Made available in DSpace on 2014-12-17T15:41:48Z (GMT). No. of bitstreams: 1 Bruna Vital de Lima_DISSERT.pdf: 1526229 bytes, checksum: 072431027e1aefba9f0023f2f514ae5f (MD5) Previous issue date: 2010-02-02 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The hydrolysis reaction in alkaline conditions of the commercial polymer poly(acrylamide-co-metacrylate of 3,5,5-trimethyl-hexane) called HAPAM, containing 0.75 % of hydrophobic groups, was carried out in 0.1 M NaCl and 0.25M NaOH solutions, varying the temperature and reaction time. The polymers were characterized by 1H and 13C Nuclear Magnetic Resonance (NMR), Elemental Analysis and Size Exclusion Chromatography (SEC). The values of the hydrolysis degree were obtained by 13C NMR. The viscosity of HAPAM and HAPAM-10N-R solutions was evaluated as a function of shear rate, ionic strength and temperature. At high polymer concentration (Cp), the viscosity of HAPAM solutions increased with the ionic strength and decreased with the temperature. The viscosity of HAPAM-10N-R solutions increased significantly in distilled water, due to repulsions between the carboxylate groups. At high Cp, with the increase of ionic strength and temperature, occurred a decrease of viscosity, due to mainly the high hydrolysis degree and the low amount of hydrophobic groups. These results indicated that the studied polymers have properties more suitable for the application in Enhanced Oil Recovery (EOR) in low salinity and moderate temperature reservoirs / A rea??o de hidr?lise em meio alcalino do pol?mero comercial poli(acrilamida-co-metacrilato de 3,5,5 trimetil-hexano) denominado HAPAM, contendo 0,75 % de grupos hidrof?bicos, foi realizada em solu??es de NaCl 0,1 M e NaOH 0,25 M, variando a temperatura e o tempo reacional. Os pol?meros foram caracterizados por Resson?ncia Magn?tica Nuclear (RMN) de 1H e 13C, An?lise Elementar e Cromatografia de Exclus?o por Tamanho (SEC). Os valores do grau de hidr?lise foram obtidos por RMN 13C. A viscosidade das solu??es de HAPAM e HAPAM-10N-R foi avaliada em fun??o da taxa de cisalhamento, for?a i?nica e temperatura. ? alta concentra??o polim?rica (Cp), a viscosidade das solu??es de HAPAM aumentou com a for?a i?nica e diminuiu com o aumento da temperatura. A viscosidade das solu??es de HAPAM-10N-R aumentou significantemente em ?gua destilada, devido ?s repuls?es entre os grupos carboxilato. ? alta Cp, com o aumento da for?a i?nica e da temperatura ocorreu uma diminui??o da viscosidade, devido, principalmente, ao alto grau de hidr?lise e ? baixa quantidade de grupos hidrof?bicos. Estes resultados indicaram que os pol?meros estudados apresentam propriedades mais adequadas para aplica??o na recupera??o avan?ada de petr?leo (EOR) em reservat?rios de baixa salinidade e temperatura moderada

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Changes in land use can take into soil chemical and physical quality degradation. In the hillside areas of the Rio Grande do Sul State (RS) land degradation vulnerability is elevated, due to the combination of a strong undulated to mountainous relief and shallow soils. The general purpose of this study was to evaluate the chemical and physical attributes of soils located in the Sul-riograndense Plateau Border under different land uses. Two representative sites of the Plateau Border, characterized by steep slope areas with prevalence of family farms, were selected (Silveira Martins county (SM) and São João do Polêsine county (SJ)), and also a transition area situated between the Plateau Border and the Medium Plateau (Júlio de Castilhos county (JC)). In SM soil samples were collected in areas of no-tillage (PD), tillage (PC), reforestation (RF) and native forest (MN). In SJ soil samples were collected under native forest (MN), secondary forest (MS), old cropping (LV), new cropping (LN) and abandoned cropping (LA) areas. In JC the samples were collected under native forest (MN), native prairie (CN) and no-tillage (PD) areas. Samples were collected from 0 to 10cm and from 10 to 20cm. Modifications were observed in soil chemical and physical attributes due to the different land uses when compared to the native forest. In systems that do not receive constant external additions, a decrease in soil chemical fertility was observed. Soil organic matter content decreased as the land use intensity increased. C-O-alquyl was the carbon group that presented the largest contribution in the spectra of 13C NMR, independent of the land use system. The main physical alterations observed were the decreases of soil macroporosity, total porosity and saturated hydraulic conductivity and the increase in soil density when compared to soil natural conditions. Soil aggregation parameters did not show to be good indexes to identify changes due to the land use in this study. / As mudanças na utilização das terras podem levar à degradação da qualidade química e física do solo. Nas áreas de encosta do estado do Rio Grande do Sul (RS) a vulnerabilidade à degradação das terras é elevada, devido a combinação de relevo forte ondulado a montanhoso e solos com pequena profundidade efetiva. O objetivo geral deste trabalho foi avaliar as características químicas e físicas do solo de áreas situadas no Rebordo do Planalto na região central do RS, sob diferentes usos da terra. Para isso foram selecionadas duas áreas representativas da região denominada Rebordo do Planalto, caracterizada por áreas de encosta com predomínio da agricultura familiar em pequena escala (Silveira Martins (SM) e São João do Polêsine (SJ)) e uma área de transição entre o Rebordo do Planalto e o Planalto Médio (Júlio de Castilhos (JC)). Em SM foram coletadas amostras de solo no sistema de plantio direto (PD), plantio convencional (PC), reflorestamento (RF) e mata nativa (MN). Em SJ foram coletadas amostras de solo sob os usos na mata nativa (MN), mata secundária (MS), lavoura velha (LV), lavoura nova (LN) e lavoura abandonada (LA). Em JC as amostras foram coletadas em áreas de mata nativa (MN), campo nativo (CN) e plantio direto (PD). As amostras foram coletadas na profundidade de 0-10 e 10-20 cm. Através dos resultados obtidos, observaram-se modificações nas características químicas e físicas do solo em função dos diferentes usos da terra, ao comparar com a mata nativa. Em sistemas que não recebem adições constantes de fontes externas, ocorreu uma depressão da fertilidade química. A matéria orgânica do solo teve diminuição nos teores, conforme aumentou a intensidade de uso da terra. O grupo C-O-alquil foi o grupo de carbono que apresentou a maior contribuição nos espectros de RMN 13C, independente do sistema de uso da terra. As principais alterações físicas ocorridas em comparação com as condições naturais do solo, foram diminuições da macroporosidade, porosidade total e condutividade hidráulica saturada e aumento na densidade do solo. Os parâmetros de agregação do solo, neste trabalho, não se mostraram como bons índices de avaliação para identificar mudanças em função dos diferentes usos da terra.

Les hydrocarbures aromatiques polycycliques (HAP) sont des polluants persistants retrouvés majoritairement dans l’environnement, qui sont reconnus comme hautement toxiques pour les organismes vivants. Les nombreux travaux réalisés sur les mécanismes contrôlant l’évolution des HAP dans le sol et dans la rhizosphère ont mis en exergue le rôle majeur de la biodégradation par les microorganismes et de la sorption aux constituants du sol. Néanmoins, un manque d’informations persiste concernant le devenir de ces HAP dans le sol, et plus particulièrement leur localisation dans les compartiments du sol ainsi que la nature et le comportement des composés issus de leur dégradation. La thèse avait donc comme principaux objectifs : (a) la localisation des HAP et des produits dérivés dans les compartiments du sol (matières organiques, phases minérales, microorganismes et plante), et (b) la quantification et l’identification des composés organiques formant les résidus liés du sol. Pour cela, nous avons couplé deux approches:(i) le suivi d’un HAP modèle marqué, le 13C-phénanthrène (13C-PHE), dans un sol artificiellement contaminé planté et non planté pour notamment déterminer par IRMS et NanoSIMS la distribution du C issu du PHE dans les compartiments et pour identifier les composés dérivés du 13C-PHE par 13C-RMN et TD/pyGCMS. (ii) le suivi d’une contamination ancienne et récente en HAP dans un sol historiquement contaminé pour étudier l’influence des matières organiques et des phases minérales (séparées par un fractionnement densimétrique) dans la rétention des HAP. Plus de 40% du C issu du 13C-PHE est retenu dans le sol après 14 jours de croissance du ray-grass. L’enrichissement en 13C observé dans la plante est du même ordre que celui du sol (E13C ≈ 0.04 % at.) démontrant une incorporation homogène du 13C-PHE entre la plante et le sol. Cet enrichissement global dans la plante est confirmé par les images NanoSIMS réalisées sur les racines. Des hotspots en 13C ont également été observés dans la rhizosphère, et à partir de leur taille, leur forme et leur composition élémentaire en C, N et S ils ont été identifiés comme étant des bactéries, ce qui met en avant leur rôle dans la dynamique des HAP du sol. Dans le sol industriel, la majorité des HAP est retrouvée dans les MO non complexées aux minéraux. En revanche, les HAP fraîchement ajoutés se sont significativement liés aux associations organo-minérales composées de quartz, de feldspaths et de phyllosilicates / Polycyclic aromatic hydrocarbons (PAHs) are major persistent pollutants in the environment that are recognized as highly toxic to living organisms. Numerous studies were carried out on the fate of PAHs in soil and in plant rhizosphere and highlighted the major contribution of biodegradation processes and of the sorption to soil constituents. However, a lack of knowledge remains about the fate of PAHs in the soil and especially their location in soil compartments as well as the nature and the behavior of degradation products. The main objectives of the thesis were: (a) to localize PAHs and their derived products within soil compartments (organic matter, minerals, microorganisms and plant), and (b) to quantify and identify the organic compounds forming bound residues. For this purpose, we used two approaches: (i) the monitoring of a labeled PAH, the 13C-phenanthrene (13C-PHE), in a spiked soil planted or not to determine by IRMS and NanoSIMS the 13C-distribution into compartments and to identify derived compounds of 13C-PHE by 13C-RMN et TD/pyGCMS. (ii) the distribution and localization of aged and freshly spiked PAH contamination in a brownfield soil to study the impact of organic matter and minerals (using soil densimetric fractionation) in the PAH retention. More than 40% of C from 13C-PHE remained in the soil after 14 days of ryegrass growth. The 13C-enrichment in plant tissue was similarly to the soil enrichment (E13C ≈ 0.04 at.%) indicating uniform uptake of 13C-PHE between the soil and plant. NanoSIMS images acquired for roots confirmed this global enrichment in the plant. 13C-Hospots were also observed in the rhizosphere, and on the basis on their size, their shape and their elemental composition in C, N and S, they were identified as bacteria, which emphasize their contribution to the fate of PAHs in soil. In the industrial soil, most of the PAHs were found attached to the free OM. However, the freshly spiked PAHs in the soil were significantly associated with organo-mineral associations containing quartz, feldspars and phyllosilicates

Trees are long living plants, which use carbon from the air and hydrogen and oxygen predominantly from soil water for their growth. They deposit these elements largely into a wood where they may persist for thousands of years. Tree growth is influenced by environment, especially by air temperature and precipitation. These factors have an effect on stomatal conductance and photosynthesis rate which influence carbon stable isotope ratio (13C/12C) in the tree tissue. This thesis is focus on stable carbon isotopes in tree-rings of Norway spruce attacked by honey mushroom, and Norway spruce which doesn?t show any signs of disease. The hypothesis of the thesis is based on an expected difference in carbon isotope fractionation during photosynthesis between the spruce attacked by honey mushroom and a ?healthy? spruce. The difference in isotope fractionation could be caused by water deficit induced by honey mushroom disease in the tree. We expect that the attacked spruce defends against water loss by closing stomata, and it could lead to lower CO2 concentration in the needles and higher ?13C value in tree-rings biomass The stable carbon isotope analysis (IRMS) was done on tree-rings of four spruce pairs, each one including an attacked spruce and spruce which didn?t show any signs of disease. Carbon isotope ratio of early wood, late wood and in biomass of the whole annual increment was measured. In contrary to our hypothesis we did not fined any systematic difference in isotopic composition between the attacked spruce and the spruce which did not show any signs of disease.

In this Ph.D. thesis I am dealing with the effect of dynamic irradiance on (i) photosynthesis, growth and bundle sheath leakiness (for CO2) of C4 plants and (ii) bryophyte photosynthesis. Part of this thesis is literature review on broader aspects of the dynamic light effects on photosynthetic and growth processes in plants.

Les sols sont le plus grand réservoir de carbone des écosystèmes terrestres, et la minéralisation des matières organiques par l’activité microbienne représente la majeure partie des flux de CO2 émis à la surface des continents.Dans ce travail, nous avons étudié les matières organiques extraites à l’eau (WEOM), qui correspondent à la fraction la plus réactive des matières organiques du sol (MOS). Nos objectifs étaient (i) d’identifier les liens de la dynamique du WEOM avec les communautés bactériennes, et avec les paramètres physico-chimiques du sol ; (ii) de réaliser une caractérisation chimique précise du WEOM.Il existe un lien fort entre la solubilité des MOS et les structures des communautés bactériennes, et une baisse de leur diversité impacte la dynamique des MOS et du WEOM, et provoque une baisse de la minéralisation des matières organiques. Une étude à l’échelle régionale a également permis d’identifier que les taux de MOS et d’argile contrôlent les quantités de WEOM et leur aromaticité. La caractérisation au niveau moléculaire a montré la présence d’un grand nombre de molécules ubiquistes dans le WEOM. À partir de ces analyses, nous avons également pu décrire les effets du couvert végétal et des propriétés physico-chimiques des sols sur la composition chimique du WEOM. / Soils are the greatest reservoir of C on the continents, and organic matter mineralisation bymicrobial activity represents the major part of the CO2 emitted by terrestrial ecosystems.In this work, we studied water-extractable organic matter (WEOM), which corresponds to themore reactive fraction of soil organic matter (SOM). Our objectives were (i) to identify therelationships of WEOM dynamics with bacterial communities, and with soil physico-chemicalparameters; (ii) to provide a precise chemical characterisation of WEOM.There is a strong link between SOM solubility and the structure of bacterial communities, andan erosion of their diversity has an impact on SOM and WEOM dynamics, and leads to adecrease in organic matter mineralisation. A study at the regional scale then allowed us to identifythat the SOM and clay contents control the quantities of WEOM and its aromaticity. TheWEOM characterisation at the molecular level revealed the presence of a large number ofubiquitous molecules in the WEOM. Based on these analyses, we were also able to describe theeffects of vegetation and soil physico-chemical properties on the chemical composition ofWEOM.

L’utilisation de molécules issues d’une synthèse maîtrisée est une approche très intéressante pour les biologistes car elle met à leur disposition des molécules bien caractérisées et d’une grande pureté. Dans un premier temps, nous avons synthétisé des triglycérides structurés. Ce sont des molécules lipidiques dans lesquelles les acides gras d’intérêt sont estérifiés sur le squelette glycérol en position connue. Les acides gras introduits appartiennent à la série oméga 3 (acides linolénique (ALA), eicosapentaènoique (EPA) et docosahexaènoique (DHA). Ils sont estérifiés spécifiquement en position interne ou externes car la biodisponibilité des lipides alimentaires, apportés sous forme de triglycérides, varie en fonction de la position de l’acide gras sur le squelette glycérol. L’utilisation de ces lipides structurés a été validée par des études de biodisponibilité, in vivo, chez le rat, qui ont montré que l’ALA était très bien assimilé quelle que soit sa position sur le glycérol. Dans un deuxième temps, nous avons synthétisé un acide a-linolénique fluorescent, sous forme d’ester méthylique, pour obtenir in fine un TG fluorescent. Celui-ci nous permettra suivre, par imagerie, le devenir de l’ALA dans des cellules en culture, modèles de la barrière intestinale. Les différentes molécules synthétisées sont apparues comme un outil fondamental permettant de mieux connaître le devenir métabolique des triglycérides dans l’organisme. / Biologists are very interested in the use of molecules obtained by a well-controlled synthesis because such molecules are well characterized and of high purity. First, we synthesized pure structured triglycerides in other words lipid molecules in which fatty acids are esterified onto a known position of the glycerol backbone. The introduced polyunsaturated fatty acids belong to the omega 3 series (linolenic (LNA),eicosapentaenoic (EPA) and docosahexaenoic (DHA acids). As the bioavailability of lipids depends upon their position on the glycerol skeleton , we prepared triglycerides esterified with omega 3 fatty acids either qt one of the external positions or at the internal one. The use of these structured lipids was validated byr in vivo studies on rats that showed a good assimilation of LNA whatever its position was. Secondly, we synthesized an ? linolenic acid as methyl ester labeled with a fluorophore To obtain in fine a fluorescent triglyceride. This last one will be use for the spatio-temporal follow-up, in culture cell, of the LNA. The synthesized molecules are a promising tool to better understand the triglycerides’ metabolism in the human being.

Mitochondrial isocitrate dehydrogenase 2 (IDH2) catalyzes reductive carboxylation (RC, reverse Krebs cycle pathway) and 2HG synthesis (2HG) - metabolite of which many scientists are interested. 2HG may be concurrently synthetized in cytosol by IDH1. RC is involved in anabolic reactions necessary for cell proliferation - produces citrate, fatty acid precursor - especially in hypoxia. IDH2 and IDH1 are not the only enzymes that are involved in 2HG synthesis. Recently, several enzymes, which participate in 2HG production, have been discovered. 2HG is useful in cancer diagnostics due to its overproduction by transformed cells. Moreover, 2HG may cause epigenetic changes via inhibition of 2-oxoglutarate dependent dioxygenase. In this work, the importance of RC and 2HG synthesis in cancer and healthy cells was investigated by gas chromatography with mass spectrometry detection as well as IDH2 influence. We found that IDH2 significantly participates in reverse RC and 2HG synthesis in breast cancer cell lines and uses glutaminolysis as a supplementary anaplerotic pathway. RC is increased by hypoxia, inhibition of respiration, and decreased by activation of respiration or hypocapnia. We confirmed 2HG synthesis and RC in healthy cells (fibroblasts, breast epithelial cells etc.) as well as in cancer cells....