A shimmering sea creature called a comb jelly has amazing abilities. Even when injured, the two can fuse into one without exhibiting the tissue rejection seen in other animals. Additionally, the two animals’ nervous systems are integrated and their digestive tracts fuse to share food.
The discovery could help scientists investigate how the immune system evolved the ability to distinguish an organism’s own tissues from those of another organism and gain insight into the evolution of the nervous system. be.
Despite their name, comb jellies or ctenophores are not jellyfish. Their bodies are fundamentally different. They are the oldest living creatures to have diverged from the common ancestor of all animals, and their unusual ecology makes them a fascinating subject for scientists studying early animal evolution. For example, rather than having individual nerve cells like other animals, they have a unique nervous system consisting of nerve cells that combine to form a continuous network.
Kei Shirokura of the University of Exeter, UK, Mnemiopsis leidii when he noticed an unusually large specimen. It had two posterior ends and two sensory organs known as apical organs, as if the two were somehow connected.
To test this idea, he and his colleagues cut pieces of individuals collected from different locations on different days, meaning they were unrelated to each other, and arranged them as pairs. In nine out of 10 cases, the two bodies seamlessly merged into one within a few hours. “I was very surprised,” says Shirokura.
Unlike the norm in most other animals, one body did not reject foreign tissue from the other, so the immune system of ctenophores had a combination of “self” and ” This suggests that they lack the ability to distinguish between “non-self”.
When the researchers gently poked one lobe, the entire fused body responded as one, contracting its muscles in synchrony, suggesting that the two nervous systems had also completely fused. The gastrointestinal tract was also fused. When the team fed food into only one mouth, the food entered the combined digestive tract.
“This is an interesting first discovery,” says Pavel Burkhardt of the University of Bergen in Norway. “It opens up many new questions that can be studied.” These could include when animals evolved heterogeneous cognition and how neural networks form and process information.
These aren’t the only questions that ctenophores might be able to answer. Burkhardt and his team have recently discovered that when starved or injured, Mnemiopsis leidii Individuals can reverse growth, going from an adult stage back to a larval-like stage and then back again. Until now, the only known example of an animal with similar abilities is the so-called immortal jellyfish (Turritopsis dohrnii) And a type of tapeworm.
The discovery that ctenophores can also do this means it may have been a feature of the last common ancestor of all animals and is more widespread among animals than previously thought. suggests that it is possible. “What I personally find very interesting is that this may mean that the first animals were more plastic and more adaptable,” Burkhardt says.
These enigmatic, shimmering animals are shaping up as keys to understanding a series of fundamental biological processes, some of which are related to human health, including tissue rejection, regeneration, and aging. There may be. “This is definitely a very valuable model for tackling some of these big problems,” Burkhardt says.
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(Tag translation) Animal
