PEROXIDATION LEVELS IN ESCHERICHIA-COLI AS A POTENTIAL TOXICITY MARKER - EFFECT OF NICKEL AND METHYL-PARATHION

The effects of nickel and methyl-parathion were studied in subinhibiti ng concentrations (40 and 62.5 mug/mL, respectively) on the levels of cellular peroxidation in Escherichia coli. These effects were evaluate d using the thiobarbituric acid (TBA) test and the determination of li pofuscin-like substances. Both toxicants caused an increase in cellula r peroxidation levels, although at the concentrations used, nickel was shown to be a better inducer than methyl-parathion. The TBA test gave more significant differences than the determination of lipofuscin-lik e substances when the control cultures were compared to those containi ng the toxicant. This finding reveals that the TBA test could be used as a toxicity marker in E. coli for the development of ecotoxicity bio tests. (C) 1994 by John Wiley & Sons, Inc.