Ricin

At this moment, there is a guy laid up in the hospital in Vegas with ricin poisoning. A stash of ricin has been found in his hotel room/apartment. His dog is dead (not sure why but probably due to lack of water and food) and a couple of other pets are either dead or not doing well (details are blurry).

Details, sketchy as they are, here.

So what is ricin?

Ricin is an extract from castor beans (Ricinus communis). The lethal dose is as little as 0.2 miligrams. That is an amount somewhat smaller than a house fly.

Some creative uses of ricin include the following, cribbed from Wikipedia:

On September 7, 1978 the Bulgarian dissident Georgi Markov was shot in the leg in public on Waterloo Bridge in the middle of London by a man using a weapon built into an umbrella. The weapon embedded a small pellet in Markov's leg which contained ricin. Markov died four days later.

Ouch

In 2003, a package and letter sealed in a "ricin-contaminated" envelope was intercepted in Greenville, South Carolina, at a United States Postal Service processing center.

Very suspicious

In February 2008, A man who stayed in a Las Vegas hotel room where ricin was found was in critical condition at a hospital. The story is still developing as this page is being edited.

Holy crap, Wikipedia is SO current!

How does it work?

Ricin is a potent cytotoxic protein derived from the higher plant Ricinus communis that inactivates eukaryotic ribosomes. ... we have studied the mechanism of action of ricin A-chain on rat liver ribosomes in vitro. Our findings indicate that the toxin inactivates the ribosomes by modifying both or either of two nucleoside residues, G4323 and A4324, in 28 S rRNA. These nucleotides are located close to the alpha-sarcin cleavage site and become resistant to all ribonucleases tested.
[source]

That is not a real current source, but you get the idea. I'll leave it for the biochemical bloggers to explain this in more detail.