Cryptobiosis
Under cryptobiosis ( Greek , hidden κρυπτός kryptós = and ὁ βίος ho bíos = life, even anabiosis ) refers to a state of organisms in which the metabolic processes are extremely reduced. The term was coined in 1959 by David Keilin . Cryptobiosis is used particularly in water bears (Tardigrada), nematodes (Nematoda) and rotifer before (Rotatoria, Rotifera). In the case of tardigrades in particular, the discovery of cryptobiosis in the 19th century led to pronounced discussions about the nature of living things.
There are several forms of cryptobiosis:
- Anhydrobiosis , formation of permanent stages through dehydration
- Osmobiosis , triggered by increased osmotic pressure
- Anoxybiosis caused by low oxygen levels in the environment
- Cryobiosis caused by low temperatures
In the state of cryptobiosis, living beings are able to survive unfavorable living conditions over a long period of time (for example in the case of anhydrobiotic tardigrade more than a decade). In this state, tardigrade can withstand extremely low temperatures (below 30 K / −243.15 ° C ), radioactivity and elevated temperatures (above 350 K / 77 ° C). The oxygen consumption is reduced to barely measurable values.
In 2018, roundworms were revived after 40,000 years in permafrost , bacteria from the genus Bacillus can even survive 250 million years.
An example from the animal world that combines several cryptobiotic properties are the larvae of Polypedilum vanderplanki .
literature
- AS Parkes, Audrey U. Smith: Transport of Life in the Frozen or Dried State . Br Med J. 1959 May 16; 1 (5132): 1295-1297, PMC 1993429 (free full text).
- David A. Wharton: Life at the Limits - Organisms in Extreme Environment. Cambridge Univ. Press, Cambridge 2002, ISBN 0-521-78212-0 .
- John D. Castello: Life in ancient ice. Princeton Univ. Press, Princeton 2005, ISBN 0-691-07475-5 .
Individual evidence
- ^ David Keilin: The Leeuwenhoek Lecture: The Problem of Anabiosis or Latent Life: History and Current Concept . Proc. Royal Soc. London. Series B. Vol. 150, No. 939 1959, pp. 149-191.
- ↑ Awakened to life again after 40,000 years. Süddeutsche Zeitung, July 28, 2018