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 (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-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;  
  
 
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 (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&nbsp;
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Prions size and structure enable them to resistance to:
  
-proteases  
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*[[proteases|proteases]]
 +
*heat (not in 100 celsius)
 +
*radiation
 +
*fixative treatments ([[formaldehyde|formaldehyde]])
  
-heat (not in 100 celsius)
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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
  
-radiation
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examples of prion disease:
  
-fixative treatments (formaldehyde)
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*[[scrapie|scrapie]] (sheep)
 
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*[[Bovie spongiform encephalopathy|Bovie spongiform encephalopathy]] (BSE) [[mad cow disease|mad cow disease]]
if only the secondary , tertitry and quaternary structure is destroy the prion can fold back to the prion after the influence of the substance
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*[[Kuru|Kuru]] (transmitted by ritual cannibalism)
 
+
examples of prion disease
+
 
+
-scrapie (sheep)  
+
 
+
-Bovie spongiform encephalopathy (BSE) mad cow disease  
+
 
+
-Kuru (transmitted by ritual cannibalism)  
+
  
 
=== References  ===
 
=== References  ===
  
 
<references />
 
<references />

Revision as of 04:11, 23 November 2015

Not all infectious diseases are transmitted by bacteria or viruses. Some neurological diseases, such as Creutzfeldt-Jaakob 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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