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Posted by Bob on May 27, 2007, 12:26 pm
Please log in for more thread options wrote:
>EXO LIFE
>Radiation-Eating Fungi Could Change The Energy Balance On Earth And
>Beyond.
>Findings could trigger a recalculation of Earth's energy balance and
>help feed astronauts.
>by Staff Writers
>New York NY (SPX) May 23, 2007
>"Scientists have long assumed that fungi exist mainly to decompose
>matter into chemicals that other organisms can then use. But
>researchers at the Albert Einstein College of Medicine of Yeshiva
>University have found evidence that fungi possess a previously
>undiscovered talent with profound implications: the ability to use
>radioactivity as an energy source for making food and spurring their
>growth."
>http://www.spacedaily.com/reports/Radiation_Eating_Fungi_Could_Change_The_Energy_Balance_On_Earth_And_Beyond_999.html
The paper on which this news story is based is
Ionizing Radiation Changes the Electronic Properties of
Melanin and Enhances the Growth of Melanized Fungi
Ekaterina Dadachova1,2*, Ruth A. Bryan1, Xianchun Huang1, Tiffany
Moadel1, Andrew D. Schweitzer1, Philip Aisen3, Joshua D. Nosanchuk2,4,
Arturo Casadevall2,4
It is freely available at the Plos One web site.
http://www.plosone.org/article/fetchArticle.action?articleURI=info%3Adoi%2F10.1371%2Fjournal.pone.0000457
Anyone who is seriously interested in the issues raised here should
read the paper, and not rely on the simplified version, including
hype, of a news release.
> This could mean interplanetary and interstellar transport of
>microorganisms is possible.
> One of the arguments against life being transferred between planets
>or between star systems is that they could not survive for the many
>years in space unprotected from space radiation.
>This argument becomes invalid if the microbes could actually live on
>radiation.
There is no relationship between the possible use of the radiation for
energy and resistance to the radiation. That is made clear in the
paper.
The levels of radiation used in the paper are very low, and not
generally considered particularly harmful.
> Note as well this could make possible life in the interior of comets.
>One explanation for the aqueous minerals seen in carbonaceous
>meteorites and for the carbonate found on Comet Tempel 1 is that
>liquid water was produced in comet interiors early in the solar
>systems history from radiogenic heating. However, the argument went
>such radioactivity would have been enough to kill any life within the
>comets. This argument also becomes invalid if the life could live on
>this radiation.
Again, that is directly refuted by the paper.
The interesting question is whether the fungi actually use the
radiation as an energy source. The results are intriguing. There does
seem to be some stimulation of growth by the radiation. However, there
is no direct evidence that the stimulation is due to use of the
radiation as energy source -- at least in any conventional bio-energy
sense. For example, the radiation might be causing some breakdown of
some cellular reserves, which can be used for growth. In fact, this is
consistent with their point that the Melanin strain grows more poorly.
I may have missed it, but I don't think the authors claim that the
radiation energy is being used directly for growth.
bob
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