title: Extremely rapid acclimation of Escherichia coli to high temperature over a few generations of a fed-batch culture during slow warming.
abstract: This study aimed to demonstrate that adequate slow heating rate allows two strains of Escherichia coli rapid acclimation to higher temperature than upper growth and survival limits known to be strain-dependent. A laboratory (K12-TG1) and an environmental (DPD3084) strain of E. coli were subjected to rapid (few seconds) or slow warming (1°C 12 h(-1)) in order to (re)evaluate upper survival and growth limits. The slow warming was applied from the ancestral temperature 37°C to total cell death 46-54°C: about 30 generations were propagated. Upper survival and growth limits for rapid warming (46°C) were lower than for slow warming (46-54°C). The thermal limit of survival for slow warming was higher for DPD3084 (50-54°C). Further experiments conducted on DPD3084, showed that mechanisms involved in this type of thermotolerance were abolished by a following cooling step to 37°C, which allowed to imply reversible mechanisms as acclimation ones. Acquisition of acclimation mechanisms was related to physical properties of the plasma membrane but was not inhibited by unavoidable appearance of aggregated proteins. In conclusion, E.coli could be rapidly acclimated within few generations over thermal limits described in the literature. Such a study led us to propose that rapid acclimation may give supplementary time to the species to acquire a stable adaptation through a random mutation.
authors.affiliation: UMR A 02.102 Procédés Alimentaires et Microbiologiques, Equipe Procédés Microbiologiques et Biotechnologiques, AgroSup Dijon, Université de Bourgogne, 1 Esplanade Erasme, 21000, Dijon, France.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Guyot
authors.forename: Laurence
authors.initials: L
authors.lastname: Pottier
authors.forename: Alain
authors.initials: A
authors.lastname: Hartmann
authors.forename: Mélanie
authors.initials: M
authors.lastname: Ragon
authors.forename: Julia
authors.initials: J
authors.lastname: Hauck Tiburski
authors.forename: Paul
authors.initials: P
authors.lastname: Molin
authors.forename: Eric
authors.initials: E
authors.lastname: Ferret
authors.forename: Patrick
authors.initials: P
authors.lastname: Gervais
mesh_terms: D000064:Acclimatization / Q000502:physiology*; D058491:Bacterial Load; D001431:Bacteriological Techniques; D061249:Batch Cell Culture Techniques; D004926:Escherichia coli / Q000235:genetics / Q000502:physiology* / Q000648:ultrastructure; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000502:physiology; D006358:Hot Temperature; D008560:Membrane Fluidity; D017433:Protein Structure, Secondary
chemical_list: D029968:Escherichia coli Proteins
keywords: Acclimation; Escherichia coli; slow warming; thermal niche