Beloussov L V, Lakirev A V, Naumidi I I, Novoselov V V
Department of Embryology, Moscow State University, USSR.
Int J Dev Biol. 1990 Dec;34(4):409-19.
In Xenopus laevis embryos at the early gastrula stage, circumferential tensions of embryonic ectoderm were relaxed by making sagittal or transversal slits in the ventral parts of embryos and inserting into surgical cuts the sectors of homologous tissue from same-stage embryos. Changes in tensile patterns were controlled by measuring cell surface angles. Immediate decreases in surface cell wall tension as related to transversal wall tension were registered. Within minutes of the operation, the lobopodial activity of the inner ectodermal surface increased. The subsequent gastrulation movements were disturbed, germ layers partially mixed and archenteron reduced. The areas of extensive cell columnarization in the ectoderm of operated embryos were less regularly arranged and were extended much more ventrally than in intact embryos. Ventro-dorsal migration and latero-medial intercalation of mesodermal cells also were suppressed. As the operated embryos developed, we observed increases in the total amount of neural tissue, associated sometimes with duplication and even triplication of neural tubes, duplication of otic vesicles, partial fusion of axial rudiments, suppression of mesodermal segmentation and branching or bending of notochord. In the gravest cases the antero-posterior embryo polarity was disturbed. In some cases we observed the formation of axial rudiments in ventral implants. The role of tensions in determining the patterns of morphogenetic cell movements and in establishing the morphological order of normal development is discussed.
在非洲爪蟾早期原肠胚阶段的胚胎中，通过在胚胎腹部做矢状或横向切口，并将来自同阶段胚胎的同源组织切片插入手术切口，来放松胚胎外胚层的圆周张力。通过测量细胞表面角度来控制拉伸模式的变化。记录到与横向壁张力相关的表面细胞壁张力立即下降。手术几分钟内，内胚层表面的叶足活动增加。随后的原肠胚形成运动受到干扰，胚层部分混合，原肠缩小。手术胚胎外胚层中广泛细胞柱状化的区域排列不如完整胚胎规则，且比完整胚胎更向腹侧延伸。中胚层细胞的腹背迁移和左右内侧插入也受到抑制。随着手术胚胎的发育，我们观察到神经组织总量增加，有时伴有神经管的重复甚至三倍化、耳泡的重复、轴突原基的部分融合、中胚层节段化的抑制以及脊索的分支或弯曲。在最严重的情况下，胚胎的前后极性受到干扰。在某些情况下，我们观察到腹侧植入物中轴突原基的形成。本文讨论了张力在决定形态发生细胞运动模式和建立正常发育的形态学秩序中的作用。
