Study on Immunochemical Assays for the Organophosphorus Insecticide Chlorpyrifos

The anti-chlorpyrifos polyclonal antibodies were obtained by using the artificial immune antigen to immune in New Zealand′s white rabbits. The enzyme-tagged antibodies were prepared by coupling horseradish peroxidase (HRP) to the purified antibody with the modified sodium periodate method. The indirect competitive enzyme linked immuno-sorbent assays (ELISA) and the HRP-taggedantibodydirect ELISA (E-Ab) were established, respectively.The limit of detection (LOD) for the indirect ELISA and E-Ab were 0.0033 and 0.0042 μg mL-1, respectively. The linear detection ranged well from 0.005 to 2.0 μg mL-1.     

Development of the Artificial Antigens for the Organophosphorus Insecticide chlorpyrifos

This study reported that the hapten of the organophosphorus insecticide chlorpyrifos,O,Odiethyl-O-[3,5-dichloro-6-(2-carboxyethyl)thio-2-pyridyl]phosphorothioate(named AR) was synthesized by using technical grade chlorpyrifos reacted with 3-marcapropanoic acid in hot alkaline solution.The hapten was conjugated to bovine serum albumin (BSA) with the modified active ester method to form artificial immune antigen.The ratio of AR:BSA was 39:1.The artificial coating antigen for chlorpyrifos was synthesized by conjugating AR to ovalbumin (OVA) with the mixed-anhydride method,and the ratio was 13:1.The anti-chlorpyrifos polyclonal antibodies were obtained by using the artificial immune antigen (AR-BSA) to immune in the rabbits.     

Chlorpyrifos-induced oxidative stress and histological changes in retinas and kidney in rats: Protective role of ascorbic acid and alpha tocopherol

This study was undertaken to evaluate the antioxidant effect of vitamins C and E against oxidative stress, apoptosis and histological changes of kidney and retina in CPF-treated rats. Forty male Sprague-Dawley rats were divided into four groups including the control group, the group treated orally with a single dose of CPF (63 mg/kg b.w.), the group injected intramuscularly (i.m.) with vitamin C (250 mg/kg b.w.), and intraperitonealy (i.p.) with vitamin E (150 mg/kg b.w.) daily for 7 days and the group treated with CPF (single dose) and injected with vitamins (for 7 days). The results showed that CPF induced apoptosis and severe oxidative stress as indicated by the significant increase in MDA and sFasL concentration and the significant decrease in GSH concentration in serum. Co-administration of vitamins C and E ameliorate these toxic effects and improved the histological pictures of kidneys and retinas. It could be concluded that combined administration of vitamins C and E is useful in the routine therapy for the protection against tissue damage induced by CPF.     

25%毒·唑磷乳油防治稻纵卷叶螟药效试验

为探索常规杀虫剂防治稻纵卷叶螟效果下降的替代农药,采用25%毒.唑磷乳油进行了田间药效试验。结果表明,25%毒.唑磷乳油防治稻纵卷叶螟虽然速效性不够理想,但具有持效期长、对2~3龄幼虫防治效果较好的特点,在稻纵卷叶螟偏重发生时,可达到理想的防治效果。未发现25%毒.唑磷乳油对水稻产生毒副作用,因此,是防治稻纵卷叶螟较理想的药剂。     

Effect of spray volume of two organophosphate pesticides on coverage and on mortality of California red scale Aonidiella aurantii (Maskell)

A trial under laboratory conditions was carried out to study the possibility of decreasing the delivered dose of organophosphate insecticides without affecting their efficacy against California red scale (CRS), Aonidiella aurantii (Maskell), by reducing the volume of water used whilst maintaining the concentration of pesticide. In order to establish an optimal application volume, the coverage and the efficacy against different stages of development of CRS of two commercial organophosphate pesticides (chlorpyrifos 750 g kg⁻¹ WG [Dursban^® 75 WG] and chlorpyrifos-methyl 224 g l⁻¹ EC [Reldan^® E]) at four volumes of water (1, 2, 3 and 4 ml) were compared. Results showed that in general Chlorpyrifos-methyl-based product (CMBP) provided greater coverage and impact size, but did not achieve the highest efficacy. The minimum-deposited volume (1.01 μl/cm²) produced 11% coverage with Chlorpyrifos-based product (CBP) and 22% with CMBP, reaching the highest efficacies (around 89-95%) against the youngest stages (N1 and N2 stages) with both products. To attain similar efficacy with males (prepupal and pupa stages), twice the volume (2.03 μl/cm²) of the CBP was required, producing 28% coverage. The CMBP required higher deposited volumes (3.41 μl/cm²) and higher coverage (51%). The maximum efficacy in the control of adult females (third instar and gravid female stages) was 70% with both pesticides. This level was attained with 3.41 μl/cm² of CBP (36% coverage) and 4.72 μl/cm² of CMBP (62% coverage). The research shows that greater coverage does not result in greater efficacy, so it would be possible to reduce the spray volume in field conditions. Further research will be carried out in order to check these results under real field conditions.     

重离子诱变鞘氨醇单胞菌选育毒死蜱高效降解菌株及应用

从青藏高原牦牛粪中分离出1株可降解毒死蜱的细菌,经形态和16SrDNA序列分析,鉴定其为鞘氨醇单胞菌属(Sphingomonas sp.)细菌。对其进行重离子诱变并筛选出菌株Sph-25-T1,该菌株对100mg.L-1毒死蜱的72h降解率达98.44%,比出发菌株提高27.37%。对Sph-25-T1进行传代培养,第5代时其对毒死蜱的降解率依然保持在90%以上。以喷洒毒死蜱1周后的不同土壤浸出液或蔬菜叶片做培养基时,Sph-25-T1对毒死蜱的降解率达到29.68%～78.40%。     

两株蜡状芽孢杆菌对毒死蜱的降解动力学研究

利用微生物消除农药污染是一项安全、经济、有效的方法,降解动力学模型的构建有助于理解污染物的生物降解行为和估测系统中特征污染物的浓度变化,菌株对高浓度污染物的降解效果是降解菌在受污染水体中实际应用的关键。本研究采用基础培养基中定量添加毒死蜱和定时取样分析毒死蜱残留浓度的方法,探讨两株蜡状芽孢杆菌(HY-1和HY-2)的接种体培养时间、接种量和降解菌对毒死蜱的降解动力学,同时研究了降解菌对高浓度毒死蜱的降解率。结果表明:HY-1和HY-2最适接种体培养时间分别为10 h和19 h,接种体培养时间对菌株降解毒死蜱的影响较大。两菌株最适接菌量为8%(v/v),接种量从4%增至8%时,接种量对HY-1降解毒死蜱的影响大于HY-2。当毒死蜱的初始浓度为40 mg.L 1、80 mg.L 1、100 mg.L 1和120 mg.L 1时,一级动力学方程ln(C0/Ct)=kt可以用来拟合两菌株对毒死蜱的降解动力学及确定降解动力学参数,当毒死蜱初始浓度再次增加时,仅HY-2对毒死蜱的降解符合一级动力学方程。当毒死蜱初始浓度为40~120 mg.L 1时,菌株HY-1对毒死蜱的降解速率常数分布在0.013 5~0.015 7;当毒死蜱初始浓度为40~200 mg.L 1时,菌株HY-2的降解速率常数分布在0.008 0~0.015 3。菌株HY-2比HY-1可以在较高的毒死蜱浓度下发挥降解作用,且降解率较高。因此,两菌株在毒死蜱污染水体的净化去毒方面具有重要意义。     

毒死蜱不同施药方式对黄曲条跳甲的敏感性检测

本实验以黄曲条跳甲为试虫,以毒死蜱和啶虫脒为实验药剂,分别采用浸叶法和浸虫法测定了毒死蜱和啶虫脒单剂及相关混配对黄曲条跳甲的毒力。试验结果显示,毒死蜱和啶虫脒对黄曲条跳甲的浸叶LC50值分别为53．81、268．03mg／L。啶虫脒和毒死蜱按浓度比1：4混配、1：8混配浸叶LC50值分别为58．14、41．71mg／L,浸虫法结果显示啶虫脒和毒死蜱按浓度比1：4混配、1：8混配稀释4000倍液校正死亡率分别为23．3％、26．7％。     

储藏和加工方式对稻谷中毒死蜱和三唑磷残留量的影响

[目的]了解稻谷加工方式和储藏方式对稻米中毒死蜱和三唑磷残留动态的影响机制。[方法]采用液相色谱-三重四极杆质谱法同时检测稻米中的毒死蜱及其代谢物3,5,6-三氯-2-吡啶酚(3,5,6-Trichloro-2-pyridinol,TCP)和三唑磷残留,分析碾磨、蒸煮、发芽加工以及储藏温度(37和4℃)对毒死蜱和三唑磷残留量的影响。[结果]毒死蜱及其代谢物TCP、三唑磷等农药残留多数分布在米糠层;短时间的蒸煮无法明显降低稻谷中毒死蜱的残留量;发芽稻谷中毒死蜱及其代谢物TCP、三唑磷的残留量显著低于未发芽稻谷;在37℃储藏条件下,毒死蜱的降解方程为C=0.899e~(-0.005t)(R~2=0.855 6),半衰期为138.6 d;三唑磷降解方程C=0.768e-0.009t(R~2=0.822 8),半衰期77.0 d,近似满足一级动力学模型方程;在4℃低温储藏条件下,稻谷中毒死蜱和三唑磷的残留量变化不大。[结论]碾磨和发芽加工有利于降低稻谷的农药残留量,低温储藏稻谷不利于残留农药的降解。研究可为稻米加工过程的风险评估以及开发稻米中农药残留的消解技术提供参考。     

毒死蜱降解菌的筛选及其特性的研究

［目的］筛选对毒死蜱具有良好降解作用的菌株,为利用微生物进行有机磷农药土壤修复提供理论依据。［方法］采用富集分离法从喷施毒死蜱的土壤中分离出4株对毒死蜱有良好降解作用的菌株,经复筛最终得到1株能够高效降解毒死蜱农药的微生物菌株D12,在充分供氧的条件下,研究菌株降解毒死蜱的降解过程、生长条件及其影响因素,并在纯培养的条件下测定该菌株对毒死蜱的降解效果。［结果］当接种量为菌浓度OD560=0.179,最适pH值为7.0,温度为30 ℃,毒死蜱浓度为100 mg/L时,该菌株D12培养6 d后的降解率达到50.4％。该菌生长的最佳毒死蜱浓度为1000 mg/L,对毒死蜱的最大耐受浓度为3 000 mg/L。［结论］试验筛选的菌株D12在基础培养基中对毒死蜱有较强的降解能力。