精子发生的

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。

The ultrastructure of spermatogenesis and spermatozoon of Pollicipes mitella was studied.

对龟足精子发生和成熟精子的超微结构进行了研究。

Cloning of spermatogenesis related genes and further functional study are very important to the elucidation of molecular mechanism involving in spermatogenesis and spermiogenesis process.

克隆睾丸精子发生相关基因并研究其功能，对于揭示精子发生过程中减数分裂和变态的分子机制，对于临床男性不育的诊断和治疗以及男性分子节育等均具有重要的意义。

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。

Spontaneous germ cell death is very important for the removal of germ cells and control of the quantity and quality of sperm. But excessive germ cell death will lead to diminish spermatogenic function and decrease the quality and quantity of sperm. Excessive germ cell death triggered by various regulatory stimuli, including deprivation of gonadotropins and intratesticular testosterone or by estradiol treatment in rats via apoptosis.

生精细胞凋亡是哺乳动物精子发生过程中的一个显著特点，其生理性凋亡对于去除受损的生精细胞，控制细胞数量和保证精子的质量具有重要意义，但生精细胞的过度凋亡可引起生精功能低下，使精子的数量和质量降低。

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。

Sinensis could be divided into 5 stages, includi ng t he spermospore proliferation stage, the primary spermatocyte stage, the secondar y spermatocyte stage, the spermateliosis stage and the spermiotiliosis stage.

在整个精子发生过程中，N-乙酰半乳糖复合物出现于精原细胞期，并于精母细胞期发生明显的修饰和变化，精子形成期和成熟期没有N-乙酰半乳糖复合物的表达。

The distinctions of spermatogenesis and sperm morphology between Solen grandis and Solen strictus were also discussed.

大竹蛏与同属的长竹蛏精子发生和精子超微结构存在差异。

Up to now, scientists have estimated that about 3500~5000 mRNAs were retained in human ejaculated spermatozoa, and indicated that they may play important roles in the process of chromosome recombination, gene imprinting and spermatogenesis.

越来越多的研究发现成熟精子中存在有大量而复杂的mRNA群体，到目前为止，科学家们估计人正常射出的精子当中有3500-5000多种RNA，并且认为它们可能在染色体重新组装、基因印迹及精子发生过程中起着重要的作用。

Strong expression of nanos 1 mRNA was detected in spermatogonia and relatively weaker signal was found in primary spermatocytes but no nanos 1 mRNA expression was observed in spermatids. The results suggested that nanos 1 may play an important role in maintenance and functioning of the germline stem cell—oogonia and spermatogonia.

在斑马鱼精子发生中， nanos1 mRNA可在精原细胞和初级精母细胞中检测到。nanos1 mRNA的阳性信号在精原细胞中极为强烈，在初级精母细胞中较为微弱，而精子细胞中没有阳性信号。

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。