Journal ArticleDOI
Toxic DNA damage by hydrogen peroxide through the Fenton reaction in vivo and in vitro.
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TLDR
An in vitro Fenton system was established that generates DNA strand breaks and inactivates bacteriophage and that also reproduces the suppression of DNA damage by high concentrations of peroxide.Abstract:
Exposure of Escherichia coli to low concentrations of hydrogen peroxide results in DNA damage that causes mutagenesis and kills the bacteria, whereas higher concentrations of peroxide reduce the amount of such damage. Earlier studies indicated that the direct DNA oxidant is a derivative of hydrogen peroxide whose formation is dependent on cell metabolism. The generation of this oxidant depends on the availability of both reducing equivalents and an iron species, which together mediate a Fenton reaction in which ferrous iron reduces hydrogen peroxide to a reactive radical. An in vitro Fenton system was established that generates DNA strand breaks and inactivates bacteriophage and that also reproduces the suppression of DNA damage by high concentrations of peroxide. The direct DNA oxidant both in vivo and in this in vitro system exhibits reactivity unlike that of a free hydroxyl radical and may instead be a ferryl radical.read more
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Effect of oxygen on the anaerobic methanotroph 'Candidatus Methylomirabilis oxyfera': kinetic and transcriptional analysis.
Francisca A. Luesken,Ming L. Wu,Huub J. M. Op den Camp,Jan T. Keltjens,Henk Stunnenberg,Kees-Jan Francoijs,Marc Strous,Mike S. M. Jetten +7 more
TL;DR: The results show that oxygen-exposed cells of M. oxyfera were under oxidative stress and that in spite of its oxygenic capacity, exposure to microoxic conditions has an overall detrimental effect.
Journal ArticleDOI
Reduced flavins promote oxidative DNA damage in non-respiring Escherichia coli by delivering electrons to intracellular free iron.
Anh N. Woodmansee,James A. Imlay +1 more
TL;DR: The rate of oxidative DNA damage can be limited by the rate at which electron donors reduce free iron, and reduced flavins become the predominant donors in E. coli when respiration is blocked.
Journal ArticleDOI
Enhanced respiration prevents drug tolerance and drug resistance in Mycobacterium tuberculosis
Catherine Vilchèze,Travis Hartman,Brian Weinrick,Brian Weinrick,Paras Jain,Torin R. Weisbrod,Lawrence W. Leung,Joel S. Freundlich,William R. Jacobs +8 more
TL;DR: It is discovered that the combination of cysteine or other small thiols with either isoniazid or rifampicin prevents the formation of drug-tolerant and drug-resistant cells in Mtb cultures, leading to mycobacterial cell death.
Journal ArticleDOI
Melatonin provides neuroprotection in the late-gestation fetal sheep brain in response to umbilical cord occlusion
TL;DR: Brief asphyxia results in significant and delayed entry of ·OH into the extracellular space of cortical gray matter in the fetal sheep brain, and melatonin given to the mother at the time of the insult abrogates this increase.
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Mechanism of H2S-mediated protection against oxidative stress in Escherichia coli.
Alexander Mironov,T. A. Seregina,Maxim Nagornykh,Lyly Luhachack,Natalya Korolkova,Liubov Errais Lopes,Vera Kotova,Gennady Zavilgelsky,R. S. Shakulov,Konstantin Shatalin,Evgeny Nudler,Evgeny Nudler +11 more
TL;DR: It is reported that 3-mercaptopyruvate sulfurtransferase (3MST) is the major source of endogenous H2S in Escherichia coli and 3MST protects E. coli against oxidative stress via l-cysteine utilization and H 2S-mediated sequestration of free iron necessary for the genotoxic Fenton reaction.
References
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Journal ArticleDOI
The biology of oxygen radicals
TL;DR: The reactive superoxide radical, O2-, formerly of concern only to radiation chemists and radiobiologists, is now understood to be a normal product of the biological reduction of molecular oxygen.
Journal ArticleDOI
The catalytic decomposition of hydrogen peroxide by iron salts
Fritz Haber,Joseph Weiss +1 more
TL;DR: Wansbrough-Jones as discussed by the authors gave the manuscript of this paper to Professor Sir William Pope, but the final revision for the press had not been made and in its original from the paper was not suitable for publication in an English journal; but since, Professor Haber had considered carefully how he wished to present the results embodied in it, the form and sequence of the paper remain unmodified.