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Showing 1 to 19 of 19 for “"luxS"”.
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Biochemical Evaluation of SRH Analogs as Potential LuxS Inhibitors
… facilitated by the autoinducer AI-2. The enzyme LuxS catalyzes the formation of AI-2 from <em>S</em>-ribosyl homocysteine (SRH) in a wide variety of bacterial species. Inhibition of LuxS would therefore inhibit interspecies quorum sensing. The goal of this project is to establish biochemical …
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Biochemical Assay Optimization and Computational Screening Efforts to Identify Potential LuxS Inhibitors
… (SRH) by the enzyme LuxS and induces interspecies cell-to-cell communication. Inhibition of LuxS would therefore inhibit interspecies QS. Herein, a search for novel molecular species that will competitively bind with SRH in the LuxS binding site is performed <em>in …
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Synthesis of S-Ribosyl-L-homocysteine and Analogs Modified at the Homocysteine-C3 Position
… options against many bacterial diseases. The LuxS enzyme converts <em>S</em>-ribosyl-L-homocysteine (SRH) into homocysteine (HCys) and 4(<em>S</em>),5-dihydroxypentane-2,3-dione (DPD), which is the precursor of autoinducer-2 (AI-2). Thus, inhibitors of LuxS could prevent QS by halting the …
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Regulation and production of extracellular signaling molecules in Bacillus subtilis
… AI-2, that depends on the conserved protein LuxS. To determine the effect of luxS on regulation of transcription in B. subtilis, I performed experiments to compare the transcriptional profiles of B. subtilis when luxS was deleted or overexpressed. I found no significant change in …
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Shewanella oneidensis MR-1 cell-to-cell signaling and its influences on biogeochemical processes
… response is abolished upon deletion of luxS, the gene responsible for catalyzing AI-2. Deletion of luxS also affected biofilm formation. Within 16 hours of growth in a biofilm flow-through reactor, the luxS mutant had an inhibited ability to initiate biofilm formation. After 48 hours of …
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Intercellular communication in uropathogenic Escherichia coli and the probiotic Lactobacillus reuter
… pathogen recognition by the host. Disruption of luxS (AI-2 synthesis) in E. coli J96, did not alter growth, motility or biofilm formation, but did alter α-hemolysin activity. L. reuteri RC-14 was shown to produce AI-2 in non-traditional expression patterns. Complementation of the E. coli J96 IuxS …
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Development of an Improved Synthesis of S-D-Ribosyl-L-Homocysteine (SRH) and Progress Toward SRH Analogs Modified at the C3 Position
… is AI-2. AI-2 is biosynthesized by the enzyme LuxS from the precursor SRH. This thesis describes an improved synthesis of SRH through the exploration of different protecting group strategies. The knowledge gained from the improved synthesis of SRH is then applied toward the synthesis of SRH …
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HAEMOPHILUS INFLUENZAE AND MORAXELLA CATARRHALIS INTRA- AND INTERSPECIES QUORUM SIGNALING
… genetic determinant for AI-2 production (<italic>luxS</italic>) is highly conserved and many species possess the machinery to respond to AI-2. <italic>H. influenzae</italic> has a <italic>luxS</italic> homolog whereas <italic>M. catarrhalis</italic> does not but may still sense and respond to …
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The Functional Characterization of the LysR-Type Transcriptional Regulator QseD and the SorC-Type Transcriptional Regulator LsrR in Enterohemorrhagic Escherichia coli
… of AI-2, the cell-to-cell signaling product of LuxS, from the environment through regulation of the LsrACDB AI-2 uptake pump [8-9]. LsrK, an AI-2 kinase, has been shown to alleviate lsrACDBFG operon repression by generating the inhibitory ligand of LsrR DNA binding, phospho-AI-2 [10]. In E. …
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An Investigation of Histophilus somni Virulence Factors in Pathogenesis and Diagnosis
… is capable of forming a prominent biofilm, and luxS is known to play an important role in biofilm formation through quorum sensing, but has also been postulated to function in gene regulation. In order to further study the function of H. somni LuxS, mutants 2336::TnluxS and 2336::TnuspE were …
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Comparative and Functional Genomic Studies of Histophilus somni (Haemophilus somnus)
… somni. Functional characterization of H. somni luxS in the genomic context revealed that the gene encodes S-ribosylhomocysteinase that can complement biosynthesis of AI-2 quorum sensing signal molecules in Escherichia coli DH5alpha. It was also found that several pathogenic isolates of H. somni …
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PATTERNED BIOFILM FORMATION TO INVESTIGATE BACTERIA-SURFACE INTERACTIONS
… background. Interestingly, the mutants of <i>luxS</i> and <i>motB</i> exhibited major defects in interaction between cell clusters. The phenotype of the <i>luxS</i> mutant was successfully restored by both complementing the <i>luxS</i> gene on a plasmid and by adding the precursor of …
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Novel Virulence Factors in the Pathogenesis of Yersinia pestis Infection, the Causative Agent of Plague
… the synthetic enzyme for AI-2 substrate, luxS, leads to either no change or, paradoxically, an increase in in vivo bacterial virulence. Deletion of rbsA and lsrA genes, ABC transport components interacting with AI-2, synergistically disrupted AI-2 signaling patterns and resulted in an over …
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Survival and recovery of Escherichia coli O157:H7 during starvation at sub-optimal temperatures
… to recover on agar. The role of quorum sensing (LuxS/autoinducer-2) on starved cell recovery was investigated by supplementing PCA with quorum sensing molecules and using a mutant strain deficient in luxS, a gene encoding the synthase of autoinducer-2. The ability of starved and non-starved cells …
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Untersuchungen zum Einfluß der Pathogenitätsinseln I536 und II536 auf die Genexpression des uropathogenen Escherichia coli Stammes 536
… Protein (YgaG), das ein Analogon des LuxS-Proteins ist, gefunden. Das LuxS-Protein ist ein Bestandteil des "Quorum sensing"-Systems von Vibrio harveyi und wird in ähnlicher Form bei vielen Bakterien beschrieben. Sein Einfluß auf die Pathogenität wurde bei vielen Bakterien beschrieben. …
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Chlorid, ein neues Signalmolekül für Bakterien
… sehr ähnlich. Das fünfte identifizierte Protein, LuxS, ist in Gram-negativen an der Biosynthese von Autoinduktoren beteiligt. 9. Teile der Gene, die in H. halophilus für YvyD bzw. LuxS kodieren, wurden mit Hilfe von degenerierten Oligonukleotiden per PCR amplifiziert, kloniert und sequenziert. 10. …
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The microbiology of diabetic foot infections: a Ghanaian perspective
… and fold induction of bioluminescence in a luxS mutant V. harveyi reference strain. Quorum sensing (QS) inhibition assays using baicalin hydrate, cinnamaldehyde and 2(5H)–furanone showed considerable inhibition of K. pneumoniae and P. mirabilis biofilm formation but failed to completely …
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Investigating physiological and genetic characteristics of community acquired infections and potential antimicrobial interventions
… exposure to grapefruit EO were the /caD, luxS and sodA genes when the PVL CA MSSA biofilms was compared to the prototype community acquired strain, CA MRSA MW2. The S. aureus isolates were susceptible to the essential oils with the exception of limonene and lemon EO. Lemongrass EO …
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Investigations of Thioether Generation for S-D-Ribosyl-L-homocysteine Synthesis
<p>Creation of the thioether linkage is a fundamental step for the chemical preparation of the bacterial quorum sensing molecule <em>S</em>-D-ribosyl-L-homocysteine (SRH). Although previous preparations of SRH and its analogues have been reported in the literature, they employ assorted methods with …