Production de radicaux superoxydes par radiolyse pulsée de l'eau à transfert d'énergie linéique (TEL) élevé

2001 ◽  
Vol 79 (2) ◽  
pp. 180-183 ◽  
Author(s):  
G Baldacchino ◽  
V Trupin-Wasselin ◽  
S Bouffard ◽  
E Balanzat ◽  
M Gardès-Albert ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Aqueous Solution ◽  
Hydrogen Peroxide ◽  
Heavy Ions ◽  
Pulse Radiolysis ◽  
Direct Methods ◽  
Superoxide Anions ◽  
Radical Species ◽  
High Let ◽  
High Linear Energy Transfer

The radiolysis of water with heavy ions of high linear energy transfer (LET) (-dE/dx) is characterized, in deaerated medium, by the production of superoxide anions, the radiolytic yields of which increase with the LET. Radiobiological interest in such radical species comes from the oxidative stress which may be generated by their dismutation in O2 and H2O2 in anoxic medium (radiotherapy with heavy ions). A brief review of the measurements of superoxide free radicals in aqueous solution by indirect or direct methods is presented. Moreover, some experimental results obtained by pulse radiolysis with Ar18+ ions (TEL = 290 keV·µm-1), are described. The interpretation of the kinetics takes into account the superoxide absorbance and that of hydrogen peroxide, which is present at the millisecond time scale.Key words: pulse radiolysis, heavy ions, superoxide radicals, high LET, kinetics.[Traduit par la Rédaction]

Studies of radiation-induced reactions of ethylene in aqueous solution II. Reactions in the presence of oxygen as studied by pulse radiolysis and γ -irradiation techniques

1967 ◽  
Vol 300 (1463) ◽  
pp. 443-454 ◽  
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Peroxide ◽  
Rate Constants ◽  
Pulse Radiolysis ◽  
Major Product ◽  
Peroxy Radicals ◽  
Ferrous Ions ◽  
Constant Composition ◽  
Γ Irradiation ◽  
Radiation Induced

The radiolysis of dilute aqueous solutions containing ethylene and oxygen has been investigated. Pulse radiolysis was used to measure the rate constants for the addition of hydroxyl radicals to ethylene, the binary decomposition of the resulting hydroxyethyl radicals and their addition to ethylene and reaction with oxygen to yield peroxy radicals. The rate constants have also been determined for the mutual interaction of the peroxy radicals and their reaction with ferrous ions. The principal products of γ -irradiation were aldehydes and organic hydroperoxides. Hydrogen peroxide was found in yields close to the molecular yield from water. The polymer produced in the absence of oxygen was not formed, and glycollaldehyde, reported as a major product by previous workers, could not be detected. At constant composition of the gas mixtures, product yields were unaffected by total pressure in the range up to 40 atm, but were strongly dependent on the proportion of oxygen. Aldehyde yields were markedly greater at pH 1.2 than in neutral solution. The influence of ferrous ions an d of added hydrogen peroxide has been determined. The pulse radiolysis and γ -irradiation experiments complement one another and show that the radiation-induced oxidation of ethylene in aqueous solution involves the same primary reactions as occur in the absence of oxygen, followed by the formation and further reactions of peroxy radicals.

scholarly journals Coping with Reactive Oxygen Species to Ensure Genome Stability in Escherichia coli

Genes ◽  
2018 ◽  
Vol 9 (11) ◽  
pp. 565 ◽  
Author(s):  
Belén Mendoza-Chamizo ◽  
Anders Løbner-Olesen ◽  
Godefroid Charbon
Keyword(s):  
Oxidative Stress ◽  
Escherichia Coli ◽  
Cell Cycle ◽  
Hydrogen Peroxide ◽  
Reactive Oxygen ◽  
Single Strand ◽  
Aerobic Bacterium ◽  
Superoxide Anions ◽  
Strand Breaks ◽  
E Coli

The facultative aerobic bacterium Escherichia coli adjusts its cell cycle to environmental conditions. Because of its lifestyle, the bacterium has to balance the use of oxygen with the potential lethal effects of its poisonous derivatives. Oxidative damages perpetrated by molecules such as hydrogen peroxide and superoxide anions directly incapacitate metabolic activities relying on enzymes co-factored with iron and flavins. Consequently, growth is inhibited when the bacterium faces substantial reactive oxygen insults coming from environmental or cellular sources. Although hydrogen peroxide and superoxide anions do not oxidize DNA directly, these molecules feed directly or indirectly the generation of the highly reactive hydroxyl radical that damages the bacterial chromosome. Oxidized bases are normally excised and the single strand gap repaired by the base excision repair pathway (BER). This process is especially problematic in E. coli because replication forks do not sense the presence of damages or a stalled fork ahead of them. As consequence, single-strand breaks are turned into double-strand breaks (DSB) through replication. Since E. coli tolerates the presence of DSBs poorly, BER can become toxic during oxidative stress. Here we review the repair strategies that E. coli adopts to preserve genome integrity during oxidative stress and their relation to cell cycle control of DNA replication.

Mechanism of oxidative stress in skeletal muscle atrophied by immobilization

1993 ◽  
Vol 265 (6) ◽  
pp. E839-E844 ◽  
Author(s):  
H. Kondo ◽  
I. Nakagaki ◽  
S. Sasaki ◽  
S. Hori ◽  
Y. Itokawa
Keyword(s):  
Oxidative Stress ◽  
Skeletal Muscle ◽  
Hydrogen Peroxide ◽  
Superoxide Dismutase ◽  
High Performance ◽  
Superoxide Anions ◽  
Glutathione S Transferase ◽  
Sod Activity ◽  
Cytochemical Study ◽  
Male Wistar Rats

To clarify the mechanism of oxidative stress in skeletal muscle atrophied by immobilization, we measured the activities of antioxidant enzymes and xanthine oxidase (XOD) and carried out the cytochemical study of hydrogen peroxide in a typical slow red muscle, the soleus. Male Wistar rats (15 wk old), of which ankle joints of one hindlimb were immobilized in the fully extended position, were killed after 4, 8, or 12 days. The activities of Mn-containing superoxide dismutase (Mn-SOD), Cu-Zn-containing superoxide dismutase (Cu-Zn-SOD), Se-dependent glutathione peroxidase (Se-GSHPx), glutathione S-transferase, catalase, and glutathione reductase were measured spectrophotometrically. The XOD activity and the concentrations of hypoxanthine, xanthine, and urate were measured using a high-performance liquid chromatography. The cytochemical study of hydrogen peroxide in short-term organ culture was performed using an electron microscope. Increased Cu-Zn-SOD and decreased Mn-SOD in atrophy might reflect increased generation of superoxide anions in the cytoplasm rather than in the mitochondria. The source of superoxide anions in the cytoplasm might be the increased superoxide-producing XOD. Enhanced generation of superoxide anions and increased Cu-Zn-SOD activity in atrophy suggested the enhanced generation of hydrogen peroxide in the cytoplasm. Due to the unchanged activity of Se-GSHPx and the unchanged or slightly increased activity of catalase in atrophy, the ability to degrade hydrogen peroxide might not increase so much. Hence, hydrogen peroxide is expected to be increased in atrophy. The cytochemical study supported this expectation.(ABSTRACT TRUNCATED AT 250 WORDS)

A New Method for the Measurement of Low Concentrations of OH/O2-Radical Species in Water by High-LET Pulse Radiolysis. A Time-Resolved Chemiluminescence Study

2000 ◽  
Vol 104 (38) ◽  
pp. 8709-8714 ◽  
Author(s):  
V. Wasselin-Trupin ◽  
G. Baldacchino ◽  
S. Bouffard ◽  
E. Balanzat ◽  
M. Gardès-Albert ◽  
...  
Keyword(s):  
Pulse Radiolysis ◽  
New Method ◽  
Radical Species ◽  
Time Resolved ◽  
Low Concentrations ◽  
High Let

Pulse radiolysis of polymers in aqueous solution. Kinetics study

1997 ◽  
Vol 94 ◽  
pp. 244-250 ◽  
Author(s):  
I Janik ◽  
P Kujawa ◽  
P Ulanski ◽  
JM Rosiak
Keyword(s):  
Aqueous Solution ◽  
Pulse Radiolysis ◽  
Kinetics Study ◽  
Solution Kinetics

Effect of Turmeric and Ginger on Lipid Profile in Male Rats Exposed to Oxidative Stress

2019 ◽  
Vol 10 (01) ◽  
Author(s):  
Eman A. Al-Rekabi ◽  
Dheyaa K. Alomer ◽  
Rana Talib Al-Muswie ◽  
Khalid G. Al-Fartosi
Keyword(s):  
Oxidative Stress ◽  
Hydrogen Peroxide ◽  
Drinking Water ◽  
Lipid Profile ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Male Rats ◽  
Control Group ◽  
Very Low Density Lipoprotein ◽  
Low Density

The present study aimed to investigate the effect of turmeric and ginger on lipid profile of male rats exposed to oxidative stress induced by hydrogen peroxide H2O2 at a concentration of 1% given with consumed drinking water to male rats. Methods: 200 mg/kg from turmeric and ginger were used, and the animals were treatment for 30 days. Results: the results showed a significant increase in cholesterol, triglycerides, low density lipoprotein (LDL), very low density lipoprotein (VLDL), whereas it explained a significant decrease in high density lipoprotein (HDL) of male rats exposed to oxidative stress when compared with control group. the results showed a significant decrease in cholesterol, triglycerides, (LDL), (VLDL), whereas it explained a significant increase in (HDL) of rats treated with turmeric and ginger at dose 200 mg/kg when compared with male rats exposed to oxidative stress.

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