| Organophosphorus pesticides (OPs) have characteristics of insecticidal resilient and a wide range of applications and become one of the most wide insecticides that used in Agriculture,Pesticide using in the process,with the precipitation and irrigation water in the surface they can run off into rivers and lakes,and eventually into the ocean.Therefore,the rapid development of sensitive detection technique is very necessary.Biomarker owing to the production of low cost,high speed analysis of the advantages,in the marine OPs automatic,continuous,on-line measurement has an important value,much attention.At present,biomarkers such as cholinesterase in animals commonly used to describe the environment OPs pollution levels.However,inshore water often contain more than one of the OPs,activity changes of biomarkers reflect the total amount of pesticides and could not explain the existence of a certain kind of OPs in the environment.To this end,correctly identify the type of OPs in the seawater is particularly important.Different biological sources of cholinesterase put up differences sensitivity to OPs, this study uses three different sources of cholinesterase (AChE from Electrophorus electricus and Scomberomorus niphonius,BChE from Horse serum) as biomarkers and compares the sensitivities of them to malathion,methyl-parathion and chlorpyrifos,The results show that the sensitivities of AChE from Scomberomorus niphonius to chlorpyrifos and methyl-parathion have no indiscrimination,but stronger than the sensitivities to malathion;the sensitivities of AChE from Electrophorus electricus to methyl-parathion and malathion are stronger than chlorpyrifos,but not much below;the sensitivities of BChE to three OPs are weaker.The extent of cholinesterase response to the OPs is affected by many non-biological factor (the water pH, inhibition of time, temperature, etc).In this study, seawater as the matrix,oxidates methyl parathion and malathion with sodium hypochlorite (NaClO) to enhance its effect on the BChE from horse serum,optimizes the conditions of three biomakers response to the different of OPs,the greatest reaction conditions of AChE from Electrophorus electricus and Scomberomorus niphoniu response to the three pesticides are as flows:Temperature is 35~37℃,pH value is 7 to 8,the reaction time is at least 30min. For the BChE from horse serum,the best pH of pre-oxidation of the two OPs is 6,an for chlorpyrifos that don't oxidate,the best pH value is 7,temperature is 35~37℃, the reaction time is at least 30min.On this basis,the election of the three conditions are suitable (pH=7; Temperature: 35℃;time: 30 min),under the same conditions,studies on the response of three ChE to the single OPs in the seawater.When the concentration of pesticides is from 10 to 500μg/L,the activity inhibition rate of the three cholinesterase increase with the concentration of pesticides increased,but the response existences are different.Thus,find the typical characteristics suitable for recognition the OPs,only methyl- parathion and malathion concentration of less than 100μg/L,chlorpyrifos concentrations is in the 300~350μg/L, because three of the inhibition rate of the activity was not significantly different,so unable to identify by the response.Other scope of concentrations can select the appropriate biomarkers to identify the OPs.Through the establishment line of a single type of OPs identification, using the simulation seawater sample that contains a single OPs, test the effectiveness of the identification method,the correct identification rate is 73.3.In short,using a variety of biomarkers of response can identify a single OPs in the seawater rapidly,and has a high rate of correct identification,biomarkers is expected to be a simple,efficient means to identify OPs qualitatively in the seawater.
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