研究了超声对大肠杆菌生长和重组蛋白表达的影响,采用分光光度法测定其生长速度、Tricine-SDSPAGE法检测重组蛋白的表达、Fura-2/AM荧光法测定大肠杆菌细胞的钙离子浓度。结果显示,利用频率为(28±2)kHz的超声波在接种后(时期1)对大肠杆菌处理30 min后能明显促进其生长,而此时超声处理5、30和60min对重组蛋白的表达均没有明显影响,在生长密度为OD600=1.0(时期2)时超声对菌株生长和蛋白表达都具有抑制作用;荧光法得到超声处理30 min使细胞内Ca2+浓度降低最多。该研究证实了超声能明显影响大肠杆菌的生长代谢,为今后利用超声波技术强化工程菌发酵方法的建立奠定了基础。

This study was aimed to investigate the effect of ultrasonic stimulation on the growth and protein expression of Escherichia coli( E. coli) at different periods. The growth was measured by spectrophotometric method and the protein expression was detected by Tricine-SDS-PAGE analysis. Fura-2 / AM fluorescence probe was used to determine the change in intracellular Ca2 +concentration. Results showed that the cells were stimulated by ultrasound at 28 ± 2 kHz for 30 min after inoculation( period 1),under which the growth was obviously promoted by ultrasonic stimulation over the control. The protein expression was not increased by the ultrasound agitation for 5,30,and 60 min at period 1. When the ultrasonic stimulation occurred at the time of optical density at 1. 00( period 2),the cell growth and protein expression were inhibited. Results showed that concentration of Ca2 +was decreased to the lowest point by ultrasonic treatment for 30 min. This research confirmed that ultrasound could affect the growth and metabolism of E. coli,which provided a basis for the use of ultrasound to enhance the fermentation of engineering bacteria.