Microcalorimetric Evaluation of the Effect of Kanamycin: An Analysis Based on the Median-Effect Principle
Abstract
A study of the effect of drug, kanamycin, on the growth metabolism of recombinant Escherichia coli B1 was carried out by microcalorimeter monitoring of the metabolic activity of treated cells. Power-time curves of growing recombinant Escherichia coli cell suspensions, treated with different kanamycin doses, were recorded. The extent of the effect was evaluated by changes in the slopes of the microcalorimetric curves and the kinetics of the drug action was interpreted from the time at which these changes reached their maximum values and maintained their maximum values. Experimental dose-effect relationships conform to the median-effect principle of the mass-action law: fa/(1−fa)=(D/D50)m. A plot of y=lg[(fa)1−1]−1 versus x=lg D gives the slope m, D50 and R∞. The experimental results revealed that high concentration of kanamycin had an inhibitory effect on the growth of recombinant Escherichia coli B1 in the lg phase, and had a promoting effect in the stationary period. Moreover, it was demonstrated that microcalorimetry was a reliable method for the detection of modulatory effects in biology.
