Browsing
     by title


0-9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

or enter first few letters:   
OK
Full Text
Peer Reviewed
See detailCobblestone-like brain dysgenesis and altered glycosylation in congenital cutis laxa. Debre type
Van Maldergem, Lionel ULg; Yuksel-Apak, M.; Kayserili, H. et al

in Neurology (2008), 71(20), 1602-1608

Detailed reference viewed: 13 (0 ULg)
Full Text
Peer Reviewed
See detailCocaine and Amphetamine-Regulated-Transcript Peptide Mediation of Leptin Stimulatory Effect on the Rat Gonadotropin-Releasing Hormone Pulse Generator in Vitro
LEBRETHON, Marie-Christine ULg; Vandersmissen, E.; Gerard, Arlette ULg et al

in Journal of Neuroendocrinology (2000), 12(5), 383-5

Pulsatile gonadotropin-releasing hormone (GnRH) secretion was studied in vitro using explants of the retrochiasmatic hypothalamus from prepubertal male and female rats. Leptin caused a dose-dependent ... [more ▼]

Pulsatile gonadotropin-releasing hormone (GnRH) secretion was studied in vitro using explants of the retrochiasmatic hypothalamus from prepubertal male and female rats. Leptin caused a dose-dependent reduction of the GnRH interpulse interval in both sexes. We studied the effects of cocaine- and amphetamine-regulated transcript (CART) since this peptide was shown recently to mediate the anorectic effects of leptin in the hypothalamus. CART caused a reduction of the GnRH interpulse interval. This effect was prevented using an anti-CART antiserum which could partially overcome leptin stimulatory effects as well. Using hypothalamic explants from Zucker rats homozygous for the leptin receptor mutation ( fa/fa), GnRH pulse frequency was not affected by leptin, while a significant acceleration was caused by the CART-peptide. In conclusion, leptin involves the hypothalamic CART-peptide to stimulate the prepubertal GnRH pulse generator in vitro. [less ▲]

Detailed reference viewed: 7 (1 ULg)
Peer Reviewed
See detailCocaïne and metabolites in waste and surface water across Belgium - a monitoring study
Van Nuijs, Alexander; Pecceu, Bert; Gheorghe, A. et al

Poster (2008)

Detailed reference viewed: 29 (8 ULg)
Full Text
Peer Reviewed
See detailCocaïne and metabolites in waste and surface water across Belgium.
Van Nuijs, Alexander; Pecceu, Bert; Theunis, Laetitia ULg et al

in Environmental Pollution (2009), 157

Detailed reference viewed: 88 (46 ULg)
Full Text
Peer Reviewed
See detailCocaïne dans nos rivières : une approche méthodologique originale dans le domaine de la toxicologie environnementale
Theunis, Laetitia ULg; van Nuijs, Alexander; Pecceu, Bert et al

in Revue Médicale de Liège (2008), 63(S1), 39-43

Detailed reference viewed: 101 (32 ULg)
See detailCOcaine in WATer
Theunis, Laetitia ULg; Dubois, Nathalie ULg; Van Nuijs, Alexander et al

Poster (2008, September)

Detailed reference viewed: 23 (4 ULg)
Full Text
Peer Reviewed
See detailCocaine-conditioned activity persists for a longer time than cocaine-sensitized activity in mice: Implications for the theories using Pavlovian excitatory conditioning to explain the context-specificity of sensitization
Tirelli, Ezio ULg; Michel, Alexa ULg; Brabant, Christian ULg

in Behavioural Brain Research (2005), 165(1), 18-25

The present study was aimed at testing the prediction of the Pavlovian excitatory conditioning explanation of context-specific sensitization that the sensitized effect (SE) should persist as long as the ... [more ▼]

The present study was aimed at testing the prediction of the Pavlovian excitatory conditioning explanation of context-specific sensitization that the sensitized effect (SE) should persist as long as the post-sensitization conditioned activity (CR). C57BL/6J mice were tested for the expression of cocaine-induced conditioned and sensitized locomotion on several intervals after the establishment of a sensitization in an unchanging context. A group of mice received 10 once-daily injections of 10 mg/kg cocaine (s.c.) in a short time prior to being tested in activity-meters for 60 min sessions (cocaine-pretreated group), mice from a control group receiving saline in the same manner (saline-pretreated group). On the test sessions, taking place 1, 8 and 28 days after cocaine pretreatment, half of the animals of each pretreatment group (n=8) received a challenge test with saline and the other half with 10 mg/kg cocaine in the pretreatment context room (for CR and SE tests, respectively). The CR was significantly expressed on the three successive saline-challenge tests, albeit the activity levels were markedly decreased on the 28-day retention test. In contrast, the SE was significantly expressed only during the first half of the 1-day test session and the first 10 min of the 8-day test session, no SE effect being expressed on the 28-day retention test. The results, suggesting a functional uncoupling of the CR from the SE, disprove the theories of context-specificity of sensitization based completely or partially on Pavlovian excitatory conditioning mechanisms. [less ▲]

Detailed reference viewed: 34 (3 ULg)
See detailCocaïne: Détermination du délai entre le prélèvement et la consommation
De Backer, Benjamin ULg

Conference (2008, November 14)

Detailed reference viewed: 26 (6 ULg)
Full Text
Peer Reviewed
See detailLa coccinelle asiatique est-elle l'aphidiphage dominant dans les agro-écosystemes ?
Vandereycken, Axel ULg; Durieux, Delphine ULg; Joie, Emilie ULg et al

Conference (2011, October 26)

La coccinelle asiatique, Harmonia axyridis Pallas, importée en Europe de l'Ouest afin de lutter contre les pucerons et les cochenilles, s'y est rapidement acclimatée. Cette espèce exotique est devenue ... [more ▼]

La coccinelle asiatique, Harmonia axyridis Pallas, importée en Europe de l'Ouest afin de lutter contre les pucerons et les cochenilles, s'y est rapidement acclimatée. Cette espèce exotique est devenue invasive et exerce un impact négatif sur la biodiversité en entrant en prédation intraguilde avec les espèces natives. Afin d'évaluer l'importance de l'invasion de cette espèce exotique, un inventaire des prédateurs de pucerons a été réalisé en 2009 et 2010 au sein de quatre cultures : maïs, froment, pomme de terre et fève des marais, situées dans le Sud de la Belgique. Cinq espèces aphidiphages majoritaires ont été observées; par ordre décroissant d'importance: Episyrphus balteatus (De Geer), Chrysoperla carnea sensus lato (Stephens), Coccinella septempunctata (Linné), Harmonia axyridis Pallas et Propylea quatuordecimpunctata (Linné). La coccinelle asiatique ne représente que 8,7 % de tous les prédateurs de pucerons observés et 23,9% de toutes les coccinelles. De plus, elle est deux fois moins abondante que la coccinelle à sept points. Cette espèce invasive n'est donc actuellement pas l'aphidiphage le plus abondant dans les agro-écosystèmes wallons. [less ▲]

Detailed reference viewed: 58 (19 ULg)
Full Text
Peer Reviewed
See detailLa coccinelle asiatique est-elle l'aphidiphage dominant dans les agro-écosystèmes ?
Vandereycken, Axel ULg; Durieux, Delphine ULg; Joie, Emilie ULg et al

in 9ème Conférence Internationale sur les Ravageurs en Agriculture, Montpellier 26-27 octobre 2011 (2011)

The Asian ladybird, Harmonia axyridis Pallas (Coleoptera: Coccinellidae), has been introduced in Western Europe to control aphid and coccid populations in greenhouses. This exotic species rapidly adapted ... [more ▼]

The Asian ladybird, Harmonia axyridis Pallas (Coleoptera: Coccinellidae), has been introduced in Western Europe to control aphid and coccid populations in greenhouses. This exotic species rapidly adapted to temperate climatic conditions and invaded all Europe in few years. Now, H. axyridis is causing damages to the ecosystems through e.g. intraguild predation (IGP) with native species. We evaluated, in 2009 and 2010, the occurrence of aphid natural enemies (hoverflies, coccinellids and lacewings) in several agro-ecosystems (corn, wheat, potato, broad bean) in northern Wallonia (Belgium). Five dominating aphidophagous species were observed, in decreasing order of importance: Episyrphus balteatus (De Geer), Chrysoperla carnea sensus lato (Stephens), Coccinella septempunctata (Linné), Harmonia axyridis and Propylea quatuordecimpunctata (Linné). The Multicolored Asian ladybird represents 8,7% of all observed aphidophagous species and 23,9% of coccinellids. Moreover, H. axyridis occurrence is two-times less important than C. 7-punctata. These results highlight that this invasive species is currently not the most abundant in southern Belgium agro-ecosystems and would not influence other aphid predators in those particular ecosystems. [less ▲]

Detailed reference viewed: 85 (15 ULg)
Full Text
See detailCoccolithophore bloom dynamics shape bacterioplankton communities in the northern Bay of Biscay
Van Oostende, Nicolas; Vyverman, Wim; Harlay, Jérôme ULg et al

Poster (2008, August 17)

Coccolithophores (Prymnesiophyceae) such as Emiliania huxleyi belong to the most productive calcifying organisms in the oceans. During two consecutive years we assessed bacterial diversity and dynamics ... [more ▼]

Coccolithophores (Prymnesiophyceae) such as Emiliania huxleyi belong to the most productive calcifying organisms in the oceans. During two consecutive years we assessed bacterial diversity and dynamics during the course of spring phytoplankton blooms dominated by coccolithophores in the northern part of the Bay of Biscay. Bacterioplankton community composition was assessed by means of denaturing gradient gel electrophoresis (DGGE) in combination with 16S rRNA gene clone libraries. We used ordination analysis to relate bacterioplankton community dynamics to phytoplankton pigment data and environmental parameters (nutrient concentrations, total alkalinity, concentration of transparent exopolymeric particles (TEP), pCO2). We found a clear difference in composition between the free-living and the particle-associated bacterial assemblage, with the identified Flavobacteria and Sphingobacteria phylotypes being characteristic for the particle-associated bacterial assemblage and Alfaproteobacteria and members of the SAR86 cluster dominating the free-living bacterial assemblage. Stations along the continental margin, at different stages in the coccolithophore bloom, were characterized by distinct bacterial assemblages which correlated well with changes in phytoplankton community composition and TEP abundance. We hypothesize that coccolithophore bloom dynamics shape both the free-living and the particle associated bacterial assemblages through phytoplankton group-specific associations and TEP production [less ▲]

Detailed reference viewed: 27 (0 ULg)
Full Text
See detailCoccolithophore blooms in the Bay of Biscay: Results from the PEACE project
Harlay, Jérôme ULg; Chou, Lei; Sabbe, Koen et al

Conference (2013, May 15)

Pelagic and benthic processes were determined in the nothern Bay of Biscay when coccolithophores blooms occured between 2006 and 2008. Here we present a synthesis of pelagic primary production ... [more ▼]

Pelagic and benthic processes were determined in the nothern Bay of Biscay when coccolithophores blooms occured between 2006 and 2008. Here we present a synthesis of pelagic primary production, calcification and respiration and benthic respiration and dissolution of CaCO3. Or results suggest that CaCO3 dissolution in the surface sediments is small (~1%) compared to integrated pelagic calcification. Benthic respiration increases with the organic load of the sediment and represents ~8% of the integrated pelagic respiration. The relationship between dissolution and respiration rates suggests a metabolic driven dissolution in waters supersaturated with respect to calcite (omega>3.5). We address a mass balance of the described processes and associated CO2 fluxes in the water column. [less ▲]

Detailed reference viewed: 32 (5 ULg)
Full Text
See detailCoccolithophores at the continental margin: Biogeochemical aspects of bloom formation and development
Harlay, Jérôme ULg

Scientific conference (2009, June 22)

Coccolithophores are probably the most important pelagic producers of calcium carbonate and perhaps the most important contributor to contemporary calcium carbonate production. The accumulation in the ... [more ▼]

Coccolithophores are probably the most important pelagic producers of calcium carbonate and perhaps the most important contributor to contemporary calcium carbonate production. The accumulation in the photic zone of the calcite produced during the blooms of the most common species, Emiliania huxleyi, produces high-reflectance (HR) patches visible from space. In the context of global warming and ocean acidification, there remain some doubts regarding the future of this group and the carbon (C) fluxes associated to coccolithophorid blooms at the global scale. A multi-year survey of coccolithophorid blooms, from 2002 to 2008, was carried out along the continental margin of the northern Bay of Biscay and focused on pelagic processes. Based on the hydrographic and biogeochemical data obtained during those campaigns and the analysis of satellite images of sea surface temperature, chlorophyll-a concentration and reflectance, we describe the properties of the HR patches in this region and emphasize on the ecological niche of E. huxleyi. This study offered the opportunity to investigate the impact of coccolithophorid blooms on the exchange of carbon dioxide (CO2) at the air-sea interface and the coupling between primary production and calcification in the field, as determined by 14C incorporation. The distribution of transparent exopolymer particles (TEP) was investigated and the production of TEP is proposed as a mechanism for bloom termination, the critical step leading to massive export depth. Supra-lysoclinal dissolution of coccoliths, as supported by the analysis of scanning electron micrographs, will be discussed in combination with the formation of aggregates to provide a scheme of the onset of the coccolithophorid bloom to its decay. [less ▲]

Detailed reference viewed: 25 (1 ULg)
Full Text
See detailCoccolithophorid calcium carbonate dissolution in surface waters
Harlay, Jérôme ULg; Koch, Craig; Young, Jeremy R et al

Poster (2007, March 06)

The role of calcifying organisms in the ocean biogeochemistry has been receiving increasing attention since CO2-related global change issues such as ocean acidification were pointed out by the scientific ... [more ▼]

The role of calcifying organisms in the ocean biogeochemistry has been receiving increasing attention since CO2-related global change issues such as ocean acidification were pointed out by the scientific community. The implications of changing oceanic pH in modifying ecosystems dominated by planktonic calcifiers have been shown by mesocosm and laboratory experiments based on CO2 manipulations. The major concern of such experiments focussed on variations in the rates of ecosystem primary production and calcification due to changes in algal physiology or specific composition. Our results, from an interdisciplinary survey of coccolithophore-dominated blooms in the northern Bay of Biscay (NE Atlantic), suggest that biogenic calcite dissolution is occurring in the photic zone where surface waters are oversaturated with respect to calcite. The dissolution of CaCO3 in surface waters, evidenced by scanning electron microscopy observations, has an impact on the preservation and export of carbon in coccolithophore-dominated ecosystems and on the exchange of CO2 across the ocean-atmosphere interface. Both aspects of suspended calcite concentration reduction in natural environments (lower rates of production or dissolution) could be considered as a perturbation of the oceanic carbon cycle. We aim at presenting here a biogeochemical description of processes, including integrated primary production, calcification, and parameters such as transparent exopolymer particles concentration and particulate inorganic carbon profiles, during field studies. A mechanism for calcite dissolution, based on biological activity in microenvironments (including grazing, bacterial respiration and DMS production) is presented as a conceptual model in coccolithophore blooms. [less ▲]

Detailed reference viewed: 29 (1 ULg)
See detailCoccolithophorid Emiliania huxleyi to elevated pCO2 under nitrate limitation
Sciandra, Antoine; Harlay, Jérôme ULg; Lefèvre, Dominique et al

Conference (2003, April 06)

The effects of a partial pressure of CO2 (pCO2) increased from 400 to 700 ppm on nitrogen-limited growing cells of the coccolithophore Emiliania huxleyi were studied. Nitrogen limitation was obtained ... [more ▼]

The effects of a partial pressure of CO2 (pCO2) increased from 400 to 700 ppm on nitrogen-limited growing cells of the coccolithophore Emiliania huxleyi were studied. Nitrogen limitation was obtained within NO3-limited continuous cultures renewed at the rate of 0.5 d−1 and submitted to saturating light level. pCO2 was controlled by bubbling CO2-rich or CO2-free air in the cultures. It is shown that the increase of pCO2 has a rapid effect on cell physiology taking place within the 2 cell divisions occurring after the perturbation. Net calcification rate (C) was depressed from approximately 25%, and, as opposed to what has been reported by previous studies on N-replete cultures, net community production (NCP) was depressed in the same proportion. These results therefore suggest that the increase of pCO2 had not noticeable effect on the calcification/photosynthesis ratio (C/P) when cells of E. huxleyi are NO3-limited. [less ▲]

Detailed reference viewed: 18 (3 ULg)