Preeclampsia (PE), characterized by hypertension and proteinuria after 20 weeks of gestation, affects 5-8% of pregnancies worldwide. Although preeclampsia is a significant cause of maternal and perinatal mortality and morbidity, its etiology remains to be elucidated. Racial differences have been observed for preeclampsia, with U.S. Blacks having higher rates and more severe disease, compared to U.S. Whites and Hispanics. One potential source of racial differences in preeclampsia is genetic variation between populations. Genetic susceptibility to preeclampsia is well established, but the specific contributions of maternal vs. fetal genes, and how these vary among racial groups is poorly understood. This dissertation addressed racial differences in the genetics of preeclampsia in Chileans, U.S. Blacks, and U.S. Whites through candidate gene studies and variance components modeling. First, we determined whether three genes, which are relevant to the pathophysiology of preeclampsia, Catechol-O-methyltransferase (COMT), Methylenetetrahydrofolate reductase (MTHFR), and Endoplasmic reticulum aminopeptidase 2 (ERAP2), were associated with the risk for preeclampsia in Chilean and U.S. Black mothers and fetuses. We found that the maternal COMT and an interaction between the fetal COMT and MTHFR were associated with the risk for preeclampsia in Chileans. We also found that the fetal ERAP2 was associated with the risk for preeclampsia in U.S. Blacks. We next used structural equation modeling of a unique Children of Twins (COT), supplemented with full and half-siblings, study design to investigate the fetal genetic, maternal genetic, shared environmental, and unique environmental contributions to preeclampsia in U.S. Whites and Blacks. Through this modeling we uncovered a unique source of racial differences in preeclampsia. We found that U.S. Whites and Blacks showed a similar prevalence of preeclampsia in first births, but across the next three births, the prevalence in Whites declined to a greater degree than in Blacks. In conclusion we have identified specific maternal and fetal genes that contribute to the risk for preeclampsia. Furthermore, we have identified sources of racial differences in preeclampsia, which include differences in associations between COMT, MTHFR, and ERAP2 and the risk for preeclampsia among populations and differences in the prevalence of preeclampsia across subsequent births between U.S. Whites and U.S. Blacks.

La tyrosinase est une métalloenzyme à cuivre de type 3 impliquée dans la biosynthèse de la mélanine. La compréhension et la modulation de cette enzyme ont plusieurs enjeux importants, notamment dans les domaines médical, cosmétique et agroalimentaire.A travers la synthèse et l'évaluation de composés actifs, sur la réaction catalysée par la tyrosinase, des relations structures activités ont pu être mises en lumière sur des tyrosinases provenant d'espèces différentes.L'ensemble des molécules analysées a permis de découvrir des inhibiteurs prometteurs de la tyrosinase mais aussi des substrats alternatifs et des activateurs hyperboliques. Cette grande variété d'activité révèle la présence d'un site allostérique sur la tyrosinase d'Agaricus bisporus.Parallèlement, la synthèse d'un analogue d'un inhibiteur compétitif de la tyrosinase (le HOPNO), marquée à l'azote 15, a été réalisée. Cette molécule sonde servira à déterminer, par RMN paramagnétique, le mode de fixation de ce fragment dans le site actif. / Tyrosinase is a copper metalloenzyme type 3 involved in the biosynthesis of melanin.Understanding and modulation of this enzyme have several important issues, including the medical, cosmetic and food .Through the synthesis and evaluation of active compounds, the reaction catalyzed by tyrosinase, structures relations activities have been highlighted on tyrosinases from different species. All molecules analyzed revealed promising inhibitors of tyrosinase but also alternative substrates and activators hyperbolic. This wide variety of activity indicates the presence of an allosteric site on tyrosinase of Agaricus bisporus. Meanwhile, the synthesis of an analogue of a competitive inhibitor of tyrosinase (the HOPNO), labeled with 15 N, was carried out. This probe molecule used to determine, by paramagnetic NMR, the binding mode of the fragment in the active site.

Hydroxytyrosol, 3,4-dihydroxyphenolethanol, a naturally occurring polyphenol most common in olive tree (Olea europaea), is one of the most effective member of the polyphenols family, because of its remarkable antioxidant activity, its ability to inhibit oxidation of low density lipids (LDL), and its protection against DNA oxidative damage. Hydroxytyrosol, which is widely used in cosmetics and food supplements industries, can be purchased as an olive oil extract that contains low concentration of hydroxytyrosol besides other polyphenols. The price and low natural abundance of hydroxytyrosol make alternative synthetic sources very attractive. In this research, a novel method for the synthesis of pure hydroxytyrosol from a commercially inexpensive precursor catechol was developed; this can satisfy the increasing market demand and provide a more economical alternative source for this valuable polyphenol.

Copper is one of the essential metal ions for aerobic organisms. Two well known functions of copper in the biological systems are electron transfer and molecular oxygen interaction. Thus, this metal can be found in haemocyanin, an oxygen carrier protein, and superoxide dismutase, an enzyme that involves in electron transfer. In addition, having a positive redox potential allows copper to be involved in redox chemistry. It is the redox properties of copper that are responsible for many important biochemical processes. Although the copper-containing oxidases have been well studied over the years, certain mechanistic details such as reaction intermediates remain to be elucidated. Several research groups have been trying to study this by trying to mimic the native systems, synthesizing bulky organic molecules with copper-binding and oxidative capabilities. However, these model systems are only applicable in organic solvents at low temperatures. In this study, three naturally occurring peptides, amyloid-ß, bacitracin, and histatin 5, have been shown to display the oxidative chemistry when complexed with CuII. A combination of spectroscopic (UV-Vis and NMR) and reactivity was used in studying their metal-binding properties as well as in elucidating their catalytic mechanism.

The objective of this work is the synthesis of model material for manganese dioxygenase which is an enzyme that oxidizes catechol-like substrates with dioxygen. Our strategy comprises three main steps that form the different chapters of this thesis: - Synthesis and characterization of manganese(II) complexes with tridentate ligands. - Optimization of a microwave-assisted synthesis of a mesoporous silica. - Functionalization of these materials and complex grafting, as well as preliminary catalytic tests. The ligands used are tertiary amines containing an alkyne arm and two coordinating arms with functions such as pyridine, imidazole or carboxylate. The complexes were crystallized and/or characterized by IR, EPR, SQUID and cyclic voltamperometry. Microwave synthesis, based on the conditions of classical hydrothermal synthesis, allowed us to reduce the synthesis time from one day to two hours. The quality of these new materials was verified by IR, TGA, BET and powder XRD. These materials are then bi-functionalized using a molecular stencil patterning mehod with a an azide function for complex grafting via click chemistry and a function pyridine or trimethylsilyl to control the coordinating ability of the metal environment. These complexes and materials are active in catechol oxidation with O2.

The catechol-O-methyltransferase (COMT) gene is the predominant means of dopamine deactivation within the prefrontal cortex (PFC), a brain locus implicated in Attention deficit/hyperactivity disorder (ADHD). Dopamine dysregulation is a significant contributor to the pathophysiology of ADHD and Methylphenidate (MPH), an effective treatment for ADHD, and acts at least in part, through modulation of dopamine levels in the PFC. Thus, we tested the hypothesis that the Catechol-O-Methyltransferase (COMT) Val108/158 Met polymorphism modulates behavioral dimensions relevant for ADHD and/or response of these behavioral dimensions to MPH and/or neuropsychological functions considered relevant for ADHD. No genotype or genotype by treatment interaction effects were observed for behavioral response to MPH. No genotype effects were observed using the family-based approach. Marginal genotype effects were observed between the Met/Met genotype and some but not all aspects of executive functioning. Overall, these results do not support the implication of the COMT Val108/158 Met polymorphism in ADHD, ADHD relevant behaviours or response to methylphenidate, but weakly implicate COMT gene in some aspects of executive functions in children with ADHD. Given that gene effects on behaviours are likely to be very small, a much large sample would be needed in order to establish these results, both negative and positive, with better confidence.

Les travaux présentés dans cette thèse portent sur l'étude de performance de matrices phosphocalciques pour une application de dépollution d'effluents liquides. L'objectif à terme est de valoriser des déchets industriels riches en carbonate de calcium en matériaux pour des applications environnementales. Les matrices phosphocalciques ont été préparées à partir de matières premières pures afin de mieux comprendre les processus d'interactions avec les polluants. Ces matrices ont ensuite été évaluées dans le traitement d'effluents liquides synthétiques contenant du zinc ou du catéchol comme substances modèles. La matrice phosphocalcique sous forme de poudre a démontrée une capacité de rétention de zinc élevée, de l'ordre de 140 mgZn/gCa-HA. Sous forme de gel fraîchement synthétisé, cette matrice a été trouvée près de deux fois plus active dans des conditions expérimentales similaires. L'étude environnementale sur ces matrices récupérées à l'issue de la sorption du zinc, a été envisagée via le test de capacité de neutralisation acido-basique (CNAB). Un traitement thermique à une température inférieure à 600°C est suffisant pour stabiliser le zinc et donc limiter sa disponibilité. A l'inverse de leurs performances dans la fixation des métaux, les matrices phosphocalciques ont montré des réactivités relativement faibles vis à vis du catéchol (15 mgC/gCa-HA). Le pH a été trouvé comme étant un paramètre déterminant pour la fixation du catéchol. La fixation, voire dégradation, du catéchol peut être favorable en présence d'ions calciques et zinciques au sein du milieu réactionnel. La capacité d'interaction peut augmenter selon la combinaison métal-ligand. Les possibilités de fixation des polluants organiques restent encore à approfondir compte tenu de leurs extrêmes diversités. / This work investigates the efficiency of calcium phosphate matrices in the treatment of liquid effluents. It has ambition to valorize solid wastes rich in calcium carbonate for environmental purposes. Calcium phosphate matrices were synthesized from pure raw materials to better understand their interactions with pollutant molecules. These matrices were then evaluated in the treatment of liquid effluents containing zinc or catechol as model compounds. Calcium phosphate matrix in powder form presented a high retention capacity for zinc (140 mgZn/gCA-HA). By using calcium phosphate gels freshly synthesized, the sorption capacity increased nearly twice. The acid-base neutralizing capacity (CNAB) was measured in order to evaluate the environmental impact of the matrices recovered after zinc sorption. A thermal treatment below 600°C allows the stabilization of zinc and thus limiting its availability. In contrast to their performances in metal retention, calcium phosphate matrices showed low reactivity for the removal of catechol (15 mgC/gCA-HA). The pH influenced strongly the sorption process. The presence of calcium or zinc ions in the reaction medium may be favourable for the retention and/or degradation of catechol. The affinity may increase according to the metal-ligand combination. It is also interesting to investigate the performance of calcium phosphate matrices for the treatment of other organicpollutants taking into account their large diversity.

Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2015-10-23T12:13:09Z No. of bitstreams: 2 Dissertação - Eli José Miranda Ribeiro Júnior - 2015.pdf: 709119 bytes, checksum: baa5cef4451e6bd53886e3cc249f19df (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2015-10-23T12:15:43Z (GMT) No. of bitstreams: 2 Dissertação - Eli José Miranda Ribeiro Júnior - 2015.pdf: 709119 bytes, checksum: baa5cef4451e6bd53886e3cc249f19df (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2015-10-23T12:15:43Z (GMT). No. of bitstreams: 2 Dissertação - Eli José Miranda Ribeiro Júnior - 2015.pdf: 709119 bytes, checksum: baa5cef4451e6bd53886e3cc249f19df (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2015-01-30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Laccase is a poliphenoloxidase enzyme that catalyzes the oxidation of phenolic compounds in the corresponding quinones. The current obtained in this redox process can be used for quantitative analysis. In this work, a carbon paste biosensor modified gluteraldehyde functionalized silica and an enzymatic extract of the “Pycnoporus sanguineus” fungi as a lacase source is proposed for phenol determination. The effect of carbon paste and electrolyte composition, pH from 3,0 to 8,0, start potential from 0,55 to 0,25mV, scan rate from 5 to 25 mV s-1 and potential pulse amplitude from 10 to 60mV on the differential pulse voltammetric response was investigated. A linear correlation of R² = 0,9946 was obtained for the phenol content (catechol) in the concentration range from 50 to 500nMol L-1, with a detection limit of 30nMol L-1. This biosensor was used for the determination of different kinds of phenolic compounds, presenting a better response for catechol. / A lacase é uma enzima poliphenoloxidase que catalisa a oxidação de compostos fenólicos nas correspondentes quinonas. A corrente obtida neste processo redox pode ser usada para a análise quantitativa da concentração dos fenóis na água. Neste trabalho, é proposto o uso de um biossensor modificado para a determinação de fenol. O biossensor de pasta de carbono com sílica funcionalizada foi modificado com glutaraldeído e um extrato enzimático de fungos “Pycnoporus sanguineus” como uma fonte de lacase. O efeito da pasta de carbono e da composição de electrólito, permite trabalhar com pH compreendido entre 3,0 - 8,0, e um potencial inicial entre 0,55 - 0,25mV. A velocidade de varrimento foi de 5 a 25mV s-1 e amplitude de pulso de 10 a 60mV, estudando-se na resposta voltamétrica de pulso diferencial .Uma correlação linear de R2 = 0,9946 foi obtida para o teor de fenol (catecol) na gama de concentrações de 50 a 500nMol L-1, com um limite de detecção de 30nMol L-1. Este biossensor foi utilizado para a determinação de diferentes tipos de compostos fenólicos, apresentando uma melhor resposta para o catecol.

Polycyclic aromatic hydrocarbons (PAHs) are recalcitrant organic pollutants, which occur widely in the environment. Some of these compounds are carcinogenic and toxic, many studies therefore focus on suitable remediation technologies. It has been shown that composting is an efficient treatment for contaminated solid matrices. Changes in several enzyme activities during co-composting of PAH-contaminated soil were studied in this thesis. The total initial concentration of analyzed PAHs in the soil was 1065 ± 86 µg·g-1 . The chosen activities represented well-known key enzymes involved in the transformation of PAHs or catechol as the central metabolite of PAH microbial degradation. At first, a method for extraction of the selected enzymes from the compost matrix was optimized. This approach was then used for the extraction of the enzymes from compost samples collected at each phase of composting. The activity of manganese peroxidase, laccase, tyrosinase and catechol-2,3-dioxygenase was detected during the cooling and the maturation phase. The only detected activity during the initial mesophilic phase was that of manganese peroxidase. The activities of catechol-1,2- dioxygenase and lignin peroxidase were not detected at all. Despite the fact that PAHs were substantially degraded, no influence of PAHs...

Effluents of industrial wastewaters from oil refineries, paper mills, dyes, ceramic factories, resins, textiles and plastic contain high concentrations of aromatic compounds, which are toxic to organisms. Degradation of these compounds to tolerant limits before releasing them into the environment is an urgent requirement. Candida tropicalis yeast is an important representative of eucaryotic microorganisms that are able to utilize phenol. During the first phase of phenol biodegradation, cytoplasmatic NADPH-dependent phenol hydroxylase of C. tropicatis oxidizes phenol to catechol. Catechol is in the second phase of biodegradative process oxidized to cis,cis-muconic acid by the reaction catalyzed with catechol-1,2-dioxygenase. In this diploma thesis we investigated the effect of the heavy metal ions on NADPH-dependent phenol hydroxylase and catechol-1,2-dioxygenase of C. tropicalis. Phenol hydroxylase was inhibited by Cu2+ and Pb2+ ions. Catechol dioxygenase was inhibited by all substances containing heavy metal ions (Fe2+ , Mn2+ , Cd2+ , Cu2+ and Pb2+ ), which were tested in this work. The most effective inhibition was produced by Pb2+ followed by Mn2+ , Cd2+ Fe2+ and Cu2+ ions. The higher sensitivity of catechol-1,2-dioxygenase to heavy metal ions might follow from the presence of histidine residue...