Pr^(3+)或La^(3+)与克拉红霉素对大肠杆菌的协同作用

Thermochemical Studies of the Synergism of Pr^(3+) or La^(3+) and Clarithromycin on Escherichia coli Growth Metabolism

用LKB-2277生物活性检测系统采用停流法于37℃测定了克拉红霉素及克拉红霉素分别与Pr(NO3)3和La(NO3)3混合后,对大肠杆菌生长抑制作用的热效应变化.根据热动力学模型进行了定量解析,得到了各体系的克拉红霉素浓度c与大肠杆菌生长速率常数k之间关系式及其半抑制浓度Ic50.克拉红霉素:k=0.03106-1.273×10-3cIc50=8.81μg·mL-1(0.5～20μg·mL-1)克拉红霉素+Pr3+:k=0.02967-1.332×10-3cIc50=7.38μg·mL-1(1～15μg·mL-1)克拉红霉素+La3+:k=0.02741-1.194×10-3cIc50=6.34μg·mL-1(1～15μg·mL-1)微量热结果不仅表征了克拉红霉素的抗菌活性强于红霉素,Pr3+或La3+与克拉红霉素协同作用也使抗菌活性增强,而且反映了不同药物作用下细菌的生理、生化和代谢过程热动力学特征的变化.

Using 2277 bioactivity monitoring system, we determined the changes of heat effect of inhibition of Clarithromycin with Pr(NO3)(3) or La(NO3)(3) on Escherichia coli growth at 37degreesC. According to the thermokinetic model, the relationship between the concentration of antibiotics ( c) and growth rate constant (k) and its half inhibitory concentration, Ic(50), were analyzed quantitatively. Clarithromycin: k = 0.03106-1.273 x 10(-3) c Ic(50) = 8.81 mug . mL(-1) (0.5similar to20 mug . mL(-1)) Clarithromycin + Pr3+: k = 0.02967-1.332 x 10(-3) c Ic(50) = 7.38 mug . mL(-1) (1similar to15 mug . mL(-1)) Clarithromycin + La3+: k = 0.02741-1.194 x 10(-3) c Ic(50) = 6. 34 mug . mL(-1) (1similar to15 mug . mL(-1)) The results of microcalorimetry experiments not only indicated that antibacterial activity of Clarithromycin was stronger than that of erythromycin, but also the changeable features of thermokinetics of the bacterial cell in biological, biochemical and metabolic process under the action of different drugs.