When you buy through links on our articles, Future and its syndicate partners may earn a commission.
Scientists brought bacteria and phages, i.e. viruses that infect bacteria, aboard the ISS to study their evolution. . | Credit: International Space Station (dima_zel/Getty Images); E.coli (Shutterstock)
Bacteria and the viruses that infect them, called phages, are locked in an evolutionary arms race. But that evolution takes a different trajectory when the battle takes place in microgravity, a study aboard the International Space Station (ISS) shows.
As the bacteria and phages eliminate, the bacteria develop better defenses to survive, while the phages develop new ways to penetrate these defenses. The new study, published Jan. 13 in the journal PLOS Biologydetails how that fight plays out in space and reveals insights that could help us design better drugs for antibiotic-resistant bacteria on Earth.
In the study, researchers compared populations of E. coli infected with a phage known as T7. One set of microbes was incubated aboard the ISS, while identical control groups were grown on Earth.
Analysis of samples from the space station showed that microgravity fundamentally altered the speed and nature of phage infection.
While the phages could still successfully infect and kill bacteria in space, the process took longer than it did in samples on Earth. IN A previous studythe same researchers hypothesized that infection cycles in microgravity would be slower because fluids do not mix as well in microgravity as they do in Earth’s gravity.
“This new study validates our hypothesis and expectations,” said the study’s lead author Srivatsan Ramanassociate professor in the Department of Biochemistry at the University of Wisconsin-Madison.
On Earth, the fluids of bacteria and viruses inside are constantly stirred by gravity—warm water rises, cold water sinks, and heavier particles settle to the bottom. This causes everything to move and bump into each other.
In space, there is no commotion; everything floats. So, because bacteria and phages weren’t bumping into each other as often, phages had to adapt to a much slower pace of life and become more efficient at grabbing passing bacteria.
Experts believe that understanding this alternative form of phage evolution could help them develop new phage therapies. These emerging treatments for infections use phages to kill bacteria or make germs more vulnerable to traditional antibiotics.
“If we can learn what phages do at the genetic level to adapt to the microgravity environment, we can apply this knowledge to experiments with resistant bacteria.” Nicol Caplina former astrobiologist at the European Space Agency who was not involved in the study told Live Science in an email. “And this may be a positive step in the race to optimize antibiotics on Earth.”
Whole-genome sequencing showed that both bacteria and phages on the ISS had accumulated distinct genetic mutations not observed in samples from Earth. Space viruses accumulated specific mutations that enhanced their ability to infect bacteria, as well as their ability to bind to bacterial receptors. Simultaneously, the E. coli they developed mutations that protected them against phage attacks—by modifying receptors, for example—and improved their survival in microgravity.
Next, the researchers used a technique called deep mutational scanning to examine changes in proteins that bind viral receptors. They found that adaptations driven by the unique cosmic environment can have practical applications at home.
When the phages were transported back to Earth and tested, space-adapted changes to their receptor-binding protein resulted in increased activity against E. coli strains that frequently cause urinary tract infections. These strains are usually resistant to T7 phages.
“It was a serendipitous discovery,” Raman said. “We didn’t expect that [mutant] the phages we identified on the ISS would kill pathogens on Earth.”
RELATED STORIES
— Antibiotic found hiding in plain sight could treat dangerous infections, early study shows
— How quickly can antibiotic resistance evolve?
— Antibiotic resistance renders once-lifesaving drugs useless. Could we reverse?
“These results show how space can help us improve the activity of phage therapies,” he said Charlie Moan assistant professor in the Department of Bacteriology at the University of Wisconsin-Madison, who was not involved in the study.
“However,” Mo added, “we have to consider the cost of sending phages into space or simulating microgravity on Earth to get these results.”
In addition to helping fight infections in Earthbound patients, the research could help lead to more effective phage therapies for use in microgravity, Mo suggested. “This could be important for the health of astronauts on long-term space missions – for example, missions to the Moon or Mars or extended stays on the ISS.”