短小芽孢杆菌作为芽孢杆菌属基因工程受体菌的研究

以质粒pUB110 DNA转化B. pumilus 289原生质体,转化频率为10~(-3)—10~(-9)与B.tubtilis 168系统相当;但B.pumilus 289原生质体的再生频率(0.3—12.0％)略低于B.subtilis 168(1.53—24.16％);在无选择压力条件下质粒pUB110在B.pumilus 289中经过45个世代周期,自发丢失率小于3％,同于B.subtilis 168系统。外源基因在B.pumilus 289中经25个世代周期丢失率低于5％,而在B.subtilis 168系统中则高达24％;外源基因的表达水平亦高于B.subtilis 168系统。因此,B.pumilus 289是一个值得进一步开发的基因工程受体系统。

Study on Bacillus pumilus as a Recipient Strain for Genetic Engineering of Bacillus

Bacillus pumilus 289 can be transformed easily by plasmid pUB110 through protoplast transformation with the frequency of 10-5-10-3 similar to B.subtilis AS 1.1176,a derivative strain of B.subtilis 168.The regeneration frequency of its protoplast is only slightly lower than B.subtilis AS1.1176 (0.3-12.0% compare to 1.53-24.16%).Plasmid pUB110 can be maintained in both bacterial strains stably.The frequency of loss of the plasmid in both strains is lower than 3% after 45 generations in LB medium.But it is quite different that the hybrid plasmid (pUB110 with 3.9 kb foreign DNA fragment) can be maintained much more stably in B.pumilus 289 than in B.subtilis AS1.1176.The frequency of loss of the plasmid is lower than 5% in B.pumitus 289 and 24% in B.subtilis AS1.1176 after 25 generations when they grown in SH medium.The expression level of foreign gene in B.pumilus 289 is also much higher than that in B.subtilis AS1.1176.Therefore B.pumilus 289 is valuable to be exploited as recipient strain for genetic engineering of Bacillus in the future.