Barany F, Kahn M E
J Bacteriol. 1985 Jan;161(1):72-9. doi: 10.1128/jb.161.1.72-79.1985.
Transformation pathways in two closely related bacterial species, Haemophilus parainfluenzae and Haemophilus influenzae, were studied. Both organisms rapidly take up transforming DNA within minutes into specialized membranous structures on the cell surface (transformasomes). DNA within transformasomes is in a protected state, inaccessible to external DNase or internal restriction and modification enzymes. However, the subsequent processing of donor DNA differs in these two organisms. In H. influenzae, linear DNA immediately undergoes degradation from one end at a constant rate, leaving a lower-molecular-weight intermediate in the transformasome. The end undergoing degradation is searching for homologous regions of the chromosome. Once pairing is initiated, the remaining lower-molecular-weight DNA exits from the transformasome, and a single strand undergoes efficient integration. In contrast, in H. parainfluenzae little degradation of donor DNA is observed, with the majority remaining intact within the transformasomes after 1 h. Thus, whereas only 10% of donor DNA molecules leave the protected state after 1 h, portions of each molecule appear to become quantitatively integrated.
对两种密切相关的细菌——副流感嗜血杆菌和流感嗜血杆菌的转化途径进行了研究。这两种生物体在数分钟内就能迅速将转化DNA摄取到细胞表面的特殊膜结构（转化体）中。转化体内的DNA处于受保护状态，外部的DNase或内部的限制酶及修饰酶都无法作用于它。然而，这两种生物体中供体DNA的后续处理过程有所不同。在流感嗜血杆菌中，线性DNA立即从一端以恒定速率开始降解，在转化体中留下较低分子量的中间体。发生降解的一端会寻找染色体的同源区域。一旦配对开始，剩余的较低分子量DNA从转化体中排出，单链进行高效整合。相比之下，在副流感嗜血杆菌中，观察到供体DNA几乎没有降解，1小时后大部分仍完整地保留在转化体内。因此，虽然1小时后只有10%的供体DNA分子离开受保护状态，但每个分子的部分似乎会进行定量整合。
