Hydrogen Peroxide Effects on Chromium Oxidation State and Solubility in Four Diverse, Chromium-Enriched Soils

2001 ◽  
Vol 35 (20) ◽  
pp. 4054-4059 ◽  
Author(s):  
Melanie L. Rock ◽  
Bruce R. James ◽  
George R. Helz
Keyword(s):  
Hydrogen Peroxide ◽  
Oxidation State ◽  
Chromium Oxidation

Chromium oxidation state mapping in human cells

2003 ◽  
Vol 104 ◽  
pp. 289-292 ◽  
Author(s):  
R. Ortega ◽  
B. Fayard ◽  
M. Salomé ◽  
G. Devès ◽  
J. Susini
Keyword(s):  
Oxidation State ◽  
Human Cells ◽  
Chromium Oxidation

scholarly journals Phase Variation of Ag43 Is Independent of the Oxidation State of OxyR

2003 ◽  
Vol 185 (7) ◽  
pp. 2203-2209 ◽  
Author(s):  
Anu Wallecha ◽  
Jason Correnti ◽  
Vincent Munster ◽  
Marjan van der Woude
Keyword(s):  
Oxidative Stress ◽  
Hydrogen Peroxide ◽  
Oxidation State ◽  
Regulatory Region ◽  
Phase Variation ◽  
In Vitro Transcription ◽  
Reduced Form ◽  
Target Sequences

ABSTRACT OxyR is a DNA binding protein that differentially regulates a cell's response to hydrogen peroxide-mediated oxidative stress. We previously reported that the reduced form of OxyR is sufficient for repression of transcription of agn43 from unmethylated template DNA, which is essential for deoxyadenosine methylase (Dam)- and OxyR-dependent phase variation of agn43. Here we provide evidence that the oxidized form of OxyR [OxyR(ox)] also represses agn43 transcription. In vivo, we found that exogenous addition of hydrogen peroxide, sufficient to oxidize OxyR, did not affect the expression of agn43. OxyR(ox) repressed in vitro transcription but only from an unmethylated agn43 template. The −10 sequence of the promoter and three Dam target sequences were protected in an in vitro DNase I footprint assay by OxyR(ox). Furthermore, OxyR(ox) bound to the agn43 regulatory region DNA with an affinity similar to that for the regulatory regions of katG and oxyS, which are activated by OxyR(ox), indicating that binding at agn43 can occur at biologically relevant concentrations. OxyR-dependent regulation of Ag43 expression is therefore unusual in firstly that OxyR binding at agn43 is dependent on the methylation state of Dam target sequences in its binding site and secondly that OxyR-dependent repression appears to be independent of hydrogen-peroxide mediated oxidative stress and the oxidation state of OxyR.

Chromium Oxidation State Imaging in Mammalian Cells Exposed in Vitro to Soluble or Particulate Chromate Compounds

2005 ◽  
Vol 18 (10) ◽  
pp. 1512-1519 ◽  
Author(s):  
Richard Ortega ◽  
Barbara Fayard ◽  
Murielle Salomé ◽  
Guillaume Devès ◽  
Jean Susini
Keyword(s):  
Oxidation State ◽  
Mammalian Cells ◽  
Chromium Oxidation

scholarly journals The Direct Synthesis of Hydrogen Peroxide over AuPd Nanoparticles: An Investigation into Metal Loading

2021 ◽  
Author(s):  
Joseph Brehm ◽  
Richard J. Lewis ◽  
David J. Morgan ◽  
Thomas E. Davies ◽  
Graham J. Hutchings
Keyword(s):  
Hydrogen Peroxide ◽  
Catalytic Activity ◽  
Oxidation State ◽  
Direct Synthesis ◽  
Catalytic Performance ◽  
Metal Loading ◽  
Subsequent Degradation ◽  
Small Nanoparticles

AbstractThe direct synthesis of H2O2 from molecular H2 and O2 over AuPd catalysts, supported on TiO2 and prepared via an excess chloride co-impregnation procedure is investigated. The role of Au:Pd ratio on the catalytic activity towards H2O2 formation and its subsequent degradation is evaluated under conditions that have previously been found to be optimal for the formation of H2O2. The combination of relatively small nanoparticles, of mixed Pd-oxidation state is shown to correlate with enhanced catalytic performance. Subsequently, a detailed study of catalytic activity towards H2O2 synthesis as a function of AuPd loading was conducted, with a direct correlation between catalytic activity and metal loading observed. Graphic Abstract

Investigations of changes in the oxidation state of the catalyst during the OsO4-catalysed decomposition of hydrogen peroxide

Polyhedron ◽  
1982 ◽  
Vol 1 (2) ◽  
pp. 175-177 ◽  
Author(s):  
Zoltán M. Galbács ◽  
László Nagy ◽  
László J. Csányi
Keyword(s):  
Hydrogen Peroxide ◽  
Oxidation State
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