Adverse Effects of Unsaturated Organic Compounds on Kinetic States During Locomotion Uncovered by Comprehensive Analysis of Behavioral Toxicities in C. elegans.

Organisms in human living spaces are surrounded by a variety of engineered substances. These chemical compounds have unexpected effects on the environment and human health. In particular, workers in industries face the risk of a health hazard caused by high-dose or long-term exposure to chemicals in the workplace. Thus, understanding chemical toxicities in a multifaceted manner is necessary to save the environment and human health from engineered chemicals. In this study, the behavioral toxicities of workplace chemicals with various functional groups are assessed using Caenorhabditis elegans. I compared the acute effects of 68 chemical compounds on locomotion speed with a lethal dose of 50% (LD50) in mammals, and a significant correlation was found between them. Allyl alcohol is toxic to the internal organs, such as the liver and stomach, dependent on acrolein, an α,β-unsaturated aldehyde metabolized by alcohol dehydrogenase in mammals. Allyl alcohol caused various abnormalities in C. elegans locomotion dependent on ADH-1, an ortholog of alcohol dehydrogenase, indicating the adverse effects of acrolein on behavior. Further locomotion tests revealed that chemicals with unsaturated carbon adjacent to electron-withdrawing functional groups, such as carbonyl, nitrile, and sulfonyl groups, caused a common effect on locomotion, which is a substantial increase in the frequency of backward movement during random locomotion. Accordingly, this study proposes the usefulness of locomotion tests in C. elegans for estimating the acute toxicities of chemicals across species and understanding the common features of chemical groups that cause adverse effects on behavior.