Tardigrades are one of the most resilient and mysterious life forms on Earth. Also known as tardigrades and moss piglets, these creatures are microscopic eight-legged creatures with no backbone.
Their ability to survive in extreme environments is amazing, including areas so radioactive that they could easily be fatal to humans. They can also survive starvation, lack of air and water, and sub-zero temperatures.
ancient survivors
These remarkable creatures belong to their own phylum (tardigrades) and inhabit some of the more extreme ecosystems on Earth, from the frigid arctic and deep seafloor to scorching deserts and even the vacuum of space. To date, researchers have identified more than 1,300 species of tardigrades; each species is uniquely adapted to conditions that would be lethal to most other life forms.
Evolutionarily speaking, tardigrades are an ancient species. The earliest known fossils date back to the Cretaceous period, about 90 million years ago. Molecular dating shows they originated at least 600 million years ago.
When faced with harsh environments, tardigrades can enter a state called cryptobiosis, effectively suspending nearly all biological processes and placing themselves in suspended animation. This special state allows them to endure extreme dryness, intense radiation and cold. Tardigrades are able to survive radiation because of special mechanisms that protect their genetic material from damage. In fact, they not only survived the dangerous radiation: they were able to recover and resume their normal lives.
Lessons from the tardigrade
Their characteristics make tardigrades a hot topic for scientific research. Researchers hope to unlock the secrets of its special survival mechanism and pave the way for progress in human medicine, space exploration and other fields.
Research has shown that there are many mechanisms that help tardigrades, and a deeper understanding of them is expected to be of great biomedical and industrial value. For example, researchers have recently been discussing the role of a specific class of proteins: those with flexible bodies and no intrinsic structure. Therefore they are named intrinsically disordered proteins.
One subclass is the secretion of abundant heat-soluble proteins. Researchers have recently tried to synthesize these proteins by cloning the underlying genes and transferring them to other microorganisms. Their work showed that this approach can enhance microbial tolerance to desiccation (complete desiccation). This work was published in Nature Communications Biology in May.
Another paper published in the same journal last year looked at molecules called small heat shock proteins and showed in a similar way that they enhance the ability of microorganisms to survive hot conditions and prevent proteins from clumping when drying.
Survival begins with cells
Recently, researchers from China reported a new tardigrade species, Henan small loach. Their findings were published on October 25 in scienceincluding a genome assembly at the chromosome level, revealed many details about the genes that give tardigrades the ability to withstand radiation. They exposed tardigrades to doses of gamma rays 1,000 times higher than the lethal limit for humans and used genomic tools to track which genes were expressed.
Researchers found that thousands of genes were up-regulated when tardigrades were exposed to extreme radiation. Further analysis suggested that radioresistance may be mediated through horizontal transfer of genes acquired from other species in its environment. The researchers also found some genes that are unique to tardigrades, as well as genes that are similar but not identical to other organisms.
In fact, horizontal gene transfer contributes more than 0.5% of tardigrade genes, an important part showing its importance to the survival and evolution of tardigrades. this Add 1 This gene is particularly noteworthy: Tardigrades need it to synthesize betalains, an antioxidant pigment that protects tardigrade cells from radiation damage. The organisms probably got it from a type of bacteria.
A second group of genes related to radiation resistance are unique to the tardigrades themselves. one of them is Step 1which plays a role in repairing damaged DNA mediated by phase separation. the other is NDUFB8related to mitochondrial function. Researchers have found that they are critical to the species’ ability to survive in extreme conditions, and may help maintain cell stability and sustain energy production even under high radiation stress. In fact, tardigrades’ survival advantage begins at the cellular level.
Upcoming applications
The biology of tardigrades seems exotic at this time, and the research exploring it may seem esoteric. But much of biology makes sense from an evolutionary perspective (adapted from Theodosius Dobzhansky), and unraveling the mysteries of tardigrades may soon translate to the real world Challenge breakthroughs and have far-reaching impacts. Recall that scientists developed CRISPR-Cas9 based on bacteria’s unique mechanism for repairing DNA.
Consideration of protein stability in tardigrades. We more commonly use biological therapies such as protein vaccines, antibodies, and enzymes to treat various diseases. If we could find a way to stabilize the proteins involved in these technologies, we could also improve their biological efficacy.
As the field of cell therapy continues to evolve, researchers are looking for technologies to protect these therapeutic products from the harsh conditions they may encounter during storage, transportation, and administration. Tardigrades have unique adaptations that allow them to resist or even avoid cell damage, and researchers could learn from them to find ways to stabilize cells in research and biomedicine.
Taken together, tardigrades provide a unique blueprint for developing powerful biological systems and materials. Their special survival mechanisms could inspire new strategies in medicine, biotechnology and beyond, making key therapies and technologies more resilient, effective and, most importantly, widely available.
Sridhar Sivasubbu and Vinod Scaria work at Karkinos Healthcare Pvt. Ltd., and is an Adjunct Professor at IIT Kanpur and DY Patil Medical College, Pune.
Published – November 6, 2024 at 05:30 AM (IST)
