Stewart C R
J Bacteriol. 1969 Jun;98(3):1239-47. doi: 10.1128/jb.98.3.1239-1247.1969.
In a Bacillus subtilis deoxyribonucleic acid (DNA) preparation, extracted and purified by the Marmur procedure, the DNA molecules carrying a particular marker are heterogeneous with respect to molecular weight, buoyant density, and thermal stability. This finding constitutes evidence against unique points of breakage during DNA isolation. The variation in buoyant density suggests a local compositional heterogeneity in the chromosomal region of certain markers. The variation in molecular weight provides an explanation for the results of certain transformation experiments that are otherwise poorly understood. An example of such a result is the observation that acridine orange increases the efficiency of differential thermal inactivation of markers. An explanation of this phenomenon is suggested by the demonstration that acridine orange can decrease the natural intramarker heterogeneity in melting behavior.
在通过Marmur方法提取和纯化的枯草芽孢杆菌脱氧核糖核酸(DNA)制剂中,携带特定标记的DNA分子在分子量、浮力密度和热稳定性方面具有异质性。这一发现构成了反对DNA分离过程中独特断裂点的证据。浮力密度的变化表明某些标记的染色体区域存在局部组成异质性。分子量的变化为某些难以理解的转化实验结果提供了解释。这种结果的一个例子是观察到吖啶橙提高了标记物差异热失活的效率。吖啶橙可以降低天然标记物内部熔解行为的异质性,这一证明为此现象提供了解释。