The living dead may be lurking beneath the deep blue sea.<\/p>\n
Scientists have discovered an aquatic creature that they\u2019re calling a \u201creal-life zombie\u201d \u2014 with tissue that can survive and function on its own for years after being severed from the original animal.<\/p>\n
The bizarre finding, researchers say, raises questions about what it really means to be \u201calive\u201d and could have major implications for humans.<\/p>\n
Many animals can regenerate lost body parts, but one sea creature has a remarkable ability to keep its severed tissue alive for years. edan \u2013 stock.adobe.com<\/p>\n
In the study<\/a>, a team of Canadian scientists focused on an animal called Psolus fabricii.<\/p>\n Better known as the scarlet sea cucumber, this marine invertebrate inhabits the frigid waters of the North Atlantic and Arctic.<\/p>\n Just as lizards can regrow tails<\/a> and starfish can sprout new arms<\/a>, sea cucumbers have impressive healing abilities, capable of replacing major body parts, including internal organs.<\/p>\n \u201cWe\u2019ve always known that sea cucumbers can regenerate remarkably well, but the assumption was that any detached tissue would simply die,\u201d Sara Jobson, who led the research team, said in an interview with Memorial University\u2019s Gazette<\/a>.<\/p>\n But a chance mishap in the lab would challenge that long-held belief.<\/p>\n One day, a researcher was removing a Psolus fabricii from its tank when some of its tube feet \u2014 tiny appendages the animals use to move along the seafloor \u2014 broke off and stuck to the glass.<\/p>\n Rather than dying, the detached pieces appeared to remain alive.<\/p>\n Fragments taken from the Psolus fabricii, a species of sea cucumber, healed and grew over the course of three years. Science Advances<\/p>\n Intrigued, the team decided to investigate further. Researchers removed additional sections from the animal\u2019s tube feet, body and tentacles, then placed the fragments in flowing natural seawater.<\/p>\n The water was teeming with microbes, where detached tissue would normally be expected to break down. But instead, the fragments began healing. Within days, their wounds had closed, and their cells continued dividing and reorganizing.<\/p>\n The tissue also showed signs of immune activity and metabolic function \u2014 meaning it was still carrying out the basic processes needed to stay alive.<\/p>\n Upon closer examination, the researchers found that the fragments appeared to be absorbing amino acids directly from the seawater, essentially taking in nutrients without a mouth. <\/p>\n \u201cNatural seawater is just about the most microbially diverse, least clean approach we could take experimentally,\u201d Rachel Sipler, a senior research scientist at Bigelow Laboratory for Ocean Sciences in Maine, said in a press release<\/a>.<\/p>\n \u201cYet, that rich environment full of bacteria and all this organic matter was actually feeding them and allowing this tissue to heal and grow,\u201d she added.<\/p>\n The fragments didn\u2019t grow into entirely new sea cucumbers or reproduce. Instead, they continued functioning as independent pieces of living tissue.<\/p>\n And they kept at it for more than three years. Researchers eventually ended the experiment so they could publish their findings \u2014 but even then, the tissue showed no signs of aging or decay.<\/p>\n The findings could hold implications for tissue regeneration in human medicine. karrastock \u2013 stock.adobe.com<\/p>\n \u201cWe haven\u2019t grown a new, complete sea cucumber yet, but we are seeing pretty stunning growth and diversification of cells literally years after this tissue was removed,\u201d Sipler said. \u201cIt\u2019s like a lizard that loses its tail. We know some lizards can grow new tails; we\u2019re talking about whether the tail can grow a new lizard.\u201d<\/p>\n The team wanted to see if the same thing would happen with other animals known for their ability to regenerate, so they tried the experiment on sea stars and sea urchins. But tissue taken from those creatures broke down within weeks or months.<\/p>\n That suggests Psolus fabricii may have some unusual biological capabilities that allow its detached tissue to stay alive long after being separated from the rest of its body.<\/p>\n The findings \u201cchallenge the boundary between organismal life and cellular autonomy,\u201d the study authors wrote, \u201ccompelling a redefinition of what it means for tissue to be alive.\u201d<\/p>\n The scientists say their discovery could one day have implications for human medicine.<\/p>\n Understanding how the sea cucumber\u2019s tissue manages to survive, heal and keep functioning for years could help inform future research into tissue repair<\/a>, wound healing<\/a> and cellular aging.<\/p>\n For now, the next step is to take a closer look at the cells\u2019 DNA to determine whether they show signs of aging as they continue to multiply.<\/p>\n