Schwab H, Saurugger P N, Lafferty R M
Arch Microbiol. 1983 Nov;136(2):140-6. doi: 10.1007/BF00404789.
The broad host-range IncP-1 plasmids RP4 and RK2 were transferred by conjugation from Escherichia coli to Alcaligenes eutrophus H16. Among the transconjugants selected on media containing tetracycline, a considerable number did not express kanamycin resistance. By comparing restriction patterns of plasmids isolated from a large number of transconjugants a variety of different deletion derivatives were found. All of these possess more or less extended deletions always including parts of the tra 1-region. The plasmids RP4 and RK2, once established in A. eutrophus H16 showed a high stability and it can be concluded that deletion formation is connected with the conjugation process. Evidence is given that degradation of DNA entering an A. eutrophus recipient cell during the conjugative transfer process may be involved in deletion formation. Furthermore, the finding of a small deletion derivative of RP4 lacking the transacting replication function trfB and the entire kil-kor-system may allow the assumption that these gene functions are not essential for replication and maintenance of RP4 in A. eutrophus hosts.
广宿主范围的IncP-1质粒RP4和RK2通过接合作用从大肠杆菌转移至嗜碱假单胞菌H16。在含四环素培养基上筛选出的转接合子中,相当数量的菌株不表达卡那霉素抗性。通过比较从大量转接合子中分离出的质粒的限制性图谱,发现了多种不同的缺失衍生物。所有这些衍生物都或多或少存在延伸缺失,且总是包括tra 1区域的部分片段。质粒RP4和RK2一旦在嗜碱假单胞菌H16中稳定存在,就表现出很高的稳定性,由此可以得出结论,缺失的形成与接合过程有关。有证据表明,在接合转移过程中进入嗜碱假单胞菌受体细胞的DNA降解可能与缺失形成有关。此外,发现了RP4的一个小缺失衍生物,它缺乏反式作用复制功能trfB和整个kil-kor系统,这可能使人们假设这些基因功能对于RP4在嗜碱假单胞菌宿主中的复制和维持并非必不可少。