Bacteria’s bodies do whirlies to help them swim

The trajectory of a bacterium's body follows a helical path and may generate thrust as the creature swims, new images and videos suggest.

Breuer Lab/Brown Univ.

Bacteria’s bodies were thought to be deadweight in the water. But new images and video show that the kidney-shaped Caulobacter crescentus swim with both their corkscrew-like propellers called flagella and their bodies. When the flagellum pushes a bacterium’s body, the cell whirls on a helical path, which can generate thrust and enhance the creatures’ movement, researchers report July 21 in the Proceedings of the National Academy of Sciences. The discovery may change the way scientists think about cell shape and its role in how bacteria swim in water and other fluids, such as mucus or semen.

Once a bacterium’s flagellum begins pushing it along, the bacterium swims in a helical path, as shown in this reconstruction. The second clip is shown at half speed. The axis bars represent micrometers.

Breuer Lab/Brown Univ.

Ashley Yeager is the associate news editor at Science News. She has worked at The Scientist, the Simons Foundation, Duke University and the W.M. Keck Observatory, and was the web producer for Science News from 2013 to 2015. She has a bachelor’s degree in journalism from the University of Tennessee, Knoxville, and a master’s degree in science writing from MIT.

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