FINE STRUCTURE AND ITS FUNCTIONAL PROPERTIES OF ENDOSTYLE OF ASCIDIANS, CIONA-INTESTINALIS - PART OF PHYLOGENETIC STUDIES OF THYROID GLAND
FINE STRUCTURE AND ITS FUNCTIONAL PROPERTIES OF ENDOSTYLE OF ASCIDIANS, CIONA-INTESTINALIS - PART OF PHYLOGENETIC STUDIES OF THYROID GLAND
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DOI：
10.1007/bf00560154
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发表时间：
1971-01-01
期刊：
影响因子：
--
通讯作者：
NANBA, H
中科院分区：
文献类型：
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作者：
FUJITA, H;NANBA, H
为了解甲状腺肿的发生，用电镜和电镜放射自显影技术研究了海鞘（Ciona caulifa）内柱的精细结构和碘代谢。内柱有8种区带，1、3、5区细胞，特别是1区细胞具有大量的长纤毛。这些细胞没有蛋白质分泌的迹象，但有许多小泡和胞质丝，可能在捕获和运输食物、吸收液体和支持花柱内壁结构方面起作用。和6细胞大，特征是发达的粗面内质网和大量的电子-致密的分泌颗粒，被认为是在粗面内质网中合成并运输到高尔基体成熟。第7区和第8区细胞与高等脊椎动物甲状腺细胞同源，粗面内质网不发达，高尔基体小，多泡体少，溶酶体少，小泡多。此外，第8区细胞在其顶面上具有纤毛。这些细胞类型的细胞质特征，特别是区8细胞，是相当相似的2C型和3型细胞的幼虫七鳃鳗的endostyle，虽然粗面内质网不是那么发达。用电镜放射自显影法观察到，在含125 I的海水浸泡后1、4、6、16和24 h，第7区和第8区细胞，特别是第8区细胞的细胞膜顶端有大量的银颗粒。这一事实表明碘化发生在这些细胞的顶端细胞膜区域。在组织的固定和脱水过程中，柄内腔中的物质被冲走。因此，不能排除甲状腺球蛋白样物质碘化发生在茎内膜腔内的可能性。在4、6、16和24小时后，多泡体和溶酶体中也发现颗粒，尤其是16和24小时。看来有机碘可能被这些细胞的细胞质重吸收。
For the purpose used in understanding thyroid phylogenesis, the fine structure and the iodine metabolism of the endostyle of Ascidians,Ciona intestinalis, was studied by electron microscopy and electron microscopic autoradiography. There are 8 kinds of zones in the endostyle.Zone 1, 3, and 5 cells, especially zone 1 cells, are characterized by numerous long cilia. These cells which show no indications of protein-secretion but numerous small vesicles and cytoplasmic filaments might play a role in catching and transporting food, absorption of liquid and supporting the endostylar construction.Zone 2, 4, and 6 cells are large and characterized by well developed rough endoplasmic reticulum and numerous electron-dense secretory granules which are considered to be synthesized in the rough endoplasmic reticulum and transported to the Golgi apparatus to mature. They, which are somewhat similar to the pancreatic exocrine cells in fine structure, are believed to secrete the proteinous or mucoproteinous substances which might be related to the digestion of food.Zone 7 and 8 cells which might be homologous to the thyroid cell of the higher vertebrate contains poorly developed rough endoplasmic reticulum, small Golgi apparatus, a few multivesicular bodies, a few lysosomes, and numerous small vesicles. In addition zone 8 cells bear cilia on their apical surface. The cytoplasmic characteristics of these cell types, especially of zone 8 cells, are fairly similar to those of type 2C and type 3 cells of the endostyle of a larval lamprey, though the rough endoplasmic reticulum is not so well developed. By electron microscopic autoradiography numerous silver grains were observed on the apical cell membrane region of zone 7 and 8 cells, especially of zone 8 cells, 1, 4, 6, 16 and 24 hours after immersion in sea water containing125I. This fact suggests that the iodination takes place in the apical cell membrane region of these cells. The materials in the endostylar lumen is washed away during the fixation and dehydrating processes of the tissue. Therefore, the possibility of iodination of thyroglobulin-like substances taking place within the endostylar lumen cannot be ruled out. Grains were also found in the multivesicular bodies and lysosomes after 4, 6, 16 and 24 hours, especially 16 and 24 hours. It seems that the organic iodine might be reabsorbed into the cytoplasm of these cells.