Résumé
Lors des dernières élections françaises de 2004, la question de la place et du rôle des candidats d’origine maghrébine a été un enjeu controversé, relançant le débat sur le modèle ...universaliste français. Dans ce contexte, nous nous sommes interrogée sur l’importance accordée à l’ethnicité par les candidats d’origine maghrébine dans leur discours, à travers l’étude de leurs professions de foi et la réalisation d’entretiens. Trois types d’attitudes envers l’ethnicité ont ainsi été observés. Si la majorité des candidats ne mentionne aucun élément d’ordre ethnique, certains l’utilisent ponctuellement – soit pour se présenter, soit pour désigner une partie de la population française – tandis que seule une force autonome marginale (Union française pour la cohésion nationale - UFCN) fait de la situation des gens d’origine maghrébine une de ses préoccupations centrales.
Cet article se propose de comprendre l’utilisation qu’ont faite du mot démocratie et de ses dérivés les candidats aux élections législatives de 2002 et cantonales de 2004 en France, à partir de leurs ...professions de foi. L’analyse révèle des variations importantes dans l’usage des termes en fonction à la fois du contexte de l’élection, de l’appartenance politique et du tour de scrutin.
Background and aims: The prevalence and severity of liver steatosis are higher in patients infected with genotype 3 hepatitis C virus (HCV) than in patients infected with other genotypes. HCV core ...protein is known to affect lipid metabolism, inducing lipid droplet accumulation both in vitro and in vivo. We used an in vitro cellular model to investigate whether an HCV core protein with residues specific to genotype 3 increased this phenomenon. Methods: Sequence comparisons for HCV core protein domain II, which is known to interact with lipid droplets, identified the phenylalanine (F) residue at position 164 as the only residue specific to genotype 3. We compared the area covered by lipid droplets in sections of cells producing a wild-type genotype 1a HCV core protein with that in cells producing a Y164F mutant protein. Results: Cumulative lipid droplet area was significantly greater in sections of cells producing the Y164F mutant HCV core protein than in cells producing the wild-type protein (p<0.001). The frequency of cell sections containing more than 3 μm2 of lipid droplets, in particular, was higher for the mutant than for the wild-type protein. Conclusion: Our data provide a molecular explanation for HCV genotype 3-specific lipid accumulation. This difference between genotypes may be due to phenylalanine having a higher affinity for lipids than tyrosine (Y). These observations provide useful information for further studies of the mechanisms involved in HCV-induced steatosis.
Spermatogenesis is a complex process involving cell proliferation, differentiation and apoptosis. Fibroblast Growth Factor 2 (FGF-2) is involved in testicular function, but its role in ...spermatogenesis has not been fully documented. The control of FGF-2 expression particularly occurs at the translational level, by an internal ribosome entry site (IRES)-dependent mechanism driving the use of alternative initiation codons. To study IRES activity regulation in vivo, we have developed transgenic mice expressing a bicistronic construct coding for two luciferase genes. Here we show that the FGF-2 IRES is age-dependently activated in mouse testis, whereas EMCV or c-myc IRESs are not. Real time PCR confirms that this regulation is translational. By using immunohistological techniques, we demonstrate that FGF-2 IRES stimulation occurs in adult, but not in immature, type-A spermatogonias.This is correlated with activation of endogenous FGF-2 expression in spermatogonia, whereas FGF-2 mRNA transcription is known to decrease in adult testis. Interestingly, the FGF-2 IRES activation is triggered by testosterone and partially inhibited by siRNA directed against the androgen receptor. Two-dimensional analysis of proteins bound to the FGF-2 mRNA 5'UTR after UV cross-linking reveals that testosterone treatment correlates with the binding of several proteins. These data suggest a paracrine loop where IRES-dependent FGF-2 expression, stimulated by Sertoli cells in responseto testosterone produced by Leydig cells, would in turn activate Leydig function and testosterone production. In addition, nuclear FGF-2 isoforms could be involved in an intracrine function of FGF-2 in the start of spermatogenesis, mitosis or meiosis initiation. This report demonstrates that mRNA translation regulation by an IRES-dependent mechanism participates in a physiological process.
This thesis focus on Controlled Radical Polymerization (CRP) of vinyl esters and vinyl amides. One of the possibilities to achieve this control is a dynamic reversible trapping of the growing radical ...chains (P•) by a controlling agent (T) to form a dormant species (P─T’). The radical concentration in the medium can be dramatically reduced so that the unwanted terminations are disfavored and polymers with controlled molecular weights and low dispersity can be obtained. A way to achieve this control is the use of metallic complexes, which can oxidize and form a metal-carbon bond, as trapping agent in the so-called Organometallic Mediated Radical Polymerization (OMRP). So far, different transition metals have been used with gretaer or smaller success. In this study, the synthesis of copper(I) complexes and their investigation for the vinyl acetate and ethylene polymerization under OMRP conditions were performed. We also used computational chemistry as a tool to better understand why the cobalt(II) acetylacetonate (Co(acac)2) has, so far, given the best results for either vinyl acetate or vinyl amides polymerization. Thanks to Density Functional Theory (DFT), the crucial role of the monomer carbonyl group coordination to cobalt was pointed out.
Diversity in leaf shape is produced by alterations of the margin: for example, deep dissection leads to leaflet formation and less-pronounced incision results in serrations or lobes. By combining ...gene silencing and mutant analyses in four distantly related eudicot species, we show that reducing the function of NAM/CUC boundary genes (NO APICAL MERISTEM and CUP-SHAPED COTYLEDON) leads to a suppression of all marginal outgrowths and to fewer and fused leaflets. We propose that NAM/CUC genes promote formation of a boundary domain that delimits leaflets. This domain has a dual role promoting leaflet separation locally and leaflet formation at distance. In this manner, boundaries of compound leaves resemble boundaries functioning during animal development.
To characterize the cognitive abilities of patients with primary progressive multiple sclerosis (PPMS) and relapsing-remitting multiple sclerosis (RRMS) compared with healthy controls (HCs) matched ...for age, sex, and education level while considering the different characteristics of PPMS and RRMS and to compare the cognitive patterns of these types of multiple sclerosis.
Forty-one patients with PPMS, 60 patients with RRMS, and 415 HCs were recruited in a cross-sectional study. Controls were divided into 20 groups according to age, sex, and education level. Participants were assessed with a large battery of neuropsychological (NP) tests that included a modified version of the Brief Repeatable Battery, the Stroop test, computerized tests from the Test of Attentional Performance battery, the numerical span test, and the Rey Complex Figure.
Patients with PPMS performed worse than their matched HCs on nearly all NP tests. Patients with RRMS performed worse than matched HCs on a computerized digit-symbol substitution task and the alertness test, reaction time for visual scanning, and Paced-Auditory Serial Addition Test-3 seconds. Patients with PPMS had worse NP scores and were more impaired in cognitive domains than patients with RRMS. After controlling for Expanded Disability Status Scale score, the results remained unchanged.
The patients with PPMS presented with a wide range of cognitive deficits in information processing speed, attention, working memory, executive function, and verbal episodic memory, whereas the impairments in patients with RRMS were limited to information processing speed and working memory compared with their matched HCs. Cognitive deficits were more severe in patients with PPMS than in patients with RRMS.
In temperate ecosystems, acidic forest soils are among the most nutrient-poor terrestrial environments. In this context, the long-term differentiation of the forest soils into horizons may impact the ...assembly and the functions of the soil microbial communities. To gain a more comprehensive understanding of the ecology and functional potentials of these microbial communities, a suite of analyses including comparative metagenomics was applied on independent soil samples from a spruce plantation (Breuil-Chenue, France). The objectives were to assess whether the decreasing nutrient bioavailability and pH variations that naturally occurs between the organic and mineral horizons affects the soil microbial functional biodiversity. The 14 Gbp of pyrosequencing and Illumina sequences generated in this study revealed complex microbial communities dominated by bacteria. Detailed analyses showed that the organic soil horizon was significantly enriched in sequences related to Bacteria, Chordata, Arthropoda and Ascomycota. On the contrary the mineral horizon was significantly enriched in sequences related to Archaea. Our analyses also highlighted that the microbial communities inhabiting the two soil horizons differed significantly in their functional potentials according to functional assays and MG-RAST analyses, suggesting a functional specialisation of these microbial communities. Consistent with this specialisation, our shotgun metagenomic approach revealed a significant increase in the relative abundance of sequences related glycoside hydrolases in the organic horizon compared to the mineral horizon that was significantly enriched in glycoside transferases. This functional stratification according to the soil horizon was also confirmed by a significant correlation between the functional assays performed in this study and the functional metagenomic analyses. Together, our results suggest that the soil stratification and particularly the soil resource availability impact the functional diversity and to a lesser extent the taxonomic diversity of the bacterial communities.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Summary
The evolution of plant reproductive strategies has led to a remarkable diversity of structures, especially within the flower, a structure characteristic of the angiosperms. In flowering ...plants, sexual reproduction depends notably on the development of the gynoecium that produces and protects the ovules. In Arabidopsis thaliana, ovule initiation is promoted by the concerted action of auxin with CUC1 (CUP‐SHAPED COTYLEDON1) and CUC2, two genes that encode transcription factors of the NAC family (NAM/ATAF1,2/CUC). Here we highlight an additional role for CUC2 and CUC3 in Arabidopsis thaliana ovule separation. While CUC1 and CUC2 are broadly expressed in the medial tissue of the gynoecium, CUC2 and CUC3 are expressed in the placental tissue between developing ovules. Consistent with the partial overlap between CUC1, CUC2 and CUC3 expression patterns, we show that CUC proteins can physically interact, both in yeast cells and in planta. We found that the cuc2;cuc3 double mutant specifically harbours defects in ovule separation, producing fused seeds that share the seed coat, and suggesting that CUC2 and CUC3 promote ovule separation in a partially redundant manner. Functional analyses show that CUC transcription factors are also involved in ovule development in Cardamine hirsuta. Additionally we show a conserved expression pattern of CUC orthologues between ovule primordia in other phylogenetically distant species with different gynoecium architectures. Taken together these results suggest an ancient role for CUC transcription factors in ovule separation, and shed light on the conservation of mechanisms involved in the development of innovative structures.
Significance Statement
CUP‐SHAPED COTYLEDON transcription factors are key players in boundary definition, an important step in several developmental processes such as primordia initiation, axillary meristem formation, leaf dissection and ovule primordia outgrowth. We identify an additional role for CUC2 and CUC3 transcription factors in ovule separation in Arabidopsis, and provide data that suggests this role is conserved across different species, thus shedding light on the conservation of regulatory mechanisms in different developmental and evolutionary contexts.
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