Observation of magnetoreceptive behavior in a multicellular magnetotactic prokaryote in higher than geomagnetic fields

Biophys J. 2005 Feb;88(2):1496-9. doi: 10.1529/biophysj.104.047068. Epub 2004 Nov 19.


The magnetotactic multicellular prokaryote (MMP), a motile aggregate of bacterial cells, is known to exhibit an unusual "ping-pong" motility in magnetic fields greater than the earth's field. This motility is characterized by rapid excursions, opposite the direction of an applied magnetic field, and slower returns along the direction of the magnetic field. We have carried out detailed observations of the time and spatial dependence of the ping-pong motility and find 1), the outward and return excursions exhibit a uniform deceleration and acceleration, respectively; 2), the probability per unit time of an MMP undergoing a ping-pong excursion increases monotonically with the field strength; and 3), the outward excursions exhibit a very unusual distance distribution which is dependent on the magnetic field strength. At any given field strength, a characteristic distance is observed, below which very few excursions occur. Beyond this distance, there is a rapid increase in the number of excursions with an exponentially decaying distribution. These observations cannot be explained by conventional magnetotaxis, i.e., a physical directing torque on the organism, and suggest a magnetoreceptive capability of the MMP.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Background Radiation
  • Cell Movement / physiology*
  • Cell Movement / radiation effects*
  • Cells, Cultured
  • Dose-Response Relationship, Radiation
  • Electromagnetic Fields*
  • Ferric Compounds / metabolism
  • Ferric Compounds / radiation effects
  • Gram-Negative Bacteria / cytology
  • Gram-Negative Bacteria / physiology*
  • Gram-Negative Bacteria / radiation effects*
  • Radiation Dosage
  • Spheroids, Cellular / cytology
  • Spheroids, Cellular / physiology*
  • Spheroids, Cellular / radiation effects*


  • Ferric Compounds