【作者】 张晓辉；

【导师】 卢建平；

【作者基本信息】 浙江大学 ， 动物学， 2002， 硕士

【摘要】 日本沼虾(Macrobrachium nipponense)属于甲壳纲(Crustacea)、十足目(Decapoda)、真虾部(Caridea)、长臂虾科(Palaemonidae)、沼虾属(Macrobrachium)，是我国重要的淡水养殖虾类。输卵管是日本沼虾雌性生殖系统的一个重要组成部分。国内外学者对甲壳动物输卵管的研究报道很少，而关于甲壳动物输卵管超微结构的研究及其在产卵过程中的动态变化过程尚未见报道。本文利用组织学和透射电镜(TEM)技术，研究产卵前后日本沼虾输卵管形态结构变化过程，包括输卵管壁上皮细胞结构的变化过程，上皮细胞之间的连接，及管壁基膜外侧结缔组织细胞。同时观察了日本沼虾胚胎及幼体发育过程中复眼的显微和超微结构。 Ⅰ、输卵管结构主要发现如下： 1、解剖及组织学结构 日本沼虾输卵管一对，发自卵巢两侧，终止于第3步足基节上。输卵管壁由一层上皮细胞、基膜及结缔组织细胞组成。产卵前：输卵管管腔中有大量分泌物；上皮细胞排列紧密，胞核较大，在基膜处细胞呈指状突起。基膜层较薄，外侧有一层结缔组织细胞。产卵后：管腔中分泌物消失，上皮细胞出现死亡，但管壁结构从外形观察仍完整。 2、超微结构 输卵管上皮细胞可分为明细胞和暗细胞两种类型。明细胞较亮，胞质内细胞器种类和数量较多；暗细胞中细胞质密度较大，胞质内细胞器含量较明细胞少；明细胞可由暗细胞发育而成。管壁细胞在近腔处及近基膜处呈手指状突起。 日本沼虾产卵过程对输卵管结构产生显著的影响，产卵前，管腔内有很多分泌物，管壁上皮细胞表面有大量微绒毛，细胞内细胞器如线粒体、内质网、高尔基体等含量丰富，细胞核形态正常。产卵后2小时，管腔内分泌物消失，细胞膜表面稍有破裂，但细胞器大部分保持完整。产卵后1天，管壁细胞解体较产卵后2小时明显，管腔内出现细胞内含物。产卵后3天，管腔内细胞内含物增多，部分管壁细胞的细胞核固缩。产卵后4—8天，管腔中有大量死亡细胞碎片，管壁上皮细胞逐渐开始更新。产卵后第9天，上皮细胞游离面微绒毛开始增多，微绒毛中可见分泌物存在；上皮细胞内细胞器数量逐渐增加，细胞核正常；但细胞结构与产卵前相比仍有较大差别，其微绒毛及分泌物含量，细胞器种类和数量均较产卵前少。产卵后15—18天，管腔中出现许多死亡细胞。同时比较产卵后第8天近卵巢端和近雌性生殖孔端输卵管结构，发现近雌性生殖孔端管壁上皮细胞结构变化较近卵巢端大。这些结果说明日本沼虾输卵管上皮细胞在产卵过程中大部分死亡，产卵后存在更新和补充的过程。 3、产卵后，输卵管管壁上皮细胞多数破裂并死亡，而管壁结构仍保持较完整，这与细胞连接有很大关系。日本沼虾输卵管壁相邻上皮细胞之间第一连接都为桥粒，其余连接为间隔连接且连接数量较多。这种连接方式对于保持输卵管壁结构完整性及维持沼虾体内环境稳定有重要作用。 4、结缔组织细胞与基膜相连，主要有4类。第1类细胞：细胞核中常染色质居多，而其它3类细胞核内异染色质较多。第2类细胞：细胞质内含有许多体积较小的电子致密颗粒。第3类细胞：细胞质内出现较多体积相对较大的电子致密颗粒。第4类细胞：细胞质内粗面内质网呈同心圆分布，具有胞内管腔，为毛细血管管道细胞。第1—3类结缔组织细胞与甲壳动物血细胞比较相似，有可能是管壁上皮细胞更新的重要来源。 5、首次在甲壳动物输卵管壁上皮细胞中发现病毒粒子，这也是日本沼虾体内发现的第一例病毒感染报道。病毒包涵体位于细胞质内，有两种类型。病毒粒子呈圆形，直径约 100urn，外有膜包被。在输卵管管壁上皮细胞中存在病毒粒于，是甲壳动物病毒具有垂直传播途径的一个重要证据。11、胚胎及幼体复眼结构发育的主要发现如下： l、外形结构 日本沼虾受精卵发育到第8天时，胚胎中出现复眼色素。刚开始，只是几个色素点，到9—11天时，点状色素逐渐连成线状并增厚；从第12天开始，色素区域逐渐增大，用戊二醛固定后，可以看到桔红色复眼区；第14天时，复眼区内小眼出现；随着胚胎发育，色素区域继续增大，小眼数量逐渐增多，明显呈辐射状排列，各小眼间界限开始变得清楚；到了第一期搔状幼体，小眼内结构发育己较完善。 2、复眼内小眼细胞来源于外胚层内侧一群共同的细胞增殖区，小眼分化始于远体轴侧并逐渐向近体轴侧进行。 三 3、小眼折光系统包括角膜、角膜细胞及晶锥，晶锥周围有虹膜色素细胞分 布，相邻角膜细胞间有桥粒连接。产卵后14—17天，角膜厚度逐渐增大，角膜 细胞内细胞器数量逐渐增多，晶锥直径也从＊．Znm增加到13urn。产卵后14 天，晶锥内电子颗粒呈块状分布，从产卵后15天开始，晶锥内散状电子颗粒逐渐 增多，产卵后16天，晶锥末端与感杆束相连，附近可见第吕个小网膜细胞。 4、小眼感光系统由8个小网膜细胞组成。小网膜细胞伸出微绒毛组成“十 足目型”（Dec聊da we更多还原

【Abstract】 Macrobrachium nipponense (Crustacean, Decapoda, Caridea, Palaemonidea) is a kind of widely greeding freshwater shrimp in China. Oviduct is one of the main parts of the female reproductive system. In this research, the changes of the structure of the oviduct during spawning and the developments of the compound eyes in the embryonic and larval stages in M nipponense were studied with the methods of histological technology and transmission election microscopy.The structure of oviduct:1. Anatomy and histological structure. A pair of oviducts originates from the anterolateral part of the ovary, and ends at the female genital pores lying in the basipodite of the sixth thorax appendage. The oviduct wall consists of a thin layer of connective tissue, basal lamina and a layer of columnar epithelial cells. Before laying eggs, a lot of secretions appear in oviduct; epithelial cells show tightly each other; near the basal lamina, epithelial cells show finger-like protuberances; the layer of basal lamina is thin and there are another layer of connective tissue cells out of the basal lamina. After laying eggs, secretions disappear and epithelial cells die, but the histological structure of oviduct wall seems integrity.2. Ultrastructure. Two types of epithelial cells are found in oviduct wall, one with clear cytoplasm and the other with dark cytoplasm. The clear cells contain abound organelle compared with the dark cells. Near the oviduct cavity or near the basal lamina, epithelial cells show finger-like protubances.During spawning, the structure of oviduct is obviously affected. Before laying eggs, there are many secretions in oviduct and lots of microvilli at the surface of epithelial cells. The clear cells contain lots of mitochondria, endoplasmic reticulums and Golgi complexes. Two hours after laying eggs, the secretions disappear, and the surfaces of cellular membranes break in a sort, but most of the organelle retainintegrity and cellular inclusions appear in oviduct cavity. Three days later, cellular inclusions increase in oviduct cavity. Four to eight days after laying eggs, there are a lot of death cells in oviduct cavity and the renovation of epithelial cells become evident. Nine days later, microvilli of epithelial cell begin to increase, and secretions among mocrovilli also can be seen, and hi the cytoplasm the amount of organelle increases gradually. But comparied with that before laying eggs, the amount of microvilli, secretions, types and amount of organelle are few too. From fifteen days to eighteen days, a great deal of death cells can also be seen in oviduct cavity. In addition, eight days after laying eggs, it is found that cellular structures of oviduct near the female genital pores vary greater than those near the ovary during or after spawning eggs.3. After laying eggs, most of epithelial cells break and die, however, histologically, the structure of oviduct wall still remains normal. The reason should be relative to cellular junctions. Desmosomes appear between epithelial cells as the first junctions, and septate junctions widely exist between or among epithelial cells. It is believed that these junctions are important to remain the structure of oviduct and keep stable environment in vivo in Macrobrachium nipponense.4. Four different types of connective tissue cells are found out of the basal lamina, hi the first type of connective tissue cells, most of the nuclei are occupied by normal chromatins, but in other three types of connective tissue cells, abnormal chromatins are rich in nuclei. In addition, there are many small eletron dense granules in the second type of connective tissue cells and big eletron dense granules in the third type of connective tissue cells. The fourth types are stract cells, where endoplasmic reticulums showed concentric circle. It is found that the first, second and third types of connective tissue cells, which are analogous to crustacean haemocytes, are probably the originations of the renovation of epithelial cells.5. Virions in epithelia更多还原