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dc.contributor.authorKoganemaru, Reinaen_US
dc.date.accessioned2016-11-23T07:01:19Z
dc.date.available2016-11-23T07:01:19Z
dc.date.issued2015-06-01en_US
dc.identifier.othervt_gsexam:4981en_US
dc.identifier.urihttp://hdl.handle.net/10919/73497
dc.description.abstractThe Common bed bug, Cimex lectularius L., suddenly reappeared in developed countries in the past 15 years. The factor contributing to the sudden resurgence of the bed bugs is insecticide resistance. In this study, we investigated the mechanisms of reduced cuticular penetration type insecticide resistance in bed bugs. First, we determined and compared the lethal dosage (LD50) of a pyrethroid insecticide using topical and injection application. The resistant strain not only had significantly greater resistance ratios, but also demonstrated significantly greater penetration resistance ratios. This provided the evidence of the reduced cuticular penetration in bed bugs. Second, we determined the levels of gene transcription (CPR-type cuticle protein genes) using real-time quantitative polymerase chain reaction (qRT-PCR). We identified 62 putative bed bug cuticle protein-encoding contigs based on the presence of the Chitin-binding 4 (CB4) domain. Based on the qRT-PCR analysis of the mRNAs, we found many of the genes were up-regulated in the resistant strain suggesting thickening of the cuticle or increasing the cuticular proteins might be involved in the reduced cuticular penetration. Third, we identified and described the cuticular proteins using the matrix-assisted laser desorption/ionization (MALDI) time-of-flight/time-of-flight (TOF/TOF) high-resolution tandem mass spectrometry (MALDI-TOF/TOF). The total of 265 peptides were identified, among which 206 belonged to one of 50 confidently identified proteins. We identified the CPRL, CPF, CPFL, TWDL, and CPAP1 family proteins. The profile of the cuticular proteins between the resistant and the susceptible strains bed bugs were almost identical. Fourth, we determined and compared the cuticular thickness using Scanning Electron Microscopy (SEM). We found statistical differences of the cuticular thickness among different strains (populations), however, correlation between the levels of insecticide resistance and cuticular thickness were not found. Finally, we identified and described bed bug cuticular hydrocarbon profiles using Gas-Chromatography and Mass-Spectrometry (GC-MS). The total of 87 compounds in addition to n-alkanes were extracted and identified. There were no correlation found with the concentration and the levels of insecticide resistance. However, several additional compounds exhibited the correlation between the concentration of the compounds and the levels of insecticide resistance. Overall, we found three lines of evidence to support reduced cuticular penetration as a mechanism of insecticide resistance in some bed bug populations. This study provides additional evidence of the reduced cuticular penetration type resistance in bed bugs.en_US
dc.format.mediumETDen_US
dc.publisherVirginia Techen_US
dc.rightsThis Item is protected by copyright and/or related rights. Some uses of this Item may be deemed fair and permitted by law even without permission from the rights holder(s), or the rights holder(s) may have licensed the work for use under certain conditions. For other uses you need to obtain permission from the rights holder(s).en_US
dc.subjectCimex lectularius L.en_US
dc.subjectreduced cuticular penetrationen_US
dc.subjectLD50en_US
dc.subjectinsect cuticular genesen_US
dc.subjectcuticular proteinsen_US
dc.subjectcuticular hydrocarbonsen_US
dc.subjectScanning Electron Microscopy (SEM)en_US
dc.titleReduced cuticular penetration as a contributor to insecticide resistance in the common bed bug, Cimex lectularius L.en_US
dc.typeDissertationen_US
dc.contributor.departmentEntomologyen_US
dc.description.degreePh. D.en_US
thesis.degree.namePh. D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen_US
thesis.degree.disciplineEntomologyen_US
dc.contributor.committeechairMiller, Dini M.en_US
dc.contributor.committeememberAnderson, Troy D.en_US
dc.contributor.committeememberAdelman, Zachary N.en_US
dc.contributor.committeememberFisher, Marc Lewisen_US
dc.contributor.committeememberTu, Zhijianen_US


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