On Fri, 29 Mar 2002 15:10:21 -0600, "Paul F. Dietz"
<dietz at interaccess.com> wrote:
>"Davin C. Enigl" wrote:
>>> Yet, I read prions survive 1000C for 1 hour, and higher temperatures
>> that would normaly "ash" naked amino acids.
It was actually, 600C for 15 minutes, apparently.
>I seriously doubt prions survive unchanged for 1 hour at 1000 C.
>Perhaps they get converted to a carbonized nanolump that
>has a similar shape and can initiate the same conformational
>chain reaction in the affected proteins.
Here is a experiment that might be of interest:
1) Treatment with formaldehyde before autoclaving stabilized
infectivity, whereas treatment after autoclaving was either inactive
or further reduced infectivity.
2) In additional experiments on specimens (not treated with
formaldehyde) that were subjected to dry heat, a small amount of
infectivity still survived a 1-h exposure to temperatures as high as
360 degrees C.
3) These results are consistent with the operation of a comparatively
primitive molecular mechanism for the initiation of scrapie agent
replication (perhaps an inorganic crystal nucleation step) and the
subsequent participation of an organic macromolecule (scrapie amyloid
protein) that is susceptible to intramolecular cross-stabilization by
[From: J Infect Dis 1990 Mar;161(3):467-72. Resistance of scrapie
infectivity to steam autoclaving after formaldehyde fixation and
limited survival after ashing at 360 degrees C: practical and
theoretical implications. Brown P, Liberski PP, Wolff A, Gajdusek DC.
Laboratory of Central Nervous System Studies, National Institute of
Neurological and Communicative Disorders and Stroke, National
Institutes of Health, Bethesda, Maryland 20892.]