Persistent organic pollutants (POPs) and adipose tissue hypoxia have been shown to independently affect adipocyte functions. The goals of this study were to (1) determine the effect of PCB-77, PCB-153, and DDE on the differentiation of human preadipocytes, and (2) investigate the cross-talk between PCB-77 and hypoxia in differentiated human adipocytes. First, human preadipocytes were exposed to PCB-77, PCB-153, or DDE during the entire 14-day differentiation period. We found no effect of low POP levels on lipid accumulation. Second, differentiated human adipocytes were exposed to a combination of PCB-77 and hypoxia. We demonstrated gene-specific cross-talk between PCB-77 and hypoxia, showing an additive effect of PCB-77 on VEGF, MCP-1, and adiponectin, as well as an inhibition of PCB-77-induced expression of CYP1A1 by hypoxia. This work has expanded our understanding of the role of POPs and hypoxia in differentiated human adipocytes.

Dans ce travail, nous avons modifié deux carbones activés (grain AC et tissu T0) par divers traitements chimique (H2O2, NaOCl et un traitement thermique sous azote) et par des traitements ultrasonores à 20 et 500 kHz en présence de différents solvants (eau ultrapure, peroxyde d'hydrogène et acide formique). Ces carbones (bruts et modifiés) ont été caractérisés du point de vue de leur chimie de surface et de leur texture. Nous avons étudié l'adsorption d'ibuprofène (IBP) aux différents pH et températures. Le processus d'adsorption de l'IBP sur (AC ou T0) est avéré endothermique à pH 3. L'oxydation par NaOCl crée des groupes phénoliques qui défavorisent l'adsorption d'IBP tandis que l'oxydation par H2O2 augmente la teneur en groupe carbonyles et carboxyles responsable d'une contribution à l'adsorption de l'IBP. Le traitement ultrasonore de AC a augmenté son adsorption d'IBP par rapport au charbon brut. La cinétique d'adsorption de deux liquides ioniques synthétisés (LI1 : bromure de 4-tertiobutyl-1-propylpyridinium et LI2 : bromure de 4-tertiobutyl-1(2-carboxy-ethyl)pyridinium ) sur T0 est beaucoup plus rapide que la cinétique d'adsorption de l'IBP à pH 7,5. La compétition d'adsorption sur T0 entre les trois molécules (IBP et les deux liquides ioniques) a montré que l'IBP s'adsorbe en plus grande quantité sur le T0 que le LI1 et le LI2. / In this work, two activated carbons (granular AC and fabric T0) were modified either by chemical treatment (H2O2, NaOCl and thermal treatment under N2) or by ultrasonic irradiation at 20 kHz or 500 kHz in different solvents (UHQ water, H2O2 and HCOOH). The raw and modified materials were characterized by different methods. We studied the ibuprofen (IBP) adsorption at different pH and temperatures. The adsorption of IBP by (AC or T0) was an endothermic process at pH 3. Oxidation with NaOCl creates phenol groups that led to a decrease of the adsorption uptake while oxidation by H2O2 increases the carbonyl group content and carboxyl that induce an increase in the adsorption of IBP. The ultrasonic treatment of AC increases the adsorption capacity of ibuprofen in comparison with the raw AC. The adsorption of the two ionic liquids (LI1 : the 4(tert-butyl)-1propylpyridinium bromide and LI2 : 4(tert-butyl)-1(2-carboxy-ethyl)pyridinium bromide ) onto T0 was found much faster than the adsorption kinetic of IBP at pH 7.5. The competitive adsorption of mixture of IBP and the two ionic liquids showed that IBP is the most adsorbed by T0.

Philosophiae Doctor - PhD / The thesis presents a simple, sensitive, low cost and a novel graphenated polyaniline doped tungsten trioxide nanocomposite, as an electrochemical sensor for the detection and quantitative and determination of PAHs, which are ubiquitous, toxic, as well as dangerous organic pollutant compounds in the environment. The selected PAHs (anthracene, phenanthrene and pyrene) in wastewater were given priority as a result of their threat to human nature and that of the environment. In order for a healthy, non-polluted and well sustainable environment, there is need for an instrument that is capable of detecting and quantifying these organic pollutants onsite and also for constant monitoring. The nanocomposites were developed by chemical and electrochemical methods of preparations, exploiting the intrinsic properties of polyaniline, graphene and tungsten trioxide semiconducting materials. Chemically, graphene-polyaniline (GR-PANI) nanocomposite was synthesised by in situ polymerisation method, then casted on a surface of glassy carbon electrode to form GR-PANI modified electrode. The properties of the prepared electrode were investigated through morphological and spectroscopic techniques, which confirmed the formation of the composite. The electroactivity of the prepared modified electrode revealed great improvement in cyclic and square wave voltammetric response on anthracene. A dynamic range of 2.0 × 10-5 to 1.0 × 10-3 M and detection limit of 4.39 x 10-7 M was established.

O acúmulo de poluentes orgânicos persistentes é um dos principais problemas de contaminação do meio ambiente em todo o mundo. As atividades industriais e os avanços tecnológicos na maioria dos setores de produção contribuem com a crescente liberação de compostos poluentes, altamente tóxicos, biocumulativos e resistentes à degradação física, química, fotolítica e biológica. Esses poluentes são o resultado do uso indevido de pesticidas de um modo geral, da subprodução não planejada de sintéticos tóxicos como dioxinas policloradas e de uma lista enorme de atividades que promovem a combustão incompleta da matéria orgânica e despejam no ambiente uma vasta quantidade de hidrocarbonetos aromáticos persistentes. A biorremediação é uma estratégia biotecnológica que vem lançar luz sobre as técnicas de revitalização de sítios contaminados. É baseada na utilização de microorganismos, ou suas enzimas, para reduzir ou eliminar perigos ambientais contaminantes em substâncias inertes, CO2 e água. As oxigenases são uma classe de enzimas amplamente estudadas por suas propriedades catalíticas únicas, sendo a clorocatecol 1,2- dioxigenase de Pseudomonas putida um interessante alvo biotecnológico para a biorremediação devido a sua ampla especificidade a substratos aromáticos, aromáticos halogenados e dialogenados altamente poluentes, biocumulativos e carcinogênicos. Nesse trabalho, o protocolo de expressão heteróloga em E. coli foi implementado em nosso laboratório e a purificação realizada em coluna de afinidade através do uso de resina de quitina. Os cristais de cor marrom avermelhado da enzima clorocatecol 1,2-dioxigenase Pseudomonas putida foram obtidos na presença de polietilenogligol e acetato de magnésio durante o período de 10 dias, utilizando-se a técnica de difusão de vapor em gota sentada. A estrutura cristalográfica da enzima Pp 1,2-CCD foi determinada através da utilização da técnica MR-SAD, utilizando átomos de ferro, cofator da proteína, como agentes espalhadores e as coordenadas da enzima 3-clorocatecol 1,2-dioxigenase de Rhodococcus opacus como modelo de busca. O modelo final, contendo 3 moléculas na unidade assimétrica foi refinado a 3.4 Å de resolução. A enzima se enovela na forma dimérica (Fe3+)2, e apresenta de um modo geral, dois domínios catalíticos compostos de fitas-beta e uma região de loops e um domínio de ligação composto por hélices formando um túnel hidrofóbico. Como a primeira clorocatecol de bactérias gram-negativa a ser descrita para essa classe de enzimas, será possível investigar as diferenças conformacionais que levam aos mecanismos de catálise, amplo a diversos substratos, e avaliar características de seu funcionamento e ativação, como uma importante ferramenta para validação do papel desta proteína dentro do processo de biorremediação. / Accumulation of persistent organic pollutants is one of the most important environmental problems worldwide. Industrial activities and technological advances contribute to the spread of pollutants, highly toxic, bioaccumulative, and resistant to physical, chemical, photolytic and biological degradation. The persistent organic pollutants are consequence of the inappropriate use of pesticides, the production of toxic synthetic compounds such as polychlorinated biphenyls and a large list of activities promote incomplete combustion of which organic matter and release a large amount of persistent aromatic hydrocarbons to the environment. Bioremediation is a biotechnogical strategy that has shed light on revitalization techniques of contaminated sites. It is based on the application of microorganisms, or their enzymes, to eliminate or reduce environmental contaminants into inert substances, CO2 and water. The oxygenases are a class of largely studied enzymes due to their catalytic properties, being chlorocatechol 1,2-dioxygenase from Pseudomonas putida an interesting biotechnological target for bioremediation due to its specificity to a broad spectrum of highly polluted aromatic substrates. In the present work, heterologous expression protocol has been implemented in our laboratory and purification was performed by using affinity column in chitin resin. Brown-reddish crystals of chlorocatechol 1,2-dioxygenase from Pseudomonas putida were obtained in presence of polyethylene glycol (PEG) and magnesium acetate after 10 days, by utilizing vapor diffusion techniques in sitting drops. The crystallographic structure of Pp 1,2-CCD has been solved by MR-SAD technique, using iron atoms, the enzyme cofactor, as scattering centers and the coordinates of 3- chlorocatechol 1,2-dioxygenase of Rhodococcus opacus as the search model. The final model, containing three molecules in the asymmetric unit, has been refined up to 3.4 Å resolution. The enzyme folds in the dimeric form (Fe3+)2, and shows two catalytic domains composed of -strands and a loop region, and a helical domain that pack together forming a hydrophobic channel. As being the first member of the chlorocatechol dioxygenase family of enzymes from a gram-negative bacteria to be solved, it will be possible to explore the crystallographic structure of chlorocatechol 1,2- dioxygenase from Pseudomonas putida in order to investigate the conformational differences that explain its mechanism of action, on a broad spectrum of substrates, and evaluate the functional features, as an important tool to validate the role of this enzyme in the bioremediation process.

A poluição atmosférica já é considerada um caso de saúde pública nos grandes centros urbanos. Freqüentemente as emissões veiculares são as principais causas dessa poluição, principalmente as provenientes dos motores diesel, os quais, além da produção de material particulado (MP), em cuja superfície são adsorvidas substâncias carcinogênicas e mutagênicas, produzem poluentes como os hidrocarbonetos policíclicos aromáticos (HPAs). Contudo não existe uma avaliação direta dos riscos dessas emissões nos seres vivos. Plantas bioindicadoras podem dar idéia desses riscos. Este trabalho teve como objetivo avaliar o potencial de risco mutagênico da exaustão proveniente de um motor diesel, utilizando o bioensaio Trad-SH (clone KU-20) como bioindicador da poluição do ar. Nos experimentos, a exaustão do motor diesel aspirado de 2.0 L de deslocamento volumétrico foi diluído com ar atmosférico de modo a atingir concentrações de uma atmosfera pesadamente poluída (aproximadamente 50, 100 e 150 ppm de CO). Obtidos estes níveis de diluição, as inflorescências foram expostas a esta mistura de poluentes por duas horas (doses agudas). A concentração de CO foi monitorada continuamente por meio de um analisador de gases Horiba Enda utilizando o princípio de absorção seletiva no infravermelho. Para se avaliar o efeito mutagênico foi feita uma comparação entre as inflorescências não expostas aos poluentes (grupo 1) e as inflorescências expostas (grupos 2, 3 e 4) com aproximadamente 50, 100 e 150 ppm de CO respectivamente. Os dados obtidos foram analisados estatisticamente observando-se que, a freqüência média das mutações no grupo 1 (controle), foi significativamente mais baixa do que aquela dos grupos 3 e 4, porém foi similar à do grupo 2. Por sua vez, não houve diferenças significativas nas freqüências de mutações entre os grupos 3 e 4. Os resultados indicam que a exaustão do motor a diesel teve um papel significativo no desenvolvimento de mutações, mas somente quando diluída para concentrações de CO acima de 100 ppm. / Air pollution caused by vehicle emission has been considered as a major public health concern in the urban centers. Emission from diesel engine powered vehicles, in particular, are highly toxic, since carcinogenic and mutagenic compounds can adsorb on the expelled particles leading to the formation of the so-called polycyclic aromatic hydrocarbons (PAH\'s). A detailed investigation on the risks of those compounds on the living beings using the methodology applied in the work has not been carried out so far. This work is aimed at evaluating the mutagenic potential of the emission from a diesel engine using the Tradescantia stamen hair assay (TSH), by monitoring the stamen hair mutation in the clone KU-20. Experimentally, the inflorescence of the KU-20 clones was kept for 2 h under a simulated urban heavily polluted atmosphere, obtained by mixing the emission from a diesel engine and atmospheric air. The CO concentration in the atmosphere was monitored using a Horiba-Enda gas analyzer. The mutagenic effects of the atmosphere were analyzed by comparing a group of non-exposed control inflorescence (group 1) to inflorescences kept under polluted atmospheres containing 50, 100 and 150 ppm of CO, assigned to as groups 2, 3 and 4. The experimental data were analyzed using statistical methods. The frequency of mutations observed in the inflorescences from group 2 was slightly higher than that observed in the group 1. In the groups 3 and 4, however, the frequency of mutations was significantly higher than that exhibited by the control group. The latter suggests that the emission from a diesel engine plays an important role in the development of plants mutation, specially for atmospheres containing more than 100 ppm of CO.

No description available.

L’être humain est exposé quotidiennement et simultanément à des dizaines de polluants environnementaux, pourtant il n’existe encore que peu ou pas d’études sur les effets de ces mélanges. Des études épidémiologiques et transcriptomiques montrent que les polluants peuvent perturber le métabolisme glucidique et lipidique. Le lien entre métabolisme et cancer a été démontré depuis plusieurs décennies, en effet, une dérégulation du métabolisme oxydatif, appelée effet Warburg, et commune à presque toutes les cellules tumorales se caractérise par une déviation du métabolisme oxydatif mitochondrial vers une glycolyse anaérobie entrainant une augmentation de la production de lactate. Pour ce travail les effets d’un mélange de deux polluants organiques persistants ayant des voies de signalisation différentes sont étudiés. Le mélange associe la TCDD, une substance cancérigène, à un pesticide l’α-endosulfan, afin d’évaluer les effets combinés de ces deux polluants sur le métabolisme énergétique de cellules cancéreuses coliques humaines Caco2. Le traitement des cellules pendant 48 heures par la TCDD (25 nM) et l’α-endosulfan (10µM) conduit à une diminution de l’oxydation du glucose, corrélée à une augmentation de la production de lactate, alors que chaque polluant seul exerce un effet peu significatif. Le mélange diminue l’activité globale de la mitochondrie caractérisée par une diminution de la respiration cellulaire, et de la production d’ATP sans toutefois modifier l’intégrité mitochondriale. L’étude des mécanismes impliqués dans ces effets indique l’implication de l’AMPK et du complexe PDH, deux enzymes clés régulant de façon très importante la glycolyse cellulaire ; en effet l’inhibition de l’AMPK abolit les effets des polluants. Des modifications du calcium intracellulaire qui régule entre autre l’activité de ces deux enzymes sont observées et l’inhibition du calcium abolit également les effets des polluants. Ces travaux montrent que le mélange induit une aggravation de la dérégulation du phénotype métabolique des cellules Caco2 à l’état prolifératif. Cela pourrait signifier une synergie de l’activité de ces polluants qui pourrait accentuer ce phénotype dans un contexte tumorale via un mécanisme impliquant le calcium. / During tumorigenesis most of cancer cells exhibit an altered metabolism that is characterized by an elevated uptake of glucose and an increased glycolytic rate; this phenomenon is known as the Warburg effect. Compelling recent evidences suggest that alteration of cellular metabolism is critical during cancer development and constitutes a major feature of aggressive tumour. Considering the recent observations on the impact of persistent organic pollutants (POPs) on cell metabolism, we hypothesize that POPs could exert their carcinogenic effects by promoting metabolic alterations that could converge to a metabolic shift supporting a tumoral phenotype. Proliferating colon cancer cells (Caco2) were treated with TCDD (25 nM) or/and α-endosulfan (10 µM), two environmental pollutants mainly produced by human activities and designated by the International Agency for Research on Cancer as probably or well-established carcinogenic to humans. A significant decrease of glucose and glutamine oxidation (60%) was observed after a treatment for 48 hours with the two pollutants while each pollutant alone had no significant effect. These observations are correlated with an increased lactate production by two fold. These effects are maintained in the presence of antioxidative NAC (10 mM), suggesting that they are independent of the oxidative status of the cell. We also observed a decreased incorporation of glucose in total lipids (50%). The ATP production and the cell respiration level were significantly decreased by the mixture by about 50% and 80%, respectively. In the same conditions, the glycogen production and the NADPH/NADPH,H+ ratio were unchanged. Taken together, these results suggest that POPs could worsen the metabolic phenotype of cancer cells. The molecular mechanisms underlying the POPs-induced metabolic reprograming are under investigation and should provide a better understanding of the signalling pathways involved in POPs action on the regulation of the energetic metabolism balance and their consequence on cancer.

Les composés organiques semi-volatils (COSV) font l’objet d’une attention croissante depuis une dizaine d’années. Utilisés dans de nombreux produits et matériaux du quotidien, ils sont émis dans les bâtiments par dispersion lors de l’usage, par évaporation ou abrasion. Du fait de leurs caractéristiques physico-chimiques, ces composés se répartissent à la fois dans l’air, en phases gazeuse et particulaire, et dans les poussières déposées au sol, sur le mobilier et les objets. Compte tenu du temps passé par la population dans les bâtiments, en particulier par les populations sensibles comme les enfants, les femmes enceintes et les personnes âgées, l’exposition à ces substances mérite d’être documentée, tenant compte des voies d’exposition en jeu : inhalation, ingestion et contact cutané. La thèse a porté sur les COSV présents en phase particulaire dans les logements. L’objectif de la thèse visait à exploiter les mesures de 66 COSV dans les particules en suspension de diamètre inférieur à 10 µm (PM10) et de 48 COSV dans les poussières au sol de taille inférieure à 100 µm considérées comme étant celles adhérant à la peau. Ces mesures ont été réalisées dans le cadre de deux campagnes nationales : la campagne « Logements » de l’Observatoire de la qualité de l’air intérieur conduite en 2003-2005 et l’enquête Plomb-Habitat dont les prélèvements ont eu lieu en 2008-2009. Une hiérarchisation des molécules jugées prioritaires au regard de leur impact sanitaire potentiel avait permis au préalable d’établir la liste des COSV à mesurer. L’exploitation de ces données de contamination a notamment porté sur l’identification d’éventuelles spécificités françaises au regard des molécules en présence et/ou des concentrations mesurées. Elle a permis de mettre en lumière un ensemble de facteurs déterminants de l’exposition (influence de la taille des particules, du type de poussières collectées, de leur bioaccessibilité), qui ne sont pas toujours considérés et qui limitent par ailleurs la comparabilité des résultats. Les concentrations mesurées ont aussi permis d’évaluer rétrospectivement la hiérarchisation sanitaire et d’en confirmer la pertinence. Les concentrations des COSV quantifiés à la fois dans l’air et au sol ont été mises en perspective afin d’examiner dans quelle mesure les particules en suspension et les poussières déposées sont similaires en termes de concentrations et de mélanges de COSV en présence. Enfin, l‘estimation des doses d’exposition aux COSV à partir d’équations simples, de variables humaines d’exposition et des données de contamination a permis une première évaluation des contributions respectives de l’inhalation et de l’ingestion aux expositions domestiques des enfants et adultes à ces composés en phase particulaire. / Semi-volatile organic compounds (SVOCs) refer to a broad spectrum of molecules from different chemical families that have numerous properties. They can be used as pesticides, plasticizers, flame retardants, surfactants, lubricants, etc. Consequently, they are introduced in numerous applications in buildings or used daily by the entire population. Once emitted through evaporation or abrasion in the indoor environment or introduced from the outdoors, their chemical or biological degradation is limited, and they persist indoors. This persistence also explains why some SVOCs that were banned a few years ago are still detected in the air and dust inside buildings. In indoor environments, SVOCs are divided between the gas phase, airborne particles, and dust settled on floors and surfaces. SVOCs are of concern due to their established or suspected health effects and their widespread exposure through different environmental media and pathways. The objective of the thesis was to study the concentrations of 66 SVOCs on airborne particles (PM10) and 48 SVOCs in settled dust in two samples of dwellings randomly selected across France. PM10 were sampled during the nationwide housing survey carried out by the French Observatory of indoor air quality in 2003-2005. The dust samples were collected from vacuum cleaner bags during a nationwide survey carried out in French dwellings where at least one child aged 6 months to 6 years lived (2008-2009). The SVOCs to be analyzed had prior been selected using a ranking method based on their toxicity and indoor concentrations. The data analysis focused in particular on the identification of French specificities in terms of detected molecules and measured concentrations. It highlighted some determinants of exposure, e.g., influence of particle size, type of dust collected, dust bioaccessibility, which are not always considered and limit the comparability of results. The measured concentrations were also used to assess the health ranking implemented prior to this work and to confirm its relevance. The concentrations measured both in the air and in settled dust were compared to study the similarities in terms of concentrations and SVOC mixtures. Finally, the exposure doses to SVOCs were calculated for both a child and an adult to assess the respective contributions of inhalation and ingestion to these compounds in particulate phase in dwellings.

Persistent organic pollutants (POPs) and adipose tissue hypoxia have been shown to independently affect adipocyte functions. The goals of this study were to (1) determine the effect of PCB-77, PCB-153, and DDE on the differentiation of human preadipocytes, and (2) investigate the cross-talk between PCB-77 and hypoxia in differentiated human adipocytes. First, human preadipocytes were exposed to PCB-77, PCB-153, or DDE during the entire 14-day differentiation period. We found no effect of low POP levels on lipid accumulation. Second, differentiated human adipocytes were exposed to a combination of PCB-77 and hypoxia. We demonstrated gene-specific cross-talk between PCB-77 and hypoxia, showing an additive effect of PCB-77 on VEGF, MCP-1, and adiponectin, as well as an inhibition of PCB-77-induced expression of CYP1A1 by hypoxia. This work has expanded our understanding of the role of POPs and hypoxia in differentiated human adipocytes.

Since the late 18th century, chemicals have been industrially produced, and used by consumers. Today, the number of registered chemicals are over 150 000 in North America and Europe alone, and the number is predicted to increase. Industrial or anthropogenic chemicals can, directly or indirectly, be released into the ecosystem during their lifetime, where they can cause harm to human health and the environment. Depending on their properties, chemicals can travel far away from its source, causing global contamination. Through this, the Arctic region becomes a sink for many different types of contaminants. Because of the danger certain chemicals pose, techniques to detect and identify them in environmental samples have evolved during recent years. In these cases, non-targeted screening methods are commonly used to characterise contaminants in samples.In this study, surface sediment samples were collected on three locations in the Hudson Bay (Canada). The samples were analysed using two different instruments: a comprehensive two-dimensional gas chromatograph coupled to a high resolution time-of-flight mass spectrometer (GC×GC-HR-ToF-MS) and a gas chromatograph coupled with a Orbitrap mass spectrometer (GC-Orbitrap-MS). After data acquisition and processing, certain components were identified in both datasets, and their semi-quantitative concentrations were calculated.Overall, 32 compounds were detected and identified in the Orbitrap dataset, and 17 of these were also detected in the GC×GC dataset. The concentration was determined semi-quantitively for the identified compounds and ranged from 0.005–333 ng/g dry weight (d.w.) for the Orbitrap dataset, and 0.013–278 ng/g d.w. for the GC×GC dataset, which was below, or in the lower half, of concentration ranges from previous studies. Overall, the data processing for Orbitrap data seems to be more advanced and evolved than for GC×GC data, causing differences between the results from the two instruments.