Prions
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| − | Not all infectious diseases are transmitted by bacteria or [[ | + | 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: | |
| − | + | #"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>. | ||
| − | + | 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 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: | ||
| + | *[[Proteases|proteases]] | ||
| + | *heat (not in 100 celsius) | ||
| + | *radiation | ||
| + | *fixative treatments ([[Formaldehyde|formaldehyde]]) | ||
| − | + | 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. | |
| + | examples of prion disease: | ||
| + | *[[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 /> | <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:
- "The transmissible agent consists of aggregated forms of a specific protein"[3].
- These protein aggregates cannot be degraded by the agents that degrade most other proteins[4].
- "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:
- proteases
- heat (not in 100 celsius)
- radiation
- fixative treatments (formaldehyde)
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:
- scrapie - in sheep
- Bovie spongiform encephalopathy (BSE) mad cow disease
- Kuru (transmitted by ritual cannibalism)
- Creutzfeldt–Jakob disease (CJD)
- Chronic Wasting Disease (CWD) - in deer and elk
References
- ↑ J. M. Berg et al. (2007) p 53, Biochemistry, Sixth edition, New York, W.H. Freeman and Company
- ↑ http://www.who.int/bloodproducts/tse/en/
- ↑ J. M. Berg et al. (2007) p 53, Biochemistry, Sixth edition, New York, W.H. Freeman and Company
- ↑ J. M. Berg et al. (2007) p 53, Biochemistry, Sixth edition, New York, W.H. Freeman and Company
- ↑ J. M. Berg et al. (2007) p 53, Biochemistry, Sixth edition, New York, W.H. Freeman and Company
- ↑ J. M. Berg et al. (2007) p 54, Biochemistry, Sixth edition, New York, W.H. Freeman and Company
