几种动物染色体超微结构的研究

应用表面舒展技术、原位培养表面舒展技术和临界点干燥以及空气干燥等方法制备染色体标本,用FESEM和SEM观察了CHO、IB-RS-2哺乳动物细胞以及黄鳝肾细胞和鲫鱼血淋巴细胞的染色体。看到了染色体处于不同舒展状态的染色质纤维。在染色质纤维未完全展开排列紧密时,染色体臂的染色质纤维,缠绕排列有序,垂直于染色体纵轴,螺旋盘绕形成疏密程度不同的横纹。在纤维较为松散和完全松敌的状态下,可以看见直径约为300(?)的染色质纤维从有序到不完全有序到无序,弯扭、螺旋、缠绕,有些似“辐射环”状结构。在着丝点处可清楚地看到有二条纤维平行分别通连二染色单体臂,未见有染色体膜。初步比较了鱼类和哺乳类的染色质纤维,二者基本一致,但鱼类染色质纤维排列较哺乳动物的松散,类似“辐射环”状的结构较为明显。

Studies on Chromosome Ultrastructure in Several Animal Species

The metaphase chromosomes prepared by surface spreading method and critical point drying and air drying method in CHO and IB-RS-2 cell lines and the lymphocytes of Caras-sius aurams and the kidney cells of Monopterus albus were observed with a scanning electron microscope.The chromosome bands were observed without treatment of G-banding.The stereographical examination of surface spread chromosomes revealed that stretched chromosomes were composed of a mass of twisted looping fibers with an average diameter of about 300 A.The centromere region was distinguishable in the mass of the chromatin fibers and two chro-matin fibers which pass through the centromere arranged paralle to the axis of the chromatid stretched i-nto chromosome arms.Chromosome membrane was not observed.Comparing fish chromosomes with mammalin chromosomes,the diameter of basic fiber is identical about 300 A The twist state of the fish chromatin fibers were looser than that of the mammalian.