Insects, be warned. Research on three continents has turned up two new classes of selective pesticides that immobilize and eventually kill many insect species by interfering with a cell receptor unique to the insects. The novel chemicals could potentially prevent infestations of crops while posing minimal danger to noninsects.
"Both classes of chemicals act at the ryanodine receptor," making them the first synthetic molecules to demonstrate this insect-imperiling behavior, says physiologist Daniel Cordova of DuPont Crop Protection in Newark, Del. By regulating how calcium moves within animal cells, that receptor plays an essential role in processes such as muscle contraction.
Ryanodine binds to its receptor, says Cordova, "acting much like a doorstop, in that it locks the channel in a partially open state, resulting in calcium depletion" within cells and loss of muscle control. Vertebrates have two or three forms of the receptor, none of which is identical to the single