ELECTRON MICROSCOPIC STUDIES ON THE CHROMATIN OF BLASTODERM NUCLEI AND YOLK GRANULES BENEATH BLASTODERM OF FERTILIZED AND UNINCUBATED CHICKEN EGGS

Chromatln prepared both from the yolk granules beneath the blastoderm and from the nuclei of the blastoderm cells of fertilized and unincubated chicken eggs was examined under electron microscope and its structure was compared. The results indicate that the above two kinds of chromatin fibers seem to have no apparent difference in structural relation and diameter. The electron microscopic appearances of the basic structures of both kinds of chromatin are all "beads-on-a-string"-shaped filaments.After the digestion of chromatin from both raw materials with DNase Ⅰ, the connecting strings of chromatin fibers were cut off, only the scattered beads could be observed under electron microscope. The diameter of the scattered beads is equal to that of the beads on the chromatin fibers, and most of them are 150 in diameter.     

鸡和鹌鹑神经视网膜的发育年龄对其细胞聚集能力组织发生与生物化学分化的影响

本文以鸡胚和鹌鹑胚视网膜细胞所形成的细胞聚集团,观察其组织发生和谷氨酰胺合成酶的诱导作用。实验结果表明谷氨酰胺合成酶活力随发育年龄增加到第九天达到高峰,以后逐渐下降。在以鸡胚和鹌鹑胚视网膜细胞组成的混合细胞聚集团中,其酶活力均比预期值低;在9天鸡胚和7(1/2)天鹌鹑胚视网膜细胞的混合细胞聚集团中,有三种类型玫瑰花环,而9天与13天鹌鹑胚视网膜细胞的混合细胞聚集团中,仅有一种类型玫瑰花环。     

EFFECT OF EMBRYONIC AGE ON'AGGREGABILITY, HISTOGENESIS AND BIOCHEMICAL DIFFERENTIATION IN THE EMBRYONIC CHICK AND QUAIL NEURAL RETINA

In this paper, the different ages of the chicken and quail embryonic retina cell aggre-gates are used to examine the aggregation, histogenesis, and the induction of glutamine syn-thetase (GS) elicited by hydrocortisone. The results show that the GS inducibility in theretina cells increases at a slow rate, then rises sharply on the 9th day, and after 9 days,the GS inducibility of aggregates decreases with the increase of embryonic age. The observedvalue of induced GS activity in the chick retina cells coaggregate with quail embryonic retinacells is less than the expected value. Bispecific cell coaggregrates were observed when the9-day chicken embryonic retina cells and the 7(1/2)-day quail embryonic retina cells were com-bined and coaggregated, the chicken and quail cells formed three retinal rosettes. When the9-day chicken embryonic retina cells were commingled with the 13-day quail embryonic retinacells, in the coaggregates, only one retinal rosette was formed.     

鸡胚细胞核和胚下卵黄颗粒染色质的电子显微镜观察

本文从受精未孵育鸡蛋的胚下卵黄颗粒和胚细胞核,提取染色质进行电子显微镜观察,对其结构作了比较.实验结果表明,卵黄颗粒的染色质纤维与胚细胞核的染色质纤维,无论在形态结构和纤维粗细都无明显差别,其基本结构都呈串珠状. 两种材料提取的染色质,用DNase I消化后,在电子显微镜下只见散在的珠粒,纤维上珠粒间的DNA连丝被切断.珠粒的大小与染色质纤维上的珠粒大小相等,大多数为150埃;这些珠粒,由DNA连接成串珠状结构.     

TIME-LAPSE MICROCINEMATOGRAPHIC AND PHASE CONTRAST STUDIES ON THE CELL REFORMATION OF CHIROCEPHALUS YOLK GRANULES IN VITRO

In this article we report on a time-lapse microcinematographic and phase contrast study of the cell reformation of yolk granules which were isolated from mature oocytes in the genital sac of the middle female intersex of Chirocephalus nankinensis. The observations on yolk granules were made in fixed positions and the morphological changes of cell reformation were continuously recorded in vitro.The transformation of yolk granules into cellular structures may be tentatively described as follows: At the early stages in culture, it can be seen that the granular or bubbly structures gradually appear within the hyaloid and homogeneous yolk granules; the appearance of yolk granules gradually changes from elliptical into round shape. With further transformation, their appearances in general take the shape of oblate spheroids, their size is smaller than before and inside the yolk granules their granular and bubbly structures become more and more obvious. Finally, the nuclear and cellular structures can be seen i     

南京丰年虫卵黄颗粒在离体培养下重建为细胞的显微缩时电影和相差定位观察

本文就南京丰年虫(Chirocephalus nankinensis) 中雌中间性(middle female intersex)生殖囊内长成卵母细胞的卵黄颗粒,在离体培养下,借助于显微缩时电影和相差定位观察,叙述了细胞重建(cell reformation)的形态变化。 由卵黄颗粒转变为细胞结构的过程,大致可叙述如下:培养早期,在透明、均匀的卵黄颗粒中,逐渐出现颗粒状或小泡状结构,卵黄颗粒外形由椭圆形逐渐变圆;在进一步转变中,外形一般已成为扁圆形,体积较前变小,内部颗粒状和泡状结构更为显著,接着可见核结构和细胞结构。通过显微缩时电影和相差定位观察,连续地描述了从长成卵母细胞流出来的、外面带有卵母细胞胞浆(细胞质)的单个卵黄颗粒,在离体培养下,通过自组织、自装配(自组装),可以一步一步地建成细胞结构。现在,已经可以大批地培养出这种细胞结构,而且进行了多次的重复。这样,就能真实地反映了细胞重建;从形态变化看,它是客观存在的现象。