Palén K, Thörneby L
J Embryol Exp Morphol. 1981 Feb;61:175-90.
Chick embryos were treated in ovo and in vitro with L-phenylalanine from the intermediate streak stage (Hamburger & Hamilton stage 3, 12-13 h of incubation) to the 7-somite stage (H & H stage 9, 29-33 h of incubation). Treatment in ovo resulted in a large number of embryos developing somite blocks, i.e. imperfectly segmented somites. In embryos treated at an early developmental stage (12-21 h of incubation), the blocks of unsegmented somite mesoderm occurred mostly in the somite pairs 1-5, whereas treatment that began at a later stage (24-30 h of incubation) caused blocks in the somite pairs 5-10, i.e. the appearance of blocks of unsegmented somite mesoderm is correlated in time with the onset of the treatment. No difference regarding mitotic indices could be distinguished between normally segmented somites and blocks of unsegmented somite mesoderm. Autoradiography based on tritiated L-phenylalanine showed no regional differences in labelling of the chick embryo body. Electronmicroscopical observations indicate a slightly suppressed formation of microvilli in the cells of the unsegmented mesoderm blocks compared with cells in normally segmented somites. The observed disturbances are probably caused by a suppressed yolk granule decomposition in the developing somite cells. The experiments in vitro support the findings in the in ovo material; at the same time, they reveal an unexpectedly slow diffusion of L-phenylalanine through the vitelline membrane.
从原条期（汉伯格和汉密尔顿第3期，孵化12 - 13小时）到7体节期（H&H第9期，孵化29 - 33小时），对鸡胚进行了卵内和体外L - 苯丙氨酸处理。卵内处理导致大量胚胎发育出体节块，即不完全分割的体节。在发育早期（孵化12 - 21小时）处理的胚胎中，未分割的体节中胚层块大多出现在第1 - 5对体节中，而在后期（孵化24 - 30小时）开始的处理则导致第5 - 10对体节出现块，即未分割的体节中胚层块的出现与处理开始的时间相关。在正常分割的体节和未分割的体节中胚层块之间，有丝分裂指数没有差异。基于氚标记L - 苯丙氨酸的放射自显影显示，鸡胚身体的标记没有区域差异。电子显微镜观察表明，与正常分割体节中的细胞相比，未分割的中胚层块细胞中的微绒毛形成略有抑制。观察到的干扰可能是由于发育中的体节细胞中卵黄颗粒分解受到抑制所致。体外实验支持了卵内材料的研究结果；同时，它们揭示了L - 苯丙氨酸通过卵黄膜的扩散出乎意料地缓慢。
