White M T, Wagner E K, Tewari K K
Cancer Res. 1975 Apr;35(4):873-9.
Mitochondrial DNA's (mtDNA) isolated from rat liver and the Novikoff hepatoma grown as both solid tumors and cells in monolayer culture were examined by a variety of physicochemical techniques. Buoyant densities in analytical CsCl equilibrium gradients and thermal denaturation profiles revealed no significant differences in base composition among the mtDNA's isolated from liver, tumor, and hepatoma cells. Sedimentation in neurtral and alkaline CsCl showed no differences in mtDNA size. However, tumor and hepatoma cell mtDNA's were slightly smaller and more heterogeneous in size than liver mtDNA when molecular contour lengths were measured in the electron microscope. Based on chemical determinations, neoplastic mitochondria contained four to five times more DNA per mitochondrion than liver. Also, electron microscopy showed the proportion of mtDNA in complex forms (catenated dimers and oligomers) to be much higher in tumor (18%) and hepatoma cells (15%) than liver (4%).
运用多种物理化学技术，对从大鼠肝脏以及以实体瘤和单层培养细胞形式生长的诺维科夫肝癌中分离出的线粒体DNA（mtDNA）进行了检测。分析型氯化铯平衡梯度中的浮力密度和热变性图谱显示，从肝脏、肿瘤和肝癌细胞中分离出的mtDNA在碱基组成上无显著差异。在中性和碱性氯化铯中的沉降表明，mtDNA大小无差异。然而，当在电子显微镜下测量分子轮廓长度时，肿瘤和肝癌细胞的mtDNA比肝脏mtDNA略小且大小更不均一。基于化学测定，肿瘤线粒体每个线粒体所含的DNA比肝脏多四到五倍。此外，电子显微镜显示，肿瘤（18%）和肝癌细胞（15%）中以复杂形式（连环二聚体和寡聚体）存在的mtDNA比例比肝脏（4%）高得多。
