Nano F E, Kaplan S
J Bacteriol. 1984 Jun;158(3):1094-103. doi: 10.1128/jb.158.3.1094-1103.1984.
Mu d1(Ap lac) was introduced into the photosynthetic bacterium Rhodopseudomonas sphaeroides 2.4.1. via the R-plasmid R751 in an attempt to isolate fusion derivatives involving photosynthetic operons. The selection system is potentially very powerful since R. sphaeroides is normally Lac negative. Among the exconjugants, photosynthesis-deficient mutants were recovered, some of which had elevated beta-galactosidase levels. Among the mutants examined, beta-galactosidase expression was linked exclusively to R751 . Many of the photosynthesis-deficient mutants were found to have alterations in their indigenous plasmids which apparently involved the exchange of DNA from one plasmid to another. Southern blot analysis revealed that there are extensive DNA sequences which are shared by the two plasmids that are involved in the rearrangements and that no exogenous DNA sequences appear to be involved. It was further discovered that plasmid rearrangement is a general phenomenon which can occur spontaneously in R. sphaeroides 2.4.1 and shows a high correlation with a photosynthesis minus phenotype.
通过R质粒R751将Mu d1(Ap lac)导入光合细菌球形红假单胞菌2.4.1中，试图分离涉及光合操纵子的融合衍生物。由于球形红假单胞菌通常为乳糖阴性，该选择系统可能非常强大。在接合后体中，获得了光合作用缺陷型突变体，其中一些突变体的β-半乳糖苷酶水平升高。在所检测的突变体中，β-半乳糖苷酶的表达仅与R751相关。发现许多光合作用缺陷型突变体的内源质粒发生了改变，这显然涉及到DNA从一个质粒交换到另一个质粒。Southern印迹分析表明，参与重排的两个质粒有广泛的DNA序列共享，且似乎没有外源DNA序列参与。进一步发现，质粒重排是一种普遍现象，可在球形红假单胞菌2.4.1中自发发生，并且与光合作用阴性表型高度相关。
