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Microbes in Microgravity

October 21, 2011

For a change of pace–some real experiments. What happens to microbes in space?

I’ve reviewed NASA grants for bugs in micrograv, and lots of interesting things come out. Some bacteria grow faster in micrograv; and some pathogens get more virulent. Bacteria more readily form biofilms (such as these grown by my student). And antibiotic resistance increases, while human immunity decreases. Companies like Astrogenetix are growing MRSA (deadly drug-resistant staph) aboard the ISS to somehow develop new drugs. (Supposedly the strain is “safe” for the astronauts.)

What kind of experiments do you think they should do on the space station?

  1. Alex Tolley permalink
    October 21, 2011 11:15 pm

    Partial gravity (0.1-.75) experiments on mammals. Impact on physiology.

    Genomic studies on why bugs change their growth patterns. What about algae? Impact of partial g.

  2. October 22, 2011 12:35 am

    Brew beer, starting from barley seeds.

  3. Frances permalink
    October 22, 2011 6:19 am

    Cheese, bread, wine making, and other fermented, mould- and bacteria-ridden consumables (miso and other soy products, kimchi! Things could get smelly though with fermented tofu or shrimp paste).

    Besides being tasty and nutritious, would experiments like this be useful anyway for researching ecosystems rather than microbes in isolation?

    • October 22, 2011 11:52 am

      True. The other thing is that I’m not sure how much experience NASA has in dealing with complex, multi-phase materials in free-fall. Multi-phase means it contains solids, liquids, and generated gas, and obviously having fermentation going means the chemistry gets complex and changes over time.

      There’s three things of interest here:
      1. How do the yeasts (or lactobacillus, or whatever) differ in things like gene expression in free-fall.
      2. How does the bulk process of fermentation differ in free-fall? The sediment doesn’t settle in beer, and the bubbles don’t rise in bread or kimchi. They still exert pressure through gas evolution, so that has to be contained. But can you still make beer, bread, or any other, or do the yeasts and bacteria get stuck in little pockets of depleted resources, starve, and stop the fermentation process prematurely?
      3. Given that you have to work in a pressure vessel, often with a gas seal of some sort, how do you arrange for efficient, accurate sampling of what’s going on inside the fermentation container? For example, beer making classically relies on hydrometer-based densimetry, which relies on gravity to work.

      None of these are insoluble problems, and they get at things (like bubbles in fluid pipes) that bedevil space flight. If we’re aiming for closed ecosystems in freefall, we’ll need a sophisticated understanding of how biological systems break substrates down. Fermented foods are a way to start working on this.

      • paws4thot permalink
        October 24, 2011 7:07 am

        I wonder; could we do this with a centrifuge? Would a wine-making kit (where the yeast reaction is allowed to go to completion {all sugar converted to alcohol or yeast dies of alcohol poisoning}) be worth experimenting with before beer, since that requires SG measurement?

  4. October 23, 2011 1:20 am

    When I was Mission Planning Engineer at JPL for the Voyager encounter with Uranus, I was tasked by CSIRO with calculating the probability that Voyager would miss the flyby by hitting Uranus, or otherwise contaminate the planet with microbes. They did not like my answers, which were uncomfortably high, so the report was taken away and falsified by a 3rd party. They were also alarmed by my worst case scenario, where at an altitude where temperature and water content are right, Uranus could end up with a greater mass of terrestrial life than our own biosphere has.

  5. October 23, 2011 1:34 am

    This just in: New University of Alberta research shows the first evidence that the first oxygen-breathing bacteria occupied and thrived on land 100 million years earlier than previously thought. The researchers show that the most primitive form of aerobic-respiring life on land came into existence 2.48 billion years ago.

    • October 23, 2011 1:49 pm

      Early life geology is fun, so we’ll see how the scientist community sorts it out. More than once my textbook has included “startling new finds” about life three billion years ago, only to have to backpedal it in the next edition. ;)

      Acid mine drainage today certainly does support microbial life, such as Ferroplasma below pH 0 (that’s no typo).

  6. October 23, 2011 1:35 am

    Sorry, forgot the citation:
    Kurt O. Konhauser, Stefan V. Lalonde, Noah J. Planavsky, Ernesto Pecoits, Timothy W. Lyons, Stephen J. Mojzsis, Olivier J. Rouxel, Mark E. Barley, Carlos Rosìere, Phillip W. Fralick, Lee R. Kump, Andrey Bekker. Aerobic bacterial pyrite oxidation and acid rock drainage during the Great Oxidation Event. Nature, 2011; 478 (7369): 369 DOI: 10.1038/nature10511

    • October 24, 2011 9:53 am

      I know about that, but that’s only because my current time travel story is set partially in the Archean. One thing about the “Great Oxidation Event”: it took two billion years. The Great Animal Event that we’re currently in has only lasted about a third as long…

      When it comes to the deepest stretches of our history, we’ve got both astigmatism and near-sightedness, and it really distorts our perception of the time scales involved.

  7. October 24, 2011 11:10 am

    Old age/geriatric medicine. Developing ways for the handicapped to live in space. The effects of living in an enclosed space for a long time. Off the top of my head stuff.

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