Studying gastrulation by invagination: The bending of a cell sheet by mechanical cell properties using 3D deformable cell based simulations
Fig 2
Biological images of invagination.
(A–D) Confocal z-stacks of Nematostella vectensis invagination. The images show cross sections of phalloidin stained embryos of Nematostella vectensis at different developmental stages during gastrulation (time of development in hours in left bottom corner). The endodermal plate is directed to the right. (A) The endodermal plate starts to constrict. (B) Invagination continues, the endoderm first aligns laterally and moves aborally. (C) The endodermal and ectodermal layers are fully attached. The embryo has become spherical with a closed off blastoporal opening. (D) After alignment, the endoderm has spread out and reduced its height. Images modified from [31]. (E–I) Favites abdita (Stony coral) invagination. The images show invaginating Favites abdita embryos. (E), (F). Embryos, with oral view of the roundish blastoporal opening, indicated with an asterisk (*). (G). Cross section showing mid-gastrula stage. (H). Cross section showing a fully invaginated embryo with a bowl-like shape and reduced blastoporal opening. (I). The embryo has become more spherical again, and the endodermal layer has reduced its height. Images modified from [9]. (J and K) Initial invaginating plate shapes. Cross sections through invaginating embryos. (J). Flat invaginating endodermal plate shape seen in stony coral (Dipsastraea (Favia) speciosa). The asterisk (*) indicates endodermal plate. (K). Concave invaginating plate shape seen in Aurelia aurita embryo. bl=blastoporal lip. The asterisk (*) indicates the invaginated endodermal plate. Image (J) modified from [9], Image (K) modified from [32]. (L and M). Drosophila ventral furrow invagination. (L). Cross section through a Drosophila embryo and (M). Ventral view of Drosophila embryo. Images (L) modified from [33] Images (M) modified from[34].