Prions

prions cause several neurodegenerative diseases in humans and other mammals.prions are proteinaceous infectious agents.they don't have any nucleic acid.this is a unique thing about prions. all the known pathogens like bacteria,viruses and others all have nucleic acid.prions retain their ability to infect even after treatment with ultraviolet radiations or other treatments that destroy nucleic acid.scientists have discovered that prions are the misfolded proteins with abnormal structure .when this abnormal protein binds to same type of normal protein it induce the latter to change its conformation . the newly distorted protein then induces the misfolding in other similar proteins. in this way it become a chain reaction. prions cause mad cow disease also known as bovine spongiform encephalopathy. scientists believe that infected cows may transmit infection to humans .it humans this infection causes CJD that is Creutzfeldt-Jakob disease.the process by which change in structure of protein occur is not clear and research is going on to understand the mechanism .in CJD disease scientists have discovered spongy structure of Brain in dead victims.this sponginess is caused due to holes in brain due to cell death . scientists believe that abnormal shaped protein becomes toxic to cell and causes cell death.prions can be transmitted by eating infected part of victim,by inoculation into brain or skin.some prion cases of CJD and GSS have shown inheritance pattern perhaps this is due to mutation in gene which changes amino acid pattern in a protein and  convert it into a prion.

By:Ashwani, bio- teacher, Phagwara.