Veini Marianne, Hara K
Hubrecht Laboratory, Uppsalalaan 1, De Uithof, Utrecht, Netherlands.
Zoological Laboratory, University of Athens Panepistimiopolis (Kouponia), 621, Athens, Greece.
Wilehm Roux Arch Dev Biol. 1975 Jun;177(2):89-100. doi: 10.1007/BF00848524.
Hensen's node was isolated from chick blastoderms of medium-streak to headfold stages from which the endodermal layer had previously been removed. The isolates were culturedin vivo by means of the intra-coelomic grafting technique. Node pieces with the endodermal layer intact served as controls.Endodermal differentiation tendencies gradually decreased from the medium-streak to the pre-head-process stage and completely disappeared at the head-process stage, whereas the controls gave rise to endodermal structures throughout all stages. "Cranial" structures such as oesophagus and trachea, often together with thyroid, parathyroid and/or thymus, were only found in grafts of younger stages, while gizzard, intestine and/or pancreas were observed in many gut-containing grafts throughout all stages.There was a constant high incidence of notochord, muscle, and cartilage formation. The incidence of mesonephric structures, sometimes accompanied by adrenal gland, rose steadily throughout all stages both in experimentals and controls.Neural differentiation tendencies (rhombencephalon and/or spinal cord) were always present in the nodes isolated (with or without endoderm) from the definitive primitive-streak stage onwards, but in nodes from earlier stages the incidence of neural differentiation was significantly lower.The results are discussed in relation to the possible location and determination of the prospective endoderm and mesoderm.
从处于中胚层期至头褶期的鸡胚胚盘分离出亨氏结，这些胚盘的内胚层先前已被去除。通过体腔移植技术在体内培养分离物。内胚层完整的结块用作对照。从原条中期到原头突前期，内胚层分化趋势逐渐降低，在原头突期完全消失，而对照在所有阶段都产生内胚层结构。“头部”结构，如食管和气管，通常与甲状腺、甲状旁腺和/或胸腺一起，仅在较早期阶段的移植中发现，而在所有阶段的许多含肠道移植中都观察到砂囊、肠道和/或胰腺。脊索、肌肉和软骨形成的发生率一直很高。中肾结构的发生率，有时伴有肾上腺，在实验和对照的所有阶段都稳步上升。从确定的原条期开始，在分离出的（有或没有内胚层的）结中始终存在神经分化趋势（后脑和/或脊髓），但在早期阶段的结中，神经分化的发生率明显较低。讨论了这些结果与预期内胚层和中胚层可能的位置及决定作用的关系。
