de Campos Vidal B
Department of Cell Biology, Institute of Biology, State University of Campinas (Unicamp), Campinas, SP, 13083-970, Brazil.
Cell Biol Int. 2000;24(10):723-8. doi: 10.1006/cbir.2000.0555.
The present study was undertaken to test the reproducible formation of the extended chromatin fibres (ECF), beads and superbeads, and detect molecular order and crystallinity by optical anisotropies in those structures. Chicken erythrocyte smears and mouse liver cell imprints were treated with 2.0-3.0 m NaCl solution in 1% Triton-X100 vertically prior to staining with 0.025% toluidine blue at pH 4. Detection of birefringence and colours of abnormal dispersion of birefringence (ADB) following toluidine blue binding to DNA revealed that the DNA molecular order and crystallinity in decondensed and condensed chromatin are preserved after ECF formation. The tests for Con-A binding to mannose/glucose residues of glycoproteins was confirmed within nuclei, and in the ECF, beads and superbeads. ECF formation was not regular. Clumped cells did not show ECF, although chromatin mobility was observed within the nuclei. Electron microscopy demonstrated that after treatment of nuclei with 0.77 m NaCl ECF always spread from the nuclei, in clumped nuclei the fibres aggregated instead of spreading.
本研究旨在测试延伸染色质纤维（ECF）、珠状物和超级珠状物的可重复形成，并通过这些结构中的光学各向异性检测分子有序性和结晶度。在用0.025%甲苯胺蓝在pH 4条件下染色之前，先将鸡红细胞涂片和小鼠肝细胞印记垂直用含1% Triton-X100的2.0 - 3.0 m NaCl溶液处理。甲苯胺蓝与DNA结合后双折射和双折射异常色散（ADB）颜色的检测表明，在ECF形成后，去浓缩和浓缩染色质中的DNA分子有序性和结晶度得以保留。在细胞核内以及ECF、珠状物和超级珠状物中证实了Con-A与糖蛋白的甘露糖/葡萄糖残基的结合试验。ECF的形成并不规则。聚集的细胞未显示出ECF，尽管在细胞核内观察到了染色质的移动性。电子显微镜显示，用0.77 m NaCl处理细胞核后，ECF总是从细胞核中扩散出来，在聚集的细胞核中，纤维聚集而不是扩散。
