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

Being Riptup brewhaha at freenet.edmonton.ab.ca
Mon Jul 31 04:25:20 EST 2006


Dr Engelbert Buxbaum wrote:
> 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.

A prevalent genetic appendix? One found in mice, Elk, and felines.
If you don't mind my saying so, I think that conclusion is hard to
support, implying as it does that every test ever performed (and a
great many that haven't been) on mice has been performed on prion-free
mice.

What little I know of PrP, that it seems to be copper activated,
sujests to me that it might be involved in inflammation. Some time ago,
my mother's nursing textbook told me that Aspirin affected copper
metabolism and probably works by doing so.

That might fit the anti-oxidant theory of normal prion function,
somehow. Part of the immune system is _based_ on free radicals.
Inflammation is an immune response, and it seems appropriate for the
body to defend itself from its own immune system. Inflammation
localizes the battle. Perhaps copper serves the dual purpose of
neutralizing free radicals and activating an enzyme that would cause
swelling when the copper is oxidized.

So, I guess it might be worth studying whether these prion-free mice
are less apt
to exhibit inflammation from an injected allergen.

> >
> > <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.

I was expecting to find some figures about it under TSEs. That seems to
be where this informaiton belongs. I also hav difficulty believing that
DNA encodes anything but the sequence of amino acids, so even if
someone found a mutation that was more prone to exhibit disease
characteristics, it wouldn't be prevalent.

> > 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".

"Skeptik" is more neutral. I think the dissenting view is already at a
disadvantage for having two levels of indirect cause to explain or
show. As the edition currently stands,
explanations of the evidence are deleted. I think a virus would've been
isolated and printed by now, however small. I guess it's good not to
rule anything out, and I don't think a virus is a big enough likelihood
to chase.

> 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.

The surjikal instrument vector is too much of a case history for me. Of
course,
wiki can get to a size that would be expensive to print, so that
doesn't mean
the information won't fit into a deep article.



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