胚胎发育

In addition, using RT-PCR to detect expression of centrin homogene during Urechis unicinctus spermatid deferentiation and early embryonic development. The result revealed that (1) expression of HsCEN1 homogene is present during spermatid defferentiation including spermtid and sperm, but not in adult tissues including body wall tissue,intestinal mucous memberane cells and cell in coelom succus;(2) expression of HsCEN1 homogene is not present in unfertilized oocytes but present in that of released polar bodies after fertilization and parthenogenesis oocytes treated with A23187;(3) expression of HsCEN1 homogene is present during early embryonic development including two-cell stage,multicell stage,gastrula to trochophora.

我们还用RT-PCR方法检测了Centrin同源基因在单环刺螠精子分化过程和早期胚胎发育过程的表达，结果显示：在单环刺螠精子发生过程中的精细胞、精子团、精子中都有表达，而在成体的体壁组织、消化道组织、体腔球中则没有表达；在未受精卵中没有表达，而在受精后释放极体的受精卵和经A23187孤雌激活的卵中则有表达；在单环刺螠的早期发育过程——二细胞胚胎、多细胞胚胎、原肠胚、早期担轮幼虫——中都有表达。

It is not easily to gain poultry unicell fertilized egg and earlier embryo for the peculiarities of embryonic development.

家禽的胚胎发育与哺乳动物有着很大的不同，由于胚胎发育的特殊性，使得家禽不易获得单细胞受精卵和早期胚胎。

In different embryo developmental stages, its expression was decline gradually . This result indicated that the survivin may play important role in oogenesis and early embryogenesis. One PABP gene was cloned from the subtractive cDNA library.

RT-PCR分析表明该基因主要在卵巢中表达，随着胚胎发育表达逐渐减少，这可能表明该基因在半滑舌鳎卵子形成和早期胚胎发育中起到重要作用。ePABP是特异的在卵巢和早期胚胎表达的Poly结合蛋白。

The early embryonic development of Rana rugulosa was studied at water temperature of 18～23℃.The course, from its fertilized egg stage to operculum completely closed stage, may be divided into 25 stages,which totally take about 126 hours.

无尾两栖类的胚胎发育在胚胎学、发育生物学等学科的研究中有着重要意义，因而有关的研究国内外均有报导，Shumway（1940）详细研究了豹蛙的发育，并提出了较系统的发育资料［1］，故而被国内外许多教材加以采用。

The whole embryonic developmental course results from the ordinal expression of a large number of genes according time and space. Many developmental mechanisms have been determined in the embryonic stage. Therefore, study on the regulative mechanism of embryonic development is important for elucidate principles of biologic growth, development and evolution.

整个发育过程都是大量的基因按照一定的时间、空间和次序表达的结果，其中许多调控机制在胚胎发育阶段就已经决定，因此，研究胚胎发育调控机制对于阐明生物的生长、发育和起源进化具有重要意义。

BACKGROUND: Compared with adult mesenchymal stem cells, yolk sac-derived MSCs of early embryo have stronger self-renewal capacity and plasticity. Moreover, they could differentiate into angioblast and hemopoietic stem cells during embryonic development and trigger embryonic angiogenesis and hemopoietic tissue development.

背景：与成体间充质干细胞相比，来源于早期胚胎的卵黄囊间充质干细胞有更强的自我更新能力和可塑性，且在胚胎发育过程中可分化为成血管细胞和造血干细胞，启动胚胎血管发生和造血组织发育。

The variation to vitellin polypeptide was studied by SDS-PAGE during embryogenic and postembryonic development to Chrysopa septempunctata. The results indicated that vitellin was degradated constantly during embryonic development, and the bands of vitellin couldn't be detected in the 4th day of ovum development.

用SDS-PAGE研究了大草蛉胚胎发育和胚后发育过程中卵黄蛋白多肽的变化动态，结果表明，卵黄蛋白在胚胎发育过程中被不断降解，在卵发育的第4天已经基本上看不到卵黄蛋白的条带。

In conclusion, either electrofusion parameter or developmental stage of donor embryos have a significant effect on the efficiency of NT, NT embryos require different concentration of serum at their different development stages.

结果表明，电融合参数和供体胚胎的发育阶段以及受体卵母细胞的状态对NT效果有显著影响，在NT胚胎的不同发育阶段采用不同的血清种类和浓度可提高其胚胎发育能力。

We suppose that there is a presently undefined subfraction of stem cell population that exists in a number of tissues beyond embryonic development. We term them postembryonic pluripotent stem cells. They differ from embryonic stem cells in that they gradually lose some differentiation potentials during development and adopt some special phenotypes once within a certain tissue. They can give rise to different kinds of stem cells; therefore, help to maintain balance during development and metabolism. They provide cells not only for the damaged tissues they reside, but also for damaged tissues different from them by migration triggered by proinflammatory cytokines or growth factors.

我们认为在胚胎发育后的多种组织中都存在一类原始干细胞群体，它们和造血干细胞、神经干细胞等多能干细胞不同，后者只能分化为特定胚层的细胞，而这类原始干细胞可分化为不同胚层的组织细胞；另一方面，它们区别于胚胎干细胞，在妊娠期间会逐渐失去部分分化潜能，并且会出现一些特殊表型或者分子标志，我们称其为胚胎后亚全能干细胞，这类干细胞具有下列特性：可分化为不同胚层的细胞，分布于身体的所有组织和器官，具有相同的表型或标志；他们在胚胎期存在于一些或全部的组织和器官中，可分化为不同类型的多能干细胞并在生长发育和新陈代谢中维持这些多能干细胞保持平衡；可以参与机体自我修复和更新，不仅能分化为所在器官的组织特异性细胞，参与器官重塑，也可以在炎症因子或者生长因子的趋化作用下，远处转移修复受损组织。

This paper was mainly working on the biochemical changes (water, carbohydrate, lipid, fatty acid, protein, amino acid) during embryonic development of Cherax quadricarinatus. At the same time, we especially worked on the yolk protein-vitellin in two aspects: 1. Isolation, purification and characterization of vitellin from the ovary of female Cherax quadricarinatus.

本文对红螯螯虾胚胎发育过程中的主要生化物质(水分、碳水化合物、脂类、脂肪酸、蛋白质、氨基酸)进行了测定，特别是对胚胎发育过程中主要的营养物质——卵黄磷蛋白的结构和含量变化做了细致的研究，同时讨论了这些物质的变化与红螯螯虾胚胎发育形态发生的相关性。

As she looked at Warrington's manly face, and dark, melancholy eyes, she had settled in her mind that he must have been the victim of an unhappy attachment.

每逢看到沃林顿那刚毅的脸，那乌黑、忧郁的眼睛，她便会相信，他一定作过不幸的爱情的受害者。

Maybe they'll disappear into a pothole.

也许他们将在壶穴里消失