Noise-Induced Increase of Sensitivity in Bacterial Chemotaxis

• Published in: Biophysical journal Vol. 111; no. 2; pp. 430 - 437
• Main Authors: He, Rui, Zhang, Rongjing, Yuan, Junhua
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 26.07.2016; Biophysical Society; The Biophysical Society
• Subjects: Biochemistry; Cell Biophysics; Cells; Cellular biology; Chemotaxis; E coli; Escherichia coli - cytology; Escherichia coli - genetics; Escherichia coli - metabolism; Methyl-Accepting Chemotaxis Proteins - genetics; Methyl-Accepting Chemotaxis Proteins - metabolism; Mutation; Signal transduction
• ISSN: 0006-3495; 1542-0086
• DOI: 10.1016/j.bpj.2016.06.013

Flagellated bacteria, like Escherichia coli, can swim toward beneficial environments by modulating the rotational direction of their flagellar motors through a chemotaxis signal transduction network. The noise of this network, the random fluctuation of the intracellular concentration of the signal protein CheY-P with time, has been identified in studies of single cell behavioral variability, and found to be important in coordination of multiple motors in a bacterium and in enhancement of bacterial drift velocity in chemical gradients. Here, by comparing the behavioral difference between motors of wild-type E. coli and mutants without signal noise, we measured the magnitude of this noise in wild-type cells, and found that the noise increases the sensitivity of the bacterial chemotaxis network downstream at the level of the flagellar motor. This provided a simple mechanism for the noise-induced enhancement of chemotactic drift, which we confirmed by simulating the E. coli chemotactic motion in various spatial profiles of chemo-attractant concentration.