Nuclear fusion reactions in the sun are the source of the heat and light we receive on Earth. These interactions release a huge amount of cosmic radiation – including X-rays and gamma rays – and charged particles that can be harmful to any living organism.
Life on Earth is protected by the magnetic field that forces charged particles to bounce from one pole to the other as well as the atmosphere filtering out harmful radiation.
But during space travel, the situation is different. To find out what happens in the cell when traveling in outer space, scientists send baker’s yeast to the moon as part of NASA’s Artemis 1 mission.
Cosmic damage Cosmic radiation can damage the DNA of cells, greatly increasing the human risk of developing neurodegenerative disorders and fatal diseases, such as cancer. Because the International Space Station (ISS) is located in one of Earth’s two Van Allen radiation belts – which provide a safe zone – astronauts are not exposed much. Astronauts on the International Space Station experience microgravity, another stress that can dramatically alter cell physiology.
As NASA plans to send astronauts to the Moon, and later to Mars, these environmental pressures are getting more and more difficult. The most common strategy for protecting astronauts from the negative effects of cosmic rays is to physically protect them using the latest materials.
Lessons from hibernation Several studies show that hibernation is more resistant to high doses of radiation, and some scientists have suggested using “artificial or induced hibernation” during space missions to protect astronauts.
Another way to protect life from cosmic rays is to study organisms that can remarkably withstand environmental stresses. Tardigrades, for example, are tiny animals that have shown amazing resistance to a number of stresses, including harmful radiation. This unusual stiffness stems from a class of proteins known as “tardigrade proteins”. Under the supervision of molecular biologist Cory Nislow, I am using baker’s yeast, Saccharomyces cerevisiae, to study cosmic DNA damage stress. We are participating in NASA’s Artemis 1 mission, where our batch of yeast cells will travel to the Moon and back to the Orion spacecraft for 42 days.
This group contains about 6000 coding strains of yeast, in which one gene is deleted in each strain. When exposed to the environment in space, these strains will begin to lag if deleting a particular gene affects cell growth and reproduction. My main project in Nislow’s lab is to genetically engineer yeast cells to make them express proteins specific to tardigrades. We can then study how these proteins can alter cell physiology and resistance to environmental stresses – and most importantly radiation – with the hope that this information will be useful when scientists try to engineer these proteins into mammals.
When the task is complete and our samples are recovered, using barcodes, each strain can be counted to identify genes and genetic pathways necessary to survive damage from cosmic radiation.
Organism’s yeast has long served as a ‘model organism’ in studies of DNA damage, which means that there is strong background information about the mechanisms in yeast that respond to DNA-damaging agents. Most yeast genes that play a role in the response to DNA damage have been studied.
Despite the differences in genetic complexity between yeast and humans, the function of most genes involved in DNA replication and the DNA damage response has remained conserved between the two so that we can obtain a great deal of information about the DNA damage response of human cells by studying yeast.
Moreover, the simplicity of yeast cells compared to human cells (yeast contains 6000 genes while we have more than 20,000) allows us to draw more solid conclusions.
And in yeast studies, it is possible to automate the entire process of feeding and stopping cells from growing in an electronic device the size of a shoebox, while growing mammalian cells requires more space in spacecraft and more complex machinery. Such studies are necessary to understand how astronauts’ bodies can handle long-range space missions and to develop effective countermeasures. Once we identify the genes that play key roles in surviving cosmic radiation and microgravity, we will be able to search for drugs or therapies that can help enhance the resilience of cells to withstand such stresses.
We can then test it in other models (such as mice) before actually applying it to astronauts. This knowledge may also be useful in growing plants outside the ground.
(This story has not been edited by the Devdiscourse staff and is automatically generated from a shared feed.)