The carcass of a California Happy cow lies at Baker Commodities Inc. The test is positive; it’s infected with Mad Cow disease. This rendering facility preforms tests for animal BSE surveillance programs.
Bovine spongiform encephalopathy (BSE) commonly known as Mad Cow disease is a fatal neurodegenerative disease it causes the spongy degeneration of the brain and the spinal cord.
Mad Cow is a sibling of a series of diseases that spread across species, like scrapies in sheep and Creutzfeldt–Jakob disease in humans. The culprits are prions.
Prions are misfolded proteins. The name is a composition of protein and infection. Now if you remember your biology proteins are composed of a series of bound amino acids, this would be the primary structure then the amino acid arrange themselves in either alpha helix or beta sheet secondary structures, and finally they come together in a 3D tertiary structure.
The structure of a protein is vital, if they change their tertiary or secondary structure they wreak havoc across the body. Protein misfolding is associated with numerous diseases for which no cure is available at the moment. These diseases are often debilitating, as is the case of spongiform encephalopathy.
In 1997, Stanley B. Prusiner won the Noble Prize in for the purifying and identifying the agent accused of transmission of spongiform encephalopathy. Why is discovery worth a Nobel Prize? With a great outbreak of spongiform encephalopathy, in Britain during the 1980, there were numerous investigators searching for the culprit.
Prior these outbreak disease infection diseases were commonly and solely accredited to viruses, bacteria, fungi or parasites. When proteins were first proposed as the wrongdoer there was significant debate against the idea. Few of the scientists at the time considered the possibility; most renouncing the evidence declared that it was impossible.
The first clues that lead biologist Tikvah Alper and mathematician John S. Griffith to suggest a protein was that the disease resisted radiation. Now if it had been in fact a living being (let’s not debate the life of a virus) the pathogen particle would have been destroyed with induced radiation. Their findings also suggested that the pathogen must be smaller than a virus.
Let’s peer into the mechanism of destruction. The name spongiform encephalopathy clearly alludes to a sponge; ence- is the prefix for brain, a spongy brain. The disease spreads and a heap of tiny holes appear in the brain causing mental and physical abilities to deteriorate.
The holes are caused by prions aggregates. The misfolded proteins accumulate outside the disrupting the normal tissue structure and creating the holes. The incubation time is relatively long while the progression is swift and fatal.
Although the full structure of prion has yet to be exposed, researches do know that mammal’s posses correctly folded prion proteins. Once the healthy prions (PrPC) come in contact with misfolded prions (PrPSc) they cannot resist their influence and fold themselves. Following a catalyst reaction of degenerative proteins.
While it is know that eating flesh infected with PrPSc will infect another animal, there are current studies interpreting other possible mechanisms.
One problem is that PrPSc does not respond to sterilization methods like proteases, heat, radiation, and formalin treatments. Effective prion annihilation relies on protein hydrolysis or reduction or destruction of protein tertiary structure with bleach, caustic soda, or strongly acidic detergents.
This is a grim issue when you consider that prions persist in the environment and could possible infect animals roaming once prion infected lands.
A carcass lies in a laboratory bench, researchers probe for answers to number of questions. Are there more reliable quantification methods? Can we denature prions by composting the animal? Could plant uptake prions? Can we prevent it? Can we cure it?