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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 name="null">J. M. Berg et. al (2007) p 53, Biochemistry, Sixth edition, New York, W.H. Freeman and Company</ref>&nbsp;
Not all infectious diseases are transmitted by bacteria or [[Virus|viruses]]. Some neurological diseases, such as [[Creutzfeldt-Jaakob disease (CJD)|Creutzfeldt-Jakob disease (CJD)]] or mad cow disease is 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>. These diseases are can be called Prion diseases or [[Transmissible spongiform encephalpathies|transmissible spongiform encephalpathies]] (TSE)<ref>http://www.who.int/bloodproducts/tse/en/</ref>.


'''Prions '''have these characteristics:  
Prions have these characteristics:  


1.) "The transmissible agent consists of aggregated forms of a specific protein" <ref>J. M. Berg et. al (2007) p 53, Biochemistry, Sixth edition, New York, W.H. Freeman and Company</ref>  
#"The transmissible agent consists of aggregated forms of a specific protein"<ref>J. M. Berg et al. (2007) p 53, Biochemistry, Sixth edition, New York, W.H. Freeman and Company</ref>.
#These [[Protein|protein]] aggregates cannot be degraded by the agents that degrade most other proteins<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>.


2.) These protein aggregates cannot be degraded by the agents that degrade most other proteins <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>.


3.) "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 pathologic 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.  


<br>
Prions size and structure enable them to resistance to:


So an aggregated form of a protein (that is already present in the brain) is the infectious agent in prion diseases <ref name="null">J. M. Berg et. al (2007) p 54, Biochemistry, Sixth edition, New York, W.H. Freeman and Company</ref>
*[[Proteases|proteases]]
*heat (not in 100 celsius)  
*radiation
*fixative treatments ([[Formaldehyde|formaldehyde]])


<br>
If only the [[Secondary structure|secondary]], [[Tertiary structure|tertiary]] and [[Quaternary Structure|quaternary]] structure destroys the prion can fold back to the prion after the influence of the substance.


<br>
examples of prion disease:


== References  ==
*[[Scrapie|scrapie]] - in sheep
*[[Bovie spongiform encephalopathy|Bovie spongiform encephalopathy]] (BSE) [[Mad cow disease|mad cow disease]]
*[[Kuru|Kuru]] (transmitted by ritual cannibalism)
*[[Creutzfeldt–Jakob disease|Creutzfeldt–Jakob disease]] (CJD)
*[[Chronic Wasting Disease|Chronic Wasting Disease]] (CWD) - in deer and elk
 
=== References  ===


<references />
<references />

Latest revision as of 13:36, 25 November 2018

Not all infectious diseases are transmitted by bacteria or viruses. Some neurological diseases, such as Creutzfeldt-Jakob disease (CJD) or mad cow disease is 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].

Prions have 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 pathologic 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 destroys 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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