Escherichia coli sentenced to death by heat stress : reaching out for the last functional genes

Authors: Guernec, AnthonyRobichaud-Rincon, PhilippeSaucier, Linda
Abstract: Escherichia coli K12 was used as a model to investigate physiological and molecular changes during cell adaptation and survival to cooking temperatures used in food industries. Bacteria grown to stationary phase in BHI broth were heated at 58°C or 60°C until a process lethality value (F70 10) of 2 or 3 was reached, or until an internal core temperature of 71°C was attained. Growth and cell integrity were evaluated after heating. Transcriptional modifications were analyzed by microarrays and expression of heat-shock genes was quantified by qPCR. Only cells heated at 58°C F=2 were still able to grow in liquid or on solid BHI after treatment. However, their transcriptome did not differ from those of bacteria heated at 58°C F=3 (PFDR > 0.01). Transcriptomic data obtained at 71°C were significantly different from the others. The expression of dnaK and groEL was significantly lower at 71°C than at 58°C and 60°C (P < 0.0001). Furthermore, despite similar cell viability and integrity post-treatment, 132 and 8 genes were differentially expressed at 58°C and 60°C F=3, respectively (P-FDR < 0.01) when compared to 71°C. These eight genes, whose expression was upregulated at 71°C, may be considered as good biomarkers to test antimicrobial efficiency of heatstress.
Document Type: Article dans une conférence
Issue Date: 13 August 2012
Open Access Date: 24 May 2019
Document version: AM
This document was published in: 58th International Congress of Meat Science and Technology : proceedings, 4 pages (2012)
Éditeur non identifié
Collection:Autres articles publiés

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