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 20 for “"homoserine lactones"”.
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Raman Studies of Acyl-Homoserine Lactones
… techniques for the detection of N-acyl homoserine lactones (AHLs), which are quorum sensing molecules used in bacterial communication. The advantage of using Raman spectroscopy over other techniques is the possibility of in-situ detection of these molecules within their natural …
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Untersuchungen auf Sekundärstoffproduktion und physiologische Charakterisierung von marinen heterotrophen Bakterien aus dem deutschen Wattenmeer
… and some bacteria were tested for acylated homoserine lactones (AHL) production. Three isolates were additionally screened for synthesis of volatile metabolites, the corresponding compounds were isolated and their structure elucidated.
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I. Stereochemical Control of Chiral Assembly and Liquid Crystal Phase Formation of Nonamphiphilic Molecules in Water II. Control Bacterial Quorum Sensing and Quorum Sensing-mediated Activities Using Small Unnatural Molecules
… the synthesis of a library of squarylated homoserine lactones (SHLs) as analogues to the natural autoinducers N-acyl homoserine lactones (AHL) in Gram-negative bacteria. These SHLs were shown to have no or minimal impact of the growth of P. aeruginosa and V. fischeri, but maintain the …
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Controlling Biofouling by Surface Engineering and Molecular Inhibition
… novel squarate based molecules named squarylated homoserine lactones (SHLs), which are structural mimics of the bacterial autoinducer molecules called acylated homoserine lactones (AHLs). The synthesized brominated furanone derivatives and SHLs were found to be non-toxic to <em>E. coli</em> and …
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Approaches Towards the Synthesis of Bradyoxetin
… release chemical signal molecules (like N-acyl homoserine lactones, AHL) that increase in concentration as a function of cell density. The responses cover a large spectrum of process such as the virulence in Staphylococcus aureus, competence for DNA-uptake in Bacillus subtilis and Streptococcus …
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Signalling Molecule Production by Escherichia coli and Campylobacter jejuni
… classes of signalling molecules, including acyl-homoserine lactones (AHLs), have now been identified in numerous bacterial species. AHL production by clinical and laboratory isolates of Escherichia coli and Campylobacter jejuni has been investigated in this study. Laboratory, blood and urine …
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Engineering of the quorum quenching lactonase GcL for altered substrate specificity by rational design
… manner. Quorum sensing systems utilizing Acyl Homoserine Lactones (AHLs) are prominent in many microbial organisms and communities of high impact to human interests. These include certain agricultural and human pathogens, biofilm production, and aquatic biofouling. The structure of AHLs is …
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Dynamic Regulation of Metabolic Flux Using Orthogonal Quorum Sensing
… has focused on QS systems that utilize acyl homoserine lactones (AHL) as signaling molecules. These systems are well characterized, but pairing them in layered systems is difficult due to similarities in signals, which can cause unintended switching of the opposing control system. Here, we …
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Microbial interactions associated with biofilms attached to Trichodesmium spp. and detrital particles in the ocean
Quorum sensing (QS) via acylated homoserine lactones (AHLs) was discovered in the ocean, yet little is known about its role in the ocean beyond its involvement in certain symbiotic interactions. The objectives of this thesis were to constrain the chemical stability of AHLs in seawater, explore the …
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Evidence of Water to Human Transmission of Aeromonas Hydrophila: Critical Role of Quorum Sensing in Bacterial Virulence & Host Response
… water. Further, we delineated the role of N-acyl homoserine lactones (AHLs; autoinducer-1 [AI-1])-mediated quorum sensing (QS) in the virulence of a diarrheal isolate SSU of A. hydrophila by generating a ΔahyRI mutant. Our data suggested that AI-1-mediated QS modulated the in vitro virulence of A. …
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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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Microbial interactions associated with biofilms attached to Trichodesmium spp. and detrital particles in the ocean
Quorum sensing (QS) via acylated homoserine lactones (AHLs) was discovered in the ocean, yet little is known about its role in the ocean beyond its involvement in certain symbiotic interactions. The objectives of this thesis were to constrain the chemical stability of AHLs in seawater, explore the …
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Identification of Quorum Sensing Genes in Hypersaline Microbial Mats
… is the precursor for the production of acyl-homoserine lactones (AHL) or autoinducer-2 (AI-2) depending on the biosynthetic pathway. This suggests that the synthesis of QS signaling molecules and the QS phenomenon may be occurring in hypersaline microbial mats. These results also suggest that …
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Experimental Methods in Support of the Development of a Computational Model for Quorum Sensing in Vibrio fischeri
… system based on intercellular exchange of N-acyl-homoserine lactones is used by many proteobacteria to regulate the transcription of essential genes in a signal density-dependent manner. It is involved in a number of processes including the development of highly organized bacterial communities, …
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Gene Expression Control for Synthetic Patterning of Bacterial Populations and Plants
… patterning system responsive to two different homoserine lactones. I validated the AND gate-like behavior of this system both in cell suspension and in surface culture. Then, I used the synthetic circuit in a membrane-based spatial assay to demonstrate programmed hierarchical patterning of gene …
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Identification of Quorum Sensing Genes in Halococcus Hamelinensis SP. Nov. 100Na1
… The organic extract was analyzed for acyl-homoserine lactones (AHL) using LC-MS/MS. Two peaks that were not observed in the negative control showed the same fragmentation pattern as the used AHL standards however there was a mobility shift of the peaks in the LC chromatogram. It is …
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The Functional Characterization of QSEC a Bacterial Adrenergic Receptor and the LuxR Homologue SDIA in EHEC
… molecules, autoinducer-1 (AI-1) which are N-acyl homoserine lactones (AHL). Generally, in these systems, LuxI synthesizes the AHL that LuxR senses. EHEC does not encode a LuxI homologue, indicating that it can respond to AHLs through SdiA, but cannot produce them. EHEC uses SdiA to sense its …
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Novel small molecules for modulation of bacterial signaling pathways
… QS signaling molecules, such as N-acylated L-homoserine lactones (AHLs), indoles, N-acetyl glucosamine and other heterocyclic systems derived from halogenated furanones (Fimbrolides). Indole and glucosamine-based amides and oxo-amides were synthesized as non-native AHL mimics by applying EDC, …
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Structural and Mechanistic Roles of Novel Chemical Ligands on Quorum Sensing Transcription Regulator SdiA in Enterohemorrhagic Escherichia coli
… produced chemical signaling molecules, acyl-homoserine lactones (AHLs) [1]. However, some bacteria such as Escherichia coli (E. coli) do not produce AHLs and, therefore, their quorum sensing LuxR-type proteins are thought to be regulated by AHLs from other bacteria [2-4]. These sub-family of …
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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 …