title: Cytocidal and filamentous response of Escherichia coli cells exposed to low concentrations of hydrogen peroxide and hydroxyl radical scavengers.
abstract: The hydroxyl radical scavengers thiourea, ethanol, and dimethyl sulfoxide significantly reduced the killing of Escherichia coli elicited by low concentrations of H2O2 (resulting in mode 1 killing) when treatments with the oxidant and the scavengers were performed in a complete growth medium (K medium) but not in M9 salts. In addition, thiourea efficiently prevented the toxic response to high concentrations of H2O2 (resulting in mode 2 killing) under both exposure conditions. Sod A cells, which do not respond with a bimodal pattern of toxicity when challenged with increasing concentrations of H2O2, were markedly protected by thiourea against the lethal action of various levels of the oxidant (which in the wild-type strain result in either mode 1 or mode 2 killing) under conditions of treatments in both K medium and M9 salts. In some experiments, wild-type cells were challenged with a low concentration of H2O2 (in the absence or presence of hydroxyl radical scavengers) and then postincubated in fresh K medium for various time intervals. It was found that scavengers were able to inhibit the filamentous response generated by exposure to the oxidant in K medium. Both the length and the number of filaments were markedly reduced. Treatment in M9 salts resulted in a limited number of very short filaments, and this response was slightly reduced by the scavengers.
authors.affiliation: Institute of Toxicologic, Hygienic and Environmental Science, University of Urbino, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Brandi
authors.forename: L
authors.initials: L
authors.lastname: Salvaggio
authors.forename: F
authors.initials: F
authors.lastname: Cattabeni
authors.forename: O
authors.initials: O
authors.lastname: Cantoni
mesh_terms: D004121:Dimethyl Sulfoxide / Q000494:pharmacology*; D004926:Escherichia coli / Q000166:cytology / Q000187:drug effects / Q000254:growth & development*; D000431:Ethanol / Q000494:pharmacology*; D016166:Free Radical Scavengers; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D013890:Thiourea / Q000494:pharmacology*
chemical_list: D016166:Free Radical Scavengers; D000431:Ethanol; D006861:Hydrogen Peroxide; D013890:Thiourea; D004121:Dimethyl Sulfoxide