Effect of gamma radiation on heat shock protein expression of four foodborne pathogens.
OBJECTIVE
The effects of gamma radiation on three heat shock proteins (Hsps) (GroEL, DnaK and GroES) synthesis in two Gram-negative (Escherichia coli and Salmonella serotype Typhimurium) and two Gram-positive (Staphylococcus aureus and Listeria monocytogenes) bacteria were investigated.


RESULTS
The bacterial strains were treated with three radiation doses to induce cell damage, to obtain a viable but nonculturable state, and to cause cell death. Western blot analysis and quantification of Hsps in bacteria were performed immediately after irradiation treatment. In the four foodborne pathogens, GroEL was strongly induced by gamma rays in a dose-dependent manner, confirming the involvement of this protein in the cellular response to the stress generated by ionizing radiation. In addition, it was found that E. coli exposed to gamma radiation showed a significantly induction of DnaK and GroES proteins when compared with nonirradiated bacteria, whereas a GroES slight induction and a DnaK inhibition were observed in Salm. Typhimurium.


CONCLUSIONS
The gamma rays influence the synthesis of Hsps in foodborne pathogen in a way that critically depends on the radiation dose.


CONCLUSIONS
The study of stress response to several radiation doses was undertaken to elucidate how bacteria can survive in harsh conditions and cope with gamma radiation used to control foodborne pathogens and to characterize their adaptative response to this treatment.
Caillet
S
S
Canadian Irradiation Center and Research Laboratories in Sciences Applied to Food, INRS-Institut Armand-Frappier, Laval, QC, Canada.
Millette
M
M
Dussault
D
D
Shareck
F
F
Lacroix
M
M
D015153:Blotting, Western; D018835:Chaperonin 10 / Q000378:metabolism / Q000528:radiation effects; D018834:Chaperonin 60 / Q000378:metabolism / Q000528:radiation effects; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000378:metabolism* / Q000528:radiation effects*; D029968:Escherichia coli Proteins / Q000378:metabolism* / Q000528:radiation effects*; D005720:Gamma Rays; D006360:Heat-Shock Proteins / Q000378:metabolism*; D008089:Listeria monocytogenes / Q000378:metabolism* / Q000528:radiation effects*; D012486:Salmonella typhimurium / Q000378:metabolism* / Q000528:radiation effects*; D013211:Staphylococcus aureus / Q000378:metabolism* / Q000528:radiation effects*
D018835:Chaperonin 10; D018834:Chaperonin 60; D029968:Escherichia coli Proteins; D006360:Heat-Shock Proteins