An analysis of melanogenesis in differentiating pigment cells of ascidian embryos☆
[摘要] Thelargeotolithandocelluspigmentcellsofthelarvaeoftwoascidianspecies,StyelapartitaandCionaintestinalis,wereusedtoinvestigatethechemicalnatureoftheprecursorandproductofmelaninsynthesisandtheroleofthesemoleculesinmelaningranulogenesis.Phenylthiourea,aninhibitoroftheenzymetyrosinase,preventedmelaninsynthesisintheascidianpigmentcells.Inhibitorreversibilityexperiments,histochemicaltests,andradioautographicexaminationofC14-tyrosineincorporationdemonstratedthatbothtyrosinaseandatyrosine-richprecursormaterialbecameconcentratedandlocalizedinagranule-likevacuoleoftheotolithpigmentcellofembryosrearedinphenylthiourea.Histochemicaltests,C14-labeledaminoacidincorporationexperiments,andinhibitionofproteinsynthesiswithpuromycinandchloramphenicolhaveshownthatthemelanininascidianpigmentcellgranulesisnotsynthesizedasamelanoproteinandthattheprecursormaterialisnotatyrosinepeptide.Freetyrosineappearstobetheprecursorwhichisstoredinthevacuoleofphenylthiourea-inhibitedotolithpigmentcells.Thisinvestigationdefinestwofunctionallydistinctprocessesaspartofmelaningranulogenesis:appearanceandactivityofthetyrosinaseenzyme,andaccumulationofprecursortyrosine.Theseprocessesappeartobecapableofindependentregulation.
[发布日期] [发布机构]
[效力级别] [学科分类] 生物科学（综合）
[关键词] [时效性]
