Meier Patricia Stutzmann, Troller Rolf, Heiniger Nadja, Hays John P, van Belkum Alex, Aebi Christoph
Institute for Infectious Diseases, University of Bern, Bern, Switzerland.
FEMS Microbiol Lett. 2006 Sep;262(1):72-6. doi: 10.1111/j.1574-6968.2006.00365.x.
The human respiratory tract pathogen Moraxella catarrhalis is a naturally competent microorganism. However, electrotransformation has long been used to introduce foreign DNA into this organism. This study demonstrated that electrotransformants obtained with linear or circular nonreplicating plasmid DNA originated exclusively from natural transformation processes taking place during the recovery phase after the application of current. Only replicating plasmid DNA could be introduced into M. catarrhalis by electrotransformation, in a type IV pilus-independent manner. Electrotransformation with homologous genomic DNA indicated that restriction of double-stranded DNA was independent of type III restriction-methylation systems. Nontransformability of M. catarrhalis by electrotransformation was observed using double- as well as single-stranded DNA. In addition, the study showed that natural competence is a very constant feature of M. catarrhalis.
人类呼吸道病原体卡他莫拉菌是一种天然感受态微生物。然而，电转化长期以来一直被用于将外源DNA导入该生物体。本研究表明，用线性或环状非复制性质粒DNA获得的电转化体完全源自施加电流后恢复阶段发生的自然转化过程。只有复制性质粒DNA可以通过电转化以不依赖IV型菌毛的方式导入卡他莫拉菌。用同源基因组DNA进行电转化表明，双链DNA的限制与III型限制-甲基化系统无关。使用双链和单链DNA均观察到卡他莫拉菌不能通过电转化进行转化。此外，该研究表明天然感受态是卡他莫拉菌非常稳定的特征。
