Project description:This research focuses on the design, manufacturing and validation of a new E. coli whole-genome tiling micraorray platform for novel RNA transcript discovery. A whole-genome tiling microarray allows both annotated genes as well as previously unknown RNA transcripts to be detected and quantified at once. The E. coli MG1655 genome is re-acquired with next-generation sequencing and then used to design the tiling microarray with the thermodynamic analysis program Picky. Validations are performed by subjecting E. coli under various growth conditions and then using the tiling microarrays to verify expected gene expression patterns.
Project description:Protein expression by E. coli 26561 during the late-exponential phase of cultures under anaerobic conditions was examined. E. coli 26561 is a multidrug resistant (MDR) and shows an unusual hyper-mucoviscous phenotype. Resistance includes ESBL (CTX-M-14) and proteome was determined with and without exposure to sub-MIC concentrations of the 3rd generation cephalosporin ceftazidime. Ceftazidime exposure was at two sub-MIC levels, specifically 0.25x MIC (samples 5-7), 0.5x MIC (samples 8 - 10); samples 1-4 provided the unexposed Control. Both whole and phospho-enriched fractions for each sample were analysed. Quantification of peptides was assessed using 10-plex TMT labelling in conjunction with an Orbitrap Fusion Tribrid. Raw data produced by the Orbitrap were processed using Max Quant 1.5.4.7 using the included Andromeda search engine. Peptides were searched against our own database of E. coli 26561 proteins which was produced from a hybrid assembly of our reads obtained from MiSeq and PacBio sequencing platforms.
Project description:Extraintestinal pathogenic Escherichia coli (ExPEC) is a common bacterial strain causing diverse diseases in humans and animals. To analyse the detailed mechanisms underlying ExPEC-mediated sepsis in humans, the transcriptome response of mice at 3h,6h, and 12h after ExPEC infection was analyzed by RNA-seq of mouse spleen samples.
Project description:To characterize the differentially expressed genes between pathogenic avian E. coli and human E. coli ATCC 25922, Abstract Escherichia coli (E. coli) is a harmless common bacterium of poultry intestine, but with a wide range of genomic flexibility, is also causative agent of many poultry diseases collectively called colibacillosis that is blamed for high economic loss in poultry sector worldwide. Numerous studies have been conducted to check the prevalence of pathogenic E. coli in poultry and poultry products, however limited data are available regarding their resistance and virulence associated genes expression profile. This study examined the pathogenomic content of poultry E. coli by antibiotic susceptibility, biofilm formation and adhesion, invasion and intracellular survivability assays in Caco-2 and Raw 264.7 cell lines along with the determination of median lethal dose in two-day old chickens. A clinical pathogenic multidrug resistant (MDR) isolate, E. coli 381, isolated from broilers was found to be highly virulent in cell culture and in chicken model. Transcriptome analysis has been skewed towards bacterial pathogens because of the prioritization of poultry diseases. Comparative gene expression profile of MDR E. coli 381 and the reference human strain E. coli ATCC 25922 was done using Illumina HiSeq2500 transcriptome and results were verified by RT-qPCR analyses. A number of resistant encoding genes including multidrug transporters, multidrug resistance proteins, porins and autotransporters were identified. We also noticed overexpression of very important virulent genes (fimA, fimC, fimH and fimI) encoding the type-1 fimbrial proteins, curli fimbriae genes , invasin genes, toxin-encoding genes and biofilm forming regulatory genes . In addition, many types of stress and metal homeostasis controlling genes were among up-regulated genes in E. coli 381 as compared to reference strain. GO and KEGG pathway analysis results revealed that genes controlling secondary metabolism, drug transport, adhesion and invasion proteins, and mobile genetic elements were over-expressed in E. coli 381. Several genes involved in cellular and metabolic processes such as carbohydrate metabolism were responsible for stress tolerance. Seminal description of the transcriptomic results and other unique features of E. coli 381 confirmed that it is highly virulent and MDR strain of poultry origin. This comparative study provides new avenues for further work on molecular mechanisms to prevent resistance development in bacteria and to ensure public health.
Project description:Counting DNA reads using whole genome sequencing is providing new insight into DNA double-strand break repair (DSBR) in the model organism Escherichia coli. We describe the application of RecA chromatin immunoprecipitation coupled to genomic DNA sequencing (RecA-ChIP-seq) and marker frequency analysis (MFA) to analyse the genomic consequences of DSBR.