Stress response of ISS and school isolates for assessment of survival mechanisms across different habitats

Microorganisms exposed to space-relevant stressors, such as microgravity, high levels of ionizing radiation, and desiccation, face distinctive survival challenges. These stressors have the potential to induce physiological and genetic adaptations, which can impact microbial behavior, growth rates, and pathogenicity. For example, a compromised immune system in microgravity environments may facilitate certain microorganisms to become more virulent, thereby posing health risks for astronauts on long-duration missions. Furthermore, space radiation can cause DNA damage, potentially driving the evolution of more resilient strains that could influence microbial communities in spacecraft habitats. Understanding these adaptive responses is critical for developing effective microbial control strategies and ensuring the safety of space missions, especially as humanity plans for prolonged space travel and habitation on extraterrestrial surfaces. Moreover, these insights could inform biotechnology applications on Earth, such as the engineering of stress-resistant microorganisms for industrial or medical use.

Within the study "Touching Surfaces", which tested antimicrobial surfaces in space and on Earth, several microbial isolates were retrieved. The isolates will be tested for their tolerance to key environmental stressors relevant to spaceflight. Stress resistance assays involve exposing microbial samples to X-ray doses simulating cosmic radiation, followed by assessment of cell viability. Desiccation resistance is evaluated by drying the samples under controlled conditions and monitoring recovery upon rehydration. Additionally, the susceptibility of the isolates to antibiotics will be tested.

This study focuses on microbial isolates collected in the "Touching Surfaces" project in both confined environments such as the International Space Station, and everyday settings like German schools. The project aims to evaluate whether these distinct environments yield microbial isolates with differing stress resistance profiles. The central hypothesis being tested is whether isolates from confined and extreme habitats display enhanced resistance towards spaceflight relevant stressors compared to those from everyday environments such as schools.