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dc.contributor.authorScates, Sara Stuarten
dc.date.accessioned2015-11-19T09:00:15Zen
dc.date.available2015-11-19T09:00:15Zen
dc.date.issued2015-11-18en
dc.identifier.othervt_gsexam:4248en
dc.identifier.urihttp://hdl.handle.net/10919/64171en
dc.description.abstractThe incidence of mosquito-borne human diseases is increasing worldwide, with effective chemical control limited due to widespread insecticide resistance in the insect. Recent evidence also suggests that bacterial symbionts of mosquitoes, known to be essential in nutritional homeostasis and pathogen defense, may play a significant role in facilitating mosquitocide resistance. Here, I examined the metabolic detoxification and toxicity of two mosquitocides, propoxur and naled, and the capacity of bacterial symbionts to modify the detoxification of the mosquitocides and, thus, alter their toxic action in the yellow fever mosquito, Aedes aegypti. The insecticide synergists piperonyl butoxide (PBO), triphenyl phosphate (TPP), and S,S,S-tributyl phosphorotrithioate (DEF) were used to examine the metabolic detoxification and toxic action of the two mosquitocides in mosquito larvae. A significant increase in the toxicity of propoxur was observed when applied in combination with PBO; however, there was no corresponding decrease in AChE activity. Naled applied in combination with PBO resulted in a decrease in anticholinesterase activity (higher residual AChE activity) and a subsequent decrease in toxicity of the insecticide. This suggests that esterases play a major role in the metabolic detoxification of both insecticides in mosquito larvae. The acute toxicities of naled and propoxur to Ae. aegypti larvae were also studied following a reduction of bacterial symbionts with the broad-spectrum antibiotics gentamycin, penicillin, and streptomycin. Antibiotic-treated mosquito larvae showed increased susceptibility and a reduction in cytochrome P450 monooxygenase and general esterase activities when treated with naled and propoxur. A reduction of bacteria in mosquito larvae treated with broad-spectrum antibiotics, therefore, appears to affect the metabolic detoxification of standard-use mosquitocides, such as propoxur and naled. The results also suggest that the bacteria themselves may contain metabolic detoxification enzymes that are functionally similar to those in the mosquito larvae. Additional experiments, however, are needed to fully elucidate the contribution of bacterial symbionts in Ae. aegypti larvae in the metabolic detoxification of mosquitocides.en
dc.format.mediumETDen
dc.publisherVirginia Techen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectMosquitoesen
dc.subjectBacteriaen
dc.subjectMosquitocidesen
dc.subjectMetabolic Resistanceen
dc.titleSymbiont-Mediated Modification of Mosquitocide Toxicity in the Dengue Vector, Aedes aegyptien
dc.typeThesisen
dc.contributor.departmentEntomologyen
dc.description.degreeMaster of Science in Life Sciencesen
thesis.degree.nameMaster of Science in Life Sciencesen
thesis.degree.levelmastersen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.disciplineEntomologyen
dc.contributor.committeechairAnderson, Troy D.en
dc.contributor.committeememberBrewster, Carlyle C.en
dc.contributor.committeememberAdelman, Zachary N.en


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