Cryptobiosis
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Cryptobiosis or anabiosis is a metabolic state in
Forms
Anhydrobiosis
Anhydrobiosis is the most studied form of cryptobiosis and occurs in situations of extreme
Invertebrates undergoing anhydrobiosis often contract into a smaller shape and some proceed to form a sugar called trehalose. Desiccation tolerance in plants is associated with the production of another sugar, sucrose. These sugars are thought to protect the organism from desiccation damage.[4] In some creatures, such as bdelloid rotifers, no trehalose has been found, which has led scientists to propose other mechanisms of anhydrobiosis, possibly involving intrinsically disordered proteins.[5]
In 2011,
As of 2004, such an application of anhydrobiosis is being applied to vaccines. In vaccines, the process can produce a dry vaccine that reactivates once it is injected into the body. In theory, dry-vaccine technology could be used on any vaccine, including live vaccines such as the one for measles. It could also potentially be adapted to allow a vaccine's slow release, eliminating the need for boosters. This proposes to eliminate the need for refrigerating vaccines, thus making dry vaccines more widely available throughout the developing world where refrigeration, electricity, and proper storage are less accessible.[8]
Based on similar principles, lyopreservation has been developed as a technique for preservation of biological samples at ambient temperatures.
Anoxybiosis
In situations lacking oxygen (a.k.a., anoxia), many cryptobionts (such as M. tardigradum) take in water and become turgid and immobile, but can survive for prolonged periods of time. Some ectothermic vertebrates and some invertebrates, such as brine shrimps,[13] copepods,[14] nematodes,[15] and sponge gemmules,[16] are capable of surviving in a seemingly inactive state during anoxic conditions for months to decades.
Studies of the metabolic activity of these idling organisms during anoxia have been mostly inconclusive. This is because it is difficult to measure very small degrees of metabolic activity reliably enough to prove a cryptobiotic state rather than ordinary metabolic rate depression (MRD). Many experts are skeptical of the biological feasibility of anoxybiosis, as the organism is managing to prevent damage to its cellular structures from the environmental negative free energy, despite being both surrounded by plenty of water and thermal energy and without using any free energy of its own. However, there is evidence that the stress-induced protein p26 may act as a protein chaperone that requires no energy in cystic Artemia franciscana (sea monkey) embryos, and most likely an extremely specialized and slow guanine polynucleotide pathway continues to provide metabolic free energy to the A. franciscana embryos during anoxic conditions. It seems that A. franciscana approaches but does not reach true anoxybiosis.[17]
Chemobiosis
Chemobiosis is the cryptobiotic response to high levels of environmental toxins. It has been observed in
Cryobiosis
Cryobiosis is a form of cryptobiosis that takes place in reaction to decreased temperature. Cryobiosis begins when the water surrounding the organism's cells has been frozen. Stopping molecule mobility allows the organism to endure the freezing temperatures until more hospitable conditions return. Organisms capable of enduring these conditions typically feature molecules that facilitate freezing of water in preferential locations while also prohibiting the growth of large ice crystals that could otherwise damage cells.[citation needed] One such organism is the lobster.[19]
Osmobiosis
Osmobiosis is the least studied of all types of cryptobiosis. Osmobiosis occurs in response to increased
Examples
The brine shrimp Artemia salina, which can be found in the
survives over the dry season when the water of the pans evaporates, leaving a virtually desiccated lake bed.The tardigrade, or water bear, can undergo all five types of cryptobiosis. While in a cryptobiotic state, its metabolism reduces to less than 0.01% of what is normal, and its water content can drop to 1% of normal.[21] It can withstand extreme temperature, radiation, and pressure while in a cryptobiotic state.[22]
Some nematodes and rotifers can also undergo cryptobiosis.[23]
See also
- Biostasis – Coping with environmental changes without adapting
- Cryobiology – Branch of biology
- Cryonics – Freezing of a human corpse
- Cryptobiotic soil– Communities of living organisms on the soil surface in arid and semi-arid ecosystems
- Hibernation – Physiological state of dormant inactivity in order to pass the winter season
- Lyopreservation– Metabolic state of life
References
- PMID 11743072.
- PMID 21840858.
- JSTOR 2445863.
- PMID 24058825.
- S2CID 13072689.
- S2CID 18145344.
- PMID 24324795.
- ^ "High hopes for fridge-free jabs". BBC News. 2004-10-19.
- S2CID 20748794.
- S2CID 11204697.
- ^ Yang G, Gilstrap K, Zhang A, Xu LX, He X. "Collapse temperature of solutions important for lyopreservation of living cells at ambient temperatures." Biotechnol Bioeng. 2010 Jun 1;106(2):247–259.
- ^ Chakraborty N, Chang A, Elmoazzen H, Menze MA, Hand SC, Toner M. "A spin-drying technique for lyopreservation of mammalian cells". Ann Biomed Eng. 2011 May;39(5):1582–1591.
- ^ Clegg et al. 1999
- ^ Marcus et al., 1994
- ^ Crowe and Cooper, 1971
- ^ Reiswig and Miller, 1998
- PMID 11290443.
- ^ S2CID 20894284.
- ^ "Frozen Lobsters Brought Back to Life". 18 March 2004.
- ^ C. Michael Hogan (2008) Makgadikgadi, The Megalithic Portal, ed. A. Burnham
- ^ Piper, Ross (2007), Extraordinary Animals: An Encyclopedia of Curious and Unusual Animals, Greenwood Press.
- ^ Illinois Wesleyan University Tardigrade Facts
- .
Further reading
- David A. Wharton, Life at the Limits: Organisms in Extreme Environments, Cambridge University Press, 2002, hardcover, ISBN 0-521-78212-0