Lorenzo Ricci
In 1961, Osamu Shimomura and Frank Johnson isolated a protein from jellyfish green light under ultraviolet light. Corals can also glow in various forms, thanks to a similar protein. Now, scientists at Harvard University have genetically modified the three-banded tiger worm to allow the creature to emit a similar green light, according to a new research paper published in the journal Developmental Cell. Their hope is to uncover the secret of renewal.
Most animals exhibit some form of regeneration: hair regrowth, for example, or rebuilding a broken bone by growing new skin. But some creatures are remarkably capable of extraordinary regenerative powers, and studying the mechanisms by which they can achieve this could have important implications for human aging. If a salamander loses a leg, the limb will grow back, for example, while some geckos may separate their tail as a distraction to avoid predators and then grow back. Zebrafish can regrow lost or damaged fins, as well as repair damaged heart, retina, pancreas, brain or spinal cord. Cut a flatworm, jellyfish or sea anemone in half and it will rejuvenate its entire body.
Then there’s the three-banded tiger worm (Hofsteinia Miami), a small creature that looks like a grain of rice, and is so named because of the distinctive triangular markings of cream-colored stripes on its body. If a tiger worm is cut into three pieces, each piece will turn into a fully formed worm in about eight weeks. Found mainly in the Caribbean, Bahamas, and Bermuda, as well as Japan, these worms are voracious predators, not only taking a few bites from fellow tiger worms if they are hungry enough and can’t find other prey. They provide a promising new paradigm for studying regeneration mechanisms.
Co-author Mansi Srivastava, an evolutionary biologist at Harvard University, has been studying tri-band tiger worms since 2010, when he was a postdoc in Peter Redin’s lab at MIT’s Whitehead Institute. They collected about 120 worms in Bermuda and brought them back to Cambridge. Worms didn’t immediately adapt to laboratory life: Srivastava and Ridian had to figure out the right level of salinity for their water and also find an acceptable food source. The worms don’t care about the liver, Redin feeds on planarian flatworms, and some resort to cannibalism to stay alive. In the end, researchers found that tiger worms love it saltwater prawns (As known as sea monkey), and the creatures eventually began to develop and reproduce.
Kathleen Mazza Curl / Mansi Srivastava / Institut Whitehead
There were reports in the 1960s claiming that worms could regrow severed heads, but there was little scientific follow-up. Reddien and Srivastava’s early experiments showed that tiger worms can not only regrow their heads but can also regenerate almost any part of the body, like flatworms – although the two are only distantly related. Srivastava is now running his own laboratory at Harvard University to study regeneration in tiger worms.
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