"Decision"-making in bacteria: chemotactic response of Escherichia coli to conflicting stimuli

Science. 1974 Jun 21;184(4143):1292-4. doi: 10.1126/science.184.4143.1292.


Motile bacteria presented simultaneously with both attractant and repellent respond to whichever one is present in the more effective concentration. Apparently bacteria have a processing mechanism that compares opposing signals from the chemoreceptors for positive and negative taxis, sums these signals up, and then communicates the sum to the flagella.

MeSH terms

  • Aspartic Acid
  • Chemotaxis*
  • Dose-Response Relationship, Drug
  • Escherichia coli / physiology*
  • Flagella / physiology
  • Membrane Potentials
  • Osmolar Concentration
  • Rotation
  • Valine


  • Aspartic Acid
  • Valine