Space station mold survives 200 times the radiation dose that would kill a human | Hacker News Reader

Space station mold survives 200 times the radiation dose that would kill a human

sciencemag.org

143 pointslil-scamp36 comments

This is interesting but definitely not surprising by any means.

LD50 for humans is something like 4 Gy. Depending on strain, E Coli have an LD50 of somewhere between 50 Gy and 500 Gy. Deinococcus radiodurans can survive 5000 Gy. Polypedilum vanderplanki can survive 7000 Gy. Various tardigrades will survive 1200-10000 Gy depending on species, state, and type of radiation.

So there are plenty of things that can survive 200 times the radiation dose that will kill a human, including an animal which is known to survive ~2500 times the dose that would kill a human.

Home Depot also carries spray that only causes me mild irritation but absolutely slaughters mold.

What makes them more "radiation-proof" than us?

I don't know about the other organisms but in the case of Deinococcus, the answer is multiple redundant backups of its genome, combined with extremely robust DNA repair machinery.

Exactly. "Space station mold survives 200 times the radiation dose that would kill a human" is as pointless a statement as "Human survives 200 times the amount of caffeine that would kill a hamster."

Radiotrophic fungi are growing inside Chernobyl nuclear power plant and use radiation as alternative source of energy for a process similar to photosynthesis. REF: https://en.wikipedia.org/wiki/Radiotrophic_fungus

HN discussion[1] about why plants do not get Cancer was interesting to me and somewhat related to this story on mold.

So I guess my question is, is there a mold that would be beneficial to have grow in such a confined environment? I assume the ventilation system can filter out the spores, are astronauts by way of the enclosed environment subject to more exposure to spores than on Earth or are the numbers much lower by volume?

https://news.ycombinator.com/item?id=20321463

Fungi are not plants though. Fungi are actually more closely related to animals than plants [1][2]. Plants not getting cancer is irrelevant when talking about cancer rate in mold/fungi.

[1] https://en.wikipedia.org/wiki/Opisthokont [2] https://en.wikipedia.org/wiki/Eukaryote

If you're suggesting that having these types of organisms around would benefit humans by absorbing harmful radiation, it wouldn't work that way.

Is there a reason why this is nonsensical? It seems reasonable with the right properties. If there were some sort of organism that would attract to radiation and grow around, perhaps that could be at a significant enough size that it actually absorbs significant radiation providing protection.

You can get the same effect much more easily by shielding with water.

If you're asking about useful things to grow, hypothetically, we could process CO2 into O2 using plants. However, at our current level of technology I rather suspect it would require a lot more space than the space station has, because we couldn't pack the requisite infrastructure in a very tight space right now.

In Vernor Vinge's "A Deepness in the Sky", where ramships travel at sub-light speeds between the stars in the story, they use algae (IIRC, if not that some other similar thing, as opposed to big plants) to process CO2. The process doesn't just run in one big vat, though; it has to run in multiple partitions, because it's a routine event that a mutation in a particular partition manages to work out how to more efficiently convert the provided resources into reproduction, at the cost of putting out less O2 or putting out other undesirable gasses. It's a routine maintenance job for them to look at the output, take some gene sequence samples, and dump & sterilize sub-par partitions and restock them from the other cells.

I give this as an idea of the potential problems we'd face right now. Even if the tech to do that is a routine design job today, it's still not something we have (AFAIK) and would need time to be tested, and the result would be, as I said, quite bulky for some time (for instance, if you work out the necessary volumes, IIRC it's not like you get "20 cc of algae per astronaut" or some similarly dainty value; it takes quite a bit of algae to put out enough oxygen for our high-energy metabolisms).

Now being discussed at https://news.ycombinator.com/item?id=20342750 (which I happened to see first).

Might be worth combining threads.

Could fungi be used as shielding?

Everything old is new again. I remember reading articles about the mold and fungus trapped in laminated window layers on Mir. The fear then, was that we were creating virulent super-strains.

Is it possible that organisms could adapt to the extreme environment in space and then get returned to earth with bad consequences for us?

This was my first thought as well. Although that adaptation wouldn't be much of an advantage anymore once the organism got back down here. Or would it...

It would if its adaptations would manage to convert nuclear energy into usable energy

You mean create an organism we can then burn to produce electricity?

Unlikely. There are many orders of magnitude more ways to be well adapted to one environment than to be adapted to two or more environments. So if an organism is well adapted to high radiation it’s probably terrible at many, many other things that are irrelevant where it is now. There are plenty of extremophiles apart from these radiophiles. You don’t see microorganisms adapted to very high levels of acid, pressure, heat, cold or anything else suddenly exploding into new ecological niches regularly.

Consider the analogy to multiply resistant to antibiotics bacteria. They’re far more common in hospitals than elsewhere because hospitals are swimming in antibiotics. Once they leave the hospital environment they’re paying a cost to be antibiotic resistant with far lower benefits so they either lose the capacity or are outcompeted by other organisms in the same niche.

The explosion into a new niche does happen occasionally, when a new capacity is extremely useful or when an adaptation is discovered that is far more efficient but has similar costs or better than the alternative. I’m not familiar with any examples in microbiology but invasive species exist and so do we so we have existence proofs in macroorganisms.

In general organisms create bad consequences when they're too adapted to Earth and reproduce excessivly in some way. If they die out because they're adapted to space instead of Earth that won't be a problem for us, though it will be for the organism.

Since Earth is very different from Space, they would be badly adapted to Earth.

So there is very little to worry about from alien world infections.

And also, incidentally, why most awful diseases come from Africa, and very few from the Americas.

So we are infecting space? Or would that be stretching the similarity to Africa and the Americas?

Well, Space is dead, for one thing :)

I'm guessing we've already accidentally seeded other bodies in space (mars, venus, moon, various asteroids, etc) with life.

NASA has procedures in place to wash their space going equipment with hydrogen peroxide washes. Alas strains of Bacillus pumilus have been shown to survive these washes. I had a chance to work on these strains that had been on the space station in experiments to see how they responded to radiation etc there. The resistance to hydrogen peroxide in this strain is incredible. It was so far past resistant compared to the hardiest bacterial strains in the lab that it was off the charts. Life as they say...always finds a way.

Maybe that's how life on earth began and we would just be continuing the process.

"Life finds a way"

Plant life, mostly.

Or fungi, as in this example. Fungi aren't considered plants because they don't do photosynthesis and are generally more like animals (weak cell walls etc)

I'm a bit confused, regarding why this is considered news. That is, beyond the typical need for sensational headlines.

Humans are, as most animals, highly specialized organisms. Plants and fungi on the other hand, are far more generic in their basic organisation. They generally are more capable of recovering from random localized damage (including, but not limited by, radiation), usually far better than animals. It's a direct result of their evolutionary design.

What might be the only real shocking part in the reporting I've read about this, is that the involved scientist are allegedly surprised about their findings. I'm honestly not sure what to make of that.

I hope it's just a product of bad reporting, because otherwise it should raise serious questions about the state of scientific knowledge/education. Maybe I just missed something. I hope it's not just cynical abuse of ignorance, in a hunt for more funding. Still, it feels weird, that with only high school education on this matter (30 years ago) and a little common sense, none of this sounds even remotely strange or surprising to me.

I‘m not familiar enough with the matter, but I think UV light, radiated everywhere every once in a while, should deal quite well with most pathogens.

> Cortesão also found that the spores survived large amounts of high-energy ultraviolet radiation, which is commonly used as a hospital disinfectant and has been proposed for sterilizing the surfaces of spacecraft.

A possible solution could be to spray with water first. Maybe water with sugar, fecula or something that would encourage the fungus to end the spore part of its cycle.

And then shooting with UVA rays.

I love the scientific-y calculus of “stupid amounts” in any context. It’s always fun to see a sense of humor and people having fun with their work.

And thus we created the protomolecule...

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