Cadmium detoxification mechanism in Klebsiella aerogenes ATCC 10031.
1990
Lee K.S. | Yoo S.A. | Kwak I.Y. | Park Y.S. | Choi Y.K.
In order to examine what kind of system correlated with cadmium detoxification mechanism in Klebsiella aerogenes ATCC 10031, we tried to investigate the effect of phosphate upon the detoxification and also elucidate whether the cadmium phosphate and/ or polymeric Cd-Pi complex is formed actually in cell or not. As the results, it was shown that growing pattern had long lag adaptive phase of 12 hr to 24 hr, at the concentrations of 0.02 mM and 0.08 mM cadmium, respectively. Cadmium was accumulated more highly in the fraction of cel wall and membrane than in those of cytoplasm. In case of phosphate starving cells added cadmium, inorganic polyphosphate system was primarily correlated with Cd-detoxification during the lag phase for the accommodation to cadmium, on the other hand, Cd:Sulfide complex system secondarily correlated it during the stationary phase. These results implied that polyphosphate system and Cd:sulfide complex system, these two systems were operated compensatively each other. Considering the results observed with EM and examined the changes of sulfide and polyphosphate amount, it was reflected that Cd:S complex was located at the cell surface. In the results of in-vivo 31P NMR spectra in the cells with cadmium pressure, several phosphate signals arose newly from the polyphosphate region with moving chemical shift of it. This phenomenon strongly implied the actual existence of Cd:Pi complex and/ or Cd:poly-P complex in the cell and also the cellular compartmentalization of cadmium detoxifying mechanism.
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