Journal Article


Colin Hill
Cormac G M Gahan
Mark S Waidmann
Pat G. Casey
Ian R. Monk
Christian U Riedel



animals pathogenicity genes bacterial mice inbred balb c biofilms female rna bacterial genetics microbiology metabolism listeria monocytogenes listeriosis quorum sensing gene expression profiling genetic complementation test sequence deletion virulence caco 2 cells mice gene expression regulation bacterial oligonucleotide array sequence analysis humans bacterial proteins

AgrD-dependent quorum sensing affects biofilm formation, invasion, virulence and global gene expression profiles in Listeria monocytogenes. (2009)

Abstract The Listeria monocytogenes Agr peptide-sensing system has been analysed by creating a deletion mutant in agrD, the structural gene for the putative quorum-sensing peptide. The DeltaagrD mutant displayed significantly reduced biofilm formation, a defect which could be restored by genetic or physical complementation. A reduced invasion of Caco-2 intestinal epithelial cells was observed for the DeltaagrD mutant while phagocytosis by THP-1 macrophages was unaffected. Additionally, the level of internalin A (InlA) in the cell wall was decreased in the DeltaagrD mutant. Expression profiling of virulence genes (hlyA, actA, plcA, prfA and inlA) identified a finely tuned regulation which resulted in an impaired virulence response in the DeltaagrD mutant. The mutant is also significantly attenuated for virulence in mice, as revealed by bioluminescent in vivo imaging. On day 3 post infection, systemic dissemination to livers and spleens had occurred for the wild type, whereas the DeltaagrD mutant remained localized to the liver. Microarray analysis identified 126 and 670 genes as significantly regulated in exponential and stationary phase respectively. The results presented here suggest that peptide sensing plays an important role in the biology of L. monocytogenes, with relevant phenotypes in both the saprophytic and parasitic lifecycles.
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Full list of authors on original publication

Colin Hill, Cormac G M Gahan, Mark S Waidmann, Pat G. Casey, Ian R. Monk, Christian U Riedel

Experts in our system

Colin Hill
University College Cork
Total Publications: 351
Cormac G M Gahan
University College Cork
Total Publications: 109
Pat G. Casey
University College Cork
Total Publications: 40