Filippovich I V, Sorokina N I, Soldatenkov V A, Romantzev E F
Int J Radiat Biol Relat Stud Phys Chem Med. 1982 Jul;42(1):31-44. doi: 10.1080/09553008214550891.
Mouse thymocyte fractions were isolated on the basis of buoyant density in a step-gradient of human serum albumin. These fractions were characterized by cell size, radiosensitivity and hydrocortisone sensitivity, and by labelled precursor incorporation into DNA, RNA and proteins. The relative sedimentation of nucleoids in sucrose gradient was also determined. Large and more radioresistant thymocytes were characterized by an increased rate of DNA repair compared with the fraction of radiosensitive small lymphocytes. Nucleoids prepared from the small thymocyte fraction had greater relative sedimentation rates than those derived from large cells. The response of relative sedimentation of nucleoids from large and small thymocyte fractions to ethidium bromide concentration does not permit a conclusion on different superhelix density for DNA in cells of these fractions. At the same time the estimate of the supercoiled domain size for nucleoids of large and small thymocyte fractions showed that in the more radiosensitive small cells domains of greater size were predominant.
小鼠胸腺细胞组分是根据其在人血清白蛋白阶梯梯度中的浮力密度分离得到的。这些组分通过细胞大小、放射敏感性和氢化可的松敏感性，以及标记前体掺入DNA、RNA和蛋白质的情况进行表征。还测定了核小体在蔗糖梯度中的相对沉降情况。与放射敏感的小淋巴细胞组分相比，大的且放射抗性更强的胸腺细胞的DNA修复速率更高。从小胸腺细胞组分制备的核小体的相对沉降速率比从大细胞制备的核小体更高。大、小胸腺细胞组分的核小体相对沉降对溴化乙锭浓度的反应无法得出关于这些组分细胞中DNA超螺旋密度不同的结论。同时，对大、小胸腺细胞组分核小体超螺旋结构域大小的估计表明，在放射敏感性更高的小细胞中，更大尺寸的结构域占主导。
