Éditeur(s) : HAL CCSD Wiley
Résumé : Sodium, an element which is needed by animals but often toxic in high concentrations to plants, may be deficient and limit animal abundance in inland continental regions, but may be overabundant and limit plant productivity in coastal regions. Here we present data from 50 independent plots (including leaf data from more than 2480 individual trees) showing that leaves in the Amazon basin uptake high amounts of sodium (Na) in a manner more similar to the essential cation potassium (K) than to the toxic cation aluminium (Al). Leaf Na increases linearly with soil Na concentrations, and there is no apparent mechanism for selective exclusion of Na in comparison to K, a key attribute of halophytes. This indicates that the Amazon basin is broadly non-halophytic and increased sodium concentrations in non-halophyte plants often decrease plant productivity. Total Na concentrations are approximate to 10 times higher in coastal regions than inland regions. Such concentration gradients in nutrients may have been reduced in the past because large animals that were abundant in the Pleistocene have been hypothesized to play a large role in reducing nutrient concentration gradients at continental scales. We use a diffusion model and a Na loss rate based on empirical data to estimate that large animals may have moved significant quantities of Na inland away from coastal regions in the Amazon Basin. Therefore, our simple model suggests that large animals may play an important, yet diminishing, role in maintaining the sodium balance of the planet.
ISSN: 0906-7590

hal-01531615
https://hal.archives-ouvertes.fr/hal-01531615
PRODINRA : 349612
DOI : 10.1111/ecog.01589

Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
Within the framework of the international field campaign COPS (Convective and Orographically induced Precipitation Study), a large suite of state-of-the-art meteorological instrumentation was operated, partially combined for the first time. This includes networks of in situ and remote-sensing systems such as the Global Positioning System as well as a synergy of multi-wavelength passive and active remote-sensing instruments such as advanced radar and lidar systems. The COPS field phase was performed from 01 June to 31 August 2007 in a low-mountain area in southwestern Germany/eastern France covering the Vosges mountains, the Rhine valley and the Black Forest mountains. The collected dataset covers the entire evolution of convective precipitation events in complex terrain from their initiation, to their development and mature phase until their decay. Eighteen Intensive Observations Periods with 37 operation days and eight additional Special Observations Periods were performed, providing a comprehensive dataset covering different forcing conditions. In this article, an overview of the COPS scientific strategy, the field phase, and its first accomplishments is given. Highlights of the campaign are illustrated with several measurement examples. It is demonstrated that COPS research provides new insight into key processes leading to convection initiation and to the modification of precipitation by orography, in the improvement of quantitative precipitation forecasting by the assimilation of new observations, and in the performance of ensembles of convection-permitting models in complex terrain.
ISSN: 0035-9009

hal-00565513
https://hal.archives-ouvertes.fr/hal-00565513
DOI : 10.1002/qj.752

Éditeur(s) : HAL CCSD Nordic Ecological Society
Résumé : Niche differentiation and ecological filtering are primary ecological processes that shape community assembly, but their relative importance remains poorly understood. Analyses of the distributions of functional traits can provide insight into the community structure generated by these processes. We predicted the trait distributions expected under the ecological processes of niche differentiation and environmental filtering, then tested these predictions with a dataset of 4672 trees located in nine 1-ha plots of tropical rain forest in French Guiana. Five traits related to leaf function (foliar N concentration, chlorophyll content, toughness, tissue density and specific leaf area), and three traits related to stem function (trunk sapwood density, branch sapwood density, and trunk bark thickness), as well as laminar surface area, were measured on every individual tree. There was far more evidence for environmental filtering than for niche differentiation in these forests. Furthermore, we contrasted results from species-mean and individual-level trait values. Analyses that took within-species trait variation into account were far more sensitive indicators of niche differentiation and ecological filtering. Species-mean analyses, by contrast, may underestimate the effects of ecological processes on community assembly. Environmental filtering appeared somewhat more intense on leaf traits than on stem traits, whereas niche differentiation affected neither strongly. By accounting for within-species trait variation, we were able to more properly consider the ecological interactions among individual trees and between individual trees and their environment. In so doing, our results suggest that the ecological processes of niche differentiation and environmental filtering may be more pervasive than previously believed.
ISSN: 0030-1299

hal-01032397
https://hal.archives-ouvertes.fr/hal-01032397
DOI : 10.1111/j.1600-0706.2010.19110.x

Éditeur(s) : HAL CCSD SAGE Publications
Résumé : International audience
: French Guiana is the French territory that is most affected by HIV. AIDS incidence is much higher than in mainland France and sex work seems to be an important driver of the epidemic. The objective of this study was to describe consistent condom use among female sex workers with their clients and their intimate partners and to identify determinants of non-use of condoms. An HIV/AIDS Knowledge, Attitudes, Behaviours and Practices survey was conducted in 2009-2010 among sex workers in French Guiana. A total of 477 sex workers were interviewed. Female sex workers were more likely to use condoms with their clients (97%) than with their intimate partners (45%). The factors associated with non-consistent condom use with the intimate partner were having had an abortion, feeling at risk for HIV, not evaluating one's own risk for HIV, living as a couple, being Dominican, not feeling comfortable asking intimate partners to use condoms. Although a high proportion of female sex workers declared using condoms with commercial partners, there is still room for improvement in the prevention of transmission with both commercial and intimate partners.
ISSN: 0956-4624

inserm-01065111
http://www.hal.inserm.fr/inserm-01065111
http://www.hal.inserm.fr/inserm-01065111/document
http://www.hal.inserm.fr/inserm-01065111/file/Table_III_IJSA.pdf
http://www.hal.inserm.fr/inserm-01065111/file/2014_Parriault_-_Predictive_factorssur unprotected_sex_for_female_sex_workers.pdf

Éditeur(s) : HAL CCSD BioMed Central
Résumé : International audience
Introduction In order to study social health inequalities, contextual (or ecologic) data may constitute an appropriate alternative to individual socioeconomic characteristics. Indices can be used to summarize the multiple dimensions of the neighborhood socioeconomic status. This work proposes a statistical procedure to create a neighborhood socioeconomic index. Methods The study setting is composed of three French urban areas. Socioeconomic data at the census block scale come from the 1999 census. Successive principal components analyses are used to select variables and create the index. Both metropolitan area-specific and global indices are tested and compared. Socioeconomic categories are drawn with hierarchical clustering as a reference to determine "optimal" thresholds able to create categories along a one-dimensional index. Results Among the twenty variables finally selected in the index, 15 are common to the three metropolitan areas. The index explains at least 57% of the variance of these variables in each metropolitan area, with a contribution of more than 80% of the 15 common variables. Conclusions The proposed procedure is statistically justified and robust. It can be applied to multiple geographical areas or socioeconomic variables and provides meaningful information to public health bodies. We highlight the importance of the classification method. We propose an R package in order to use this procedure.
International Journal for Equity in Health

hal-00854028
https://hal.archives-ouvertes.fr/hal-00854028
https://hal.archives-ouvertes.fr/hal-00854028/document
DOI : 10.1186/1475-9276-12-21

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
The cyp19a1 gene that encodes aromatase, the only enzyme permitting conversion of C19 aromatizable androgens into estrogens, is present as a single copy in the genome of most vertebrate species, except in teleosts in which it has been duplicated. This study aimed at investigating the brain expression of a cyp19a1 gene expressed in both gonad and brain of Japanese eel, a basal teleost. By means of immunohistochemistry and in situ hybridization, we show that cyp19a1 is expressed only in radial glial cells of the brain and in pituitary cells. Treatments with salmon pituitary homogenates (female) or human chorionic gonadotrophin (male), known to turn on steroid production in immature eels, strongly stimulated cyp19a1 messenger and protein expression in radial glial cells and pituitary cells. Using double staining studies, we also showed that aromatase-expressing radial glial cells exhibit proliferative activity in both the brain and the pituitary. Altogether, these data indicate that brain and pituitary expression of Japanese eel cyp19a1 exhibits characteristics similar to those reported for the brain specific cyp19a1b gene in teleosts having duplicated cyp19a1 genes. This supports the hypothesis that, despite the fact that eels also underwent the teleost specific genome duplication, they have a single cyp19a1 expressed in both brain and gonad. Such data also suggest that the intriguing features of brain aromatase expression in teleost fishes were not gained after the whole genome duplication and may reflect properties of the cyp19a1 gene of ancestral Actinopterygians.
ISSN: 1932-6203

hal-00877375
https://hal.archives-ouvertes.fr/hal-00877375
https://hal.archives-ouvertes.fr/hal-00877375/document
https://hal.archives-ouvertes.fr/hal-00877375/file/Expressionsur Aromatase-accepted.pdf
DOI : 10.1371/journal.pone.0044750

Éditeur(s) : HAL CCSD LIPPINCOTT WILLIAMS & WILKINS Lippincott, Williams & Wilkins
Résumé : International audience
Psychosomatic Medicine
Miami, United States

hal-00955340
https://hal-univ-rennes1.archives-ouvertes.fr/hal-00955340

Éditeur(s) : HAL CCSD Wiley/Blackwell
Résumé : Whole genome sequencing is helping generate robust phylogenetic hypotheses for a range of taxonomic groups that were previously recalcitrant to classical molecular phylogenetic approaches. As a case study, we performed a shallow shotgun sequencing of eight species in the tropical tree family Chrysobalanaceae to retrieve large fragments of high-copy number DNA regions and test the potential of these regions for phylogeny reconstruction. We were able to assemble the nuclear ribosomal cluster (nrDNA), the complete plastid genome (ptDNA) and a large fraction of the mitochondrial genome (mtDNA) with approximately 1000x, 450x and 120x sequencing depth respectively. The phylogenetic tree obtained with ptDNA resolved five of the seven internal nodes. In contrast, the tree obtained with mtDNA and nrDNA data were largely unresolved. This study demonstrates that genome skimming is a cost-effective approach and shows potential in plant molecular systematics within Chrysobalanaceae and other under-studied groups.
ISSN: 1755-098X

hal-01204217
https://hal.archives-ouvertes.fr/hal-01204217
DOI : 10.1111/1755-0998.12246
PRODINRA : 283530

Éditeur(s) : HAL CCSD Royal Society, The
Résumé : Plant leaf litter generally decomposes faster as a group of different species than when individual species decompose alone, but underlyingmechanisms of these diversity effects remain poorly understood. Because resource C : N: P stoichiometry (i.e. the ratios of these key elements) exhibits strong control on consumers, we supposed that stoichiometric dissimilarity of litter mixtures (i.e. the divergence in C : N: P ratios among species) improves resource complementarity to decomposers leading to faster mixture decomposition. We tested this hypothesis with: (i) a wide range of leaf litter mixtures of neotropical tree species varying in C : N: P dissimilarity, and (ii) a nutrient addition experiment (C, N and P) to create stoichiometric similarity. Litter mixtures decomposed in the field using two different types of litterbags allowing or preventing access to soil fauna. Litter mixture mass loss was higher than expected from species decomposing singly, especially in presence of soil fauna. With fauna, synergistic litter mixture effects increased with increasing stoichiometric dissimilarity of litter mixtures and this positive relationship disappeared with fertilizer addition. Our results indicate that litter stoichiometric dissimilarity drives mixture effects via the nutritional requirements of soil fauna. Incorporating ecological stoichiometry in biodiversity research allows refinement of the underlying mechanisms of how changing biodiversity affects ecosystem functioning.
ISSN: 0962-8452

hal-01204222
https://hal.archives-ouvertes.fr/hal-01204222
DOI : 10.1098/rspb.2014.1682
PRODINRA : 289918

Éditeur(s) : HAL CCSD
Résumé : International audience
In two swordtail species of the genus Xiphophorus, the onset of puberty has been shown to be modulated at the P locus by sequence polymorphism and gene copy-number variation affecting the type 4 melanocortin hormone receptor Mc4r. The system works through the interaction of two allelic types, one encoding wild type and the other dominant-negative receptors. We have analyzed the structure and evolution of the P locus in the platyfish Xiphophorus maculatus, where as many as nine alleles of P determining the onset of sexual maturity in males and females, fecundity in females, and adult size in males are located on both the X and Y chromosomes in a region linked to the master sex-determining locus. In this species, mc4r has been amplified to up to 10 copies on both the X and Y chromosomes through recent large serial duplications. Subsequently, mc4r paralogues have diverged considerably into many different subtypes. Certain copies have acquired new untranslated regions through genomic rearrangements, and transposable element insertions and other mutations have accumulated in promoter regions, possibly explaining observed deviations from the classical mc4r transcriptional pattern. In the mc4r-coding sequence, in-frame insertions and deletions as well as nonsense and missense mutations have generated a high diversity of Mc4r-predicted proteins. Most of these variants are expressed in embryos, adults, and/or tumors. Functional receptor characterization demonstrated major divergence in pharmacological behavior for Mc4r receptors encoded by different copies of platyfish mc4r, with differences in constitutive activity as well as binding and stimulation by hormones. The high degree of allelic and copy-number variation observed between individuals can explain the high level of polymorphism for sexual maturation, fecundity, and body size in the platyfish: multiple combinations of Mc4r variants with different biochemical properties might interact to modulate the melanocortin signaling that regulates the hypothalamus-pituitary-gonadal axis.
GENETICS

hal-01544912
https://hal.archives-ouvertes.fr/hal-01544912
DOI : 10.1534/genetics.113.155952

Éditeur(s) : HAL CCSD Lippincott, Williams & Wilkins
Résumé : International audience
Objectives: Lung cancer risk associated with occupational cleaning activities has been investigated in the population-based case-control study ICARE. Methods: Occupational history was collected by standardized interviews. Jobs were first defined according to the International Standard Classification of Occupations (ISCO) codes and then categorized according to activity sectors. Adjusted odds ratios (ORs) were estimated by unconditional logistic regression, separately for women (619 cases and 760 controls) and men (2265 and 2780). Results: Thirty percent of women and 2.3% of men controls ever held a cleaner or care job. Women who worked as housemaids longer than 7 years showed an OR of 1.76 [95% confidence interval (95% CI) 1.09 to 2.87] with respect to controls. Women employed in domestic service sector for a long time had an OR of 2.06 (95% CI 1.15 to 3.66). Conclusion: We confirmed and redefined the association of lung cancer with occupational cleaning, which concerns a considerable proportion of women workers.
ISSN: 1076-2752

hal-01359564
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01359564
DOI : 10.1097/JOM.0000000000000722
PUBMED : 27206119

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Few studies have explored the consequences of environmental exposure to organochlorine pesticides for gestational hypertension (GH), preeclampsia (PE) and gestational diabetes mellitus (GDM). Chlordecone is a persistent organochlorine pesticide that was used intensively, and almost exclusively, in the French West Indies until 1993. We investigated the impact of prenatal exposure to chlordecone on the occurrence of GDM, GH and PE by studying 779 pregnant women enrolled in a prospective mother-child cohort (Timoun Study) in Guadeloupe between 2004 and 2007. Chlordecone exposure was determined by assaying maternal plasma and information about pregnancy complications was obtained from midwives, pediatricians and hospital medical records after delivery. The risks of GH (n=65), PE (n=31) and GDM (n=71) were estimated by multiple logistic regression including potential confounders. Levels of chlordecone plasma concentration in the third (OR=0.2; 95% confidence interval (CI): 0.1, 0.5) and fourth quartiles (OR=0.3; 95% CI: 0.2, 0.7) were associated with a statistically significant decrease in the risk of GH. A log10 increase in chlordecone concentration was significantly associated with lower risk of GH (OR=0.4; 95% CI: 0.2, 0.6). No significant associations were observed between the chlordecone exposure and the risk of PE or GDM. This study suggests an inverse association between chlordecone exposure during pregnancy and GH. Further studies are required to determine the underlying mechanism, or the potential unknown confounding factors, resulting in this association.
ISSN: 0160-4120

hal-01061391
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01061391
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01061391/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01061391/file/Saunders_et_al._Final_version_main_manuscript.pdf
DOI : 10.1016/j.envint.2014.03.024

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Implication of immune processes in bipolar disorder (BD) has recently gained increasing attention. Tolerogenic molecules, among which HLA-G plays a prominent role, mediate the modulation of such processes. The HLA-G locus is characterized by a high number of polymorphisms including a functionally relevant 14 base pair (bp) insertion/deletion (Ins/Del) allele affecting the HLA-G expression. Here, we analyzed the distribution of this polymorphism in 561 BD patients and 161 healthy and found that the HLA-G 14bp Ins/Ins genotype was significantly more prevalent in healthy controls than in patients (corrected p; pc=0.032) and that the prevalence of such protective genotype is lower among patients born during the winter season as compared to those born in other periods (pc=0.006). Possible mechanisms between low HLA G expression and resistance to infections as well as potential relationships between infections in early life and susceptibility to BD are discussed.
ISSN: 0198-8859

inserm-00864639
http://www.hal.inserm.fr/inserm-00864639
http://www.hal.inserm.fr/inserm-00864639/document
http://www.hal.inserm.fr/inserm-00864639/file/HLA-G_and_BD_manuscript_-1.pdf
DOI : 10.1016/j.humimm.2012.11.032

Éditeur(s) : HAL CCSD Ferrata Storti Foundation
Résumé : International audience
BACKGROUND: Abnormal interactions between red blood cells, leukocytes and endothelial cells play a critical role in the occurrence of the painful vaso-occlusive crises associated with sickle cell disease. We investigated the interaction between circulating leukocytes and red blood cells which could lead to aggregate formation, enhancing the incidence of vaso-occlusive crises. DESIGN AND METHODS: Blood samples from patients with sickle cell disease (n=25) and healthy subjects (n=5) were analyzed by imaging and classical flow cytometry after density gradient separation. The identity of the cells in the peripheral blood mononuclear cell layer was determined using antibodies directed specifically against white (anti-CD45) or red (anti-glycophorin A) blood cells. RESULTS: Aggregates between red blood cells and peripheral blood mononuclear cells were visualized in whole blood from patients with sickle cell disease. The aggregation rate was 10-fold higher in these patients than in control subjects. Both mature red blood cells and reticulocytes were involved in these aggregates through their interaction with mononuclear cells, mainly with monocytes. The size of the aggregates was variable, with one mononuclear cell binding to one, two or several red blood cells. Erythroid Lu/basal cell adhesion molecule and α(4)β(1) integrin were involved in aggregate formation. The aggregation rate was lower in patients treated with hydroxycarbamide than in untreated patients. CONCLUSIONS: Our study gives visual evidence of the existence of circulating red blood cell-peripheral blood mononuclear cell aggregates in patients with sickle cell disease and shows that these aggregates are decreased during hydroxycarbamide treatment. Our results strongly suggest that erythroid Lu/basal cell adhesion molecule proteins are implicated in these aggregates through their interaction with α(4)β(1) integrin on peripheral blood mononuclear cells.
ISSN: 0390-6078

inserm-00821120
http://www.hal.inserm.fr/inserm-00821120
http://www.hal.inserm.fr/inserm-00821120/document
http://www.hal.inserm.fr/inserm-00821120/file/1841.full.pdf
DOI : 10.3324/haematol.2010.026294

Éditeur(s) : HAL CCSD Nature Publishing Group
Résumé : International audience
Among pregnant women ibuprofen is one of the most frequently used pharmaceutical compounds with up to 28% reporting use. Regardless of this, it remains unknown whether ibuprofen could act as an endocrine disruptor as reported for fellow analgesics paracetamol and aspirin. To investigate this, we exposed human fetal testes (7-17 gestational weeks (GW)) to ibuprofen using ex vivo culture and xenograft systems. Ibuprofen suppressed testosterone and Leydig cell hormone INSL3 during culture of 8-9 GW fetal testes with concomitant reduction in expression of the steroidogenic enzymes CYP11A1, CYP17A1 and HSD17B3, and of INSL3. Testosterone was not suppressed in testes from fetuses younger than 8 GW, older than 10-12 GW, or in second trimester xenografted testes (14-17 GW). Ex vivo, ibuprofen also affected Sertoli cell by suppressing AMH production and mRNA expression of AMH, SOX9, DHH, and COL2A1. While PGE2 production was suppressed by ibuprofen, PGD2 production was not. Germ cell transcripts POU5F1, TFAP2C, LIN28A, ALPP and KIT were also reduced by ibuprofen. We conclude that, at concentrations relevant to human exposure and within a particular narrow â €' early window' of sensitivity within first trimester, ibuprofen causes direct endocrine disturbances in the human fetal testis and alteration of the germ cell biology. © The Author(s) 2017.
ISSN: 2045-2322

hal-01517095
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01517095
DOI : 10.1038/srep44184
PUBMED : 28281692

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Long-term exposure to air pollution (AP) has been shown to have an impact on mortality in numerous countries, but since 2005 no data exists for France. We analyzed the association between long-term exposure to air pollution and mortality at the individual level in a large French cohort followed from 1989 to 2013. The study sample consisted of 20,327 adults working at the French national electricity and gas company EDF-GDF. Annual exposure to PM10, PM10–2.5, PM2.5, NO2, O3, SO2, and benzene was assessed for the place of residence of participants using a chemistry-transport model and taking residential history into account. Hazard ratios were estimated using a Cox proportional-hazards regression model, adjusted for selected individual and contextual risk factors. Hazard ratios were computed for an interquartile range (IQR) increase in air pollutant concentrations. The cohort recorded 1967 non-accidental deaths. Long-term exposures to baseline PM2.5, PM10-25, NO2 and benzene were associated with an increase in non-accidental mortality (Hazard Ratio, HR = 1.09; 95% CI: 0.99, 1.20 per 5.9 μg/m3, PM10-25; HR = 1.09; 95% CI: 1.04, 1.15 per 2.2 μg/m3, NO2: HR = 1.14; 95% CI: 0.99, 1.31 per 19.3 μg/m3 and benzene: HR = 1.10; 95% CI: 1.00, 1.22 per 1.7 μg/m3).The strongest association was found for PM10: HR = 1.14; 95% CI: 1.05, 1.25 per 7.8 μg/m3. PM10, PM10-25 and SO2 were associated with non-accidental mortality when using time varying exposure. No significant associations were observed between air pollution and cardiovascular and respiratory mortality. Long-term exposure to fine particles, nitrogen dioxide, sulfur dioxide and benzene is associated with an increased risk of non-accidental mortality in France. Our results strengthen existing evidence that outdoor air pollution is a significant environmental risk factor for mortality. Due to the limited sample size and the nature of our study (occupational), further investigations are needed in France with a larger representative population sample.
ISSN: 0160-4120

hal-01187145
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01187145
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01187145/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01187145/file/Association%20between%20long-term%20exposure%20to%20air%20pollution%20and%20mortality_accepted.pdf
DOI : 10.1016/j.envint.2015.08.006

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : In habitat mosaics, plant populations face environmental heterogeneity over short geographical distances. Such steep environmental gradients can induce ecological divergence. Lowland rainforests of the Guiana Shield are characterized by sharp, short-distance environmental variations related to topography and soil characteristics (from waterlogged bottomlands on hydromorphic soils to well-drained terra firme on ferralitic soils). Continuous plant populations distributed along such gradients are an interesting system to study intrapopulation divergence at highly local scales. This study tested (1) whether conspecific populations growing in different habitats diverge at functional traits, and (2) whether they diverge in the same way as congeneric species having different habitat preferences. Phenotypic differentiation was studied within continuous populations occupying different habitats for two congeneric, sympatric, and ecologically divergent tree species (Eperua falcata and E. grandiflora, Fabaceae). Over 3000 seeds collected from three habitats were germinated and grown in a common garden experiment, and 23 morphological, biomass, resource allocation and physiological traits were measured. In both species, seedling populations native of different habitats displayed phenotypic divergence for several traits (including seedling growth, biomass allocation, leaf chemistry, photosynthesis and carbon isotope composition). This may occur through heritable genetic variation or other maternally inherited effects. For a sub-set of traits, the intraspecific divergence associated with environmental variation coincided with interspecific divergence. The results indicate that mother trees from different habitats transmit divergent trait values to their progeny, and suggest that local environmental variation selects for different trait optima even at a very local spatial scale. Traits for which differentiation within species follows the same pattern as differentiation between species indicate that the same ecological processes underlie intra- and interspecific variation.
ISSN: 0305-7364

hal-01032430
https://hal.archives-ouvertes.fr/hal-01032430
DOI : 10.1093/aob/mct176

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
The susceptibility of Anopheles mosquitoes to Plasmodium infections relies on complex interactions between the insect vector and the malaria parasite. A number of studies have shown that the mosquito innate immune responses play an important role in controlling the malaria infection and that the strength of parasite clearance is under genetic control, but little is known about the influence of environmental factors on the transmission success. We present here evidence that the composition of the vector gut microbiota is one of the major components that determine the outcome of mosquito infections. A. gambiae mosquitoes collected in natural breeding sites from Cameroon were experimentally challenged with a wild P. falciparum isolate, and their gut bacterial content was submitted for pyrosequencing analysis. The meta-taxogenomic approach revealed a broader richness of the midgut bacterial flora than previously described. Unexpectedly, the majority of bacterial species were found in only a small proportion of mosquitoes, and only 20 genera were shared by 80% of individuals. We show that observed differences in gut bacterial flora of adult mosquitoes is a result of breeding in distinct sites, suggesting that the native aquatic source where larvae were grown determines the composition of the midgut microbiota. Importantly, the abundance of Enterobacteriaceae in the mosquito midgut correlates significantly with the Plasmodium infection status. This striking relationship highlights the role of natural gut environment in parasite transmission. Deciphering microbe-pathogen interactions offers new perspectives to control disease transmission.
ISSN: 1553-7366

hal-01546176
https://hal.archives-ouvertes.fr/hal-01546176
DOI : 10.1371/journal.ppat.1002742

Éditeur(s) : HAL CCSD BioMed Central
Résumé : International audience
AbstractBackgroundFew epidemiological studies have investigated the link between occupational exposure to solvents and head and neck cancer risk, and available findings are sparse and inconsistent. The objective of this study was to examine the association between occupational exposure to chlorinated solvents and head and neck cancer risk.MethodsWe analyzed data from 4637 men (1857 cases and 2780 controls) included in a population-based case-control study, ICARE (France). Occupational exposure to five chlorinated solvents (perchloroethylene [PCE], trichloroethylene [TCE], methylene chloride [MC], chloroform [CF], and carbon tetrachloride [CT]) was assessed through job-exposure matrices. Odds ratios (ORs) and confidence intervals (95% CI) were estimated by unconditional logistic regression, adjusted for age, tobacco smoking, alcohol consumption, asbestos exposure, and other potential confounders.ResultsWe observed no association between chlorinated solvent exposure and head and neck cancer risk, despite a non-significant increase in risk among subjects who had the highest cumulative level of exposure to PCE, (OR = 1.81; 95% CI = 0.68 to 4.82). In subsite analysis, the risk of laryngeal cancer increased with cumulative exposure to PCE (p for trend = 0.04). The OR was 3.86 (95% CI = 1.30 to 11.48) for those exposed to the highest levels of PCE. A non-significant elevated risk of hypopharyngeal cancer was also observed in subjects exposed to the highest levels of MC (OR = 2.36; 95% CI = 0.98 to 5.85).ConclusionOur findings provide evidence that high exposure to PCE increases the risk of laryngeal cancer, and suggest an association between exposure to MC and hypopharyngeal cancer. Exposure to other chlorinated solvents was not associated with the risk of head and neck cancer.
ISSN: 1476-069X

inserm-01570445
http://www.hal.inserm.fr/inserm-01570445
http://www.hal.inserm.fr/inserm-01570445/document
http://www.hal.inserm.fr/inserm-01570445/file/12940_2017_Article_286.pdf
http://www.hal.inserm.fr/inserm-01570445/file/12940_2017_286_MOESM1_ESM.pdf

Éditeur(s) : HAL CCSD Wiley
Résumé : 1. Considerable debate surrounds the extent to which tropical forests can be managed for resource extraction while conserving biodiversity and ecosystem properties, which depend on functional composition. Here we evaluate the compatibility of these aims by examining the effects of logging on taxonomic and functional diversity and composition in a tropical forest. 2. Twenty years after selective logging, we inventoried 4140 stems regenerating in logging gaps and adjacent undisturbed areas, and we integrated a database of 13 functional traits describing leaf and wood economics of tropical trees. 3. We found no differences in taxonomic and functional richness among habitats, but logging gaps had significantly higher taxonomic and functional evenness. 4. Logging also effected striking, long-term changes in both species and functional composition. In particular, the xylem density of recruits in logging gaps was 6% less than in unlogged forests, leaves were 11% less tough and had 613% greater mineral nutrient concentrations. 5. Synthesis and applications. Our results suggest that managers of tropical forests should limit overall surface area converted to logging gaps by creating fewer, larger gaps during selective logging, to reduce impacts on the taxonomic and functional composition of the regenerating stand.
ISSN: 0021-8901

hal-01032420
https://hal.archives-ouvertes.fr/hal-01032420
DOI : 10.1111/j.1365-2664.2012.02164.x