Philippe JEAN-PIERRE

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• Type de publi. : Article dans une revue
• Date de publi. : 01/01/2007
• Auteurs : Maryse DelaportePhilippe SoudantChristophe LambertMarine JegadenJeanne MoalStéphane PouvreauLionel DégremontPierre BoudryJean-François Samain
• Organismes : Laboratoire de Physiologie des Invertébrés Laboratoire des Sciences de l'Environnement Marin (LEMAR) Laboratoire des Sciences de l'Environnement Marin (LEMAR) Laboratoire des Sciences de l'Environnement Marin (LEMAR) Laboratoire de Physiologie des Invertébrés Laboratoire de Physiologie des Invertébrés Unité Amélioration génétique, Santé animale et Environnement Unité Amélioration génétique, Santé animale et Environnement Laboratoire de Physiologie des Invertébrés
• Publié dans Journal of Experimental Marine Biology and Ecology le 01/11/2020

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Résumé : Within the framework of a national scientific program named "MORtalités ESTivales de l'huître creuse Crassostrea gigas" (MOREST), a family-based experiment was developed to study the genetic basis of resistance to summer mortality in the Pacific oyster, Crassostrea gigas. As part of the MOREST project, the second generation of three resistant families and two susceptible families were chosen and pooled into two respective groups: "R" and "S". These two groups of oysters were conditioned for 6 months on two food levels (4% and 12% of oyster soft-tissue dry weight in algal dry weight per day) with a temperature gradient that mimicked the Marennes-Oléron natural cycle during the oyster reproductive period. Oyster mortality remained low for the first two months, but then rapidly increased in July when seawater temperature reached 19 °C and above. Mortality was higher in "S" oysters than in "R" oysters, and also higher in oysters fed the 12% diet than those fed 4%, resulting in a decreasing, relative order in cumulative mortality as follows; 12% "S" > 12% "R" > 4% "S" > 4% "R". Although the observed mortality rates were lower than those previously observed in the field, the mortality differential between "R" and "S" oysters was similar. Gonadal development, estimated by tissue lipid content, followed a relative order yielding a direct, positive relationship between reproductive effort and mortality as we reported precedently by quantitative histology. Regarding hemocyte parameters, one of the most striking observations was that reactive oxygen species (ROS) production was significantly higher in "S" oysters than in "R" oysters in May and June, regardless of food level. The absence of known environmental stress under these experimental conditions suggests that the ROS increase in "S" oyster could be related to their higher reproductive activity. Finally, a higher increase in hyalinocyte counts was observed for"S" oysters, compared to "R" oysters, in July, just before mortality. Taken together, our results suggest an association of genetically based resistance to summer mortality, reproductive strategy and hemocyte parameters.

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• Type de publi. : Article dans une revue
• Date de publi. : 01/01/2007
• Auteurs : Thomas RobertPhilippe BeillasAlain MaupasJean-Pierre Verriest
• Organismes : Laboratoire de Biomécanique et Mécanique des Chocs Laboratoire de Biomécanique et Mécanique des Chocs Laboratoire de Biomécanique et Mécanique des Chocs Laboratoire de Biomécanique et Mécanique des Chocs
• Publié dans International Journal of Crashworthiness le 31/10/2020

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Résumé : Standing passenger safety is currently a major challenge for the development of public transportation. One of the current difficulties to overcome this problem is the lack of knowledge about the motion of passengers following a minor incident, such as an emergency braking or a slight collision. This study brings new experimental data about the head kinematics of volunteers in situations representative of typical public transportation incidents. Two levels of perturbation were tested - an emergency braking and a minor collision, combined with three initial postures - freestanding, using a backrest, and holding a vertical bar. Data were obtained for (1) the three-dimensional head trajectories; (2) the maximal excursions of the head along the longitudinal axis; and (3) corridors of the head tangential velocity versus its longitudinal displacement. Even though there are limitations, these data can be used as a first estimate to predict the risks of impact between the head of passengers and their surrounding environment. They also provide insight into the impact velocity of this eventual collision. Furthermore, they highlight the influence of the level of perturbation and of the restraint device possibly used. These data are mainly intended to be used by designers of public transportation vehicles to improve the future interior layouts with regard to the standing passenger safety.

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Fichiers liés : robert_2007_ijc_p.pdf

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• Type de publi. : Article dans une revue
• Date de publi. : 01/01/2007
• Auteurs : Isabelle MortierMarion VeltenPauline DupaigneNicolas N. MirouzeOlivier PiétrementStephen McgovernGwennaële FichantBernard MartinPhilippe NoirotEric Le CamPatrice PolardJean-Pierre Claverys
• Organismes : Laboratoire de microbiologie et génétique moléculaires - UMR5100 Unité de recherche Génétique Microbienne Signalisation, noyaux et innovations en cancérologie MICrobiologie de l'ALImentation au Service de la Santé Signalisation, noyaux et innovations en cancérologie Unité de recherche Génétique Microbienne Laboratoire de microbiologie et génétique moléculaires - UMR5100 Laboratoire de microbiologie et génétique moléculaires - UMR5100 Unité de recherche Génétique Microbienne Institut Gustave Roussy Institut National de Recherche Agronomique, Unité de Génetique Microbienne & Environm Laboratoire de microbiologie et génétique moléculaires - UMR5100
• Publié dans Cell le 28/10/2020

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Résumé : Natural transformation is a mechanism for genetic exchange in many bacterial genera. It proceeds through the uptake of exogenous DNA and subsequent homology-dependent integration into the genome. In Streptococcus pneumoniae, this integration requires the ubiquitous recombinase, RecA, and DprA, a protein of unknown function widely conserved in bacteria. To unravel the role of DprA, we have studied the properties of the purified S. pneumoniae protein and its Bacillus subtilis ortholog (Smf). We report that DprA and Smf bind cooperatively to single-stranded DNA (ssDNA) and that these proteins both self-interact and interact with RecA. We demonstrate that DprA-RecA-ssDNA filaments are produced and that these filaments catalyze the homology-dependent formation of joint molecules. Finally, we show that while the Escherichia coli ssDNA-binding protein SSB limits access of RecA to ssDNA, DprA lowers this barrier. We propose that DprA is a new member of the recombination-mediator protein family, dedicated to natural bacterial transformation.

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• Type de publi. : Communication dans un congrès
• Date de publi. : 01/01/2007
• Auteurs : Philippe BolonEmmanuel TrouvéIvan PétillotGabriel VasileMichel GayLionel BombrunJean-Marie NicolasFlorence TupinTania LandesMathieu KoehlP. Grussenmeyer
• Organismes : Laboratoire d'Informatique, Systèmes, Traitement de l'Information et de la Connaissance Laboratoire d'Informatique, Systèmes, Traitement de l'Information et de la Connaissance Laboratoire d'Informatique, Systèmes, Traitement de l'Information et de la Connaissance Laboratoire d'Informatique, Systèmes, Traitement de l'Information et de la Connaissance GIPSA-Services GIPSA - Signal Images Physique GIPSA - Signal Images Physique Télécom ParisTech Télécom ParisTech Modèles et simulation pour l'architecture, l'urbanisme et le paysage Modèles et simulation pour l'architecture, l'urbanisme et le paysage Modèles et simulation pour l'architecture, l'urbanisme et le paysage

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Résumé : The monitoring of temperate glacier activity is one of the applications which require the combined use of optical and SAR data. It should become feasible thanks to the ALOS PRISM and PALSAR sensors. In this paper, we present the interest of using L-band polarimetric interferometric SAR data and high resolution panchromatic stereoscopic data to monitor moving temperate glaciers made of ice, snow and rocks. The scientific issues are described and a test-site located in the Mont-Blanc region in the Alps is proposed for specific experiment and validation. The Mont-Blanc test-site includes two well-known glaciers (Mer-de-Glace and Argentière glaciers) where a large data set has been collected: ERS, RADARSAT and ENVISAT data, airborne E-SAR data (X, C, L and P bands), airborne photographs, GPS and GPR in-situ measurements...

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Fichiers liés : Bolon_Kyoto2007_LSI01.pdf

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• Type de publi. : Article dans une revue
• Date de publi. : 01/01/2007
• Auteurs : Beatrice Pallot-PradesLaurent GrangePhilippe GaudinChristian AlexandrePierre Miossec
• Organismes : Contraintes mécaniques et tissu osseux Groupe de Recherche et d’Étude du Processus Inflammatoire Groupe de Recherche et d’Étude du Processus Inflammatoire Contraintes mécaniques et tissu osseux Service d'immunologie et rhumatologie
• Publié dans Arthritis Research and Therapy le 27/10/2020

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Résumé : The goal of the present study was to record changes in bone mineral density (BMD) and markers of bone turnover in patients with rheumatoid arthritis (RA) who were treated with methotrexate combined (or not combined) with infliximab. Included were 90 patients with RA who required anti-TNF-alpha therapy with infliximab because of persistent active disease despite treatment with methotrexate. The historical control group included 99 patients with RA who were treated with methotrexate at a time when anti-TNF-alpha treatment was not yet available. Lumbar and femoral neck BMD was measured using dual energy X-ray absorptiometry at baseline and 1 year later. Osteocalcin, C-terminal cross-linked telopeptide of type I collagen, parathyroid hormone and 25-hydroxycholecalciferol were measured in plasma at baseline and 1 year later. At 1 year BMD had decreased in the control group at spine (P < 0.01) and femoral neck (P < 0.001). In contrast, BMD at spine and femoral neck did not change after 1 year of infliximab treatment. At the same time point, no change in bone remodelling markers was observed. No association was observed between clinical response and changes in BMD, indicating that even those who did not respond clinically did not lose bone over a 1-year period. These data confirm the BMD decrease observed in RA patients treated with methotrexate alone. This bone loss was prevented by infliximab therapy. Importantly, this beneficial effect was also observed in apparent nonresponders.

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• Type de publi. : Chapître d'ouvrage
• Date de publi. : 01/01/2007
• Auteurs : Jean Baptiste TraversacMagali AubertJean-Pierre LaportePhilippe Perrier-Cornet
• Organismes : Sciences pour l'Action et le Développement : Activités, Produits, Territoires Marchés, Organisations, Institutions et Stratégies d'Acteurs Marchés, Organisations, Institutions et Stratégies d'Acteurs Marchés, Organisations, Institutions et Stratégies d'Acteurs

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Résumé : Dans un contexte de fortes incertitudes sur les marchés, de surproduction sur certains d'entre eux et, plus généralement, d'interrogations sur le positionnement concurrentiel du secteur viticole national, ce chapitre fait le point sur l'ensemble des évolutions structurelles de la viticulture française, à partir des statistiques des recensements et enquêtes du SCEES portant sur l'ensemble des exploitations viticoles sur la période 1998-2005. Les évolutions structurelles de la viticulture française ces dernières années confirment les grandes tendances observées depuis un quart de siècle. Le nombre des exploitations diminue, le vignoble se concentre et les exploitations se spécialisent. Le travail salarié et l'intégration de fonctions aval par les producteurs s'affirment comme un trait distinctif du secteur. La viticulture se distingue aussi par des processus de renouvellement particulier laissant une place plus large à de nouveaux entrants, qui bien que n'étant pas originaires du secteur, y investissent des capitaux et des savoir-faire. La synthèse de ces différents processus, par ailleurs largement contrastés selon les régions, conduit à quelques réflexions sur les orientations de l'intervention publique dans le secteur, en regard des mutations actuelles.

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• Type de publi. : Article dans une revue
• Date de publi. : 01/01/2007
• Auteurs : Sonia ZineJacqueline BoutinPhilippe WaldteufelJean-Luc VergelyThierry PellarinPascal Lazure
• Organismes : Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques Service d'aéronomie Service d'aéronomie Laboratoire d'étude des transferts en hydrologie et environnement Direction de l'Environnement et de l'Aménagement Littoral
• Publié dans IEEE Transactions on Geoscience and Remote Sensing le 31/10/2020

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Résumé : This paper aims at studying the quality of the sea surface salinity (SSS) retrieved from soil moisture and ocean salinity (SMOS) data in coastal areas. These areas are characterized by strong and variable SSS gradients [several practical salinity units (psu)] on relatively small scales: the extent of river plumes is highly variable, typically at kilometric and daily scales. Monitoring this variability from SMOS measurements is particularly challenging because of their resolution (typically 30-100 km) and because of the contamination by the nearby land. A set of academic tests was conducted with a linear coastline and constant geophysical parameters, and more realistic tests were conducted over the Bay of Biscay. The bias of the retrieved SSS has been analyzed, as well as the root mean square (rms) of the bias, and the retrieved SSS compared to a numerical hydrodynamic model in the semirealistic case. The academic study showed that the Blackman apodization window provides the best compromise in terms of magnitude and fluctuations of the bias of the retrieved SSS. Whatever the type of vegetation cover, a strong negative bias, greater than 1 psu, was found when nearer than 36 km from the coast. Between 44 and 80 km, the type of vegetation cover has an impact of less than a factor 2 on the bias, and no influence further than 80 km from the coast. The semirealistic study conducted in the Bay of Biscay showed a bias over ten days lower than 0.2 psu for distances greater than 47 km, due to an averaging over various geometries (coastline orientation, swath orientation, etc.). The bias showed a weak dependence on the location of the grid point within the swath. Despite the noise on the retrieved SSS, contrasts due to the plume of the Loire River and the Gironde estuary remained detectable on ten-day averaged maps with an rms of 0.57 psu. Finally, imposing thresholds on the major axis of the measurements brought little improvement to the bias, whereas it increased the rms and- could lead to strong swath restriction: a 49-km threshold on the major axis resulted in an effective swath of 800-900 km instead of 1200 km.

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• Type de publi. : Article dans une revue
• Date de publi. : 01/01/2007
• Auteurs : Jean-Louis DurandThierry BariacMarc GhesquièrePhilippe BironPatricia RichardM. HumphreysZ. Zwierzykovski
• Organismes : Unité de recherche d'Écophysiologie des Plantes Fourragères Biogéochimie et écologie des milieux continentaux Unité de recherche Génétique et Amélioration des Plantes Fourragères Biogéochimie et écologie des milieux continentaux Biogéochimie et écologie des milieux continentaux Institute for Genetic and Environment Research Institute of Plant Genetics
• Publié dans Environmental and Experimental Botany le 24/10/2020

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Résumé : The depth of water extraction is a key trait in grassland species. For comparing individual plant forms in the field, different ecological studies have proven the efficiency of the isotopic signal of water (5180). To date, there has been no assessment of the aforementioned method within closely related grasslands species. For this study, Festuca arundinacea and Lolium multiflorum plants were grown in nutrient solution and the delta O-18 of different plant compartments were compared to the delta O-18 of the solution under both high and low transpiration conditions. In both species, the basal part of the tillers, excluding the eldest sheath, closely reflected the isotopic water composition of the nutrient solution, whereas other parts of the plant exhibited a significant enrichment in O-18 as a consequence of transpiration. In a second experiment, using the genetic variability within plants obtained from crossing E arundinacea with Lolium multiflorum, the study explored the variability of the depth of water extraction and delta O-18 under conditions of soil water deficit. A plant nursery of hybrids was established in a greenhouse with plants sewn directly in the soil. Ten neutron probe access tubes were placed close to ten individual plants, which were sampled twice at 38 day intervals, following a period of 14 and 52 days of water deprivation. On these same dates, soil samples were extracted down to 1 meter in the vicinity of the 10 studied plants. Water was fully extracted from both plant and soil samples and the isotopic composition was measured. The predawn leaf water potential exhibited large variations in water status among the ten plants studied. The measured plant delta O-18 were similar to the values computed from estimated soil water extraction profiles (using neutron probe measurements) and soil delta O-18 of the soil water profile. On the second date of sampling, the delta O-18 and leaf water potentials of three individual plants (L. multiflorum) were observed throughout the day, revealing a gradual decrease in 180 content as the plant water potential decreased. The role of short term changes in the soil-root hydraulic conductance on depth of water extraction is discussed in this study. (c) 2006 Elsevier B.V. All rights reserved.

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• Type de publi. : Chapître d'ouvrage
• Date de publi. : 01/01/2007
• Auteurs : Patrick WagnonJean-Emmanuel SicartL. MaisinchoBernard FrancouPatrick GinotJean-Philippe ChazarinVincent FavierPierre Ribstein
• Organismes : Laboratoire de glaciologie et géophysique de l'environnement Unité de Recherche Great Ice Unité de Recherche Great Ice Unité de Recherche Great Ice Unité de Recherche Great Ice Laboratoire de glaciologie et géophysique de l'environnement

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• Type de publi. : Article dans une revue
• Date de publi. : 01/01/2007
• Auteurs : Jean-Louis DurandThierry BariacMarc GhesquièrePhilippe BironPatricia RichardM. HumphreysZ. Zwierzykovski
• Organismes : Unité de recherche d'Écophysiologie des Plantes Fourragères Biogéochimie et écologie des milieux continentaux Unité de recherche Génétique et Amélioration des Plantes Fourragères Biogéochimie et écologie des milieux continentaux Biogéochimie et écologie des milieux continentaux Institute for Genetic and Environment Research Institute of Plant Genetics
• Publié dans Environmental and Experimental Botany le 24/10/2020

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Résumé : The depth of water extraction is a key trait in grassland species. For comparing individual plant forms in the field, different ecological studies have proven the efficiency of the isotopic signal of water (δ18O). To date, there has been no assessment of the aforementioned method within closely related grasslands species. For this study, Festuca arundinacea and Lolium multiflorum plants were grown in nutrient solution and the δ18O of different plant compartments were compared to the δ18O of the solution under both high and low transpiration conditions. In both species, the basal part of the tillers, excluding the eldest sheath, closely reflected the isotopic water composition of the nutrient solution, whereas other parts of the plant exhibited a significant enrichment in 18O as a consequence of transpiration. In a second experiment, using the genetic variability within plants obtained from crossing F. arundinacea with Lolium multiflorum, the study explored the variability of the depth of water extraction and δ18O under conditions of soil water deficit. A plant nursery of hybrids was established in a greenhouse with plants sewn directly in the soil. Ten neutron probe access tubes were placed close to ten individual plants, which were sampled twice at 38 day intervals, following a period of 14 and 52 days of water deprivation. On these same dates, soil samples were extracted down to 1 meter in the vicinity of the 10 studied plants. Water was fully extracted from both plant and soil samples and the isotopic composition was measured. The predawn leaf water potential exhibited large variations in water status among the ten plants studied. The measured plant δ18O were similar to the values computed from estimated soil water extraction profiles (using neutron probe measurements) and soil δ18O of the soil water profile. On the second date of sampling, the δ18O and leaf water potentials of three individual plants (L. multiflorum) were observed throughout the day, revealing a gradual decrease in 18O content as the plant water potential decreased. The role of short term changes in the soil–root hydraulic conductance on depth of water extraction is discussed in this study.

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