Toxicity in relation to mode of action for the nematode Caenorhabditis elegans: Acute-to-chronic ratios and quantitative structure–activity relationships

Abstract

Acute-to-chronic ratios (ACRs) and quantitative structure-activity relationships (QSARs) are of particular interest in chemical risk assessment. Previous studies focusing on the relationship between the size or variation of ACRs to substance classes and QSAR models were often based on data for standard test organisms, such as daphnids and fish. In the present study, acute and chronic toxicity tests were performed with the nematode Caenorhabditis elegans for a total of 11 chemicals covering 3 substance classes (nonpolar narcotics: 1-propanol, ethanol, methanol, 2-butoxyethanol; metals: copper, cadmium, zinc; and carbamates: methomyl, oxamyl, aldicarb, dioxacarb). The ACRs were variable, especially for the carbamates and metals, although there was a trend toward small and less variable ACRs for nonpolar narcotic substances. The octanol-water partition coefficient was a good predictor for explaining acute and chronic toxicity of nonpolar narcotic substances to C. elegans, but not for carbamates. Metal toxicity could be related to the covalent index χm2r. Overall, the results support earlier results from ACR and QSAR studies with standard freshwater test animals. As such C. elegans as a representative of small soil/sediment invertebrates would probably be protected by risk assessment strategies already in use. To increase the predictive power of ACRs and QSARs, further research should be expanded to other species and compounds and should also consider the target sites and toxicokinetics of chemicals.

Passive Dosing in Chronic Toxicity Tests with the Nematode Caenorhabditis elegans

“…Similar to studies with daphnids, algae, and C. elegans, , our results showed that, when applied by passive dosing, BaA and ANT exhibit chronic toxicity to C. elegans at chemical activities <0.01, demonstrating the need to use acute to chronic ratios with respect to baseline toxicity at a specific chemical activity.…”

Data-Driven Learning of Narcosis Mode of Action Identifies a Cns Transcriptional Signature Shared between Whole Organism Caenorhabditis Elegans and a Fish Gill Cell Line

“…S1). EC 50 values were calculated using the drc package in R. When compared to previous EC 50 test results for C. elegans (Li et al, 2013;Ristau et al, 2015), we find a unusually high amount of deviation from the regression line (Fig. S2).…”

Ecotoxicological characterization of micropollutants and wastewater samples from conventional biological and advanced wastewater treatment

“…C. elegans has also been involved in microcosm studies and community analyses (e.g., Hägerbäumer et al 2015, Mueller et al 2020a, Wilson and Khakouli-Duarte 2009. The nematode thereby proved to be a versatile tool for answering toxicokinetic (Burns et al 2010, Kim et al 2019a, Liu et al 2019, Mueller et al 2020b, Offermann et al 2009, Ristau et al 2015, Roh et al 2014, Stylianou et al 2018 and toxicodynamic research questions (compare below).…”