Please use this identifier to cite or link to this item: https://scholarbank.nus.edu.sg/handle/10635/15314
Title: Molecular and functional characterization of the luxs/ autoinducer-2 (AI-2) quorum sensing molecule in clostridium difficile CCUG19126
Authors: LEE SEK YEW, ALEX
Keywords: quorum sensing, LuxS, autoinducer-2, C. difficile, cell signaling, virulence genes regulation
Issue Date: 19-May-2006
Citation: LEE SEK YEW, ALEX (2006-05-19). Molecular and functional characterization of the luxs/ autoinducer-2 (AI-2) quorum sensing molecule in clostridium difficile CCUG19126. ScholarBank@NUS Repository.
Abstract: The Gram-positive intestinal pathogen, Clostridium difficile harbors the luxS homolog required for the biosynthesis of autoinducer-2 (AI-2) signaling molecule involved in cell-cell communication called quorum sensing. C. difficile produces AI-2 in a growth-phase dependent manner with maximum activity in the mid- to late-logarithmic phase. The level of AI-2 was affected by environmental conditions such as osmolarity, pH and temperature. To determine the functional roles of AI-2, early-logarithmic C. difficile cells were exposed to AI-2-containing cell-free supernatant and mRNA transcripts of PaLoc genes (tcdA-C, tcdR and tcdE), cdt (ADP-ribosyltransferase CDT toxin), fbp68 (fibronectin-binding protein) and flaVPI (flagellin) were quantitated. AI-2 increased the transcript level of tcdA, tcdB, tcdE and fbp68. C. difficile AI-2 also upregulated lsrA transcription in the luxS mutant Salmonella typhimurium. These findings suggest that C. difficile uses AI-2 for intra and interspecies signaling to regulate the transcriptional expression of virulence factors.
URI: http://scholarbank.nus.edu.sg/handle/10635/15314
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02Contents.pdf88.17 kBAdobe PDF

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03Summary.pdf24.97 kBAdobe PDF

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04Chapter1_Introduction.pdf97.9 kBAdobe PDF

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05Chapter2_Lit Survey.pdf799.46 kBAdobe PDF

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06Chapter3_Materials & Methods.pdf223.75 kBAdobe PDF

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08Chapter5.pdf1.09 MBAdobe PDF

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09Chapter6.pdf564.77 kBAdobe PDF

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10Chapter7_Conclusion.pdf38.08 kBAdobe PDF

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11Chapter8_References.pdf214.4 kBAdobe PDF

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12Chapter9_Appendices.pdf1.08 MBAdobe PDF

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