quote:The materials they have found include the molecules uracil and xanthine, which are precursors to the molecules that make up DNA and RNA, and are known as nucleobases. The team discovered the molecules in rock fragments of the Murchison meteorite, which crashed in Australia in 1969.
Talks about a Potassium filter that needs D and L amino acids but uses glycerin as an ambidextrous one instead: "Glycineâ€™s being the only natural amino acid that can play this role helps explain why the potassium ion filters of all organisms are identical."
the google "clip" on this site is intriguing, but requires AAAS sign in to access the article (abstract doesn't mention it) http://www.sciencemag.org/cgi/content/summary/295/5563/2205?ck=nck "But many bacteria and fungi can turn to an alternative system that allows ... it a specific left- or right-handed amino acid or some other compound--to a ..."
and I love these little guys http://en.wikipedia.org/wiki/Magnetotactic_bacteria biological compass bacteria?
quote: The neurotransmitter is an amino acid called D-serine. It's odd, Snyder says, because it differs in structure from any known molecule in its class found in mammals and other higher animals. D-serine is what chemists call a right handed amino acid. Normally, amino acids have atoms that extend from the left side of the molecule. These L-amino acids, as they're called, are the rule in vertebrates, whose biochemistry is set up to deal with these forms.
Some primitive organisms, however, notably bacteria, have a mixture of both L-amino acids and their mirror images called D-amino acids. But to find a D-amino acid in humans, Snyder says, "is unprecedented;" it's the equivalent of finding a Pterodactyl in your local pet shop.
Moreover, unlike dopamine, serotonin or other traditional nerve transmitters, D-serine isn't secreted at nerve cell endings in the brain. Instead, it comes from adjacent cells called astrocytes, which enclose nerve cells in the brain's gray matter like a glove.
The current study adds conclusive evidence to the idea that D-serine -- released from astrocytes -- activates receptors on key nerve cells in the brain. Activating these receptors, called NMDA receptors, has long been linked with learning, memory and higher thought. NMDA receptors are also known culprits in stroke damage in the brain, and have become a focus for anti-stroke research.
So they do exist, and D-amino acids are used (a) by some bacteria and (b) (at least one anyway) by humans.
But at the Institute for Creation Research in northwest Dallas, a group of nine Ph.D.s from places like Harvard and Los Alamos National Laboratory say all that molecules-to-man stuff is nonsense. And they’re out to prove it.
Let us know when they have results.
The universe is not 13.8 billion years old (as astrophysicists calculate by measuring the rate of cosmic expansion), the earth is not 4.5 billion years old (as geologists conclude by using radioisotope dating on ancient rocks), and humans did not split from chimpanzees and gorillas about 4 million to 7 million years ago (as suggested by genetics and the fossil record).