title: Noise-Induced Increase of Sensitivity in Bacterial Chemotaxis.
abstract: 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.
authors.affiliation: Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui, China; Department of Physics, University of Science and Technology of China, Hefei, Anhui, China.
authors.forename: Rui
authors.initials: R
authors.lastname: He
authors.affiliation: Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui, China; Department of Physics, University of Science and Technology of China, Hefei, Anhui, China. Electronic address: rjzhang@ustc.edu.cn.
authors.forename: Rongjing
authors.initials: R
authors.lastname: Zhang
authors.affiliation: Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui, China; Department of Physics, University of Science and Technology of China, Hefei, Anhui, China. Electronic address: jhyuan@ustc.edu.cn.
authors.forename: Junhua
authors.initials: J
authors.lastname: Yuan
mesh_terms: D002633:Chemotaxis; D004926:Escherichia coli / Q000166:cytology* / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins; D000072236:Methyl-Accepting Chemotaxis Proteins / Q000235:genetics / Q000378:metabolism; D009154:Mutation
chemical_list: D029968:Escherichia coli Proteins; D000072236:Methyl-Accepting Chemotaxis Proteins; C000607606:cheY protein, E coli