Janion C
Mol Gen Genet. 1977 Jun 8;153(2):179-83. doi: 10.1007/BF00264733.
It is known that cdd- S. typhimurium mutants selected for resistance to 5-fluorodeoxycytidine (FdCyd) possess no deoxycytidine kinase activity. The present study postulates that this method of screening selects double mutants defective in cytidine deaminase and in deoxycytidine kinase. To prove this hypothesis, the cdd mutant of S. typhimurium was constructed by P1-mediated transfer of ccd- gene into a new genetic background, and the activity of deoxycytidine kinase was assayed. Transductants exhibited no deoxycytidine kinase activity, showing that the absence of this enzyme is not limited to a specific cdd- mutant, but includes all strains of S. typhimurium. The toxicity of FdCyd for the bacterial strains possessing deoxycytidine kinase, as well as the role of nucleoside phosphorylase in nucleotide formation by S. typhimurium, is discussed.
已知为获得对5-氟脱氧胞苷（FdCyd）的抗性而筛选出的鼠伤寒沙门氏菌cdd突变体不具有脱氧胞苷激酶活性。本研究推测，这种筛选方法选择的是胞苷脱氨酶和脱氧胞苷激酶均有缺陷的双突变体。为了验证这一假设，通过P1介导将ccd -基因转移到新的遗传背景中构建了鼠伤寒沙门氏菌的cdd突变体，并测定了脱氧胞苷激酶的活性。转导子没有显示出脱氧胞苷激酶活性，表明这种酶的缺失并不局限于特定的cdd -突变体，而是包括所有鼠伤寒沙门氏菌菌株。文中还讨论了FdCyd对具有脱氧胞苷激酶的细菌菌株的毒性，以及核苷磷酸化酶在鼠伤寒沙门氏菌核苷酸形成中的作用。
