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See detailPOPs in free-ranging pilot whales and sperm whales from the Mediterranean Sea: influence of ecological factors
Pinzone, Marianna ULg; Tasciotti, Aurelie; Ody, Denis et al

Conference (2014, December 13)

The pilot whale Globicephala melas and the sperm whale Physeter macrocephalus are large toothed whales, which permanently inhabit the Northwestern Mediterranean Sea, where they feed mainly on cephalopods ... [more ▼]

The pilot whale Globicephala melas and the sperm whale Physeter macrocephalus are large toothed whales, which permanently inhabit the Northwestern Mediterranean Sea, where they feed mainly on cephalopods. Here they are subjected to numerous anthropogenic threats such as exposure to high levels of contaminants. Selected persistent organic pollutants POPs (29PCBs, 15 organochlorine compounds, 9 PBDEs and 17 PCDD/Fs) were analyzed in blubber biopsies of 49 long-finned pilot whales and 61 sperm whales sampled in NWMS from 2006 to 2013. δ13C, δ15N values and POPs levels were assessed through IR-MS and GC-MS respectively. To assess the toxic potency of the dioxin-like compounds, the TEQ approach was applied. δ15N values were 12.2±1.3‰ for sperm whales and 10.5±0.7‰ for pilot whales, positioning sperm whales at higher trophic levels. δ13C instead was similar and amounted to −17.3±0.4‰ and −17.8±0.3‰ respectively. Pilot whales presented higher concentrations than sperm whales for ΣPCBs (38666±25731ng.g-1 lw and 22849±15566ng.g-1 lw respectively), ΣPBDEs (712±412ng.g-1 lw and 347±173ng.g-1 lw respectively) and ΣDDTs (46081±37506ng.g-1 lw and 37647±38518ng.g-1 lw respectively). Each species was characterized by large inter-individual variations that could probably be more related to sex than trophic level, with males presenting higher contaminant burden than females. The PCA analysis confirmed how p,p’DDT and p,p’DDE were influential in differentiating the two species, as a consequence of their migratory behavior and distribution. Pollutant concentrations of our species were significantly higher than both their Southern Hemisphere and North Atlantic counterparts, possibly due to the particular Mediterranean geomorphology, which influences pollutants distribution and recycle. Dioxin-like PCBs accounted for over 80% of the total TEQ. This study demonstrated (1) an important exposure to pollutants of Mediterranean toothed-whales, often surpassing the estimated threshold toxicity value of 17000ng.g−1 for blubber in marine mammals1; and (2) how the final pollutant burden in these animals is strongly influenced by numerous ecological factors. [less ▲]

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See detailSpatial variation in the concentrations of mercury and persistent organic pollutants in free-ranging bottlenose dolphins (Tursiops truncatus) from South Florida
Damseaux, France ULg; Kiszka, Jeremy; Heithaus et al

Poster (2014, December 12)

The bottlenose dolphin (Tursiops truncatus) is an abundant apex predator found in nearshore waters of South Florida, especially in the Lower Florida Keys (Key West) and the coastal waters of Everglades ... [more ▼]

The bottlenose dolphin (Tursiops truncatus) is an abundant apex predator found in nearshore waters of South Florida, especially in the Lower Florida Keys (Key West) and the coastal waters of Everglades National Park (ENP). The objective of this study was to assess variation in contamination levels of total mercury (T-Hg) and persistent organic pollutants (NDL-PCBs, PBDEs, DDT, HCH, HCB, PCDD/Fs and DL-PCBs) in bottlenose dolphins found offshore of the densely populated Key West (n = 27) and from undeveloped ENP (n = 20). T-Hg and POPs were analysed in skin and blubber, respectively, by the mean of Direct Mercury analyser (for THg), GC-ECD (POPs) and GC-HRMS (DLCs). The 7 ICES PCBs were the main compounds found in bottlenose dolphins from Key West (8229 ng.g-1 lipids) and the ENP (2289 ng.g-1 lipids), while the concentrations of PCDD/Fs remained low (Key West: 104 pg.g-1 lipids, ENP: 102 ng.g-1 lipids). POP concentrations were higher in individuals from Key West compared to those from the ENP. However, POPs concentrations in Key West dolphins were lower than those from other locations in Florida and around the world. Unlike organic pollutants, T-Hg concentrations were significantly higher in ENP dolphins (Key West: 2941 ng.g-1 dw versus ENP: 9314 ng.g-1 dw) highlighting the specific cycle of Hg in mangrove ecosystems. To conclude, sources of T-Hg and POPs differed between Key West and ENP as reflected by their concentrations in skin and blubber of free-ranging bottlenose dolphins highlighting their role as sentinels of their environment. [less ▲]

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See detailWhen microplastic is not microplastic: ingestion of artificial cellulose fibers by macrofauna living in seagrass macrophytodetritus
Collard, France ULg; Remy, François ULg; Gilbert, Bernard ULg et al

Poster (2014, December 12)

Vagile macroinvertebrates associated with Posidonia oceanica exported litter were sampled in August 2011, November 2011 and March 2012 in the Calvi Bay (Corsica), near the STARESO oceanographic station ... [more ▼]

Vagile macroinvertebrates associated with Posidonia oceanica exported litter were sampled in August 2011, November 2011 and March 2012 in the Calvi Bay (Corsica), near the STARESO oceanographic station. Contents of digestive tracts were analyzed and fibers of various sizes and colors were found. Fibers were found in 27.6% of the digestive tracts in the nine dominant species. No correlation was found between number of fibers and taxonomic or trophic level. There were no seasonal or spatial preferences and thus we hypothesize that the organisms ingest these fibers randomly throughout the year. Analyses performed with a Raman spectroscope showed that these fibers were composed of cellulose associated with a coloring agent following the fiber color. Red fibers were dyed with the Direct Red 28, blue fibers were dyed with Direct Blue 22. Analyses by a scanning electron microscope (SEM) showed that cellulose fibers had the particular morphology of artificial cellulose fibers called: viscose. Our SEM analyses were compared to literature. This comparison assessed that fibers found in digestive tracts were made of viscose. In a first approach, viscose fibers looked like microplastic fibers because of their color and shape. However, it appeared that these fibers were made of artificial cellulose which is very different than plastic in terms of impacts and fate in the organisms. This study highlights the importance of physico-chemical analyses such as Raman spectroscopy and SEM to certainly identify the composition of particles ingested by organisms. From an ecological point of view, the red coloring agent is known to be carcinogenic in mammals and fish. Consequently, this pollution could provoke an environmental problem for the P. oceanica litter vagile macrofauna. [less ▲]

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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, Imen; Leroy, Delphine; Guignard, Cedric et al

in Nutrition Research (2014), 34(12), 1075-1084

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 detailThe use of Ion Mobility Mass Spectrometry for isomer composition determination extracted from Se-rich yeast
Far, Johann ULg; Delvaux, Cédric ULg; Kune, Christopher ULg et al

in Analytical Chemistry (2014), just accepted

The isomer ratio determination of a selenium-containing metabolite produced by Se-rich yeast was performed. Electrospray Ionization and Ion Mobility Mass Spectrometry (IM-MS) were unsuccessfully used in ... [more ▼]

The isomer ratio determination of a selenium-containing metabolite produced by Se-rich yeast was performed. Electrospray Ionization and Ion Mobility Mass Spectrometry (IM-MS) were unsuccessfully used in order to resolve the isomers according to their Collisional Cross Section (CCS) difference. The isomer ratio determination of 2,3-dihydroxypropionylselenocystathionine was performed after multidimensional liquid chromatography preconcentration from a water extract of Se-rich yeast using preparative size exclusion, anion exchange and capillary reverse phase columns coupled to IM-MS. 4’-nitrobenzo-15-crown-5 ether, a Selective Shift Reagent (SSR), was added after the last chromatographic dimension in order to specifically increase the CCS of one of the isomers by the formation of a stable host-guest system with the crown-ether . Both isomers were consequently fully resolved by IM-MS and the relative ratio of the isomers was determined: 11-13% and 87-89%. The present data compared favorably with literature to support the analytical strategy despite the lack of authentic standard for method validation. In addition, computational chemistry methods were successfully applied to design the SSR and to support the experimental data. [less ▲]

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See detailMeasurement uncertainty for persistent organic pollutants by isotope dilution mass spectrometry
Eppe, Gauthier ULg; Diletti, G; Fernandes, A et al

in Organohalogen Compounds (2014, September), 76

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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 detailIdentification of molecular components of the host-microbiota-connectome by using "Omics Approaches"
Mariman, Rob ULg; Coppieters, Wouter ULg; Elansary, Mahmoud ULg et al

Poster (2014, April 24)

The host immune system plays an critical role in maintaining homeostasis with resident microbial communities, therefore ensuring that the complex symbiotic relationship is maintained. At the same time ... [more ▼]

The host immune system plays an critical role in maintaining homeostasis with resident microbial communities, therefore ensuring that the complex symbiotic relationship is maintained. At the same time, resident microbiota contribute to host nutrition and energy balance and to the development or maintenance of a robust immune system. Dysbiosis of the microbiota is associated with various immunological disorders, including inflammatory bowel diseases (IBD). Both genetic and environmental factors are implicated in this disturbance; however, the relative contributions of these two factors, and the mechanism by which they interact remain unclear. Recently, we started a project that aims to identify molecular components of the hostmicrobiota-connectome by taking advantage of common variation in – on the one hand – the genome, transcriptome and metabolome of the host, and – on the other hand – the composition of its gut microbiota. We will take advantage of the already established CEDAR cohort that provides integrated genetic (SNP genotypes) and transcriptome data (circulating immune cells subset, as well as samples from various anatomical locations in the intestine). We will further enrich the dataset in this cohort with metabolome (plasma), and gut microbiota data (16srRNA sampled at the ileum, colon, and rectum). The CEDAR cohort is composed of healthy individuals and is therefore more suitable to study effect of common risk variants than (IBD) patients, since analysis of samples from patients suffering from active inflammation may only give insight in ongoing patho-physiological processes, that are likely to mask the primum movens events. Next, we will study the overlap between the identified components of the HMC network identified and the ~160 GWAS-identified risk loci for IBD. We anticipate to reveal novel connections between the microbiota and IBD by this integrative “omics” approach, thereby shedding new light on the pathogenesis of IBD. Latest results will be presented with respect to the microbiota composition of from different anatomical locations in the intestine using the V2 and V5-6 regions of the bacterial 16S rRNA. [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 detailValidated ready-to-use GC-MS/MS method for dioxin analysis in food and feed following the new EU Regulations
l'homme, Benjamin; Sandy, Chris; Scholl, Georges ULg et al

in Organohalogen Compounds (2014), 76

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See detailKinetic study of volatile oil of Curcuma longa L. rhizome and Carum carvi L. fruits extracted by microwave-assisted techniques using the cryogrinding
Akloul, R; Benkaci-Ali, F; Eppe, Gauthier ULg

in Journal of Essential Oil Research (2014), 26(6), 473-485

Hydrodistillation assisted by microwave (HDAM) and steam distillation assisted by microwave (SDAM) of Curcuma longa L. rhizome (CL) and Carum carvi fruits (CC) were investigated. The effect of the ... [more ▼]

Hydrodistillation assisted by microwave (HDAM) and steam distillation assisted by microwave (SDAM) of Curcuma longa L. rhizome (CL) and Carum carvi fruits (CC) were investigated. The effect of the cryogrinding (CG) showed differences in yields and composition of volatile oils compared with classical grinding. HDAM–CG (CL: 1.20%, CC: 1.25%) and SDAM–CG (CL: 1.45%, CC: 1.75%) allowed extraction of substantial amounts of volatile oils in less time compared with HDAM (CL: 0.6%, CC: 1.00%) and SDAM (CL: 0.90%, CC: 1.00%). In addition, the major amounts of volatile oils were globally obtained during the first 5 and 10 minutes of extraction for CL and CC, respectively. A kinetic study of essential oils extraction from CL and CC was quantitatively performed. The composition of the major components and family classes present a significant variation with the extraction time. Essential oils extracted by these two methods were quantitatively (yield) and qualitatively [aromatic profile by gas chromatography (GC) and GC–mass spectrometry (GC–MS)] analyzed. There were differences, especially in the major compounds ar-turmerone (HDAM: 46.00–57.96%, HDAM–CG: 30.85–60.32%) and β-turmerone (HDAM: 14.43–16.74%, HDAM–CG: 10.46–15.77%) for CL, and limonene (HDAM: 23.61–56.97%, HDAM–CG: 38.04–43.00%) and carvone (HDAM: 36.19–64.54%, CC–CG: 53.65–56.31%) for CC. [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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