No description available.

Des antibiotiques sont introduits de façon chronique dans les sols lors de l’épandage des matières fertilisantes d’origine résiduaire (MAFOR), telles que le fumier ou les boues de station d’épuration. La dissémination de ces polluants dans l’environnement présente un risque à long terme pour la santé en raison notamment de l’apparition de résistances aux antibiotiques. L’origine et les propriétés des MAFOR peuvent influencer le devenir ultérieur des antibiotiques dans les sols. Ce devenir et les effets des antibiotiques sur les organismes vivants dépendent de leur (bio)disponibilité. Peu de données existent sur la (bio)disponibilité des antibiotiques dans les sols car elles sont conditionnées par le développement de méthodes d’extraction et d’analyse des molécules à de faibles teneurs, dans des matrices organo-minérales complexes. Ce travail de recherche se focalise sur les liens entre nature des MAFOR, devenir et biodisponibilité des antibiotiques dans les sols, et impacts sur les micro-organismes du sol. Des méthodes chimiques ont été développées pour estimer la (bio)disponibilité et le devenir de deux antibiotiques (ciprofloxacine et sulfaméthoxazole) et de certains produits de transformation dans les sols amendés par des MAFOR et incubés au laboratoire. Un modèle a été utilisé pour décrire le devenir du sulfaméthoxazole et de son métabolite principal dans les sols en fonction de l’évolution de la matière organique de la MAFOR ; ceci a permis de montrer que le co-métabolisme pouvait être à l’origine de la biodégradation des molécules et de la formation de résidus non-extractibles. Enfin, ces données chimiques ont été confrontées à des mesures biologiques : la (bio)disponibilité des antibiotiques mesurée à l’aide de différentes extractions aqueuses a été reliée à leur biodégradation par des micro-organismes adaptés dans les sols ou à leur toxicité sur les activités nitrifiantes microbiennes des sols. Ce travail a permis d’obtenir des résultats originaux qui pourront être utiles pour une évaluation des risques liés à la dispersion des antibiotiques dans l’environnement. / Antibiotics are chronically introduced in soils through the application of exogenous organic matter (EOM) such as manure or sewage sludge. The environmental dissemination of these pollutants presents a long-term risk for health particularly due to the acquisition of antibiotic resistances. The origin and the properties of EOM can influence the antibiotic behavior in soils. This behavior and the potential impact on living-organisms depends on the antibiotic (bio)availability. Few data about the antibiotic bioavailability in soils exist and increasing knowledge is conditioned by the development of extraction and analytical methods for molecules at low concentrations in complex organomineral matrices. This research work focuses on the link between the MAFOR type, the behavior and the bioavailability of antibiotics in soils, and their impacts on soil microorganisms. Chemical methods were developed to assess the(bio)availability and the behavior of two antibiotics (sulfamethoxazole and ciprofloxacin) and some transformation products in EOM-amended soils incubated in controlled conditions. A modelling approach was used to describe the behavior of sulfamethoxazole and its main metabolite in soils as a function of the organic matter evolution; the modelling results suggest that co-metabolism was responsible for the molecule mineralization and the formation of biogenic non-extractable residues. Finally chemical data were confronted to biological measures: the (bio)availability of antibiotics estimated through different aqueous extractions was related to their biodegradation by adapted soil microorganisms or to their toxicity on soil microbial activities. Original results were obtained in this work and will be useful to assess the risk related to the antibiotic dispersion in the environment.

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No. of bitstreams: 1 DissFCP.pdf: 4494134 bytes, checksum: 579efc0cd432aa20fa0626c57daa20b5 (MD5) Previous issue date: 2015-03-27 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / During its evolutionary process, plants have developed biosynthetic pathways by which they produce and accumulate a wide variety of secondary compounds that receive this name because they are not directly involved in the primary processes of plant growth and development. Many of these secondary compounds are responsible for chemical protection of plants against pathogens, herbivores, competing plants, ultraviolet radiation and other environmental stresses. The production of secondary metabolites can vary quantitatively and qualitatively between individuals of the same species, between plants of different species, between organs, between stages of plant development and are under influences of environmental factors. Studies of the biological effects of these compounds represent an important tool for the development of more specific and natural pesticides that are less harmful to the environment, as well as drugs and natural preservatives for food. Myrcia splendens (Sw.) DC. is a tree species found in the Brazilian cerrado and there are few published papers dealing with this species and its secondary metabolites to act as potential natural pesticides, antioxidant and antifungal. The methodology for the extraction of secondary metabolites can determine the composition of extracts and influence the activity of them. In this sense, in the first chapter of this work investigations were carried out on the phytotoxic potential of extracts of M. splendens young leaves from two different extraction methodologies. The 2C extract had the highest overall phytotoxic activity, showing promise in the search phytotoxic substances. In the second chapter, we investigate the phytotoxic potential of extracts and fractions of mature leaves of M. splendens from the two extraction methods carried out and was identified one of the secondary metabolites possibly associated with the phytotoxicity of the most active fractions. 2B fraction had the highest total inhibitory activity and so was fractionated, resulting in 14 fractions, which were also tested in wheat coleoptile. The FM8 and FM9 fractions, which had inhibitory activity and sufficient income, were subjected to HPLC for isolation of major compound. Identification by NMR spectra revealed that the major compound is miricitrin (myricetin-3-O-rhamnoside). In the last chapter, the extracts of mature leaves of M. splendens were tested for their antioxidant potential based on their ability to react with the free radical DPPH (2,2-diphenyl-1-picrylhidrazila) and antifungal potential using the plant pathogenic fungus Alternaria alternata as the target species. Most of the extracts showed a strong antioxidant activity, especially those iv! ! extracted with more polar solvents. On the other hand, only one of the extracts (2B) showed inhibitory activity on mycelial growth of the phytopathogenic fungus tested. / Ao longo do seu processo evolutivo, as plantas desenvolveram rotas biossintéticas pelas quais produzem e acumulam uma imensa variedade de compostos secundários, que recebem este nome por não estarem diretamente envolvidos nos processos primários de crescimento e desenvolvimento vegetal. Muitos desses compostos secundários são responsáveis pela defesa química das plantas contra patógenos, herbívoros, plantas competidoras, radiação ultravioleta e outros estresses ambientais. A produção de metabólitos secundários pode variar quantitativa e qualitativamente entre indivíduos de uma mesma espécie, entre plantas de espécies diferentes, entre órgãos, entre estágios do desenvolvimento vegetal e sobre influências de fatores ambientais. Os estudos realizados sobre os efeitos biológicos destes compostos representam uma importante ferramenta para o desenvolvimento de agroquímicos naturais mais específicos e menos prejudiciais ao ambiente, bem como de medicamentos e conservantes naturais para a indústria alimentícia. Myrcia splendens (Sw.) DC. é uma especie arbórea encontrada no cerrado brasileiro e existem poucos os trabalhos publicados que tratam de investigações do potencial desta espécie e de seus metabólitos secundários para atuarem como pesticidas naturais, antioxidantes e antifúngicos. A metodologia empregada para a extração de metabólitos secundários pode determinar a constituição e rendimento dos extratos e influenciar a atividade dos mesmos. Nesse sentido, no primeiro capítulo deste trabalho foram realizadas investigações sobre o potencial fitotóxico de extratos de folhas jovens de M. splendens oriundos de duas metodologias de extração diferentes. O extrato 2C teve a maior atividade fitotóxica geral, se mostrando promissor na busca de substâncias fitotóxicas. No segundo capítulo, foi investigado o potencial fitotóxico de extratos e frações de folhas maduras de M. splendens das duas metodologias de extração realizadas e foi identificado um dos metabólitos secundários possivelmente associado à fitotoxicidade das frações mais ativas. A fração 2B apresentou a maior atividade inibitória total e por isso foi fracionada, resultando em 14 frações, que também foram testadas em coleóptilos de trigo. As frações FM8 e FM9, que possuíam atividade inibitória e rendimento suficiente, foram submetidas a CLAE para isolamento do composto majoritário. A identificação foi feita por espectros de RMN e revelou que o composto majoritário é a miricitrina (miricetina-3-O-ramnosídeo). No último capítulo, os extratos de folhas maduras de M. splendens foram testadas quanto ao seu potencial antioxidante baseado habilidade de reagir com o radical livre DPPH (2,2-difenil-1-picrilhidrazila) e antifúngico usando como espécie-alvo o fungo fitopatogênico Alternaria ii! ! alternata. A maior parte dos extratos apresentaram atividade antioxidante muito forte, especialmente aqueles extraídos com solventes mais polares. Por outro lado, apenas um dos extratos (2B) apresentou atividade inibitória no crescimento micelial do fitopatógeno testado.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O presente trabalho teve como objetivo geral analisar por CG-EM o óleo essencial de Eucalyptus camaldulensis Denh. influenciado por doses de NPK. A pesquisa justifica-se pela necessidade de se observar a influência da adubação NPK na concentração dos constituintes químicos do óleo essencial de Eucalyptus camaldulensis Denh., já que não existem informações sobre o tema para a espécie em estudo. Coletaram-se as amostras nas primeiras horas da manhã, aproximadamente 07h30min, no campo experimental da Embrapa Roraima. Extraiuse o óleo essencial das amostras coletadas pelo processo de hidrodestilação com sistema tipo Clevenger por 4 horas no Laboratório de Produtos Naturais da Universidade Federal de Roraima. Os óleos voláteis obtidos foram acondicionados em embalagens de vidro âmbar e mantidos resfriados para posterior análise química. Com o auxílio de cromatógrafo a gás Shimadzu acoplado a um detector de espectrometria de massas quadrupolar, QP-5050a, foram realizadas análises cromatográficas, as quais forneceram informações qualitativa e quantitativa. Esses dados quantitativos foram aplicados à modelos estatísticos a fim de se obter informações da influência da adubação NPK na concentração dos constituintes químicos do óleo essencial. Com isso pode confirmar a influencia da adubação NPK, aumentando ou diminuindo, em concentrações da composição química dos grupos hidrocarbonetos monoterpênicos, monoterpenos oxigenados, hidrocarbonetos sesquiterpênicos e sesquiterpenos oxigenados, bem como os constituintes β-pineno e eucaliptol, exceto o p-cimeno, o qual não foi influenciado pelas doses de NPK. Já os constituintes químicos carvacrol, espatulenol e globulol não foram possíveis analisar a influência da adubação NPK para estes compostos químicos. / This study aimed at analyzing by GC-MS of the essential oil of Eucalyptus camaldulensis Denh. influenced by doses of NPK. The research is justified by the need to observe the influence of NPK fertilization on the concentration of chemical constituents of essential oil of Eucalyptus camaldulensis Denh., there is no information on the subject for the species under study. Samples were collected in the first hours of the morning, about 07:30 a.m. in the experimental field of Embrapa Roraima. Was extracted from the essential oil samples by hydrodistillation process with Clevenger-type system for 4 hours at the Laboratory of Natural Products, Universidade Federal de Roraima. The volatile oils obtained were packaged in amber glass bottles and kept refrigerated for later chemical analysis. With the help of Shimadzu gas chromatograph coupled to a detector quadrupole mass spectrometry, QP-5050th, chromatographic analysis was performed, which provided qualitative and quantitative information. These quantitative data were applied to statistical models in order to obtain information on the influence of NPK fertilization on the concentration of chemical constituents of essential oil. This may confirm the influence of NPK fertilization, increasing or decreasing concentrations of the chemical composition of the monoterpene hydrocarbon groups, oxygenated monoterpenes, sesquiterpene hydrocarbons and oxygenated sesquiterpenes as well as the constituents β-pinene and eucalyptol, except the p-cymene, the which was not influenced by the levels of NPK. Since the chemical constituents carvacrol, and espatulenol globulol not been possible to analyze the influence of NPK fertilization for these chemicals.

L'exploration des propriétés santé des riz de Camargue intègre des techniques de pharmacologie in vivo et in vitro, des techniques de fractionnement précises du riz complet et un procédé d'extraction chimique permettant un isolement bio-dirigé des composés bio-actifs.Les résultats du projet de recherche sont confidentiels. / The exploration of health properties of Camargue French rice necessited (a) in vivo and in vitro pharmacological methods,(b) an accurate technology of rice fractionation and (c) the capacity to perform and characterize chemically-extracted bioactive compounds.Results of the research project are confidential.

This thesis focus on investigations of the influence of non-metallic inclusions on corrosion in steel samples taken at different stages of the steel production when producing pipeline steels. The electrolytic extraction technique was used to extract inclusions from these steel samples and thereafter studying them using scanning electron microscopy in combination with energy dispersive microscopy. This approach enabled three-dimensional evaluations of different non-metallic inclusions present in two metal samples of low-carbon Ca-treated pipeline steels. The modification of the inclusion characteristics was investigated and compared for steel samples taken from various stages of the smelting production process. Thereafter, the corrosion resistance of these steels was discussed depending on the characteristics of non-metallic inclusions present in the steel. In addition, this study also presents a new method of soft chemical extraction for qualitative and quantitative evaluations of the initial corrosion processes of a steel matrix surrounding various non-metallic inclusions. The results showed that the initial dissolution of the steel matrix started in areas surrounding CaS inclusions or inclusion phases containing a CaS phase. Furthermore, the results showed that no dissolution of the metal matrix surrounding CaO·Al2O3 and TiN inclusions could be detected.     Key words: pipeline steels, Ca-treatment, non-metallic inclusions, electrolytic extraction, corrosion, chemical extraction. / Sammanfattning Denna avhandling fokuserar på påverkan av icke-metalliska inneslutningar på korrosion i stålprover tagna under olika delar av ståltillverkningsprocessen för tillverkning av rör. Den ektrolytiska extraktionstekniken användes för att extrahera dessa inneslutningar från stålprover och därefter undersöka dem med användande av svepelektronmikroskopi i kombination med energidispersiv spektroskopi. Detta angreppssätt möjliggjorde tredimensionella studier av olika icke-metalliska inneslutningar i två lågkolhaltiga kalciumbehandlade metallprover som används för tillverkning av rör. Modifieringen av inneslutningars karakteristik undersöktes i prover tagna från olika delar av ståltillverkningsprocessen. Därefter så undersöktes motståndet mot korrosion baserat på karakteristiken hos de icke-metalliska inneslutningar som återfanns i stålproverna. Denna studie presenterar också en ny metod baserad på en försiktig kemisk extraktion för kvalitativa såväl som kvantitativa utvärderingar av den initiala korrosionsprocessen av stålmatrisen som omger olika typer av icke-metalliska inneslutningar. Resultaten visade att den initiala upplösningen av stålmatrisen började runt CaS inneslutningar eller komplexa inneslutningar innehållande en CaS fas. Samtidigt så visade resultaten att metallmatriser som omger CaO·Al2O3 och TiN inneslutningar eller faser innehållande dessa inte löstes upp.   Nyckelord: stål för tillverkning av rör, kalciumbehandling, icke-metalliska inneslutningar, elektrolytisk extraktion, korrosion, kemisk extraktion.

Sediment quality guidelines (SQGs) or values (SQVs) are used to assess the potential risk of contaminants in sediment to aquatic organisms, specifically benthic invertebrates. The objectives of this research were to evaluate SQGs derived specifically for use by the uranium industry in Canada, propose alternative SQVs for use at uranium operations in northern Saskatchewan using a novel approach, and investigate the potentially bioavailable fractions of metals in sediment which could become an alternative measurement to the typically used total metal concentrations. The screening-level concentration (SLC) approach has been used in Ontario, Canada, to derive lowest effect levels (LELs) and severe effect levels for use as SQGs. This approach was adopted by the Canadian Nuclear Safety Commission (CNSC) to set guidelines for metals (As, Cr, Cu, Pb, Mo, Ni, Se, U, and V) and radionuclides (Ra-226, Pb-210, and Po-210) in sediment at northern Saskatchewan uranium mining and milling operations. The SLC approach is based on total metal and radionuclide concentrations in sediment, and corresponding benthic invertebrate community composition data for a specific sampling site. In this study, sediment chemistry (total metals and radionuclides) and benthic community data from northern Saskatchewan uranium operations were compiled and examined. Results indicated that the CNSC-derived SQGs had limited relationships to observed effects, or lack thereof, on benthic invertebrate communities near uranium operations in Saskatchewan. On a general basis, the correct alignment of at least one LEL exceedence at an effect site was observed 95% of the time, but on an element-specific basis many of the elements had concentrations at effect sites below their LELs. Furthermore, concentrations of the evaluated elements exceeded at least one LEL at 60% of the no-effect sites. The high number of exceedences of LELs at reference and no-effect sites (false-positives) calls to question the appropriateness of the CNSC-derived SQGs. To address the deficiencies of the SLC approach, a new approach was developed to derive alternative metal SQVs for the uranium industry in northern Saskatchewan that was based on the use of reference and no-effect site field data. Three different sets of NE values were derived using combinations of benthic invertebrate community effect criteria (abundance, richness, evenness, Bray-Curtis index). Additionally, reference (REF) values were derived based solely on sediment metal concentrations from reference sites. In general, NE values derived using abundance, richness, and evenness (NE1 and NE2 values) were found to be higher than the NE values derived using all four metrics (NE3 values). Derived NE values for Cr, Cu, Pb, and V did not change with the incorporation of additional effects criteria due to a lack of influence from the uranium operations on these metal concentrations (i.e., they were generally present at or near background levels). However, a gradient of exposure concentrations was apparent for As, Mo, Ni, Se, and U in sediment which allowed for acceptable exposure levels of these metals in sediment to be defined. The findings from this assessment proposed a set of new, alternate SQVs for use at the uranium industry in northern Saskatchewan. Often, only total metals concentrations are measured in the evaluation of contaminated sediment. However, this measure may over-estimate metal exposure to benthic invertebrates. Using sediment cores collected from near the Rabbit Lake and Key Lake uranium operations, along with a series of mixed-sediments (contaminated and reference sediment), metal bioaccumulation experiments using Chironomus dilutus were conducted in the laboratory. Metal concentrations in extracts from single extractions with either potassium phosphate or hydrochloric acid on wet and dried sediment, pore-water, and whole-sediment were used to evaluate metal bioaccumulation in test organisms. Depending on the metal, pore-water isolated using peepers generally exhibited the best relationship with tissue metal concentrations. Based on this finding, it is suggested that pore-water sampling using peepers (an in-situ dialysis device) be added to environmental sampling programs at Saskatchewan uranium operations so that sediment metal availability to benthic invertebrates can be better assessed. With the eventual development of a larger pore-water metals dataset, SQGs based on pore-water metals concentrations could likely be derived as an alternative to existing SQGs based on total metal concentrations in sediment.

Sediment quality guidelines (SQGs) or values (SQVs) are used to assess the potential risk of contaminants in sediment to aquatic organisms, specifically benthic invertebrates. The objectives of this research were to evaluate SQGs derived specifically for use by the uranium industry in Canada, propose alternative SQVs for use at uranium operations in northern Saskatchewan using a novel approach, and investigate the potentially bioavailable fractions of metals in sediment which could become an alternative measurement to the typically used total metal concentrations. The screening-level concentration (SLC) approach has been used in Ontario, Canada, to derive lowest effect levels (LELs) and severe effect levels for use as SQGs. This approach was adopted by the Canadian Nuclear Safety Commission (CNSC) to set guidelines for metals (As, Cr, Cu, Pb, Mo, Ni, Se, U, and V) and radionuclides (Ra-226, Pb-210, and Po-210) in sediment at northern Saskatchewan uranium mining and milling operations. The SLC approach is based on total metal and radionuclide concentrations in sediment, and corresponding benthic invertebrate community composition data for a specific sampling site. In this study, sediment chemistry (total metals and radionuclides) and benthic community data from northern Saskatchewan uranium operations were compiled and examined. Results indicated that the CNSC-derived SQGs had limited relationships to observed effects, or lack thereof, on benthic invertebrate communities near uranium operations in Saskatchewan. On a general basis, the correct alignment of at least one LEL exceedence at an effect site was observed 95% of the time, but on an element-specific basis many of the elements had concentrations at effect sites below their LELs. Furthermore, concentrations of the evaluated elements exceeded at least one LEL at 60% of the no-effect sites. The high number of exceedences of LELs at reference and no-effect sites (false-positives) calls to question the appropriateness of the CNSC-derived SQGs. To address the deficiencies of the SLC approach, a new approach was developed to derive alternative metal SQVs for the uranium industry in northern Saskatchewan that was based on the use of reference and no-effect site field data. Three different sets of NE values were derived using combinations of benthic invertebrate community effect criteria (abundance, richness, evenness, Bray-Curtis index). Additionally, reference (REF) values were derived based solely on sediment metal concentrations from reference sites. In general, NE values derived using abundance, richness, and evenness (NE1 and NE2 values) were found to be higher than the NE values derived using all four metrics (NE3 values). Derived NE values for Cr, Cu, Pb, and V did not change with the incorporation of additional effects criteria due to a lack of influence from the uranium operations on these metal concentrations (i.e., they were generally present at or near background levels). However, a gradient of exposure concentrations was apparent for As, Mo, Ni, Se, and U in sediment which allowed for acceptable exposure levels of these metals in sediment to be defined. The findings from this assessment proposed a set of new, alternate SQVs for use at the uranium industry in northern Saskatchewan. Often, only total metals concentrations are measured in the evaluation of contaminated sediment. However, this measure may over-estimate metal exposure to benthic invertebrates. Using sediment cores collected from near the Rabbit Lake and Key Lake uranium operations, along with a series of mixed-sediments (contaminated and reference sediment), metal bioaccumulation experiments using Chironomus dilutus were conducted in the laboratory. Metal concentrations in extracts from single extractions with either potassium phosphate or hydrochloric acid on wet and dried sediment, pore-water, and whole-sediment were used to evaluate metal bioaccumulation in test organisms. Depending on the metal, pore-water isolated using peepers generally exhibited the best relationship with tissue metal concentrations. Based on this finding, it is suggested that pore-water sampling using peepers (an in-situ dialysis device) be added to environmental sampling programs at Saskatchewan uranium operations so that sediment metal availability to benthic invertebrates can be better assessed. With the eventual development of a larger pore-water metals dataset, SQGs based on pore-water metals concentrations could likely be derived as an alternative to existing SQGs based on total metal concentrations in sediment.

Frogs, toads, and salamanders are well known for harboring an array of distasteful (and poisonous) secondary metabolites, presumably as antipredator defenses; yet few experiments have rigorously demonstrated the efficacy of amphibian chemical defenses against ecologically relevant consumers. For example, despite an absence of rigorous statistical evidence showing their distastefulness to predators, eastern newts (Notophthalmus viridescens (Rafinesque))--a common salamander in lentic North American habitats--are assumed to tolerate diverse predator assemblages because newts secrete tetrodotoxin (TTX), a neurotoxin. Here we combine laboratory and field-based ecology with bioassay-guided separation of chemical extracts to show that eastern newts--although chemically protected against ecologically important consumers in lentic systems--nonetheless suffer substantial predation when tethered in the field. When offered newts with alternative prey (paedomorphic Ambystoma talpoideum), red swamp crayfish (Procambarus clarkii) and largemouth bass (Micropterus salmoides) were 9-10x as likely to feed on A. talpoideum as newts. Additionally, juvenile bluegill (Lepomis machrochirus) were 70% less likely to consume newt eggs compared to control food pellets. We also show that different newt tissues were differentially palatable to predatory fish. All bluegill tested consumed a palatable control food, but only 20% consumed dorsal skin, only 35% ate ventral skin, but 75% fed on newt viscera, suggesting that deterrent metabolites are concentrated in the skin. Bioassay-guided fractionation revealed that crude and water-soluble newt chemical extracts inhibited bluegill feeding, definitively establishing the chemical nature of newt antipredator defenses, although we were unsuccessful at isolating the chemical compounds responsible for unpalatability. Yet, deterrent activity in the polar but not the lipophilic chemical fraction and bioassay results demonstrating that naıve predators rapidly learn to avoid natural concentrations of TTX support the possible role of TTX in suppressing predation on newts. However, when tethered in the field, newt mortality was 55% higher in ponds with predatory fishes than in ponds lacking fishes (62% vs. 40% respectively), indicating the possible existence of other predators that are resistant to (or tolerant of) newt chemical defenses. Together, these results stress the importance of rigorous, ecologically relevant, and hypothesis-driven experimentation to better understand the complexity of chemically- mediated predator-prey interactions, even for well-studied species like N. viridescens.

No description available.