Abstract
Addition of Mn(II) at 2.5 uM or higher to stationary-phase cultures of Deinococcus radiodurans strain IR was found to trigger at least three roundsof cell division. This Mn(II)-induced cell division (Mn-CD) did not occurwhen the culture was in the exponential or death phase. The Mn-CD effectproduced daughter cells proportionally reduced in size, pigmentation andradioresistance, but proportionally increased in activity and amount of the oxygen-toxicity-defensive enzymes, superoxide dismutase and catalase. Inaddition, the concentration of an Mn-CD induced protein was found to remain high throughoyt the entire Mn-CD phase. It was also found that an untreated culture exhibited a growth curve characterized by a very rapid exponential-stationary transition, and that cells which have just reached the early stationary phase were synchronous. Our results suggest the presence ofa Mn(II)-sensitive mechanism for controlling cell division. The Mn-CD effect appears to be specific to the cation Mn(II) and the radioresistant bacteria, deinococci.在抗輻射奇異球菌 (Deinococcus spp.) 的生長生理研究中, 我的實驗結果顯示某些金屬離子對這一屬細胞生長與分裂有極為特殊的影響. 此篇論文中詳述其效應, 並以生化測定及電子顯微切片探討可能之調控機轉.