Scientists have made a groundbreaking discovery regarding the molecular trick that allows tardigrades, also known as water bears or moss piglets, to survive in extreme environments. These tiny eight-legged creatures have long fascinated scientists due to their ability to enter a near-invincible state called anhydrobiosis, where they transform into dehydrated balls known as tuns. This state enables them to withstand extreme temperatures, cosmic radiation, and even being fired from a gun. However, the exact mechanism behind this transformation has remained a mystery until now.
In a recent study published in the journal PLOS One, researchers have finally uncovered the molecular underpinnings of tardigrades’ remarkable survival skills. Tardigrades were first discovered in 1773 by German zoologist Johann August Ephraim Goeze and have since been found to have around 1,300 identified species. These microscopic creatures have been around for approximately 600 million years, surviving all five major extinction events on Earth.
The key to tardigrades’ survival lies in their ability to enter an ultra-dehydrated hibernation state. During this state, their legs retract, and their plump bodies curl into small balls that expel 95% of their moisture. To understand how tardigrades achieve this transformation, the researchers exposed a model species of tardigrades (Hypsibius exemplaris) to various life-threatening conditions such as high levels of hydrogen peroxide, sugar, salt, and extremely low temperatures.
By measuring the chemical environment inside the tardigrades’ cells, the scientists discovered that the creatures produced free radicals during oxidative stress. Free radicals are oxygen atoms with an unpaired electron that can be harmful to most animals as they react with proteins and DNA, leading to mutations. However, in tardigrades, the researchers found that free radicals react with the amino acid cysteine to trigger their transformation into the tun state.
To confirm this, the scientists inhibited the cysteine oxidation process, which prevented the tardigrades from entering the tun state. This finding suggests that tardigrade survival is dependent on the reversible oxidation of cysteines, which regulates their entrance and emergence from survival states.
The researchers’ next step is to investigate how widely this mechanism is shared across different tardigrade species. This discovery opens up new avenues for understanding the remarkable resilience of tardigrades and could potentially inspire future research in developing strategies to protect organisms from extreme conditions.
Tardigrades’ ability to survive in extreme environments has captivated scientists and the public alike. These microscopic creatures have proven time and again that they are true survivors, withstanding conditions that would be lethal to most other organisms. With the molecular trick behind their invincibility now uncovered, scientists are one step closer to unraveling the secrets of these extraordinary creatures.