TOKYO (Reuters) – Japanese researchers have shown that a type of sea slug is capable of self-decapitation and body growth, a discovery that could have ramifications for regenerative medicine.
The mechanism is believed to be an extreme method for the body to get rid of parasites, researchers Sayaka Mitoh and Yoichi Yusa wrote in a study published in Current Biology this week. Green slugs have algae cells on their skin, so they can feed on light like a plant until they develop a new body, which takes about 20 days.
Mitoh, a doctoral researcher at Nara Women’s University, realized one day that a sea slug, known as a sacoglosa, had spontaneously removed its head from its body.
“I was shocked and thought I was going to die, but he kept moving and eating a lot of energy,” Mitoh said. “I was watched for a while and he regenerated his heart and his body.”
This led to a study showing that five of the 15 laboratory breeding slugs and one from nature separated the body from a specific point on the neck during their lifetime. One did it twice. Each time, the animal’s heart remained in the body, which continued to live for a time, but did not grow any.
“One of the amazing things about stem cells is that they can be used to regenerate a heart and body from the edge of the animal’s head,” Mitoh said. “With a broader study, we may be able to apply these findings to regenerative medicine, but that is still a distant hope at this stage.”
Other animals have been known to intentionally shed and regenerate body parts, a mechanism known as autotomy, but this extreme form was not known before, the researchers said.
Initially they thought it could be a method to escape predators, but now they think it is done to get rid of parasites that inhibit reproduction.
Report by Rikako Murayama and Rocky Swift in Tokyo; Edited by Karishma Singh