Stephens T D, Sanders D D, Yap C Y
Department of Biological Sciences, Idaho State University, Pocatello 83209.
J Morphol. 1992 Sep;213(3):305-16. doi: 10.1002/jmor.1052130304.
The present study was undertaken to determine whether a visible Wolffian ridge, distinct from the lateral fold, can be identified in chick embryos. Ectoderm thickness was measured in stage 11-17 chick embryos. There was a general trend, from thin ectoderm in the midline, to an ectodermal thickening over the somites, intermediate mesoderm, and lateral plate. Other embryos were cut from the yolk, pinned out, and photographed. The lateral fold was then eliminated, and the embryo was rephotographed. The photographs reveal a definite opaic zone, distinct from the lateral fold, in stage 11-18 chick embryos. Furthermore, there is a direct correlation between the opacity of this cellular band and the limb-forming potential of grafted wing, flank, and leg regions (see Stephens et al., '89). At stages 11-14, the wing, flank, and leg exhibit a uniform opacity, and a uniform capacity for limb formation when grafted to a host celom. From stage 15 to stage 18, the opacity in the flank diminishes, and its limb-forming capability disappears. This study demonstrates the presence of an opaic zone, which we have called the limb-forming zone (LFZ) along the lateral side of early chick embryos, which is independent of the lateral fold, is not as extensive as the lateral plate, and is not simply associated with ectodermal thickening, but which is directly correlated with limb-forming potential in the lateral plate.
本研究旨在确定在鸡胚中是否能识别出与侧褶不同的明显的中肾嵴。测量了11 - 17期鸡胚的外胚层厚度。存在一种总体趋势，即从中线处较薄的外胚层，到体节、中间中胚层和侧板上方的外胚层增厚。将其他胚胎从卵黄中取出，固定并拍照。然后去除侧褶，再次对胚胎进行拍照。照片显示在11 - 18期鸡胚中存在一个与侧褶不同的明确的不透明区。此外，这条细胞带的不透明度与移植的翅、胁腹和腿部区域形成肢体的潜能之间存在直接相关性（见斯蒂芬斯等人，1989年）。在11 - 14期，翅、胁腹和腿部表现出均匀的不透明度，并且移植到宿主体腔时具有均匀的形成肢体的能力。从15期到18期，胁腹处的不透明度降低，其形成肢体的能力消失。本研究证明沿着早期鸡胚的侧面存在一个不透明区，我们将其称为肢体形成区（LFZ），它独立于侧褶，不如侧板广泛，并且不仅仅与外胚层增厚相关，而是与侧板中形成肢体的潜能直接相关。
