Analysis of earthworm sublethal toxic responses to atrazine exposure using ¹H nuclear magnetic resonance (NMR)‐based metabolomics

Abstract

Atrazine toxicity to earthworms is still not fully understood, particularly at sublethal concentrations. Because of the ubiquity of atrazine in the environment, it is imperative to understand the impacts of atrazine presence to soil-dwelling organisms. To examine this in detail, we used H nuclear magnetic resonance (NMR)-based metabolomics to elucidate earthworm (Eisenia fetida) responses after 48 h of atrazine exposure in contact tests. Earthworms were exposed to 4 sublethal concentrations of 362.4, 181.2, 90.6, and 45.3 ng/cm , which correspond to 1/8th, 1/16th, 1/32nd, and 1/64th of the median lethal concentration (LC50) values, respectively. After exposure, polar metabolites were isolated from earthworm tissues and analyzed using H NMR spectroscopy. Sublethal atrazine exposure induced a nonmonotonic response with respect to exposure concentration and caused an overall suppression in earthworm metabolism. Maltose, fumarate, malate, threonine/lactate, adenosine-5'-triphosphate (ATP), betaine, scyllo-inositol, glutamate, arginine, and glutamine were the metabolites identified as most sensitive to atrazine exposure. These observed fluctuations in the metabolic profile suggest that atrazine reduced ATP synthesis and negatively impacted the health of earthworms after acute sublethal exposure. Our study also demonstrates the utility of NMR-based metabolomics for the basic assessment of sublethal toxicity, which can then be used for more targeted approaches with other molecular techniques. Environ Toxicol Chem 2018;37:473-480. © 2017 SETAC.

High-throughput transcriptomics reveals the mechanisms of nanopesticides – nanoformulation, commercial formulation, active ingredient – finding safe and sustainable-by-design (SSbD) options for the environment

“…glucose storage – gluconeogenesis). Similar results were reported for other invertebrates such as the fruit fly Drosophila melanogaster , 50 while in Enchytraeus albidus (enchytraeid) 51 and Eisenia fetida (earthworm), 52 gluconeogenesis was enhanced in response to atrazine exposure, although at a shorter exposure period – 2 days. The differences between the two enchytraeid species ( E. crypticus and E. albidus ) could be related to the different sensitivities reported towards ATZ exposure.…”

Metabolomic Analysis of Hexagenid Mayflies Exposed to Sublethal Concentrations of Naphthenic Acid

“…However, shifts in the lipid metabolome observed at our highest naphthenic acid exposure level indicate that a biochemical response may be initiated at levels approximating our highest treatment level (100 μg L −1 ) suggesting a potential threshold for naphthenic acid effects. Such threshold responses have been observed in other studies assessing non-lethal levels of contaminants using metabolomics (e.g., (Lankadurai et al, 2011a;Lankadurai et al, 2011b;Dani et al, 2018). However, because we limited our study to concentrations currently observed in aquatic environments and the evidence for a potential threshold occurs at the highest concentration tested in our study we cannot confirm this form of response from our results.…”