Heberlein G T, Lippincott J A
J Bacteriol. 1967 Nov;94(5):1470-4. doi: 10.1128/jb.94.5.1470-1474.1967.
The ability of Agrobacterium tumefaciens to induce pinto leaf tumors may be enhanced two- to threefold after treatment with mitomycin C. The enhancement may be obtained with either lethal or nonlethal concentrations. With 10-min treatments, an optimal response was obtained with 0.005 mug of mitomycin C per ml in the absence of any change in the number of viable cells. Both the tumor induction process and the tumors induced by treated cultures appear qualitatively the same as controls. To account for these results, the antibiotic must increase the proportion of viable cells that will subsequently initiate tumors. One, or at most a few, random lesions in the bacterial chromosome seem to be the necessary requirement for this promotion. At mitomycin concentrations of 1 and 5 mug/ml, the ability of A. tumefaciens to initiate tumors is rapidly lost, indicating that a fairly intact bacterial chromosome is one of the essentials for the tumor induction process.
用丝裂霉素C处理后，根癌土壤杆菌诱导菜豆叶肿瘤的能力可能会增强两到三倍。无论使用致死浓度还是非致死浓度均可获得这种增强效果。处理10分钟时，在每毫升含0.005微克丝裂霉素C的情况下可获得最佳反应，此时活细胞数量没有任何变化。处理后的培养物诱导肿瘤的过程以及所诱导的肿瘤在性质上与对照似乎相同。为了解释这些结果，抗生素必须增加随后会引发肿瘤的活细胞比例。细菌染色体中一个或至多几个随机损伤似乎是这种促进作用的必要条件。在丝裂霉素浓度为1微克/毫升和5微克/毫升时，根癌土壤杆菌引发肿瘤的能力迅速丧失，这表明相当完整的细菌染色体是肿瘤诱导过程的要素之一。
