Functional and immunohistochemical characterization of CCEae3a, a carboxylesterase associated with temephos resistance in the major arbovirus vectors Aedes aegypti and Ae. albopictus

Grigoraki, Linda, Balabanidou, Vassileia, Meristoudis, Christos, Miridakis, Antonis, Ranson, Hilary ORCID: https://orcid.org/0000-0003-2332-8247, Swevers, Luc and Vontas, John (2016) 'Functional and immunohistochemical characterization of CCEae3a, a carboxylesterase associated with temephos resistance in the major arbovirus vectors Aedes aegypti and Ae. albopictus'. Insect Biochemistry and Molecular Biology, Vol 74, Issue July 2016, pp. 61-67.

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Abstract

Temephos is a major organophosphate (OP) larvicide that has been used extensively for the control of Aedes albopictus and Aedes aegypti, the major vectors for viral diseases, such as dengue fever, zika and chikungunya. Resistance to temephos has been recently detected and associated with the upregulation of carboxylesterases (CCEs) through gene amplification, in both species. Here, we expressed the CCEae3a genes which showed the most striking up-regulation in resistant Aedes strains, using the baculovirus system. All CCEae3a variants encoded functional enzymes, with high activity and preference for p-nitrophenyl butyrate, a substrate that was shown capable to differentiate temephos resistant from susceptible Aedes larvae. Enzyme kinetic studies showed that CCEae3as from both Ae. aegypti and Ae. albopictus (CCEae3a_aeg and CCEae3a_alb, respectively) strongly interact with temephos oxon and slowly released the OP molecule, indicating a sequestration resistance mechanism. No difference was detected between resistant and susceptible CCEae3a_aeg variants (CCEae3a_aegR and CCEae3a_aegS, respectively), indicating that previously reported polymorphism is unlikely to play a role in temephos resistance. HPLC/MS showed that CCEae3as were able to metabolize temephos oxon to the temephos monoester [(4-hydroxyphenyl) sulfanyl] phenyl O,O-dimethylphosphorothioate. Western blot and immunolocalization studies, based on a specific antibody raised against the CCEae3a_alb showed that the enzyme is expressed at higher levels in resistant insects, primarily in malpighian tubules (MT) and nerve tissues.

Item Type:	Article
Subjects:	QX Parasitology > Insects. Other Parasites > QX 525 Aedes QX Parasitology > Insects. Other Parasites > QX 650 Insect vectors WA Public Health > Preventive Medicine > WA 240 Disinfection. Disinfestation. Pesticides (including diseases caused by) WC Communicable Diseases > Virus Diseases > Infectious Mononucleosis. Arbovirus Infections > WC 524 Arbovirus infections WC Communicable Diseases > Virus Diseases > Infectious Mononucleosis. Arbovirus Infections > WC 528 Dengue
Faculty: Department:	Biological Sciences > Vector Biology Department
Digital Object Identifer (DOI):	https://doi.org/10.1016/j.ibmb.2016.05.007
Related URLs:	https://doi.org/10.1016/j.ibmb.2017.05.0...
Depositing User:	Jessica Jones
Date Deposited:	19 May 2016 10:42
Last Modified:	30 Aug 2019 17:06
URI:	https://archive.lstmed.ac.uk/id/eprint/5891

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