Jump to content

Environmental tolerance in tardigrades: Difference between revisions

Add links
From Wikipedia, the free encyclopedia
Browse history interactively
Next edit →
Content deleted Content added
VisualWikitext
start from existing section of Tardigrade, see there for attrib.
 
img
Line 1: Line 1:
⚫
[[File:Richtersius coronifer in active and tun states.png|thumb|upright=1.5|''[[Richtersius coronifer]]'' in active and [[Cryptobiosis|cryptobiotic]] 'tun' states.<br/>A↔P = anterior-posterior; mg = midgut; go = gonad;<br/>pb = pharyngeal bulb; mo = mouth; st = stylet<br/>Scale bars = 100 μm]]

From the early 19th century, [[tardigrade]]s' environmental tolerance has been a noted feature of the group.
From the early 19th century, [[tardigrade]]s' environmental tolerance has been a noted feature of the group.


Line 11: Line 13:
{{further|Cryptobiosis}}
{{further|Cryptobiosis}}


[[File:Desiccation-Tolerance-in-the-Tardigrade-Richtersius-coronifer-Relies-on-Muscle-Mediated-Structural-pone.0085091.s001.ogv|thumb|Video of anhydrobiosis, a form of [[cryptobiosis]], in the tardigrade ''[[Richtersius coronifer]]'']]
⚫
[[File:Richtersius coronifer in active and tun states.png|thumb|upright=1.5|''[[Richtersius coronifer]]'' in active and 'tun' states.<br/>A↔P = anterior-posterior; mg = midgut; go = gonad;<br/>pb = pharyngeal bulb; mo = mouth; st = stylet<br/>Scale bars = 100 μm]]


Tardigrades are capable of suspending their [[metabolism]], going into a state of [[cryptobiosis]].<ref name="Brusca 2016"/> Terrestrial and freshwater tardigrades are able to tolerate long periods when water is not available, such as when the moss or pond they are living in dries out, by drawing their legs in and forming a desiccated cyst, the cryptobiotic 'tun' state, where no metabolic activity takes place.<ref name="Brusca 2016"/> In this state, they can go without food or water for several years.<ref name="Brusca 2016"/> Further, in that state they become highly resistant to [[environmental stress]]es, including temperatures from as low as {{cvt|-272|C|F|0}} to as much as {{cvt|+149|C|F|0}} (at least for short periods of time<ref name="Horikawa 2012">{{cite book |last1=Horikawa |first1=Daiki D. |chapter=Survival of Tardigrades in Extreme Environments: A Model Animal for Astrobiology |doi=10.1007/978-94-007-1896-8_12 |editor1-first=Alexander V. |editor1-last=Altenbach |editor2-first=Joan M. |editor2-last=Bernhard |editor3-first=Joseph |editor3-last=Seckbach |title=Anoxia |volume=21 |pages=205–217 |series=Cellular Origin, Life in Extreme Habitats and Astrobiology |year=2012 |isbn=978-94-007-1895-1}}</ref>), lack of [[oxygen]],<ref name="Brusca 2016"/> [[vacuum]],<ref name="Brusca 2016"/> [[Ionizing radiation|ionising radiation]],<ref name="Brusca 2016"/><ref name="Horikawa Sakashita 2006">{{cite journal |title=Radiation tolerance in the tardigrade Milnesium tardigradum |year=2006 |doi=10.1080/09553000600972956 |last1=Horikawa |first1=Daiki D. |last2=Sakashita |first2=Tetsuya |last3=Katagiri |first3=Chihiro |last4=Watanabe |first4=Masahiko |last5=Kikawada |first5=Takahiro |last6=Nakahara |first6=Yuichi |last7=Hamada |first7=Nobuyuki |last8=Wada |first8=Seiichi |last9=Funayama |first9=Tomoo |last10=Higashi |first10=Seigo |last11=Kobayashi |first11=Yasuhiko |last12=Okuda |first12=Takashi |last13=Kuwabara |first13=Mikinori |display-authors=5 |journal=International Journal of Radiation Biology |volume=82 |issue=12 |pages=843–848 |pmid=17178624 |s2cid=25354328}}</ref> and high pressure.<ref name="Seki Toyoshima 1998">{{cite journal |last1=Seki |first1=Kunihiro |last2=Toyoshima |first2=Masato |title=Preserving tardigrades under pressure |journal=Nature |volume=395 |issue=6705 |pages=853–854 |year=1998 |doi=10.1038/27576 |bibcode=1998Natur.395..853S |s2cid=4429569}}</ref>
Tardigrades are capable of suspending their [[metabolism]], going into a state of [[cryptobiosis]].<ref name="Brusca 2016"/> Terrestrial and freshwater tardigrades are able to tolerate long periods when water is not available, such as when the moss or pond they are living in dries out, by drawing their legs in and forming a desiccated cyst, the cryptobiotic 'tun' state, where no metabolic activity takes place.<ref name="Brusca 2016"/> In this state, they can go without food or water for several years.<ref name="Brusca 2016"/> Further, in that state they become highly resistant to [[environmental stress]]es, including temperatures from as low as {{cvt|-272|C|F|0}} to as much as {{cvt|+149|C|F|0}} (at least for short periods of time<ref name="Horikawa 2012">{{cite book |last1=Horikawa |first1=Daiki D. |chapter=Survival of Tardigrades in Extreme Environments: A Model Animal for Astrobiology |doi=10.1007/978-94-007-1896-8_12 |editor1-first=Alexander V. |editor1-last=Altenbach |editor2-first=Joan M. |editor2-last=Bernhard |editor3-first=Joseph |editor3-last=Seckbach |title=Anoxia |volume=21 |pages=205–217 |series=Cellular Origin, Life in Extreme Habitats and Astrobiology |year=2012 |isbn=978-94-007-1895-1}}</ref>), lack of [[oxygen]],<ref name="Brusca 2016"/> [[vacuum]],<ref name="Brusca 2016"/> [[Ionizing radiation|ionising radiation]],<ref name="Brusca 2016"/><ref name="Horikawa Sakashita 2006">{{cite journal |title=Radiation tolerance in the tardigrade Milnesium tardigradum |year=2006 |doi=10.1080/09553000600972956 |last1=Horikawa |first1=Daiki D. |last2=Sakashita |first2=Tetsuya |last3=Katagiri |first3=Chihiro |last4=Watanabe |first4=Masahiko |last5=Kikawada |first5=Takahiro |last6=Nakahara |first6=Yuichi |last7=Hamada |first7=Nobuyuki |last8=Wada |first8=Seiichi |last9=Funayama |first9=Tomoo |last10=Higashi |first10=Seigo |last11=Kobayashi |first11=Yasuhiko |last12=Okuda |first12=Takashi |last13=Kuwabara |first13=Mikinori |display-authors=5 |journal=International Journal of Radiation Biology |volume=82 |issue=12 |pages=843–848 |pmid=17178624 |s2cid=25354328}}</ref> and high pressure.<ref name="Seki Toyoshima 1998">{{cite journal |last1=Seki |first1=Kunihiro |last2=Toyoshima |first2=Masato |title=Preserving tardigrades under pressure |journal=Nature |volume=395 |issue=6705 |pages=853–854 |year=1998 |doi=10.1038/27576 |bibcode=1998Natur.395..853S |s2cid=4429569}}</ref>

Revision as of 11:09, 28 December 2024

Richtersius coronifer in active and cryptobiotic 'tun' states.
A↔P = anterior-posterior; mg = midgut; go = gonad;
pb = pharyngeal bulb; mo = mouth; st = stylet
Scale bars = 100 μm

From the early 19th century, tardigrades' environmental tolerance has been a noted feature of the group.

Environmental tolerance

In 1834, C.A.S. Schulze, giving the first formal description of a tardigrade, Macrobiotus hufelandi, explicitly noted the animal's exceptional ability to tolerate environmental stress, subtitling his work "a new animal from the crustacean class, capable of reviving after prolonged asphyxia and dryness".[1][2]

Tardigrades are not considered extremophilic because they are not adapted to exploit extreme conditions, only to endure them. This means that their chances of dying increase the longer they are exposed to the extreme environments,[3] whereas true extremophiles thrive there.[4]

Cryptobiosis and the dehydrated 'tun' state

Further information: Cryptobiosis
Video of anhydrobiosis, a form of cryptobiosis, in the tardigrade Richtersius coronifer

Tardigrades are capable of suspending their metabolism, going into a state of cryptobiosis.[5] Terrestrial and freshwater tardigrades are able to tolerate long periods when water is not available, such as when the moss or pond they are living in dries out, by drawing their legs in and forming a desiccated cyst, the cryptobiotic 'tun' state, where no metabolic activity takes place.[5] In this state, they can go without food or water for several years.[5] Further, in that state they become highly resistant to environmental stresses, including temperatures from as low as −272 °C (−458 °F) to as much as +149 °C (300 °F) (at least for short periods of time[6]), lack of oxygen,[5] vacuum,[5] ionising radiation,[5][7] and high pressure.[8]

Surviving other stresses

Marine tardigrades such as Halobiotus crispae alternate each year (cyclomorphosis) between an active summer morph and a hibernating winter morph (a pseudosimplex) that can resist freezing and low salinity, but which remains active throughout. Reproduction however takes place only in the summer morph.[5]

Tardigrades can survive impacts up to about 900 metres per second (3,000 ft/s), and momentary shock pressures up to about 1.14 gigapascals (165,000 psi).[9]

Exposure to space (vacuum and ultraviolet)

The 2007 FOTON-M3 mission carrying the BIOPAN astrobiology payload (illustrated) exposed tardigrades to vacuum, solar ultraviolet, or both, showing their ability to survive in the space environment.

Tardigrades have survived exposure to space. In 2007, dehydrated tardigrades were taken into low Earth orbit on the FOTON-M3 mission carrying the BIOPAN astrobiology payload. For 10 days, groups of tardigrades, some of them previously dehydrated, some of them not, were exposed to the hard vacuum of space, or vacuum and solar ultraviolet radiation.[10] Back on Earth, more than 68% of the subjects protected from solar ultraviolet radiation were reanimated within 30 minutes following rehydration; although subsequent mortality was high, many produced viable embryos.[10]

In contrast, hydrated samples exposed to the combined effect of vacuum and full solar ultraviolet radiation had significantly reduced survival, with only three subjects of Milnesium tardigradum surviving.[10] The space vacuum did not much affect egg-laying in either R. coronifer or M. tardigradum, whereas UV radiation did reduce egg-laying in M. tardigradum.[11] In 2011, Italian scientists sent tardigrades on board the International Space Station along with extremophiles on STS-134.[12] They concluded that microgravity and cosmic radiation "did not significantly affect survival of tardigrades in flight" and that tardigrades could be useful in space research.[13][14]

In 2019, a capsule containing tardigrades in a cryptobiotic state was on board the Israeli lunar lander Beresheet which crashed on the Moon; they were described as unlikely to have survived the impact.[9] Despite tardigrades' ability to survive in space, tardigrades on Mars would still need food.[15]

Damage protection proteins

Tardigrades' ability to remain desiccated for long periods of time was thought to depend on high levels of the sugar trehalose,[16] common in organisms that survive desiccation.[17] However, tardigrades do not synthesize enough trehalose for this function.[16] Instead, tardigrades produce intrinsically disordered proteins in response to desiccation. Three of these are specific to tardigrades and have been called tardigrade specific proteins. These may protect membranes from damage by associating with the polar heads of lipid molecules.[18] The proteins may also form a glass-like matrix that protects cytoplasm from damage during desiccation.[19] Anhydrobiosis in response to desiccation has a complex molecular basis; in Hypsibius exemplaris, 1,422 genes are upregulated during the process. Of those, 406 are specific to tardigrades, 55 being intrinsically disordered and the others globular with unknown functions.[20]

Tardigrades possess a cold shock protein; Maria Kamilari and colleagues propose (2019) that this may serve "as a RNA-chaperone involved in regulation of translation [of RNA code to proteins] following freezing."[17]

Tardigrade DNA is protected from radiation by the Dsup ("damage suppressor") protein.[21] The Dsup proteins of Ramazzottius varieornatus and H. exemplaris promote survival by binding to nucleosomes and protecting chromosomal DNA from hydroxyl radicals.[22] The Dsup protein of R. varieornatus confers resistance to ultraviolet-C by upregulating DNA repair genes.[23]

References

  1. ^ Bertolani, Roberto; Rebecchi, Lorena; Giovannini, Ilaria; Cesari, Michele (2011-08-17). "DNA barcoding and integrative taxonomy of Macrobiotus hufelandi C.A.S. Schultze 1834, the first tardigrade species to be described, and some related species". Zootaxa. 2997 (1): 19–36. doi:10.11646/zootaxa.2997.1.2.
  2. ^ Schultze, Karl August Sigismund (1834). Macrobiotus hufelandii, animal e crustaceorum classe novum, reviviscendi post diuturnam asphyxiam et ariditatem potens [Macrobiotus hufelandii, a new animal from the crustacean class, capable of reviving after prolonged asphyxia and dryness] (in Latin). Curths.
  3. ^ Cite error: The named reference Bordenstein was invoked but never defined (see the help page).
  4. ^ Rothschild, Lynn J.; Mancinelli, Rocco L. (2001). "Life in extreme environments". Nature. 409 (6823): 1092–1101. Bibcode:2001Natur.409.1092R. doi:10.1038/35059215. PMID 11234023. S2CID 529873.
  5. ^ a b c d e f g Cite error: The named reference Brusca 2016 was invoked but never defined (see the help page).
  6. ^ Horikawa, Daiki D. (2012). "Survival of Tardigrades in Extreme Environments: A Model Animal for Astrobiology". In Altenbach, Alexander V.; Bernhard, Joan M.; Seckbach, Joseph (eds.). Anoxia. Cellular Origin, Life in Extreme Habitats and Astrobiology. Vol. 21. pp. 205–217. doi:10.1007/978-94-007-1896-8_12. ISBN 978-94-007-1895-1.
  7. ^ Horikawa, Daiki D.; Sakashita, Tetsuya; Katagiri, Chihiro; Watanabe, Masahiko; Kikawada, Takahiro; et al. (2006). "Radiation tolerance in the tardigrade Milnesium tardigradum". International Journal of Radiation Biology. 82 (12): 843–848. doi:10.1080/09553000600972956. PMID 17178624. S2CID 25354328.
  8. ^ Seki, Kunihiro; Toyoshima, Masato (1998). "Preserving tardigrades under pressure". Nature. 395 (6705): 853–854. Bibcode:1998Natur.395..853S. doi:10.1038/27576. S2CID 4429569.
  9. ^ a b O'Callaghan, Jonathan (2021). "Hardy water bears survive bullet impacts—up to a point". Science. doi:10.1126/science.abj5282. S2CID 236376996.
  10. ^ a b c Jönsson, K. Ingemar; Rabbow, Elke; Schill, Ralph O.; Harms-Ringdahl, Mats; Rettberg, Petra (2008). "Tardigrades survive exposure to space in low Earth orbit". Current Biology. 18 (17): R729 – R731. Bibcode:2008CBio...18.R729J. doi:10.1016/j.cub.2008.06.048. PMID 18786368. S2CID 8566993.
  11. ^ Jönsson, K. Ingemar; Rabbow, Elke; Schill, Ralph O.; Harms-Ringdahl, Mats; Rettberg, Petra (September 2008). "Tardigrades survive exposure to space in low Earth orbit". Current Biology. 18 (17): R729 – R731. Bibcode:2008CBio...18.R729J. doi:10.1016/j.cub.2008.06.048. PMID 18786368. S2CID 8566993.
  12. ^ NASA Staff (17 May 2011). "BIOKon In Space (BIOKIS)". NASA. Archived from the original on 17 April 2011. Retrieved 2011-05-24.
  13. ^ Rebecchi, L.; Altiero, T.; Rizzo, A. M.; Cesari, M.; Montorfano, G.; Marchioro, T.; Bertolani, R.; Guidetti, R. (2012). "Two tardigrade species on board of the STS-134 space flight" (PDF). 12th International Symposium on Tardigrada. p. 89. hdl:2434/239127. ISBN 978-989-96860-7-6.
  14. ^ Reuell, Peter (2019-07-08). "Harvard study suggests asteroids might play key role in spreading life". Harvard Gazette. Retrieved 2019-11-30.
  15. ^ Ledford, Heidi (2008-09-08). "Spacesuits optional for 'water bears'". Nature. doi:10.1038/news.2008.1087.
  16. ^ a b Hibshman, Jonathan D.; Clegg, James S.; Goldstein, Bob (2020-10-23). "Mechanisms of Desiccation Tolerance: Themes and Variations in Brine Shrimp, Roundworms, and Tardigrades". Frontiers in Physiology. 11: 592016. doi:10.3389/fphys.2020.592016. PMC 7649794. PMID 33192606.
  17. ^ a b Kamilari, Maria; Jørgensen, Aslak; Schiøtt, Morten; Møbjerg, Nadja (2019-07-24). "Comparative transcriptomics suggest unique molecular adaptations within tardigrade lineages". BMC Genomics. 20 (1): 607. doi:10.1186/s12864-019-5912-x. PMC 6652013. PMID 31340759.
  18. ^ Boothby, Thomas C.; Tapia, Hugo; Brozena, Alexandra H.; Piszkiewicz, Samantha; Smith, Austin E.; et al. (2017). "Tardigrades Use Intrinsically Disordered Proteins to Survive Desiccation". Molecular Cell. 65 (6): 975–984.e5. doi:10.1016/j.molcel.2017.02.018. PMC 5987194. PMID 28306513.
  19. ^ Boothby, Thomas C.; Piszkiewicz, Samantha; Holehouse, Alex; Pappu, Rohit V.; Pielak, Gary J. (December 2018). "Tardigrades use intrinsically disordered proteins to survive desiccation". Cryobiology. 85: 137–138. doi:10.1016/j.cryobiol.2018.10.077. hdl:11380/1129511. S2CID 92411591.
  20. ^ Arakawa, Kazuharu (15 February 2022). "Examples of Extreme Survival: Tardigrade Genomics and Molecular Anhydrobiology". Annual Review of Animal Biosciences. 10 (1): 17–37. doi:10.1146/annurev-animal-021419-083711.
  21. ^ Hashimoto, Takuma; Horikawa, Daiki D; Saito, Yuki; Kuwahara, Hirokazu; Kozuka-Hata, Hiroko; et al. (2016). "Extremotolerant tardigrade genome and improved radiotolerance of human cultured cells by tardigrade-unique protein". Nature Communications. 7: 12808. Bibcode:2016NatCo...712808H. doi:10.1038/ncomms12808. PMC 5034306. PMID 27649274.
  22. ^ Chavez, Carolina; Cruz-Becerra, Grisel; Fei, Jia; Kassavetis, George A.; Kadonaga, James T. (2019-10-01). "The tardigrade damage suppressor protein binds to nucleosomes and protects DNA from hydroxyl radicals". eLife. 8. doi:10.7554/eLife.47682. ISSN 2050-084X. PMC 6773438. PMID 31571581.
  23. ^ Ricci, Claudia; Riolo, Giulia; Marzocchi, Carlotta; Brunetti, Jlenia; Pini, Alessandro; Cantara, Silvia (2021-09-27). "The Tardigrade Damage Suppressor Protein Modulates Transcription Factor and DNA Repair Genes in Human Cells Treated with Hydroxyl Radicals and UV-C". Biology. 10 (10): 970. doi:10.3390/biology10100970. PMC 8533384. PMID 34681069.
Retrieved from "https://en.wikipedia.org/w/index.php?title=Environmental_tolerance_in_tardigrades&oldid=1265734586"