长江华溪蟹卵子发生的细胞化学研究

利用细胞化学的方法，对长江华溪蟹卵子发生过程中，核酸、蛋白质、糖类及脂类的变化进行了研究，结果表明：核酸从卵原细胞到卵母细胞的发育进程中逐渐分散；蛋白质的量不断增加；脂类物质也在慢慢积累，伴随着发育，在成熟的卵母细胞质内充满ＰＡＳ阳性反应的卵黄颗粒。     

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。     

华鲮受精早期的电镜观察

采用扫描和透射电镜观察了华鲮(Sinilabeo rendahli)成熟卵子、精子的形态特征和精子入卵的过程。结果显示:华鲮成熟卵子直径1.2 mm左右,仅有一个受精孔,卵膜表面有大量的不规则褶皱,精孔器表面平整;成熟精子全长约30μm,头部圆形无顶体;授精1 s精子大量附着于精孔器周围,仅有一个精子进入卵中,授精30~60 s受精孔内形成“受精栓”,精子开始溶解,卵膜逐渐隆起,褶皱消失。     

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。     

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。     

屠宰绵羊卵巢卵母细胞的体外培养成熟

[目的] 探索把屠宰母羊卵巢卵母细胞在体外条件下培养成熟的有效处理方法和条件以便为体外受精技术的研究提供更多的成熟卵子。 [方法] 把从屠宰母羊新鲜卵巢的发育卵泡中采集的784枚卵母细胞分为3种类型,即A型(卵丘细胞层较完整的卵子)、B型(卵丘细胞层部分脱落的卵子)和C型(卵丘细胞、放射冠均脱落的裸卵)。并     

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。     

稀有Ju鲫产卵频次和卵子发育的研究

对室养条件下２０尾雌性稀有Ｊｕ鲫的产卵频次,成熟卵巢卵径分布及卵子补充过程进行了研究,产卵间隔中卵径分布呈现不同的峰值,卵母细胞成熟是分批的,Ｖ期卵巢中ＭＡ,ＲＥ卵母细胞的数量代表了即将进行的一次产卵的产卵量;卵子补充速度快,成熟卵巢每隔数天可发育成熟一批卵,一级贮备库在１２－３３ｄ即更新一次,不同发育时期卵母细胞的补充是连续的,对２７３批Ｊｕ产卵进行了统计,每尾鲫鱼平均４．５ｄ产卵一次,平均批产     

稀有鮈鲫产卵频次和卵子发育的研究

对室养条件下20尾雌性稀有鮈鲫的产卵频次、成熟卵巢卵径分布及卵子补充过程进行了研究。产卵间隔中卵径分布呈现不同的峰值,卵母细胞成熟是分批的,Ⅴ期卵巢中MA、RE卵母细胞的数量代表了即将进行的一次产卵的产卵量;卵子补充速度快,成熟卵巢每隔数天可发育成熟一批卵,一级贮备库在12─33d即更新一次,不同发育时期卵母细胞的补充是连续的。对273批鮈产卵进行了统计,每尾雌鱼平均4.5d产卵一次,平均批产卵量265.6粒。稀有鮈鲫的产卵类型为连续产卵类型。       

三疣梭子蟹卵子发生的研究

１９８９年９月－１９９１年１月、作者利用透射电镜在超微结构水平研究了浙江舟山沿海的三疣梭蟹的卵子发生过程。实验结果得自于１２次取得的１５０号样品。根据核和胞质的变化我们把该蟹的卵子发生分为五期；卵原细胞分裂转化为卵原细胞；卵母细胞发育早期；卵母细胞发育中期；卵母细胞发育晚期；卵子形成期。     

Fine Structure of the Ovarian Development in the Orb-web Spider, Nephila clavata

ABSTRACT Fine structural changes of the ovary and cellular composition of oocyte with respect to ovarian development in the orb-web spider, Nephila clavata were examined by scanning and transmission electron microscopy. Unlike the other arthropods, the ovary of this spider has only two kinds of cells-follicle cells and oocytes. During the ovarian maturation, each oocyte bulges into the body cavity and attaches to surface of the elongated ovarian epithelium through its peculiar short stalk attachments. In the cytoplasm of the developing oocyte two main types of yolk granules, electron-dense proteid yolk and electron-lucent lipid yolk granules, are compactly aggregated with numerous glycogen particles. The cytoplasm of the developing oocyte contains a lot of ribosomes, poorly developed rough endoplasmic reticulum, mitochondria and lipid droplets. These cell organelles, however, gradually degenerate by the later stage of vitellogenesis. During the active vitellogenesis stage, the proteid yolk is very rapidly formed and the oocyte increases in size. However, the micropinocytosis invagination or pinocytotic vesicles can scarcely be recognized, although the microvilli can be found in some space between the oocyte and ovarian epithelium. During the vitellogenesis, the lipid droplets in the cytoplasm of oocytes increase in number, and become abundant in the peripheral cytoplasm close to the stalks. On completion of the yolk formation the vitelline membrane, which is composed of an inner homogeneous electron-lucent component and an outer layer of electron-dense component is formed around the oocyte.     

拟环纹豹蛛产卵前后卵巢组织学及酯酶同工酶的比较研究

利用解剖学和组织切片技术,对拟环纹豹蛛产卵前后卵细胞和卵巢发育的组织学进行了研究。根据细胞核以及核仁的形态及卵黄积累等情况,将卵细胞的发育分成4个时期：卵原细胞、卵黄合成期的卵母细胞、成熟前期和成熟期。观察发现,拟环纹豹蛛的卵巢南若干向卵巢腔内突起的卵巢小体构成,卵巢发育随着卵细胞的发育有一定的规律性。利用聚丙烯酰胺凝胶电泳的方法研究了产卵前后和未成熟不同时期的卵巢酯酶同工酶,结果发现同工酶存在一定差异。     

莫桑比克非鲫卵黄形成的电镜观察

运用透射电镜观察了莫桑比克非鲫卵母细胞的生长.根据卵母细胞的大小和内部结构特征,将其分为四个时期:卵母细胞生长早期:卵黄泡形成期:卵黄积累期:卵黄积累完成期.本文着重研究了主要卵黄成分--卵黄球的形成过程.卵黄球属外源性卵黄,由卵母细胞通过微胞饮作用吸收肝脏合成的卵黄蛋白原后形成的.在卵黄大量积累前,卵母细胞内的线粒体和多泡体聚集成团,构成卵黄核,继而线粒体大量增殖,线粒体形状发生改变,形成同心多层膜结构,为大量的卵黄物质积累提供场所.最终形成的卵黄球由被膜、卵黄结晶体和两者之间的非结晶区三部分组成.       

Regulation of the vitellogenin receptor during Drosophila melanogaster oogenesis

In many insects, development of the oocyte arrests temporarily just before vitellogenesis, the period when vitellogenins (yolk proteins) accumulate in the oocyte. Following hormonal and environmental cues, development of the oocyte resumes, and endocytosis of vitellogenins begins. An essential component of yolk uptake is the vitellogenin receptor. In this report, we describe the ovarian expression pattern and subcellular localization of the mRNA and protein encoded by the Drosophila melanogaster vitellogenin receptor gene yolkless (yl). yl RNA and protein are both expressed very early during the development of the oocyte, long before vitellogenesis begins. RNA in situ hybridization and lacZ reporter analyses show that yl RNA is synthesized by the germ line nurse cells and then transported to the oocyte. Yl protein is evenly distributed throughout the oocyte during the previtellogenic stages of oogenesis, demonstrating that the failure to take up yolk in these early stage oocyte is not due to the absence of the receptor. The transition to the vitellogenic stages is marked by the accumulation of yolk via clathrin-coated vesicles. After this transition, yolk protein receptor levels increase markedly at the cortex of the egg. Consistent with its role in yolk uptake, immunogold labeling of the receptor reveals Yl in endocytic structures at the cortex of wild-type vitellogenic oocytes. In addition, shortly after the inception of yolk uptake, we find multivesicular bodies where the yolk and receptor are distinctly partitioned. By the end of vitellogenesis, the receptor localizes predominantly to the cortex of the oocyte. However, during oogenesis in yl mutants that express full-length protein yet fail to incorporate yolk proteins, the receptor remains evenly distributed throughout the oocyte.     

Ultrastructure of oogenesis in the bluefin tuna, Thunnus thynnus

Ovarian ultrastructure of the Atlantic bluefin tuna (Thunnus thynnus) was investigated during the reproductive season with the aim of improving our understanding of the reproductive biology in this species. The bluefin, like the other tunas, has an asynchronous mode of ovarian development; therefore, all developmental stages of the oocyte can be found in mature ovaries. The process of oocyte development can be divided into five distinct stages (formation of oocytes from oogonia, primary growth, lipid stage, vitellogenesis, and maturation). Although histological and ultrastructural features of most these stages are similar among all studied teleosts, the transitional period between primary growth and vitellogenesis exhibits interspecific morphological differences that depend on the egg physiology. Although the most remarkable feature of this stage in many teleosts is the occurrence of cortical alveoli, in the bluefin tuna, as is common in marine fishes, the predominant cytoplasmic inclusions are lipid droplets. Nests of early meiotic oocytes derive from the germinal epithelium that borders the ovarian lumen. Each oocyte in the nest becomes surrounded by extensions of prefollicle cells derived from somatic epithelial cells and these form the follicle that is located in the stromal tissue. The primary growth stage is characterized by intense RNA synthesis and the differentiation of the vitelline envelope. Secondary growth commences with the accumulation of lipid droplets in the oocyte cytoplasm (lipid stage), which is then followed by massive uptake and processing of proteins into yolk platelets (vitellogenic stage). During the maturation stage the lipid inclusions coalesce into a single oil droplet, and hydrolysis of the yolk platelets leads to the formation of a homogeneous mass of fluid yolk in mature eggs.     

Characterization and expression of the putative ovarian lipoprotein receptor in the Kuruma prawn, Marsupenaeus japonicus

Ovarian low density lipoproteins (LDL) such as vitellogenin (Vg) are the precursors of the major yolk protein vitellin, and constitute the major source of nutrients serving the developing embryo. The objective of this study was to gain a better understanding of crustacean egg development by focusing on the process of Vg internalization by its receptor (ovarian LDLR). First, an ovarian LDLR cDNA sequence in Marsupenaeus japonicus was determined. Ovarian LDLR mRNA expression was then examined, and was seen to be specific to the ovary, exhibiting highest levels during the previtellogenic stage. This pattern of ovarian LDLR expression is thought to signify preparation for yolk protein incorporation into the oocyte. Using immunoblotting techniques, an ovarian LDLR band was detected whose size was similar to that estimated from the deduced amino acid sequence. The ovarian LDLR protein was expressed only at the onset of vitellogenesis, and histological studies supported these observations. This is the first occasion that the ovarian LDLR and its expression dynamics during vitellogenesis have been fully characterized in a crustacean.     

Morphology and ultrastructure of the adult ovarian cycle in Mithracidae (Crustacea,Decapoda, Brachyura,Majoidea)

The ultrastructure of the ovary during development and yolk production is poorly known in Brachyura and Majoidea in particular. Here, we describe the histology, histochemistry and ultrastructure of the adult ovarian cycle in four Mithracidae species from three different genera: Mithrax hispidus, Mithrax tortugae, Mithraculus forceps and Omalacantha bicornuta. All species showed a similar pattern of ovarian development and vitellogenesis. Macroscopically, we detected three stages of ovarian development: rudimentary (RUD), developing (DE) and mature (MAT); however, in histological and ultrastructural analyses, we identified four stages of development. The oocytes of the RUD stage, during endogenous vitellogenesis, have basophilic cytoplasm filled with dilated rough endoplasmic reticulum. The reticulum lumen showed many granular to electron-dense materials among the different stages of development. The Golgi complexes were only observed in the RUD stage and are responsible for releasing vesicles that merge to the endogenous or immature yolk vesicles. At the early DE stage, the oolemma showed many coated and endocytic vesicles at the cortex. The endocytic vesicles merge with the endogenous yolk to form the exogenous or mature yolk vesicles, always surrounded by a membrane, characterizing exogenous vitellogenesis. The exogenous yolk vesicles comprise glycoproteins, showing only neutral polysaccharides. At the late DE stage, endocytosis still occurs, but the amount of endogenous yolk decreases while the exogenous yolk increases. The late DE stage is characterized by the beginning of chorion production among the microvilli. The MAT stage is similar to the late DE, but the endogenous yolk is restricted to a few cytoplasmic areas, the ooplasma is filled with exogenous yolk, and the oolemma has very few coated vesicles. In the MAT stage, the chorion is fully formed and shows two electron-dense layers. The ovarian development of the species studied has many similarities with the very little known Majoidea in terms of the composition, arrangement and increment of the yolk vesicles during oocyte maturation. The main differences are in the vitellogenesis process, where immature yolk formation occurs without the direct participation of the mitochondria but with the participation of the rough endoplasmic reticulum in the endogenous phase.     

The development of oocytes in the ovary of a parthenogenetic tick, Haemaphysalis longicornis

Haemaphysalis longicornis is an important vector of various pathogens in domestic animals and humans. The tick is a unique species with bisexual and parthenogenetic races. Although mating induces oocyte development, it is possible in the parthenogenetic race to complete oogenesis without copulation. Here we examined the developmental process of oocytes from unfed to the oviposition period in parthenogenetic H. longicornis. We classified the developmental stages of oocytes into five stages: stage I, germinal vesicle occupies more than half of the cytoplasm; stage II, germinal vesicle occupies less than half of the cytoplasm; stage III, germinal vesicle migrates from the center in the oocyte to the vicinity of the pedicel cells; stage IV, the cytoplasm is filled with yolk granules of various sizes; stage V, the cytoplasm is occupied by large yolk granules. Oocytes at the unfed period were undeveloped and classified as stage I. Stage I and II oocytes were observed at the rapid feeding period, indicating that oocyte development began after the initiation of blood feeding. All developmental stages of oocytes were observed at the pre-oviposition period. At 10?days after the beginning of the oviposition period, the ratios of stage I and II oocytes were higher than those of the previous period, suggesting that the ovarian development and activity may be continuing. Based on these findings, we propose classification criteria for the oocyte development in the parthenogenetic H. longicornis. The criteria will be useful for understanding the mechanisms of tick reproduction and transovarial transmission of pathogens.     

葛洲坝水利枢纽下游宜昌江段渔业资源现状

1997-1999年间统计了葛洲坝水利枢纽工程下游宜昌江段的不同渔具渔获物3254kg。共获得鱼类45种,优势种类为铜鱼、瓦氏黄颡鱼、长鳍吻鮈、圆筒吻鮈、草鱼、鲢、长吻鮠、南方鲇等,鳊、青鱼、鳡等的相对数量比建坝前减少,(鱼宗)、鳜、鳤、鲌类等建坝前的常见种类现在较为少见或罕见。鲥、裂腹鱼、华鲮、暗纹东方鲀等偶见种类以及珍稀鱼类白鲟未被发现。目前该江段渔获物中低龄个体比重较高,性成熟个体较少。过度捕捞是影响坝下江段渔业资源衰退的主要原因。     

Stages of oocyte development in the zebrafish,Brachydanio rerio

Oocyte development has been divided into five stages in the zebrafish Brachydanio rerio, based on morphological criteria and on physiological and biochemical events. In stage I (primary growth stage), oocytes reside in nests with other oocytes (Stage IA) and then within a definitive follicle (Stage IB), where they greatly increase in size. In stage II (cortical alveolus stage), oocytes are distinguished by the appearance of variably sized cortical alveoli and the vitelline envelope becomes prominent. In stage III (vitellogenesis), yolk proteins appear in oocytes and yolk bodies with crystalline yolk accrue during this major growth stage. Ooctes develop the capacity to respond in vitro to the steroid 17α, 20β-dihydroxy-4-pregnen-3-one (DHP) by undergoing oocyte maturation. In stage IV (oocyte maturation), oocytes increase slightly in size, become translucent, and their yolk becomes non-crystalline as they undergo final meiotic maturation in vivo (and in response to DHP in vitro). In stage V (mature egg), eggs (approx. 0.75 mm) are ovulated into the ovarian lumen and are capable of fertilization. This staging series lays the foundation for future studies on the cellular processes occurring during oocyte development in zebrafish and should be useful for experimentation that requires an understanding of stage-specific events. © 1993 Wiley-Liss, Inc.