Brenner D J, Cowie D B
J Bacteriol. 1968 Jun;95(6):2258-62. doi: 10.1128/jb.95.6.2258-2262.1968.
Single-stranded, labeled deoxyribonucleic acid (DNA) fragments from Escherichia coli were incubated at 60 and 66 C with a large excess of single-stranded, unlabeled DNA fragments from E. coli and Salmonella typhimurium. The resulting reassociated DNA was adsorbed to hydroxylapatite and eluted in a series of washes at increasing temperatures. The thermal stability of the reassociated DNA was determined by means of this procedure. Neither the extent of reassociation nor stability of the reassociated E. coli DNA was affected by increasing the incubation temperature from 60 to 66 C. The double-stranded molecules resulting from the reassociation of E. coli DNA with S. typhimurium DNA had a markedly lower thermal stability than reassociated E. coli DNA. More reassociation occurred between E. coli and S. typhimurium at 60 C than at 66 C. In addition, the product of interspecies reassociation occurring at 66 C had a higher thermal stability than that occurring at 60 C. Preliminary results indicate that the decreased thermal stability of the interspecies duplex is in part the result of unpaired bases.
将来自大肠杆菌的单链、标记的脱氧核糖核酸（DNA）片段与大量过量的来自大肠杆菌和鼠伤寒沙门氏菌的单链、未标记的DNA片段在60℃和66℃下孵育。将所得重新缔合的DNA吸附到羟基磷灰石上，并在一系列温度逐渐升高的洗涤中洗脱。通过该程序测定重新缔合的DNA的热稳定性。将孵育温度从60℃提高到66℃，既不影响大肠杆菌DNA重新缔合的程度，也不影响其稳定性。大肠杆菌DNA与鼠伤寒沙门氏菌DNA重新缔合产生的双链分子的热稳定性明显低于重新缔合的大肠杆菌DNA。在60℃时，大肠杆菌和鼠伤寒沙门氏菌之间发生的重新缔合比在66℃时更多。此外，在66℃发生的种间重新缔合产物的热稳定性高于在60℃发生的产物。初步结果表明，种间双链体热稳定性降低部分是未配对碱基的结果。
