Diffuse intraembryonic hemopoiesis in normal and chimeric avian development

[摘要] Wehavepreviouslydemonstratedinquailembryosgraftedonchickyolksacstheexistenceofintraembryonicstemcellsresponsiblefordefinitivehemopoiesis.Inordertodeterminetheoriginofthesecells,wenowexaminethediffusehemopoieticprocesseswithintheavianembryo'smesoderm.At4–5daysofincubationinthetwospecies,basophiliccellswerefoundthroughoutthedorsalmesentery.At6–8daysthesecellsbecameverynumerousandbuiltupdensefociatthelevelofbranchingoftheanteriorandposteriorcardinalveins.Thesecellsofteninfiltratedthewalloflymphspacesandchannelsandwerealsopresentinthelumenofbloodvessels.Suchlocationssupporttheinterpretationthatthesebasophiliccellsrepresentearlystagesofhemopoieticdifferentiation.At8–10days,erythropoiesisorgranulopoiesiswasseeninthefoci,whichthenregressedrapidly.Thefocimaximaldevelopmentcoincidedwiththeperiodofcolonizationoftheintraembryonicorganrudiments.In“yolksacchimeras,”thefociwerealwaysconstitutedbyquailcells,indicatingtheirintraembryonicorigin.Theprimordialoriginoftheintramesodermalcellsremainstobedetermined.Alikelysourcemightbetheventralwalloftheaortawhichappearedtoshedcellsintothelumenandintothemesenteryinthe3-dayembryo.

[学科分类] 生物科学（综合）