Cytological aspects of antimicrobial antibiosis. I. Cytological changes associated with the exposure of Escherichia coli to colistin sulfate.

Chapman, George B. (Cornell University Medical College, New York, N.Y.). Cytological aspects of antimicrobial antibiosis. I. Cytological changes associated with the exposure of Escherichia coli to colistin sulfate. J. Bacteriol. 84:169-179. 1962-Broth cultures of Escherichia coli were exposed to different concentrations of the antibiotic colistin sulfate for various lengths of time. Control (untreated) and treated cells were fixed, dehydrated, and embedded in methacrylate or Epon. Ultrathin sections were examined in an RCA EMU2-D electron microscope. Two conspicuous cytological changes were noted. First, the nuclear material disappeared from its normal sites and was no longer demonstrable. Second, the cytoplasm lost its granularity and became homogeneous. Cells which showed these changes were nonviable.