5-氟脱氧尿核甙(FUDR)是哺乳动物DNA 合成中一个有力的和特异性的抑制剂。作者在1976年已发现 FUDR 亦抑制弓浆虫生长,对 DNA 和 RNA 都有影响,而其一突变型(FUDR~R-1) 较野生型抗 FUDR 大一百倍,并曾推测其抗 FUDR 机制与哺乳动物同。本文通过实验证明了突变型弓浆虫抗FUDR 的机理与哺乳动物不同。 5-fluorodeoxyuridine (FUDR) is a potent and specific inhibitor of mammalian DNA synthesis. In 1976, the authors discovered that FUDR also inhibited the growth of Toxoplasma gondii and had an impact on both DNA and RNA, while its one mutant (FUDR~R-1) was 100 times more potent than wild-type anti-FUDR, and it had been speculated that it was resistant to FUDR. The mechanism is the same as that of mammals. This experiment demonstrated that the mechanism of mutant Toxoplasma gondii anti-FUDR is different from that of mammals.