Project description:Transcript abundance in Escherichia coli O157:H7 was determined in the presence or absence of pulsed expression of the small RNA, AsxR. AsxR was cloned under the control the arabinose inducible promoter Para. Escherichia coli O157:H7 str. TUV93-0 with pAsxR or empty vector was cultured in MEM-HEPES media to an OD600 of 0.8 and 0.2% arabinose added. 10min after addition of arabinose 10ml of cells were harvested and and pellets resuspended in 1ml of Trizol and total RNA isolated. RNAs were labelled using the SuperScript Plus indirect cDNA labelling System. Triplicate control RNAs were pooled and hybridised to seperate AsxR test RNAs on three microarays. Arrays were hybridised using the Maui hybridisation platform and Scann using and Axon Autoloader Scanner. GenePix software was used to analyse images and GPR files were analysed using Genespring 7.3.1.
Project description:Triclosan is a biocidal active agent commonly found in domestic cleaning products, hand sanitizers, cosmetics and personal care products. It is used to control microbial contamination and has a broad-spectrum of activity against many Gram-positive and Gram-negative bacteria. The development of triclosan tolerance with potential cross resistance to clinically relevant antibiotics in zoonotic pathogens is of concern given the widespread use of this active agent in clinical, food processing and domestic environments. Some studies have proposed that an over-dependence on triclosan-containing products could lead to the emergence of clinically important pathogens that are highly tolerant to both biocides and antibiotics. Currently, there is limited understanding of the mechanisms contributing to the emergence of triclosan tolerance in foodborne pathogens at a genetic level. We used microarray analysis to compare gene expression between a wildtype E. coli O157:H19 isolate (WT) with a minimum inhibitory concentration (MIC) to triclosan of 6.25 ug/ml and its laboratory generated triclosan tolerant mutant (M) with a MIC of >8000 ug/ml. Gene expression profiling was performed on untreated E. coli O157:H19 wildtype (WTu) and mutant (Mu), and on the wildtype and mutant treated with 6 ug/ml triclosan for 30 minutes (WTt and Mt respectively). RNA was extracted from three independent biological replicates for WTu, Mu, WTt & Mt for hybridization on Affymetrix GeneChip E. coli Genome 2.0 Arrays. Micorarray analysis including pre-processing, normalisation and statistical analysis were performed using R (R, 2007) version 2.6 and Bioconductor (Gentleman et al. 2004, Genome Biol. 5:R80) version 2.1 as previously described by Morris et al.(2009, Physiol. Genomics 39:28-37).
Project description:Diffuse outbreak investigation and development of rapid screening method by using whole genome sequences of enterohemorrhagic Escherichia coli O121
Project description:Transcript abundance in Escherichia coli O157:H7 was determined in the presence or absence of pulsed expression of the small RNA, AsxR.
Project description:Affymetrix Mouse Gene 1.0 ST Array profiles were generated from acticular cartilage derived from CBA and Str/ort mice at three ages (8W, 18W, 40W), corresponding to stages prior to, at and late after natural osteoarthritis (OA) onset in OA-prone Str/ort mice.
