Recognition mechanism and sequence optimization of organophosphorus pesticides aptamers for better monitoring contaminations in food

Aptamers as a kind of biological recognition element have shown great potential in monitoring and the rapid quantification of organophosphorus pesticides(OPPs). However, molecules of OPPs are structurally similar and original aptamers selected by systematic evolution of ligands by exponential enrichment are usually long-chain bases, which hamper the further application under OPPs-aptamer recognition. The aim of the research was to develop a new strategy to design oligonucleotide sequences for binding OPPs by combination of experimental and molecular modeling methods. 3D models of aptamers binding OPPs were constructed, and binding energy and the most probable binding site for the OPPs were then determined by molecular docking, and the binding sites were further confirmed by the results of 2-AP replaced experiments. Based on the docking results, a new aptamer for detection 4 representative OPPs with only 29 bases was designed by reasonable truncation and mutation of the reported aptamer(named S4-29). The interaction between this new aptamer and OPPs were analyzed by molecular docking, microscale thermophoresis, circular dichroism and fluorometric analysis. The results revealed that the new aptamer exhibit more superior recognition performance to OPPs, which can be promote the monitoring ability of OPPs contaminations in food.

Determination of 14 Organophosphorus Pesticide Residues in Mutton by Gel Permeation Chromatography-Gas Chromatography-Mass Spectrometry(GPC-GC-MS)

[Objectives]This study was conducted to purify mutton samples by gel permeation chromatography(GPC).[Methods]Fourteen organophosphorus pesticide residues in samples were qualitatively and quantitatively analyzed by gas chromatography-mass spectrometry(GC-MS)in selective ion scanning mode(SIM).[Results]The organophosphorus pesticide standard solutions showed good linearity in the mass concentration range of 0.1-10.0μg/ml with correlation coefficients(r)not lower than 0.999,and the detection limits(S=3 N)ranged from 0.01 to 0.05 mg/kg.The average recovery values were in the range of 80.2%-99.7%,with relative standard deviations(RSDs,n=3)in the range of 1.8%-6.3%,at the addition levels of 0.5,1.0 and 2.0 mg/kg.[Conclusions]The method is simple,sensitive and accurate,and can be used for the determination of organophosphorus pesticide residues in mutton.

Comparison of Two Procedures for Extraction and Clean-up of Organophosphorus and Pyrethroid Pesticides in Sediment

Two procedures were compared for extraction and clean-up of 20organophosphorus and 19 pyrethroid pesticides in sediment to identify the more effective procedurefor groups of pesticides or individual compounds. In Procedure I, methanol/water and n-hexane wereused for extraction, and 1:10 (v/v) dichloromethane in n-hexane and acetone were used as eluents foreluting the analyte through the cartridge, with one evaporating steps on a rotary evaporator andtwo eluting steps on the cartridge. n-hexane/acetone (2:1, v/v) was used for extraction and elutionin Procedure II with one evaporating step on a rotary evaporator and one eluting step on thecartridge. All extractions were performed under an ultrasonic bath and gas chromatography and massspectrometry were utilized for measurements. Procedure II was developed as a rapid, timesaving, lesscostly and safer substitute for Procedure I which was an old method. Procedure II was moreeffective for almost all the organophosphorus pesticides tested and 11of the 19 pyrethroidpesticides, while Procedure I was more appropriate for analysis of 5 pyrethroid pesticides. However,recoveries of most pyrethroid pesticides were fairly low. Thus, further studies should focus onadjustment and formulation of solvents for more efficient extraction and clean-up of pyrethroidpesticides from sediment samples.

Computational interaction analysis of organophosphorus pesticides with different metabolic proteins in humans

Pesticides have the potential to leave harmful effects on humans, animals, other living organisms, and the environment. Several human metabolic proteins inhibited after exposure to organophosphorus pesticides absorbed through the skin, inhalation, eyes and oral mucosa, are most important targets for this interaction study. The crystal structure of five different proteins, PDBIDs： 3LII, 3NXU, 4GTU, 2XJ1 and 1YXA in Homo sapiens （H. sapiens）, interact with organophosphorus pesticides at the molecular level. The 3-D structures were found to be of good quality and validated through PROCHECK, ERRAT and ProSA servers. The results show that the binding energy is maximum -45.21 relative units of cytochrome P450 protein with phosmet pesticide. In terms of H-bonding, methyl parathion and parathion with acetylcholinesterase protein, parathion, methylparathion and phosmet with protein kinase C show the highest interaction. We conclude that these organophosphorus pesticides are more toxic and inhibit enzymatic activity by interrupting the metabolic pathways in H. sapiens.

Enzyme Inhibition Rate Method for Rapid Detection of Organophosphorus and Carbamate Pesticides in Cowpea

[Objectives ] The paper was to explore enzyme inhibition rate method for rapid detection of organophosphorus and carbamate pesticides in cowpea. [ Methods ] Acetylcholinesterase （ACHE） was added to cowpea extract, to determine the inhibition rate of extract against enzyme. The influences of different sampiing methods and sampling parts on detection results were compared. [ Results] The positive rate of standard sampling was 18.18% higher than that of non-stand- ard sampling, and the positive rate of samples collected from cowpea tail was 16.67% higher than that collected from other parts. [ Condmions] Enzyme inhibi- tion rate method is suitable for rapid detection of organophosphorus and carbamate pesticides in cowpea.

Carboxylic Esterase and Its Associations With Long-term Effects of Organophosphorus Pesticides

To examine a） the effect of organophosphorus pesticide exposure on activity of carboxylic esterases, namely butyrylcholinesterase （BChE）, carboxylesterase （CarbE） and paraoxonase （PonE）; and b） the association of polymorphisms of BChE and PonE with individual genetic susceptibility to organophosphorus pesticide exposure. Methods A cross-sectional study was conducted in 75 workers exposed to organophosphorus pesticides and 100 non-exposed controls. The serum activity of these enzymes was measured. Variant forms of BCHE-K, PON-192, and PON-55 were detected. A symptom score was developed as a proxy measure of clinical outcomes. Results Activities of both BChE and CarbE were lower in exposed workers （27.3±21.65 runol.hl.mL^-l and 235.6±104.03 nmol-min^-l.mL^-l） than in non-exposed workers （78.313±30.354 nmol.h^-l.mL^-1 and 362.681_＋194.997 nmol.min^-1.mL^-1）. The activity of PonE was not associated with exposure status. The AChE activity in the exposed workers with BCHE-K genotype UU （61 cases）, genotype UK （12 cases） and genotype KK （2 cases） was 105.05, 84.42 and 79.00 mmol-h^-1.mL^-1, respectively and the accumulative symptom scores were 3.74, 9.17, and 12.50 accordingly. The AChE activity in the exposed workers with PON-192 genotype BB （37）, genotype AB （27） and genotype AA （11） was 116.8, 91.2, and 72,3 mmol-h^-1.mL^-1, respectively and the symptom scores were 2.00, 6.74, and 9.73 accordingly. The AChE activity in those with PON-55 genotype LL （70） and genotype LM （5） was 102.4 and 82.8 mmol-h^-1.mL^-1 and the symptom scores were 4.53 and 9.20. The symptom score was the highest in individuals with abnormal homozygote for each of the three gene loci. Condusions Long-term exposure to organophosphorus pesticides can inhibit BChE and CarbE activity, but exerts no inhibitory effect on PonE activity. Different genotypes of BCHE-K, PON-192, and PON-55 may be related to the severity of adverse health effects of organophosphorus pesticide exposure. Implications of potentially higher susceptibility of workers with mutant homozygotes should be evaluated to reduce health risks.

Application of Current Hapten in the Production of Broad Specificity Antibodies Against Organophosphorus Pesticides

Diethylphosphono acetic acid （DPA） was used as a current hapten to generate broad specificity polycolonal antibodies against a group of organophosphorus pesticides. Six New Zealand white rabbits were immunized with immunogens synthesized by the active ester method （AEM） or 1-ethyl-3-（3-dimethylaminopropyl）-carbodimide method （EDC）. The titers of antisera reached 25 600 by AEM and 6 400 by EDC, respectively. Polyclonal antibodies raised against DPA were screened and selected for the competitive indirect enzyme-linked immunosorbent assay （CI-ELISA）. A CI-ELISA for DPA was developed with a detection limit of 3.536 ng mL^-1and an I50 value of 0.182 μg mL^-1. The assay specificity was evaluated by obtaining competitive curves for several structurally related compounds as competitors. The antiserum showed high affinities to chlorpyrifos, diazinon, omethoate, parathion-ethyl and profenofos with I50 of 0.12, 0.15, 0.21, 0.88, 0.97 and 2.5 μg mL^-1, respectively. The results indicate that the assay could be a screening tool for quantitation and semiquantitation determination of the above former five organophosphorus pesticides.

Complete genome sequence of Bacillus amyloliquefaciens YP6, a plant growth rhizobacterium efficiently degrading a wide range of organophosphorus pesticides

Bacillus amyloliquefaciens YP6,a plant growth promoting rhizobacteria,is capable of efficiently degrading a wide range of organophosphorus pesticides(OPs).Here,we report the complete genome sequence of this bacterium with a genome size of 4009619 bp,4210 protein-coding genes and an average GC content of 45.9%.Based on the genome sequence,several genes previously described as being involved in solubilizing-phosphorus,OPs-degradation,indole-3-acetic acid(IAA)and siderophores synthesis.Interestingly,compared with the genomes of B.amyloliquefaciens species,strain YP6 had larger genome size and the most protein-coding genes.Moreover,the four categories of“cell envelope biogenesis,outer membrane(M),”“translation,ribosomal structure and biogenesis(J),”“transcription(K),”and“signal transduction mechanisms(T)”were fewer.These differences may be related to extensive environmental adaptability of the genus B.amyloliquefaciens.These results expand the application potential of strain YP6 for environmental bioremediation,provide gene resources involved in OPs degradation for biotechnology and gene engineering,and contribute to provide insights into the relationship between microorganism and living environment.

Spectroscopic Analysis of Organophosphorus Pesticides Using Colorimetric Reactions

The UV-Vis and infrared(IR)absorption spectra of organophosphorus(OP)pesticides have been studied.A correlation in spectra was developed to optimize the OP pesticides in the environments.The spectroscopic(UV-Vis and IR)spectrum of OP pesticides like methyl parathion,malathion and parathion has been interpreted in detail.A complete calculation of the normal frequencies and absolute intensities of UV-Vis and IR absorption bands are interpreted with the help of corresponding experimental data.In the colorimetric reactions,the bands appear at 2 077,1 637,1 455,1 015,655cm^(-1) for malathion;2 081,1 639,1 316,1 015,794,683cm^(-1) for parathion;2 078,1 632,1 032,794cm^(-1) for methyl parathion were used for quantitative or qualitative analysis.All these IR spectra were acquired by averaging 100 scans at a resolution of 4cm^(-1).It is determined experimentally in the region 200~450nm for UV-Vis absorption bands and in the region 400~4 000cm^(-1) for IR absorption bands.It is concluded that the mainly optically active groups(P—OH, C=O,P=O, C—O—C,P—O—C, P=S, —OH)present in pesticides which are responsible in change in significant data for quantitative and qualitative analysis.The various optical properties like wavelength,band energy,wave number,and frequency,also are calculated.

Multi-Residue Analysis of Organophosphorus Pesticides in Vegetable Using GC-MS

This study investigates the levels of pesticide residues in Cucumbers (Cucumis sativus), potatoes (Solanum tuberosum subsp. Tuberosum) and tomatoes (Lycopersicon esculentum). The samples were minced in a food processor initially subjected to extraction followed by cleanup using solid phase extraction (SPE) column. Separation was performed on a GC capillary column (Rtx-5 ms-30 m × 0.25 mm× 0.25 μm). The sample was injected by using splitless mode, helium as the carrier gas followed by quadrupole mass spectrometry detection. The mobile phase flow rates, column temperatures, and MS parameters were all optimized to reach high sensitivity and selectivity. Seven pesticides were detected in tomatoes sample, six in cucumber and four in potatoes samples. The findings indicate risks and concerns for public health.

The degradation of organophosphorus pesticides by means of sodium percarbonate

The factors and mechanisms of oxidative degradation of three organophosphorus pesticides （dichlorvos, methamidophos and phoxim） were studied with sodium percarbonate （SPC） as a solid oxidant. The result showed that SPC has highly activity in degrading these organophosphous pesticides. The most efficient degradation of pesticides occurred under basic conditions and the degradation rates increased with time extension and high temperature. The degradation of organophosphorus pesticides was expected to get even better results at lower initial concentration. Furthermore, we analyzed the intermediate products by NMP, spectrometry. On the basis of the analytical result, the oxidative degradation mechanism was proposed for each organophosphous pesticide. It is significant to understand the environment chemistry of organophosphorus pesticides in environmental system.

Separation of chlorinated hydrocarbons and organophosphorus, pyrethroid pesticides by silicagel fractionation chromatography and their simultaneous determination by GC-MS

A silicagel fractionation procedure for environmental sample extracts, which separates chlorinated hydrocarbons(CHCs) and organophosphorus, pyrethroid pesticides into two groups for subsequent instrumental analysis, was developed in this study. This method was achieved by optimizing the fraction cut-off volume of elution and different solvents. Using fully activated silica gel and cut-off CHCs collection after 10 ml 10% dichloromethane (DCM) in n-hexane passing through the column resulted in satisfactory separation of CHCs and organophosphorus, pyrethroid pesticides. This procedure had a higher reliability for CHCs than for organophosphorus, pyrethroid pesticides, because there is a relatively reliable recovery for CHCs. This approach is less expensive due to reducing sample pre-treatment time and solvent consumption.

Study of multiresidue analytical method for organonitrogen and organophosphorus pesticides in soil and water

A gas chromatographic method without derivatization was developed for the residue analysis of 10 organonitrogen and 9 organophosphorus pesticides in soil and water. The samples were blended or shaken with acetone for extraction. The extracts were cleaned up by coagulation, then, re-extracted with three 50 ml portions of dichloromethane. The final residue was detected by gas chromatography equipped with NPD. All of the 19 pesticides were completely separated at a constant temperature. The method described above was applicable to the simultaneous determination of 10 organonitrogen and 9 organophosphorus pesticides .in soil and water with the satisfactory recovery (from 82.42% to 103.57%), coefficient of variance (from 0.17% to 12.57%) and limit of detection (from 0.0006 ppm to 0.058 ppm).

Disposable Amperometric Acetylcholinesterase Biosensor for the Detection of Organophosphorus Pesticides

A rapid,simple,disposable and inexpensive acetylcholinesterase (ACHE) amperometric biosensor for the detection of organophosphorus pesticides was developed by simple adsorption of the enzyme on screen-printed electrodes.The biosensor consisted of an Ag/AgCl reference electrode and a graphite working electrode.The mixture of graphite and the 7,7,8,8-tetracyanoquinodimethane (TCNQ) was printed on electrodes.The detection of organophosphorus pesticides was done with acetylthiocholine chloride (ATCh) as substrate.The biosensor was used to detect the inhibitory effect of organophosphorus pesticides on AChE activity.The 1μl of enzyme solution containing 0.1 U AChE and 1% bovine serum albumin (BSA) were simply dropped on the working electrode surface.The biosensor operated at a potential of 300 mV vs. Ag/AgCl in a pH 7.2 0.1 mol/L phosphate buffer and 0.1 mol/L KCl.We obtained a calibration plot of the percentage inhibition versus the logarithm of parathion methyl concentration following an incubation time of 10 mix in parathion methyl solution. The lowest detectable amount of parathion methyl was 0.026 ppm.The amperometric biosensor based on acetylcholinesterase was disposable and low cost (about 1 yuan RMB).

Recent Advances in Degradation of Organophosphorus Pesticides

With the growing demand for environmental protection and physical health,food safety is now receiving more and more attention all over the world.However,pesticides are indispensable in agricultural production.Therefore,how to efficiently degrade pesticides and remove their residues in foods has always been a hot research topic in recent decades.This paper not only summarizes the types,degradation mechanism and artificial degradation of organophosphorus pesticides,but also highlights the latest advances in chemical degradation,photocatalytic degradation and biodegradation.

由乐果导致的重度急性有机磷中毒合并脓毒性休克的治疗体会

目的描述1例重度急性有机磷中毒(AOPP)合并复发性呼吸衰竭、中间综合征(IMS)、多器官功能障碍综合征(MODS)和脓毒症的诊断、治疗及临床病程。方法云南省第一人民医院内科重症监护病房(MICU)于2021年5月8日收治了1例自服农药乐果AOPP患者,经过29d的治疗痊愈出院。介绍临床诊治过程。结果患者男性,78岁,因自服农药乐果导致AOPP。入院后迅速出现呼吸衰竭,经紧急气管插管接呼吸机辅助呼吸,并进行一系列针对性治疗,包括应用复能剂碘解磷定、阿托品和山若碱,以及抗菌药物、维持水电解质和酸碱平衡等。在治疗过程中,患者病情经历了多次反复,如脓毒症发作、胆碱酯酶(ChE)水平大幅波动、多重耐药菌感染、呼吸衰竭反复出现等情况。最终,经过29d的治疗,患者成功脱离呼吸机,各器官功能恢复正常出院。结论通过对该病例的分析,提示在AOPP救治过程中需密切关注调整药物剂量,防治感染、脓毒性休克和呼吸机相关性肺炎(VAP)的发生,并及时心理评估和干预的重要性。

QuEChERS-气相色谱-三重四极杆串联质谱法测定玉米中7种有机磷农药

采用烘干玉米粉碎制样,优化了QuEChERS提取玉米中有机磷农药的方法,实现了经济快速提取玉米中有机磷农药残留,并建立了气相色谱-三重四极杆串联质谱对样品中有机磷农药进行定性定量检测。结果表明:7种有机磷农药的检出限(LOD)为0.03~0.49μg/kg,定量限(LOQ)为0.08~1.62μg/kg;方法精密度即相对标准偏差(RSD)为2.2%~16.7%,回收率为63.8%~122.3%。该方法具有简洁快速、回收率高、灵敏度高、抗基质干扰能力强的特点,适用于大批量玉米类作物中有机磷农药的痕量分析检测。

强化心理护理联合急救模式对有机磷农药中毒患者的影响

目的:分析强化心理护理联合急救模式对有机磷农药中毒的影响。方法:选取2021年3月—2023年3月滨州医学院附属医院收治的有机磷农药中毒患者72例作为研究对象,采取区组随机化法分组方式分为对照组(常规护理)、观察组(在对照组基础上给予强化心理护理联合急救模式),各36例。比较两组急救指标、转归指标、心理状态、家属满意度等。结果:观察组首次血液净化时间、留观时间短于对照组,抢救成功率高于对照组(P<0.05);观察组毒蕈碱样、烟碱样、中枢神经系统症状消失时间,胆碱酯酶恢复至60%时间及住院时间短于对照组(P<0.001);干预后,两组焦虑自评量表、抑郁自评量表评分低于干预前,观察组低于对照组(P<0.05);观察组服务态度、护理能力、配合协调性、急救及时性评分高于对照组(P<0.001);观察组并发症发生率低于对照组(P=0.024)。结论:针对有机磷农药中毒患者采取强化心理护理联合急救模式可获得较好的效果,可缩短急救时间,提高抢救成功率,减少并发症发生,调节心理应激水平,家属满意度较高。

有机磷农药中毒重症患者的呼吸衰竭急救措施及预后价值研究

分析急救措施对于有机磷农药中毒重症患者呼吸衰竭的影响以及预后价值。选取2022年1月—2023年1月贵港市人民医院收治的160例有机磷农药中毒重症患者进行研究,采用随机数字表法将患者分为对照组和救治组,每组各80例,对照组采用常规救治措施,救治组患者采用急救措施。比较两组患者的救治有效率、第一救治时长、血气分析指标、恢复情况以及并发症发生情况。结果显示,救治组患者救治总有效率高于对照组,第一救治时间短于对照组(P<0.05);救治后,救治组患者血氧分压高于对照组,动脉血二氧化碳分压低于对照组(P<0.05);救治组患者昏迷时长、下床活动时长、住院时长以及血胆碱酯酶上升时长均短于对照组(P<0.05);救治组患者并发症总发生率低于对照组(P<0.05)。研究发现,针对出现呼吸衰竭的有机磷农药中毒重症患者应及时采取急救措施抢救,以改善患者的临床症状。

一步式农药残留快速检测集成卡制备及应用

有机磷(OP)和氨基甲酸酯(CM)类农药的过量施用严重威胁人类的安全和健康,其检测受到复杂操作的限制。利用数字化控制的喷墨打印技术,并基于胆碱酯酶抑制法,构建了OP和CM类农药广谱、快速一步法检测方法。试验结果表明,该检测卡检测快速、灵敏度高、稳定性好和重复性高,适合多种场合实时检测,在即时检验(POCT)中表现出较大的应用潜力。