Scientists Studying a Microscopic Creature Found Something Astonishing About Its Survival

Small and almost invisible, the tardigrades, or “water bears”, are among the toughest survivors on Earth. These eight-legged creatures, which are less than one millimeter in length, have won scientists fame for their unyielding determination to survive in extreme conditions: freezing cold, crushing pressure, and near-total dehydration. Their most astonishing survival feat is possibly the ability to withstand the vacuum of space. In 2008, scientists conducted a study with tardigrades on board the FOTON-M3 spacecraft to determine their limits.

The study, which is discussed in Current Biology (ScienceDirect), directly exposed the tardigrades to outer space’s vacuum as part of the experiment. Much to many people’s surprise, a significant number of these creatures withstood the extreme pressure drop. While the study determined that the vacuum of space is not lethal for tardigrades, solar rays reduce their chances of survival significantly.

One reason these microscopic animals are able to survive such conditions lies in a biological process known as cryptobiosis. When their environment becomes hostile because of dehydration, freezing, or radiation, tardigrades can enter a dormant state in which their metabolism almost comes to a halt. The animal essentially dries out and shrinks into a compact form known as a “tun.” In this state, water content inside the body drops drastically, which prevents many forms of cellular damage, as per studies summarized by National Geographic and other extremophile research.

But cryptobiosis is a part of the story as researchers have discovered that tardigrades are also able to produce unique molecules that protect their cells during high stress. One striking example is a protein called Damage Suppressor (Dsup). Studies discussed in Chemical & Engineering News (ACS) reveal that this protein ties to DNA and protects it from damage caused by X-ray or ultraviolet radiation. Dsup helps maintain the integrity of the organism’s cells, thus protecting genetic material from fragmentation. Additional defenses appear to strengthen this protection. Tardigrades contain antioxidant compounds, including molecules such as betalains, which act as additional defenses that neutralize harmful reactive oxygen species that were generated during radiation exposure. These antioxidants play a key role in limiting cellular damage during stressful conditions, as suggested by research in Space.com.

Another level of protection is provided by heat shock proteins, which are unique molecules that protect other proteins from the effects of changes in temperature and stress. As per studies that have been highlighted by Phys.org, these proteins protect the essential structures in the body from misfolding and destruction, which means that the body can recover when the situation improves. This is an incredibly powerful mechanism when combined with metabolic suspension, and it is what has allowed these creatures to survive in extreme conditions. For scientists interested in exploring the boundaries of life, these creatures have become incredibly important, and are helping scientists not just understand how life can survive on Earth but also how it can survive extreme conditions found in the universe.