Worms are not the first thing that come to mind when one thinks of space travelers. However, that is exactly what the researchers from Tufts University decided to send to the International Space Station (ISS) on January 10, 2015. The group of planarian flatworms (Dugesia japonica) selected for their ability to regenerate any body part, were in varying states. Some were left whole, others had their head or tail sliced off, while a select few were shipped with neither head nor tail!
Though that may sound cruel, the dismembered worms, sealed in tubes filled half with water and half with air, were on an important mission. They were being sent to space to observe the impact of microgravity and geomagnetic fields on tissue regeneration and repair of damaged organs and nerves, critical for understanding how wounds heal in space. A control group of worms on Earth was sealed in spring water in the same manner as their space counterparts and kept in darkness at 20 degrees Celsius for the same amount of time.
When the space worms returned to Earth on February 11, they had undergone numerous changes, none of which were observed in their counterparts on Earth. The most interesting was a decapitated worm that had returned from space with two heads – one at each end of its body. This is the first time in the 18 years the scientists have been studying the flatworms that they have observed a natural occurrence of double headedness. When they amputated the mutated worm’s heads, the middle fragment regenerated another two heads, proving without doubt that the five-week sojourn to space had permanently altered the worm’s physiology. The scientists also noted that specimens which had left Earth intact had multiplied into two or more identical entities through a process called spontaneous fission.
The researchers who have spent nearly two years studying the space worms say they behaved differently from the ones in the control group. When placed in fresh spring water, they became partially paralyzed and immobile for up to two hours. Their Earthly counterparts, on the other hand, encountered no such issues. This has led the scientists who published the results of their study in the journal Regeneration on June 13, to conclude that the worms had altered their biological state to adjust to the environment in space and were, therefore, having a hard time adjusting to normal water conditions on Earth.
The two groups also reacted differently to light. Specimens from each group were placed in an area, half of which was illuminated by red light, which is not visible to worms, and the other half with blue light. According to the researchers, 95.5 percent of the control worms spent their time in the dark, while only 70.5 percent of the space worms did the same.
The study, led by the Allen Discovery Center at Tufts University, does have some limitations. For one, the sample size was small. It was also hard to mimic the temperatures experienced by the worms in space over the course of the entire mission. Future experiments will utilize real-time data from space and adjust the temperatures as necessary for the control group on Earth. Additionally, the stress of liftoff and re-entering the atmosphere was not replicated, on Earth, something the researchers plan to rectify during the next study. Furthermore, the amputation of worms was done on Earth. In the future, the scientists hope the worm dismembering will occur aboard the ISS.
According to NASA, understanding how the flatworm re-grows its tissue could enable scientists to create new technologies that will allow space travelers on long missions to self-heal, and perhaps even re-grow lost limbs! The research can also help people suffering from a wide range of injuries and physical impairments, including spinal cord injuries, and degenerative brain diseases such as Parkinson’s. And in case you are wondering, the researchers are still trying to find out what caused the space worm to generate two heads — so stay tuned!
Resources: now.tufts.edu, gizmodo.com,