Chromosomal control of foot pad development in Sarcophaga bullata: II. Cuticle formation and tanning☆
[摘要] ThepolytenicpulvillicellsofSarcophagabullatagrowrapidlyduringearlystagesofpupaldevelopment,andapproximately5daysafterpupariumformationtwoofthesecellscovertheentiredorsalsurfaceofthefootpad.Thereplicationoftheirchromosomesterminatesinanextendedphaseofexclusivelydiscontinuousthymidineincorporationandiscompletedduringthe8thdayafterthewhite-pupariumstage.Thesynthesisofcuticlecomponentsofthedorsalfootpadcuticlehasbeenstudiedinisolatedpretarsiculturedinvitro.Asindicatedbytheincorporationofleucine-14Candglucose-14Cthemajorportionofcuticleproteinandchitinofaninnercuticlelayerissynthesizedbetweenday9andday11.Cuticletanningoccursduringa36-hourperiodbetweenday11andday1212.Thespatialandtemporalpatternsofcuticletanningvaryspecificallyforindividualfootpadcells.Duringincubationofpretarsiinvitrotyrosine-14Cincorporationintothedorsalfootpadcuticleproceedsincompletecorrespondencewithcuticletanninginsitu.Mostlikely,thesynthesisofthetanningsubstanceproceedsviatheroutephenylalanine→tyrosine→dopa→dopamine.Correspondingly,phenylalanine,tyrosine,dopa,anddopamineprogressivelystimulatecuticletanninginthisorder.Tyramineseemsexcludedasatanningintermediateinfootpads.Aportionofthetyrosinemetabolitesisapparentlychanneledintotheindole-melaninpathwayandusedinindole-melaninformation.Thesequentialandstage-specificmetabolicchangesandtheirspecificvariationamongdifferenttypesofpulvillicellsisdiscussedinrelationtothesequentialandcelltype-specificchangesinchromosomalpuffingpatterns.
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[效力级别] [学科分类] 生物科学（综合）
[关键词] [时效性]
