Éditeur(s) : HAL CCSD BioMed Central
Résumé : International audience
Cell proliferation is a hallmark of cancer and depends on complex signaling networks that are chiefly supported by protein kinase activities. Therapeutic strategies have been used to target specific kinases but new methods are required to identify combined targets and improve treatment. Here, we propose a small interfering RNA genetic screen and an integrative approach to identify kinase networks involved in the proliferation of cancer cells. The functional siRNA screen of 714 kinases in HeLa cells identified 91 kinases implicated in the regulation of cell growth, most of them never being reported in previous whole-genome siRNA screens. Based on gene ontology annotations, we have further discriminated between two classes of kinases that, when suppressed, result in alterations of the mitotic index and provoke cell-cycle arrest. Extinguished kinases that lead to a low mitotic index mostly include kinases implicated in cytosolic signaling. In contrast, extinguished kinases that result in a high mitotic index mostly include kinases implicated in cell division. By mapping hit kinases in the PhosphPOINT phosphoprotein database, we generated scale-free networks consisting of 449 and 661 protein-protein interactions for kinases from low MI and high MI groups, respectively. Further analyses of the kinase interactomes revealed specific modules such as FER- and CRKL-containing modules that connect three members of the epidermal growth factor receptor (EGFR) family, suggesting a tight control of the mitogenic EGF-dependent pathway. Based on experimental studies, we confirm the involvement of these two kinases in the regulation of tumor cell growth. Based on a combined approach of large kinome-wide siRNA screens and ontology annotations, our study identifies for the first time two kinase groups differentially implicated in the control of cell proliferation. We further demonstrate that integrative analysis of the kinase interactome provides key information which can be used to facilitate or optimize target design for new therapeutic strategies. The complete list of protein-protein interactions from the two functional kinase groups will provide a useful database for future investigations.
ISSN: 1471-2164

hal-01118475
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01118475
DOI : 10.1186/1471-2164-15-1169
PUBMED : 25540073

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The emergent domain known as “Kasserine Island” in central Tunisia, to the West of the North–South Axis, was emerging during the Turonian. This area has undergone several changes during the Cretaceous–Eocene period. In the present study, the compilation of surface and sub-surface data provided new information about the boundaries variations of the emerged domain. The analysis of paleogeographic maps allowed the identification of three distinct stages of evolution. The first stage extents from the Middle Turonian to the Lower Maastrichtian where the emergent domain covers the area extending from Jebels Selloum-Sidi Aich in the West to Jebel Bouhedma in the East. The boundaries of this area coincide with the E–W Kasserine fault to the North, the N–S Lessouda-Boudinar fault in the East and the N 120 el Mech-Souinia flexure at the South. This emersion contemporaneous with a high eustatic level is most likely related to tectonic activity. The extensional tectonic regime that is characterized by a NE–SW minimal horizontal stress, has reactivated border faults with a normal component. The interference of the tilting of these border faults was at the origin of the emergence of this domain. The ascent of the Triassic salt may also have contributed in this uplift.In the second stage, the emerged domain has reached its maximum expansion to the North, the West and the South during the Middle Maastrichtian–Paleocene period. Its northern limit is irregular, while the southern limit coincides with the N120 Gafsa fault and the E–W fault of Jebels Orbata-Bouhedma. The N–S Lessouda-Boudinar fault forms the eastern limit. This expansion is mostly related to the global eustatic fall that is well characterized during this period, and partly to the compressive tectonic activity.The Lower Eocene is characterized by a marine transgression that has interested the northern edge of the Island, where the Ypresian deposits are discordant on older series. This edge was irregular and marked by the Gulf of Sbiba. The eastern, the southern, and the western boundaries kept the same shape as that of the previous stage. The compressive tectonic regime, characterized by a NW–SE maximum horizontal stress, is accentuated. This constraint state has generated NE–SW folds and NW–SE grabens. Some of these structures allowed the accumulation of a thick phosphate deposits at their edges, and continental deposits in the emerged area.During the Middle to Upper Eocene, the emergent area narrowed further at the North. The deposits are transgressive and discordant on older series. The Other limits always coincide with the Gafsa fault, the Jebels Orbata-Bouhedma and Jebels Lessouda-Boudinar faults. This period is characterized by the filling of the Gafsa basin by evaporate deposits before its emergence in the Oligocene. As a result, the southern-central Tunisia emerged as one area.
ISSN: 0899-5362

hal-01243490
https://hal.archives-ouvertes.fr/hal-01243490
DOI : 10.1016/j.jafrearsci.2015.07.027

Éditeur(s) : Elsevier
Résumé : A new method for the non-specific determination of iron-porphyrin-like complexes in natural waters has been developed. It is based on the chemiluminescent oxidation of the luminol in the presence of dioxygen (O-2) at pH 13. The method has been implemented in a FIA manifold that allowed the direct injection of seawater. The limit of detection is 0.11 nM of equivalent hemin (Fe-protoporphyrin IX). Fe2+, Fe3+, H2O2, siderophore (deferoxamin mesylate), humic acid and phytic acid did not interfere when the), were present at the concentrations expected in seawater. Metal free porphyrin and Mg, Cu, Co porphyrin complexes did not induce a significant chemiluminescent signal. Poisoned unfiltered samples could be stored for several weeks before analyses. The new method was successfully applied to the determination of the Fe-porphyrin complexes contained in cultured phytoplankton and in natural samples.
Analytica Chimica Acta (0003-2670) (Elsevier), 2007-04 , Vol. 588 , N. 2 , P. 237-244

Droits : 2007 Elsevier B.V. All rights reserved
http://archimer.ifremer.fr/doc/2007/publication-3298.pdf
DOI:10.1016/j.aca.2007.02.007
http://archimer.ifremer.fr/doc/00000/3298/

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Experimental studies have demonstrated that the antileukemic trivalent inorganic arsenic prevents the development of severe pro-inflammatory diseases mediated by excessive Th1 and Th17 cell responses. Differentiation of Th1 and Th17 subsets is mainly regulated by interleukins (ILs) secreted from dendritic cells (DCs) and the ability of inorganic arsenic to impair interferon-γ and IL-17 secretion by interfering with the physiology of DCs is unknown. In the present study, we demonstrate that high concentrations of sodium arsenite (As(III), 1-2 μM) clinically achievable in plasma of arsenic-treated patients, block differentiation of human peripheral blood monocytes into immature DCs (iDCs) by inducing their necrosis. Differentiation of monocytes in the presence of non-cytotoxic concentrations of As(III) (0.1 to 0.5 μM) only slightly impacts endocytotic activity of iDCs or expression of co-stimulatory molecules in cells activated with lipopolysaccharide. However, this differentiation in the presence of As(III) strongly represses secretion of IL-12p70 and IL-23, two major regulators of Th1 and Th17 activities, from iDCs stimulated with different toll-like receptor (TLR) agonists in metalloid-free medium. Such As(III)-exposed DCs also exhibit reduced mRNA levels of IL12A and/or IL12B genes when activated with TLR agonists. Finally, differentiation of monocytes with non-cytotoxic concentrations of As(III) subsequently reduces the ability of activated DCs to stimulate the release of interferon-γ and IL-17 from Th cells. In conclusion, our results demonstrate that clinically relevant concentrations of inorganic arsenic markedly impair in vitro differentiation and functions of DCs, which may contribute to the putative beneficial effects of the metalloid towards inflammatory autoimmune diseases.
ISSN: 0041-008X

inserm-00813758
http://www.hal.inserm.fr/inserm-00813758
DOI : 10.1016/j.taap.2012.11.008
PUBMED : 23164666

Éditeur(s) : HAL CCSD
Résumé : Hepatitis C virus (HCV) is one of the leading causes of hepatocellular carcinoma. Therapeutic treatment against the virus has been recently improved by a tritherapy including pegylated interferon, ribavirin and antiviral protease. Nevertheless, the importance of side effects and the emergence of resistant mutants require the development of new antivirals. In this context, our team has recently discovered that Type III phosphatidylinositol 4-kinases (PI4KIIIα and PI4KIIIβ) are essential for the propagation of the virus in a human hepatic cell line at the entry and replication steps. To further characterize these potential therapeutic targets, we investigate the implication of these kinases during the HCV entry, using primary human hepatocytes, a model closer to the in vivo conditions. Two lines of research were developed: Verification of the importance of the kinase activity of PI4KIIIs during HCV entry in primary human hepatocytes, through a chemical approach; Validation of the involvement of these kinases and their enzymatic activity during viral entry through a genetic approach based on RNA interference and phenotype rescue. In parallel, we studied the expression of PI4KIIIα in liver diseases. Our results suggest the involvement of PI4KIIIα in HCV entry; the involvement of PI4KIIIIβ needs to be confirmed. The analysis of PI4KIIIα expression in hepatocellular carcinoma led us to propose this kinase as a new molecular marker, which could improve the already established prognosis models and could lead to the development of new therapeutic approaches.
Le virus de l’hépatite C (VHC) est l’un des principaux facteurs étiologiques du carcinome hépatocellulaire. Le traitement des hépatites virales C a été récemment amélioré grâce à une trithérapie (interféron, ribavirine et anti-protéase virale). Néanmoins l’importance des effets secondaires et l’émergence de mutants résistants nécessitent de découvrir de nouveaux antiviraux. Dans ce contexte, notre équipe a récemment découvert que les phosphatidylinositol 4-kinases de type III (PI4KIIIα et PI4KIIIβ) étaient indispensables à la propagation du virus dans une lignée hépatique humaine, et ce, à 2 étapes de son cycle biologique : l’entrée et la réplication. L’objectif du présent travail était de poursuivre la validation de ces nouvelles cibles thérapeutiques potentielles, en approfondissant nos connaissances sur la dépendance du virus à l’égard de ces kinases au cours de son entrée. Pour cela, nous avons utilisé le modèle des hépatocytes humains primaires, système in vitro plus proche du contexte physiologique que les modèles utilisés jusqu’à présent et qui étaient basés sur l’exploitation de lignées. Deux axes ont été développés : Vérification de l’importance de l’activité kinase des PI4KIIIs au cours de l’entrée du VHC dans les hépatocytes humains primaires, à travers une approche chimique ; Validation de l’implication de ces kinases et de leur activité enzymatique au cours de l’entrée virale grâce à une approche génétique basée sur l’ARN interférence et la restauration de phénotype. En parallèle, nous avons étudié l’expression de PI4KIIIα au cours de pathologies hépatiques. Nos résultats suggèrent une implication de PI4KIIIα au cours de l’entrée du VHC dans les hépatocytes humains primaires, mais restent à confirmer quant à l’implication de PI4KIIIβ. Par ailleurs, l’analyse de l’expression de PI4KIIIα dans le carcinome hépatocellulaire (CHC) conduit à proposer cette kinase comme un nouveau marqueur moléculaire, qui pourrait améliorer les modèles de pronostic déjà établis et pourrait conduire au développement de nouvelles approches thérapeutiques pour les patients atteints d’un CHC, quelque soit l’étiologie.
https://tel.archives-ouvertes.fr/tel-00950335

Droits : info:eu-repo/semantics/OpenAccess
NNT : 2013REN1B006
tel-00950335
https://tel.archives-ouvertes.fr/tel-00950335
https://tel.archives-ouvertes.fr/tel-00950335/document
https://tel.archives-ouvertes.fr/tel-00950335/file/ILBOUDOAdeodat.pdf

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
A thorough phytochemical study of Stereocaulon evolutum was conducted, for the isolation of structurally related atranorin derivatives. Indeed, pilot experiments suggested that atra-norin (1), the main metabolite of this lichen, would interfere with the lifecycle of hepatitis C virus (HCV). Eight compounds, including one reported for the first time (2), were isolated and characterized. Two analogs (5, 6) were also synthesized, to enlarge the panel of atra-norin-related structures. Most of these compounds were active against HCV, with a half-maximal inhibitory concentration of about 10 to 70 µM, with depsides more potent than monoaromatic phenols. The most effective inhibitors (1, 5 and 6) were then added at different steps of the HCV lifecycle. Interestingly, atranorin (1), bearing an aldehyde function at C-3, inhibited only viral entry, whereas the synthetic compounds 5 and 6, bearing a hydroxy-methyl and a methyl function, respectively, at C-3 interfered with viral replication.
ISSN: 1932-6203

hal-01134343
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01134343
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01134343/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01134343/file/Depsides-PloS.pdf
DOI : 10.1371/journal.pone.0120405

Éditeur(s) : HAL CCSD Frontiers Media
Résumé : International audience
The Anopheles midgut hosts diverse bacterial communities and represents a complex ecosystem. Several evidences indicate that mosquito midgut microbiota interferes with malaria parasite transmission. However, the bacterial composition of salivary glands and ovaries, two other biologically important tissues, has not been described so far. In this study, we investigated the dynamics of the bacterial communities in the mosquito tissues from emerging mosquitoes until 8 days after a blood meal containing Plasmodium falciparum gametocytes and described the temporal colonization of the mosquito epithelia. Bacterial communities were identified in the midgut, ovaries, and salivary glands of individual mosquitoes using pyrosequencing of the 16S rRNA gene. We found that the mosquito epithelia share a core microbiota, but some bacteria taxa were more associated with one or another tissue at a particular time point. The bacterial composition in the tissues of emerging mosquitoes varied according to the breeding site, indicating that some bacteria are acquired from the environment. Our results revealed temporal variations in the bacterial community structure, possibly as a result of the mosquito physiological changes. The abundance of Serratia significantly correlated with P. falciparum infection both in the midgut and salivary glands of malaria challenged mosquitoes, which suggests that interactions occur between microbes and parasites. These bacteria may represent promising targets for vector control strategies. Overall, this study points out the importance of characterizing bacterial communities in malaria mosquito vectors.
ISSN: 1664-302X

hal-01546162
https://hal.archives-ouvertes.fr/hal-01546162
DOI : 10.3389/fmicb.2015.01500

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The volume comprises some of the contributions presented during the 10th edition of the Alpine Meeting "CorseAlp 2011". It has been held in Saint Florent (Corsica) between 10th and 16th of April 2011 under the auspices of Societé Geologique de France, Società Geologica Italiana and the INGV (Istituto Nazionale di Geofisica e Vulcanologia) and with the collaboration of colleagues of Université de Corse (M.-M. Spella, M. and J. Ferrandini and L. Ciancaleoni) and the support of the city council of S. Florent. The meeting was framed in the series of "Alpine Workshops" e.g., Siegesmund et al. (2008), Handy and Rosenberg (2011), which are held every two years to develop interdisciplinary research on Alpine-type orogens. It hosted a variety of topical sessions from regional geology to process-oriented field and laboratory studies and gave the opportunity to collect multidisciplinary and multiscale approaches to geodynamic studies including continental rifting and ocean opening, oceanic and continental subduction, late- to post orogenic extension, exhumation of deep seated rocks, back-arc opening and microcontinent rotation, interfering orogenic-scale tectonics and surface processes, tectonics and seismic hazard within the Alpine chain and Mediterranean realms.
ISSN: 0040-1951

hal-00795580
https://hal.archives-ouvertes.fr/hal-00795580

Éditeur(s) : HAL CCSD American Chemical Society
Résumé : International audience
The 90-kDa heat shock protein (Hsp90) is a highly flexible dimer able to self-associate in the presence of divalent cations or under heat shock. This study investigated the relationship between Hsp90 oligomers and the Hsp90 cochaperone Aha1 (activator of Hsp90 ATPase). The interactions of Aha1 with Hsp90 dimers and oligomers were evaluated by ultracentrifugation, size-exclusion chromatography coupled to multiangle laser light scattering and high-mass matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Hsp90 dimer was able to bind up to four Aha1 molecules, and Hsp90 oligomers are also able to interact with Aha1. The binding of Aha1 did not interfere with the Hsp90 oligomerization process. Except for Hsp90 dimer, the stoichiometry of the interaction remained constant, at 2 Aha1 molecules per Hsp90 dimer, regardless of the degree of Hsp90 oligomerization. Moreover, Aha1 predominantly bound to Hsp90 oligomers. Thus, the ability of Hsp90 oligomers to bind the Aha1 ATPase activator reinforces their role within the Hsp90 chaperone machineries
ISSN: 0003-2700

hal-01175535
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01175535
DOI : 10.1021/acs.analchem.5b00051
PUBMED : 26076190

Éditeur(s) : HAL CCSD
Résumé :  
Afin de comprendre l'organisation des communautés de chauves-souris ainsi que la coexistence de nombreuses espèces sympatriques, il est essentiel de déterminer comment les espèces utilisent et se partagent les ressources. Dans un premier temps, nous décrivons un peuplement de chauves-souris en forêt primaire de Guyane Française. Les facteurs locaux tels que la présence de gîtes particuliers comme les grottes, ou l'absence de perturbation anthropique ont une influence sur la structure et la composition des communautés. Au cours de cette étude, nous nous sommes concentrés sur les trois espèces les plus communes de chaque guilde végétarienne (frugivores de sous-bois, frugivores de canopée et nectarivores). Leur coexistence est possible grâce au partage des ressources alimentaires, de l'espace et/ou du temps. Au sein d'une même guilde, les plus petites espèces ont une bonne manoeuvrabilité et semblent occuper davantage les espaces fermés, moins attractifs pour leurs compétiteurs. Elles ont aussi un domaine vital plus petit que les grandes espèces. De même, le décalage des rythmes d'activités que nous avons observé, peut réduire la compétition entre les chauves-souris frugivores en diminuant les interférences directes lors de l'alimentation. En plus d'un intérêt pour l'écologie des communautés, cette étude décrivant des peuplements de chiroptères dans une forêt primaire intacte, peut servir de référence en biologie de conservation.
Revue d'écologie

hal-01032160
https://hal.archives-ouvertes.fr/hal-01032160

Éditeur(s) : HAL CCSD BioMed Central
Résumé : International audience
BACKGROUND: Environmental factors such as pesticides can cause phenotypic changes in various organisms, including mammals. We studied the effects of the widely used herbicide atrazine (ATZ) on meiosis, a key step of gametogenesis, in male mice. METHODS: Gene expression pattern was analysed by Gene-Chip array. Genome-wide mapping of H3K4me3 marks distribution was done by ChIP-sequencing of testis tissue using Illumina technologies. RT-qPCR was used to validate differentially expressed genes or differential peaks. RESULTS: We demonstrate that exposure to ATZ reduces testosterone levels and the number of spermatozoa in the epididymis and delays meiosis. Using Gene-Chip and ChIP-Seq analysis of H3K4me3 marks, we found that a broad range of cellular functions, including GTPase activity, mitochondrial function and steroid-hormone metabolism, are affected by ATZ. Furthermore, treated mice display enriched histone H3K4me3 marks in regions of strong recombination (double-strand break sites), within very large genes and reduced marks in the pseudoautosomal region of X chromosome. CONCLUSIONS: Our data demonstrate that atrazine exposure interferes with normal meiosis, which affects spermatozoa production
ISSN: 1471-2164

hal-01225493
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01225493
DOI : 10.1186/s12864-015-2095-y
PUBMED : 26518232

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
In this work, we have studied quenching of the fluorescence of two well-known oxygen probes, 1-pyrene butyric acid (PBA) and tris(2,2'-bipyridine)ruthenium ([Ru(bpy)(3)](2+)) by reactive oxygen species (superoxide anion, nitric oxide derivative, hydrogen peroxide) and by the O(2) molecule. Both, time-resolved and steady state fluorescence measurements were performed in solution (ethanol, dimethyl sufoxide, water) and in micelles of Sodium Dodecyl Sulfate that serve as a model for membrane-containing biological structures. We have found that only the free radicals and O(2) can actively quench for the two probes, but not the diamagnetic H(2)O(2). Our data correspond to the classical Stern-Volmer equation. H(2)O(2) has an effect only at high molar concentrations (>0.1 M). In contrast, effective concentrations of free radicals and O(2) that lead to quenching are in millimolar range. In conclusion, our methods allows for detecting global ROS that are small free radicals without interference from the reactive hydroxyl radical. Our data suggest that the method can be used for the quantification of ROS in individual living cells based on the measurement of fluorescence lifetime of those probes
ISSN: 1053-0509

hal-01326234
https://hal.archives-ouvertes.fr/hal-01326234
DOI : 10.1007/s10895-008-0425-z

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
Meconium is the earliest stool of newborns, and is a complex matrix that reflects the degree of exposure of the fetus to xenobiotics. To investigate fetal exposure to volatile organic compounds, an analytical method was developed to identify and quantify BTEX (benzene, toluene, ethylbenzene, and o,m,p-xylene) and two chlorinated solvents (trichloroethylene and tetrachloroethylene) in meconium. Headspace-solid-phase microextraction coupled with gas chromatography-mass spectrometry was selected because it is simple, sensitive, can be automated, and requires no extensive sample preparation. Several extraction variables were optimized (fiber type, incubation time, temperature of fiber, and use of salt). Because meconium is a complex matrix, quantification by SPME was considered carefully because of potential interference, for example competitive adsorption. Calibration in water was compared with calibration in meconium using external and internal methods (with isotope-labeled compounds). In meconium, limits of quantification were determined to be in the range 0.064-0.096 ng g(-1) for the investigated compounds. All target compounds were determined in "real-case" meconium samples.
ISSN: 1618-2642

hal-01064967
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01064967
DOI : 10.1007/s00216-014-7836-2
PUBMED : 24838489

Éditeur(s) : HAL CCSD PubMed
Résumé : International audience
To investigate thermal response, hydration behaviour and performance over flatwater kayaking races in tropical conditions (36.8°C and 68 % rh). Five internationally-ranked subjects participated in the 2012 Surfski Ocean Racing World Cup in Guadeloupe to the “Ze Caribbean Race 2012” [i.e., a 35-km downwind race]. Core temperature (T°C) and heart rate (HR) were measured using portable telemetry units whereas water intake was deduced from backpacks absorption. The kayakers were asked to rate both their comfort sensation and thermal sensation on a scale before and after the race. The performance was related to an increase in T°C, high HR and low water intake (WI); and (2) high values of final T°C were related to high pre T°C and greater increases in T°C being obtained with low pre T°C and (3) WI being related to high pre T°C. The present study demonstrated that the fastest kayakers were those able to paddle at the highest intensities, increasing their T°C and drinking little water without any interference from thermal sensations. Water intake was positively related to pre-race T°C, which reinforces the importance of beginning surfski races with a low T°C. This study demonstrated that well-trained kayakers drinking ad libitum were able to anticipate their intensity/heat storage ratio to prevent heat illness and severe dehydration and maintain high performance.
ISSN: 0860-021X

hal-01137286
https://hal.univ-antilles.fr/hal-01137286

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Structural controls are critical during magmatic-to-hydrothermal transition in the formation of intrusion-related gold deposits. They may explain why only some parts of intrusions are mineralized and why only very few intrusions host large deposits. Moreover, most of these gold deposits postdate peak regional metamorphism and were formed in zones of relatively low strain. Indeed, the efficiency of structural gold traps is highest along favourably oriented intrusion/host-rock contacts where mechanical instability maintains high permeability in the cracked thermal aureole. This may be reinforced by melt injections from an underlying root zone. We present a structural analysis of the deformation features of a granite-pluton roof; large-scale dykes and a network of gold veins are intensively developed in this roof, recording a succession of mechanical instabilities. Our gravity survey underlines the presence of a pluton feeder zone located just beneath the mineralized network. It is argued that interferences between regional stress and melt injection in the feeder zone favoured the development of the network by strain located close to the granite roof. This stresses the role of mechanical instabilities triggered by the combined effects of regional stress and melt dynamics in determining the location and size of this type of gold deposit.
ISSN: 0191-8141

insu-00914780
https://hal-insu.archives-ouvertes.fr/insu-00914780
https://hal-insu.archives-ouvertes.fr/insu-00914780/document
https://hal-insu.archives-ouvertes.fr/insu-00914780/file/manuscript.pdf
DOI : 10.1016/j.jsg.2013.11.006

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
During the treatment process of drinking water, disinfectants (chlorine, ozone, chlorine dioxide) react on water containing organic matter and bromide to produce disinfection by-products at trace levels. Among them, five of the nine existing halo-acetic acids (HAAs) are commonly found in drinking water (monochloroacetic acid (MCAA), dichloroacetic acid (DCAA), monobromoacetic acid (MBAA), dibromoacetic acid (DBAA), and Trichloroacetic acid (TCAA)), including four classified in the 2B IARC group of potential carcinogens (BCAA, DBAA, DCAA, TCAA). With respect to drinking water quality, guidelines are proposed by WHO (2006) and water quality standards are imposed in many countries such as less than 100 μg/L for the sum of the five HAAs by US EPA (1998) and Canadian Health Department (2008). For this purpose, two analytical methods are commonly used, GC/MS with derivatization and LC/MS, UV or conductivity. A new method, based on two-dimensional ion chromatography (IC 2D) with suppressed conductivity is proposed. This method presents the main advantage of offering a quick implementation compared to GC or LC methods: direct injection, slight maintenance, lower cost of investment, by leading to good performances (specificity and sensitivity). The use of two different selectivity columns, and the fractionation on the first dimension canceling interferences, improves the specificity. The sensitivity is enabled by interfacing a preconcentration column between the two different internal diameter columns. The analytical conditions are optimized for the analysis of nine HAAs. The performances of the method are evaluated. The optimized method applied to natural water samples demonstrates its ability to quantify HAAs at trace levels in drinking water.
Microchemical Journal

hal-00877151
https://hal-univ-rennes1.archives-ouvertes.fr/hal-00877151
https://hal-univ-rennes1.archives-ouvertes.fr/hal-00877151/document
DOI : 10.1016/j.microc.2013.07.012

Éditeur(s) : HAL CCSD
Résumé : Monitoring crustal deformation during the interseismic phase when searching for earth transients requires precise instruments able to operate for very long periods. The ANR-LINES project aimed to develop three new instruments: a single-axis seismometer, a hydrostatic long base tiltmeter and a borehole pendulum tiltmeter. These three instruments benefit of an extrinsic Fabry-Pérot interferometer (EFFPI) with long optic fibers for displacement detections. Their mechanical architectures and their disposal of long fibers help these newly manufactured geophysical instruments complete their goals. The first objective of this study is to propose appropriate methods for estimating the phase of the optical path in the Fabry-Pérot cavities. A modulation of the laser diode current, followed by a homodyne demodulation of the interference signal and a Kalman filter, allow determining the phase in real time. The results are convincingwhile taking short periods measurements but require additional solutions for protection against environmental phenomena variations. The EFFPI sensor integrated in the LINES borehole tiltmeter gives it the opportunity to establish a differential measurement of the bob's oscillation thanks to three Fabry-Perot cavities. The LINES seismometer also uses the EFFPI displacement sensor to measure its coil's displacement. A description of the two instruments' mechanical structures and an analysis of the detected phenomena (slow movements, tides, earthquakes, microseisms . . . ) are part of this thesis.
Le suivi de la déformation de la croûte terrestre durant la phase intersismique pour la recherche des transitoires nécessite des instruments précis capables d'opérer pour de très longues durées. Le projet ANR-LINES a visé le développement de trois nouveaux instruments : un sismomètre mono-axial, un inclinomètre hydrostatique à longue base et un inclinomètre de forage pendulaire. Ces trois instruments profitent d'un capteur interférométrique de déplacement à longues fibres optiques du type Fabry-Pérot Extrinsèque (EFFPI). Leurs architectures mécaniques et l'utilisation de longues fibres permettent à ces instruments géophysiques nouvellement fabriqués d'atteindre les objectifs fixés. Le premier objectif de cette étude est de proposer des méthodes adaptées à l'estimation de la phase du chemin optique dans les cavités Fabry-Pérot. Une modulation du courant de la diode laser, suivie par une démodulation homodyne du signal d'interférence et un filtre de Kalman permettent de déterminer la phase en temps réel. Les résultats sont convaincants pour des mesures de courtes durées mais exigent des solutions complémentaires pour se prémunir des effets de la variation des phénomènes environnementaux. Le capteur EFFPI intégré dans l'inclinomètre de forage LINES lui offre l'opportunité d'établir une mesure différentielle de l'oscillation de la masselotte pendulée grâce à trois cavités Fabry-Pérot. Le sismomètre LINES utilise lui aussi le capteur de déplacement EFFPI pour la mesure du déplacement de sa bobine. Une description de l'architecture mécanique de ces instruments et une analyse des phénomènes détectés (mouvements lents, marées, séismes, microséismes . . . ) font partie de cette thèse.
https://tel.archives-ouvertes.fr/tel-00779335

tel-00779335
https://tel.archives-ouvertes.fr/tel-00779335
https://tel.archives-ouvertes.fr/tel-00779335/document
https://tel.archives-ouvertes.fr/tel-00779335/file/Manuscript_Chawah.pdf

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
BACKGROUND: Studies relating long-term exposure to persistent organochlorine pollutants (POPs) with endocrine activities (endocrine disrupting chemicals) on circulating levels of steroid hormones have been limited to a small number of hormones and reported conflicting results. OBJECTIVE: We examined the relationship between serum concentrations of dehydroepiandrosterone, dehydroepiandrosterone sulphate, androstenedione, androstenediol, testosterone, free and bioavailable testosterone, dihydrotestosterone, estrone, estrone sulphate, estradiol, sex-hormone binding globulin, follicle-stimulating hormone, and luteinizing hormone as a function of level of exposure to three POPs known to interfere with hormone-regulated processes in different way: dichlorodiphenyl dichloroethene (DDE), polychlorinated biphenyl (PCB) congener 153, and chlordecone. METHODS: We collected fasting, morning serum samples from 277 healthy, non obese, middle-aged men from the French West Indies. Steroid hormones were determined by gas chromatography-mass spectrometry, except for dehydroepiandrosterone sulphate, which was determined by immunological assay, as were the concentrations of sex-hormone binding globulin, follicle-stimulating hormone and luteinizing hormone. Associations were assessed by multiple linear regression analysis, controlling for confounding factors, in a backward elimination procedure, in multiple bootstrap samples. RESULTS: DDE exposure was negatively associated to dihydrotestosterone level and positively associated to luteinizing hormone level. PCB 153 was positively associated to androstenedione and estrone levels. No association was found for chlordecone. CONCLUSIONS: These results suggested that the endocrine response pattern, estimated by determining blood levels of steroid hormones, varies depending on the POPs studied, possibly reflecting differences in the modes of action generally attributed to these compounds. It remains to be investigated whether this response pattern is predictive of the subsequent occurrence of disease.
ISSN: 1932-6203

hal-00876025
https://hal.archives-ouvertes.fr/hal-00876025
https://hal.archives-ouvertes.fr/hal-00876025/document
https://hal.archives-ouvertes.fr/hal-00876025/file/Persistent_Organochlorine-accepted.pdf
DOI : 10.1371/journal.pone.0066460

Éditeur(s) : HAL CCSD American Geophysical Union
Résumé : International audience
The anisotropic single crystal seismic properties are reviewed in the light of recent experimental and theoretical determinations. Although considerable progress has been made on the determination of single crystal properties, data are still lacking, particularly for the temperature derivatives of transition zone and lower mantle phases. The common types of LPO of olivine, opx and cpx are presented together with their associated seismic properties. It is emphasized that simple seismic symmetry pattern of upper mantle rocks are a direct result of the interaction of olivine, opx and cpx. Using the standard structural frame (X lineation, Z pole to foliation) for typical LPOs of olivine, opx and cpx have the maximum Vp parallel to X, in the XZ plane and parallel to Y respectively. Destructive interference occurs between these minerals and hence P-wave anisotropy should be sensitive to the aggregate composition. For shear wave splitting (dVs) typical olivine and opx LPOs result in similar patterns with the maximum dVs in the YZ plane and the fast split shear wave (Vs1) polarized parallel to the foliation. A typical cpx LPO on the other hand produces destructive interference as the max dVs is close to X. By comparison with experiments and numerical simulations, it is estimated that upper mantle samples have an olivine LPO strength which recorded shear strain gamma of between 0.25 and 2.0. Pyrolite and piclogite models are compared with global transverse isotropic models. The slowly reducing P-wave anisotropy in the first 200 km can be explained by a model with constant composition and LPO strength. The sharp decrease in the observed anisotropy in the global models cannot be explained by the transformation of opx to cpx at 300 km, it is proposed that this decrease is due to a reduction in LPO strength from 200 to 350 km at the base of the lithosphere.
Earth's Deep Interior: Mineral Physics and Tomography From the Atomic Scale to the Global Scale

ISBN : 9780875909752
hal-01391524
http://hal.univ-reunion.fr/hal-01391524
http://hal.univ-reunion.fr/hal-01391524/document
http://hal.univ-reunion.fr/hal-01391524/file/Mainprice_AGUmonog_DM_GB_WBI_2000.pdf

Éditeur(s) : HAL CCSD Wiley-Blackwell
Résumé : International audience
We show that MLCK (myosin light chain kinase) plays a key role in cell cycle progression of hepatocytes: either chemical inhibitor ML7 or RNA interference led to blockade of cyclin D1 expression and DNA replication, providing evidence that MLCK regulated S phase entry. Conversely, inhibition of RhoK by specific inhibitor Y27632 or RhoK dominant-negative vector did not influence progression in late G1 and S phase entry. Inhibition of either MLCK or RhoK did not block ERK1/2 phosphorylation, whereas MLCK regulated ERK2-dependent p70S6K activation. In addition, DNA synthesis was reduced in hepatocytes treated with p70S6K siRNA, demonstrating the key role played by the kinase in S phase entry. Interestingly, after the G1/S transition, DNA replication in S phase was no longer dependent on MLCK activity. We strengthened this result by ex vivo experiments and evidenced an MLCK-dependent window in late G1 phase of regenerating liver after two-thirds partial hepatectomy. In conclusion, our results underline an MLCK-dependent restriction point in G1/S transition, occurring downstream of ERK2 through the regulation of p70S6K activation, and highlighting a new signaling pathway critical for hepatocyte proliferation.
ISSN: 0270-9139

hal-00702089
https://hal.archives-ouvertes.fr/hal-00702089
DOI : 10.1002/hep.21222
PUBMED : 16799973