双线期

Due to the deficiency of cyclin B1 and 〓, spermatogonia and pachytene/diplotene primary spermatocytes in contralateral cryptorchid testis were unable to form MPF, and therefore, they could not accomplish their nuclear division, and became arrested at the transition stage from mitosis to meiosis (G2/M phase). We also found that testosterone could regulate the cyclin B1 expression in spermatogenic cells.

由于cyclin B1和〓的缺失，粗线期/双线期初级精母细胞中的MPF无望形成，从而导致生精细胞分裂停滞在由有丝分裂向减数分裂过渡的G2/M相；（5）睾酮可在翻译水平上调控阴囊内睾丸生精细胞cyclin B1蛋白的表达。

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。

Prophase may be divided into successive stages termed leptotene, zygotene, pachytene, diplotene, and diakinesis.

前期可被分为连续的阶段：细线期、偶线期、粗线期、双线期和终变期。

ResultsAll dividing stages （leptotene, zygotene, pachytene, diplotene stages and diakinesis） were observed in low power lens and those divi- ding stages increased greatly compared with the routine method.

结果 低倍镜下可见细线期、偶线期、粗线期、双线期、终变期细胞，各期细胞染色体分裂相较常规制片明显增加。

Oocytes of humans and animals often have long remained at meiotic diplotene.

人和动物的卵母细胞常长期停留在减数分裂的双线期。

Centromeres could be identified easily on the bivalents at diplotene, so it was convenient to analyse the karyotype.

结果表明，日本沼虾染色体数n=52，2n=104，据双线期二价体的相对长度、着丝点位置以及形态诸方面的特点分析了核型，共分为A，B，C，D4个染色体组，核型组成是N=37M+4ST+11T；初级精母细胞减数分裂前期I可分为细线期/偶线期、粗线期、双线期和终变期5个时期，双线期的二价体存在弥散阶段，核仁明显，且双线期二价体着丝点清晰，给核型分析带来了方便。

Obviously, large amounts of cyclin B1 existing in spermatids has no effect on adjusting the activity of 〓 kinase, which may be just a signal of the end of cell division and/or a necessary factor for the initiation of the metamorphosis of spermatids. Abdominal high temperature inhibit efficiently the translation of cyclin B1 and 〓 in the spermatogonia and pachytene/diplotene primary spermatocytes.

显然，精子细胞中大量存在的cyclin B1蛋白不会起到调节〓激酶活性的作用，而是作为一种细胞分裂完成的信号，为启动精子细胞变态所必需；（4）腹腔高温使粗线期/双线期初级精母细胞中cdc2和cyclin B1转录本的翻译受阻。

It was a new mousegene in GenBank and named as SRG-L(spermatogenesis related gene expressed in the latestages of spermatogenic cells). The sequence of this cDNA has been deposited in GenBankwith the Accession No. AY352586. 2. Analyses of expression characteristics of SRG-L during mouse spermatogenesis.The results of RT-PCR and Northern Blotting indicated that no expression signal of thisgene could be observed in primitive type A spermatogonia and type B spermatogonia. Asignal first appeared in diplotene/pachytene spermatocytes, and was significantlyintensified in round spermatids and elongating spermatids, findly went down to beundetectable in mature spermatozoa.

RT-PCR和Northern Blotting分析表明：该基因在早期A型和B型精原细胞中不表达，从双线期初级精母细胞阶段开始表达并逐渐上调，在粗线期初级精母细胞、圆形精子细胞及长形精子细胞中均检测到高水平的mRNA，但在成熟精子中消失，具有明显的阶段特异性表达特征，并且组织特异性表达分析显示该基因在睾丸组织中的呈高表达。

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。

At zygotene,t he SC formation initiated at multiple sites in each bivalent but the regions nea r telomeres were preferred.SCs were shortened with development of SCs.Initiation of new SC and extension of existing SC occured simultaneously,and pairing in di fferent bivalents of a nucleus was not synchronised.

结果表明，小麦SC以多点式起始方式于偶线期开始形成；随SC的发育，新的SC形成和已有SC片断的延伸并存；此外，在同一核内不同二价体之间，染色体配对和SC形成并不同步；SC成熟于粗线期，而以破碎方式解体，消失于双线期。

This one mode pays close attention to network credence foundation of the businessman very much.

这一模式非常关注商人的网络信用基础。

Cell morphology of bacterial ghost of Pasteurella multocida was observed by scanning electron microscopy and inactivation ratio was estimated by CFU analysi.

扫描电镜观察多杀性巴氏杆菌细菌幽灵和菌落形成单位评价遗传灭活率。