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When scientists launched bacteria‑infecting viruses to the International Space Station, they discovered that space changes the rules of infection. In microgravity, viruses still attacked their bacterial hosts, but both organisms evolved along strikingly different paths compared to Earth.
The study, led by Phil Huss of the University of Wisconsin‑Madison and published in PLOS Biology on January 13, found that genetic mutations reshaped how viruses latch onto bacteria and how bacteria defend themselves. These changes could open new avenues for phage therapy — a promising tool against drug‑resistant infections.
A Different Kind of Arms Race
On Earth, phages and bacteria are locked in an evolutionary “arms race”: bacteria evolve defenses, while phages adapt to overcome them. But aboard the ISS, microgravity altered bacterial physiology and the physics of collisions between viruses and cells, disrupting familiar patterns.
To probe these dynamics, researchers compared E. coli samples infected with the T7 phage — one set incubated on Earth, the other in orbit. After an initial delay, the space‑station phages successfully infected their hosts. Yet genome sequencing revealed distinct mutations in both bacteria and viruses.
Mutations in Orbit
Phages in space accumulated mutations that enhanced their ability to bind bacterial receptors, potentially boosting infectivity. Meanwhile, E. coli developed mutations that strengthened resistance and improved survival in near‑weightless conditions.
Using deep mutational scanning, the team examined changes in the T7 receptor‑binding protein, a key infection driver. These microgravity‑linked mutations were tied to increased activity against drug‑resistant E. coli strains that cause urinary tract infections — strains normally impervious to T7.
Implications for Health And Exploration
The findings highlight how space research can yield insights with direct benefits back on Earth. By studying space‑driven adaptations, scientists identified ways to engineer phages with superior activity against stubborn pathogens.
“Space fundamentally changes how phages and bacteria interact: infection is slowed, and both organisms evolve along a different trajectory than they do on Earth,” the authors wrote. “By studying those space‑driven adaptations, we identified new biological insights that allowed us to engineer phages with far superior activity against drug‑resistant pathogens back on Earth.”
The research underscores the dual promise of space biology: advancing human health while deepening our understanding of life’s adaptability beyond Earth.
