果蔬汁中有机磷农药残留能力验证结果与分析

为了监测实验室有机磷农药残留检测能力,参加全国范围内能力验证。该实验根据GB23200.116-2019国家标准,并对其方法进行简单优化。对于单一阳性样品,取两次平行检测的平均值,添加已知浓度的标准品,并计算回收率,减少基质效应对结果的影响。结果表明:有机磷农药残留能力验证结果满意,且实验室满足检测要求,确保了检测结果的可靠性;优化后,实验操作简单,可用于实验室日常快速检测有机磷类农药。

Toxic effects of acetochlor and methamidophos on earthworm Eisenia fetida in phaiozem, northeast China

Acetochlor and methamidophos are two important agrochemicals which are widely applied to agricultural production in northeast China. The investigation on the earthworm Eisenia fetida as an important type of soil animals exposed to single and binary-combined contamination of acetochlor and methamidophos was thus carried out. The single toxic effect test showed that the two agrochemicals had their toxicity to the earthworms living in phaiozem. Acetochlor had a stronger acute toxic effect on the earthworms than methamidophos. The mortality of the earthworms exposed to individual acetochlor and methamidophos changed with an increase in the exposure time and the exposed concentrations. The LD50 value of acetochlor and methamidophos toxic to the earthworms was 115.6-275,3 and 29.5-228.6 mg/kg, respectively. The weight of the earthworms was a more sensitive index compared to the mortality in indicating toxic effects of acetochlor and methamidophos in phaiozem. When considering both the mortality and the body-weight change, the combined pollution of acetochlor and methamidophos in phaiozem resulted in their synergic toxic effects on the earthworms.

Preparation of colloidal gold immunochromatography strip for detection of methamidophos residue

Methamidophos (Met) is a broad spectrum organophosphorus insecticide and acaricide.Even a trace of its residue is harmful to humans and many animals.In this study,the synthesis and identification of colloidal gold particles and antibody-colloidal gold conjugates were performed,and the preparation of colloidal gold immunochromatography strip was conducted for detection of Met residue.The size of colloidal gold particles was checked using a transmission electron microscope (TEM).The formation of antibody-coll...

Toxic effects of acetochlor, methamidophos and their combination on nifH gene in soil

Toxic effects of two agrochemicals on nifH gene in agricultural black soil were investigated using denaturing gradient gel electrophoresis （DGGE） and sequencing approaches in a microcosm experiment. Changes of soil nifH gene diversity and composition were examined following the application of acetochlor, methamidophos and their combination. Acetochlor reduced the nifH gene diversity （both in gene richness and diversity index values） and caused changes in the nifH gene composition. The effects of acetochlor on nifH gene were strengthened as the concentration of acetochlor increased. Cluster analysis of DGGE banding patterns showed that nifH gene composition which had been affected by low concentration of acetochlor （50 mg/kg） recovered firstly. Methamidophos reduced nifH gene richness that except at 4 weeks. The medium concentration of methamidophos （150 mg/kg） caused the most apparent changes in nifH gene diversity at the first week while the high concentration of methamidophos （250 mg/kg） produced prominent effects on nifH gene diversity in the following weeks. Cluster analysis showed that minimal changes of nifH gene composition were found at 1 week and maximal changes at 4 weeks. Toxic effects of acetochlor and methamidophos combination on nifH gene were also apparent. Different nifH genes （bands） responded differently to the impact of agrochemicals： four individual bands were eliminated by the application of the agrochemicals, five bands became predominant by the stimulation of the agrochemicals, and four bands showed strong resistance to the influence of the agrochemicals. Fifteen prominent bands were partially sequenced, yielding 15 different nifH sequences, which were used for phylogenetic reconstructions. All sequences were affiliated with the alpha- and beta-proteobacteria, showing higher similarity to eight different diazotrophic genera.

Isolation and Characterization of Penicillium oxalicum ZHJ6 for Biodegradation of Methamidophos

One methamidophos-degrading fungus strain, named as ZHJ6, was isolated from the soils contaminated with methamidophos. It was identified as Penicillium oxalicum based on its morphological characteristics and ITS rDNA gene sequence analysis. The effects of carbon source, nitrogen source and the concentration of methamidophos, temperature and pH on the degradation were investigated. The results showed that the strain could use glucose as carbon source and the methamidophos as sole nitrogen source. The degradation ratio of methamidophos, when the initial concentration was 1.0× 10^-3 mg mL^-1, could reach above 99.9% in 12 incubation days. The strain could use ethanol, glucose, fructose, sucrose, lactose, starch, and dextrin as its carbon and energy source to degrade the methamidophos. The favorable degrading condition of the strain ZHJ6 was in a mineral salt medium at pH 5.0 and 25℃ with 1% glucose, and further studies showed that the strain could degrade folimat, phoxim and glyphosate with glucose as carbon source, but could not degrade chlorpyrifos, phosdrin, trichlorphon, and dichlorvos.

Effect of methamidophos on soil fungi community in microcosms by plate count,DGGE and clone library analysis

Methamidophos was widely used a pesticide in northern China. The potential influences of methamidophos on soil fungal community in black soil were assessed by plate count, 28S rDNA-PCR-DGGE, and clone library analysis. Three methamidophos levels （50, 150, and 250 mg/kg） were tested in soil microcosms. Results from plate count during a 60-d microcosm experiment showed that high concentrations of methamidophos （250 mg/kg） could significantly stimulate fungal populations. DGGE （denaturing gradient gel electrophoresis） fingerprinting patterns showed a significant difference between the responses of culturable and total fungi communities under the stress of methamidophos. Shannon diversity indices calculated from DGGE profiles indicated that culturable fungi in all microcosms with methamidophos treatment increased after 1 week of incubation. However, the diversity indices of total fungi decreased in the first week, as compared to the stimulation of culturable fungi. At the 8th week, however, all the microcosms treated by methamidophos were similar to the control microcosms in community structure as suggested by the Shannon diversity indices for both culturable and total fungi. In contrast, after 1 week the fungal structure of culturable and unculturable both were disturbed to different extent under the stresses of methamidophos by clustering analysis. Clone sequencing analysis indicated the stimulation of pathogenic and unculturable fungal populations by methamidophos treatment, suggetsing potential risks of plant disease outbreak.

Studies on Purification of Methamidophos Monoclonal Antibodies and Comparative Immunoactivity of Purified Antibodies

To purify Methamidophos (Met) monoclonal antibodies with two methods and compare immune activity of purified antibodies. Method Caprylic acid ammonium sulphate precipition (CAASP) method and Sepharose protein-A (SPA) affinity chromatography method were used to purify Met monoclonal antibodies, UV spectrum scanning was used to determine protein content and recovery of purified antibodies, sodium dodecylsulphate polyacrylamide gel electrophoresis (SDS-PAGE) was used to analyze the purity of purified antibodies, and enzyme-linked immunosorbent assay (ELISA) was used to determine immune activity of purified antibodies. Results Antibody protein content and recovery rate with CAASP method were 7.62 mg/mL and 8.05% respectively, antibody protein content and recovery rate with SPA method were 6.45 mg/mL and 5.52% respectively. Purity of antibodies purified by SPA method was higher than that by CAASP method. The half-maximal inhibition concentration (IC50) of antibodies purified by SPA to Met was 181.26 靏/mL, and the linear working range and the limit of quantification (LOD) were 2.43-3896.01 靏/mL and 1.03 靏/mL, respectively. The IC50 of antibodies purified by CAASP to Met was 352.82 靏/mL, and the linear working range and LOD were 10.91-11412.29 靏/mL and 3.42 靏/mL, respectively. Conclusion Antibodies purified by SPA method are better than those by CAASP method, and Met monoclonal antibodies purified by SPA method can be used to prepare gold-labelled testing paper for analyzing Met residue in vegetable and drink water.

Effects of Acetochlor and Methamidophos on Fungal Communities in Black Soils

Using plate counting and ergosterol assay, single and joint effects of acetochlor and methamidophos on the dynamicsof soil fungal population and total fungal biomass in the black soil zone of Northeast China were investigated. The resultsdemonstrated that acetochlor at high concentration levels (150 and 250 mg kg-1) had an acute and mostly chronic toxicityon both the soil fungal population and total fungal biomass, but at a low concentration (50 mg kg-1) generally had astimulating effect that was stronger with total fungal biomass than with the soil fungal population. Methamidophos ata high concentration level (250 mg kg-1) alone and almost all of its combinations with various dosages of acetochlorincreased the soil fungal population, whereas at most sampling dates with 250 mg methamidophos kg-1 soil, total fungalbiomass increased, but in combination with acetochlor it was decreased in the early period of incubation and then increased28 days after incubation. Thus, through measuring the number of colony forming unit of the soil fungal population alongwith the total fungal biomass, a better understanding on effects of agrochemicals on soil fungi could be made.

Joint toxicity of methamidophos and cadmium acting on Abelmoschus manihot

Joint toxicity of methamidophos and cadmium(Cd) on the ornamental Abelmoschus manihot was firstly examined and compared with single-factor effects of the two pollutants using ecotoxicological indexes including the inhibitory rate of seed germination, root elongation and inhibitory concentration 50%(IC_ 50). The results indicated that methamidophos and Cd had unobvious(p>0.05) effects on seed germination of the ornamental. There were significant(p<0.05) inhibitory effects of Cd on root elongation of the tested plant. When the concentration of added Cd was low(<20 mg/L), significant antagonistic effects on root elongation were observed. And synergic effects were observed when Cd was added in high dose(>20 mg/L). However, the analysis of joint effects indicated that there were antagonistic effects between Cd and methamidophos under all the treatments. At the high concentration of Cd, joint toxicity of methamidophos and Cd was more dependent on concentration of Cd.

Relationship Between the Development of Methamidophos Resistance and the Activities of Three Detoxifying Enzymes in Brown Planthopper, Nilaparvata lugens

Methamidophos resistance of brown planthopper(BPH), Nilaparvata lugens was selected in laboratory for 19 generations (F1 to F19). The resistance development in BPH was approximatively shaped as the letter 'S' : resistance change was small before the fifth generation and after the fifteenth generation, and the changing pattern was sharp between the fifth and the fifteenth generation. Esterase might play an important role in the resistance development, because the esterase activity and the number of individuals with high activities increased along with the resistance development. The esterase activities of insecticide-sensitive population S, field population F0, its selective generations F5, F10 and F15 were highly correlated with the resistance ratios of these generations, and the coefficient was 0.9899. Mixed-function oxidases and glutathione S-transferase also might play some roles in the resistance development, but the big change in the activities of the two detoxifying enzymes both took place before the tenth generation.

The genotoxic effects of benzo[a]pyrene and methamidophos on black porgy evaluated by comet assay

In this study, two common pollutants (benzo[a]pyrene and methamidophos) in marine environment were tested by comet assay for their inducement of in vivo genotoxic effect to the blood cells of black porgy ( Acanthopagrus schlegeli). The fish was exposed to 2 μg/L of benzo[a]pyrene (BaP) and methamidophos, and their mixture. The assay was performed on whole blood at 2 h, 5 h, 24 h and 96 h exposure intervals. A signifi- cant increase in DNA damage was observed in each treatment with the pollutants. Additive effect of BaP and methamidophos was also found in the experiment. However, the decrease ratios of DNA damage for 5 h and 96 h exposure interals compared with 2 h and 24 h exposure ones, respectively, were noticed. This phenomenon may be explained by the function of repairing process via enzyme cytochrome P450 in the animal. Evidence of the genotoxicity of organophosphorus pesticides (OPs) and polynuclear aromatic hydrocarbons (PAHs) on marine fish are discussed in this paper.

苯线磷和甲胺磷对TF-1细胞乙酰胆碱酯酶影响的差异

有机磷农药(organophosphorus pesticides,OPs)具有较强的神经毒性,主要是通过抑制胆碱能神经传导中的关键酶,乙酰胆碱酯酶(acetylcholinesterase,AChE,EC 3.1.1.7)的活性来实现的。苯线磷和甲胺磷是广泛用于农业生产的OPs,但对它们抑制人AChE活性的机制研究十分有限。本研究应用2种不同的给药方式,包括对培养的细胞和细胞裂解液进行药物处理,明确苯线磷和甲胺磷对人血液白血病细胞系TF-1中AChE酶活性的直接作用和对AChE基因转录表达的影响,从而揭示苯线磷和甲胺磷抑制AChE酶活性的机制与两者的差别。结果表明,高浓度苯线磷(10^(-3) mol·L^(-1))处理后,TF-1细胞活力降低,同时诱导细胞凋亡和坏死;而所有被试浓度的甲胺磷对细胞活力均没有明显影响。此外,对于TF-1细胞裂解液中的AChE,苯线磷和甲胺磷短期处理(1 h和5 h)均可产生直接抑制作用,其中苯线磷的抑制作用略强于甲胺磷(孵育1 h,IC_(50)值分别为1.181×10^(-6) mol·L^(-1)和2.837×10^(-6) mol·L^(-1))。对培养细胞的药物处理实验结果显示,苯线磷和甲胺磷(10^(-6) mol·L^(-1)和10-5 mol·L^(-1))处理24 h后,均显著降低了TF-1细胞的AChE酶活性,苯线磷的抑制率略高于甲胺磷。而与对酶活性的抑制作用相反,苯线磷和甲胺磷对TF-1中AChE H转录本表达有轻微的上调作用,以甲胺磷更为明显,提示存在反馈调节机制。总结上述结果,我们发现苯线磷对TF-1细胞中AChE的抑制作用总体略强于甲胺磷,而甲胺磷对AChE基因表达的反馈上调作用更明显。从而首次从对AChE酶的直接抑制作用和生物合成影响的不同角度阐述了2个OPs对AChE影响的差异,为进一步的分子机制研究提供了实验数据。

固相萃取-气相色谱法测定水中甲胺磷

建立固相萃取-气相色谱法测定水中甲胺磷的方法。以甲醇为洗脱剂,采用椰壳活性炭固相萃取柱对水样富集,将洗脱液氮吹至近干,然后用乙酸乙酯定容至1 mL,采用气相色谱火焰热离子检测器(FTD)检测。甲胺磷的质量浓度在0.1~1.0 mg/L范围内与色谱峰面积线性关系良好,相关系数为0.998,甲胺磷的检出限为0.0001 mg/L,定量限为0.0004 mg/L。采用所建方法对实际水样进行测定,地表水和自来水样品加标回收率分别为83.2%~90.8%、87.8%~98.8%,测定结果的相对标准偏差分别为5.5%~8.3%、7.7%~10%(n=6)。该方法操作简单、有机溶剂用量小,可用于生活饮用水及水源水中甲胺磷的测定。

基于QuEChERS-超临界流体色谱-串联质谱法的茶叶中甲胺磷及乙酰甲胺磷对映体拆分及定量

采用QuEChERS法提取,在以Chiral-Pak IC-3为色谱柱的超临界流体色谱上拆分,大气压化学电离后串联四极杆质谱法测定。结果表明,茶叶中(+)-甲胺磷、(+)-乙酰甲胺磷的检出限为5μg/kg,定量限为10μg/kg,平均回收率为70.53%~110.61%,相对标准偏差(RSD)为2.92%~13.30%。该方法能够有效拆分和定量甲胺磷和乙酰甲胺磷对映异构体。

不同水浴温度对蔬菜中甲胺磷回收率的影响

文章探究了甲胺磷在净化过程中水浴温度对回收率的影响。以生菜为样品,在净化过程中分别在80℃、65℃、55℃、45℃水浴锅上加热吹干,对比甲胺磷回收率。甲胺磷在水浴温度45℃时回收率最高。热稳定性较差的有机磷农药,在样品前处理的净化过程中,可适当降低水浴温度,提高回收率,增加实验的准确性。

曲霉M—2降解有机磷农药(甲胺磷)的研究

分离了一株能降解甲胺磷的曲霉Ｍ－２。Ｍ－２能以甲胺磷为唯一碳源、氮源及磷源生长。在０．２％甲胺磷无机盐发酵液中，培养５ｄ后，降解率达８１．５％。添加少量有机氮能促进Ｍ－２对甲胺磷的利用。

兔抗甲胺磷多克隆抗体的制备

采用水溶性碳化二亚胺法 (EDC) ,将MTP与牛血清蛋白 (BSA)、人血清蛋白 (HSA)和鸡卵清蛋白(OVA)共价偶联 ,分别合成免疫抗原MTP BSA、MTP HSA和包被抗原甲胺磷 鸡卵清蛋白 (MTP OVA) ,用合成的免疫抗原对新西兰大白兔进行免疫 ,制得抗血清经鉴定确证为兔抗MTP多克隆抗体 (polyclonalantibody ,PAB) ,效价分别为 1∶15 0 0 0和 1∶12 0 0 0。

甲胺磷人工抗原的合成和鉴定(英文)

目的 合成和鉴定甲胺磷人工抗原。方法 用磷酸化方法偶联氧、硫二甲基硫代磷酚氯到牛血清蛋白上,然后做一系列的实验,如:测定磷、紫外、31P核磁共振光谱和兔疫小鼠等。结果 人工抗原的偶联比是16,人工抗原的紫外光谱图与牛血清蛋白质相比发生改变,人工抗原和标准甲胺磷的31P核磁共振光谱具有相同的化学位移峰,被免疫的小鼠产生了抗甲胺磷的抗体。结论 甲胺磷人工抗原合成成功,为其免疫测定方法的建立提供了条件。

复合纳米Fe_2O_3/TiO_2的制备、表征及光催化活性

采用将TiO2 加入Fe(OH ) 3 胶体中的方法制得复合的Fe2 O3 /TiO2 纳米粒子 .以光催化降解甲胺磷研究其光催化活性 ,并通过XRD、TEM、DRS等分析方法 ,探讨了影响其光催化活性的原因 .结果表明 ,Fe2 O3 的复合量对Fe2 O3 /TiO2 的活性影响很大 ,当n(Fe)∶n(Ti) <0 .3%时 ,复合物Fe2 O3 /TiO2 的光催化活性大于TiO2 ,最佳的复合量为0 .2 % .当复合量大于 0 .5 %时 ,复合物Fe2 O3 /TiO2 的光催化活性低于TiO2 .锻烧温度及锻烧时间对复合物Fe2 O3 /TiO2 光催化活性均有影响 .用XRD确定掺杂前后TiO2 的晶型均为锐钛矿型 ,当复合量大于 0 .7%时才能看到Fe2 O3 的衍射峰 .TEM照片表明 ,由于复合量小 ,复合前后颗粒直径和晶粒直径基本一致 .反射率光谱图表明 ,在 36 0～ 6 5 0nm范围内复合物Fe2 O3 /TiO2 吸收光的性能比TiO2 好 。

乙酰甲胺磷及其高毒代谢物甲胺磷在白菜中的残留动态

为明确乙酰甲胺磷在叶菜类蔬菜上使用后的环境安全性,采用气相色谱法比较研究了露地与设施栽培条件下乙酰甲胺磷及其高毒代谢物甲胺磷在白菜中的残留动态规律和最终残留。结果表明,按推荐使用剂量、2倍推荐使用剂量施药1次,乙酰甲胺磷在白菜中降解半衰期为2.060～3.203 d,大棚条件下降解速度慢于露地条件下降解速度;乙酰甲胺磷在降解过程中可代谢产生甲胺磷,作物中甲胺磷的残留量是乙酰甲胺磷代谢生成和甲胺磷本身降解两个过程共同作用的结果,施药几天后,出现一个甲胺磷残留的高峰;乙酰甲胺磷施用在白菜上可能会有较高的甲胺磷残留风险,尤其是大棚栽培方式、施药浓度高的情况下使用乙酰甲胺磷具有更高的甲胺磷残留风险。因此,在白菜等叶菜类蔬菜上应谨慎使用乙酰甲胺磷,露地栽培条件下的安全间隔期应延长为21 d,设施栽培条件下不宜使用。