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Bacterial responses to alkaline stress.
Hiromi Saito1, Hiroshi Kobayashi
1Graduate School of Pharmaceutical Sciences, Chiba University, 1-8-1, Inohana, Chuo-ku, Chiba 260-8675, Japan.
Science Progress
|October 29, 2004
Summary
Bacterial adaptation to alkaline pH involves inducing genes with high-pH optimal activity. This response compensates for decreased enzyme function in alkalized cytoplasm, aiding survival in extreme environments.
Area of Science:
- Microbiology
- Molecular Biology
- Biochemistry
Background:
- Bacterial adaptation to alkaline pH is less studied than acidic pH adaptation.
- Global gene expression analysis reveals numerous gene inductions at high pH.
Purpose of the Study:
- Investigate the necessity of numerous genes for bacterial adaptation to alkaline pH.
- Propose a mechanism for gene induction under alkaline stress.
Main Methods:
- Analysis of global gene expression data under various conditions.
- Review of existing literature on internal bacterial pH and enzyme activity at high pH.
Main Results:
- Cytoplasmic pH increases with medium alkalization, though less than external pH change.
- Enzyme activities optimized for neutral pH may decrease under alkaline conditions.
- Numerous genes are induced in bacteria exposed to high pH environments.
Conclusions:
- Genes induced under alkaline stress likely encode products with optimal activity at high pH.
- This induction compensates for the reduced activity of neutral pH-dependent systems.
- The findings provide insight into bacterial survival strategies in alkaline environments.