Here\u2019s what you\u2019ll learn when you read this story:<\/p>\n
As bacteria become increasingly (and worryingly) resistant to antibiotics, scientists are recruiting bacteriophages\u2014a bacteria\u2019s sworn evolutionary enemy\u2014to fight against these troublesome \u201csuperbugs.\u201d<\/p>\n
In a new study, scientists analyzed how this biological battle played out between a strain of Escherichia coli (E. coli) and a T7 bacteriophage, both on Earth and in the microgravity environment aboard the International Space Station (ISS).<\/p>\n
While the bacteria and the phage evolved differing strategies depending on the environment, the phage developed mutations that increased their ability to bind receptors on a bacterial cell, which could benefit human health on Earth.<\/p>\n
The largest battle in biological history plays out across the Earth\u2019s surface everyday, mostly unseen from human eyes. Bacteria, and their nemeses, bacteriophages<\/a>\u2014viruses that can infect specific bacteria and replicate inside them\u2014battle one another, instigating an evolutionary \u201carms race\u201d where each combatant tries to genetically outsmart the other. Hundreds of billions of bacteriophages live inside your gut, and these biological entities (not lifeforms<\/a>, as they\u2019re technically not alive) far outnumber all living organisms on Earth.<\/p>\n In the 21st century, thanks to the orbiting lab known as the International Space Station<\/a> (ISS), this multi-billion-year-old biological arms race is now playing out in microgravity, and a new study published in the journal PLOS One<\/a> shows that the battle tactics differ between the ground and space. Because bacteriophages may be our best line of defense against antimicrobial resistant (AMR) bacteria, understanding this difference could create more effective ways to combat AMR superbugs, which the World Health Organization (WHO) identified as a top threat<\/a> to global public health.<\/p>\n \u201cPhages act as major drivers of bacterial diversity and evolutionary change in their bacterial prey,\u201d the authors wrote in the study. \u201cAlthough phage\u2013host interactions have been extensively studied in terrestrial ecosystems, the impact of microgravity on these interactions has yet to be fully investigated.\u201d<\/p>\n To fill in this knowledge gap, the research team (led by scientists at the University of Wisconsin-Madison) analyzed two bacterial samples of Escherichia coli<\/a> (E. coli)\u2014one located on Earth, the other on the ISS, and both infected with what is known as a T7 bacteriophage. Eventually, they found that while the outcome of the arms race remained the same in each location\u2014the bacteriophage eventually infected its bacterial prey\u2014there were distinct differences in how this battle played out between the two samples.<\/p>\n The team used whole-genome sequencing<\/a> and deep mutational scanning to get a full picture of this bacterial battle. As it turns out, in space, the bacteriophages were slower to infect bacteria than they were on Earth, but they still accumulated mutations that increased their ability to bind receptors on bacterial cells. Meanwhile, the bacteria developed novel mutations that specifically protected against phages in microgravity conditions.<\/p>\n \u201cSpace fundamentally changes how phages and bacteria interact: infection is slowed, and both organisms evolve along a different trajectory than they do on Earth,\u201d the authors wrote<\/a>. \u201cBy 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.\u201d<\/p>\n