This study is divided into four sections beginning with a consideration of the effects of an hitherto undescribed coccidian parasite of the ovary of this bivalve on the dynamics of a particular population from Kames Bay, Millport, Isle of Cumbrae, Scotland. The parasite was found to bring about complete or partial castration of female Tellina tenuis but had no effect on males. The general biology of Tellina-tenuis is reviewed and discussed in relation to observations that were carried out over one year on the age structure, growth, density, reproduction and degree of parasitization of this bivalve. The population parameters were found to have changed little over the last fifty years. There was not found to be any significant change in the condition index that could be related to the destruction of the gonad by the parasite. This is the first description of a coccidian parasite of the ovaries of any marine mollusc. The second section describes the life cycle and developmental stages of the coccidian parasite. The parasite is believed to be monoxenous with sporogony and anisogamy orcurring in the ovary of the host. Endogenous stages were observed in the primary germ cells of the gonadal follicles. A diagnosis is presented based on the number of sprozoites per sporocyst and sporocysts per oocyst. The name Mcrocystis tellinovum (sp. nov. ) is proposed for this coccidian. The genus Merocystis belongs to the family Aggregatidae within the sub-order Eimeriorina of the order Eucoccidiorida. An ultrastructural study of both sexual and asexual stages is presented in support of this diagnosis. The third section of this study is an investigation of the observation that a large proportion of the Tellina tenuis examined histologically contained inclusion bodies within the secretory cells of the digestive gland. These inclusions were comprised of dense masses of pleomorphic mycoplasma-like organisms. The first part of this section describes the morphology and ultrastructure of these organisms and the histopathological effects on the host digestive gland. A description of the normal digestive gland iss-given including observations of the cyclic changes in appearance that take place in response to the influence of tidal rhythms. This is believed to be the first description of a mycoplasma-like organism from a marine invertebrate. The fourth section is concerned with a series of experiments to determine the nature of a virus seen in association with the mycoplasma-like organism. The virus was isolated from the host cells by density gradient centrifugation and its morphology was compared with a second virus isolated by Hill (1975) through the medium of a fish cell culture. It was found that these two viruses were quite distinct from each other. Attempts were made to propagate both viruses in an established cell line from the Atlantic salmon and the results are described and discussed.

Thesis (M. Phil.)--University of Hong Kong, 1996. / Includes bibliographical references (leaf 170-195).

Thesis (Ph.D.)--Memorial University of Newfoundland, 1999. / Restricted until June 2000. Includes bibliographical references.

Thesis (Ph. D.)--University of Washington, 2000. / Vita. Includes bibliographical references (leaves 328-349).

Le but de ce travail de doctorat est d’évaluer la possibilité d’utiliser Haslea ostrearia et la marennine en ostréiculture. Les objectives de ce projet sont : (1) l'évaluation du comportement alimentaire de l'huître creuse Crassostrea gigas sur des cellules d’H. ostrearia de différentes tailles et les conséquences potentielles sur les populations algales; (2) la caractérisation du verdissement par la marennine et ses conséquences sur la physiologie de C. gigas; (3) les conséquences du verdissement sur les traits comportementaux, physiologiques et biochimiques de plusieurs espèces de bivalves; (4) l'utilisation conjuguée d’H. ostrearia avec d'autres microalgues d’importance en aquaculture. Nos résultats suggèrent que la taille des cellules affecte considérablement le processus de selection d’H. ostrearia par l’huître. Cette étude démontre également que la forme extracellulaire de la marenninne contribue significativement au verdissement dans les mucocytes des branchies. Mis à part le verdissement des organes palléaux des bivalves, une concentration modérée de marennine (2 mg L-1) affecte les performances comportementales, physiologiques et biochimiques des bivalves. Néanmoins, ces effets pourraient être compensés par ses activités biologiques comme agent antibactérien naturel et source d’alimentation mixte d’algues en conchyliculture. / This Ph.D. thesis focuses on several assessments to achieve the optimum benefit of utilization of marennine in the field of aquaculture. The study covers: (1) the assessment in feeding behavior of the Pacific oyster Crassostrea gigas on different sizes of Haslea ostrearia and its ecological consequence; (2) the characterization of the greening by marennine and its consequences on some physiological traits of on C. gigas. (3) the consequence of greening by marennine on behavioral, physiological and biochemical traits of bivalves; (4) the utilization of H. ostrearia and marennine in a combination diet with other microalgae relevant to aquaculture.Our results suggest that cell size impacts considerably the selection process of H. ostrearia by oyster. This study also demonstrates that the extracellular form of marennine contributes significantly to the greening in the mucocytes of the gills. Apart from greening the pallial organs of bivalves, marennine (2 mg L-1) affects the behavioural, physiological and biochemical performance. Nevertheless, these effects can be compensated for its biological activities such as natural antibacterial agent and use as a mixed algal diet for bivalve aquaculture.

Made available in DSpace on 2013-08-07T19:13:04Z (GMT). No. of bitstreams: 1 000395848-Texto+Completo-0.pdf: 2738008 bytes, checksum: 39198f00dc6b62c6a5f604fc92b4854b (MD5) Previous issue date: 2003 / Informations on biological and ecological aspects of bivalve molluscs occurring in Mato Grosso State compound the body of this thesis work. Pioneer registers about two species of Anodontites Bruguière, 1792, a Neotropical endemic genus, are considered like: ultrastructural morphology of the shells; populational behavior based on biometrical parameters; gametogenesis and sexual cycle; and patterns related to the selection of feeding particles, filtration rate and respirometry. Using aspects of functional morphology, experimental and population ecology, the main results are: 1. A. trapesialis and A. elongatus present the valves formed by three sheets: periostracum, prismatic and nacreous layers like other Unionoida. Structures like folds, arches, microstriae and spikes are described and differentiated between the species; 2. Comparing the populations sampled in different localities, both species present significant differences in the variants like the shell weight and high being demonstrated that they exhibit phenotypic plasticity according to environmental differences. 3. The two species are spermatozeugmata with continuous gametogenesis during all the year, presenting peaks of production and releasing of gametes during draught and ebbing period. 4. A. trapesialis presents a comparative high filtration efficiency, with the capacity of retaining particles between 0. 5 to 1. 5 g. l-1/h. Parallel to the development of studies on native species, the presence of two invasive bivalve species was detected: Corbicula largillierti (PHILIPPI, 1844) and C. fluminea (MÜLLER, 1774).As a complement to the present thesis, a chapter was added including the history of Corbiculidae invasion in South America, with biometrical data of populations applicable to differentiate both species in the northern limits of Pantanal of Mato Grosso. All this assemblage of informations attempt to mount a base of data to subsidise the elaboration of a program in order to control the biodiversity and monitorate the quality of continental waters, using freshwater bivalves as "sentinel organisms" and as indicators of environmental changes. / Os trabalhos que compõe o corpo desta tese oferecem informações sobre aspectos biológicos e ecológicos de moluscos bivalves que ocorrem no estado de Mato Grosso. Registros pioneiros tratando sobre: 1 - morfologia ultraestrual das conchas, 2 - comportamento populacional frente a parâmetros biométricos, 3 – gametogênese e ciclo sexual, e 4 - padrões relacionados a seleção de partículas, taxa de filtração e respiração, são considerados para duas espécies de Anodontites Bruguière, 1792, gênero de ocorrência exclusiva na América do Sul. Utilizando abordagens de morfologia funcional, ecologia de populações e experimental, os principais resultados obtidos foram: 1 - A. trapesialis (LAMARCK, 1819) e A. elongatus (SWAINSON, 1823) possuem valvas constituídas por três segmentos, perióstraco, camada prismática e camada nacarada, semelhante aos demais Unionoida. Estruturas como pregas, arcos, microsestrias e espículas são descritas e diferenciadas para cada uma das espécies; 2 - quando comparadas populações provenientes de diferentes locais, ambas as espécies apresentaram diferenças significativas frente às variáveis peso da concha e altura, ficando demonstrado que as espécies apresentam plasticidade fenotípica decorrentes de diferenças ambientais; 3 – as duas espécies são espermatozeugmatas, com gametogênese contínua ao longo do ano, apresentando picos de produção e eliminação de gametas durante as estações de vazante e seca; 4 – A. trapesialis apresenta um potencial de filtração com capacidade de retenção de partículas entre 0,5 e 1,5 g. l-1/h.Paralelamente ao desenvolvimento dos estudos com as espécies nativas, foi observada na região, a presença de duas espécies invasoras, Corbicula largillierti (PHILIPPI, 1844) e Corbicula fluminea (MÜLLER, 1774). Como conhecimento complementar à tese, foi acrescentado um capitulo que traz a história da invasão de Corbiculidae na América do Sul e ainda apresenta dados biométricos das populações aplicado para diferenciar as duas espécies no limite Norte do Pantanal de Mato Grosso. Este conjunto de informações pretende compor uma base de dados, visando subsidiar a elaboração de programas de manutenção da biodiversidade e monitoramento da qualidade de águas interiores, utilizando bivalves de água doce como organismos sentinelas e indicadores de alterações ambientais.

Made available in DSpace on 2018-08-24T22:53:22Z (GMT). No. of bitstreams: 1 tese_5985_.pdf: 3322214 bytes, checksum: 3d8e7bb7e84e804e27b3d164733aa92a (MD5) Previous issue date: 2012-04-23 / A região da Ilha das Caieiras, na cidade de Vitória (ES) está localizada no entorno do estuário da Baía de Vitória e próxima a uma extensa área de manguezal urbano. É habitada por uma população que diariamente extrai diversos frutos do mar dessa área para consumo próprio e comercialização. Estudos preliminares realizados recentemente na região já mostraram a contaminação da água e de moluscos bivalves por microrganismos patogênicos provenientes de contaminação fecal. O presente trabalho teve por objetivo ampliar o conhecimento da qualidade microbiológica dos bivalves (sururu de mangue: Mytella guyanensis, sururu de coroa: Mytella charruana e ostra: Crassostrea rhizophorae) procedentes de dois pontos do estuário desta área de manguezal, ao longo de 13 meses de monitoramento (Janeiro/2011 - Janeiro/2012). Foram avaliadas um total de 31 amostras para presença de coliformes termotolerantes (CT) e vírus entéricos (adenovírus AdV; rotavírus RV; e norovírus NoV GII), utilizando-se a nested-PCR e PCR quantitativa em tempo real (qPCR). Também foram avaliados parâmetros físico-químicos da água próxima ao ponto de coleta dos bivalves. Os resultados das análises microbiológicas do sururu de coroa (n=13), sururu de mangue (n=5) e ostra de mangue (n=13) demonstraram alta prevalência de CT, com médias geométricas de 1,47x105, 1,47x105 e 4,24x104 UFC/100g de tecido, respectivamente. Nas amostras de água a concentração de CT apresentou-se em conformidade com o padrão exigido para águas recreacionais. Vírus entéricos foram detectados pela nested e qPCR nos mesmos bivalves com frequências variando entre 31 54% para AdV, 54 70% para RV e 54 85% para NoV GII. A presença de AdV e RV esteve correlacionada positivamente à turbidez e aos sólidos dissolvidos totais (SDT). Nas amostras de água do estuário, os valores máximos quantificados foram 3,0x102, 3,2x104 e 1,6x101 CG/100 mL para AdV, RV e NoV, respectivamente. A elevada contaminação viral e bacteriológica das amostras indica que esta área continua sob impacto antropogênico resultante do despejo de esgoto sanitário na região, e que o consumo de diferentes espécies de bivalves procedentes do manguezal da Ilha das Caieiras apresenta um potencial risco de causar doenças gastrointestinais aos consumidores, especialmente se ingeridos crus.

Inúmeros pesticidas são usados na agricultura, para controle de pragas e ervas daninhas. Dentre eles destaca-se o herbicida atrazina, intensivamente utilizado nas culturas de cana-de-açúcar, milho e sorgo, que ocupam extensas áreas no estado de São Paulo. Grande parcela do herbicida, que é aplicado na agricultura, entra em contato com o solo, podendo ser lixiviado, atingindo as águas superficiais. Neste sentido, alguns animais como, por exemplo, moluscos bivalves, podem ser utilizados como monitores biológicos do ambiente aquático e auxiliar no estudo da ecotoxicologia. Considerando o risco de contaminação do ambiente aquático pela atrazina, propõe-se, no presente trabalho, desenvolver uma metodologia de análise daquele herbicida nos tecidos nas espécies de bivalves límnicos Anodontites trapesialis (LAMARCK, 1819) e Corbicula fluminea (Muller, 1789), validar esse método e, finalmente, verificar se ocorre a bioacumulação do herbicida nas partes moles dessas duas espécies. Como técnica de extração utilizou-se a extração líquido- líquido e como técnica de análise, a cromatografia líquida de alta eficiência (CLAE). / Large amount of pesticides have been used for the control of agriculture pests and weeds. Particularly important among herbicides is atrazine, extensively employed in cultures of sugar cane, corn and sorghum, that occupies an extensive area in São Paulo state. Large portions of atrazine, applied in the agricultural fields, leaches from the soil to surface water systems. In this way, some organisms such as fresh- water mollusks bivalves, can be used as biological monitors of aquatic environments, contributing for ecotoxicology studies. Considering the existence of risk of contamination by atrazine of the aquatic environment, the purpose of this work was, (i) to develop a method for the analysis of atrazine in the fresh- water bivalves species Anodontites trapesialis (LAMARCK, 1819) and Corbicula fluminea (MULLER, 1789), (ii) to validate such method and, (iii) to detect if these organisms can bioaccumulate atrazine in their tissues. This method involved a simple liquid-liquid extraction procedure, followed by high- performance liquid chromatographic analysis (HPLC).

Made available in DSpace on 2014-06-12T18:02:58Z (GMT). No. of bitstreams: 2 arquivo2592_1.pdf: 5032434 bytes, checksum: d14f063d8f3797fef831fdc3580957dc (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2011 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Neste trabalho foram realizadas uma análise taxonômica e paleoecológica dos invertebrados da fauna devoniana da Formação Inajá (Bacia do Jatobá, PE). Os filos estudados foram os Brachiopoda e Mollusca, especificamente, Bivalvia, que respondem pela comunidade dominante na formação. A pesquisa envolveu levantamento bibliográfico, levantamento em coleção paleontológica do Departamento de Geologia da Universidade Federal de Pernambuco (DGEO CTG UFPE), trabalhos de campo e laboratoriais. Os espécimes coletados correspondem a substituições e moldes internos e externos de valvas conjugadas e isoladas. A fauna estudada neste trabalho é composta por 761 exemplares distribuídos entre braquiópodes das ordens Lingulida, Terebratullida e Rhynchonellida com os taxa: Lingula aff. scalprum, Orbiculoidea sp., Camarotoechia jatobensis e Hamburguia sp., e por bivalves das ordens Pterioida, Modiomorphoida, Pholadomyoida, Nuculanoida, Carditoida, Malletiidae com os taxa: Leptodesma (Leptodesma) langei, Spathella brevis, Sanguinolites pernanbucensis, Sanguinolites rochacamposi, Edmondia philipi, Nuculites aff. oblongatus, Streblopteria antiqua, Cypricardella petrolandensis. Estes espécimes foram coletados em quatro localidades Sítio Quixabinha, Saco do Machado, Sìtio dos Nunes, município de Tacaratu - PE e Salinas, município de Petrolândia PE, onde perfis estratigráficos foram levantados e interpretados. Diante de todas as informações sedimentológicas, estratigráficas e paleontológicas levantadas concluiu-se que a Formação Inajá representa um ambiente deposicional marinho proximal dominado por ondas e influenciado por marés, com comunidade dominantemente semiinfaunal e infaunal, com águas moderadamente quentes de salinidade normal e pouco profunda. Uma reconstrução paleosinecológica foi proposta para a Formação Inajá

Les perturbations environnementales peuvent induire des changements au niveau génétique, biochimique et physiologique chez les organismes exposés. Pour faire face à ces perturbations, les bivalves possèdent des défenses antioxydantes telles que la métallothionéine (MT), la superoxide dismutase (SOD), la catalase (CAT), la glutathion peroxidase sélénium dépendante (Se-GPx) et la glutathion S-transférase de classe pi (pi-GST). L'objectif de ce travail est de contribuer à la compréhension des mécanismes de détoxication chez les bivalves d'eau douce Unio tumidus et Corbicula fluminea. Les mollusques bivalves sont largement utilisés comme espèce sentinelle pour étudier la qualité de l'écosystème aquatique. Ce sont des organismes sédentaires, filtreurs, pouvant bioaccumuler une grande quantité de micropolluants environnementaux et qui peuvent être facilement transférés dans des milieux contaminés. La séquence codante de MT de Corbicula fluminea, ainsi que les séquences codantes de MT, SOD et CAT d'Unio tumidus ont été identifiées par RT-PCR en utilisant des amorces dégénérées. L'expression de ces gènes, ainsi que ceux de la Se-GPx et de la GST-pi, a ensuite été étudiée au niveau des ARNm dans différents cas d'études : (i) chez des bivalves prélevés sur une période d'un an dans le but d'identifier une éventuelle variation de l'expression en fonction de la saison, (ii) chez Corbicula fluminea exposée au cuivre et au cadmium, (iii) et chez Unio tumidus transférée au niveau de stations situées le long de la Moselle. Nous avons mis en évidence des variations du niveau d'expression des gènes dues à des paramètres saisonniers tels que la température de l'eau et le cycle de reproduction, principalement chez Unio tumidus. Nos résultats ont montré que les niveaux d'expression des ARNm de MT, SOD, CAT, Se-GPx et GST-pi peuvent être utilisés en tant que biomarqueurs précoces d'exposition au cuivre et au cadmium chez Corbicula fluminea. Des variations d'expression de tous les gènes étudiés ont également été observées chez Unio tumidus, mettant en évidence une anthropisation du milieu aquatique, non détectée par les analyses physicochimiques. Les approches biologiques apparaissent donc comme des outils indispensables à la détection de perturbations environnementales. / Environmental perturbations can induce genetic, biochemical and physiological changes in exposed organisms. To protect from oxidative stress, bivalves possess defences such as metallothionein (MT), superoxide dismutase (SOD), catalase (CAT), selenium-dependent glutathione peroxidase (Se-GPx) and pi class glutathione S-transferase (pi-GST). The aim of this study is to contribute to the understanding of the detoxification mechanisms in the freshwater bivalves Unio tumidus and Corbicula fluminea. Bivalve molluscs are appropriate sentinel species to study the quality of the aquatic environment. They are sedentary, filter-feeding species, bioaccumulating high amounts of environmental micropollutants and can easily be transferred to contaminated areas. The MT coding sequence of Corbicula fluminea and the MT, SOD and CAT coding sequences of Unio tumidus were identified by RT-PCR using degenerated primers. Then, the mRNA expression level of MT, SOD, CAT, Se-GPx and pi-GST was measured in different studies: (i) in bivalves sampled during a 1-year period in order to identify possible seasonal variations of the expression pattern, (ii) in Corbicula fluminea exposed to copper and cadmium, (iii) and in Unio tumidus transplanted in stations located along the Moselle River. Fluctuations of the mRNA level, supposed to correspond to seasonal parameter such as water temperature and reproductive statute, were noted, principally in Unio tumidus. Our results pointed out that MT, SOD, CAT, Se-GPx and GST-pi mRNA expression level could be used as early exposure biomarkers of copper and cadmium exposure in Corbicula fluminea. Variations of gene expression were observed in Unio tumidus, highlighting anthropic impacts on aquatic ecosystem no detected by chemical analysis. Biological approaches appear as essential tools to detect environmental degradations