The single-celled organism Lacrymaria olor employs one of the strangest predation techniques. Its oval body measures about 40 micrometers and has a protruding neck at the end. When food is detected, it can extend this “neck” about 30 times its body length in just a few seconds to capture prey from a distance, an action that makes it resemble the Loch Ness Monster.
Lacrymaria olor extends its neck about 20,000 times throughout its life without any incidents.
But how can L. olor achieve this without tearing its cell membrane? Recently, this question was answered by Eliott Flaum and Manu Prakash from Stanford University, USA.
They reported their research findings in the journal Science, stating that the cell membrane and internal structure of this single-celled organism are folded in a way similar to origami, allowing it to be easily extended and retracted.
This means that the forces acting on the membrane require very low energy, the researchers wrote, with L. olor being able to extend its neck about 20,000 times throughout its life without any incidents.
The unusual predation technique of this tiny organism raises a host of potential issues. Typically, a significant amount of energy is needed to deform a cell membrane, and given the speed at which L. olor extends its neck, the organism would be unable to produce enough new membrane material. Furthermore, while the neck must be extremely flexible to move quickly, it also needs to be rigid and stable enough to avoid breaking at the first stretch. L. olor addresses all these challenges by folding its neck membrane into multiple layers.
The folds of the membrane have a complex curved geometry that allows it to unfurl into a cylindrical shape. Beneath the folded membrane is a network of coiled tubes that are also folded along with the membrane, facilitating orderly extension and retraction. This principle is similar to the so-called Yoshimura origami folding, where a cylinder consists of a network of folded rhombuses that can quickly extend and fold back.
