60-Second Science

Roach Reactions to Venom Point to Targeted Pesticides

Small changes in the protein sequence of sodium channels of American compared with German cockroaches leave the latter susceptible to a venom that has little effect on the former. Cynthia Graber reports 


An honest error has led to promising research into the development of species-specific insecticides. The account is in the journal Nature Communications. [Niraj S. Bende et al, A distinct sodium channel voltage-sensor locus determines insect selectivity of the spider toxin ​Dc1a]

A team of Johns Hopkins scientists study sodium channels responsible for electrical signaling in nerve cells from humans and from cockroaches. Spider venom protein messes with these sodium channels—that’s why venom is dangerous. So the researchers use spider venom protein to disrupt the channels and thus clarify exactly how the channels function. 

The researchers recently asked for venom protein samples from Australian collaborators. And the Aussies accidentally included a spider venom protein that has no effect on humans or American cockroaches.  

In their tests, the Hopkins researchers found when sodium channels from German cockroaches were exposed to the mistakenly included sample, their activity skyrocketed, enough to cause death-inducing seizures.

Intrigued that the American roach sodium channel laughed off the venom that would kill the German roach, the scientists found a key region on the two species’ channels that differed by only two amino acids. The scientists say the information could help with the creation of insecticides that target one harmful insect species without hurting beneficial ones, like bees. As the study authors note: “The more specific a toxin's target, the less dangerous it is for everything else."

—Cynthia Graber

[The above text is a transcript of this podcast.]

Scientific American is part of the Nature Publishing Group

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