C. elegans, a nematode (roundworm) that lives in soil, feeds on bacteria that grow on decaying organic matter. But one genus of bacteria, Streptomyces, fights back against these nematode predators with chemical toxins known as nematicides. Indeed avermectin, a nematicide produced by Streptomyces avermitilis discovered in 1978, is such a valuable drug in the treatment of parasitic worms in humans, that its discoverers were awarded a Nobel Prize in Physiology or Medicine in 2015.
Now a new study, published in the journal eLife, reveals how nematodes escape when they enter into nematicide-containing soil: they sense dodecanoic acid, a tell-tale sign that the Streptomyces bacteria are nearby. The study, involving a multidisciplinary collaboration between SJSU and UCSF, has found that C. elegans detects the Streptomyces-produced dodecanoic acid trail via a specific chemosensory receptor expressed in sensory neurons in the head and tail, and hastens a retreat from the area before succumbing to the nematocides.
The scientific team making this discovery was an exemplar of multidisciplinary research including students and faculty researchers from six departments at two universities. The team was led by Profs. Miri VanHoven (Biological Sciences) and Laura Miller Conrad (Chemistry) and included Profs. Daryl Eggers (Chemistry), Martina Bremer (Mathematics and Statistics), and Sami Khuri (Computer Science) all from SJSU and Prof. Noelle L’Etoile (Cell and Tissue Biology) and Dr. Colleen O’Loughlin (Bioengineering and Therapeutic Sciences) from UCSF.