A dehydrochlorinase-based pH change assay for determination of DDT in sprayed surfaces

Morou, Evangelia, Ismail, Hanafy ORCID: https://orcid.org/0000-0002-9953-9588, Dowd, Andrew, Hemingway, Janet ORCID: https://orcid.org/0000-0002-3200-7173, Labrou, Nikos, Paine, Mark ORCID: https://orcid.org/0000-0003-2061-7713 and Vontas, John (2008) 'A dehydrochlorinase-based pH change assay for determination of DDT in sprayed surfaces'. Analytical Biochemistry, Vol 378, Issue 1, pp. 60-64.

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Abstract

A glutathione S-transferase (GST) from the mosquito Aedes aegypti (aagste2), selected in the field as a major metabolic resistance enzyme for this parasite vector, was employed to produce a highly specific assay for the determination of DDT [1,1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene]. Detection is based on the pH change occurring in an appropriate buffer system by the concomitant release of H+ during the aagste2-catalyzed dehydrochlorination reaction and is monitored potentiometrically or colorimetrically in the presence of a pH marker. The theoretical limit of detection (LOD) of the assay is 3.8 mu g/ml, and the linear range of quantification is 12 to 250 mu g/ml. The method does not recognize biologically inactive DDT analogues or major DDT photodegradants and breakdown molecules, and it is highly specific for the insecticidal p.p'DDT [1,1,1-trichloro-2,2-bis(p-chlorophenyl) ethane]. The biosensor was validated with a number of insecticide swabs from DDT-sprayed surfaces and found to be reproducible and reliable as compared with high-performance liquid chromatography (HPLC) (correlation coefficient R-2 = 0.98). Given the current expansion of DDT residual sprayings in many regions of Africa as a key strategic intervention for malaria vector control, this simple assay to monitor DDT levels for vector control spraying programs could have an important impact on malaria control. (c) 2008 Elsevier Inc. All rights reserved.

Item Type:	Article
Uncontrolled Keywords:	potentiometer malaria vector control biosensor hplc insecticide glutathione-s-transferase substrate-specificity quantification pesticides resistance biosensor vector
Subjects:	QX Parasitology > Insects. Other Parasites > QX 510 Mosquitoes QX Parasitology > Insects. Other Parasites > QX 600 Insect control. Tick control QX Parasitology > Insects. Other Parasites > QX 525 Aedes
Faculty: Department:	Groups (2002 - 2012) > Vector Group
Digital Object Identifer (DOI):	https://doi.org/10.1016/j.ab.2008.03.046
Depositing User:	Users 183 not found.
Date Deposited:	01 Jul 2010 15:30
Last Modified:	06 Feb 2018 13:00
URI:	https://archive.lstmed.ac.uk/id/eprint/868

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