Lei Yu, Mulchandani Priti, Chen Wilfred, Mulchandani Ashok
Department of Chemical and Environmental Engineering, University of California, Riverside, CA 92521, USA.
J Agric Food Chem. 2005 Feb 9;53(3):524-7. doi: 10.1021/jf048943t.
A microbial biosensor for rapid, sensitive, selective, and cost-effective determination of the total content of organophosphorus nerve agents with p-nitrophenyl substituent is reported. The biosensor consisted of genetically engineered PNP-degrader Pseudomonas putida JS444 expressing organophosphorus hydrolase (OPH) on its cell surface immobilized on a dissolved oxygen electrode. Surface-expressed OPH catalyzed the hydrolysis of organophosphorus pesticides with p-nitrophenyl substituent such as paraoxon, methyl parathion, and parathion to release p-nitrophenol that was oxidized by the enzymatic machinery of Pseudomonas putida JS444 to carbon dioxide while consuming oxygen. The oxygen consumption was measured and correlated to the concentration of organophosphates. The sensor signal and response time were optimized with 0.086 mg dry weight of cell and operating in 50 mM pH 7.5 citrate-phosphate buffer with 50 microM CoCl(2) at room temperature. When operated at optimized conditions, the biosensor measured as low as 55 ppb of paraoxon, 53 ppb of methyl parathion, and 58 ppb of parathion without interference from most phenolic compounds and other commonly used pesticides, such as atrazine, coumaphos, sutan, sevin, and diazinon. The operational life of the microbial biosensor was approximately 5 days when stored in the operating buffer at 4 degrees C.
报道了一种用于快速、灵敏、选择性且经济高效地测定具有对硝基苯基取代基的有机磷神经毒剂总含量的微生物生物传感器。该生物传感器由基因工程改造的PNP降解菌恶臭假单胞菌JS444组成，其在固定于溶解氧电极上的细胞表面表达有机磷水解酶（OPH）。表面表达的OPH催化具有对硝基苯基取代基的有机磷农药（如对氧磷、甲基对硫磷和对硫磷）水解，释放出对硝基苯酚，该对硝基苯酚被恶臭假单胞菌JS444的酶促机制氧化为二氧化碳，同时消耗氧气。测量氧气消耗量并将其与有机磷酸盐的浓度相关联。在室温下，使用0.086 mg干重的细胞，并在含有50 μM CoCl₂的50 mM pH 7.5柠檬酸盐 - 磷酸盐缓冲液中操作，对传感器信号和响应时间进行了优化。在优化条件下操作时，该生物传感器可检测低至55 ppb的对氧磷、53 ppb的甲基对硫磷和58 ppb的对硫磷，不受大多数酚类化合物和其他常用农药（如阿特拉津、蝇毒磷、苏旦、西维因和二嗪农）的干扰。当在4℃下保存在操作缓冲液中时，该微生物生物传感器的使用寿命约为5天。
