Ishizuya-Oka Atsuko
The Zoological Institute, University of Tokyo, 113, Hongo, Tokyo, Japan.
Wilehm Roux Arch Dev Biol. 1983 May;192(3-4):171-178. doi: 10.1007/BF00848687.
The self-differentiation potency of the endoderm of the chick embryo was investigated mainly by transmission electron microscopy. Endodermal fragments isolated from 4- to 6-day stomach or small intestine were cultured in the absence of mesenchyme and were able to differentiate in vitro into organ-specific epithelia. Endodermal fragments isolated from the stomach region differentiated into a pseudo-stratified epithelium with periodic acid Schiff-positive mucous granules in the apical cytoplasm, while those from the small intestinal region differentiated into a simple columnar epithelium with a striated border which was positive in alkaline phosphatase activity. These features are comparable with those of the mucous secretory epithelium of the normal embryonic stomach and the absorptive epithelium of normal embryonic small intestine, respectively. Next, the self-differentiation potencies were investigated of the upper and lower layers of the blastoderms, at stages 1-5 of Hamburger and Hamilton (H. and H.). Both stomach-type and small-intestine-type epithelia developed only when fragments of the lower layer isolated from the blastoderms older than stage 3 of H. and H. were cultured, suggesting that cells possessing the potency to differentiate into the stomach- and small-intestine-type epithelia exist in the definitive endoderm at the beginning of its formation.
主要通过透射电子显微镜研究了鸡胚内胚层的自我分化能力。从4至6日龄鸡胚的胃或小肠分离出的内胚层片段，在无间充质的情况下进行培养，能够在体外分化为器官特异性上皮。从胃区域分离出的内胚层片段分化为假复层上皮，顶端细胞质中有过碘酸希夫阳性黏液颗粒，而从小肠区域分离出的片段则分化为具有纹状缘的单层柱状上皮，碱性磷酸酶活性呈阳性。这些特征分别与正常胚胎胃的黏液分泌上皮和正常胚胎小肠的吸收上皮的特征相当。接下来，研究了汉密尔顿和汉堡（H.和H.）第1至5阶段胚盘上、下层的自我分化能力。仅当从H.和H.第3阶段以上胚盘分离出的下层片段进行培养时，胃型和小肠型上皮才会发育，这表明在确定内胚层形成之初，就存在具有分化为胃型和小肠型上皮能力的细胞。
