O objetivo deste trabalho foi analisar a distribuição espaço-temporal de um representante da macrofauna de praias arenosas protegidas. As abordagens em diferentes escalas (mesoescala, microescala e escala temporal) foram empregadas. O gastrópode Olivella minuta, abundante na região entremarés da Baía do Araçá, foi utilizado para essas análises. Para o estudo em mesoescala, 16 estações foram demarcadas na região entremarés (julho/2009) e, em cada uma, foram coletadas 8 amostras biológicas e 3 de sedimento. Alguns fatores abióticos (carbonato de cálcio, matéria orgânica e coeficiente de seleção) influenciaram negativamente a abundância do gastrópode, enquanto relações entre O. minuta e as demais espécies da macrofauna não foram evidentes. Em microescala, em poças de maré (metros) e em \"ripple marks\" (centímetros) verificou-se que em escala de centímetros, o gastrópode foi mais abundante em locais com maior conteúdo de água no sedimento, enquanto em escala de metros a abundância não diferiu dentro e fora das poças. Em escala temporal, foram observadas flutuações mensais da densidade da população de O. minuta, com diminuição/ausência de indivíduos entre fevereiro e março, o que sugere a ocorrência de migrações e mortalidade. O presente trabalho mostrou que a distribuição desse gastrópode é influenciada por diferentes fatores que atuam em diferentes escalas. / The objective of this study was to analyze the temporal and spatial distribution of one of the species representative of the macrofauna of sheltered sandy beaches. Measurements using different scales (mesoscale, microscale and time scale) were utilized. The gastropod Olivella minuta, which is abundant in the intertidal region of Baía do Araçá, was used for these analyses. For the mesoscale study, 16 stations were determined within the intertidal region (July/2009) and, in each station, 8 biological samples and 3 samples of sediment were collected. Some abiotic factors (calcium carbonate, organic matter and selection coefficient) had a negative influence on the abundance of the gastropod, while relationship between the O. minuta and other species of the macrofauna were not evident. In a microscale study of tidal ponds (meters) and ripple marks (centimeters), it was observed that, in a centimeter scale, the gastropod was more abundant in places where there was more water in the sediment, whereas in a meter scale the abundance didn\'t vary in or out of the ponds. In a temporal scale, monthly fluctuations of the O. minuta population\'s density were observed, with reduction/absence of individuals between February and March, which suggests that migration and mortality occurred. This study showed that the distribution of O. minuta is influenced by different factors which act in different scales.

Praias arenosas são caracterizadas por uma abundante macrofauna, composta por poliquetas, moluscos e crustáceos. Dentre os moluscos, os gastrópodes constituem um dos grupos mais conspícuos. Entretanto, as informações sobre esse grupo em praias são escassas e se referem principalmente à ocorrência em comunidades. O neogastropoda Olivella minuta é comum e abundante em praias do Litoral Norte de São Paulo. Porém, há importantes lacunas no conhecimento quanto à distribuição desta espécie. Diante desse cenário, o presente estudo visou analisar a distribuição espaço-temporal de Olivella minuta na praia de Barequeçaba, bem como os fatores ambientais relacionados a essa distribuição. Para análise da distribuição espacial de O. minuta ao longo do entre-marés da praia, amostras foram obtidas em outubro de 2009, a partir de doze estações perpendiculares à linha da água, compostas por três transectos com seis níveis cada. Os fatores abióticos (características do sedimento) e bióticos (descritores da macrofauna) que compõem cada estação também foram amostrados e relacionados com a distribuição da espécie. Os resultados revelaram que os indivíduos ocorreram em maior densidade na porção sul da praia, e nos ambientes mais úmidos, próximos a linha da água. O carbonato de cálcio e a matéria orgânica foram os fatores mais determinantes, contrastando com a hipótese de que há influência tanto dos fatores abióticos quanto dos bióticos em tal distribuição. Para análise de distribuição temporal de Olivella minuta no eixo vertical da praia, amostras foram obtidas mensalmente no entremarés, a partir de cinco transectos aleatórios estabelecidos perpendicularmente à linha da água, com nove unidades amostrais. Além disso, amostras foram obtidas trimestralmente, no entremarés e infralitoral, a partir de cinco transectos aleatórios, compostos por nove e seis níveis amostrais, respectivamente. Os resultados revelaram um padrão de distribuição da espécie no entremarés ao longo do tempo, e confirmaram a hipótese de que há uma distribuição de O. minuta de acordo com o tamanho do indivíduos no eixo vertical da praia, com indivíduos menores ocorrendo apenas no infralitoral e migrando para o entremarés ao longo de sua ontogenia. Os avanços apresentados no presente estudo contribuem para o conhecimento sobre a ecologia de populações de praias arenosas, ao relacionar a distribuição de uma espécie da macrofauna com os fatores ambientais, e principalmente ao abranger o infralitoral nas amostragens, por tratar da distribuição de uma espécie cuja distribuição não é exclusiva do entremarés / Sandy beaches have typically abundant macrofauna, comprised of polychaetes, mollusks, and crustaceans. Among mollusks, gastropods comprise one of the most conspicuous groups. Nevertheless, data on this group for beaches are scarce and refer mainly to their occurrence in communities. The neogastropoda Olivella minuta is common and abundant on beaches along the Northern Coast of São Paulo. However, there are important gaps in the knowledge regarding the distribution of this species. Based on this scenario, the present study aims at analyzing the distribution of Olivella minuta in space and over time on Barequeçaba Beach, as well as the related environmental factors. To analyze the distribution of Olivella minuta along the intertidal zone of the beach, samples were obtained in October 2009 from twelve stations perpendicular to the waterline, comprised of three transects with six levels each. Abiotic (sediment characteristics) and biotic (macrofauna descriptors) factors that comprise each station were also sampled and linked to distribution. Results showed that there was higher density of individuals in the southern part of the beach, and in more humid environments, closer to the waterline. Calcium carbonate and organic matter were the most determining factors in the species\' distribution, as opposed to the hypothesis that both abiotic and biotic factors were influencing factors. To analyze the distribution of Olivella minuta over time in the vertical axis of the beach, samples were collected monthly in the intertidal zone, from five random transects set out perpendicularly to the waterline with nine sampling units. In addition, samples were also obtained quarterly with five random transects comprised of nine and six sampling levels in the intertidal zone and in the infralittoral zone, respectively. Results showed a distribution pattern for the species in the intertidal zone over time and confirm the hypothesis that O. minuta is distributed along the vertical axis of the beach according to the size of individuals, with smaller individuals occurring in the infralittoral and migrating to the intertidal zone throughout their ontogeny. Outcomes shown in the present study help improve the knowledge on population ecology of sandy beaches because they relate the distribution of a macrofauna species to environmental factors and mainly due to the fact that sampling covers also the infralittoral zone, since its distribution is not exclusive to the intertidal zone

Praias arenosas são caracterizadas por uma abundante macrofauna, composta por poliquetas, moluscos e crustáceos. Dentre os moluscos, os gastrópodes constituem um dos grupos mais conspícuos. Entretanto, as informações sobre esse grupo em praias são escassas e se referem principalmente à ocorrência em comunidades. O neogastropoda Olivella minuta é comum e abundante em praias do Litoral Norte de São Paulo. Porém, há importantes lacunas no conhecimento quanto à distribuição desta espécie. Diante desse cenário, o presente estudo visou analisar a distribuição espaço-temporal de Olivella minuta na praia de Barequeçaba, bem como os fatores ambientais relacionados a essa distribuição. Para análise da distribuição espacial de O. minuta ao longo do entre-marés da praia, amostras foram obtidas em outubro de 2009, a partir de doze estações perpendiculares à linha da água, compostas por três transectos com seis níveis cada. Os fatores abióticos (características do sedimento) e bióticos (descritores da macrofauna) que compõem cada estação também foram amostrados e relacionados com a distribuição da espécie. Os resultados revelaram que os indivíduos ocorreram em maior densidade na porção sul da praia, e nos ambientes mais úmidos, próximos a linha da água. O carbonato de cálcio e a matéria orgânica foram os fatores mais determinantes, contrastando com a hipótese de que há influência tanto dos fatores abióticos quanto dos bióticos em tal distribuição. Para análise de distribuição temporal de Olivella minuta no eixo vertical da praia, amostras foram obtidas mensalmente no entremarés, a partir de cinco transectos aleatórios estabelecidos perpendicularmente à linha da água, com nove unidades amostrais. Além disso, amostras foram obtidas trimestralmente, no entremarés e infralitoral, a partir de cinco transectos aleatórios, compostos por nove e seis níveis amostrais, respectivamente. Os resultados revelaram um padrão de distribuição da espécie no entremarés ao longo do tempo, e confirmaram a hipótese de que há uma distribuição de O. minuta de acordo com o tamanho do indivíduos no eixo vertical da praia, com indivíduos menores ocorrendo apenas no infralitoral e migrando para o entremarés ao longo de sua ontogenia. Os avanços apresentados no presente estudo contribuem para o conhecimento sobre a ecologia de populações de praias arenosas, ao relacionar a distribuição de uma espécie da macrofauna com os fatores ambientais, e principalmente ao abranger o infralitoral nas amostragens, por tratar da distribuição de uma espécie cuja distribuição não é exclusiva do entremarés / Sandy beaches have typically abundant macrofauna, comprised of polychaetes, mollusks, and crustaceans. Among mollusks, gastropods comprise one of the most conspicuous groups. Nevertheless, data on this group for beaches are scarce and refer mainly to their occurrence in communities. The neogastropoda Olivella minuta is common and abundant on beaches along the Northern Coast of São Paulo. However, there are important gaps in the knowledge regarding the distribution of this species. Based on this scenario, the present study aims at analyzing the distribution of Olivella minuta in space and over time on Barequeçaba Beach, as well as the related environmental factors. To analyze the distribution of Olivella minuta along the intertidal zone of the beach, samples were obtained in October 2009 from twelve stations perpendicular to the waterline, comprised of three transects with six levels each. Abiotic (sediment characteristics) and biotic (macrofauna descriptors) factors that comprise each station were also sampled and linked to distribution. Results showed that there was higher density of individuals in the southern part of the beach, and in more humid environments, closer to the waterline. Calcium carbonate and organic matter were the most determining factors in the species\' distribution, as opposed to the hypothesis that both abiotic and biotic factors were influencing factors. To analyze the distribution of Olivella minuta over time in the vertical axis of the beach, samples were collected monthly in the intertidal zone, from five random transects set out perpendicularly to the waterline with nine sampling units. In addition, samples were also obtained quarterly with five random transects comprised of nine and six sampling levels in the intertidal zone and in the infralittoral zone, respectively. Results showed a distribution pattern for the species in the intertidal zone over time and confirm the hypothesis that O. minuta is distributed along the vertical axis of the beach according to the size of individuals, with smaller individuals occurring in the infralittoral and migrating to the intertidal zone throughout their ontogeny. Outcomes shown in the present study help improve the knowledge on population ecology of sandy beaches because they relate the distribution of a macrofauna species to environmental factors and mainly due to the fact that sampling covers also the infralittoral zone, since its distribution is not exclusive to the intertidal zone

O objetivo deste trabalho foi analisar a distribuição espaço-temporal de um representante da macrofauna de praias arenosas protegidas. As abordagens em diferentes escalas (mesoescala, microescala e escala temporal) foram empregadas. O gastrópode Olivella minuta, abundante na região entremarés da Baía do Araçá, foi utilizado para essas análises. Para o estudo em mesoescala, 16 estações foram demarcadas na região entremarés (julho/2009) e, em cada uma, foram coletadas 8 amostras biológicas e 3 de sedimento. Alguns fatores abióticos (carbonato de cálcio, matéria orgânica e coeficiente de seleção) influenciaram negativamente a abundância do gastrópode, enquanto relações entre O. minuta e as demais espécies da macrofauna não foram evidentes. Em microescala, em poças de maré (metros) e em \"ripple marks\" (centímetros) verificou-se que em escala de centímetros, o gastrópode foi mais abundante em locais com maior conteúdo de água no sedimento, enquanto em escala de metros a abundância não diferiu dentro e fora das poças. Em escala temporal, foram observadas flutuações mensais da densidade da população de O. minuta, com diminuição/ausência de indivíduos entre fevereiro e março, o que sugere a ocorrência de migrações e mortalidade. O presente trabalho mostrou que a distribuição desse gastrópode é influenciada por diferentes fatores que atuam em diferentes escalas. / The objective of this study was to analyze the temporal and spatial distribution of one of the species representative of the macrofauna of sheltered sandy beaches. Measurements using different scales (mesoscale, microscale and time scale) were utilized. The gastropod Olivella minuta, which is abundant in the intertidal region of Baía do Araçá, was used for these analyses. For the mesoscale study, 16 stations were determined within the intertidal region (July/2009) and, in each station, 8 biological samples and 3 samples of sediment were collected. Some abiotic factors (calcium carbonate, organic matter and selection coefficient) had a negative influence on the abundance of the gastropod, while relationship between the O. minuta and other species of the macrofauna were not evident. In a microscale study of tidal ponds (meters) and ripple marks (centimeters), it was observed that, in a centimeter scale, the gastropod was more abundant in places where there was more water in the sediment, whereas in a meter scale the abundance didn\'t vary in or out of the ponds. In a temporal scale, monthly fluctuations of the O. minuta population\'s density were observed, with reduction/absence of individuals between February and March, which suggests that migration and mortality occurred. This study showed that the distribution of O. minuta is influenced by different factors which act in different scales.

These studies compare neurotransmitter localization and the behavioral functions of homologous neurons in nudibranch molluscs to determine the types of changes that might underlie the evolution of species-specific behaviors. Serotonin (5-HT) immunohistochemistry in eleven nudibranch species indicated that certain groups of 5 HT-immunoreactive neurons, such as the Cerebral Serotonergic Posterior (CeSP) cluster, are present in all species. However, the locations and numbers of many other 5 HT-immunoreactive neurons were variable. Thus, particular parts of the serotonergic system have changed during the evolution of nudibranchs. To test whether the functions of homologous neurons are phylogenetically variable, comparisons were made in species with divergent behaviors. In Tritonia diomedea, which crawls and also swims via dorsal-ventral body flexions, the CeSP cluster includes the Dorsal Swim Interneurons (DSIs). It was previously shown that the DSIs are members of the swim central pattern generator (CPG); they are rhythmically active during swimming and, along with their neurotransmitter 5-HT, are necessary and sufficient for swimming. It was also known that the DSIs excite efferent neurons used in crawling. DSI homologues, the CeSP-A neurons, were identified in six species that do not exhibit dorsal-ventral swimming. Many physiological characteristics, including excitation of putative crawling neurons were conserved, but the CeSP A neurons were not rhythmically active in any of the six species. In the lateral flexion swimmer, Melibe leonina, the CeSP-A neurons and 5-HT, were sufficient, but not necessary, for swimming. Thus, homologous neurons, and their neurotransmitter, have functionally diverged in species with different behaviors. Homologous neurons in species with similar behaviors also exhibited functional divergence. Like Melibe, Dendronotus iris is a lateral flexion swimmer. Swim interneuron 1 (Si1) is in the Melibe swim CPG. However, its putative homologue in Dendronotus, the Cerebral Posterior ipsilateral Pedal (CPiP) neuron, was not rhythmically active during swim-like motor patterns, but could initiate such a motor pattern. Together, these studies suggest that neurons have changed their functional relationships to neural circuits during the evolution of species-specific behaviors and have functionally diverged even in species that exhibit similar behaviors.

@font-face { font-family: "Arial"; }@font-face { font-family: "ＭＳ 明朝"; }@font-face { font-family: "Calibri"; }p.MsoNormal, li.MsoNormal, div.MsoNormal { margin: 0in 0in 0.0001pt; text-indent: 0.5in; line-height: 200%; font-size: 11pt; font-family: "Times New Roman"; }p.MsoBodyText, li.MsoBodyText, div.MsoBodyText { margin: 0in 0in 6pt; text-indent: 0.5in; line-height: 200%; font-size: 11pt; font-family: "Times New Roman"; }span.BodyTextChar { font-family: Calibri; }div.Section1 { page: Section1; } A 60 kDa monomeric protein isolated from the defensive purple ink secretion of the sea hare Aplysia californica has broad antimicrobial activity in tryptone peptone rich medium. This protein, which we call ‘escapin’, belongs to an L-amino acid oxidase family. The goals of my project were 1) to determine the products of escapin’s oxidation of its main substrate L-lysine, 2) to characterize the antimicrobial effects of escapin’s products, and 3) determine bactericidal mechanisms of action of these products. Escapin is a powerful bactericidal agent against several bacteria species including Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Vibrio harveyi. Escapin operates through a two-step process: 1) deamination of L-amino acids (especially L-lysine) by enzymatic activity to produce escapin intermediate products of L-lysine (EIP-K), hydrogen peroxide, and ammonia; and 2) EIP-K simultaneously reacts with hydrogen peroxide to generate escapin end products (EEP-K). EIP exists as an equilibrium mixture of the linear a-keto analogue of lysine and its cyclic forms, and the relative amount of the linear form increases with pH decreases. The powerful bactericidal effect of escapin requires the simultaneous presence of hydrogen peroxide and EIP-K in weak acidic conditions, which suggests that linear form of EIP-K with hydrogen peroxide is responsible for the bactericidal effect of escapin. Using E. coli MC4100 as a model, the mechanism of action of escapin was examined. Brief treatment with EIP-K + H2O2, but not EIP-K or H2O2 alone, causes irreversible DNA condensation with a time course similar to the bactericidal effect. A mutant strain resistant to EIP-K + H2O2 was isolated, and a single point mutation was found in the oxidative stress regulator gene (oxyR). Through a complementary assay, it was shown that wild type E. coli is conferred resistance to EIP-K + H2O2 by carrying mutated oxyR plasmid. Furthermore, in this bactericidal effect, heat or cold shock does not substitute for hydrogen peroxide induced oxidative stress. Thus, escapin’s powerful bactericidal effect may be through irreversible DNA condensation mediated through hydrogen peroxide generating an oxidative stress response, but the pathway mediating EIP-K’s synergistic effect is still unclear.

The Miocene Nullarbor Limestone is the most recent formation in the Cenozoic Eucla Group and was deposited in the Eucla Basin, southern Australia, at ~38°S paleolatitude during the early to middle Miocene. The rocks form the modern surface of the vast, karsted Nullarbor Plain. Older Eucla Group marine carbonates (Eocene-earliest Miocene) are cool-water in nature and dominated by bryozoans and echinoderms. The Nullarbor Limestone is subtropical in composition and rich in coralline algae (rhodoliths and articulated types), large and small benthic foraminifera and molluscs. Diverse zooxanthellate corals are also present but not numerous. Deposition is interpreted to have taken place in three main paleoenvironments: rhodolith gravels, seagrass banks, and open seafloors. The Southern Ocean extended inboard ~450 km from the shelf edge during Nullarbor Limestone deposition. Interpreted paleodepths ranged from the top to the base of the photic zone, implying a small slope over a wide shelf. The Miocene Eucla platform is therefore interpreted to have been epeiric in nature. Paleoenvironment distribution is explained using epeiric platform sedimentation patterns and comparisons with modern environments. Open seafloor environments, the deepest settings, are thought to have been below fair-weather wave base. Rhodolith gravels accumulated at intermediate depths, where waves frequently swept the seafloor. Seagrass banks developed in the shallowest waters farthest inboard, where wave energy had been largely dissipated. Diverse corals, large benthic foraminifera and micrite envelopes inboard and in the western part of the basin support the notion of paleotemperatures generally above 20°C, the upper limit of subtropical carbonate accumulation. Although deposition occurred during the Miocene Climatic Optimum, a simple overall temperature increase cannot completely account for the subtropical nature of these sediments at mid-latitudes. Tropical components decrease from west to east, implying a temperature gradient, probably due to the warm proto-Leeuwin Current. Thus, these subtropical carbonates were deposited at mid-latitudes and their presence did not simply reflect a change in global climate. / Thesis (Master, Geological Sciences & Geological Engineering) -- Queen's University, 2010-12-23 16:05:47.981

xv, 99 p. : ill. (some col.) A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number. / The trochid gastropod Chlorostoma (Tegula) funebralis is found in rocky intertidal habitats along the west coast of North America from Baja California to Vancouver Island. Size-frequency distributions of populations were analyzed along a latitudinal gradient from northern Oregon to Baja California. Populations in California and southern Oregon were dominated by individuals in the juvenile size classes (0.1g-2g). Along the Oregon coast, populations dominated by juveniles were correlated with coastline topography, with protected areas having large numbers of juveniles and exposed areas dominated by larger size classes. The largest size classes (>9g) were rarely present in southern populations. The seasonality of reproduction was investigated in a southern California population and an Oregon population to determine whether continuous reproduction in southern populations increases recruitment success over the year and decreases inter-annual variation in reproductive success. Constant recruitment may cause populations to have a large number of juveniles, the observed pattern in southern populations. Although individuals capable of reproduction were found year-round in both populations, the southern population experienced multiple spawning events over the year, while the northern population experienced only one such event. Constant recruitment may be a strategy to compensate for shorter life spans and smaller sizes of individuals in southern California. To investigate whether variations in predation rates on large adult C. funebralis affect the size structure of populations, the main predators and predation rates for different populations in Oregon were identified. All observed predation events were by the intertidal seastar Pisaster ochraceus . Predation pressure by P. ochraceus varied significantly with site and between sampling dates but did not remove enough C. funebralis from the adult population to have a significant effect on population size structure. To determine the connectivity between populations and the maximum dispersal potential, the mitochondrial gene COI was sequenced from individuals from nine populations ranging from southern California to northern Oregon. Although haplotype diversity was high, no genetic structure was found between populations. Rather than an indication of high dispersal potential and a panmictic species, the lack of isolation by distance may be a result of range expansion following the last glacial maximum. / Committee in charge: Patrick Phillips, Chairperson, Biology; Alan Shanks, Advisor, Biology; Craig Young, Member, Biology; Richard Emlet, Member, Biology; Jon Erlandson, Member, Anthropology; Gregory Retallack, Outside Member, Geological Sciences

Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-03-30T11:15:56Z No. of bitstreams: 1 patriciaaparecidadaniel.pdf: 3500302 bytes, checksum: 6ce77a584de445476bc8d26ebadf79e1 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-04-24T02:50:29Z (GMT) No. of bitstreams: 1 patriciaaparecidadaniel.pdf: 3500302 bytes, checksum: 6ce77a584de445476bc8d26ebadf79e1 (MD5) / Made available in DSpace on 2016-04-24T02:50:29Z (GMT). No. of bitstreams: 1 patriciaaparecidadaniel.pdf: 3500302 bytes, checksum: 6ce77a584de445476bc8d26ebadf79e1 (MD5) Previous issue date: 2013-02-27 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A maior parte dos estudos sobre reprodução de moluscos terrestres foi realizada com espécies de climas temperados. Esse conhecimento é de suma importância para se realizar estratégias de manejo de populações de moluscos, assim como controle de parasitos. O presente trabalho teve por objetivos comparar aspectos da biologia reprodutiva e do desenvolvimento do sistema reprodutor dos moluscos da espécie Leptinaria unilamellata mantidos isolados e pareados, além de averiguar se os moluscos adultos dessa espécie expostos a condições desfavoráveis de umidade, retêm os filhotes em seu trato reprodutivo. Para o estudo da reprodução, foram constituídos dois grupos experimentais. Um grupo formado por 30 indivíduos recém-nascidos, mantidos isolados em terrários individuais e outro formado por 30 indivíduos mantidos em pares. Em intervalos de quinze dias, foi medido o comprimento da concha dos moluscos. O aparecimento de filhotes no terrário foi o parâmetro utilizado para a constatação da maturidade sexual. Foram realizadas observações diárias para a verificação do número de eventos reprodutivos realizados, do número de filhotes por evento reprodutivo e intervalo entre eventos reprodutivos. Para a determinação do investimento reprodutivo dos moluscos mantidos isolados e pareados, após o nascimento dos filhotes, os moluscos parentais e respectiva prole foram pesados para o cálculo desse índice. Com relação ao crescimento da concha, observou-se que durante a fase jovem, os indivíduos pareados apresentaram um ritmo mais rápido com relação aos isolados. Após a maturidade sexual, a taxa de crescimento dos moluscos isolados e pareados passou a ser semelhante e tendeu a se estabilizar no decorrer do tempo. Os moluscos mantidos pareados alcançaram primeiro a maturidade sexual do que os mantidos isolados. Além disso, os indivíduos mantidos pareados apresentaram mais eventos reprodutivos e um maior número de filhotes ao decorrer do experimento em comparação aos mantidos isolados. Com relação à fecundidade, os moluscos mantidos isolados apresentaram uma média significativamente maior em relação aos mantidos pareados (F=16.3585; p<0,0010). No decorrer de todos os eventos reprodutivos, os indivíduos pareados apresentaram um investimento reprodutivo médio significativamente menor quando comparado ao IR encontrado para os indivíduos isolados (8,15% e 12,28% respectivamente) (ANOVA p=0;F=34.0539). Para o estudo do desenvolvimento do sistema reprodutor, 30 indivíduos mantidos isolados e 30 pareados (sendo 6 indivíduos destinados ao estudo de cada faixa etária) nas idades de 15, 45, 75, 90 e 105 dias foram destinados ao estudo histológico. Foi possível observar que não há diferenças na conformação do sistema reprodutor nas diferentes idades e entre os moluscos mantidos isolados e pareados. Observou-se a presença do ovotestis nos moluscos com idade de 15 dias apenas os moluscos pareados, o que pode indicar que essa glândula é formada mais tardiamente nos moluscos mantidos isolados. Para a caracterização do comportamento de retenção dos filhotes, foram constituídos dois grupos experimentais contendo cada 30 moluscos mantidos isolados. O grupo 1 foi mantido durante todo o experimento sob condições favoráveis de umidade, enquanto que na primeira fase do experimento o grupo 2 foi submetido a condições desfavoráveis de umidade. Foi possível averiguar que os moluscos expostos ao estresse hídrico são capazes de reter seus filhotes no oviduto, sendo que realizam a postura logo que as condições de umidade se tornam melhores. Observou-se também que os moluscos da espécie L. unilamellata, além de entrarem no estado metabólico de estivação também são capazes de formar epifragma vedando assim a abertura da concha, evitando a perda de água para o ambiente. / Most of the studies on snails reproduction were realized with species of temperate climate. This knowledge is important to development of management strategies of snails populations, so as to controlling parasites. The present work aimed to compare aspects of reproductive biology and development of reproductive system of Leptinaria unilamellata maintained isolated and grouped, besides to ascertain if this snail species when exposed to unfavorable humidity conditions retain its offspring in their reproductive tract. Two experimental groups were made to assess reproduction. One with 30newly hatched individuals, maintained isolated and other with 30 individuals in pairs. Every fifteen days, the Shell length was measured. To verify the sexual maturity it was observed the presence of juveniles in the terrariums. Daily observations were realized too verify the number of reproductive events, the number of individuals in each event and the interval between reproductive events. To determinate the reproductive investment of snails from both groups, after birth, the parental snails and its offspring were heighted to provide data in order to calculate this index. With regard to shell growth, it was observed that in juveniles maintained in pairs showed higher growth rates in comparison to isolated ones. After maturity, the growth rates of isolated and paired snails were alike, with a trend to establishment in the course of time. Paired snails reached sexual maturity before isolated. Moreover, paired individuals presented more reproductive events and a larger number of juveniles when compared to isolated snails. The fecundity of isolated snails presented a mean significantly higher in relation to paired (F=16.3585; p<0,0010). During the observation period paired individuals showed mean reproductive investment significantly lower when compared to isolated individuals (8,15% and 12,28% respectively) (ANOVA p=0;F=34.0539). To assess the development of reproductive system, 30 individuals maintained isolated and 30 paired (with 6 individuals separated to the study of each age) at the ages of 15, 45, 75, 90 and 105 days were utilized in histological study. It was observed that there is no difference in reproductive system in the different ages and among snails maintained isolated and paired. The ovotestis was observed in15 days only in paired snails, which can indicate that this gland is formed lately in isolates snails. To verify the behavior of retention of the offspring it were made two groups, each one with 30 isolated snails. The group 1 was maintained under favorable humidity conditions, while in the first phase of the assay the group 2 was submitted to unfavorable humidity conditions. It was observed that snails exposed to water stress are capable to retain its offspring in the oviduct, realizing oviposition as soon as the humidity conditions improve. It was observed that L. unilamellata, besides aestivation they also can produce an epiphragm that sealing the shell and avoiding the water loss to the environment.

Dans l'environnement, les organismes sont soumis à des stress de multiples natures (e.g., polluants et pathogènes/parasites). Dans ce contexte, le système immunitaire joue un rôle fondamental. La pression chimique exercée par les polluants peut impacter leur système immunitaire, affaiblir leur santé et les prédisposer à contracter des maladies infectieuses. En écotoxicologie, l'évaluation de marqueurs d'immunocompétence peut servir à diagnostiquer l'état de santé des organismes et mieux comprendre le danger immunotoxique des xénobiotiques. Lymnaea stagnalis est un gastéropode d'eau douce représentatif de nombreux milieux lentiques sur la planète. Des tests OCDE de reprotoxicité sont disponibles mais peu d'études se sont focalisées sur des paramètres immunotoxiques. Le premier axe de la thèse se porte sur la connaissance et le développement de méthodes pour évaluer l'immunocompétence de manière répétée à l'échelle individuelle chez L. stagnalis. Le deuxième axe évalue cette approche multibiomarqueurs dans différents contextes écotoxicologiques. Plusieurs populations (élevages vs terrain), temps d'expositions (3 vs 29 – 44 jours), concentrations d'exposition (environnementales vs non réalistes) et contaminants ont été évalués : des médicaments (les anti-cancéreux Etoposide et cyclophosphamide, l'anti-rejet de greffes cyclosporine A et l'antiinflammatoire diclofenac), l'insecticide deltaméthrine, le métal cadmium et des effluents de station d'épuration. Des comparaisons entre des traits de vie et des traits immunitaires ont été réalisées. La réflexion est bâtie sur les questionnements relatifs à (i) la sensibilité de l'approche, (ii) le temps de réponse des marqueurs, (iii) leur précocité physiologique, (iv) la transposition d'immunotoxicité de xénobiotiques entre le phylum des chordata et L. stagnalis et (vi) l'utilisation pratique de L. stagnalis (élevages, collecte en milieu naturel, calibration, reproduction) / In natural environments, animals encounter multiple stresses (e.g., pollutants and pathogens/ parasites). In this context, the immune system plays a pivotal role. Chemical insults from pollutants can jeopardize the immune system of these animals, weaken their health and make them vulnerable to contracting infectious diseases. In ecotoxicology, assessment of immunocompetence markers can be used to diagnose the health of organisms and better understand the immunotoxic hazard of xenobiotics. Lymnaea stagnalis is a freshwater gastropod representative of several lentic ecosystems on the planet. OECD reprotoxicity tests are available using this species, but too few studies have focused on immunotoxic parameters. The first part of this thesis covers the description, comprehension and development of the methods used to assess the immunocompetence at an individual scale and repeatedly within an experiment in L. stagnalis. The second part assesses this multibiomarker approach in several ecotoxicological contexts. Several populations (laboratory-bred vs collected in the field), time exposures (3 vs 29–44 days), concentrations (environmental vs unrealistic) and contaminants were evaluated : pharmaceuticals (the anti-cancer drugs etoposide and cyclophosphamide, the anti-xenograft rejection drug cyclosporine A, the anti-inflammatory drug diclofenac), the insecticide deltamethrin, the metal cadmium and wastewater treatment plant effluents. The general reasoning is built on questions relative to (i) the sensitivity of the approach, (ii) the rapidity of the response, (iii) their physiological precocity of alteration (immune vs life-history traits), (iv) the transposition of xenobiotic immunotoxicity between L. stagnalis and the Chordata phylum and (vi) the pragmatic use of L. stagnalis (breeding, collection in the environment, calibration and reproduction)