Evolution with time of the zero-current potential of a gold electrode in Escherichia coli cultures supplied with lipoic acid: Part II. Properties of the model and their application to investigations on drug effects on bacterial activity

In agreement with the in vivo time-courses of the gold electrode zero-current potential, the computer-simulated potential-time curves could be conveniently described by simple geometric magnitudes. We have investigated the influence exerted by the theoretical parameters of the model on these magnitudes.The lag time necessary for the sudden shift of potential to appear at low (10⁻⁵M) initial concentration of exogenic LA was decreased by simulating an increase of the reductive activity of cultures. The slope of the potential-time curves at low and high (2×10⁻⁴M) LA initial concentration changed in opposition with the lag time.These properties have suggested comparative in vivo potential-time measurements in the presence of drugs affecting bacterial activity. From the experimental modifications of the potential-time curves, the theoretical parameter(s) affected by the drug could be identified and discussed in relation to known results of molecular and cellular biology.Some illustrative examples of such an application have been developed. The effect of insulin on the potential-time curves has been attributed to a hormonal action at the bacterial cell membrane level. Marked differences in the effects of two different antibiotics (ampicillin and lividomycin) on the time evolutions of potential have also been analyzed and discussed within the frame of the theory.     

541—Evolution with time of the zero-current potential of a gold electrode in escherichia coli cultures supplied with lipoic acid: Part II. Properties of the model and their application to investigations on drug effects on bacterial activity

In agreement with the in vivo time-courses of the gold electrode zero-current potential, the computer-simulated potential-time curves could be conveniently described by simple geometric magnitudes. We have investigated the influence exerted by the theoretical parameters of the model on these magnitudes.The lag time necessary for the sudden shift of potential to appear at low (10^?5M) initial concentration of exogenic LA was decreased by simulating an increase of the reductive activity of cultures. The slope of the potential-time curves at low and high (2 × 10^?4M) LA initial concentration changed in opposition with the lag time.These properties have suggested comparative in vivo potential-time measurements in the presence of drugs affecting bacterial activity. From the experimental modifications of the potential-time curves, the theoretical parameter(s) affected by the drug could be identified and discussed in relation to known results of molecular and cellular biology.Some illustrative examples of such an application have been developed. The effect of insulin on the potenlial-time curves has been attributed to a hormonal action at the bacterial cell membrane level. Marked differences in the effects of two different antibiotics (ampicillin and lividomycin) on the time evolutions of potential have also been analyzed and discussed within the frame of the theory.