arsenic based life form

[bandwraith at aol.com]

This might help:

   http://www.astrobio.net/exclusive/3698/thriving-on-arsenic

And check out;

  http://www.sciencedaily.com/releases/2010/12/101202140622.htm

The key issue the researchers investigated was when the microbe
 was grown on arsenic did the arsenic actually became incorporated
into the organisms' vital biochemical machinery, such as DNA
 proteins and the cell membranes. A variety of sophisticated laboratory
techniques was used to determine where the arsenic was incorporated.

The team chose to explore Mono Lake because of its unusual
chemistry, especially its high salinity, high alkalinity, and high 
levels
of arsenic. This chemistry is in part a result of Mono Lake's isolation
from its sources of fresh water for 50 years.

The results of this study will inform ongoing research in many areas,
including the study of Earth's evolution, organic chemistry, 
biogeochemica
 cycles, disease mitigation and Earth system research. These finding
  also will open up new frontiers in microbiology and other areas of 
research.

"The idea of alternative biochemistries for life is common in science 
fiction,
  said Carl Pilcher, director of the NASA Astrobiology Institute at the 
agency's
Ames Research Center in Moffett Field, Calif. "Until now a life form 
using
arsenic as a building block was only theoretical, but now we know such 
lif
 exists in Mono Lake."





-----Original Message-----
From: David Morris <fqmorris at gmail.com>
To: malignd <malignd at aol.com>
Cc: pynchon-l <pynchon-l at waste.org>
Sent: Fri, Dec 3, 2010 4:37 pm
Subject: Re: arsenic based life form


First, I'm quoting & linking to the blog post of Dr. Athena Andreas on
the Huffington Post:
http://www.huffingtonpost.com/athena-andreadis-phd/arsenic-and-odd-lace_b_791454.html

She says:
The tables in the Science paper are eloquent on how reluctant even
hardy extremophiles are to use As instead of P. Under normal growth
conditions, the As:P ratio in their biomass was 1:500. When P was
rigorously excluded and As had been raised to three times the level in
lake Mono, the As:P ratio remained at a measly 7:1. Furthermore, upon
fractionation As segregated almost entirely into the organic phase.
Very little was in the aqueous phase that contains the nucleic acids.
This means that under extreme pressure the bacteria will harbor
intracellular As, but they will do their utmost to exclude it from the
vital chains of the genetic material.

But she later updates:
Addendum: Upon re-reading, the paper has evidence that the DNA of the
final isolate contains 11% of the total arsenic by incorporation of
radioactivity and mass spectrometry comparison studies. The crucial
questions are: exactly where is it located, how much substitution has
occurred and how does it affect the layers of DNA function
(un/folding, replication, transcription, translation)? Definitive
answers will require at least direct sequencing and/or
crystallographic data. The leading author, Dr. Felisa Wolfe-Simon,
said that this is fertile ground for thirty years of future work --
and she's right.

So maybe she was being premature?