Selwood L, Smith D
Department of Zoology, La Trobe University, Bundoora, Victoria, Australia.
Mol Reprod Dev. 1990 May;26(1):53-62. doi: 10.1002/mrd.1080260109.
The first six normal stages of cleavage and blastocyst formation in vitro of the brown antechinus and the stripe-faced dunnart are described based on 429 embryos from 37 dunnarts and 143 embryos from 32 antechinus and an information from previous studies. Embryos were cultured in Dulbecco's modified Eagle's medium with high glucose and 10% foetal calf serum at 35 degrees C and 5% CO2 in air. Seven antechinus and 18 dunnart embryos were cultured in Rose chambers and filmed by time-lapse cinematography, with an exposure of 0.2 sec and at a rate of 1 frame/30 sec. A rim of zona was formed around the yolk mass during early cleavage. Blastomeres attached to this rim, ensuring that the zona in the hemisphere containing the yolk mass was the first to be lined by blastomeres during blastocyst formation, which is completed at about the 32-cell stage. Two foci were established during cleavage. The descendants of the first cell to divide at the four-cell stage included, at both the fourth and fifth division, the first cell to divide and the cell with the shortest cell cycle time and had the shortest average cell cycle time at each division. The descendants of the cell opposite the first cell to divide at the four-cell stage included, at both the fourth and fifth divisions, the last cell to divide and the cell with the longest cell cycle time and had the longest average cell cycle time at each division.
基于37只袋鼬的429枚胚胎、32只褐袋鼩的143枚胚胎以及先前研究的信息，描述了褐袋鼩和纹面袋鼬体外发育的前六个正常卵裂阶段和囊胚形成过程。胚胎在含高糖的杜氏改良 Eagle 培养基和10%胎牛血清中，于35℃、5%二氧化碳的空气中培养。7只褐袋鼩和18只袋鼬的胚胎在罗斯培养室中培养，通过延时摄影拍摄，曝光时间为0.2秒，拍摄速率为每30秒1帧。在早期卵裂过程中，卵黄团周围形成了一层透明带。卵裂球附着在这层透明带上，确保在囊胚形成过程中，含有卵黄团的半球中的透明带首先被卵裂球覆盖，囊胚形成在大约32细胞阶段完成。在卵裂过程中形成了两个细胞群。在四细胞阶段第一个分裂的细胞的后代，在第四次和第五次分裂时，包括第一个分裂的细胞和细胞周期最短的细胞，并且在每次分裂时平均细胞周期时间最短。在四细胞阶段与第一个分裂的细胞相对的细胞的后代，在第四次和第五次分裂时，包括最后一个分裂的细胞和细胞周期最长的细胞，并且在每次分裂时平均细胞周期时间最长。
