Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 46
Filter
1.
Ecotoxicol Environ Saf ; 257: 114908, 2023 Jun 01.
Article in English | MEDLINE | ID: mdl-37080128

ABSTRACT

N-doped biochar is widely used for activating persulfate to degrade organic pollutants. Which type of N atom is the key factor for activation is still unclear and needs to be further explored and analyzed. In this study, four kinds of biochar were prepared using urea and rice husk as precursors, and tested for the catalytic degradation of dimethomorph. Increasing the nitrogen doping level caused the catalytic removal efficiency of dimethomorph in the presence of peroxymonosulfate increased from 16.6% to 86.8%. A correlation analysis showed that the ability of N-doped biochar to activate PMS is mainly related to the content of pyrrole N, graphite N and carbonyl and the degree of defects. In experiments on electron paramagnetic resonance and free radical suppression, the reactive species of SO4•-, 1O2,·OH and O2.- were detected, among which 1O2 was found to be the main agent in the nonradical pathway. The degradation pathways for dimethomorph were analyzed based on a total of 8 degradation products identified by high-performance liquid chromatography-time of flight mass spectrometry (HPLC-Q-TOFMS). The results of this study provide a fundamental basis for using agricultural waste to produce inexpensive and efficient nonmetal catalysts that are highly effective in reducing dimethomorph levels in agricultural lands.


Subject(s)
Oryza , Nitrogen/chemistry , Charcoal , Peroxides/chemistry
2.
Molecules ; 28(9)2023 Apr 27.
Article in English | MEDLINE | ID: mdl-37175171

ABSTRACT

Although dicofol has been widely banned all over the world as a kind of organochlorine contaminant, it still exists in the environment. This study developed a high-performance liquid chromatography coupled with mass spectrometry (HPLC-MS/MS) detection technique for dicofol, an environmental pollutant, for the first time using in-source fragmentation. The results confirmed that m/z 251 was the only precursor ion of dicofol after in-source fragmentation, and m/z 139 and m/z 111 were reasonable product ions. The main factors triggering the in-source fragmentation were the H+ content and solution conductivity when dicofol entered the mass spectrometer. Density functional theory can be used to analyze and interpret the mechanism of dicofol fragmentation reaction in ESI source. Dicofol reduced the molecular energy from 8.8 ± 0.05 kcal/mol to 1.0 ± 0.05 kcal/mol, indicating that the internal energy release from high to low was the key driving force of in-source fragmentation. A method based on HPLC-MS/MS was developed to analyze dicofol residues in environmental water. The LOQ was 0.1 µg/L, which was better than the previous GC or GC-MS methods. This study not only proposed an HPLC-MS/MS analysis method for dicofol for the first time but also explained the in-source fragmentation mechanism of compounds in ESI source, which has positive significance for the study of compounds with unconventional mass spectrometry behavior in the field of organic pollutant analysis and metabonomics.

3.
Ecotoxicol Environ Saf ; 238: 113596, 2022 Jun 15.
Article in English | MEDLINE | ID: mdl-35526453

ABSTRACT

Quizalofop-P-ethyl (QpE), a highly efficient selective herbicide, has good control effect on annual and perennial weeds. However, its excessive use will pose a threat to the ecological environment. QpE has been proven harmful to aquatic organisms, but there is little evidence on the adverse effects of QpE in the early life of aquatic organisms. In this work, zebrafish (Danio rerio) embryos were treated with 0.10, 0.20, 0.30, 0.40, and 0.50 mg/L of QpE for 120 h. The findings revealed that the LC50 value of QpE to zebrafish embryos was 0.23 mg/L at 96 hpf. QpE exposure significantly increased the mortality rate, decreased the hatching rate and caused morphological defects during zebrafish embryonic development, with a concentration dependent manner. QpE also caused severe morphological changes in the cardiovascular system, as well as resulted in a dysfunction in cardiovascular performance. Meanwhile, both histopathological examination and neutrophil observations showed inflammatory response occurred in the heart. Furthermore, several genes associated with heart development and inflammation were significantly altered following QpE exposure. A protein-protein interaction (PPI) network analysis proved that there was a connection between the changed heart development-relevant and inflammation-related genes. Taken together, our findings suggest that QpE causes cardiotoxicity in zebrafish embryos by altering the expression of genes in the regulatory network of cardiac development, which might be aggravated by inflammatory reactions, thereby affecting embryo development. These findings generated here are useful for in-depth assessment of the effects of QpE on early development of aquatic organisms and providing theoretical foundation for risk management measures.


Subject(s)
Water Pollutants, Chemical , Zebrafish , Animals , Aquatic Organisms , Cardiotoxicity/metabolism , Embryo, Nonmammalian , Inflammation/metabolism , Propionates , Quinoxalines , Water Pollutants, Chemical/metabolism
4.
J Org Chem ; 84(17): 10757-10763, 2019 09 06.
Article in English | MEDLINE | ID: mdl-31337212

ABSTRACT

A new dimeric eudesmane sesquiterpenoid with an unreported 6/6/5/6/6 fused carbon skeleton, echingridimer A (1), and five monomers (2-6), including two new compounds (2 and 3), were isolated from the roots of Echinops grijsii. Their structures and absolute configurations were elucidated by comprehensive spectroscopic analyses and confirmed by X-ray crystallography or electronic circular dichroism spectra. Compound 1 represents the first example of a 3,15'-linked Michael-type adduct of two eudesmanes, which feature a unique 1-oxaspiro[4.5]decan moiety. The plausible biogenetic pathway for 1-6 was briefly discussed. The oxaspiro dimer (1) not only showed stronger aphicidal activity than closely related monomeric compounds (2-6) and the commercial aphicide pymetrozine but also exhibited remarkable insecticide activity against a broad range of aphids, thus could be used as a potential biobased insecticide to suppress aphids.


Subject(s)
Aphids , Asteraceae/chemistry , Dimerization , Insecticides/chemistry , Sesquiterpenes/chemistry , Animals , Models, Molecular , Molecular Conformation
5.
Arch Virol ; 164(2): 579-584, 2019 Feb.
Article in English | MEDLINE | ID: mdl-30417198

ABSTRACT

Ferret badger (FB, Melogale moschata) rabies is an increasing public health threat to humans, with FBs being a major reservoir and vector of rabies in China. Based on 152 published nucleotide sequences of the FB rabies virus (RABV) nucleoprotein, phylogenetic analysis revealed them to be clustered into six FB-related lineages, FB-I to FB-VI. The genetic features of members of lineage FB-VI suggest that cross-species transmission occurs between FBs and dogs. Here, we describe the phylogenetic relationships between FB-RABVs, their geographic segregation, and their evolutionary dynamics in epizootic regions.


Subject(s)
Dog Diseases/virology , Ferrets/virology , Rabies virus/isolation & purification , Rabies/veterinary , Rabies/virology , Animals , China , Dog Diseases/transmission , Dogs , Humans , Phylogeny , Rabies virus/classification , Rabies virus/genetics , Rabies virus/physiology , Taiwan
7.
Pestic Biochem Physiol ; 140: 97-104, 2017 Aug.
Article in English | MEDLINE | ID: mdl-28755702

ABSTRACT

Camptothecin (CPT), a natural alkaloid extracted from Camptotheca acuminata Decne, exhibits potential insecticidal activities against various insect species. Our previous studies have showed that CPTs induced apoptosis in Spodoptera exigua Hübner cell line which is mediated preliminarily by the mitochondrial pathway. In this study, changes of mitochondrial morphologic and function were investigated to characterize mitochondrial responses in CPTs induced apoptosis. After incubation IOZCAS-Spex-II cells with CPT and HCPT, mitochondria exhibited obvious changes in the size, morphology and distribution, and ultrastructural alterations characterized by disruption of cristae and membrane. The typical characteristics of apoptosis, including chromatin condensation, nucleus shrivels, and cytoplasmic vacuoles were found. CPT and HCPT induced IOZCAS-Spex-II cell apoptosis accompanied with increased dramatically cytosolic Ca2+ and reduced mitochondrial membrane potential in the dose and time-dependent pattern. Cytochrome c release induced by CPT and HCPT was partially reduced in the presence of CsA, which suggested that the opening of mitochondrial permeability transition pore. Taken together, these results suggested the role of mitochondria in regulation of insect cell apoptosis, which provided the basic information for illustrating the apoptosis pathway in insects and for using reasonably CPTs to control insect pests.


Subject(s)
Apoptosis/drug effects , Camptothecin/analogs & derivatives , Camptothecin/pharmacology , Mitochondria/drug effects , Spodoptera/cytology , Animals , Biological Control Agents/pharmacology , Calcium/metabolism , Cell Line , Fat Body/cytology , Membrane Potential, Mitochondrial/drug effects , Mitochondria/ultrastructure
8.
Pestic Biochem Physiol ; 139: 46-52, 2017 Jun.
Article in English | MEDLINE | ID: mdl-28595921

ABSTRACT

Camptothecin (CPT), a quinolone alkaloid extracted from Camptotheca acuminata Decne, exhibits potential insecticidal activities against various insect species. Our previous studies have showed that CPT induced apoptosis in Spodoptera exigua Hübner cell line and inhibited the relaxation activity of topoisomerase I (Topo I). In this study, total seven 20(S)-t-butoxy carbonyl-amino acid derivatives of CPT were synthesized and evaluated for insecticidal activities, cytotoxicity and Topo I inhibitory activities. Results showed that introduction of t-Boc amino acids to 20-position on CPT improves contact assay and cytotoxicity of most derivatives toward S. exigua but reduces inhibitory effect on relaxation activity of S. exigua Topo I. Furthermore, compounds 1d and 1g demonstrated higher level of contact activities and cytotoxicity than CPT and hydroxyl-camptothecin (HCPT), which are potential to be developed as potential insecticides targeted at more than Topo I.


Subject(s)
Camptothecin/chemistry , Camptothecin/pharmacology , DNA Topoisomerases, Type I/metabolism , Insecticides/chemistry , Insecticides/pharmacology , Amino Acids/chemistry , Animals , Enzyme Activation/drug effects , Spodoptera/drug effects , Structure-Activity Relationship
9.
Heliyon ; 10(7): e29181, 2024 Apr 15.
Article in English | MEDLINE | ID: mdl-38601658

ABSTRACT

This study facilitates university student profiling by constructing a prediction model to forecast the classification of future students participating in a survey, thereby enhancing the utility and effectiveness of the questionnaire approach. In the context of the ongoing digital transformation of campuses, higher education institutions are increasingly prioritizing student educational development. This shift aligns with the maturation of big data technology, prompting scholars to focus on profiling university student education. While earlier research in this area, particularly foreign studies, focus on extracting data from specific learning contexts and often relied on single data sources, our study addresses these limitations. We employ a comprehensive approach, incorporating questionnaire surveys to capture a diverse array of student data. Considering various university student attributes, we create a holistic profile of the student population. Furthermore, we use clustering techniques to develop a categorical prediction model. In our clustering analysis, we employ the K-means algorithm to group student survey data. The results reveal four distinct student profiles: Diligent Learners, Earnest Individuals, Discerning Achievers, and Moral Advocates. These profiles are subsequently used to label student groups. For the classification task, we leverage these labels to establish a prediction model based on the Back Propagation neural network, with the goal of assigning students to their respective groups. Through meticulous model optimization, an impressive classification accuracy of 90.22% is achieved. Our research offers a novel perspective and serves as a valuable methodological reference for university student profiling.

10.
Chemosphere ; 350: 141027, 2024 Feb.
Article in English | MEDLINE | ID: mdl-38142880

ABSTRACT

Given the serious threat of acetochlor (ACT) to the aquatic ecological environment, designing wastewater treatment-oriented adsorbents for the sustainable remediation of actual ACT-contaminated water is a promising yet challenging strategy. Herein, a novel P-doped biochar (PBC-800) with a high adsorption capacity (51.34 mg g-1) and a rapid reaction rate (47.35 mg g-1 h-1) for ACT was prepared through pyrolyzing of rice straw biomass pre-impregnated with potassium dihydrogen phosphate (KH2PO4). Additionally, P-doped biochars synthesized at different pyrolysis temperatures exhibited significant variations in ACT adsorption performance, which was mainly ascribed to the distinction between hydrophilicity and sp2 conjugate C (ID/IG = 0.84-1.08). The adsorption behavior of ACT on PBC-800 followed the Elovich kinetics and Freundlich adsorption isotherm models. Thermodynamic calculations indicated that the adsorption of ACT by PBC-800 was a spontaneously disordered decreasing exothermic process. Besides, PBC-800 exhibited a powerful anti-interference for ACT adsorption within complex water matrices, highlighting its potential for various of practical applications. Through characterization analysis and further experiments, it was proved that the excellent adsorption performance of PBC-800 on ACT was ascribed to a combination of physical and chemical adsorption mechanisms, including 57.5% pore filling, 23.4% hydrophobic interaction, 12.7% π-π interaction, and 6.4% hydrogen bonding. Moreover, PBC-800 exerted a prominent adhesion impact upon Gram-positive and negative bacteria at 3 h. This study offers a new idea for the utilization of agricultural residues and provides insights into the mechanism of ACT adsorption through its derived biochar.


Subject(s)
Charcoal , Toluidines , Water Pollutants, Chemical , Adsorption , Charcoal/chemistry , Water , Water Pollutants, Chemical/chemistry , Kinetics
11.
Pestic Biochem Physiol ; 107(1): 18-24, 2013 Sep.
Article in English | MEDLINE | ID: mdl-25149230

ABSTRACT

Brucea javanica (L.) Merr. is a medicine plant distributed widely throughout Asia where its bitter fruits have been used traditionally in medicine for treating various ailments and controlling some pests. In recent years, concerns over the potential impact of synthetic pesticides on human health and environment have now become more pressing to develop environmentally friendly pesticides. In this paper, brusatol, a quassinoid, was isolated from the fruit of B. javanica, and identified using X-ray crystallographic analysis. Results showed that brusatol has potent contact toxicity (LD50, 2.91 µg/larva, 72 h) and anfieedant activity (AFC50, 17.4 mg/L, 48 h) against the third-instar larvae of Spodoptera exigua. Brusatol demonstrated cytotoxic effects to the tested insect cell lines, IOZCAS-Spex-II and Sf21, in a time- and dose-dependent manner. After brusatol treatment, apoptotic cell death with the DNA fragmentation, activation of caspase-3 and release of cytochrome c was preliminarily observed in both IOZCAS-Spex-II and Sf21. These results indicated the existence of apoptotic death with the mitochondrial-dependent pathway induced by brusatol in Sf21 and IOZCAS-Spex-II cell lines. Our studies will provide important knowledge to understand mechanisms of action of brusatol and to develop brusatol and its derivatives as insecticides.


Subject(s)
Brucea , Insecticides/pharmacology , Quassins/pharmacology , Animals , Apoptosis/drug effects , Caspase 3/metabolism , Cell Line , Cell Proliferation/drug effects , Cell Survival/drug effects , Cytochromes c/metabolism , DNA Fragmentation , Feeding Behavior/drug effects , Fruit , Insecta , Insecticides/chemistry , Insecticides/isolation & purification , Insecticides/toxicity , Larva/drug effects , Larva/physiology , Molecular Structure , Quassins/chemistry , Quassins/isolation & purification , Quassins/toxicity , Seeds/chemistry
12.
Article in English | MEDLINE | ID: mdl-37314913

ABSTRACT

Owing to its simplicity, the traditional k -means (Lloyd heuristic) clustering method plays a vital role in a variety of machine-learning applications. Disappointingly, the Lloyd heuristic is prone to local minima. In this article, we propose k -mRSR, which converts the sum-of-squared error (SSE) (Lloyd) into a combinatorial optimization problem and incorporates a relaxed trace maximization term and an improved spectral rotation term. The main advantage of k -mRSR is that it only needs to solve the membership matrix instead of computing the cluster centers in each iteration. Furthermore, we present a nonredundant coordinate descent method that brings the discrete solution infinitely close to the scaled partition matrix. Two novel findings from the experiments are that k -mRSR can further decrease (increase) the objective function values of the k -means obtained by Lloyd (CD), while Lloyd (CD) cannot decrease (increase) the objective function obtained by k -mRSR. In addition, the results of extensive experiments on 15 datasets indicate that k -mRSR outperforms both Lloyd and CD in terms of the objective function value and outperforms other state-of-the-art methods in terms of clustering performance.

13.
Sci Total Environ ; 870: 161541, 2023 Apr 20.
Article in English | MEDLINE | ID: mdl-36731560

ABSTRACT

Imidacloprid, a widely used neonicotinoid insecticide, poses a significant threat to aquatic ecosystems. Behavior is a functional indicator of the net sensory, motor, and integrative processes of the nervous system and is presumed to be more sensitive in detecting toxicity. In the present study, we investigated the behavioral effects of imidacloprid at the level of environmental concentrations (1, 10 and 100 µg/L) for a constant exposure to zebrafish adults, and performed the integrated transcriptomic and metabolomic analysis to analyze the molecular mechanism underlying behavioral effects of imidacloprid. Our results show that imidacloprid exposure significantly induce behavioral disruptions characterized by anxiety, depression, and reduced physiological function including exploratory, decision, social interaction and locomotor activity. Integrated transcriptomic and metabolomic analysis indicate that the disruption of circadian rhythm, metabolic imbalance of arginine and proline, and neurotransmitter disorder are the underlying molecular mechanisms of behavioral impairment induced by imidacloprid. The "gene-metabolite-disease" network consisted by 11 metabolites and 15 genes is associated human disease Alzheimer's disease (AD) and schizophrenia. Our results confirm the behavioral impairment induced by imidacloprid at environmental concentrations for constant exposure. The identified genes and metabolites can be used not only to illustrate the underlying mechanisms, but also can be developed as biomarkers in determining the ecological risk of imidacloprid to aquatic organisms even Homo sapiens.


Subject(s)
Water Pollutants, Chemical , Zebrafish , Animals , Humans , Zebrafish/metabolism , Transcriptome , Ecosystem , Neonicotinoids/toxicity , Neonicotinoids/metabolism , Water Pollutants, Chemical/toxicity , Water Pollutants, Chemical/metabolism
14.
Sci Total Environ ; 870: 161795, 2023 Apr 20.
Article in English | MEDLINE | ID: mdl-36708821

ABSTRACT

Microplastics (MPs) and pesticides frequently coexist in farmland soil; however, there are relatively few studies on the ecological risk assessment of soil animals attributed to the combined pollution caused by MPs and pesticides. Moreover, the influence of particle size on the combined toxic effects of MPs and pesticides remains poorly understood. In this study, different-sized polyethylene MPs (PE MPs; 10 µm, 500 µm, and 2 mm) were combined with a series of imidacloprid concentrations (IMI; 0.10, 0.50 and 1.00 mg/kg), and earthworms (Eisenia fetida) were exposed to these MP and IMI combinations for 28 d to explore the combined toxic effects and mechanisms. The results showed, compared with IMI or PE MPs exposure alone, the combined exposure of IMI and PE MPs did not substantially increase the acute toxicity of earthworms but significantly inhibited weight increase and induced more serious epidermal damage to earthworms with a size effect; among these 10 µm PE MPs combined with IMI exhibited the strongest toxic effects. In addition, the combined exposure decreased antioxidant enzymes activity and caused oxidative damage in earthworms. Transcriptome results demonstrated most of the treatment combinations affected the ferroptosis pathway, which was further verified by the increase in the total iron content, reactive oxygen species, and malondialdehyde content in earthworms. Combined with the analysis of key signalling pathways, the above results revealed that the combined exposure to IMI and PE MPs showed stronger toxicity to earthworms than exposure to either IMI or MPs alone, which was mediated by the superimposed effect of ferroptosis and oxidative damage. Moreover, the effect was size-dependent, with 10 µm PE MPs combined with IMI exhibiting the strongest toxic effects. This study aimed to provide data to support the ecological risk assessment of soil animals caused by the combined pollution of MPs and coexisting pesticides.


Subject(s)
Oligochaeta , Soil Pollutants , Animals , Microplastics/toxicity , Polyethylene/toxicity , Polyethylene/metabolism , Plastics/toxicity , Oligochaeta/metabolism , Soil Pollutants/analysis , Soil
15.
Water Res ; 233: 119723, 2023 Apr 15.
Article in English | MEDLINE | ID: mdl-36801572

ABSTRACT

In this study, abiotic transformation of an important strobilurin fungicide, kresoxim-methyl, was investigated under controlled laboratory conditions for the first time by studying its kinetics of hydrolysis and photolysis, degradation pathways and toxicity of possibly formed transformation products (TPs). The results indicated that kresoxim-methyl showed a fast degradation in pH9 solutions with DT50 of 0.5 d but relatively stable under neutral or acidic environments in the dark. It was prone to photochemical reactions under simulated sunlight, and the photolysis behavior was easily affected by different natural substances such as humic acid (HA), Fe3+and NO3-which are ubiquitous in natural water, showing the complexity of degradation mechanisms and pathways of this chemical compound. The potential multiple photo-transformation pathways via photoisomerization, hydrolyzation of methyl ester, hydroxylation, cleavage of oxime ether and cleavage of benzyl ether were observed. 18 TPs generated from these transformations were structurally elucidated based on an integrated workflow combining suspect and nontarget screening by high resolution mass spectrum (HRMS), and two of them were confirmed with reference standards. Most of TPs, as far as we know, have never been described before. The in-silico toxicity assessment showed that some of TPs were still toxic or very toxic to aquatic organisms, although they exhibit lower aquatic toxicity compared to the parent compound. Therefore, the potential hazards of the TPs of kresoxim-methyl merits further evaluation.


Subject(s)
Sunlight , Water Pollutants, Chemical , Strobilurins , Mass Spectrometry , Water Pollutants, Chemical/chemistry , Photolysis
16.
Sci Total Environ ; 892: 164418, 2023 Sep 20.
Article in English | MEDLINE | ID: mdl-37257596

ABSTRACT

Phytoremediation provides substantial advantages, including eco-friendliness, cost-effectiveness, efficiency, and visual appeal. However, the current knowledge of the factors influencing phytoremediation in pesticide-contaminated environments remains limited. It is critical to understand phytoremediation and the factors affecting the variation in removal efficiency. In this study, we compiled 72 previous research articles to quantify plant-induced improvements in removal efficiency and identify factors that influence variations in phytoremediation behavior through meta-analysis. We observed a significant increase in the removal efficiency of phytoremediation compared to the control group which did not involve phytoremediation. Pesticides significantly affect removal efficiency in terms of their modes of action, substance group, and properties. Plants demonstrated higher efficiency in remediating environments contaminated with pesticides possessing lower molecular masses and log Kow values. Plant species emerged as a crucial determinant of variations in removal efficiency. Annual plants exhibited a 1.45-fold higher removal efficiency than perennial plants. The removal efficiencies of different plant types decreased in the following order: agri-food crops > aquatic macrophytes > turfgrasses > medicinal plants > forage crops > woody trees. The Gramineae family, which was the most prevalent, demonstrated a robust and consistent phytoremediation ability. This study offers a more comprehensive triangular relationship between removal efficiency, pesticides, and plants, expanding the traditional linear model. Our findings offer valuable insights into the behavior of phytoremediation in pesticide-contaminated environments and the factors determining its success, ultimately guiding further research toward developing strategies for higher removal efficiency in phytoremediation.


Subject(s)
Pesticides , Soil Pollutants , Biodegradation, Environmental , Poaceae , Crops, Agricultural , Trees
17.
Sci Total Environ ; 883: 163529, 2023 Jul 20.
Article in English | MEDLINE | ID: mdl-37068689

ABSTRACT

As a typical triazole fungicide, difenoconazole is extensively used to control plant diseases; however, its residue in environmental waters poses a risk to aquatic organisms. In this study, we investigated the acute toxicity of different life stages and sub-lethal toxicity in embryonic yolk sac stage of difenoconazole to zebrafish, and the developmental toxicity in F1 generation of parents exposed to difenoconazole at different life stages of zebrafish. Furthermore, we used transcriptomics to explore the potential mechanisms of difenoconazole on the F1 larvae of parents exposed to the chemical at the embryonic stage. The results of this study showed that developmental defects were observed in the F1 embryo/larvae of parents exposed to 3, 30, and 300 µg/L of difenoconazole at different (embryo, larval, juvenile, and adult) life stages, and exposure to difenoconazole at the embryonic stage caused more severe developmental toxicity than those at other life stages. Developmental defects (malformation, inhibition of heartbeat and body length) were observed in the F1 embryos and larvae of parents exposed to difenoconazole at the embryonic stage. In addition, the total cholesterol and triglyceride contents were significantly reduced in the F1 larvae, and RNA-seq analysis revealed significant alterations in the expression of nine genes (msmo1, hsd17b7, sc5d, tm7sf2, ebp, cyp2r1, lss, cyp51, and cyp27b1) in the steroid synthesis pathway. This is suggested that F1 larvae of parents exposed to difenoconazole at the embryonic stage show abnormalities in the steroid biosynthetic pathway. These results reveal the differences in toxicity of difenoconazole to zebrafish at different life stages, improve studies on difenoconazole toxicity to zebrafish, and provide a new perspective for assessing the risk of contaminants to aquatic organisms.


Subject(s)
Water Pollutants, Chemical , Zebrafish , Animals , Zebrafish/physiology , Embryo, Nonmammalian/metabolism , Water Pollutants, Chemical/toxicity , Water Pollutants, Chemical/metabolism , Triazoles/toxicity , Triazoles/metabolism , Larva , Steroids/metabolism
18.
Chemosphere ; 303(Pt 3): 135282, 2022 Sep.
Article in English | MEDLINE | ID: mdl-35691395

ABSTRACT

To reduce detrimental effects to the environment, the application of prothioconazole and its metabolites requires comprehensive evaluation, which has been dine for the first time in this study. The behavior of prothioconazole, including degradation and sorption under aerobic and anaerobic conditions, was evaluated in three common soil types and two types of water-sediment systems under different environmental conditions. Individual and joint toxicities of prothioconazole and its metabolites, M01 and M04, on aquatic organisms, including the Gobiocypris rarus, are also investigated in the present study. Under aerobic and anaerobic conditions, the half-life of prothioconazole in the three types of soils ranged from 0.0565 to 2.27 days and 0.138-1.73 days, respectively. Under aerobic conditions, the half-life of prothioconazole in the Hunan paddy area and Beijing Qidu reservoir water-sediment samples were 2.18 and 1.58 days, respectively. In soil and water-sediment samples, prothioconazole degraded to M01 and M04, and the formation rate of M04 was higher than M01 under aerobic condition. M04 and M01 gradually increased to a peak value in soil and water-sediment systems, then decreased over time, while prothioconazole gradually decreased. The half-life of prothioconazole in soils was lower than its metabolites, with the DT50 of metabolites ranging from 16.6 to 99.6 days, 15.8 and 50.7 days for M01 and M04 under aerobic condition, respectively. While the adsorption capacities (Kf values) of M04 and M01 ranged from 2.09 to 88.92 and 8.98 to 243.30 (µg/g)/(mg/L), respectively, in the three soils. Regarding toxicity to aquatic organisms, the metabolites did not show higher toxicity than prothioconazole, except M01 on Gobiocypris rarus. Joint toxicity assays showed that mixtures of prothioconazole with its metabolites exhibited higher toxicity than any compound individually and indicated synergistic interactions could occur at equitoxic ratios and equivalent concentrations. This study provides a comprehensive investigation on the fate and environmental risk posed by prothioconazole.


Subject(s)
Soil Pollutants , Soil , Soil Pollutants/analysis , Triazoles/toxicity , Water
19.
J Agric Food Chem ; 70(51): 16146-16155, 2022 Dec 28.
Article in English | MEDLINE | ID: mdl-36515273

ABSTRACT

This study investigated the degradation of strobilurin fungicide kresoxim-methyl (KM) in three typical agricultural soils from China by aerobic and anaerobic degradation experiments, focusing on degradation kinetics of KM, identification of transformation products (TPs), and prediction of toxicity end points via in silico approaches. KM showed a pronounced biphasic degradation in different soils and could rapidly degrade, with DT50 of <3 days. Four TPs were identified by high-resolution mass spectrometry (HRMS), and three of them have never been reported before. Possible degradation pathways of KM in soil were proposed, including hydrolysis, oxidation, and reduction, and the main mechanism involved in the biodegradation of KM was the hydrolysis of methyl ester regardless of aerobic or anaerobic conditions. The results of toxicity evaluation indicated that some TPs are more toxic than KM and may have a developmental toxicity and mutagenicity, and further risk assessment should be carried out.


Subject(s)
Fungicides, Industrial , Water Pollutants, Chemical , Strobilurins , Soil/chemistry , Mass Spectrometry , Fungicides, Industrial/metabolism , Kinetics , Water Pollutants, Chemical/analysis
20.
Sci Rep ; 12(1): 15939, 2022 09 24.
Article in English | MEDLINE | ID: mdl-36153424

ABSTRACT

Application of chemical pesticides is currently the main effective method to control tobacco whitefly (Bemisa tabaci) in tomato in China. The B. tabaci control efficacy of three systemic insecticides (thiamethoxam, sulfoxaflor and cyantraniliprole) by pre-transplant soil drenching with anti-insect nets throughout the tomato growth period was evaluated in two tomato greenhouses in the suburbs of Beijing, China, in 2018 and 2019. In two greenhouse trials, thiamethoxam 25% water dispersible granules (WDG) at a field rate of 21 g a.i./hm2, sulfoxaflor 22% aqueous suspension (AS) at 18 g a.i./hm2 or cyantraniliprole 10% oil-based suspension concentrate (OD) at 18 g a.i./hm2 applied via soil drenching before seedling transplanting in combination with white anti-insect nets (50 mesh) all effectively controlled the damage to B. tabaci and resulted in a low density of adults and eggs during the entire growing season, which was significantly lower than application of thiamethoxam, sulfoxaflor or cyantraniliprole via soil drenching before seedling transplanting without anti-insect net treatments or anti-insect nets alone (P < 0.05). All of the above treatments provided significantly better results than the untreated control (P < 0.05). All chemically treated tomato fruits had acceptable insecticide residuals that were lower than the corresponding maximum residue limits. The results suggest that application of thiamethoxam 25% WDG at a field rate of 21 g a.i./hm2, sulfoxaflor 22% AS at 18 g a.i./hm2 or cyantraniliprole 10% OD at 18 g a.i./hm2 by pre-transplant soil drenching combined with anti-insect nets could be recommended to control B. tabaci throughout the tomato growth period as part of integrated pest management programs in China.


Subject(s)
Hemiptera , Insecticides , Pesticides , Solanum lycopersicum , Animals , Insecticides/analysis , Insecticides/pharmacology , Pesticides/pharmacology , Pyrazoles , Pyridines , Seedlings/chemistry , Soil/chemistry , Sulfur Compounds , Thiamethoxam/pharmacology , Nicotiana , Water/pharmacology , ortho-Aminobenzoates
SELECTION OF CITATIONS
SEARCH DETAIL