同胚的

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。

In order to investigate cellular and molecular interactions between symbionts and their host endoderm cells, an homogeneous population of endoderm cell is required.

为了研究共体与宿主內胚层细胞之间分子与细胞的交互作用，必须要有一群同质性的內胚层细胞。

In the first part, the concepts of the completely normal spaces and strong completely normal spaces in L-topological spaces are defined, which are the generalization of the completely normal spaces in general topological spaces. They are some good properties such as hereditary, weakly homeomorphism invariant properties, good L-extension, but they arent producible in general.

第一部分的主要内容如下：第一部分这一部分是将一般拓扑学的完全正规分离性的概念推广到了L-拓扑空间，给出了L-拓扑空间的完全正规分离性和强完全正规分离性的定义并讨论了它们的若干性质，比如，它们都是可遗传的，弱同胚不变的，"Lowen意义下好的推广"等。

Stamens 1 or 2 × as many as sepals; filaments short, slender; anthers basifixed, mostly oblong or linear, 4-loculed, dehiscing by slits, antisepalous anthers sometimes somewhat longer than antipetalous ones; pollen grains shedding at 3-celled stage. Ovary inferior, 1(or 2)- or 4-celled, septa solid or practically absent (present only at base and apex of ovary); styles as many as sepals, alternisepalous, free, mostly short, grading into globose or subulate stigmas, spreading in fruit; stigmatic papillae hairlike; ovules as many as styles, rarely 1, apical, pendulous, anatropous.

雄蕊1或2 *同数萼片；花丝短，纤细；花药基着，通常长圆形或者线形，4室，纵向开裂，对萼花药稍比对瓣花药长；花粉粒在3室的阶段散落子房下位，1(或者2)或4室，隔膜实心或几乎无(只在基部和子房先端存在)；花柱和萼片同数，与萼片互生，离生，柱头乳突毛发状；胚珠与花柱同数，很少1，顶生，倒生。

Ovary superior, disk absent, locules and carpels 3-5 or more; placentation axile; ovules anatropous with a single integument, 10 or more per locule; styles as many as carpels, distinct or connate, generally persistent.

子房上位，无花盘，室和心皮3-5或更多；中轴胎座胚珠倒生，有单个珠被，每子房室有10个或更多的胚珠；花柱和心皮同数，离生或者合生，通常宿存。

The researchs on isozymes indicated that some varieties of isozyme loci present during the embryo development. There are 7 esterase loci and 5 acid phosphatase loci during the periods between nucellar filament and early globular embryo; both of Est and Acp appeared the most diversity in the stage of 8-nucleate embryo sac.

用聚丙烯酰胺凝胶电泳的方法研究鹤顶兰从指状突起出现到早期球形胚形成的全过程中酯酶、酸性磷酸酶的变化发现：这一过程中酯酶表达有7个同工酶位点，酸性磷酸酶有5个同工酶位点，两者均在八核胚囊时期变化最显著。

Embryoids occurred in all stages as zygotic embryo and were asynchronous. embryoids were white and opague.

体胚分化经历与合子胚相似的发育过程，有球形期、心形期、鱼雷期和子叶期，体胚发生是不同步的，在同一块愈伤组织上有处于不同发育阶段的体胚。

In addition, isozymes changes of SOD and POD were observed in groups treated with laser after seeds being soaked for 24 h and when embryonic buds emerged, while no change was observed in the group treated at the one-leaf stage.

SOD、POD同工酶的酶谱在浸种24小时和胚芽露头期经激光处理后改变，在一叶期处理后没有改变；CAT同工酶谱没有变化；在一叶期处理的三种同工酶谱都没有改变。

I am accused of being overreligious," she said in her quiet, frank manner,"but that does not prevent me thinking the children very cruel who obstinately commit such suicide.""

客人们在卡罗利娜·埃凯家里，举止就文雅一些，因为卡罗利娜的母亲治家很严厉。

Designed by French fashion house Herm è s, this elegant uniform was manufactured in our home, Hong Kong, and was the first without a hat.

由著名品牌 Herm è s 设计，这件高贵的制服是香港本土制造，是我们第一套不配帽子的制服。