HAL du Programme national de recherche environnement-santé-travail (PNR EST)
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The threat is in the details – critical gap in ecotoxicological assessment of Microcystis blooms revealed by critical distinctions of genotype effects induced on Medaka fish
No full textInternational audienceMicrocystis spp., prolific bloom-forming freshwater cyanobacteria, produce a wide range of bioactive secondary metabolites. While microcystins (MCs) are well-characterized hepatotoxins, the ecotoxicological roles of other Microcystis-derived compounds remain poorly understood. This study evaluates the toxic potential of four Microcystis strains -two MC-producing (PMC 728.11, 807.12) and two non-MC-producing (PMC 810.12, 826.12) -in Medaka fish (Oryzias latipes) at different life stages. Embryos and larvae exposed to extracts from non-MCproducing strains exhibited pronounced developmental toxicity and malformations, linked to the presence of microginins, aeruginosins, and microcyclamides. MC-rich strain PMC 728.11 induced significant post-hatch toxicity. In adult females exposed under microcosm conditions to environmentally relevant concentrations, strain-specific disruptions were observed in gut microbiota composition and tissue metabolomes. Notably, PMC 728.11 caused microbial dysbiosis, while PMC 826.12 impaired digestive functions, enhancing susceptibility to toxicant uptake. The remaining strains produced milder effects. Our results demonstrate that Microcystis toxicity extends beyond MCs, driven by complex and variable metabolite mixtures. This biochemical diversity poses challenges for bloom risk assessment and raises concerns over unrecognized environmental hazards. These findings advocate for broader monitoring of cyanobacterial metabolites and their mechanistic impacts in aquatic toxicology and environmental health
Evolutionary ecophysiology in extreme environments under a global change scenario
No full textInternational audienceAs wildlife increasingly has to face levels of environmental conditions that go far beyond normal ranges, understanding the ecological and evolutionary dynamics behind such extreme scenarios becomes essential for animal conservation. Here, we discuss the eco-physiological singularities of wildlife coping with extreme conditions. We first discuss the conditions under which scenarios can be considered 'extreme'. This includes distinguishing the nature of natural and anthropogenic disturbances, considering aspects such as their intensities, as well as the understanding of species biology and evolutionary history. To exemplify the diversity of wildlife responses to extreme conditions, we highlight five different representative study cases (two with natural causes, three of anthropogenic origin): birds at high altitude, fish in geothermal habitats, birds in pesticide-laden farmlands, invertebrates in urban ponds, and amphibians in radioactive zones. These examples illustrate the diverse physiological and ecological responses to extreme factors, emphasizing the complexity of wildlife adaptation under different scenarios. However, they also reveal significant knowledge gaps regarding long-term effects of responses to extreme environments, and the mechanistic basis behind these processes. Future research should ideally include longterm approaches making use of validated physiological markers of individual, population or species health or fitness. This information could be then incorporated into mechanistic models like Species Distribution Models (SDMs) to predict species geographic occurrence and the impact of future extreme scenarios. Such holistic and integrative physiological approaches will enhance our understanding of species and population resilience, and will facilitate the identification of vulnerable populations, ultimately improving management strategies. By prioritizing these research efforts, we will better anticipate the impacts of environmental changes on wildlife health, and thus improve biodiversity conservation strategies. Lay SummaryUnderstanding the effects of extreme environmental conditions on the ecology and physiology of wildlife is key to improve conservation strategies. Here, we discuss different representative study systems that examine the ecophysiology of animals coping with extreme environments. We identify research questions that should be incorporated by future studies in this field.</div
P19-30 Biotransformation of the colour developer Pergafast 201 in human in vitro models
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Response of DTT and FOX-based on-line systems for oxidative potential monitoring
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Perinatal air pollution exposure and autism spectrum disorder severity: The intertwined roles of green space, grey space and healthcare accessibility – A cohort study
No full textInternational audienceIntroduction: Autism spectrum disorder (ASD) is influenced by environmental, genetic, and socio-economic factors. While air pollution exposure during development has been linked to ASD outcomes, the roles of green spaces, grey spaces, and healthcare accessibility in this relationship remain understudied. This research examines how these factors during the first 1000 days (from conception to the first two years of life), moderate the association between air pollution and ASD severity in children from the ELENA cohort ("Etude Longitudinale chez l'Enfant avec Autisme").Methods: Data from 237 children with ASD were analyzed. Perinatal exposure to particulate matter (PM 10 and PM 2.5 ) was estimated using a validated model, with green spaces quantified using the normalized difference vegetation index (NDVI) and grey spaces through impervious surface coverage. Healthcare accessibility was measured as the distance to autism resource centers (CRA) from residential addresses. ASD severity was assessed using the total score of the Social Responsiveness Scale. Linear regression models within structural equation modeling estimated the effects of air pollution, green spaces, grey spaces, and healthcare accessibility on ASD severity.Results: Higher PM exposures were paradoxically associated with lower ASD severity. However, grey spaces significantly moderated this association, with greater impervious surface coverage attenuating the negative association. Healthcare accessibility was crucial: when considering center proximity, pollution was no longer associated with ASD severity.Conclusions: These findings highlight the critical role of healthcare accessibility and environmental factors in shaping the relationship between air pollution and ASD severity. Integrating geographic and environmental contexts is crucial when evaluating the environmental determinants of ASD outcome
Effects of co-exposure to benzo-a-pyrene and cerium dioxide nanoparticles on human lung and placental barriers
No full textInternational audienceCerium dioxide nanoparticles (CeO2 NPs) are emerging pollutants widely used for their catalytic properties in diesel fuel and cigarettes. Human exposure to CeO2 NPs rarely occurs in isolation. Benzo-a-pyrene (BaP), a polycyclic aromatic hydrocarbon co-emitted from diesel engines, tends to adsorb onto CeO2 NPs in contaminated environments. To better understand their combined effects on both the lung and placental tissues which arecritical-barriers for the fetus, we coated CeO2 NPs with BaP at two different ratios, mimicking environmental exposure. We characterized the physicochemical properties of BaP-coated NPs in bronchial and placental culture media, assessed coating stability and BaP desorption. We evaluated the biological impact of BaP-coated CeO2 NPs son primary normal human bronchial epithelial cells and purified villous cytotrophoblasts from term human placentas. We compared the response of BaP-coated NPs with that observed under parallel co-exposure, and to individual exposures to BaP and CeO2 NPs. Bronchial cells exhibited toxicity at lower doses under co-exposure by parallel addition compared to BaP-coated NPs. Cytochrome P450 (CYP1A1) induction varied between tissue barriers, exhibiting a BaP dose-dependent response in both tissue models but coating-independent response in trophoblasts, whereas bronchial cells showed a stronger response to BaP adsorbed on CeO₂ NPs. These findings highlight how BaP, when stably associated with CeO2 NPs, exerts modulated effects depending on the tissue,potentially altering its metabolic kinetics and thus its biopersistence. This study underscores the importance ofconsidering particle-bound pollutants when evaluating the health impact of airborne particulate matter, as thismore accurately reflects environmental exposur
Implantation of Aspergillus Section Flavi in French Maize and Consequences on Aflatoxin Contamination of Maize at Harvest: Three-Year Survey
No full textInternational audienceThe worldwide distribution of aflatoxin B1, a carcinogenic mycotoxin, is changing due to climate change. This frequent contaminant of crops in tropical and subtropical regions is an emerging threat in Europe. Its first appearance in French maize was reported in 2015, a year with exceptional climatic conditions. But, from this year, such conditions (drought during spring and hot summers) occurred regularly, raising the question of a possible durable implantation of aflatoxigenic fungal species in French maize fields. To answer this question, 554 maize samples were collected during three consecutive years (2018–2020) throughout the French territory. They were subjected to mycological analysis and strains belonging to the Flavi section of the Aspergillus genus were identified, and their toxigenic potential was determined. This survey demonstrates that Aspergillus section Flavi are now frequent contaminants of maize since they were observed in more than 50% of samples in 2018 and 2019. This prevalence sharply increased in 2020 to reach 80% contamination. In parallel, the frequency of contamination with aflatoxins also increased. While it was very limited during the first two years of the study, despite favorable climatic conditions, contamination with aflatoxins was present in 16% of samples analyzed in 2020, exceeding E.U. regulation by 5%. Even if Aspergillus flavus is the dominant species, representing more than 90% of isolated strains, Aspergillus parasiticus seems to play a major role in grain contamination, as demonstrated by the presence of AFG in 50% of contaminated samples. These findings highlight the need to rethink the monitoring and management of aflatoxin risk in France for the future
Fast In-Phantom Absorbed Power Density Evaluation at mmWaves Based on Infrared Measurements
No full textInternational audienceThis article introduces a novel method for fast measurement of the absorbed power density (APD) induced by an electromagnetic field (EMF) emmitting device operating near the human body at frequencies above 6 GHz, taking into account antenna/body interaction. The method employs an infrared (IR) thermography to remotely monitor the heat induced in a reflectivity-based skin equivalent phantom designed to reproduce the EMF scattering properties of human skin and the APD inside the human body. Such a phantom, implemented in the form of a thin planar solid dielectric structure, perturbs the device under test in a similar way as it would be perturbed by the presence of the human body, allowing the absorbed microwave energy to be effectively converted into an IR signal. The heat dynamics and the spatial temperature distribution on the phantom surface are measured by an IR camera and then converted to APD by postprocessing. To enhance the sensitivity of the method and to minimize the effect of heat conduction, spectral filtering is used. The proposed method is validated at 60 GHz using reference antennas (i.e. a cavity-fed dipole array and a pyramidal horn loaded with a slot array). The measured APD is compared with the reference APD simulated in human skin. The high accuracy and significant measurement time reduction, compared to conventional RF-based APD evaluation techniques, demonstrate a promising potential of the proposed IR-based method for fast EMF dosimetry and user exposure compliance testing of millimeter-wave (mmWave) 5 G and 6 G wireless devices
Occupational exposure to ultrafine particles and lung cancer in a population exposed to asbestos
No full textInternational audienceBackground: Ultrafine particles are present in ever greater quantities in the workplace and only one epidemiological study to date has found an association with the occurrence of lung cancer.Objective: To investigate the effect of occupational exposure to ultrafine particles on the risk of lung cancer.Methods: The ARDCO is a surveillance program involving retiree workers who had been exposed to asbestos during their working life. Exposure to ultrafine particles over the complete lifetime occupational history was assessed using the French job exposure matrix MATPUF. Cox proportional hazard models were used to estimate hazard ratios (HRs) and 95% confidence intervals (95% CI).Results: There was no association between exposure to ultrafine particles and lung cancer after adjustment for smoking and exposure to asbestos and crystalline silica.Conclusion: The findings do not indicate increased risks of lung cancer for UFP after adjustment for level of exposure to asbestos, crystalline silica, and smoking status.Clinical trial number: Not applicable
Wavelength-dependency of the impact of light on proliferation and DNA damage of corneal cells in vitro
No full textInternational audienceThe wavelength-dependent impact of light has been mainly studied focusing on retina. In particular, an opposite effect of the two ends of the visible spectrum was observed, with blue wavelengths being harmful and red wavelengths being protective. However, few studies on the cornea indicate that the increasing exposition to artificial light due to digital devices is linked to an increase in computer vision syndrome affecting the cornea. In this study, we aim at deciphering the impact of blue and red LED light on a primary culture of corneal endothelial cells, by looking at cell death and proliferation, and at DNA replication and DNA breaks. Our results show that exposure to blue light at 5.35 J/cm²(455 nm) induces the inhibition of DNA replication and cell proliferation, and the formation of DNA breaks, highlighted by the formation of γH2AX foci and DNA fragmentation. Addition of red light at 0.3 J/cm² (630 nm) to blue light mitigates the formation of DNA damage and delays the kinetics of formation and repair of the damage. Interestingly, exposure of the corneal cells to red light alone induces the formation of γH2AX foci that do not correspond to DNA breaks, but to DNA replication forks in proliferative cells. Our results highlight the wavelength-dependent effect of light on the cornea, and point out that the formation of γH2AX foci is not always representative of DNA breaks. This emphasizes the importance of light spectrum in eye health, an important issue in today's changing light environment.</div