Tardigrades

News: Among the scientific experiments to be conducted by astronauts onboard the International Space Station (ISS) include the one that will examine the revival, survival, and reproduction of tardigrades in space. Tardigrades.

About Tardigrades

• They are also known as “water bears” as they are robust aquatic animals that have been around for roughly 600 million years.
• Naming: They derive their name from the fact that they look like an eight-legged bear with a mouth that can project out like a tongue.
• Discovery: They were discovered in 1773 by German zoologist Johann August Ephraim Goeze.
• Shape and size: They are about 5 mm long when fully grown, have four pairs of legs, with 4-6 claws on each foot. They can only be seen under a microscope.
• Feeding habit: Tardigrade feed on plant cells, algae and small invertebrates.
• Distribution and habitat: They can be found almost everywhere — from the highest mountains to the deepest oceans.
  • Their most common habitat is the thin film of water found on mosses and lichens, which bestows upon these animals the moniker of “moss piglets”.

Scientific significance of Tardigrades

• Resilient: They are among the most resilient animals which can survive extreme conditions such as exposure to outer space.
• Cryptobiosis: They owe their incredible resilience to cryptobiosis.
  • It is a state in which organisms bring their metabolism to a near-complete standstill in the face of adverse environmental conditions.
• Anhydrobiosis: Tardigrades can reduce their metabolism to less than 0.01% of normal, and drop their water levels by more than 95%, a state called anhydrobiosis.
• Tun state: Both anhydrobiosis and cryptobiosis result in the emergence of a durable shrunken state, called tun, in which tardigrades are able to withstand extreme conditions.
• Protein generation: They produce unique proteins such as cytoplasmic-abundant heat soluble (CAHS) proteins which are key to their resilience.
  • These proteins form a gel-like matrix within their cells, vitrifying and protecting essential cellular components from destruction.
• Potential uses: A better understanding of tardigrades’ survival mechanisms can potentially have several applications: from helping scientists develop more resilient crops to creating advanced sunscreens to preserving human tissues and organs for transplantation.