Environmental genotoxicants/carcinogens in the aquatic environment induce complex detrimental impacts on aquatic organisms. Integrated approach is required to comprehensively assess such impacts in terms of animal and environmental health. Biomarkers at different levels of biological organisations, including clearance rates (at individual level), histopathological alterations (at tissue level), DNA strand breaks using comet assay (at cellular level) and transcriptional alterations of key genes determined by real-time quantitative PCR (at molecular level), were designed and applied to analyse the impacts in marine bivalve: Mytilus sp., a classic bio-indicator species for environmental health monitoring, following exposure to selected environmental contaminants (i.e. Benzo(α)Pyrene (B(α)P), C60 fullerene, and tritium). The performance of biomarkers changed in response to exposures with higher sensitivity for DNA strand breaks and transcriptional alterations of selected genes. In particular, genes representing 7 gene groups (tumour suppressor gene - p53, proto-oncogene - ras, cytochrome P450 family - cyp4y1, MAPKs family - jnk, Bcl-2 family - bax, MDM2 - mdm2 and RAD family - rad51) showed tissue- and chemical-specific expression profiles under selected experimental conditions. A comparison revealed similarity of interplay among these highly conserved genes with mammalian models, suggesting Mytilus sp. could be an ideal model for signalling research in the carcinogenesis process. To my knowledge, this is the first research to detect tissue specific transcriptional alteration of p53 and ras genes in the organism for the analysis of detrimental impacts induced by different environmental genotoxicant/carcinogen exposures. Furthermore, the study is also the first one to include genes which can interplay with each other to function in the regulation of DNA repair, apoptosis and cell cycle arrest in marine organisms. The results suggested that the applied integrated biomarker approach is a comprehensive and sensitive method to monitor environmental health and, marine bivalve Mytilus sp. is an ideal model organism for research on genotoxicant induced carcinogenesis and will shed light on the mechanisms of this complex process in higher organisms, including humans.

Anthropogenic activities are fundamentally altering the chemistry of the world’s oceans. Many of these modifications could have a significant impact on the health of marine organisms. Yet, despite being proposed as one of the most significant threats that marine ecosystems face, to date very little is known about the impact of anthropogenic climate change, and ocean acidification in particular, on host defence. The aims of this thesis are to investigate the impact of environmental stressors on the invertebrate immune response, providing empirical data on how anthropogenically induced stressors will impact the invertebrate immune system and how this will impact organism condition and subsequent physiological trade-offs. Exposure to reduced seawater pH and increased temperature significantly reduced the immune response in the blue mussel, Mytilus edulis. This reduction in immune response could indicate stress-induced immune dysfunction. However, the immune system protects an organism from infectious disease, ensuring survival, and should therefore be evaluated functionally rather than immunologically. By subsequently exposing mussels to a bacterial challenge this study demonstrated that an earlier study which measured a reduction in host defence represented a trade-off of immune system maintenance costs, with mussels maintaining a capacity to up-regulate immune defence when required. However, whilst this immune plasticity ensures mussels are able to survive a pathogen exposure, such a strategy appears to be physiologically costly. This cost is seen as a reduction in reproductive investment, an altered energy metabolism and an altered fatty acid composition in organisms exposed to low pH. Therefore the overarching picture that emerges is, without measuring physiological processes functionally, and in neglecting any physiological trade-offs, it is possible that many studies may misinterpret the complex physiological responses of marine organisms to ocean acidification.

Copper (Cu) is a heavy metal that is essential for life but toxic at high concentrations. This toxic effect is used on boats to prevent biofouling on boat hulls by painting the hulls with antifouling paint that contain high levels of Cu. The Cu is slowly diffused out in the water and accumulated by animals higher up in the food chain. In order to test the effects of marinas on Cu bioaccumulation in invertebrates, I sampled molluscs at seven marinas and seven shore sites on the Swedish west coast. Two molluscs with different feeding behaviours, one grazer, the periwinkle (Littorina littorea) and one filter feeder, the blue mussel (Mytilus edulis) were used as study organisms. Both species were sampled at each location within 50 m from each other. Body Cu concentration of both species was measured with a Flame Atomic Absorption Spectrometer (FAAS). Cu concentration of periwinkle soft body tissue was generally higher than in mussel soft body tissue. In addition, periwinkle tissue Cu concentration reacted strongly positively to the presence of marinas, whereas mussel tissue Cu concentrations did not. This shows that contamination from marinas affects the grazing periwinkle but not the filter feeding blue mussel. Thus, for biomonitoring purposes, grazers may be more suited as indicator organisms.

No description available.

Cyanobacteria produce a variety of secondary metabolites which possess amongst others antifungal, antibacterial, and antiviral properties. Being primary producers they are also a vital component within the food web. However, certain strains also produce toxic metabolites such as the hepatotoxins microcystin (MC) and nodularin (NOD). Their toxicity in combination with the increasing global occurrence has resulted in a drinking water guideline limit of 1 μg L-1 being issued by the World Health Organisation (WHO). However, these toxins are not only present in water, but can be accumulated by fish and shellfish. Currently, no regulations regarding cyanotoxin contaminated seafood has been established despite similar toxicity to routinely monitored marine toxins such as domoic acid (DA). To facilitate regular monitoring, a high performance liquid chromatography photo diode array (HPLC-PDA) analysis method for the detection of DA was optimised to enable the simultaneous detection of DA and nine cyanotoxins. This method was then utilised to determine cyanotoxin concentration in laboratory cyanobacteria strains. To assess the accumulation and depuration of cyanotoxins in the common blue mussel Mytilus edulis, three feeding trials were performed. During these, mussels were exposed to two cyanobacteria strains, Nodularia spumigena KAC66, Microcystis aeruginosa PCC 7813, both individually and simultaneously. A rapid dose dependent accumulation of cyanotoxins was observed with maximum concentration of 3.4 -17 μg g-1 ww accumulated by M. edulis, which was followed by a much slower depuration observed. During the final feeding trial, with N. spumigena KAC 66 and M. aeruginosa PCC7813, cyanotoxins were still detectable following 27 days of depuration. Mortality in all studies was 7% or less indicating that most mussels were unaffected by the maximum dose of 480 μg L-1 NOD (feeding study 1), 390 μg L-1 MC (feeding study 2), or 130 μg L-1 total cyanotoxins (feeding trial 3), respectively. Mortality in negative control tanks was lower throughout all three feeding trials ( < 1 - 2.6%). Consumption of a typical portion size (20 mussels) would result in ingestion of cyanotoxins at levels significantly higher than the WHO recommended tolerable daily intake (TDI) of 2.4 μg NOD and/or MCs for a 60 kg adult. This value was exceeded not only during the exposure period (maximum levels 270 - 1370 μg cyanotoxins per 20 mussels), but also at the end of the depuration period 39-600 μg cyanotoxins per 20 mussels. These results illustrated that cyanotoxin monitoring of seafood should be considered not only during, but also following bloom events. In an attempt to investigate the cyanotoxin budget of the experimental system, not only mussels, but cyanobacteria cultures, the tank water, and the mussel faeces were also analysed for their cyanotoxin content. Results showed that large quantities of MCs and NOD were unaccounted for during all exposure trials. The combined effect of cyanotoxin metabolism in M. edulis, biotic and/or abiotic degradation, protein binding, and losses during the extraction and analysis were thought to have contributed to the unaccounted cyanotoxin fraction. Mussel flesh was analysed for the presence of glutathione or cysteine conjugates, however, there was no evidence of their occurrence in the samples tested. Due to these discrepancies in the toxin budget of the system, the introduction of correction factors for the analysis of cyanotoxins in M. edulis was suggested in order to protect the general public.

Resumo: O processo limitante na produção de mudas de algumas palmeiras é a germinação, pois, suas sementes perdem a viabilidade rapidamente depois de colhidas. Essa pesquisa teve como objetivo avaliar o armazenamento de plântulas de Euterpe edulis em câmara fria a 100C (0, 3, 6 e 9 meses), em diferentes estádios de desenvolvimento (de zero a dez semanas do início do processo germinativo), visando a obtenção de plântulas ao longo do ano. Foram coletadas amostras de cada tratamento para a determinação da atividade da peroxidase, envolvida no germinação de sementes, desenvolvimento de plântulas e também, ligadas ao estresse e senescência, possibilitando avaliar os efeitos na fisiologia das sementes provocados pelos tratamentos. Foi observado o desenvolvimento vegetativo das sementes e/ou plântulas após os tratamentos em condições de casa de vegetação, por período de 6 meses, para determinar a taxa de sucesso (plântulas com desenvolvimento normal). A taxa de sucesso de plântulas foi afetada negativamente pela permanência das sementes/plântulas em câmara de germinação e armazenamento em câmara fria. Dos parâmetros morfológicos de desenvolvimento analisados no final do experimento (comprimento de parte aérea, comprimento de parte aérea total, comprimento de raiz, diâmetro do coleto, massa de matéria fresca e massa de matéria seca), somente ocorreu diminuição do comprimento da raiz, sob estas condições. A atividade da peroxidase aumentou em decorrência do aumento do período de armazenamento em câmara fria, relacionada com a senescência das plântulas. Apesar da redução da taxa de sucesso das plântulas, não ocorreu redução dos parâmetros de desenvolvimento vegetativo (exceto comprimento de raiz) analisados das sementes/plântulas, portanto, o armazenamento em câmara fria é um instrumento viável para prolongar o período de uso das sementes de Euterpe... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Germination is the limiting process in the seedling production of some palm trees, since their seeds lose viability rapidly after collection. This study aimed to evaluate the storage of Euterpe edulis seedlings in a cold chamber at 10ºC (0, 3, 6 and 9 months) at different developmental stages (from zero to ten weeks after the initiation of the germinative process) in order to obtain seedlings throughout the year. Samples from each treatment were collected for assay of peroxidase activity, involved in seed germination, seedling development and also related to stress and senescence, which allows evaluating the treatment effect on seed physiology. The vegetative development of seeds and/or seedlings was observed under greenhouse conditions for six months to determine the success rate (seedlings presenting normal development). The success rate of seedlings was negatively affected by the maintenance of seeds/seedlings in germination chamber and storage in cold chamber. Among the morphological traits of development analyzed at the end of the experiment (shoot length, total shoot length, root length, stem diameter, fresh matter and dry matter), only root length decreased under such conditions. Peroxidase activity increased due to the longer period of storage in cold chamber, which was related to the senescence of seedlings. Despite the reduction in the success rate of seedlings, there was no decrease of vegetative developmental traits (except root length) analyzed in seeds/seedlings. Therefore, the storage in cold chamber is a viable instrument to extend the use of seeds for propagation of Euterpe edulis / Orientador: Ana Catarina Cataneo / Coorientador: Edson Seizo Mori / Banca: João Nakagawa / Banca: Leonardo Cesar Ferreira / Mestre

Submitted by Jorge Silva (jorgelmsilva@ufrrj.br) on 2017-04-05T20:08:44Z No. of bitstreams: 1 2016 - Diego Renan Sobreiro Falc?o Paim.pdf: 1171234 bytes, checksum: 293452c2fece2086e9010a78bb8b4db1 (MD5) / Made available in DSpace on 2017-04-05T20:08:44Z (GMT). No. of bitstreams: 1 2016 - Diego Renan Sobreiro Falc?o Paim.pdf: 1171234 bytes, checksum: 293452c2fece2086e9010a78bb8b4db1 (MD5) Previous issue date: 2016-03-07 / CAPES / This study aimed to obtain a product in probiotic powder to ju?ara base, whose palm is being threatened with extinction due to indiscriminate practice of palm heart extraction and, in this sense, add value to this fruit is a proposal in an attempt to preserve the species. Initially, ju?ara pulp added probiotic microorganism Bifidobacterium spp. lactis was subjected to drying by spray drying (spray drying), which promoted a microencapsulation. In this first step, differet types and combinations of carriers agents were evaluated, totalizing four formulations: maltodextrin, maltodextrin + inulin (1:1), maltodextrin + oligofructose (1:1) and maltodextrin + inulin + oligofructose (2:1:1). The samples produced with different formulations were characterized in relation to the viable cell count, phenolics, anthocyanins, ABTS + antiradical activity, density, porosity, particle size and hygroscopicity. The samples produced with maltodextrin + inulin (1: 1) showed the best results, being selected for further stability study. In this study, samples were also produced by freeze drying, in order to compare the processes. The powders produced by the two processes were stored at different temperatures (7 and 35 ? C) and evaluated periodically for 60 days. Results showed that the samples stored at 7?C showed microorganism cell count higher than 107 CFU/g after 60 days of storage, being considered as probiotic products, whereas samples stored at 35?C showed cell counts lower than 104 CFU/g after 30 days. The samples produced by freeze drying showed higher viable cell counts compared to those produced by spray drying, after 30 days of storage. Regarding the phenolic content and antirradical activity, the samples showed a very similar behavior to each other. / Este trabalho teve como objetivo a obten??o de um produto em p? probi?tico ? base de ju?ara, cuja palmeira vem sendo amea?ada de extin??o devido ? pr?tica indiscriminada do extrativismo do palmito e, nesse sentido, agregar valor a esse fruto ? uma proposta, na tentativa de preservar a esp?cie. Inicialmente, a polpa de ju?ara adicionada do microrganismo probi?tico Bifidobacterium spp. lactis foi submetida ao processo de secagem por atomiza??o (spray drying), que promoveu sua microencapsula??o. Nesta primeira etapa, foram avaliados diferentes tipos e combina??es de agentes carreadores, totalizando quatro formula??es: maltodextrina, maltodextrina + inulina (1:1), maltodextrina + oligofrutose (1:1) e maltodextrina + inulina + oligofrutose (2:1:1). As amostras produzidas com as diferentes formula??es foram caracterizadas em rela??o ? contagem de microrganismos vi?veis, fen?licos totais, antocianinas, atividade antirradical ABTS+, densidade, porosidade, higroscopicidade e tamanho de part?culas. As amostras produzidas com maltodextrina + inulina (1:1) foram as que apresentaram os melhores resultados, sendo selecionadas para o posterior estudo de estabilidade. Nesse estudo, as amostras foram produzidas tamb?m por liofiliza??o, a fim de se comparar os processos. O produto em p? produzido pelos dois processos foi estocado a diferentes temperaturas (7 e 35?C) e avaliado periodicamente, durante 60 dias. Os resultados mostraram que as amostras estocadas a 7?C apresentaram contagem de microrganismos superior a 107 UFC/g ap?s 60 dias de estocagem, podendo ser consideradas probi?ticas, enquanto as amostras armazenadas a 35?C apresentaram contagem inferior a 104 UFC/g a partir de 30 dias. As amostras produzidas por liofiliza??o apresentaram maior contagem quando comparadas ?s produzidas por atomiza??o, a partir de 30 dias de estocagem. Em rela??o ao teor de fen?licos e ? atividade antirradical, as amostras apresentaram comportamentos muito semelhantes entre si.

The practice of slash-and-burn is the basis of traditional agriculture in the tropics and subtropics and in recent years has become unsustainable. The adoption of alternative techniques as improved fallow and slash-and-mulch can promote productivity and provide great potential for sustainability of agricultural systems in Eastern Amazon. The improvement of fallow vegetation with tree legumes can promote accumulation of biomass and nutrients at higher levels than spontaneous fallow, affecting positively the productivity of agricultural crops. The grinding of biomass stocks minimizes the negative of fire effects improving chemical, physics and biological soil quality. This study aimed to compare biomass and nutrient stocks of the shoot, litter, fine and intermediate roots of a 23 months fallow vegetation under different managements: (1) natural fallow, (2) enriched fallow with leguminous trees (Sclerolobium paniculatum Vogel and Inga edulis Mart.) and (3) natural vegetation enriched with leguminous trees under phosphorus low solubility fertilization, and addition assess the effects of treatments on soil quality. The experiment was conducted for 36 months in a slash-and-mulch system, in the São João community, Marapanim, Eastern Amazonia. The results showed that the management of fallow vegetation accumulated greater amounts of biomass and nutrient stocks and the sequence fallow-crop of slashand-mulch system improves soil quality. / A prática de derruba-e-queima é base da agricultura tradicional nos trópicos e subtrópicos e nos últimos anos tem se tornado insustentável. A adoção de técnicas alternativas à queima aliadas ao manejo da vegetação de pousio podem promover a produtividade e apresentar grande potencial para a sustentabilidade de sistemas agrícolas na região do Nordeste Paraense. O enriquecimento da vegetação de pousio com leguminosas arbóreas pode promover o acúmulo de biomassa e nutrientes em níveis superiores ao pousio espontâneo, influenciando positivamente na produtividade das culturas agrícolas. A trituração da biomassa acumulada minimiza os efeitos negativos causados pelo fogo melhorando características químicas, físicas e biológicas do solo. Este trabalho tem como objetivo comparar estimativas da biomassa e estoques de nutrientes da parte aérea, serrapilheria, raízes finas e intermediárias de vegetação de pousio de 23 meses submetida a diferentes manejos de vegetação de pousio: (1) vegetação de pousio espontâneo, (2) pousio enriquecido com leguminosas arbóreas (Sclerolobium paniculatum Vogel e Inga edulis Mart.) e (3) pousio enriquecido com leguminosas arbóreas submetidas à adubação fosfatada de baixa solubilidade, e ainda avaliar os efeitos dos tratamentos sobre a qualidade do solo. O experimento foi conduzido por 36 meses, em um sistema agroflorestal seqüencial de corte-e-trituração na comunidade de São João, município de Marapanim, Amazônia Oriental. Os resultados mostraram que o manejo da vegetação de pousio acumula maiores quantidades de biomassa e estoques de nutrientes em relação ao pousio espontâneo e a seqüência do sistema de corte-e-trituração de pousio-cultivo, melhora a qualidade solo.

L'histoire de l'ostréiculture française met en évidence la fragilité de cette production face à la surexploitation des stocks et l'apparition de maladies. En particulier, la production d'huître plate, Ostrea edulis, a fortement diminué suite à l'apparition de deux maladies parasitaires dont la bonamiose. Les moyens de lutte contre la bonamiose sont relativement restreints. Ils sont essentiellement basés sur la surveillance de la santé des huîtres afin de limiter la dissémination et la propagation de la maladie. Cependant l'utilisation de modèles prédictifs de l'évolution de la maladie en zone infectée permettrait d'optimiser la gestion des stocks et minimiser l'impact des agents pathogènes. De plus, le développement d'animaux résistants à l'infection pourrait permettre de relancer cette production. Ces différentes approches nécessitent des outils diagnostiques adaptés, une bonne connaissance du cycle de vie de l'agent pathogène, et, plus particulièrement des interactions du parasite avec son hôte. Dans ce contexte, l'objectif principal du travail de thèse proposé est de comprendre les interactions entre l'huître plate Ostrea edulis et son parasite Bonamia ostreae, et, plus particulièrement les bases moléculaires de la résistance au parasite. Dans un premier temps, la réalisation d'une banque soustractive d'ADNc a permis d'identifier des ESTs différentiellement exprimées chez des hémocytes en réponse au parasite. L'expression de certains gènes dont une galectine a été mesurée en PCR en temps réel dans le contexte d'infections in vitro. En complément, la réponse cellulaire a été étudiée par cytométrie en flux et l'infection contrôlée en microscopie. Ces expériences ont montré une multiplication parasitaire dans les hémocytes au cours du temps associée à une diminution de la production d'EOR et d'estérases. Dans un second temps, il a été entrepris une étude comparative entre une population d'huîtres plates résistantes à la bonamiose et une population naturelle. Les résultats obtenus tendent à montrer qu'une modulation de l'apoptose et une diminution de la phagocytose seraient impliquées dans les mécanismes liés à la résistance à la bonamiose. Ce travail est le premier à étudier la réponse des hémocytes d'huîtres plates à une infection par le parasite Bonamia ostreae au niveau cellulaire et moléculaire.

Thesis (M.Sc.)--Memorial University of Newfoundland, 2005. / Bibliography: leaves 78-90.