Fwd: Hmmm!!!!!

Interesting!!!! Its interesting that I was not able to sign into this site...
Anyways, this gives me a perfect opportunity to test something! Posting through email. Let me see if it works....

Now, coming to the actual post...

Viroids were discovered very recently but they are believed to be present here on earth for as long as life itself! This was because of the fact that some of them exhibit hammerhead ribozyme activity.
They also have interesting way of replicating.......
I came across a mini review of viroids at sciencedirect.com . The paper was published in Febs Letters, volume 567, Issue 1, on 1st June 2004, Pages 42-48 .
Here is the link.

http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6T36-4C8DD9G-2&_user=10&_coverDate=06%2F01%2F2004&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=e491b0abfc3ed8806012a7ad81c01ee2

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Virus - Proteins

Viroids are strange infectious agents. Intriguing and very interesting!

These are nothing but a piece (often a small one) of circular single stranded RNA. These viroids are just 250 to 500 bases long. What makes it interesting is the fact that they like prions defy the concept of cellular organisation!

These RNAs replicate by Rolling circle model of replication.

They are capable of infecting cells and cause diseases.
Many plants diseases are now known to be caused by various viroids.

These are found to exibit catalytic activity as well. Catalyses reactions like forming or breaking covalent bonds.

The only (?) human disease caused by viroids is Hepatitis D...