Nuclear Powered Bacteria

[Mr Skeptic]

They found a bacteria in water 3 km below a South African gold mine. It seems this organism is alone there or nearly so (composing 99.9% of the DNA from the sample), rather than a diverse community as might be expected anywhere else. And apparently, it is powered (indirectly) by the decay of uranium. As such, this is a truly unique bacterium.

 

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

http://www.theallineed.com/ecology/08102005.htm

http://www.sciencemag.org/cgi/content/abstract/322/5899/275

 

This bacteria seems to suggest that life could occur in environments we might never have expected.

[NeonBlack]

Very cool. But I thought I remembered reading about a mushroom or some type of fungus near Chernobl that did something similar. Has anyone else heard that? I'll have to try to find it again.

[farmboy]

Thats very interesting.

[iNow]

This bacteria seems to suggest that life could occur in environments we might never have expected.

I wonder if we could use these to help us with disposal of our nuclear waste. Cool find.

 

 

 

Very cool. But I thought I remembered reading about a mushroom or some type of fungus near Chernobl that did something similar. Has anyone else heard that? I'll have to try to find it again.

I think it's this one:

 

 

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.

 

Detailing the research in Public Library of Science ONE, AEC's Arturo Casadevall said his interest was piqued five years ago when he read about how a robot sent into the still-highly-radioactive Chernobyl reactor had returned with samples of black, melanin-rich fungi that were growing on the ruined reactor's walls. "I found that very interesting and began discussing with colleagues whether these fungi might be using the radiation emissions as an energy source," explained Casadevall.

 

Casadevall and his co-researchers then set about performing a variety of tests using several different fungi. Two types - one that was induced to make melanin (Crytococcus neoformans) and another that naturally contains it (Wangiella dermatitidis) - were exposed to levels of ionizing radiation approximately 500 times higher than background levels. Both of these melanin-containing species grew significantly faster than when exposed to standard background radiation.

 

"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," said co-researcher Ekaterina Dadachova.

 

Investigating further, the researchers measured the electron spin resonance signal after melanin was exposed to ionizing radiation and found that 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. Until now, melanin's biological role in fungi - if any - had been a mystery. Interestingly, the melanin in fungi is no different chemically from the melanin in our skin, leading Casadevall to speculate that melanin could be providing energy to skin cells.

 

And radiation-munching fungi could be on the menu for future space missions. "Since ionizing radiation is prevalent in outer space, astronauts might be able to rely on fungi as an inexhaustible food source on long missions or for colonizing other planets," noted Dadachova.

 

 

 

And, if it was that one, here's the original study:

http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0000457

Ionizing Radiation Changes the Electronic Properties of Melanin and Enhances the Growth of Melanized Fungi

[NeonBlack]

Yeah! That was it. Nice find, iNow.

[Mr Skeptic]

I wonder if we could use these to help us with disposal of our nuclear waste. Cool find.

 

Thanks. However, it seems that what they actually eat is hydrogen, which can be released when the radiation hits water molecules. So I'd doubt that they'd help with disposal. Still, it's comforting and interesting to know that the sun isn't the only source of energy for life.

[C_Sagan_Returns]

Very cool. But I thought I remembered reading about a mushroom or some type of fungus near Chernobl that did something similar. Has anyone else heard that? I'll have to try to find it again.

 

What is the name of this fungi, the article does not specify?

 

Also, let's not forget about Deinococcus radiodurans...

 

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

 

CSR

[iNow]

What is the name of this fungi, the article does not specify?

 

I guess that depends on which article you read, since that data is contained in the Methods section below:

http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0000457

[CharonY]

Deinococcus radiodurans is radiation resistant, but it does not generate energy.

The names of the fungi are given in iNows post (as is the link to the publication itself). Not to rain onto the parade, however the study only shows that the fungi grew faster if irradiated. They still require all the other nutrients. How the works and whether it is really feeding on the radiation or a more obscure secondary effect, is still unknown.

 

Regarding the bacteria, those mentioned in the OP do not (as already mentioned) directly utilize radiation, however there are bacteria that breathe metals, including uranium, instead of oxygen, for instance (a process termed dissimilatory metal reduction, btw).

 

till, it's comforting and interesting to know that the sun isn't the only source of energy for life.

Well it sure isn't. At least not if you look at bacteria. They have a lot of different means of energy metabolism, of which the above mentioned metal reduction was likely one of the earliest forms of energy generation. In theory this energy could also be utilized for carbon fixation, though few bacteria nowadays actually do that (most likely as photosynthesis is more effective in that regard). However the first bacteria were strict anaerobes so the food chain in that time could not start with photosynthesis.

 

Edit: kind of cross-posted with iNow

Edited January 2, 2009 by CharonY