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Enterococcus faecalis Senses Target Cells and in Response Expresses Cytolysin
Phillip S. Coburn,1
Christopher M. Pillar,2*
Bradley D. Jett,2
Michael S. Gilmore1,2*
Many virulent strains of Enterococcus faecalis produce a two-subunittoxin, termed cytolysin. Cytolysin expression is regulated byone of the subunits (CylLS'') through a quorum-sensing autoinductionmechanism. We found that when target cells are absent, the othersubunit (CylLL'') forms a complex with CylLS'', blocking itfrom autoinducing the operon. When target cells are present,however, CylLL'' binds preferentially to the target, allowingfree CylLS'' to accumulate above the induction threshold. Thus,enterococci use CylLL'' to actively probe the environment fortarget cells, and when target cells are detected, allows theorganism to express high levels of cytolysin in response.
1 Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Stanton L. Young Biomedical Research Center, Room 356, Post Office Box 26901, Oklahoma City, OK 73190, USA. 2 Department of Ophthalmology, University of Oklahoma Health Sciences Center, Stanton L. Young Biomedical Research Center, Room 356, Post Office Box 26901, Oklahoma City, OK 73190, USA.
N. Corcionivoschi, M. Clyne, A. Lyons, A. Elmi, O. Gundogdu, B. W. Wren, N. Dorrell, A. V. Karlyshev, and B. Bourke (2009)
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Cloning and Genetic Analyses of the Bacteriocin 41 Determinant Encoded on the Enterococcus faecalis Pheromone-Responsive Conjugative Plasmid pYI14: a Novel Bacteriocin Complemented by Two Extracellular Components (Lysin and Activator).