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Coming dissertations at Uppsala university

  • Towards time-resolved molecular interaction assays in living bacteria Author: João Crispim Encarnação Link: Publication date: 2019-12-18 10:48

    Rare and neglected diseases such as multidrug resistant (MDR) tuberculosis, malaria and trypanosomiasis are re-emerging in Europe. New strategies are needed to accelerate drug discovery to fight these pathogens. AEGIS is a Pan-European project that combines different technologies to accelerate the discovery of molecules suitable for drug development in selected neglected diseases. This thesis is part of the AEGIS research area that considers time in a multidisciplinary approach, combining biology, physics and mathematics to provide tools to characterize biological events for improving drug development and information about the target diseases and lead compounds.

    Real-time cell binding assays (RT-CBA) of receptor-ligand interactions are fundamental in basic research and drug discovery. However, this kind of assays are still rare on living cells, especially in the microbiology field. In this project, we apply the same high-precision assay type on bacterial systems and explored the interior of the cell with a time resolved assay.

    The effect of temperature was evaluated in the RT-CBA using LigandTracer to ensure that it was possible to use the technology in a range of temperatures suitable for bacteria. A method for attaching Gram positive and negative bacteria on the surface of a normal Petri dish, showing a high reproducibly and a high cellular viability after 16 h. With these two key steps, an RT-CBA fit for microbiology is available.

    Next, to answer biological questions, intracellular interactions were explored by expression and validation of intracellular proteins with fluorescent tags suitable for RT-CBAs. First, we used the subunit B from the Shiga toxin (STxB) as a model to understand different aspects about the internalization processes. RT-CBAs allowed to discovery new features of STxB binding and mechanism to deliver small molecules or small proteins into cancer cells. Then, for exploring intracellular interactions, insect cells were bioengineered for evaluating the ability of small molecules to internalize and bind to its target. Using Carbonic anhydrase II – sulfonamides as a model system, the molecular interaction in the cytoplasm could be measured using a quencher label approach. The development of this kind of novel RT-CBA tools provide new information about drug candidates for targets that are not properly expressed in bacterial cells.

    The assays in this project can make drug design more efficient. Furthermore, the evaluation of binding activity of the new compounds developed by AEGIS, focusing on rare/neglected diseases, in a biological environment has the potential to accelerate drug discovery for the targeted emerging diseases.

  • Where our feet have taken us : Examples of human contact, migration, and adaptation as revealed by ancient DNA Author: Alexandra Coutinho Link: Publication date: 2019-12-16 08:47

    In spite of our extensive knowledge of the human past, certain key questions remain to be answered about human prehistory. One involves the nature of cultural change in material culture through time from the perspective of how different ancient human groups interacted with one another. The other is how humans have adapted to the different environments as they migrated and populated the rest of the world from their origin in Africa. For my thesis I have investigated examples of human evolutionary history using genetic information from ancient human remains. Chapter 1 focused on the nature of possible interaction between the Pitted Ware Culture (PWC) and Battle Axe Culture (BAC) on the island of Gotland, in the Baltic Sea. Through the analysis of 4500 year old human remains from three PWC burial sites, I found that the existence of BAC influences in these burial sites was the result of cultural and not demic influence from the BAC. In chapter 2, I investigated the ancestry of a Late Stone Age individual from the southwestern Cape of South Africa. Population genetic analyses revealed that this individual was genetically affiliated with Khoe groups in southern Africa, a genetic make-up that is today absent from the Cape. Chapter 3 investigated the genetic landscape of prehistoric individuals from southern Africa. Specifically, I explored frequencies of adaptive variants between Late Stone Age and Iron Age individuals. I found an increase in disease resistance alleles in Iron Age individuals and attributed this to the effects of the Bantu expansion. Chapter 4 incorporated a wider range of trait-associated variants among a greater number of modern-day populations and ancient individuals in Africa. I found that many allele frequency patterns found in modern populations follow the routes of major migrations which took place in the African Holocene. The thesis attests to the complexity of human demographic history in general, and how migration contributes to adaptation by dispersing novel adaptive variants to populations.

  • Leveranser och unionsinterna förvärv i mervärdesskatterätten Author: Mikael Ek Link: Publication date: 2019-12-13 12:07

    Leveranser och unionsinterna förvärv i mervärdesskatterätten – Supplies and Intra-Union Acquisitions of Goods under VAT

    The objective of this thesis is to analyze the VAT rules regarding supplies and intra-union acquisitions of goods based on the notion that a purpose of harmonized VAT is to further the internal market. This objective originates from the tension that has been created between the two mentioned transaction types, where a transaction involving goods is treated one way if it is carried out domestically and another if it is done in a cross-border context.

    How transactions are classified determine different obligations for the taxable person that carries them out. Among other things, it affects the place of supply and thus which member state that has the right to tax the transaction. It also affects which kind of administrative obligations the taxable person has and where he or she needs to fulfill them.

    Since the idea of the internal market within the EU is to create an area without internal frontiers where free movement of goods (among other things) is ensured, it can be questioned if a harmonized system that treats cross-border supplies differently from domestic supplies fully improves the function of the internal market.

    To answer that question, it is necessary to study how supplies and intra-union acquisitions of goods are treated within the VAT system, both regarding the classification of the transactions and the consequences the classification result in. Further, it is also required to compare the findings regarding the VAT treatment of said rules with various benchmarks concerning how VAT rules should be constructed in light of the purpose to further the internal market.

    By conducting a study based on these parameters, it is possible to shed some light on a topic that has been intensely discussed on a European level during the last decade, namely how the VAT treatment of goods should be in the definitive VAT system.