Related Experiment Videos
The effects of microgravity on induced mutation in Escherichia coli and Saccharomyces cerevisiae
A Takahashi1, K Ohnishi, S Takahashi
1Department of Biology, Nara Medical University, Kashihara, Japan.
Abstract:
We examined whether microgravity influences the induced-mutation frequencies through in vivo experiments during space flight aboard the space shuttle Discovery (STS-91). We prepared dried samples of repair-deficient strains and parental strains of Escherichia (E.) coli and Saccharomyces (S.) cerevisiae given DNA damage treatment. After culture in space, we measured the induced-mutation frequencies and SOS-responses under microgravity. The experimental findings indicate that almost the same induced-mutation frequencies and SOS-responses of space samples were observed in both strains compared with the ground control samples. It is suggested that microgravity might not influence induced-mutation frequencies and SOS-responses at the stages of DNA replication and/or DNA repair. In addition, we developed a new experimental apparatus for space experiments to culture and freeze stocks of E. coli and S. cerevisiae cells.
Insights
Microgravity did not significantly alter induced mutation frequencies or DNA repair responses in Escherichia coli and Saccharomyces cerevisiae during spaceflight. Space-flown samples showed similar results to ground controls, suggesting no impact on DNA replication or repair.
Area of Science:
- Astrobiology
- Microbiology
- Genetics
Background:
- Understanding the effects of spaceflight on biological systems is crucial for human space exploration.
- Previous research has explored various spaceflight factors on cellular processes, but the impact of microgravity on induced mutation frequencies requires further investigation.
Purpose of the Study:
- To investigate the influence of microgravity on induced mutation frequencies and SOS responses in bacterial and yeast strains.
- To assess whether DNA replication and repair mechanisms are affected by spaceflight conditions.
Main Methods:
- In vivo experiments were conducted during the STS-91 space shuttle mission.
- Repair-deficient and parental strains of Escherichia coli and Saccharomyces cerevisiae were exposed to DNA damage treatment.
- Cultures were maintained under microgravity, and induced mutation frequencies and SOS responses were measured and compared to ground controls.
Main Results:
- No significant differences were observed in induced mutation frequencies between space-flown samples and ground controls for both Escherichia coli and Saccharomyces cerevisiae.
- SOS responses, indicative of DNA damage and repair activity, were also comparable between microgravity and ground conditions.
- A novel experimental apparatus for culturing and freezing microbial stocks in space was successfully developed.
Conclusions:
- Microgravity does not appear to influence induced mutation frequencies or SOS responses in the tested strains at the stages of DNA replication and/or repair.
- The findings suggest that basic DNA damage and repair mechanisms in these microorganisms are robust under microgravity conditions.
- The developed space-ready apparatus facilitates future in-depth studies on microbial responses to space environments.