Abstract
A calorimetric analysis was made to characterize quantitatively the action of ethanol on the growth activity of yeast cells at 30°C. By using the multiplex calorimeter previously desinged, the growth thermograms of the yeast grown in liquid media containing ethanol at different concentrations were observed and the inhibitory effect of ethanol on the growth was analyzed in terms of the effect on specific growth activities as evaluated from (1) the change in growth rate constant and (2) the extent in retardation of growth. The ethanol concentration at which the specific growth activity is repressed by 50%, Ki, the index term to express the cooperativity of ethanol action, m, and the minimum inhibition concentration, MIC, determined from the two different view points were found to be in good agreement. From the result obtained it was concluded that the theoretical background employed for the analysis is a reasonable one and that the method of analysis developed here is useful for the quantitative study of the interactions between drugs and microbial cells.
