Why bacteria survive in space—biologists discover clues

What is it about?

Microorganisms can find their way onto and into stuff that gets sent into space, even though care is taken to clean spacecraft prior to launch. Thus, bacterial spores from Earth might ride piggyback on spacecraft. This paper reports the findings from comparing the genomic blueprint of spore producing Bacilli that survive the harsh conditions of spacecraft cleanroom facilities with the genomes of similar organims that are not from such environments.

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Why is it important?

Bacteria survive and have been carried onboard the International Space Station and found on the Mars Rover. The ability of bacteria to survive extreme conditions could potentially lead to a process called 'forward contamination.' The search for life elsewhere is impacted by the possible transport of organisms from Earth to solar system bodies of interest. Bacterial spores appear to be finding ways to escape decontamination and understanding what makes these spores so special at their genomic level helps us relate these features with their ability to evade decontamination measures. The team studied non-pathogenic (non-disease-causing) bacteria that belong to the genus Bacillus and produce highly resistant spores. They were isolated from cleanrooms and spacecraft assembly facilities at the Jet Propulsion Laboratory. The complete genome of two strains resistant to peroxide and radiation: B. safensis FO-36bT and B. pumilus SAFR-032 were sequenced. And compared with that of bacteria known to produce spores that are vulnerable to peroxide and radiation, such as the strain B. pumilus ATCC7061T. The genome blueprint gives the basic clues of what the organism might be harboring. By comparing the blueprints of the, 10 genes were found that are unique to the FO-36b, that are not found in any other organisms (including other Bacillus strains). That is 10 genes whose functions are unknown—or 10 suspects for why spores of B. safensis FO-36bT are resistant to peroxide and radiation, although it is not immediately obvious that the presence or absence of any specific gene or combination of genes is responsible for the variations in resistance seen. These are potential genes of interest with respect to the resistance of the spores of this strain. Four of these genes are found on phage elements of the bacterial strain. Phage, short for bacteriophage, is a virus that infects bacteria. Phages are major facilitators for transferring genes between microbes.

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