Apical surface topography of invaginating and noninvaginating cells. A scanning-transmission study of amphibian neurulae☆

[摘要] Acomparativestudyonscanningandtransmissionelectronmicroscopyofapicalultrastructureinepitheliaoftheaxolotlneurula(Ambystomamexicanum,Cope)ispresented.Theaimoftheworkistodeterminewhetherapicalsurfacetopographyiscorrelatedtoothermorphologicalfeaturesofthecells,andwhetherthereareanyultrastructuraldifferencesbetweensurfacesofinvaginatingandnoninvaginatingregions.Scanningspecimensarepreparedbycriticalpointdryingandbenzenefreeze-drying.Comparisonsshowthatthescanningspecimensarecomparabletothestandardtransmissionspecimenswithregardtosurfacetopography.Apicalsurfacesaresculpturedbyfoldsandmicrovilli-likeprocesses.Assessmentoftherelativeabundanceofsurfaceprojectionsshowsthattheseoccurinlargestnumbersoninvaginating,bottle-shapedcellsintheneuralplateandinthenotochordrudimentofstage-16larvae.Itisproposedthatthesurfaceprojectionsmaysupportapicalnarrowinginthesecells,byfacilitatingendocytosis,andthattheymaybelateralattachmentorganelles.Itissuggestedthatthemorphogenesisoftheinvaginatingcellsmaybetheresultofcoordinationbetweenmicrofilaments,apicalendocytosis,microtubules,and“adhesiveperipheralsurfaceprojections.”

[学科分类] 生物科学（综合）