Tiny brainless single-celled organisms can also make complex “decisions”

Tiny brainless single cell clusters can make decisions that can “change their minds” and avoid exposure to irritating substances, according to a new study. More than a century ago, American zoologist Herbert Spencer Jennings tested a relatively large, horn-shaped single-celled organism called Stentor roeselii, and found that when he released a pungent sebum powder around these single-celled organisms, Single cells were observed to react in a predictable pattern. He described the behavioral characteristics of single cells in his 1906 study, Low Biological Behavior.

When the surface of a single-celled organism, Stentor roeselii, comes into contact with certain substances, it rapidly shrinks to get rid of them.

Stentor roeselii first tries to avoid the powder around the body if the measure does not work; they reverse the cilia movement and push away the surrounding particles, whose cilia is a hair-like protrusion that moves and eats; if neither of these conditions is effective, the single-celled organism will shrink rapidly, and eventually if all methods fail. It will shed the surface debris and move quickly.

In the decades that followed, scientists failed to replicate the findings in a number of experiments, and the discovery was questioned, and a team of researchers at Harvard University recently decided to do the old experiment again, and study author Jeremy Gunawadna, a Harvard university system student, decided to do it again. ‘It’s a “skunk test” that is completely out of the textbook, and it’s not a daily job that anyone can do,’ Gunawardena said in a statement.

After a long search, the researchers obtained samples from a British supplier from a golf course, and the ship was transported to a laboratory in Gunawadna, where the team used a microscope to observe and record the behavioral responses of these single-celled organisms when they encountered nearby stimuli.

First, they tried to release the irritating carptoe powder, a 21st-century single-celled organism that was less likely to be disturbed than its ancestors more than 100 years ago, and the study showed that the sebum powder was a natural product of the carptoid, so the composition of the carphees may have changed since the Jennings era, so the researchers tried to use another stimulant, the slugs. Micro grade plastic ball.

At this point, the results were in line with previous expectations, and Stentor Roeselii began to try to avoid plastic balls, using a strategy consistent with the Jennings study, and at first their evasive behavior did not show any specific patterns, such as that some single-celled organisms bent the body and contracted, while others only contracted. Statistical analysis by scientists shows that, on average, single-celled organisms often make decisions with similar patterns of behavior – almost always choosing to bend and change the direction of their cilia before shrinking or wandering.

What’s more, the researchers found that if single-celled organisms did reach a stage where contraction or separation was needed, the probability of choosing one of these behaviors was equal.

“They’re going to do simple defenses first, and if they’re constantly excited, they’ll ‘decide’ to try other methods, and Stentor Roeselii doesn’t have a brain, but there seems to be a mechanism that ‘changes their mind’ once the stimulus lasts too long,” Gunawadnadner said. “

The findings could help scientists develop cancer research and even change our perception of our own cells, Gunwadnadner said. “Cells are not just genetically programmed to do the task, they exist in a very complex ecosystem that communicates and coordinates with each other to some extent, reacts to signals and decisions. The ancestors of single-celled organisms once ruled the ancient Earth, and it is likely that they are more complex than people know. “The latest study is now published in the December 5 issue of the journal Current Biology.