A novel "Turn-Off-On" fluorescent probe for specific sequential detection of Cu2+ and glyphosate and its application in biological imaging.

As common pollutants, Cu2+ and glyphosate pose a serious threat to human health and the ecosystem. Herein, a fluorescent probe (E)-7-(diethylamino)-N'(4-(diethylamino)-2-hydroxybenzyl)-2-oxo-2H chromophore-3-carbazide (DDHC) was designed and synthesised for the sequential recognition of Cu2+ and glyphosate. DDHC has the advantages of a short synthesis path, easy-to-obtain raw materials, good anti-interference ability, and strong stability. The interaction of the DDHC-Cu2+ complexes with glyphosate allows the amino and carboxyl groups in glyphosate molecules to coordinate with Cu2+ strongly, competing for the Cu2+ in the DDHC-Cu2+ complexes and releasing the DDHC, leading to the recovery of fluorescence. The recognition was further validated through Job's plot, HRMS, and DFT calculations. In addition, the successful recovery of Cu2+ and glyphosate in different environmental water samples fully demonstrates the practical application potential of DDHC. Especially, DDHC has low cytotoxicity and can enter zebrafish and HeLa cells, rapidly reacting with Cu2+ and glyphosate in the body, generating visible fluorescence quenching and recovery phenomena, achieving real-time visual monitoring of exogenous Cu2+ and glyphosate in zebrafish and HeLa cells. The targeting and dual selectivity of DDHC greatly enhance its potential application value in the field of detection, providing important theoretical support for studying the fate of multiple pollutants in the environment.

Influence of para-substituted benzaldehyde derivatives with different push/pull electron strength groups on the conformation of human serum albumin and toxicological effects in zebrafish.

Excessive intake of benzaldehyde and its derivatives can cause irreversible damage to living organisms. Hence, benzaldehyde derivatives with different para-substitutions of push/pull electronic groups were chosen to investigate the effect of different substituent properties on the structure of human serum albumin (HSA). The binding constants, number of binding sites, major interaction forces, protein structural changes, and binding sites of benzaldehyde (BzH) and its derivatives (4-BzHD) with HSA in serum proteins were obtained based on multispectral and molecular docking techniques. The mechanism of BzH/4-BzHD interaction on HSA is mainly static quenching and is accompanied by the formation of a ground state complex. BzH/4-BzHD is bound to HSA in a 1:1 stoichiometric ratio. The interaction forces for the binding of BzH/4-BzHD to HSA are mainly hydrogen bonding and hydrophobic interaction, which are also accompanied by a small amount of electrostatic interactions. The effect of BzH/4-BzHD on HSA conformation follows: 4-Diethylaminobenzaldehyde (4-DBzH) > 4-Nitrobenzaldehyde (4-NBzH) > 4-Hydroxybenzaldehyde (4-HBzH) > 4-Acetaminobenzaldehyde (4-ABzH) > BzH, which means that the stronger push/pull electronic strength of the para-substituted benzaldehyde derivatives has a greater effect on HSA conformation. Furthermore, the concentration-lethality curves of different concentrations for BzH/4-BzHD on zebrafish verified above conclusion. This work provides a scientific basis for the risk assessment of benzaldehyde and its derivatives to the ecological environment and human health and for the environmental toxicological studies of benzaldehyde derivatives with different strengths of push/pull electron substitution.

Significantly enhanced biodegradation of profenofos by Cupriavidus nantongensis X1T mediated by walnut shell biochar.

The feasibility of using walnut shell biochar to mediate biodegradation of Cupriavidus nantongensis X1T for profenofos was investigated. The results of scanning electron microscopy, classical DLVO theory and Fourier transform infrared spectroscopy indicated that strain X1T was stably immobilized on biochar by pore filling, van der Waals attraction, and hydrogen bonding. Profenofos degradation experiments showed that strain X1T immobilized on biochar significantly decomposed profenofos (shortened the half-life by 5.2 folds) by promoting the expression of the degradation gene opdB and the proliferation of strain X1T. The immobilized X1T showed stronger degradation ability than the free X1T at higher initial concentration, lower temperature and pH. The immobilized X1T could maintain 83% of removal efficiency for profenofos after 6 reuse cycles in paddy water. Thus, X1T immobilized using walnut shell biochar as a carrier could be practically applied to biodegradation of organophosphorus pesticides present in agricultural water.

Complete biodegradation of fungicide carboxin and its metabolite aniline by Delftia sp. HFL-1.

Fungicide carboxin was commonly used in the form of seed coating for the prevention of smut, wheat rust and cotton damping-off, leading carboxin and its probable carcinogenic metabolite aniline to directly enter the soil with the seeds, causing residual pollution. In this study, a novel carboxin degrading strain, Delftia sp. HFL-1, was isolated. Strain HFL-1 could use carboxin as the carbon source for growth and completely degrade 50 mg/L carboxin and its metabolite aniline within 24 h. The optimal temperatures and pH for carboxin degrading by strain HFL-1 were 30 to 42 °C and 5 to 9, respectively. Furthermore, the complete mineralization pathway of carboxin by strain HFL-1 was revealed by High Resolution Mass Spectrometer (HRMS). Carboxin was firstly hydrolyzed into aniline and further metabolized into catechol through multiple oxidation processes, and finally converted into 4-hydroxy-2-oxopentanoate, a precursor of the tricarboxylic acid cycle. Genome sequencing revealed the corresponding degradation genes and cluster of carboxin. Among them, amidohydrolase and dioxygenase were key enzymes involved in the degradation of carboxin and aniline. The discovery of transposons indicated that the aniline degradation gene cluster in strain HFL-1 was obtained via horizontal transfer. Furthermore, the degradation genes were cloned and overexpressed. The in vitro test showed that the expressed degrading enzyme could efficiently degrade aniline. This study provides an efficient strain resource for the bioremediation of carboxin and aniline in contaminated soil, and further revealing the molecular mechanism of biodegradation of carboxin and aniline.

Chicken feedlot revisited: Co-dispersal of antibiotic and metal resistome under banning in-feed veterinary antibiotics.

Intensive livestock farming has been implicated as a notorious hotspot for antibiotic resistance genes (ARGs) due to the excessive or inappropriate use of in-feed antibiotics over the past few decades. Since China implemented a ban on the use of antibiotics in animal feed since 2020, the dissemination of ARGs in the vicinity of feedlots has remained unclear. This study presents a case study that aims to investigate the dispersal of antibiotics and ARGs from a chicken feedlot (established in 2020) to the adjacent aquatic and soil environments. Comparing the sample collected from upstream area, the water and sediment samples from midstream and downstream areas showed an increase in total antibiotic residues and metal content (Cu and Zn) by 4.2-5.3 fold and 1.3-22.6 fold, respectively. The downstream water samples exhibited a 2.49-2.93-fold increase in the abundance of ARGs and a 1.48-1.75-fold increase in the abundance of metal resistance genes (MRGs). The results of Pearson correlation and metagenome-assembled genome revealed a tendency for the co-occurrence of ARGs and MRGs. The dissemination of ARGs and MRGs is primarily driven by tetracycline, tylosin, Cu, and, Mn, with mobile genetic elements playing a more significant role than bacterial communities. These findings shed light on the overlooked co-dispersal pattern of ARGs and MRGs in the environment surrounding feedlots, particularly in the context of banning in-feed veterinary antibiotics.

Enantioselective effects of chiral prothioconazole and its metabolites: Oxidative stress in HepG2 cells and lysozyme activity.

Chiral pesticides may exhibit enantioselectivity in terms of bioconcentration, environmental fate, and reproductive toxicity. Here, chiral prothioconazole and its metabolites were selected to thoroughly investigate their enantioselective toxicity and mechanisms at the molecular and cellular levels. Multispectral techniques revealed that the interaction between chiral PTC/PTCD and lysozyme resulted in the formation of a complex, leading to a change in the conformation of lysozyme. Meanwhile, the effect of different conformations of PTC/PTCD on the conformation of lysozyme differed, and its metabolites were able to exert a greater effect on lysozyme compared to prothioconazole. Moreover, the S-configuration of PTCD interacted most strongly with lysozyme. This conclusion was further verified by DFT calculations and molecular docking as well. Furthermore, the oxidative stress indicators within HepG2 cells were also affected by chiral prothioconazole and its metabolites. Specifically, S-PTCD induced more substantial perturbation of the normal oxidative stress processes in HepG2 cells, and the magnitude of the perturbation varied significantly among different configurations (P > 0.05). Overall, chiral prothioconazole and its metabolites exhibit enantioselective effects on lysozyme conformation and oxidative stress processes in HepG2 cells. This work provides a scientific basis for a more comprehensive risk assessment of the environmental behaviors and effects caused by chiral pesticides, as well as for the screening of highly efficient and less biotoxic enantiomeric monomers.

Pyrrolizidine Alkaloids in Tea (Camellia sinensis L.) from Weeds through Weed-Soil-Tea Transfer and Risk Assessment of Tea Intake.

Pyrrolizidine alkaloids (PAs) have been detected in tea and can threaten human health. However, the specific source of PAs in tea is still unclear. Here, 88 dried tea products collected from six major tea-producing areas in Anhui Province, China, were analyzed. The detection frequency was 76%. The content of total PAs in dried tea was between 1.1 and 90.5 µg/kg, which was all below the MRL recommended by the European Union (150 µg/kg). In the Shexian tea garden, PAs in the weeds and weed rhizospheric soil around tea plants and the fresh tea leaves were analyzed. Intermedine (Im), intermedine-N-oxide (ImNO), and jacobine-N-oxide (JbNO) were transferred through the weed-to-soil-to-tea route into the fresh tea leaves; only Im and ImNO were detected in dried tea samples. Potential risk of the total PAs in the tea infusion was assessed according to the margin of exposure method, and it might be a low concern for public health.

Dual metabolic pathways co-determine the efficient aerobic biodegradation of phenol in Cupriavidus nantongensis X1.

Phenol, as an important chemical raw material, often exists in wastewater from chemical plants and pollutes soil and groundwater. Aerobic biodegradation is a promising method for remediation of phenolic wastewater. In this study, degradation characteristics and mechanisms of phenol in Cupriavidus nantongensis X1 were explored. Strain X1 could completely degrade 1.5 mM phenol within 32 h and use it as the sole carbon source for growth. The optimal degradation temperature and pH for phenol by strain X1 were 30 °C and 7.0. The detection of 3-oxoadipate and 4-hydroxy-2-oxopentanoate indicated that dual metabolic pathways coexist in strain X1 for phenol degradation, ortho- and meta-pathway. Genome and transcriptome sequencing revealed the whole gene clusters for phenol biomineralization, in which C12O and C23O were key enzymes in two metabolic pathways. The ribosome proteins were also involved in the regulation of phenol degradation. Meanwhile, the degradation activities of enzyme C23O was 188-fold higher than that of C12O in vitro, which indicated that the meta-pathway was more efficient than ortho-pathway for catechol degradation in strain X1. This study provides an efficient strain resource for phenol degradation, and the discovery of dual metabolic pathways provides new insight into the aerobic biological metabolism and bioremediation of phenol.

Metabolic responses of tea (Camellia sinensis L.) to the insecticide thiamethoxam.

BACKGROUND: Thiamethoxam (TMX) is insecticidal, but also can trigger physiological and metabolic reactions of plant cycles. The objective of this work was to evaluate the physiological and metabolic effect of TMX on tea plants and its potential benefits. RESULTS: In this study, dose of TMX (0.09, 0.135 and 0.18 kg a.i./ha) were tested. Except for peroxidase (POD) and glutathione S-transferase (GST), chlorophyll, carotenoid, catalase (CAT) and malondialdehyde (MDA) were significantly affected compared with the controls. The CAT activity was increased by 3.38, 1.71, 2.91 times, respectively, under three doses of TMX treatment. The metabolic response between TMX treatment and control groups on the third day was compared using a widely targeted metabolomics. A total of 97 different metabolites were identified, including benzenoids, flavonoids, lipids and lipid-like molecules, organic acids and derivatives, organic nitrogen compounds, organic oxygen compounds, organoheterocyclic compounds, phenylpropanoids and polyketides, and others. Those metabolites were mapped on the perturbed metabolic pathways. The results demonstrated that the most perturbation occurred in flavone and flavonol biosynthesis. The beneficial secondary metabolites luteolin and kaempferol were upregulated 1.46 and 1.31 times respectively, which protect plants from biotic and abiotic stresses. Molecular docking models suggest interactions between TMX and flavonoid 3-O-glucosyltransferase. CONCLUSION: Thiamethoxam spray positively promoted the physiological and metabolic response of tea plants. And this work also provided the useful information of TMX metabolism in tea plants as well as rational application of insecticides. © 2023 Society of Chemical Industry.

Enantioselective effect of chiral prothioconazole on the conformation of bovine serum albumin.

As a typical chiral triazole fungicide, the enantioselective toxicity of prothioconazole to environmental organisms is of increasing concern. Herein, the binding mechanism of chiral PTCs to BSA was investigated by multi-spectral technique and molecular docking. Fluorescence titration and fluorescence lifetime experiments fully established that quenching BSA fluorescence by chiral PTCs is static quenching and could spontaneously bind to BSA. Hydrophobic interactions dominate the binding process of chiral PTCs to BSA. Differently, although both chiral PTCs and BSA have a primary binding site, the difference in chiral isomerism leads to a stronger binding ability of S-PTC than R-PTC. Both configurations of PTC can change the conformation of BSA and induce changes in the microenvironment around its amino acid residues, and the effect of S-PTC is more significant. Overall, S-PTC exhibited a more substantial effect on BSA structure relative to R-PTC. That is, S-PTC may lead to more potent potential toxicological effects on environmental organisms. This study provides a comprehensive assessment of the environmental behavior of chiral pesticides and their potential toxicity to environmental organisms at the molecular level and provides a theoretical basis for the screening of highly effective and biologically less toxic enantiomers of chiral pesticides.

Efficient Knocking Out of the Organophosphorus Insecticides Degradation Gene opdB in Cupriavidus nantongensis X1T via CRISPR/Cas9 with Red System.

Cupriavidus nantongensis X1T is a type strain of the genus Cupriavidus, that can degrade eight kinds of organophosphorus insecticides (OPs). Conventional genetic manipulations in Cupriavidus species are time-consuming, difficult, and hard to control. The clustered regularly interspaced short palindromic repeat (CRISPR)/associated protein 9 (Cas9) system has emerged as a powerful tool for genome editing applied in prokaryotes and eukaryotes due to its simplicity, efficiency, and accuracy. Here, we combined CRISPR/Cas9 with the Red system to perform seamless genetic manipulation in the X1T strain. Two plasmids, pACasN and pDCRH were constructed. The pACasN plasmid contained Cas9 nuclease and Red recombinase, and the pDCRH plasmid contained the dual single-guide RNA (sgRNA) of organophosphorus hydrolase (OpdB) in the X1T strain. For gene editing, two plasmids were transferred to the X1T strain and a mutant strain in which genetic recombination had taken place, resulting in the targeted deletion of opdB. The incidence of homologous recombination was over 30%. Biodegradation experiments suggested that the opdB gene was responsible for the catabolism of organophosphorus insecticides. This study was the first to use the CRISPR/Cas9 system for gene targeting in the genus Cupriavidus, and it furthered our understanding of the process of degradation of organophosphorus insecticides in the X1T strain.

A reversible CHEF-based NIR fluorescent probe for sensing Hg2+ and its multiple application in environmental media and biological systems.

Hg2+ poses a great threat to human health and the environment due to its bioaccumulation and permanent damage. Herein, a reversible CHEF-based near-infrared fluorescent probe 2-(3-((E)-4-((E)-4-(diethylamino)-2- hydroxybenzylidene)amino)styryl)-5,5-dimethylcyclohex-2-en-1-ylidene)propanedinitrile (DHEY) capable of specifically recognizing Hg2+ was constructed. DHEY exhibits advantages of large Stokes shift (157 nm), excellent selectivity, high sensitivity (LOD = 3.2 µg/L), and fast response efficiency (<3 min). Interestingly, DHEY can also realize rapid and effective detection of Hg2+ after being recycled 7 times. The successful recovery of trace Hg2+ in different environmental water samples fully demonstrates the potential of DHEY for actual applications. In particular, DHEY enables real-time observation of the distribution and translocation pattern of exogenous Hg2+ in HeLa cells and zebrafish. This work provides important theoretical support for investigating the fate of heavy metal ions in the environment using fluorescence techniques.

Efficient biodegradation characteristics and detoxification pathway of organophosphorus insecticide profenofos via Cupriavidus nantongensis X1T and enzyme OpdB.

Profenofos residues in the environment pose a high risk to mammals and non-target organisms. In this study, the biodegradation and detoxification of profenofos in an efficient degrading strain, Cupriavidus nantongensis X1T, was investigated. Strain X1T could degrade 88.82 % of 20 mg/L profenofos in 48 h. The optimum temperature and inoculation amount of strain X1T for the degradation of profenofos were 30-37 °C and 20 % (V/V), respectively. Metabolic pathway analysis showed that strain X1T could degrade both profenofos and its main metabolite 4-bromo-2-chlorophenol. Metabolite toxicity analysis results showed that dehalogenation was the main detoxification step in profenofos biodegradation. The key gene and enzyme for profenofos degradation in strain X1T were also explored. RT-qPCR shows that organophosphorus hydrolase (OpdB) was the key enzyme to control the hydrolysis process in strain X1T. The purified enzyme OpdB in vitro had the same degradation characteristics as strain X1T. Divalent metal cations could significantly enhance the hydrolysis activity of strain X1T and enzyme OpdB. Meanwhile, strain X1T could degrade 60.89 % of 20 mg/L profenofos in actual field soil within 72 h. This study provides an efficient biological resource for the remediation of profenofos residual pollution in the environment.

Development of a polyurethane-coated thin film solid phase microextraction device for multi-residue monitoring of pesticides in fruit and tea beverages.

A novel solid-phase microextraction device coated with an efficient and cheap thin film of polyurethane was developed for trace determination of 13 widely used pesticides in fruit and tea beverages. A round-shaped polyurethane film covering the bottom of a glass vial was fabricated as the sorbent to exhibit a superior capacity for preconcentrating target compounds and reducing matrix interferences. After optimization of the key parameters including the film type, extraction time, solution pH, ionic strength, desorption solvent, and conditions, this device allowed an efficient adsorption-desorption cycle for the pesticides accomplished in one vial. Coupled with gas chromatography-electron capture detection, the polyurethane-coated thin film microextraction method was successfully established and applied for the analysis of real fruit and tea drinks, showing low limits of detection (0.001-0.015 µg/L), wide linear ranges (1.0-500.0 µg/L, r2  > 0.9931), good relative recoveries (77.2%-106.3%) and negligible matrix effects (86.1%-107.5%) for the target pesticides. The proposed approach revealed strong potential of extending its application by flexibly modifying the type or size of the coating film. This study provides insights into the enrichment of contaminants from complex samples using inexpensive and reusable microextraction devices that can limit the environmental and health impact of the sample preparation protocol.

Pyrrolizidine-producing weeds in tea gardens as an indicator of alkaloids in tea.

Pyrrolizidine alkaloids (PAs) can be transferred between plants via soil. Indicators of PAs in tea products are useful for tea garden management. In the present work a total of 37 weed species, 37 weed rhizospheric soils and 24 fresh tea leaf samples were collected from tea gardens, in which PAs were detected in 35 weeds species, 21 soil samples and 10 fresh tea leaves samples. In Shexian tea garden, 12.9 µg/kg of intermedine (Im) in one bud plus three leaves, 1.40 and 14.6 µg/kg of intermedine-N-oxide (ImNO) in one bud plus two leaves and one bud plus three leaves were detected, which were transferred from the PA-producing weeds via soil. However, no PAs were detected in fresh tea leaves collected from Langxi tea garden. The results indicated that synthesis of PAs in weeds and their transfer through the weed-soil-fresh tea leaf route varied with soil environments in different tea gardens.

Source and Route of Pyrrolizidine Alkaloid Contamination in Tea Samples.

Toxic pyrrolizidine alkaloids (PAs) are found in tea samples, which pose a threat to human health. However, the source and route of PA contamination in tea samples have remained unclear. In this work, an adsorbent method combined with UPLC-MS/MS was developed to determine 15 PAs in the weed Ageratum conyzoides L., A. conyzoides rhizospheric soil, fresh tea leaves, and dried tea samples. The average recoveries ranged from 78%-111%, with relative standard deviations of 0.33%-14.8%. Fifteen pairs of A. conyzoides and A. conyzoides rhizospheric soil samples and 60 fresh tea leaf samples were collected from the Jinzhai tea garden in Anhui Province, China, and analyzed for the 15 PAs. Not all 15 PAs were detected in fresh tea leaves, except for intermedine-N-oxide (ImNO) and senecionine (Sn). The content of ImNO (34.7 µg/kg) was greater than that of Sn (9.69 µg/kg). In addition, both ImNO and Sn were concentrated in the young leaves of the tea plant, while their content was lower in the old leaves. The results indicated that the PAs in tea were transferred through the path of PA-producing weeds-soil-fresh tea leaves in tea gardens.

Contrasting dynamics of manure-borne antibiotic resistance genes in different soils.

Antibiotic resistance genes (ARGs) are important biological contamination factors in soil systems, posing direct or indirect threats to soil health, food safety and human health. The ubiquitous pollution of ARGs is usually implicated with the application of organic manures in agricultural soil ecosystem. However, little is known about the transmission and fate of ARGs after manure input concerning different soils. Herein, the transmission potential and temporal dynamics of manure-associated ARGs was characterized with three different agricultural soils collected from Jiangxi (JX), Zhejiang (ZJ), and Jilin (JL), respectively. The results show that manure input did not affect the total abundance of ARGs in the receiving soils, but remarkedly alter the compositions of ARGs in soils. The manure-associated ARGs were significantly enriched in the manure-amended soils, including genes conferring resistance to sulfonamide, aminoglycoside, tetracycline, chloramphenicol, and trimethoprim with the fold of 1.97 - 27.86. Variance partitioning analysis showed that the major variances of ARG community was explained by mobile genetic elements and bacterial profile (> 76%) but not the concentrations of heavy metals and antibiotics. Furthermore, 31, 37, and 38 ARG subtypes were identified as the potential extrinsic ARGs derived from manures in the JX, ZJ, and JL soils, respectively, including 13 shared ARG subtypes. It was also found that the manure-associated ARGs (aadA, sul1, sul2, tetC, and tetG) declined with the incubation time in the JX and ZJ soils, whereas they firstly decreased and then increased in the JL soil. The abundance of these five ARGs in the JL soil was significantly higher than that in the JX and ZJ soils. Collectively, this finding revealed that soil type was responsible for the transmission and fate of manure-associated ARGs in agroecosystem.

Construction of a novel fluorescent nanocarrier with double hollow shells for pH-controlled release of imidacloprid and its distribution and transport in bok choy.

Nanotechnology has been widely used in the field of pesticides. Integration of nano-pesticides and carbon dot fluorescence can fully utilize the potential for high admission of pesticides on leaves and convenience observation of its distribution and transport in the tissues. In the present study, a fluorescent mesoporous nanosilica with double hollow shells for loading imidacloprid (Im@FL-MSNs) was designed and synthesized. The physical and chemical properties of the imidacloprid nanocarriers were characterized by transmission electron microscopy (TEM), FT-IR spectroscopy, thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and N2 adsorption/desorption. When the mass ratio of FL MSNs to imidacloprid is 6:5, Im@FL-MSNs exhibits good fluorescence properties, high loading efficiency (∼30%), great slow-release performance as well as pH controllability. Besides, Im@FL-MSNs can improve the ability of imidacloprid to adhere on the leaf surface of bok choy (Initial contact angled is greater than 80°ï¼‰. Importantly, Im@FL-MSNs did not reduce the biological activity of imidacloprid (LC50 (95% CI) = 1.43 mg/L). It was able to visually study the absorption and distribution of imidacloprid in bok choy plants, and provide theoretical and technical guidance for pesticide reduction.

Efficient Total Synthesis and Herbicidal Activity of 3-Acyltetramic Acids: Endogenous Abscisic Acid Synthesis Regulators.

An efficient synthesis method will allow a large number of tetramic acid analogues to be synthesized for property and potency optimization. In this study, a facile and efficient method was described for the synthesis of 3-acyltetramic acids. The synthesis was accomplished mainly via (1) mild intramolecular cyclization and (2) the formation of ß-ketoamides between nucleophiles and acyl Meldrum's acids. 3-Acyltetramic acid exhibited phytotoxicity against Echinochloa crusgalli and Portulaca oleracea. At a dosage of 750 g ha-1, 6k and 6a showed high herbicidal activity against E. crusgalli, Digitaria sanguinalis and P. oleracea, Amaranthus retroflexus, respectively. 6k inhibited the synthesis of endogenous abscisic acid, thus seedling germination and plant growth. The incorporation of various acyl Meldrum's acids and amino acid esters was applicable to the parallel synthesis of 3-acyltetramic acids. The mode of action and herbicidal activity indicate that 3-tetramic acid had good herbicidal performance and was a promising herbicide candidate. This study will provide a reference for novel herbicide development.

Cyanidin-3-O-glucoside mediated photodegradation of profenofos in water.

Flavonoids can sensitize and quench the photolysis of pesticides such as profenofos in surface water. Profenofos has been frequently detected in surface and underground water. The present study investigated the photolysis of profenofos under various conditions, including natural and artificial light illumination, with and without cyanidin-3-O-glucoside (Cy3G) and in pure and surface water. The degradation half-lives of profenofos in distilled water with 10 equivalents Cy3G of profenofos were 21.7 min, 9.5 h, 12.5 h and 180 h under high-pressure mercury light, UV, Xenon lamp and solar irradiation, respectively, while those without Cy3G were 8.1 min, 6.1 h, 8.2 h and 89.9 h, respectively. The photolysis rate of profenofos under sunlight and artificial light was reduced by 1.5-2.7 times due to Cy3G, compared to the Cy3G-free control. Under sunlight irradiation, the effects of Cy3G on profenofos photolysis were larger than those under high-pressure mercury lamp irradiation. Cy3G also significantly reduced the photolysis rate of profenofos under different pH conditions and in natural water. In addition, Cy3G exhibited a significant capacity of scavenging hydroxyl radicals and quenching 1O2 in water. The effect of Cy3G on profenofos photolysis was demonstrated through their interrelations in the natural environment. These findings can help understanding of the effect of flavonoids on profenofos photolysis and are of significance for predicting the degradation kinetics of profenofos and accurately assessing its potential biological impacts.