AN ULTRASTRUCTURAL ANALYSIS OF CYTOPLASMIC LOCALIZATION IN CHAETOPTERUS PERGAMENTACEUS
AN ULTRASTRUCTURAL ANALYSIS OF CYTOPLASMIC LOCALIZATION IN CHAETOPTERUS PERGAMENTACEUS
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毛甲藻细胞质定位的超微结构分析
DOI：
10.2307/1540883
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发表时间：
1981
期刊：
影响因子：
--
通讯作者：
W. Eckberg
中科院分区：
文献类型：
--
作者：
W. Eckberg
During early development of Chaetopterus pergamentaceus, cytoplasmic com ponents visible by electron microscopy became segregated. The hyaloplasm, or spongy layer, composed of granular bodies surrounded by a matrix of endoplasmic reticulum and microtubules was segregated towards (1) the upper pole of the un fertilized egg, (2) the interior of the cleaving egg, (3) the superficial regions of the 16-cell stage, and (4) the ectoderm of the trochophore larva. The ectoplasm, char acterized by cortical granules, surrounded the unfertilized and cleaving egg en doplasm. It was restricted to the apical end of cells at the 16-cell stage, and to the ectoderm of the trochophore larva. The endoplasm, characterized by yolk and lipid, (1) was found throughout the unfertilized egg except at the upper pole, (2) was restricted to a ring just below the cortex of the cleaving egg, (3) moved to the basal ends of blastomeres by the 16-cell stage, and (4) was limited to the endoderm of the trochophore. Granular bodies were found throughout the embryo. Mitochon dna, found throughout the cytoplasm by first cleavage, were absent from the hy aloplasm of the unfertilized egg. The cytoplasm of the polar lobe was similar to that of the surrounding endoplasm. The localization of morphogenetic determinants was thus accompanied by cytoplasmic organelle localization in Chaetopterus. The results are interpreted in terms of localization mechanisms involving the embryo cortex and ground substances.
