Oxidative stress is caused by an imbalance between high production of reactive oxygen species and ability of organism to detoxify them or counteract their effects. The chromosomal ends telomeres - are specialized nucleoprotein structures protecting chromosome ends from DNA damage. Telomeres of Drosophila melanogaster are arrays of specific non-long terminal repeated (LTR) retrotransposons HeT-A, TART and TAHRE. This thesis evaluates effects of exposure of paraquat, which is a strong oxidative stress inducer, on telomere length and transcription activity in Drosophila.

Le moment, la qualité et la quantité de sommeil dépendent de l'interaction fine entre l'horloge circadienne et la machinerie homéostatique (Borbely A. et al., 1982, Daan S. et al., 1984, Borbely et Achermann, 1999). Au cours des dernières années, l'utilisation de divers organismes modèles a fourni de nouvelles perspectives sur les mécanismes neuronaux et moléculaires de la régulation du sommeil (Miyazaki S. et al., 2017). Cependant, les bases moléculaires de l'homéostasie du sommeil et les circuits neuronaux sous-jacents à son interaction avec le réseau circadien n'ont pas été établis en détail.Dans ce travail de thèse, j'ai utilisé la mouche Drosophile melanogaster comme système modèle pour étudier la fonction d'un sous-ensemble de neurones d'horloge, les DN1ps, dans la mise en place du sommeil. Des études antérieures ont suggéré un rôle de ces neurones circadiens dans la régulation du sommeil (Kunst et al., 2014, Guo et al 2016, Lamaze et al., 2017, Guo et al., 2017). J’ai ainsi démontré que les cellules d'horloge DN1ps DH31 (+) CRY (+) sont impliquées dans la suppression du sommeil. Par ailleurs, j’ai mis en évidence un circuit en aval des DN1ps, qui comprend le groupe dopaminergique postérieur apparié latéral 1 (PPL1) et les neurones dorsaux en forme d’éventail (dFSB), un centre homéostatique récemment décrit pour la régulation du sommeil chez la drosophile (Donlea JM et al., 2011, Liu S. et al., 2012, Ueno et al., 2012, Donlea JM et al., 2014, Pimentel et al., 2016, Qian et al., 2017, Donlea JM. et al., 2018). Nos résultats indiquent que la suppression du sommeil nocturne nécessite la signalisation DH31-R2 dans une sous-population des neurones dopaminergiques PPL1, qui projette au dFSB. Fait intéressant, la perte de sommeil de jour et de nuit médiée par les DN1ps dépend de l'inhibition du dFSB. Néanmoins, nous suggérons que les neurones DN1ps CRY (-) favoriseraient le sommeil, en concordance avec d'autres travaux (Guo et al., 2016; Guo et al., 2017).Ces résultats fournissent de nouvelles données sur le lien entre l'horloge circadienne et l'homéostasie du sommeil, impliqué dans la régulation du comportement sommeil-éveil chez Drosophile melanogaster. / The timing, quality and quantity of sleep depend on the fine interaction between circadian clock and homeostatic machinery (Borbely A. et al., 1982; Daan S. et al., 1984; Borbely and Achermann, 1999). In the recent years, the employment of various model organisms has provided new insights into the neuronal and molecular mechanisms of sleep regulation (Miyazaki S. et al., 2017). However, the molecular basis of the sleep homeostat and the neuronal circuitry underlying its interaction with the circadian network haven’t been established in details.In this work, I use the fruit fly Drosophila melanogaster as a model system to investigate the sleep function of a subset of clock neurons, the DN1ps. Previous studies have already suggested a sleep-regulating role for these circadian neurons (Kunst et al. 2014, Guo et al. 2016; Lamaze et al., 2017; Guo et al. 2017). Here, we report the DH31-positive CRY-positive DN1ps as sleep suppressing clock cells. Furthermore, we identify a sleep-relevant circuit downstream of the DN1ps which includes the paired posterior lateral 1 (PPL1) dopaminergic cluster and the dorsal Fan-shaped body projecting (dFSB) neurons, a recently described homeostatic center for sleep regulation in Drosophila (Donlea JM. et al., 2011; Liu S. et al., 2012; Ueno et al., 2012; Donlea JM. et al., 2014; Pimentel et al., 2016; Qian et al., 2017; Donlea JM. et al., 2018). Our results indicate that the night-time sleep suppression requires DH31-R2 signaling in the PPL1-to-dFSB dopaminergic neurons. Interestingly, both day and night-time DN1ps-mediated sleep loss rely on the inhibition of the dFSB. Nevertheless, we suggest the CRY-negative DN1ps as sleep promoting clock neurons, in concordance with other works (Guo et al. 2016; Guo et al. 2017).These findings provide a novel link between circadian clock and sleep homeostat, in the regulation of sleep-wake behavior in Drosophila melanogaster.

Je me suis intéressé au système de défense anti-viral majeur de Drosophila melanogaster qui est la voie du RNA silencing (siRNA). A ce jour, le seul senseur d’acide nucléique viral et activateur de la voie siRNA est Dicer-2. Ainsi, le travail que j’ai effectué́ a permis d’apporter de nouvelles informations concernant la détection des ARNs viraux par Dicer-2. L’utilisation de méthodes de séquençage à haut débit (HTS) des petits ARNs dans des cellules S2 infectées par le Drosophila C Virus (DCV) à des temps précoces m’a permis de proposer un point d’entrée précis et interne de Dicer-2 sur l’ARN double brin de ce dicistrovirus. La validation de ce point faible dans la défense du virus a été effectuée en réalisant un HTS des petits ARNs dans des mouches de différents génotypes infectées avec DCV. J’ai ensuite caractérisé plus en profondeur cette région du génome virale en déterminant tout d’abord sa structure 2D puis sa sensibilité à des clivages médiés par des extraits embryonnaires de mouches. Finalement, l’utilisation de différents variants de Dicer-2 présentant des mutations du domaine DRA m’a permis de proposer un nouveau mécanisme de fonctionnement de cette protéine. / My Ph.D revolved around the study of the major antiviral defense system of Drosophila melanogaster: the siRNA pathway. To date, the only viral nucleic acid sensor and siRNA pathway activator in drosophila is Dicer-2. Thus, the work I have done has provided new information regarding the detection of viral RNAs by Dicer-2. The use of high throughput sequencing (HTS) methods of small RNAs in S2 cells infected with Drosophila C Virus (DCV) at early time points has allowed me to propose a precise and internal entry point for Dicer-2 on the double-stranded RNA of this dicistrovirus. The validation of this weak point in the defence of the virus was carried out by performing an HTS of small RNAs in flies of different genotypes infected with DCV. I then characterized this region of the viral genome in more depth by first determining its 2D structure and then its sensitivity to cleavages mediated by embryonic fly extracts. Finally, the use of different variants of Dicer-2 with mutations in the DRA domain allowed me to propose a new mechanism of action for this protein.

Estudos funcionais anteriores identificaram um módulo cis-regulador (MCR) de 67 pb (-253/- 187) na região promotora do gene de pufe de DNA BhC4-1 que dirige a expressão do gene repórter na glândula anelar de Drosophila melanogaster. Uma análise bioinformática identificou 67 sequências de D. melanogaster que são similares a sequências contidas no MCR de glândula anelar. Uma das sequências identificadas reside em um fragmento genômico de 657 pb localizado aproximadamente 2500 pb à montante do CG13711, 400 pb à montante do CG12493, em uma região genômica que constitui um dos íntrons do CG32239 (Gef64C). A caracterização preliminar de três linhagens transformadas com a construção 657 pb-lacZ mostrou expressão do gene repórter no sistema traqueal de larvas e prépupas e no tórax de adultos. Baseado padrão de expressão promovido por este MCR, o mesmo foi denominado Traqueia-Tórax (TT). O principal objetivo do presente trabalho constituiu estender a caracterização molecular das linhagens da série TT-lacZ. Inicialmente embriões, larvas de primeiro, segundo e terceiro estádio, prépupas 0 h, 1 h e 2 h, pupas 24 h e adultos com 1, 3 e 5 dias foram investigados quanto ao padrão de expressão do repórter utilizando ensaio histoquímico que detecta atividade de ?-galactosidase. A expressão do gene repórter é inicialmente detectada no sistema traqueal durante o terceiro estádio larval e continua a ser detectada neste tecido em prépupas 0 h, 1 h e 2 h e pupas 24 h. Em adultos, a expressão do gene repórter é verificada nos músculos longitudinais dorsais em adultos de 3 e 5 dias. Uma vez que o MCR TT reside em uma região intergênica e a informação disponível sobre os CGs próximos ainda é escassa, não foi possível inferir qual dos CGs é regulado pelo MCR TT. Neste contexto, o padrão de expressão do RNAm do gene repórter lacZ e do CG13711, CG12493 e CG32239 foi investigado no sistema traqueal de larvas e prépupas e no tórax de adultos de uma das linhagens da série TT-lacZ utilizando RT-qPCR. Os níveis de expressão do RNAm lacZ aumentam cerca de 3 vezes em prépupas 0 horas, quando comparados com os níveis de expressão do RNAm lacZ presentes no sistema traqueal de larvas de terceiro estádio. Um padrão de expressão similar foi observado no caso do CG32239 e do CG13711. Nos tóraxes de adultos de 3 e 5 dias de idade os níveis de expressão do RNAm lacZ aumentam cerca de 37 vezes e 11 vezes, respectivamente, quando comparados aos níveis de expressão iv do RNAm lacZ presentes nos tóraxes de adultos de 1 dia. No tórax de adultos, o único CG que apresenta um padrão de expressão similar ao padrão de expressão de lacZ constitui o CG12493. Em conjunto, nós concluímos que o MCR TT promove um padrão dinâmico de expressão durante o desenvolvimento. Além disso, com base nos resultados de RT-qPCR, nós sugerimos que o MCR TT regula a expressão do RNAm do CG32239 no sistema traqueal durante a transição larva-prépupa e também a expressão do RNAm do CG12493 no tórax de adultos de 3 e 5 dias de idade. Além de estender a caracterização funcional de um novo MCR, nossos resultados também contribuem com novas informações acerca dos padrões de expressão no desenvolvimento de três CGs de D. melanogaster. / Previous functional studies identified in the DNA puff BhC4-1 promoter region a 67 bp (- 253/-187) cis-regulatory module (CRM) that drives reporter gene expression in the ring gland of D. melanogaster. A bioinformatics analysis identified 67 Drosophila melanogaster sequences that are similar to sequences contained in the ring gland CRM. One of the identified sequences resides in a 657 bp genomic fragment located about 2500 bp upstream CG13711, about 400 bp upstream CG12493, in a genomic region that constitutes one of the introns of CG32239 (Gef64C). The preliminary characterization of three transgenic lines transformed with a 657 bp-lacZ construct revealed reporter gene expression in the larval/prepupal tracheal system and in adult thorax. Based on the pattern of expression driven by this CRM we named it Trachea-Thorax (TT). The main goal of this work was to extend the molecular characterization of the lines of the TT-lacZ series. Initially ?-galactosidase histochemical assays were performed in embryos, first, second and third instar larvae, 0h, 1h and 2h prepupae, 24 h pupae and 1, 3 and 5 days old adults. Reporter gene expression is initially detected during the third larval instar in the tracheal system and continues to be detected in this tissue at 0 h, 1h and 2 h prepupa and, 24 h pupa. During the adult stage, reporter gene expression is verified in the dorsal longitudinal muscles of 3 and 5 days old adults. Since the TT CRM lies in an intergenic region and the available information about the nearby CGs is still scarce it was not possible to infer which of the CGs is regulated by the TT CRM. In this context, the mRNA pattern of expression of the lacZ reporter gene and of CG13711, CG12493 and CG32239 was investigated in the tracheal system of both larvae and prepupae and in adult thoraxes of one of the transgenic lines of the TT-lacZ series using RTqPCR. The lacZ mRNA expression levels increase about 3 times in 0 h prepupae when compared to the lacZ mRNA expression levels present in the tracheal system of third instar larvae. A similar pattern of expression was observed for both CG32239 and CG13711. In three and five days old adult thoraxes lacZ mRNA expression levels increase about 37 times and 11 times, respectively, when compared to lacZ mRNA expression levels present in one day old thoraxes. In the adult thorax, the only CG that presents a similar pattern of expression constitutes CG12493. Overall, we conclude that the TT CRM drives a dynamic pattern of ii expression throughout development. Additionally, based on RT-qPCR results, we suggest that the TT CRM regulates the expression of CG32239 mRNA in the tracheal system during the larvae to prepupae transition, as well as the expression of CG12493 mRNA in the thorax of 3 and 5 days old adults. Besides extending the functional characterization of a novel CRM our results also contribute new information about the developmental patterns of expression of three Drosophila melanogaster CGs.

Estudos funcionais anteriores identificaram um módulo cis-regulador (MCR) de 67 pb (-253/- 187) na região promotora do gene de pufe de DNA BhC4-1 que dirige a expressão do gene repórter na glândula anelar de Drosophila melanogaster. Uma análise bioinformática identificou 67 sequências de D. melanogaster que são similares a sequências contidas no MCR de glândula anelar. Uma das sequências identificadas reside em um fragmento genômico de 657 pb localizado aproximadamente 2500 pb à montante do CG13711, 400 pb à montante do CG12493, em uma região genômica que constitui um dos íntrons do CG32239 (Gef64C). A caracterização preliminar de três linhagens transformadas com a construção 657 pb-lacZ mostrou expressão do gene repórter no sistema traqueal de larvas e prépupas e no tórax de adultos. Baseado padrão de expressão promovido por este MCR, o mesmo foi denominado Traqueia-Tórax (TT). O principal objetivo do presente trabalho constituiu estender a caracterização molecular das linhagens da série TT-lacZ. Inicialmente embriões, larvas de primeiro, segundo e terceiro estádio, prépupas 0 h, 1 h e 2 h, pupas 24 h e adultos com 1, 3 e 5 dias foram investigados quanto ao padrão de expressão do repórter utilizando ensaio histoquímico que detecta atividade de ?-galactosidase. A expressão do gene repórter é inicialmente detectada no sistema traqueal durante o terceiro estádio larval e continua a ser detectada neste tecido em prépupas 0 h, 1 h e 2 h e pupas 24 h. Em adultos, a expressão do gene repórter é verificada nos músculos longitudinais dorsais em adultos de 3 e 5 dias. Uma vez que o MCR TT reside em uma região intergênica e a informação disponível sobre os CGs próximos ainda é escassa, não foi possível inferir qual dos CGs é regulado pelo MCR TT. Neste contexto, o padrão de expressão do RNAm do gene repórter lacZ e do CG13711, CG12493 e CG32239 foi investigado no sistema traqueal de larvas e prépupas e no tórax de adultos de uma das linhagens da série TT-lacZ utilizando RT-qPCR. Os níveis de expressão do RNAm lacZ aumentam cerca de 3 vezes em prépupas 0 horas, quando comparados com os níveis de expressão do RNAm lacZ presentes no sistema traqueal de larvas de terceiro estádio. Um padrão de expressão similar foi observado no caso do CG32239 e do CG13711. Nos tóraxes de adultos de 3 e 5 dias de idade os níveis de expressão do RNAm lacZ aumentam cerca de 37 vezes e 11 vezes, respectivamente, quando comparados aos níveis de expressão iv do RNAm lacZ presentes nos tóraxes de adultos de 1 dia. No tórax de adultos, o único CG que apresenta um padrão de expressão similar ao padrão de expressão de lacZ constitui o CG12493. Em conjunto, nós concluímos que o MCR TT promove um padrão dinâmico de expressão durante o desenvolvimento. Além disso, com base nos resultados de RT-qPCR, nós sugerimos que o MCR TT regula a expressão do RNAm do CG32239 no sistema traqueal durante a transição larva-prépupa e também a expressão do RNAm do CG12493 no tórax de adultos de 3 e 5 dias de idade. Além de estender a caracterização funcional de um novo MCR, nossos resultados também contribuem com novas informações acerca dos padrões de expressão no desenvolvimento de três CGs de D. melanogaster. / Previous functional studies identified in the DNA puff BhC4-1 promoter region a 67 bp (- 253/-187) cis-regulatory module (CRM) that drives reporter gene expression in the ring gland of D. melanogaster. A bioinformatics analysis identified 67 Drosophila melanogaster sequences that are similar to sequences contained in the ring gland CRM. One of the identified sequences resides in a 657 bp genomic fragment located about 2500 bp upstream CG13711, about 400 bp upstream CG12493, in a genomic region that constitutes one of the introns of CG32239 (Gef64C). The preliminary characterization of three transgenic lines transformed with a 657 bp-lacZ construct revealed reporter gene expression in the larval/prepupal tracheal system and in adult thorax. Based on the pattern of expression driven by this CRM we named it Trachea-Thorax (TT). The main goal of this work was to extend the molecular characterization of the lines of the TT-lacZ series. Initially ?-galactosidase histochemical assays were performed in embryos, first, second and third instar larvae, 0h, 1h and 2h prepupae, 24 h pupae and 1, 3 and 5 days old adults. Reporter gene expression is initially detected during the third larval instar in the tracheal system and continues to be detected in this tissue at 0 h, 1h and 2 h prepupa and, 24 h pupa. During the adult stage, reporter gene expression is verified in the dorsal longitudinal muscles of 3 and 5 days old adults. Since the TT CRM lies in an intergenic region and the available information about the nearby CGs is still scarce it was not possible to infer which of the CGs is regulated by the TT CRM. In this context, the mRNA pattern of expression of the lacZ reporter gene and of CG13711, CG12493 and CG32239 was investigated in the tracheal system of both larvae and prepupae and in adult thoraxes of one of the transgenic lines of the TT-lacZ series using RTqPCR. The lacZ mRNA expression levels increase about 3 times in 0 h prepupae when compared to the lacZ mRNA expression levels present in the tracheal system of third instar larvae. A similar pattern of expression was observed for both CG32239 and CG13711. In three and five days old adult thoraxes lacZ mRNA expression levels increase about 37 times and 11 times, respectively, when compared to lacZ mRNA expression levels present in one day old thoraxes. In the adult thorax, the only CG that presents a similar pattern of expression constitutes CG12493. Overall, we conclude that the TT CRM drives a dynamic pattern of ii expression throughout development. Additionally, based on RT-qPCR results, we suggest that the TT CRM regulates the expression of CG32239 mRNA in the tracheal system during the larvae to prepupae transition, as well as the expression of CG12493 mRNA in the thorax of 3 and 5 days old adults. Besides extending the functional characterization of a novel CRM our results also contribute new information about the developmental patterns of expression of three Drosophila melanogaster CGs.

Submitted by Francine Silva (francine.silva@unipampa.edu.br) on 2017-01-10T12:36:56Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) DISSERTAÇAO_SIBELE_BOLSON.pdf: 739236 bytes, checksum: 62e3dc921b3fd26e06e396f1afe89cf3 (MD5) / Made available in DSpace on 2017-01-10T12:36:56Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) DISSERTAÇAO_SIBELE_BOLSON.pdf: 739236 bytes, checksum: 62e3dc921b3fd26e06e396f1afe89cf3 (MD5) Previous issue date: 2016-08-02 / Effects of supplementation in the diet of Drosophila melanogaster (MEIGEM, 1830) with the fungus Pleurotus Citrinopileatus (SINGER, 1942) and Lentinus sajor-cashew (Fr.) Fr. and its relationship with the reproduction of fruit flies. The mushrooms of genus Pleurotus are widely used as food, rich in protein and antioxidants when added to animal feed increases its nutritional value. The fungi of this genus are noted for easily grow in a wide variety of substrates which facilitates cultivation and increases its biotechnological use. The species of fly, Drosophila melanogaster (Meigen, 1830) is a reference in biological and genetic studies, especially because it is easy to maintain in the laboratory and mainly have similar metabolic reactions to mammals. In nature uses as food yeasts that colonize fruits, flowers and fungi putrefying stage. This study aims to identify the effect of Pleurotus Citrinopileatus and Lentinus sajor-caju in Drosophila melanogaster body. First fungi were grown on rice straw, the fruiting bodies were weighed into 0,5-1,0-1,5-2,0-2,5-3,0 (g) were homogenized ration composed of flour maize (Klein et al, 1999) and supplied as feed for D. melanogaster, they were kept in chamber at 25 ° C ± 1. The counting larvae and pupae every twenty-four hours and the final number of flies. How to analyze the possible genotypic changes made to DNA extraction and PCR, these data were analyzed with the NTSYS 2.1 program. The results were tested for analysis of variance with the aid of Statistix8 program. It was observed that the mycelium of P. citrinopileatus stimulated reproduction in D. melanogaster, accelerating the reproductive cycle and the number of individuals compared with control and other species L. sajor-caju. The concentration of 1.5g of mycelium in the substrate was best expressed this feature and the one that showed genotypic change. The experiment suggests that the use of mycelium of P. citrinopileatus added to feed for D. melanogaster grown in the laboratory, it can be used as a reproductive stimulant for this organism, but its effect on genetic changes should be better investigated. / Efeito da suplementação na ração de Drosophila melanogaster (MEIGEM, 1830) com o fungo Pleurotus citrinopileatus (SINGER, 1942) e Lentinus sajor-caju (Fr.) Fr. e a sua relação com a reprodução de moscas das frutas. Os cogumelos do gênero Pleurotus são muito utilizados na alimentação humana, ricos em proteínas e antioxidantes, quando agregados a alimentação animal eleva o seu valor nutritivo. Os fungos deste gênero destacam-se por crescerem facilmente em uma ampla variedade de substratos o que facilita o seu cultivo e amplia o seu uso biotecnológico. A espécie de mosca, Drosophila melanogaster (MEIGEN, 1830) é referência em estudos biológicos e genéticos, destacando-se pela fácil manutenção em laboratório e principalmente por possuírem reações metabólicas similares a dos mamíferos. Na natureza essa espécie utiliza como alimentação leveduras que colonizam frutos, flores e fungos em estágio de putrefação. O presente trabalho objetiva identificar o efeito de Pleurotus citrinopileatus e Lentinus sajor-caju no organismo de Drosophila melanogaster. Primeiramente os fungos foram cultivados em palha de arroz, as frutificações foram pesadas em 0,5-1,0-1,5-2,0-2,5-3,0(g) que foram homogeneizadas a ração composta de farinha de milho (Klein et Al, 1999) e fornecida como alimento para D. melanogaster, estas foram mantidas em BOD a 25ºC ± 1. A contagem de larvas e pupas foi realizada a cada vinte quatro horas e o numero final de moscas foi quantificado no fim do tratamento. Como analise das possíveis alterações genotípicas fez-se a extração do DNA e PCR, esses dados foram analisados com o programa NTSYS 2.1. Os resultados foram testados quanto à análise de variância com o auxilio do programa Statistix8. Foi observado que o micélio de P. citrinopileatus estimulou a reprodução em D. melanogaster, acelerando o ciclo reprodutivo e o número de indivíduos quando comparado com o controle e com a outra espécie L. sajor-caju. A concentração de 1,5g de micélio no substrato foi a que melhor expressou essa característica e a única que demonstrou alteração genotípica. O experimento sugere que o uso do micélio de P. citrinopileatus agregado a ração para D. melanogaster cultivadas em laboratório, pode ser utilizado como estimulante reprodutivo para este organismo, porém seu efeito em alterações genéticas deve ser melhor investigado.

The aim of this thesis is to characterize metabolic changes in hemocytes during the immune response in D. melanogaster using in vivo markers as well as by measuring gene expression. The impact of the transcription factor HIF1 on the gene expression of glycolytic enzymes and its impact on the systemic metabolism was evaluated. The importance of HIF1 and LDH in the process of fighting against S. pneumoniae infection was tested as well.

abstract: The ability to tolerate bouts of oxygen deprivation varies tremendously across the animal kingdom. Adult humans from different regions show large variation in tolerance to hypoxia; additionally, it is widely known that neonatal mammals are much more tolerant to anoxia than their adult counterparts, including in humans. Drosophila melanogaster are very anoxia-tolerant relative to mammals, with adults able to survive 12 h of anoxia, and represent a well-suited model for studying anoxia tolerance. Drosophila live in rotting, fermenting media and a result are more likely to experience environmental hypoxia; therefore, they could be expected to be more tolerant of anoxia than adults. However, adults have the capacity to survive anoxic exposure times ~8 times longer than larvae. This dissertation focuses on understanding the mechanisms responsible for variation in survival from anoxic exposure in the genetic model organism, Drosophila melanogaster, focused in particular on effects of developmental stage (larval vs. adults) and within-population variation among individuals. Vertebrate studies suggest that surviving anoxia requires the maintenance of ATP despite the loss of aerobic metabolism in a manner that prevents a disruption of ionic homeostasis. Instead, the abilities to maintain a hypometabolic state with low ATP and tolerate large disturbances in ionic status appear to contribute to the higher anoxia tolerance of adults. Furthermore, metabolomics experiments support this notion by showing that larvae had higher metabolic rates during the initial 30 min of anoxia and that protective metabolites were upregulated in adults but not larvae. Lastly, I investigated the genetic variation in anoxia tolerance using a genome wide association study (GWAS) to identify target genes associated with anoxia tolerance. Results from the GWAS also suggest mechanisms related to protection from ionic and oxidative stress, in addition to a protective role for immune function. / Dissertation/Thesis / Results of GWAS for Adults Exposed to 6 H of Anoxia / Results of GWAS for Larvae Exposed to 1 H of Anoxia / Doctoral Dissertation Evolutionary Biology 2018

No description available.

Proper formation of the heart is a critical developmental event which requires strict regulation of coordinated cardial cell adhesion, alignment, and migration. The simple, tube-like heart of the fruit fly, Drosophila melanogaster, has proven to be an attractive system in which to study the regulatory pathways which control cardiogenesis. This is mainly due to its strikingly similarity to the vertebrate heart during early embryogenesis. In addition, many genes identified in association with congenital heart disease in humans have homologues in Drosophila, suggesting that this model organism has great potential to contribute to cardiovascular research. The extracellular matrix protein encoded by slit is a ligand for the receptors Robo, and Robo2 (lea). Recently, a third receptor for Slit has been identified as the heparin sulfate proteoglycan Syndecan. The main objective of this thesis was to use time lapse confocal imaging in order to develop further understanding of the mechanisms which result in heart assembly defects in slit, robo, lea, and syndecan mutants. We also aimed to gain a better understanding of the role of Syndecan within the Slit-Robo pathway and elucidate its relative contribution to development of the mature heart. In mutants homozygous for slit, as well as mutants doubly heterozygous for robo and lea, cardial cell alignment, adhesion, and synchronized migration were disrupted. The heart phenotype of syndecan homozygous mutants was similar that of slit and robo, lea, however the migration speed of cells to the midline did not seem to be affected. Based on our findings, we hypothesize that Slit may have Syndecan-dependent and Syndecan-independent functions in the heart. / Thesis / Master of Science (MSc)