精子的

It is a complex process involving cell division, differentiation and interaction between cells in the microenvironment of the seminiferous tubule.

睾丸生精小管中的生精细胞先后经过三个阶段的变化：精原细胞的增殖，精母细胞的减数分裂和精子细胞的变态过程，最终产生成熟的精子。

PH-20 is a traditional sperm membrane antigen,and it is a glycophosphatidylinositolanchored hyaluronidase.

PH-20(posterior head 20)作为传统的精子膜抗原，是由磷脂酰肌醇(glycophosphatidylinositol，GPI)锚定的膜结合型透明质酸酶，最适PH值呈中性，它分布于精子表面浆膜和顶体内膜，是一种透明质酸酶诱导信号转导的受体和识别透明带的受体。

Spag4l and Papolb were down-regulated from pachytene spermatocytes to elongating spermatids, decreasing 45% and 34%, respectively. The results not only demonstrate the stage-specific expression of these genes, but also provide new data for further investigations into the functions of these specific genes during spermatogenesis.

结果提示，被检测的基因具有明显的阶段特异性表达特征，为深入研究这些基因在小鼠精子发生过程中的作用提供了新资料，同时也为荧光定量PCR技术在精子发生相关基因定量表达研究中的可行性提供了充分例证。

Two polar nuclei move to the micropylar end before sperm is released in a gap between the egg cell and central cell and subsequently taking off cytoplasm one after another. The sperm nucleus moving to the egg nucleus runs faster than the one to the polar nuclei. It fuses with the polar nuclei that are moving towards the antipodal cells at the chalazal end.

精子释放前，两极核移向卵细胞的合点端；两精子释放于卵细胞与中央细胞的间隙后，先后脱去细胞质，然后分别移向卵核和极核，移向卵核的精核快于移向极核的精核；精核与两极核在向反足细胞团方向移动的过程中完成雌雄核融合。

Two polar nuclei move to the micropylar end before sperm is released in a gap between the egg cell and central cell and subsequently taking off cytoplasm one after another. The sperm nucleus moving to the egg nucleus runs faster than the one to the polar nuclei. It fuses with the polar nuclei that are moving towards the antipodal cells at the chalazal end, Images showed the fusion process of male and female nuclei and polyspermous fertilization.

精子释放前，两极核移向卵细胞的合点端；两精子释放于卵细胞与中央细胞的间隙后，先后脱去细胞质，然后分别移向卵核和极核，移向卵核的精核快于移向极核的精核；精核与两极核在向反足细胞团方向移动的过程中完成雌雄核融合。

These findings suggest that spermiogenesis in S.schall is a synapomorphic type derived from types Ⅰ and Ⅱ spermiogenesis which are common among other teleosts and is closely similar to type Ⅲ spermiogenesis that is previously described in the Nile catfishes Chrysichthys auratus and Malapterurus electricus.

但是，正如文献所报道过的另两种尼罗河鲶——金鯵和电鲶中的情况一样，盾头歧须的精子发生与类型Ⅲ的精子发生过程更为相似。

Objective To detect the abnormal YRRM gene in azoospermia and to explore the pattern of YRRM gene in Chinese men.

目的 探索无精子症因子基因的候选基因之一YRRM基因在无精子症患者中的异常，了解中国人群的YRRM基因的形式。

Methods Spermatocytes, early stage spermatids and the later stage spermatids were separated from the adult rat testis by the velocity gravitative sedimentation technique. Using the whole mount electron microscopy, SDS-PAGE and Southwestern blot, the morphology, components of NM-L-IF and the relationship between an A-T repetitive DNA fragment and the proteins of NM-L-IF in those cells were analyzed.

利用整装电镜技术、SDS-PAGE和Southwestern blot等技术观察与分析经单位重力沉降法分离的大鼠精母细胞、早期精子细胞和晚期精子细胞的NM-L-IF的形态结构、蛋白组成及其与A-T重复序列的相互关系。

These findings suggest that spermiogenesis in S.schall is a synapomorphic type derived from types Ⅰ and Ⅱ spermiogenesis which are common among other teleosts and is closely similar to type Ⅲ spermiogenesis that is previously described in the Nile catfishes Chrysichthys auratus and Malapterurus electricus.

但是，正如文献所报道过的另两种尼罗河鲶--金鲿和电鲶中的情况一样，盾头歧须的精子发生与类型Ⅲ的精子发生过程更为相似。

A worldwide decline in the number of wild salmonids calls for strategies to restore endangered populations.

关于《Nature》：精子移植的新应用的原因，关于《Nature》：精子移植的新应用的相关知识。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。