Project description:Teixobactin is the first novel antimicrobial to be discovered in decades and represents a new class of antimicrobials. Teixobactin shows great promise with proven efficacy against multi-drug resistant organisms such as methicillin-resistant S. aureus (MRSA), vancomycin-resistant Enterococci (VRE), and Mycobacterium tuberculosis. VRE infections are notoriously difficult to treat with complex and adaptable cell wall stress response systems, which confer intrinsic resistance to a wide variety of antimicrobials. The aim of this study was to isolate the teixobactin-induced transcriptional response by challenging lab strain Enterococcus faecalis JH2-2 with sub-MIC levels of teixobactin using RNA sequencing. Two cultures of E. faecalis were grown to an OD600 of 0.2 and subsequently split into three to form a total of six cultures (two samples, with three technical replicates each), and grown to an OD600 of 0.5. One set of three cultures were treated with 0.5 ug/ml (0.25 x MIC), and all six cultures were grown for a further 1h. Cells were harvested by centrifugation and stored at -80 degrees C. RNA was extracted using TRIzol-chloroform and RNA samples were run through the RNAeasy Minikit (Qiagen). The Agilent RNA 6000 Nano kit and the Agilent 2100 Bioanalyzer (RIN >8), was used to verify RNA quality as per the manufacturer’s instructions, and RNA concentration was determined using a NanoDrop ND-100 spectrophotometer. Ribosomal RNA was removed from total RNA using Ribo-Zero and cDNA libraries were created using the Illumina TruSeq™ stranded total RNA library prep kit. Sequencing was completed using Illumina MiSeq_v3 generating 150 bp single end reads. Adapter sequences were removed from raw fastq files using Flexbar and reads shorter than 50bp were discarded. Sequence reads from each sample were mapped against the E. faecalis JH2-2 genome (NZ_KI518257.1) using Bowtie to produce a table of raw read counts for JH2-2 genes for each of the replicates. Statistical and principal component analysis were performed using the Bioconductor DESeq package.
Project description:The vancomycin resistant strain V583 was exposed to therapeutical dose of vancomycin in order to understand the cell response to the antibiotic besides the induction of the vanB genes
Project description:Transcriptional profiling to investigate the effect of drug treatment on the E. faecalis cells. For microarray analysis, E. faecalis OG1RF was grown in FMC medium supplemented with 10 mM glucose to an optical density at 600 nm (OD600) of 0.3 and the cultures were divided in 3 aliquots. One aliquot was collected by centrifugation and immediately frozen (untreated control cells). The other aliquots were treated for 30 or 60 min with 1.25 X the minimum inhibitory concentration (MIC) of vancomycin (10 M-NM-<g ml-1). After an exposure time of 30 or 60 minutes, each of these cultures was also centrifuged and the pellets frozen. RNA was then isolated from each pellet for microarray analysis. This process was repeated 3 additional times, for a total of four replicates of each condition. RNA was extracted from four replicate samples of each condition of interest (control cells grown to OD600 = 0.3 in FMC medium supplemented with 10mM glucose, then treated with vancomycin for 30 or 60 minutes) and labeled with Cy3. For each replicate, labeled RNA was hybridized to slides along with Cy5-labeled reference RNA, extracted from E. faecalis OG1RF cells grown in BHI medium to mid-log.
Project description:The enterococci comprise a genus of 49 low-GC content Gram-positive commensal species within the Firmicutes phylum that are known to occupy diverse habitats, notably the gastrointestinal core microbiota of nearly every phylum, including human. Of particular clinical relevance are two rogue species of enterococci, Enterococcus faecalis and the distantly related Enterococcus faecium, standing among the nefarious multi-drug resistant and hospital-acquired pathogens. Despite increasing evidence for RNA-based regulation in the enterococci, including regulation of virulence factors, their transcriptome structure and arsenal of regulatory small sRNAs (sRNAs) are not thoroughly understood. Using dRNA-seq, we have mapped at single-nucleotide resolution the primary transcriptomes of E. faecalis V583 and E. faecium AUS0004. We identified 2517 and 2771 transcription start sites (TSS) in E. faecalis and E. faecium, respectively. Based on the identified TSS, we created a global map of s70 promoter motifs. We also revealed features of 5’ and 3’UTRs across the genomes. The transcriptome maps also predicted 150 and 128 sRNA candidates in E. faecalis and E. faecium, respectively, some of which have been identified in previous studies and many of which are new. Finally, we validated several of the predicted sRNAs by Northern Blot in biologically relevant conditions. Comprehensive TSS mapping of two representative strains will provide a valuable resource for the continued development of RNA biology in the Enterococci.