A little knowledge can be a dangerous thing. But more often than not, a lack of knowledge is even more dangerous. In Europe, cattle have always been fed with meat and bone meal, made from butchered cows and sheep. In nature, canibalism is rarely practiced, as it increases the risk of becoming infected with the parasites of your dead companions, but farms tried to obviate this risk by boiling the meat at temperaturs known to kill most organisms. What nobody knew at the time was that diseases can also spread through agents that aren't organisms. Meat farmers learned this the hard way, when 157 people died of a variant of Creutzfeldt-Jakob disease from eating beef infected with mad cow disease, caused by a misshapen prion.

Prions are proteins that can adopt different forms, and which can convert other prions into their own forms, like zombies in a horror film infecting the living. The word "prion" is short for "proteinaceous infectious particle" (with the letters scrambled around a bit), as it is predominately seen as an agent of disease. But according to this news article, prions may also play a more positive role, faciliating memory:

Rapid folding of the prion-like protein, CPEB, seems to be what the brain uses to "lock in" memory traces. In other words, we need it to fold.

According to biologist Susan Lindquist at the Whitehead Institute for Biomedical Research outside Boston, under normal circumstances the folding protein forms a long chainlike structure that seems to help nerve cells "” neurons "” solidify connections with each other, maintaining memory. This finding, she said "is an exciting and revolutionary thing."

This phenomenon, if shown to be widespread, would add an interesting layer to the adaptability of eukaryotes. Many responses to the environment (such as the "fight or flight" response) involve the activation of genes to make the appropriate proteins, but a prion-mediated signal can spread quickly, without any new molecules having to be produced. Furthermore, prions can be inherited in their active shape through the cytoplasm, raising the spectre of Lamarck. But what's even more interesting is that "CPEB acts much the same and can transmit inherited information in yeast, without needing genetic material, meaning DNA or RNA." If an organism as distantly related to us as yeast uses prions, it raises the possibility that we are dealing with a system of considerable age.

Thanks to reader Bilbo for directing my attention to this story.

This entry was posted on Saturday, May 20th, 2006 at 1:48 pm and is filed under Biology, Evolution. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site. The trackback link is: http://telicthoughts.com/prions-and-memory/trackback/