dolphin), as well as liver samples from franciscana dolphins were analyzed for dioxins and related compounds (DRCs). Samples were collected from 35 cetaceans stranded or incidentally captured in a highly industrialized and urbanized area (Southeast and Southern Brazilian regions). Dioxin-like PCBs accounted for over 83% of the total TEQ for all cetaceans. Non-ortho coplanar PCBs, for franciscanas (82%), and mono-ortho PCBs (up to 80%), for delphinids, constituted the groups of highest contribution to total TEQ. Regarding franciscana dolphins, significant negative correlations were found between total length (TL) and three variables, ΣTEQ-DRCs, ΣTEQ-PCDF and ΣTEQ non-ortho PCB. An increasing efficiency of the detoxifying activity with the growth of the animal may be a plausible explanation for these findings. This hypothesis is reinforced by the significant negative correlation found between TL and PCB126/PCB169 concentration ratio. DRC concentrations (ng/g lipids) varied from 36 to 3006, for franciscana dolphins, as well as from 356 to 30776, for delphinids. The sum of dioxin-like and indicator PCBs varied from 34662 to 279407 ng/g lipids, for Guiana dolphins from Rio de Janeiro state, which are among the highest PCB concentrations ever reported for cetaceans. The high concentrations found in our study raise concern not only on the conservation of Brazilian coastal cetaceans, but also on the possibility of human health problem due to consumption of fish from Brazilian estuaries. [less ▲]

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See detailScreening and confirmatory methods for the detection of dioxins and polychlorinated biphenyls (PCB) in foods
Focant, Jean-François ULg; Eppe, Gauthier ULg

in Rose, Martin; Fernandes, Alwyn (Eds.) Persistent organic pollutants and toxic metals in foods (2013)

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