庆大霉素适应性菌株遗传稳定性研究

适应性进化是工业微生物遗传育种的重要技术手段之一。以庆大霉素连续进化1 200代的干酪乳杆菌Zhang为研究对象,将其在去掉选择压力的培养基中连续传1 000代,对其细胞形态、活菌数、浊度、耐药表型、基因型的变化进行跟踪监测。研究结果显示:适应性菌株在去掉选择压力环境中进化1 000代后,其细胞形态、活菌数、浊度及耐药表型趋于稳定;基因组仅检测到11个突变位点,包括4个同义突变位点和7个非同义突变位点。干酪乳杆菌Zhang庆大霉素适应性菌株具有良好的遗传稳定性。

Studies on Genetic Stability of Gentamicin-adapting Strains

Adaptive laboratory evolution is an effective method to industrial microbial genetic breeding. In this study,Lactobacillus casei Zhang which was evolved in LSM medium with gentamicin to 1 200 generations, was used as the research object, continue to evolve in LSM medium without gentamicin to 1 000 generations. The change of cell morphology, viable count, turbidity, resistance phenotypic and genotype were tracked and monitored. The results showed that:①the cell morphology, viable count and turbidity and resistance phenotypic were stable;② Only 11 mutations were detected in the genome, including 4 synonymous mutations and 7 non-synonymous mutations. Therefore, it can be considered that the strain has a good genetic stability.