How do bacteria enter the International Space Station and can be found on the Mars Rover even after it undergoes multiple sterilization treatments at the NASA’s Goddard Space Flight Center in Greenbelt, Maryland or the Jet Propulsion Laboratory in Caltech, California? How can bacteria still be found on the bodysuits and head covers of the astronauts when it goes through the debris and dirt blowers and adhesive mats? Scientists are trying to figure out the same in professor George Fox’s lab at the University of Houston. The research team at Houston is keen to study germs from Earth that could contaminate other planets. The team finds it extremely peculiar that even after such thorough decontamination processes, bacteria still manages to survive and contaminates outer space bound spacecrafts.
This ability of bacteria to push through such extreme conditions and survive could very well lead to the process known as forward contamination. George Fox, Professor of Biology and Biochemistry and Chemical and Biomolecular Engineering at the University of Houston is not someone who doesn’t know what he’s doing- he, along with Carl Woese was the genius behind the revolutionary discovery of archaea as a separate domain of life. “The search for life elsewhere is impacted by the possible transport of organisms from Earth to solar system bodies of interest”, said Fox. It is obvious that it is the stronger bacteria that are able to survive the strong cleaners and the weaker bacterias are killed off easily. “No matter what we do, some bacterial spores appear to be finding ways to escape decontamination. I’m trying to understand what makes these spores so special at their genomic level and relate these features with their ability to evade decontamination measures”, said Madhan Tirumalai, a post-doctoral biologist at University of Houston.
For the research scientists studied non pathogenic bacteria from the genus Bacillus that produce extremely resistant spores that can withstand harsh conditions. These non disease causing bacterias were isolated from the cleaning rooms at the Jet Propulsion Laboratory. They focused on the genomes of two bacterial strains- Bacillus safensis FO-36bT and Bacillus pumilus SAFR-032. Both these strains are resistant to peroxide and radiation. The two strains were then compared with the genomes of two other bacterial strains which aren’t resistant to both peroxide and radiation. “The genome blueprint gave us the basic clues of what the organism might be harboring,” said Tirumalai. After the comparison the scientists found out that some of the resistant strains were present in the phage elements of the strain. It is possible that this might be the reason why decontamination of bacteria from spacecrafts is tough. “The task to eliminate microbes in clean rooms, where spacecraft are assembled, or aboard spacecraft, will continue to be a challenge for NASA and other space agencies,” said Tirumalai.