| Author: Agnieszka Sikora, PhD |
As part of the Axiom-4 mission to the International Space Station (ISS), in which Polish astronaut Sławosz Uznański-Wiśniewski, PhD is participating, 13 scientific experiments developed by Polish companies and universities will be carried out. Among the research to be conducted by the Polish astronaut is the Yeast TardigradeGene project, involving scientists from the University of Silesia in Katowice.
The Yeast TardigradeGene project was born in 2020, when Izabela Poprawa, PhD, DSc, Assoc. Prof. from the Faculty of Natural Sciences of the University of Silesia, was invited by Prof. Ewa Szuszkiewicz from the University of Szczecin to participate in the MAESTRO grant. The project involved sending various types of organisms, including tardigrades, into space. Unfortunately, funding could not be secured at that time. Several months ago, the topic resurfaced with the announcement of call for proposals for scientific experiments on the International Space Station (ISS).
The project is being carried out by a consortium of three universities: the University of Szczecin – Prof. Ewa Szuszkiewicz (leader) and Franco Ferrari, PhD, DSc, Assoc. Prof. of the University of Szczecin, Adam Mickiewicz University in Poznań – Prof. Hanna Kmita, Łukasz Kaczmarek, PhD, DSc, Assoc. Prof. of the Adam Mickiewicz University, Nina Antos-Krzemińska, PhD, DSc, Assoc. Prof. of the Adam Mickiewicz University, Andonis Karachitos, PhD, DSc, Anna Kicińska, PhD and the University of Silesia in Katowice – Izabela Poprawa, PhD, DSc, Assoc. Prof.
“I invited microbiologist Katarzyna Kasperkiewicz, PhD, DSc, to join my team. I also included young scientists: my graduate students Anna Krakowska and Alper Arslan, and doctoral student Filip Wieczorkiewicz.”
Yeast – photo taken with a transmission electron microscope | Photo by Prof. Izabela Poprawa
The team of researchers from the University of Silesia in Katowice | Photo by A. Chachulska-Żymełka
The team of researchers from Adam Mickiewicz University in Poznań and the University of Szczecin | Photo by G. Figura
Yeast with the tardigrade gene
“While studying tardigrades, which have a very high survival rate in extremely adverse conditions, we began to wonder whether the various proteins that help them survive could also help other organisms,” recalls the biologist from the University of Silesia. “This gave us the idea of creating a genetically modified organism that would contain a tardigrade gene encoding one of the proteins responsible for the survival of tardigrades in extreme conditions.”
The scientists chose Saccharomyces cerevisiae yeast. Yeast is the simplest model of a eukaryotic cell, which is used in research, including on various issues related to humans. As for tardigrade proteins, the researchers decided on alternative oxidase (AOX). This enzyme is present in the mitochondria of plants, but also in some invertebrates, including nematodes, annelids and tardigrades. It provides an alternative way of transferring electrons from ubiquinone to oxygen. Unlike the typical cytochrome oxidase found in mitochondria and responsible for the respiratory chain, alternative oxidase is independent of inhibitors such as cyanide. Small amounts of cyanide in humans block cellular respiration. In the case of alternative oxidase, they do not block it, so cells can continue to function properly. Such a gene has been introduced into yeast. This yeast, together with a control group, i.e. yeast that does not have this gene, will be sent to the International Space Station to test how the new yeast strain will cope with microgravity and radiation.
The full name of the project is: ‘Before we fly to Mars: Can tardigrades help other organisms survive in space?’ By creating yeast that is more resistant to space conditions than ordinary yeast, scientists want to create a strain that could be used in the future as, for example, a biofactory for food during long space missions or at various types of bases that humanity plans to build in the future on the Moon and other planets, and which could also be a source of fuel.
Before this happens, however, there are many problems to be solved. One of them is definitely radiation. Yeast has not yet been studied in this regard. That being said, tardigrades have been studied from this angle, and we know that in a state of anhydrobiosis, i.e. in a dried state, exposure to radiation does not cause any changes. Tardigrades wake up and live. It is alternative oxidase that is one of the proteins responsible for tardigrades entering a state of anhydrobiosis. Scientists hope that it may also protect yeast cells from radiation.
Tardigrades are like space pirates. They can survive very high and very low temperatures. As long as they do not encounter water and are in the form of so-called barrel cysts, i.e. in an anhydrobiotic state, they can survive for up to several decades. Tardigrades also cope very well with freezing and can function normally after thawing.
Preparation of yeast | Photo by Prof. Andonis Karachitos
Prepared yeast | Photyo by Prof. Andonis Karachitos
Ready for launch
A box containing 40 vials with nutrient medium and inoculated yeast will be transported to the ISS. First, however, everything had to be properly packed and sent to Cape Canaveral in the United States. The yeast must be transported at a low temperature (approx. 4°C) to prevent it from multiplying prematurely and using up the nutrient medium before the experiment begins. In orbit, Sławosz Uznański-Wiśniewski, PhD will be responsible for launching the experiment: transferring the vials from the refrigerator, monitoring the conditions (temperature, radiation, time in microgravity), and then safely returning the samples to Earth. The entire study set will then return to Earth and to the laboratory, where scientists from the Yeast TardigradeGene project will analyse what has actually come back.
“First of all, we hope that the yeast will survive,” says Izabela Poprawa, PhD, DSc, Assoc. Prof. “After their return, we will see how they managed up there. We will check their viability, i.e. whether they will multiply in the same way as the control group, or perhaps even better. We will also check the functioning of the mitochondria. These are cellular organelles which, in the event of stress, are usually the first to start functioning less efficiently. We want to check whether the conditions on the ISS have caused any changes in the ultrastructure of these cells, i.e. whether the mitochondria have been damaged. If damage has occurred, we want to see whether the cells are able to compensate for it and activate processes that allow them to regenerate or remove damaged organelles and develop healthy ones. Do they activate the autophagy process, which causes the digestion of damaged organelles so as not to destroy the cell? Alternatively, is the process of cell death activated? This is another thing we also have to take into account,” explains the biologist.
The Yeast TardigradeGene project is not only a biological experiment, but also a test of the perseverance and creativity of scientists. The project shows that even the smallest details – from the composition of the yeast medium to the shape of the packaging – matter in space conditions. And the success of this type of mission opens the door to further, increasingly ambitious research beyond Earth.
Yeast ready for the mission | Photo by: Prof. Andonis Karachitos
Yeast prepared for shipment to the ISS | Photo by: Prof. Ewa Szuszkiewicz
Article ‘The gene of space pirates’ will be published in the June issue of USil Magazine No. 9 (329).