TOKYO (AP) – Scientists have discovered the final case of regeneration: some beheaded sea slugs can make the heart and bodies grow completely new.
This “wonder of nature,” which was reported Monday in a biology journal, could help scientists better understand and cope with the regeneration of human tissue.
Biology researcher Sayaka Mitoh said she loved studying Japanese slugs because they are small, beautiful and weird. They can even do brief photosynthesizations like a plant pulling food out of the sun.
One day in the lab he saw something strange: a sea slug had been beheaded and his head was still moving and alive. Then a couple more did the same, according to a Current Biology study.
So the doctoral student and professor of aquatic ecology at Nara Women’s University, Yoichi Yusa, tried it themselves, cutting off the heads of 16 sea slugs. Six of the creatures began regeneration, and three were successful and survived. One of the three even lost and regained his body twice. Two different species of Japanese slugs did this regeneration trick.
Other creatures can expel body parts when needed, such as when some lizards drop their tails to move away from a predator, in a biological phenomenon called autotomy.
“We believe this is the most extreme case of autotomy,” Yusa said. “Some animals can self-automate their legs, appendages, or tails, but no other animal comes off the whole body.”
Scientists had thought that such a large animal (one of the species of sea slugs can grow up to 6 inches long) could not survive without a heart that pumps blood and nutrients to the brain, said Canadian marine biologist Susan Anthony. which was not part of the study.
But the same thing that makes this species spectacular is probably what helps it get its head out, Anthony and Yusa said.
When these sea slugs eat a certain type of algae, they can photosynthesize their food with sunlight and oxygen, just like a plant, for about 10 days, Yusa said. What probably happens after beheading is that the head acts like a plant, he said. It turns into a shade of green and gets its energy from oxygen and sunlight. The fact that it makes little help, he said.
Probably, these species developed the feat as a way to fight the parasites, said Mitoh and Yusa.
Several scientists said that humans could learn something useful from sea creatures. What’s especially interesting is that these sea slugs are more complex than flatworms or other species that know how to regenerate, said Nicholas Curtis, a biology professor at Ave Maria University who was not part of the study.
“Of course, it’s a marvel of nature, but understanding the underlying molecular mechanisms involved could help us understand how our cells and tissues can be used to repair damage,” Curtis said in an email.
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