Evidence for an Electrostatic Field on Penicillin Assay Plates

Abstract

ONE of the effects of penicillin on susceptible bacteria is to cause a change in electrostatic charge which may be measured in terms of potentials, and which it has been suggested may be used quantitatively for assaying solutions of penicillin^1,2,3. So early as 1938, Loiseleur⁴ studied changes that occur in electrostatic charge during proteolysis, such as would be expected during lysis of bacterial cells. Similar changes in charge resulting in development of an electrostatic field can be shown on penicillin assay plates by treatment with electronegative or electropositive colloids suspended in buffers at pH. levels above or below the isoelectric range of the nucleoproteins.