Éditeur(s) : HAL CCSD L'Harmattan
Résumé : National audience
Les Victoriens, que l'on se représente généralement comme des gens à la morale stricte et à l'imaginaire entravé par un matérialisme triomphant, étaient en même temps des rêveurs utilisant volontiers la fantaisie utopique et les contes de fées comme medium privilégié pour échapper par l'imagination à un réel perçu comme absurde ou cruel. Ainsi, le monde virtuel qu'ils inventèrent, ou-topos ou eu-topos, littéralement lieu de nulle part ou pays des merveilles ne peut-il exister que comme double inversé de leur univers quotidien. Leurs ailleurs se présentent donc comme l'envers de l'endroit (point de référence du narrateur). Envers et revers : selon une polarisation dialectique, l'ici et l'ailleurs se renvoient l'un à l'autre et n'existent que dans leur opposition.
Visions de l'Ailleurs

hal-00967465
https://hal.univ-antilles.fr/hal-00967465
https://hal.univ-antilles.fr/hal-00967465/document
https://hal.univ-antilles.fr/hal-00967465/file/AilleursVictoriens.pdf

Éditeur(s) : HAL CCSD Wiley Open Access
Résumé : International audience
Assessing population connectivity is necessary to construct effective marine protected areas. This connectivity depends, among other parameters, inherently on species dispersal capacities. Isolation by distance (IBD) is one of the main modes of differentiation in marine species, above all in species presenting low dispersal abilities. This study reports the genetic structuring in the tropical hydrozoan Macrorhynchia phoenicea (sensu Postaire et al., 2016a), a brooding species, from 30 sampling sites in the Western Indian Ocean and the Tropical Southwestern Pacific, using 15 microsatellite loci. At the local scale, genet dispersal relied on asexual propagation at short distance, which was not found at larger scales. Considering one representative per clone, significant positive F-IS values (from -0.327*** to 0.411***) were found within almost all sites. Gene flow was extremely low at all spatial scales, among sites within islands (<10km distance) and among islands (100 to >11,000km distance), with significant pairwise F-ST values (from 0.035*** to 0.645***). A general pattern of IBD was found at the Indo-Pacific scale, but also within ecoregions in the Western Indian Ocean province. Clustering and network analyses identified each island as a potential independent population, while analysis of molecular variance indicated that population genetic differentiation was significant at small (within island) and intermediate (among islands within province) spatial scales. As shown by this species, a brooding life cycle might be corollary of the high population differentiation found in some coastal marine species, thwarting regular dispersal at distances more than a few kilometers and probably leading to high cryptic diversity, each island housing independent evolutionary lineages.
ISSN: 2045-7758

hal-01681593
https://hal.archives-ouvertes.fr/hal-01681593
DOI : 10.1002/ece3.3236

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The effects of some progestins on fish reproduction have been recently reported revealing the hazard of this class of steroidal pharmaceuticals. However, their effects at the central nervous system level have been poorly studied until now. Notwithstanding, progesterone, although still widely considered primarily a sex hormone, is an important agent affecting many central nervous system functions. Herein, we investigated the effects of a large set of synthetic ligands of the nuclear progesterone receptor on the glial-specific expression of the zebrafish brain aromatase (cyp19a1b) using zebrafish mechanism-based assays. Progesterone and 24 progestins were first screened on transgenic cyp19a1b-GFP zebrafish embryos. We showed that progesterone, dydrogesterone, drospirenone and all the progesterone-derived progestins had no effect on GFP expression. Conversely, all progestins derived from 19-nortesterone induced GFP in a concentration-dependent manner with EC50 ranging from the low nM range to hundreds nM. The 19-nortestosterone derived progestins levonorgestrel (LNG) and norethindrone (NET) were further tested in a radial glial cell context using U251-MG cells co-transfected with zebrafish ER subtypes (zfER alpha, zfER beta 1 or zfER beta 2) and cyp19a1b promoter linked to luciferase. Progesterone had no effect on luciferase activity while NET and LNG induced luciferase activity that was blocked by ICI 182,780. Zebrafish-ERs competition assays showed that NET and LNG were unable to bind to ERs, suggesting that the effects of these compounds on cyp19a1b require metabolic activation prior to elicit estrogenic activity. Overall, we demonstrate that 19-nortestosterone derived progestins elicit estrogenic activity by inducing cyp19a1b expression in radial glial cells. Given the crucial role of radial glial cells and neuro-estrogens in early development of brain, the consequences of exposure of fish to these compounds require further investigation.
ISSN: 0041-008X

hal-01366373
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01366373
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01366373/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01366373/file/Several%20synthetic%20progestins%20disrupt%20the%20glial%20cell.pdf
DOI : 10.1016/j.taap.2016.05.019

Éditeur(s) : HAL CCSD
Résumé : Food-grade dairy propionibacteria are nutraceutical producers. They release short chain fatty acids (SCFAs), folic acid and cobalamin, which play a role in intestinal physiology. SCFAs induce apoptosis via the mitochondrial death pathway. We investigated the potential of dairy propionibacteria-fermented products to synergize with drugs used in gastric and colorectal cancer.Fermented milk contained high and viable populations of propionibacteria. This product, as well as its cell-free supernatant, were tested in vitro on gastric HGT-1 and colic HT-29 cells with respect to apoptosis and synergy with known anti-cancer molecules, camptothecin and the human cytokine TRAIL (TNF Related Apoptosis Inducing Ligand). Viability was monitored and apoptosis quantified by Hoescht staining, ROS production, mitochondrial membrane potential perturbation and caspases activity assay. A transcriptomic study on genome-wide microarray was performed in collaboration with the company Miltenyi.Fermented milk induced cell death in both gastric and colon cancer cells. Characterization of cells revealed cell cycle arrest, drop in intracellular ATP, depolarization of mitochondria, translocation of key apoptosis proteins, processing of caspases and fragmentation of the nucleus. Interestingly, the fermented milk was shown to potentiate the cytotoxic effect of molecules used in cancer chemotherapy, camptothecin and TRAIL. The observed synergistic pro-apoptotic effect between TRAIL and propionibacterial SCFAs depended on death receptors and on caspases, was more lethal on cancer cells than on normal human intestinal epithelial cells (HIEC), and was inhibited by Bcl-2 expression. Transcriptomics revealed that propionibacterial metabolites boosted TRAIL-induced modulation of gene expression in human colon cancer cells.These results open new perspectives in the field of colon cancer cells prevention and/or treatment. The synergy with pro-apoptotic chemotherapy molecules suggests that such a fermented product, or the propionibacterium alone, may be proposed as a food supplement to enhance the effects of anticancer treatments.
The 2nd International conference on Cell Death In Cancer (CDIC)
La Baule, France

hal-01209622
https://hal.archives-ouvertes.fr/hal-01209622
PRODINRA : 261291

Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
Hydroxycarbamide (HC) treatment has been shown to improve the clinical course of patients with sickle cell anaemia (SCA), a haemoglobinopathy resulting from a single base substitution in the bêta-globin gene (HBB). SCA is characterized by chronic haemolytic anaemia and recurrent vascular occlusions leading to multisystemic complications. Several beneficial biological effects of HC have been documented (Halsey et al, 2003) but its impact on the concentration of circulating microparticles (MPs), a subtype of extracellular vesicles released from cytoplasmic membrane of activated or apoptotic cells and detected at high levels in sickle plasma, remains controversial (Hebbel et al, 2016). The aim of the present study was to compare the MP pattern in a group of SCA patients treated by HC and followed for 2 years.
ISSN: 0007-1048

hal-01668320
https://hal.univ-antilles.fr/hal-01668320
https://hal.univ-antilles.fr/hal-01668320/document
https://hal.univ-antilles.fr/hal-01668320/file/Garnier%20et%20al%20BJH-2017-00655.pdf
DOI : 10.1111/bjh.14810

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
We explore the relationships within Serraniformes (Li et al., 2009) using a dense taxon sampling and seven nuclear markers. Six had already used been for teleost phylogeny (IRBP, MC1R, MLL4, Pkd1, Rhodopsin, and RNF213) at other scales, and one (MLL2) is new. The results corroborate the composition of Serraniformes described in previous publications (some Gasterosteiformes, Perciformes and Scorpaeniformes). Within the clade, Notothenioidei and Zoarcoidei are each monophyletic. Cottoidei was not monophyletic due to placement of the genus Ebinania (Psychrolutidae). Our independent data confirm the sister-group relationship of Percophidae and Notothenioidei as well as the division of Platycephaloidei in four different groups (Bembridae, Platycephalidae, Hoplichthyidae and Peristediidae with Triglidae). Within Cottoidei, Liparidae and Cyclopteridae formed a clade associated with Cottidae, the genus Cottunculus (Psychrolutidae), and Agonidae. Serranidae and Scorpaenidae are not monophyletic, with the Serranidae divided in two clades (Serraninae and Epinephelinae/Anthiinae) and Scorpaenidae including Caracanthidae and the genus Ebinania (Psychrolutidae). We discuss some morphological characters supporting clades within the Scorpaenidae.
ISSN: 1055-7903

hal-01544909
https://hal.archives-ouvertes.fr/hal-01544909
DOI : 10.1016/j.ympev.2012.12.020

Éditeur(s) : HAL CCSD
Résumé : International audience
Ctenophores are non-bilaterian metazoans of uncertain phylogenetic position, some recent studies placing them as sister-group to all other animals whereas others suggest this placement is artefactual and ctenophores are more closely allied with cnidarians and bilaterians, with which they share nerve cells, muscles and gut. Available information about developmental genes and their expression and function in ctenophores is reviewed. These data not only unveil some conserved aspects of molecular developmental mechanisms with other basal metazoan lineages, but also can be expected to enlighten the genomic and molecular bases of the evolution of ctenophore-specific traits, including their unique embryonic development, complex anatomy and high cell type diversity.
ISSN: 0959437X

hal-01509720
http://hal.upmc.fr/hal-01509720
ARXIV : 1605.05876
DOI : 10.1016/j.gde.2016.05.020

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
The common endosymbiotic Wolbachia bacteria influence arthropod hosts in multiple ways. They are mostly recognized for their manipulations of host reproduction, yet, more recent studies demonstrate that Wolbachia also impact host behavior, metabolic pathways and immunity. Besides their biological and evolutionary roles Wolbachia are new potential biological control agents for pest and vector management. Importantly, Wolbachia-based control strategies require controlled symbiont transfer between host species and predictable outcomes of novel Wolbachia-host associations. Theoretically, this artificial horizontal transfer could inflict genetic changes within transferred Wolbachia populations. This could be facilitated through de novo mutations in the novel recipient host or changes of haplotype frequencies of polymorphic Wolbachia populations when transferred from donor to recipient hosts. Here we show that Wolbachia resident in the European cherry fruit fly, Rhagoletis cerasi, exhibit ancestral and cryptic sequence polymorphism in three symbiont genes, which are exposed upon microinjection into the new hosts Drosophila simulans and Ceratitis capitata. Our analyses of Wolbachia in microinjected D. simulans over 150 generations after microinjection uncovered infections with multiple Wolbachia strains in trans-infected lines that had previously been typed as single infections. This confirms the persistence of low-titer Wolbachia strains in microinjection experiments that had previously escaped standard detection techniques. Our study demonstrates that infections by multiple Wolbachia strains can shift in prevalence after artificial host transfer driven by either stochastic or selective processes. Trans-infection of Wolbachia can claim fitness costs in new hosts and we speculate that these costs may have driven the shifts of Wolbachia strains that we saw in our model system.
ISSN: 1932-6203

hal-01544765
https://hal.archives-ouvertes.fr/hal-01544765
DOI : 10.1371/journal.pone.0082402

Éditeur(s) : HAL CCSD Frontiers Media
Résumé : The disease, Heartwater, caused by the Anaplasmataceae E. ruminantium, represents a major problem for tropical livestock and wild ruminants. Up to now, no effective vaccine has been available due to a limited cross protection of vaccinal strains on field strains and a high genetic diversity of Ehrlichia ruminantium within geographical locations. To address this issue, we inferred the genetic diversity and population structure of 194 E. ruminantium isolates circulating worldwide using Multilocus Sequence Typing based on lipA, lipB, secY, sodB, and sucA genes. Phylogenetic trees and networks were generated using BEAST and SplitsTree, respectively, and recombination between the different genetic groups was tested using the PHI test for recombination. Our study reveals the repeated occurrence of recombination between E. ruminantium strains, suggesting that it may occur frequently in the genome and has likely played an important role in the maintenance of genetic diversity and the evolution of E. ruminantium. Despite the unclear phylogeny and phylogeography, E. ruminantium isolates are clustered into two main groups: Group 1 (West Africa) and a Group 2 (worldwide) which is represented by West, East, and Southern Africa, Indian Ocean, and Caribbean strains. Some sequence types are common between West Africa and Caribbean and between Southern Africa and Indian Ocean strains. These common sequence types highlight two main introduction events due to the movement of cattle: from West Africa to Caribbean and from Southern Africa to the Indian Ocean islands. Due to the long branch lengths between Group 1 and Group 2, and the propensity for recombination between these groups, it seems that the West African clusters of Subgroup 2 arrived there more recently than the original divergence of the two groups, possibly with the original waves of domesticated ruminants that spread across the African continent several thousand years ago.
ISSN: 2235-2988

hal-01594501
https://hal.archives-ouvertes.fr/hal-01594501
https://hal.archives-ouvertes.fr/hal-01594501/document
https://hal.archives-ouvertes.fr/hal-01594501/file/paper_MLST_ER_2016_%7B51027B58-C2C7-41C8-9746-BD8A9F387C87%7D.pdf
DOI : 10.3389/fcimb.2016.00111

Éditeur(s) : HAL CCSD
Résumé : International audience
Necroptosis is a regulated form of cell death involved in several disease models including in particular liver diseases. Receptor-interacting protein kinases, RIPK1 and RIPK3, are the main serine/threonine kinases driving this cell death pathway. We screened a noncommercial, kinase-focused chemical library which allowed us to identify Sibiriline as a new inhibitor of necroptosis induced by tumor necrosis factor (TNF) in Fas-associated protein with death domain (FADD)-deficient Jurkat cells. Moreover, Sib inhibits necroptotic cell death induced by various death ligands in human or mouse cells while not protecting from caspase-dependent apoptosis. By using competition binding assay and recombinant kinase assays, we demonstrated that Sib is a rather specific competitive RIPK1 inhibitor. Molecular docking analysis shows that Sib is trapped closed to human RIPK1 adenosine triphosphate-binding site in a relatively hydrophobic pocket locking RIPK1 in an inactive conformation. In agreement with its RIPK1 inhibitory property, Sib inhibits both TNF-induced RIPK1-dependent necroptosis and RIPK1-dependent apoptosis. Finally, Sib protects mice from concanavalin A-induced hepatitis. These results reveal the small-molecule Sib as a new RIPK1 inhibitor potentially of interest for the treatment of immune-dependent hepatitis. © 2017 Federation of European Biochemical Societies
ISSN: 1742464X

hal-01616420
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01616420
DOI : 10.1111/febs.14176
PUBMED : 28715128

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Saccharomyces cerevisiae is an established model organism for the molecular analysis of fundamental biological processes. The genomes of numerous strains have been sequenced, and the transcriptome and proteome ofmajor phases during the haploid and diploid yeast life cycle have been determined. However, much less is known about dynamic changes of the proteome when cells switch from mitotic growth to meiotic development. We report a quantitative protein profiling analysis of yeast cell division and differentiation based on mass spectrometry. Information about protein levels was integrated with strand-specific tiling array expression data. We identified a total of 2366 proteins in at least one condition, including 175 proteins showing a statistically significant > 5-fold change across the sample set, and 136 proteins detectable in sporulating but not respiring cells. We correlate protein expression patterns with biological processes and molecular function by Gene Ontology term enrichment, chemoprofiling, transcription interference and the formation of double stranded RNAs by overlapping sense/antisense transcripts. Our work provides initial quantitative insight into protein expression in diploid respiring and differentiating yeast cells. Critically, it associates developmentally regulated induction of antisense long noncoding RNAs and double stranded RNAs with fluctuating protein concentrations during growth and development.
ISSN: 1874-3919

hal-01485858
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01485858
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01485858/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01485858/file/Becker%20et%20al.%20-%20The%20protein%20expression%20landscape%20of%20mitosis%20and%20me.pdf
DOI : 10.1016/j.jprot.2016.12.016

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
The Southwest Indian Ocean (SWIO) is a striking marine biodiversity hotspot. Coral reefs in this region host a high proportion of endemics compared to total species richness and they are particularly threatened by human activities. The island archipelagos with their diverse marine habitats constitute a natural laboratory for studying diversification processes. Rocky shores in the SWIO region have remained understudied. This habitat presents a high diversity of molluscs, in particular gastropods. To explore the role of climatic and geological factors in lineage diversification within the genus Nerita, we constructed a new phylogeny with an associated chronogram from two mitochondrial genes [cytochrome oxidase sub-unit 1 and 16S rRNA], combining previously published and new data from eight species sampled throughout the region. All species from the SWIO originated less than 20 Ma ago, their closest extant relatives living in the Indo-Australian Archipelago (IAA). Furthermore, the SWIO clades within species with Indo-Pacific distribution ranges are quite recent, less than 5 Ma. These results suggest that the regional diversification of Nerita is closely linked to tectonic events in the SWIO region. The Reunion mantle plume head reached Earth's surface 67 Ma and has been stable and active since then, generating island archipelagos, some of which are partly below sea level today. Since the Miocene, sea-level fluctuations have intermittently created new rocky shore habitats. These represent ephemeral stepping-stones, which have likely facilitated repeated colonization by intertidal gastropods, like Nerita populations from the IAA, leading to allopatric speciation. This highlights the importance of taking into account past climatic and geological factors when studying diversification of highly dispersive tropical marine species. It also underlines the unique history of the marine biodiversity of the SWIO region.
ISSN: 1932-6203

hal-01185713
https://hal.archives-ouvertes.fr/hal-01185713
https://hal.archives-ouvertes.fr/hal-01185713/document
https://hal.archives-ouvertes.fr/hal-01185713/file/PLoS%20ONE%202014%20Postaire.pdf
DOI : 10.1371/journal.pone.0095040

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Cyanobacteria are ubiquitous microorganisms considered as important contributors to the formation of Earth's atmosphere and nitrogen fixation. However, they are also frequently associated with toxic blooms. Indeed, the wide range of hepatotoxins, neurotoxins and dermatotoxins synthesized by these bacteria is a growing environmental and public health concern. This paper provides a state of the art on the occurrence and management of harmful cyanobacterial blooms in surface and drinking water, including economic impacts and research needs. Cyanobacterial blooms usually occur according to a combination of environmental factors e.g., nutrient concentration, water temperature, light intensity, salinity, water movement, stagnation and residence time, as well as several other variables. These environmental variables, in turn, have promoted the evolution and biosynthesis of strain-specific, gene-controlled metabolites (cyanotoxins) that are often harmful to aquatic and terrestrial life, including humans. Cyanotoxins are primarily produced intracellularly during the exponential growth phase. Release of toxins into water can occur during cell death or senescence but can also be due to evolutionary-derived or environmentally-mediated circumstances such as allelopathy or relatively sudden nutrient limitation. Consequently, when cyanobacterial blooms occur in drinking water resources, treatment has to remove both cyanobacteria (avoiding cell lysis and subsequent toxin release) and aqueous cyanotoxins previously released. Cells are usually removed with limited lysis by physical processes such as clarification or membrane filtration. However, aqueous toxins are usually removed by both physical retention, through adsorption on activated carbon or reverse osmosis, and chemical oxidation, through ozonation or chlorination. While the efficient oxidation of the more common cyanotoxins (microcystin, cylindrospermopsin, anatoxin and saxitoxin) has been extensively reported, the chemical and toxicological characterization of their by-products requires further investigation. In addition, future research should also investigate the removal of poorly considered cyanotoxins (β-methylamino-alanine, lyngbyatoxin or aplysiatoxin) as well as the economic impact of blooms.
Environment International

hal-00875835
https://hal-univ-rennes1.archives-ouvertes.fr/hal-00875835
https://hal-univ-rennes1.archives-ouvertes.fr/hal-00875835/document
DOI : 10.1016/j.envint.2013.06.013
PUBMED : 23892224

Éditeur(s) : HAL CCSD
Résumé : National audience
Introduction Une exposition domiciliaire fongique élevée quantifiée par l’index environnemental moléculaire Environmental Relative Moldiness Index (ERMI) est associée au développement de l’asthme dans l’enfance. Dans ce travail, nous avons utilisé cette technique basée sur la quantification moléculaire de 36 champignons dans les poussières pour comparer sa valeur dans l’air à la détection par séquençage haut-débit NGS. Matériels et méthodes Des prélèvements de poussière et d’air ont été collectés dans 20 logements étiquetés « moisis » et 20 logements « non moisis » par les méthodes suivantes : 2 m2 de poussières prélevées à l’aide d’un embout Mitest™ positionné sur un aspirateur ; 3 m3 d’air prélevés par le collecteur cyclonique Coriolis® (Bertin Technologies, France). Tout d’abord, nous avons validé l’ERMI dans l’air versus les poussières, puis comparé dans les prélèvements d’air l’ERMI le séquençage NGS (10 échantillons « moisis » versus 10 échantillons « non moisis »). La cible était le gène 18S séquencé par pyroséquençage à l’aide du système Roche 454. Résultats et discussion Une corrélation entre l’ERMI « poussières » et l’ERMI « air » a été observée avec une valeur significative du test Kendall's tau. Les moisissures intérieures les plus identifiées étaient Aspergillus restrictus, A. fumigatus, A. versicolor, Aureobasidium pullulans Penicillium crustosum, Wallemia sebi, auxquelles s’associaient des moisissures classiquement d’extérieur, Cladosporium cladosporoides, Cladosporium herbarum. L’analyse des séquences obtenues par pyroséquençage était superposable à l’observation par ERMI. Les 3 genres les plus représentés dans l’air intérieur étaient Aspergillus, Penicillium et Cladosporium. Toutefois, quelques genres non inclus dans le panel ont pu être détectés en quantité non négligeable, à l’image des levures notamment du genre Cryptococcus. L’ERMI et le NGS apparaissent donc utiles et corrélés pour la quantification de la charge fongique environnementale dans l’air. L’ERMI a l’avantage d’être une technique rapide, mais sa limite est de cibler a priori 36 genres fongiques (définis initialement aux États-Unis). L’analyse NGS permet d’identifier d’autres genres potentiellement pertinents et donc d’adapter les cibles pour un ERMI « français »
Congrès de la SFMM
Talence-Bordeaux, France

hal-01198651
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01198651
DOI : 10.1016/j.mycmed.2015.06.013

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Abstract View references (35)La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) hollow fibres were prepared by a phase inversion/sintering method using polyetherimide as a binder. In order to overcome surface exchange kinetics limitation, LSCF hollow fibres were coated with ∼200nm palladium (Pd) nanoparticles. The O2 flux of best performing membranes increased by up to 350% in comparison to unmodified LSCF hollow fibres. Optimal enhancement was achieved with a single Pd coating. Additional coatings resulted in reduced O2 fluxes, thus counter acting the beneficial spill-over effect of the catalyst. Long term stability testing in atmospheric air at 850°C showed that a LSCF membrane modified with a single Pd coating continually outperformed a pure LSCF hollow fibre for over 400h, though the level of enhancement was reduced over time. A dramatic reduction in performance of more than 45% occurred within the first 24h of testing, which was attributed to the coalescence and aggregation of Pd catalyst particles to ∼1000nm size at the LSCF grain boundaries. This greatly reduced the available area for the oxygen species to spill-over onto the LSCF surface and thus reduced the overall O2 flux. © 2011 Elsevier B.V.
ISSN: 0376-7388

hal-01683196
https://hal.univ-antilles.fr/hal-01683196
DOI : 10.1016/j.memsci.2011.07.008

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
Macrophages (MΦ), well-known to play an important role in immune response, also respond to environmental toxic chemicals such as diesel exhaust particles (DEP). Potential effects of DEPs towards MΦ polarization, a key hall-mark of MΦ physiology, remain however poorly documented. This study was therefore designed to evaluate the effects of a reference DEP extract (DEPe) on human MΦ polarization. Human blood monocytes-derived MΦ were incubated with IFNγ+LPS or IL-4 to obtain M1 and M2 subtypes, respectively; a 24 h exposure of polarizing MΦ to 10 μg/ml DEPe was found to impair expression of some macrophagic M1 and M2 markers, without however overall inhibition of M1 and M2 polarization processes. Notably, DEPe treatment increased the secretion of the M1 marker IL-8 and the M2 marker IL-10 in both MΦ subtypes, whereas it reduced lipopolysaccharide-induced IL-6 and IL-12p40 secretion in M1 MΦ. In M2 MΦ, DEPe exposure led to a reduction of CD200R expression and of CCL17, CCL18 and CCL22 secretion, associated with a lower chemotaxis of CCR4-positive cells. DEPe activated the Nrf2 and AhR pathways and induced expression of their reference target genes such as Hmox-1 and cytochrome P-4501B1 in M1 and M2 MΦ. Nrf2 or AhR silencing through RNA interference prevented DEPe-related down-regulation of IL-6. AhR silencing also inhibited the down-secretion of IL-12p40 and CCL18 in M1- and M2-DEPe-exposed MΦ, respectively. DEPs are therefore likely to alter expression of some M1 and M2 markers in an AhR- and Nrf2-dependent manner; such regulations may contribute to deleterious immune effects of atmospheric DEP.
ISSN: 1932-6203

hal-01122723
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01122723
PUBMED : 25710172
DOI : 10.1371/journal.pone.0116560

Éditeur(s) : HAL CCSD
Résumé : International audience
Hantaviruses' distribution is reassessed after performing a cladistic analysis on 93 strains isolated from rodents, and one used as out-group: Thottapalayam isolated from a shrew. While most hantaviruses found in wild animals were collected in northern Asia, Europe, North America, and South America, only Thottapalayam and Thailand were found in South and Southeastern Asia. Thottapalayam is highly divergent from the other known hantaviruses and may represent the emerging tip of a different lineage. Serological surveys carried out to detect evidence of Hantavirus in human populations revealed positive samples not only in West and Central Africa but also in Thailand, with a first case recently confirmed. This suggests that Hantaan-related viruses may infect humans out of their well-documented range. Thus, if rodents are probably the primary reservoir, other mammals may be involved in the cycle of hantaviruses. Additional work is needed out of the traditional areas where hantaviruses have been recorded. New viruses, different hosts, and different human syndromes may be discovered in the future mainly in Southeastern Asia and in Africa where Muridae rodents are present and highly diversified.
Annals New York Academy of Sciences

ird-00714427
http://hal.ird.fr/ird-00714427
http://hal.ird.fr/ird-00714427/document
DOI : 10.1196/annals.1373.004
IRD : fdi:010045640

Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
Clin Microbiol Infect 2012; 18 (Suppl. 4): 4043 Abstract In order to study complex microbial communities and their associated mobile genetic elements, such as the human gut microbiome, evolutionists could explore their genetic diversity with shared sequence networks. In particular, the detection of remarkable structures in gene networks of the gut microbiome could serve to identify important functions within the community, and would ease comparison of data sets from microbiomes of various sources (human, ape, mouse etc.) in a single analysis.
ISSN: 1198-743X

hal-01544804
https://hal.archives-ouvertes.fr/hal-01544804
DOI : 10.1111/j.1469-0691.2012.03856.x

Éditeur(s) : HAL CCSD
Résumé : Subduction is one of the major geodynamical process active during the Earth evolution. The characterization of arc magmas, their evolution through space and time, and the relationship between arc magmatism and continental crust forming processes, constitute the main research topics in petrology and geochemistry since the last three decades. This study focuses on an exhumed portion of the Kohistan Arc (N Pakistan), which is an exceptional ‘in situ' laboratory to study and follow through time the processes active on subduction zones. Based on a pluri-geochemical approach, this study allows unraveling two major issues : 1/ The lack of a cogenetic relationship between the arc root (i.e. ultramafic rocks) and the overlying gabbroic crustal section. The Jijal ultramafic section does not bear a crustal origin and was emplaced at ~117 Ma via a magma-rock reaction between REE-depleted ‘boninite-like' melts and the pre-existing lithospheric mantle with Indian-MORB affinities; 2/ A three-stage geodynamical model covering the arc evolution through ~30 Ma. This model starts with the onset of the subduction followed by the building of the volcanic arc (1st stage). The 2nd stage corresponds to a major thermal event, characterized by abundant magma underplating and by granulitisation of the arc base. Recycling of the residual/cumulative lower crust into the convective asthenospheric mantle was efficient during this stage, and probably related to thermo-mechanical erosion processes. The last stage, between ~95 and 85 Ma, seals the end of the intra-oceanic subduction and corresponds to an “amagmatic” period. This step is followed by a voluminous, but short, magmatic pulse at ~85 Ma, occurring just before the arc-continent collision. At last, this study emphasizes the more mafic composition of the investigated crustal arc section when compared to the bulk continental crust. Nevertheless the arc section composition nicely fits with the lower continental crust average.
Les zones de subduction représentent des zones d'évolution clés dans la compréhension des processus géologiques majeurs actifs sur notre planète. En particulier, la caractérisation et l'évolution des magmas générés dans les zones d'arcs océaniques et la relation entre leur genèse et les processus de croissance crustale sont des axes primordiaux. Cette étude est focalisée sur la portion d'arc océanique exhumée du Kohistan (Nord Pakistan) qui constitue un laboratoire exceptionnel pour appréhender cette problématique. Basée sur une approche géochimique multi-méthodes (éléments majeurs et en trace, isotopes), cette étude a permis d'établir : 1/ l'absence de relation génétique directe entre les roches ultrabasiques de la racine de l'arc et la section crustale sus-jacente. La formation de la séquence ultrabasique de Jijal se produit à ~117 Ma via une réaction de type magma-roche entre des liquides de type boninitique (appauvris en terres rares), et le manteau lithosphérique de type MORB-Indien ; 2/ un modèle géodynamique en trois stades majeurs résumant l'évolution de l'arc océanique et de la subduction sur une période d'environ 30 Ma. Ce modèle débute par l'initiation de la subduction et la formation de l'arc volcanique s.s. (1er stade) ; le 2ème stade correspond à un évènement thermique majeur. Il est représenté par un sous-placage important de magmas et une granulitisation intense de la base de l'arc. Le recyclage de la croûte inférieure cumulative et résiduelle, dans le manteau sous-jacent, se produit durant cette étape vraisemblablement suite à des processus d'érosion thermo-mécanique. Le dernier stade, entre 95 Ma et 85 Ma, scelle la fin du fonctionnement de la zone de subduction et correspond à une période amagmatique suivie par une brève reprise du magmatisme avant la collision de l'arc après 85 Ma. Enfin, une modélisation numérique comparative avec la croûte continentale globale met en évidence la composition significativement plus basique de la croûte de l'arc insulaire du Kohistan. De fortes similitudes sont en revanche observées entre la section d'arc étudiée et la croûte continentale inférieure.
https://tel.archives-ouvertes.fr/tel-00437770

tel-00437770
https://tel.archives-ouvertes.fr/tel-00437770
https://tel.archives-ouvertes.fr/tel-00437770/document
https://tel.archives-ouvertes.fr/tel-00437770/file/thesedhuime.pdf

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
Amelotin (AMTN) is an ameloblast-secreted protein that belongs to the secretory calcium-binding phosphoprotein family, which also includes the enamel matrix proteins amelogenin, ameloblastin and enamelin. Although AMTN is supposed to play an important role in enamel formation, data were long limited to the rodents, in which it is expressed during the maturation stage. Recent comparative studies in sauropsids and amphibians revealed that (i) AMTN was expressed earlier, i.e. as soon as ameloblasts are depositing the enamel matrix, and (ii) AMTN structure was different, a change which mostly resulted from an intraexonic splicing in the large exon 8 of an ancestral mammal. The present study was performed to know whether the differences in AMTN structure and expression in rodents compared to non-mammalian tetrapods dated back to an early ancestral mammal or were acquired later in mammalian evolution. We sequenced, assembled and screened the jaw transcriptome of a neonate opossum Monodelphis domestica, a marsupial. We found two AMTN transcripts. Variant 1, representing 70.8% of AMTN transcripts, displayed the structure known in rodents, whereas variant 2 (29.2%) exhibited the nonmammalian tetrapod structure. Then, we studied AMTN expression during amelogenesis in a neonate specimen. We obtained similar data as those reported in rodents. These findings indicate that more than 180 million years ago, before the divergence of marsupials and placentals, changes occurred in AMTN function and structure. The spatiotemporal expression was delayed to the maturation stage of amelogenesis and the intraexonic splicing gave rise to isoform 1, encoded by variant 1 and lacking the RGD motif. The ancestral isoform 2, housing the RGD, was initially conserved, as demonstrated here in a marsupial, then secondarily lost in the placental lineages. These findings bring new elements towards our understanding of the non-prismatic to prismatic enamel transition that occurred at the onset of mammals.
ISSN: 1932-6203

Droits : http://creativecommons.org/licenses/by/
hal-01233552
https://hal.archives-ouvertes.fr/hal-01233552
https://hal.archives-ouvertes.fr/hal-01233552/document
https://hal.archives-ouvertes.fr/hal-01233552/file/journal.pone.0133314.pdf
DOI : 10.1371/journal.pone.0133314