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Chemotaxis in Escherichia coli proceeds efficiently from different initial tumble frequencies
1Department of Biochemistry, University of California, Berkeley 94720.
Journal of Bacteriology
|February 1, 1990
Summary
Bacterial tumbling, a key part of chemotaxis, can be altered without affecting the ability of Escherichia coli to sense aspartate. This suggests the signaling system is robust to changes in tumbling levels.
Area of Science:
- Microbiology
- Cellular Biology
- Biophysics
Background:
- Chemotaxis enables bacteria to move towards attractants or away from repellents.
- Tumbling and flagellar motor regulation are crucial for bacterial chemotaxis in Escherichia coli.
Purpose of the Study:
- To investigate the relationship between tumbling frequency and chemotactic ability in Escherichia coli.
- To determine if altered tumbling levels impact chemotaxis towards aspartate.
Main Methods:
- Constructed two E. coli strains with modified tumbling levels using different aspartate receptor genes (wild-type and mutant Salmonella typhimurium receptor genes).
- Compared the chemotactic response and response times of these engineered strains with wild-type E. coli.
Main Results:
- Despite variations in adapted tumbling levels, all three E. coli strains exhibited similar response times and chemotactic ability toward aspartate.
- The study demonstrated that chemotaxis is maintained even when the absolute level of tumbling is modified, provided the signal processing system remains functional.
Conclusions:
- The bacterial signal processing system is adaptable, allowing for chemotaxis despite variations in tumbling frequency.
- Mutant strains with reduced tumbling may still effectively perform chemotaxis by increasing tumbling frequency in response to negative gradients.