Prions

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Not all infectious diseases are transmitted by bacteria or [[Virus|viruses]].&nbsp;Some neurological diseases, such as [[Creutzfeldt-Jaakob disease (CJD)|Creutzfeldt-Jaakob disease (CJD)]]&nbsp;or mad cow disease are in fact caused by agents called Prions''', '''which are of similar size to viruses but are made up of only [[Protein|protein]] <ref>J. M. Berg et al. (2007) p 53, Biochemistry, Sixth edition, New York, W.H. Freeman and Company</ref>.&nbsp;These diseases are can be called Prion diseases or [[transmissible spongiform encephalpathies|transmissible spongiform encephalpathies]] (TSE)&nbsp;<ref>http://www.who.int/bloodproducts/tse/en/</ref>.&nbsp;  
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Not all infectious diseases are transmitted by bacteria or [[Virus|viruses]].&nbsp;Some neurological diseases, such as [[Creutzfeldt-Jaakob disease (CJD)|Creutzfeldt-Jakob disease (CJD)]]&nbsp;or mad cow disease are in fact caused by agents called Prions''', '''which are of similar size to viruses but are made up of only [[Protein|protein]] <ref>J. M. Berg et al. (2007) p 53, Biochemistry, Sixth edition, New York, W.H. Freeman and Company</ref>.&nbsp;These diseases are can be called Prion diseases or [[Transmissible spongiform encephalpathies|transmissible spongiform encephalpathies]] (TSE)&nbsp;<ref>http://www.who.int/bloodproducts/tse/en/</ref>.&nbsp;  
  
 
Prionshave these characteristics:  
 
Prionshave these characteristics:  
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#"The protein is largely or completely derived from a cellular protein called PrP, that is normally present in the brain" <ref>J. M. Berg et al. (2007) p 53, Biochemistry, Sixth edition, New York, W.H. Freeman and Company</ref>.
 
#"The protein is largely or completely derived from a cellular protein called PrP, that is normally present in the brain" <ref>J. M. Berg et al. (2007) p 53, Biochemistry, Sixth edition, New York, W.H. Freeman and Company</ref>.
  
So an aggregated form of a [[protein|protein]] (that is already present in the brain) is the infectious agent in prion diseases <ref>J. M. Berg et al. (2007) p 54, Biochemistry, Sixth edition, New York, W.H. Freeman and Company</ref>.  
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So an aggregated form of a [[Protein|protein]] (that is already present in the brain) is the infectious agent in prion diseases <ref>J. M. Berg et al. (2007) p 54, Biochemistry, Sixth edition, New York, W.H. Freeman and Company</ref>.  
  
 
The pathalogic mechanism of prions is often associated with structural change. Exogenous prions cause the endogenous host proteins to undergo a structural change, rendering them functionless or harmful.  
 
The pathalogic mechanism of prions is often associated with structural change. Exogenous prions cause the endogenous host proteins to undergo a structural change, rendering them functionless or harmful.  
  
Prions size and structure enable them to resistance to:
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Prions size and structure enable them to resistance to:  
  
*[[proteases|proteases]]
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*[[Proteases|proteases]]  
*heat (not in 100 celsius)
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*heat (not in 100 celsius)  
*radiation
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*radiation  
*fixative treatments ([[formaldehyde|formaldehyde]])
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*fixative treatments ([[Formaldehyde|formaldehyde]])
  
If only the [[Secondary_structure|secondary]], [[Tertiary_structure|tertiary]] and [[Quaternary_Structure|quaternary]] structure is destroy the prion can fold back to the prion after the influence of the substance  
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If only the [[Secondary structure|secondary]], [[Tertiary structure|tertiary]] and [[Quaternary Structure|quaternary]] structure is destroy the prion can fold back to the prion after the influence of the substance  
  
examples of prion disease:
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examples of prion disease:  
  
*[[scrapie|scrapie]] (sheep)
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*[[Scrapie|scrapie]] (sheep)  
*[[Bovie spongiform encephalopathy|Bovie spongiform encephalopathy]] (BSE) [[mad cow disease|mad cow disease]]
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*[[Bovie spongiform encephalopathy|Bovie spongiform encephalopathy]] (BSE) [[Mad cow disease|mad cow disease]]  
 
*[[Kuru|Kuru]] (transmitted by ritual cannibalism)
 
*[[Kuru|Kuru]] (transmitted by ritual cannibalism)
  

Revision as of 20:56, 3 December 2017

Not all infectious diseases are transmitted by bacteria or viruses. Some neurological diseases, such as Creutzfeldt-Jakob disease (CJD) or mad cow disease are in fact caused by agents called Prions, which are of similar size to viruses but are made up of only protein [1]. These diseases are can be called Prion diseases or transmissible spongiform encephalpathies (TSE) [2]

Prionshave these characteristics:

  1.  "The transmissible agent consists of aggregated forms of a specific protein" [3].
  2. These protein aggregates cannot be degraded by the agents that degrade most other proteins [4].
  3. "The protein is largely or completely derived from a cellular protein called PrP, that is normally present in the brain" [5].

So an aggregated form of a protein (that is already present in the brain) is the infectious agent in prion diseases [6].

The pathalogic mechanism of prions is often associated with structural change. Exogenous prions cause the endogenous host proteins to undergo a structural change, rendering them functionless or harmful.

Prions size and structure enable them to resistance to:

If only the secondary, tertiary and quaternary structure is destroy the prion can fold back to the prion after the influence of the substance

examples of prion disease:

References

  1. J. M. Berg et al. (2007) p 53, Biochemistry, Sixth edition, New York, W.H. Freeman and Company
  2. http://www.who.int/bloodproducts/tse/en/
  3. J. M. Berg et al. (2007) p 53, Biochemistry, Sixth edition, New York, W.H. Freeman and Company
  4. J. M. Berg et al. (2007) p 53, Biochemistry, Sixth edition, New York, W.H. Freeman and Company
  5. J. M. Berg et al. (2007) p 53, Biochemistry, Sixth edition, New York, W.H. Freeman and Company
  6. J. M. Berg et al. (2007) p 54, Biochemistry, Sixth edition, New York, W.H. Freeman and Company
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