Why bacteria survive in space—biologists discover clues

June 27, 2018, University of Houston
In the lab of George Fox, left, Madhan Tirumalai, right, is helping unravel the mysteries of space microbiology Credit: University of Houston

In professor George Fox's lab at the University of Houston, scientists are studying Earth germs that could be contaminating other planets. Despite extreme decontamination efforts, bacterial spores from Earth still manage to find their way into outer space aboard spacecraft. Fox and his team are examining how and why some spores elude decontamination. Their research is published in BMC Microbiology.

To gain access into the uber-sanitized clean rooms at NASA's Goddard Space Flight Center in Greenbelt, Maryland, the world's largest clean room, or the Jet Propulsion Laboratory in Caltech, California, employees pass through a series of lobbies. One, with adhesive floor mats, traps dirt carried on shoes. Another, about the size of an old phone booth, delivers a forced-air shower where dozens of air jets blow away dirt and debris. Only after these sterilization measures can they don the bodysuits, head covers and other disinfected regalia.

And still, 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," said Fox, Moores Professor of Biology and Biochemistry and Chemical and Biomolecular Engineering at UH. Fox is no stranger to microbiology. In the 1970's, along with fellow scientist Carl Woese, he revolutionized the field by discovering that archaea are a separate domain of life.

As with natural selection, the cleaning process inside clean rooms will eventually kill off the weaker bacteria while a stronger strain adapts and is unphased by the cleansers.

"No matter what we do, some appear to be finding ways to escape decontamination," said Madhan Tirumalai, a post-doctoral biologist in Fox's lab. "I'm trying to understand what makes these so special at their genomic level and relate these features with their ability to evade decontamination measures."

It starts with sequencing

The Fox 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.

They sequenced the complete genome of two strains resistant to peroxide and radiation: B. safensis FO-36bT and B. pumilus SAFR-032. Then they compared the genomes of those strains and that of another strain, B. safensis JPL-MERTA-8-2, with bacteria known to produce spores that are vulnerable to peroxide and radiation, such as the strain B. pumilus ATCC7061T. The B. safensis JPL-MERTA-8-2 strain was isolated from the Mars Odyssey Spacecraft and associated facilities at the Jet Propulsion Laboratory and later also found on the Mars Explorer Rover (MER) before its launch in 2004.

"The genome blueprint gave us the basic clues of what the organism might be harboring," said Tirumalai. By comparing the blueprints of the four strains, they found 10 that are unique to the FO-36b, that are not found in any other organisms (including other Bacillus ). 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.

"It is quite possible that distinctions in gene regulation can alter the expression levels of key proteins thereby changing the organism's resistance properties without gain or loss of a particular gene. These are potential genes of interest with respect to the resistance of the spores of this strain" said Tirumalai.

As it turns out, 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.

"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.

Explore further: Team discover how microbes survive clean rooms and contaminate spacecraft

More information: Madhan R. Tirumalai et al, Bacillus safensis FO-36b and Bacillus pumilus SAFR-032: a whole genome comparison of two spacecraft assembly facility isolates, BMC Microbiology (2018). DOI: 10.1186/s12866-018-1191-y

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5 / 5 (3) Jun 28, 2018
Perhaps these researchers haven't thought of this possibility, but BENEFICIAL microbes from Earth (which humans and animals may have adapted to already after millions of years of parallel growth and existence, as well as mutual dependence), could be the ones to prepare planets like Mars for the eventual genesis of human presence, so that the human presence on another planet will have already been set in motion in the form of microbial preparations for the arrival of humans, animals and plants.
It would not be intentional, of course, but a secondary benefit to the future human settlers as the Terran microbes who arrived first will colonise the planet as the Martian environment adapts to the presence of the stowaway beneficial microbes.
1 / 5 (1) Jun 28, 2018
S_E_U Are you advocating that we engage in deliberate genocide of alien biomes? Yah gotta stop relying on comicbooks for your science education!

Now back to the article. First, Outer Space is outside the Van Allen Belt & in zero gravity. There is no verified evidence of Earth life surviving for more then a few weeks in those conditions. (the manned Moon landings)

Even if it is inadvertent that a probe to Mars or the asteroids is contaminated? Discovering that it survived such harsh environments for several years? Could determine what extreme safety procedures will be needed for probes landing on Enceladus and Titan.

If it is definitively proven that Earth Life cannot survive out there? We may yet avoid obliterating the very discoveries we were hoping to make. Improves the odds that actual non-earth life may be found. That does not mean we should let ourselves get sloppy about protective procedures.

Jun 28, 2018
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5 / 5 (3) Jun 29, 2018
That seems to be the belief these days, that the potential for Life itself came from outer space on comets and other interplanetary or interstellar space vehicles. But certainly, all of the elements that go into creation of life forms were, and are available on Earth already and had been available when the Creator gave life to the first one-celled life forms about a billion years ago.
That reminds me...I wonder how the Tesla convertible is doing out there in orbit. Did Elon Musk have it decontaminated first before launch so as not to offend rrwillsj? Again he forgets about the Tardigrades.
1 / 5 (1) Jun 29, 2018
Speaking of the pseudoscience of the Panspermia cult.... I just cannot stop laughing! You think "Oh! THEY can't get any stupider then THAT!" And bye golly! THEY keep proving that YES! THEY CAN!

As for those cuddly little critter tardigrades? I remember years ago seeing an experiment exposing a variety of bugs to heavy doses of radiation. Contrary to popular expectations, cockroaches only survived up to about ten thousand roentgens? The surprising winner at surviving a dosage of 100 thousand roentgens of heavy ionizing radiation? Were the Tribolium Flour Beetles. TaDah!

I do not remember if they included tardigrades. Does anyone know if they have been subjected to similar abuse?
1 / 5 (1) Jun 29, 2018
First, Outer Space is outside the Van Allen Belt & in zero gravity. There is no verified evidence of Earth life surviving for more then a few weeks in those conditions
Uh that's because we haven't really looked?

Willis in his profound ignorance seems to think it is more hospitable in these belts than beyond?

"The radiation belts surrounding Earth can become extremely powerful in a matter of seconds, posing much greater risks to communication satellites and spacewalking astronauts than previously believed, scientists said Monday.

"We had thought the radiation belts were a slow, lumbering feature of Earth, but in fact they can change on a knife's edge," said space physicist Daniel Baker of the University of Colorado..."

-Nope, no its not. And yup, your ignorance is verified.
Jun 29, 2018
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Jun 29, 2018
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1 / 5 (1) Jun 29, 2018
ottto dear boy, you know you shouldn't skip your nap after the nurse gives you your medicines. Cause that incoherent rant of yours? Has you arguing against yourself. Have you been belaboring the mirror in your room again?

ZB, now all you have to explain is "HOW" the bacteria got deep inside comets. For aeons of Time, across kiloparsecs of Space. Somehow steering their way across the cosmos to specifically target our proto-Earth. Then survive the blazing entry, smashing through the atmosphere. All the way to the surface. A Bolide would be such a rude ending for any patient voyager.

In addition to pre-arranging that their genetic markers matched those already evolving on this world? And post-arranging to fend off competing genomes for the next few billion years?

ZB, Are you sure you want to be trapped in the quagmire of trying to explain each nit-picking detail of successive success? That it would have taken for such a history to even be possible?

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