中华鲟受精细胞学研究

中华鲟(Acipenser sinensis Gray)的成熟卵具有一层放射膜及二层卵黄膜。在动物极有9—15个受精孔。每一受精孔有一大的入口(12.7—13.9μm直径)及一细长的受精管道(1.2—1.3μm直径)。 进入受精孔的许多精子只能按序入卵。其中只有一个精子的头部膨大核化,最后形成雄性原核。同时活跃的卵子也形成雌性原核。雌、雄原核彼此接触,最后融合成合子核,随后分成两个子核。 中华鲟的受精方式为多精入卵,单精受精。     

中华绒螯蟹的受精生物学（一）

中华绒螯蟹的精子无尾部,不能运动;其成熟卵为初级卵母细胞,无受精孔,精子可在卵的任何部位穿入卵内,精子入卵主要借顶体反应。虽多精着卵,但仅数精入卵,且单精受精。     

红鲫与湘江野鲤杂交的受精细胞学研究

红鲫成熟卵直径680—720μm;卵膜孔为精子入卵的唯一通道,包括前庭和精孔管两部分;精孔管内径约5μm。湘江野鲤精子头部直径约2.5μm。在通常情况下,红鲫卵为单精受精。尽管红鲫与湘江野鲤不同属,但杂交仍具有正常的受精细胞学程序。红鲫卵子处于第二次成熟分裂中期接受湘江野鲤精子入卵,精子入卵5min后,出现明显的精子星光;15min后,雄性原核及雌性原核形成;25min后,雌、雄性原核融合;30min后、开始卵裂,发现1个受精卵切片上有4个即将融合的原核,这可能是由于双精受精所致。     

日本鳗鲡精卵的超微结构以及受精过程观察

通过扫描电镜和透射电镜对经人工催产获得的日本鳗鲡(Anguilla japonica)精子、卵膜的超微结构以及受精过程进行了观察。实验观察到,除一般硬骨鱼类的精子特性外,日本鳗鲡精子有其独特的结构。精子头部为不规则的梨形,有背腹面之分。一个巨大的球形线粒体位于头部顶端。精子中段向后伸出一支根,支根位于袖套腔外精子的背侧,前端向精子头部线粒体方向延伸,支根的微管结构为"8+2"结构,并在精子入卵过程中起到切断鞭毛的作用。精子的尾部由鞭毛和鞭毛末端的结组成。鞭毛横切面呈圆形,无侧鳍,鞭毛微管结构为"9+0"结构。受精卵的整个表面密布着无规律延伸的脊、脊包围形成的窝和窝中的孔所组成的脊孔复合体,但无典型特征的受精孔。受精卵超薄切片观察发现,日本鳗鲡卵膜分为外层壳膜和内层卵黄膜。壳膜与卵黄膜间为卵周隙。壳膜只观察到放射带,未见透明带。放射带可分为三个亚层:最外层为脊孔复合体的脊,中间层为皱纹层,最内层为致密的平滑层。脊孔复合体的孔横穿整个放射带,在放射带内层形成一个乳突状结构。日本鳗鲡的卵膜不仅具有保护卵子的作用,而且还参与了受精。实验还通过扫描电镜观察了日本鳗鲡精子的入卵过程。观察结果认为:日本鳗鲡精子入卵过程可分为卵膜对精子的吸引、精子对卵膜的锚定、精核的进入和孔封闭等4个阶段。但由于研究只观察到受精过程中日本鳗鲡精子和卵膜的形态变化,因此对精子穿过卵膜的方式和特征等尚需做进一步的研究。整个受精过程为1min30s左右。此外,研究还探讨了日本鳗鲡精子结构的特殊性和受精过程的特殊性,为进一步突破日本鳗鲡人工育苗技术提供了理论依据。       

唇精子早期入卵观察

用扫描电镜对唇成熟卵子及早期精子入卵过程进行观察.结果 显示,唇成熟卵子在动物极中央有一深凹陷的表面光滑的精孔器,其外径2.512 μm,内径2.330 μm,精子直径1.567 μm.混匀的精卵刚遇水时,没有精子进入精孔器.受精后1 s,精孔器内出现精子.受精后5 s,组织切片显示,精子已经进入卵子内,并形成具有强烈抑制多精入卵作用的受精锥.受精后10 s,精子在精孔器前庭集结,尚未形成受精塞.受精后20 s,在精孔器内形成受精塞.受精塞没有阻塞精孔管,经分析它不是来源于皮层反应产物.受精塞形成后,可以吸附入卵的精子,这对多精入卵有积极的抑制作用;精子尾部在入卵过程中相互缠绕,这也是减少多精入卵的重要机制.受精后30 s, 受精塞和吸附的精子向精孔器外移动.受精后50 s, 受精塞和吸附的精子堵塞精孔器.受精后60 s, 受精塞吸附的精子开始解体,但是由于精孔管未封闭,还有精子通过精孔管进入到质膜.在人工受精过程中,卵子的单精受精屏障会因其周围精子密度大、精子与卵子距离短、精子运动速度快而被打破,从而导致这些卵子出现多精入卵的现象.受精后80 s, 精孔管仍然没有封闭,精孔器附近的精子明显出现活动能力的差异:精孔器外面的精子活动能力最强,精孔管旁边的精子活动能力较弱;精孔管外堆积的精子活性消失,受精塞吸附的精子已开始解体,经初步分析,这可能是进入其内的精子耗能有所差异的结果.受精后100 s,受精塞吸附的精子解体.     

唇鲳精子早期入卵观察

用扫描电镜对唇鳃成熟卵子及早期精子人卵过程进行观察。结果显示,唇鲋成熟卵子在动物极中央有一深凹陷的表面光滑的精孔器,其外径2．512μm,内径2．330μm,精子直径1．567μm。混匀的精卵刚遇水时,没有精子进入精孔器。受精后1s,精孔器内出现精子。受精后5S,组织切片显示,精子已经进入卵子内,并形成具有强烈抑制多精人卵作用的受精锥。受精后10S,精子在精孔器前庭集结,尚未形成受精塞。受精后20S,在精孔器内形成受精塞。受精塞没有阻塞精孔管,经分析它不是来源于皮层反应产物。受精塞形成后,可以吸附人卵的精子,这对多精入卵有积极的抑制作用;精子尾部在入卵过程中相互缠绕,这也是减少多精入卵的重要机制。受精后30s,受精塞和吸附的精子向精孔器外移动。受精后50S,受精塞和吸附的精子堵塞精孔器。受精后60s,受精塞吸附的精子开始解体,但是由于精孔管未封闭,还有精子通过精孔管进入到质膜。在人工受精过程中,卵子的单精受精屏障会因其周围精子密度大、精子与卵子距离短、精子运动速度快而被打破,从而导致这些卵子出现多精入卵的现象。受精后80s,精孔管仍然没有封闭,精孔器附近的精子明显出现活动能力的差异：精孔器外面的精子活动能力最强,精孔管旁边的精子活动能力较弱;精孔管外堆积的精子活性消失,受精塞吸附的精子已开始解体,经初步分析,这可能是进入其内的精子耗能有所差异的结果。受精后100S,受精塞吸附的精子解体。     

革胡子鲶受精过程的扫描电镜观察

应用扫描电镜观察和描述了革胡子鲶成熟卵和精子的形态、卵壳膜的表面结构和形态、受精孔的位置和结构、精子入卵过程的程序和变化。讨论了精子入卵过程及精孔细胞在解体之后可能转变为一种能够吸引精子在精孔区聚集的“受精素”物质等问题。     

金鱼精子入卵过程的扫描电镜观察

本文采用扫描电镜观察了金鱼(Carassius auratus)卵壳膜(chorion)表面结构和精子入卵过程。在壳膜的卵膜孔(micropyle)区有5—10条沟和嵴。位于精孔管下面,卵的质膜为一束较长的微绒毛组成的精子穿入部(sperm entry site)。授精5s,精子头的顶部已附着于精子穿入部,随即两者的质膜发生融合,而围于精子头部四周的微绒毛迅速伸长形成一受精锥,它不断将精子头部包裹。授精110s,精子的头部和颈部已完全进入卵内,受精锥本身也渐趋消失,但精子尾部仍平躺于卵的表面。皮层小泡是在授精30s后才开始破裂并释放其内含物,导致卵子表面呈蜂窝状,并在无膜内表面附着了大量球状物。     

尼罗罗非鱼[Tilapia nilotica （L）]卵子结构扫描电镜观察

本文对尼罗罗非鱼(亦称尼罗丽鲷)Ⅳ期末至Ⅴ期初的成熟卵子进行光镜与扫描电镜观察,发现其卵子的细胞核相,正处于第二次成熟裂中期。卵子皮质部的皮层颗粒小,排列不规则。 卵子质膜外有厚薄不同的两层膜,合为壳膜(chorion)。在卵子动物极的壳膜中央有一个卵膜孔(Micropyle)。受精后,可见精子从此孔迸入。这是精子入卵的唯一通道。受精时,壳膜上附有许多精子,但是由于精孔管径与精子头部横径大小相近,首先进入卵子的仅有一个精子。     

三疣梭子蟹精卵相互作用的扫描电镜观察

应用扫描电镜技术观察了三疣梭子蟹的精卵相互作用。未受精成熟卵表面较光滑、无受精孔,但有许多微孔。成熟卵外被卵膜,内为卵母细胞。在卵自然产出后,精子迅速发生顶体反应使顶体囊外翻并压入卵膜,而核仍留于卵膜外,核辐射臂不收缩且仍附着于卵膜上。三疣梭子蟹为多精着卵和多精入卵膜。精子外翻顶体囊压入卵膜后,核辐射臂陆续回缩直至消失。作用于顶体丝上的卵母细胞主动拖精作用对入卵膜精子的进一步入卵、受精至关重要,环状卵膜突起的向心伸展也有一定的协助作用。探讨了着卵精子的顶体反应、精子入卵膜的机制及卵子在精子入卵过程中的作用     

罗氏沼虾受精机制的细胞学研究

运用细胞学方法对罗氏沼虾的受精机理进行了初步研究,从卵巢中取邮的成熟卵,表面略有皱褶,无受精孔,不同于一般的节肢动物。成熟精子基部侧边分布许多成束的管状结构,其末端呈连续泡状。精卵接触时,这些泡破裂,膜与卵表膜融合,泡内的糖复合物对精卵识别,粘附可能起着重要和,从而使精子以基部侧边附着卵子表面,。     

长江中游鱼类的复殖吸虫Ⅰ.鲟拟动殖吸虫(动殖科)新属、新种的描述

从1981到1983年,作者等曾多次在湖北省宜都县和黄冈县团风镇两地,从事长江中游鱼类寄生吸虫的调查研究。在70多种鱼中,获得了一批吸虫标本,将陆续整理后发表。本文首先报告在中华鲟Acipenser sinensis Gray中发现的动殖科Zoogonidae Odhner,1911一新属、新种吸虫。       

Gamete interaction in the white sturgeon Acipenser transmontanus: a morphological and physiological review

Synopsis Sturgeon gametes differ from those of most fish in that the sperm possess acrosomes that undergo exocytosis and filament formation while the eggs possess numerous micropyles. Acipenser transmontanus eggs are encased by multilayered envelopes that consist of outer adhesive jelly coats and three structured layers interior to the jelly. The glycoprotein jelly layer only becomes adhesive upon exposure to freshwater. The layer interior to the jelly, layer 3, is the other carbohydrate-containing component of the egg envelope. This layer consists of a water-insoluble glycoprotein that, upon freshwater exposure, is hydrolyzed by a trypsinlike protease to yield a water-soluble, lower molecular weight carbohydrate-containing component. This component can be identified in the surrounding medium when unfertilized eggs are incubated in freshwater. This egg water component elicits acrosome reactions only in homologous sperm. The A. transmontanus sperm acrosome reaction is a Ca⁺⁺ and/or Mg⁺⁺ dependent event that includes the formation of a 10 μ long fertilization filament. A. transmontanus fertilization can occur at low sperm per egg ratios; however, crossfertilization of A. transmontanus eggs with lake sturgeon, A. fluvescens, sperm results in a very low number of fertilized eggs, even at high sperm per egg ratios. The morphological, physiological, and biochemical phenomenon reviewed in this paper are related to the environment in which they occur. Also, the possible role of the acrosome and the presence of numerous micropyles are discussed.     

湖鲟微卫星DNA引物应用于中华鲟亲子关系分析的初步研究

利用湖鲟(Acipenser fulvescens)的4对微卫星引物对中华鲟随机个体样本进行PCR扩增,分析电泳结果发现,4对引物均可在中华鲟个体中得到稳定的同源序列,其中2对引物所探测到的等位基因数目较多,在个体间表现出较高的多态性,利用它们产生的DNA指纹图谱,能够对1999年度获得的中华鲟亲鱼样本进行有效的个体区分。并且这两对湖鲟的微卫星引物在对1999年度已知亲本的同一家系中的中华鲟随机个体的分析中,表现为按照孟德尔方式进行共显性遗传。证明这2对微卫星引物可以用于鉴别中华鲟人工放流个体和自然繁殖个体。     

Surface ultrastructure of paddlefish eggs before and after fertilization

The surface ultrastructure of eggs of the paddlefish Polyodon spathula was investigated by scanning electron microscopy. Mature eggs of paddlefish possess four to 12 micropyles in the animal polar region. There are sperm entry sites in the egg surface under the micropyles which consist of tufts of microvilli. Five to nine sperm entry sites were observed on mature eggs. Probably, the number of sperm entry sites corresponds to the number of micropyles. In a few eggs, 1 min after fertilization the ball-like enlarged top of a cytoplasmic process (probably a full-grown fertilization cone) had reached the external aperture or the canal of several micropyles. In other micropyles of the same egg, a few smaller cytoplasmic processes or flocculent material were found in the micropylar canal. With one exception, no sperm tails were found there. The formation of the full-grown cytoplasmic process is possibly initiated before the cortical reaction has started in an area of the animal hemisphere. Three, 10 and 20 min after fertilization, the uneven surface of the cortical cytoplasm in the animal polar region rose gently where microvilli were much less than the in other area and together with a secondary polar body at the latter stage. Taken together, paddlefish eggs may have sperm entry sites corresponding to the number of micropyles and respond to the stimulus of fertilization by forming a few cytoplasmic processes–fertilization cones (larger and smaller). Sperm penetration into the egg may be achieved at an earlier stage of fertilization (sperm-egg contact), as inferred from the fact that a secondary polar body was formed at the 20-min stage irrespective of the exceptional finding of the sperm tail.     

长江葛洲坝枢纽坝下江段中华鲟成鱼性腺的观察

1981年1月,葛洲坝水利枢纽截流,中华鲟被大坝所阻而滞留在宜昌以下的江段。 1981年秋季在葛洲坝枢纽的坝下江段采集到中华鲟的Ⅲ、Ⅳ、Ⅵ期卵巢和Ⅲ、Ⅳ、Ⅴ期精巢,1982年秋季又采集到中华鲟产出的卵和早期鱼苗。研究结果表明,中华鲟在坝下江段不仅能发育成熟,而且能自然产卵。为了保护和增殖中华鲟,人工繁殖放流的方法是切实可行的。同时,必须严禁滥捕,以保护中华鲟资源。       

Fine Structure of the Envelope and Micropyles in the Eggs of the White Sturgeon, Acipenser transmontanus Richardson

The structure of the egg envelope and micropyles of the white sturgeon was examined with light and electron microscopy. The mature ovum is 3.5–4.0 mm in diameter and is covered by a thick envelope (50 μm) that consists of four distinct layers. The outermost layer, L4, is electron dense and amorphous. Interior to this is layer three (L3), containing numerous pores, or ductules. Layer two (L2) contains screwlike projections that anchor L3 and L4 to the egg. The innermost layer, L1, is closely apposed to the oolemma. Numerous micropyles (average 7) are restricted to a 100–200 μm region at the animal pole and penetrate the egg envelope. The outer opening of these rnicropyles measures 15 μm in diameter. The micropylar canal tapers twice, eventually terminating at the oolemma with an inner opening diameter of 1.2 μm. The micropyles of the white sturgeon egg appear more complex than micropyles in other fish eggs.     

Formation and structure of egg envelopes in Russian sturgeon Acipenser gueldenstaedtii (Acipenseriformes: Acipenseridae)

The covering of the eggs in Russian sturgeon Acipenser gueldenstaedtii consists of three envelopes (the vitelline envelope, chorion and extrachorion) and is equipped with multiple micropyles. The most proximal to the oocyte is the vitelline envelope that consists of four layers of filamentous and trabecular material. The structural components of this envelope are synthesized by the oocyte (primary envelope). The chorion encloses the vitelline envelope. The extrachorion covers the external surface of the egg. Examination of the arrangement of layers that comprise the egg envelopes together with the ultrastructure of follicular cells revealed that the chorion and extrachorion are secondary envelopes. They are secreted by follicular cells and are built of homogeneous material. During formation of egg envelopes, the follicular cells gradually diversify into three morphologically different populations: 1) cells covering the animal oocyte region (cuboid), (2) main body cells (cylindrical) and (3) micropylar cells. The apical surfaces of follicular cells from the first two populations form processes that remain connected with the oocyte plasma membrane by means of gap junctions. Micropylar cells are located at the animal region of the oocyte. Their apical parts bear projections that form a barrier to the deposition of materials for egg envelopes, resulting in the formation of the micropylar canal.     

中华绒螯蟹成熟卵形态和超微结构的研究

中华绒螯蟹的成熟卵仅有初级卵膜，无次级和三级卵巢，质膜初期厚而多层，且具皱褶，卵核在卵的发育过程中变化很大，未发见中心粒，内质网和高尔基体均始见于蟹卵发育的初期，皮层颗粒先出现于蟹卵深部，随后移到卵的表层，无滋养细胞，蟹卵由卵泡细胞提供物质，形成卵黄，此外，还可直接从血淋巴内摄取卵黄前身物质。