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Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 42 for “"Quinolone"”.
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Quinolone mechanism of action: sensitivity, mutagenesis and tolerance
… elucidate potential targets for new therapies. Quinolones are an important class of antibiotics that target DNA replication. They bind to topoisomerase II and IV, leading to eventual DNA fragmentation and death. However, the precise mechanism by which they work is not well understood. Because …
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Investigations into quinolone and fluoroquinolone resistance in Salmonella enterica
… the therapeutic agents of choice are the fluoroquinolones, especially ciprofloxacin, which is also used in addition to third generation cephalosporins in children. Fluoroquinolone resistance is rare and is mostly detected in strains associated with foreign travel. Nevertheless, reports from …
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Microwave as an energy source in the synthesis of 2-aryl-4-quinolone alkaloids and naphthyridines
Thesis submitted in fulfilment of the requirements for the Degree of Masters of Technology: Organic Chemistry, Durban University of Technology, Durban, South Africa, 2011.
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The Total Synthesis of Pseudonocardia sp. Quinolone Natural Products and Studies Towards the Total Synthesis of 1β-Hydroxyalantolactone
… section concerns the total synthesis of six 4-quinolone natural products, four of which had never been synthesised before. These compounds were originally isolated from a soil bacterium of the genus Pseudonocardia, and bear intriguing structural resemblance to the Pseudomonas Quinolone Signal. …
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Specificity of aldehyde oxidase towards N-heterocyclic cations. Oxidation of quinolinium and related cations by aldehyde oxidase in vitro; the isolation of two products formed simultaneously from a single substrate.
… compounds. The N-heterocyclic cations and quinolones used required synthesis. Incubation of N-methylquinolinium, N-methyl-7,8-benzoquinolinium and N-phenylquinolinium yielded the corresponding 2- and 4-quinolones simultaneously. The ratio of 2- to 4-quinolone formation was found to be …
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Understanding the Genetics and Evolution of Antimicrobial Resistance in Escherichia Coli
… the effects of different chromosomal quinolone resistance mutations, and the pleiotropic effects of such mutations in Escherichia coli. I identified 50 spontaneous resistance mutants on nalidixic acid, ciprofloxacin, and levofloxacin, with mutations in regions ofgyrA,gyrB, andmarR, …
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Nutritional modeling of bacterial infections : physiology and metabolism of Pseudomonas aeruginosa during growth in cystic fibrosis sputum
… communication signal 2-heptyl-3-hydroxy-4-quinolone (the Pseudomonas quinolone signal, PQS), a critical regulator of virulence factor production, during growth in CF sputum. Further, I use chemical analyses of CF sputum samples to develop a defined, synthetic medium that can be used to …
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Design and Synthesis of Inhibitors of Mycobacterium tuberculosis Menaquinone D (Mtb MenD) as Potential Therapeutics for Tuberculosis (Tb)
… inhibitor candidates, based on the 3-carboxy-4-quinolone N-oxide framework. Process optimisation of the synthetic route for 4-quinolone N-oxide preparation enabled the assembly of a compound library, to address potential issues of solubility, hydrogen bonding interactions in the allosteric site, …
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Development and validaton of an indicator to compare antibiotic usage in secondary care in England
… and five percent as the limit for parenteral quinolone DOD of total quinolone DOD usage. It was possible to demonstrate a correlation between the IMD 2000 and primary care antibiotic prescribing rates but not between primary and secondary care antibiotic prescribing rates for the same referral …
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Anticancer and antibiotic leads from marine organis
… including two phenazines, six 2-alkyl-4-quinolones, and seven rhamnolipids. 2-Nonyl-4(1H)-quinolone and 2-(1-nonenyl)-4(1H)-quinolone displayed potent antimalarial activity, which was first reported here. Based on the metabolic profile of antibiotics from P. aeruginosa, chemical …
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Enantioselective Synthesis of Drug-like Molecules via Axially-Chiral Intermediates
… in the generation of 3,3-disubstituted quinolone-2,4-diones. The target compounds serve as potentially useful drug scaffolds, yet synthetic access to them has remained limited due to the lack of commercial availability of the corresponding enantiopure quaternary substituted amino acids. …
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Design, Synthesis and Evaluation of Organic and Metal Based Antimicrobial Agents
… the C-3 position of the well-known antibacterial quinolone structure. Two functionalities were chosen to replace the quinolone C-3 carboxylic acid, (1) the well-known carboxylic acid bioisostere, the (1H)-tetrazole, and (2) a hydroxamic acid. Both the (1H)-tetrazole and hydroxamic acid derivatives …
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Synthesis and biological research of the pseudomonas aeruginosa signaling compounds PQS and N-3-oxo-dodecanoyl-L-homoserine lactone
… 3-oxo-C12-homoserine lactone and Pseudomonas quinolone signal were synthesized so that the mammalian cellular responses to their presence via an infection could be studied. It was hypothesized that differing combinations of the signaling molecules would result in the up regulation of host …
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The characterization of pharmacokinetic properties and evaluation of in vitro drug combination efficacies of novel antimalarial compounds
… a completely different mode of action, such as a quinolone. Selected amino artemisinins and redox active phenothiazines, phenoxazines, thiosemicarbazones, and quinolone derivatives were screened for antimalarial activity and mammalian toxicity. These were found to be potently active (11 μM) to …
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Development of selective high-affinity fluorescent sensors for imaging neurotransmitters and application in cells and tissue
… of selective fluorescent sensors based on a quinolone core designed to image neurotransmitters catecholamines, serotonin and glutamate. Included are the main design strategy, synthesis, spectroscopic data (UV/Vis and fluorescence) and their applications in cells and tissue. NeuroSensor 510 …
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Biochemical Characterization of <i>Toxoplasma gondii</i> Type II NADH Dehydrogenases - Physiological Impact on Mitochondrial Functions and Energy Metabolism
… firstly addressed in this study. Previously, the quinolone-like compound 1-hydroxy-2-alkyl-4(1)quinolone (HDQ), known as a high affinity inhibitor for Yarrowia lipolytica NDH2, has been shown to effectively inhibit the replication of T. gondii. To obtain biochemical evidence that TgNDH2s are the …
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New Sensing Modalities for Bacterial and Environmental Phenomena
… (AI-2), the species-specific Pseudomonas Quinolone Signal (PQS), and the stationary phase indicator molecule indole. SERS substrates were formed by galvanic displacement, a substrate fabrication method that can be adapted to many SERS applications. Taken together, these new sensing …
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Direct arylation of 2-pyrones, coumarins, 2-pyridinones and 2-quinolones
… The 2-pyrone, coumarin, 2-pyridinone and 2-quinolone moieties are prevalent in numerous compounds which exhibit biological activity. In addition, due to the varied chemistry that these compounds display, they represent an excellent substrate scope to challenge any methodology. Chapter 1 …
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A fragment based approach to the development of novel antibacterial agents inspired by the natural product simocyclinone D8
… sought to design and synthesise a coumarin-quinolone hybrid via a fragment-based approach. Herein we exploit ortho and para directing effects of phenolic OH groups to selectively chlorinate starting materials. However, we show chlorination of reagents prior to forming a coumarin is not a …
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Photocontrol of Antibacterial Activity
… were designed with their structure based on quinolone antibiotics and a molecular switch linked in different positions. The molecular switches employed were based on the hydantoin structure and the pyrrole of the phytochrome chromophore. After their synthesis, their photochemical properties …
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