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What are the molecular and cellular characteristics of immortal organisms? Can we mimic them?

Image credit: Muzina Shanghai

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Shubhankar Kulkarni
Shubhankar Kulkarni Oct 16, 2020
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Necessity

Is the problem still unsolved?

Conciseness

Is it concisely described?

What are the molecular and cellular characteristics of immortal organisms or organisms that live exceptionally long?

Let's list all such characteristics and then try to come up with ways in which these characteristics can be harnessed to extend the human lifespan.

This could become a useful database for researchers to take up ideas from.
14
Creative contributions

The curious case of Turritopsis dohrnii

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Povilas S
Povilas S Nov 24, 2020


T. dohrnii, a.k.a. “immortal jellyfish”, is one of a few and the best-known species in the animal kingdom to be able to undergo cell transdifferentiation and return to the juvenile stages of its life cycle, starting it anew. There is some evidence of other species of jellyfish being capable of life cycle reversal [1,2], but in the case of T. dohrnii it's the most obvious, and also this seems to be the only species in which this mechanism is turned on by aging. There appears to be no limit to how many times the reversed process can be repeated, making T. dohrnii biologically immortal. However, in their natural environment, these creatures often succumb to predation, disease, or other deadly environmental factors and don‘t start the „reversed aging“. Therefore it‘s not the world‘s dominant aquatic species, however, it has become widespread around the world through silent invasion due to its small size [3].

Even though this miraculous species seems to hold the key to amazing scientific discoveries, and its peculiar immortality feature has first been noticed in the 1980s, very little research in understanding inner biological processes leading to such a unique skill has been made since. The main reason for this might be that the species is very hard to cultivate in captivity - the only person who managed to do that for longer periods of time is Japanese scientist Shin Kubota, who has reported that over the period of two years his population of T. dohrnii has rebirthed itself 11 times. Another reason that might hold the research back has been proposed to be the lack of hydroid experts and in general - small-bodied organisms being more poorly studied than larger-bodied organisms. Nevertheless, some research has been done:
  • The first-ever study of T. dohrnii life cycle reversal.
  • The complete mitochondrial genome of T. dohrnii sequenced and analyzed in this 2017 study.
  • This relatively recent study is an attempt to understand molecular biology and genetics behind the reversed life cycle of T. dohrnii.
If you want more information about T. dohrnii and its rejuvenation I recommend this video, which summarizes important points and this extensive and interesting to read article.
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Can we learn from exceptionally long-living plants?

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Subash Chapagain
Subash Chapagain Oct 17, 2020
  • Telomerase activity and Telomerase RNA
Bristlecone Pine (Pinus longaeva) is one of the plant species known to live for the longest period of time (almost 5000 years). Molecular biology has revealed that the telomere length and telomerase activity is one of the major distinguishing factors for its exceptionally long life-span .

Previously considered obscured, recent works have revealed the new features of Telomerase gene, mainly that the telomerase RNA component. Usually across species, Telomerase enzyme contains two core components for enzymatic function (that is the maintenance of the telomere cap in the chromosome): one is a protein and the other is an RNA molecule that provides a template for DNA synthesis. This telomerase RNA component from land plants including the pine tree shows an evolutionary connection between ciliates and human telomerase as well, offering new insights into telomerase evolution in eukaryotes.

The telomerase RNA (TR or TER) assembles with the telomerase reverse transcriptase (TERT) protein to form the catalytic core of an enzyme that maintains telomere function and genome integrity by continually adding telomeric DNA repeats onto chromosome ends .Telomerase RNA contains a template to synthesize G-rich telomere repeat arrays catalysed by TERT. In addition, TR includes highly conserved structural domains that serve as a scaffold for binding accessory proteins that facilitate Ribonucleoproteins biogenesis, chromosome terminus and regulation of telomerase enzyme activity .
  • An ability to maintain a productive ectomycorrhizal symbiosis?
When Bristlecone pine (Pinus longaeva) and limber pine (Pinus flexilis), both exceptionally long-living plants, were examined for their relationship with fungal species in their root soil, they were found to have extensive ectomycorrhizal relationship with fungi. A total of 15 ectomycorrhizal fungal species from 3 different genera: 9 species of Rhizopogon, 5 species of Geopora (inclusive of Picoa) and 1 species of Suillus were found. Of these 15 species, all were found at least once on the roots of LP and 10 were found at least once on the roots of BCP. The two most common species were two unidentified species of Rhizopogon and Geopora.

Hence, if we learn from these long-living plants, maybe we should also look into the various ways we can have an extremely beneficial symbiotic relationship with other microbial species that in turn might help us live longer.

[1]Flanary, B. E., & Kletetschka, G. (2005). Analysis of telomere length and telomerase activity in tree species of various life-spans, and with age in the bristlecone pine Pinus longaeva. Biogerontology, 6(2), 101–111. https://doi.org/10.1007/s10522-005-3484-4

[2]Song, J., Logeswaran, D., Castillo-González, C., Li, Y., Bose, S., Aklilu, B. B., Ma, Z., Polkhovskiy, A., Chen, J. J.-L., & Shippen, D. E. (2019). The conserved structure of plant telomerase RNA provides the missing link for an evolutionary pathway from ciliates to humans. Proceedings of the National Academy of Sciences, 116(49), 24542–24550. https://doi.org/10.1073/pnas.1915312116

[3]J. W. Shay, W. E. Wright, Telomeres and telomerase: Three decades of progress. Nat. Rev. Genet. 20, 299–309 (2019)

[4]J. D. Podlevsky, J. J. Chen, Evolutionary perspectives of telomerase RNA structure and function. RNA Biol. 13, 720–732 (2016).

[5]Shemesh, H., Boaz, B. E., Millar, C. I., & Bruns, T. D. (2019). Symbiotic interactions above treeline of long‐lived pines: Mycorrhizal advantage of limber pine ( Pinus flexilis ) over Great Basin bristlecone pine ( Pinus longaeva ) at the seedling stage. Journal of Ecology, 108(3), 908–916. https://doi.org/10.1111/1365-2745.13312

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Not immortal, but very very old shark

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J
Juran Oct 27, 2020
Recently, scientists evaluated the brain of a 245-year-old Greenland shark (Somniosus microcephalus). They are known for their longevity of up to 392 ± 150 years of life expectancy. Shockingly, although the anatomy of the shark's brain was similar to human's, NO changes related to neurological aging were found in the shark's brain .

The scientists speculate that the environmental factors could be the key:
  • life in cold Arctic waters (+4 degrees Celsius)
  • slow movements
  • low aerobic metabolism
  • little mitochondrial oxidative stress
  • high concentrations of trimethylamine (neuroprotective?)
  • low blood pressure compared to other sharks (cardioprotective)

[1]https://link.springer.com/article/10.1007/s00401-020-02237-4?fbclid=IwAR13IuRKKXPCW17Aq3mAaqPv_GXp0owqr8TlejSdAys58-GFqJwJzpDjUOk

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Elephants are more resistant to cancer compared to humans

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Shubhankar Kulkarni
Shubhankar Kulkarni Nov 04, 2020
Cancer mortality does not increase with body size and/or maximum life span in mammals. Elephants have an estimated cancer mortality of 4.81%, compared with humans (11% to 25%). Researchers found out that humans have 1 copy (2 alleles) of TP53 (tumor protein p53 is a tumor suppressor; it regulates cell division by disallowing cells to proliferate too fast or in an uncontrolled way). However, African elephants have at least 20 active copies (40 alleles) of TP53. Active in the sense that they produce proteins regularly. There can be inactive genes such as those on one of the X chromosomes in females.

In elephants, in response to DNA damage, lymphocytes undergo p53-mediated apoptosis at rates higher than those observed in human lymphocytes, due to the high number of copies of TP53. This means that cells with mutations or DNA damage, which can become cancerous, tend to undergo apoptosis and hence, do not become cancer cells.

[1]https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4858328/#:~:text=Compared%20with%20other%20mammalian%20species,apoptotic%20response%20following%20DNA%20damage.

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The immortal flatworm

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Brett M.
Brett M. Nov 26, 2020

Planarians, or flatworms, have been the focus of study for several decades. Although other organisms have been used to investigate the aging process, planarians have provided substantial insight into tissue regeneration and cell stability. Through years of studying planarians, it has been hypothesized that the aging process in humans and other mortal animals is simply the process of accumulated dysfunctional stem cells. And, that flatworms are able to regenerate tissue through neoblast stem cells that are conserved through the embryogenesis stage in development.

If we think about human aging, it is largely due to cell death and an inability to regenerate tissues, which becomes problematic when the dying tissue is an essential organ such as the liver or heart. Astoundingly, planarians take advantage of these neoblasts and are able to regenerate several tissues, even their internal organs! In a series of experiments, researchers were able to test the potency of these neoblast stem cells. They found that a single injection of neoblasts, even after a lethal dose of radiation had killed off all actively cycling cells in the host planarian, was sufficient to regenerate tissue and restore the planarian back to a functional state. Moreover, the injected neoblasts were found to self-renew, generating other stem cells and the restored planarians were even capable of producing new populations, indicating the pluripotency of the neoblasts.

Some examples of these neoblast pluripotent stem cells are of the sigma class that express high levels of SoxP1 and SoxP2 as well as piwi-1 and h2b. From the sigma class, these stem cells transition to gamma, zeta, or nu neoblast subpopulations that have more specific destinations such as the gut, skin, or neurons, respectively. It appears as though only the sigma class of neoblast stem cells are the key to tissue regeneration, as these are the only ones out of the 3 types found to self-renew.

When it comes to translatability, the stem cell biology observed in planarians is conserved within vertebrates and mammals, indicating that we as humans also harness this regeneration power, but have not tapped into it in the same way planarians have. Importantly, the aging process that results from the accumulation of damaged or dying cells is avoided in planarians, likely contributing to their ability to live an immortal life. As long as the planarian has self-renewing neoblasts, the planarian will remain fully functional.

Perhaps we can use CRISPR or genetic targeting techniques to stimulate neoblast self-renewal in humans or, since they are conserved between species, develop methods to introduce neoblasts harvested from planarians to regenerate tissues and reverse the aging process.
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Shubhankar Kulkarni
Shubhankar Kulkarnia year ago
Thank you for the contribution, Brett Melanson ! Certainly, there seems to be great potential here that can be tapped using CRISPR technology. Humans have genes that are similar to the ones that help in regeneration in the Planaria.
1. Smed-rpa-1 - similar to human Replication Protein A1 (RPA1). RPA1 is required for DNA replication, and suppression of Smed-rpa1 led to decreased mitotic activity adult planarians. [1]
2. Smed-rplp0 - similar to human Ribosomal Protein, large, P0
3. Smed-cdc23 - similar to human CDC23
4. Smed-cyclinL1 - similar to human Cyclin L1[2]
5. setd8-1 is required for the persistence of cell division in growing colonies - human SETD8/PR-SET7 (an H4K20me1 lysine methyltransferase) is required for cell cycle progression. [3]
6. Smed-vasa-1 - similar to human Vasa proteins. It helps in planarian stem cell regulation. [2]

References:
1. Reddien PW, Bermange AL, Murfitt KJ, Jennings JR, Sánchez Alvarado A. Identification of genes needed for regeneration, stem cell function, and tissue homeostasis by systematic gene perturbation in planaria. Dev Cell. 2005 May;8(5):635-49. doi: 10.1016/j.devcel.2005.02.014. PMID: 15866156; PMCID: PMC2267917.
2. Wagner DE, Ho JJ, Reddien PW. Genetic regulators of a pluripotent adult stem cell system in planarians identified by RNAi and clonal analysis. Cell Stem Cell. 2012;10(3):299-311. doi:10.1016/j.stem.2012.01.016
3. Oda H, Okamoto I, Murphy N, Chu J, Price SM, Shen MM, Torres-Padilla ME, Heard E, Reinberg D. Monomethylation of histone H4-lysine 20 is involved in chromosome structure and stability and is essential for mouse development. Mol Cell Biol. 2009 Apr;29(8):2278-95. doi: 10.1128/MCB.01768-08. Epub 2009 Feb 17. PMID: 19223465; PMCID: PMC2663305.
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The senescent cells in a naked mole rat are metabolically less active and cannot overcome oxidative stress

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Shubhankar Kulkarni
Shubhankar Kulkarni Oct 16, 2020
The naked mole rat is the same size as a mouse but lives 10 times longer than the latter. It was previously thought that senescence is hard to achieve in the naked mole rat and they show highly effective repair mechanisms. However, in 2018, a research group showed that the naked mole rat displays that same type of senescence as that of any other rodent; however, their senescent cells are "well behaved" - they are metabolically less active - show down-regulation of DNA metabolism, transcription, and translation.

Furthermore, the genes related to the autophagy-lysosome degradation system are misregulated in the senescent cells and the cells showed greater expression of genes related to oxidative stress. The senescent cells cannot overcome the oxidative stress and they die. The researchers speculated that the naked mole rats may have developed a poor defense against reactive oxygen species because oxygen levels are low in their underground burrows. This makes the senescent cells vulnerable to reactive oxygen species. This benefits the naked mole rats since it clears senescent cells from their bodies.

[1]Zhao Y, Tyshkovskiy A, Muñoz-Espín D, Tian X, Serrano M, de Magalhaes JP, et al. Naked mole rats can undergo developmental, oncogene-induced and DNA damage-induced cellular senescence. Proc Natl Acad Sci [Internet]. 2018 Feb 20;115(8):1801–6. Available from: http://www.pnas.org/lookup/doi/10.1073/pnas.1721160115

[2]Kawamura Y, Oka K, Takamori M, Sugiura Y, Oiwa Y, Fujioka S, et al. Senescent cell death as an aging resistance mechanism in naked mole-rat. bioRxiv [Internet]. 2020; Available from: https://www.biorxiv.org/content/10.1101/2020.07.02.155903v1

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Can we learn from Tardigrades?

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Antonio Carusillo
Antonio Carusillo Oct 17, 2020
Tardigrades were described for the first time by Johann August Ephraim Goeze in 1773 and named after as water bears even if they are quite small 1.5 millimetres! To date, roughly more than 1,000 species have been observed in diverse habitats such as marine, freshwater or limno-terrestrial environments. Even though tardigrades require surrounding water to grow and reproduce, they have the ability to tolerate almost complete dehydration. In fact, when facing desiccation, tardigrades lose body water and enter a contracted dehydrated state called anhydrobiosis, which is a reversible ametabolic state .



In this state, tardigrades can endure a wide range of extreme conditions against which humans – and most the other organisms – if exposed would drop dead instantly like:

  • Temperature from −273 °C ( the actual Space temperature ! ) to nearly 100 °C ( human flesh can start burning at 44°C and from 80°C on you may be considered ready for KFC )
  • high pressure (7.5 GPa) to put this in a prospective the Mariana Trench, the deepest part of the ocean reaches a pressure of 0.1 GPa! Without any special suit, a human body won’t withstand more than 4 atm, 0.0004 GPa and a soviet war submarine Alpha class will barely make it at 0.01 GPa ( deep diving at 4000 feet, slighlty more than 1 km below the water level)
  • it can be immersed in an organic solvent ( no explanation needed )
  • it can be exposed to a high dose of irradiation roughly up to 2000 Gy ( Gamma rays) , in case you wonder 10 Gy are enough to kill a human, you do the math
  • it can be even dropped in the open space and this dude won’t even flinch ( I guess you saw it coming)
So much for the tiny water bears, uh?


What seems to be the description of the Giger’s creature – the Alien – may offer us new insights toward “super-genes” or features we may exploit for ourself.

In fact, in the past years, a lot of research groups have focused their attention on the analysis of gene expression ( transcriptomics and proteomics ) of these super creatures.
An interesting example in translating Tardigrades super-powers to humans was published in Nature where the researchers by analysing the transcriptomic data from the Tardigrades could identify a “ tardigrade-unique DNA-associating protein “ and if they express such protein in human cells they found that this could suppress X-ray-induced DNA damage by ∼40% and improves radiotolerance!

Thus we can envision a future in which by better understanding the genetic “treasure” of such creature we may be able to develop novel genetic approaches to increase human chance to survive in extreme environments!

[1]Jönsson KI, Holm I, Tassidis H. Cell Biology of the Tardigrades: Current Knowledge and Perspectives. Results Probl Cell Differ. 2019;68:231-249. doi: 10.1007/978-3-030-23459-1_10. PMID: 31598859.

[2]Gamma Rays: Horikawa DD, Sakashita T, Katagiri C, Watanabe M, Kikawada T, Nakahara Y, Hamada N, Wada S, Funayama T, Higashi S, Kobayashi Y, Okuda T, Kuwabara M. Radiation tolerance in the tardigrade Milnesium tardigradum. Int J Radiat Biol. 2006 Dec;82(12):843-8. doi: 10.1080/09553000600972956. PMID: 17178624.

[3]Hashimoto, T., Horikawa, D., Saito, Y. et al. Extremotolerant tardigrade genome and improved radiotolerance of human cultured cells by tardigrade-unique protein. Nat Commun 7, 12808 (2016). https://doi.org/10.1038/ncomms12808

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Cancer control in long-lived mammals

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RG
Ruby Grewal Dec 11, 2020
Examining individual long-lived species is interesting and can certainly give us insights into the aging process. I came across a paper that used another approach. Their premise was that species-specific gene expression changes are unlikely to be applicable across species, and that research should be focused on identifying gene networks across many mammalian species that contribute to aging in general. They used a novel method to identify correlation between gene evolution and the evolution of long lifespans across 61 mammalian species. They found a correlation between longevity and pathways that controlled cancer. In large long-lived mammals genes related to cell cycle, DNA repair, cell death, the IGF1 pathway, and immunity were found to be under increased evolutionary constraint that is these genes evolved slower. Species that were exceptionally long-lived for their body size were found to have increased constraint in inflammation, DNA repair, and NFKB-related pathways, which means that genes that control these pathways are less likely to tolerate mutations. This study found only a few genes and no significant pathways that were under positive selection in longer-lived species.

It’s interesting that potential longevity treatments found in other organisms such as telomerase has limited applicability in human due to the risk of cancer. In fact, telomerase reactivation is seen in nearly all cancer cells. Stem cell therapy may also have limitations as they are thought to be the source of some, and possibly most cancers. It’s also interesting that two potential anti-aging drugs metformin and rapamycin are also used to prevent and treat cancer. This suggests that examining how long-lived organisms control and prevent cancer might provide insights that could be applicable to human longevity.

[1]Kowalczyk A, Partha R, Clark NL, Chikina M. Pan-mammalian analysis of molecular constraints underlying extended lifespan. Elife. 2020 Feb 11;9:e51089. doi: 10.7554/eLife.51089. PMID: 32043462; PMCID: PMC7012612.

[2]Camps M, Herman A, Loh E, Loeb LA. Genetic constraints on protein evolution. Crit Rev Biochem Mol Biol. 2007;42(5):313-326. doi:10.1080/10409230701597642

[3]Guterres AN, Villanueva J. Targeting telomerase for cancer therapy. Oncogene. 2020 Sep;39(36):5811-5824. doi: 10.1038/s41388-020-01405-w. Epub 2020 Jul 30. PMID: 32733068; PMCID: PMC7678952.

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Shubhankar Kulkarni
Shubhankar Kulkarni10 months ago
Thank you for your contribution Ruby Grewal ! The results from the first paper you cited certainly propose a reason (answer Peto's paradox at least partly) for Peto's paradox. Along with a high copy number of tumor suppressor gene P53 (in elephants), evolved gene networks can help in retraining inflammation and promoting DNA repair and NFKB-related pathways, like you suggested.
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Hydra stem cells are immune to changes in the nuclear envelope architecture

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Shubhankar Kulkarni
Shubhankar Kulkarni Oct 16, 2020
Hydra is known for its unlimited lifespan and non-senescence. Lamin family of proteins plays a role in regulating senescence and longevity in humans. For example, the accumulation of prelamin A in the cell nuclei leads to loss of heterochromatin and makes inaccessible DNA regions accessible for DNA repair. Interestingly, in Hydra, although Lamin is necessary, the stem cells tolerate changes in the concentration of lamin (overexpression, downregulation, and mislocalization). Hydra stem cells are flexible enough to disturbances in the nuclear envelope structure. This robustness may have provided indefinite self-renewal capacity to Hydra stem cells. This tolerance to changes in Lamin concentration is a sign of reduced complexity in the organism (no specialized concentration-dependent functionality). Researchers speculate that this relatively low complexity of the nuclear envelope architecture might allow for extreme lifespans.

[1]Lattanzi G, Ortolani M, Columbaro M, Prencipe S, Mattioli E, Lanzarini C, et al. Lamins are rapamycin targets that impact human longevity: a study in centenarians. J Cell Sci [Internet]. 2014 Jan 1;127(1):147–57. Available from: http://jcs.biologists.org/cgi/doi/10.1242/jcs.133983

[2]Klimovich A, Rehm A, Wittlieb J, Herbst E-M, Benavente R, Bosch TCG. Non-senescent Hydra tolerates severe disturbances in the nuclear lamina. Aging (Albany NY) [Internet]. 2018 May 10;10(5):951–72. Available from: https://www.aging-us.com/lookup/doi/10.18632/aging.101440

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The oldest koi

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Deru Xu
Deru Xu Oct 28, 2020
Generally speaking, the life span of a koi is about 25 to 35 years. In a fish pond in a temple in Higashi-Shirakawa Village in Kamo County, Gifu Prefecture, Japan, a koi named "Hanako" lived for 226 years and died in 2006. It has survived for more than two centuries. In order to analyze the actual age of "Hanako", Professor Masayoshi Hiro from the Animal Science Laboratory of Nagoya Women's University used tweezers to remove two scales located on different parts of "Hanako". She conducted analysis and calculations through a microscope for 2 months.Scientists also analyzed 5 other koi in the same pond. The study found that all koi survived for more than a century. Among them, the koi named "Aoi" lived for 170 years old, and the white "Yuki" also had 141 years old.
Although the exact reason for the longevity of these koi is still unknown, the key may be the environment in which these koi live (clear and clean mountain spring water) and enough care from the owner.
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Hydra is in an unending growth phase

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Shubhankar Kulkarni
Shubhankar Kulkarni Oct 16, 2020

A high turnover of cells is observed in a Hydra. Hydra harbors a large number of stem cells and they are continuously dividing. Therefore, there is always a high proportion of dividing cells compared to non-dividing cells. In contrast, in humans, the percentage of dividing cells in an adult is not more than 20%. Cells in the Hydra are constantly eliminated either by differentiation, programmed cell death, or budding. In the case of elimination by differentiation, cells migrate along the body axis towards the foot and the tentacle region. They differentiate at the edges and are then lost by sloughing. Therefore, the formation of senescent cells in the Hydra is extremely rare.

[1]Dańko MJ, Kozłowski J, Schaible R. Unraveling the non-senescence phenomenon in Hydra. J Theor Biol [Internet]. 2015 Oct;382:137–49. Available from: https://linkinghub.elsevier.com/retrieve/pii/S0022519315003227

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Darko Savic
Darko Savic10 months ago
If someday in the distant future we were to function in a similar manner I imagine our cardio-vasculature and intestines would have to be flawless first. Most of our cells would be shed through it.

Also, we would have to figure out a way to retain memories while shedding brain cells.
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Shubhankar Kulkarni
Shubhankar Kulkarni10 months ago
Darko Savic The latter part of your comment is the trickiest. The "fresh" cells need to have the exact same connections in order to replace the original cell. I think rejuvenating the existing cell will be the most feasible way, currently.
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Darko Savic
Darko Savic10 months ago
Shubhankar Kulkarni or if we figure out a way to save our memories digitally and re-upload them on demand. Then we could just accept the fact that we are dynamic, ever-changing beings in every sense, including personality, memories, etc. The changes would be gradual, pretty much as they are now. You would be a different person every few decades. A moving average:)
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Egg-laying capacity of Lobster (Homarus americanus) increases with age

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Shubhankar Kulkarni
Shubhankar Kulkarni Jan 28, 2021
The average number of eggs laid by an older female (for example, age 31 years) Lobster is about 78,000, which was about 30-fold more than those laid by a younger female (for example, age 7 years). So basically the reproductive value at an older age is about 32-fold that of the younger age. This is the exact opposite of humans where the reproductive capacity declines with age in both men and women.

Moreover, this capacity is not just because of an increase in the size of the females lobster. Another study noted that the length of the lobster increases in an arithmetical series and the egg production increases in a geometrical series, suggesting that mechanisms other than simply the increases in body size are involved in the production of eggs with age.

[1]Cailin Xu, David C. Schneider, Efficacy of conservation measures for the American lobster: reproductive value as a criterion, ICES Journal of Marine Science, Volume 69, Issue 10, December 2012, Pages 1831–1839, https://doi.org/10.1093/icesjms/fss143

[2]Allen, E. (1895). The Reproduction of the Lobster. Journal of the Marine Biological Association of the United Kingdom, 4(1), 60-69. doi:10.1017/S0025315400050773

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Lobster (Homarus americanus) tissues retain telomerase expression

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Shubhankar Kulkarni
Shubhankar Kulkarni Jan 29, 2021
Unlike mammals, lobsters (Homarus americanus) grow throughout their life and the occurrence of senescence is slow. Mammals have high growth rates in the early phases of development and no growth in the adult and senescent phases. High telomerase activities were detected in all lobster organs. It is, therefore, concluded that lobsters maintain long‐term cell proliferation capacity (indefinite growth) and prevent senescence even in adult stages using ubiquitous and uninterrupted telomerase activation.

[1]Klapper W, Kühne K, Singh KK, Heidorn K, Parwaresch R, Krupp G. Longevity of lobsters is linked to ubiquitous telomerase expression. FEBS Lett. 1998;439:143–6.

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Modification of telomerase present in somatic cells

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Nitish
Nitish Jan 29, 2021
It's good we are exploring nature for a robust alternative for longevity. But why not to start with our own body? We know the enzyme telomerase which is active in germline cells as well as in stem cells but usually inactivated in normal diploid somatic cells . If we could somehow manage to modify it at the embryonic stage to function normally in all the cell types of individual, half of the problem would be sorted. Yes, it will be half of the problem because I think mortality, ageing or senescence is indeed a complex process, and we couldn't attribute it to only telomere shortening.

[1]https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3370421/

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Shubhankar Kulkarni
Shubhankar Kulkarni9 months ago
I agree with what you say Nitish but the session asks for currently observed characteristics in other organisms that we may be able to replicate in humans to extend the lifespan. What you have suggested, although interesting, is not currently observed in humans. I suggest you start a separate session on activating telomerase even in the later stages of human life. Such a session will also attract different ways in which the goal can be achieved.
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