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Retrospective Modeling of NO2 and PM10 Concentrations over the Lyon Metropolitan Area (France), 1990–2010—Performance Evaluation, Exposure Assessment and Correlation between Pollutants
No full textInternational audienceNumerous cancers develop years after subjects have been exposed to chemical compounds. Thus, environmental epidemiological studies need to accurately reconstruct exposures over long periods. To estimate exposure to NO2 and PM10 concentrations, we modelled ground-level air concentrations, at very fine temporal (1 h) and spatial (10 m) resolutions, over a large European metropolitan area and at subject’s address of a French national cohort, for five different years (1990, 1995, 2000, 2005 and 2010). Model performances were assessed by comparing the annual modelled concentration against monitoring station measurements. As input data, we used background concentrations from a large-scale dispersion model. The relevance of our approach was assessed by comparing results in 2010, with a modelling using monitoring values as background data. The comparison with measurement data showed good performance of the model for the majority of the period, with a performance declined in 1990. Concentrations at the subject’s residence decreased by 45% for PM10 and 38% for NO2. The proportion of subjects exposed above the WHO recommendations declined from 100% to 50% for PM10 and from 79% to 16% for NO2. The results of this study would provide a reference for future models to assess chronic exposures to PM10 and NO2 on a larger scale
EpicPCR 2.0: Technical and Methodological Improvement of a Cutting-Edge Single-Cell Genomic Approach
No full textInternational audienceEpicPCR (Emulsion, Paired Isolation and Concatenation PCR) is a recent single-cell genomic method based on a fusion-PCR allowing us to link a functional sequence of interest to a 16S rRNA gene fragment and use the mass sequencing of the resulting amplicons for taxonomic assignment of the functional sequence-carrying bacteria. Although it is interesting because it presents the highest efficiency for assigning a bacterial host to a marker, epicPCR remains a complex multistage procedure with technical difficulties that may easily impair the approach depth and quality. Here, we described how to adapt epicPCR to new gene targets and environmental matrices while identifying the natural host range of SXT/R391 integrative and conjugative elements in water microbial communities from the Meurthe River (France). We notably show that adding a supplementary PCR step allowed us to increase the amplicon yield and thus the number of reads obtained after sequencing. A comparison of operational taxonomic unit (OTU) identification approaches when using biological and technical replicates demonstrated that, although OTUs can be validated when obtained from three out of three technical replicates, up to now, results obtained from two or three biological replicates give a similar and even a better confidence level in OTU identification, while allowing us to detect poorly represented SXT/R391 hosts in microbial communities
PM10 chemical profile during North African dust episodes over French West Indies
No full textInternational audienceThe French West Indies are periodically affected by North African dust episodes (NADE) resulting in PM10 concentrations exceeding air quality standards. The aim of the present study was to decipher the PM10 chemical profile during NADE over Guadeloupe. PM10 samples were collected daily at a rural site and an urban site during five episodes between April and October in 2017. During these events, the median PM10 mass concentrations were, on average, 2 to 5 times higher than in the post-episode baseline period. Sampled filters were analyzed for their quantification of chemical constituents including carbonaceous fractions (elemental and organic carbon, EC/OC), anions/cations and levoglucosan, 51 elements, and 57 selected organic species. An orthogonal partial least squares discriminant analysis (OPLS-DA) was conducted to identify the specific chemical profile of PM10 during NADE: 16 elements were identified as the most discriminant between the NADE and the control samples with mass concentration levels twice as high during a NADE. Among them, only two (Mn and V) are classified as emerging pollutant while no limit values exist for the other ones. The extensive characterization of the NADE PM10 chemical profile we performed is a key step to assess the chemical exposure of French West Indies populations during such events
Ozone pollution alters olfaction and behavior of pollinators
No full textThis article belongs to the Special Issue Oxidative Stress Response in a Wide Variety of Insect SpeciesInternational audienceConcentration of air pollutants, particularly ozone (O3), has dramatically increased since pre-industrial times in the troposphere. Due to the strong oxidative potential of O3, negative effects on both emission and lifetime in the atmosphere of plant volatile organic compounds (VOCs) have already been highlighted. VOCs alteration by O3 may potentially affect the attraction of pollinators that rely on these chemical signals. Surprisingly, direct effects of O3 on the olfaction and the behavioral response of pollinators have not been investigated so far. We developed a comprehensive experiment under controlled conditions to assess O3 physiological and behavioral effects on two pollinator species, differing in their ecological traits. Using several realistic concentrations of O3 and various exposure times, we investigated the odor antennal detection and the attraction to VOCs present in the floral scents of their associated plants. Our results showed, in both species, a clear effect of exposure to high O3 concentrations on the ability to detect and react to the floral VOCs. These effects depend on the VOC tested and its concentration, and the O3 exposure (concentration and duration) on the pollinator species. Pollination systems may, therefore, be impaired in different ways by increased levels of O3, the effects of which will likely depend on whether the exposure is chronic or, as in this study, punctual, likely causing some pollination systems to be more vulnerable than others. While several studies have already shown the negative impact of O3 on VOCs emission and lifetime in the atmosphere, this study reveals, for the first time, that this impact alters the pollinator detection and behavior. These findings highlight the urgent need to consider air pollution when evaluating threats to pollinators
Risk of seropositivity to Coxiella burnetii in humans living in areas with endemically infected cattle: No way for specific prevention
No full textInternational audienceQ fever, a zoonotic disease caused by Coxiella burnetii, is endemic among cattle in Western France. However, studies assessing the risk of human infection in such areas are lacking to date, while they may provide information about key specific preventive actions which could be advised to the human populations living with or close to cattle. Therefore, we conducted a cross‐sectional study in two departments of Western France during the 2017/18 winter in order to explore possible risk factors for seropositivity among two distinct populations, i) an occupational risk group, that is, the cattle farmers, and ii) the general adult population (approached by blood donors). Sera were collected in 176 cattle farmers and 347 blood donors respectively, and tested for phase I and II antibodies using an indirect immunofluorescence antibody assay. Each participant was asked to fill in a questionnaire containing socio‐demographic characteristics, occupational and non‐occupational risk exposure. Identified risk factors were: in the general population, working in contact with ruminants, comparatively to any other activity (OR = 4.41; 95% CI: [1.59–6.55]); among farmers, managing an itself infected cattle herd (OR = 3.20; 95% CI: [1.59–6.55]). No other controllable risk factor (lifestyle, outdoor activities, proximity to pets and livestock animals, occupational practices) was here evidenced. In areas with endemically infected cattle, human exposure to Coxiella burnetii is to some extent unavoidable. This strengthens the need for physicians' awareness of the symptoms of Q fever and the appropriateness of general biosecurity measures, especially among at‐risk groups living there
Leviers et freins à la participation à une étude d’exposition dans l’électrohypersensibilité
No full textInternational audienceIntroduction : Les personnes rapportant une électrohypersensibilité (EHS) attribuent différents troubles fonctionnels à leur exposition à des champs électromagnétiques (CEM). À ce jour, les résultats des études de provocation ne permettent pas de conclure à une relation de causalité entre les CEM et les symptômes rapportés. Toutefois, ces études souffrent de différentes limites méthodologiques, dont notamment une faible puissance statistique en raison d’un nombre insuffisant de volontaires. But de l’étude : L’objectif de cet article est de présenter les motivations de personnes rapportant une EHS qui ont participé à des ateliers de cocréation dans le développement d’un protocole de provocation qui s’affranchirait des limites des études existantes et permettrait d’améliorer la connaissance de l’EHS. Résultats : Dans une première phase, les participants ont été invités à parler des raisons de (ne pas) participer à de tels protocoles dans le but d’en comprendre les obstacles et les défis. Parmi les leviers, l’amélioration des connaissances et la sensibilisation du corps médical ainsi que la reconnaissance officielle de l’EHS et ses implications revêtent une grande importance. Les participants soulignent également l’intérêt de mieux se connaître et voient l’étude comme une étape dans le développement d’outils thérapeutiques. Parmi les freins, les personnes relèvent des craintes quant à l’indépendance du projet et la neutralité des résultats ainsi que les choix méthodologiques. Certains soulignent également les conséquences du test sur la santé (souffrance) et des aspects sociaux. Conclusions : Nous dégageons les précautions et recommandations dans la mise en place d’un travail collaboratif avec les personnes EHS et dans leur inclusion pérenne dans une étude d’exposition
Transgenerational metabolic disorders and reproduction defects induced by benzo[a]pyrene in Xenopus tropicalis
No full textInternational audienceMetabolic disorders induced by endocrine disruptors (ED) may contribute to amphibian population declines but no transgenerational studies have evaluated this hypothesis. Here we show that Xenopus tropicalis, exposed from the tadpole stage, to the ED benzo[a]pyrene (BaP, 50 ng.L−1) produced F2 progeny with delayed metamorphosis and sexual maturity. At the adult stage, F2–BaP females displayed fatty liver with inflammation, tissue disorganization and metabolomic and transcriptomic signatures typical of nonalcoholic steato-hepatitis (NASH). This phenotype, similar to that observed in F0 and F1 females, was accompanied by a pancreatic insulin secretory defect. Metabolic disrupted F2–BaP females laid eggs with metabolite contents significantly different from the control and these eggs did not produce viable progeny. This study demonstrated that an ED can induce transgenerational disruption of metabolism and population collapse in amphibians under laboratory conditions. These results show that ED benzo[a]pyrene can impact metabolism over multiple generations and support epidemiological studies implicating environmental EDs in metabolic diseases in humans
Retrospective assessment of pregnancy exposure to particulate matter from desert dust on a Caribbean island: could satellite-based aerosol optical thickness be used as an alternative to ground PM10 concentration?
No full textInternational audienceDesert dust transported from the Saharan-Sahel region to the Caribbean Sea is responsible for peak exposures of particulate matter (PM). This study explored the potential added value of satellite aerosol optical thickness (AOT) measurements, compared to the PM concentration at ground level, to retrospectively assess exposure during pregnancy. MAIAC MODIS AOT retrievals in blue band (AOT(470)) were extracted for the French Guadeloupe archipelago. AOT(470) values and PM10 concentrations were averaged over pregnancy for 906 women (2005-2008). Regression modeling was used to examine the AOT(470)-PM10 relationship during pregnancy and test the association between dust exposure estimates and preterm birth. Moderate agreement was shown between mean AOT(470) retrievals and PM10 ground-based measurements during pregnancy (R-2 = 0.289). The magnitude of the association between desert dust exposure and preterm birth tended to be lower using the satellite method compared to the monitor method. The latter remains an acceptable trade-off between epidemiological relevance and exposure misclassification, in areas with few monitoring stations and complex topographical/meteorological conditions, such as tropical islands
Psychosocial factors at work from the job strain model and preventable mortality in France: the STRESSJEM prospective study
No full textInternational audienceThe study aimed to explore the prospective associations between psychosocial factors at work from the job strain model and preventable mortality, including smoking- and alcohol-related mortality as well as external causes of death. The study was based on prospective data and relied on a sample of 1,511,456 individuals for which data on job history, mortality and causes of death were linked over the 1976–2002 period. Exposures were the factors from the job strain model imputed through a job-exposure matrix. Various time-varying measures of exposure were used including current exposure and two measures of cumulative exposure. Preventable mortality was defined using the OECD/Eurostat list of preventable causes of death. The associations between exposures and outcomes were studied using Cox proportional hazards models. Effect modification by gender was also assessed. Over the study period, 57,264 preventable deaths occurred before the age of 75 years. Low decision latitude, low social support, job strain, iso-strain, passive job, and high strain were associated with preventable mortality, and associations of stronger magnitude were found for job strain and isostrain among men. Stronger associations were observed for alcohol-related mortality than for smoking-related mortality and external causes of death. The fractions of preventable mortality attributable to current exposure to job strain and isostrain were significant among men only (5.1% and 3.3%). Psychosocial factors at work from the job strain model may play a role on preventable mortality. Intensifying research and prevention towards the psychosocial work environment may be helpful to reduce risky health-related behaviours and related mortality
Bacterial Long-Range Warfare: Aerial Killing of Legionella pneumophila by Pseudomonas fluorescens
No full textInternational audienceLegionella pneumophila, the causative agent of Legionnaires' disease, is mostly found in man-made water systems and is one of the most closely monitored waterborne pathogens. With the aim of finding natural ways to control waterborne pathogens and thus further reduce the impact of disinfection by-products on human health, some studies have demonstrated the ability of bacteria to kill Legionella through the production of secondary metabolites or antimicrobial compounds. Here, we describe an unexpected growth inhibition of L. pneumophila when exposed to a physically separated strain of Pseudomonas fluorescens, designated as MFE01. Most of the members of the Legionellaceae family are sensitive to the volatile substances emitted by MFE01, unlike other bacteria tested. Using headspace solid-phase microextraction GC-MS strategy, a volatilome comparison revealed that emission of 1-undecene, 2-undecanone, and 2-tridecanone were mainly reduced in a Tn5-transposon mutant unable to inhibit at distance the growth of L. pneumophila strain Lens. We showed that 1-undecene was mainly responsible for the inhibition at distance in vitro, and led to cell lysis in small amounts, as determined by gas chromatography-mass spectrometry (GC-MS). Collectively, our results provide new insights into the mode of action of bacterial volatiles and highlight them as potent anti-Legionella agents to focus research on novel strategies to fight legionellosis.IMPORTANCE Microbial volatile compounds are molecules whose activities are increasingly attracting the attention of researchers. Indeed, they can act as key compounds in long-distance intrakingdom and interkingdom communication, but also as antimicrobials in competition and predation. In fact, most studies to date have focused on their antifungal activities and only a few have reported on their antibacterial properties. Here, we describe that 1-undecene, naturally produced by P. fluorescens, is a volatile with potent activity against bacteria of the genus Legionella. In small amounts, it is capable of inducing cell lysis even when the producing strain is physically separated from the target. This is the first time that such activity is described. This molecule could therefore constitute an efficient compound to counter bacterial pathogens whose treatment may fail, particularly in pulmonary diseases. Indeed, inhalation of these volatiles should be considered as a possible route of therapy in addition to antibiotic treatment.</div