[Protein-analysis] Re: http://en.wikipedia.org/wiki/Prion

Dr Engelbert Buxbaum engelbert_buxbaum at hotmail.com
Thu Jul 20 12:52:07 EST 2006


Being Riptup wrote:

> PrPC is found on the membranes
> of cells, though its normal function has not been fully resolved. Since
> the original hypothesis was proposed, a gene for PrP has been isolated:
> the Prnp gene.[8]

One might add here that PrP-knock out mice have been generated and seem
normal in every respect, except that they are not susceptible to
spongiforme encephalopathy. 

> 
> <strike><!-- Relevance: More rare than the prion disease. TSEs are
> subject. -->
> Some prion diseases (TSEs) can be inherited, and in all inherited cases
> there is a mutation in the Prnp gene. Many different prion protein
> mutations have been identified and it is thought that the mutations
> somehow make PrPC more likely to spontaneously change into the PrPSc
> (disease) form. TSEs are the only known diseases that can be sporadic,
> genetic or infectious. For more information, see the article on
> TSEs.</strike>

I would not leave this out, since inherited encephalopathies are not
that rare and shed an interesting light on the PrPc -> PrPsc transition.
In this context it might also be worthwhile to point out that other
proteins show similar transitions in secondary structure, resulting in
Huntingtons and Alzheimers disease.

> Dissent
> The neutrality of this section is disputed.
> Please see the discussion on the talk page.
> 
> Flat Earthers on this topic support the original view that protein does
> not reproduce on its own, nor does it warp other instances of itself.
> Evidence here comes from incinerating the remains of diseased animals.
> This leaves ash and no protein nor nucleic acid. Scientists then feed
> this back to animals to make them exhibit the disease. This leaves no
> organism, much less a pathogen, and since what remains must explain the
> disease, the cause must be an element in excess: an environmental
> poison.

Even the presence of small concentrations of a slow virus are not ruled
out as a cause by some. I would not eliminate these disenting views, but
keep their discussion very short (2-3 sentenses). I would also refrain
from derogative descriptions like "flat earther".

One thing that should be pointed out is the incredible resistance of
PrPsc to destruction, an infected brain remains ionfectious even after
burial for 3 years. This makes sterilisation in the hospital very
difficult. There have been transmissions by surgical instruments and
blood products.


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