For a biologist, few words can inspire such awe and wonder as the word tardigrade. Commonly known as water bears or moss piglets, these tiny creatures continue to inspire and make those studying them stand in awe of their almost mystical powers.
Each year, in my biology for science majors class, I order enough tardigrades for all of my students to view them in real life. I then ask them to jump on their cellphones, which I know they have, and explore the wonders of tardigrade biology.
The humble moss piglet was first described in the late 1700s and named “tardigrade” by Lazaro Spallanzani, who was a Naturalist/Catholic priest, commonly paired professions then. These tiny creatures, consisting of more than 1,000 species and averaging about ½ mm in length, might be the living embodiment of our comic book heroes. You can just barely see them with the naked eye but they are pretty common if you were to grab a microscope and peek at their world.
The tiny water bear has survived the vacuum of space, radiation levels that would kill most of life on Earth, extremes of temperature and even the loss of water for decades. The list of superhuman powers that the humble water bear encompasses is nothing short of Marvel and DC comics level lore. Just google the word tardigrade, and you will find an almost limitless supply of videos and articles about them.
Science predicted that tardigrades must have the ability to either block DNA damage or repair it so fast that they suffer no ill impact from it. How they do this is just now coming to light. Moss piglets produce a unique protein called Dsup (damage suppressor). The Dsup protein seems to protect the DNA of tardigrades from damage coming in from the environment, such as radiation.
In 2016, a team of scientists published “Extremotolerant tardigrade genome and improved radiotolerance of human cultured cells by tardigrade-unique protein” in the journal Nature Communications. In short, this team of scientists showed that you could give human cells the high radiation tolerance of tardigrades in lab conditions. Imagine giving the superior radiation tolerance that tardigrades have to all of your cells. No need for the lead vest if you became and X-ray technician or worked in nuclear disaster clean-up.
Just recently another team of scientists shined more “candle” light on the details of how Dsup accomplishes the Marvel- or DC-like superpowers. Dr. James T. Kadonaga, a molecular biologist at the University of California and several other colleagues published “The tardigrade damage suppressor protein binds to nucleosomes and protects DNA from hydroxyl radicals” in the journal “Elife” this month.
The article is based on studies of Ramazzottius varieornatus. They show that the Dsup protein is a nucleosome-binder that prevents hydroxyl radicals from damaging the DNA of the tardigrades. Dsup appears to prevent the typical DNA damage that hydroxyl radicals can cause, acting as a protective shell, and allowing those with it to live in radiation levels that would kill most of life. Understanding the details of tardigrade superpowers could open the door to genetically modifying other species to have their power.