Using nuclear magnetic resonance (NMR) spectroscopy, King and his colleagues have determined the three-dimensional structures of specific neurotoxins from the funnel-web spider -- toxins that either paralyze insects or send their nervous systems into overdrive. King's NSF-funded research has provided the first detailed descriptions of the regions of the toxins that are essential for interaction with insect ion channels. (Ion channels allow the movement of ions -- small charged molecules -- across cell membranes.)
His next challenge is to use this information to design insecticides that specifically target insect pests without affecting vertebrates. One approach is to create chemical insecticides that mimic the action of spider toxins. Many insects have developed immunity to DDT and other chemical controls because most insecticides are neurotoxins that act against only a small number of nervous system targets. King's spider-venom cocktails could be designed to thwart the resistance of specific insect pests by locking on to novel molecular targets in the insect nervous system. Because the insects have never encountered chemicals that behave like spider toxins, they will most likely lack resistance to bioinsecticides derived from funnel-web venom.
Another strategy is to insert a gene for encoding a spider toxin into viruses that are specific to a particular insect genus, or even a small number of species within a genus. The toxin-enhanced virus would act like a magic insecticide bullet, targeting only cotton bollworms, for example, and leaving bees and other beneficial insects unharmed. Unlike some conventional insecticides, the toxins used in the engineered virus would not end up in the food supply.
Recent laboratory research on cockroaches and tobacco budworms demonstrates that the toxin
Source:National Science Foundation