Tiny Organism Shrinks to a Quarter of Its Size in Milliseconds

The single-celled organism Spirostomum ambiguum contracts to a quarter of its length in under 5 ms, about 100 times faster than a human blink. Calcium ions trigger the contraction, driven by a fishing-net-like network of centrin and Sfi1 proteins. The finding could aid fast artificial muscles.

• Contraction to 25% of length takes under 5 ms
• Contraction speed is about 100 body lengths per second
• Calcium ions, not ATP as in muscles, trigger the movement
• Myoneme network of centrin and Sfi1 works like a fishing net