Bacteriophages in Space: Microgravity Gives Rise to Unseen Viral Ingenuity

Even in the near-weightlessness of space, bacteriophages – viruses that infect bacteria – retain their ability to target host cells. Scientists reached this conclusion by studying the interaction of the T7 virus and Escherichia coli aboard the International Space Station (ISS). On Earth, bacteriophages and bacteria are in a constant evolutionary race: bacteria develop defenses while viruses find ways to overcome them. These processes are well-studied under normal conditions, but microgravity alters both bacterial physiology and the physics of virus-cell collisions. There has been little data on how exactly this influences infection dynamics so far.

The authors compared two identical systems: E. coli cultures infected by the T7 phage. Some samples were incubated on Earth, while others were on the ISS under microgravity conditions. Analysis showed that in space, infection did not occur immediately; a delay was observed before the T7 phage successfully infected the bacteria. Additionally, whole-genome sequencing revealed significant differences in accumulated mutations.

Genetic changes in bacteria and viruses developed in microgravity differed markedly from those seen in Earth samples, indicating different evolutionary paths under identical initial conditions. Phages on the ISS gradually accumulated mutations that might enhance their ability to infect bacteria or bind to surface receptors. Meanwhile, E. coli strains in space acquired mutations potentially increasing resistance to phages and improving survival in near weightlessness.

To delve deeper into the mechanisms behind these changes, scientists employed deep mutational scanning – a method that systematically assesses the impact of multiple mutations. The analysis focused on the receptor-binding protein of the T7 phage, which plays a crucial role in the onset of infection. It revealed additional pronounced differences between variants formed in microgravity and on Earth. Further experiments conducted on Earth linked these “space” protein changes to increased phage activity against E. coli strains causing urinary tract infections in humans, which are usually resistant to T7 phage infection.

Overall, the research demonstrates that experiments with bacteriophages aboard the ISS can reveal new patterns in microbial adaptation. According to the authors, microgravity not only delays infection but also steers the evolution of bacteria and viruses down a different path. Understanding these changes has already led to the development of phages with significantly higher activity against drug-resistant bacterial pathogens on Earth – a result important for future space missions and the advancement of alternative approaches to infection treatment.