Trans-filter propagation of apical ectoderm maintenance factor in the chick embryo wing bud☆☆☆
[摘要] Theexperimentsreportedhereweredesignedtoanalyzetransmissionofthepostulated“apicalectodermmaintenancefactorâ€fromthepostaxialportionofthewing-budstumpintopreaxialtissueofthereorientedwing-budapex.Inembryosofstages20–23,theapicalzoneoftherightwingbudwassevered,reversed(apdv)for5–24hours,andthenrestoredtonormalorientation.Apexesreversedfor12hoursormoredevelopedvaryingdegreesofexcessdigitationpreaxially,rangingfromanextraDigitIItoacompletemirror-twinhand.Extensivemirror-twinduplicationsalsoformedfrompreaxialtissueswithhighfrequency(75%)whentheapicalzonewaspermanentlyreversedwiththinMilliporefilterof0.8μporesizeinterposedbetweenthepostaxialportionofthewing-budstumpandtheapex.Fewerandlesscompleteduplicationsoccurredwithfiltershavingporesizesof0.45μor0.05μ,andnonewerefoundwhenanonporousMylarfilmwasused.Theresultsoftheseexperimentsarecompatiblewiththethesisthatthepostaxialportionofthewing-budstumpisthesourceof“apicalectodermmaintenancefactorâ€whichisrequisitetothemaintenanceoftheapicalridgeofectodermwhichinducesterminallimboutgrowth.Itissuggestedthatactivityofthefactormayinvolvestructuralmaterialwhichisapartofthegroundsubstancebutisrathercloselyassociatedwithcellswhichproduceit.Maintenanceoftheridgemaybearesponsetothisorderedenvironmentortosomeotherfactorwhosefreediffusionisguidedorrestrictedbythisenvironment.
[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]