berghei gametocytes A) and exflagellating microgametes B) were differentiated by morphology. Polyclonal antisera specific for target protein ...ArticleAuthorsMetricsCommentsMediaCoverageReaderComments(0)FiguresFiguresAbstractThePlasmodiumookinetedevelopsoverseveralhoursinthebloodmealofitsmosquitovectorwhereitisexposedtoexogenousstresses,includingcytotoxicreactiveoxygenspecies(ROS).Howtheparasiteadaptstothesechallengingconditionsisnotwellunderstood.Wehavesystematicallyinvestigatedtheexpressionofthreecytosolicantioxidantproteins,thioredoxin-1(Trx-1),peroxiredoxin-1(TPx-1),and1-Cysperoxiredoxin(1-CysPrx),indevelopingookinetesoftherodentparasitePlasmodiumbergheiundervariousgrowthconditions.Transcriptionalprofilingshowedthattpx-1and1-cysprxbutnottrx-1aremorestronglyupregulatedinookinetesdevelopinginthemosquitobloodmealwhencomparedtoookinetesgrowingundercultureconditions.Confocalimmunofluorescenceimagingrevealedcomparableexpressionpatternsonthecorrespondingproteins.1-CysPrxinparticularexhibitedstrongexpressioninmosquito-derivedookinetesbutwasnotdetectableinculturedookinetes.Furthermore,ookinetesgrowingincultureupregulatedtpx-1and1-cysprxwhenchallengedwithexogenousROSinadose-dependentfashion.ThissuggeststhatenvironmentalfactorsinthemosquitobloodmealinduceupregulationofcytosolicantioxidantproteinsinPlasmodiumookinetes.WefoundthatinaparasitelinelackingTPx-1(TPx-1KO),expressionof1-CysPrxoccurredsignificantlyearlierinmosquito-derivedTPx-1KOookineteswhencomparedtowildtype(WT)ookinetes.TheproteinwasalsoreadilydetectableinculturedTPx-1KOookinetes,indicatingthat1-CysPrxatleastinpartcompensatesforthelossofTPx-1invivo.WehypothesizethatthisdynamicexpressionofthecytosolicperoxiredoxinsreflectsthecapacityofthedevelopingPlasmodiumookinetetorapidlyadapttothechangingconditionsinthemosquitobloodmeal.Thiswouldsignificantlyincreaseitschancesofsurvival,maturationandsubsequentescape.OurresultsalsoemphasizethatenvironmentalconditionsmustbetakenintoaccountwheninvestigatingPlasmodium-mosquitointe