| 摘要: |
| 于1993-1994年在厦门海区采集长毛对虾雄性成虾，取其精巢、输精管和精荚，采用JEM-100CXll透射电镜观察长毛对虾精子形成过程的超微结构，并根据项体形成过程中超微结构的变化进行分期。结果表明：长毛对虾精于形成过程可分为早期精子细胞、中期精子细胞、晚期精子细胞及成熟精子四个时期。在早期精子细胞阶段，细胞质中含有丰富的粗面内质网，其周围分布着许多大小不一的囊泡，囊泡融合成前顶体囊，囊内合成前项体颗粒物质。中期棘突原基形成。后期棘突原基进一步浓缩，并向前突出。成熟精子期整个前顶体囊分化为棘突和内、外顶体层．在精子形成过程中，细胞质先囊泡化后移至细胞的一极，同时不断减少，最后只剩下一些残余的扁平小泡样膜相结构，成一薄层包绕于细胞核外。细胞核也经历了三次形态变化，染色质从去浓缩变成弥散状态到重又浓缩为凝絮状；随着发生过程中精子染色质的变化，核膜也崩解，至成熟精子已无完整核膜存在。这些结果说明，长毛对虾与大多数十足目动物类似，精子的顶体物质系由粗面内质网合成。细胞核内染色质的演化，推测与其核骨架与核蛋白的演化是相对应的，是DNA与蛋白质相互作用的结果。 |
| 关键词: 长毛对虾 精子形成 超微结构 |
| DOI： |
| 分类号: |
| 基金项目:福建省自然科学基金资助项目，C95030号;中国科学院昆明动物研究所细胞与分子进化开放实验室资助项目 |
附件 |
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| ULTRASTRUCTURE OF SPERMIOGENESIS IN THE SHRIMP PENAEUS PENICILLATES |
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WANG Yi-lei,ZHANG Zi-ping,LI Shao-jing
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1.Fisheries College, Jimei University, Xiamen, 361021;2.Departmnt of Biology and Chemisny, City University of Hong Kong, Kowloon, Hong Kong;3.Oceanography Department, Xiamen University, Xiamen, 361005
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| Abstract: |
| From 1993 - 1994, mature male shrimp Penaeus penicillate were collected from the coastal areas of Xiamen. Testes, vasa deferentia and sperrnatophores were cut into small fragments and fixed for 2h at 4°C in 2.5% glutaraldehyde, postfixed for 2h at 4°C in 1% osmium tetroxide, and embedded in 618# resin. Thin sections were cut with glass knives, contrasted with uranyl acetate and lead citrate, and examined on JEM-l00CXII transmission electron microscope.
The study shows that the spermiogenesis of Penaeus penicillates can be divided into four successive stages, namely early spermatid, mid spermatids, late spermatids and mature spermatozoa.
Early spermatid possesses numerous rough endoplasmic reticulum and small vesicles; some of vesicles coalesce with the large proacrosomal vesicle. The nucleus and the voluminous proacrosomal vesicle occupy both cell poles. Within proacrosomal vesicle, the proacrosomal granulated material develops. The nucleus shows extensive areas of condensed chromatin and is entirely separated from the cytoplasm by the nuclear envelope.
In mid spermatids, the nucleus has become uncondensed and the perinuclear cytoplasm is considerably reduced. The chromatin is ?nely granular in appearance. The nuclear envelope has reptured. Proacrosomal granulated material has formed a primordial spike.
In late spermatids, the primordial spike tends to elongate progressively. After reduction in volume, the perinuclear cytoplasm forms a thin band around the nuclear region. The chromatin also undergoes morphologic change to form a flocculent pattern.
In the stage of mature spermatozoa, proacrosomal vesicle further develops into spike, inner acrosomal layer and outer acrosomal layer. The nuclear and cytoplasm have not changed significantly in this stage.
To sum up, during the spermiogenesis in Penaeus penicillates, the chromatin undergoes three morphologic changes. The initially continuous nuclear envelope breaks up, allowing for free nucleocytoplasmic exchange. Proacrosomal vesicles are thought to derive from rough endoplasmic reticulum. |
| Key words: Penaeus penicillares, Spenniogenesis, Ultrastructure |
