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Characterization of the heat shock response in Enterococcus faecalis
P Boutibonnes1, J C Giard, A Hartke
1Laboratory of Microbial Genetics, University of Caen, France.
Antonie Van Leeuwenhoek
|January 1, 1993
Summary
Enterococcus faecalis exhibits enhanced heat and ethanol tolerance after prior heat shock exposure. This response involves the synthesis of specific heat shock proteins, including those related to E. coli DnaK and GroEL.
Area of Science:
- Microbiology
- Bacterial Physiology
- Stress Response
Background:
- Enterococcus faecalis is a Gram-positive bacterium known for its hardiness.
- Understanding its stress response mechanisms is crucial for predicting its behavior in various environments.
Purpose of the Study:
- To characterize the heat shock response in Enterococcus faecalis.
- To investigate the induction of thermotolerance and ethanol tolerance.
- To identify the heat shock proteins synthesized during this response.
Main Methods:
- Exposure of log phase E. faecalis cells to prior heat shock (45°C or 50°C).
- Assessment of heat resistance at elevated temperatures (60°C or 62.5°C).
- Analysis of heat shock protein synthesis using Western blot, comparing to E. coli and B. subtilis proteins.
Main Results:
- Prior heat shock significantly enhanced heat resistance and induced ethanol tolerance.
- Thermotolerance onset correlated with the synthesis of heat shock proteins (48–94 kDa).
- Identified proteins immunologically related to E. coli DnaK and GroEL, and other E. coli/B. subtilis proteins.
Conclusions:
- Enterococcus faecalis mounts a protective heat shock response involving thermotolerance and ethanol tolerance.
- Specific heat shock proteins, including homologs of DnaK and GroEL, are key components of this response.
- Ethanol stress also elicits a similar, though weaker, heat shock protein induction.