The tiny, single-celled creatures are unable to use their brains to teach them how to move in complicated ways. They usually roll, slither, or swim to get around.
Microscopic pond dwellers were called Euplotes eurystomus have mastered a way to walk brainlessly – scurrying about like insects, with their 14 little appendages.
They look a lot like the Dutch-designed, kinetic sculptures called StrandbeastsThey are connected by clockwork-like connections that cycle them through a series of set states, which can be altered in response to their environment.
“There seemed to have been this sequential logic occurring with the movements.” “Ben Larson, a biophysicist from the University of California, San Francisco. “They were not random. We began to suspect some information processing was occurring.”
These protozoans – single-celled organisms with animal-like characteristics – have 14 stingy bundles of cilia that work together as legs called cirri. These cirri allow them to walk and swim while actively hunting prey.
All this started in 2016 @MBLPhysCourse during my PhD @Choano_Lab. I had observed predatory critters eating the Choanoflagellates I was trying out from field samples. I knew Wallace was an expert in crazy microorganisms so we had a great conversation.
2/n pic.twitter.com/R4jRwOAWhQ
— Ben Larson (@BEuplotes) March 1, 2021
Larson and his colleagues took microscopic footage to observe the movements of these tiny predators in slow motion. Researchers discovered 32 combinations of leg movements that were most likely to match each other.
Tubulin fibers make up the cirri, which are similar to the rest of the cell’s scaffolding structures (its Cytoskeleton). These fibers act as support structures between different cirri and can also be used to communicate mechanically.
“EuplotesUses these connections to allow for a more elaborate walking motion. explainsWallace Marshall, UCSF biophysicist.
Computer modeling demonstrated that tension and strain on fibers dictated the cirri positions possible at any moment. Some cirri hold stress at different stages in a gait. When that stress is released, it propels cells to the next state. This creates a cyclic transition.
“The fact that EuplotesAppendages move from one state to the next in a non-random manner, which means that this system works like a rudimentary computing device.” “ Marshall.
The researchers were exposed EuplotesA drug that interrupts the synchronous reaction of the tubulin fibres caused the cell’s gait to be disrupted, leading to the poor animals to walk in futile circles.
Although their gait was still regular, it wasn’t coordinated in a way that enabled them to move effectively. The clockwork connections between appendages couldn’t be wound up or reset to keep the cell ticking forwards.
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These single-celled organisms are not controlled by brains or nerves but rather by networks of signaling molecules. As we’ve seen, such systems can produce complex behaviors in microbes. decision-makingLearning, and Navigating mazes.
“This is an amazing biological phenomenon that could be used to highlight general computational processes in other types cells.” “ Larson.
We still have much to know about the mechanism of this locomotive system. But, now we can add walking as an example of how random molecular reactions can be harnessed in order to create sequential behaviors.
This research was published in Current Biology.
