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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Prospecção de fungos derivados de esponjas marinhas na degradação/descoloração de poluentes ambientais. / Prospecting fungi derived from marine sponges on degradation/decolorization of environmental pollutants.

Vasconcelos, Maria Raphaella dos Santos 03 March 2015 (has links)
Diversos estudos têm demonstrado o potencial de utilização de fungos filamentosos na degradação de poluentes ambientais, no entanto, ainda são escassos. O presente trabalho teve como objetivo avaliar o potencial biotecnológico de 174 fungos filamentosos isolados a partir de seis espécies de esponjas marinhas, os quais foram submetidos ao screening em meio sólido contendo corante RBBR e guaiacol; a ensaios em meio líquido, na presença dos corantes preto sulfuroso, índigo blue e reativo black 5, na avaliação da produção das enzimas lacase, manganês peroxidase (MnP) e lignina peroxidase (LiP), utilizando siringaldazina, álcool veratrílico e o vermelho de fenol como substratos enzimáticos, respectivamente; a ensaios de degradação de pireno e benzo[a]pireno; a delineamentos experimentais; e à análise de metabólitos formado na degradação. O fungo selecionado Chaunopycnis alba CBMAI 1346 apresentou 94,54% de degradação em 35 de salinidade, evidenciando o potencial biotecnológico deste fungo em processos de degradação de poluentes ambientais em condições salinas. / Several studies have demonstrated the potential use of filamentous fungi in the degradation of environmental pollutants, however, are still scarce. This study aimed to evaluate the biotechnological potential of 174 filamentous fungi isolated from six species of marine sponges, which were subjected to screening on solid medium containing RBBR dye and guaiacol; the tests in liquid medium in the presence of sulfur black, indigo blue and reactive black 5 dyes, the evaluation of the production of enzymes laccase, manganese peroxidase (MnP) and lignin peroxidase (LiP), using syringaldazin, veratryl alcohol and phenol red as enzyme substrates, respectively; tested for degradation of pyrene and benzo [a] pyrene; the experimental designs; and analysis of metabolites formed in the degradation. The fungus selected Chaunopycnis alba CBMAI 1346 showed 94.54% of pyrene degradation in 35 salinity, highlighting the biotechnological potential of this fungus in the process of degradation of environmental pollutants in saline conditions.
2

Prospecção de fungos derivados de esponjas marinhas na degradação/descoloração de poluentes ambientais. / Prospecting fungi derived from marine sponges on degradation/decolorization of environmental pollutants.

Maria Raphaella dos Santos Vasconcelos 03 March 2015 (has links)
Diversos estudos têm demonstrado o potencial de utilização de fungos filamentosos na degradação de poluentes ambientais, no entanto, ainda são escassos. O presente trabalho teve como objetivo avaliar o potencial biotecnológico de 174 fungos filamentosos isolados a partir de seis espécies de esponjas marinhas, os quais foram submetidos ao screening em meio sólido contendo corante RBBR e guaiacol; a ensaios em meio líquido, na presença dos corantes preto sulfuroso, índigo blue e reativo black 5, na avaliação da produção das enzimas lacase, manganês peroxidase (MnP) e lignina peroxidase (LiP), utilizando siringaldazina, álcool veratrílico e o vermelho de fenol como substratos enzimáticos, respectivamente; a ensaios de degradação de pireno e benzo[a]pireno; a delineamentos experimentais; e à análise de metabólitos formado na degradação. O fungo selecionado Chaunopycnis alba CBMAI 1346 apresentou 94,54% de degradação em 35 de salinidade, evidenciando o potencial biotecnológico deste fungo em processos de degradação de poluentes ambientais em condições salinas. / Several studies have demonstrated the potential use of filamentous fungi in the degradation of environmental pollutants, however, are still scarce. This study aimed to evaluate the biotechnological potential of 174 filamentous fungi isolated from six species of marine sponges, which were subjected to screening on solid medium containing RBBR dye and guaiacol; the tests in liquid medium in the presence of sulfur black, indigo blue and reactive black 5 dyes, the evaluation of the production of enzymes laccase, manganese peroxidase (MnP) and lignin peroxidase (LiP), using syringaldazin, veratryl alcohol and phenol red as enzyme substrates, respectively; tested for degradation of pyrene and benzo [a] pyrene; the experimental designs; and analysis of metabolites formed in the degradation. The fungus selected Chaunopycnis alba CBMAI 1346 showed 94.54% of pyrene degradation in 35 salinity, highlighting the biotechnological potential of this fungus in the process of degradation of environmental pollutants in saline conditions.
3

Impact des hydrocarbures aromatiques polycycliques sur le métabolisme lipidique et le transport du phosphore chez le champignon mycorhizien à arbuscules Rhizophagus irregularis / Polycyclic aromatic hydrocarbons impact on lipid metabolism and phosphorus transport in the arbuscular mycorrhizal fungus Rhizophagus irregularis

Calonne, Maryline 04 December 2012 (has links)
Les hydrocarbures aromatiques polycyliques (HAPs) figurent parmi les polluants organiques persistants majeurs des sols pollués et présentent une toxicité avérée vis-à-vis de l'homme et des écosystèmes. Parmi les méthodes de remédiation des sols pollués par les HAPs, la phytoremédiation assistée par les champignons mycorhiziens à arbuscules (CMA), pourrait représenter une alternative innovante, écologique et économique. L'utilisation des mycorhizes comme outil de phytoremédiation des sols pollués présente plusieurs avantages dont une meilleure tolérance à la toxicité des HAPs, une meilleure nutrition hydrique et minérale ainsi qu'une meilleure dissipation des HAPs. De rares études ont décrit l'impact des HAPs sur le développement des CMA en lien avec une péroxydation lipidique et une perturbation des teneurs en lipides du CMA, mais ni les cibles d'action de ces polluants au niveau du métabolisme lipidique, ni le rôle de ces modifications dans sa tolérance aux HAPs et dans leur dissipation n'ont été étudiés. C'est pourquoi, le premier objectif de ce travail vise tout d'abord à comprendre l'impact des HAPs sur le métabolisme lipidique. Le radiomarquage par l'acétate [1-¹⁴C] a permis de montrer une perturbation de la biosynthèse des lipides membranaires du CMA extra-racinaire. D'autre part, nos résultats montrent que les HAPs affectent la nutrition phosphatée. Par ailleurs, la capacité des mycorhizes à dégrader et à bioaccumuler le benzo[a]pyrène est démontrée. Enfin, l'implication du métabolisme des lipides de réserve (les triacylglycérols) du mycélium extra-racinaire dans la régénération des membranes altérées, la lutte contre le stress oxydant induit par les HAPs et dans leur métabolisation/bioaccumulation est discutée. / Polycyclic aromatic hydrocarbons (PAHs) are among the major persistent organic pollutant frequently found in the polluted soils and are harmful for human health and its environment. To clean-up the PAHs polluted soils, phytoremediation assisted by arbuscular mycorrhizal fungi (AMF) could represent an innovative, ecological and cost-effective alternative. The use of mycorrhizas, as phytoremediation tool, has several advantages including increased tolerance to the pollutant toxicity, improved water and mineral nutrition as well as a better pollutant dissipation. Few studies have described the impact of PAHs on the AMF development related with lipid peroxidation and total lipid content disturbance. However, so far neither the target action of these pollutants on the metabolism, nor the role of these lipid changes in PAH tolerance and in their dissipation have been studied. Therefore, the present work aims firstly to improve our understanding of the PAHs impact on the CMA lipid metabolism. Thanks to radiolabeling experiments with [1-¹⁴C] acetate, our results showed a disruption of the membrane lipid biosynthesis pathways in the AMF extraradical mycelium, grown in the presence of PAHs. Secondly, it was highlighted that the PAHs affectef the phosphate nutrition. Finally, the mycorrhizas abilities to degrade and to bioaccumulate the benzo[a]pyrene, were pointed out. The involvement of extraradical mycelium storage lipid (triacyglycerols) metabolism in the membrane regeneration, the fight against the PAH induced-oxidative stress and the PAH metabolism/bioaccumulation is discussed.

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