Friday, April 20, 2012

Complexities of a jellyfish sting

Image courtesy Kevin Connors

As the weather gets warmer, many people are beginning to plan for their beach vacations.  But along with the enjoyment of the beach also come hazards such as jellyfish.  Because jellyfish can be very harmful to swimmers it may be difficult to appreciate these sophisticated creatures.  But, the delivery of jellyfish toxin is as amazing as it is dangerous.

Jellyfish toxin isn’t meant to be wasted on human beach goers.  These carnivores are passive feeders, using their tentacles to sting prey like crustaceans, small fish, and plankton.  Jellyfish also sting to defend against their own predators. 

Though jellyfish themselves may not seem that complex, their method of toxin delivery is anything but simple.  Special cells called cnidocblasts house the venomous stinging mechanism.  Within these cells are smaller substructures called nematocysts or cnidocysts, which contain the barb that administers the venom.  Pressure triggers the cnidocblasts to release the coiled nematocyst, piercing the organism that triggered the event, and injecting it with neurotoxin.

Discharged nematocyst

In order to actually engage this spring-like mechanism, cnidocblasts need to utilize many different proteins.  Discharging the nematocyst is very demanding, requiring the cell to endure massive pressure.  Ejecting the harpoon-like barb must also occur very quickly in order to disable prey effectively.  These cells are able to deploy their stinging machinery within 700 nanoseconds.

Currently, researchers are trying to figure out which proteins are involved in this complicated process.  Scientists were able to identify all of the proteins that make up the nematocyst.  They found 410 different proteins that have venomous and structural responsibilities.  We are just beginning to understand the complexities of nematocyst structure in a seemingly simple animal.  

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