The secret of the creature capable of stretching up to 30 times the length of its body

Certain single-celled protists are well known for their ability to make dynamic morphological changes in real time, including large transformations in cellular architecture. These organisms can withstand great mechanical stresses and enormous tensioning speeds to achieve these feats.

One of these single-celled protists, Lacrymaria olor, extends a neck-like protuberance to catch prey from a distance. This predator, which measures only 40 microns at rest, is capable of repeatedly stretching this protuberance to reach 1,200 microns in less than 30 seconds and subsequently retracting it just as quickly.

Until now, the underlying mechanisms that produce the extreme hyperextensibility of L. olor have been unknown.

To observe these mechanisms at the subcellular level, Eliott Flaum and Manu Prakash, both from Stanford University in California, United States, used a combination of live imaging, confocal microscopy and transmission electron microscopy.

They found that a layered cortical cytoskeleton and origami-like membrane architecture allow rapid extension and contraction of L. olor.

The discovery also reveals that the cell membrane retracts into 15 contiguous folds that, together, form a curved fold origami that can be sequentially unrolled to achieve rapid and repeatable hyperextensions of the neck.

This intricate folding scheme is built on a helical structure of microtubule filaments that guide membrane folds to ensure rapid and efficient unfolding and refolding during shape changes.

Example of the amazing capacity of the unicellular protist Lacrymaria olor. (Photo: Prakash Lab / Andrew Myers)

To better understand the dynamics involved, Flaum and Prakash developed a paper mechanical model that mimics the curved-fold origami architecture of L. olor.

These findings not only explain L. olor’s extreme ability to shapeshift, but also have the potential to inspire innovations in soft materials engineering or robotic system design.

The study is titled “Curved crease origami and topological singularities enable hyperextensibility of L. olor.” And it has been published in the academic journal Science. (Source: AAAS)