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An association between maternal weight change in the year before pregnancy and infant birth weight: ELFE, a French national birth cohort study
No full textAuthor summaryWhy was this study done? Maternal obesity is associated with macrosomia at birth and long-term health consequences for the offspring. Results from weight-control interventions during pregnancy suggest that it is too late to address obesity consequences once the pregnancy has already started and that more attention should be paid to the preconception period. The impact of maternal weight changes before pregnancy on infant birth weight has not been thoroughly investigated. What did the researchers do and find? We assessed the association between maternal reported weight changes during the year before pregnancy and infant birth weight in the ELFE French national birth cohort. For women with overweight and obesity, weight loss before pregnancy was associated with increased gestational weight gain compared to women with stable weight before pregnancy, which seemed to cancel out an expected reduction of infant birth weight. What do these findings mean? For women with overweight and obesity, weight-control interventions before pregnancy could be beneficial for fetal growth. Health professionals should be aware of a potential weight gain rebound during pregnancy after a weight loss before pregnancy. Further studies are required to understand the role of weight changes in the preconception period in order to refine nutritional prevention messages for women of childbearing age. Background Weight-control interventions in pregnant women with overweight or obesity have limited effectiveness for fetal growth and birth outcomes. Interventions or prevention programs aiming at the pre-pregnancy period should be considered. However, how the woman's weight change before pregnancy affects fetal growth is not known. We investigated the association between weight change over the year before pregnancy and birth weight. Methods and findings We used the inclusion data of 16,395 women from the ELFE French national birth cohort, a nationally representative cohort in which infants were enrolled at birth with their families in 2011. Maternal weight change was self-reported and classified into 3 groups: moderate weight variation or stable weight, weight loss > 5 kg, and weight gain > 5 kg or both weight loss and gain > 5 kg. Multiple linear regression models were used to investigate the association between pre-pregnancy weight change and a birth weight z-score calculated according to the French Audipog reference, adjusted for a large set of maternal characteristics. The analyses were stratified by maternal body mass index (BMI) at conception (= 25 kg/m(2)) and adjusted for BMI within these categories. We used the MacKinnon method to test the mediating effect of gestational weight gain (GWG) on these associations. Mother's mean age was 30.5 years, 87% were born in France, and 26% had overweight or obesity. For women in either BMI category at conception, GWG was more than 2 kg higher, on average, for women with weight loss before pregnancy than for women with stable weight or moderate weight variation. For women with BMI = 25 kg/m(2) at conception, birth weight was not associated with pre-pregnancy weight loss during the year before pregnancy. Mediation analysis revealed that in these women, the direct effect of pre-pregnancy weight loss that would have resulted in a smaller birth weight z-score (beta = -0.11 [95% CI -0.19; -0.03], p = 0.01) was cancelled out by the GWG. The mediating effect of GWG was even higher when weight loss resulted from a restrictive diet in the year before pregnancy. Weight gain before pregnancy was not associated with birth weight. Although we included a large number of women and had extensive data, the only potential cause of pre-pregnancy weight loss that was investigated was dieting for intentional weight loss. We have no information on other potential causes but did however exclude women with a history of pre-pregnancy chronic disease. Another limitation is declaration bias due to self-reported data. Conclusions Health professionals should be aware that GWG may offset the expected effect of weight loss before conception on fetal growth in overweight and obese women. Further studies are required to understand the underlying mechanisms in order to develop weight-control interventions and improve maternal periconceptional health and developmental conditions for the fetus
Population genomics supports clonal reproduction and multiple independent gains and losses of parasitic abilities in the most devastating nematode pest
No full textThe root‐knot nematodes are the most devastating worms to worldwide agriculture with Meloidogyne incognita being the most widely distributed and damaging species. This parasitic and ecological success seems surprising given its supposed obligatory clonal reproduction. Clonal reproduction has been suspected based on cytological observations but, so far, never confirmed by population genomics data. As a species, M. incognita is highly polyphagous with thousands of host plants. However, different M. incognita isolates present distinct and overlapping patterns of host compatibilities. Historically, four “host races” had been defined as a function of ranges of compat‐ible and incompatible plants. In this study, we used population genomics to assess whether (a) reproduction is actually clonal in this species, (b) the host races follow an underlying phylogenetic signal or, rather represent multiple independent transitions,and (c) how genome variations associate with other important biological traits such as the affected crops and geographical distribution. We sequenced the genomes of 11 M. incognita isolates across Brazil that covered the four host races in replicates. By aligning the genomic reads of these isolates to the M. incognita reference genomeassembly, we identified point variations. Analysis of linkage disequilibrium and 4‐gametes test showed no evidence for recombination, corroborating the clonal re ‐production of M. incognita. The few point variations between the isolates showed no significant association with the host races, the geographical origin of the samples, or the crop on which they have been collected. Addition of isolates from other locations around the world confirmed this lack of underlying phylogenetic signal. This suggests multiple gains and losses of parasitic abilities and adaptations to different environ‐ments account for the broad host spectrum and wide geographical distribution of M. incognita and thus to its high economic impact. This surprising adaptability without sex poses both evolutionary and agro‐economic challenges
Suivi des émissions de N2O sur une maquette de sol cultivé en conditions semi-contrôlées
No full textLa compréhension du déterminisme des émissions de N2O, troisième gaz à effet de serre d’origine anthropique, constitue un enjeu environnemental majeur. Ce manuscrit présente les travaux de recherche réalisés dans le cadre d’un stage de Master 2 à l’INRA (Orléans) sur l’étude du lien entre dynamique des émissions de N2O et fonctionnement hydrique d’un sol cultivé fertilisé. Cette étude a été réalisée sur une maquette expérimentale de sol de 10 m², mise en pente sous un simulateur de pluie. Les émissions de N2O ont été mesurées pendant 70 jours en 16 points de la maquette, à l’aide d’une chambre mobile et d’un spectromètre laser SPIRIT. Les variables du sol (substrats azotés, pH, masse volumique, teneur en eau) ont été mesurées en amont, milieu et aval du dispositif au cours de l’expérimentation. Sur toutes les zones, un premier pic d’émission a été observé en réponse à une pluie de 24 mm consécutive à un apport en substrat azoté – deux conditions favorisant la dénitrification -, et un second pic, plus faible, a été observé après une pluie de 8 mm. La dynamique des processus hydriques (écoulements latéraux, accumulation d’eau en bas de pente), explique des émissions plus fortes en aval.Understanding the dynamics of N2O emissions, the third anthropogenic greenhouse gas, is a major environmental issue. This manuscript presents the research work carried out as part of a Master 2 internship at INRA (Orléans). It deals with the analysis of the relationships between N2O emissions dynamics, and hydric functioning of a cultivated and fertilised soil. A 10 m² sloped soil model was installed under a rain simulator. N2O emissions were measured for 70 days at 16 points of the model, using a fast-box chamber and a SPIRIT laser spectrometer. Soil characteristics (nitrogen, pH, bulk density, water content) were measured upstream, mid- and downstream during the experiment. On all points, a first N2O peak was observed after a 24 mm rainfall following a nitrogen application - two conditions favoring denitrification -, and a second but lower peak was observed after a 8 mm rainfall. The dynamics of the water processes (lateral flows, accumulation of water at the bottom of the slope), explains stronger emissions at the downstream position
The RISKSUR EVA tool (Survtool): A tool for the integrated evaluation of animal health surveillance systems
No full textInformation about infectious diseases at the global level relies on effective, efficient and sustainable national and international surveillance systems. Surveillance systems need to be regularly evaluated to ensure their performance, the quality of the data and information provided, as well as to allocate resources efficiently. Currently available frameworks for evaluation of surveillance systems in animal or human health often treat technical, process and socio-economic aspects separately instead of integrating them. The surveillance evaluation (EVA) tool, a support tool for the evaluation of animal health surveillance systems, was developed to provide guidance for integrated evaluation of animal health surveillance including economic evaluation. The tool was developed by international experts in surveillance and evaluation in an iterative process of development, testing and revision taking into account existing frameworks and guidance, scientific literature and expert opinion. The EVA tool encompasses a web interface for users to develop an evaluation plan, a Wiki classroom to provide theoretical information on all required concepts and a generic evaluation work plan to facilitate implementation and reporting of outputs to decision makers. The tool was tested by planning and conducting epidemiological and economic evaluations of surveillance for classical and African swine fever, bovine virus diarrhoea, avian influenza, and Salmonella Dublin in five European countries. These practical applications highlighted the importance of a comprehensive evaluation approach to improve the quality of the evaluation outputs (economic evaluation; multiple attributes assessment) and demonstrated the usefulness of the guidance provided by the EVA tool. At the same time they showed that comprehensive evaluations might be constrained by practical issues (e.g. confidentiality concerns, data availability) and resource scarcity. In the long term, the EVA tool is expected to increase professional evaluation capacity and help optimising animal health surveillance system efficiency and resource allocation for both public and private actors of the surveillance systems
Detection and quantification of allergens in foods and minimum eliciting doses in food-allergic individuals (Thrall)
No full textRisk-based approaches to managing allergens in foods are being developed by the food industry and regulatory authorities to support food-allergic consumers to avoid ingestion of their problem food, especially in relation to the traces of unintended allergens. The application of such approaches requires access to good quality data from clinical studies to support identification of levels of allergens in foods that are generally safe for most food-allergic consumers as well as analytical tools that are able to quantify allergenic food protein. The ThRAll project aims to support the application of risk-based approaches to food-allergen management in two ways. First, a harmonized quantitative MS-based prototype reference method will be developed for the detection of multiple food allergens in standardized incurred food matrices. This will be undertaken for cow’s milk, hen’s egg, peanut, soybean, hazelnut, and almond incurred into two highly processed food matrices, chocolate and broth powder. This activity is complemented by a second objective to support the development and curation of data on oral food challenges, which are used to define thresholds and minimum eliciting doses. This will be achieved through the development of common protocols for collection and curation of data that will be applied to allergenic foods for which there are currently data gaps
Variations de diamètres des arbres, un outil innovant pour caractériser la phénologie ??? - Un cas d'étude d'arbres en ville...
No full textLes tendances des principaux évènements phénologiques observées ces dernières années dans le monde du vivant (débourrement, sénescence, migration, période reproduction et émergence des stades adultes chez les insectes…) interrogent le monde scientifique sur la capacité des espèces concernées à s’adapter à leur nouvel environnement et/ou à migrer pour suivre le déplacement rapide de leur aire climatique. Par ailleurs, devant la multiplicité des réponses des espèces aux changements en cours, la recherche se doit, pour progresser, de disposer de longues séries de données phénologiques, et de métadonnées associées fiables et précises. Pour répondre à ce besoin, un réseau d’observateurs s’est mis en place depuis quelques années afin notamment d’assurer la formation continue des praticiens permettant de limiter l’effet « observateur » des données recueillies. Parallèlement à cela, plusieurs équipes développent actuellement des systèmes d’observation d’évènements phénologiques (caméras, signaux biologiques, observations satellitaires, radiométrie, systèmes de suivi automatiques des insectes et des poissons …)
Genome sequence of pseudomonas sp. strain ST1, isolated fromo Olive (Olea europaea L.) knot galls in croatia
No full textWe report the genome sequence of a Pseudomonas sp. strain isolated from olive knot galls. The genome size is 6.101 Mbp with a G+C content of 58%. A total of 6,137 coding DNA sequences (CDS) were predicted, including 52 tRNA and 4 rRNA genes
Statistical Stability and Spatial Instability in Mapping Forest Tree Species by Comparing 9 Years of Satellite Image Time Series
No full textMapping forest composition using multiseasonal optical time series remains a challenge. Highly contrasted results are reported from one study to another suggesting that drivers of classification errors are still under-explored. We evaluated the performances of single-year Formosat-2 time series to discriminate tree species in temperate forests in France and investigated how predictions vary statistically and spatially across multiple years. Our objective was to better estimate the impact of spatial autocorrelation in the validation data on measurement accuracy and to understand which drivers in the time series are responsible for classification errors. The experiments were based on 10 Formosat-2 image time series irregularly acquired during the seasonal vegetation cycle from 2006 to 2014. Due to lot of clouds in the year 2006, an alternative 2006 time series using only cloud-free images has been added. Thirteen tree species were classified in each single-year dataset based on the Support Vector Machine (SVM) algorithm. The performances were assessed using a spatial leave-one-out cross validation (SLOO-CV) strategy, thereby guaranteeing full independence of the validation samples, and compared with standard non-spatial leave-one-out cross-validation (LOO-CV). The results show relatively close statistical performances from one year to the next despite the differences between the annual time series. Good agreements between years were observed in monospecific tree plantations of broadleaf species versus high disparity in other forests composed of different species. A strong positive bias in the accuracy assessment (up to 0.4 of Overall Accuracy (OA)) was also found when spatial dependence in the validation data was not removed. Using the SLOO-CV approach, the average OA values per year ranged from 0.48 for 2006 to 0.60 for 2013, which satisfactorily represents the spatial instability of species prediction between years
Strong selection pressures maintain divergence on genomic islands in Atlantic cod (Gadus morhua L.) populations
No full textTwo distinct populations have been extensively studied in Atlantic cod (Gadus morhua L.): the Northeast Arctic cod (NEAC) population and the coastal cod (CC) population. The objectives of the current study were to identify genomic islands of divergence and to propose an approach to quantify the strength of selection pressures using whole-genome single nucleotide polymorphism (SNP) data. After applying filtering criteria, information on 93 animals (9 CC individuals, 50 NEAC animals and 34 CC x NEAC crossbred individuals) and 3,123,434 autosomal SNPs were used.
Four genomic islands of divergence were identified on chromosomes 1, 2, 7 and 12, which were mapped accurately based on SNP data and which extended in size from 11 to 18 Mb. These regions differed considerably between the two populations although the differences in the rest of the genome were small due to considerable gene flow between the populations. The estimates of selection pressures showed that natural selection was substantially more important than genetic drift in shaping these genomic islands. Our data confirmed results from earlier publications that suggested that genomic islands are due to chromosomal rearrangements that are under strong selection and reduce recombination between rearranged and non-rearranged segments.
Our findings further support the hypothesis that selection and reduced recombination in genomic islands may promote speciation between these two populations although their habitats overlap considerably and migrations occur between them