Escherichia coli heat shock protein DnaK : production and consequences in terms of monitoring cooking

Auteur(s): Seyer, Karine; Lessard, Martin; Piette, Gabriel; Lacroix, MoniqueSaucier, Linda
Résumé: Through use of commercially available DnaK proteins and anti-DnaK monoclonal antibodies, a competitive enzyme-linked immunosorbent assay was developed to quantify this heat shock protein in Escherichia coli ATCC 25922 subjected to various heating regimens. For a given process lethality (F10/70 of 1, 3, and 5 min), the intracellular concentration of DnaK in E. coli varied with the heating temperature (50 or 55°C). In fact, the highest DnaK concentrations were found after treatments at the lower temperature (50°C) applied for a longer time. Residual DnaK after heating was found to be necessary for cell recovery, and additional DnaK was produced during the recovery process. Overall, higher intracellular concentrations of DnaK tended to enhance cell resistance to a subsequent lethal stress. Indeed, E. coli cells that had undergone a sublethal heat shock (105 min at 55°C, F10/70 = 3 min) accompanied by a 12-h recovery (containing 76,786 +- 25,230 molecules/cell) resisted better than exponentially growing cells (38,500 +- 6,056 molecules/cell) when later heated to 60°C for 50 min (F10/70 = 5 min). Results reported here suggest that using stress protein to determine cell adaptation and survival, rather than cell counts alone, may lead to more efficient heat treatment.
Type de document: Article de recherche
Date de publication: 1 juin 2003
Date de la mise en libre accès: Accès restreint
Version du document: VoR
Lien permanent:
Ce document a été publié dans: Applied and environmental microbiology, Vol. 69 (6), 3231-3237 (2003)
American Society for Microbiology
Autre version disponible: 10.1128/AEM.69.6.3231-3237.2003
Collection :Articles publiés dans des revues avec comité de lecture

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