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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.
61

Estudo de remoção de corantes aniônicos em conchas de moluscos bivalves

PAIVA, Tarsila Maíra Nogueira de 16 November 2015 (has links)
Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2016-07-15T15:52:11Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Tese de Doutorado - Tarsila Maíra Nogueira de Paiva.pdf: 3172020 bytes, checksum: ef23b24c900292b0481d7b9950ba0f46 (MD5) / Made available in DSpace on 2016-07-15T15:52:11Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Tese de Doutorado - Tarsila Maíra Nogueira de Paiva.pdf: 3172020 bytes, checksum: ef23b24c900292b0481d7b9950ba0f46 (MD5) Previous issue date: 2015-11-16 / CAPEs / O potencial das conchas de mariscos anomalocardia brasiliana e ostras crassostrea rhizophorae calcinadas para remoção de corantes têxteis aniônicos foi avaliado e sua eficiência comparada com o carvão ativado comercial. Foi investigado também o tratamento de um efluente real de indústria têxtil, com as conchas, o carvão ativado e um coagulante comercial. Os corantes utilizados foram o Drimaren azul CL-R (CD), o Indosol amarelo SF-2RL (IA), o Lanasyn violeta F-BL 180 (CL) e o Indosol azul turquesa (CI). As conchas e o carvão ativado foram caracterizados através da área superficial, volume e diâmetro médio dos poros, difração e fluorescência de Raios-X, MEV-EDS e pHPCZ. A influência da quantidade de massa e granulometria do adsorvente, salinidade da solução e agitação do processo sobre a capacidade de remoção do sistema foram estudados através de um planejamento experimental. As conchas calcinadas são formadas por 98% de cálcio na forma de óxido de cálcio, suas áreas superficiais estão em torno de 2,0 m2.g-1. O pH em que a carga superficial é zero (pHPCZ) é de 13,0 e 11,5 para as conchas de mariscos e de ostras, respectivamente. O cálcio das conchas interagem com os grupos sulfônicos dos corantes mediante uma reação de simples troca, seguida de precipitação dos corantes. Realizou-se um ajuste não linear para o estudo cinético com as conchas e o carvão ativado, bem como os ajustes de equilíbrio de adsorção com o carvão ativado. O modelo cinético de pseudo-segunda ordem se ajustou bem aos dados experimentais da adsorção. A capacidade máxima de adsorção com o carvão ativado prevista pelo modelo de Langmuir-Freundlich a 30 ºC foi de 157; 361 e 405 mg.g-1 para os corantes CI, CD e Cl, respectivamente. O estudo termodinâmico para o carvão ativado demonstrou que o processo de remoção dos corantes é espontâneo, endotérmico e que a desordem do sistema aumenta com o aumento da temperatura. A eficiência de remoção dos corantes pelas conchas de mariscos e ostras calcinadas em efluentes sintéticos ficou acima de 97 % e 90%, respectivamente aos 5 minutos de reação. A eficiência de adsorção dos corantes utilizando carvão ativado foi acima de 96% no primeiro minuto. No estudo com o efluente real, a quantidade de massa necessária de conchas de ostras calcinadas para remoção de 92,6% foi de 2.000 mg.L-1. Para o carvão ativado atingir esta eficiência, a quantidade requerida foi de 20.000 mg.L-1. As conchas de ostras obtiveram melhor comportamento na remoção de parâmetros como cor, turbidez e demanda química de oxigênio (DQO) quando comparadas a um coagulante comercial e ao carvão ativado. Um tratamento primário é aconselhável antes do descarte ou reuso do efluente tratado para adequação dos níveis da DBO, da DQO e dos ST, aliado ao tratamento secundário com as conchas de mariscos ou ostras calcinadas, para redução da cor e outros parâmetros. A correção do pH é necessária visto que as conchas são de natureza alcalina. As conchas de mariscos e ostras calcinadas mostraram ser materiais eficientes e promissores para remoção de alta concentração de corantes aniônicos comparados com adsorventes ou coagulantes comercias. Elas possuem a vantagem de ser um material natural e necessitar de uma quantidade relativamente pequena para alcançar boa eficiência de remoção. As conchas de mariscos e ostras revelaram-se uma opção atraente na aplicação de tratamento de águas residuais. / The potential of shells brasiliana Anomalocardia clams and oysters Crassostrea rhizophorae calcined to remove anionic textile dyes was assessed and its effectiveness compared with commercial activated carbon. It was also investigated the treatment of a real effluent from the textile industry, with the shells, activated carbon and a commercial coagulant. The dyes used were blue Drimaren CL-R (CD), yellow Indosol SF-2RL (IA), Lanasyn Violet F-BL 180 (CL) and the turquoise Indosol (IC). The shells and activated carbon were characterized by surface area, volume, and average pore diameter, X-rays diffraction and fluorescence, SEM-EDS and pHPCZ. The influence of the amount of mass and particle size of the adsorbent, the solution salinity and bustle of the process on the system removal capacity were studied using an experimental design. The calcined shells are formed by 98% of calcium as calcium oxide, their surface areas are around 2.0 m2.g-1. The pH at which the surface charge is zero (pHPCZ) is 13.0 and 11.5 for the shells of clams and oysters, respectively. The calcium from the shells interact with sulfonic acid groups of the dyes through a single displacement reaction, followed by precipitation of the dyes. We carried out a non-linear fit to the kinetic study with shells and activated carbon, and the adsorption equilibrium adjustments with activated charcoal. The kinetic model of pseudo-second order fits well to the experimental adsorption data. The maximum adsorption capacity with the activated carbon provided by the Langmuir-Freundlich model at 30 °C was 157; 361 and 405 mg.g-1 to IC, CD and CI dyes, respectively. The thermodynamic stud for the activated carbon has shown that the dye removal process is spontaneous, endothermic and that system disorder increases with increasing temperature. The removal efficiency of the dyes by shells of clams and oysters calcined in synthetic wastewater was above 97% and 90% respectively after 5 minutes of reaction. The adsorption efficiency of the dyes using activated carbon was above 96% in the first minute. In the study of the real effluent, the amount of mass needed of calcined oyster shell for removal of 92.6% was 2,000 mg L-1. For the activated carbon to achieve this efficiency, the amount required was 20,000 mg L-1. The oyster shells obtained better performance in the removal of parameters such as color, turbidity and chemical oxygen demand (COD) as compared to a commercial coagulant and activated carbon. A primary treatment is advisable before disposal or reuse of treated wastewater for adequacy of BOD, the COD and ST levels, combined with secondary treatment with the shells of clams or oysters calcined, to reduce color and other parameters. The pH correction is necessary as the shells are of alkaline nature. The shells of clams and oysters calcined showed to be efficient and promising materials for removing high concentration of anionic dyes compared with adsorbents or commercial coagulants. They have the advantage of being a natural material and require a relatively small amount to achieve good removal efficiency. The shells of clams and oysters proved to be an attractive option in the application of wastewater treatment.
62

Investigating the role of Vibrio aestuarianus in summer mortality of farmed Crassostrea gigas in Baynes Sound, British Columbia

Khtikian, Natalie 24 November 2021 (has links)
Marine aquaculture is already vital to global food security and will continue to become more important in the coming years. Crassostrea gigas (Pacific oysters) is the primary oyster species cultivated worldwide. The FAO and IPCC predict that climate change will create uncertainty and challenges for marine aquaculture. Baynes Sound, British Columbia, is a productive region for aquaculture, producing >50% of British Columbia’s total annual bivalve production by live weight and value. Major summer mortality events have been documented in farmed Crassostrea gigas globally since the 1950’s. These events are believed to be caused by a multiplicity of factors including changes induced by anthropogenic climate change. One of the major contributors to summer mortality is the proliferation of Vibrio bacteria, specifically Vibrio aestuarianus, which has been shown to increase in abundance and virulence when seawater temperatures rise. Despite this connection and the economic importance of oyster farming in the region, little is known about the presence of V. aestuarianus in Baynes Sound. Our 17-month study sampled 7 sites in Baynes Sound on 33 occasions from May 2019 to September 2020. We found a positive correlation between seawater temperature and total Vibrio detected in water samples in Baynes Sound, an association that was stronger when the overall temperature regime was warmer. We found no significant correlation between any of the bacterial assays tested and salinity, pH, or Ωarag saturation. We also did not identify a geographic pattern to bacterial abundance or virulence amongst test C. gigas in the field. Understanding that flagellates are the predominant type of microalgae present in Baynes Sound when summer mortality events occur, in lab trials, we found that incorporating V. aestuarianus into marine aggregates with flagellate microalgae caused higher mortality than aggregates with diatoms or planktonic V. aestuarianus. These results were not statistically significant but led us to look at how exposure to husbandry stress pre and post inoculation with V. aestuarianus incorporated into marine aggregates affects mortality. We found that stress was a significant driver of mortality, particularly when administered 24h post inoculation, suggesting that farmers should avoid sorting or tumbling their oysters in the summer, and particularly immediately after a marine heatwave. Oysters lack adaptive immune systems and are grown in an open ocean environment where it is not possible to eliminate their exposure to pathogens. These factors make it impossible to use vaccines or antibacterial disinfectants to combat diseases. Therefore, breeding genetic resistance to V. aestuarianus may be the most effective way to fight summer mortality. Creating a repeatable and accurate protocol for inoculating oysters with marine bacteria is key to accurate heritability measurements and the estimation of breeding values of different families. Key factors include controlling for dose per animal, laboratory efficiency, and inoculation via a mechanism that mimics real-world infection and does not bypass the animal’s immune defenses. We designed a protocol which controls for these factors, separating each animal into individual containers and adding a controlled dose of planktonic bacteria to each. Previously used methods of injection or using an infected “donor” animal in a group tank do not control for dose or bypass parts of the oysters’ natural immune system, potentially creating inaccuracies in survival data generated with these methods. After designing this protocol, we tested 32 full-sib families and estimated the heritability of survival to V. aestuarianus on the observed and underlying liability scales to be 0.095 (SE = 0.043), and 0.15 (SE = 0.068) respectively. We also found a strong negative correlation between oyster size and survival, with a gram of additional weight creating a 73% increase in the risk of death. Fast growth and large size are two traits which have been explicitly bred into C. gigas stock. Our work suggests that breeding a slower-growing, smaller animal may reduce summer mortality. / Graduate / 2022-09-15
63

Étude de la capacité antioxydante en lien avec la reproduction chez l'huître creuse Crassostrea gigas / Study of the antioxydant capacity in link with reproduction in the Pacific oyster Crassostrea gigas

Béguel, Jean-Philippe 20 December 2012 (has links)
Le “coût de la reproduction” est un concept qui définit qu’un investissement à la reproduction élevé a un prix qui se paye ultérieurement par une accélération de la sénescence. Cela peut notamment traduire des compromis entre la reproduction et d’autres fonctions physiologiques comme la défense antioxydante. Chez l’huître creuse Crassostrea gigas, la reproduction représente une fonction physiologique majeure. Dans le cadre des études effectuées pour comprendre les mortalités estivales affectant cette espèce, une corrélation négative entre effort reproducteur et survie a été observée. D’autre part, des gènes antioxydants ont été mis en évidence comme différentiellement exprimés entre les lignées d’huîtres sélectionnées pour leur résistance ou leur sensibilité aux mortalités estivales. Certaines études proposent que la susceptibilité au stress oxydant puisse représenter un coût de la reproduction participant au processus de sénescence. Dans ce contexte, nous avons analysé la capacité antioxydante des huîtres en fonction de leur investissement reproducteur. Pour cela, la technique d’ARN interférence a été utilisée pour manipuler l’effort reproducteur des huîtres. L’expression des principales enzymes antioxydantes (taux de transcrits et activités enzymatiques) et le dosage de dommages oxydatifs ont ensuite été mesurés dans différents tissus et cellules de l’organisme (branchies, gonade, hémocytes et gamètes). Les résultats obtenus dans le cadre de cette thèse suggèrent que la capacité antioxydante de C. gigas est particulièrement efficace et que la reproduction seule n’est pas suffisante pour induire un stress oxydant. Cette capacité antioxydante apparaît comme tissu-spécifique voire cellule-spécifique et le métabolisme du glutathion semble jouer un rôle majeur dans cette protection. Cette grande résistance au stress oxydant contribuerait à faire de C. gigas une espèce particulièrement adaptée à la vie dans des environnements stressants. / The “cost of reproduction” is a concept defining that a high reproductive investment has a price that is paid later by an acceleration of senescence. That may translate tradeoff between reproduction and other physiological functions such as antioxidant defense. In the Pacific oyster Crassostrea gigas, reproduction is a major physiological function. In a study led to understand the summer mortalities affecting this species, a negative correlation between reproductive effort and survival was observed. Moreover, some antioxidant genes were identified as differentially expressed between lines of oysters selected for resistance or susceptibility to summer mortalities. Some studies suggest that the susceptibility to oxidative stress may represent a cost of reproduction taking part to the process of senescence. In this context, we analyzed the antioxidant capacity of oysters according to their reproductive investment. For this, the technique of RNA interference was used to manipulate the reproductive effort of oysters. The expression of the main antioxidant enzymes (transcript levels and enzyme activities) and the dosage of oxidative damages were then measured in different tissues and cells of the organism (gills, gonad, hemocytes and gametes). The results obtained in this thesis suggest that the antioxidant capacity of C. gigas is particularly effective and that reproduction alone is not sufficient to induce oxidative stress. This antioxidant capacity appears to be tissue-specific even cell-specific and glutathione metabolism would to play a major role in this protection. This resistance to oxidative stress would make C. gigas be a species particularly adapted to life in stressful environments.
64

Impacts of Karenia brevis on bivalve reproduction and early life history / Impacts de Karenia brevis sur la reproduction et les stades de vie précoces des bivalves

Rolton, Anne 20 January 2015 (has links)
Karenia brevis, le dinoflagellé produisant des brevetoxines (PbTx), est la principale espèce d’efflorescences d’algues toxiques dans le Golfe du Mexique. Les effets de cette algue sur Mercenaria mercenaria et Crassostrea virginica sont méconnus tandis que les efflorescences coïncident avec la période de reproduction de ces espèces. Ce projet avait pour but de déterminer les effets i) d’une exposition à K. brevis en laboratoire et naturelle de terrain sur les processus physiologiques associés à la reproduction de M. mercenaria et C. virginica, et ii) d’une exposition à K.brevis sur la qualité et le développement des gamètes, embryons et larve de ces espèces. Suite à l'exposition des adultes de clams et d’huîtres à K. brevis, les paramètres physiologiques de la reproduction ont été affectés. La présence de PbTx dans les tissus des gamètes et le potentiel transfert maternel de PbTx à la progénie via les ovocytes, pourraient avoir entraîné les effets négatifs observés lors du développement larvaire.Les effets négatifs similaires causés par l'exposition des stades précoces à différentes préparations de cellules de K. brevis suggèrent que d'autres composés toxiques, en plus de PbTx, pourraient être impliqués dans la toxicité et, que la majorité des effets délétères se produisent durant les divisions embryonnaires.Le clam et l’huître américaine sont sensibles à K. brevis. Les effets négatifs sur les adultes et jeunes stades de vie, combinés à une exposition quasi-annuelle aux efflorescences de K. brevis, pourraient engendrer des perturbations majeures sur le recrutement des populations de ces espèces importantes, et avoir des répercussions environnementales et économiques. / The brevetoxin (PbTx) producing dinoflagellate, Karenia brevis is the most prevalent harmful algal bloom species in the Gulf of Mexico. The effects of this alga on Mercenaria mercenaria and Crassostrea virginica are poorly understood yet, blooms typically overlap with periods of reproduction and spawning in these species.The aims of this project were to determine the effects of i) laboratory and field exposure of K. brevis on the reproductive and related physiological processes of adult M. mercenaria and C. virginica and the quality of the offspring that were produced and ii) K. brevis exposure on gamete, embryo and larval development in these species.Following exposure of adult clams and oysters to K. brevis, negative effects were recorded on reproductive and physiological parameters. PbTx was recorded in gamete tissues, and maternal transfer of this PbTx to the offspring via the oocytes, may have resulted in the significant negative effects recorded on larval development up to the end of the lecithotrophic phase.The similar dose-dependent negative effects caused by direct exposure of gamete and early life stages to different cell preparations of K. brevis suggests that other toxic compounds in addition to PbTx may be involved in toxicity and, that the majority of negative effects occur during embryonic divisions.Hard clams and eastern oysters are susceptible to K. brevis exposure. The negative effects on adult and early life stages combined with the near- annual exposure to blooms of K. brevis could cause significant bottle-necks on the recruitment and population dynamics of these important species and, have wider reaching environmental and economic impacts.
65

Interaction entre l'huître creuse Crassostrea gigas et l'Ostréid herpèsvirus OsHV-1 : influence de la salinité et du pH / Interaction between the Pacific oyster Crassostrea gigas and the Ostreid herpesvirus OsHV-1 : influence of salinity and pH

Fuhrmann, Marine 06 December 2016 (has links)
Crassostrea gigas est l’espèce d’huître la plus cultivée au monde. Depuis 2008, des évènements de mortalité massive touchent les huîtres âgées de moins d’un an en Europe et en Océanie et ont été associés à l’émergence d’un nouveau variant de l’Ostréid herpèsvirus type 1, OsHV-1 μvar. Les huîtres sont naturellement présentes dans les écosystèmes estuariens et côtiers, caractérisés par des fluctuations de salinité et de pH. Dans le cadre de ce travail, l’effet de la salinité (10, 15, 25, 35‰) et du pH (7.8, 8.1) sur la réponse de l’huître à une infection par OsHV-1 a été étudié. La survie d’huîtres acclimatées à une salinité de 10‰ préalablement à l’exposition à une source infectieuse est de 95% et s’explique par une diminution de l’infectiosité d’OsHV-1. En revanche, la survie d’huîtres non-acclimatées simultanément soumises à un choc de salinité à 10‰ et exposées à une source infectieuse n’est que de 23%, ce qui reflète un affaiblissement physiologique. La survie (S) des huîtres aux autres salinités est classée de la manière suivante : S15‰ > S35‰ > S25‰ et selon le pH comme suit : SpH 7.8 < SpH 8.1. Dans les deux études ces contrastes de survie ne sont pas expliqués par un différentiel d’infectiosité du virus mais par celui de la réponse métabolique de l’hôte. Le métabolisme des sucres et l’activité antioxydante d’huîtres acclimatées à 25 et 35‰ sont supérieurs à celui d’huîtres à 10-15‰ et pourraient expliquer leur moindre survie. La plus faible activité antioxydante observée chez des huîtres maintenues à pH 7.8 suggère une production réduite d’espèces réactives de l’oxygène et le maintien d’une production basale d’espèces réactives de l’azote malgré l’infection, ce qui aurait pu réduire la capacité de défense des huîtres face au virus et expliquer leur moindre survie en comparaison à ce qui est observé à pH 8.1. / Crassostrea gigas is the most cultivated oyster species around the world. Since 2008, mass mortality events have been affecting oysters aged less than one year old in Europe, and Oceania and have been associated with a new variant of the ostreid herpesvirus type 1, OsHV-1 μvar. Oysters live in estuaries and bays where they are exposed to fluctuations of salinity and pH. In the present work, the effect of salinity (10, 15, 25, 35 ‰) and pH (7.8, 8.1) on the response of oysters to infection by OsHV-1 was investigated. The survival of oysters acclimated to 10 ‰ prior to be exposed to a source of infection is 95% and is explained by a reduction of OsHV-1infectivity. In contrast, the survival of non-acclimated oysters simultaneously submitted to a salinity stress at 10 ‰ and exposed to a source of infectious is only 23%, likely reflecting physiological impairment. The survival (S) of oysters in other salinity treatment is ranked as follow: S15‰ > S35‰ > S25‰ and according to pH as follows: SpH 7.8 < SpH 8.1. In both studies these contrasts of survival are not explained by differences in OsHV-1 infectivity but in host metabolic response. The carbohydrate metabolism and antioxidant activity of oysters acclimated to 25 and 35‰ is higher than in oysters at 10-15 ‰ and could explain the lower survival. Lower antioxidant activity is observed in oysters maintained at pH 7.8 likely reflecting a reduced production of reactive oxygen species and the maintenance of a basal production of nitrogen reactive species despite infection. This might impair the defense ability of oysters to OsHV-1 explaining the reduced survival at pH 7.8 in comparison to what observed at pH 8.1.
66

Rôle de la température dans l'interaction huître creuse / Ostreid Herpesvirus de type 1 : réponses transcriptomiques et métaboliques / Effects of temperature on the interaction between Pacific oysters and OsHV-1 : transcriptomic and metabolic responses

Delisle, Lizenn 18 December 2018 (has links)
Crassostrea gigas est la principale espèce d’huître cultivée dans le monde. Depuis 2008, de sévères épisodes de mortalités affectent les huîtres âgées de moins d’un an en Europe et en Océanie et sont associées à l’émergence de l’Ostreid herpèsvirus μVar (OsHV-1 μVar). En Europe, ces mortalités sont saisonnières et surviennent lorsque la température de l’eau de mer est comprise entre 16°C et 24°C. Dans le cadre de ce travail, l’effet des hautes températures (21°C, 26°C et 29°C) est évalué sur la sensibilité des huîtres à OsHV-1 mais aussi sur la persistance et la virulence du virus. La survie des huîtres infectées maintenues à 29°C (86%) est supérieure à la survie des huîtres placées à 21°C (52%) et à 26°C (43%).Les températures élevées (29°C) diminuent la sensibilité des huîtres à OsHV-1 sans altérer l'infectivité du virus et sa virulence. L’exposition des huîtres infectées à 29°C pourrait réduire l’expression des gènes viraux et la synthèse de virions par la réduction de l’expression de gènes hôtes codant pour des protéines impliquées dans la transcription et la traduction, la réduction de l’expression de gènes impliqués dans le catabolisme, le transport des métabolites, et synthèse de macromolécules.Finalement, l’induction conjointe de l’apoptose, des processus d’ubiquitinylation et de la réponse immunitaire, pourrait permettre l’élimination d’OsHV-1. / Crassostrea gigas is the main species of oyster cultivated in the world. Since 2008, mass mortality events have been affecting oysters aged less than one year old in Europe and Oceania and have been associated with the emergence of the Ostreid herpes virus μVar (OsHV-1 μVar). In Europe, these events are seasonal and occur when the seawater temperature is between 16°C and 24°C. In this work, the effect of high temperatures (21°C, 26°C and 29°C) was evaluated on the susceptibility of oysters to OsHV- 1 but also on the virulence of virus.High temperatures (29°C) reduce the susceptibility of oysters to OsHV-1 without altering the infectivity of the virus and its virulence. High temperature could reduce viral infection and virus synthesis by reducing the expression of host genes that encode proteins involved in transcription and translation, catabolism, metabolites transport, and macromolecules biosynthesis. Finally, the induction of apoptosis, ubiquitinylation processes and immune response could lead to the elimination of OsHV-1.
67

Políticas Públicas agroecológicas para comunidades quilombolas: um estudo de caso a partir do território / Public Policies for agroecological maroon communities: a case study from the territory

Silva, Rafael Jose Navas da 08 August 2014 (has links)
Com a Constituição Federal do Brasil de 1988, as comunidades remanescentes de quilombos adquiriram direito legal às áreas tradicionalmente ocupadas e o Estado passou a implementar Políticas Públicas visando seu desenvolvimento. Estas Políticas atualmente têm como foco a agroecologia, no sentido de manejo ecológico dos recursos naturais por meio de ação social coletiva. Porém, mesmo os projetos com tal enfoque não têm alcançado os resultados esperados, priorizando apenas a substituição de insumos sintéticos e práticas degradadoras. Considerou-se que o território pode ser um importante instrumento de análise de projetos de agroecologia e que projetos agroecológicos que abrangem as diferentes perspectivas do território têm maiores chances de resultados efetivos para comunidades quilombolas. Assim, o objetivo deste trabalho foi avaliar os Projetos Agroecológicos desenvolvidos na comunidade quilombola Mandira, em Cananéia/SP/Brasil. O trabalho foi realizado entre 2011 e 2014 através de técnicas qualitativas, com entrevistas, observação participante, história oral e análise de documentos. Os projetos analisados foram os relativos à criação da Reserva Extrativista do Mandira e manejo de recursos marinhos, e à implantação de sistemas agroflorestais. O projeto de manejo de recursos marinhos proporcionou inicialmente maior sustentabilidade à atividade e agregação de valor a partir da criação de uma Cooperativa, porém tem mostrado indícios de redução dos estoques naturais, segundo a percepção dos moradores, além da especialização na atividade e redução da produção para autoconsumo. O projeto de sistemas agroflorestais, de abrangência territorial, proporcionou maior diversidade de produtos, tanto para consumo quanto para comercialização, realizada em uma feira agroecológica. As famílias que trabalham com manejo de recursos marinhos possuem maior dependência do mercado, tanto para comercialização, quanto para obtenção de alimentos, diferentemente do outro projeto, que proporcionou maior autonomia, formação de capital social e alimentação saudável. Esses resultados podem confirmar a hipótese de que a perspectiva territorial se constitui um importante instrumento de avaliação de Projetos e também pode contribuir na implementação de ações de Políticas Públicas agroecológicas. / With the Federal Constitution of Brazil of 1988 the remaining maroon communities acquired statutory right to traditionally occupied areas and the Govern started to implement Public Policies aimed at their development. These policies currently are focused on agroecology, in the sense of ecological management of natural resources through collective social action. However, even projects with this approach have not achieved the expected results, just prioritizing the substitution of synthetic inputs and degrading practices. Whereas that the territorial approach involves endogenous and exogenous issues of the relationship between the community and the society, and would offer a greater opportunity of success in the implemented agroecological actions, the objective of this study was to evaluate Public Policies in Mandira maroon community in Cananéia, São Paulo State, Brazil, on these two different perspectives, agroecological and territorial. The study was conducted between 2011 and 2014 using qualitative techniques, including interviews, participant observation, oral history and document analysis. The analyzed projects were those concerning to the establishment of the Mandira Extractive Reserve and management of marine resources, and the implementation of agroforestry systems. The management project of marine resources initially provided greater sustainability to activity and adding value through the creation of a Cooperative, but it has shown signs of stock reduction, as perceived by residents, besides the specialization in the activity and reduction of production for self-consumption. The project of territorial coverage agroforestry systems, provided greater diversity of products, both for consumption and for sale, held in an agroecological fair. Families working with the marine resources management have greater dependence on the market, either for marketing as for obtaining food, unlike the other project, which provided greater autonomy, social capital formation and healthy eating, indicating that the territorial approach in Public Policy agroecological actions can contribute to more effective and sustainable results.
68

Métabolisme énergétique du spermatozoïde d'huître creuse (Crassostrea gigas) / Energy metabolism of Pacific oyster (Crassostrea gigas) spermatozoa

Boulais, Myrina 11 December 2014 (has links)
Cette thèse présente une étude du métabolisme énergétique du spermatozoïde d’huître creuse, Crassostrea gigas. Les principaux objectifs sont (1) d’établir la dynamique des caractéristiques cellulaires et biochimiques du spermatozoïde de cette espèce durant la phase de mouvement, (2) d’identifier les voies de synthèse d’ATP et leurs substrats et (3) de déterminer l’implication du métabolisme énergétique dans le succès à la fécondation du spermatozoïde de cette espèce. Les résultats de ce travail montrent la longue durée du mouvement (de 24 à 72h) du spermatozoïde d’huître creuse et le maintien d’une concentration élevée en ATP intracellulaire, jusqu'à la fin du mouvement. Le rôle de la phosphorylation oxydative (OXPHOS) dans la synthèse d’ATP a été mis en évidence. Le spermatozoïde d’huître creuse montre une grande plasticité dans l’utilisation de ses voies de production d’énergie, assurant la synthèse d’ATP par d’autres voies qu’OXPHOS lorsque la mitochondrie est inhibée. L’accumulation de phosphoarginine en fin de mouvement montre une capacité de stockage de l’ATP synthétisé. La nature des substrats endogènes utilisés pour la synthèse d’ATP reste cependant à déterminer. La forte capacité de régulation du métabolisme énergétique du spermatozoïde d’huître creuse, associée à la possibilité de synthétiser de l’énergie au cours de sa longue phase de nage, contribuent probablement au succès du peuplement observé chez cette espèce. Ce travail apporte une première description du métabolisme énergétique du spermatozoïde d’huître creuse, améliorant la connaissance fine de cette cellule. / The present study aims at describing the energy metabolism of Pacific oyster, Crassostrea gigas, spermatozoon. The main objectives are: (1) describing the kinetic of cellular and biochemical characteristics of Pacific oyster spermatozoon during its movement phase, (2) identifying the metabolic pathways to produce energy and their substrates, (3) determining the involvement of energy metabolism in fertilization success. The results showed the long duration (ranging 24 to 72h) of the movement of Pacific oyster spermatozoon and the maintenance of a high intracellular ATP content until the end of the movement phase. The role of oxidative phosphorylation (OXPHOS) in ATP production was highlighted. Alternative ATP producing pathways might contribute to sustain energy production when OXPHOS is impaired, showing the high adaptation capacity of Pacific oyster spermatozoa. An increase of phosphoarginine content observed at the end of the movement phase suggests energy storage capacity. Endogenous substrates involved in ATP synthesis must be determined. Both the high regulation capacity of the energy metabolism of Pacific oyster spermatozoa and their ability to restore energy stores catabolized during movement likely contribute to the successful settlement observed in the wild. In conclusion, this work provided a fine description of energetic metabolism of Pacific oyster spermatozoon.
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Etude de l’impact de la pollution sonore chez un invertébré marin, l’huître Magallana gigas : approches écophysiologique, écotoxicologique et éthologique au laboratoire et sur le terrain / Impact of noise pollution on a marine invertebrate, the pacific oyster Magallana gigas : ecophysiological, ecotoxicological and ethological study in the laboratory and in the field

Charifi, Mohcine 21 September 2018 (has links)
Les activités humaines font peser sur l’écosystème marin de multiples pressions délétères. Pollution chimique, changement climatique, risque d’acidification, débris de plastique et déchets radioactifs ont des impacts sans précèdent. Une pollution de plus en plus reconnu comme majeur est la pollution sonore. La prospection sismique, le battage de pieux et le trafic maritime génèrent des niveaux sonores qui peuvent être extrêmement forts, modifiant fondamentalement le paysage acoustique sous-marin. On sait que de nombreux mammifères marins et poissons entendent le bruit généré par ces activités et que cela altère leur physiologie et leur éthologie. Par contre, chez les invertébrés marins très peu d’études avaient évalué leur capacité à entendre et l’impact de cette pollution sur eux reste à déterminer. Nous avons abordé le problème par une étude de la capacité de perception du son chez l'huître creuse Magallana gigas en utilisant une approche comportementale et physiologique. Nous avons montré que M. gigas entend dans la gamme de fréquences entre 10 et 1000 Hz. Cette analyse nous a permis de caractériser les sources de sons qui contribuent à leur environnement auditif. Au laboratoire, dans un milieu contaminé (i) au cadmium, un métal que nous avons considéré à la fois comme une substance toxique et un marqueur indirect de l'activité ventilatoire, et (ii), par des bruits de cargo, nous montrons un effet répresseur du bruit caractérisé par une diminution de l'activité valvaire, de l'activité ventilatoire et du taux de croissance. Nous rapportons également une diminution de la bioaccumulation du Cd dans les branchies et une modulation de l'expression de certains gènes. Nous avons enfin étudié sur un enregistrement de 2 ans dans le port commercial de Santander, le comportement (incluant les pontes et la croissance) de 3 groupes d’huitres exposés à une forte pollution sonore et à une « qualité de l’eau » considérée dans la littérature comme bonne à très bonne pour une masse d’eau fortement modifiée. Nous avons retrouvé dans notre analyse différents effets que nous avions provoqués ou prédits à partir du travail de laboratoire où nous avions manipulé le bruit seul. Nous concluons que la pollution sonore au sein du port doit diminuer le fitness des huîtres en modifiant leur activité valvaire, la hiérarchie de leurs rythmes biologiques et la croissance. Nos résultats suggèrent que la pollution sonore peut avoir des conséquences importantes sur les invertébrés et présente un risque fort en termes de productivité de l'écosystème. / Human activities introduce multiple harmful pressures on the marine ecosystem. Chemical pollution, climate change, acidification risk, plastic debris and radioactive wastes have significant effects on marine wildlife. Noise pollution is now recognized as a major source of pollution at sea. Seismic exploration, pile driving and marine traffic, among other activities, generate noise at high sound pressure levels altering the underwater acoustic landscape. Many marine mammals and fish hear the noise generated by these activities which have the potential to alter their physiology and ethology. However, very few studies among marine invertebrates had assessed their ability to hear and the impact of noise pollution on them has yet to be determined. We approached the problem by studying sound perception ability in the pacific oyster Magallana gigas using behavioural and physiological techniques. We have shown that M. gigas is sensitive to sound in the frequency range from 10 to 1000 Hz. This characterization allowed us to define sound sources that contribute to their sound landscape. In the laboratory, in an environment contaminated with (i) cadmium, a metal that we considered to be both a toxic agent and an indirect marker of ventilatory activity, and (ii) cargo ship noise, we showed a depressant or repressant effect of noise characterized by a decrease in valve activity, ventilatory activity and growth rate. We also report a decrease in Cd bioaccumulation and some modulation of gene expression. Finally, we studied a 2-year behavioural record performed in the commercial port of Santander (including spawning events and growth) on 3 groups of oysters exposed to high noise pressure levels. In the port of Santander, the "water quality" is otherwise considered by the literature as good to very good for a heavily modified water body. We found in these records different changes that we previously induced and/or produced in the laboratory. We conclude that the noise pollution load occurring within a commercial port must reduce the fitness of oysters by modifying their valve activity, the hierarchy of their biological rhythms and their growth rate. Our results strongly suggest that noise pollution can have significant consequences on invertebrates and presents a high risk in terms of ecosystem productivity.
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Políticas Públicas agroecológicas para comunidades quilombolas: um estudo de caso a partir do território / Public Policies for agroecological maroon communities: a case study from the territory

Rafael Jose Navas da Silva 08 August 2014 (has links)
Com a Constituição Federal do Brasil de 1988, as comunidades remanescentes de quilombos adquiriram direito legal às áreas tradicionalmente ocupadas e o Estado passou a implementar Políticas Públicas visando seu desenvolvimento. Estas Políticas atualmente têm como foco a agroecologia, no sentido de manejo ecológico dos recursos naturais por meio de ação social coletiva. Porém, mesmo os projetos com tal enfoque não têm alcançado os resultados esperados, priorizando apenas a substituição de insumos sintéticos e práticas degradadoras. Considerou-se que o território pode ser um importante instrumento de análise de projetos de agroecologia e que projetos agroecológicos que abrangem as diferentes perspectivas do território têm maiores chances de resultados efetivos para comunidades quilombolas. Assim, o objetivo deste trabalho foi avaliar os Projetos Agroecológicos desenvolvidos na comunidade quilombola Mandira, em Cananéia/SP/Brasil. O trabalho foi realizado entre 2011 e 2014 através de técnicas qualitativas, com entrevistas, observação participante, história oral e análise de documentos. Os projetos analisados foram os relativos à criação da Reserva Extrativista do Mandira e manejo de recursos marinhos, e à implantação de sistemas agroflorestais. O projeto de manejo de recursos marinhos proporcionou inicialmente maior sustentabilidade à atividade e agregação de valor a partir da criação de uma Cooperativa, porém tem mostrado indícios de redução dos estoques naturais, segundo a percepção dos moradores, além da especialização na atividade e redução da produção para autoconsumo. O projeto de sistemas agroflorestais, de abrangência territorial, proporcionou maior diversidade de produtos, tanto para consumo quanto para comercialização, realizada em uma feira agroecológica. As famílias que trabalham com manejo de recursos marinhos possuem maior dependência do mercado, tanto para comercialização, quanto para obtenção de alimentos, diferentemente do outro projeto, que proporcionou maior autonomia, formação de capital social e alimentação saudável. Esses resultados podem confirmar a hipótese de que a perspectiva territorial se constitui um importante instrumento de avaliação de Projetos e também pode contribuir na implementação de ações de Políticas Públicas agroecológicas. / With the Federal Constitution of Brazil of 1988 the remaining maroon communities acquired statutory right to traditionally occupied areas and the Govern started to implement Public Policies aimed at their development. These policies currently are focused on agroecology, in the sense of ecological management of natural resources through collective social action. However, even projects with this approach have not achieved the expected results, just prioritizing the substitution of synthetic inputs and degrading practices. Whereas that the territorial approach involves endogenous and exogenous issues of the relationship between the community and the society, and would offer a greater opportunity of success in the implemented agroecological actions, the objective of this study was to evaluate Public Policies in Mandira maroon community in Cananéia, São Paulo State, Brazil, on these two different perspectives, agroecological and territorial. The study was conducted between 2011 and 2014 using qualitative techniques, including interviews, participant observation, oral history and document analysis. The analyzed projects were those concerning to the establishment of the Mandira Extractive Reserve and management of marine resources, and the implementation of agroforestry systems. The management project of marine resources initially provided greater sustainability to activity and adding value through the creation of a Cooperative, but it has shown signs of stock reduction, as perceived by residents, besides the specialization in the activity and reduction of production for self-consumption. The project of territorial coverage agroforestry systems, provided greater diversity of products, both for consumption and for sale, held in an agroecological fair. Families working with the marine resources management have greater dependence on the market, either for marketing as for obtaining food, unlike the other project, which provided greater autonomy, social capital formation and healthy eating, indicating that the territorial approach in Public Policy agroecological actions can contribute to more effective and sustainable results.

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