Purpose embryonic stem cells ( escs ) which are from the inner cell mass ( icm ) of preimplantation blastula are pluripotent . neurons are considered as terminally differentiated cells that can not divide nor proliferate after injury 目的胚胎干细胞( embryonicstemcells ， escs )来源于着床前胚胎的囊胚期内细胞团( innercellmass ， icm ) ，具有发育全能性。
2.
The fertilized egg entered the 4 - cell stage in 2hlomin , and the 8 - cell stage in 2h20min . the fertilized egg entered the 32 - cell stage in 3hl2min , and the cells distributed in different layers . the fertilized egg entered the multi - cell stage in 4h05min and the early blastula stage in 5h 1小时30分受精卵开始第一次分裂； 2小时10分进入4胞期； 2小时20分进入8胞期： 3小时12分进入32胞期，细胞出现分层现象； 4小时05分进入多细胞期； 5小时进入高囊胚期； 6小时50分进入低囊胚期。
3.
The primary results showed : using m199 as diluents containing 20 % bovine serum , it is better to freeze the cells slowly freezing at fist then increase freezing speed ( for example , from 0 to - 6 freezing speed is about - 0 . 05 a minute , from - 6 to - 40 , freezing speed is about - 0 . 5 a minute ) , studies on effect of various concentration of dmso demonstrate that about 12 . 5 % dmso gave the highest post - thaw percentage of viable cells . the concentration of bovine serum had no different effect on the percentage of the viable embryo cells of misgurnus auguillicaudatus . the embryo cells derived 6 from the later stage of blastula offish is more resistant to the cryogen than the cells of early stage of blastula . the cells preserved in liquid nitrogen at - 196 were thawed and cultivated , a few cells were found adhere to the surface of culture vessel when the percentage of viable cell was more than 30 % . the cells in only two culture vessels were found to proliferated and gave rise to many small morphologically undifferentiated cells 研究初步表明:以细胞培养液m199 (含2既的小牛血清，常规量双抗)为冻存稀释液对泥鳅胚胎细胞冷冻保存宜采取先慢后快的方式(例如，从0一一6 ，冻存速度为一0 . 05 / min ，再以一0 . 5 / min的速度从一6一一40 ) ; dmso的保护效应浓度为12 . 506左右;小牛血清的浓度对泥鳅胚胎细胞的成活率影响不明显;囊胚晚期细胞抗冻性比中早期强;通过对不同批次的冻存细胞解冻培养，解冻后成活率为30 %以上细胞培养数天后均有少数细胞贴壁，但只发现两瓶培养细胞有明显增殖现象产生许多未分化的小细胞。
4.
Using m199 containing 20 % calf bovine serum and 11 % dmso as the diluent and by the methods using in cryopreservation of embryo cells of misgurnus auguillicaudatus , two groups of cells derived from blastula of grass carp were preserved in liquid nitrogen at - 196 . after 6 days cryopreservation , one group of cells were thrawed and the percentage of viable cell was about 72 % ; the other , cryopreserved for 13 days , was 52 以细胞培养液m199 (含20 %的小牛血清)为稀释液， dmso的浓度为11 % ;与泥鳅胚胎细胞冷冻保存方法一样，采取先慢后快的方式，冷冻保存两组草鱼囊胚晚期细胞于一1 %的液氮中。第一组冷冻保存6天后解冻，成活率为72 % ，第二组冷冻保存13天后解冻，成活率为520 / 0 。
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G - banding the gtg banding ( g - banding ) was carried out by the standard trypsin method with slight modification , which works well for protochordate because a good number of reproducible g - bands are consistently obtained from the embryonic cells of late blastulae and early gastrulae of amphioxus b . belcheri tsingtauense G带型用稍作修改的标准的胰酶显带技术，进行gtg带纹的显示，它们能较好地显示头索动物青岛文昌鱼的晚期囊胚和早期原肠胚的中期染色体的g带，并且重复性好。
