Unknown,Transcriptomics,Genomics,Proteomics

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Transcriptional analysis of E. coli whole genome during heat inactivation processes related to industrial cooking

ABSTRACT: This study was conducted to determine the impact of extreme temperatures, aiming at controlling microorganisms by cooking, on the physiology and the transcriptome of Escherichia coli. ABSTRACT: Because the genome of Escherichia coli K12 is well understood, this organism was used as a model to investigate physiological and molecular changes during cell adaptation and survival to cooking temperatures used in the food industry. Bacteria grown at 37Â°C to stationary phase in Brain Heart Infusion (BHI) broth, were heated at 58Â°C or 60Â°C to reach a process lethality value (F) of 2 and 3, or until an internal core temperature of 71Â°C was reached (control cooking temperature). Both growth recovery and cell membrane integrity were evaluated immediately after heating and a global transcription analysis was performed by using gene expression microarrays. Only cells heated at 58Â°C F = 2 were still able to grow on liquid or solid BHI after heat treatment. However, their transcriptome did not differ significantly compared to those of bacteria heated at 58Â°C F = 3 (P-FDR > 0.01) where no growth recovery was observed post treatment. Genome-wide transcriptomic data obtained at 71Â°C were distinct from the other treatments. Quantification of heat-shock genes expression by real-time PCR revealed that dnaK and groEL mRNA levels were significantly lower at 71Â°C than at 58Â°C and 60Â°C (P < 0.0001). Furthermore, despite of similar cell inactivation but growth on BHI media after heating, 132 and 8 genes were differentially expressed at 71Â°C when compared to 58Â°C and 60Â°C at F = 3 respectively (P-FDR < 0.01). Among them, genes like aroA, citE, glyS, oppB and asd, whose expression was up-regulated at 71Â°C, may be considered as good biomarkers to determine more accurately the efficiency of heat treatments. Bacteria were submitted to four different heat-treatments. Biological replicates: 5 Controls grown to an optimal temperature of 37Â°C (and used to prepare a common reference for each array hybridization), 5 Treatment 1 (58Â°C F = 2), 4 Treatment 2 (58Â°C F = 3), 4 Treatment 3 (60Â°C F = 3), 5 Treatment 4 (core temperature of 71Â°C). Treatment replicates were randomly hybridized on 3 microarray slides Agilent 8x15K (total of 24 array areas). Equal amounts of the labeled control cDNA pool and labeled cDNA from one of the heated groups were mixed and hybridized on each array.

ORGANISM(S): Escherichia coli str. K-12 substr. MG1655

SUBMITTER: ANTHONY GUERNEC

PROVIDER: E-GEOD-40557 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Transcriptional analysis of E. coli whole genome during heat inactivation processes related to industrial cooking

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