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The ability for a jellyfish to regenerate body parts is often considered its ‘superpower’, but now researchers have found what’s behind it.
Much mystery surrounds marine creatures in general, but jellyfish are among the most difficult to research. While a lot has been learned about these creatures in recent years, very little is known about how they posses the unique ability to regrow dismembered body parts.
However, a team of Japanese scientists from Tohoku University has written in PeerJ to report that cellular mechanisms are behind this natural ‘superpower’.
“Currently our knowledge of biology is quite limited because most studies have been performed using so-called model animals like mice, flies, worms and fish etc,” said Yuichiro Nakajima, corresponding author of the study. “Given that millions of species exist on the earth, it is important to study various animals and broaden our knowledge.”
For its study, the team looked at Cnidarian jellyfish that have been around for approximately 500m years and are known for their stinging cells. They form part of a unique group of animals that are not bilaterally symmetrical and also possess the capacity to regenerate body parts.
A Cladonema polyp prior to becoming a jellyfish. Image: Sosuke Fujita, Tohoku University
The results
The team used Cladonema pacificum – a jellyfish species from the Cnidaria phylum that has branching tentacles – to investigate the spatial pattern of cell proliferation and their roles during jellyfish development and regeneration.
The distribution of cells play a key role in DNA replication through cell division resulting in new ‘daughter’ cells identical to the ‘parent’ cell. This revealed distinct groups of proliferating cells in the sexual life-stage, appearing uniform in the umbrella-shaped portion of their body while clustered in the tentacles.
When food was withheld or cell proliferation was blocked, the team saw the growth of the jellyfish stop, with defects in tentacle branching. This suggests that free-swimming adult jellyfish in the sexual stage have proliferating cells that play a key role in their body-size, tentacle shape and regeneration.
Additionally, when food wasn’t available, the jellyfish gradually decreased in body size over 24 hours, showing that they are able to adapt to their environments quite quickly.
