Gut pathobiome mediates behavioral and developmental disorders in biotoxin-exposed amphibians.

Emerging evidence suggests a link between alterations in the gut microbiome and adverse health outcomes in the hosts exposed to environmental pollutants. Yet, the causal relationships and underlying mechanisms remain largely undefined. Here we show that exposure to biotoxins can affect gut pathobiome assembly in amphibians, which in turn triggers the toxicity of exogenous pollutants. We used Xenopus laevis as a model in this study. Tadpoles exposed to tropolone demonstrated notable developmental impairments and increased locomotor activity, with a reduction in total length by 4.37%-22.48% and an increase in swimming speed by 49.96%-84.83%. Fusobacterium and Cetobacterium are predominant taxa in the gut pathobiome of tropolone-exposed tadpoles. The tropolone-induced developmental and behavioral disorders in the host were mediated by assembly of the gut pathobiome, leading to transcriptome reprogramming. This study not only advances our understanding of the intricate interactions between environmental pollutants, the gut pathobiome, and host health but also emphasizes the potential of the gut pathobiome in mediating the toxicological effects of environmental contaminants.

Multiomics Sequencing and AlphaFold2 Analysis of the Stereoselective Behavior of Mefentrifluconazole for Bioactivity Improvement and Risk Reduction.

As the first isopropanol chiral triazole fungicide, mefentrifluconazole has broad prospects for application. In this study, the stereoselective stability, bioactivity, fate, and biotoxicity were systematically investigated. Our results indicated that the stability of mefentrifluconazole enantiomers differed between environmental media, and they were stable in water and sediment in the dark. The bactericidal activity of R-mefentrifluconazole against the four target pathogens was 4.6-43 times higher than that of S-mefentrifluconazole. In the water-sediment system, S-mefentrifluconazole dissipated faster than R-mefentrifluconazole in water; however, its accumulation capacity was higher than that of R-mefentrifluconazole in sediment and zebrafish. S-Mefentrifluconazole induced more differentially expressed genes (DEGs) and differentially expressed proteins (DEPs) in zebrafish than did R-mefentrifluconazole. Multiomics sequencing results showed that S-mefentrifluconazole enhanced the antioxidant, detoxification, immune, and metabolic functions of zebrafish by interacting with related proteins. Based on AlphaFold2 modeling and molecular docking, mefentrifluconazole enantiomers had different binding modes with key target proteins in pathogens and zebrafish, which may be the main reason for the stereoselective differences in bioactivity and biotoxicity. Based on its excellent bioactivity and low biotoxicity, the R-enantiomer can be developed to improve the bioactivity and reduce the risk of mefentrifluconazole.

Core bacteria carrying the genes associated with the degradation of atrazine in different soils.

Atrazine residues can pose serious threats to soil ecology and human health. Currently, the underlying relationship between soil microbial communities and the degradation genes associated with atrazine degradation remains unclear. In this study, the degradation characteristics of atrazine was investigated in ten different soil types. Further, diversity and abundance of degradation genes and succession of the bacterial community were also studied. The degradation of 10 mg/kg atrazine in different soil types exhibited an initial rapid trend followed by a gradual slowdown, adhering to the first-order kinetic equation. Atrazine significantly increased the absolute abundance of atz degradation genes. The increase in the absolute abundance of atzC gene was the largest, whereas that of atzA gene was the smallest, and the trzD gene was only detected in the Binzhou loam soil. Co-occurrence network analysis showed that the number of potential bacterial hosts of atzC was the highest compared with the other atz genes. Atrazine also altered the structural composition of the soil microbial community. The relative abundances of Ochrobactrum, Nocardiopsis, Lactobacillus, and Brevibacterium was increased in the atrazine-treated soils, while those of Conexibate, Solirubacter, and Micromonospora was decreased significantly compared with the control. Additionally, four atrazine-degrading bacterial strains Rhizobium AT1, Stenotrophomonas AT2, Brevibacterium AT3, and Bacillus AT4 were isolated from the atrazine-treated soils. After 14 d for inoculation, their degradation rate for 10 mg/L atrazine ranged from 17.56 % to 30.55 %. Moreover, the relative abundances of the bacterial genera, including these four isolates, in the atrazine-treated soil were significantly higher than those in the control, indicating that they were involved in the synergistic degradation of atrazine in the soil. This study revealed the degradation characteristics of atrazine, distribution of degradation genes, and succession of microbial communities, and explored the internal relationship between microbial community structure and atrazine degradation mechanisms in different soil types.

A systematic analysis of residue and risk of cyantraniliprole in the water-sediment system: Does metabolism reduce its environmental risk?

As a representative variety of diamide insecticides, cyantraniliprole has broad application prospects. In this study, the fate and risk of cyantraniliprole and its main metabolite J9Z38 in a water-sediment system were investigated. The present result showed that more J9Z38 was adsorbed in the sediment at the end of exposure. However, the bioaccumulation capacity of cyantraniliprole in zebrafish was higher than that of J9Z38. Cyantraniliprole had stronger influence on the antioxidant system and detoxification system of zebrafish than J9Z38. Moreover, cyantraniliprole induced more significant oxidative stress effect and more differentially expressed genes (DEGs) in zebrafish. Cyantraniliprole had significantly influence on the expression of RyR-receptor-related genes, which was confirmed by resolving their binding modes with key receptor proteins using AlphaFold2 and molecular docking techniques. In the sediment, both cyantraniliprole and J9Z38 had inhibitory effects on microbial community structure diversity and metabolic function, especially cyantraniliprole. The methane metabolism pathway, mediated by methanogens such as Methanolinea, Methanoregula, and Methanosaeta, may be the main pathway of degradation of cyantraniliprole and J9Z38 in sediments. The present results demonstrated that metabolism can reduce the environmental risk of cyantraniliprole in water-sediment system to a certain extent.

Earthworms synergize with indigenous soil functional microorganisms to accelerate the preferential degradation of the highly toxic S-enantiomer of the fungicide imazalil in soil.

The roles of soil and earthworm gut microorganisms in the degradation of the chiral fungicide imazalil (IMA) enantiomers were systemically studied in soil-earthworm systems. S-IMA degraded slower than R-IMA in soil without earthworms. After the addition of earthworms, S-IMA degraded faster than R-IMA. Methylibium was the potential degradative bacterium likely related to the preferential degradation of R-IMA in soil. However, the addition of earthworms significantly decreased the relative abundance of Methylibium, especially in R-IMA-treated soil. Meanwhile, a new potential degradative bacterium Aeromonas first appeared in soil-earthworm systems. Compared with enantiomer-treated soil, the relative abundance of indigenous soil bacterium Kaistobacter significantly boomed in enantiomer-treated soil with earthworms. Interestingly, Kaistobacter in the earthworm gut also obviously increased after exposure to enantiomers, particularly in S-IMA-treated soil, which was associated with the significant increase in Kaistobacter in soil. More importantly, the relative abundances of Aeromonas and Kaistobacter in S-IMA-treated soil were obviously higher than those in R-IMA-treated soil after the addition of earthworms. Moreover, these two potential degradative bacteria were also potential bacterial hosts of the biodegradation genes p450 and bph. Collectively, gut microorganisms are important helpers in soil pollution remediation by participating in the preferential degradation of S-IMA mediated by indigenous soil microorganisms.

The fate, acute, and subchronic risks of dinotefuran in the water-sediment system: A systematic analysis at the enantiomer level.

Environmental risks associated with neonicotinoid insecticides have attracted considerable attention. This study systematically investigated the stereoselective behavior of dinotefuran in a water-sediment system. The results showed that S-dinotefuran accumulated more easily in sediment and zebrafish. Although dinotefuran enantiomers and metabolites present a low risk to aquatic organisms, the risk of dinotefuran enantiomers to sediment organisms should be considered. Additionally, S-dinotefuran induced more remarkable oxidative damage in zebrafish than that of R-dinotefuran. Nevertheless, R-dinotefuran remarkably activated antioxidant and detoxifying enzymes. Multi-omics analyses revealed that S-dinotefuran induced more differentially expressed genes (DEGs) and differentially expressed proteins (DEPs) in zebrafish. In particular, S-dinotefuran inhibited the expression of ribosome- and proteasome-related genes and proteins, affecting the synthesis and degradation of proteins in zebrafish. R-dinotefuran remarkably activated peroxisome-related genes and proteins, thereby enhancing antioxidant and detoxification abilities of zebrafish. The stereoselective interactions between dinotefuran enantiomers and key DEPs were elucidated using AlphaFold2 modeling and molecular docking techniques, which may serve as the main reason for stereoselective subchronic toxicity. The present study is beneficial for the correct use of dinotefuran and provides an effective means for elucidating the mechanism of the stereoselective behavior of chiral compounds.

Systematic evaluation of chiral fungicide penflufen for the bioactivity improvement and input reduction using alphafold2 models and transcriptome sequencing.

Traditional risk assessment of pesticide concludes at the racemic level, which is often incomprehensive. In this study, systematic studies on environmental stability, bioactivity, and ecotoxicological effects of fungicide penflufen were carried out at the enantiomeric level. The single-enantiomer of penflufen was successfully separated and prepared, and their stability was verified in different environmental matrices. Meanwhile, bioactivity test indicated that S-(+)-penflufen had increased bioactivity with its bioactivities against Rhizoctonia solani, Fusarium oxysporum, and Fusarium moniliforme being factors of 7.8, 1.8, and 4.7, respectively greater than those of R-(-)-penflufen. Molecular docking results showed the strong hydrogen bond interactions with Leu300, enantiomer-specific hydrophobic interactions with Cys299, Arg91, and His93, and the greater binding energy between S-(+)-penflufen and succinate dehydrogenase of Rhizoctonia solani caused the selective bioactivity. Additionally, two enantiomers showed low acute toxicity whereas selective sub-chronic toxicity to earthworms. In sub-chronic toxicity test, the accumulated enantiomers caused abnormalities in intestinal tract structure, enzyme activities, and gene expression of earthworms, especially in the S-(+)-penflufen treatment. The selective interactions between penflufen enantiomers and key proteins were elucidated using molecular docking, which may be the main reason of stereoselective subchronic toxicity. S-(+)-penflufen has high bioactivity and low acute risk, it has great potential for development.

Indigenous functional microbial degradation of the chiral fungicide mandipropamid in repeatedly treated soils: Preferential changes in the R-enantiomer.

This study investigated the indigenous functional microbial communities associated with the degradation of chiral fungicide mandipropamid enantiomers in soils repeatedly treated with a single enantiomer. The R-enantiomer degraded faster than the S-enantiomer, with degradation half-lives ranging from 10.2 d to 79.2 d for the R-enantiomer and 10.4 d to 130.5 d for the S-enantiomer. Six bacterial genera, (Burkholderia, Paraburkholderia, Hyphomicrobium, Methylobacterium, Caballeronia, and Ralstonia) with R-enantiomer substrate preference and three bacterial genera (Haliangium, Sorangium, and Sandaracinus) with S-enantiomer substate preference were responsible for the preferential degradation of the R-enantiomer and S-enantiomer, respectively. KEGG analysis indicated that Burkholderia, Paraburkholderia, Hyphomicrobium, and Methylobacterium were the dominant contributors to soil microbial metabolic functions. Notably, six microbial metabolic pathways and twelve functional enzyme genes were associated with the preferential degradation of the R-enantiomer, whose relative abundances in the R-enantiomer treatment were higher than those in the S-enantiomer treatment. A constructed biodegradation gene (BDG) protein database analysis further confirmed that Burkholderia, Paraburkholderia, Hyphomicrobium, Methylobacterium, and Ralstonia were the potential hosts of five dominant BDGs, bphA1, benA, bph, p450, and ppah. We concluded that bacterial genera Burkholderia, Paraburkholderia, Hyphomicrobium, and Methylobacterium may play pivotal roles in the preferential degradation of mandipropamid R-enantiomer in repeatedly treated soils.

Assessing the bioavailability and biotoxicity of spiromesifen and its main metabolite spiromesifen-enol (M01) reveals the defense mechanisms of earthworms (Eisenia fetida).

As a promising acaricide and potentially hazardous material, the defense mechanisms of non-target organisms to its exposure are unknown. This study investigates the bioavailability and biotoxicity of spiromesifen and spiromesifen-enol (M01), its main metabolite, in Eisenia fetida. The results showed that M01 was more persistent in the soil environment and E. fetida than spiromesifen. Transcriptome analysis indicated that the spiromesifen- and M01-induced differentially expressed genes (DEGs) were mainly enriched in lysosomal and phagosomal pathways. Analysis of the key common DEGs showed that both spiromesifen and M01 significantly influenced the lysosomes, phagosomes, antioxidant systems, and detoxification systems. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) showed that spiromesifen and M01 damaged E. fetida epidermis and enhanced lysosomal and phagosomal activities. Significant oxidative stress effects were observed at the end of exposure. The hydroxyl free radical (·OH-) content and neutral red retention time (NRRT) could serve as sensitive early biomarkers to predict their pollution. These results revealed the synergistic effects of the epidermis, lysosomes, phagosomes, antioxidant systems, and detoxification system in resisting spiromesifen- and M01-induced damage, which could contribute to the defense mechanisms of non-target organisms against these pollutants.

Indigenous functional microbial communities for the preferential degradation of chloroacetamide herbicide S-enantiomers in soil.

This study investigated indigenous functional microbial communities associated with the degradation of chloroacetamide herbicides acetochlor (ACE), S-metolachlor (S-MET) and their enantiomers in repeatedly treated soils. The results showed that biodegradation was the main process for the degradation of ACE, S-MET and their enantiomers. Eight dominant bacterial genera associated with the degradation were found: Amycolatopsis, Saccharomonospora, Mycoplasma, Myroides, Mycobacterium, Burkholderia, Afipia, and Kribbella. The S-enantiomers of ACE and S-MET were preferentially degraded, which mainly relied on Amycolatopsis, Saccharomonospora and Kribbella for the ACE S-enantiomer and Amycolatopsis and Saccharomonospora for the S-MET S-enantiomer. Importantly, the relative abundances of Amycolatopsis and Saccharomonospora increased by 146.3%-4467.2% in the S-enantiomer treatments of ACE and S-MET compared with the control, which were significantly higher than that in the corresponding R-enantiomer treatments (25.3%-4168.2%). Both metagenomic and qPCR analyses demonstrated that four genes, ppah, alkb, benA, and p450, were the dominant biodegradation genes (BDGs) potentially involved in the preferential degradation of the S-enantiomers of ACE and S-MET. Furthermore, network analysis suggested that Amycolatopsis, Saccharomonospora, Mycoplasma, Myroides, and Mycobacterium were the potential hosts of these four BDGs. Our findings indicated that Amycolatopsis and Saccharomonospora might play pivotal roles in the preferential degradation of the S-enantiomers of ACE and S-MET.

Earthworms accelerated the degradation of the highly toxic acetochlor S-enantiomer by stimulating soil microbiota in repeatedly treated soils.

This study investigated the effects of earthworms on the enantioselective degradation of chloroacetamide herbicide acetochlor with soil microorganisms in repeatedly treated soils. The S-enantiomer degraded more slowly and exerted stronger inhibition on soil microbial functions than the R-enantiomer in single soil system. A synergistic effect was observed between soil microorganisms and earthworms that accelerated the degradation of both the enantiomers, particularly the highly toxic S-enantiomer, which resulted in the preferential degradation of S-enantiomer in soil-earthworm system. Earthworms stimulated five potential indigenous degraders (i.e. Lysobacter, Kaistobacter, Flavobacterium, Arenimonas, and Aquicell), induced two new potential degraders (i.e. Aeromonas and Algoriphagus), and also significantly strengthened the correlations among these seven dominant potential degraders and other microorganisms. Notably, the relative abundances of Flavobacterium and Aeromonas in soil treated with earthworms for S-enantiomer were higher than those for R-enantiomer. Furthermore, earthworms significantly stimulated overall soil microbial activity and improved three microbial metabolic pathways, and xenobiotics biodegradation and metabolism, signal transduction, cell motility, particularly for the S-enantiomer treatment with earthworms, which alleviated the strong inhibition of S-enantiomer on microbial community functions. This study confirmed that earthworms accelerated the degradation of the highly toxic acetochlor S-enantiomer in soil, providing a potential approach in chloroacetamide herbicide-polluted soil remediation.

Enantioselective bioaccumulation and detoxification mechanisms of earthworms (Eisenia fetida) exposed to mandipropamid.

As a novel chiral amide fungicide, the enantioselective behaviors of mandipropamid in the soil environment are unclear. Furthermore, there is a need to understand the stress response mechanisms of soil organisms exposed to mandipropamid isomers. Therefore, the selective bioaccumulation of mandipropamid isomers and detoxification mechanisms of earthworms (Eisenia fetida) were investigated in this study. Our results suggested that the enantioselective bioaccumulation of mandipropamid in earthworms occurred with the preferential enrichment of S-(+)-isomer. The activities of detoxification enzymes, such as cytochrome P450 (CYP450), glutathione-S-transferases (GST), and carboxylesterase (CarE), changed significantly upon exposure to S-(+)- and R-(-)-mandipropamid (particularly for CYP450 and GST). A transcriptome analysis revealed that more differentially expressed genes (DEGs) were observed under S-(+)-isomer exposure (15,798) than those under R-(-)-isomer exposure (12,222), as compared to the control group. These DEGs were mainly enriched in bile secretion and thyroid hormone signaling pathways, which were related to the detoxification process in earthworms. Moreover, the 20 DEGs, which exhibited the most profound changes (such as CYP2 and CYP3A4) in these pathways, were screened, clustered, and observed to be mainly involved in regulating the detoxification function of earthworm cells. These results indicated that detoxification systems played an essential role in the stress response to mandipropamid exposure. Additionally, earthworms were more sensitive to the stress induced by S-(+)-mandipropamid than that induced by R-(-)-mandipropamid. This is the first study to elucidate the mandipropamid detoxification mechanism of earthworms at the enantiomer level, which can be beneficial for remediating chiral pollutants.

Simultaneous Determination of the Residues of Isopyrazam Isomers and Their Metabolites in Soil and Tomatoes by Ultraperformance Liquid Chromatography-Tandem Mass Spectrometry.

An effective and sensitive method for the determination of isopyrazam (IZM) isomers (syn-IZM and anti-IZM) and their metabolites (syn545364 and syn545449) in tomato and soil by ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was developed in the present study. The method showed excellent linearities (R2 = 0.999) at 0.005-5 mg/L. The recoveries were 92.0-107%, and the relative standard deviation (RSD) values were lower than 9.40% in tomato and soil matrices at 0.01, 0.1, and 10 mg/kg. The limits of detection (LODs) of the four compounds ranged from 6.88 × 10-5 to 2.70 × 10-4 mg/kg, while the limits of quantification (LOQs) ranged from 2.20 × 10-4 to 9.20 × 10-4 mg/kg. The storage stability test results showed that syn-IZM, anti-IZM, syn545449, and syn545364 were stable in tomato at -20 °C within 36 weeks, and the maximum degradation rates were 16.0, 12.0, 7.10, and 12.0%, respectively. The field dissipation test results showed that the half-lives of syn-IZM in tomato and soil were 2.60-10.2 and 13.6-33.0 days, respectively, while the half-lives of anti-IZM in soil were 21.7-46.2 days, and no residues of anti-IZM were detected in tomato. The terminal residue test results showed that the residue of syn-IZM and anti-IZM in tomato ranged from <0.0100-0.490 to <0.0100-0.0850 mg/kg. The present results showed that anti-IZM degraded faster than syn-IZM in tomato and soil, and had a lower residue level in tomato.

Enantioselective residues and toxicity effects of the chiral triazole fungicide hexaconazole in earthworms (Eisenia fetida).

The enantioselective toxic effect and environmental behavior of chiral pesticides have attracted increasing research attention. In this study, the enantioselective toxicity and residues of hexaconazole (HEX) in earthworms (Eisenia fetida) were investigated. In the present study, significant enantioselective degradation characteristics were observed in artificial soil with the R-enantiomer preferentially degrading (p < 0.05); however, no significant enantioselective bioaccumulation was observed in the earthworms (p > 0.05). The acute toxicity of S-(+)-HEX was higher than that of R-(-)-HEX in earthworms, with 48-h LC50 values of 8.62 and 22.35 µg/cm2, respectively. At 25 mg/kg, enantiospecific induction of oxidative stress was observed in earthworms; moreover, S-(+)-HEX had a greater influence on the contents of malonaldehyde, cytochrome P450, and 8-hydroxy-2-deoxyguanosine than R-(-)-HEX. These results were consistent with those of the enrichment analysis of differentially expressed genes. The transcriptome sequencing results showed that S-(+)-HEX had a more significant influence on steroid biosynthesis, arachidonic acid metabolism, and cell cycle processes than R-(-)-HEX, leading to abnormal biological function activities. These results indicate that S-(+)-HEX may pose a higher risk to soil organisms than R-(-)-HEX. This study suggests that the environmental risk of chiral pesticides to nontarget organisms should be assessed at the enantiomeric level.

Characterization of a novel carbendazim-degrading strain Rhodococcus sp. CX-1 revealed by genome and transcriptome analyses.

The persistence and ecotoxicity of carbendazim residues pose a potential risk to environmental ecology and human health. Here, a novel and highly efficient carbendazim-degrading bacterium Rhodococcus sp. CX-1, capable of utilizing carbendazim as its sole source of carbon and energy, was isolated from contaminated soil. The biodegradation characteristics and metabolic pathways were studied by mass spectrometry, genomic annotation, and transcriptome analysis. The degradation rate of carbendazim by strain CX-1 was 3.98-9.90 mg/L/h under different conditions, and the optimum degradation conditions were 40 °C and pH 7.0. The addition of carbon sources (glucose, fructose, and sucrose, 100 mg/L) could accelerate carbendazim degradation. HPLC-MS/MS identification suggested that carbendazim is first hydrolyzed into 2-aminobenzimidazole and then to 2-hydroxybenzimidazole, and is ultimately mineralized to carbon dioxide. The genome of strain CX-1 contained 6,511,628 bp nucleotides, 2 linear plasmids, 2 circular plasmids, and 6437 protein coding genes. Genome annotation and transcriptome analysis indicated that carbendazim degradation may be regulated by the degradation genes harbored in the chromosome and in plasmid 2, and two different degradation pathways of carbendazim by imidazole ring cleavage or benzene ring cleavage were predicted. This study provided new insight to reveal the biodegradation mechanism of carbendazim; furthermore, strain CX-1 is a promising bioresource for carbendazim bioremediation.

Enantioselective toxicity and oxidative stress effects of acetochlor on earthworms (Eisenia fetida) by mediating the signaling pathway.

Acetochlor (ACT) as a widely used chiral chloroacetamide herbicide is appropriate to evaluate the potential toxicity in soil ecosystems at enantiomeric level. The acute and subchronic toxicities of R-acetochlor (R-ACT) and S-acetochlor (S-ACT) on earthworms (Eisenia fetida) were investigated in the present study. Residual analyses showed that S-ACT degraded faster than R-ACT in artificial soil with half-lives of 16.5 and 21.7 d, respectively. Additionally, significant enantioselective acute toxicity in earthworms from between S-ACT and R-ACT (p < 0.05) was observed, and the acute toxicity of R-ACT were 1.9 and 1.5 times higher than those of S-ACT in the filter paper test and artificial soil test. The hydroxyl radical (OH-) content, superoxide dismutase (SOD) and antioxidant enzyme catalase (CAT) activities, and cytochrome P450 content in earthworms significantly increased under the influence of ACT enantiomers; however, the acetylcholinesterase (AchE) activity was significantly inhibited after exposure to the two enantiomers. Moreover, lipid peroxidation and DNA damage were induced by ACT enantiomers. The results of transcriptome sequencing indicated that R-ACT induced a stronger oxidative stress effect than S-ACT in earthworms by mediating signaling pathways, which may be the primary reason for the enantioselective toxicity between S-ACT and R-ACT. Overall, the results demonstrated that R-ACT has a higher risk than S-ACT in the soil environment, which is important for understanding the enantioselective behavior of chloroacetamide pesticides.

Transcriptome, bioaccumulation and toxicity analyses of earthworms (Eisenia fetida) affected by trifloxystrobin and trifloxystrobin acid.

As a promising fungicide, the potential environmental risk of trifloxystrobin (TFS) and its main metabolism trifloxystrobin acid (TFSA) in soil environment should be given special attention. The present study investigated the potential risks of TFS and TFSA in soil environment to earthworms (Eisenia fetida) through measuring several biomarkers. Residual analysis showed that TFSA was more stable than TFS in artificial soil with half-lives ranging from 138.6 to 231.0 d and 20.4-24.7 d, respectively. Additionally, the accumulation of TFS in earthworms increased in the beginning and then decreased from day 14, while that of TFSA continuously increased. At concentrations of 4.0 mg/kg and 10.0 mg/kg, the weight and lysosomal membrane stability of earthworms were reduced; however, the superoxide dismutase (SOD) activity, glutathione-S-transferase (GST) activity and malondialdehyde (MDA) content in earthworms were enhanced by TFS and TFSA. Moreover, the growth inhibition effect and the oxidative damage level induced by TFSA to earthworms were higher than those induced by TFS. The transcriptome analysis date indicated that the differentially expressed genes (DEGs) in both TFS and TFSA treatments were mainly enriched in ribosome pathway and lysosome pathway, finally affecting the protein synthesis and proteolysis in earthworms. The findings of the present study indicated that TFSA may pose a higher risk in the soil environment than TFS.

Residue and toxicity of cyantraniliprole and its main metabolite J9Z38 in soil-earthworm microcosms.

As part of a new generation of diamide insecticides, cyantraniliprole has broad application prospects. In the present study, a QuEChERS-UPLC-MS/MS method was established to determine the residues of cyantraniliprole and its main metabolite J9Z38 in soil and earthworms. Moreover, the accumulation and toxicity of cyantraniliprole and J9Z38 in earthworms were evaluated. The present results show that the detection method of cyantraniliprole and J9Z38 has high sensitivity and accuracy, which could be used for the accurate quantification of cyantraniliprole and J9Z38 residues in soil and earthworms. Additionally, cyantraniliprole degraded faster than its main metabolite J9Z38 in the artificial soil. Moreover, the bioenrichment efficiency of cyantraniliprole was higher than J9Z38. The toxicity test result showed that cyantraniliprole and J9Z38 could induce oxidative stress effect in earthworms from 5.0 mg/kg, finally resulting in cellular damage. Moreover, the oxidative damage degree induced by cyantraniliprole was higher than J9Z38. Combining the results of residue test and toxicity test, although cyantraniliprole degraded faster than its main metabolite J9Z38 in the artificial soil, its risk to earthworms was higher than J9Z38.

The Toxic Effects of Sulfoxaflor Induced in Earthworms (Eisenia fetida) under Effective Concentrations.

Sulfoxaflor is a new kind of neonicotinoid insecticide that is used to control sap-feeding insect pests. In this study, a hazard assessment of sulfoxaflor on soil invertebrate earthworms was performed under effective concentrations. The results showed that different exposure times and doses had significant influence on the toxicity of sulfoxaflor. Sulfoxaflor degraded quickly in artificial soil with a degradation rate of 0.002-0.017 mg/(kg·d) and a half-life of 12.0-15.4 d. At 0.5 mg/kg and 1.0 mg/kg, the ·OH- content, antioxidant enzyme activeities, thiobarbituric acid reactive substances (TBARS) content and 8-OHdG content had significant differences compared to those in the control group. On the 56th day, significant differences were only observed in the Glutathione S-transferase enzyme (GST) activity and 8-OHdG content at 1.0 mg/kg compared to those in the control group due to the degradation of sulfoxaflor. This indicated that the risk of sulfoxaflor to earthworms was reduced because it was easily degraded in soil. However, because sulfoxaflor is a super toxic pollutant to earthworms, high concentrations of sulfoxaflor should not be released into the soil environment.

Dissipation of chlorothalonil in the presence of chlortetracycline and ciprofloxacin and their combined effects on soil enzyme activity.

The long-term application of substantial amounts of fungicides and antibiotic-polluted organic manure (OM) in greenhouse has caused the co-existence of fungicides and antibiotics in soils. However, little is known about the effects of antibiotics on the persistence of fungicides in soils or their combined effects on soil enzyme activity. In this study, fungicide chlorothalonil (CTL) alone and in combination with antibiotic chlortetracycline (CTC) or ciprofloxacin (CIP) were repeatedly added to OM-amended soil to investigate the changes in the residual characteristics of CTL and in soil dehydrogenase and urease activity. The results showed that CTL rapidly dissipated in soils with the corresponding half-lives of 0.9-3.2, which initially increased, then decreased and finally stabilized with an increased treatment frequency. The dissipation of CTL was inhibited by CTC and CIP during the first several treatments. The soil dehydrogenase and urease activity in CTL-treated soils was inhibited during the first six treatments and then recovered afterwards. Compared with the OM-amended soil+CTL treatment, the OM-amended soil+CTL+CTC and OM-amended soil+CTL+CIP treatments had stronger inhibitory effects on soil enzyme activity during the first six repeated treatments but exhibited slight stimulating effects afterwards. Therefore, the results obtained in this study suggested that the long-term co-existence of CTL, CTC, and CIP altered the dissipation characteristics of CTL in soil and affected the soil enzyme activity levels. The prudent application of large and frequent of fungicides and OM-containing antibiotic residues in greenhouses should therefore be carefully considered in order to reduce the long-term combined pollution in soils.