Tanscription profiling by array of E. coli upon cold shock from 35 degrees C to 14 degrees C for different periods of time

In a previous study we adopted an integrated transcriptomic and proteomic approach to determine the physiological response of E. coli O157:H7 Sakai during exponential phase growth under steady-state conditions relevant to low temperature and water activity conditions experienced during meat carcass chilling in cold air (Kocharunchitt et al., 2012). The findings of that study provide a baseline of knowledge of the physiology of this pathogen, with the response of E. coli O157:H7 to steady-state conditions of combined cold and osmotic stress. To provide an insight into the genetic systems enabling this organism to adapt to growth at low temperature, we extended the aforementioned study to investigate the growth kinetics of E. coli O157:H7 Sakai during abrupt temperature downshift from 35 degrees C to 14 degrees C and, examined time-dependent global alterations in its genome expression upon cold shock from 35 degrees C to 14 degrees C. The genome-wide expression response of E. coli was analysed by both cDNA microarray (transcriptome response) and 2D-LC/MS/MS analysis (proteome response). Differences in gene and protein expression patterns in E. coli before and after cold shock were analysed through quantitative and comparative analysis of time series changes in both mRNA and proteins levels.

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