Index >>Viroids and Prions >>Prions

Prions -  Prusiner and his associates of the University of California at San Francisco have discovered an organism which appears to contain no genetic material of its own.
This organism, called the prion, is 100 to 1000 times smaller than the smallest organism, and would thus be the smallest of living things.
The existence of prions is at present speculative.
The relationship between prions and some diseases is based only 6n negative evidence.
If their existence is established; they might prove to be a new form of life.
Prusiner and his colleagues discovered the prion while studying scrapie, a fatal disease, of the nervous system of sheep.

The prion may consist of just a single or two ar three protein molecules.
Since it multiplies, it may be relying an the nucleic acid present in host cells.
It should be noted that certain viral particles like the tap particles of multipartite plant viruses do not contain any nucleic acid, and would thus appear to be similar to prions.
Such tap particles are, however, Non infective by themselves, and do not show any biological activity. Moreover, they are much larger than prions.
Thus prions are quite distinct from top particles.
Prions have also been implicated in other diseases such as senile dementia, multiple sclerosis, amytrophic lateral sclerosis, (Lou Gehrig disease) and Parkinsons disease.