Project description:Analysis of changes in gene expression in Enterococcus faecalis OG1 delta-EF2638 mutant compared to wild-type OG1 strain. The deletion mutant has a growth defect when grown with aeration The mutant presented in this study is described and characterized in Vesic, D. and Kristich, C.J. 2012. A Rex-family transcriptional repressor influnces H2O2 accumulation by Enterococcus faecalis. (submitted for publication)
Project description:To investigate the transcriptional changes that Enterococcus faecalis undergoes during agar surface-penetration, which promote cell envelope remodeling and tolerance to stress.
Project description:To further investigate the homeostatic response of E. faecalis to Fe exposure, we examine the whole-genome transcriptional response of wild-type (WT) exposed to non toxic Fe excess. This experiment correspond the work titled Transcriptomic response of Enterococcus faecalis to iron excess (work in preparation) A four chip study using total RNA recovered from four separate wild-type cultures of Enterococcus faecalis OG1RF, two controls samples (N medium growth) and two iron samples (N medium gowth with 0.5 mM Fe-NTA). Each chip measures the expression level of 3,114 genome genes from Enterococcus faecalis strain V583 (A7980-00-01).
Project description:To further investigate the homeostatic response of E. faecalis to Fe exposure, we examine the whole-genome transcriptional response of wild-type (WT) exposed to non toxic Fe excess. This experiment correspond the work titled Transcriptomic response of Enterococcus faecalis to iron excess (work in preparation)
Project description:Enterococcus faecalis is a Gram-positive bacterium that is a major cause of hospital-acquired infections due to its intrinsic resistance to cell wall-active antimicrobials. One critical determinant of this resistance is the transmembrane kinase IreK, which belongs to the PASTA kinase family of bacterial signaling proteins involved with the regulation of cell wall homeostasis. IreK has enhanced activity in response to cell wall stress, but direct substrates of IreK phosphorylation leading to antimicrobial resistance are largely unknown. To better understand stress-modulated phosphorylation events contributing to virulence, wild type E. faecalis treated with cell wall-active chlorhexidine and ceftriaxone were examined via phosphoproteomics. Among the most prominent changes were increased phosphorylation of divisome components after both treatments, implicating cell division proteins in antimicrobial defense signaling. Phosphorylation mediated by IreK was then determined via similar analysis with a E. faecalis ΔireK mutant strain, revealing potential IreK substrates involved with the formation/maintenance of biofilms and within the E. faecalis two-component system, another common signal transduction pathway for antimicrobial resistance. These results reveal critical insights into the biological functions of IreK and the mechanisms of E. faecalis antimicrobial resistance.
Project description:Analysis of changes in gene expression in Enterococcus faecalis OG1 delta-EF2638 mutant compared to wild-type OG1 strain. The deletion mutant has a growth defect when grown with aeration The mutant presented in this study is described and characterized in Vesic, D. and Kristich, C.J. 2012. A Rex-family transcriptional repressor influnces H2O2 accumulation by Enterococcus faecalis. (submitted for publication) Microarray analysis was done using RNA isolated from two independent cultures of wild-type Enterococcus faecalis OG1 and two independent cultres of Enterococcus faecalis OG1 delta-EF2638 mutant; each RNA sample was subjected to triplicate hybridization (technical replicates) . Microarrays were custom designed to investigate expression of ORFs in Enterococcus faecalis OG1RF genome. The arrays were designed based on the OG1RF annotation generated with the Rapid Annotation Using Subsystem Technology (RAST) server (Aziz et. al. 2008. BMC Genomics 9:75), as described in Frank et al (2012) Infect. Immun. 80:539. The aim was eighteen probe pairs per ORF, each of which is present in triplicate.