It won't offer swimmers much help this summer, but scientists are working hard at taking the sting out of jellyfish.

Cnidocytes, with which jellyfish sting, are among the most complicated animal cells. They function as something of a nervous system, and when food or an enemy is detected, they discharge and prey is immobilized either by venom or an adhesive.

Jellyfish stings are much more likely to be fatal to other fish than to humans, but they can cause allergic reactions in some people, and for many the sting of a jellyfish ranks among the worst of summer memories.

"The workings of the stinging cell can be compared to a loaded gun," said Peter Anderson of the University of Florida's Laboratory for Experimental Marine Biology and Medicine. "The stinging capsule is like a bullet ready to be fired. All that is needed is a stimulus for the trigger to be pulled."

The cell's interior is dominated by a coiled thread that in some cases is barbed. When the cell is stimulated physically or chemically, it ejects the barbed thread. While enclosed in the cell, called the cnida, the thread is inside out. When it is expelled, it shoots out like the inverted finger of a glove.

At present, people have two options with jellyfish: avoid stings or treat them.

But Anderson has isolated several types of cnidocytes and is trying to understand the chemical processes that cause their triggers to fire. Using a solution made from extracts of different organisms that jellyfish attack, Anderson will attempt to block the sting.

First he will try to break the chain of chemical receptors on the stinger cell that transfer stimuli. He is also exploring the sequence of intercellular events that link the outside stimulus to a sting, in an attempt to break the chain.

If all else fails, he will work on a way to make jellyfish less sensitive by duplicating their defense methods. Jellyfish do not sting themselves or each other.