Not Surprising: Radiated Microbes Evolve In Space

By James Donahue

News of a NASA experiment that exposed the bacteria salmonella to space flight aboard the shuttle Atlantis should not be a surprise. After days of exposure to the radiation of space, the microbes evolved into a more virulent and dangerous strain..

Some of us vividly recall problems the Russians had with runaway strains of mold aboard their 15-year old space station Mur. In the end the mold not only interfered with the electronics but began growing on metal, plastic and glass parts. The problem got so severe we believe it was one of the main reasons Mur was abandoned and allowed to crash into the ocean in 2001.

It was our suspicion that the mold and fungus, as well as other microbes including germs, were being affected and altered by a constant bombardment of solar and other forms of radiation from outer space..

At first response, you might argue that radiation has been found to be an effective way of killing bacteria in food and water before it is packaged and sold in our stores, or delivered via our water taps. While a hearty dose of radiation indeed kills microbes, other forms of radiation, in smaller doses like the kind filtering into a moving space shuttle on the fringes of the Earth's atmosphere, may be zapping these tiny life forms just enough to cause them to evolve into stronger and more resistant strains suitable for space travel.

The effect is much like the evolution of bacteria on Earth after years of assault by a lineup of antibiotics. New and tougher strains are emerging now that our existing battery of medicine cannot kill.

And when it comes to the possibility of extended space travel, the discovery that germs also evolve during exposure to radiation is significant. 

Of all the problems anticipated by NASA and other national space exploration teams in their quest to explore space and perhaps even send a manned mission to Mars, the evolution of a few billion germs and other microbes into a gang of deadly killer bugs was probably not expected.

Consider that during a long trip to Mars, estimated to take at least nine months one-way, and nine-months back, the entire crew might be wiped out by a disease the evolves on the ship and strikes them in mid-flight.

Solar and space radiation also is expected to affect the astronauts, but human evolution involves reproduction and generations of adaptation and change. Germs have a short life span but they reproduce rapidly. Thus change can occur within days if not hours. Humans cannot compete with that.

In the Atlantis experiment, microbiologists at Arizona State University sent tubes with salmonella bacteria on a shuttle flight in September, 2006, to measure the effect space flight would have on a disease-causing microbe. They were shocked to discover that after a few days in orbit, the genetic pattern of the bacteria was changed. What returned was an even more virulent and dangerous form of salmonella.

Writing in the journal Proceedings of the National Academy of Sciences, the professors who conducted the research, Cheryl Nickerson and James Wilson, said they discovered a regulatory protein Hfq appears to be responsible for the enhanced virulence of the bacteria after exposure to space.

The study also found changes in the morphology of the bacteria, indicating the formation of a biofilm not found in the samples grown on Earth. Biofilms also may be linked to the increased strength of the exposed bacteria.