HIGH CAPACITY FOR COPPER CAPTURE BY AN Escherichia coli STRAIN DEFICIENT IN NADH DEHYDROGENASE-2

GRILLO PUERTAS, M; SCARAVAGLIO, OR; VOLENTINI, SI; RAPISARDA, VA; RODRÍGUEZ MONTELONGO, L

Rosario - Santa Fe

Congreso; SAIB; 2006

Sociedad Argetnina de Investigaciones Bioquimicas

We found that an Escherichia coli strain deficient in NADH dehydrogenase-2 presented a lower extracellular Cu(II)-reduction and a higher intracellular metal accumulation than the parental strain, after incubations with nontoxic copper concentrations. The aim of the present work was to further analyze that behavior when bacteria are incubated with high copper concentrations. Cells of the strains ANN001 (deficient in NDH-2) and AN387 (wild-type) were harvested in stationary phase and incubated with different copper concentrations, in the presence of a respiratory substrate. ANN001 had higher copper capture ability than its parental strain. The cellular viability decreased in both strains upon copper incubations, although the damage is higher in the mutant strain. These results were corroborated by measuring the oxygen consumption and by analyzing the activity of the respiratory chain components. In addition, the metal concentration in the solution significantly decreased, when it was incubated several times with fresh cells. Even though the results are preliminary, they suggest that bacterial strains deficient in respiratory chain components could be used to reduce copper concentrations in polluted waters.