References of "Dubois, Philippe"
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See detailPhenology of farmed seaweed Kappaphycus alvarezii infestation by the parasitic epiphyte Polysiphonia sp. in Madagascar
Tsiresy, Gaëtan; Preux, Jérémy; Lavitra, Thierry et al

in Journal of Applied Phycology (in press)

epiphytic filamentous algae (EFA) disease has appeared in many regions of Madagascar. This infestation has dramatic consequences for local farmers as it alters drastically farmed algal growth and has ... [more ▼]

epiphytic filamentous algae (EFA) disease has appeared in many regions of Madagascar. This infestation has dramatic consequences for local farmers as it alters drastically farmed algal growth and has caused farming activity to collapse in many places. The present study characterizes the structure and ultrastructure of the stages observed in the life cycle of Polysiphonia sp. and gives the results of a monitoring of 18 months made in three Kappaphycus alvarezii farming sites in the southwest of Madagascar. Transmission electron microscopy (TEM) was used to analyze the ultrastructure of the cortex in infested K. alvarezii. Five stages have been observed in the life cycle of Polysiphonia sp.: the infesting stage that is a small dark spot observed at the surface of K. alvarezii, the male gametophyte, the female gametophyte, the tetrasporocysts, and the undifferentiated stage where individuals show normal thalli without sexual differentiation. EFA infestation was never recorded in Sarodrano, but often in the two other monitored villages (Lambohara, Tampolove). Prevalence of infestation varied from 40 to 100 % and the rates of infestation from 42 to 78 epiphytes cm−2. Prevalence of infestation showed significant seasonal variation and a between-sites variation; the rates of infestation were not significantly different between sites and did not vary with the period. The ways of infestation between K. alvarezii individuals in an infested field and from infested to healthy fields are discussed at the light of the present results. [less ▲]

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See detailTrophic plasticity of Antarctic echinoids under contrasted environmental conditions
Michel, Loïc ULg; David, Bruno; Dubois, Philippe et al

in Polar Biology (2016), 39(5), 913-923

Echinoids are common members of Antarctic zoobenthos, and different groups can show important trophic diversity. As part of the ANT-XXIX/3 cruise of RV Polarstern, trophic plasticity of sea urchins was ... [more ▼]

Echinoids are common members of Antarctic zoobenthos, and different groups can show important trophic diversity. As part of the ANT-XXIX/3 cruise of RV Polarstern, trophic plasticity of sea urchins was studied in three neighbouring regions (Drake Passage, Bransfield Strait and Weddell Sea) featuring several depth-related habitats offering different trophic environments to benthic consumers. Three families with contrasting feeding habits (Cidaridae, Echinidae and Schizasteridae) were studied. Gut content examination and stable isotopes ratios of C and N suggest that each of the studied families showed a different response to variation in environmental and food conditions. Schizasteridae trophic plasticity was low, and these sea urchins were bulk sediment feeders relying on sediment-associated organic matter in all regions and/or depth-related habitats. Cidaridae consumed the most animal-derived material. Their diet varied according to the considered area, as sea urchins from Bransfield Strait relied mostly on living and/or dead animal material, while specimens from Weddell Sea fed on a mixture of dead animal material and other detritus. Echinidae also showed important trophic plasticity. They fed on various detrital items in Bransfield Strait, and selectivity of ingested material varied across depth-related habitats. In Weddell Sea, stable isotopes revealed that they mostly relied on highly 13C-enriched food items, presumably microbially-reworked benthic detritus. The differences in adaptive strategies could lead to family-specific responses of Antarctic echinoids to environmental and food-related changes. [less ▲]

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See detailUse of stable isotope ratios to delineate coastal benthic food web structure in Adélie Land (East Antarctica)
Michel, Loïc ULg; Dubois, Philippe; Eleaume, Marc et al

Poster (2016, April 29)

Antarctica currently undergoes strong and contrasted impacts linked with climate change. While the West Antarctic Peninsula is one of the most rapidly warming regions in the world, resulting in sea ice ... [more ▼]

Antarctica currently undergoes strong and contrasted impacts linked with climate change. While the West Antarctic Peninsula is one of the most rapidly warming regions in the world, resulting in sea ice cover decrease, in some parts of East Antarctica sea ice cover tends to increase, possibly in relation with changes in atmospheric circulation. Changes in sea ice cover are likely to influence benthic food web structure through modifications of benthic-pelagic coupling, disruption of benthic production and/or modifications of benthic community structure (i.e. resource availability for benthic consumers). Here, we studied shallow (0-20 m) benthic food web structure on the coasts of Petrels Island (Adélie Land, East Antarctica) during an event of unusually high spatial and temporal (two successive austral summers without seasonal break-up) sea ice cover. Using stable isotope ratios of C, N and S, we examined importance of several organic matter sources (benthic macroalgae, benthic biofilm, sympagic algae, suspended particulate organic matter and penguin guano) for nutrition of over 20 taxa of benthic invertebrates (sponges, sea anemones, nemerteans, sessile and mobile polychaetes, gastropods, bivalves, sipunculids, pycnogonids, amphipods, sea stars, sea urchins and sea cucumbers) spanning most present functional guilds. Our results provide insights about how Antarctic benthic consumers, which have evolved in an extremely stable environment, might adapt their feeding habits in response to sudden changes in environmental conditions and trophic resource availability. [less ▲]

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See detailImpacts of unusually high sea ice cover on Antarctic coastal benthic food web structure
Michel, Loïc ULg; Dubois, Philippe; Eleaume, Marc et al

Conference (2016, April 08)

Antarctica currently undergoes strong and contrasted impacts linked with climate change. While the West Antarctic Peninsula is one of the most rapidly warming regions in the world, resulting in sea ice ... [more ▼]

Antarctica currently undergoes strong and contrasted impacts linked with climate change. While the West Antarctic Peninsula is one of the most rapidly warming regions in the world, resulting in sea ice cover decrease, the sea ice cover of East Antarctica unexpectedly tends to increase, possibly in relation with changes in atmospheric circulation. Changes in sea ice cover are likely to influence benthic food web structure through modifications of benthic-pelagic coupling, disruption of benthic production and/or modifications of benthic community structure (i.e. resource availability for benthic consumers). Here, we studied shallow (0-20 m) benthic food web structure on the coasts of Petrels Island (Adélie Land, East Antarctica) during an event of unusually high spatial and temporal (two successive austral summers without seasonal break-up) sea ice cover. Using stable isotope ratios of C, N and S and the SIAR mixing model, we examined importance of several organic matter sources (benthic macroalgae, benthic biofilm, sympagic algae, suspended particulate organic matter and penguin guano) for nutrition of over 20 taxa of benthic invertebrates (sponges, sea anemones, nemerteans, sessile and mobile polychaetes, gastropods, bivalves, sipunculids, pycnogonids, amphipods, sea stars, sea urchins and sea cucumbers) spanning most present functional guilds. Our results provide insights about how Antarctic benthic consumers, which have evolved in an extremely stable environment, might adapt their feeding habits in response to sudden man-driven changes in environmental conditions and trophic resource availability. [less ▲]

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See detailCO2-blown microcellular non-isocyanate polyurethane (NIPU) foams: from bio- and CO2-sourced monomers to potentially thermal insulating materials
Grignard, Bruno ULg; Thomassin, Jean-Michel ULg; Gennen, Sandro ULg et al

in Green Chemistry (2016), 18(7), 2206-2215

Bio- and CO2-sourced non-isocyanate polyurethane (NIPU) microcellular foams were prepared using supercritical carbon dioxide (scCO2) foaming technology. These low-density foams offer low thermal ... [more ▼]

Bio- and CO2-sourced non-isocyanate polyurethane (NIPU) microcellular foams were prepared using supercritical carbon dioxide (scCO2) foaming technology. These low-density foams offer low thermal conductivity and have an impressive potential for use in insulating materials. They constitute attractive alternatives to conventional polyurethane foams. We investigated CO2’s ability to synthesize the cyclic carbonates that are used in the preparation of NIPU by melt step-growth polymerization with a bio-sourced amino-telechelic oligoamide and for NIPU foaming. Our study shows that CO2 is not only sequestered in the material for long-term application, but is also valorized as a blowing agent in the production of NIPU foams. Such foams will contribute to energy conservation and savings by reducing CO2 emissions. [less ▲]

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See detailNon-isocyanate polyurethanes from carbonated soybean oil Using monomeric or oligomeric diamines To achieve thermosets or thermoplastics
Poussard, Loïc; Mariage, J.; Grignard, Bruno ULg et al

in Macromolecules (2016), 49(6), 2162-2171

Fully bio- and CO2-sourced non-isocyanate polyurethanes (NIPUs) were synthesized by reaction of carbonated soybean oil (CSBO) either with biobased short diamines or amino-telechelic oligoamides derived ... [more ▼]

Fully bio- and CO2-sourced non-isocyanate polyurethanes (NIPUs) were synthesized by reaction of carbonated soybean oil (CSBO) either with biobased short diamines or amino-telechelic oligoamides derived from fatty acids to achieve respectively thermoset or thermoplastic NIPUs. Biobased carbonated vegetable oils were first obtained by metal-free coupling reactions of CO2 with epoxidized soybean oils under supercritical conditions (120 °C, 100 bar) before complete characterization by FTIR, 1H NMR, and electrospray ionization mass spectroscopy (ESI-MS). In a second step, biobased NIPUs were produced by melt-blending of the so-produced cyclocarbonated oil with the biobased aminated derivatives. The thermal and mechanical properties of resulting polymers were found to be depending on the cyclocarbonated vegetable oil/amine ratio. More precisely, short diamines and CSBO led to the formation of cross-linked NIPUs, and the resulting tensile and thermal properties were poor. In contrast, elastomeric NIPUs derived from oligoamides and CSBO exhibited a better rigidity, an improved elongation at break (εr up to 400%), and a higher thermal stability (T95 wt% > 350 °C) than those of starting oligoamides. These results are impressive and highlight the potentiality of this environmental friendly approach to prepare renewable NIPU materials of high performances. [less ▲]

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See detailTrophic plasticity of Antarctic echinoids under contrasted environmental conditions
Michel, Loïc ULg; David, Bruno; Dubois, Philippe et al

Poster (2016, February 12)

Echinoids are common members of Antarctic zoobenthos, and different groups can show important trophic diversity. As part of the ANT-XXIX/3 cruise of RV Polarstern, trophic plasticity of sea urchins was ... [more ▼]

Echinoids are common members of Antarctic zoobenthos, and different groups can show important trophic diversity. As part of the ANT-XXIX/3 cruise of RV Polarstern, trophic plasticity of sea urchins was studied in three neighbouring regions (Drake Passage, Bransfield Strait and Weddell Sea) featuring several depth-related habitats offering different trophic environments to benthic consumers. Three families with contrasting feeding habits (Cidaridae, Echinidae and Schizasteridae) were studied. Gut content examination and stable isotopes ratios of C and N suggest that each of the studied families showed a different response to variation in environmental and food conditions. Schizasteridae trophic plasticity was low, and these sea urchins were bulk sediment feeders relying on sediment-associated organic matter in all regions and/or depth-related habitats. Cidaridae consumed the most animal-derived material. Their diet varied according to the considered area, as sea urchins from Bransfield Strait relied mostly on living and/or dead animal material, while specimens from Weddell Sea fed on a mixture of dead animal material and other detritus. Echinidae also showed important trophic plasticity. They fed on various detrital items in Bransfield Strait, and selectivity of ingested material varied across depth-related habitats. In Weddell Sea, stable isotopes revealed that they mostly relied on highly 13C-enriched food items, presumably microbially-reworked benthic detritus. The differences in adaptive strategies could lead to family-specific responses of Antarctic echinoids to environmental and food-related changes. [less ▲]

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See detailPegylated Polyplexes Based On HDAC5 siRNA And Aliphatic Polycarbonate Polymers For An Anticancer Therapy
Frère, Antoine ULg; Baroni, Alexandra; Peulen, Olivier ULg et al

Poster (2015, November 23)

Detailed reference viewed: 14 (7 ULg)
See detailPolyplex Based on Polycarbonate Polymers for an Efficient Delivery of HDAC5 and HDAC7 siRNA
Frère, Antoine ULg; Tempelaar, Sarah; Peulen, Olivier ULg et al

Poster (2015, June 02)

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See detailImpact of the Structure of Biocompatible Aliphatic Polycarbonates on siRNA Transfection Ability
Frère, Antoine ULg; Kawalec, Michal; Tempelaar, Sarah et al

in Biomacromolecules (2015)

RNAi therapeutics are promising therapeutic tools that have sparked the interest of many researchers. In an effort to provide a safe alternative to PEI, we have designed a series of new guanidinium and/or ... [more ▼]

RNAi therapeutics are promising therapeutic tools that have sparked the interest of many researchers. In an effort to provide a safe alternative to PEI, we have designed a series of new guanidinium and/or morpholino functionalized biocompatible and biodegradable polycarbonate vectors. The impact of different functions (morpholino-, guanidinium-, hydrophobic groups), of the architecture (linear homopolymer to dumbbell-shape) and of the molecular weight of these copolymers on their capacity to form polyplexes and to decrease the expression of two epigenetic regulators of gene expression, HDAC7 and HDAC5 was evaluated. The use of one of these polymers combining morpholine and guanidine functions at the ratio >1 and hydrophobic trimethylene carbonate groups showed a significant decrease of mRNA and protein level in HeLa cells, similar to PEI. These results highlight the potential of polycarbonate vectors for future in vivo application as an anti-cancer therapy. [less ▲]

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See detailBlock, random and palm-tree amphiphilic fluorinated copolymers: controlled synthesis, surface activity and use as dispersion polymerization stabilizers
Alaimo, David ULg; Beigbeder, Alexandre; Dubois, Philippe et al

in Polymer Chemistry (2014), 5(18), 5273-5282

Detailed reference viewed: 79 (20 ULg)
See detailFeeding fluctuations in echinoids: from Weddell Sea to Bransfield Strait
De Ridder, Chantal; Michel, Loïc ULg; Lepoint, Gilles ULg et al

Conference (2014, September 09)

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See detailPolyplex based on polycarbonate polymesr for an efficient delivery of an anti-angiogenic siRNA
Frère, Antoine ULg; Tempelaar, Sarah; Peixoto, Paul ULg et al

Conference (2014, August 28)

Detailed reference viewed: 26 (12 ULg)
See detailImpact of the Structure of Biocompatible Aliphatic Polycarbonate on siRNA Transfection Ability
Frère, Antoine ULg; Kawalec, Michal; Tempelaar, Sarah et al

Poster (2014, May 26)

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See detailPolyplex Based On Polycarbonate Polymers For An Efficient Delivery Of An Anti-Angiogenic siRNA
Frère, Antoine ULg; Kawalec, Michal; Tempelaar, Sarah et al

Poster (2014)

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See detailThe intracellular fate of polycarbonate Polyplexes modulates the efficacy of siRNA
Frère, Antoine ULg; Kawalec, Michal; Peixoto, Paul ULg et al

Poster (2013, December)

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See detailEvaluation of a new biocompatible poly(N-(morpholino ethyl methacrylate)-based copolymer for the delivery of ruthenium oligonucleotides, targeting HPV16 E6 oncogene
Reschner, Anca ULg; Shim, Yong Ho; Dubois, Philippe et al

in Journal of Biomedical Nanotechnology (2013), 9

This study investigates the use of a new biocompatible block copolymer poly(2-(dimethylamino)ethyl methacrylate-N-(morpholino)ethyl methacrylate (PDMAEMA-b-PMEMA) for the delivery of a particular ... [more ▼]

This study investigates the use of a new biocompatible block copolymer poly(2-(dimethylamino)ethyl methacrylate-N-(morpholino)ethyl methacrylate (PDMAEMA-b-PMEMA) for the delivery of a particular antisense oligonucleotide targeting E6 gene from human papilloma virus. This antisense oligonucleotide was derivatized with a polyazaaromatic RuII complex which, under visible illumination, is able to produce an irreversible crosslink with the complementary targeted sequence. The purpose of this study is to determine whether by the use of a suitable transfection agent, it is possible to increase the efficiency of the antisense oligonucleotide targeting E6 gene, named Ru-P-4. In a recent study, we showed that Oligofectamine® transfected Ru-P-4 antisense oligonucleotide failed to inhibit efficiently the growth of cervical cancer cell line SiHa, contrarily to the Ru-P-6 antisense oligonucleotide, another sequence also targeting the E6 gene. The ability of PDMAEMA-b-PMEMA to form polyplexes with optimal physicochemical characteristics was investigated first. Then the ability of the PDMAEMA-b-PMEMA/Ru-P-4 antisense oligonucleotide polyplexes to transfect two keratinocyte cell lines (SiHa and HaCat) and the capacity of polyplexes to inhibit HPV16 + cervical cancer cell growth was evaluated. PDMAEMA-b-PMEMA base polyplexes at the optimal molar ratio of polymer nitrogen atoms to DNA phosphates (N/P), were able to deliver Ru-P-4 antisense oligonucleotide and to induce a higher growth inhibition in human cervical cancer SiHa cells, compared to other formulations based on Oligofectamine®. [less ▲]

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See detailCharacterization and transfection experiments of polyplexes targeting HDAC7
Frère, Antoine ULg; Kawalec, Michal; Collard, Laurence ULg et al

Poster (2012, October 22)

Detailed reference viewed: 38 (18 ULg)