SETI bioastro: FW: [NSS-Discuss] Venus-bound spacecraft: An idea from the gut

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From: Larry Klaes (
Date: Wed Jun 13 2001 - 13:11:35 PDT

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Subject: [NSS-Discuss] Venus-bound spacecraft: An idea from the gut

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If anyone is interested in designing instruments that would survive the
of the Venus atmosphere, appended below is a wild longshot area of inquiry
from yesterday's New York times: creating shielding from molecules in the
shape of h.pylori bacteria's urease enzyme. (O the joys of lay ignorance.)

Date: 06/12/01 9:07:42 AM Central Daylight Time

Secrets of a Survivor

     The bacterium Helicobacter pylori never ceases to amaze. Two decades
ago, to the surprise of many, it was found to be the major cause of stomach
ulcers. Perhaps half the world's population is infected by it, and it is the
only known bug that is able to survive in the harsh acidic conditions of the

     Now researchers in South Korea have discovered a secret to H. pylori's
survival: It takes a circle-the-wagons approach.

     H. pylori produces an enzyme that converts urea found in gastric juices
into ammonia. The ammonia, in turn, neutralizes the acidity of the gastric
juices in the immediate vicinity of the bacteria, creating a safe
microenvironment for the micro-organism.

     One puzzle for scientists has been to determine how the enzyme, urease,
can itself survive all that acidity. The Korean researchers, reporting in
Nature Structural Biology, have now shown how it is done by uncovering the
enzyme's crystal structure.

     Unlike other bacterial versions of urease, the type produced by H.
pylori is unique in that it has a spherical shape, with a cavity in the
middle. What's more, the enzyme's 12 active sites are all toward the middle.
This structure, the researchers suggest, offers protection from the
acid, allowing the enzyme to work on the urea in relative peace.

     The researchers say that their work may help in developing treatments
for pylori-induced ulcers. Making urease more vulnerable to stomach acid,
for example, would mean less ammonia, and thus less protection for the

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