A Promising Indicator of Neurobehavioral Toxicity Using the Nematode Caenorhabditis Elegans and Computer Tracking

Abstract

A promising screening test for neurotoxicity has been developed using a computer tracking system and a species of nematode, Caenorhabditis elegans. The animals are viewed in dark-field illumination by a video camera interfaced directly to a microcomputer. Several hundred nematodes are tracked simultaneously and rates of locomotion and frequency of change of direction are reported in real time. This system can rapidly obtain reliable data on a variety of behavioral parameters relating to locomotion and response to sensory stimulation. Initial testing has examined the effects of six chemicals on locomotion. Four metals (copper, beryllium, mercury, and lead) and two organophosphate pesticides (malathion and vapona) have been studied. Copper and beryllium were chosen as chemicals that have not been shown to be neurotoxins and the other four chemicals were chosen as substances known to be neurotoxins. Our findings indicate that the rate of movement of exposed nematodes compared to the rate of movement of vehicle controls may prove to be useful as an indicator of neurotoxicity.