Influence of Growth Phase on Radiation Stimulation of Proliferation in Synechococcus lividus in Culture

CONTER, A., DUPOUY, D., AND PLANEL, H. Influence of Growth Phase on Radiation Stimulation of Proliferation in Synechococcus lividus in Culture. Radiat Res. 99, 651-658 (1984). Previous results from this laboratory have shown that background radiations or exposure to very low doses of chronic y radiation can stimulate the proliferation of the blue-green algae Synechococcus lividus. To determine the factors controlling the cell response to these low doses, investigations were performed with cultures inoculated with cells selected from cultures in exponential, transient, and stationary phases and exposed to chronic irradiation at a dose rate of 20 mGy/year. Transient cells exhibit the greatest growth stimulation; exponential cells are the least radiosensitive. Stationary cells represent an intermediary stage. The modification in cell proliferation occurs only at the beginning of the experiment when inoculated cells have a reduced