Chernobyl fungus uses gamma radiation for energy

bascule · September 21, 2007

http://www.scienceagogo.com/news/20070422222547data_trunc_sys.shtml

Researchers at the Albert Einstein College of Medicine (AEC) have found evidence that certain fungi possess another talent beyond their ability to decompose matter: the capacity to use radioactivity as an energy source for making food and spurring their growth.

Insane!

John Cuthber · September 21, 2007

Total bolocks.

**swansont** · September 21, 2007

Total bolocks.

Why? I mean, I agree the article is kind crappy, in the science journalism tradition — no cite of/link to the original work, and not much actual science content ("radiation interacts with melanin to alter its electron structure. This, they believe, is an essential step for capturing radiation and converting it into a different form of energy to make food" ugh. almost science-free) — but why do you disagree?

If you go to http://www.sciencenews.org/articles/20070526/fob5.asp at least there the mention "they found that gamma rays induced a four-fold increase in melanin's ability to catalyze an oxidation-reduction reaction typical of cell metabolism."

The original article is http://www.plosone.org/article/fetchArticle.action?articleURI=info%3Adoi%2F10.1371%2Fjournal.pone.0000457

which I found linked from http://arstechnica.com/journals/science.ars/2007/05/24/gamma-radiation-its-whats-for-dinner

an aside: Blogs seems to do a much better job of citing original articles. I wonder if it's because they aren't defending journalistic turf (i.e. read our magazine and only our magazine)

waitforufo · September 21, 2007

At least for the fungus in question, this may be a case for radiation hormesis.

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

John Cuthber · September 22, 2007

Firstly there is no evidence to support the idea that nuclear radiation is being used by the fungus as an energy source. This is a problem since that's what they are claiming.

Secondly the production of melanin by fungi (and people ) is a defense mechanism against radiation. Not only by directly absorbing the radiation befor it hits anything important (as in the case of a suntan) but also by acting as a free radical trap (which explains the ESR spectum).

All they have shown is that having melanin present is beneficial if you are in a high radiation environement and that's not news because thats exactly why organisms make melanin.

Or, to sumarise, total bollocks.

**swansont** · September 22, 2007

At least for the fungus in question, this may be a case for radiation hormesis.

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

AFAIK 500 times background isn't the appropriate level of radiation for that effect, though maybe for fungus it is.

Firstly there is no evidence to support the idea that nuclear radiation is being used by the fungus as an energy source. This is a problem since that's what they are claiming.

No, what they actually claimed was "Melanized fungal cells manifested increased growth relative to non-melanized cells after exposure to ionizing radiation, raising intriguing questions about a potential role for melanin in energy capture and utilization."

But (from the sciencenews article)

"[They] exposed colonies of C. neoformans to gamma rays 500 times as intense as the normal radiation background on Earth's surface. The colonies grew up to three times as fast as normal. A mutant "albino" form of the fungus, which produced no melanin, grew at a normal pace"

and

"they found that gamma rays induced a four-fold increase in melanin's ability to catalyze an oxidation-reduction reaction typical of cell metabolism"

That sounds like some evidence.

Secondly the production of melanin by fungi (and people ) is a defense mechanism against radiation. Not only by directly absorbing the radiation befor it hits anything important (as in the case of a suntan) but also by acting as a free radical trap (which explains the ESR spectum).

All they have shown is that having melanin present is beneficial if you are in a high radiation environement and that's not news because thats exactly why organisms make melanin.

Or, to sumarise, total bollocks.

If the result was that the fungus grew just fine in a high radiation environment I'd agree that nothing special was going on, but it's growing faster. And, as they point out in the paper, fungi, melanized or not, can withstand higher doses of radiation, so radiation protection is not necessarily why these organisms make melanin.

Sayonara · September 22, 2007

I'd be interested to see how long a fungus grows at an accelerated rate under those conditions.

John Cuthber · September 23, 2007

Hang on.

Have a look at the part of the original post that I described as bollocks.

This bit

"Researchers at the Albert Einstein College of Medicine (AEC) have found evidence that certain fungi possess another talent beyond their ability to decompose matter: the capacity to use radioactivity as an energy source for making food and spurring their growth. "

So I went on to point out that,

"Firstly there is no evidence to support the idea that nuclear radiation is being used by the fungus as an energy source. This is a problem since that's what they are claiming. "

and I get told

"No, what they actually claimed was "Melanized fungal cells manifested increased growth relative to non-melanized cells after exposure to ionizing radiation, raising intriguing questions about a potential role for melanin in energy capture and utilization."

What I should have said was that there was no plausible mechanism proposed. Extraordinary claims require extraordinary evidence.

The plosone article says nothing about catalysis. It does say "Irradiated melanin manifested a 4-fold increase in its capacity to reduce NADH relative to non-irradiated melanin" which might just mean that radiation damaged melanin is more reactive. Big deal.