The effect of a potent antitumor antibiotic, kazusamycin B, on the cell cycle of L1210 cells was examined. Kazusamycin B arrested synchronized L1210 cells at G1 phase. Retardation of metaphase initiation was also observed. Flow cytometric analysis of kazusamycin B-treated asynchronized cells also confirmed G1 arresting effect of kazusamycin B. In addition, an unidentified cell population with lower fluorescence intensity than G1 population was observed when the cells were exposed to the drug longer than 12 hours. Morphology of kazusamycin B-treated L1210 cells revealed that the intranuclear structure changed within 4 hours, and that abnormal condensation of nuclei coincided with the appearance of unidentified population. Kazusamycin B inhibited RNA synthesis moderately but specifically at 2 hours. However, this inhibition might be a secondary effect of the antibiotic-induced structural abnormality of the nuclei.

中文翻译：

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卡萨霉素B对培养的L1210细胞的细胞周期和形态的影响。

检查了有效的抗肿瘤抗生素卡祖霉素B对L1210细胞的细胞周期的影响。Kazusamycin B将同步化的L1210细胞阻滞在G1期。还观察到中期开始的迟缓。卡祖霉素B处理的异步细胞的流式细胞术分析也证实了卡祖霉素B的G1阻滞作用。此外，当细胞暴露于药物超过12小时时，观察到荧光强度低于G1群体的未鉴定的细胞群体。经卡祖霉素B处理的L1210细胞的形态学表明，核内结构在4小时内发生了变化，并且核的异常凝缩与身份不明的群体的出现相吻合。Kazusamycin B适度但在2小时内抑制RNA合成。然而，