Painter R B, Ginoza H S
Biophys J. 1966 Mar;6(2):153-62. doi: 10.1016/S0006-3495(66)86647-X.
The resistance transfer factor (RTF) episome was studied by measuring its inactivation by Co(60) gamma radiation, by incorporated P(32), and by tritium incorporated as tritium-labeled thymine. The D(37) for Co(60) irradiation was 7 to 9 x 10(4) rad. Growth of the bacteria harboring the RTF in BUdR (bromouracil deoxyriboside) increased the sensitivity of the RTF to the gamma radiation. The RTF was markedly inactivated by tritium after growth of the host (thymine requiring) bacteria in tritium-labeled thymine, thus further establishing the presence of thymine in the genome of the RTF. Assuming the efficiency of inactivation by P(32) to be 10%, the phosphorus content of the RTF was estimated to be about 2 x 10(5) P atoms/episome. The data suggest the RTF contains double stranded DNA with a molecular weight of the order of 3 to 8 x 10(7).
通过测量其被钴60γ射线、掺入的磷32以及作为氚标记胸腺嘧啶掺入的氚的灭活情况，对耐药传递因子（RTF）附加体进行了研究。钴60照射的D(37)为7至9×10⁴拉德。携带RTF的细菌在溴脱氧尿苷（BUdR）中生长会增加RTF对γ射线的敏感性。在宿主（需要胸腺嘧啶的）细菌在氚标记的胸腺嘧啶中生长后，RTF被氚显著灭活，从而进一步证实了RTF基因组中存在胸腺嘧啶。假设磷32的灭活效率为10%，估计RTF的磷含量约为2×10⁵个磷原子/附加体。数据表明RTF包含双链DNA，分子量约为3至8×10⁷。
