Mechanisms of adsorption and functionalization of biochar for pesticides: A review.

Agricultural production relies heavily on pesticides. However, factors like inefficient application, pesticide resistance, and environmental conditions reduce their effective utilization in agriculture. Subsequently, pesticides transfer into the soil, adversely affecting its physicochemical properties, microbial populations, and enzyme activities. Different pesticides interacting can lead to combined toxicity, posing risks to non-target organisms, biodiversity, and organism-environment interactions. Pesticide exposure may cause both acute and chronic effects on human health. Biochar, with its high specific surface area and porosity, offers numerous adsorption sites. Its stability, eco-friendliness, and superior adsorption capabilities render it an excellent choice. As a versatile material, biochar finds use in agriculture, environmental management, industry, energy, and medicine. Added to soil, biochar helps absorb or degrade pesticides in contaminated areas, enhancing soil microbial activity. Current research primarily focuses on biochar produced via direct pyrolysis for pesticide adsorption. Studies on functionalized biochar for this purpose are relatively scarce. This review examines biochar's pesticide absorption properties, its characteristics, formation mechanisms, environmental impact, and delves into adsorption mechanisms, functionalization methods, and their prospects and limitations.

Storage time does not influence pregnancy and neonatal outcomes for first single vitrified high-quality blastocyst transfer cycle.

RESEARCH QUESTION: Does blastocyst storage time have an impact on pregnancy and neonatal outcomes following the first single vitrified/warmed high-quality blastocyst transfer cycle for young women? DESIGN: Retrospective cohort study in a university-affiliated reproductive medical centre. RESULTS: A total of 2938 patients undergoing their first frozen embryo transfer (FET) cycle with a single high-quality blastocyst (Day 5: 3BB and above; Day 6: 4BB and above) transferred were divided into five groups: Group A with storage time ≤3 months (n = 1621), Group B with storage time of 4-6 months (n = 657), Group C with storage time of 7-12 months (n = 225), Group D with storage time of 13-24 months (n = 104), and Group E with storage time of 25-98 months (n = 331). After adjusting for confounding factors by multivariate logistic regression, there were no significant differences in live birth rate [Group A as reference; Group B: adjusted odds ratio (aOR) 0.954 (95% CI 0.791- 1.151); Group C: aOR 0.905 (95% CI 0.674-1.214); Group D: aOR 0.727 (95% CI 0.474-1.114); Group E: aOR 1.185 (955 CI 0.873-1.608)], ß-human-chorionic-gonadotropin-positive rate, clinical pregnancy rate and miscarriage rate between Group A and the other groups. Among all singletons born after FET, there were no significant differences with regards to gestational age, preterm birth, birthweight, low birthweight, high birthweight and macrosomia. CONCLUSION: Long-term cryostorage of human vitrified high-quality blastocysts does not affect pregnancy or neonatal outcomes.

Effects of Cinobufagin on the Proliferation, Migration, and Invasion of H1299 Lung Cancer Cells.

Cinobufagin (CB), with its steroidal nucleus structure, is one of the major, biologically active components of Chan Su. Recent studies have shown that CB exerts inhibitory effects against numerous cancer cells. However, the effects of CB regarding the metastasis of non-small cell lung cancer (NSCLC) and the involved mechanisms need to be further studied. The purpose of the present study aimed to report the inhibitory function of CB against proliferation and metastasis of H1299 cells. CB inhibited proliferation of H1299 lung cancer cells with an IC50 value of 0.035±0.008 µM according to the results of MTT assays. Antiproliferative activity was also observed in colony forming cell assays. In addition, 5-ethynyl-2'-deoxyuridine (EdU) retention assays revealed that CB significantly inhibited the rate of DNA synthesis in H1299 cells. Moreover, results of the scratch wound healing assays and transwell migration assays displayed that CB exhibited significant inhibition against migration and invasion of H1299 cells. Furthermore, CB could concentration-dependently reduce the expression of integrin α2, ß-catenin, FAK, Src, c-Myc, and STAT3 in H1299 cells. These western blotting results indicated that CB might target integrin α2, ß-catenin, FAK and Src to suppress invasion and migration of NSCLC, which was consistent with the network pharmacology analysis results. Collectively, findings of the current study suggest that CB possesses promising activity against NSCLC growth and metastasis.

Residual Behavior and Dietary Risk Assessment of Chlorfenapyr and Its Metabolites in Radish.

Chlorfenapyr, as a highly effective and low-toxicity insect growth regulation inhibitor, has been used to control cross-cruciferous vegetable pests. However, the pesticide residue caused by its application threatens human health. In this paper, the residue digestion and final residue of chlorfenapyr in radish were studied in a field experiment. The results of the dynamic digestion test showed that the half-life of chlorfenapyr in radish leaves ranged from 6.0 to 6.4 days, and the digestion rate was fast. The median residual values of chlorfenapyr in radish and radish leaves at 14 days after treatment were 0.12 and 3.92 mg/kg, respectively. The results of the dietary intake risk assessment showed that the national estimated daily intake (NEDI) of chlorfenapyr in various populations in China were 0.373 and 5.66 µg/(kg bw·d), respectively. The risk entropy (RQ) was 0.012 and 0.147, respectively, indicating that the chronic dietary intake risk of chlorfenapyr in radish was low. The results of this study provided data support and a theoretical basis for guiding the scientific use of chlorfenapyr in radish production and evaluating the dietary risk of chlorfenapyr in vegetables.

Stereoselective bioactivity, toxicity and degradation of novel fungicide sedaxane with four enantiomers under rice-wheat rotation mode.

Sedaxane was a novel chiral fungicide that contains four enantiomers. Unfortunately, the stereoselective bioactivity, toxicity and degradation of sedaxane have not been clarified. In this study, we identified the absolute configuration of the four sedaxane enantiomers at first time. The stereoselective bioactivity toward three wheat and rice pathogens, stereoselective acute toxicity to aquatic organisms (Selenastrum capricornutum and Daphnia magna), and stereoselective degradation of sedaxane were studied. The 1 S,2S-(+)-sedaxane possessed 5.4-7.3 times greater bioactivity than 1 R,2R-(-)-sedaxane to Rhizoctonia solani and Rhizoctonia cerealis. Contrarily, the 1 R,2S-(+)-sedaxane had 4.2 times greater activity than 1 S,2S-(+)-sedaxane against Fusarium graminearum. The 1 R,2R-(-)-sedaxane had 2.8 times greater toxicity than 1 S,2S-(+)-sedaxane to S. capricornutum. The chiral determination method used ultrahigh-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The recovery of sedaxane stereoisomers ranged from 83.1 % to 98.2 %, with RSDs (Relative standard deviations) of 1.2 %- 8.4 %. The trans-sedaxane existed stereoselective degradation phenomenon in the rice-wheat rotation mode, and 1 S,2S-(+)-sedaxane was preferentially degraded. Our results would provide scientific importance and practical guidance to the safety evaluation of chiral pesticides.

The fate and effect of chlorpyrifos and lambda-cyhalothrin in soybean (Glycine max L. Merril) field.

Soybean pod borer (Leguminivora glycinivorella) is an important pest in soybean production, and chemical pesticides was major way for prevention. However, it is difficult to balance the efficiency and safety of pesticide application. In this paper, we evaluated safety and effectiveness of common insecticides (chlorpyrifos and lambda-cyhalothrin) on soybean from three aspects, including distribution, dissipation and control effect, around three major soybean production area (Anhui, Jilin and Shandong) in China. For chlorpyrifos, the initial deposition of each position (upper leaf, lower leaf, upper stem, lower stem, soybean and root) was determinated for 0.23 mg/kg to 70.7 mg/kg, and the half-lifes ranged from 1.96 days to 5.36 days. For lambda-cyhalothrin, the initial deposition of the position was determinated for 0.10 mg/kg to 2.54 mg/kg, and the half-lifes ranged from 2.45 days to 7.26 days. We found that the target insecticides were major deposition and faster degradation in upper stem and leaf. Through comparing the relationship between field control effect and residue, it can be suggested that 40% chlorpyrifos EC and 2.5% lambda-cyhalothrin WE should be sprayed at 600 g a.i./ha and 5.63 g a.i./ha for SPB prevention. This study enhanced our understanding of distribution, dissipation and relationship between residue and control effect. The results provided data support for guiding the precise and scientific application of chemical insecticides on soybean.

Semi-quantitative and quantitative detection of ochratoxin A in agricultural by-products using a self-assembling immunochromatographic strip.

BACKGROUND: The toxicity and health risks of mycotoxins have encouraged increased awareness and strict monitoring of these contaminants in agricultural by-products. In this paper, we developed and tested a sensitive, selective, and self-assembling immunochromatographic (IC) strip for on-site detection of ochratoxin A (OTA). We were able to demonstrate semi-quantitative and quantitative detection of OTA in agricultural by-product samples. RESULTS: The optimized IC strip had a limit of detection (LOD) of 0.5 ng mL-1 OTA using the naked eye for semi-quantitative detection. When a digitized strip reader was used to achieve quantitative results, the LOD for OTA was reduced to 0.1 ng mL-1 with a linear detection range of 0.1-10 ng mL-1 . We also evaluated the specificity, stability, accuracy, and precision of the IC strip and demonstrated high performance in all of these areas. We then confirmed the ability of the IC strip to visually detect OTA contamination in authentic agricultural by-product samples from the markets in China. Furthermore, quantitative detection of OTA using the IC strip showed that the concentration of OTA ranged from 1.7 to 101.3 ng g-1 in the positive agricultural by-product samples, correlating well with the measurements obtained via liquid chromatography with tandem mass spectrometry. CONCLUSION: The results indicated that this proposed IC strip was capable of sensitive, semi-quantitative, quantitative, and on-site detection of OTA contamination in agricultural by-product samples. © 2020 Society of Chemical Industry.

Osthole: an overview of its sources, biological activities, and modification development.

Osthole, also known as osthol, is a coumarin derivative found in several medicinal plants such as Cnidium monnieri and Angelica pubescens. It can be obtained via extraction and separation from plants or total synthesis. Plenty of experiments have suggested that osthole exhibited multiple biological activities covering antitumor, anti-inflammatory, neuroprotective, osteogenic, cardiovascular protective, antimicrobial, and antiparasitic activities. In addition, there has been some research done on the optimization and modification of osthole. This article summarizes the comprehensive information regarding the sources and modification progress of osthole. It also introduces the up-to-date biological activities of osthole, which could be of great value for its use in future research.

Design, Synthesis and Cytotoxicity Evaluation of Novel Indole Derivatives Containing Benzoic Acid Group as Potential AKR1C3 Inhibitors.

Castration-resistant prostate cancer (CRPC) is a fatal, metastatic form of prostate cancer, characterized by reactivation of the androgen axis. Aldo-keto reductase 1C3 (AKR1C3) converts androstenedione (AD) and 5α-androstanedione to testosterone (T) and 5α-dihydrotestosterone (DHT), respectively. In CRPC, AKR1C3 is upregulated and implicated in drug resistance and has been regarded as a potential therapeutic target. Here we examined a series of indole derivatives containing benzoic acid or phenylhydroxamic acid and found that 4-({3-[(3,4,5-trimethoxyphenyl)sulfanyl]-1H-indol-1-yl}methyl)benzoic acid (3e) and N-hydroxy-4-({3-[(3,4,5-trimethoxyphenyl)sulfanyl]-1H-indol-1-yl}methyl)benzamide (3q) inhibited 22Rv1 cell proliferation with IC50 values of 6.37 µM and 2.72 µM, respectively. In enzymatic assay, compounds 3e and 3q exhibited potent inhibitory effect against AKR1C3 (IC50 =0.26 and 2.39 µM, respectively). These results indicated that compounds 3e and 3q might be useful leads for further investigation of more potential AKR1C3 inhibitors used for CRPC.

Determination of phenamacril residues in flour and rice based on Z-Sep+ using ultra-high-performance liquid chromatography-tandem mass spectrometry.

Phenamacril is a new broad-spectrum fungicide that is commonly used for the control of fungal diseases in wheat and rice. In this study, ultra-high-performance liquid chromatography-tandem mass spectrometry was used to establish a method for analyzing the residual phenamacril in flour and rice based on the improved QuEChERS (quick, easy, cheap, effective, rugged and safe) method using Z-Sep+ as the adsorbent in the pre-treatment process. The average recovery of phenamacril in flour and rice was 82.2-96.0%, the relative standard deviation was 2.1-5.6% and the limit of quantification was 0.5 µg/kg. The accuracy and sensitivity of this method meet the requirements for residue analysis. The method was applied to commercially available flour and rice samples, and the detected concentrations of phenamacril were 0.005-0.033 mg/kg. This method provides technical support for the safety evaluation of phenamacril.

Dissipation Dynamics and Dietary Risk Assessment of Kresoxim-Methyl Residue in Rice.

Kresoxim-methyl is a high-efficiency and broad-spectrum fungicide used for the control of rice fungal diseases; however, its residues after application potentially threaten human health. Investigations on the dissipation of kresoxim-methyl residue in rice field systems and dietary risk assessment of kresoxim-methyl in humans are limited. The present study employed the QuEChERS-GC-MS/MS method for residue analysis of kresoxim-methyl in rice plants, brown rice, and rice husks. The samples were extracted with acetonitrile and purified by PSA, C18 column, and GCB. The average recovery of the spiked target compounds in the three matrices was between 80.5% and 99.3%, and the RSD was between 2.1% and 7.1%. The accuracy and precision of the method is in accordance with the requirements of residue analysis methods. Dissipation dynamic testing of kresoxim-methyl in rice plants indicated a half-life within the range of 1.8⁻6.0 days, and a rapid dissipation rate was detected. Dietary intake risk assessment showed that the national estimated daily intake (NEDI) of kresoxim-methyl in various Chinese subpopulations was 0.022⁻0.054 µg/(kg bw·days), and the risk quotient (RQ) was 0.0000055⁻0.00014%. These findings indicate that the risk for chronic dietary intake of kresoxim-methyl in brown rice is relatively low. The present study provides information and theoretical basis for guiding the scientific use of kresoxim-methyl in rice fields and evaluating its dietary risk in brown rice.

Enantioselective Acute Toxicity and Bioactivity of Carfentrazone-ethyl enantiomers.

The stereoselective herbicidal bioactivity and toxicity toward aquatic organisms of carfentrazone-ethyl enantiomers were investigated. The results showed that there was significant enantioselective acute toxicity toward Selenastrum bibraianum. In addition, S-(-)-carfentrazone-ethyl was 4.8 times more potent than R-(+)-isomer. However, a slight enantioselectivity was observed for Daphnia magna and Danio rerio. The stereoselective herbicidal bioactivity of carfentrazone-ethyl enantiomers was observed by assessing maize root-length inhibition. The results clarified that S-(-)-carfentrazone-ethyl (EC50 1.94 mg/L) > Rac-carfentrazone-ethyl (EC50 2.18 mg/L) > R-(+)-carfentrazone-ethyl (EC50 3.96 mg/L). The herbicidal bioactivity of S-(-)-carfentrazone-ethyl was 2 times higher more than R-(+)-isomer. The mechanism of enantioselective bioactivity was illustrated using molecular simulation software. The GlideScore energies of S-(-)-carfentrazone-ethyl and R-(+)-carfentrazone-ethyl were - 6.15 kcal/mol and - 5.59 kcal/mol, indicating that the S-form has a greater affinity to the active site of protoporphyrinogen oxidase, which is consistent with the results of the bioactive assay. This study can rise the significance of risk assessments for carfentrazone-ethyl herbicide.

Structure Identification and In Vitro Anticancer Activity of Lathyrol-3-phenylacetate-5,15-diacetate.

Natural products from the genus Euphorbia show attention-attracting activities, such as anticancer activity. In this article, classical isolation and structure identification were used in a study on Caper Euphorbia Seed. Subsequently, MTT and wound healing assays, flow cytometry, western blotting, Hoechst 33258 staining and fluorescence microscopy examination were applied to investigate the anticancer activity of the obtained compounds. In a result, lathyrol-3-phenyl- acetate-5,15-diacetate (deoxy Euphorbia factor L1, DEFL1) was isolated from Caper Euphorbia Seed. Moreover, the NMR signals were totally assigned. DEFL1 showed potent inhibition against lung cancer A549 cells, with an IC50 value of 17.51 ± 0.85 µM. Furthermore, DEFL1 suppressed wound healing of A549 cells in a concentration-dependent manner. Mechanically, DEFL1 induced apoptosis, with involvement of an increase of reactive oxygen species (ROS), decrease of mitochondrial membrane potential (ΔΨm), release of cytochrome c, activity raise of caspase-9 and 3. Characteristic features of apoptosis were observed by fluorescence microscopy. In summary, DEFL1 inhibited growth and induced apoptosis in lung cancer A549 cells via a mitochondrial pathway.

[Neuroprotective effect screening and the mechanism of 10 kinds of coumarin derivatives].

The study reports the detection of neuroprotective effect of 10 kinds of coumarin derivatives and explores their possible mechanism. MTT method was used to screen the neuroprotective effect of 10 coumarin derivatives on neurotoxic agents (Aß25-35 and rotenone) or OGD (oxygen-glucose deprivation). A compound with better protective effect was obtained. Then the effect of this compound on neurotoxic agents on PC12 was detected by the morphological observation. Furthermore, the effect of compound 3 on microglia with lipopolysaccharide (LPS) induced inflammation was detected. And the inflammatory factor was tested. Finally, direct free radical scavenging ability was detected. Compound 3 was found to be the best compound through three neurons toxic models. Not only compound 3 ameliorated cell viability reduced by three neurons toxic models, but also significantly inhibited the production of inflammatory factor (TNF-α and IL-1ß). And its free radical scavenging ability is very good, especially the effect on superoxide anion, which is comparable with vitamin C. The significant scavenging effect of compound 3 on superoxide anion might be the mechanism of the neuroprotection. Compound 3 as a potential neural cell protective agent merits further investigation.

Exo I-based cyclic digestion coupled with synergistic enhancement strategy for integrating dual-mode optical aptasensor platform.

The improvement of dual-mode techniques was of particular interest to researchers, which might enhance the detection performance and applicability. Here, a dual-mode optical aptasensor (DO-aptasensor) platform based on exonuclease I (Exo I) cyclic digestion and synergistic enhancement strategy had proposed for zearalenone (ZEN). Following the preparation of dumbbell-shaped signal probe, the Exo I-based cyclic digestion amplification performed, and then the synergistic enhancement effect carried out to achieve the Poly-HRP-based colorimetry and FAM-SGI-based fluorescence. The efficient homogeneous system realized through the magnetic separation, while the signal interference further eliminated by the graphene oxide (GO). The LOD values were as low as 0.067 ng mL-1 for colorimetry mode and 0.009 ng mL-1 for fluorescence mode, which reduced 23-fold and 172-fold than ELASA by same ZEN-Apt. This promising platform gave rise to a dual-mode optical readout, improved sensitivity and positively correlated detection. Meanwhile, the DO-aptasensor also exhibited the acceptable specificity, desirable reliability and excellent practicability. This novel avenue of aptasensor platform hold great potential for dual-mode optical monitoring of other targets, which can further expand the application scope of Exo I-based signal amplification and synergistic enhancement effect.

Mechanism Insights into the Enantioselective Bioactivity and Fumonisin Biosynthesis of Mefentrifluconazole to Fusarium verticillioides.

The occurrence of maize ear rot caused by Fusarium verticillioides (F. verticillioides) poses a threat to the yield and quality of maize. Mefentrifluconazole enantiomers appear to have strong stereoselective activity against F. verticillioides and cause differences in fumonisin production. We evaluated the stereoselective activity of mefentrifluconazole enantiomers by determining inhibition of the strain, hyphae, and conidia. Strain inhibition by R-(-)-mefentrifluconazole was 241 times higher than S-(+)-mefentrifluconazole and 376 times higher in conidia inhibition. For the mechanism of the enantioselective bioactivity, R-mefentrifluconazole had stronger binding to proteins than S-(+)-mefentrifluconazole. Under several concentration conditions, the fumonisin concentration was 1.3-24.9-fold higher in the R-(-)-mefentrifluconazole treatment than in the S-(+)-mefentrifluconazole treatment. The R-enantiomer stimulated fumonisin despite a higher bioactivity. As the incubation time increased, the stimulation of the enantiomers on fumonisin production decreased. R-(-)-Mefentrifluconazole stimulated higher fumonisin production in F. verticillioides at 25 °C compared to 30 °C. This study established a foundation for the development of high-efficiency and low-risk pesticides.

Hyaluronic acid modified nanocarriers for aerosolized delivery of verteporfin in the treatment of acute lung injury.

Verteporfin (VER), a photosensitizer used in macular degeneration therapy, has shown promise in controlling macrophage polarization and alleviating inflammation in acute lung injury (ALI)/acute respiratory distress syndrome (ARDS). However, its hydrophobicity, limited bioavailability, and side effects hinder its therapeutic potential. In this study, we aimed to enhance the therapeutic potential of VER through pulmonary nebulized drug delivery for ALI/ARDS treatment. We combined hydrophilic hyaluronic acid (HA) with an oil-in-water system containing a poly(lactic acid-co-glycolic acid) (PLGA) copolymer of VER to synthesize HA@PLGA-VER (PHV) nanoparticles with favorable surface characteristics to improve the bioavailability and targeting ability of VER. PHV possesses suitable electrical properties, a narrow size distribution (approximately 200 nm), and favorable stability. In vitro and in vivo studies demonstrated the excellent biocompatibility, safety, and anti-inflammatory responses of the PHV by suppressing M1 macrophage polarization while inducing M2 polarization. The in vivo experiments indicated that the treatment with aerosolized nano-VER (PHV) allowed more drugs to accumulate and penetrate into the lungs, improved the pulmonary function and attenuated lung injury, and mortality of ALI mice, achieving improved therapeutic outcomes. These findings highlight the potential of PHV as a promising delivery system via nebulization for enhancing the therapeutic effects of VER in ALI/ARDS.

Cytotoxic metabolites from Sinularia levi supported by network pharmacology.

The in-vitro anti-proliferative evaluation of Sinularia levi total extract against three cell lines revealed its potent effect against Caco-2 cell line with IC50 3.3 µg/mL, followed by MCF-7 and HepG-2 with IC50 6.4 µg/mL and 8.5 µg/mL, respectively, in comparison to doxorubicin. Metabolic profiling of S. levi total extract using liquid chromatography coupled with high-resolution electrospray ionization mass spectrometry (LC-HR-ESI-MS) revealed the presence of phytoconstituents clusters consisting mainly of steroids and terpenoids (1-20), together with five metabolites 21-25, which were additionally isolated and identified through the phytochemical investigation of S. levi total extract through various chromatographic and spectroscopic techniques. The isolated metabolites included one sesquiterpene, two steroids and two diterpenes, among which compounds prostantherol (21) and 12-hydroperoxylsarcoph-10-ene (25) were reported for the first time in Sinularia genus. The cytotoxic potential evaluation of the isolated compounds revealed variable cytotoxic effects against the three tested cell lines. Compound 25 was the most potent with IC50 value of 2.13 ± 0.09, 3.54 ± 0.07 and 5.67 ± 0.08 µg/mL against HepG-2, MCF-7 and Caco-2, respectively, followed by gorgosterol (23) and sarcophine (24). Additionally, network analysis showed that cyclin-dependent kinase 1 (CDK1) was encountered in the mechanism of action of the three cancer types. Molecular docking analysis revealed that CDK1 inhibition could possibly be the reason for the cytotoxic potential.

Enantioselective Degradation and Bioactivity Mechanism of a New Chiral Fungicide Fluindapyr in Paddy Ecosystems.

Fluindapyr is a novel chiral succinate dehydrogenase inhibitor used to control fungal diseases. The enantioselective effects of fluindapyr in paddy ecosystems are unknown. We developed a new chiral determination method of fluindapyr using ultrahigh performance liquid chromatography tandem mass spectrometry. The absolute configuration of the fluindapyr enantiomers was identified by an electron circular dichroism model. A new husk-based biochar material was used to optimize and establish a QuEchERs method for paddy soil determination. Under anaerobic conditions, the half-lives of R-fluindapyr and S-fluindapyr in paddy soil were 69.6 and 101.8 days, respectively. R-fluindapyr degraded more rapidly than S-fluindapyr. S-fluindapyr was 87.8 times more active against Rhizoctonia solani than R-fluindapyr. The enantioselective bioactivity mechanism was illustrated by molecular docking between the fluindapyr enantiomers and SDH of R. solani. The binding powers of R-fluindapyr and S-fluindapyr to proteins were -32.12 and - 42.91 kcal/mol, respectively. This study reports the stereoselectivity of fluindapyr about determination, degradation, bioactivity, and its mechanism. It provides a foundation for an in-depth study of fluindapyr at the enantiomer level.

Ecological threat caused by malathion and its chiral metabolite in a honey bee-rape system: Stereoselective exposure risk and the mechanism revealed by proteome.

Honey bees play an important role in the ecological environment. Regrettably, a decline in honey bee colonies caused by chemical insecticides has occurred throughout the world. Potential stereoselective toxicity of chiral insecticides may be a hidden source of danger to bee colonies. In this study, the stereoselective exposure risk and mechanism of malathion and its chiral metabolite malaoxon were investigated. The absolute configurations were identified using an electron circular dichroism (ECD) model. Ultrahigh-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was used for chiral separation. In pollen, the initial residues of malathion and malaoxon enantiomers were 3571-3619 and 397-402 µg/kg, respectively, and R-malathion degraded relatively slowly. The oral LD50 values of R-malathion and S-malathion were 0.187 and 0.912 µg/bee with 5 times difference, respectively, and the malaoxon values were 0.633 and 0.766 µg/bee. The Pollen Hazard Quotient (PHQ) was used to evaluate exposure risk. R-malathion showed a higher risk. An analysis of the proteome, including Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and subcellular localization, indicated that energy metabolism and neurotransmitter transport were the main affected pathways. Our results provide a new scheme for the evaluation of the stereoselective exposure risk of chiral pesticides to honey bees.