中华大蟾蜍(Bufo bufo gargarizans)孵化腺细胞的研究

ON THE HATCHING GLAND CEEL OF THE TOAD (BUFO BUFO GARGARIZANS) EMBRYO

中华大蟾蜍胚胎在尾茅期孵化,其孵化腺细胞(HGC)是从神经管期的表皮外胚层中分化的,呈大瓶状,主要分布于头的前额部和背中线,少量分布于躯干部的背中线。电镜观察表明,神经管期 HGC 通常是几个相连一起,游离面有许多微绒毛,细胞内顶区有大量分泌颗粒,次顶区有许多色素颗粒、粗面内质网和高尔基体;分泌颗粒是由粗面内质网合成,高尔基体浓缩加工而成。随孵化酶的分泌,HGC 表面逐渐缩小,而微绒毛增长和增密。直至变态前退化的 HGC 尚未完全消失。

The embryo of Bufo bufo gargarizans hatched at the tailbud stage(st. 17).During the hatching process,the head of the embryo sticked out first from the fertilization envelope,and the whole embryo followed. Light microscopic examination showed that at the tailbud stage,the large,flask-shaped epidermal cells,designated as the hatching gland. cells(HGC),were mostly distributed over the frontal region,and a small number of them were located along the dorsal midline of the embryo. Transmission electron microscopic examination skowed that the HGC of the embryo at the st.17 was characterized by the presence of many mi- crovilli on the apical surface,a number of apically localized,membrane- limited secretory granules,well-developed Golgi complexes and an abund- ance of nough-surface endoplasmic reticula.There were a lot of soc- retory granules in HGC until the muscular response stage(at.18).Scanning electron microscopic examination revealed thad the first sign of the HGC differentiation was the appearance of microvilli on the free surface of epidermal cells at the neural tube stage(st.16).The free surface area of HGC decreased and microvilli became more and longer at the st.17, than that at the st.16.After hatching,the HGC farther decroased their free surface area.