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Hydrogen peroxide effects on Streptococcus thermophilus CNRZ368 cell viability
A Thibessard1, A Fernandez, B Gintz
1Laboratoire de Génétique et Microbiologie, UMR INRA 1128, Faculté des sciences de l'Université Henri Poincaré Nancy I, Vandoeuvre-lès-Nancy, France.
Research in Microbiology
|August 15, 2001
Summary
Streptococcus thermophilus CNRZ368 possesses an inducible defense system against oxidative stress. Pre-exposure to low hydrogen peroxide levels enhances bacterial survival against higher concentrations, indicating a protective mechanism.
Area of Science:
- Microbiology
- Bacterial Physiology
- Oxidative Stress Response
Background:
- Streptococcus thermophilus CNRZ368 exhibits aerotolerance despite being an anaerobic bacterium.
- This characteristic suggests a potential defense mechanism against oxidative stress.
Purpose of the Study:
- To investigate the oxidative stress defense system in Streptococcus thermophilus CNRZ368.
- To determine the impact of hydrogen peroxide concentration on bacterial survival.
- To assess the influence of cellular physiological state and pre-exposure on survival.
Main Methods:
- Exposure of Streptococcus thermophilus CNRZ368 to varying concentrations of hydrogen peroxide.
- Evaluation of bacterial survival rates under different hydrogen peroxide conditions.
- Assessment of the effect of pre-exposure to sublethal hydrogen peroxide doses.
Main Results:
- Streptococcus thermophilus CNRZ368 survival is dependent on hydrogen peroxide concentration.
- Pre-exposure to sublethal hydrogen peroxide concentrations significantly enhances survival.
- The results indicate an inducible defense system against oxidative stress in this bacterium.
Conclusions:
- Streptococcus thermophilus CNRZ368 possesses a functional defense system against oxidative stress.
- This defense system is inducible, becoming more effective after prior exposure to oxidative agents.
- The findings contribute to understanding bacterial resilience in aerobic environments.