Evaluation of biological effects of gamma-rays in Escherichia coli cells

Some biological effects of gamma-rays have been evaluated in cells of the bacteria Escherichia coli, through the comparison of the number of colonies formed by a unitary cell (CFU) proceeded from an unirradiated control suspension and from an irradiated suspension, and through the visualization of possible damage in the microorganism enzymatic system due to irradiation with high energy photons (/sup 60/Co /spl gamma/-rays). For this purpose, for absorbed doses at up to 280 Gy, the methods of successive dilutions and sowing in Petri plates containing simple agar and MacConkey agar, were used. It was verified that the irradiated suspension presented a growth of up to 10 times lesser than the growth of the suspension that had been controlled, but it was not possible to visualize damage in Escherichia coli enzymatic system, due to irradiation with the absorbed dose values tested.