Over the past century there have been substantial declines in farmland biodiversity as a result of the intensification of agricultural practice. Concerns over these declines have led to the development of agri-environment schemes designed to mitigate the effects of intensive agriculture and to benefit biodiversity. Prior to commencing this thesis it was not clear if flower-rich, pollinator-focused agri-environment schemes had a population level impact on wild bees on farmland. Whilst previous work has shown that the creation of flower-rich habitat can provide suitable foraging resources for bumblebees, little was known about the impact of this management on bumblebee population sizes and even less on whether these resources were used by and benefited solitary bees. This thesis compares bee populations between farms with and without flower-rich, pollinator focused agri-environment schemes in Hampshire and West Sussex, UK. Using genetic techniques to estimate colony density, and hence population size, farms implementing targeted schemes had a significantly higher density of bumblebee nests for the four species studied (212 nests/km2 against 112 nests/km2). However, there was no difference in the species richness of bees between these different farm types. When assessing pollen use by solitary bees, flowering plants sown as part of pollinator-focused agri-environment schemes were not widely used, representing 27% of pollen foraging observations and 23% of pollen collected by volume. Only 35% of solitary bee species were found to use sown plants for pollen to a meaningful extent, with most pollen collected from plants persisting in the wider environment. The creation of flower-rich habitat significantly increased resource availability, but did not increase resource diversity. These results indicate that if diverse bee populations are to be maintained on farmland then agri-environment schemes must be developed that effectively increase the number of flowering plant species present at the farm scale.

Defence against predators is fundamental to increasing an organism's fitness. My thesis explores this central theme in behavioural ecology using stingless bees as study organisms. The thesis contains a general introduction (Chapter 1), three data chapters (2-4) and a final discussion (5). Chapter 2 is a comparative study of aggression in nest defence among stingless bee species, and describes a new form of nest defence, suicidal biting, which is most prevalent in the genus Trigona. Chapter 3 describes a remarkable behaviour in Partamona helleri, which crashes head-first when entering its nest. An experiment suggests that this behaviour helps to avoid predation at the nest entrance. Chapter 4 studies nest defence in the hovering guards of Tetragonisca angustula, and demonstrates that through coordinated vigilance, a group level behaviour rarely observed in animals, the ability of the group to detect predators is enhanced.

El colesterol regula la localització subcel.lular de l'Anx6, i intervé en el transport de la caveolina de Golgi fins a la membrana plasmàtica. En aquest treball hem demostrat com l'Anx6 regula el transport de caveolina produint una alteració en el transport de colesterol intracel.lular des del compartiment endocític tardà fins a l'aparell de Golgi. Es va investigar la localització de la caveolina i el tràfic d'aquesta proteïna en el nostre model cel.lular, una línia transfectada de forma estable per a la sobreexpressió d'Anx6 (CHOAnx6). Hem demostrat que nivells elevats d'Anx6 provoquen una acumulació de caveolina al complex de Golgi. Aquest increment de caveolina s'associa a una acumulació de colesterol lliure als endosomes tardans, que alhora provoca una disminució dels nivells de colesterol a la membrana plasmàtica i a les membranes de Golgi. La disminució de colesterol al Golgi impedeix que la caveolina monomèrica pugui formar oligomers que és el requisit necessari perquè pugui sortir del Golgi i arribar a la membrana plasmàtica. Per això, en les cèl.lules CHOAnx6 el nombre de caveoles a la membrana està reduït fins a un 50%. Afegint consistència a aquests fets, tant l'expressió ectòpica de la proteïna NPC1 salvatge (que transporta el colesterol cap a fora dels endosomes tardans) com l'adició de colesterol soluble exogen, reverteixen l'acumulació de caveolina , que arriba amb normalitat a la membrana, i es recupera el nombre de caveoles fins a nivells control. En ambdós casos, també desapareix l'acumulació de colesterol lliure als endosomes. Aquesta reversió del fenotip també es produeix inhibint totalment la funcionalitat de l'Anx6 amb l'RNA d'interferència específic per a aquesta proteïna. Tots aquests resultats en conjunt demostren que la sobreexpressió d'Anx6 produeix una acumulació de colesterol als endosomes tardans, que fa que no arribi prou colesterol al Golgi, retenint la caveolina en aquest compartiment, i inhibint la formació de caveoles a la membrana plasmàtica. / "ANNEXIN A6-INDUCED ALTERATIONS IN CHOLESTEROL TRANSPORT AND CAVEOLIN EXPORT FROM THE GOLGI COMPLEX"TEXT:Annexin A6 (AnxA6) belongs to a family of Ca 2+ dependent membrane-binding proteins and is involved in the regulation of endocytic and exocytic pathways. We previously demonstrated that AnxA6 regulates receptor mediated endocytosis and lysosomal targeting of low-density lipoproteins and translocates to cholesterol-enriched late endosomes (LE). As cholesterol modulates he membrane binding and the cellular location of nxA6, but also affects the intracellular distribution of caveolin, we investigated the localization and trafficking of caveolin in AnxA6-expressing cells. Here, we show that cells expressing high levels of AnxA6 are characterized by an accumulation of caveolin-1 (cav-1) in the Golgi complex. This is associated with a sequestration of cholesterol in the LE and lower levels of cholesterol in the Golgi and the plasma membrane, both likely contributing to retention of caveolin in the Golgi apparatus and a reduced number of caveolae at the cell surface. Further strengthening these findings, knock down of AnxA6 and the ectopic expression of the Niemann-Pick C1 protein in AnxA6-overexpressing cells restore the cellular distribution of cav-1 and cholesterol, respectively. In summary, this study demonstrates that elevated expression levels of AnxA6 perturb the intracellular distribution of cholesterol, which indirectly inhibits the exit of caveolin from the Golgi complex.

La maladie de Niemann-Pick de type C (NPC) est une lipidose lysosomale complexe due à une mutation d’un des gènes NPC1 ou NPC2, qui codent pour ces protéines localisées dans les compartiments endo-lysosomaux (LE/LY). Leur absence altère le trafic intracellulaire et induit l’accumulation du cholestérol (Chol) dans les LE/LY. De plus, l’AnxA6 semble participer au transport vésiculaire du Chol en interagissant avec les microdomaines membranaires enrichis en Chol, ou avec le Chol lui-même. Dans ce travail, nous avons isolé des microdomaines membranaires résistant au Triton X-100 (également appelés DRMs pour detergent resistant membranes) à partir de lignée cellulaire NPC L1 ou de cellules saines. Les fibroblastes NPC contiennent plus de DRMs que les fibroblastes sains. Ceci semble être corrélé aux problèmes de transport du Chol dans les cellules NPC. Nous avons aussi montré qu’en présence de calcium, une partie de l’AnxA6 est associé aux DRMs, suggérant que l’AnxA6 participe à l’organisation de la membrane et par ce bias à l’étiologie de la maladie de NPC. Nous avons alors analysé les interactions de l’AnxA6-1 avec les microdomaines riches en Chol ainsi que l’implication de sa région flexible et de la séquence VAAEIL dans ces interactions. Leurs interactions avec des monocouches de Langmuir constituées de phosphatidylcholine, Chol et/ou d’acétate de cholestéryle. Nos résultats montrent que l’AnxA6 a la plus grande affinité pour les monocouches contenant du Chol ainsi que l’implication du groupement hydroxyle du Chol lors de ces interactions. / The Niemann-Pick type C (NPC) disease is a lysosomal lipid storage disorder caused by mutations in one of the two genes NPC1 or NPC2 encoding proteins of the late endosome/lysosome compartment (LE/LY). Defect in these proteins alters vesicular transport and leads to abnormal accumulation of cholesterol (Chol) in LE/LY. There are some lines of evidence suggesting that annexin A6 (AnxA6) participates in vesicular transport of Chol and may interact with membrane domains enriched in Chol and bind Chol. In this work we characterized the membrane microdomains resistant to Triton X-100, i.e., detergent-resistant membranes (DRMs) isolated from NPC patient-derived fibroblasts and from control cells. NPC cells contain a significantly higher amount of DRMs than the control cells that is consistent with the defect in Chol turnover in NPC cells. We also studied the mechanism of AnxA6 involvement in the NPC-induced changes in the membrane organization and showed that in the presence of calcium some AnxA6 molecules associate with the DRMs. This suggests that AnxA6 may play a role in the membrane lateral organization, contributing thus to the etiology of NPC disease. We then focused on the interaction of AnxA6-1 with Chol-rich membranes and on the involvement of its flexible region and VAAEIL sequence in these interactions. For this purpose, kinetics of the interfacial adsorption of human recombinant AnxA6 to Langmuir monolayers containing phosphatidylcholine, Chol and/or cholesteryl acetate were measured. Our data suggest that AnxA6 exhibits the highest affinity to Chol-containing monolayers and that the hydroxyl group of Chol plays a pivotal role in the AnxA6-lipid interactions in vitro.

Submitted by Fernando Souza (fernandoafsou@gmail.com) on 2017-08-31T11:18:50Z No. of bitstreams: 1 arquivototal.pdf: 3810025 bytes, checksum: b611fb5dbbb30abd5e31814b1e2dbe51 (MD5) / Approved for entry into archive by Fernando Souza (fernandoafsou@gmail.com) on 2017-08-31T15:31:19Z (GMT) No. of bitstreams: 1 arquivototal.pdf: 3810025 bytes, checksum: b611fb5dbbb30abd5e31814b1e2dbe51 (MD5) / Made available in DSpace on 2017-08-31T15:31:19Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 3810025 bytes, checksum: b611fb5dbbb30abd5e31814b1e2dbe51 (MD5) Previous issue date: 2017-02-15 / With the aim of subsidizing students with disabilities and reduced mobility in achieving equality, equity of opportunity and space in academic society in their total or partial university experience, presented himself, as objective of our research, the creation of an evaluation instrument that has as result an indicator of the level of accessibility of the university academic centers of Higher Education Institutions (IES), having as a case study the Center of Legal Sciences (CCJ) of the Federal University of Paraíba (UFPB). The developed instrument measured the accessibility of the academic structure that configures university academic centers based on technical and instrumental parameters that make up the dimensions: architectural, communicational; methodological; instrumental; programmatic and attitudinal. As a result, a global indicator was presented – Indicator A6 – which testifies to how accessible the academic university center under study, contributing to the management, mobilization, debate and evaluation of the institutional actors, in view of the importance of promoting accessibility as an empowerment for admission, permanence and completion of higher education of those historically marginalized. / Com a finalidade de subsidiar os discentes com deficiência e mobilidade reduzida no alcance da igualdade, equidade de oportunidade e espaço na sociedade acadêmica em sua total ou parcial vivência universitária, apresentou-se, como objetivo de pesquisa, a criação de um instrumento de avaliação que tem por resultado um indicador do nível de acessibilidade dos centros acadêmicos universitários das Instituições de Ensino Superior (IES), tendo, como estudo de caso, o Centro de Ciências Jurídicas (CCJ) da Universidade Federal da Paraíba (UFPB). O instrumento desenvolvido mensurou a acessibilidade da estrutura acadêmica que configura os centros acadêmicos universitários com base em parâmetros técnicos e instrumentais que compõem as dimensões: arquitetônica; comunicacional; metodológica; instrumental; programática e atitudinal. Como resultado, foi apresentado um indicador global – Indicador A6 – que atesta o quão acessível está o centro acadêmico universitário em estudo, contribuindo para a gestão, mobilização, debate e avaliação dos atores institucionais, frente à importância de se promover a acessibilidade como empoderador para o ingresso, permanência e conclusão do ensino superior daqueles historicamente marginalizados.

The transit method is considered to be one of the most promising for discovering extrasolar planets. However, the method requires photometric precision of better than ∼ 1%. If we are able to achieve this kind of accuracy, then we are set to discover extrasolar planets. The uniqueness of my experiment will lead to the discovery of transiting planets around the brightest and most important stars quicker than the competitors in the field. The importance of the transit method stems from being able to supply many more planetary parameters than other methods, which plays a crucial role in testing planet formation theories. This thesis is divided into eight chapters. The first chapter provides a general background about transits and their theory. We discuss other methods of extrasolar planet detection, recent developments, future space missions, and what we have learned so far about properties of hot Jupiters. The second chapter details the theory of signals and noise on CCDs followed by the design of the PASS0 experiment. The third chapter reports on the difference imaging data pipeline that we developed and applied to a set of PASS0 data to search for transiting planets. The fourth chapter shows how we apply the PASS0 pipeline to SuperWASP data and improve on the accuracy obtained with their aperture photometry pipeline. The fifth chapter reports on the search for variable stars from the PASS0 and SuperWASP data sets that we consider in this thesis. In the sixth chapter we perform a transit search on the PASS0 and SuperWASP data sets and report the results. In the seventh chapter we use the PASS0 pipeline to process a full season of observing data from 2007 for two recent planet discoveries, WASP-7b and WASP-8b, that have not yet been announced. We analyse their lightcurves and predict their radii. Finally we conclude in the eighth chapter.

Influenza A virus (IAV) is a major threat to human health with seasonal epidemics, occasional pandemics and emergence of new highly pathogenic strains from the animal reservoir. Our laboratory has shown that the human Annexin A6 (AnxA6) interacts with the IAV M2 proton channel and limits production of progeny IAV from infected cells. We have found that overexpression of AnxA6 impairs morphogenesis and release of progeny viruses. These findings are supported by another study showing that AnxA6 has a critical role in the late endosomal cholesterol balance and affects IAV replication and propagation in AnxA6-overexpressing cells. However, the molecular mechanism responsible for restriction of IAV morphogenesis by AnxA6 is still unclear. AnxA6 is a calcium-dependent phospholipid-binding protein which plays a major role in cellular events such as regulation of cholesterol homeostasis and membrane organisation or repair. AnxA6 is also implicated in the regulation of intracellular signalling pathways required for IAV infection. In this study, we used a combination of virology, cellular biology and biochemistry approaches to decipher the restriction mechanism of IAV by human AnxA6. We found that AnxA6 down-regulates M2 viral protein expression and impairs viral morphogenesis and budding. We also found that AnxA6 regulates chemokines and cytokines expression during viral infection, suggesting that AnxA6 triggers an innate immune response to IAV by modulating signalling pathways required for viral replication. Finally, we observed that IAV down-regulates AnxA6 expression at mRNA level during early stages of infection and at protein level during late infection, suggesting that IAV has developed a strategy to respond to AnxA6 restriction mechanism during viral infection. We conclude that it is essential to better understand the interaction between human AnxA6 and IAV to elucidate the potential of AnxA6 as an antiviral candidate.

Unsymmetrical discotic liquid crystals based on hexaazatriphenylene(HAT) have not been published until today.We have used tetrahydoxyquinone as the starting material to synthesis unsymmetrical discotic liquid crystals based on HAT and investigate their properties of liquid crystal.

Physical activity can prevent cardiovascular disease, obesity, type II diabetes and some types of cancer. With only 3.5% of adults meeting the recommended physical activity guidelines, research has focused on the regulatory factors that influence physical activity level. Genetic influence accounts for the majority of physical activity regulation. However, there is limited information on the mechanisms that affect physical activity, in part, because of a lack of reliable methods to silence genes in vivo. The purpose of this dissertation was to identify mechanisms in skeletal muscle that influence physical activity. The methods used to accomplish the purpose of this dissertation were the evaluation of Vivo-morpholinos as a gene silencing tool in skeletal muscle and brain, identification of proteins in skeletal muscle associated with increased physical activity level, and the use Vivo-morpholinos to transiently knockdown the identified skeletal muscle proteins as a means to elucidate mechanisms for the peripheral regulation of physical activity. Overall, this study showed that Vivo-morpholinos effectively silenced genes in skeletal muscle yet required the use of a pharmacological aid to achieve gene silencing in the brain. Additionally proteins associated with calcium regulation (Annexin A6 and Calsequestrin 1) and the Kreb’s (TCA) cycle were found to be over expressed in the high active animals. The knockdown of Annexin A6 and Calsequestrin 1 resulted in a significant decrease in physical activity, thus showing that calcium regulation could influence the physical activity response. While these results provide a potential mechanism for the peripheral regulation of physical activity, a side effect observed was that Vivo-morpholinos can hybridize resulting in increased mortality rates of the treatment animals. Therefore, we developed methods to alleviate the toxic effects of Vivo-morpholinos. Thus, this dissertation refined a technique for determining a gene’s effect in an in vivo model and identified two candidate proteins (Annexin A6 and Calsequestrin 1) that play a role in regulating daily physical activity.

This thesis describes the synthesis, characterisation and catalytic testing of multifunctional immobilised metal nanoparticle in metal-organic framework (MOF) materials. Combining the activity of metal nanoparticles with the porosity and Lewis acidity of metal-organic frameworks provides a single catalytic material which can perform multi-step reactions. Strategies to immobilise the metal nanoparticles within the metal-organic frameworks have been investigated. Immobilisation has been achieved by applying three different methodologies. First, deposition of metal nanoparticle precursors within mesoporous MOFs is discussed. Chapter 3 shows the effectivity of the double solvents deposition technique to achieve dispersed and small nanoparticles of around 2.7 nm. The best system combined Pd nanoparticles with MIL-101(Cr). This system was further investigated in tandem reductive amination catalysis, discussed in Chapter 4, to investigate the activity and selectivity provided by these multifunctional catalysts. Another immobilisation technique was performed by coating Pd decorated SiO2 spheres with a MOF layer. Using this technique, MOF was grown cyclically in solution, providing tuneable shell thicknesses of MOF on the metal nanoparticle decorated oxide spheres. While the homogeneity of the MOF shell needs more optimisation, it was determined that the surface charge on the spheres played an important role in the growth of MOF in the desired location. Finally, the third immobilisation technique is the core-shell growth of MOF on colloidal metal nanoparticles. Polymer-capped metal nanoparticles with well-defined shapes were synthesised and characterised. From here, the optimisation of conditions for core-shell growth of UiO-66 and MIL-100(Sc) were investigated. Conditions which provided the desired core-shell morphology were found for both MOF types. These materials were then subsequently used in tandem reductive amination catalysis and a more straightforward styrene hydrogenation. It was shown that the metal nanoparticles remain active catalysts within either MOF shell and the MOF shell stabilises the metal nanoparticle and acts as a Lewis acid catalyst.