秀丽白虾卵母细胞不同发育阶段滤泡细胞的超微结构

用透射电镜技术观察了秀丽白虾(Exopalaemon modestus)不同发育阶段卵巢滤泡细胞的超微结构及其与卵母细胞的联系。随着卵母细胞的发育进程,滤泡细胞经历了发育和退化过程。在卵黄大量发生期,卵母细胞被多层滤泡细胞包绕,血窦伸入层间;滤泡细胞内含有丰富的内质网、高尔基体、线粒体、核糖体及原始卵黄颗粒。在卵子成熟期,滤泡细胞由内向外依次解体,血窦萎缩。这些形态变化支持滤泡细胞具有吸收血液营养、合成并向卵母细胞输送原始卵黄物质的功能的观点。与锯缘青蟹、长毛对虾和中华绒螯蟹的滤泡细胞的作用方式稍有不同。     

短额负蝗卵子发生过程中糖复合物的动态分布

以生物素标记的凝集素(UEA-I、SBA、PNA)为探针,利用凝集素组织化学方法对短额负蝗(Atracto-morphasinensis)卵子发生过程中滤泡细胞和卵母细胞内糖复合物的分布进行了定位研究。结果表明,在卵子发生的各期滤泡细胞和卵母细胞中没有UEA-I受体的表达,SBA和PNA受体以不同的分布模式呈阶段性表达。两者首次出现于卵母细胞生长期,随后PNA受体消失,SBA受体大量表达;在卵黄形成期前期SBA受体和重新出现的PNA受体表达于卵黄颗粒形成部位,卵黄形成期后期两者均为阴性表达;成熟卵子中两种受体又以不同程度重新出现于卵黄膜。两种受体在滤泡细胞内均大量表达。提示,N-乙酰半乳糖胺和半乳糖-β-(1,3)半乳糖胺复合物的修饰和变化与卵母细胞的发育、卵黄物质的形成及滤泡细胞的增殖分化密切相关,卵黄膜上的糖复合物可能与精卵识别有关。     

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。       

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。     

剑尾鱼卵子发生的的组织学观察

应用光学显微镜对卵胎生硬骨鱼类剑尾鱼(Xiphophorus helleri)卵巢的组织结构进行了观察。结果显示,剑尾鱼卵子的发育过程可划分为6个时相。Ⅰ时相的卵母细胞呈原始分化状态,细胞外具一层细胞质膜。Ⅱ时相卵母细胞外不仅具有质膜,而且还包绕一层滤泡细胞。Ⅲ时相和Ⅳ时相的卵母细胞分化明显,胞质内开始积累脂滴和卵黄颗粒。Ⅴ时相为成熟卵子,卵子的卵膜极薄,胞质内含有丰富的脂滴和卵黄。Ⅵ时相卵母细胞进入退化期,滤泡细胞从卵周向中央突入,卵黄被完全吸收,滤泡细胞自身也变得肥大。结果表明,剑尾鱼卵巢中的卵母细胞的发育是不同步的。     

剑尾鱼卵子发生的组织学观察

应用光学显微镜对卵胎生硬骨鱼类剑尾鱼(Xiphophorus helleri)卵巢的组织结构进行了观察。结果显示,剑尾鱼卵子的发育过程可划分为6个时相。Ⅰ时相的卵母细胞呈原始分化状态,细胞外具一层细胞质膜。Ⅱ时相卵母细胞外不仅具有质膜,而且还包绕一层滤泡细胞。Ⅲ时相和Ⅳ时相的卵母细胞分化明显,胞质内开始积累脂滴和卵黄颗粒。Ⅴ时相为成熟卵子,卵子的卵膜极薄,胞质内含有丰富的脂滴和卵黄。Ⅵ时相卵母细胞进入退化期,滤泡细胞从卵周向中央突入,卵黄被完全吸收,滤泡细胞自身也变得肥大。结果表明,剑尾鱼卵巢中卵母细胞的发育是不同步的。     

北京油葫芦卵黄物质形成的超微结构观察

以蟋蟀科的北京油葫芦Teleogryllusmitratrus(Burmeister)为材料 ,对其卵子发生的卵黄物质形成过程的超微结构进行了观察。根据电镜观察结果分析 ,北京油葫芦卵黄构成有卵母细胞内部物质与外部物质参与。卵黄发生初期 ,主要以卵母细胞自身合成为主 ,随着卵母细胞发育的进行 ,有外源物质介入卵黄合成之中。它包括两部分物质来源 :一部分是由血淋巴通过滤泡细胞间隙向卵母细胞提供合成卵黄物质 ;另一部分则由滤泡细胞通过指状微绒毛以多泡小体和多片小体的形式向卵母细胞提供合成卵黄的物质。     

南方鲶卵巢滤泡细胞和卵膜生成的组织学研究

南方鲶的卵巢滤泡细胞源于卵巢基质细胞,从发生到退化分为零散卵泡膜细胞期、单层扁平泡膜细胞期、多层扁平卵泡膜细胞期、立方形颗粒细胞期柱状颗粒细胞期、颗粒细胞分泌期和颗粒细胞退化期。精孔细胞中发育中滤泡细胞分化形成。初级卵精源于卵母细胞,次级卵膜由晚期滤泡细胞分泌形成。本文还对滤泡细胞和卵膜的作用进行了阐述。     

短额负蝗卵子发生过程中糖复合物的动态分布

以生物素标记的凝集素(UEA-I、SBA、PNA)为探针，利用凝集素组织化学方法对短额负蝗(Atractomorpha sinensis)卵子发生过程中滤泡细胞和卵母细胞内糖复合物的分布进行了定位研究。结果表明，在卵子发生的各期滤泡细胞和卵母细胞中没有UEA-I受体的表达，SBA和PNA受体以不同的分布模式呈阶段性表达。两者首次出现于卵母细胞生长期， 随后PNA受体消失，SBA受体大量表达；在卵黄形成期前期SBA受体和重新出现的PNA受体表达于卵黄颗粒形成部位，卵黄形成期后期两者均为阴性表达；成熟卵子中两种受体又以不同程度重新出现于卵黄膜。两种受体在滤泡细胞内均大量表达 提示，N-乙酰半乳糖胺和半乳糖-β-(1，3)半乳糖胺复合物的修饰和变化与卵母细胞的发育、卵黄物质的形成及滤泡细胞的增殖分化密切相关，卵黄膜上的糖复合物可能与精卵识别有关。     

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。     

Effects of estradiol-17beta on germ cell proliferation and DMY expression during early sexual differentiation of the medaka Oryzias latipes

Sex reversal of XY male to functional females was induced by estrogen treatment during the embryonic period in the medaka Oryzias latipes. The present study aimed to examine whether exogenous estrogen (estradiol-17beta; E(2)) affects early sex differentiation, paying particular attention to DMY expression and proliferation activity of germ cells in estrogen treated XY individuals. Our results showed that germ cell number was not affected by E(2) treatment at hatching, and that DMY expression was not suppressed under conditions of sex reversal. Therefore, male differentiation of germ cells, which is triggered by the expression of DMY in the supporting cell lineage, proceeds even in E(2) treated XY individuals until hatching, and early sex differentiation is not altered by estrogen. However, sex reversal occurred after hatching probably because of estrogen remaining in the yolk. Interestingly, DMY expression was also detected in the large follicle layer of E(2 )treated XY ovary. These results suggested that DMY regulates male determination in early embryonic stage but does not suppress female follicle development.     

大阪鲫鱼两种卵黄蛋白免疫细胞化学的研究

以电泳提纯的卵黄脂磷蛋白和卵黄蛋白Ｌ制备兔抗两种蛋白的抗血清,采用ＰＡＰ法对性腺成熟雌性大阪鲫鱼的肝细胞和卵母细胞进行两种蛋白免疫细胞化学位研究。肝细胞的粗面内质网上有强烈的卵黄脂磷蛋白的阳性反应,特别是在线粒体的基质中也发现卵黄脂磷蛋白的阳性反应,而另外一种类似于卵黄高磷蛋白的卵黄蛋白－卵黄蛋白Ｌ在肝细胞的粗面内质网和线粒体均呈现阴性反应,提示卵黄脂磷蛋白的前体物质存在于肝细胞的粗面内质网和线粒     

瘦露螽配子发生中一氧化氮合酶的分布

利用还原型烟酰胺腺嘌呤二核苷酸(NADPH)黄递酶组织化学方法,对瘦露螽Phaneroptera gracilis Burmeister配子发生中一氧化氮合酶(nitric oxide synthase, NOS)分布进行了定位研究。结果表明, 一氧化氮合酶阳性反应发生在瘦露螽精子发生中的各级生精细胞的胞质中,成熟精子呈阴性。各级未成熟卵母细胞胞质均呈一氧化氮合酶阳性反应,胞质着色为深蓝黑色,核区不明显。随着卵黄颗粒的逐渐形成,胞质中的一氧化氮合酶阳性产物逐渐减少,直到卵黄颗粒完全形成。卵泡细胞在卵黄颗粒形成之前呈一氧化氮合酶阴性反应,在卵黄颗粒完成后,卵泡细胞的胞质中开始呈一氧化氮合酶阳性反应,直至卵壳的形成。提示一氧化氮参与了瘦露螽配子发生。     

扬子鳄卵巢性类固醇激素受体的免疫细胞化学研究

为探讨扬子鳄卵巢内不同性类固醇激素受体在卵泡发育中的调控作用,研究采用组织学和免疫细胞化学方法,运用激光共聚焦显微镜,对扬子鳄不同发育时期卵泡中的雌激素受体、雄激素受体和孕激素受体进行了检测。结果发现,3种类固醇激素受体在卵巢各期滤泡细胞中均有表达,在4月Ⅱ-Ⅳ期卵泡的滤泡细胞中阳性反应最强;9月卵巢的滤泡细胞中阳性反应最弱;ER和AR不仅在各期滤泡细胞中存在阳性位点,在6月卵泡的卵母细胞胞质中也有表达。结果说明,在扬子鳄卵母细胞生长发育和成熟过程中,3种激素受体通过与其对应的激素结合对滤泡细胞的发育、卵黄的合成与积累以及排卵起着重要的调控作用。       

Distribution of yolk polypeptides in the follicle cells during the differentiation of the follicular epithelium in Sarcophaga bullata egg follicles

In S. bullata, the ovaries contribute to the synthesis of yolk polypeptides. A specific antiserum for yolk polypeptides was used to visualize the presence of yolk polypeptides in the follicle cells during their differentiation. After vitellogenesis has started, all follicle cells contain yolk polypeptides. The squamous follicle cells covering the nurse cells and the border cells lose yolk polypeptides before mid-vitellogenesis, whereas the follicle cells over the oocyte contain yolk polypeptides until after late vitellogenesis. All follicle cells are immunonegative afterwards. In vitro translation of poly(A)+ RNA demonstrated that the presence of yolk polypeptide mRNA correlates well with follicle cell immunopositivity for yolk polypeptides. This suggests that the follicle cells synthesize the ovarian yolk polypeptides. Differences in cellular and nuclear morphology, total and poly(A)+ RNA synthesis and the rate of yolk polypeptide synthesis were shown to be correlated with the presence or absence of yolk polypeptides in the differentiating follicular epithelium. The possible relationship between these different aspects of follicle cell differentiation, follicle cell polyploidy and the extracellular current pattern around follicles are discussed.     

Regression in the ovary of Myxine glutinosa L. (Cyclostomata) II. Electron microscope studies of atretic follicles

In the atretic follicle of the open involutionary type an opening in the wall of the follicle is formed through which granulosa cells and yolk platelets are emitted. Migrating cells of the theca layer invade the follicular lumen and absorb phagocytotically residues of granulosa cells. On the other hand, atretic follicles of the closed involutionary type show yolk platelets which remain in the follicular lumen and are dissolved there. The granulated residue of the yolk platelets and the residue of the granulosa cells are absorbed phagocytotically by migrating cells. The follicular atresia of both degenerating types can be regarded as a process exclusively devoted to the purpose of resorbing atretic oocytes. No indications for the production of steroid hormones were found.     

The ultrastructure of oogenesis and yolk formation in Labidocera aestiva (Copepoda: Calanoida)

Yolk formation in the oocytes of the free-living, marine copepod, Labidocera aestiva (order Calanoida) involves both autosynthetic and heterosynthetic processes. Three morphologically distinct forms of endogenous yolk are produced in the early vitellogenic stages. Type 1 yolk spheres are formed by the accumulation and fusion of dense granules within vesicular and lamellar cisternae of endoplasmic reticulum. A granular form of type 1 yolk, in which the dense granules within the cisternae of endoplasmic reticulum do not fuse, appears to be synthesized by the combined activity of endoplasmic reticulum and Golgi complexes. Type 2 yolk bodies subsequently appear in the ooplasm but their formation could not be attributed to any particular oocytic organelle. In the advanced stages of vitellogenesis, a single narrow layer of follicle cells becomes more developed and forms extensive interdigitations with the oocytes. Extra-oocytic yolk precursors appear to pass from the hemolymph into the follicle cells and subsequently into the oocytes via micropinocytosis. Pinocytotic vesicles fuse in the cortical ooplasm to form heterosynthetically derived type 3 yolk bodies.     

A light and electron microscope study on oogenesis in the freshwater pulmonate snail Biomphalaria glabrata

In the freshwater snail Biomphalaria glabrata the formation and composition of yolk granules and the role of the follicle cells were studied by histochemical and electron microscopical techniques. The rough endoplasmic reticulum and the Golgi apparatus appeared to be involved in yolk formation, which is a continuous process throughout oogenesis. From the very beginning of yolk formation two main types of yolk granules were distinguished morphologically. However, with histochemical and enzyme cytochemical methods no differences were observed between these types. The granules acquire lysosomal enzymes after oviposition, indicating that their main function is probably digestion of perivitelline fluid, which contains nutrients for the developing embryo.Yolk formation and the activity of the follicle cells were studied in successive stages of oogenesis by quantitative electron microscopy. The data strongly suggest that the follicle cells are involved in the formation of the follicular cavity and hence in the ovulation process.     

Ultrastructural evidence for both autosynthetic and heterosynthetic yolk formation in the oocytes of an annelid (Phragmatopoma lapidosa: Polychaeta).

The ovaries of the reef-building polychaete Phragmatopoma lapidosa are attached to the genital blood vessels on the caudal surface of the intersegmental septa of the abdominal segments. Oogenesis is not synchronized and vitellogenesis occurs before the oocytes are released from the ovary into the coelomic cavity. A portion of each developing oocyte rests on the basal lamina of the genital blood vessel while the remaining surface of the oocyte is covered by follicle cells. Two morphologically distinct types of yolk are formed during vitellogenesis: Type I, which may be formed autosynthetically by the conjoined efforts of the rough ER and Golgi systems; and Type II, which is presumably formed heterosynthetically from endocytosis of yolk precursors from the genital blood vessel. Heterosynthetic production of yolk in an annelid has not been reported previously.