卵球

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 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。

Usually the cytoplasm in this region is incorporated into future endoderm cells .

可是在植物极也有产生小卵裂球的情况。

Laser scanning confocal microscopy FRAP GJIC rabbit blastomeres

激光扫描共聚焦显微镜FRAP ； GJIC兔胚；胎卵裂球

Compared with the female fishes at postspawning stage, the GnRH contents of olfactory bulbs and pituitary at intersexual stage were in creased.

与排卵后雌鳝相比，间性期黄鳝以嗅球和垂体GnRH含量变化明显，都呈上升趋势。

Two fragment of Etmic-2 was cloned and sequenced by PCR using genomic DNA as template from sporulated oocysts and the second generation merozoite of Eimeria tenella.

本文利用PCR技术，分别从柔嫩艾美耳球虫的第二代裂殖子和孢子化卵囊基因组DNA中扩增出微线蛋白EtMIC-2基因序列，并进行了克隆和核苷酸序列测定。

Tenella infection, nitric benzene could interdict the entering of the parasite, it could ease the injury of the host cell and have certain protection to the chicken body ,but with the developing of the disease ,its function descend,but the time of the oocyst discharging was prolonged.

tenella病发生的早期，硝苯地平可以阻断球虫的侵入，减轻宿主细胞的损伤，对鸡体有一定的保护力，但随着疾病的发展，其作用下降，但使E。 tenella卵囊的排出时间推后。

Eleven geographical strains of Eimeria maxima were tested for their ability to induce protection against homologous and heterologous strains, assessed by weight gain, lesion score and reduction in oocyst production.

文章摘要：用平均增重和病变记分或卵囊减少率等为试验指标，对11株巨型艾美耳球虫的免疫原性进行了分析。

John Robbins lives with his family in Santa Cruz, California.

约翰罗宾和家人居住在加利福尼亚州的圣克鲁斯县。

The international background is mainly the economic ties among different nations tented to be widen and deepen at the peace and development times.

国际背景主要是和平与发展时代条件下的世界各国经济贸易联系的日益加深。