RESUMEN
Microorganisms are very sensitive to the effect of metal ions and a deficit or an excess of essential metal ions may induce some cell disturbances. The main objective of this research is to evaluate the effect of toxic metal ions. Doing that, the effects of metal ions on the electrophysical properties of the cell membrane, probed by electroorientational spectroscopic techniques and analysis of the electrophoretic mobility of cells have been chosen for investigation. The purpose of this work is to determine the optimal conditions of investigation of different kinds of microorganisms exposed to Cu. pH had a great influence on the electrophysical changes induced by Cu and this may be related to the speciation of the metal, according to its degree of hydroxylation. It will now be possible to compare the effects of toxic metal ions (Cd, Hg, Pb, etc..) or therapeutic metal ions (Pt, Ga, Ru, Ti, Sn, etc..) with those observed for Cu, in the conditions optimized by this study.