The influence of oxytetracycline on the degradation and enantioselectivity of the chiral pesticide beta-cypermethrin in soil

Antibiotics alter the metabolic profile of metolachlor in soil-plant system by disturbing the detoxifying process and oxidative stress

Antibiotics are widely detected in farmland, which may influence the environmental behavior and risks of the coexisting pesticide. In this work, the effects of antibiotics on metolachlor transformation in soil-pea and the risk of metolachlor to earthworm were assessed, and the mechanism was explored in view of detoxifying process and oxidative stress. Antibiotics affected not the degradation rate but the metabolic profile of metolachlor. In soil, the content of metabolites oxaloacetic acid (OA) and ethane sulfonic acid (ESA) was decreased and dechlorometolachlor (DCL) was increased by antibiotics. In pea, the accumulation of metolachlor, DCL and ESA was decreased, while OA was increased by antibiotics. The changed transformation of metolachlor affected the risk to earthworm according to risk quote assessment. In further research, it was found that cytochrome P450 (CYP450) enzyme was reduced by 12.3% - 30.4% in soil and 12.4% - 23.6% in pea, which might due to excessive ROS accumulation induced by antibiotics, thus affecting the transformation and metabolite profile of metolachlor in soil-plant system.

Toxic effect and mechanism of β-cypermethrin and its chiral isomers on HTR-8/SVneo cells

Beta-cypermethrin (β-CYP) consists of four chiral isomers, acting as an environmental estrogen and causing reproductive toxicity, neurotoxicity, and dysfunctions in multiple organ systems. This study investigated the toxic effects of β-CYP, its isomers, metabolite 3-phenoxybenzoic acid (3-PBA), and 17β-estradiol (E2) on HTR-8/SVneo cells. We focused on the toxic mechanisms of β-CYP and its specific isomers. Our results showed that β-CYP and its isomers inhibit HTR-8/SVneo cell proliferation similarly to E2, with 100 μM 1S-trans-αR displaying significant toxicity after 48 h. Notably, 1S-trans-αR, 1R-trans-αS, and β-CYP were more potent in inducing apoptosis and cell cycle arrest than 1R-cis-αS and 1S-cis-αR at 48 h. AO/EB staining and flow cytometry indicated dose-dependent apoptosis in HTR-8/SVneo cells, particularly at 100 μM 1R-trans-αS. Scratch assays revealed that β-CYP and its isomers variably reduced cell migration. Receptor inhibition assays demonstrated that post-ICI 182780 treatment, which inhibits estrogen receptor α (ERα) or estrogen receptor β (ERβ), β-CYP, its isomers, and E2 reduced HTR-8/SVneo cell viability, whereas milrinone, a phosphodiesterase 3 A (PDE3A) inhibitor, increased viability. Molecular docking studies indicated a higher affinity of β-CYP, its isomers, and E2 for PDE3A than for ERα or ERβ. Consequently, β-CYP, its isomers, and E2 consistently led to decreased cell viability. Transcriptomics and RT-qPCR analyses showed differential expression in treated cells: up-regulation of Il24 and Ptgs2, and down-regulation of Myo7a and Pdgfrb, suggesting the PI3K-AKT signaling pathway as a potential route for toxicity. This study aims to provide a comprehensive evaluation of the cytotoxicity of chiral pesticides and their mechanisms.

Oxytetracycline Increases the Residual Risk of Imidacloprid in Radish (Raphanus sativus) and Disturbs the Plant-Rhizosphere Microbiome Holobiont Homeostasis

Antibiotics can be accidentally introduced into farmland by wastewater irrigation, and the environmental effects are still unclear. In this study, the effects of oxytetracycline on the residue of imidacloprid in soil and radishes were investigated. Besides, the rhizosphere microbiome and radish metabolome were analyzed. It showed that the persistence of imidacloprid in soil was unchanged, but the content of olefin-imidacloprid was increased by oxytetracycline. The residue of imidacloprid in radishes was increased by nearly 1.5 times, and the hazard index of imidacloprid was significantly raised by 1.5-4 times. Oxytetracycline remodeled the rhizosphere microbiome, including Actinobe, Elusimic, and Firmicutes, and influenced the metabolome of radishes. Especially, some amino acid metabolic pathways in radish were downregulated, which might be involved in imidacloprid degradation. It can be assumed that oxytetracycline increased the imidacloprid residue in radish through disturbing the plant-rhizosphere microbiome holobiont and, thus, increased the pesticide dietary risk.

Co-existing antibiotics alter the enantioselective dissipation characteristics of zoxamide and drive combined impact on soil microenvironment

Co-existence of antibiotics (ABX) in soil may expand the environmental harm of pesticide pollution. Our study investigated the combined effects of five antibiotics chlortetracycline (CTC), oxytetracycline (OTC), tetracycline (TC), sulfamethoxazole (SMX), enrofloxacin (ENR) on enantioselective fate of zoxamide (ZXM) and soil health. The results showed that S-(+)-ZXM preferentially dissipated in soil. ABX prolonged dissipation half-life and reduced enantioselectivity of ZXM. Soil was detected to be more acidic after long-term treatment of ZXM and ABX. Lowest soil available N, P, K were found in ZXM + SMX, ZXM + OTC and ZXM + SMX groups at 80 days, respectively. ABX had demonstrated effective promotion of catalase (S-CAT), urease (S-UE) and negative impact on dehydrogenase (S-DHA), sucrase (S-SC) activities. Bacteria Lysobacter, Sphingomonas and fungus Mortierella were identified as the most dominant genera, which possessed as potential microbial resources for removal of composite pollution from ZXM and ABX. SMX and TC, SMX, ENR, respectively, contributed to the alteration of bacteria and fungi community abundance. Soil acidity, available N and enzyme activity showed stronger correlations with bacteria and fungi compared to other environmental factors. Our findings highlighted the interactions between ZXM and ABX from the perspective of soil microenvironment changes. Moreover, a theoretical basis for the mechanism was actively provided.

Enantioselective Behaviors of Chiral Pesticides and Enantiomeric Signatures in Foods and the Environment

Unreasonable application of pesticides may result in residues in the environment and foods. Chiral pesticides consist of two or more enantiomers, which may exhibit different behaviors. This Review intends to provide progress on the enantioselective residues of chiral pesticides in foods. Among the main chiral analytical methods, high performance liquid chromatography (HPLC) is the most frequently utilized. Most chiral pesticides are utilized as racemates; however, due to enantioselective dissipation, bioaccumulation, biodegradation, and chiral conversion, enantiospecific residues have been found in the environment and foods. Some chiral pesticides exhibit strong enantioselectivity, highlighting the importance of evaluation on an enantiomeric level. However, the occurrence characteristics of chiral pesticides in foods and specific enzymes or transport proteins involved in enantioselectivity needs to be further investigated. This Review could help the production of some chiral pesticides to single-enantiomer formulations, thereby reducing pesticide consumption as well as increasing food production and finally reducing human health risks.

Effects of the presence of triclocarban on the degradation and migration of co-occurring pesticides in soil

Triclocarban (TCC), a bactericide widely used in personal care products, is frequently detected in soil and surface water, which may affect the environmental behavior of other environmental pollutants by changing the community structure of environmental microorganisms. This work evaluated the effects of TCC on the degradation and migration of seven herbicides and five fungicides in soil under co-occurrence conditions. TCC significantly increased the persistence of the pesticides in soil, and this effect increased with TCC concentration. For example, the half-life of metolachlor, atrazine, metribuzin, and metamitron increased 44%, 38%, 153%, and 33%, respectively, with 10 mg/kg TCC and increased 60%-640% with 100 mg/kg TCC. After 90 days, the residue of the pesticides in soil treated with TCC was significantly elevated relative to the control. TCC treatment could also increase the potential leaching risk of the herbicides in the soil, as indicated by an increased Groundwater Ubiquity Score (GUS) index. The reduced abundance of soil bacteria by TCC might be an essential reason for the impacts on the environmental behavior of the pesticides. This study confirmed that TCC could slow down the degradation of pesticides in soil, increase their persistence and even affect the leaching behavior, thus influencing the risks of the pesticides to the environment.

Tetracycline biotransformation by a novel bacterial strain Alcaligenes sp. T17

Comprehensive knowledge on the biotransformation of tetracycline (TC) is critical for the improvement of TC removal in the bioremediation process. This work isolated a novel TC-degrading bacterial strain Alcaligenes sp. T17 and explored its degradation ability under different conditions. Temperature and pH could affect the degradation efficiency, and higher temperature as well as neutral and weakly acidic conditions were conducive to the biotransformation. Response surface methodology predicted the maximum degradation rate of TC (94.35%) under the condition of 25.15 mg/L TC, pH 7.23, and inoculation dosage 1.17% at 40 °C. According to the result of disk diffusion tests, the biodegradation products had lower antimicrobial potency than the parent compound. Five potential biodegradation products were identified, and a possible degradation pathway (degrouping, oxidation and ring-opening) was proposed. The draft genome of strain T17 was also determined. Genomic analysis indicated that strain T17 harbored multiple genes that participated in the metabolism of aromatic compounds as well as genes encoding oxygenases. These functional genes may be relevant to TC biotransformation. This study could provide new insights towards the biotransformation of TC mediated by bacteria.

Assessment of the eco-toxicological effects in zoxamide polluted soil amended with fertilizers-An indoor evaluation

Zoxamide is a benzamide fungicide applied to control diseases caused by oomycete fungi. Fertilizers are important agricultural supplies to adjust soil properties and increase nutrition. To investigate the impact of zoxamide and seven fertilizers urea, phosphate fertilizer, potash fertilizer, compound fertilizer, organic fertilizer, vermicompost and soya bean cakes on the soil environment, the enantioselective dissipation characteristics of zoxamide, soil enzyme activities, pH and N, P nutrition changes were comprehensively analyzed in our present study. The enantioseparation method was successfully validated to quantify the zoxamide enantiomers in soil by HPLC using Chiral NQ (2)-RH column. Our results demonstrated that the R-(-)- and S-(+)-zoxamide half dissipated in the range of 10.88-17.81 and 8.05-14.41 days, respectively. S-(+)-zoxamide disappeared faster in soil. The vermicompost accelerated the dissipation rate of S-(+)-zoxamide, while urea, phosphate, organic and vermicompost fertilizer increased the dissipation selectivity. Zoxamide and fertilizers other than urea caused soil acidification during 80 days. Zoxamide was beneficial to soil catalase, instead inhibited soil urease, dehydrogenase activities and available phosphorus content. No significant effects on sucrase activity and available nitrogen content were found by zoxamide. Vermicompost and soya bean cakes had lasting and outstanding performance in efficiently improving soil enzyme activity and N, P nutrition. The comprehensive understanding of the ecological impact induced by chiral pesticide enantiomers and fertilizers on soil is vital to ensure the sustainable development and safety of agricultural production.

Co-exposure of Monensin Increased the Risks of Atrazine to Earthworms

Antibiotics could enter farmlands through sewage irrigation or manure application, causing combined pollution with pesticides. Antibiotics may affect the environmental fate of pesticides and even increase their bioavailability. In this study, the influence of monensin on the degradation, toxicity, and availability of atrazine in soil-earthworm microcosms was investigated. Monensin inhibited the degradation of atrazine, changed the metabolite patterns in soil, and increased the bioavailability of atrazine in earthworms. Atrazine and monensin had a significant synergistic effect on earthworms in the acute toxic test. In long-term toxicity tests, co-exposure of atrazine and monensin also led to worse effects on earthworms including oxidative stress, energy metabolism disruption, and cocoon production compared to single exposure. The expression of tight junction proteins was down-regulated significantly by monensin, indicating that the intestinal barrier of earthworms was weakened, possibly causing the increased bioavailability of atrazine. The expressions of heat shock protein 70 (Hsp70) and reproductive and ontogenetic factors (ANN, TCTP) were all downregulated in binary exposure, indicating that the resilience and cocoon production of earthworms were further weakened under combined pollution. Monensin disturbed the energy metabolism and weakened the intestinal barrier of earthworms. These results showed that monensin increased the risks of atrazine in agricultural areas.

Enantioselective degradation of prothioconazole in soil and the impacts on the enzymes and microbial community

In this work, the stereoselective degradation of prothioconazole in five soils was investigated and the metabolite prothioconazole-desthio was determined. The effects of prothioconazole on soil enzymes activities and microbial community were also studied. The dissipation of prothioconazole fitted with a first-order kinetic equation with half-lives ranging from 3.45 to 9.90 days. In addition, R-prothioconazole degraded preferentially than S-prothioconazole in all soils with EF values >0.5. Prothioconazole-desthio formed rapidly with preference in R-enantiomer, and the concentration kept at a considerable level even at the end of the incubation, indicating it was relatively persistent in soil. Prothioconazole and its metabolite inhibited the activity of dehydrogenase, catalase and urease in soils, and could affect the diversity of the soil microbiota as well. Redundancy analysis (RDA) and Spearman analysis showed the abundance of Proteobacteria, Fusobacteria, Firmicutes, Thaumarchaeota, Saccharibacteria, Chloroflexi, Chlorobi, Actinobacteria and Nitrospirae might be related to the enantioselective degradation. The work was helpful for understanding the environmental behavior of the fungicide prothioconazole and its primary metabolite on an enantiomeric level.

A comprehensive review on biodegradation of tetracyclines: Current research progress and prospect

The release of tetracyclines (TCs) in the environment is of significant concern because the residual antibiotics may promote resistance in pathogenic microorganisms, and the transfer of antibiotic resistance genes poses a potential threat to ecosystems. Microbial biodegradation plays an important role in removing TCs in both natural and artificial systems. After long-term acclimation, microorganisms that can tolerate and degrade TCs are retained to achieve efficient removal of TCs under the optimum conditions (e.g. optimal operational parameters and moderate concentrations of TCs). To date, cultivation-based techniques have been used to isolate bacteria or fungi with potential degradation ability. Moreover, the biodegradation mechanism of TCs can be unveiled with the development of chemical analysis (e.g. UPLC-Q-TOF mass spectrometer) and molecular biology techniques (e.g. 16S rRNA gene sequencing, multi-omics sequencing, and whole genome sequencing). In this review, we made an overview of the biodegradation of TCs in different systems, refined functional microbial communities and pure isolates relevant to TCs biodegradation, and summarized the biodegradation products, pathways, and degradation genes of TCs. In addition, ecological risks of TCs biodegradation were considered from the perspectives of metabolic products toxicity and resistance genes. Overall, this article aimed to outline the research progress of TCs biodegradation and propose future research prospects.

New Role for a Commercially Available Bioinsecticide: Bacillus thuringiensis Berliner Biodegrades the Pyrethroid Cypermethrin

The microbial diversity of several environments has been explored by researchers for the biodegradation of pyrethroids. In this study, a new approach was employed aiming at the use of Bacillus thuringiensis Berliner, a strain commercially available as bioinsecticide, for Cypermethrin (Cyp) biodegradation. This bacterial strain grew in the presence of Cyp and biodegraded this xenobiotic in a liquid medium. A central composite design for surface response methodology was employed for biodegradation. Under optimized conditions (50 mg·L^-1 of Cyp, pH 8.5, 37 °C), 83.5% biodegradation was determined with the production of 12.0 ± 0.6 mg·L^-1 3-phenoxybenzoic acid after 5 days. Moreover, a biodegradation pathway with the 18 compounds identified by GC-MS and LC-MS/MS was proposed. Experiments in soil for 28 days at 30 °C were performed, and 16.7% Cyp degradation was determined under abiotic conditions, whereas 36.6 ± 1.9% biodegradation was observed for B. thuringiensis Berliner with the native microbiome, indicating that bioaugmentation with this strain promoted a significant increase in the Cyp decontamination. Therefore, B. thuringiensis Berliner can act as biodegrader agent and insecticide at the same time, promoting decontamination of chemicals as Cyp while maintaining the protection of crops against insects. Moreover, B. thuringiensis species can produce bacteriocins with antifungal activity, which may increase agricultural productivity.

Azoxystrobin dissipation and its effect on soil microbial community structure and function in the presence of chlorothalonil, chlortetracycline and ciprofloxacin

The residual characteristics and the adsorption-desorption behaviors of azoxystrobin (AZO) as well as the soil ecological effects in the individual repeated treatments of AZO and its combination with chlorothalonil (CTL), chlortetracycline (CTC) and ciprofloxacin (CIP) were systematically studied in organic manure (OM)-amended soil under laboratory conditions. The presence of CTL, CTC, and CIP, both individually and combined, decreased the sorption affinity of AZO with the Freundlich adsorption and desorption coefficient decreasing by 0.3-24.2%, and CTC and CIP exhibited greater adverse effects than CTL. AZO dissipated slowly and the residues significantly accumulated during ten repeated treatments. The dissipation of AZO was inhibited to different degrees in the combined treatments. Biolog analysis revealed that the soil microbial functional diversity in the OM-soil + AZO and OM-soil + AZO + CTL treatments was higher than that in the OM-soil treatment during the former three repeated treatments, but which was inhibited during the latter seven repeated treatments. The soil microbial functional diversity in the OM-soil + AZO + CTC, OM-soil + AZO + CIP and OM-soil + AZO + CTL + CTC + CIP treatments was inhibited during the ten repeated treatments compared with OM-soil treatment. Metagenomic results showed that all repeated treatments significantly increased the relative abundance of Actinobacteria, but significantly decreased that of Proteobacteria and Firmicutes during the ten repeated treatments. Furthermore, the relative abundance of soil dominant bacterial genera Rhodococcus, Mycobacterium and Arthrobacter in all the repeated treatments significantly increased by 1.5-1283.9% compared with the OM-soil treatment. It is concluded that coexistence of CTL, CTC and CIP, both individually and combined, with AZO can inhibit the dissipation of AZO, reduce the adsorption affinity of AZO on soil, and alter the soil microbial community structure and functional diversity.