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Marine bacterial chemoresponse to a stepwise chemoattractant stimulus
Li Xie1, Chunliang Lu2, Xiao-Lun Wu1
1Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania.
Biophysical Journal
|February 5, 2015
Summary
Marine bacteria Vibrio alginolyticus exhibit similar chemical signal processing during forward and backward swimming. However, the motor response differs, with forward swimming showing a twofold greater amplitude for weak stimuli.
Area of Science:
- Microbiology
- Biophysics
- Cellular Biology
Background:
- Polar flagellated marine bacteria like Vibrio alginolyticus display chemotaxis, moving towards chemical attractants.
- The coordination mechanism between forward and backward swimming intervals in response to chemical stimuli remains unclear.
Purpose of the Study:
- To determine the response functions of Vibrio alginolyticus to stepwise chemoattractant stimuli.
- To elucidate how the bacterium coordinates chemotaxis during forward and backward swimming.
Main Methods:
- Applying stepwise chemoattractant stimuli to Vibrio alginolyticus.
- Analyzing the bacterium's response functions during both forward and backward swimming intervals.
Main Results:
- Vibrio alginolyticus processes identical chemical signals similarly in both swimming directions.
- For weak stimuli, reaction and adaptation times are unchanged, but response amplitudes differ.
- The forward swimming interval exhibits approximately double the response amplitude compared to backward swimming.
Conclusions:
- Bacterial chemical signal processing is consistent across swimming directions.
- The flagellar motor's response to the chemotaxis network regulator (CheY-P) concentration is asymmetrical.
- This asymmetry in motor response likely has significant biological implications for marine bacteria.
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