四体

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。

Tetraploid organisms may arise by the fusion of two diploid gametes that have resulted from the nondisjunction of chromosomes at meiosis, or by nondisjunction of the chromoosomes during the mitotic division of a zygote.

四倍体的产生可能是由于两个二倍体配子发生融合，这种二倍体配子又是在减数分裂中染色体不发生分离而形成。四倍体也可能因为受精卵进行有丝分裂时染色单体未发生分离而形成。

The novel complex (1) in which both benzylic nitrogens and heteroaromatic ones to the same metal ion with the rigid ligand imposed by the large heteroaromatic moiety first time was synthesized; a 2: 1 (ligand: metal ions) type complex which has steric resistance and strong thermochemical driving force was obtained. The crystal structures of characteristic ligand (LA4) and complexes (4, 7, 10), in which one cell includes two moieties: there exist minute difference in coordinated bonds and angles despite the same metal ions with the same ligand, were obtained. It shows that several stable conformation in one complex cell.

首次合成了含邻菲罗啉的具有较大刚性的四氮配体中四个氮原子全部与同一金属离子配位的配合物的晶体结构；得到了一个在空间上存在位阻作用的配体与金属离子2：1结构的晶体；解析了具有特色的一个配体（LA4）和三个配合物（4、7和10）的晶体结构，其中的配体与金属离子的配位作用显示出细微的差异，表明在同一金属配合物的晶胞中，可以同时存在着多个稳定的构象。

The cytogenetics of interspecific hybrids among the four cultivated cotton species were studied in this paper and results are as follows: The diploid interspecific hybrid (G. arboreum×G. herbacium) F〓 had a four-chromosome-ring at the meiotic metakinesis. The synapses of tetraploid hybrid (G. hirsutum ×G. barbadense) F〓 was found to be regular, which mainly formed bivalents, sometimes some univalents, multivalents and chromosome bridge.

四个栽培棉种间杂交种F〓的细胞学观察结果表明，F〓减数分裂中期Ⅰ，形成一个环状四价体，直接证明了亚洲棉与草棉之间存在一对相互易位；F〓减数分裂中期Ⅰ联会基本正常，主要形成二价体，偶尔出现一些单价体和多价体，以及染色体桥。

In order to obtain viable tetraploids, which remains a major challenge worldwide, research on spindle organization and chromosome behavior was carried out mainly in zhikong scallop, Chlamys farreri, a typical commercially important species which is being cultured in North China Sea. Immunofluorescent technique and laser scanning confocal microscopy has been developed for observation of both microtubule organization and chromosome segregation. Orcein squash method was also used for chromosome observation. A series of complicated configurations of the meiotic spindle and associated patterns of chromosome segregation, including tripolar and seperated bipolar segregation, were found in developing eggs following the inhibition of the first polar body.

为了攻克可存活四倍体人工培育技术的国际性研究难题，本研究选取了我国北方海区的典型经济贝类栉孔扇贝为主要研究对象，建立了一套免疫荧光染色和激光扫描共聚焦显微技术，结合使用染色体地衣红压片观察技术，对第一极体受抑制的受精卵的减数分裂纺锤体装配、染色体分离动态进行了研究，发现了一系列特殊的纺锤体装配及相应的染色体分离行为，包括三极分离、独立二极分离等分离类型，从亚细胞水平上阐明了四倍体形成的细胞学机理。

The improved L.D.Cua method was used to induce tetraploid of Trichosanthes kirilowii Maxim. The suitable treating time of 0.2% colchicine, the morphology characters and cytology identification between plants of diploid and obtained tetraploid were studied.

采用改良L.D.Cua法诱导短把栝楼获得四倍体，研究了0.2%浓度的秋水仙碱诱导短把栝楼染色体倍性变异的最佳处理时间、四倍体栝楼与原栝楼的形态特征及其四倍体与二倍体的细胞学鉴定。

Four bidentate NS ester ligands, two bidentate NS amide ligands, tridentate MBPA and tetradentate BMBPA ligands have been synthesized.

合成了四种含有酯基的NS二齿配体-CYE系列物，两种含有酰胺基的NS二齿配体，三齿配体MBPA和四齿配体BMBPA。

Pitardii,all from the Jinshajiang Valley of Yunnan and Sichuan, were cytologically studied in this work. Among 34 populations of C.reticulata studied here, 21 were found to be tetraploids (2n=60), 11 hexaploids (2n = 90), and the remaining two diploids (2n = 30). Tetraploid was reported in C. reticulata for the first time and its karyomophology was studied.

reticulata及其两个近缘种(怒江山茶C.saluenensis和西南山茶C.pitardii)进行了细胞学研究。34个居群的云南山茶花中，21个居群是四倍体类型(2n=60)，11个居群是六倍体类型(2n=90)，另2个居群为二倍体(2n=30)，云南山茶花的四倍体类型为首次发现，并且进行了核形态研究。

I didn't watch TV last night, because it .

昨晚我没有看电视，因为电视机坏了。

Since this year, in a lot of villages of Beijing, TV of elevator liquid crystal was removed.

今年以来，在北京的很多小区里，电梯液晶电视被撤了下来。