Osmotaxis in Escherichia coli through changes in motor speed

Jerko Rosko, Vincent Martinez, Wilson Poon, Teuta Pilizota*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Bacterial motility, and in particular repulsion or attraction towards specific chemicals, has been a subject of investigation for over 100 years, resulting in detailed understanding of bacterial chemotaxis and the corresponding sensory network in many bacterial species. For Escherichia coli most of the current understanding comes from the experiments with low levels of chemotactically-active ligands. However, chemotactically-inactive chemical species at concentrations found in the human gastrointestinal tract produce significant changes in E. coli's osmotic pressure, and have been shown to lead to taxis. To understand how these nonspecific physical signals inuflence motility, we look at the response of individual bacterial agellar motors under step-wise changes in external osmolarity. We combine these measurements with a population swimming assay under the same conditions. Unlike for chemotactic response, a long term increase in swimming/motor speeds is observed, and in the motor rotational bias, both of which scale with the osmotic shock magnitude. We discuss how the speed changes we observe can lead to steady state bacterial accumulation.
Original languageEnglish
Pages (from-to)7969-7976
Number of pages8
JournalProceedings of the National Academy of Sciences
Volume114
Issue number38
Early online date5 Sep 2017
DOIs
Publication statusPublished - 19 Sep 2017

Keywords

  • Osmotaxis
  • bacterial agellar motor
  • single motor experiments
  • bacterial taxis
  • bacterial swimming

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