It is possible that some form of memory of the period spent in microgravity can be inherited by epigenetics from future children of the astronauts? The answer is provided by a small laboratory worm, C. elegans, and ready to go to the Space Station.
This time there are wormholes, like Interstellar: worms are just short, the classic worms. But as the tunnels spatiotemporal spoon fed in science fiction films as shortcuts to remote areas of the universe, even these humble nematodes could be used to explore new worlds. Not reducing transport times, unfortunately, but helping astronauts to travel more secure. And to better understand the possible long-term consequences of their stay in space. Consequences that could extend to future children.
Credit: University of Delaware
It is in fact to study biophysics of microgravity, and in particular the transmission of changes from generation to generation by epigenetics, that a team of researchers at the University of Delaware has recruited a team of Caenorhabditis elegans (C. elegans) – the worm most loved by biologists, second only, among model organisms, the lovely Drosophila melanogaster – with the intention of sending them as soon as possible in space. Within two years, this is their wish.
To kill time, they put them in the “clinorotator”. That is not a version of the legendary worms spin the Cosmonaut Training Center in Star City, indeed: just the opposite. That is done to train astronauts to face situations of strong acceleration. The clinorotation, instead, serves to simulate microgravity: the worms are placed in a rotating container and filled with liquid, so as to let them experience a sort of free fall, a floating reduced gravity. It is not insignificant: about one-tenth that of Earth, much like Pluto.
If the choice of a worm as a “model organism” instead of an astronaut can amaze, scientists team ensure that C. elegans has all it takes to carry out the delicate task. About 70% of the genes present in the DNA of any C. elegans – which, it is worth to point out, has exactly 959 cells, 302 of which nerve – they also found in the DNA, say, Samantha Cristoforetti. And it is the genes that scientists are interested. Although it is true that living species that stayed aboard the ISS does not seem to have experienced complications fatal due to microgravity (plants, animals and microbes are all shown able to survive), from the biological point of view the changes recorded are remarkable.
Credit: University of Delaware
“This is probably due to the fact that these organizations are adapting to a new environment, and one of the possible mechanisms of adaptation is in the epigenome alterations: a combination of DNA (genome) and histone proteins associated,” says Chandran Sabanayagam, Delaware Biotechnology Institute, “a kind of biological scaffold that keeps the genome wrapped well and compact. The histone proteins have ends that can be chemically labeled so as to function as switches, able to order the cell whether or not to activate the genes surrounding. And unlike the genome sequence, which usually takes many generations to be changed, the marking of histones can also be affected in the course of a single generation. ”
Indeed, the results presented today previewed, in Baltimore, during the annual meeting of the Biophysical Society, show clear differences between the epigenome of worms grown in normal Petri dishes and that of individuals subjected to microgravity. Significant differences, the scientists point out, many of the genes whose regulation mechanism is influenced by epigenetic alterations observed are involved in the development of the muscles and reproduction. And if it still is not clear how the epigenetic memory will last through successive generations, thanks to the “clinorotated worms” Sabanayagam and colleagues have already managed to select a hundred genes to watch once the load will be on board the Station space.