Journal ArticleDOI
Toxic DNA damage by hydrogen peroxide through the Fenton reaction in vivo and in vitro.
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
Citations
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Antioxidant Activities of Streptomyces sp. strain MUSC 14 from Mangrove Forest Soil in Malaysia.
Hefa Mangzira Kemung,Loh Teng Hern Tan,Loh Teng Hern Tan,Kok-Gan Chan,Kok-Gan Chan,Hooi-Leng Ser,Hooi-Leng Ser,Jodi Woan-Fei Law,Jodi Woan-Fei Law,Learn Han Lee,Bey Hing Goh,Bey Hing Goh +11 more
TL;DR: The present study suggests that Streptomyces sp.
Journal ArticleDOI
Synergistic cytotoxicity between pentachlorophenol and copper in a bacterial model.
TL;DR: Exposing bacteria to a combination of PCP and copper at non- or sub-toxic concentrations resulted in enhanced cytotoxic effect in a synergistic mode as indicated by both the inhibition of growth and the lowering of the colony-forming ability.
Journal ArticleDOI
Purification and some properties of Cu,Zn superoxide dismutase from Radix lethospermi seed, kind of Chinese traditional medicine
Namir I. A. Haddad,Qinsheng Yuan +1 more
TL;DR: Copper-zinc superoxide dismutase (Cu,Zn SOD) has been extracted, purified and characterized from Radix lethospermi seed (RLS), a kind of Chinese traditional medicine and appeared to have significant thermal stability lower than other Cu,ZN SODs, as revealed by irreversible heat inactivation at 60 degrees C.
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A mutant endonuclease IV of Escherichia coli loses the ability to repair lethal DNA damage induced by hydrogen peroxide but not that induced by methyl methanesulfonate.
TL;DR: It is concluded that the endonuclease IV186 protein is specifically deficient in the ability to remove 3'-terminus-blocking damage, which is required for DNA repair synthesis, and it is possible that the lethal DNA damage by H2O2 is 3'-blocking damage and not AP-site damage.
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.