Vital dye mapping of the gastrula and neurula of Xenopus laevis: II. Prospective areas and morphogenetic movements of the deep layer☆☆☆

[摘要] Theprospectiveareasinthedeeplayeroftheearlygastrulaweremappedandtheirmorphogeneticmovementsduringgastrulationandneurulationwerefollowedbyvitaldyemarkingofcells.Itwasfoundthatthedeeplayeroftheearlygastrulaconsistsofprospectivemesodermandprospectiveneuralandepidermalectoderm.AtStage10+theprospectivemesodermliesdeeptothesuprablastoporalendodermintheformofathickcollarwhichhasalreadybeguninvolutioninthedorsalsector.Theprospectivenotochordislocatedmiddorsallyandisfollowedlaterally,inturn,byprospectivesomiteandlateralmesoderm.Prospectiveanteriormesoderminvolutesfirst,followedinsuccessionbyprospectivemesodermofmoreposteriorregions.Therelativemovementsoftheneuralandepidermalectodermandtheunderlyingmesodermalmantleduringneurulationweremappedbysimultaneousmarkingofbothlayers.Thesemovementsshowthehighlycoordinatednatureofthethickeningofsomitemesodermandfoldingoftheneuralplate.Strongdorsalconvergenceandventraldivergenceoccurinboththeprospectivemesodermandectoderm.Intheectoderm,dorsalconvergenceofcellsresultsinanteroposteriorextension;however,suchdorsalmovementinthemesodermisabsorbedinthethickeningofthesomiteregion.Theextensionofthedorsalmesodermisbroughtaboutduringneurulationbyadditionofcellsposteriorlyfromtheuninvolutedcircumblastoporalmesoderm.ThesignificanceofthelocationandmovementsofthemesoderminXenopuslaevisisdiscussed.

[学科分类] 生物科学（综合）