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5 December 2013 11:26 am ,
Vol. 342 ,
An animal rights group known as the Nonhuman Rights Project filed lawsuits in three New York courts this week in an...
Researchers have been hot on the trail of the elusive Denisovans, a type of ancient human known only by their DNA and...
Thousands of scientists in the Russian Academy of Sciences (RAS) are about to lose their jobs as a result of the...
Dyslexia, a learning disability that hinders reading, hasn't been associated with deficits in vision, hearing, or...
Exotic, elusive, and dangerous, snakes have fascinated humankind for millennia. They can be hard to find, yet their...
Researchers have sequenced and analyzed the first two snake genomes, which represent two evolutionary extremes. The...
Snake venoms are remarkably complex mixtures that can stun or kill prey within minutes. But more and more researchers...
At age 30, Dutch biologist Freek Vonk has built up a respectable career as a snake scientist. But in his home country,...
- 5 December 2013 11:26 am , Vol. 342 , #6163
- About Us
Building a Better Bug Repellent
17 July 1998 7:00 pm
Chemical warfare is nothing new to insects--or the researchers who study them. But now it turns out that the pupae of the squash beetle can concoct an arsenal of chemical deterrents with a technique human chemists thought they had a monopoly on: combinatorial chemistry, in which hundreds of different compounds can be assembled from the same set of basic chemical building blocks. The finding is reported in today's issue of Science by a group led by Cornell University organic chemist Jerrold Meinwald.
The pupae deploy their hundreds of defensive chemicals in droplets secreted from glandular hairs. The team discovered that the deterrent polyamine compounds were formed from simpler subunits called (w-1)-(2-hydroxyethylamino)alkanoic acids. The pupae seem to have linked the subunits head to tail, in random order and varying proportions, to form scads of molecular rings.
Because the large ring compounds are too heavy to evaporate, they collect in the defensive droplets, where the chemical cacophony continues. By analyzing secretions of different ages, the researchers found that over time, the rings isomerize (flip bonds) to form compounds with the same molecular formulas but different structures. When combined with newer rings pumped out by the pupae, these isomers add to the potent cocktail that deters predators.
"It's really pretty nifty" for evolution to have come up with this way of upping chemical diversity, says Cornell chemical ecologist Thomas Eisner, a co-author. The mix-and-match approach might also have a practical payoff for humans, adds organic chemist Gordon Gribble of Dartmouth College in Hanover, New Hampshire. It could be used against pests someday, Gribble notes, "much like we use DEET to repel mosquitoes."