References of "Brasseur, Catherine"
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See detailMeasurement of Dechloranes and PBDEs in European Human Serum
Brasseur, Catherine ULg; Focant, Jean-François ULg

Scientific conference (2013, May)

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See detailForensic Cadaveric Decomposition Profiling by GC×GC-TOFMS Analysis of VOCs
Focant, Jean-François ULg; Stefanuto, Pierre-Hugues ULg; Brasseur, Catherine ULg et al

in Chemical Bulletin of Kazakh National University (2013), 72(4), 177-186

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See detailLevels of Dechloranes and PBDEs in Serum from Central European Population
Brasseur, Catherine ULg; Focant, Jean-François ULg

in Organohalogen Compounds (2013), 75

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See detailSymbiont Diversity in Reticulitermes santonensis (Isoptera: Rhinotermitidae): Investigation Strategy Through Proteomics.
Bauwens, Julien ULg; Millet, Catherine ULg; Tarayre, Cédric ULg et al

in Environmental entomology (2013), 42(5), 882-7

The complex microbial community living in the hindgut of lower termites includes prokaryotes, flagellates, yeasts, and filamentous fungi. Many microorganisms are found in the termite gut, but only a few ... [more ▼]

The complex microbial community living in the hindgut of lower termites includes prokaryotes, flagellates, yeasts, and filamentous fungi. Many microorganisms are found in the termite gut, but only a few are thought to be involved in symbiotic association to participate in cellulose digestion. Proteomics provides analyses from both taxonomical and functional perspectives. We aimed to identify symbiont diversity in the gut of Reticulitermes santonensis (Feytaud), via complementary electrospray ionization associated to ion trap tandem mass spectrometry (LC-MS/MS) and two-dimensional gel electrophoresis associated to matrix-assisted laser desorption-ionization-time-of-flight mass spectrometry analysis. One specific challenge to the study of lower termites is the relatively few data available on abundant symbiotic flagellates. Analysis based on LC-MS/MS revealed few protein families showing assignments to eukaryotes and the taxonomic origin of highly represented actins could not be established. Tubulins proved to be the most suitable protein family with which to identify flagellate populations from hindgut samples using LC-MS/MS, compared with other protein families, although this method targeted few prokaryotes in our assay. Similarly, two-dimensional gel electrophoresis associated to matrix-assisted laser desorption-ionization-time-of-flight mass spectrometry did not succeed in identifying flagellate populations, but did permit the identification of most of the prokaryotic components of the symbiotic system. Finally, fungi and yeasts were identified by both methods. Owing to the lack of sequenced genes in flagellates, targeting tubulins for LC-MS/MS could allow fingerprints of flagellate populations to be established. Experimental and technical improvements might increase the efficiency of identification of prokaryotic populations in the near future, based on metaproteomic development. [less ▲]

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See detailEffects of a sublethal pesticide exposure on locomotor behavior: A video-tracking analysis in larval amphibians
Denoël, Mathieu ULg; Libon, Sylvie; Kestemont, Patrick et al

in Chemosphere (2013), 90(3), 945-951

Organochlorine pesticides such as endosulfan have been shown to have both lethal and sublethal effects on amphibians. In this context, behavioral endpoints have proved their usefulness in evidencing ... [more ▼]

Organochlorine pesticides such as endosulfan have been shown to have both lethal and sublethal effects on amphibians. In this context, behavioral endpoints have proved their usefulness in evidencing impacts of such chemicals at environmental concentrations that do not necessarily cause mortality. The recent development of video-tracking technologies now offers the possibility of accurately quantifying locomotor behaviors. However, these techniques have not yet been applied to evaluating the toxicity of pesticides in amphibians. We therefore aimed at determining the potential toxicity of endosulfan on endpoints associated with locomotion after short-term environmental endosulfan exposure in Rana temporaria tadpoles and at using these data as warning systems for survival alterations after a longer exposure. To this end, we analyzed video-tracks of 64 tadpoles (two pesticide treatments: 5 and 50 μg L−1, one control and one solvent-control) with Ethovision XT 7 software. The highest endosulfan concentration had a significant effect on all four behavioral endpoints. Contaminated tadpoles traveled shorter distances, swam less often, at a lower mean speed, and occupied a less peripherical position than control tadpoles. The lowest endosulfan concentration had similar but lower effects, and did not affect mean speed during swimming. Survival was reduced only after a long-term exposure to endosulfan and was associated with short-term behavioral dysfunctions. These results show that endosulfan strongly affects the behavioral repertory of amphibian tadpoles, but in different ways depending on concentration, thus suggesting that the pesticide has complex modes of action. Given the importance of locomotion and space use in tadpole success in their aquatic environment, these results confirm the toxic action of endosulfan. By highlighting effects before mortality markers, video-tracking systems also show their potential as sentinels of sublethal effects of pesticides. [less ▲]

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See detailInfluence of lignin in Reticulitermes santonensis: symbiotic interations investigated through proteomics
Bauwens, Julien ULg; Tarayre, Cédric ULg; Brasseur, Catherine ULg et al

in Symbiosis (2013)

The gut of lower termites is populated by numerous microbial species belonging to prokaryotes, fungi, yeasts and protists. These micro-organisms are organized in a complex symbiotic system, interacting ... [more ▼]

The gut of lower termites is populated by numerous microbial species belonging to prokaryotes, fungi, yeasts and protists. These micro-organisms are organized in a complex symbiotic system, interacting together and with the insect host. Their likely ability to degrade ligno-cellulosic compounds could lead to improvements in second generation biofuels production. Lignin elimination represents a critical point as this polymer significantly interferes with industrial process of cellulose. Although host produces its own lignin-degrading enzymes, some symbionts may participate in digestion of lignin and its degradation products in termite gut. Here, we compared gut proteomes from R. santonensis after rearing on artificial diets composed of cellulose with and without lignin. The effect of lignin in artificial diets on different parts of the digestive tract was compared through liquid chromatography associated with tandem mass spectrometry (LC-MS/MS) experiments. Enzymatic assays were performed to characterize activities present in R. santonensis digestive tract after feeding on artificial diets. Microscopic observations of microbial communities provided some information on population balances after feeding experiment. [less ▲]

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See detailUtilisation des termites comme source de microorganismes dans la filière de production du bioéthanol de seconde génération
Tarayre, Cédric ULg; Bauwens, Julien ULg; Brasseur, Catherine ULg et al

Poster (2012, November 14)

Les termites abritent une microflore symbiotique qui intervient dans la dégradation des fibres constitutives du bois, synthétisant des enzymes capables d’hydrolyser ses composants. Les sucres ... [more ▼]

Les termites abritent une microflore symbiotique qui intervient dans la dégradation des fibres constitutives du bois, synthétisant des enzymes capables d’hydrolyser ses composants. Les sucres fermentescibles libérés suite à cette hydrolyse sont utilisables dans le cadre de la production du bioéthanol de seconde génération. [less ▲]

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See detailTermites artificially-fed on unusual diet and resulting enzymatic switches
Bauwens, Julien ULg; Tarayre, Cédric ULg; Matteotti, Christel et al

Poster (2012, August)

Wood-feeding termites as Reticulitermes santonensis generally feed on cellulose, hemicelluloses and lignin. However, these opportunistic insects are also able to degrade other carbohydrates, such as ... [more ▼]

Wood-feeding termites as Reticulitermes santonensis generally feed on cellulose, hemicelluloses and lignin. However, these opportunistic insects are also able to degrade other carbohydrates, such as starch. The production of putative endogenous α - amylase has been previously shown in R. flavipes, as the disappearance of the major symbiotic flagellates from the hindgut. Here, we compared enzymatic activities (CMCase, MCCase, xylanase, amylase, α- and β-glucosidase) between different fractions of the digestive tract of starch-, cellulose-, and wood-fed termites. Main compounds of the artificial diets, namely starch or MCC, resulted in differential enzymatic activity. Even the substitution of wood by artificial diets itself seemed to induce changes in enzymatic activities, regardless of the main substrate in the diet, as we observed strong midgut α-glucosidase activity only for artificially-fed termites. Preliminary assays to isolate and characterize enzymes were performed using proteomic methods. [less ▲]

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See detailMeasurement of human levels of Dechlorane 602 by CZC-NCI-HRTOFMS
Brasseur, Catherine ULg; PIRARD, Catherine ULg; L'Homme, Benjamin ULg et al

in Organohalogen Compounds (2012, August), 74

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See detailGCxGC-TOFMS for Bioanalytical Applications
Brasseur, Catherine ULg; L'Homme, Benjamin ULg; Stefanuto, Pierre-Hugues ULg et al

Scientific conference (2012, August)

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See detailSelection and cultivation of hydrolytic microorganisms extracted from the digestive tract of the termite Reticulitermes santonensis (3DV.1.55)
Tarayre, Cédric ULg; Bauwens, Julien ULg; Matteotti, Christel ULg et al

Poster (2012, June 21)

Biofuel production can be based on the use of fermentable substrates issued from the hydrolysis of lignocellulosic biomass stemming from agricultural residues and by-products. However, such substrates are ... [more ▼]

Biofuel production can be based on the use of fermentable substrates issued from the hydrolysis of lignocellulosic biomass stemming from agricultural residues and by-products. However, such substrates are not easy to degrade. Enzymes (cellulases, xylanases, etc.) can be used for this purpose and pre-treatments can increase their action by providing more available extremities. The digestive tract of the termite Reticulitermes santonensis contains various microorganisms (bacteria, molds, protists) able to degrade the wood components. These microorganisms act as consortia, leading to a better hydrolysis than in the cow rumen. Our purpose is the isolation of microorganisms from termite guts in order to evaluate their potential for hydrolysis of lignocellulosic materials. This approach led us to isolate and to study a bacteria (Bacillus sp.) displaying a xylanase activity, a mold (Aspergillus sp.) displaying a cellulase activity and a chrysophyte (protist) displaying an amylase activity. [less ▲]

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See detailEnhanced Characterization of the Smell of Death by Comprehensive Two-Dimensional Gas Chromatography-Time-of-Flight Mass Spectrometry (GCxGC-TOFMS)
Dekeirsschieter, Jessica ULg; Stefanuto, Pierre-Hugues ULg; Brasseur, Catherine ULg et al

in PLoS ONE (2012), 7(6), 39005

Soon after death, the decay process of mammalian soft tissues begins and leads to the release of cadaveric volatile compounds in the surrounding environment. The study of postmortem decomposition products ... [more ▼]

Soon after death, the decay process of mammalian soft tissues begins and leads to the release of cadaveric volatile compounds in the surrounding environment. The study of postmortem decomposition products is an emerging field of study in forensic science. However, a better knowledge of the smell of death and its volatile constituents may have many applications in forensic sciences. Domestic pigs are the most widely used human body analogues in forensic experiments, mainly due to ethical restrictions. Indeed, decomposition trials on human corpses are restricted in many countries worldwide. This article reports on the use of comprehensive two-dimensional gas chromatography coupled with time-offlight mass spectrometry (GCxGC-TOFMS) for thanatochemistry applications. A total of 832 VOCs released by a decaying pig carcass in terrestrial ecosystem, i.e. a forest biotope, were identified by GCxGC-TOFMS. These postmortem compounds belong to many kinds of chemical class, mainly oxygen compounds (alcohols, acids, ketones, aldehydes, esters), sulfur and nitrogen compounds, aromatic compounds such as phenolic molecules and hydrocarbons. The use of GCxGC-TOFMS in study of postmortem volatile compounds instead of conventional GC-MS was successful. [less ▲]

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