Pet Planarians: They Don’t Die

Last month saw scientists and philosophers facing off over some big questions. The Royal Institute hosted a debate (Storified here) on whether neuroscience will explain consciousness. Then philosopher Roger Scruton wrote about the limitations of “neurononsense” in the Spectator, which prompted the Guardian’s Neurophilosophy blogger Mo Costandi to scold him publicly for attacking a straw-neuroscientist. After all that, I wanted to pick a more down-to-earth topic. But then I watched a video about immortal worms.

Contrary to popular legend, it turns out the Fountain of Youth is a sewage outlet behind the Queen’s Medical Centre in Nottingham. “Strangely, the water quality’s actually very good,” says Aziz Aboobaker of the University of Nottingham in the video below as he scrabbles around under stones, looking for planarian worms. These tiny animals are more than just a funny face. As a recent paper co-authored by Aboobaker puts it, they “may be potentially immortal or at least very long-lived”.

“I think the coolest thing is that we can take a worm in the lab, chop its head off, and within seven days the worm has regrown a whole new brain,” he says. “The brain, even in a simple worm like that, is incredibly complex. Thousands of cells have all got to be in the right place, all know what they’re doing, so this animal can find its way about.”

This feat is made possible by the large number of stem cells the worms have. “Between 15 and 25 percent of all the cells in this worm are stem cells,” he says. Humans have a certain number of stem cells – in our bone marrow, for example – primarily allowing us to make new blood, new bone, and new muscle cells. But the worms can replace every system in their body.

In a vivid analogy, Aboobaker says this would be like cutting off one of his hands and having it grow into a whole new him – with a new skeleton, organs, and nervous system. But mini-Aboobaker would be only 6 inches tall, since the regeneration process would have just the tissue of that hand to work from.

A stem cell is any cell that is capable of making more than one other type of cell. So all the cells in our body originally came from a cell that was a stem cell – hence the interest in conducting research with stem cells taken from embryos. “The ultimate stem cell is the one-cell embryo before it divides,” he says.

Planarium worms are so fascinating because their stem cells retain the ability to make any other cell into adulthood. “If we can figure out how that animal does it, we’ll hopefully be able to apply those same mechanisms to medical applications,” he says. Aboobaker can also recommend the little critters as pets. “They’re kind of cute, no trouble, perfect pets, and they don’t die.”

Yet another charming thing about the video is that it was apparently a YouTube comment that prompted Aboobaker to conduct the latest research culminating in the recent paper. All quests for the secret of eternal life need a quest-giver.

Video: YouTube | nottinghamscience

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