Caenorhabditis elegans: lectin-mediated modification of chemotaxis.

Binding of the lectins concanavalin A (Con A) and limulin to Caenorhabditis elegans wild type resulted in consistent, reproducible, partial inhibition of chemoattraction to sterile filtrates of Escherichia coli. Normal chemotaxis resumed within 8 hr following treatment with these lectins. Competitive displacement of Con A or limulin by flooding with the specific sugars resulted in rapid resumption of normal chemotactic behavior. The experimental protocol for Con A applied to three age groups (newly hatched larvae, young adults, and old adults) showed the same response for all groups tested. Two mutant C. elegans with morphological defects in the cephalic chemosensilla showed the same inhibition of chemotactic response after exposure to Con A, and rapidly resumed normal behavior after competitive displacement of the lectin. Limulin and Con A did not affect nematode growth, development, or longevity, demonstrating that the observed results were not attributable to toxic effects. These results and other experimental evidence support the premise that behavioral modification was caused by functional impairments caused by Con A and limulin to chemoreceptors located on sensory dendrites of the cephalic sensilla.