Re: Could human skin be photosynthetic?

Uncle Al <UncleAl0@xxxxxxxxxxxxx> wrote in news:47067C65.28499B03@xxxxxxxxxxxxx:

[ Mod. Note: Please restrict further comments to relevant physics. -ik ]

billb@xxxxxxxxxx wrote:

I've always thought that, were it possible for biology to harness
ionizing radiation for energy, some organism would already have done
so. The ground contains vast fungal and bacterial communities, but
also contains "light sources" in the form of uranium ore deposits.

Well, it looks like my suspicions were correct:

Inside the Chernobyl reactor: fungus feeds on radiation
http://www.wtnrradio.com/news/story.php?story=262

But there's more... Apparently the fungus uses an unsuspected
photosynthetic molecule: melanin. It's not green like light-loving
plants, instead it's brown and eats gamma rays.

What other organism deals with hard radiation and employs the melanin
molecule? People?
[snip]

The cited article is sensationalist not technical.

The original is available for comment at PLoS-One:

<http://www.plosone.org/article/fetchArticle.action?articleURI=info:doi/10.1371/journal.pone.0000457>

or <http://tinyurl.com/yp73eg> for the word-wrap happy news clients.

How will you couple incoming energy to biochemistry, specifically
production of sugar or ATP?

From their abstract:
---------
Methodology/Principal Findings

Ionizing irradiation changed the electron spin resonance (ESR) signal of
melanin, consistent with changes in electronic structure. Irradiated
melanin manifested a 4-fold increase in its capacity to reduce NADH
relative to non-irradiated melanin.
-----end snippet----------

I would quibble that NADH _is_ the reduced form of NAD. I assume they
meant that the capacity to reduce NAD was enhanced. If you can reduce
NAD, you can make sugar.

--
David Winsemius

.

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