Chernobyl Fungus Feeds On Radiation (2007) | Hacker News Reader

Chernobyl Fungus Feeds On Radiation (2007)

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99 pointsskennedy53 comments

So following up later papers that cite the original [1] doesn't seem like this has gone very far. A number of papers collecting extremofile exemplars, and a few thinking about energy sources. But nothing on 'space food', 'radioactive remediation', or analysis of the energy source in humans. Sigh.

[1] http://scholar.google.com/scholar?cites=14704617567455474393...

The problem is that the active molecule itself has a complex structure, and it is very hard to get a high-resolution image of even one of its structures (melanin can be folded in lots of ways). There's some potential for better imaging with fairly recent discoveries in partial-wavelength resolution microscopy using weak-measurement, but it's still a new technology. Melanin's mechanism for absorbing ionizing radiation, if understood, will definitely open up major applications for a perfected, synthesized solution.

So, radiation is a big risk factor in sending astronauts to Mars and around the solar system.

What if we could genetically engineer ourselves to use this melanin pathway for ourselves?

We wouldn't use energy from radiation in the fungi-melanin pathway (although we could), but it could be good to make our bodies recognize that a radiation storm is happening and that could trigger biochemical changes in our bodies. Either to become more radiation proof (hide yo' DNA in chromatin) or take some radiation-resilient actions (heavily increase the reproduction of cells in our gut lining).

This isn't a very realistic idea, just a sci-fi thing. We have a hundred years of ethics and technology to accomplish before this would be realistic.

>>So, radiation is a big risk factor in sending astronauts to Mars and around the solar system. >>What if we could genetically engineer ourselves to use this melanin pathway for ourselves?

I had a friend in high school who was really good at biology and wanted to pursue a career in genetics.

I asked him why and he said he wanted to design humans that have tiger claws.

I think his dream is more realistic than what you suggest. :)

We already have melanin in our skin to block radiation though, don't we?

We have melanin in our skin to block radiation from the sun. Now there's a difference. The sun is emitting thermal radiation of about a million degrees celcius. The energy profile of it's radiation is very well studied. It's basically random radiation with every individual photon being in a defined (and quite low) energy interval.

Radiation in space is totally random over the entire spectrum. There aren't many events at all (compared to the sun's radiation you could be forgiven for claiming there isn't any radiation in space at all, so few photons), but the events that do happen have a totally random energy distribution. Meaning most of the rays have enough energy to knock 2 or 3 molecules from the front of your finger into your brain. Or (a very tiny) part of the casing of the ship into deep into your body. If you measure space radiation with your sensor pointed down towards this massive rock we're living on, using the entire mass of the planet to block the radiation, the meter does not go down to zero (even when you eliminate the radiation produced by the planet itself).

Metals have a bit of an advantage blocking radiation because they have collective electron orbitals. If radiation impacts an electron inside a metal structure, it's going to throw it centimeters, meters away, maybe even kilometers. But here's the difference : that energy can be dissipated all around the structure. In other words, just because an electron gets an energy boost and gets thrown all around the room does not mean it has left it's orbital at all, and so it should remain inside the metal plate. If it does, the radiation is blocked. It's a sort of "structural integrity" field : the energy delivered does not have to beat the magnetic field of a single atom, but the magnetic field of the entire lattice. Unfortunately, on a per-atom basis, metal magnetic fields are on the very low side (mostly).

Ideally you'd use compressed plasma clouds to block radiation. But the energy required for maintaining that is rather enormous. But it would block pretty much all radiation (this is the reason the early universe, despite producing more photons in essentially empty space than the fusion reaction in the sun does today, was "completely dark". Those photons couldn't travel, so they'd never hit any sensor)

This is the problem with space radiation. Once radiation energy levels go above certain "reasonable" energy levels blocking it becomes a pipe dream.

"If you measure space radiation with your sensor pointed down towards this massive rock we're living on, using the entire mass of the planet to block the radiation, the meter does not go down to zero (even when you eliminate the radiation produced by the planet itself)."

Can you explain this further? Wouldn't it suggest that we're exposed to the same radiation while on Earth?

It's not that the atmosphere does not protect us. Just not 100%, which shows just how much energy (a tiny fraction of) these particles have. So yes, you get a few atoms in your body blown off by a cosmic ray once every few months or so. In space you can expect that to increase to several times per second (as compared to solar rays, which of course constantly hit).

This was a statement meant to illustrate that so far we haven't really found an upper bound for the energy levels of these particles. Give a particle enough energy and it'll fly right through the planet.

http://en.wikipedia.org/wiki/Cosmic_ray

The interesting thing is that we don't actually know where most of these rays come from (about 1 in 100 million comes from a supernova/black hole/other known powerful event). So something is pretty much everywhere in space, shoots out particles like a particle accelerator, except much more powerful than the ones we can build. Yet whatever is doing this manages to avoid detection by any other means.

From what I understand of this, the fungus basically "eats" radiation in the sense that plants eat sunlight, but that only prevents the radiation from damaging the fungus to the extent that the radiation hits the melanin instead of hitting the DNA or whatever.

So if you made a human that did this, you would have a human that could refrain from eating much food for energy and instead choose to hang out in a nuclear reactor (they would still need to eat to take in nutrients, but would need fewer calories I guess?) ...but they'd also still get radiation poisoning / cancer / etc.

Also, it isn't clear to me how these could be used to "clean up" messes anymore than sunbathers could clean up the sun. It seems they just absorb gamma rays, but nothing about them doing that should make that material decay faster... Maybe the idea is that they intake the radioactive particles and consolidate them so that cleanup then entails finding the fungus (which is presumably easier to visually locate) and scooping it all up? Maybe you could engineer the fungus to also bioluminescence strongly to aid in this.

Likelihood of cancer may be related to the general chance of reproductive mutation, and the chance of reproductive mutation is also likely to be something that changes through evolution.

If you have a species in a high-radiation environment, is it not possible that it evolves to have fewer reproductive mutations in general - and therefore lower chance of cancer?

Yes, I think it makes sense that certain arrangements of DNA would be less susceptible to going cancerous than others. In one strand you might have a possible '1 bit flip' (I'm not a biologist in the slightest) change that would turn the routine into "while(1) {fork();}", but perhaps in another functionally equivalent strand you would need to flip 2 or 3 bits to get the same effect.

So basically you want to select for DNA that has a large (DNA equivalent of) Levenshtein distance to cancerous DNA. Perhaps that is something that you could even deliberately engineer (though I don't think a general solution is possible since determining if DNA is cancerous might be the halting problem?)

Maybe it would be easier to construct a strand of DNA that has the same effect as another strand of DNA, but with more error-checking. Throw in a bunch of asserts or something to send cells with DNA that fails the error checking into suicide mode...

In practice, I suspect that we have numerous ways of dealing with mutations. However, if I recall my high-school biology correctly, during DNA replication there is error correction. My guess would be that evolution would tend to regulate mutations rates through the efficiency of error correction mechanisms (and the accuracy of the primary duplication mechanism) more so than a meta-evolution in the structure of DNA. Having said that, it is reasonable that there would be evolutionary pressure to have DNA that requires more mutations before becoming dangerous.

Responding to the content of your post. DNA is not executable code as much as data. The 'primary' purpose of DNA is to provide the blueprints for proteins. DNA sequences can be thought of in by grouping the base pairs in 3 called codons (this grouping is not reflected in the molecular structure). The beginning and end of a gene are marked by "start" and "stop" codons, which are just a specific DNA subsequence. Conceptually, a gene is converted into a protein by replacing each codon with its corresponding ammino acid (based on a lookup table) [1]. The function of a gene is determined by the chemical properties of the resulting protein.

As it turns out, there are parts of DNA that do not code for proteins, yet still have significant effect. However, I am not aware of any evidence of a naturally occurring use of DNA that resembles executable code.

[1]http://www.biogem.org/codon.jpg

I suppose what I am suggesting is something along the lines of littering the DNA with lots more "stuff that does nothing" that has a very small edit distance from "encodes the creation of a protein that kills the cell."

So while you might normally have:

  ... ACGATTACGATACG ....
  ---|--------------|---
       |
       useful protein

You would now have:

  ... ACGATTACGATACG TACC TACC TACC TACC TACC TACC TACC TACC TACC ...
  ---|--------------|----|----|----|----|----|----|----|----|----|---
       |                |
       useful protein   pointless proteins

The trick with the TACC being that perhaps TAAC, AACC, and TAGC all, rather than encoding a pointless protein, each encode a protein that will kill the cell. Any random damage to TACC will have a high chance of producing a sequence that will be deadly to the cell.

So each time you get whacked by a gamma ray, you spin a die and see what it hits. Maybe it hits a naturally occurring sequence like 'ACGATTACGATACG' and maybe you get cancer. Or maybe it hits one of those artificially inserted TACC segments that is designed to usually break in such a way that the cell is killed. Add more and more TACC segments and you become less and less efficient, but the odds get stacked more in your favor the more you add.

It would kind of be the "electric fence" approach to arresting unintended behavior (http://en.wikipedia.org/wiki/Electric_Fence).

I suspect actually pulling this off isn't something that is doable in the foreseeable future, since it would require being able to make strong statements of the nature "This segment of DNA should have no effect", and similar, but it makes sense in my head at least ;)

That only applies to base likelihood. Radiation adds a whole new level onto that by altering the structure of the DNA when it hits it. You could completely eliminate inheritable chances of cancer but still end up with cancer patients as a result of radiation poisoning,

>If you have a species in a high-radiation environment, is it not possible that it evolves to have fewer reproductive mutations in general - and therefore lower chance of cancer?

IIRC there were studies of Chernobyl cows which showed that in such conditions genotype evolves such way that random mutations have less effects on phenotype, at cost of loss of specialisation.

I found that article, it's in Russian:

http://www.hij.ru/read/issues/2010/may/957/

I read it on elementy.ru:

http://elementy.ru/lib/431228

"So if you made a human that did this, you would have a human that could refrain from eating much food for energy and instead choose to hang out in a nuclear reactor"

There may also be a surface area to volume argument that radiation could support a 200 pound pile of fungi, but only as long as the average thickness of fungus (or human) is less than 1/4 inch for maximum adsorption rate.

Also specific power per gram of fungi is probably pretty low compared to my leg muscles.

It would probably be more efficient to use the reactor to generate (eventually) visible light and use that and good old chlorophyll although that runs into the surface area/volume thing again where extensive past discussion shows all it really does is slow down starvation a couple percent. Chlorophyll is ridiculously inefficient.

That's a good point. Gamma rays are pretty penetrating though, so unlike visible light there might be some benefit to having a rather thick piece of flesh to absorb as much gamma rays as possible, instead of letting most of them pass through the skin then get uselessly absorbed by muscle and organs.

I think you are dead on with the power consumption point though. The human body uses something around 100 watts or so right? (That might just be how much they put off in waste heat, I'm not really sure... but in the neighborhood of a few hundred watts I guess) You would need to put out way more than that in gamma rays to power the person, taking into account waste at various stages. I suspect you'd cook a human before you managed to power one.

I had a strange weird idea about all this, you might not be able to generate enough power to do mechanical stuff, but I wonder if you could power nano-robots and micro power bio-telemetry gadgets using this? The problem with magnetic fields is the area of the pickup coil of something the size of a blood cell is so small.

You couldn't do anything bulk physical, but you might safely generate enough power to do ultra low power telemetry. Like hold this piece of natural granite to activate the glucose monitor sensors in your hand's blood vessels walls or something.

Or using a really good switching power supply like design you could eat a banana, all of which are somewhat radioactive, and some sensor could very slowly charge up for an hour (or a day, or a week...) and then use all that power in a millisecond to squeak out your blood pressure to your phone.

Something good might yet come of this. Probably not this decade, maybe this century though.

If somebody at YC turns this into a startup I'll be impressed.

Sounds a lot like what Nancy Kress explored in Beggars Ride[1]:

"Miranda Sharifi changed this by creating the "Change syringe," a slim black injection that rebuilt the human body to be photosynthetic, able to absorb nutrients from any adjacent biological matter (dirt, grass, clothes, etc.), and resistant against disease, infection, foreign matter and casual injury. Lying on the ground in the sun for half an hour is sufficient "food" for any Changed individual."

[1] http://en.wikipedia.org/wiki/Beggars_Ride

> What if we could genetically engineer ourselves to use this melanin pathway for ourselves?

I can see this being totally feasible, more than the other approach, which would be to engineer ourselves to fix our own DNA:

http://cfpub.epa.gov/ncer_abstracts/index.cfm/fuseaction/dis...

You might be surprised. Genetic engineering of our bodies is not necessary to take advantage of melanin's UV absorbent, antioxidant and radical scavenging properties. There have been a couple of "melanin" pills developed to that end. Of course they don't create energy for the body, though. They have also found it difficult to achieve final regulatory approval.

http://en.wikipedia.org/wiki/Afamelanotide

http://en.wikipedia.org/wiki/Melanotan_II

This is a very cool fungus, I'm glad this was posted! The trickery of its survival comes from its use of melanin, specifically pheomelanin. Basically what happens is when ionizing radiation strikes pheomelanin, an incident electron is generated because of something known as the Compton effect (think photoelectric effect but at really high energy). Somehow, pheomelanin is able to strip down the energy of the electron until it is no longer capable of acting as a free radical and destroying surrounding matter. Unfortunately, that mechanism is still unknown, hopefully with the development of higher resolution microscopes we can get a more thorough understanding of the molecular structure.

This reminds me of the fungus you see growing on the sides of distillery facilities (if you ever go through bourbon country in Kentucky, all the whisky aging warehouses are covered in the stuff). Instead of radiation, they thrive on ethanol.

http://en.wikipedia.org/wiki/Baudoinia_compniacensis

If you're bored and want a story about it: http://www.wired.com/magazine/2011/05/ff_angelsshare/all/1

Interesting. Only 2 photosynthetic molecules are known so far in all branches of life, chlorophyll and rhodopsin, so the existence of another photosynthetic pathway is pretty surprising! I hope it's not another case of hype followed by debunking like for "arsenic dna" or "antideluvian dna".

The study seems to be done properly though, and hints at a possible mechanism, so maybe. I'd need a couple follow up studies of the mechanism to be convinced!

(2007)

Very interesting, though. Just not very new.

Yes, I remembered hearing about it back then. But this does make me wonder if anything new has been found out about how it works. A quick wikipedia/google scholar suggests it hasn't, sadly.

http://en.wikipedia.org/wiki/Radiotrophic_fungus

This is almost out of a Michael Crichton book. So close. http://en.m.wikipedia.org/wiki/The_Andromeda_Strain

I hope this could be cultivated and embedded around sites in Japan.

I am pretty sure I've heard something about Japanese wanting to try radiation "eating" fungi at Chernobyl ago in order to decontaminate the area almost a decade ago.

The fungi can't break down radiation, no known method can do that(1), and probably not even collect it. The amount of radioactivity is unchanged regardless of the presence of these fungi. They only use the radiation that is there as an energy source.

(1) Bombarding with neutrons or high energy charged particles may change the amount of radioactivity. Also, positron-emitting nucleotides can have slightly faster halflife at very low temperatures. None of these methods are available for the fungi.

Melanin has about a 30% absorption rate of ionizing radiation in the gamma spectrum, and remains stable (not oxidized in the traditional rate) while producing a current. The fungus is able to produce an acidic fuel source from the current that it feeds off of. The fungus is definitely breaking down radiation, incredibly, but it's mechanism is very poorly understood.

The fungus is (apparently) absorbing the radiation and using it as an energy source. But it is not making the radioactive atoms decay faster. So the time we have to wait until the area is safe and has a low radioactivity level doesn’t change.

True, but a layer of fungus would presumably act as an insulator, as it's absorbing part of the radiation? Perhaps it would be easier/cheaper/prettier to cover the sarcophagus in the fungus than in more concrete? Depending, of course, on a) how much it actually absorbs and b) how thick you can pile the stuff?

Nah, when gamma photon is absorbed it doesn't matter whether its energy will be used for fungal metabolism or converted to heat right away. And in case of gamma absorption rate mostly depends on mass density, so fungi will be likely as good as water. Concrete not only absorbs more radiation for the same thickness but is far more stable than anything alive.

what about the toxicity of the water as a result of being exposed to radiation, versus the toxicity of the fungi?

I'm not a nuclear scientist, but I can't think of any way pure water may become "toxic" due to exposure to radiation (instead of dissolving radioactive materials, which would definitely be a problem). Maybe excessive neutron radiation could build up tritium, but that already sounds like a stretch. (Most radioactive elements don't emit neutron spontaneously.)

Whoops, you're totally right! I misread the comment I responded to. Melanin is only useful when radiation is emitted. It can't coerce decay to happen more quickly.

You're getting downvoted which is too bad because you're talking about the right plan for the wrong reasons.

Google for the term bioaccumulation. Your body, for example, has serious problems with bioaccumulating radioactive iodine and strontium and a couple other elements. The Japanese plan was to plant fungi that looooove eating cesium and accumulating it in their fungus flesh (well, maybe it wasn't cesium, but you get the idea). Then you scrape up the radioactive, dying fungus into waste barrels and plant some more, and eventually all the bioaccumulative element is in barrels instead of dirt.

There are of course minor engineering issues like how the heck you gather the bioaccumulated plant matter without using humans who will contaminate themselves and die and/or make a bigger mess than just leaving it alone.

There is also a little engineering problem with scale... say you had a major DDT spill which thins poultry eggs killing off wild birds. Well, you could put an industrial poultry fryer farm over the DDT spill and bury the DDT contaminated eggs in the bottom of the ocean, or maybe incinerate them or something to provide cogeneration heat and electricity to run the plant... yeah... it would just take a trillion birds a billion years to clean up a major spill. Other than that minor scaling engineering problem...

http://fukushima-diary.com/2013/06/black-substance-170000-cp...

A black organism that bioaccumulates radionuclides has being known of in Japan for a while.

I wouldn't go so far as to say this is a good or bad thing before we've studied this radioactive monster; considering how very hot it is I'll leave the studying to up someone else...

Funghi absorb radionuclides strongly. The reindeer and other grazers who eat lichen, etc. are all highly contaminated now. Look up radiotrophic funghi.

"Just as the pigment chlorophyll converts sunlight into chemical energy that allows green plants to live and grow, our research suggests that melanin can use a different portion of the electromagnetic spectrum - ionizing radiation - to benefit the fungi containing it,"

One problem with that. Ionizing radiation is not on the electromagnetic spectrum. It's particles with rest mass.

According to the infallible Wikipedia ionizing radiation can refer to either electromagnetic radiation or massive particles.

http://en.wikipedia.org/wiki/Ionizing_radiation

I should have looked that up, huh? :-)

Would be awesome if this could be developed as a method to decontaminate or stabilize areas affected by nuclear accidents.

So the fungi essentially absorbing some of the radiation and transforming it.

Does this mean that this is positively affecting the radioactive halife of the area because the fungi are essentially living off the excesses radiation present and will help contribute to reduce the radiation levels over time?

No. Just like shining a flashlight on a traditional plant doesn't make the batteries wear out any quicker or slower.

However, every gamma it adsorbs, is, well, adsorbed. Its probably not a very good shield compared to sandwiches of iron and water, but its probably better than empty air. Perhaps in the future you could grow a reactor core using a tree. This would make a good minecraft mod.

If it were very aggressive about growth, maybe it would physically block rainwater from hitting the contaminants and running off contaminating downstream. Rainwater hitting harmless fungus and flowing away would help, a little.

I can't quite tell if you are trolling me, but I'll assume for the best as I am truly curious on this.

To take your analogy the torch will loose battery at the same rate but with the plants leaves receiving more light it would be less light that goes in the face of the person standing behind the plant. Do the plants absorbing radiation lead to less radiation being around to be absorbed by humans and animals instead? Maybe I am fundamentally misunderstanding something here.

radiation adsorption occurs at an atomic level too fast for anything chemical to happen WRT the adsorption, so a peculiar arrangement of atoms can't have any effect on overall shielding levels other than bulk density (like how much "stuff per inch" depends on what stuff is). The hack of the system is the very peculiar arrangement of atoms for this specific fungi can make productive use of the gamma energy which most living things can't do. From a nuclear standpoint long after the gamma is ancient history the chemistry can get started (theres a big timescale mismatch). A plain old mushroom or any ole biomass will block the gammas as effectively as this one. Of course a plain old mushroom or biomass can't live in that location; nothing to eat.

It would be like building a firewall that acts like any other firewall, except under DDOS conditions it uses a whole network of diodes and stuff to store up the electrical energy of each attack packet. This doesn't work with routers because they take maybe "hundreds of watts" to run but the received laser power might only be "hundredths of watts". For a fungi that grows slow enough and has no competition in its niche, gammas are apparently enough.

Older news: "Exotic Underground Bacteria Thrive On Radiation Rather Than Sunlight"

http://www.scienceagogo.com/news/20060919234956data_trunc_sy...

Amazing, I guess its easy forget life on earth is billions of years old and extends deep into the planets crust. It has adapted to some completely different environments than what we normally associate with life.

This isn't really "new" but still pretty interesting.

EDIT: Title changed.

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