Effects on growth of <i>E. coli</i> after exposure to x-rays and treatment with penicillin: model for screening radiation chemical modifers in radiation oncology

Abstract

Cells of E.coli B/r were x-irradiated (330Gy) in the presence of oxygen and immediately incubated in a non-lethal concentration of penicillin (10u/ml).This caused enhanced growth of the cell into filaments which later disintegrated (ghosts) and failed to form colonies. Irradiation (950Gy) of these cells under anoxic conditions and incubation in penicillin did not cause enhanced killing or growth into filaments of the cells. These observations suggest that the combined action of x-irradiation followed by incubation in penicillin caused more cells to grow into nonviable filaments. The model has been successfully used to screen new hypoxic cell radiosensitizers and radioprotectectors by comparing their radiosensitization properties. Similar application of the method to test the efficacy of other drugs including natural herbs in our environment as radiation modifiers in radiation oncology is in progress.

Keywords: E.coli, filaments

West African Journal of Radiology Vol. 13(1) 2006: 41-46