Prions

Prions

Prions have been a mistery for scientists from the day they where discovered. Prions act like viruses but they are not. Their structure and chemistry are unknown. They are believed to be proteins but that is yet to be completely proved.

Prion stands for “proteinaceous infectious particles”. Prions are known to cause many diseases involved with nervous systems like the brain. They are the ones that cause the well known “ mad cow ” disesase in Britain and “scrapie” for animals. For humans they are known to cause a rare disease in Papua New

Guinea called Kuru ( or “laughing death”) which striked only the cannibals in the Highlander tribes. Investigation led to the discovery of prions inside the of the victims brains that were eaten by the tribesmen that when they died, as a sign of respect their brains where eaten and the chain went on and on.

The thing that makes prions so special is the fact that they lack the basic elements for reproduction, deoxyribonucleic acid and ribonucleic acid DNA and RNA respectively. This is what has given science a great deal of doubt as this would give the dogma of the beginning of live a radical turn.

Prions have been in research for many years with experiments like the one done by Stanley B. Pruiser and his team of scientists at the School of

Medicine of the University of California at San Francisco in which a study was carried out on mice to see if he was able to purify the scrapie agent ,another prion disease, in mice. But mice as humans took very long to develope the disease, for example Gerstmann-Straussler-Scheinker disease or fatal familial insomnia, which appear mostly on humans which have passed the age of forty and only in very rare cases before, so the experiment was changed to hamsters as these die faster because developed the disease earlier. One of the methods used for this purification process was using a centrifuge, that separates the component of a mixture according to their size and density. After a decade of experiments using the centrifuge method and other chemical methods, several discoveries were made : It was found out that the infectious particles were extremely heterogencous in size and density, the scrapie agent can be found in many molecular forms and the biological activi...

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...stem. Therefore the mutation of the protein may cause disorders in the transmission of the electrical impulses and as it usually happens in old people the replacement of this protein takes very long or it does not take place. When the dead people are opened the brain presents particular symptoms such as non-inflamatory lesions, vacuoles, amyloid protein deposits, astroglios is and gives a spongy appearence to the brain tissue. Most of these diseases are hereditary but some as CJD are known to appear esporadically.

What exactly are prions, we still don’t know, but as knew methods are used for research things appear clearer. Some solutions have appeared for prions, like the hormone manufactured through biotechnology engineering (r-hGH) that stops the transmission of the Creutzfeldt-Jakob prion, but many other diseases may be cured in the future, including Alzheimer’s disease, which affects a great part of population, if it is related to it. As Stanly B. Prusiner said:

If the prion is indeed a single protein and the product of a gene native to the host organism, the time may have come for a reconsideration of what is meant by the concept of infection.