东方扁虾卵子发生的超微结构

根据卵细胞的形态、内部结构特征及卵母细胞与滤泡细胞之间的关系,东方扁虾的卵子发生可划分为卵原细胞、卵黄发生前卵母细胞、卵黄发生卵母细胞和成熟卵母细胞等四个时期。卵原细胞胞质稀少,胞器以滑面内质网为主。卵黄发生前卵母细胞核明显膨大,特称为生发泡;在靠近核外膜的胞质中可观察到核仁外排物。卵黄发生卵母细胞逐渐为滤泡细胞所包围;卵黄合成旺盛,胞质中因而形成并积累了越来越多的卵黄粒。东方扁虾卵母细胞的卵黄发生是二源的。游离型核糖体率先参与内源性卵黄合成形成无膜卵黄粒。粗面内质网是内源性卵黄形成的主要胞器。滑面内质网、线粒体和溶酶体以多种方式活跃地参与卵黄粒形成。卵周隙内的外源性物质有两个来源:滤泡细胞的合成产物和血淋巴携带、转运的卵黄蛋白前体物。这些外源性物质主要通过质膜的微吞饮作用和微绒毛的吸收作用这两种方式进入卵母细胞,进而形成外源性卵黄。内源性和外源性的卵黄物质共同参与成熟卵母细胞中富含髓样小体的卵黄粒的形成。卵壳的形成和微绒毛的回缩被认为是东方扁虾卵母细胞成熟的形态学标志。       

体外培养日本血吸虫成虫生殖器官超微结构的观察

将日本血吸虫成虫于851培养基中培养23天后,对其生殖器官进行透射电镜观察。观察结果显示,雌虫卵巢内卵母细胞出现不同程度的变性、坏死;成熟卵黄细胞的卵黄小滴融合,脂质小滴数量增多、体积增大;培养后期卵壳形成发生障碍,最终导致无活性、无卵壳的畸形卵形成。超微结构观察首次显示,体外初产期虫卵卵壳中有条带状低电子密度区和高电子密度区相间排列。     

南美白对虾卵子发生的组织学

采用组织学方法研究了南美白对虾的卵子发生过程,根据卵细胞大小、核仁形态、卵黄粒的有无、皮质棒的出现以及卵母细胞与滤泡细胞的关系,将南美白对虾的卵子发生划分为卵原细胞、卵黄发生前的卵母细胞和卵黄发生的卵母细胞三个时期,并描述了各期卵细胞的形态特征。     

前培养对猪卵母细胞生发泡染色质构型和体外成熟的影响

在体外成熟培养时使卵母细胞过早接触高浓度激素可能影响体外成熟卵母细胞的质量。本实验研究了推迟卵母细胞与激素接触时间对卵母细胞GV染色质构型、卵母细胞核成熟质量及极体形态的影响。结果表明：猪体外成熟卵母细胞的极体形态不同,分为完整、退化、碎裂和无极体四种。在不含激素培养液中前培养12h,A类卵母细胞的GV-1比例(48．2％)明显高于在含激素培养液中前培养12h卵母细胞(27．1％);而前者的GV-3比例(19．6％)却明显低于后者(50．8％);前者成熟卵母细胞的极体完整率(59．6％)也明显高于后者(27．5％)。这说明推迟卵母细胞与激素接触时间可能提高体外成熟卵母细胞的质量和发育同步水平。     

黄胫小车蝗卵子发生及卵母细胞凋亡的显微观察

对黄胫小车蝗(Oedaleus infernalis)卵子发生过程和卵母细胞凋亡进行显微观察。结果表明,黄胫小车蝗卵子发生可明显分为3个时期10个阶段,即卵黄发生前期、卵黄发生期和卵壳形成期。第1阶段,卵母细胞位于卵原区,经历减数第一次分裂;第2阶段,卵母细胞核内染色体解体成网状,滤泡细胞稀疏地排列在卵母细胞周围;第3阶段,滤泡细胞扁平状,在卵母细胞周围排成一层;第4阶段,滤泡细胞呈立方形排在卵母细胞周围;第5阶段,滤泡细胞呈长柱形排在卵母细胞周围,滤泡细胞之间、滤泡细胞与卵母细胞之间出现空隙;第6阶段,卵母细胞边缘开始出现卵黄颗粒;第7阶段,卵母细胞中沉积大量卵黄,胚泡破裂;第8阶段,滤泡细胞分泌卵黄膜包围卵黄物质;第9阶段,滤泡细胞分泌卵壳;第10阶段,卵壳分泌结束,卵子发育成熟。卵母细胞发育过程中的凋亡发生在卵黄发生前期,主要表现为滤泡细胞向卵母细胞内折叠,胞质呈团块状等特征。     

锯缘青蟹卵黄发生期卵母细胞和卵泡细胞之间的结构变化

通过电镜研究了锯缘青蟹二次卵巢发育过程中卵黄发生期（分为初期和后期）卵母细胞表面的结构和胞质的变化。卵黄发生初期分为：内源性卵黄发生阶段和有卵泡细胞直接参与的外源性卵黄合成阶段,前者特征为：在卵母细胞中充满了内质网泡,在泡内有不同程度的卵黄物质合成,此时在卵母细胞的表面区域,可见很多卵泡细胞向卵母细胞表面迁移,并包围卵母细胞。后者其特征是在卵母细胞的表面,有大量的胞饮小泡出现在卵膜的内面,随着两细胞表面膜的逐步融合和胞饮作用加强最后形成链锁状结构,胞质中靠近卵质周围有卵黄体的积极合成和大更换 脂肪滴积累,在此阶段的后期,卵泡细胞质已基本吸收完毕,卵泡细胞膜和卵母细胞膜融合,某些界面已无膜结构。卵黄发生后期在亲蟹孵出幼体后的第11d至第27d基本结束,此期也主要以外源性卵黄发生为主,在卵母细胞的周围,卵泡细胞迅速扩大,其间分布着大量的大小不同的囊泡和线粒体,在接近卵母细胞表面,还常可见大量的脂肪滴存在。卵泡细胞与卵母细胞间其膜结构完全消失,从而可使滤泡大片细胞质直接融入卵母细胞中,以后随着卵黄发生的进一步发展,卵母细胞与卵泡细胞的交界面逐步形成一个网状的膜结构屏障,同时在卵巢中可见正在降解的卵母细胞,在卵黄发生近结束以后,在卵母细胞的表面,逐步形成两层卵膜,这时的卵母细胞质中几乎充满了卵黄体和脂肪滴。     

七星瓢虫雌成虫咽侧体的活性

以短期体外放射化学测定法测定了七星瓢虫雌成虫的咽侧体(CA)活性。结果表明,七星瓢虫的CA在TC 199培养液中培养时活性最高。在最适培养条件下CA合成保幼激素(JH)的速度在1—4小时呈直线增加。 七星瓢虫雌虫生殖期CA的活性变化与卵黄发生有相关性。羽化初期CA活性很低,羽化后4—8天CA活性增加,卵母细胞内卵黄沉积开始增多;羽化后8—12天CA活性高峰出现,此时卵母细胞内有大量卵黄沉积;羽化后12—15天CA活性下降,卵完全成熟并陆续出现产卵个体。 食料对七星瓢虫成虫的卵黄发生的影响:取食人工饲料雌虫的CA活性增长缓慢,直至羽化后15天CA活性仍很低,因而抑制了卵黄原蛋白的合成,使卵巢发育缓慢。此种雌虫中CA活性高峰的出现比取食蚜虫的延迟约2倍,前者的产卵前期也较后者延长约2倍。     

Gas6在猪卵母细胞及早期胚胎中表达模式与功能的初步研究

该研究通过免疫组化和QRT-PCR等方法系统分析了Gas6（growth arrest-special gene 6）基因在猪卵泡发生及早期胚胎发育过程中的表达规律,并提出了一种改良猪卵母细胞体外成熟系统的方法。研究结果显示,Gas6基因表达于猪卵巢中的卵母细胞细胞核及其周围的卵丘细胞,在卵母细胞体外成熟及早期胚胎发育过程中始终有表达,且在囊胚中表达最高。Gas6 mRNA在卵母细胞成熟过程中始终存在,但在孤雌激活后迅速消失,直到发育到囊胚时再次出现。在猪卵母细胞体外培养系统中添加不同浓度的Gas6重组蛋白培养卵母细胞,发现添加Gas6重组蛋白对卵母细胞的极体率无显著影响;但是当添加浓度为100 ng/mL时,培养的卵母细胞孤雌激活后分裂率、囊胚率及囊胚细胞数都显著增高。Gas6可能是通过改善卵母细胞细胞质的成熟质量提高卵母细胞的发育潜能,从而获得了更多、更好的胚胎。     

不同直径山羊卵泡卵母细胞的发育特征及体外发育能力

目的研究山羊卵巢表面不同直径卵泡卵母细胞的发育特征及体外发育能力,优化山羊早期胚胎体外生产系统。方法收集繁殖期和非繁殖期山羊卵巢,采集表面直径小于1.5 mm、1.5-2.5 mm、2.5-3.5 mm和大于3.5 mm4种卵泡卵母细胞,以Hoechst33342染色检查核发育阶段;同时,利用体外培养方法观察不同直径卵泡卵母细胞的成熟、受精和早期胚胎发育能力。结果直径小于1.5 mm卵泡卵母细胞主要处于GVI期;1.5-2.5 mm卵泡卵母细胞以GVⅠ、GVⅡ和GVⅢ期为主;2.5-3.5 mm卵泡卵母细胞在GVⅡ到GVⅣ期间平均分布;大于3.5mm卵泡卵母细胞主要为GVⅢ到GVBD期。体外培养实验发现,直径小于1.5 mm卵泡卵母细胞仅有个别能完成成熟和卵裂;大于1.5 mm卵泡卵母细胞具有核成熟能力,能完成成熟和受精,但1.5-2.5 mm卵泡卵母细胞的受精卵通常阻滞于4-8细胞期;当卵泡直径大于2.5 mm时,卵母细胞才能较好地支持胚胎继续发育,其桑/囊胚的比例达到30%以上。卵泡卵母细胞的发育特征和体外发育能力与动物所处的繁殖季节无关。结论山羊卵巢上直径大于1.5 mm卵泡卵母细胞具有核成熟能力,大于2.5 mm卵泡卵母细胞能支持早期胚胎继续发育。     

一氧化氮供体硝普纳对小鼠卵母细胞体外自发成熟的影响

目的　探讨一氧化氮供体—硝普纳 (SodiumNitroprusside ,SNP)对昆明小鼠卵母细胞体外自发成熟的影响。方法　利用体外培养方法 ,在培养的不同时间观察卵母细胞的成熟情况 ,研究SNP对卵母细胞自发成熟的动力学影响。结果　 (1) 1mmol LSNP能够明显延迟卵丘卵母细胞复合体 (CEOs)的自发成熟 ,与对照组相比 ,CEOs的生发泡破裂 (GVBD)和第一极体 (PB1)释放分别延迟了 8h和 10h。但在培养结束 (2 4h)时 ,CEOs处理组的PB1释放率与对照组相比有明显的降低 ,而处理组的生发泡破裂 (GVBD)百分率和对照组相比没有明显变化 ;1mmol LSNP能够明显延迟裸卵母细胞 (DOs)的自发成熟 ,与对照组相比 ,DOs处理组的GVBD和PB1释放分别延迟了 6h和 12h。且在培养 2 4h后 ,DOs处理组的GVBD和PB1释放率与对照组相比有显著的降低。 (2 ) 1mmol LSNP能够明显促进CEOs中卵丘细胞的离散 ,造成CEOs互相粘连在一起。 (3) 1mmol LSNP能够明显影响体外培养的DOs的形态 ,但对CEOs的卵母细胞却没有影响。而 1μmol LSNP对CEOs和DOs的自发成熟都没有影响。 结论高浓度的SNP对小鼠卵母细胞体外自发成熟有抑制作用     

Ultrastructure of the vitelline follicles of Gorgoderina vitelliloba (Trematoda: Gorgoderidae)

An electron microscope study of the vitelline follicles of Gorgoderina vitelliloba indicates that they contain vitelline cells in various stages of development. Juvenile cells are small and characterised by a little cytoplasm. During differentiation a large amount of granular endoplasmic reticulum develops. In more mature cells, indistinct Golgi complexes give rise to globules of shell protein which migrate to form clusters at the periphery of the cell. Further maturation results in the appearance of large lipid bodies in the vitelline cell cytoplasm.Developing vitelline cells are ensheathed by nurse cell cytoplasm containing numerous small vacuoles which appear to be derived from smooth endoplasmic reticulum. It is suggested that nurse cells may have a role in selection and transport of nutrient material for vitelline cells and that they manufacture precursors of lipid which is subsequently stored as a food reserve in mature vitelline cells. Possible transport sites between parenchymal cells and nurse cells were identified.     

Ultrastructural Observations on the Gametocytic Stages of the Coccidium Tyzzeria chalcides Probert, Roberts & Wilson, 1988 from the Ocellated Skink Chalcides ocellatus

Gametogenesis of Tyzzeria chalcides Probert, Roberts & Wilson, 1988, from the ocellated skink, Chalcides ocellatus , occurs within the epithelium of the gali bladder. Transmission electron microscopy reveals that macrogamonts contain 2 types of wall-forming bodies. Type I bodies are large densely stained structures associated with rough endoplasmic reticulum and the Golgi apparatus. They appear to be formed within the Golgi itself. Type II bodies are less densely stained, smaller and appear to form directly from the rough endoplasmic reticulum. Canaliculi are associated with Type I wall-forming bodies and probably function to transport the wall-forming bodies to the pellicle. Micropores occur in the pellicie and large amylopectin granules, lipid globules and dense bodies are found within the cytoplasm of the macrogamont. Mature microgamonts contain in excess of 20 microgametes, each of which has 2 flagella and an associated mitochondrion. Both types of gamont are found within a parasitophorous vacuole, in the host cell, which is filled with vesicular material on which the gamonts probably feed.     

The female gonad in two species of Microplana (Platyhelminthes,Tricladida, Rhynchodemidae): Ultrastructural and cytochemical investigations

The female gonad of the land planarians Microplana scharffi and Microplana terrestris consists of two small germaria located ventrally in the anterior third of the body and of two ventro‐lateral rows of oblong vitelline follicles distributed between the intestinal pouches. Both these structures are enveloped by a tunica composed of an outer extracellular lamina and an inner sheath of accessory cells. Oocyte maturation is characterized by the appearance of chromatoid bodies and the development of endoplasmic reticulum and Golgi complexes. These organelles appear to be correlated with the production of egg granules with a fenestrated/granular content of medium electron density, about 4–5 μm in diameter, which remain dispersed in the ooplasm of mature oocytes. On the basis of cytochemical tests showing their glycoprotein composition, and their localization in mature oocytes, these egg granules have been interpreted as yolk. In the vitelline follicles, vitellocytes show the typical features of secretory cells with well‐developed rough endoplasmic reticulum and Golgi complexes involved in the production of eggshell globules and yolk. The eggshell globules, which appear to arise from repeated coalescences of two types of Golgi‐derived vesicles, contain polyphenols and, when completely mature, they measure about 1–1,2 μm in diameter and show a meandering/concentric content pattern as is typical of the situation observed in most Proseriata and Tricladida. Mature vitellocytes also contain a large amount of glycogen and lipids as further reserve material. On the basis of the ultrastructural features of the female gonad and in relation to the current literature the two species of rhynchodemids investigated appear to be closely related to the freshwater planarians belonging to the family Dugesiidae. J. Morphol. 2009. © 2009 Wiley‐Liss, Inc.     

Ultrastructure of Pharyngostomoides procyonis Harkema 1942 (Diplostomatidae). II. The female reproductive system

Several components of the female reproductive system of Pharyngostomoides procyonis, including the vitellaria and vitelline duct, ovary and oviduct, Laurer's canal, and Mehlis' gland and associated ducts, were observed with the electron microscope. Vitelline follicles contain cells in various stages of development. Mature vitelline cells contain membrane-delimited clusters of vitelline globules near the plasma membrane. Cilia are present in the vitelline duct. The ovary contains germ cells in various stages of maturation. Oogonia are found in the peripheral region. Mature oocytes contain numerous dense bodies near the plasmalemma. Also included in the cytoplasm of mature oocytes are "nucleolus-like bodies," myelin-like bodies, and mitochondria containing dense granules and few cristae. The epithelium of the oviduct is ciliated. Sperm are present in the oviduct and in Laurer's canal. Two types of secretory cells found in Mehlis' gland are described.     

Structure of taste buds in foliate papillae of the rhesus monkey, Macaca mulatta

Taste buds in foliate papillae of the rhesus monkey were examined by electron microscopy. Three distinct cell types were identified. Type I cells were narrow elongated cells containing an oval nucleus, bundles of intermediate filaments, several Golgi bodies, and characteristic apical membrane-bounded dense granules. These cells exhibited morphological variations: some had a moderately dense cytoplasm, perinuclear free ribosomes, and flattened sacs of rough endoplasmic reticulum; others had a more lucent cytoplasm, dilated irregular rough endoplasmic reticulum, lysosome-like dense bodies, and lipid droplets. Type II cells typically contained a spherical, pale nucleus, a prominent nucleolus, supranuclear and infranuclear Golgi bodies, mitochondria with tubular cristae, and one or two centrioles. This cell type, too, showed some variation in the relative amounts of ribosomes and smooth endoplasmic reticulum, which varied inversely with each other. Type III cells were characterized by a clear apical cytoplasm essentially devoid of ribosomes and containing microtubules. In a few type III cells, the peri- and infranuclear regions contained many ribosomes and some rough endoplasmic reticulum. In most Type III cells, there were large numbers of dense and clear vesicles in the peri- and infranuclear regions; some of the vesicles were grouped in synapse-like arrangements with adjacent nerves. The morphological variations exhibited by all three cell types could be accounted for by age differences in each of the cells. This would be consistent with the notion that cell renewal occurs in each of the three cell populations.     

Ultrastructural and cytochemical aspects of the female gonad of Geoplana burmeisteri (Platyhelminthes, Tricladida, Terricola)

The ultrastructure of the female gonad of the land planarian Geoplana burmeisteri was investigated by means of electron microscopy and cytochemical techniques. It consists of two small germaria located ventral to the intestine and of two irregular, lateral rows of vitelline follicles, both enveloped by a tunica composed of an extracellular lamina and an inner sheath of accessory cells. Accessory cell projections completely surround developing oocytes and vitellocytes. The main feature of oocyte maturation is the appearance of chromatoid bodies and the development of the rough endoplasmic reticulum (RER) and Golgi complexes. These organelles appear to be correlated with the production of egg inclusions of medium electron density, about 1.5-1.8 microm in diameter, which remain scattered in the ooplasm of mature oocytes. On the basis of cytochemical tests demonstrating their glycoprotein composition, these inclusions were interpreted as residual yolk globules. Vitellocytes are typical secretory cells with well-developed RER and Golgi complexes that are mainly involved in the production of yolk globules and eggshell globules, respectively. Eggshell globules appear to arise from repeated coalescence of small Golgi-derived vesicles and, at an intermediate stage of maturation, show a multigranular pattern. Later, after vesicle fusion, they reach a diameter of 1.3-1.6 microm when completely mature and show a meandering/concentric pattern, as is typical of the situation seen in most Proseriata and Tricladida. The content of yolk globules is completely digested by pronase, while the content of eggshell globules is unaffected. Mature vitellocytes contain, in addition, a large quantity of glycogen and lipid droplets as further reserve material. On the basis of the ultrastructural characteristics of the female gonad described above and in relation to the current literature, we conclude that G. burmeisteri appears to be more closely related to the freshwater triclads, in particular to members of the Dugesiidae, than to the marine triclads.     

Oogenesis in the terrestrial hermit crab Coenobita clypeatus (decapoda,anomura). I. Previtellogenic oocytes

Ultrastructural study of previtellogenic oocytes found in cystlike clusters scattered throughout the length of the bilobed ovary of the hermit crab Coenobita clypeatus shows a high nuclear:cytoplasm ratio. Large, round nuclei containing synaptinemal complexes serve as good temporal markers for identification of previtellogenic oocytes. The cytoplasm contains many smooth-membraned vesicles filled with granules and probably of nuclear origin. In addition to its complement of Golgi complexes, endoplasmic reticulum, mitochondria, and free ribosomes, the cytoplasm also contains stacks of annulate lamellae, a feature not previously described for decapod oocytes. Typically, the previtellogenic oocyte with its accumulation of ribosomes has the appearance of a nonsynthetic cell preparing to go through a metabolic transition.     

凡纳滨对虾卵母细胞卵黄发生的超微结构

利用电镜研究凡纳滨对虾卵母细胞卵黄发生的全过程。结果表明 :凡纳滨对虾卵黄的发生是双源性的。卵黄发生早、中期是内源性卵黄大量合成的阶段 ,卵黄发生中、后期则以外源性卵黄的合成为主。内源性卵黄主要由内质网、线粒体、核糖体、溶酶体、高尔基器等多种胞器活跃参与形成。其中数量众多的囊泡状粗面内质网是形成内源性卵黄粒的最主要的细胞器 ;部分线粒体参与卵黄粒的合成并自身最终演变为卵黄粒 ;丰富的游离核糖体合成了大量致密的蛋白质颗粒并在卵质中直接聚集融合成无膜的卵黄粒 ;溶酶体通过吞噬、消化内含物来形成卵黄粒和脂滴 ,且方式多样 ;高尔基器不直接参与形成卵黄粒。外源性卵黄主要通过卵质膜的微吞饮活动从卵周隙或卵泡细胞中摄取外源物质来形成