An investigation of the regulation and physiological role of Listeria monocytogenes extracellular polymer

Wong, Ho Ting Lawrence (2013) An investigation of the regulation and physiological role of Listeria monocytogenes extracellular polymer. PhD thesis, University of Nottingham.

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It was shown that Listeria monocytogenes cells grown in a defined minimal, MCDB202, showed enhanced extracellular polymeric substances production compared to BHI. On the other hand, it was reported that in L. monocytogenes luxS mutant, AI-2 reduction and biofilm enhancement were seen. It is hypotheses that there could be a linkage between the AI-2 signaling system and the EPS formation. The expression of EPS could be induced by the reduction in AI-2.

The main aim of the research is to study this EPS formation in minimal media, how is it linked to AI-2 production, the function of the EPS as well as to figure out the linkage between EPS formation with cap genes found in Listeria genome.

It was shown that MCDB202 have caused an increase in surface hydrophobicity of the cells. However, cells grown in the defined media did not induced better attachment and biofilm formation towards hydrophobic surfaces. And cells grown in MCDB202 were shown less capable to infect eukaryotic cells in the cell invasion assay. On the other hand, AI-2 production was shown to be relative lower in Listeria cell grown in minimal media MCDB202) than rich media (BHI). Bioinformatics study has shown that only capA homologues, but no capBCDE homologues, were found in Listeria genome. However, the bioinformatics works have shown that the capA homologues are unlikely to be contributing the EPS seen produced in Listeria monocytogenes. This was further supported in the expression assay that the two genes were not highly expressed in MCDB media.

Item Type: Thesis (University of Nottingham only) (PhD)
Supervisors: Rees, Catherine
Hill, Philip
Subjects: Q Science > QR Microbiology
Faculties/Schools: UK Campuses > Faculty of Science > School of Biosciences
Item ID: 12948
Depositing User: EP, Services
Date Deposited: 10 Sep 2013 08:42
Last Modified: 17 Sep 2016 01:36

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