Editorial: Financing for Development: The Progress Money Cannot Buy
Editorial: Financing for Development: The Progress Money Cannot Buy
复制标题
社论：发展融资：金钱买不到的进步
DOI：
10.1057/s41301-017-0096-7
复制
发表时间：
2016
期刊：
影响因子：
4.6
通讯作者：
S. Prato
中科院分区：
文献类型：
--
作者：
S. Prato
假定的原始生殖细胞（pPGCs）的迁移过程中，从他们的深内胚层位置的内胚层嵴非洲爪蟾进行了检查，使用光镜和电子显微镜与Epon部分，和一些形态特征的pPGCs，与他们的迁移，揭示。pPGCs呈多态性，轮廓光滑。pPGCs周围的细胞间隙大而宽，偶见胞质突起，定量分析表明，迁移期的pPGCs有随细胞核定位的前端移动的趋势，将种质拖在后面。这些极化的pPGC经常与大的细胞间隙相关，在它们的前端和尾端。在前端的大细胞间隙中发现极化pPGCs的胞质过程是明显的。超微结构观察，pPGCs细胞核常染色质，核仁明显。光镜下的种质对应于细胞核附近的细胞质区域，在那里聚集了大量嵴发达的线粒体和大多数其他细胞器。在聚集体中观察到的中心粒和中心粒相关微管被认为是负责上述细胞极化的重要结构。结果表明，pPGCs中线粒体的平均大小大于相邻的体细胞内胚层细胞中的线粒体。许多不规则形状的小卵黄血小板特征pPGC。这些超微结构特征表明pPGCs处于活化代谢状态。结果表明，pPGCs的迁移是由于细胞代谢旺盛的主动运动，导致细胞突起的形成和细胞内极化。
Presumptive primordial germ cells (pPGCs) were examined during migration from their deep endodermal position to the endodermal crest in Xenopus laevis , using light and electron microscopy with Epon sections, and several morphological characteristics of pPGCs, associated with their migration, were revealed. pPGCs displayed polymorphism, with smooth contours. The intercellular space around the pPGCs was large and variable in width and cytoplasmic processes from pPGCs were occasionally observed in it. It was shown quantitatively that pPGCs at the migratory stage had a tendency to move with the leading end, towards which the nucleus was localized, dragging the germinal plasm behind. These polarized pPGCs were frequently associated with large intercellular spaces, both at their leading and trailing ends. Cytoplasmic processes of polarizing pPGCs found in the large intercellular space at the leading end were conspicuous. Ultrastructurally, the nuclei of pPGCs were euchromatic, and the nucleolus was prominent. The germinal plasm at the light microscope level corresponded to the cytoplasmic area near the nucleus where a large number of mitochondria with well-developed cristae and most of the other organelles were aggregated. Centrioles and centriole-associated microtubules observed in the aggregate were thought to be important structures responsible for the cell polarization mentioned above. It was demonstrated quantitatively that the size of mitochondria in pPGCs was larger on average than that of mitochondria in neighbouring somatic endodermal cells. Numerous irregularly shaped small yolk platelets characterized pPGCs. These ultrastructural features suggested that pPGCs were in an activated metabolic state. It was concluded that the migration of pPGCs was attributable to active movement with high cell metabolism, causing the formation of cell processes and intracellular polarization.