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目的探讨不同因素对低频低强度超声(LFLIU)介导质粒转入大肠杆菌的效率影响。方法大肠杆菌和质粒DNA混合液用42kHz,0.13~0.72 W/cm~2超声辐照后,在氨苄霉素琼脂培养板上进行菌落计数,计算质粒转化效率。同时,检测不同强度超声对大肠杆菌存活率和质粒完整性的影响。结果 (1)大肠杆菌和质粒混合液经LFLIU辐照后,能成功在氨苄霉素琼脂培养板上筛选出携带抗性的菌株,质粒转化效率与超声辐照剂量和CaCl_2浓度有关。(2)流式细胞仪检测结果表明,0.13~0.72 W/cm~2的超声辐照对大肠杆菌的活力无显著影响。(3)电泳检测结果显示,不同强度超声辐照质粒,随着超声强度的增加,导致质粒构型改变,但不影响其结构的完整性。结论 LFLIU能够介导质粒转入大肠杆菌,可为LFLIU将质粒和基因转入其他特殊细菌提供实验参考。
Objective To investigate the effect of different factors on the efficiency of low-frequency, low-intensity ultrasound (LFLIU) -mediated plasmid transfer into Escherichia coli. Methods The colonies were counted on ampicillin agar plates after the mixture of Escherichia coli and plasmid DNA was irradiated by ultrasound at 42kHz and 0.13 ~ 0.72 W / cm ~ 2, and the plasmid transformation efficiency was calculated. At the same time, the effects of different intensities of ultrasound on the viability of Escherichia coli and plasmid integrity were tested. Results (1) After the mixture of E. coli and plasmid was irradiated by LFLIU, the resistant strains were successfully screened on the ampicillin agar plates. The plasmid transformation efficiency was related to the dose of ultrasound irradiation and the concentration of CaCl 2. (2) The results of flow cytometry showed that ultrasonic irradiation of 0.13 ~ 0.72 W / cm ~ 2 had no significant effect on the viability of E. coli. (3) The results of electrophoresis showed that the plasmids were irradiated with different intensities of ultrasound, which resulted in the change of the plasmid configuration with the increase of the intensity of ultrasound, but did not affect the structural integrity. Conclusion LFLIU can transfer plasmids into Escherichia coli and provide an experimental reference for LFLIU to transfer plasmids and genes into other special bacteria.