Les planaires sont des plathelminthes d'eau douce non parasitaires qui ont été intensément étudiés pour leurs capacités exceptionnelles de régénération. En 2014, Abnave et ses collaborateurs ont démontré la capacité de Dugesia japonica, une espèce de planaire, à résister aux bactéries pathogènes pour l’homme et pour d’autres organismes modèles. Grâce à l’utilisation de techniques transcriptomiques et de criblage par ARN interférence, l’implication du gène Morn-2 dans cette résistance aux bactéries a été démontrée et l’étude de Morn-2 dans les macrophages humains a permis d’identifier son rôle dans la LAP (LC3 Associated Phagocytosis) autophagie ; Les planaires peuvent donc servir de modèle pour la découverte d’autres mécanismes de résistance conservés chez l’homme. Cependant, la réponse immunitaire des planaires a jusqu’ici été très peu explorée. Ce travail a été entrepris en vue d’identifier et de caractériser les mécanismes mis en jeu par ce modèle pour répondre efficacement aux bactéries. Dans une première partie de ce travail, il est démontré que les planaires possèdent une mémoire immunitaire innée spécifique à Staphylococcus aureus. Ensuite l’influence du rythme circadien sur la réponse antibactérienne des planaires a été examinée. Pour finir, l’intérêt s’est porté sur les mécanismes de reconnaissance et d’activation de la réponse antibactérienne chez les planaires. En dépit de l’absence de récepteurs Toll Like Receptor (TLR) chez les planaires, il est montré que des gènes homologues aux gènes de la voie de signalisation TLR des mammifères sont présents chez ces derniers. / Planarians are freshwater flatworms that have been intensively studied for their regenerative capacities. These non-parasitic Platyhelminthes are in their natural aquatic environment perpetually in contact with dense and diverse microbial population. Planarians have recently attracted broad attention owing to the discovery of innate immune regulators conserved in humans but absent in other classical model organisms. Notably, Abnave and collaborators highlighted the ability of Dugesia japonica and Schmidtea mediterranea of resisting to pathogenic bacteria by mean of Morn2-dependent LC3-associated phagocytosis. However, critical questions remain about mechanisms conferring a resistance of planarians to pathogenic bacteria as well as their mode of perception of PAMPs. In this work we explored different components of planarians immune system. First, we demonstrated the existence in planarians of an innate immune memory that is specific to Staphylococcus aureus. Second, we investigated the role of the circadian machinery in the anti-bacterial response. Surprisingly, classical Toll Like receptors (TLRs) are absent in planarians despite their wide conservation in the animal kingdom. We found genes in planarians showing similarities with mammalian TLR signalling components. Moreover, we report the landscape of TIR-domain containing proteins in planarians and discuss their function and evolution with regard to known TLR-signalling components.

Made available in DSpace on 2015-03-05T16:19:36Z (GMT). No. of bitstreams: 0 Previous issue date: 29 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A influência de fatores ecológicos na ocorrência de planárias terrestres é pouco conhecida. Estudos da estrutura de comunidades de planárias demonstram que estes organismos realizam seleção de habitat, apresentando baixa diversidade em habitats perturbados. O presente estudo objetiva testar se a ocorrência de planárias terrestres é influenciada por características do microhabitat, tais como características estruturais do ambiente, características edáficas e disponibilidade de presas. O estudo foi desenvolvido em duas áreas de Floresta Ombrófila Mista, na Floresta Nacional de São Francisco de Paula (FLONA-SFP), no Sul do Brasil. Em cada área, foi demarcada uma extensão de meio hectare, subdividido em quadrantes de 10m2. Em 100 parcelas distribuídas aleatoriamente, foram registradas a ocorrência e abundância de tricladidos, além de variáveis ecológicas. Foram analisadas seis características estruturais do ambiente (número de rochas, número e tamanho dos troncos e galhos caídos, altura do folhiço, densidade de a / In general, the influence of ecological factors on the occurrence of land planarians is poorly known. Studies on flatworm community structure verified that these organisms show habitat selection, exhibiting low diversity in disturbed habitats. The aim of this study is to test if the occurrence of land planarians are influenced by microhabitat traits, such as habitat structural traits, soil features and prey availability. The study was developed in two Araucaria Forest areas in the São Francisco de Paula National Forest (FLONA-SFP), southern Brazil. In each area, a grid of 0.5 hectares, subdivided in 10m2 plots, was established. In 100 randomly selected plots, the occurrence and abundance of each land planarian species were recorded. For each plot, we also recorded information on six habitat structural traits (number of stones, number and size of fallen trunks, shrub density, litter height, canopy openness), 21 soils features (physical and chemical variables), and 15 prey availability traits (total abundance o

Este trabalho consiste em uma caracterização morfológica das espécies-tipo da maioria dos gêneros que compõem a subfamília Geoplaninae, e quatro espécies destinadas a servir como grupos externos (Pelmatoplanini, Anzoplanini, Caenoplanini, Bipaliinae). A estudo morfológico das espécies resultou em 69 caracteres morfológicos que foram inseridos em uma matriz de dados e preparados para análise filogenética. Quinze espécies adicionais de outros gêneros de Geoplaninae também foram incluídos na análise. Os resultados corroboram o monofiletismo da subfamília Geoplaninae. De acordo com a hipótese de Meixner, o clado formado pelos gêneros Enterosyringa e Xerapoa, que compartilha características morfológicas com espécies do grupo externo, é o grupo de irmãos de todas as demais espécies de Geoplaninae. Descobrimos que as características anatômicas do aparelho copulador, como a presença e o tipo de papila peniana mostraram possuir muitas reversões e não se mostraram filogeneticamente informativas. Caracteres do sistema muscular podem ser usados de forma mais efetiva para a definição de grupos taxonômicos dentro do Geoplaninae e como indicadores de suas relações evolutivas. Nenhum dos aspectos diagnóstico atuais de da Geoplaninae correspondeu a caracteres autopomórficos em nossa análise. Nossos resultados sugerem que vários gêneros de Geoplaninae representam grupos não naturais, i.e., Geoplana e Notogynaphallia, com alguns caracteres diagnósticos sendo homoplásicos. / This work consists of a morphological characterization of the type species of most of the genera that compose Geoplaninae, and four species intended to serve as outgroups (Pelmatoplanini, Anzoplanini, Caenoplanini, Bipaliinae). The morphological study of the species resulted in 69 morphological characters that were entered into a data matrix and prepared for phylogenetic analysis. Fifteen additional species from other Geoplaninae genera were also included in the analysis. The results corroborate the monophyletic status of the subfamily Geoplaninae. According with Meixner\'s hypothesis, the clade formed by Enterosyringa and Xerapoa species, sharing morphological characteristics with outgroup species, is the sister group of all other Geoplaninae species. We found that anatomical features of the copulatory apparatus, such as the presence and type of penis papilla showed many reversions and were not phylogenetically informative. Characters of the muscular system can be used much better for defining taxonomic groups within the Geoplaninae and as indicators of their evolutionary relationships. None of the present diagnostic features of the Geoplaninae formed autapomorphic characters in our analysis. Our results suggest that several genera of Geoplaninae represent unnatural groups, viz., Geoplana and Notogynaphallia, with some diagnostic characters being homoplasic.

Este trabalho consiste em uma caracterização morfológica das espécies-tipo da maioria dos gêneros que compõem a subfamília Geoplaninae, e quatro espécies destinadas a servir como grupos externos (Pelmatoplanini, Anzoplanini, Caenoplanini, Bipaliinae). A estudo morfológico das espécies resultou em 69 caracteres morfológicos que foram inseridos em uma matriz de dados e preparados para análise filogenética. Quinze espécies adicionais de outros gêneros de Geoplaninae também foram incluídos na análise. Os resultados corroboram o monofiletismo da subfamília Geoplaninae. De acordo com a hipótese de Meixner, o clado formado pelos gêneros Enterosyringa e Xerapoa, que compartilha características morfológicas com espécies do grupo externo, é o grupo de irmãos de todas as demais espécies de Geoplaninae. Descobrimos que as características anatômicas do aparelho copulador, como a presença e o tipo de papila peniana mostraram possuir muitas reversões e não se mostraram filogeneticamente informativas. Caracteres do sistema muscular podem ser usados de forma mais efetiva para a definição de grupos taxonômicos dentro do Geoplaninae e como indicadores de suas relações evolutivas. Nenhum dos aspectos diagnóstico atuais de da Geoplaninae correspondeu a caracteres autopomórficos em nossa análise. Nossos resultados sugerem que vários gêneros de Geoplaninae representam grupos não naturais, i.e., Geoplana e Notogynaphallia, com alguns caracteres diagnósticos sendo homoplásicos. / This work consists of a morphological characterization of the type species of most of the genera that compose Geoplaninae, and four species intended to serve as outgroups (Pelmatoplanini, Anzoplanini, Caenoplanini, Bipaliinae). The morphological study of the species resulted in 69 morphological characters that were entered into a data matrix and prepared for phylogenetic analysis. Fifteen additional species from other Geoplaninae genera were also included in the analysis. The results corroborate the monophyletic status of the subfamily Geoplaninae. According with Meixner\'s hypothesis, the clade formed by Enterosyringa and Xerapoa species, sharing morphological characteristics with outgroup species, is the sister group of all other Geoplaninae species. We found that anatomical features of the copulatory apparatus, such as the presence and type of penis papilla showed many reversions and were not phylogenetically informative. Characters of the muscular system can be used much better for defining taxonomic groups within the Geoplaninae and as indicators of their evolutionary relationships. None of the present diagnostic features of the Geoplaninae formed autapomorphic characters in our analysis. Our results suggest that several genera of Geoplaninae represent unnatural groups, viz., Geoplana and Notogynaphallia, with some diagnostic characters being homoplasic.

The freshwater planarian Schmidtea mediterranea has been used in research for over 100 years, and is an emerging stem cell model. Exteriorly, planarians are covered in mucous secretions of unknown composition. While the planarian genome has been sequenced, it remains mostly unannotated. The goal my master’s research was to annotate the planarian proteome and mucous sub-proteome. Using a proteogenomics approach, I elucidated the proteome and mucous subproteome via mass spectrometry together with an in silico translated transcript database. I identified 1604 proteins, which were annotated using the Swiss-Prot BLAST algorithm and Gene Ontology analysis. The S. mediterranea proteome is highly similar to that predicted for the trematode Schistosoma mansoni associated with schistosomiasis. Remarkably, orthologs of 119 planarian mucous proteins are present in human mucosal secretions and tear fluid. I suggest planarians have potential to be a model system for parasitic worms and diseases underlined by mucous aberrancies.

The freshwater planarian Schmidtea mediterranea has been used in research for over 100 years, and is an emerging stem cell model. Exteriorly, planarians are covered in mucous secretions of unknown composition. While the planarian genome has been sequenced, it remains mostly unannotated. The goal my master’s research was to annotate the planarian proteome and mucous sub-proteome. Using a proteogenomics approach, I elucidated the proteome and mucous subproteome via mass spectrometry together with an in silico translated transcript database. I identified 1604 proteins, which were annotated using the Swiss-Prot BLAST algorithm and Gene Ontology analysis. The S. mediterranea proteome is highly similar to that predicted for the trematode Schistosoma mansoni associated with schistosomiasis. Remarkably, orthologs of 119 planarian mucous proteins are present in human mucosal secretions and tear fluid. I suggest planarians have potential to be a model system for parasitic worms and diseases underlined by mucous aberrancies.

No description available.

O Estado do Tocantins está se tornando um dos principais polos de cultivo agrícola do Brasil e a disponibilidade de recursos hídricos têm fortalecido a produção agrícola no Estado. As áreas de monocultura estendem-se principalmente ao longo da bacia hidrográfica Araguaia e Tocantins, sendo estes os dois principais sistemas de drenagem. Para obtenção de elevadas produtividades, os cultivos agrícolas são altamente dependentes do uso de pesticidas. Adicionalmente, os pesticidas agrícolas podem chegar aos ecossistemas aquáticos através da lixiviação e deriva após a aplicação e também através da adsorção a materiais biológicos e às partículas de argila do solo que são carregados para sistemas aquáticos pelos processos de erosão. Consequentemente, o ecossistema aquático pode ser afetado, devido ao efeito tóxico destes pesticidas para espécies aquáticas de diferentes níveis tróficos. Como resultado de uma pesquisa de campo em várias áreas de cultivo no Estado do Tocantins, verificou-se que o inseticida tiametoxam (TMX), o fungicida ciproconazol (CPZ) e o herbicida Paraquat (PQ) estão entre os principais pesticidas utilizados em diversas culturas e em diferentes áreas de cultivo. O objetivo deste estudo foi avaliar a toxicidade de TMX, CPZ e PQ para invertebrados de água doce, de modo a contribuir para análise de risco ecológico de pesticidas agrícolas no ecossistema da bacia hidrográfica Araguaia-Tocantins. Como a informação sobre a toxicidade letal e sub-letal de diferentes compostos, particularmente para espécies aquáticas ecologicamente relevantes, é crucial para a avaliação dos riscos de pesticidas em ecossistemas aquáticos, foram realizados ensaios ecotoxicológicos, utilizando ensaios laboratoriais com dois invertebrados de água doce, o díptero Chironomus riparius e a planária Dugesia tigrina. Estudos preliminares revelaram que TMX não é tóxico para D. tigrina em concentrações ambientalmente relevantes, logo a toxicidade deste pesticida foi avaliada apenas sobre C. riparius (sobrevivência, crescimento, emergência e avaliação de respostas bioquímicas). Na avaliação da toxicidade de CPZ, os parâmetros avaliados em C. riparius incluem sobrevivência, crescimento e emergência, enquanto que em D. tigrina foram avaliados sobrevivência, regeneração e respostas comportamentais (locomoção e alimentação). Para avaliação da toxicidade de PQ, ensaios crônicos foram conduzidos com C. riparius (avaliação de crescimento, emergência e peso de mosquitos adultos) e D. tigrina (avaliação de regeneração, locomoção e alimentação). Os resultados evidenciaram que TMX é altamente tóxico para C. riparius, uma vez que concentrações ambientalmente relevantes afetam não só o desenvolvimento do organismo, mas também a sobrevivência. O fungicida CPZ é moderadamente tóxico para C. riparius (atraso no tempo à emergência) e D. tigrina (decréscimo da atividade locomotora, atividade alimentar e capacidade de regeneração). O herbicida PQ também provocou atraso no tempo à emergência, além de diminuição do tamanho dos adultos de C. riparius, bem como redução na atividade locomotora, atividade alimentar e capacidade de regeneração de D. tigrina. Este estudo acrescenta dados ecotoxicológicos sobre os efeitos de TMX, CPZ e PQ sobre invertebrados de água doce e sugere que, em longo prazo, estes pesticidas podem potencialmente perturbar cadeias alimentares e estrutura da comunidade nos ecossistemas de água doce. A aplicação destes pesticidas em particular na bacia hidrográfica Araguaia-Tocantins deve ser cuidadosamente monitorada nas áreas agrícolas de modo evitar impactos sobre os ecossistemas aquáticos. / The State of Tocantins is becoming one of the main agricultural centers in Brazil, and the availability of water resources have strengthened agricultural production in the state. Monoculture areas extend mainly along the Araguaia and Tocantins watersheds, which are the two main drainage systems. To achieve high productivity, agricultural crops are highly dependent of pesticide use. As such, agricultural pesticides may reach the aquatic ecosystems through leaching and drift after application, also through the adsorption to biological materials and soil clay particles that are carried to aquatic system by erosion. Consequently, the aquatic ecosystem may be affected due to the toxic effect of these pesticides to aquatic species of different trophic levels. As a result of a field survey of several areas of cultivation in the State of Tocantins, it was found that the insecticide thiamethoxam (TMX), the fungicide cyproconazole (CPZ) and the herbicide paraquat (PQ) are the main pesticides used in many crops, in different areas of cultivation. The aim of this study was to evaluate the toxicity of TMX, CPZ and PQ for freshwater invertebrates, in order to contribute to ecological risk assessment of agricultural pesticides in the ecosystem of the Araguaia-Tocantins watershed. Since information on the lethal and sub-lethal toxicity of the different compounds, particularly for ecologically relevant aquatic species, is crucial for risk assessment of pesticide in aquatic ecosystems, ecotoxicological tests were carried using laboratory tests with two freshwater invertebrates, the dipteran Chironomus riparius and the planarian Dugesia tigrina. Preliminary studies revealed that environmentally relevant concentrations of TMX is did not induced toxicity to D. tigrina and thus, effects of this insecticide were evaluated only using C. riparius (survival, growth, emergence and evaluation of biochemical responses). In the evaluation of CPZ toxicity, the endpoints evaluated in C. riparius included survival, growth and emergence, while in D. tigrina effects were evaluated in terms of survival, regeneration and behavioral responses (locomotion and feeding). For the assessment of PQ toxicity, chronic tests were conducted with C. riparius (growth, emergence and adult weight) and D. tigrina (regeneration, locomotion, and feeding). Our results showed that TMX is highly toxic to C. riparius, since environmentally relevant concentrations affects not only the development rates, but also survival. The CPZ fungicide is moderately toxic to C. riparius (delayed emergence time) and D. tigrina (decreased locomotor activity, feeding activity and delayed regeneration). The herbicide PQ also caused a delay in emergence time and decrease in body weight of C. riparius imagos, as well as reduction in locomotor activity, feeding activity and regeneration of D. tigrina. This study adds ecotoxicological data on the effects of TMX, CPZ and PQ to freshwater invertebrates and suggests that in the long term, these pesticides can potentially disrupt food chains and community structure in freshwater ecosystems. The application of these pesticides namely in the Araguaia-Tocantins watershed should thus be closely monitored in agricultural areas in order to avoid impacts on aquatic ecosystems.

No description available.

Les interactions hôte-pathogène sont un jeu vaste et complexe entre agent pathogène et hôtepour la victoire de la bataille de la pathogenèse. Plusieurs organismes modèles sont étudiéspour illustrer les mécanismes impliqués dans ces interactions. Dans ma thèse, j'ai utilisé lesplanaires comme un organisme modèle pour explorer les interactions hôte-pathogène. Comme les différents organismes modèles peuvent mettre enévidence les différentes caractéristiques de l'immunité, j'ai décidé de tirer avantage del'absence de connaissances sur l'immunité des planaires en explorant l'inexplorée. Dans monprojet, j'ai infecté les planaires avec 16 bactéries pathogènes : les planaires y sont très résistantes. Pour en explorer lemécanisme j'ai effectué un profilage du transcriptome à partir deplanaires infectées, suivie par un criblage par ARN interférence des gènes up-régulés. J'aidécouvert les gènes qui régissent la résistance antibactérienne dans les planaires, et de façonintéressante, le criblage a permis de mettre en évidence un gène, MORN2, dont la fonctionimmunologique était complètement inconnue. L'induction et l'extinction de l'expression de MORN2dans les macrophages ont révélé que MORN2 contrôle l'internalisation, la réplication et letrafic des bactéries à l'intérieur de la cellule. Dans mon étude, j'ai démontré que MORN2 estun composant de la phagocytose associée à LC3 et qu'il peut surmonter le blocage de lafusion phagolysosomale imposée par les bactéries pathogènes. Ainsi ma thèse met en avantl'importance d'utiliser des organismes modèles inhabituels afin de dévoiler des mécanismesinexplorées et des molécules impliquées dans les interactions hôte-pathogène. / Host-pathogen interaction is a vast and complex interplay between pathogen and hostto conquer the battle of pathogenesis. Several model organisms are being studied to illustratethe mechanisms involved in these interactions. In my thesis I have used planarians as a modelorganism to explore host-pathogen interactions. As different model organismscan highlight different features of immunity I decided to take advantage of lack of knowledgeabout planarian immunity and get benefits from exploring unexplored. In my project I haveinfected planarians with 16 pathogenic bacteria and I found that in contrary to othercommonly used model organisms such as Drosophila, C. elegans and zebrafish the planariansare highly resistant to bacterial infections. To explore the mechanism behind this resistance Iperformed infection induced transcriptome profiling followed by RNA interference screeningof up-regulated gens. I discovered genes governing antibacterial resistance in planarians andinterestingly the screening highlighted a gene MORN2 of which the immunological functionwas completely unknown. The human ortholog of MORN2 is then further assessed for itsantimicrobial function. Induced expression and down regulation of MORN2 in macrophagesrevealed that MORN2 controls uptake, replication and trafficking of bacteria inside the cell.In my study I demonstrated that MORN2 is a component of LC3-associated phagocytosis andit can overcome phagosome maturation blockage imposed by pathogenic bacteria. Thus mythesis propounds the importance of using unusual model organisms to unveil unexploredmechanisms and molecules involved in host-pathogen interactions.