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Tuesday, April 18, 2017

The Smallest Warrior on Earth: the Water Bear


Tardigrades, also known as water bears or moss piglets, are one of the most unbelievable animals on Earth. A weird mix of cute and alarming, water bears are 0.5 mm long, short and stubby with eight dainty legs. They are extremely diverse, found on all corners of the planet. Scientists estimate that for every one of us, there are at least a billion of them. But what is most incredible about water bears is their unimaginable resilience.

Water bears can withstand temperatures as scorching as 304° F or as freezing as -458° F. When exposed to the vacuum of space, they were not at all affected by microgravity and cosmic radiation. But perhaps most amazing is the water bear’s ability to survive for more than 30 years without water. Thirty years, or more than 10,950 days, is more than 3650 times longer than the average human can survive without water!


Their incredible resilience is made possible by a very special ability. When sensing an oncoming dry period, the water bear brings its head and limbs into the exoskeleton, making itself into a tiny ball, like a roly poly. It will remain in this stasis, unmoving until it’s reintroduced into water.


Tardigrades are found everywhere, from parking lots to the bottom of the Mariana Trench, very common and accessible. Up until this year, scientists were unable to crack the mystery of the water bear. Some hypothesized that the sugar trehalose was responsible. In other organisms like the brine shrimp, to prevent desiccation, trehalose would be produced to replace water and prevent the degradation of molecular structures. Others even believed that, because of their unique ability to survive in outer space, tardigrades might be extraterrestrial! Only recently was a researcher at University of North Carolina at Chapel Hill able to uncover exactly how tardigrades can handle such extreme stresses.


Tardigrades have unique genes that allow them to create a glass matrix to protect their cells, a process known as vitrification. Proteins, TDPs, form a glass coating. The tardigrade remain in a suspended state until re-hydration, when the proteins melt, and the tardigrade can continue on with its little life. In the near future, this discovery might enable scientists to use TDP to freeze-dry vaccines and medication to areas lacking immediate access. In the distant future, this discovery might even enable placing humans in stasis for space travel or when they have a dangerous illness to await a cure.


Post by Swathi P., Homework Assistant

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