Response of to heavy element stress; Lead vs. uranium

Sakamoto, Fuminori  ; Onuki, Toshihiko; Fujii, Tsutomu*; Iefuji, Haruyuki*

We have examined the responses of in media containing Pb ions and compared it to those in media containing UO ions to elucidate the stress effects of heavy elements. Cultivation of in a medium containing 1.010 M Pb showed nearly the same growth as that in the control medium while growth was inhibited in the medium containing 1.010 M Pb. Backscattering electron image analyses of thin sections of cells showed that Pb had accumulated inside the cells. Two-dimensional (2D) gel electrophoresis analysis of the proteins extracted from the exposed to Pb ions showed that several specific protein spots were expressed after cultivation with Pb, that did not appear in the control medium. Our results suggest that Pb more weakly inhibits the growth of than UO, and produces different stresses in than UO.