Slow nutrient turnover and destructed soil function were the main factors causing low efficiency in phytoremediation of heavy metal (HM)-contaminated soil. Soil ecoenzymatic stoichiometry can reflect the ability of soil microorganisms to acquire energy and nutrients, and drive nutrient cycling and carbon (C) decomposition in HM-contaminated soil. Therefore, for the first time, we used the enzymatic stoichiometry modeling to examine the microbial nutrient limitation in rhizospheric and bulk soil of different plants (Medicago sativa, Halogeton arachnoideus and Agropyron cristatum) near the Baiyin Copper Mine. Results showed that the main pollutants in this area were Cu, Zn, Cd, and Pb, while Cd and Zn have the greatest contribution according to the analysis of pollution load index (PLI). The activities of soil C-, nitrogen (N)-, and phosphorus (P)-acquiring enzymes in the rhizosphere of plants were significantly greater than that in bulk soil. Moreover, microbial C and P limitations were observed in all plant treatments, while the lower limitation was generally in the rhizosphere compared to bulk soil. The HM stress significantly increased microbial C limitation and decreased microbial P limitation, especially in the rhizospheric soil. The partial least squares path modeling (PLS-PM) further indicated that HM concentration has the greatest effects on microbial P limitation (−0.64). In addition, the highest enzyme activities and the lowest P limitation were observed in the rhizospheric and bulk soil of M. sativa, thereby implying that soil microbial communities under the remediation of M. sativa were steadier and more efficient in terms of their metabolism. These findings are important for the elucidation of the nutrient cycling and microbial metabolism of rhizosphere under phytoremediation, and provide guidance for the restoration of HM-contaminated soil.

Globally, amphibian species are experiencing dramatic population declines, and many face the risk of imminent extinction. Endocrine-disrupting chemicals (EDCs) have been recognised as an underappreciated factor contributing to global amphibian declines. In this regard, the use of hormonal growth promotants in the livestock industry provides a direct pathway for EDCs to enter the environment—including the potent anabolic steroid 17β-trenbolone. Emerging evidence suggests that 17β-trenbolone can impact traits related to metabolism, somatic growth, and behaviour in non-target species. However, far less is known about possible effects of 17β-trenbolone on anuran species, particularly during early life stages. Accordingly, in the present study we investigated the effects of 28-day exposure to 17β-trenbolone (mean measured concentrations: 10 and 66 ng/L) on body size, body condition, metabolic rate, and anxiety-related behaviour of tadpoles (Limnodynastes tasmaniensis). Specifically, we measured rates of O₂ consumption of individual tadpoles as a proxy for metabolic rate and quantified their swimming activity and their time spent in the upper half of the water column as indicators of anxiety-related behaviour. Counter to our predictions based on effects observed in other taxa, we detected no effect of 17β-trenbolone on body size, metabolic rate, or behaviour of tadpoles; although, we did detect a subtle, but statistically significant decrease in body condition at the highest 17β-trenbolone concentration. We hypothesise that 17β-trenbolone may induce taxa-specific effects on metabolic function, growth, and anxiety-related behaviour, with anurans being less sensitive to disruption than fish, and encourage further cross-taxa investigation to test this hypothesis.

Phenanthrene (PHE) is widely distributed, and it can cause genotoxicity in humans by interacting with enzymes in the body. A current challenge for PHE bioremediation is the inhibitory effect of biotoxic intermediates on bacterial growth. Notably, the aerobic biotransformation processes for PHE in the presence of sophorolipids have been poorly studied. Here, a PHE-degrading strain was isolated from sediments and identified as Pseudomonas stutzeri and named LSH-PAH1. It was observed that 1-naphthol (a biotoxic substance that can inhibit strain growth) was produced during the PHE metabolism process of LSH-PAH1. The biodegradation ratio increased from 21.4% to 91.7% within 48 h after the addition of sophorolipids. Unexpectedly, this addition accelerated the metabolic process for 1-naphthol rather than causing its accumulation. The cometabolism of 1-naphthol and sophorolipids alleviated the biotoxic effects for the strain, which was verified by gene expression analysis. We identified a new PHE-degrading strain and provided a mechanism for PHE biodegradation using LSH-PAH1 with the addition of sophorolipids, which provides a reference for practical applications of the bioremediation of PHE and study of the cometabolism of biotoxic intermediates.

Arsenic (As) and cadmium (Cd), two major carcinogenic heavy metals, enters into human food chain by the consumption of rice or rice-based food products. Both As and Cd disturb plant-nutrient homeostasis and hence, reduces plant growth and crop productivity. In the present study, As/Cd modulated responses were studied in non-basmati (IR-64) and basmati (PB-1) rice varieties, at physiological, biochemical and transcriptional levels. At the seedling stage, PB-1 was found more sensitive than IR-64, in terms of root biomass; however, their shoot phenotype was comparable under As and Cd stress conditions. The ionomic data revealed significant nutrient deficiencies in As/Cd treated-roots. The principal component analysis identified NH₄⁺ as As-associated key macronutrient; while, NH₄⁺/NO₃⁻ and K⁺ was majorly associated with Cd mediated response, in both IR-64 and PB-1. Using a panel of 21 transporter gene expression, the extent of nutritional deficiency was ranked in the order of PB-1(As)<IR-64(As)<PB-1(Cd)<IR-64(Cd). A feed-forward model is proposed to explain nutrient deficiency induced de-regulation of gene expression, as observed under Cd-treated IR-64 plants, which was also validated at the level of sulphur metabolism related enzymes. Using urea supplementation, as nitrogen-fertilizer, significant mitigation was observed under As stress, as indicated by 1.018- and 0.794-fold increase in shoot biomass in IR-64 and PB-1, respectively compared to that of control. However, no significant amelioration was observed in response to supplementation of urea under Cd or potassium under As/Cd stress conditions. Thus, the study pinpointed the relative significance of various macronutrients in regulating As- and Cd-tolerance and will help in designing suitable strategies for mitigating As and/or Cd stress conditions.

Artificial light at night (ALAN) alters circadian rhythms in animals and therefore can be a source of environmental stress affecting their physiology and behaviour. The impact of ALAN can be related to the increased light level, but also to the spectral composition of night lighting. Previous research showed that many species can be particularly sensitive to the LED light, but it is unclear if they respond to its broad spectrum or specifically to the blue light wavelength. In this study, we tested whether dim ALAN (2 lx) differing in the spectral quality (warm white LED, blue LED, high-pressure sodium HPS light) modifies behaviour and changes oxidative status in two nocturnal freshwater shredder species: Dikerogammarus villosus and Gammarus jazdzewskii (Gammaroidea, Amphipoda). Our experiment revealed that ALAN, irrespective of its spectral quality, did not affect the oxidative stress markers in cells (the level of reactive oxygen species and lipid peroxidation). However, ALAN changed the gammarid behaviour in a species-specific manner, which can potentially reduce the fitness of the shredders. Dikerogammarus villosus avoided all types of light compared to darkness. Therefore, confined to the shelter, D. villosus may have fewer opportunities to forage and/or mate. Gammarus jazdzewskii was sensitive only to the narrow-spectrum blue light, but did not respond to the HPS and white LED light. Avoidance is a typical response of gammarids to natural light, thus the disruption of this behaviour in the presence of common ALAN sources can increase the predation risk in this species. To summarize, behavioural modifications induced by ALAN seem more pronounced than changes in physiology and can constitute the main driver of disturbances in the processing of organic matter in freshwater ecosystems by invertebrate shredders.

This study investigated the control of dissolved organic matter (DOM) molecular compositions by microbial community shifts under temperature regulation (range from 5 to 35 °C), using riverine DOM and in situ microorganisms as examples. The functioning of different microbial metabolisms, including the utilization and generation processes, was comprehensively analyzed. Though the overall quantity of DOM was less temperature-affected, more molecules were identified at moderate temperatures (e.g., 15 and 25 °C) and their accumulated mass peak intensities increased with the temperature. The results were ascribed to 1) the microbial production of macromolecular (m/z > 600) CHO, CHON, and CHONS species was stimulated at higher temperatures; 2) the microorganisms consumed more DOM molecules at both higher and lower temperatures; and 3) the simultaneously decreased utilization and increased generation of recalcitrant CHO and CHON molecules with m/z < 600 at higher temperatures. The strong correlations among the temperature, community structures, and DOM chemodiversity suggested that temperature promoted the community evenness to increase the DOM generation. In addition, the higher temperature decreased the abundance of microorganisms that utilized more recalcitrant molecules and produced fewer new molecules (e.g., Proteobacteria, Acinetobacter, and Erythrobacter) while increased others that functioned the opposite (e.g., Verrucomicrobia, Bacteroidetes, and Flavobacterium) to increase the DOM production. The constructed temperature-community-DOM chemistry relationship deepened the molecular-level understanding of DOM variations and provided implications for the warming future.

To understand how climate change stressors might affect marine organisms and support adequate projections it is important to know how multiple stressors may be modulated by the presence of other species. We evaluated the direct effects of ocean warming (OW) and ocean acidification (OA) together with non-consumptive effects (NCEs) of the predatory crab Acanthocyclus hassleri on early ontogeny fitness-related traits of the commercially important rocky-shore keystone gastropod Concholepas concholepas. We measured the response of nine traits to these stressors at either the organismal level (survival, growth, feeding rates, tenacity, metabolic rate, calcification rate) or sub-organismal level (nutritional status, ATP-supplying capacity, stress condition). C. concholepas survival was not affected by any of the stressors. Feeding rates were not affected by OW or OA; however, they were reduced in the presence of crab NCEs compared with control conditions. Horizontal tenacity was affected by the OA × NCEs interaction; in the presence of NCEs, OA reduced tenacity. The routine metabolic rate, measured by oxygen consumption, increased significantly with OW. Nutritional status assessment determined that carbohydrate content was not affected by any of the stressors. However, protein content was affected by the OA × NCEs interaction; in the absence of NCEs, OA reduced protein levels. ATP-supplying capacity, measured by citrate synthase (CS) activity, and cellular stress condition (HSP70 expression) were reduced by OA, with reduction in CS activity found particularly at the high temperature. Our results indicate C. concholepas traits are affected by OA and OW and the effects are modulated by predator risk (NCEs). We conclude that some C. concholepas traits are resilient to climate stressors (survival, growth, horizontal tenacity and nutritional status) but others are affected by OW (metabolic rate), OA (ATP-supplying capacity, stress condition), and NCEs (feeding rate). The results suggest that these negative effects can adversely affect the associated community.

Perfluorooctanesulfonic acid (PFOS) is a persistent anthropogenic chemical that can affect the thyroid hormone system in humans and animals. In adults, thyroid hormones (THs) are regulated by the hypothalamic-pituitary-thyroid (HPT) axis, but also by organs such as the liver and potentially the gut microbiota. PFOS and other xenobiotics can therefore disrupt the TH system at various locations and through different mechanisms. To start addressing this, we exposed adult male rats to 3 mg PFOS/kg/day for 7 days and analysed effects on multiple organs and pathways simultaneously by transcriptomics. This included four primary organs involved in TH regulation, namely hypothalamus, pituitary, thyroid, and liver. To investigate a potential role of the gut microbiota in thyroid hormone regulation, two additional groups of animals were dosed with the antibiotic vancomycin (8 mg/kg/day), either with or without PFOS. PFOS exposure decreased thyroxine (T4) and triiodothyronine (T3) without affecting thyroid stimulating hormone (TSH), resembling a state of hypothyroxinemia. PFOS exposure resulted in 50 differentially expressed genes (DEGs) in the hypothalamus, 68 DEGs in the pituitary, 71 DEGs in the thyroid, and 181 DEGs in the liver. A concomitant compromised gut microbiota did not significantly change effects of PFOS exposure. Organ-specific DEGs did not align with TH regulating genes; however, genes associated with vesicle transport and neuronal signaling were affected in the hypothalamus, and phase I and phase II metabolism in the liver. This suggests that a decrease in systemic TH levels may activate the expression of factors altering trafficking, metabolism and excretion of TH. At the transcriptional level, little evidence suggests that the pituitary or thyroid gland is involved in PFOS-induced TH system disruption.

The recently recognized adverse environmental and toxic effects of neonicotinoid insecticides (NNIs) on non-target organisms are alarming. A comprehensive design, screening, and regulatory system was developed to generate NNI derivatives and mutant receptors with selective-ecotoxicological effects to overcome such adverse effects. For ligand design, taking ACE-09 derivative as an example, the toxicity on non-target animals (aboveground: bees; underground: earthworms), plant absorption, and soil absorption decreased by 4.80% and 13.7%, 10.0%, and 121%, while the toxicity on target animals (aboveground: aphids; underground: B. odoriphagas), plant metabolism, and soil degradation increased by 70.2% and 51.7%, 5.08%, and 8.28%. For receptor modification, the ability of mutants to absorb ACE-09 derivative decreased by 31.0%, while the ability of mutants to metabolize ACE-09 derivative increased by 28.0% in scenario 2 (mainly plant selectivity); the ability of mutants to degrade ACE-09 derivative increased by 11.6% in scenario 3 (mainly soil selectivity). The above results indicated that the selective-ecotoxicological effects of ligand design and receptor modification were both improved. Additionally, the combined effects of the ACE-09 derivative on plant absorption and metabolic mutants improved by 31.1% and 31.4% in scenario 2, respectively, while the effect on microbial degradation mutant improved by 14.9%, indicating that there was a synergistic effect between ligand design and receptor modification. Finally, based on the interaction between the ACE-09 derivative and mutants, the optimal environmental factors that improved the selectivity of their ecotoxicological effects were determined. For example, alternate application of nitrogen and phosphorus fertilizers effectively reduced the oxidative damage to plants caused by NNI residues. The novel ligand-receptor joint modification method, combined with the regulation of environmental factors under multiple scenarios, can biochemically address the ecotoxicological concern and highlight the harmful effects of pesticides on the environment and non-target organisms.