title: Silencing an Anopheles gambiae catalase and sulfhydryl oxidase increases mosquito mortality after a blood meal.
abstract: Catalase is a potent antioxidant, likely involved in post-blood meal homeostasis in mosquitoes. This enzyme breaks down H2O2, preventing the formation of the hydroxyl radical (HO*). Quiescins are newly classified sulfhydryl oxidases that bear a thioredoxin motif at the N-terminal and an ERV1-like portion at the C-terminal. These proteins have a major role in generating disulfides in intra- or extracellular environments, and thus participate in redox reactions. In the search for molecules to serve as targets for novel anti-mosquito strategies, we have silenced a catalase and a putative quiescin/sulfhydryl oxidase (QSOX), from the African malaria vector Anopheles gambiae, through RNA interference (RNAi) experiments. We observed that the survival of catalase- and QSOX-silenced insects was reduced over controls following blood digestion, most likely due to the compromised ability of mosquitoes to scavenge and/or prevent damage caused by blood meal-derived oxidative stress. The higher mortality effect was more accentuated in catalase-silenced mosquitoes, where catalase activity was reduced to low levels. Lipid peroxidation was higher in QSOX-silenced mosquitoes suggesting the involvement of this protein in redox homeostasis following a blood meal. This study points to the potential of molecules involved in antioxidant response and redox metabolism to serve as targets of novel anti-mosquito strategies and offers a screening methodology for finding targetable mosquito molecules.
authors.affiliation: Department of Epidemiology and Public Health, University of Miami, Miami, Florida, USA. teca@cpqam.fiocruz.br
authors.forename: T
authors.initials: T
authors.lastname: Magalhaes
authors.forename: D E
authors.initials: DE
authors.lastname: Brackney
authors.forename: J C
authors.initials: JC
authors.lastname: Beier
authors.forename: B D
authors.initials: BD
authors.lastname: Foy
mesh_terms: D000818:Animals; D000852:Anopheles / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D002374:Catalase / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D005260:Female; D053208:Kaplan-Meier Estimate; D051379:Mice; D010088:Oxidoreductases / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D012330:RNA, Double-Stranded / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism; D014158:Transcription, Genetic; D050862:Oxidoreductases Acting on Sulfur Group Donors
chemical_list: D002374:Catalase; D010088:Oxidoreductases; D012330:RNA, Double-Stranded; D017392:Thiobarbituric Acid Reactive Substances; D050862:Oxidoreductases Acting on Sulfur Group Donors