How can space radiation affect humans? Yeast could be giving us the first signs. How is that possible? These small, microscopic fungi have more in common with humans than we can imagine.
This yeast is actually the main ingredient in two studies by Peruvian biologist and doctor of molecular genetics Sergio Santa María Guerra, who conducts research at the NASA Ames Research Center in California.
“It is the same yeast used to make bread and beer, just a little genetically modified (…) Yeast is ideal for research because it is very malleable, easy to process and easy to measure.” It are single-celled organisms that have close similarities to humans, for example in the way they repair genetic damage or how they respond to radiation. There are processes that are similar,” said Santa María in an interview with La Nación after speaking at the Central American Space Congress in our country last week.
In short: They want to send people to the moon and even beyond, where they will conduct research for weeks and which will serve as a gateway to Mars; But to do this, science must first examine how this might affect Homo sapiens. And organisms as small as yeast are suitable for this.
“We don’t know what can happen to people when they are exposed to this radiation, this microgravity. What happens to the human body? That’s why we have to investigate,” he said.
Yeast for studying radiation
Santa María is the lead investigator on two missions called BioSentinel and Leia. The first was launched as part of the Artemis I mission to the Moon, a few hours after the launch of the Orion capsule, this experiment was launched.
The yeast cells were on board a CubeSat, a type of miniature satellite, a high-tech cubic device that will perform the task of collecting information that can only be achieved from space and in weightlessness. These cells are placed on liquid cards.
“This CubeSat was designed for space and is said to have the ability to preserve living organisms: protect them from the temperatures and vacuum of space, monitor the growth of yeast and has a radiation detector that not only measures it, but also characterizes it based on radiation,” he explained.
This experiment will allow us to study how biology responds to the effects of space radiation at the genetic level, and this knowledge will bring human missions closer to our current goal.
In other words, understand how long it takes yeast cells to repair damage caused by exposure to this radiation in a microgravity environment.
The surveys also measure other variables such as temperatures and other conditions. However, radiation is one of the most important. Because in space, astronauts are not exposed to the magnetosphere, which is, so to speak, the earth’s protective layer or shield that protects us from space radiation. If they went deeper into the solar system, they would no longer have this protection and the radiation could be harmful.
For the Santa María project type, the CubeSat measures 10 x 20 x 30 centimeters (about the size of a shoebox). Due to the properties of this structure, a biological experiment had its limitations: flies or rodents could not be placed; It depended on microorganisms. The yeast was ideal for this.
BioSentinel is the biological mission that has traveled the longest distances in space, already over 20 million kilometers into space. And this will help to remotely analyze how radiation and weightlessness affect yeast.
“So far we have seen that the radiation received is already enough to trigger a reaction in the yeast. And yeast cells are more resistant than those in humans. We can’t extrapolate, but we can measure equivalences. “These data show us that the amount of radiation they received in the laboratory already triggers a reaction in yeast and is probably greater in humans,” the scientist showed.
Other uses of yeast
Santa María describes the Leia mission as a “more advanced BioSentinel.” This mission has already started work, but it will leave Earth in 2026. And it will fly on a lunar rover, so it will be close to the lunar surface and orbit.
In this new mission, yeast will be used for two purposes: one to find the answer to the lunar environment and the other to do bioproduction. The word bioproduction can cause confusion, Santa María explains that it involves modifying cells so that they produce “something interesting”. In this case, a protein is being studied to create a compound that will help improve the vision of astronauts.
“We want to know what happens on the moon, but the radiation and gravity environment is different. On the moon the gravity is one sixth of the gravity on Earth, it is not microgravity, but it is a much lower gravity than ours,” he said.
In addition, the radiation on the Moon is different because, as he explained, the cosmic lunar rays hit the Moon and bounce back. This could have negative effects on biological cells.
The idea is to see how cells react under these conditions of radiation and gravity, but also to see how antioxidants work.
This is particularly important as NASA plans to build a space station in lunar orbit in the future. Knowing how cells respond can help advance the path and better protect future astronauts.