九孔鲍卵子发生及卵巢发育的组织学观察

采用组织学方法研究了九孔鲍(Haliotis diversicolor supertexta)的卵子发生、卵巢结构及其发育.根据卵细胞的大小、形状,核仁的形态,卵黄颗粒的积累情况,滤泡的结构等.将九孔鲍卵子的发生分为卵原细胞、卵黄发生前的卵母细胞和卵黄发生期的卵母细胞3个时期;卵巢壁由外膜及内生殖上皮构成,生殖上皮分化产生卵原细胞和滤泡细胞;卵巢的结构单位是滤泡.根据卵巢的外部形态和内部组织结构,将九孔鲍的卵巢发育分为休止期、增殖期、生长期、成熟期和排放期共5期.     

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。       

昆虫卵子发生调控因素的研究进展

动物卵原细胞形成成熟卵细胞的过程称为卵子发生。昆虫卵子发生在卵巢里进行,经历了卵原细胞的增殖、卵母细胞的生长和卵母细胞的成熟三个阶段。在此过程中,昆虫卵子的发生受到很多内外因素的影响,如基因、细胞因子和环境等。卵子的发生影响着成熟卵细胞的质量以及卵细胞与精子的结合。本文就影响昆虫卵子发生的因素进行综述。     

白纹伊蚊卵黄发生的观察

以白纹伊蚊Aedes albopictus为材料,对其卵子发生的卵黄物质形成过程进行了显微观察.结果显示,卵子和卵母细胞的长度变化显著,呈现先平稳后快速增长直至稳定的发育特点;在吸血后31 h内,卵黄物质快速、急剧地在卵母细胞中沉积,至吸血51 h,卵黄物质在卵母细胞中的比例达到峰值(100%).根据卵子中卵母细胞、滋...     

泥螺卵子发生的超微结构研究

利用透射电镜观察了泥螺卵子发生过程。结果表明 ,泥螺的卵子发生可划分为卵原细胞、卵黄发生早期、卵黄发生中期及卵黄发生后期卵母细胞 4个时期。卵原细胞核大而圆 ,胞质内分布有少量的线粒体和高尔基囊泡 ,细胞表面具微绒毛。卵黄发生早期的卵母细胞 ,胞质中各类细胞器发达 ,并出现数量较多的类朦胧子。卵黄发生中期的卵母细胞胞体迅速增大 ,核伸出伪足状突起 ,卵质中各种细胞器活动活跃 ,并参与形成卵黄粒和脂滴。此期还可观察到卵母细胞与滤泡细胞间的物质交换现象。卵黄发生后期的卵母细胞体积增至最大 ,细胞器数量减少。本文就卵黄发生前后卵母细胞内部构造的变化、意义及滤泡细胞与卵母细胞蛋白来源间的关系作了探讨     

泥螺卵子发生的超微结构研究

利用透射电镜观察了泥螺卵子发生过程。结果表明,泥螺的卵子发生可划分为卵原细胞、卵黄发生早期、卵黄发生中期及卵黄发生后期卵母细胞4个时期。卵原细胞核大而圆,胞质内分布有少量的线粒体和高尔基囊泡,细胞表面具微绒毛。卵黄发生早期的卵母细胞,胞质中各类细胞器发达,并出现数量较多的类朦子。卵黄发生中期的卵母细胞胞体迅速增大,核伸出伪足状突出,卵质中各种细胞器活动活跃,并参与形成卵黄粒和脂滴。此期还可观察到卵母细胞与滤泡细胞间的物质交换现象。卵黄发生后期的卵母细胞体积增至最大,细胞器数量减少。本文就卵黄发生前后卵母细胞内部构造的变化、意义及滤泡细胞与卵母细胞蛋白来源间的关系作了探讨。     

北京油葫芦卵子发生中DNA及RNA动态变化研究

用孚尔根及甲基绿 -派洛宁组织化学染色法了解北京油葫芦Teleogryllusmitratus(Burmeister)卵子发生各时期阶段中卵内DNA及RNA动态变化规律。在卵子发生的最初阶段 ,核中DNA的合成和复制最活跃 ,以后便慢慢减弱 ;而RNA则在第 2阶段合成最旺盛。在卵子发生各个阶段 ,滤泡细胞中DNA ,RNA均为阳性反应 ,并在卵细胞的卵黄形成期活动旺盛 ,为卵母细胞卵黄蛋白形成提供物质基础。卵子发生第 4～ 6阶段 ,滤泡细胞开放时期 ,血淋巴内一些物质可能直接或间接通过滤泡细胞间隙进入卵母细胞内 ,参与卵母细胞的发育和构建。研究表明卵子发生初期卵母细胞的发育和物质构建主要以内源性合成积累为主 ,中后期则有外源性物质的参与。     

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。     

隆线溞孤雌溞生殖系统的组织学

隆线孤雌的生殖系统由一对卵巢、一对输卵管和一对雌性生殖孔组成。卵巢长管状 ,管壁由结缔组织膜和单层上皮细胞构成 ,末端渐细为一短小的输卵管 ,输卵管末端为雌性生殖孔。卵子的发生是由生发区细胞向卵巢内增殖分化 ,不同成熟度的生殖细胞在管腔内排列成生殖带。根据卵母细胞细胞核的大小及卵黄的累积情况等 ,将卵子的发生划分为三个时期 :卵原细胞、卵母细胞和成熟卵子 ,其中卵母细胞的发生又可细分为三个时期 :前期、中期和后期。后期的卵母细胞含较多的卵黄颗粒 ,最后成为成熟卵子 ,排入孵育囊内形成夏卵。隆线孤雌的卵巢发育要经历五个幼龄期 ,不同的龄期 ,卵巢的形态结构不同。至第五幼龄 ,卵巢已基本发育成熟 ,准备排卵进入第一成龄     

缠绕蚊蝎蛉雌性生殖系统构造及卵子发生

雌性生殖系统构造及卵子发生过程在探讨昆虫系统发育关系中具有重要意义。本文利用半薄切片法解剖观察了缠绕蚊蝎蛉Terrobittacus implicatus (HuangHua,2006)雌性生殖系统的构造及卵子发生过程。结果表明,缠绕蚊蝎蛉雌虫的卵巢由7根多滋式卵巢管组成,各个卵巢管的大小和长度不同。每个卵巢管可分为端丝、生殖区(原卵区)、生长区(卵黄区)和卵巢管柄4个部分。生长区由5到6个线形排列的卵室组成,每个卵室中有1个卵母细胞和3个滋养细胞。卵子发生可以分为3个时期,即卵黄发生前期、卵黄发生期、以及卵壳形成期。在卵子发生的整个过程中,卵母细胞、滋养细胞及滤泡细胞的形态均有明显变化。     

Calmodulin synthesis and accumulation during oogenesis and maturation of Xenopus laevis oocytes

The calmodulin levels in stage 6 Xenopus oocytes averaged 89 +/- 24 (SD) ng/oocyte and had largely accumulated by stage 3 of oogenesis. From stage 3 to early stage 6, calmodulin levels did not increase further. However, in large stage 6 oocytes (greater than 1.25 mm diam) calmodulin levels again rose to a level as high as 121 ng/oocyte. Calmodulin levels did not change during the maturation of stage 6 oocytes and the results of measurements on animal and vegetal oocyte halves from control and mature oocytes showed no evidence of a redistribution of calmodulin during maturation. Measurements of calmodulin synthesis in stages 1 and 2 oocytes, stage 4 oocytes, and stage 6 oocytes indicated that calmodulin was being synthesized continuously during oogenesis and that the rate of synthesis increased during oogenesis. In stage 1 and 2 oocytes (combined), the synthesis rate was 3.5 pg/hr/oocyte; in stage 4 oocytes it was 48 pg/hr/oocyte, and in large stage 6 oocytes the rate had increased to 160 pg/hr/oocyte. These changes in the rates of synthesis were discussed as they relate to the pattern of calmodulin accumulation during oogenesis.     

Axis formation during Drosophila oogenesis.

Recent advances shed light on the cellular processes that cooperate during oogenesis to produce a fully patterned egg, containing all the maternal information required for embryonic development. Progress has been made in defining the early steps in oocyte specification and it has been shown that progression of oogenesis is controlled by a meiotic checkpoint and requires active maintenance of the oocyte cell fate. The function of Gurken signalling in patterning the dorsal-ventral axis later in oogenesis is better understood. Anterior-posterior patterning of the embryo requires activities of bicoid and oskar mRNAs, localised within the oocyte. A microtubule motor, Kinesin, is directly implicated in localisation of oskar mRNA to the posterior pole of the oocyte.     

Dynamics of the oocyte cortical cytoskeleton during oogenesis in Rhodnius prolixus

The oocyte cortex undergoes dramatic changes during oogenesis in Rhodnius prolixus. Despite numerous studies examining oogenesis in the telotrophic ovariole, none has investigated the ultrastructural details of the oocyte cortex, in particular, the lateral cortical cytoskeleton. Indirect immunofluorescent staining of sections, rhodamine phalloidin staining of whole mounts and scanning and transmission EM of permeabilized and unpermeabilized preparations revealed the dynamic changes of the oocyte cortex from early previtellogenesis through to late vitellogenesis. During early previtellogenesis, oocytes 50-150 mum in length have a smooth oolemma, with no discernible cortical cytoskeleton. During mid to late previtellogenesis (oocytes 150-350 mum in length) a tightly woven network of microfilaments and microtubules forms, excluding mitochondria and Golgi complexes from the lateral cortex. At the onset of vitellogenesis, the follicuiar epithelium becomes patent, and there is an increase in microvilli covering the lateral oocyte surface. The microfilament cores form a discrete pattern that corresponds to the imprint of the follicle cells on the oocyte surface. While the lateral microfilament cytoskeleton becomes more elaborate, the lateral microtubule cytoskeleton diminishes, remaining sparse throughout vitellogenesis. The oocyte cortical cytoskeleton undergoes dramatic changes during oogenesis. These cortical dynamics are intricately related to the cellular and molecular processes that occur during oogenesis.     

Drosophila Rho-kinase (DRok) is required for tissue morphogenesis in diverse compartments of the egg chamber during oogenesis

The Rho-kinases are widely utilized downstream targets of the activated Rho GTPase that have been directly implicated in many aspects of Rho-dependent effects on F-actin assembly, acto-myosin contractility, and microtubule stability, and consequently play an essential role in regulating cell shape, migration, polarity, and division. We have determined that the single closely related Drosophila Rho-kinase ortholog, DRok, is required for several aspects of oogenesis, including maintaining the integrity of the oocyte cortex, actin-mediated tethering of nurse cell nuclei, "dumping" of nurse cell contents into the oocyte, establishment of oocyte polarity, and the trafficking of oocyte yolk granules. These defects are associated with abnormalities in DRok-dependent actin dynamics and appear to be mediated by multiple downstream effectors of activated DRok that have previously been implicated in oogenesis. DRok regulates at least one of these targets, the membrane cytoskeletal cross-linker DMoesin, via a direct phosphorylation that is required to promote localization of DMoesin to the oocyte cortex. The collective oogenesis defects associated with DRok deficiency reveal its essential role in multiple aspects of proper oocyte formation and suggest that DRok defines a novel class of oogenesis determinants that function as key regulators of several distinct actin-dependent processes required for proper tissue morphogenesis.     

中华蚱蜢卵子发生中花生凝集素受体的初步鉴定和发育表达

The distributions of PNA binding glycoconjugates in the plasma membrane of Acrida cinerea Thunberg germ cells were detected using biotin labeled PNA, for better understanding of the formation and changes of glycoconjugates during oogenesis. The ultrastructure of vitellogenesis also was observed by electron microscopy for detection of the origin and track of vitelline material. In the ovary, PNA receptors appeared in the oocyte cytoplasm of the second phases of oogenesis; positive granules gradually increased from the third phase to the fourth, and they exhibited a maximum expression before the vitellogennic stage in the cytoplasm of the oocyte. From the vitellogennic to chorionation stage, positive granules gradually declined. Binding sites on follicle cells were changed with their morphological variation in every stage of oogenesis. The vitelline of A. cinerea formed within the oocyte by degrees. The results suggest that PNA receptors and yolk materials are synthesized by the oocytc at an early period. With the development of the oocyte, some exogeous materials from two sources act as PNA receptors and others take part in vitelline synthesis. One is blood lymph that offers some useful materials to the oocyte directly through follicle cell gaps; the other are follicle cells that produce and transmit some materials to oocyte to support vitellogenesis. In addition, PNA receptors secreted by follicle cells participate in the formation of yolk membrane [ Acta Zoologica Sinica 5 l （5） ： 932 - 939, 2005 ].