scholarly journals Composition Directed Generation of Reactive Oxygen Species in Irradiated Mixed Metal Sulfides Correlated with Their Photocatalytic Activities

2015 ◽  
Vol 7 (30) ◽  
pp. 16440-16449 ◽  
Author(s):  
Weiwei He ◽  
Huimin Jia ◽  
Dongfang Yang ◽  
Pin Xiao ◽  
Xiaoli Fan ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Reactive Oxygen ◽  
Metal Sulfides ◽  
Oxygen Species ◽  
Mixed Metal ◽  
Photocatalytic Activities

Reactive Oxygen Species Influence Biofilm Formation of Acidophilic Mineral-Oxidizing Bacteria on Pyrite

2015 ◽  
Vol 1130 ◽  
pp. 118-122 ◽  
Author(s):  
Sören Bellenberg ◽  
Dieu Huynh ◽  
Laura Castro ◽  
Maria Boretska ◽  
Wolfgang Sand ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Hydroxyl Radicals ◽  
Biofilm Formation ◽  
Laser Scanning ◽  
Reactive Oxygen ◽  
Laser Scanning Microscopy ◽  
Metal Sulfides ◽  
Confocal Laser ◽  
Water Molecules ◽  
Oxygen Species

Reactive oxygen species (ROS), such as hydrogen peroxide (H2O2), superoxide (O2-) and hydroxyl radicals (OH.) are known to be formed on the surface of metal sulfides in aqueous solution under oxic and anoxic conditions. Consequently bacteria which have not been adapted to their presence are metabolically inhibited [1], presumably due to the presence of these ROS. Pyrite-grown cells ofAcidithiobacillus ferrooxidansT, in contrast to iron (II)-grown cells, were able to oxidize iron (II)-ions or pyrite after 24 h starvation and contact with 1 mM externally added H2O2. In this study, similar results were obtained withAcidiferrobactersp. SPIII/3. However,Acidithiobacillus ferrivoransSS3 showed the highest tolerance towards contact with H2O2, whileLeptospirillum ferrooxidansDSM 2391 was most sensitive. Similar results were obtained after exposure to defined doses of gamma radiation, which cleaves water molecules and generates ROS. In this study members of the three aforementioned genera of mineral-oxidizing bacteria were compared regarding their ability to survive, colonize pyrite and to oxidize iron (II)-ions after exposure to different concentrations of H2O2. Pyrite colonization was studied after exposure to endogenous ROS formed on pyrite or after external addition of H2O2using confocal laser scanning microscopy (CLSM).

Mitochondria as a source of reactive oxygen species

2009 ◽  
pp. c3 ◽  
Author(s):  
Helena M. Cochemé ◽  
Michael P. Murphy
Keyword(s):  
Reactive Oxygen Species ◽  
Reactive Oxygen ◽  
Oxygen Species

Clinical aspects of reactive oxygen and nitrogen species

2004 ◽  
Vol 71 ◽  
pp. 121-133 ◽  
Author(s):  
Ascan Warnholtz ◽  
Maria Wendt ◽  
Michael August ◽  
Thomas Münzel
Keyword(s):  
Oxidative Stress ◽  
Reactive Oxygen Species ◽  
Risk Factor ◽  
Endothelial Dysfunction ◽  
Vascular Tissue ◽  
Rapid Development ◽  
Reactive Oxygen ◽  
Clinical Aspects ◽  
No Production ◽  
Oxygen Species

Endothelial dysfunction in the setting of cardiovascular risk factors, such as hypercholesterolaemia, hypertension, diabetes mellitus and chronic smoking, as well as in the setting of heart failure, has been shown to be at least partly dependent on the production of reactive oxygen species in endothelial and/or smooth muscle cells and the adventitia, and the subsequent decrease in vascular bioavailability of NO. Superoxide-producing enzymes involved in increased oxidative stress within vascular tissue include NAD(P)H-oxidase, xanthine oxidase and endothelial nitric oxide synthase in an uncoupled state. Recent studies indicate that endothelial dysfunction of peripheral and coronary resistance and conductance vessels represents a strong and independent risk factor for future cardiovascular events. Ways to reduce endothelial dysfunction include risk-factor modification and treatment with substances that have been shown to reduce oxidative stress and, simultaneously, to stimulate endothelial NO production, such as inhibitors of angiotensin-converting enzyme or the statins. In contrast, in conditions where increased production of reactive oxygen species, such as superoxide, in vascular tissue is established, treatment with NO, e.g. via administration of nitroglycerin, results in a rapid development of endothelial dysfunction, which may worsen the prognosis in patients with established coronary artery disease.

Fas ligand expression in rat kupffer cells in response to lipopolysaccharide is mediated by reactive oxygen species

2001 ◽  
Vol 120 (5) ◽  
pp. A361-A361
Author(s):  
K UCHIKURA ◽  
T WADA ◽  
Z SUN ◽  
S HOSHINO ◽  
G BULKLEY ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Kupffer Cells ◽  
Fas Ligand ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Ligand Expression
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