Global ETD Search
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 33 for “"Homoserine lactone"”.
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N-(3-Oxododecanoyl)-L-Homoserine Lactone in the Breast Tumor Microenvironment
The tumor microenvironment is a well-recognized contributor to cancer progression in solid tumors. Cancer cell interactions with abnormal extracellular matrix, tumor associated immune and stromal cells, and aberrant fluid flow all contribute to cancer progression. Breast tumors are often …
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A Metabolomics-Based Analysis of Acyl-Homoserine Lactone Quorum Sensing in Pseudomonas aeruginosa
… virulence. These QS systems use diffusible acyl-homoserine lactone (AHL) signalling molecules to infer environmental parameters, including bacterial population density, and to coordinate behaviour across bacterial communities. This dissertation describes an investigation into the relationship …
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Synthesis and biological research of the pseudomonas aeruginosa signaling compounds PQS and N-3-oxo-dodecanoyl-L-homoserine lactone
… aeruginosa signaling molecules 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 …
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The synthesis and biological evaluation of a library of autoinducer-antibiotic conjugates
… also included. A second set of compounds, namely homoserine lactone analogue-ciprofloxacin conjugates were then synthesised, building on the one known report of a conjugate of a quorum sensing modulator and an antibiotic. The most active conjugate found was a cleavable conjugate of homocysteine …
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The Influence of Changes In theMolecular Structure of N-Acylhomoserine Lactones On the Complexation and Dna-Binding of Luxr Protein
… can perceive and bind cognate autoinducer N-acylhomoserine lactones (AHLs), thereby inducing a conformational change and subsequently binding to lux box-like target genes to regulate transcription. The study of the first identified quorum-sensing system, the Vibrio fischeri LuxI/LuxR paradigm, …
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Insights into the Substrate Binding Specificity of Quorum-Quenching Acylase PVDQ
The N-acyl homoserine lactone acylase, PvdQ, from human opportunistic pathogen Pseudomonas aeruginosa is a quorum-quenching enzyme that can hydrolyze the amide bond of the quorum sensing signaling N-acyl homoserine lactones (AHLs) thereby degrading the signaling molecules, inhibiting the biofilm …
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Genetic and Biochemical Characterization of the Mechanisms Concerning the TraR/AAI/TraM Mediated Quorum Sensing That Regulates Ti Plasmid Conjugation
… is achieved by producing and sensing an acyl-homoserine lactone molecule. In Agrobacterium tumefaciens , regulation of Ti plasmids conjugation is controlled in part by a quorum-sensing system consisting of four elements; the transcription activator TraR, the intercellular signal …
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Multiplexing cell-cell communication
… transcriptional logic gates, an acyl homoserine lactone-based communication module, and three inducible promoters that enable small molecule control over the conversations. Experimentally-parameterized mathematical models of the sub-components predict the steady state and dynamical …
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Role of the C-terminal domain of the <font face = "symbol">a</font> subunit of RNA polymerase in transcriptional activation of the <i>lux</i> operon during quorum sensing
… activator LuxR in the presence of an acylated homoserine lactone autoinducer molecule (3-oxo-hexanoyl homoserine lactone). LuxR, which binds to the <i>lux</i> operon promoter at position -42.5, is thought to function as an ambidextrous activator making multiple contacts with RNA polymerase …
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Mutant analysis of luminescence and autoinduction in a marine bacterium
… chemically purified and shown to be Noctanoyi- L-homoserine lactone. The genetic locus encoding the AI-2 synthase was cloned and designated ain (autoinducer). Manipulation of ain and AI-2 in V. jischeri demonstrated that the function of AI-2 appears to be to inhibit rather than to promote …
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Study of cell-cell communication using 3D living cell microarrays
… detection of a small chemical signal, an acyl-homoserine lactone. Through synthetic biology, I have engineered plasmids which express "sending" and "receiving" genes. Bacteria containing these plasmids were formed into complex 3D patterns, designed to assay signaling response. The gene …
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Enhancing energy recovery from industrial wastewater using microbial fuel cells
… The quorum sensing molecule N (-3-oxodecanoyl)-L-homoserine lactone of different concentrations was for the first time exogenously added to MFCs and its effect on biofilm formation and power production determined. The results were compared with control experiments without N …
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Influence of Indole and Mixed Culture Growth on Pseudomonas Aeruginosa Biofilm Structure
… aeruginosa, unable to produce N-acylated homoserine lactone (AHL) signals had altered biofilm structure. During mixed culture growth of P. aeruginosa with Escherichia coli, we found that E. coli production of the organic compound, indole, inhibited AHL-regulated genes in P. aeruginosa. The …
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Integrated functional anlaysis of quorum-sensing in the rice pathogenic bacterium Burkholderia glumae
… by the core genes, tofI and tofR. N-octanoyl-L-homoserine lactone, the primary QS signal molecule of B. glumae, is synthesized by tofI and binds to the cognate receptor tofR at the quorum point. However, tofI and tofR null mutants produce toxoflavin in certain growth conditions, indicating the …
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The microbiology of diabetic foot infections: a Ghanaian perspective
… P. mirabilis were found to be positive for acyl–homoserine lactone production, biofilm and persister cell producers and could resist and/or tolerate antibiotics such as ceftazidime and levofloxacin up to 1280 times their minimum inhibitory concentration. K. pneumoniae and P. mirabilis were also …
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The role of post-transcriptional regulators in pathogenesis and secondary metabolite production in Serratia sp. ATCC 39006.
… while production of the QS molecule, butanoyl homoserine lactone (BHL), was unaffected. Using transcriptional fusions, it was found that Hfq regulated the QS response regulators, SmaR and CarR. Additionally, exoenzyme production and swimming motility were decreased in the ∆hfq mutant, and …
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Engineering plant-microbe communication for synthetic symbioses
… In addition, we show that the p-coumarate homoserine lactone (pC-HSL) sensors can respond to pC-HSL biosynthesized by Pseudomonas putida grown in proximity to the plants. To the best of our knowledge, this is the first demonstration of engineered microbe-to-plant communication using a small …
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Effect of Spatial Organization and Population Ratios on the Dynamics of Quorum Sensing and Quorum Quenching in Bacteria Communities
… activation, focusing on the degradation of Acyl-Homoserine Lactone (AHL), a key QS molecule in Gram-negative bacteria linked to pathogenicity, by the AiiA enzyme in engineered AiiA-producing Salmonella Typhimurium 14028. Our findings suggest that QQ more effectively influences QS in spatial …
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Development of Methods for Structural Characterization of Pantoea stewartii Quorum-Sensing Regulator EsaR
… At high population densities, a small acyl-homoserine lactone (AHL) molecule, produced by a LuxI homologue, accumulates in the environment. The LuxR proteins bind to their respective AHL when the ligand accumulates to sufficient levels. Once bound to AHL, the holoproteins usually become …
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Shewanella oneidensis MR-1 cell-to-cell signaling and its influences on biogeochemical processes
… that S. oneidensis cannot utilize either an acyl-homoserine lactone (AHL) or AI-2 quorum sensing signal, despite previous work that indicated that it produced an AHL that would enhance it ability to growth in certain anaerobic environments. Using a variety of quorum sensing signal sensors, no …
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