Deletion of sigma54 (rpoN) alters the rate of autolysis and biofilm formation in Enterococcus faecalis

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Show simple item record Hancock, Lynn E. Iyer, Vijayalakshmi Subramanian 2012-06-14T14:37:53Z 2012-06-14T14:37:53Z 2012-06-14
dc.description.abstract Transcription initiation is a critical step in bacterial gene regulation and is often controlled by transcription regulators. The alternate sigma factor (sigma54) is one such regulator that facilitates activator-dependent transcription initiation and thus modulates the expression of a variety of genes involved in metabolism and pathogenesis in bacteria. This study describes the role of sigma54 in the nosocomial pathogen Enterococcus faecalis. Biofilm formation is one of the important pathogenic mechanisms of E. faecalis, as it elevates the organism’s potential to cause surgical site and urinary tract infections. Lysis of bacterial cells within the population contributes to biofilm formation by providing extracellular DNA (eDNA) as a key component of the biofilm matrix. Deletion of rpoN rendered E. faecalis resistant to autolysis, which in turn impaired eDNA release. Despite the significant reduction in eDNA levels compared to the parental strain, the rpoN mutant formed more robust biofilms as observed using laser scanning confocal microscopy and Comstat analysis, indicating and emphasizing the presence of other matrix components. Initial adherence to a polystyrene surface was also enhanced in the mutant. Proteinase K treatment at early stages of biofilm development significantly reduced the accumulation of biofilm by the rpoN mutant. In conclusion, our data indicate that other factors in addition to eDNA might contribute to the overall composition of the enterococcal biofilm and that the regulatory role of sigma54 governs the nature and composition of the biofilm matrix. en_US
dc.relation.uri en_US
dc.subject Enterococcus faecalis en_US
dc.subject σ54 (rpoN) en_US
dc.subject Biofilm en_US
dc.subject Extracellular DNA en_US
dc.subject Autolysis en_US
dc.subject Sigma54 (rpoN) en_US
dc.title Deletion of sigma54 (rpoN) alters the rate of autolysis and biofilm formation in Enterococcus faecalis en_US
dc.type Article (author version) en_US 2012 en_US
dc.citation.doi doi:10.1128/JB.06046-11 en_US
dc.citation.epage 375 en_US
dc.citation.issue 2 en_US
dc.citation.jtitle Journal of Bacteriology en_US
dc.citation.spage 368 en_US
dc.citation.volume 194 en_US
dc.contributor.authoreid lynnh en_US
dc.contributor.authoreid vsi en_US

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