Spit take
Tasting and spitting out toxic food is a survival trait shared by many complex organisms. Now MIT researchers have shown that a simple roundworm, Caenorhabditis elegans, has the ability to spit out potentially deadly substances — a finding that could have surprising implications for human heart research. To feed, the worm uses its pharynx, a myogenic muscular pump — which contracts without nervous-system stimulation — that rhythmically sucks bacteria into its intestine. In a paper published today in the journal Current Biology, the researchers identify three neural circuits — inside and outside the pharynx — that cause the worm to stop feeding and spit in the presence of light, which generates deadly hydrogen peroxide. Identifying how neurons control the pharynx, the researchers say, could improve understanding of human myogenic muscles — such as the heart and stomach. Like the worm’s pharynx, the human heart, for instance, pumps substances through tubes, and relies...