精母细胞的

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。

To investigate whether the expression of cdc2 and cyclin B1 in spermatogenic cells during spermatogenesis is actually a temperature dependent event, in situ hybridization, Western blotting and immunohistochemistry analysis were used to study the expression of cdc2 and cyclin B1 in normal and cryptorchid testis. Results showed that heat would differentially hurt male germ cells in different developmental stages during spermatogenesis, especially the pachytene primary spermatocytes. Most of spermatogonia in contralateral cryptorchid testis were not harmed fatally by heat as yet, indicating that spermatogonia could resist to beat to a certain extent. In this case spermatogonia could develop to pachytene/diplotene primary spermatocytes, but they could not acquire the ability to complete the transition from mitosis to meiosis, and then appeared to go through apoptosis. Therefore, we could not find the descendants of meiosis: secondary spermatocytes and round spermatids, elongated spermatids and spermatozoon. The abdominal temperature had no significant influence on the transcription of cdc2 and cyclin B1 in the spermatogonia and pachytene/diplotene primary spermatocytes. In normal rabbit testis, cyclin B1 increased in the pachytene/diplotene primary spermatocytes before meiosis and reached its peak in the spermatids.

为了解精子正常发生过程中cdc2和cyclin B1表达的低温依赖性，我们利用原位杂交和免疫组化等方法，研究了正常和隐睾精子发生过程中cdc2和cyclin B1的转录和翻译调控活动，结果表明：（1）热对各阶段的雄性生殖细胞都有损害，粗线期的初级精母细胞尤为敏感，实验性隐睾内的精原细胞尚未完全受到"致命"影响，说明精原细胞对热有一定的耐受性，但即使成为粗线期／双线期初级精母细胞，却未能获得由有丝分裂过渡到减数分裂的能力，呈现不同程度的凋亡，所以在整个切片中找不到源自减数分裂的产物----次级精母细胞、圆形精子细胞，更谈不上长形精子细胞和精子的形成；（2）腹腔高温未明显地影响隐睾精原细胞和粗线期/双线期初级精母细胞中cyclinB1和cdc2的转录，说明高温并不是通过影响cyclin B1和cdc2的转录活动而导致生精过程阻断的；（3）正常兔睾丸组织中，〓在精原细胞和粗线期／双线期精母细胞中均有表达：cyclin B1蛋白在减数分裂前期的粗线期／双线期初级精母细胞中的表达量增加，于变态末期的精子细胞中达高峰。

The results as follows: Chromosomal axial cores formed during leptotene nuclei in spermatocytes of the brown rat, some homologous axial cores were close to each other. The fomation of SCs starts at zygotene, completed at pachytene and disintegrates at diplotene.

在褐家鼠精母细胞的细线期，常染色体轴心（Axial cores， ACs ）已形成，同源轴心在空间上靠近，偶线期SCs 开始形成，到粗线期SCs 完全形成，于双线期SCs 开始解体。

In the last EXP, the testis development during the first mature and the ultrastructure of spermatocytes of were studied. The process of spermatid formation was described.

试验四研究了泰山螭霖鱼精巢在第一次性成熟过程中的发育规律和各级精母细胞的超微结构。

Spermatogenesis was disturbed by high-energy shock wave,in which the formation and differentiation of primary spermatocyte were inhibited.

高能冲击波对生精过程的作用可能是抑制初级精母细胞的形成和分化；多次高能冲击波冲击有诱导睾丸细胞凋亡数量增加的趋势。

The testis index, testis volumes were same as the annual changes of testis mass. The curves of annual variation were all unimodality.2 The spermatogenetic cycle of Myospalax cansus comprises seven stages with significant features: Stage I , from February to April, the testis were at the stage of spermatogonia proliferation. In this period, testis index and the number of spermatogonia began to rise. Other spermatogenic cells had not yet formed; Stage II to III, from March to April, primary spermatocyte meiosis period. The testis index was highest in this stage, and spermatogenic cells were in spermatocyte stage, the primary spermatocyte meiosis generated to secondary spermatocyte; Stage IV, from April to May, spermatocytes continued to split, germ cells appeared in seminiferous tubules; Stage V, in May, sperm formation, spermatids of seminiferous tubules were transformed to spermatozoa, a large number of sperms existed in the lumen; Stage VI, spermatozoa emission period, from May to June, testis index were a significant drop and mature spermatozoa excluded gradually; VII, the testicular activity ceased basically from July to September, November to January of the following year, the spermatogenic activity ceased completely. Therefore, Myospalax cansus are animals of seasonal reproduction, spermatogenesis cycle is discontinuous type.

睾丸系数、体积和重量的年周期变化规律一致，变化曲线呈现单峰型。2甘肃鼢鼠雄性生殖腺的年周期活动由7个特征明显的时期构成：Ⅰ期，2～3月份，精原细胞增殖期，睾丸系数开始上升，精原细胞进行有丝分裂，其他生精细胞尚未形成；3～4月份为Ⅱ～Ⅲ期，初级精母细胞成熟分裂期，睾丸系数达到最大，生精细胞大多处于精母细胞阶段，初级精母细胞减数分裂生成次级精母细胞；Ⅳ期，4～5月份精母细胞继续进行分裂，精细胞在生精小管内出现；Ⅴ期，5月份，精子形成期，曲细精管中精细胞变态成精子，在管腔中存在大量的精子；Ⅵ期，精子排放期，5～6月份，睾丸系数显著下降，成熟精子从生精小管上脱离，逐渐排除；Ⅶ期，精原细胞停滞期，7～9月份睾丸生精活动基本停滞，11～翌年1月，生精活动完全停止。

The apoptosis of 80 mg/kg ﹒ d group was mainly located in spermatogenous cell and first spermatocyte; the apoptosis of 120 mg/kg ﹒ d group was mainly located in spermatogenous cell , first spermatocyte and spermatocyte of the second order; the apoptosis of 240 mg/kg ﹒ d group was mainly located in spermatogenous cell and first spermatocytes, and seemingly, the apoptosis located in first spermatocyte was dominant; whereas the apoptosis of 480 mg/kg ﹒ d group was located in all levels spermatogenic cells.

结果表明：各试验组小鼠生精细胞凋亡指数随着浓度的升高有增加的趋势，而且与对照组差异显著（ P ＜0.05或 P ＜0.01）。80 mg/kg · d 组凋亡细胞主要定位于精原细胞和初级精母细胞；120 mg/kg · d 组凋亡细胞主要定位于精原细胞、初级精母细胞和次级精母细胞；240 mg/kg · d 组凋亡细胞主要定位于精原细胞、初级精母细胞，以初级精母细胞为最多；而480 mg/kg · d 组凋亡细胞定位于各级生精细胞。

Stage I of both male and female stone flounder appears only once in all its life, and the germ cells are comprised by spermatogonia or oogonia. The gonad from Mar to Aug keeps at stage II. The gonad index of testis at this stage is 0.037%, and the amount of spermatogonia is increased quickly. There is some linear germ plasm in the cytoplasm of spermatogina. In ovary at this stage it is mostly composed by oocyte of phase 2 which the character is the appearance of yolk nucleus, and no zona radiate in membrane. The mean GI of ovary is 1.95%. From Sep to Oct gonad is at stage III which testis is composed by lots of spermatogina and few spermatocytes, and the mean GI of testis at this stage is 0.086%. In ovary the ooctyes at phase 3 are in dominate position, the yolk nucleus disappear. And the GI of this stage is 3.35%. Both testis and ovary are at stage IV in Nov. hi testis the germ cells are in spermiogenesis, and the mean GI is 0.93%. hi ovary the oocytes are mostly at phase 4, which are filled in the cytoplasm with vitellin granule, and the zona radiate in membrane begins to formation. Nucleus moves to one side of the oocyte gradually. The mean GI of ovary at this stage is 9.37%.

在每年的3月-8月期间性腺处于Ⅱ期，此期精巢中精原细胞明显增多，胞质局部可见有线状的生殖质存在，平均成熟系数为0.037％；卵巢中以2时相卵母细胞为主，可见细胞质中出现强嗜碱性的卵黄核，细胞外由一层滤泡细胞包围，但尚无放射带，平均成熟系数为1.95％。9月-10月期间性腺处于Ⅲ期，此期精巢中仍有大量精原细胞，同时可见部分精母细胞，平均成熟系数为0.086％；卵巢中以3时石鲜孟加限加$玩印面n洲匆s性腺发生、分化及发育的周年变化相卵母细胞为主，细胞质中的卵黄核己消失，平均成熟系数为3.35%。11月性腺处于IV期，此期精巢内精细胞正处于不同的形成过程中，平均成熟系数为0.93%；卵巢中以4时相卵母细胞为主，胞质中充满染成桔红色的卵黄颗粒。

In spermatocytes, the proteins of lower MW have high affinity to the A-T repetitive DNA fragment, but it is only in round spermatids that some proteins of higher 40kD have strong affinity.

Southwestern blot显示精母细胞的低分子量蛋白对A-T重复序列的吸附能力强，而只有早期精子细胞的部分高分子量蛋白对该序列具有很强的亲和力。

The results showed that after 2 h of culture in MEM the chromosomes of oocyte were seperated to form telophase I while a small spindle was observed around chromosomes of primary spermatocyte. However, two clear spindles were observed in the oocytes cultured in CB containing MEM. After further culture, the chromosomes of both primary spermatocyte and oocyte intermingled and formed one large spindle.

在无CB的培养液中培养的卵母细胞培养2小时后，卵母细胞已经进入第一次减数分裂的后期，染色体开始被拉向两极，而精母细胞的MI纺锤体才刚刚形成，虽然继续培养两者染色体可以合二为一并形成一个纺锤体，但是有些染色体发生滞后；当卵母细胞在含有CB的培养液中培养2小时后，在卵母细胞内形成两个相似大小的MI纺锤体，进一步培养形成一个大的纺锤体，染色体正常。

However, as the name（read－only memory）implies, CD disks cannot be written onorchanged in any way.

然而，正如其名字所指出的那样，CD盘不能写，也不能用任何方式改变其内容。

Galvanizes steel pallet is mainly export which suits standard packing of European Union, the North America. galvanizes steel pallet is suitable to heavy rack. Pallet surface can design plate type, corrugated and the gap form, satisfies the different requirements.

镀锌钢托盘多用于出口，替代木托盘，免薰蒸，符合欧盟、北美各国对出口货物包装材料的法令要求；喷涂钢托盘适用于重载上货架之用，托盘表面根据需要制作成平板状、波纹状及间隔形式，满足不同的使用要求。