The Final Frontier: Pathogens?

As humanity strives to narrow the chasm between science fiction and reality by traveling in space for longer durations, it continues to be challenged by the health complications associated with microgravity. The side effects of space travel, like muscle atrophy and impaired eyesight, are well documented. While these and similar complications, in addition to logistical difficulties, are serious impediments to our future as a space traveling species, a study published recently in PLOS One now shows how microbes, too, could make long-duration space missions even more challenging.

 

You might not know that bacteria are well-traveled in space, as many bacterial experiments have been conducted in Earth’s orbit since the birth of space travel. From these previous experiments, biologists know that microgravity has several interesting effects on bacteria, such as enhanced biofilm formation, increased virulence, and higher resistance to antibiotics. However, prior to the recently published study, A Molecular Genetic Basis Explaining Altered Bacterial Behavior in Space, scientists lacked sufficient evidence of the mechanics that cause these responses to microgravity.

 

To learn more about what drives these bacterial changes, scientists conducted an experiment to distinguish differences in gene expression between E. coli cultures grown in space and on Earth. When the team of researchers sequenced the RNA of the cultures, they found that the space cultures adapted by upregulating genes associated with acidic conditions and starvation. According to the study, the upregulation of these certain gene groups was caused by the bacteria’s reliance on diffusion and decreased fluid movement. In other words, the space-based cultures showed that food moved into cells and acid moved out of cells more slowly than was seen in the Earth-based cultures.

 

The potential threat to more extensive space travel posed by these results is that some bacterial strains show increased virulence when exposed to acidic environments, which space generated in this study’s E. coli cultures. As such, astronauts may be at risk of facing pathogens primed to spread more easily and capable of doing more damage to humans.