内中胚层

The rearrangement of the blastula into a three-dimensional organism with inner middle and outer layers occurs during gastrulation.

在原肠胚形成过程中，囊胚重新排列，形成包括内层，中层，外层的三围组织。

Tetraploid embryos could be produced by electrofusion at the stage of two-cell embryos, which could develop to blastocysts followed by fusion of cytoplasm and nucleus and cleavage in vitro. During the fusion of cytoplasm, the DNA methylation levels of the fused embryos are as high as these of two-cell diploid embryos in vivo Then the embryos are rapidly demethylated when the nucleus begin to fuse, resulting in the lowest DNA methylation levels when the nucleus are fused completely. After that, the DNA methylation levels of the fused embryos are gradually increased until the morula stage. However, whereas an asymmetric distribution of DNA methylation is established in vivo-derived blastocysts with a higher methylation level in the inner cell mass than that in the trophectoderm, we can not detect the asymmetric distribution in most in vitro-derived tetraploid blastocysts.

结果表明：利用电融合方法制备的小鼠四倍体胚胎在体外培养体系中经历细胞质融合、细胞核融合及细胞继续分裂发育直到囊胚期的过程，在细胞质融合的时候胚胎卵裂球同体内体外培养二倍体胚胎一样，呈现高度甲基化状态；在细胞核开始融合的时候，甲基化水平急速下降，在细胞核完全融合的时候甲基化水平达到最低点；随着胚胎继续分裂，胚胎甲基化水平逐渐增加，在桑葚胚期甲基化水平最高；但是囊胚期四倍体胚胎内细胞团同滋养层细胞甲基化荧光信号没有差别，这与体内体外培养二倍体囊胚内细胞团细胞甲基化荧光强度高于滋养层细胞甲基化荧光强度不同。

Tetraploid embryos could be produced by electrofusion at the stage of two-cell embryos, which could develop to blastocysts followed by fusion of cyto-plasm and nucleus and cleavage in vitro. During the fusion of cytoplasm, the DNA methylation levels of the fused embryos are as high as these of two-cell diploid embryos in vivo Then the embryos are rapidly demethylated when the nucleus begin to fuse, resulting in the lowest DNA methylation levels when the nucleus are fused completely. After that, the DNA methy-lation levels of the fused embryos are gradually increased until the morula stage. However, whereas an asymmetric distribu-tion of DNA methylation is established in vivo-derived blastocysts with a higher methylation level in the inner cell mass than that in the trophectoderm, we can not detect the asymmetric distribution in most in vitro-derived tetraploid blastocysts.

结果表明：利用电融合方法制备的小鼠四倍体胚胎在体外培养体系中经历细胞质融合、细胞核融合及细胞继续分裂发育直到囊胚期的过程，在细胞质融合的时候胚胎卵裂球同体内体外培养二倍体胚胎一样，呈现高度甲基化状态；在细胞核开始融合的时候，甲基化水平急速下降，在细胞核完全融合的时候甲基化水平达到最低点；随着胚胎继续分裂，胚胎甲基化水平逐渐增加，在桑葚胚期甲基化水平最高；但是囊胚期四倍体胚胎内细胞团同滋养层细胞甲基化荧光信号没有差别，这与体内体外培养二倍体囊胚内细胞团细胞甲基化荧光强度高于滋养层细胞甲基化荧光强度不同。

Tetraploid embryos could be produced by electrofusion at the stage of two-cell embryos, which could develop to blastcysts fellowed by fusion of cytoplasm and nucleus and cleavage in vitro.After fusion of cytoplasm, the DNA methylation levels of the fused embryos was very high as well as two-cell diploid embryos in vivo.Then the embryos was rapiddly demethylated when the nucleus begin to fuse, resulting the lowest DNA methylation levels when the nucleus fused completely.After that, the DNA methylation levels of fused embryos were gradually increased until the blastocysts stage.However, whereas an asymmetric distribution of DNA methylation was established in an vivo-derived blastocysts with a higher methylation level in the inner cell mass than in the trophectoderm, in most vitro-derived tetraploid blastocysts, we can not detect the asymmetric distribution.

结果表明：利用电融合方法制备的小鼠四倍体胚胎在体外培养体系中经历细胞质融合、细胞核融合及细胞继续分裂发育直到囊胚期的过程，在细胞质融合的时候胚胎卵裂球同体内体外培养二倍体胚胎一样，呈现高度甲基化状态；在细胞核开始融合的时候，甲基化水平急速下降，在细胞核完全融合的时候甲基化水平达到最低点；随着胚胎继续分裂，胚胎甲基化水平逐渐增加，在囊胚期甲基化水平最高；但是囊胚期四倍体胚胎内细胞团同滋养层细胞甲基化荧光信号没有差别，这与体内体外培养二倍体囊胚内细胞团细胞甲基化荧光强度高于滋养层细胞甲基化荧光强度不同。

Germ potential is established after conception in a totipotent zygote and retained subsequently during development in blastomers of morula , cells form the inner cell mass of blastocyst , epiblast and population of primordial germ cells .

种子潜能的确定是全能的受精卵形成之后，并且随后在桑葚胚，胚泡内层细胞，外胚层和原生殖细胞的发育过程中保留。

Seeds remaining attached in dehisced fruit; seed coat with thick inner layer of dense black sclerenchyma and spongy outer layer bounded externally by a shiny black pellicle; endosperm copious; embryo straight or slightly curved; cotyledons elliptic, flattened; hypocotyl superior.

种子附存于开裂的果中；种皮具厚的内层深黑色厚壁组织和海绵状的外层，其外部边界具发亮的黑色表膜。胚乳丰富；胚直或稍弯曲；子叶椭圆形，扁平；下胚轴上位。

Compared with other signals, TGFβ/Nodal plays a key role in the induction of mesendoderm.

相比于其他信号通路，Nodal信号通路对于胚胎的中内胚层的诱导起到关键的作用。

From E12. 5 onwards, partially distinct patterns of expression of these genes are observed in the neuroepithelium, sense organs and endodermal-derived organs.

从E12.5起，这些基因显示出部分表达差异，尤其在神经上皮，感觉器官和内胚层衍生的器官中。

The galactosyl oligosaccharides of raffinose series are widely distributed in seeds of many species and are localized in tissues that remain viable after desiccation, including the embryo and aleurone layer of cereals, cotyledons and axis tissues of legumes and other dicots.

棉子糖半乳糖苷系列寡糖广泛分布在许多种植物种子中，并存在于干燥后仍能保持活力的组织内，如禾谷类种子的胚及糊粉层，豆类及其他双子叶植物的子叶和胚轴组织等。棉子糖半乳糖苷系列寡糖在禾谷类种子的非自溶性中央胚乳中不合成，但存在于蓖麻种子的自溶性胚乳细胞中。

In this study, in utero transfection plasmid DNA method was set up to embryonic mouse. The GFP expression vector pCAGGS-IRES-EGFP was microinjected into the lateral cerebral ventricle of E 14.5d mouse embryos through the uterine wall. Then, the 30 V square-wave pulse was delivered across the head for 5 times and interval 50m sec by electrodes in parallel with the median raphes.

本研究旨在通过子宫内电穿孔法，建立鼠胚大脑皮层体内基因转移体系：将带有绿色荧光蛋白的表达载体pCAGGS-IRES-EGFP显微注入胚胎期14.5 d的鼠胚侧脑室中，电极沿与脑中缝平行的方向夹持鼠脑，在电压30 V，脉冲时间50 ms，脉冲数5的条件下方波电击，将外源基因转移到室管膜层细胞。

It has been put forward that there exists single Ball point and double Ball points on the symmetrical connecting-rod curves of equilateral mechanisms.

从鲍尔点的形成原理出发，分析对称连杆曲线上鲍尔点的产生条件，提出等边机构的对称连杆曲线上有单鲍尔点和双鲍尔点。

The factory affiliated to the Group primarily manufactures multiple-purpose pincers, baking kits, knives, scissors, kitchenware, gardening tools and beauty care kits as well as other hardware tools, the annual production value of which reaches US$ 30 million dollars.

集团所属工厂主要生产多用钳、烤具、刀具、剪刀、厨具、花园工具、美容套等五金产品，年生产总值3000万美元，产品价廉物美、选料上乘、质量保证，深受国内外客户的青睐