鸡胚发育期中细胞与卵黄对放射性硫(S^(35))—蛋氨酸摄取的对比研究

AN AUTORADIOGRAPHIC STUDY ON THE UPTAKE OF RADIOSULPHATE(S^(35))——METHIONINE IN THE EMBRYONIC TISSUE VERSUS YOLK MATERIAL OF THE DEVELOPING CHICK EMBRYO

绪言在我们以前的报告中[1,2]曾经指出鸡胚卵黄球在胚胎发育过程中和在离体培养环境下不具“活质”的特性而逐渐分解和液化成为颗粒或小球滴状态为胚胎所吸收;位于胚下腔中的卵黄球在位置上虽然和胚盘深层细胞邻接或混在一起,但并不能演变为内胚层细胞;进入于内外二胚层间的卵黄球也和血岛的形成无直接关系。

Saline solution(0.9%),containing 5—10μc of radiosulphate(S^(35))——methio-nine(0.2—0.4ml)was injected into the yolk sacs of unincubated to 8—day chickembryos.Fixation was made after 6—24 hours of incubation in various fixa-tives(Bouin's,Carnoy's,neutral formalin,methyl or 95%ethyl alcohol).Mostof the embryos were stained in toto with Ehrlich's hematoxylin and eosin,butsome were stained with Wallback's Giemsa mixture of Mallory's modificationafter sectioning.Serial sections(5—7μ)were used for contrast autoradiography.It was observed that a remarkable radiosulphate uptake in the embryonic tissuefollows the cellular pattern and was concentrated in proportion to the cellulardensity of tissue,the tracer is noticeable in the autographs by itsβ-tracts andgrains over cytoplasm and nuclei of cells;while the yolk spheres entered thesubgerminal cavity and in the space between ectoderm and entoderm in thegerm wall were not radioactive.The blood vessels,erythroblasts and the mul-tinucleated syncytium,including the so-called“columnar epithelial cells”of theyolk sac lining and of the germ wall,also show high incorporation of radio-sulphate,but not at all in the yolk material.Furthermore,the yolk granules,droplets of unequal size with positive Feulgen reaction,and those even withan appearence of pyknotic nucleus in the“transitional zone”of yolk sac liningas described in the previous investigation,also show no tracer uptake.It isobvious,that radiosulphate is not incorporated into the yolk material.Fromthe above,it may be assumed that no protein synthesis or resynthesis(“Об-новления”)occurs in the yolk sphere.These results are in good agreementwith our previous findings and afford further evidence to the conclusion that theyolk spheres are not a living substance incapable of developing into embryoniccell.