后原肠胚

The outer layer of a blastula that gives rise to the ectoderm after gastrulation.

外胚层囊胚的外层，在原肠胚形成之后生后外胚层组织

The formation of a gastrula from a blastula by invagination.

外胚层囊胚的外层，在原肠胚形成之后生后外胚层组织

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。

This suggests that CaHIRA plays a role in the early embryo development and the late stages. The different expression characters of hira gene in these fish species may be related to the different reproduction models. The research on Drosophila has indicated hira gene related to sperm nucleus decondensation during fertilization. The high expression of hira gene before fertilization is prepared for the sperm nucleus decondensation and the formation of male prenucleus because colored crucian carp is bisexual reproduction. However, the sperm nucleus is not decondensated during the fertilization and is only to activate egg nucleus in gynogenetic gibel carp.

在彩鲫中，从未受精卵到胚胎发育的各个时期均可检测到表达，但表达量发生明显变化，受精后表达量迅速下降，直到原肠胚期表达量有所上升，并一直保持到出苗。hira基因在两亲缘种成熟卵子受精前后表达情况不同，可能与两种鱼不同的生殖方式有关。

The infolding of a portion of the outer layer of a blastula in the formation of a gastrula.

外胚层囊胚的外层，在原肠胚形成之后生后外胚层组织

It showed that in conditions of water temperature 20～21℃,salinity 20～30,pH 8.0～8.3,the fertilized eggs developed to 2-cell in about 2h,blastula stage in about 15h,gastrula stage 30h and the hatched out larva 152h after fertilization.

其结果表明：在水温20-21℃、盐度20-30、pH值8.0-8.3的条件下，受精卵受精后2h为2细胞期、15h为囊胚期、30h为原肠期、55h为胚体期、152h孵出仔鱼

" During the second week following fertilization, gastrulation (cell differentiation and migration ) results in the formation of three tissue types."

受精之后第二周，原肠胚形成后，胚胎分化为三个组织类型

This one mode pays close attention to network credence foundation of the businessman very much.

这一模式非常关注商人的网络信用基础。

Cell morphology of bacterial ghost of Pasteurella multocida was observed by scanning electron microscopy and inactivation ratio was estimated by CFU analysi.

扫描电镜观察多杀性巴氏杆菌细菌幽灵和菌落形成单位评价遗传灭活率。