Wilcox K W, Smith H O
J Bacteriol. 1975 May;122(2):443-53. doi: 10.1128/jb.122.2.443-453.1975.
By a direct assay approach, mutants of Haemophilus influenzae Rd that are deficient in adenosine 5'-triphosphate-dependent deoxyribonuclease activity (add-) were isolated and characterized. A large proportion (50 to 90%) of the cells in cultures of these mutants failed to produce visible colonies when plated. An extensive analysis of the recombination proficiency of these strains revealed that the transformation frequency (transformants per competent cell) in the mutants was similar to that found in the wild type, but that the transformation efficiency (transformants per microgram of irreversibly bound deoxyribonucleic acid [DNA]) was reduced approximately fourfold. Sensitivities of the mutants to gamma rays, ultraviolet radiation, and methyl methane sulfonate were only slightly greater than wild-type levels. The rate of degradation of host DNA after ultraviolet irradiation was significantly reduced in the mutants. It is suggested that the adenosine 5'-triphosphate-dependent deoxyribonuclease in H. influenzae plays a nonessential role in DNA recombination and repair.
通过直接测定法，分离并鉴定了流感嗜血杆菌Rd中缺乏三磷酸腺苷依赖性脱氧核糖核酸酶活性（add-）的突变体。这些突变体培养物中很大一部分（50%至90%）的细胞在平板接种时无法产生可见菌落。对这些菌株的重组能力进行的广泛分析表明，突变体中的转化频率（每个感受态细胞的转化子数）与野生型相似，但转化效率（每微克不可逆结合的脱氧核糖核酸[DNA]的转化子数）降低了约四倍。突变体对γ射线、紫外线辐射和甲基磺酸甲酯的敏感性仅略高于野生型水平。突变体中紫外线照射后宿主DNA的降解速率显著降低。有人提出，流感嗜血杆菌中的三磷酸腺苷依赖性脱氧核糖核酸酶在DNA重组和修复中起非必需作用。
