Cells in complex organisms sometimes respond to pressure and stress by growing in a preferred direction. The phenomenon, called mechanotaxis, helps create multicellular structures such as our organs.

Now a common soil bacterium has been found to change its growth pattern in response to disturbances in its environment. And the discovery could provide a living system for testing strain in materials under heavy loads—like, say, bridges.

The bacterium in question is called Bacillus mycoides. It was first characterized way back in 1842. Much more recently, researchers in the U.K. noticed that the Bacillus had unique growth patterns on solid cultures that contained structural defects.

The scientists took a series of microscope photos of bacterial cultures on templates with a variety of defects and under different pressures. And the bacterial filaments turned a full 90 degrees in response to only 1 degree of structural distortion. The bacteria also grew towards a glass bead disturbing the culture. The research is in the journal PLoS One. [James P. Stratford, Michael A. Woodley and Simon Park, Variation in the Morphology of Bacillus mycoides Due to Applied Force and Substrate Structure]

If this technique can be better understood and manipulated, scientists might be able to develop a bacterial early warning system for our engineered environment. A big help from a small creature.

—Cynthia Graber

[The above text is a transcript of this podcast.]