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An unprecedented electrochemical trifluoromethylation/SO2 insertion/cyclization process has been achieved in an undivided cell in an atom‐economic fashion. The protocol relies on tandem cyclization of N‐cyanamide alkenes by using Langlois' reagent as a source of both CF3 and SO2 under direct anodically oxidative conditions, in which two C−C bonds, two C−X bonds (N−S and S−C), and two rings were formed in a single operation. This transformation enabled efficient construction of various trifluoromethylated cyclic N‐sulfonylimines from readily accessible materials. [ABSTRACT FROM AUTHOR]

Abstract The chiral signatures and environmental behaviors of chiral polychlorinated biphenyls (PCBs) have been extensively studied. However, information regarding chiral PCBs in invertebrates, especially earthworms, is limited. This study aimed to investigate the stereoselective bioaccumulation, elimination, and biotransformation of chiral PCBs 95 and 149 in an earthworm-soil system. Preferential enrichment of (+)-atropisomers and elimination of (−)-atropisomers were observed, for both PCBs 95 and 149, during the uptake and elimination phases, respectively, leading to higher enantiomer fractions (EFs). A significant linear correlation between the total concentrations of chiral PCBs and EF values was found in earthworms. The EF values increased with the increase in exposure time and further increased during the elimination phase, indicating the biotransformation of chiral PCBs. Hydroxylated metabolites of PCB 95 were found in earthworms for the first time, thus verifying the ability of earthworms to metabolize chiral PCBs. However, no methylsulfonyl metabolites were observed for PCBs 95 and 149. These findings might be helpful for understanding the biological processes of chiral PCBs in species at lower trophic levels. Highlights • Stereoselective bioaccumulation of chiral PCBs 95 and 149 in earthworms was investigated. • EFs increased during the uptake phase and further increased during the elimination phase. • Linear correlations were observed between total PCB concentrations and EFs. • Hydroxylated metabolites of PCB 95 were found in earthworms. [ABSTRACT FROM AUTHOR]

Abstract The ecological toxicity of hexabromocyclododecane (HBCD) on animals, including fish and mice, has been reported, but its effects in plants, particularly its toxic mechanism, have rarely been investigated. An untargeted metabolomics approach for comprehensive assessment was selected to study the alterations in the metabolic profiles in pak choi leaves induced by exposure to trace-level amounts of HBCD diastereomers over 30 days. A supervised orthogonal partial least-squares-discriminant analysis (OPLS-DA) was performed to investigate differences between the HBCD and control groups. The discriminating metabolites were identified using public databases. The results indicated that the toxicity of the HBCD diastereomers was ordered as γ-HBCD > α-HBCD > β-HBCD. 13 metabolites were identified as potential biomarkers to discriminate the presence of HBCD toxicity. The lipid, carbohydrate, nucleotide and amino acid metabolic pathways affected were found in accordance with animals and humans, and also HBCD could induce the interference of the secondary metabolite pathways. The system of the stress defences was activated, including signalling pathway, antioxidant defence system, shikimate and phenylpropanoid metabolism. The carbohydrate and amino acid metabolism were disturbed by HBCD intervention, and the lipid, amino acid and secondary metabolite metabolism were regulated for HBCD stress prevention. These results provide insights into the mechanism and degree of HBCD phytotoxicity. Graphical abstract Image 1 Highlights • The phytotoxicity of HBCD diastereomers was assessed by metabolomics approach. • 13 potential biomarkers were used to discriminate the presence of HBCD toxicity. • HBCD induced interference of the biosynthesis of other secondary metabolites. • A suggestion was provided on the mechanism of toxicity. The mechanism of HBCD phytotoxicity was suggested at metabolic level. [ABSTRACT FROM AUTHOR]

Stereoselective bioaccumulation, elimination, metabolomic and lipidomic responses of earthworm Eisenia fetida exposed to chiral polychlorinated biphenyl (PCB) 91 in an earthworm-soil system were investigated. Preferential bioaccumulation of (−)-PCB 91 and elimination of (+)-PCB 91 were observed following 50 and 500 μg/kg dwt exposures. Enantiomer fraction (EF) values decreased over time during the uptake and elimination periods. Metabolomics and lipidomics techniques based on ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS) revealed significant changes in 108 metabolites after earthworms exposure to (+)-, (−)-, and (±)-PCB 91, compared to control groups. Forty two of these metabolites were identified as amino acids, nucleosides, fatty acids, dicarboxylic acids, vitamins or others. Lysophospholipids including six lysophosphatidylcholines (LPC), six lysophosphatidylethanolamine (LPE), eight lysophosphatidylinositol (LPI) and five lysophosphatidylserine (LPS) were also differentially expressed between exposure and control groups. Alterations in the levels of metabolites and lipids indicated stereoselective effects of chiral PCB 91 on earthworm amino acid, energy, and nucleotide metabolism, neurodevelopment and gene expression. Overall, the effects of (+)-PCB 91 were more pronounced than that of (−)- and (±)-PCB 91. [ABSTRACT FROM AUTHOR]

Abstract: BACKGROUND: The dissipation behavior, pre‐harvest interval and dietary risk of carbosulfan, dimethoate, and their relevant metabolites were investigated in greenhouse cucumber in Tianjin, northern China, to ensure raw consumption safety. RESULTS: Carbosulfan was metabolized to carbofuran, dibutylamine, 3‐hydroxycarbofuran and 3‐ketocarbofuran, and dimethoate was degraded to omethoate in cucumber fruits and leaves. The dissipation of carbosulfan, carbofuran, 3‐hydroxycarbofuran and dimethoate fitted first‐order kinetics well, with R2 ranging from 0.912 to 0.992, and their half‐lives were 2.6, 2.7, 2.4 and 5.2 days in cucumber fruits and 2.8, 3.0, 4.6 and 2.5 days in leaves, respectively. The estimated daily intakes of the active ingredients and their relevant metabolites were 0.1–4% of the corresponding acceptable daily intakes. Acute oral exposure to carbofuran (a metabolite of carbosulfan) represented 367% of the acute reference dose (ARfD) for 1–6‐year‐old Chinese children and 227% for the general Chinese population. CONCLUSION: A minimum pre‐harvest interval of 12 days for carbosulfan is proposed to ensure safe consumption of cucumber. The slow dissipation rate of omethoate in cucumber reveals that a longer pre‐harvest interval (≥ 27 days) is necessary to prevent dietary risk when dimethoate is applied to cucumber. © 2018 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The increasing use of antibiotics has caused substantial environmental problems, which are a matter of great concern. The aim of this work was to develop a quick, easy, cheap, effective, rugged, and safe method for 20 antibiotic residues in soil. The developed method is based on extraction with acetonitrile and phosphate buffer, clean up with dispersive solid-phase extraction adsorbent using primary secondary amine, octadecylsilane, followed by liquid chromatography with tandem mass spectrometry determination. We optimized different extraction methods and the ratio of cleanup adsorbents to achieve good recoveries at seven spiking levels that ranged from 61.4 to 118.9% with a relative standard deviation below 20% (n = 5). The method quantification limit was in the range of 2-5 µg/kg for most analytes. Good linear regression coefficients greater than 0.990 were obtained. This method was applied for the analysis of real agricultural soil samples, confirming the feasibility of the method. [ABSTRACT FROM AUTHOR]

In this research, 10 chiral pesticides in fruits and vegetables were simultaneously determined using chiral triple quadrupole-linear ion trap hybrid (LC-QqLIT). The QuEChERS method was applied for sample preparation, and an enhanced product ion (EPI) scan was used to acquire tandem (MS/MS) spectra for the library search. Parameters including limit of detection (LOD), limit of quantification (LOQ), linearity, relative standard deviation (RSD), and matrix effects were evaluated in five representative matrices (strawberry, leek, cowpea, tomato, and eggplant). Good linearity with coefficient of determination (r2) ≥0.997 was obtained for all 20 enantiomers in these five matrices over the range from 1.0 to 250 µg L-1. All the recoveries at 5 and 50 µg kg-1 ( n = 5) ranged between 70% and 120% with RSD below 20%, indicating satisfactory precision. The LOQ for the enantiomers ranged between 0.05 and 1 µg kg-1. Based on the proposed method, 135 commonly consumed fruits and vegetables taken from markets in Guizhou province, China, were analyzed. degradation for the selected chiral pesticides was observed in most of the positive samples. Chirality 27:958-964, 2015. © 2015 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Soil and earthworms are important objects in soil pollution assessment and environmental behavior and toxicity study for polychlorinated biphenyls. Accelerated solvent extraction and solid-phase extraction are generally required for the extraction and clean-up of polychlorinated biphenyls in soil and earthworm, which are tedious and time-consuming. In this work, a modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) procedure combined with gas chromatography and triple quadrupole mass spectrometry was developed for the determination of 20 selected polychlorinated biphenyl congeners in soil and earthworm. Different extraction times, solvents, and clean-up adsorbents were compared and optimized. The average recoveries from spiked soils ranged between 70 and 120% with satisfactory relative standard deviations for all the polychlorinated biphenyls. In earthworm, the recoveries of polychlorinated biphenyls 180, 183, and 189 were relatively low (< 70% in some spiking levels) compared to that of the other polychlorinated biphenyls. The limits of quantification were in the range of 0.01-0.05 ng/g. The method was successfully applied to the analysis of 66 agricultural soils. To our knowledge, a combined method based on QuEChERS for the determination of polychlorinated biphenyls in soil and earthworms has not been published before. The procedure proved to be simple, sensitive, efficient, and environmentally friendly. [ABSTRACT FROM AUTHOR]

A new method for simultaneous determination of 36 pesticides, including 15 organophosphorus, six carbamate, and some other pesticides in soil was developed by liquid chromatography with tandem quadruple linear ion trap mass spectrometry. The extraction and clean-up steps were optimized based on the quick, easy, cheap, effective, rugged, and safe method. The data were acquired in multiple reaction monitoring mode combined with enhanced product ion to increase confidence of the analytical results. Validation experiments were performed in soil samples. The average recoveries of pesticides at four spiking levels (1, 5, 50, and 100 μg/kg) ranged from 63 to 126% with relative standard deviation below 20%. The limits of detection of pesticides were 0.04-0.8 μg/kg, and the limits of quantification were 0.1-2.6 μg/kg. The correlation coefficients ( r2) were higher than 0.990 in the linearity range of 0.5-200 μg/L for most of the pesticides. The method allowed for the analysis of the target pesticides in the lower μg/kg concentration range. The optimized method was then applied to the test of real soil samples obtained from several areas in China, confirming the feasibility of the method. [ABSTRACT FROM AUTHOR]

A simple and high-throughput multiresidue pesticide analysis method was developed and validated for 219 pesticides in cereals (corn, wheat flour and rice) based on QuEChERS (quick, easy, cheap, effective, rugged, and safe) procedure combined with gas chromatography–triple quadrupole mass spectrometry (GC–MS/MS). Different buffer system (acetate- and citrate-buffered) and sample to solvent ratios (sample amount) were compared in the modified QuEChERS procedure to get better recovery and clean-up results. The limits of quantification (LOQ) ranged between 5 and 50 μg kg − 1 , and for the majority of the pesticides the LOQ were 5 μg kg − 1 , which were below the regulatory maximum residue limits. The coefficient of determination ( r 2 ) was >0.99 within the calibration linearity range of 2–200 μg kg − 1 for the majority of the pesticides. Most recoveries at 5, 10, 20, 50, 100 and 200 μg kg − 1 were in the range 70–120% ( n = 6) with associated RSDs < 20% indicating satisfactory accuracy. [ABSTRACT FROM AUTHOR]

In this paper, a new ionic-liquid-functionalized magnetic material was prepared based on the immobilization of an ionic liquid on silica magnetic particles that could be successfully used as an adsorbent for the magnetic SPE of five sulfonylurea herbicides (bensulfuron-methyl, prosulfuron, pyrazosulfuron-ethyl, chlorimuron-ethyl and triflusulfuron-methyl) from environmental water samples. The main parameters affecting the extraction efficiency such as desorption conditions, sample pH, extraction time and so on, were optimized using the Taguchi method. Good linearities were obtained with correlation coefficients ranging from 0.9992 to 0.9999 in the concentration range of 0.1-50 μg L−1 and the LODs were 0.053-0.091 μg L−1. Under the optimum conditions, the enrichment factors of the method were 1155-1380 and the recoveries ranged from 77.8 to 104.4%. The proposed method was reliable and could be applied to the residue analysis of sulfonylurea herbicides in environmental water samples (tap, reservoir and river). [ABSTRACT FROM AUTHOR]

Abstract: A magnetic solid phase extraction (MSPE) method coupled with high-performance liquid chromatography (HPLC) was proposed for the determination of five sulfonylurea herbicides (bensulfuron-methyl, prosulfuron, pyrazosulfuron-ethyl, chlorimuron-ethyl and triflusulfuron-methyl) in environmental water samples. The magnetic adsorbent was prepared by incorporating Fe3O4 nanoparticles and surfactant into a silica matrix according to a sol–gel procedure, which can provide surfactant free extracts during the eluting step to avoid chromatographic interference. The prepared adsorbent was used to extract the sulfonylurea herbicides in several kinds of water samples. The main factors affecting the extraction efficiency, including desorption conditions, extraction time, sample volume, and sample solution pH were optimized. Under the optimum conditions, good linearity was obtained within the range of 0.2–50.0μgL−1 for all analytes, with correlation coefficients ranging from 0.9993 to 0.9999. The enrichment factors were between 1200 and 1410, and the limits of detection were between 0.078 and 0.10μgL−1. The proposed method was successfully applied in the analysis of sulfonylurea herbicides in environmental samples (tap, reservoir, river, and rice field). The recoveries of the method ranged between 80.4% and 107.1%. This study reported for the first time the use of MSPE procedure in the preconcentration of sulfonylurea herbicides in environmental samples. The procedure proved to be efficient, environmentally friendly, and fast. [Copyright &y& Elsevier]

The ecotoxicity of perfluorooctane sulfonate (PFOS) is complex and has been reported in animals (including fish and mice), but the effects of PFOS in plants, especially the toxic mechanisms, have rarely been studied. High-throughput nontargeted metabolomics methods for comprehensive assessment were selected to study changes in metabolic characteristics in Arabidopsis thaliana leaves by exposure to different concentrations of PFOS throughout the growth period (30 days). All the metabolites were analyzed by PCA and OPLS-DA methods, by the cutoff of VIP and p -value, 53 biomarkers were found and significantly regulated, all amino acids except glutamate were inhibited and probably associated with binding to protein, auxin and cytokinin of phytohormones were significantly down-regulated. In response mechanism to oxidative stress from PFOS, the phenylpropanoid pathway were fully activated to form several polyphenols and further enhanced into several flavonoids against the reactive oxygen species (ROS) as the primary defend pathway, in addition, ascorbate, trehalose and nicotinamide also were activated and help decrease the damage from oxidative stress. These results provide insights into the mechanism underlying the phytotoxicity of PFOS. Unlabelled Image • Phytotoxicity of PFOS was assessed by metabolomics approach. • PFOS caused many amino acids down-regulation. • PFOS activated the phenylpropanoid and shikimate pathways. • PFOS showed inhibitory effects on auxins and cytokinins. [ABSTRACT FROM AUTHOR]

The use of the chiral triazole fungicide cis -epoxiconazole in agricultural production continues to increase; however, little is known about the stereoselective and toxic responses of soil microorganisms to cis -epoxiconazole in the soil microenvironment. High-throughput sequencing and metabolomics were integrated to investigate the stereoselective response of soil microbial community structure, metabolic profile to cis -epoxiconazole exposure, and the correlation between the microbiomes and different metabolites. Soil microbial community structure and soil metabolic profile were significantly altered and exhibited significant enantioselectivity. The alpha diversity (Chao, Shannon, and Simpson diversity) of bacterial and fungus was not significantly affected, whereas the beta diversity (Bray-Curtis dissimilarity and PLS-DA) of bacterial and fungus was significantly altered in treatment of cis -epoxiconazole and its enantiomers (p -value < 0.05). The variation in bacterial and fungus community structure was the highest under (+)-enantiomer exposure, followed by exposure to racemate and (−)-enantiomer. Soil metabolomic analysis revealed that exposure to high or low doses of cis -epoxiconazole and its enantiomers resulted in different degrees of reprogramming of the soil metabolic pool. The 39 significantly changed metabolites mainly included small molecular organic acids, amino acids and their intermediates, and purine and adenosine intermediates. Six metabolic pathways were significantly disrupted. Different correlation patterns were observed between the significantly altered metabolites and microbes (p -value < 0.05) by Pearson correlation-based analysis. In conclusion, as xenobiotic pollutant, epoxiconazole altered the structure and metabolism of soil microorganisms with significant stereoselectivity mainly driven by 2R, 3S-(+)- cis -epoxiconazole. This study provided a more robust assessment of the risks of epoxiconazole exposure to soil microorganisms. Given the importance of the soil environment in agricultural production, characterization of the soil microbiome and metabolome can provide new insights into the ecological risks posed by exposure to the chiral triazole pesticide cis -epoxiconazole and its enantiomers. [Display omitted] • Cis -epoxiconazole showed stereoselective response in soil microbial community. • Cis -epoxiconazole showed stereoselective response in soil metabolic profile. • This study provided new insights for the microbiota stereoselective response. • The interdependence of soil metabolites and the microbiota was verified. [ABSTRACT FROM AUTHOR]

This study established an on-line SFE-SFC-MS/MS method for the determination of mefentrifluconazole (MFZ) enantiomers and pyraclostrobin (PY) in mango and mango juice. Key parameters of SFC separation and SFE extraction have been optimized for high efficiency, sensitivity, and environmental friendliness. Enthalpy controlled enantioseparations of MFZ were recognized by thermodynamic analysis. Molecular docking estimated the enantiomeric recognition of MFZ enantiomers binding to the chiral stationary phase. The mean recoveries (RSDs) were in the range of 94.5-106.8 % (4.2-15.4 %), 91.1-103 % (3.6-10.3 %), 94.7-102.7 % (3.8-9.8 %), and 93.2-106.9 % (4.1-12.1 %) for R-MFZ, S-MFZ, racemic MFZ, and PY under 3 spiked levels of interday assays (n = 15). The LOQs of R-MFZ, S-MFZ, and PY were 0.5, 0.5, and 1 μg kg -1 . The method was further applied to real samples in Guangxi Province, China with low acute and chronic dietary risk for MFZ and PY in mango and mango juice., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

An unprecedented electrochemical trifluoromethylation/SO 2  insertion/cyclization process has been achieved in an undivided cell in an atom-economic fashion. The protocol relies on tandem cyclization of N-cyanamide alkenes by using Langlois' reagent as a source of both CF 3 and SO 2 under direct anodically oxidative conditions, in which two C-C bonds, two C-X bonds (N-S and S-C), and two rings were formed in a single operation. This transformation enabled efficient construction of various trifluoromethylated cyclic N-sulfonylimines from readily accessible materials., (© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

In this work, a highly efficient pesticide residue screening and quantification method was established using ultrahigh-performance liquid chromatography-tandem quadrupole time-of-flight mass spectrometry based on in-source fragmentation. Over 400 pesticides were tested, among which 96 pesticides displayed in-source fragmentation. A novel concept of in-source fragment fraction was proposed to evaluate the extent of in-source fragmentation, which was found to be chemical structure- and source parameter-dependent. A high-resolution MS/MS library containing 403 pesticides and 126 fragments was created and was applied for library searching of pesticide residues in vegetables and fruits. The introduction of in-source fragments effectively circumvented misannotation and occurrence of false negatives. The quantification ability for the fragments was validated in terms of recovery, linearity, and limit of quantification and its superiority to the parent pesticides was established. Finally, the proposed method was applied for the analysis of real samples and proficiency test samples, and false negative results were successfully avoided in the analysis.

Field investigations on perfluoroalkyl acid (PFAA) levels in various environmental matrixes were reported, but there is still a lack of PFAA level data for agricultural environments, especially agricultural producing areas, so we collected soil, irrigation water and agricultural product samples from agricultural producing areas in the provinces of Liaoning, Shandong and Sichuan in China. The background pollution from instruments was removed and C₄-C 18 PFAAs were detected by LC-MS/MS. The concentrations of PFAAs in the top and deep layers of soil were compared, and the levels of PFAAs in different agricultural environments (greenhouses and open agriculture) were analyzed. We found the order of PFAA levels by province was Shandong > Liaoning > Sichuan. A descending trend of PFAA levels from top to deep soil and open to greenhouse agriculture was shown and perfluorobutanoic acid (PFBA) was considered as a marker for source analysis. Bean vegetables contribute highly to the overall PFAA load in vegetables. A significant correlation was shown between irrigation water and agricultural products. The EDI (estimated daily intake) from vegetables should be of concern in China., Competing Interests: The authors declare no conflict of interest.

Protein kinase A (PrkA), also known as AMP-activated protein kinase, functions as a serine/threonine protein kinase (STPK), has been shown to be involved in a variety of important biologic processes, including pathogenesis of many important diseases in mammals. However, the biological functions of PrkA are less known in prokaryote cells. Here, we explored the function of PrkA as well as its underlying molecular mechanisms using the model bacterium Bacillus subtilis168. When PrkA is inhibited by 9-β-D-arabinofuranosyladenine (ara-A) in the wild type strain or deleted in the ΔprkA mutant strain, we observed sporulation defects in B. subtilis 168, suggesting that PrkA functions as a sporulation-related protein. Transcriptional analysis using the lacZ reporter gene demonstrated that deletion of prkA significantly reduced the expression of the transcriptional factor σ(K) and its downstream genes. Complementation of sigK gene in prkA knockout mutant partially rescued the phenotype of ΔprkA, further supporting the hypothesis that the decreased σ(K) expression should be one of the reasons for the sporulation defect resulting from prkA disruption. Finally, our data confirmed that Hpr (ScoC) negatively controlled the expression of transcriptional factor σ(K), and thus PrkA accelerated sporulation and the expression of σ(K) by suppression of Hpr (ScoC). Taken together, our study discovered a novel function of the eukaryotic-like STPK PrkA in spore development as well as its underlying molecular mechanism in B. subtilis.

The enantioselective degradation behavior of fenoxaprop-ethyl (FE) and its chiral metabolite fenoxaprop (FA) in three soils under native conditions was investigated. Two pairs of enantiomers were analyzed by high-performance liquid chromatography (HPLC) with an amylose tri-(3,5-dimethylphenylcarbamate) (ADMPC) chiral column. The degradation of racemic FE in three soils showed the herbicidally inactive S-(-)-enantiomer degraded faster than the active R-(+)-enantiomer. FE was configurationally stable in soils because no interconversion to the respective antipodes was observed during incubation of the enantiopure S-(-)- or R-(+)-FE. The main metabolites of FE were confirmed as FA and 6-chloro-2,3-dihydrobenzoxazol-2-one (CDHB), and the formation of the chiral metabolite FA showed enantioselectivity in soils. The degradation of rac-FA was also enantioselective with the S-(-)-FA preferentially degraded: the half-life (t(1/2)) of the S-form in the three soils ranged from 2.03 to 5.17 days, and that of R-form ranged from 2.42 to 20.39 days. The inversion of the S-(-)-enantiomer into the R-(+)-enantiomer occurred in two of the three soils when the enantiopure S-(-)- and R-(+)-FA were incubated. The data from sterilized control experiments indicated that the enantioselectivity of FE and FA was attributed to microbially mediated processes.