Structure-Activity Relationships of Tetracyclines I: Inhibition of Cell Division and Protein and Nucleic Acid Syntheses in Escherichia coli W

Abstract

The kinetics of inhibition of Escherichia coli in a peptone broth as a function of the concentration of 18 tetracyclines were determined. Viable and total cell count methods were used to measure rates of cell division. Rates of protein and nucleic acid syntheses were determined simultaneously by a membrane filter technique in conjunction with the Folin-Lowry assay and the orcinol reaction, respectively. The relationship of these rate constants to antibiotic concentration is an accurate estimate of activity under the test conditions. Different times before onset of inhibition of protein synthesis, cell division, and nucleic; acid synthesis are observed in kinetic experiments. These differences are interpreted as being consistent with theories of primary inhibition of protein-synthesizing systems.