castor-oil seeds
Ricin occurs naturally in the seeds of the castor oil plantCreative Commons

 Only a few milligrams of ricin -- one of the most poisonous substances in the world, is enough to kill a human. But, a young man in Germany is immune to the substance which can shut down our central nervous system, kidneys, liver and other organs if we inhale, ingest, or inject it.

20-year-old Jacob is a patient at University Hospital Münster in Germany. He has been in the hospital since the time he was born in 1997, as 'there was always something wrong with his health'; his mother told a German press agency DPA.

Scientists say that he has an extremely rare genetic defect which prevents him from metabolizing the sugar fructose but it also means that he is immune to ricin poisoning.

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At present, there is no clinically-tested antidote but Jacob may offer clues as to how one could be developed. The worse thing is, naturally occurs in the seeds of the castor oil plant.

Once the poison enters the body of a human, it binds to sugar molecules which are attached all over our body cells' surfaces.

"It becomes a problem as soon as ricin binds to receptors, which constantly turn over between the outside and the inside of a cell," Johannes Stadlmann, a researcher at the Institute for Molecular Biotechnology at the Austrian Academy of Sciences in Vienna, told Deutsche Welle.

Stadlmann added: "With the receptors' help, ricin gets transported into the cells."

At present no antidote exists. However, a German patient at University Hospital Münster in Germany may offer clues as to how one could be developed.

So far, mice experiments have been conducted by Stadlmann. The experiments showed that ricin immunity can be induced by injecting a fructose inhibitor temporarily. However, it is yet to be seen whether it applies to humans as well or not. But, the research might one day lead to the development of a true antidote.