Showing papers by "University of Rouen published in 2005"
TL;DR: It is shown that a chloroplast-located protein in higher plants takes an alternative route through the secretory pathway, and becomes N-glycosylated before entering the chlorop last.
Abstract: In contrast to animal and fungal cells, green plant cells contain one or multiple chloroplasts, the organelle(s) in which photosynthetic reactions take place. Chloroplasts are believed to have originated from an endosymbiotic event and contain DNA that codes for some of their proteins. Most chloroplast proteins are encoded by the nuclear genome and imported with the help of sorting signals that are intrinsic parts of the polypeptides. Here, we show that a chloroplast-located protein in higher plants takes an alternative route through the secretory pathway, and becomes N-glycosylated before entering the chloroplast.
358 citations
TL;DR: In this paper, the drivers of biodiversity conflicts are analysed in a European context for five habitat types: agricultural landscapes, forests, grasslands, uplands and freshwater habitats, with active stakeholder involvement at every stage of conflict identification and management as well as a range of other approaches including stakeholder dialogue and education, consumer education, improvement of political and legislative frameworks, financial incentives, and planning infrastructure.
Abstract: Conflicts between biodiversity conservation and human activities are becoming increasingly apparent in all European landscapes. The intensification of agricultural and silvicultural practices, land abandonment and other land uses such as recreation and hunting are all potential threats to biodiversity that can lead to conflicts between stakeholder livelihoods and biodiversity conservation. To address the global decline in biodiversity there is, therefore, a need to identify the drivers responsible for conflicts between human activities and the conservation of European biodiversity and to promote the management of these conflicts. Here, the drivers of biodiversity conflicts are analysed in a European context for five habitat types: agricultural landscapes, forests, grasslands, uplands and freshwater habitats. A multi- disciplinary approach to conflict management is described, with active stakeholder involvement at every stage of conflict identification and management as well as a range of other approaches including stakeholder dialogue and education, consumer education, improvement of political and legislative frameworks, financial incentives, and planning infrastructure.
288 citations
TL;DR: A large deviation theory is established for the space-time fluctuations of the empirical current for lattice gases in the macroscopic limit extending the dynamic approach for density fluctuations developed in previous articles.
Abstract: We study current fluctuations in lattice gases in the macroscopic limit extending the dynamic approach for density fluctuations developed in previous articles. More precisely, we establish a large deviation theory for the space-time fluctuations of the empirical current which include the previous results. We then estimate the probability of a fluctuation of the average current over a large time interval. It turns out that recent results by Bodineau and Derrida [Phys. Rev. Lett. 92, 180601 (2004)] in certain cases underestimate this probability due to the occurrence of dynamical phase transitions.
281 citations
TL;DR: Chiral ionic solvents were almost unexplored before the last five years as mentioned in this paper, and their applications in asymmetric synthesis, enzymatic chemistry, chiral chromatography and NMR are surveyed.
Abstract: Chiral ionic solvents were almost unexplored before the last five years. This field which is of increasing importance could constitute a renewal for the chemistry of chiral solvents. So far reported examples are designed either from the chiral pool (aminoacids, hydroxyacids, amines, aminoalcohols, terpenes and alkaloids) or by asymmetric synthesis; they can bear central, axial or planar chirality. Modern applications in asymmetric synthesis, enzymatic chemistry, chiral chromatography and NMR are surveyed. Their use in the field of liquid crystals and for stereoselective polymerisation are also discussed. At the end of the article, a series of tables is compiled including all the CILs described to date and their physical properties.
274 citations
TL;DR: This short review focuses on glycosylation and proteolytic processing of plant-made pharmaceuticals during their transport through the plant cell's secretory pathway and the practical implications of these important processes on the effectiveness of plant molecular pharming systems.
217 citations
TL;DR: To exploit fully the potential that plants offer for the production of therapeutic proteins for parenteral administration, it might be necessary to inhibit plant-specific post-translational modifications to obtain "humanized" non-immunogenic N-glycans on PMPs.
210 citations
TL;DR: In this paper, a filamentary composite elaborated by cold drawing was processed by High Pressure Torsion (HPT) and the nanostructure resulting from this severe plastic deformation (SPD) was investigated thanks to scanning electron microscopy and X-ray diffraction.
210 citations
TL;DR: It is shown that both the writer identification and the writer verification tasks can be carried out using local features such as graphemes extracted from the segmentation of cursive handwriting, making the approach general and very promising for large scale applications in the domain of handwritten document querying and writer verification.
208 citations
TL;DR: In this article, the volume fraction of nanometre size precipitates has been characterised in an Al-Zn-Mg alloy (AA7108.50) in two states of ageing.
200 citations
TL;DR: The results indicate that the neural responses to level of familiarity and emotional expression were observable at this early processing stage but without interacting, supporting the contention of parallel and independent processing of faces.
195 citations
TL;DR: In this article, a simulation of the continuous gaseous carrier phase and dilute-spray modelling is adopted for the discrete phase of spray combustion, which is performed in an Eulerian context and a Lagrangian description of the spray.
Abstract: Spray combustion is analysed using a full simulation of the continuous gaseous carrier phase, while dilute-spray modelling is adopted for the discrete phase. The direct numerical simulation of the flow is performed in an Eulerian context and a Lagrangian description is used for the spray. The numerous physical parameters controlling spray flames are first studied to construct two synthetic model problems of spray combustion: a laminar spray flame that propagates freely over a train of droplets and a weakly turbulent spray-jet with coflowing preheated air. It is observed that the flame structures can be classified with respect to three dimensionless quantities, which characterize the fuel/air equivalence ratio within the core of the spray-jet, the ratio between the mean distance between the droplets and the flame thickness, and the ratio between an evaporation time and a flame time. A large variety of reaction zone topologies is found when varying those parameters, and they are scrutinized by distinguishing between premixed and diffusion combustion regimes. Partially premixed combustion is observed in most of the spray-jet flames and the spray parameters that make the flame transition from non-premixed to premixed combustion are determined. A combustion diagram for dilute-spray combustion is then proposed from the identification of those various regimes.
TL;DR: In the Morris water maze, APP(695)SWE/co+PS1/DeltaE9 mice were impaired during acquisition of the hidden platform sub-task and the probe trial but not in the visible platform test, indicating a selective spatial deficit and disinhibitory tendencies in a mouse model with amyloid pathology.
TL;DR: In this article, an analysis of the water permeation and mechanical results has shown that plasma treatment improves fiber/matrix adhesion while autoclave treatment reduces water solubility in the fibers.
Abstract: In composite materials, fibers used as reinforcements are usually synthetic fibers such as glass. Since several years, for economic and environmental reasons, there has been an increasing interest in using plant fibers in composite systems. In this work, polyester composites reinforced by flax fibers submitted to helium cold plasma and/or autoclave treatments were investigated by means of water permeation measurements and mechanical tests. The analysis of the permeation and mechanical results has shown that plasma treatment improves fiber/matrix adhesion while autoclave treatment reduces water solubility in the fibers. For reinforced composites, therefore, autoclave treatment is more efficient in terms of water permeability and plasma treatment gives better stiffness in terms of mechanical properties. However, autoclave treatment followed by plasma treatment on flax fibers is recommended to obtain a good compromise for increasing both moisture resistance and stiffness of reinforced composites.
TL;DR: In this article, the authors identify past and current human-related threats potentially leading to conflicts in forests and focus on conflict management and monitoring, with an emphasis on inclusionary stakeholder networks and a range of approaches towards sustainable land use.
TL;DR: In this article, the solubility limit of copper in iron at temperature lower than 700°C is measured using thermoelectric power and small angle X-ray scattering.
Abstract: Measuring the solubility limit of copper in iron at temperature lower than 700°C is problematic because copper diffusion is too slow in this temperature range. To overcome this difficulty, fine precipitation of copper is studied. The solubility limit of copper is measured after complete precipitation using two complementary techniques: thermoelectric power and small angle X-ray scattering. Values obtained are confirmed by tomographic atom probe and give results much higher than what is usually extrapolated from high-temperature experiments.
01 Jan 2005
TL;DR: In this paper, the magnetic properties of FINEMET-type nanocrystalline alloys and isolated ferromagnetic AgCo nanoparticles are investigated both experimentally and numerically.
Abstract: The magnetic properties of FINEMET-type nanocrystalline alloys and isolated ferromagnetic AgCo nanoparticles are investigated both experimentally and numerically. Theoretical models of spins that simulate ideal nanocrystalline alloys and isolated nanoparticles are considered while their magnetic properties are derived from Monte Carlo simulation of low-temperature spin ordering. Interesting features such as magnetic polarization of the matrix due to penetrating fields arising from nanograins and the role played by the crystalline fraction in the overall magnetic behaviour, in the case of nanocrystalline alloys are investigated. For isolated nanoparticles it is shown that the competition between surface and bulk anisotropy gives rise to surface spin disorder that, together with finite-size effects, is responsible for the experimentally observed lack of saturation of the magnetization in high applied fields. These simulation results are confirmed by experimental data obtained on FINEMET nanocrystalline alloys and isolated ferromagnetic AgCo colloidal nanoparticles.
TL;DR: No specific imipenem binding site was found in CarO, and this protein would rather form unspecific monomeric channels than form channels, despite its suggested porin function.
Abstract: It has been recently shown that resistance to both imipenem and meropenem in multidrug-resistant clinical strains of Acinetobacter baumannii is associated with the loss of a heat-modifiable 25/29-kDa outer membrane protein, called CarO. This study aimed to investigate the channel-forming properties of CarO. Mass spectrometry analyses of this protein band detected another 25-kDa protein (called Omp25), together with CarO. Both proteins presented similar physicochemical parameters (M(w) and pI). We overproduced and purified the two polypeptides as His-tagged recombinant proteins. Circular dichroism analyses demonstrated that the secondary structure of these proteins was mainly a beta-strand conformation with spectra typical of porins. We studied the channel-forming properties of proteins by reconstitution into artificial lipid bilayers. In these conditions, CarO induced ion channels with a conductance value of 110 pS in 1 M KCl, whereas the Omp25 protein did not form any channels, despite its suggested porin function. The pores formed by CarO showed a slight cationic selectivity and no voltage closure. No specific imipenem binding site was found in CarO, and this protein would rather form unspecific monomeric channels.
TL;DR: Despite the neurologic signs, APP23 transgenic mice were not deficient in stationary beam, coat-hanger, and rotorod tests, indicating intact motor coordination abilities.
TL;DR: It is suggested that day 14 of pregnancy is a hyposensitive period to stressful agents due to an important plasticity of the developing gross nervous structures.
TL;DR: The present study provides the first demonstration of primary adrenal Cushing's syndrome dependent on both gonadotropin and gastric inhibitory polypeptide and shows a hyperresponsiveness of hyperplastic adrenal tissues to 5-HT, angiotensin II, and AVP.
Abstract: In ACTH-independent macronodular adrenal hyperplasia (AIMAH) causing Cushing's syndrome, cortisol production can be controlled by illegitimate membrane receptors. The aim of the present study was to evaluate in vivo and in vitro the sensitivity of AIMAH to various regulatory factors to detect the expression of illegitimate receptors by the tissues. Four consecutive patients with AIMAH and hypercortisolism (H1-H4) preoperatively underwent a series of pharmacological and/or physiological tests. After adrenalectomy, in vitro studies were conducted to investigate the cortisol responses of cultured cells, derived from hyperplastic tissues, to various membrane receptor ligands. The adrenal tissues of the two patients who responded in vivo to food intake (H2 and H4) were stimulated in vitro by gastric inhibitory polypeptide. GnRH and human chorionic gonadotropin, but not FSH, stimulated cortisol secretion in patients H2 and H4. In these two cases, human chorionic gonadotropin but not GnRH stimulated cortisol production from cultured adrenocortical cells. Cisapride induced a significant increase in cortisol levels in patient H1. In addition, serotonin (5-HT) was more efficient to stimulate cortisol production in H1 cells than in normal adrenocortical cells. Upright stimulation test provoked an increase in cortisol levels in patients H1, H2, and H3. H1 and H2 cells were more sensitive to the stimulatory action of angiotensin II than normal cells. Similarly, arginine vasopressin (AVP) more efficiently activated steroidogenesis in H1 cells than in normal cells. In H1 tissue, immunohistochemical studies revealed the presence of 5-HT- and AVP-like immunoreactivities within clusters of steroidogenic cells, suggesting that these two factors acted through an autocrine/paracrine mechanism to stimulate cortisol secretion. The present study provides the first demonstration of primary adrenal Cushing's syndrome dependent on both gonadotropin and gastric inhibitory polypeptide. Our data also show a hyperresponsiveness of hyperplastic adrenal tissues to 5-HT, angiotensin II, and AVP. Finally, they reveal for the first time the presence of paracrine regulatory signals in adrenal hyperplasia tissues.
TL;DR: In this article, a class of Stefan-type problems with a convection term and a pseudomonotone nonlinear diffusion operator is considered and the authors prove existence, uniqueness and stability in the framework of renormalized solutions.
TL;DR: By determining the dominant arm and the preferential breathing side, the coach can obtain a swimmer profile that allows both coach and swimmer to better understand and respond to excessive coordination asymmetry.
TL;DR: The heterogeneity of the purified water-soluble neutral fraction coming from the mucilage extract of the yellow flaxseed was investigated, and the molecular weight analysis acquired by multi-angle laser light scattered revealed the association of two high M(w) polymers.
TL;DR: In this paper, the authors introduce a statistical mechanical formalism for the study of discrete-time stochastic processes with which they prove: (i) general properties of extremal chains, including triviality on the tail σ-algebra, short-range correlations, realization via infinite-volume limits and ergodicity.
Abstract: We introduce a statistical mechanical formalism for the study of discrete-time stochastic processes with which we prove: (i) General properties of extremal chains, including triviality on the tail σ-algebra, short-range correlations, realization via infinite-volume limits and ergodicity. (ii) Two new sufficient conditions for the uniqueness of the consistent chain. The first one is a transcription of a criterion due to Georgii for one-dimensional Gibbs measures, and the second one corresponds to the Dobrushin’s criterion in statistical mechanics. (iii) Results on loss of memory and mixing properties for chains in the Dobrushin regime. These results are complementary to those existing in the literature, and generalize the Markovian results based on the Dobrushin ergodic coefficient.
TL;DR: The analyses of the outer membrane from different A. baumannii strains indicated a modification in the expression of two proteins of 29 and 43 kDa, respectively, which were identified as a protein belonging to the OprD family, a basic amino acid and imipenem porin.
Abstract: With the increased number of resistant Acinetobacter baumannii strains, it is urgently required to decipher the molecular bases of outer membrane permeability. The analyses of the outer membrane from different A. baumannii strains indicated a modification in the expression of two proteins of 29 and 43 kDa, respectively. By electrophoresis and MALDI-MS analyses, the 43 kDa OMP was identified as a protein belonging to the OprD family, a basic amino acid and imipenem porin.
TL;DR: In this paper, the degradation of flax fibres is explained by the creation of damages within the fibre and by the modification of the chemical composition of the matrix components, which is due to the evolution of the components ensuring the transfer of load between the microfibrils and thus conditioning the strength of the cellular wall.
Abstract: The complex structure of flax fibres involves many chemical biomolecules located in an amorphous matrix in which cellulose micrifibrils are embbeded. The drying of flax fibres influences significantly their tensile strength. This result can be explained by the creation of damages within the fibre and by the modification of the chemical composition of the matrix components. This loss of water involves a modification of the adhesion between the cellulose microfibrils and the matrix. This modification is due to the evolution of the components ensuring the transfer of load between the microfibrils and thus conditioning the strength of the cellular wall.
TL;DR: Selective inhibitors were identified for several of the activities tested, leaving some potential for design of improved inhibitors, however, all tested compounds exhibited cellular toxicity that presently limits their applications.
Abstract: Human immunodeficiency virus type I reverse transcriptase (RT) possesses distinct DNA polymerase and RNase H sites, whereas integrase (IN) uses the same active site to perform 3'-end processing and strand transfer of the proviral DNA. These four enzymatic activities are essential for viral replication and require metal ions. Two Mg2+ ions are present in the RT polymerase site, and one or two Mg2+ ions are required for the catalytic activities of RNase H and IN. We tested the possibility of inhibition of the RT polymerase and RNase H as well as the IN 3'-end processing and transfer activities of purified enzymes by a series of 3,7-dihydroxytropolones designed to target two Mg2+ ions separated by approximately 3.7 angstroms. The RT polymerase and IN 3' processing and strand transfer activities were inhibited at submicromolar concentrations, while the RNase H activity was inhibited in the low micromolar range. In all cases, the lack of inhibition by tropolones and O-methylated 3,7-dihydroxytropolones was consistent with the active molecules binding the metal ions in the active site. In addition, inhibition of the DNA polymerase activity was shown to depend on the Mg2+ concentration. Furthermore, selective inhibitors were identified for several of the activities tested, leaving some potential for design of improved inhibitors. However, all tested compounds exhibited cellular toxicity that presently limits their applications.
TL;DR: For the first time, differences in enzyme typology between biogenic structures collected on the same site but produced by different organisms are evaluated and suggested species dependent pathways for the decomposition of organic matter.
Abstract: Soil-engineering organisms (earthworms, termites and ants) affect the soil and litter environment indirectly by the accumulation of their biogenic structures (casts, pellets, galleries, crop sheetings nests…). An enzymatic typology was conducted on six types of biogenic structures: casts produced by two earthworms ( Andiodrilus sp. and Martiodrilus sp.), a nest built by a soil-feeding termite ( Spinitermes sp.), crop galleries built by another soil-feeding termite ( Ruptitermes sp.) and soil pellets produced by two species of leaf-cutting ant ( Acromyrmex landolti and Atta laevigata ) and an control soil from a natural Colombian savanna. A total of 10 enzymes (xylanase, amylase, cellulase, α-glucosidase, β-glucosidase, β-xylosidase, N -acteyl-glucosaminidase, alkaline and acid phosphatases and laccase) were selected to characterize the functional diversity of the biogenic structures. Our results showed that (i) Martiodrilus casts were characterized by a broad enzymatic profile that was different from that of the soil. (ii) A. laevigata pellets and termite structures had a profile broadly similar to the soil only with some enzymes (iii) Andiodrilus casts had an enzyme profile very similar to that of the soil. These results suggest that the functional diversity of these structures is related to differences between species and not to differences between taxonomic groups. For the first time, we evaluated differences in enzyme typology between biogenic structures collected on the same site but produced by different organisms. These differences suggested species dependent pathways for the decomposition of organic matter.
TL;DR: The results suggest that NIRS spectra might be used as ‘fingerprints’ to identify organisms responsible for soil aggregate production and the ordination given by the co-inertia analysis is proposed as a basis for a functional classification of soil engineers.
Abstract: Summary
1
The aim of this study was to search for specific signatures of biogenic structures (i.e. earthworm casts, termite sheathings and mound material, and ant deposits) made by 15 species of soil engineers in a Colombian savanna. We thus investigated the organic matter (OM) biochemical composition of biostructures using near infrared spectroscopy (NIRS) and its relationship with selected biological (respirometry) and chemical attributes.
2
We found significant differences in OM quality and potential respiration rate among biostructures. These results were attributed to production patterns of biostructures and invertebrate feeding behaviour. A multiple co-inertia analysis was performed with NIRS, respirometry and chemical results. It separated (i) carton termite mounds, (ii) earthworm casts and organo-mineral termite mounds and (iii) termite sheathings and ant deposits.
3
These results suggest that NIRS spectra might be used as ‘fingerprints’ to identify organisms responsible for soil aggregate production. Moreover, the ordination given by the co-inertia analysis is proposed as a basis for a functional classification of soil engineers, assuming that different biostructure properties imply different effects on soil functioning.
TL;DR: The authors reviewed the peopling of the Dogon Country (Mali) and surrounding regions over the past 3000 years, taking into account the influence of Sahelian paleoclimatic variations as well as archaeological, ethnoarchaeological, and historical data.