References of "Compère, Philippe"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailHistopathological effects of Aspergillus clavatus (Ascomycota: Trichocomaceae) on larvae of the southern house mosquito, Culex quinquefasciatus (Diptera: Culicidae)
Bawin, Thomas ULg; Seye, Fawrou; Boukraa, Slimane ULg et al

in Fungal Biology (2016), 120(4), 489-499

Aspergillus clavatus (Ascomycota: Trichocomaceae) was previously found to be an opportunistic pathogen of mosquitoes (Diptera: Culicidae). In the present study, the mechanism leading to its insecticidal ... [more ▼]

Aspergillus clavatus (Ascomycota: Trichocomaceae) was previously found to be an opportunistic pathogen of mosquitoes (Diptera: Culicidae). In the present study, the mechanism leading to its insecticidal activity was investigated regarding histological damages on Culex quinquefasciatus larvae exposed to A. clavatus spores. Multiple concentration assays using spore suspensions (0.5 x 10^8 to 2.5 x 10^8 spores/ml) revealed 17.0% to 74.3% corrected mortalities after 48 h exposure. Heat-deactivated spores induced a lower mortality compared to non-heated spores suggesting that insecticidal effects are actively exerted. Spore-treated and untreated larvae were prepared for light microscopy as well as for scanning and transmission electron microscopy. Spores failed to adhere to the external body surface (except the mouth parts) of these aquatic immature stages but progressively filled the digestive tract where their metabolism seemed to activate. In parallel, the internal tissues of the larvae, i.e. the midgut wall, the skeletal muscles, and the cuticle-secreting epidermis, were progressively destroyed between 8 and 24 h of exposure. These observations suggest that toxins secreted by active germinating spores of A. clavatus in the digestive tract altered the larval tissues, leading to their necrosis and causing larval death. Fungal proliferation and sporulation then occurred during a saprophytic phase. A. clavatus enzymes or toxins responsible for these pathogenic effects need to be identified in further studies before any use of this fungus in mosquito control. [less ▲]

Detailed reference viewed: 71 (21 ULg)
Peer Reviewed
See detailMicroanalyzes of remarkable microfossils of the Late Mesoproterozoic–Early Neoproterozoic
Cornet, Yohan ULg; Beghin, Jérémie ULg; Kabamba Baludikay, Blaise ULg et al

in European Geosciences Union General Assembly 2016 Vienna, Austria, 2016 (2016)

Detailed reference viewed: 19 (8 ULg)
Full Text
See detailContribution of cyanobacteria to the building of travertines in a calcareous stream
Wilmotte, Annick ULg; Golubic, Stjepko; Kleinteich, Julia et al

Poster (2015, August 03)

The ambient temperature travertine deposits of the calcareous Hoyoux River (Modave, Belgium) and several tributaries are organized and promoted by the filamentous cyanobacterium identified by its ... [more ▼]

The ambient temperature travertine deposits of the calcareous Hoyoux River (Modave, Belgium) and several tributaries are organized and promoted by the filamentous cyanobacterium identified by its morphotype and ecological properties as Phormidium cf. incrustatum. A combination of techniques was used to study this biotope: physico-chemical parameters and CO2 measurements, Scanning and Transmission Electron Microscopy, RAMAN microspectroscopy. A molecular diversity study with pyrosequencing of the cyanobacterial 16S rRNA is in progress. A potential candidate was isolated in culture. [less ▲]

Detailed reference viewed: 64 (3 ULg)
Full Text
Peer Reviewed
See detailChitosan enriched three-dimensional matrix reduces inflammatory and catabolic mediators production by human chondrocytes
Oprenyeszk, Frédéric ULg; Sanchez, Christelle ULg; Dubuc, Jean-Emile et al

in PLoS ONE (2015), 10(5),

This in vitro study investigated the metabolism of human osteoarthritic (OA) chondrocytes encapsulated in a spherical matrix enriched of chitosan. Human OA chondrocytes were encapsulated and cultured for ... [more ▼]

This in vitro study investigated the metabolism of human osteoarthritic (OA) chondrocytes encapsulated in a spherical matrix enriched of chitosan. Human OA chondrocytes were encapsulated and cultured for 28 days either in chitosan-alginate beads or in alginate beads. The beads were formed by slowly passed dropwise either the chitosan 0.6%- alginate 1.2% or the alginate 1.2% solution through a syringe into a 102 mM CaCl2 solution. Beads were analyzed histologically after 28 days. Interleukin (IL)-6 and -8, prostaglandin (PG) E2, matrix metalloproteinases (MMPs), hyaluronan and aggrecan were quantified directly in the culture supernatant by specific ELISA and nitric oxide (NO) by using a colorimetric method based on the Griess reaction. Hematoxylin and eosin staining showed that chitosan was homogeneously distributed through the matrix and was in direct contact with chondrocytes. The production of IL-6, IL-8 and MMP-3 by chondrocytes significantly decreased in chitosan-alginate beads compared to alginate beads. PGE2 and NO decreased also significantly but only during the first three days of culture. Hyaluronan and aggrecan production tended to increase in chitosan-alginate beads after 28 days of culture. Chitosan-alginate beads reduced the production of inflammatory and catabolic mediators by OA chondrocytes and tended to stimulate the synthesis of cartilage matrix components. These particular effects indicate that chitosan-alginate beads are an interesting scaffold for chondrocytes encapsulation before transplantation to repair cartilage defects. [less ▲]

Detailed reference viewed: 125 (31 ULg)
See detailCyanobacteria - the constructors of travertines?
Kleinteich, Julia; Stelmach Pessi, Igor ULg; Velazquez, David et al

Conference (2015, February)

Cyanobacteria are participating in carbonate build-up and travertine formation in the Belgian river Hoyoux and its tributaries. In this study, we sampled calcareous material from travertines and oncoliths ... [more ▼]

Cyanobacteria are participating in carbonate build-up and travertine formation in the Belgian river Hoyoux and its tributaries. In this study, we sampled calcareous material from travertines and oncoliths from four sampling sites on the Hoyoux river and Triffoy brook. In addition, the water chemistry was determined. The structure of the material was analyzed by Scanning Electron Microscopy and Raman microscopy (?°. The dominant cyanobacterial species was isolated and identified on the basis of microscopic observation and amplification of the 16S-ITS fragment as Phormidium sp., likely functioning as the ‘architect’ of the travertine system. In order to describe the full diversity of the travertine system and to discriminate between the active fraction and inactive or dead organic matter, DNA as well as RNA was extracted from the travertine material, amplified using cyanobacteria specific primers and sequenced by 454 pyrosequencing. To detect seasonal changes in the biological activity, summer and winter time points were compared. This study reveals the ecology of an overlooked environment in Belgian river systems and tries to explain the build-up of travertines. [less ▲]

Detailed reference viewed: 100 (19 ULg)
Full Text
Peer Reviewed
See detailSEM and EDS observations of carrollite bioleaching with a mixed culture of acidophilic bacteria
Nkulu, Guy; Gaydardzhiev, Stoyan ULg; Mwema, Edouard et al

in Minerals Engineering (2015), doi:10.1016/j.mineng.2014.12.005

Bioleaching of high purity carrollite minerals with mesophilic bacteria was carried out and monitored by observations in scanning electron microscopy (SEM) and elemental X-ray microanalysis (EDS) to ... [more ▼]

Bioleaching of high purity carrollite minerals with mesophilic bacteria was carried out and monitored by observations in scanning electron microscopy (SEM) and elemental X-ray microanalysis (EDS) to provide evidence of the interaction pattern between carrollite and microorganisms. A bacterial consortium involving three different acidophilic chemolithotrophs was adopted. The evolution of the surface topography, inside alteration effects and elemental composition of the mineral with leaching time was followed. It could be postulated that bacterial adhesion takes place on the mineral surface, resulting in the formation of dissolution pits of various shapes and continues by boring elongated channels deep inside the mineral grains. Enhanced concentration of ferric iron and sulphur could be assumed in vicinity of the zones where mineralized polymer substances are precipitated. It could be inferred that carrollite dissolution is governed by cooperative bioleaching involving oxidation induced by bacteria attached to the surface and ferric iron re-oxidized by planktonic bacteria in suspension. [less ▲]

Detailed reference viewed: 71 (22 ULg)
Full Text
Peer Reviewed
See detailWhen microplastic is not plastic: the ingestion of artificial cellulose fibers by macrofauna living in seagrass macro-phytodetritus.
Remy, François ULg; Collard, France ULg; Gilbert, Bernard ULg et al

in Environmental Science & Technology (2015), 49

Dead leaves of the Neptune grass, Posidonia oceanica (L.) Delile, in the Mediterranean coastal zone, are colonized by an abundant “detritivorous” invertebrate community that is heavily predated by fishes ... [more ▼]

Dead leaves of the Neptune grass, Posidonia oceanica (L.) Delile, in the Mediterranean coastal zone, are colonized by an abundant “detritivorous” invertebrate community that is heavily predated by fishes. This community was sampled in August 2011, November 2011 and March 2012 at two different sites in the Calvi Bay (Corsica). Ingested artificial fibers (AFs) of various sizes and colors were found in 27.6% of the digestive tracts of the nine dominant species regardless of their trophic level or taxon. No seasonal, spatial, size or species-specific significant differences were revealed; suggesting that invertebrates ingest AFs at constant rates. Results showed that, in the gut contents of invertebrates, varying by trophic level, and across trophic levels, the overall ingestion of AFs was low (approximately 1 fiber per organism). Raman spectroscopy revealed that the ingested AFs were composed of viscose, an artificial, cellulose-based polymer. Most of these AFs also appeared to have been colored by industrial dyes. Two dyes were identified: Direct Blue 22 and Direct Red 28. The latter is known for being carcinogenic for vertebrates, potentially causing environmental problems for the P. oceanica litter community. Techniques such as Raman spectroscopy are necessary to investigate the particles composition, instead of relying on fragment size or color to identify the particles ingested by animals. [less ▲]

Detailed reference viewed: 129 (43 ULg)
Full Text
Peer Reviewed
See detailCorrelation between morphology and electrical conductivity of dried and carbonized multi-walled carbon nanotube/resorcinol–formaldehyde xerogel composites
Haghgoo, M.; Yousefi, A. A.; Mehr, M. J. Z. et al

in Journal of Materials Science (2015), 20

Detailed reference viewed: 100 (17 ULg)
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 212 (14 ULg)
Full Text
Peer Reviewed
See detailMoult-related changes in the integument, midgut, and digestive gland in the freshwater amphipod gammarus pulex
Trevisan, Mélissa ULg; Leroy, Delphine; Decloux, Nicole ULg et al

in Journal of Crustacean Biology (2014), 34(5), 539-551

On the basis of macroscopic aspects (body and eye colour, lipid droplets), it was possible to sort specimens of Gammarus pulex (Linnaeus, 1758) into five categories that correspond to moult periods and ... [more ▼]

On the basis of macroscopic aspects (body and eye colour, lipid droplets), it was possible to sort specimens of Gammarus pulex (Linnaeus, 1758) into five categories that correspond to moult periods and stages (A, B, C, D1 and D2) based on integument features (tergite cuticle stiffness, layers and thickness). These stages also correspond to changes in digestive tract histology (gut content, cell ultrastructure, and lipid storage). With reference to the pereion tergite integument, this makes it possible to standardize moulting stage terminology and criteria with those applied to decapods while validating a quick, simple, moult-staging method that avoids injury and informs us about the physiology of the whole organism. The moult cycle was very short (about 12-15 days), with a "virtual," practically non-existent, anecdysis or "integument resting period" between post-ecdysis and pre-ecdysis. The pore canals previously known to be "open to the outside" appeared closed at early post-ecdysis by a lipid-rich fillng material that could be responsible for the cuticular waterproofing barrier allowing mineral deposition. In the digestive tract, the main structural changes were late post-ecdysial loss of midgut cells and digestive gland B-cells (probably by extrusion) when restarting the feeding cycle. Pre-ecdysial increase and post-ecdysial decrease in storage lipids are also obvious. We present a quick moult-staging method to sort a great number of G. pulex for physiological or toxicological assays investigating how animals at specific periods of their moult cycle respond to both natural and anthropogenic environmental changes. [less ▲]

Detailed reference viewed: 44 (16 ULg)
Full Text
Peer Reviewed
See detailOrganic and mineral imprints in fossil photosynthetic mats of an East Antarctic lake
Lepot, Kevin; Compère, Philippe ULg; Gerard, E et al

in Geobiology (2014), 12(5), 424-450

Detailed reference viewed: 39 (8 ULg)
Full Text
Peer Reviewed
See detailProperties, morphogenesis, and effect of acidification on spines of the cidaroid sea urchin Phyllacanthus imperialis
Dery, A.; Guibourt, V.; Catarino, A. I. et al

in Invertebrate Biology (2014), 133(2), 188-199

Cidaroid sea urchins are the sister clade to all other extant echinoids and have numerous unique features, including unusual primary spines. These lack an epidermis when mature, exposing their high ... [more ▼]

Cidaroid sea urchins are the sister clade to all other extant echinoids and have numerous unique features, including unusual primary spines. These lack an epidermis when mature, exposing their high-magnesium calcite skeleton to seawater and allowing the settlement of numerous epibionts. Cidaroid spines are made of an inner core of classical monocrystalline skeleton and an outer layer of polycrystalline magnesium calcite. Interestingly, cidaroids survived the Permian-Triassic crisis, which was characterized by severe acidification of the ocean. Currently, numerous members of this group inhabit the deep ocean, below the saturation horizon for their magnesium calcite skeleton. This suggests that members of this taxon may have characteristics that may allow them to resist ongoing ocean acidification linked to global change. We compared the effect of acidified seawater (pH 7.2, 7.6, or 8.2) on mature spines with a fully developed cortex to that on young, growing spines, in which only the stereom core was developed. The cortex of mature spines was much more resistant to etching than the stereom of young spines. We then examined the properties of the cortex that might be responsible for its resistance compared to the underlying stereomic layers, namely morphology, intramineral organic material, magnesium concentration, intrinsic solubility of the mineral, and density. Our results indicate that the acidification resistance of the cortex is probably due to its lower magnesium concentration and higher density, the latter reducing the amount of surface area in contact with acidified seawater. The biofilm and epibionts covering the cortex of mature spines may also reduce its exposure to seawater. © 2014, The American Microscopical Society, Inc. [less ▲]

Detailed reference viewed: 27 (6 ULg)
Full Text
Peer Reviewed
See detailNew insights into the role of the pharyngeal jaw apparatus in the sound producing mechanism of Haemulon flavolineatum (Haemulidae)
Bertucci, Frédéric ULg; Ruppé, Laetitia; Van Wassenbergh, Sam et al

in Journal of Experimental Biology (2014), 217

Detailed reference viewed: 28 (7 ULg)
Full Text
Peer Reviewed
See detailDentinal tubules sealing by means of diode lasers (810 and 980 nm): A preliminary in vitro study
Umana, M.; Heysselaer, D.; Compère, Philippe ULg et al

in Photomedicine and Laser Surgery (2013), 31(7), 307-314

Objective: The aim of this study was to evaluate the effect on dentinal surfaces of diode lasers (810 and 980 nm) at different parameters. Materials and methods: Twenty-four caries-free human impacted ... [more ▼]

Objective: The aim of this study was to evaluate the effect on dentinal surfaces of diode lasers (810 and 980 nm) at different parameters. Materials and methods: Twenty-four caries-free human impacted wisdom teeth were used. The crowns were sectioned transversely in order to expose the dentin. The smear layer was removed by a 1 min application of ethylenediaminetetraacetic acid (EDTA). Each surface was divided into four quadrants irradiated at a different output power setting for each kind of laser: 0.8, 1, 1.6, and 2 W (energy densities: 2547, 3184, 5092, and 6366 J/cm2, irradiation speed 1 mm/sec; optical fiber diameter: 200 μm; continuous and noncontact mode). Half of the samples were stained with a graphite paste. All specimens were sent for scanning electron microscopic (SEM) analysis. Pulp temperature increases in additional 20 teeth were measured by a thermocouple. Results: Diode laser irradiations at 0.8 and 1 W led to occlusion or narrowing of dentin tubules without provoking fissures or cracks. The application of graphite paste increased the thermal effects in dentin. Measurements of pulp temperature showed that irradiations at 0.8 and 1 W for a period of 10 sec in continuous mode increased pulp temperature (T ≤2 C). Conclusions: Diode lasers (810 and 980 nm) used at 0.8 and 1 W for 10 sec in continuous mode were able to seal the dentin tubules. These parameters can be considered harmless for pulp vitality, and may be effective in the treatment of dentinal hypersensitivity. © Copyright 2013, Mary Ann Liebert, Inc. 2013. [less ▲]

Detailed reference viewed: 64 (11 ULg)
Full Text
Peer Reviewed
See detailAntarctic urchin ctenocidaris speciosa spines: Lessons from the deep
Catarino, A. I.; av FD Roosevelt 50, Brussels; Guibourt, V. et al

in Cahiers de Biologie Marine (2013), 54(4), 649-655

Ocean acidification is leading to changes in the oceanic carbonate system. As a result, calcium carbonate saturation horizon is shallowing, especially at high latitudes. Biogenic high magnesium-calcites ... [more ▼]

Ocean acidification is leading to changes in the oceanic carbonate system. As a result, calcium carbonate saturation horizon is shallowing, especially at high latitudes. Biogenic high magnesium-calcites could be particularly vulnerable, since their solubility is either similar or greater than that of aragonite. Cidaroid urchins have magnesium-calcite spines covered by a polycrystalline cortex which becomes exposed to seawater when mature (not covered by an epidermis). However, deep species live at low calcium carbonate saturation states, especially at high latitudes. We describe here the morphology and the magnesium content of Ctenocidaris speciosa spines collected at different depths from the Weddell Sea (Antarctica) and relate the features with seawater calcium carbonate saturation. We observed that the spines cortex of C. speciosa presented a thicker inner cortex layer and a lower [Mg2] below the aragonite saturation horizon. We suggest that the cortex of cidaroid spines is able to resist to low calcium carbonate saturation state. [less ▲]

Detailed reference viewed: 32 (3 ULg)
Full Text
Peer Reviewed
See detailInorganic carbon fixation by chemosynthetic ectosymbionts and nutritional transfers to the hydrothermal vent host-shrimp Rimicaris exoculata
Ponsard, Julie ULg; Cambon-Bonavita, Marie-Anne; Zbinden, Magali et al

in ISME Journal (The) (2013), 7

Detailed reference viewed: 298 (100 ULg)
Full Text
Peer Reviewed
See detailThe barbel-like specialization of the pelvic fins in Ophidion rochei (Ophidiidae)
Codina, Elisabet; Kever, Loïc ULg; Compère, Philippe ULg et al

in Journal of Morphology (2012), 273(12), 1367-1376

Detailed reference viewed: 33 (8 ULg)
Full Text
Peer Reviewed
See detailHistological assessment of gonad maturation in Labeo parvus (Teleostei: Cyprinidae) in Benin
Montchowui, Elie; Compère, Philippe ULg; Thiry, Marc ULg et al

in African Journal of Aquatic Science (2012), 37(2), 155-163

Detailed reference viewed: 51 (8 ULg)