原肠

The inpocketed vegetal pole cells develop into a sheet of cells which grows upward and eventually encloses a cavity, the archenteron

内褶的植物极细胞生成一片向上生长的细胞，并最后围成一个腔，即原肠。

A independent life individuality is finally formated from singlecell ferti1ized egg throngh egg cleavage、morula stage、blastocoele stage、protogaster stage and orange etc, and concerned in major basal questions of development and gene expression.

单细胞的受精卵通过卵裂、桑椹胚、囊胚、原肠胚及器官的发生等，最后形成一个能独立生活的个体，涉及发育和基因表达的许多基本问题。

Result The embryonic development of Silnrus asotus in Dongting Lake was divided into 7 stages, namely, blastoderm stage, cleavage stage, blastula stage, gastrula stage, neurula stage, organogenesis stage and pre-hatching stage.

结果］洞庭黄鲶的胚胎发育过程可分为胚盘期、卵裂期、囊胚期、原肠期、神经胚期、器官形成期和出膜期7个阶段。

The fourth milestone was in the embryonic stage of development . Vertebrates and echinoderms began to develop differentiated mouth structures from secondary openings off the blastopore ( an initial opening in the embryonic cavity ).

第四个重要事件出现动物的胚胎发育期，脊椎动物和棘皮动物开始在胚孔（即动物早期胚胎原肠的开口）相对的一端另行开口，并最终发育为成体的口。

The in growth and curl in g in ward of a group of cells,as in the formation of a gastrula from a blastula.

内长一组细胞的内部或向内生长，如从囊胚到原肠胚的生长过程

The ingrowth and curling inward of a group of cells,as in the formation of a gastrula from a blastula.

内长一组细胞的内部或向内生长，如从囊胚到原肠胚的生长过程

The outer layer of a blastula that gives rise to the ectoderm after gastrulation.

外胚层囊胚的外层，在原肠胚形成之后生后外胚层组织

The formation of a gastrula from a blastula by invagination.

外胚层囊胚的外层，在原肠胚形成之后生后外胚层组织

3The sensitivity of organisms on toxin differs at different development stage: in common, the embryo before blastula was more sensitive to toxin.

3生物不同发育阶段对毒物的敏感性不同：一般来说原肠期之前的胚胎对毒物较敏感。

The rearrangement of the blastula into a three-dimensional organism with inner middle and outer layers occurs during gastrulation.

在原肠胚形成过程中，囊胚重新排列，形成包括内层，中层，外层的三围组织。

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。