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species of jelly, Turritopsis dohrnii, is able to cheat death, curling into

species of jelly, Turritopsis dohrnii, is able to cheat death, curling into a ball (signaling the end for most species), only to grow from its own shriveled remains into an immature juveniles once more. “ Escaping death and achieving potential immortality” writes the first scientists to describe this phenomenon [2], but is this just a neat trick, or can some species really live forever? This jelly is now known as the “immortal jelly”, and its infamy has grown with the years. But no one has published a report that this jelly can truly withstand the test of time; in fact, only one paper has been published suggesting some jelly relatives could live forever. Like many jelly species, members of the group Hydra have a polyp stage that reproduces asexually by budding off little clones, and people have speculated this could last for thousands of years. So Daniel E. Martínez closely watched members of one species, Hydra vulgaris, for 4 years, and in that time very few animals died [3]. Dr. Martínez suggests that since animals that start reproducing only a few days after birth, such as Hydra, tend to kick the bucket earlier than animals that wait, 4 years is a pretty long time. But does that really mean they’re immortal? More information is needed about Hydra, but it’s not the only species people keep for decades, nor the only species that could help us understand if some jellies may last forever. So, to get to the bottom of this I polled the experts. I sent emails to some of the top jelly aquarists asking: do polyp clone populations change over time? Most public aquaria display jellyfish, and to do this they take advantage of the peculiar jelly life cycle. The life of jellies is broken into two parts: the polyp-type stage, which looks like Hydra and divides asexually, and the jelly stage, which grows from polyps and gets on with the busy act of sexual reproduction. To keep the number of exhibit jellies constant, aquarists use polyps as a literal clone bank, cueing them to produce more jellies as needed. Small green Hydra, no more than a few millimeters tall, on a stick. Source: Wikipedia Small green Hydra, no more than a few millimeters tall, on a stick. Source: Wikipedia And do these clone banks ever change or grow old? The answer was a unanimous “yeah, kinda.” According to aquarists at both the Monterey Bay Aquarium and the New England Aquarium, over about six years clonal populations do get “tired.” They become more fragile, don’t produce healthy jellies, and stop responding to environmental signals. Many aquarists replace their polyp stocks with new baby polyps quite regularly, so that none of this fickleness gets in the way of jelly production. The whole colony may continue to kick, but it gets more and more fragile over time. To me, this sounds a lot like aging. When humans die it’s not because a special gene turns on that shouts: “YOUR TIME IS UP!” Rather, little things start breaking all over, cells stop dividing and those that do accumulate mutations, this is why getting older is often accompanied by all sorts of biological issues. The truth is, accumulating mutations and cell gunk isn’t something special about aging people, even clone lines of E. coli bacteria accumulate harmful cellular products over time [4]. This is just the cost of being alive. So does the “immortal jellyfish” Turritopsis dohrnii really last forever, even with all this gunk slowly working its way into its cells and genomes? I’m not convinced. Just because you can reverse your life cycle or clone yourself doesn’t mean you’ve got a get out of jail free card for all the consequences that come with being a living thing in the first place. You are still subject to that nasty gunk build up. Some species like Hydra vulvaris may have evolved ways to clean this gunk and beat the system, but the jury is still out on how, and for how long. While the “immortal” jellyfish Turritopsis dohrnii may be able to turn back its life cycle, it may not escape the inevitable slowing down that comes with age. In other words, while reversing your fate and escaping death for a short while may be a neat trick, it doesn’t guarantee immortality. Work Cited [1] Stefano Piraino, Ferdinando Boero, Brigitte Aeschbach and Volker Schmid (1996). Reversing the Life Cycle: Medusae Transforming into Polyps and Cell Transdifferentiation in Turritopsis nutricula (Cnidaria, Hydrozoa). Biological Bulletin , Vol. 190, No. 3 (Jun., 1996), pp. 302-312 [2] Stefano Piraino, Ferdinando Boero, Brigitte Aeschbach and Volker Schmid (1996). Reversing the Life Cycle: Medusae Transforming into Polyps and Cell Transdifferentiation in Turritopsis nutricula (Cnidaria, Hydrozoa). Biological Bulletin vol. 190, no. 3 pp 302-312 [3] Martínez DE (1998). Mortality patterns suggest lack of senescence in hydra. Exp Gerontol. vol 33 no 3 pp 217-25. [4] Ariel B. Lindner, Richard Madden, Alice Demarez, Eric J. Stewart and François Taddei (2008). Asymmetric segregation of protein aggregates is associated with cellular aging and rejuvenation. PNAS vol. 105 no. 8 pp 3076-3081 doi: 10.1073/pnas.0708931105 Share the post "Are Jellyfish Immortal?" FacebookTwitterGoogle+PinterestDiggE-mail Related Posts Solving the Mystery of the Placental Jellyfish Solving the Mystery of the Placental Jellyfish Malacology Monthly: Cephalopod Compendium Malacology Monthly: Cephalopod Compendium Roger Norman Bamber (1949-2015) Roger Norman Bamber (1949-2015) For Hoff Yeti Crabs Food, Sex, and Birth Determine Living Space At Vents For Hoff Yeti Crabs Food, Sex, and Birth Determine Living Space At Vents These are a few of my favorite species: The magnificent and very large sponge Monorhaphis chuni These are a few of my favorite species: The magnificent and very large sponge Monorhaphis chuni RR Helm (37 Posts) I am a PhD candidate studying jellyfish development and evolution at Brown University. I've participated in numerous research expeditions, studying jellies all over the world, from Africa to the abyss. I am currently studying the beautiful mauve stinger jellies, found in the Mediterranean, and the ghostly Atlantic stinging nettles found on the US east coast. ADAPTATIONS, BIOLOGY, MATING & REPRODUCTION, ORGANISMS TAGGED BUDDING, DEATH, HYDRA, IMMORTALITY, JELLYFISH, LIFESPAN, LONGEVITY, POLYP Post navigation ← Previous Next → 31 comments on “Are Jellyfish Immortal?” Pingback: Are jellyfish immortal? | JellyBiologist JOSEPH GRAVES JR JULY 2, 2013 AT 15:51 The theoretical prediction for immortality revolves around whether a species reproduces via truly symmetrical binary fission. In this scenario it is impossible for senescent causing mutations to accumulate within a lineage. In the case of bacteria, we now realize that one pole gets the good stuff, while the other gets the bad (the bad pole undergoes replicative senescence.). So if these jellyfish could be immortal one would have demonstrate the absence of asymmetric reproduction…no evidence of that is presented. JD HART JULY 2, 2013 AT 23:29 That’s really fascinating! Great read, thanks for posting :D JELLYBIOLOGIST JULY 3, 2013 AT 13:51 Joseph Graves Jr– Really great point! Yes, as far as I know no one has looked at the distribution of cellular components during cell division in cnidarians. When prepping this post, I spoke with Dr. Marc Tatar at my home institution, who researches life history and senescence, and he brought up another point (which I decided to save for its own post). If an organism becomes less able to tolerate stress over time, this is an indication of aging. From what I know, this also has not been looked at. So both symmetric division and homeostatic range need to be looked at in the group. Thanks for bringing this up! KRIS JULY 4, 2013 AT 01:08 Do jellies have stem cells? JELLYBIOLOGIST JULY 6, 2013 AT 13:30 Kris– good question. Hydra has interstitial cells (i-cells for short) that can give rise to other cell types. Presumably other species have cells similar to i-cells, but with so many species out there it’s hard to say. Pingback: Friday Coffee Break « Nothing in Biology Makes Sense! AEOLIUS JULY 7, 2013 AT 09:45 On a side note, has anyone seen photos of Csiromedusa medeopolis, showing the jellyfish from the side? Google is filled with variations of one photo, but little else. JELLYBIOLOGIST JULY 8, 2013 AT 11:15 If it’s not in the original paper, then Lisa Gershwin (the author) is probably the only person who knows. ITSME AUGUST 1, 2013 AT 20:22 Do you think we can use the DNA of this organism to combine in our DNA to produce long life?.. RR HELM AUGUST 2, 2013 AT 12:42 The likelihood is pretty small. They are very very different form us in many ways, and it’s still not clear if they really are immortal. However, I’m constantly surprised by innovation’s strange inspiration. You never know… in the meantime, I’m sticking to exercise and eating healthy foods ;) NATE NOVEMBER 5, 2013 AT 15:18 But is it possible to combine the DNA of jellys with human DNA to produce longer life at all? Pingback: MAGAZIN E grav daca auzim ca suna telefonul desi nu suna? Cum se fabrica realitatea. Poate teoria evolutionista sa explice criza? Cel mai prost joc video. Cand Icebergul cumpara Titanicul.TED Talks Pingback: MAGAZIN E grav daca auzim ca suna telefonul desi nu suna? Cum se fabrica realitatea. Poate teoria evolutionista sa explice criza? Cel mai prost joc… - Gogoloi KELPY AUGUST 9, 2013 AT 05:58 Lol I love the way scientists go about these things. You see if someone was watching you in a bucket for four years you would get stressed too. So what I am trying to say is that often watching behaviour of species in a false environment is not always going to yield results. It just means you can back up your own theory because obviously you would be looking for evidence to support your own theory, or hopefully in the true tradition of science you would also be looking for the opposite. Still fascinating that as a set of species ourselves we are determined to discover any signs of immortality. Viva curiosity JELLYBIOLOGIST AUGUST 9, 2013 AT 12:07 Well, you gotta work with what you’ve got. These animals are nearly impossible to work with in the wild, because they clone themselves and make it difficult to keep track of who is who. None of these results are conclusive, but they do lend clues. And these clues are a nice way to start. While you think 4 years of being watched may be stressful, the opposite could also be true. Being fed regularly and living in clean water may mask signs of aging. In the same way that leaving a human in a perfectly comfortable condition will prevent any broken bones or signs of stress and fatigue. Young animals are often better able to tolerate stress by comparison to older ones. So maybe the animals find this environment really relaxing, and therefore live longer. Who knows? We have to keep plugging along just the same. Looking into what we have. The alternative is to not looking at all, and it’s not nearly as fun ;) JACOB EZEKIEL AUGUST 15, 2013 AT 01:59 CAN YOU LIVE FOREVER.. For thousands of years, thinking people have wrestled with that question. Is there a logical, satisfying explanation—one that harmonizes with both our physical makeup and our natural desire to live forever? Millions of people would answer with a resounding yes! Why? In the Bible, they have found the most satisfying answers about human nature. From the outset, the Bible plainly states that humans, while having some things in common with other creatures, are fundamentally different. For example, at Genesis 1:27, we read that God created humans in his image. How so? He gave us the capacity to display love, justice, and wisdom. And as the One who lives forever, God implanted in us the desire to live forever. He “planted eternity in men’s hearts and minds,” says Ecclesiastes 3:11.—The Amplified Bible. Physical evidence that humans were originally designed to live much longer than we do can be seen in the power of the brain, especially in its potential to learn. The Encyclopedia of the Brain and Brain Disorders states that the long-term memory capacity of the human brain “is virtually unlimited.” Why have this capacity if it were not meant to be used? Yes, in fundamental ways, humans reflect God’s original purpose for mankind. http://www.jw.org/en/publications/magazines/g201308/how-long-canHanna Eisenmenger

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