Biomarker responses in earthworm coelomocyte extract - Noninvasively collected sample for pesticide effect assessment

Behavioral, histopathological, genetic, and organism-wide responses to phenanthrene-induced oxidative stress in Eisenia fetida earthworms in natural soil microcosms

Phenanthrene (PHE) contamination not only changes the quality of soil environment but also threatens to the soil organisms. There is lack of focus on the eco-toxicity potential of this contaminant in real soil in the current investigation. Here, we assessed the toxic effects of PHE on earthworms (Eisenia fetida) in natural soil matrix. PHE exhibited a relatively high toxicity to E. fetida in natural soil, with the LC₅₀ determined to be 56.68 mg kg^-1 after a 14-day exposure. Excessive ROS induced by PHE, leading to oxidative damage to biomacromolecules in E. fetida, including lipid peroxidation, protein carbonylation, and DNA damage. The antioxidant defense system (total antioxidant capacity, glutathione S-transferase, peroxidase, catalase, carboxylesterase, and superoxide dismutase) in E. fetida responded quickly to scavenge excess ROS and free radicals. Exposure to PHE resulted in earthworm avoidance responses (2.5 mg kg^-1) and habitat function loss (10 mg kg^-1). Histological observations indicated that the intestine, body wall, and seminal vesicle in E. fetida were severely damaged after exposure to high-dose PHE. Moreover, earthworm growth (weight change) and reproduction (cocoon production and the number of juvenile) were also inhibited after exposure to this pollutant. Furthermore, the integrated toxicity of PHE toward E. fetida at different doses and exposure times was assessed by the integrated biomarker response (IBR), which confirmed that PHE is more toxic to earthworms in the high-dose and long-term exposure groups. Our results showed that PHE exposure induced oxidative stress, disturbed antioxidant defense system, and caused oxidative damage in E. fetida. These effects can trigger behavior changes and damage histological structure, finally cause growth inhibition, genotoxicity, and reproductive toxicity in earthworms. The strength of this study is the comprehensive toxicity evaluation of PHE to earthworms and highlights the need to investigate the eco-toxicity potential of exogenous environmental pollutants in a real soil environment.

Earthworm Eisenia andrei modulates oxidative stress in bean plants Vicia faba irrigated with treated wastewater

With respect to reducing the pressure on freshwater resources, treated wastewater (TWW) irrigation represents a sustainable alternative in agriculture. Due to their low quality and variable composition, TWW could entail harmful consequences for living organisms in terrestrial ecosystems. This study aims to evaluate how earthworm (Eisenia andrei) can modulate oxidative stress in bean plants (Vicia faba) that are irrigated over a course of 60 days with two doses of TWW (50 and 100%) in addition to a control condition (0%) irrigated with distilled water. This is achieved by measuring glutathione-S-transferase (GST) activity and malondialdehyde accumulation (MDA) in plants. Furthermore, catalase (CAT), GST, MDA, and acetylcholinesterase (AChE) activities of the earthworms are also assessed. Our results show that growth and physiological parameters are modified when applying TWW irrigation. Moreover, oxidative stress apprehended by GST activity and MDA accumulation is exacerbated in V. faba plants after exposure to increased TWW doses. Similarly, TWW irrigation enhances oxidative stress parameters in earthworms with a crucial decrease in AChE activity. In addition, the presence of earthworms increases growth and physiological parameters; it also results in a significant reduction in GST activity and MDA rate in V. faba plants. Our results provide new insights into the impact of TWW irrigation on soil organisms and the importance of earthworms in the reduction of oxidative stress in plants.