Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Dietary exposure to pesticide residues may present a risk to public health, especially for sensitive populations such as pregnant women. To characterize this risk, this study assessed chronic dietary exposure to pesticide residues based on the French ELFE cohort. A self-administered food frequency questionnaire (FFQ) about the last three months of pregnancy filled in by pregnant women in 2011 was used in combination with occurrence data from French Total Diet Studies completed by the results of national monitoring programs on pesticide residues in food. The dietary intake of pesticides (μg/kg of body weight/day) was estimated for 14,099 pregnant women with a complete FFQ, for 317 substances under two occurrence scenarios to handle left-censored data: a lower-bound scenario (LB), where undetected results were set to zero, and an upper-bound scenario (UB), where undetected results were set to the detection limit if the substance was expected to be found in food and zero if it was not. The risk was assessed for 284 substances with a toxicological reference value (TRV) and a good coverage level of the diet potentially contributing to pesticide intake. The cumulative risk was also assessed for seven effects on nervous and thyroid systems using the hazard index and the Cumulative Assessment Groups defined by EFSA. Substances with the highest exposure levels under the LB scenario were, in decreasing order, imazalil, piperonyl butoxide, chlorpropham, thiabendazole, iprodione and propargite. Under the LB scenario, only for lindane did women have a statistically significant probability of exceeding the TRV (2.4%). Under the UB scenario, risk could not be excluded for nine other substances. A better management of left-censored data and more sensitive analyses of the main food contributors might help to refine the UB exposure and risk assessments. A statistically significant cumulative risk was found for neurochemical effects related to high intake levels of three organophosphate insecticides (chlorpyrifos, pirimiphos-methyl and dimethoate) mainly detected in fruits and cereals
ISSN: 0160-4120

hal-01319892
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01319892
DOI : 10.1016/j.envint.2016.04.007
PUBMED : 27187793

Éditeur(s) : HAL CCSD American Arachnological Society
Résumé : To obtain a reliable description of spider communities, robust sampling protocols are crucial. However, it remains unclear if descriptions of spider communities in tropical habitats require both day and night sampling. Here we tested whether sampling both day and night in high and low vegetation strata would lead to better diversity estimates of spider communities than sampling at only one period of the day. We determined spider taxonomic diversity in a network of 12 plots in French Guiana along a vegetation gradient. We found high alpha diversity of spiders as expected for a tropical area at every site. We showed strong differences in spider alpha and beta diversity between high and low vegetation strata, while they were similar between day and night sampling. Our results suggest that collecting spiders at only one period is sufficient to describe the diversity of spider communities across land use types in the neotropics.
ISSN: 0161-8202

hal-01535342
https://hal.archives-ouvertes.fr/hal-01535342
PRODINRA : 346667

Éditeur(s) : HAL CCSD Elsevier Masson
Résumé : National audience
Contexte La qualité de l’air ambiant dans les enceintes de transports ferroviaires souterrains (EFS) est caractérisée par des particules en suspension riches en métaux, majoritairement du fer, et en carbone, dont la concentration massique est très supérieure à celle mesurée dans l’air ambiant extérieur aux EFS. Cependant, les risques sanitaires chez les travailleurs des EFS liés aux polluants chimiques de l’air présents dans ces enceintes ferroviaires ont été peu étudiés. Dans ce contexte, l’Anses a été saisie afin de dresser un état des connaissances et réaliser une évaluation des risques sanitaires (ERS) chez les travailleurs des EFS. Méthodes Un groupe de travail pluridisciplinaire a analysé les études publiées jusqu’en décembre 2014 et des données communiquées par les exploitants de transport. L’ERS a porté sur les travailleurs de l’exploitation, l’organisation du transport et des services, et des commerces qui exercent une activité durant les horaires de trafic des rames de voyageurs. L’exposition chronique des travailleurs a été estimée à partir des données de concentration inhalée en particules (PM2,5 et PM10), en éléments métalliques, en carbone, en hydrocarbures aromatiques polycycliques particulaires et en hydrocarbures aromatiques monocycliques, issues d’une campagne transversale de métrologie individuelle de la RATP. Cette exposition estimée a ensuite été comparée à une valeur toxicologique de référence (VTR ajustée, VLEP, NOAECHEC) pour calculer un indicateur de risque. Résultats Les risques sanitaires en lien avec les éléments métalliques évalués individuellement semblent négligeables. Concernant l’exposition chronique aux particules, une inflammation des voies respiratoires et des effets consécutifs à cette inflammation sont probables, sur la base d’un effet démontré par une étude de toxicité aiguë chez l’animal. Par analogie avec les particules de l’air ambiant extérieur, des effets délétères sont attendus sur la santé cardiovasculaire et respiratoire en lien avec l’exposition chronique de ces travailleurs aux particules des EFS. L’ERS présente néanmoins des incertitudes notables compte tenu notamment du corpus d’études épidémiologiques assez peu informatif et de l’absence d’étude toxicologique d’exposition chronique. Conclusion Des effets sanitaires sont attendus en relation avec l’exposition chronique des travailleurs à la pollution de l’air des EFS. Des travaux sont recommandés pour combler les lacunes des connaissances sur la toxicité à long terme des particules de l’air de ces enceintes ferroviaires, mais également sur l’exposition de certaines catégories de travailleurs de la maintenance vraisemblablement plus exposés
ISSN: 1775-8785

hal-01331986
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01331986
DOI : 10.1016/j.admp.2016.03.448
PUBMED : 26334607

Éditeur(s) : HAL CCSD National Academy of Sciences
Résumé : International audience
Diatoms (Bacillariophyta) constitute one of the most diverse and ecologically important groups of phytoplankton. They are considered to be particularly important in nutrient-rich coastal ecosystems and at high latitudes, but considerably less so in the oligotrophic open ocean. The Tara Oceans circumnavigation collected samples from a wide range of oceanic regions using a standardized sampling procedure. Here, a total of similar to 12 million diatom V9-18S ribosomal DNA (rDNA) ribotypes, derived from 293 size-fractionated plankton communities collected at 46 sampling sites across the global ocean euphotic zone, have been analyzed to explore diatom global diversity and community composition. We provide a new estimate of diversity of marine planktonic diatoms at 4,748 operational taxonomic units (OTUs). Based on the total assigned ribotypes, Chaetoceros was the most abundant and diverse genus, followed by Fragilariopsis, Thalassiosira, and Corethron. We found only a few cosmopolitan ribotypes displaying an even distribution across stations and high abundance, many of which could not be assigned with confidence to any known genus. Three distinct communities from South Pacific, Mediterranean, and Southern Ocean waters were identified that share a substantial percentage of ribotypes within them. Sudden drops in diversity were observed at Cape Agulhas, which separates the Indian and Atlantic Oceans, and across the Drake Passage between the Atlantic and Southern Oceans, indicating the importance of these ocean circulation choke points in constraining diatom distribution and diversity. We also observed high diatom diversity in the open ocean, suggesting that diatoms may be more relevant in these oceanic systems than generally considered.
ISSN: 0027-8424

hal-01545320
https://hal.archives-ouvertes.fr/hal-01545320
DOI : 10.1073/pnas.1509523113

Éditeur(s) : HAL CCSD BioMed Central
Résumé : International audience
Background: Myosin II (or Myosin Heavy Chain II, MHCII) is a family of molecular motors involved in the contractile activity of animal muscle cells but also in various other cellular processes in non-muscle cells. Previous phylogenetic analyses of bilaterian MHCII genes identified two main clades associated respectively with smooth/non-muscle cells (MHCIIa) and striated muscle cells (MHCIIb). Muscle cells are generally thought to have originated only once in ancient animal history, and decisive insights about their early evolution are expected to come from expression studies of Myosin II genes in the two non-bilaterian phyla that possess muscles, the Cnidaria and Ctenophora. Results: We have uncovered three MHCII paralogues in the ctenophore species Pleurobrachia pileus. Phylogenetic analyses indicate that the MHCIIa /MHCIIb duplication is more ancient than the divergence between extant metazoan lineages. The ctenophore MHCIIa gene (PpiMHCIIa) has an expression pattern akin to that of ``stem cell markers'' (Piwi, Vasa...) and is expressed in proliferating cells. We identified two MHCIIb genes that originated from a ctenophore-specific duplication. PpiMHCIIb1 represents the exclusively muscular form of myosin II in ctenophore, while PpiMHCIIb2 is expressed in non-muscle cells of various types. In parallel, our phalloidin staining and TEM observations highlight the structural complexity of ctenophore musculature and emphasize the experimental interest of the ctenophore tentacle root, in which myogenesis is spatially ordered and strikingly similar to striated muscle formation in vertebrates. Conclusion: MHCIIa expression in putative stem cells/proliferating cells probably represents an ancestral trait, while specific involvement of some MHCIIa genes in smooth muscle fibres is a uniquely derived feature of the vertebrates. That one ctenophore MHCIIb paralogue (PpiMHCIIb2) has retained MHCIIa-like expression features furthermore suggests that muscular expression of the other paralogue, PpiMHCIIb1, was the result of neofunctionalisation within the ctenophore lineage, making independent origin of ctenophore muscle cells a likely option.
ISSN: 1471-2148

hal-01544486
https://hal.archives-ouvertes.fr/hal-01544486
DOI : 10.1186/1471-2148-12-107

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
During their immature life stages, malaria mosquitoes are exposed to a wide array of microbes and contaminants from the aquatic habitats. Although prior studies have suggested that environmental exposure shapes the microbial community structure in the adult mosquito, most reports have focused on laboratory-based experiments and on a single mosquito epithelium, the gut. In this study, we investigated the influence of the breeding site on the development of the Anopheles coluzzii and Anopheles gambiae microbiota in natural conditions. We characterized bacterial communities from aquatic habitats, at surface microlayer and subsurface water levels, to freshly emerge adult mosquitoes using multiplexed 16S rRNA gene pyrosequencing and we separately analyzed the microbiota associated with the different epithelia of adult individual, midguts, ovaries and salivary glands. We found that the distribution of bacterial communities in the aquatic habitats differed according to the depth of water collections. Inter-individual variation of bacterial composition was large in larvae guts but adult mosquitoes from a same breeding site shared quite similar microbiota. Although some differences in bacterial abundances were highlighted between the different epithelia of freshly emerged An. coluzzii and An. gambiae, an intriguing feature from our study is the particular similarity of the overall bacterial communities. Our results call for further investigations on the bacterial population dynamics in the different tissues to determine the distinctive characteristics of each microbiota during the mosquito lifespan and to identify specific interactions between certain key phyla or species and the insect life history traits.
ISSN: 1567-1348

hal-01546167
https://hal.archives-ouvertes.fr/hal-01546167
DOI : 10.1016/j.meegid.2014.09.029

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : We examined tree-soil habitat associations in lowland forest communities at Paracou, French Guiana. We analyzed a large dataset assembling six permanent plots totaling 37.5 ha, in which extensive LIDAR-derived topographical data and soil chemical and physical data have been integrated with precise botanical determinations. Map of relative elevation from the nearest stream summarized both soil fertility and hydromorphic characteristics, with seasonally inundated bottomlands having higher soil phosphate content and base saturation, and plateaus having higher soil carbon, nitrogen and aluminum contents. We employed a statistical test of correlations between tree species density and environmental maps, by generating Monte Carlo simulations of random raster images that preserve autocorrelation of the original maps. Nearly three fourths of the 94 taxa with at least one stem per ha showed a significant correlation between tree density and relative elevation, revealing contrasted species-habitat associations in term of abundance, with seasonally inundated bottomlands (24.5% of species) and well-drained plateaus (48.9% of species). We also observed species preferences for environments with or without steep slopes (13.8% and 10.6%, respectively). We observed that closely-related species were frequently associated with different soil habitats in this region (70% of the 14 genera with congeneric species that have a significant association test) suggesting species-habitat associations have arisen multiple times in this tree community. We also tested if species with similar habitat preferences shared functional strategies. We found that seasonally inundated forest specialists tended to have smaller stature (maximum diameter) than species found on plateaus. Our results underline the importance of tree-soil habitat associations in structuring diverse communities at fine spatial scales and suggest that additional studies are needed to disentangle community assembly mechanisms related to dispersal limitation, biotic interactions and environmental filtering from species-habitat associations. Moreover, they provide a framework to generalize across tropical forest sites.
ISSN: 1932-6203

hal-01260289
https://hal.archives-ouvertes.fr/hal-01260289
PRODINRA : 342930
DOI : 10.1371/journal.pone.0141488

Éditeur(s) : HAL CCSD Nature Publishing Group
Résumé : International audience
Most tumors undergo metabolic reprogramming towards glycolysis, the so-called Warburg effect, to support growth and survival. Overexpression of IF1, the physiological inhibitor of the F0F1ATPase, has been related to this phenomenon and appears to be a relevant marker in cancer. Environmental contributions to cancer development are now widely accepted but little is known about the underlying intracellular mechanisms. Among the environmental pollutants humans are commonly exposed to, benzo[a]pyrene (B[a]P), the prototype molecule of polycyclic aromatic hydrocarbons (PAHs), is a well-known human carcinogen. Besides apoptotic signals, B[a]P can also induce survival signals in liver cells, both likely involved in cancer promotion. Our previous works showed that B[a]P elicited a Warburg-like effect, thus favoring cell survival. The present study aimed at further elucidating the molecular mechanisms involved in the B[a]P-induced metabolic reprogramming, by testing the possible involvement of IF1. We presently demonstrate, both in vitro and in vivo, that PAHs, especially B[a]P, strongly increase IF1 expression. Such an increase, which might rely on β2-adrenergic receptor activation, notably participates to the B[a]P-induced glycolytic shift and cell survival in liver cells. By identifying IF1 as a target of PAHs, this study provides new insights about how environmental factors may contribute to related carcinogenesis.
ISSN: 2045-2322

hal-01518808
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01518808
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01518808/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01518808/file/Hardonni%C3%A8re%20et%20al%202017.pdf
DOI : 10.1038/s41598-017-00269-7

Éditeur(s) : HAL CCSD BioMed Central
Résumé : International audience
The nine countries sharing the Amazon forest accounted for 89% of all malaria cases reported in the Americas in 2008. Remote sensing can help identify the environmental determinants of malaria transmission and their temporo-spatial evolution. Seventeen studies characterizing land cover or land use features, and relating them to malaria in the Amazon subregion, were identified. These were reviewed in order to improve the understanding of the land cover/use class roles in malaria transmission. The indicators affecting the transmission risk were summarized in terms of temporal components, landscape fragmentation and anthropic pressure. This review helps to define a framework for future studies aiming to characterize and monitor malaria.
ISSN: 1475-2875

inserm-00834790
http://www.hal.inserm.fr/inserm-00834790
http://www.hal.inserm.fr/inserm-00834790/document
http://www.hal.inserm.fr/inserm-00834790/file/1475-2875-12-192.pdf
DOI : 10.1186/1475-2875-12-192

Éditeur(s) : HAL CCSD Wiley/Blackwell
Résumé : International audience
Microsatellites are widely used in population genetics to uncover recent evolutionary events. They are typically genotyped using capillary sequencer, which capacity is usually limited to 9, at most 12 loci for each run, and which analysis is a tedious task that is performed by hand. With the rise of next-generation sequencing (NGS), a much larger number of loci and individuals are available from sequencing: for example, on a single run of a GS Junior, 28 loci from 96 individuals are sequenced with a 30X cover. We have developed an algorithm to automatically and efficiently genotype microsatellites from a collection of reads sorted by individual (e.g. specific PCR amplifications of a locus or a collection of reads that encompass a locus of interest). As the sequencing and the PCR amplification introduce artefactual insertions or deletions, the set of reads from a single microsatellite allele shows several length variants. The algorithm infers, without alignment, the true unknown allele(s) of each individual from the observed distributions of microsatellites length of all individuals. MicNeSs, a python implementation of the algorithm, can be used to genotype any microsatellite locus from any organism and has been tested on 454 pyrosequencing data of several loci from fruit flies (a model species) and red deers (a nonmodel species). Without any parallelization, it automatically genotypes 22 loci from 441 individuals in 11 hours on a standard computer. The comparison of MicNeSs inferences to the standard method shows an excellent agreement, with some differences illustrating the pros and cons of both methods.
ISSN: 1755-098X

hal-01544754
https://hal.archives-ouvertes.fr/hal-01544754
DOI : 10.1111/1755-0998.12467

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.
ISSN: 1475-9276

inserm-00809310
http://www.hal.inserm.fr/inserm-00809310
http://www.hal.inserm.fr/inserm-00809310/document
http://www.hal.inserm.fr/inserm-00809310/file/1475-9276-12-21.pdf
DOI : 10.1186/1475-9276-12-21

Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
Two genome-wide association studies (GWASs) recently highlighted the HLA-DRA and HLA-DRB5 genes as associated with Parkinson disease (PD). However, because HLA-DRA displays a low level of polymorphisms and HLA-DRB5 is only present in approximately 20% of the population, these findings are difficult to interpret. Our aims were: (1) to replicate and investigate in greater detail the association between PD and the HLA-DR region; (2) to identify PD-associated HLA alleles; and (3) to perform a meta-analysis of our top finding. As part of 2 French population-based case-control studies of PD including highly ethnically homogeneous participants, we investigated the association between PD and 51 Single-nucleotide polymorphisms (SNPs) in the HLA-DR region. HLA-DRB1 alleles were imputed using the HLA(*) IMP software. HLA typing was performed in a subsample of the participants. We performed a meta-analysis of our top finding based on 4 GWAS data sets. Among 499 cases and 1123 controls, after correction for multiple testing, we found an association with rs660895 (OR/minor allele, 0.70; 95% CI, 0.57-0.87) within the HLA-DRB1 gene, which encodes the most polymorphic HLA-DR chain (DRβ). A meta-analysis (7996 cases, 36455 controls) confirmed this association (OR, 0.86; 95% CI, 0.82-0.91; P < .0001). SNP-based imputation of HLA alleles showed an inverse association between PD and the HLA-DRB1(*) 04 allele. We replicated an association between PD and the HLA-DR region and provided further insight into the loci and alleles involved. The highly polymorphic HLA-DRB1 locus contains rs660895, which represents a more legitimate candidate than previous ones. Our finding is in agreement with the hypothesis of an immune component in PD pathophysiology. © 2012 Movement Disorder Society.
ISSN: 0885-3185

inserm-00721562
http://www.hal.inserm.fr/inserm-00721562
http://www.hal.inserm.fr/inserm-00721562/document
http://www.hal.inserm.fr/inserm-00721562/file/Table1.pdf
http://www.hal.inserm.fr/inserm-00721562/file/Table2.pdf

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : International audience
STUDY QUESTION: Do mild analgesics affect the endocrine system of the human adult testis? SUMMARY ANSWER: Mild analgesics induce multiple endocrine disturbances in the human adult testis in vitro. WHAT IS KNOWN ALREADY: Mild analgesics have recently been incriminated as potential endocrine disruptors. Studies of the effects of these widely used molecules on the androgenic status of men are limited and somewhat contradictory. This prompted us to investigate whether these compounds could alter the adult human testicular function. We therefore assessed in parallel the effects of paracetamol, aspirin and indomethacin on organo-cultured adult human testis and on the NCI-H295R steroid-producing human cell line. STUDY DESIGN, SIZE, DURATION: Adult human testis explants or NCI-H295R adrenocortical human cells were cultured with 10(-4) or 10(-5) M paracetamol, aspirin or indomethacin for 24-48 h. The effect of 10(-5) M ketoconazole, used as an anti-androgenic reference molecule, was also assessed. PARTICIPANTS/MATERIALS, SETTING, METHODS: Testes were obtained from prostate cancer patients, who had not received any hormone therapy. The protocol was approved by the local ethics committee of Rennes, France and informed consent was given by the donors. Only testes displaying spermatogenesis, as assessed by transillumination, were used in this study. Hormone levels in the culture media were determined by radioimmunoassay (testosterone, insulin-like factor 3), Enzyme-Linked Immunosorbent Assay (inhibin B) or Enzyme Immunosorbent Assay [prostaglandin (PG) D2, and PGE2]. Tissues were observed and cells counted using classical immunohistochemical methods. MAIN RESULTS AND THE ROLE OF CHANCE: The three mild analgesics caused multiple endocrine disturbances in the adult human testis. This was particularly apparent in the interstitial compartment. Effective doses were in the same range as those measured in blood plasma following standard analgesic treatment. The production of testosterone and insulin-like factor 3 by Leydig cells was altered by exposure to all these drugs. Inhibin B production by Sertoli cells was marginally affected by aspirin only. Our experiments also revealed that mild analgesics display direct anti-PG activity, which varied depending on the drug used, the dose and the duration of exposure. Nevertheless, associations between the alteration of the PG and testosterone profiles were not systematically observed, suggesting that a combination of mechanisms of endocrine disruption is at play. LIMITATIONS, REASONS FOR CAUTION: Our studies were performed in vitro. WIDER IMPLICATIONS OF THE FINDINGS: We provide the first evidence that direct exposure to mild analgesics can result in multiple endocrine disturbances in the human adult testis. Caution, concerning the consumption of mild analgesics by men, should be strengthened, particularly in high-risk population subgroups such as elite athletes.
ISSN: 0268-1161

inserm-00866016
http://www.hal.inserm.fr/inserm-00866016
PUBMED : 23670170
DOI : 10.1093/humrep/det112

Éditeur(s) : HAL CCSD Wiley
Résumé : Wood specific gravity (WSG) is a strong predictor of tree performance across environmental gradients. Yet it remains unclear how anatomical elements linked to different wood functions contribute to variation in WSG in branches and roots across tropical forests. [br/][br/]We examined WSG and wood anatomy in white sand, clay terra firme and seasonally flooded forests in French Guiana, spanning broad environmental gradients found throughout Amazonia. We measured 15 traits relating to branches and small woody roots in 113 species representing the 15 most abundant species in each habitat and representative species from seven monophyletic lineages occurring in all habitats. [br/][br/]Fiber traits appear to be major determinants of WSG, independent of vessel traits, in branches and roots. Fiber traits and branch and root WSG increased from seasonally flooded species to clay terra firme species and lastly to white sand species. Branch and root wood traits were strongly phylogenetically constrained. Lineages differed in wood design, but exhibited similar variation in wood structure across habitats. [br/][br/]We conclude that tropical trees can invest differently in support and transport to respond to environmental conditions. Wind disturbance and drought stress represent significant filters driving tree distribution of Amazonian forests; hence we suggest that biophysical explanations should receive more attention.
ISSN: 0028-646X

hal-01195075
https://hal.archives-ouvertes.fr/hal-01195075
PRODINRA : 269680
PUBMED : 24329812

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : International audience
Persistent organic pollutants have not been conclusively associated with length of gestation or with preterm birth. Chlordecone is an organochlorine pesticide that has been extensively used to control the banana root borer population in the French West Indies. Data from the Timoun Mother-Child Cohort Study conducted in Guadeloupe between 2004 and 2007 were used to examine the associations of chlordecone concentrations in maternal plasma with the length of gestation and the rate preterm birth in 818 pregnant women. Data were analyzed using multivariate linear regression for length of gestation and a Cox model for preterm birth. The median plasma chlordecone concentration was 0.39 µg/L (interquartile range, 0.18-0.83). No correlation was observed with plasma concentrations of p,p'-dichlorodiphenyl dichloroethene (ρ = 0.017) or polychlorinated biphenyl 153 (ρ = -0.016), the other main organochlorine compounds detected. A 1-log10 increase in chlordecone concentration was associated with a decreased length of gestation (-0.27 weeks; 95% confidence interval: -0.50, -0.03) and an increased risk of preterm birth (60%; 95% confidence interval: 10, 130). These associations may result from the estrogen-like and progestin-like properties of chlordecone. These results are of public health relevance because of the prolonged persistence of chlordecone in the environment and the high background rate of preterm births in this population.
ISSN: 0002-9262

hal-01010740
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01010740
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01010740/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01010740/file/Chlordecone%20Exposure%20final.pdf
DOI : 10.1093/aje/kwt313

Éditeur(s) : HAL CCSD American Society of Tropical Medicine and Hygiene
Résumé : International audience
In South America, the presence of the Leishmania RNA virus type 1 (LRV1) was described in Leishmania guyanensis and Leishmania braziliensis strains. The aim of this study was to determine the prevalence distribution of LRV1 in Leishmania isolates in French Guiana given that, in this French overseas department, most Leishmania infections are due to these parasite species. The presence of the virus was observed in 74% of Leishmania spp. isolates, with a highest presence in the internal areas of the country.
ISSN: 0002-9637

pasteur-01583614
https://hal-riip.archives-ouvertes.fr/pasteur-01583614
https://hal-riip.archives-ouvertes.fr/pasteur-01583614/document
https://hal-riip.archives-ouvertes.fr/pasteur-01583614/file/2016%20Ginouves%20et%20al.%20ajtmh.pdf
PUBMED : 26598572

Éditeur(s) : HAL CCSD Wiley Open Access
Résumé : 11 pages
International audience
The loss of regulating agents such as parasites is among the most important changes in biotic interactions experienced by populations established in newly colonized areas. Under a relaxed parasite pressure, individuals investing less in costly immune mechanisms might experience a selective advantage and become successful colonizers as they re-allocate resources to other fitness-related traits. Accordingly, a refinement of the evolution of increased competitive ability (EICA) hypothesis proposed that immunity of invasive populations has evolved toward a reduced investment in innate immunity, the most costly component of immunity, and an increased humoral immunity that is less costly. Biogeographical approaches comparing populations between native and expansion ranges are particularly relevant in exploring this issue, but remain very scarce. We conducted a biogeographical comparison between populations of Spectacled Thrush (Turdus nudigenis) from the native area (South America) and from the expansion range (Caribbean islands). First, we compared haemosporidian prevalence and circulating haptoglobin (an acute-phase protein produced during inflammation). Second, we challenged captive birds from both ranges with Escherichia coli lipopolysaccharides (LPS) and measured postchallenge haptoglobin production and body mass change. Birds from the expansion range showed lower haemosporidian prevalence and lower levels of haptoglobin than birds from the native range. In addition, the inflammation elicited by LPS injection and its associated cost in terms of body mass loss were lower in birds from the expansion range than in birds from the native range. In accordance with the enemy release hypothesis, our results suggest that range expansion is associated with a reduced infection risk. Our study also supports the hypothesis that individuals from newly established populations have evolved mechanisms to dampen the inflammatory response and are in accordance with one prediction of the refined EICA hypothesis, proposed to understand biological invasions.
ISSN: 2045-7758

hal-01403291
https://hal.archives-ouvertes.fr/hal-01403291
DOI : 10.1002/ece3.2486

Éditeur(s) : HAL CCSD American Society of Tropical Medicine and Hygiene
Résumé : International audience
Anti-leishmaniasis drug resistance is a common problem worldwide. The aim of this study was to inventory the general in vitro level of sensitivity of Leishmania isolates circulating in French Guiana and to highlight potential in vitro pentamidine-resistant isolates. This sensitivity study was conducted on 36 patient-promastigote isolates for seven drugs (amphotericin B, azithromycin, fluconazole, meglumine antimoniate, miltefosine, paromomycin, and pentamidine) using the Cell Counting Kit-8 viability test. The IC50 values obtained were heterogeneous. One isolate exhibited high IC50 values for almost all drugs tested. Pentamidine, which is the first-line treatment in French Guiana, showed efficacy at very low doses (mean of 0.0038 μg/mL). The concordance of the in vitro pentamidine results with the patients' clinical outcomes was 94% (K = 0.82).
ISSN: 0002-9637

inserm-01481512
http://www.hal.inserm.fr/inserm-01481512
http://www.hal.inserm.fr/inserm-01481512/document
http://www.hal.inserm.fr/inserm-01481512/file/2017%2C%20Ginouves%20-%20In%20vitro%20sensitivity%20of%20cutaneous%20leishmania.pdf
DOI : 10.4269/ajtmh.16-0373

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : Climate models predict a range of changes in tropical forest regions, including increased average temperatures, decreased total precipitation, reduced soil moisture and alterations in seasonal climate variations. These changes are directly related to the increase in anthropogenic greenhouse gas concentrations, primarily CO2. Assessing seasonal forest growth responses to climate is of utmost importance because woody tissues, produced by photosynthesis from atmospheric CO2, water and light, constitute the main component of carbon sequestration in the forest ecosystem. In this paper, we combine intra-annual tree growth measurements from published tree growth data and the corresponding monthly climate data for 25 pan-tropical forest sites. This meta-analysis is designed to find the shared climate drivers of tree growth and their relative importance across pan-tropical forests in order to improve carbon uptake models in a global change context. Tree growth reveals significant intra-annual seasonality at seasonally dry sites or in wet tropical forests. Of the overall variation in tree growth, 28.7% was explained by the site effect, i.e. the tree growth average per site. The best predictive model included four climate variables: precipitation, solar radiation (estimated with extrasolar radiation reaching the atmosphere), temperature amplitude and relative soil water content. This model explained more than 50% of the tree growth variations across tropical forests. Precipitation and solar radiation are the main seasonal drivers of tree growth, causing 19.8% and 16.3% of the tree growth variations. Both have a significant positive association with tree growth. These findings suggest that forest productivity due to tropical tree growth will be reduced in the future if climate extremes, such as droughts, become more frequent.
ISSN: 1932-6203

hal-01268529
https://hal.archives-ouvertes.fr/hal-01268529
https://hal.archives-ouvertes.fr/hal-01268529/document
https://hal.archives-ouvertes.fr/hal-01268529/file/journal.pone.0092337.PDF
DOI : 10.1371/journal.pone.0092337

Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
The fitness landscapethe mapping between genotypes and fitnessdetermines properties of the process of adaptation. Several small genotypic fitness landscapes have recently been built by selecting a handful of beneficial mutations and measuring fitness of all combinations of these mutations. Here, we generate several testable predictions for the properties of these small genotypic landscapes under Fisher's geometric model of adaptation. When the ancestral strain is far from the fitness optimum, we analytically compute the fitness effect of selected mutations and their epistatic interactions. Epistasis may be negative or positive on average depending on the distance of the ancestral genotype to the optimum and whether mutations were independently selected, or coselected in an adaptive walk. Simulations show that genotypic landscapes built from Fisher's model are very close to an additive landscape when the ancestral strain is far from the optimum. However, when it is close to the optimum, a large diversity of landscape with substantial roughness and sign epistasis emerged. Strikingly, small genotypic landscapes built from several replicate adaptive walks on the same underlying landscape were highly variable, suggesting that several realizations of small genotypic landscapes are needed to gain information about the underlying architecture of the fitness landscape.
ISSN: 0014-3820

hal-01544760
https://hal.archives-ouvertes.fr/hal-01544760
DOI : 10.1111/evo.12545