怀头鲇成熟卵膜表面扫描电镜观察

The surface ultrastructure of mature egg chorion of the tamed northern sheatfish Silurus soldatovi in Hei- longjiang river was investigated by scanning electron microscopy. The outermost layer was composed of a thin lamella of a jelly coat. The surface of ielly coat was characterized by overlapping net-like fibrillar lamellae, many clefts with bridges and pores. The pore canals were 0.25 μm in diameter. The pore density was about 0.7 - 1.0/μm^-2. The pores on the surface of jelly coart were distributed uniformly. Mature eggs of sheatfish possessed a funnel-shaped micropyle in the animal polar region. The micropylar region was about 0.04 mm^2 area in diameter with 3 - 8 ridges in radial arrangement. Fertilized eggs in which jelly coats were removed mechanically presented no adhesiveness and exhibited inlays of irregular granules on their surface [Acta Zoologica Sinica 51 （5）： 940-946, 2005].     

犬首鮈卵子发生过程及成熟卵膜形态结构观察

摘要：通过组织切片和扫描电镜技术对犬首鮈卵子发生过程及成熟卵膜表面结构进行观察。结果显示,犬首鮈卵子发生过程可以分为Ⅰ-Ⅵ时相:第Ⅰ时相卵母细胞主要有卵原细胞构成;第Ⅱ时相卵母细胞外层出现滤泡细胞;皮质液泡和卵黄颗粒分别发生在第Ⅲ、Ⅳ时相;第Ⅴ时相卵母细胞为成熟的卵子,富含丰富的卵黄和少量皮质液泡;第Ⅵ时相卵母细胞退化进而被卵巢吸收。卵膜孔呈漏斗状,卵孔区域类型属于降旋混合系统。犬首鮈成熟卵膜表层具有特殊的柱状体结构,高度为18.3~30.6um,平均分布密度为0.15个/um2,分析可能为该物种或生态类型的卵膜结构特征,推测对产沉粘性卵鱼类受精卵孵化、胚胎发育起重要作用。     

温度变化中国林蛙胚胎发育的影响

开展中国林蛙南移和人工养殖是一项很有意义的工作,而南方多变的气温是否影响其胚胎发育是一个尚未研究的课题。本文利用受精卵在不同温度的恒温培养箱间移换,研究了温度变化对中国林蛙早期胚胎发育的影响,结果表明：（１）快速升温对中国林蛙胚胎卵化率,正常率均有影响,且温差越大影响越大;缓慢升温对胚胎的影响与温差大小和升温起点有关,高起点升温对胚胎的影响比低起点的升温更大,生产中快速升温以不超大２℃,慢速升温以     

雌核发育兰州鲇胚胎发育和形态特征的研究

该研究通过紫外线(UV)灭活的黄颡鱼(Pelteobagrus fulvidraco)精子利用冷休克方法诱导兰州鲇(Silurus lanzhouensis)雌核发育二倍体(G2n)、单倍体(N)、杂交二倍体(H2n),以及同源精子诱导的普通二倍体(2N)的胚胎发育时序和发育生物学特征进行了观察比较.结果 显示,(1)...     

温度对斑马鱼胚胎发育的影响

目的探讨温度对斑马鱼胚胎发育速度及器官分化的影响。方法将带绿色荧光的转基因斑马鱼胚胎分配至3个培养皿中,各放160个胚胎,分别放置于28.5℃(标准发育温度)、31℃(高温)和25℃(低温)3个不同温度中进行孵育,孵育至3 h、6 h、10 h、24 h和48 h时进行观察拍照,并在36 h、48 h和72 h时用荧光显微镜观察胚胎的心脏和血管,比较不同温度对胚胎发育进程及各器官发育的影响。结果 3种温度下,胚胎存活率分别为92.5%、89.4%和91.25%,没有显著性差异。相同发育时间内,与标准温度中发育的胚胎相比,31℃中的胚胎发育较快,而25℃的胚胎发育所处的时期较早。发育到相同分期,31℃所需时间比标准温度短,而25℃所需时间长。3个不同温度下,胚胎心脏和血管的发育均不受影响。结论高温促进胚胎发育,低温延迟发育,但高温或低温均不影响胚胎器官正常发育。结合实际科研需要,可通过调控温度来调节斑马鱼胚胎的发育进程。     

香鱼成熟卵母细胞过熟进程中卵膜结构变化的扫描电镜观察

{{@ convertAbstractHtml(article.abstractinfoCn, \"cn\")}}       

抗肿瘤药物对小鼠早期胚胎发育的影响

表观遗传修饰在基因表达和克隆胚胎的早期发育方面有重要作用.表现遗传修饰至少发生在两个关键时期--配子形成期和植入前胚胎,如果在此期间发生异常,则会导致胚胎的死亡及出生后各种疾病的发生.其中DNA的甲基化是最重要的一种表观遗传修饰类型,DNA甲基化在哺乳动物发育过程中起关键作用.综述几种类型抗肿瘤药物作用机制——其使胚胎的DNA甲基化降低,引起转录活性降低,进而导致胚胎发育停滞.     

遗传背景对小鼠四倍体胚胎发育的影响

不同遗传背景的小鼠2-细胞期胚胎经过电融合后,胚胎的融合效率和四倍体胚胎的发育能力存在着一定的差异。本试验采用C57(C57×C57)、ICR(ICR×ICR)、BALB/c(BALB/c×BALB/c)、B6D2F2(B6D2F1×B6D2F1)、B6C3D2F2(B6C3F1×B6D2F1)品系的二倍体2-细胞期胚胎在相同的条件下经过电融合处理,结果表明:小鼠四倍体胚胎的获得效率受小鼠遗传背景的影响,远交系小鼠胚胎B6D2F2和B6C3D2F2的融合率显著高于近交系C57,ICR和BALB/c(P<0.05);四倍体胚胎在体外的发育情况也受其遗传背景的影响,在桑椹胚发育率和囊胚发育率上B6D2F2和B6C3D2F2品系的四倍体胚胎都显著高于C57和BALB/c品系的四倍体胚胎(P<0.05);杂合和纯系遗传背景的小鼠四倍体胚胎囊胚细胞数目相比具有显著差异(P<0.05或P<0.01);不同遗传背景的小鼠四倍体胚胎着床率间不存在显著差异(P>0.05);杂合背景的小鼠四倍体胚胎得到5只发育至13.5dpc(dayspostcoitum,dpc)的胎儿,纯合背景的小鼠四倍体胚胎得到0只发育至11dpc的胎儿。     

四种重金属对中国鲎(Tachypleus tridentatus)胚胎发育的影响

分析了不同离子浓度的Zn、Pb、Cu、Cd对中国鲎胚胎发育的影响.结果表明①4种金属离子浓度≤渔业水域水质标准浓度4倍时,对中国鲎胚胎发育无明显毒性效应;≥渔业水域水质标准浓度8倍时,Cd离子和Cu离子对中国鲎胚胎发育无明显影响,而Zn离子组Pb离子组胚体发育随离子浓度提高而卵径变小,发育速度下降;②浓度为1.6mg/L时,Zn和Pb离子组胚胎致畸率分别为44%和58%,Pb离子组胚体孵化率仅2.67%;③4种重金属对中国鲎胚胎发育的毒性效应表现为Pb＞Zn＞Cu=Cd;④中国鲎胚胎对重金属有蓄积作用,蓄积效应随金属种类不同而异.     

黏性卵鱼类受精卵一种快速高效的显微注射方法

黏性卵鱼类受精卵遇水后产生的黏性和卵壳变硬的现象严重影响着大批量显微注射操作的速度和随后的取材。研究建立了一种高效的黏性受精卵快速脱黏显微注射方法, 并利用荧光标记葡聚糖Alex-Fluor488-dextran评估了消化脱黏、直接注射和脱壳注射三种方法的技术特点和适用范围。结果表明: 在23℃, 用0.25%胰蛋白酶(pH=7.1-7.4)消化4min可获得脱黏受精卵。与直接注射和脱壳注射方法相比, 研究建立的消化脱黏方法兼具二者的优点: 在受精后5min可以开始显微操作, 无黏性, 容易进针, 胚盘清晰便于观察、注射后容易培养和取材。实验方法适用于研究与黏性卵鱼类卵子发生、卵-胚转换和早期胚胎发育密切相关基因的功能, 亦可满足追踪受精过程中核质细微变化研究的需要。     

池沼公鱼移殖放流试验研究

作者于1984—1986年进行了池沼公鱼移殖放流试验研究,移入水库的池沼公鱼已能自然产卵繁殖,形成了经济群体。本文论及了移殖放流的理论依据、移殖放流技术、移殖放流效果、移殖池沼公鱼的生态效益的分析和池沼公鱼的资源管理。     

Fertilization of newt coelomic eggs in the absence of jelly envelope material

Summary Fertilization ofCynops pyrrhogaster (Japanese newt) coelomic eggs was studied in the absence of jelly envelope material or synthetic high polymer. An undiluted sperm fluid from the vas deferens fertilized coelomic eggs in the absence of the jelly envelope material or synthetic high polymer. The fertilized eggs developed beyond gastrulae and formed tail bud embryos. These results indicate that the fertilization process does not depend upon the presence of jelly envelope material or synthetic high polymer and that the sperms within the vas deferens are already capable of fertilizing the eggs inC. pyrrhogaster. The sperm suspension in Holtfreter's balanced salt solution (H-sperm) fertilized the coelomic eggs without the jelly envelope material or synthetic high polymer. These eggs had been suspended in Holtfreter's balanced salt solution (H) or in 1/20 strength H (1/20 H) prior to insemination (H-eggs or 1/20 H-eggs). In contrast, the sperm suspension in 1/20 H (1/20 H-sperm) did not fertilize 1/20 H-eggs, but dit H-eggs. In the latter case, H surrounding the eggs may affect sperms, allowing them to be fertilized. The 1/20 H-sperms regained their ability to fertilize 1/20 H-eggs on re-exposure to H. The 1/20 H-sperm also fertilized jelly eggs. The results of the dejellied egg experiment showed the same pattern. These results indicate that the sperms within the vas deferens lose their capacity to fertilize 1/20 H-eggs on exposure to low ionic strength solution (1/20 H); this capacity is restored by exposure to high ionic strength solution (H) or to jelly envelope.     

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     

泥鳅精子入卵的动力作用

在扫描电镜下,泥鳅成熟卵卵膜孔外围呈现完整的左涡旋状结构,受精时精子是顺着涡旋的流线进入卵膜孔。涡旋纹理接近对数螺线。本文分析了真骨鱼类的受精因素,除已知的化学因素外,还存在物理因素。也讨论了泥鳅成熟卵卵膜孔形态形成的必然性。     

Identifying MicroRNA and mRNA Expression Profiles in Embryonic Stem Cells Derived from Parthenogenetic, Androgenetic and Fertilized Blastocysts

MicroRNAs (miRNAs) are a class of highly conserved small non-coding RNA molecules that play a pivotal role in several cellular functions. In this study, miRNA and messenger RNA (mRNA) profiles were examined by Illumina microarray in mouse embryonic stem cells (ESCs) derived from parthenogenetic, androgenetic, and fertilized blastocysts. The global analysis of miRNA-mRNA target pairs provided insight into the role of miRNAs in gene expression. Results showed that a total of 125 miRNAs and 2394 mRNAs were differentially expressed between androgenetic ESCs (aESCs) and fertilized ESCs (fESCs), a total of 42 miRNAs and 87 mRNAs were differentially expressed between parthenogenetic ESCs (pESCs) and fESCs, and a total of 99 miRNAs and 1788 mRNAs were differentially expressed between aESCs and pESCs. In addition, a total of 575, 5 and 376 miRNA-mRNA target pairs were observed in aESCs vs. fESCs, pESCs vs. fESCs, and aESCs vs. pESCs, respectively. Furthermore, 15 known imprinted genes and 16 putative uniparentally expressed miRNAs with high expression levels were confirmed by both microarray and real-time RT-PCR. Finally, transfection of miRNA inhibitors was performed to validate the regulatory relationship between putative maternally expressed miRNAs and target mRNAs. Inhibition of miR-880 increased the expression of Peg3, Dyrk1b, and Prrg2 mRNA, inhibition of miR-363 increased the expression of Nfat5 and Soat1 mRNA, and inhibition of miR-883b-5p increased Nfat5, Tacstd2, and Ppapdc1 mRNA. These results warrant a functional study to fully understand the underlying regulation of genomic imprinting in early embryo development.     

Closure of the micropyle during embryonic development of some pelagic fish eggs

The fine structure of the egg envelope and micropyle was studied in unfertilized and developing eggs of the flounder Paralichthys olivaceus (Temminck & Schlegel), the Alaska pollack Theragra chalcogramma (Pallas), the Japanese tilefish Branchiostegus japonicus (Houttuyn) and the porgy Pagrus major (Temminck & Schlegel). The outer envelope surface of the unfertilized egg was wrinkled, while the inner surface was folded. The micropyle of the unfertilized egg consisted of a shallow vestibule and a distinct canal. The micropylar region of the inner surface of the envelope had a conical- or bowl-shaped protrusion. In developing eggs, the thickness of the envelope decreased and showed smooth outer and inner surfaces which indicated that it had been stretched tangentially at the time of the perivitelline space formation. The lumen of the micropylar canal was invariably occupied with envelope material. We postulate that the blockage of the micropylar canal is a result of the stretching of the envelope. The closure of the micropyle inhibits sperm and external pathogens from penetrating into the perivitelline space and seems to be involved in both the permanent prevention of polyspermy and the protection of the developing embryo from bacterial infection.