Dear Andrew et al.,

While I'm not considered much of a votary of leftist causes, I am compelled
to speak out for the amino acids; in living systems, they are normally
left-handed molecules.

A pal of mine, Ed Picou, a retired paleontologist involved with petroleum
prospecting, showed me that the direction of coil in fossil helical forams
was in some instances an unambiguous stratigraphic marker.  Proper
attention to sinistral or dextral chirality of these creatures can make the
difference between finding a gusher of black gold or drilling a dry well.

At 06:58 AM 1/5/2005, you wrote:

Dextral and sinistral isomers, mirror-image molecules. Identical
chemical properties and chemical formulae. Our bodies can process
dextral isomers but not sinistral isomers of the same compounds.
Sugar? Sinistrose, anyone? ...........

>  However, mollusks are relatively unusual in having many kinds that
>are normally distinctly asymmetric.  Many forminifera have
>snail-like coiled shells; these can be sinstral or dextral, too.

Foram handedness is temperature-controlled, with no genetic
component, and is unrelated to gastropod coiling. Indeed, the
organisms (currently in kingdom Protists, so they are not animals or
"creatures") themselves are basically "amorphous" blobs of protoplasm
& organelles. I wonder how they manage to secrete such regular and
beautiful shells?

>--
>Andrew Grebneff

Harry G. Lee
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