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:The microarrays experiments was performed in order to identify transcriptional networks in Enterococcus faecalis. Work:Reduced glutathione levels in Enterococcus faecalis trigger metabolic and transcriptional compensatory adjustments during iron exposure
Project description:Enterococcus faecalis is a natural inhabitant of the human gastrointestinal tract. In a healthy physiological state of the gut (eubiosis), E. faecalis is a subdominant species in the intestinal microbiota. When the intestinal homeostasis is disrupted (dysbiosis), it becomes dominant species and can cause infections. The taurocholate bile acid (TCA) becomes prominent during dysbiosis. This experiment aimed to better understand how E. faecalis adapts to TCA. We showed that TCA reprograms genes involved in the pool management of amino acids and nucleotides.
Project description:Small non coding RNA molecules (sncRNAs) are key mediators of virulence and stress inducible gene expressions in some pathogens. In this work we identify sncRNAs in the Gram positive opportunistic pathogen Enterococcus faecalis. Enterococcus faecalis. We characterized 11 sncRNAs by tiling microarray analysis, 5’ and 3’ RACE-PCR, and Northern blot analysis. Six sncRNAs were specifically expressed at exponential phase, two sncRNAs were observed at stationary phase, and three were detected during both phases. This is the first experimental genome-wide identification of sncRNAs in E. faecalis and provides impetus to the understanding of gene regulation in this important human pathogen.
Project description:CroRS is a cell envelope stress response two-component system in the bacterial pathogen Enterococcus faecalis. Antimicrobial tolerance is the ability of an organism to survive, but not proliferate, upon antimicrobial challenge, and is a known precursor to the development of antimicrobial resistance. We have previously shown that CroRS is essential for antimicrobial tolerance in E. faecalis. Therefore, the aim of this experiment was to determine the teixobactin-induced CroRS regulon to identify key pathways of antimicrobial tolerance. To do this, E. faecalis wild-type and a croRS deletion mutant were grown to mid-exponential phase and challenged with and without teixobactin (0.5 ug/ml) for 1 hour. RNA was subsequently extracted, purified and RNA sequenced. RNA libraries were prepped using the Zymo-Seq RiboFree Total RNA-Seq Library Kit. Sequencing was completed using an Illumina MiSeq (v3) system generating 150 bp paired-end reads.
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.
Project description:Enterococcus faecalis, a member of the human gastrointestinal microbiota, is a Gram-positive, opportunistic pathogen associated with hospital-acquired wound, bloodstream, and urinary tract infections. E. faecalis can suppress or evade immune-mediated clearance by macrophages to promote persistent infection, although the exact mechanisms and bacterial factor(s) involved are not well-defined. In this study, we examined E. faecalis factor(s) involved in suppressing macrophage activation, as well the macrophage pathways modulated by E. faecalis to suppress activation. We observed that E. faecalis prevents ERK and p65 phosphorylation and reduces MyD88 expression leading to a reduction in NF-κB activity. We identified E. faecalis lactate dehydrogenase, which is important for lactic acid production by E. faecalis, to be necessary for macrophage suppression and demonstrated that E. faecalis lactate dehydrogenase-mediated immune suppression promotes E. coli survival during polymicrobial wound infection. Taken together, these results suggest that that E. faecalis-derived lactic acid is involved in macrophage subversion and may help to promote the virulence of co-infecting bacteria.
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).