Microgravity Exposure Causes Permanent Mutation in Bacteria and Allows Them To Reproduce Faster, Study Suggests

Space travel could permanently mutate Escherichia coli (E. coli) by allowing them to band together and survive. This was discovered by a group of scientists while studying bacteria in a simulated microgravity.

What Is Microgravity?

Microgravity refers to the condition in which humans or objects appear to be weightless. Also known as micro-g environment, its effects can be seen when astronauts and objects float in space.

In this kind of environment, there is always some residual acceleration force, but it is a very small fraction of the full gravity that gives us weight on the surface of the Earth. In short, microgravity does not mean that gravity itself has been reduced, only gravity's effects.

When astronauts are described as being weightless in space, it actually means that they are just experiencing microgravity. There is gravity even in space. It only becomes weaker with distance from the object that exerts the gravitational force. Even if astronauts appear weightless as they get farther away from the Earth, the gravitational pulls from the Moon, the Sun, and other planet will always leave them with a trace of weight.

Permanent Genetic Boost

Scientists from the University of Houston studied the behavior of E. coli cells by monitoring them through 1,000 of growth in simulated microgravity conditions. Compared to previous research, this study is broader in scope as it looks at a much longer trajectory while investigating the entire genome rather than specific subsets of genes.

Experts discovered that the organisms spread significantly faster than a control sample of unaltered bacteria. The test results show that the adapted cells grew about three times as many colonies as the unmodified E. coli. The E.coli cells also demonstrated at least 16 different genetic mutations along the way.

When the supercharged bacteria were removed from microgravity conditions up to 30 generations before testing, 72% of the growth advantage was retained. This shows that the changes prompted by space travel could leave a permanent effect on bacteria.

It is still not clear, though, how these mutations affect their growth rates, either individually or as a group. Although previous studies had not gone to this level of depth or lasted for this long, the researchers had already seen signs that bacteria can breed faster in space.

There are strains that have previously shown to grow 60% more quickly in microgravity. Researchers conclude that there must be something about the weightless environment that favors the microorganisms. Astronauts on board the International Space Station have to deal with thick biofilms of bacteria on their equipment since these organisms are growing faster than normal.

Future research could help experts figure out the kind of bacteria that go along the ride on spaceships, and how they might grow and adapt. If ever modified bacteria make it back down to Earth, scientists would also need to know how to deal with them.

In this study, the researchers reported that the mutated bacteria was killed off just as quickly as normal E. coli then treated with antibiotics. This means that the invasion of supercharged bacteria is still on hold for the time being.