Hooper D C, Wolfson J S, McHugh G L, Swartz M D, Tung C, Swartz M N
Antimicrob Agents Chemother. 1984 May;25(5):586-90. doi: 10.1128/AAC.25.5.586.
The ability of novobiocin to eliminate (cure) the wild-type plasmid pMG110 from Escherichia coli has been compared with that of other inhibitors of the gyrase B subunit and of the gyrase A subunit. Novobiocin eliminated pMG110 , producing over 99% plasmid loss at concentrations two- to eightfold below the MIC for bacterial growth. Structurally related compounds ( clorobiocin , coumermycin A1, isobutyryl novenamine , and decarbamyl novobiocin) varied in their ability to eliminate pMG110 . Higher concentrations of drugs were required to eliminate pMG110 from a gyrB( Cour ) strain, implicating DNA gyrase in the curing phenomenon. For these drugs, the ratio of the concentration effecting maximal plasmid elimination to the MIC varied from 0.16 to 1.1, indicating that curing cannot be explained simply by inhibition of a pool of DNA gyrase equally available for replication of the bacterial chromosome and the plasmid DNA molecule. Inhibitors of the gyrase A subunit, nalidixic acid and oxolinic acid, eliminated pMG110 only to variable low levels. The differences in the ability of the gyrase A and B subunit antagonists to eliminate plasmids are discussed.
已将新生霉素从大肠杆菌中消除（治愈）野生型质粒pMG110的能力与其他回旋酶B亚基和回旋酶A亚基抑制剂的能力进行了比较。新生霉素消除了pMG110，在浓度比细菌生长的最低抑菌浓度（MIC）低两到八倍时，导致超过99%的质粒丢失。结构相关化合物（氯新生霉素、香豆霉素A1、异丁酰新生胺和脱氨甲酰新生霉素）消除pMG110的能力各不相同。从gyrB（Cour）菌株中消除pMG110需要更高浓度的药物，这表明DNA回旋酶与治愈现象有关。对于这些药物，实现最大质粒消除的浓度与MIC的比值在0.16至1.1之间变化，这表明治愈现象不能简单地通过抑制一组对细菌染色体和质粒DNA分子复制同样可用的DNA回旋酶来解释。回旋酶A亚基抑制剂萘啶酸和恶喹酸仅能将pMG110消除到不同的低水平。讨论了回旋酶A和B亚基拮抗剂消除质粒能力的差异。
