### substance | particle:

Prion
* accumulate in the brain where they trigger symptoms.
* also are heat resistant.
* are a form of virus that are basically abnormal clumps of proteins
  - newly recognized group of disease- causing agents
  - also impervious to cooking and radiation
  - birds
  - conformational misfoldings of a normal protein
  - different than bacteria or viruses
  - diseases
  - extremely resistant to both heat and chemicals
  - hard to stop
  - harmless molecules unless they get twisted out of their normal shape
  - highly virulent and resist standard sterilization procedures
  - indeed responsible for transmissible and inherited disorders of protein conformation
* are infectious agents that consist of a single type of protein molecule
  - forms of proteins
  - protein particles
* are infectious proteins that can replicate unlike viruses that contain nucleic acids
  - convert the proteins of their hosts for their own purpose
  - without genes of their own
  - much smaller than viruses
* are nearly impossible to destroy
  - indestructible
* are normal proteins in the body
  - of neurological tissues in mammals
  - organic matter
* are protein crystals that grow in grain fungi
  - molecules which have two metastable states
  - proteinaceous infectious particles that lack nucleic acid
* are proteins that all humans possess in their normal form
  - are mis-folded
  - cause infectious diseases
  - occur in the brains of all mammals so far studied
  - resistant to conventional sterilization techniques
  - responsible for causing kuru and other similar diseases
  - rogue proteins that wreak havoc in the brains of infected animals and people
* are sensitive to organic solvents, but can survive boiling and many disinfectants
  - protein denaturing agents, such as phenol and urea
  - smaller than viruses, and there is currently no cure for prion-related diseases
  - stable conformations of proteins which differ from the native folding state
  - structurally altered versions of small proteins that are normally expressed in cells
  - the infectious agents in the disease
  - truly very unusual infectious agents
* are very heat resistant
  - resistant ot fixatives and even heat
  - sensitive to proteases
* can also misfold on their own accord and give rise to disease
  - change for the worse over time
  - even remain infectious on correctly sterilized surgical instruments
* cause proteins normally found in the brain to twist into an abnormal shape
  - scrapie and other spongiform encephalopathies of animals and humans
* consist entirely and exclusively of PrP protein.
* contain no nucleic acid and are therefore different from any other infectious disease.
* diseases an evidence-based protocol for infection control.
* exist in yeast, without harming it
  - normally as innocuous cellular proteins
* have an extraordinarily unique physical properties.
* induces normal PrP to misfold, forming another prion.
* is resistant to freezing, drying and heating at normal cooking temperature.
* keep their shape even if boiled, steamed, hammered, and autoclaved for hours.
* lack a detectable genome.
* normal protein found in the brain.
* protein-only infectious particle which is devoid of nucleic acids.
* reproduce in the tissues of the immune system, including the tonsils.
* stands for pro teinaceous in fectious particles.
* withstand normal steam sterilization and use of disinfectants.
* work by changing the shape of proteins in the living things it causes disease in.
+ Anfinsen's dogma: Molecular biology :: Proteins
  * Prions are an exception to Anfinsen's dogma. Prions are stable conformations of proteins which differ from the native folding state. Other amyloid diseases, including Alzheimer's disease and Parkinson's disease, are also exceptions to Anfinsen's dogma.
  * Prions cause many forms of encephalitis, or brain disease, such as scrapie, Creutzfeldt-Jakob Disease, kuru, and Bovine Spongiform Encephalopathy, also known as Mad Cow Disease. Prions work by changing the shape of proteins in the living things it causes disease in. While normal proteins have lots of alpha helices, or twisted parts, changed proteins have lots of beta sheets, or flat parts. The word is pronounced 'pree-on'.
  * Prions are structurally altered versions of small proteins that are normally expressed in cells. Unlike diseases that are caused by a mutation of the gene resulting in the expression of a mutant protein, prions are able to replicate and transmit diseases through physical contact with the normal proteins resulting in a structural change from the normal to state to the prion state.
+ Infection: Infectious diseases :: Microbiology :: Parasitism
  * Some diseases are caused by 'infection'. Infection is when another organism gets into a person's body and causes harm. These four kinds of infectious agents cause most infectious disease. There are other kinds though. Prions are a form of virus that are basically abnormal clumps of proteins. We are not even sure that prions are alive. But they act just like other infectious diseases.