| 1. |
- Borell, Anton, 1991-
(författare)
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In Between Competing Ideals : On the Relationships among Accounting, NPM, and Welfare
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- We know that public organizations today are expected to manage activities on multiple, and somewhat incongruent ideals. Since the development of the New Public Management (NPM) wave, public organizations have been increasingly subject to governance by markets, economic frugality and outputs for the purpose of improving efficiency. At the same time, they are also required to manage their daily work according to the ideals of needs, equity and professional expertise, which have traditionally been foundational to the realization of a welfarian agenda. Together, these requirements make up dual expectations of public organizations as well as the accounting technologies used to manage them: a form of paradoxical management that seeks to measure, evaluate and document both efficiency and welfare. But how do actors realize these plural ideals in practice? And what is the role of accounting in this? These are some of the aspects and problems with control that lie at the very heart of this dissertation.Based on 41 interviews and 28 observations in a Swedish school context, this dissertation shows how the paradoxical expectations become manifest in the design and use of accounting technologies. On the one hand, it shows how school actors attempt to integrate welfare and NPM in practice by relying on accounting technologies, which results in hybrid outcomes. On the other hand, the dissertation also shows the fragility of such a style of governance, which continuously leads to failures and breakdowns that actors have to readdress as a consequence of attempting to achieve competing ideals by relying on accounting.By leaning on governmentality as a metatheoretical framework, this dissertation contributes to some new understandings of control in public sector contexts. First, in contrast to the literature on colonization, which suggests that the expansive use of accounting is a direct threat to welfarian ideals, this dissertation shows that accounting can equally serve as a means for welfarian ideals to eclipse NPM. Second, in contrast to the stream of separation that treats the loose or minimal use of accounting as a mechanism for sealing off welfare from NPM-led intrusions, the dissertation shows that even a marginal or loose application of accounting can in fact be conceived as a threat to welfarian ideals. Third, this dissertation also provides additional understanding in relation to the hybridity approach, not only by illuminating how NPM and welfare were brought together through various hybrids, but also by showing how these hybrids were facilitated by accounting technologies, whose functions served to make integration a practically viable outcome amenable to both breakdowns and reintegration. Overall, the dissertation thus contributes to current knowledge on public sector governance in general, and more specifically about the relationships among accounting, NPM, and welfare, in terms of their entanglement, disentanglement, interdependencies, and modes of reproduction in public sector life, a gap also echoed by recent calls in research.
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| 2. |
- Nunez-Otero, Carlos, 1992-
(författare)
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Novel inhibitors of Chlamydia trachomatis virulence
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Chlamydia trachomatis is an obligate intracellular bacterium that infects over 100 million people globally every year. Chlamydia infections can be persistent, cause infertility and blindness, adding an economical burden in the healthcare systems. Moreover, Chlamydia infections are treated with broad-spectrum antibiotics that contribute to the selection of antibiotic resistant bacteria in the commensal flora. For this reason, novel compounds with specificity against C. trachomatis would be important for treatment of Chlamydia infections.We have developed a new class of substituted 2-pyridone amides that inhibited development of C. trachomatis. While bacterial growth was only affected to a limited extent, the produced progeny bacteria had impaired capacity to infect new cells. The compounds presented no toxicity in human or mouse cell lines and they did not inhibit growth of bacteria from the normal flora. Structure activity relationship (SAR) development of 2-pyridones lead to compounds with effect at nanomolar concentrations. Further modifications of the C3 part of the molecules resulted in isostere compounds with even a higher potency. By exploring the C8 position, we observed that methylsulfonamide substituents improved the pharmacokinetic properties and enabled oral uptake in mice. This discovery opens the door for oral treatment.Among 2-pyridone amides, KSK213 was one of the most potent and we investigated the mode of action on the life cycle of C. trachomatis. KSK213 reduced transcription by the end of the developmental cycle and upon infection of new host cells. Mutations in RNA helicase and RNAse III genes, involved in transcription, mediated resistance to KSK213. It also attenuated the infectivity in a mouse vaginal infection model. To further explore the molecular target for 2-pyridone amides in Chlamydia, we used a custom synthesized probe for affinity chromatography approaches.Here we show that 2-pyridones are potent non-toxic inhibitors of C. trachomatis that can be chemically modified to increase potency and enable oral bioavailability. These molecules have the potential to treat and prevent Chlamydia infections without affecting the normal flora.
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| 3. |
- Knutsson, Sofie, 1983-
(författare)
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Towards Mosquitocides for Prevention of Vector-Borne Infectious Diseases : discovery and Development of Acetylcholinesterase 1 Inhibitors
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Diseases such as malaria and dengue impose great economic burdens and are a serious threat to public health, with young children being among the worst affected. These diseases are transmitted by mosquitoes, also called disease vectors, which are able to transmit both parasitic and viral infections. One of the most important strategies in the battle against mosquito-borne diseases is vector control by insecticides and the goal is to prevent people from being bitten by mosquitoes. Today’s vector control methods are seriously threatened by the development and spread of insecticide-resistant mosquitos warranting the search for new insecticides. This thesis has investigated the possibilities of vector control using non-covalent inhibitors targeting acetylcholinesterase (AChE); an essential enzyme present in mosquitoes as well as in humans and other mammals. A key requirement for such compounds to be considered safe and suitable for development into new public health insecticides is selectivity towards the mosquito enzyme AChE1. The work presented here is focused on AChE1 from the disease transmitting mosquitoes Anopheles gambiae (AgAChE1) and Aedes aegypti (AaAChE1), and their human (hAChE) and mouse (mAChE) counterparts. By taking a medicinal chemistry approach and utilizing high throughput screening (HTS), new chemical starting points have been identified. Analysis of the combined results of three different HTS campaigns targeting AgAChE1, AaAChE1, and hAChE allowed the identification of several mosquito-selective inhibitors and a number of compound classes were selected for further development. These compounds are non-covalent inhibitors of AChE1 and thereby work via a different mechanism compared to current anti-cholinergic insecticides, whose activity is the result of a covalent modification of the enzyme. The potency and selectivity of two compound classes have been explored in depth using a combination of different tools including design, organic synthesis, biochemical assays, protein X-ray crystallography and homology modeling. Several potent inhibitors with promising selectivity for the mosquito enzymes have been identified and the insecticidal activity of one new compound has been confirmed by in vivo experiments on mosquitoes. The results presented here contribute to the field of public health insecticide discovery by demonstrating the potential of selectively targeting mosquito AChE1 using non-covalent inhibitors. Further, the presented compounds can be used as tools to study mechanisms important in insecticide development, such as exoskeleton penetration and other ADME processes in mosquitoes.
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| 4. |
- Kulén, Martina, 1988-
(författare)
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New alternatives to combat Listeria monocytogenes and Chlamydia trachomatis : Design, synthesis, and evaluation of substituted ring-fused 2-pyridones as anti-virulent agents
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Antibiotic resistance has become a global health burden with the number of resistant bacteria continuously increasing. Antibiotic drugs act by being either bactericidal (killing bacteria) or bacteriostatic (inhibiting growth of bacteria). However, these modes of action increase the selective pressure on the bacteria. An alternative treatment strategy to antibiotics is anti-virulence therapies that inhibits virulence of the pathogenic bacteria. The term “virulence” summarises a number of factors that the bacteria need to colonise a new niche and as a consequence its ability to infect and cause diseases. By inhibiting virulence, instead of killing, the selective pressure on the bacteria can be reduced and consequently decreases the rapid development of resistance. This thesis describes two projects focusing on development of anti-virulence agents, with the ring-fused 2-pyridone scaffold as the central character, targeting the bacteria Listeria monocytogenes and Chlamydia trachomatis.The first project is targeting L. monocytogenes, which is the cause for listeriosis in humans. This can develop into life-threatening encephalitis and meningitis as well as cause severe complications for developing fetus. The target in L. monocytogenes is the transcriptional regulator PrfA that control almost all virulence factors in this bacterium. We have designed and synthesised potent substituted ring-fused 2-pyridones, which at low micromolar concentrations block activation of the virulence regulator PrfA and thus attenuate the bacterial infection. Co-crystallisation of the active ring-fused 2-pyridones with PrfA resulted in determination of the exact substance interaction site in the protein. This facilitated further structure-based design that resulted in improved compounds capable of attenuating L. monocytogenes in an in vivo model.The second project targets C. trachomatis, which is the causative agent behind the most common sexually transmitted infection as well as the eye infection trachoma. By structure-activity relationship analysis of previously tested ring-fused 2-pyridones, we have designed and synthesised non-hydrolysable ring-fused 2-pyridone amide isosteres. The most potent analogues inhibit C. trachomatis infectivity at low nanomolar concentrations, without showing host cell toxicity or affecting the viability of commensal microbiota. Introduction of heteroatom substituents at specific sites of the ring-fused 2-pyridone scaffold, resulted in improved pharmacokinetic properties of the analogues and further evaluation in vivo was performed.
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| 5. |
- Oelker, Melanie, 1988-
(författare)
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Disarming bacteria : a structure-based approach to design an anti-virulence drug against Listeria monocytogenes
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Antibiotic resistances are one of the biggest threats to global health and if we don’t change our behavior and way of using antibiotics we will end up in a ‘post-antibiotic era’, in which common infections and minor injuries can once kill again and up to 10 million deaths per year may occur by 2050. Therefore, there is a high need for new anti-bacterial drugs, especially of alternatives to existing antibiotics with already described resistances. Classical antibiotics target the essential processes of survival and growth in bacteria and therefore put a high selective pressure on them to develop resistances. In contrast, the ability to infect or damage a host, the virulence, is less essential for bacteria. Thus, targeting the virulence is supposed to cause a lower selective pressure and this alternative mode-of-action could help to decelerate the development of antibiotic resistances.The aims in this work were to proceed with the structure-based design of an anti-virulence drug against the food-borne pathogen Listeria monocytogenes, but also to deepen our understanding of the complex regulation system for the virulence of this bacterium. PrfA, the master regulator of virulence in Listeria monocytogenes, is a member of a large family of bacterial transcription factors, which are regulated by a conformational change and allosteric modulation by different regulator molecules. Furthermore, its critical role in virulence regulations makes is a suitable target for an anti-virulence drug. In this work new lead compounds based on the previously identified ring-fused 2-pyridone scaffold were designed, synthesized and analyzed by different biological, biophysical, computational and structural biology methods. Three new binding sites and binding modes of these compounds in PrfA were evaluated for their potential use in future designs and a compound with improved activity was identified. In a second study another structurally different lead compound was discovered to inhibit PrfA. Furthermore, the studies on proposed natural regulators of PrfA uncovered the underlying mechanism for the virulence regulation by the peptide signature of the environment and in a follow-up study the structural basis of the binding of inhibitory peptides to PrfA was further investigated. Finally, a structural review on all available structure of PrfA provided more insights into the allosteric regulation mechanism of PrfA activity.This work will hopefully support in the successful development of an anti-virulence drug against Listeria monocytogenes and thus contribute to the reduction of the problem of antibiotic resistances.
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| 6. |
- Adolfsson, Dan E., 1989-
(författare)
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Synthesis of Ring-fused Peptidomimetics : Interacting with Amyloid Fibrils
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Parkinson's and Alzheimer's disease are the two most common neurological disorders in humans. Both conditions involve progressive death of neurons in the central nervous system, decline in bodily functions and eventually (and invariably), death. So far, no cure exists and the available treatments can only ease symptoms. Despite substantial investments in research, the biomolecular processes are still far from fully understood. However, both diseases are associated with formation of fibrillar protein aggregates called amyloid deposits. Whereas Alzheimer’s disease involves aggregation of the Tau and Amyloid β proteins, α-Synuclein fibrilization plays a key role in Parkinson's disease. Although they are chemically distinct, the deposits consist of protein fibres with similar morphology and fold. Small molecules, such as the thiazoline fused 2-pyridones herein presented, can interfere with the formation of amyloid fibres, or bind to them. Besides having potential for diagnostication and treatment, such small molecules constitute valuable tool compounds in future research, to unravel the mechanisms of amyloid formation and pathology. The first step towards successful treatment, diagnostication and prevention of Alzheimer's and Parkinson's disease is understanding the causes and underlying mechanisms better. This thesis narrates the synthesis and development of novel chemical structures: multi ring fused peptidomimetics with the ability to bind mature amyloid fibrils, consisting of α-Synuclein or Amyloid β. The first project (articles I, III and VI) describes method development for the extension of bicyclic thiazolino 2-pyrdiones by fusion with aromatic nitrogen heterocycles, which enables the desired amyloid binding properties. Derivatisations of the newly generated central scaffold, and variation of the multiple attached substituents, were subsequently performed in efforts to improve binding strength and solubility, and gain selectivity towards certain fibrils. One of the most promising amyloid fibril binders was evaluated in a human cell line and in mice, and found to be protective against accelerator induced neurotoxicity. One pyrimidine fused compound moreover indicated potent inhibition of Amyloid b aggregation. The second project (articles II, IV and V) focuses on development of methods to modify the thiazoline ring. Ring opening induced by electrophiles generates N-alkenyl 2-pyridones but decreases amyloid binding potency. Introduction of a cyclobutane moiety fused with the thiazoline ring is better tolerated, and adds a terminal alkene moiety that can be exploited in future chemical modifications. Expansion of the five membered thiazoline ring to a six membered dihydrothiazine ring, equipped with a nitrophenyl substituent, provides compounds with enhanced fibril binding capacity, which further inhibits Amyloid β fibril formation in vitro. Taken together, the synthetic methodologies allow construction and late stage modification of complex fused heterocycles, with several points of variation. Thus, the developed methods may be of future value in our laboratories and elsewhere.
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| 7. |
- Aliashkevich, Alena, 1990-
(författare)
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Molecular mechanisms and biological consequences of the production of non-canonical D-amino acids in bacteria
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Most bacteria possess a vital net-like macromolecule – peptidoglycan (PG). PG encases bacteria around the cytoplasmic membrane to withstand the high internal turgor pressure and thereby protect the cell from bursting. In addition, PG is a major morphological determinant of bacteria being both required and sufficient to maintain cell shape. During cell growth PG hydrolysis and synthesis are tightly controlled to keep proper cell shape and integrity at all times. Given the essentiality of PG for bacterial growth and survival, the synthesis of this polymer is a major target of many natural and synthetic antibiotics (e.g. penicillins, glycopeptides).For a long time, PG composition was considered to be conserved and static, however it’s now being recognized as a dynamic and plastic macromolecule. The structure and chemistry of PG is influenced by a myriad of environmental cues that include interkingdom/interspecies interactions. Recently, it was found that a wide set of non-canonical D-amino acids (D-amino acids different from D-Ala and D-Glu, NCDAAs) are produced and released to the extracellular milieu by diverse bacteria. In Vibrio cholerae these NCDAAs are produced by broad-spectrum racemase enzyme (BsrV) and negatively regulate PG synthesis through their incorporation into PG. We have shown that in addition to D-Met and D-Leu, which were reported previously, V. cholerae also releases high amounts of D-Arg, which inhibits a broader range of phylogenetically diverse bacteria. Thus, NCDAAs affect not only the producer, but might target other species within the same environmental niche. However, in contrast to D-Met, D-Arg targets cell wall independent pathways. We have shown that non-proteinogenic amino acids also can be racemized by Bsr. A plant amino acid L-canavanine (L-CAN) is converted into D-CAN by a broad-spectrum amino acid racemase (BSAR) of the soil bacterium Pseudomonas putida and subsequently released to the environment. D-CAN gets highly incorporated into the PG of Rhizobiales (such as Agrobacterium tumefaciens, Sinorhizobium meliloti) thereby affecting the overall PG structure, bacterial morphogenesis and growth fitness. We found that detrimental effect of D-CAN in A. tumefaciens can be suppressed by a single amino acid substitution in the cell division PG transpeptidase penicillin-binding protein 3a (PBP3a). Rhizobiales are a polar-growing species that encode multiple LD-transpeptidases (LDTs), enzymes that normally perform PG crosslinking, but that can also incorporate NCDAAs into termini of the PG peptides. As these species incorporate high amounts of D-CAN in their PG, we hypothesized that LDTs might represent the main path used by NCDAAs to edit A. tumefaciens’ PG and cause their detrimental effects. Therefore, we decided to further explore the significance of LDT proteins for growth and morphogenesis in A. tumefaciens. While in the Gram-negative model organism E. coli LDT proteins are non-essential under standard laboratory conditions, we found that A. tumefaciens needs at least one LDT for growth out of the 14 putative LDTs encoded in its genome. Moreover, clustering the LDT proteins based on their sequence similarity revealed that A. tumefaciens has 7 LDTs that are exclusively present among Rhizobiales. Interestingly, the loss of this group of LDTs (but not the rest) leads to reduced growth, lower PG crosslinkage and rounded cell phenotype, which suggests that this group of Rhizobiales- specific LDTs have a major role in maintaining LD-crosslinking homeostasis, which in turn is important for cell elongation and proper shape maintenance in A. tumefaciens.
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| 8. |
- Andersson, Hans, 1978-
(författare)
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Reaction Between Grignard reagents and Heterocyclic N-oxides : Synthesis of Substituted Pyridines, Piperidines and Piperazines
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis describes the development of new synthetic methodologies for preparation of bioactive interesting compounds, e.g. substituted pyridines, piperidines or piparazines. Thesecompounds are synthesized from commercially available, cheap and easily prepared reagents, videlicet the reaction between Grignard reagents and heterocyclic N-oxides. The first part of this thesis deals with an improvement for synthesis of dienal-oximes and substituted pyridines. This was accomplished by a rapid addition of Grignard reagents to pyridine N-oxides at rt. yielding a diverse set of substituted dienal-oximes. During these studies, it was observed that the obtained dienal-oxmies are prone to ring-close upon heating. By taking advantage of this, a practical synthesis of substituted pyridines was developed. In the second part, an ortho-metalation of pyridine N-oxides using Grignard reagents is discussed. The method can be used for incorporation of a range of different electrophiles, including aldehydes, ketones and halogens. Furthermore, the importance for incorporation of halogens are exemplified through a Suzuki–Miyaura coupling reaction of 2-iodo pyridine N-oxides and different boronic acids. Later it was discovered that if the reaction temperature is kept below -20 °C, the undesired ringopening can be avoided. Thus, the synthesis of 2,3-dihydropyridine N-oxide, by reacting Grignard reagents with pyridine N-oxides at -40 °C followed by sequential addition of aldehyde or ketone, was accomplished. The reaction provides complete regio- and stereoselectivity yielding trans-2,3-dihydropyridine N-oxides in good yields. These intermediate products could then be used for synthesis of either substituted piperidines, by reduction, or reacted in a Diels–Alder cycloaddtion to give the aza-bicyclo compound. In the last part of this thesis, the discovered reactivity for pyridine N-oxides, is applied on pyrazine N-oxides in effort to synthesize substituted piperazines. These substances are obtained by the reaction of Grignard reagents and pyrazine N-oxides at -78 °C followed by reduction and protection, using a one-pot procedure. The product, a protected piperazine, that easily can be orthogonally deprotected, allowing synthetic modifications at either nitrogens in a fast and step efficient manner. Finally, an enantioselective procedure using a combination of PhMgCl and (-)-sparteine is discussed, giving opportunity for a stereoselective synthesis of substituted piperazines.
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| 9. |
- Arja, Katriann, 1985-
(författare)
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Multimodal Porphyrin-Based Conjugates : Synthesis and characterization for applications as amyloid ligands, photodynamic therapy agents and chiroptical materials
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Organic compounds that interact both with certain biological targets and display specific photophysical properties can be utilized as molecular tools to visualize and possibly effect disease related processes taking place in living organisms. In this regard, porphyrins are a class of naturally occurring molecules that possess intriguingly interesting photophysical properties where they can act as luminescent probes by emitting detectable light, as well as photosensitizers in the light mediated therapy called photodynamic therapy. In this thesis, the porphyrin structure has been synthetically combined with other molecule classes to achieve compounds with desirable multimodal characteristics.Firstly, luminescent conjugated oligothiophenes (LCOs) that have extensively, and with great success, been utilized as fluorescent ligands for amyloid formations, have been conjugated to porphyrins to render oligothiophene porphyrin hybrids (OTPHs) comprising two optically active modalities. When applied as fluorescent amyloidophilic dyes for visualization of amyloid-β (Aβ), one of the pathological hallmarks in Alzheimer’s disease, an enhanced optical assignment of distinct aggregated forms of Aβ was afforded. Thus, properly functionalized OTPHs could give us more information about pathological processes underlying devastating disorders, such as Alzheimer’s disease. In addition, the OTPHs can be associated with synthetic peptides inducing peptide folding into certain three-dimensional helical structures giving rise to novel optically active materials.Secondly, this thesis also embraces porphyrins’ potential as photosensitizers in photodynamic therapy to kill cancer cells. Grounded on the prerequisites for an optimal photosensitizer, we designed porphyrin-based conjugates equipped with common carbohydrates for improved cancer cell selectivity and with a fluorinated glucose derivative, 2-fluoro 2-deoxy glucose, for advantageous metabolism in cancer cells. Furthermore, incorporation of a radioisotopic fluorine-18 atom into the glycoporphyrins could give the means for diagnostic use of the conjugates in positron emission tomography (PET).In order to tether together the above-mentioned molecular moieties in a controlled fashion, we developed a robust synthetic strategy for asymmetrical functionalization of porphyrin core. The method involves chlorosulfonation of this otherwise inert tetrapyrrolic structure, followed by alkynylation. Parallelly to amide coupling reactions, copper(I)-catalyzed alkyne azide cycloaddition is used for fast and high-yielding late-stage conjugations. Overall, this thesis demonstrates how combining different molecular moieties in synthetic organic chemistry yields novel molecules with combined and improved multimodal properties for biological and medicinal applications, guided by the design-by-function methodology.
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| 10. |
- Bengtsson, Christoffer, 1979-
(författare)
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Synthesis of substituted Ring-Fused 2-Pyridones and applications in chemical biology
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Antibiotics have been extensively used to treat bacterial infections since Alexander Fleming’s discovery of penicillin 1928. Disease causing microbes that have become resistant to antibiotic drug therapy are an increasing public health problem. According to the world health organization (WHO) there are about 440 000 new cases of multidrug-resistant tuberculosis emerging annually, causing at least 150 000 deaths. Consequently there is an immense need to develop new types of compounds with new modes of action for the treatment of bacterial infections.Presented herein is a class of antibacterial ring-fused 2-pyridones, which exhibit inhibitory effects against both the pili assembly system in uropathogenic Escherichia coli (UPEC), named the chaperone usher pathway, as well as polymerization of the major curli subunit protein CsgA, into a functional amyloid fibre. A pilus is an organelle that is vital for the bacteria to adhere to and infect host cells, as well as establish biofilms. Inhibition of the chaperone usher pathway disables the pili assembly machinery, and consequently renders the bacteria avirulent.The focus of this work has been to develop synthetic strategies to more efficiently alter the substitution pattern of the aforementioned ring-fused 2-pyridones. In addition, asymmetric routes to enantiomerically enriched key compounds and routes to compounds containing BODIPY and coumarin fluorophores as tools to study bacterial virulence mechanisms have been developed. Several of the new compounds have successfully been evaluated as antibacterial agents. In parallel with this research, manipulations of the core structure to create new heterocycle based central fragments for applications in medicinal chemistry have also been performed.
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