β-内酰胺酶基因在谷氨酸产生菌T_6-13染色体上的整合与表达

Expression and Integration of β-lactamase Geneinto the Genome of the Glutamic Acid-ProducingBacterium Strain T_6-13

以质粒pUC13编码的β-内酰胺酶基因为外源基因,通过随机连接谷氨酸产生菌T_6-13染色体DNA片段后转化T_6-13原生质体,使其整合到染色体上,得以表达.在实验条件下,所测19株转化子的抗性都有很高的稳定性,其中10株能百分之百地保持抗性.经生物素标记的pUC13为探针的分子杂交实验证实抗性基因已整合到T_6-13菌染色体DNA上。

The glutamic acid-producing bacterium strain T6-13 widly used in the industrial production of glutamin acid was transformed by β-lactamase gene in pUC 13 EcoR I fragment ligated at random to the EcoR I fragments of the host genome. Expression and integration of the resistance marker into the host genome led to some stable Apr transfor-mants. Under the experimental conditions, 10 of the total 19 isolated transformants were completely stable. Dot blots using biotin-labled probe pUC 13 and electrophoretic analysis of the total DNA of 4 transformants show that the β-lactamase gene is located in the genomic DNA of the glutamic acid-producing bacterium strain T6-13.